Podcasts about lrrk2

Inflammation appears to affect almost every part of the human body as we age, including cancer, type-2 diabetes, obesity, and neurodegenerative disorders.NLRP3 inflammasome-induced inflammation is at the root of nearly all disease pathologies including fibrotic, dermatological, rheumatological diseases as well as neurological disorders such as Alzheimer's disease.Halia Therapeutics is a clinical-stage biopharmaceutical company pioneering a novel class of small molecule medications designed to combat inflammation.Halia Therapeutics' candidates are the first drugs to target the protein NEK7 to inhibit NLRP3 inflammasome activity to resolve chronic inflammation in multiple diseases.Its lead candidate, HT-6184 is currently being evaluated in two phase II studies – for the treatment of post-procedure inflammatory pain response and cancer (lower-risk myelodysplastic syndromes (LR-MDS).The company also recently announced a new collaboration to leverage AI in the clinical development of its new Alzheimer's disease drug, HT-4253, targeting a mediator of neuroinflammation called leucine-rich repeat kinase 2 (LRRK2).This week, or guest is Dave Bearss, CEO of Halia Therapeutics.01:09-05:49: About Halia Therapeutics05:49-08:59: What is the difference between acute inflammation and chronic inflammation?08:59-12:02: What is NLRP3 inflammasome-induced inflammation?12:02-15:37: What is NEK7 and how does targeting it help inhibit NLRP3 inflammasome activity?15:37-18:51: What diseases are related to NLRP3 inflammasome activity?18:51-22:11: What does reducing NLRP3 activity address in these conditions?22:11-26:46:  With Alzheimer's and Parkinson's is inflammation reduction being investigated by other companies?26:46-24:14: What is Halia's lead candidate, HT-6184?34:14-37:03: What is the balance between normal inflammation and reducing chronic inflammation?37:03-38:34: Is early intervention the key?38:34-42:18: Would your treatment be good as a preventative measure?Interested in being a sponsor of an episode of our podcast? Discover how you can get involved here! Stay updated by subscribing to our newsletter

A growing body of evidence is expanding our understanding of the links between inflammation, our immune responses, brain health, and neurodegeneration. In particular, several genes associated with Parkinson's (including LRRK2) are known to be involved in inflammation, and peripheral inflammation has been shown to influence brain function and contribute to the development of neurodegenerative diseases. Better understanding the roles of inflammation and our immune responses in Parkinson's disease is important for developing new treatments and strategies to slow or prevent disease progression. In this episode, Dr. Malú Gámez Tansey talks about her research at the intersection of immunology, neuroscience, and genetics. She describes new findings and current projects in her lab, discusses advances in neuroimmunology, and shares her insights on important areas of opportunity in the field. Malú is the Norman and Susan Fixel Chair in Parkinson's Disease, Professor of Neuroscience and Neurology, and Director of the Parkinson's Foundation Research Center of Excellence at the University of Florida College of Medicine. She's also editor-in-chief of Nature Partner Journal Parkinson's Disease.This podcast is geared toward researchers and clinicians. If you live with Parkinson's or have a friend or family member with PD, listen to The Michael J. Fox Foundation Parkinson's Podcast. Hear from scientists, doctors and people with Parkinson's on different aspects of life with the disease as well as research toward treatment breakthroughs at https://www.michaeljfox.org/podcasts.

A growing body of evidence is expanding our understanding of the links between inflammation, our immune responses, brain health, and neurodegeneration. In particular, several genes associated with Parkinson's (including LRRK2) are known to be involved in inflammation, and peripheral inflammation has been shown to influence brain function and contribute to the development of neurodegenerative diseases. Better understanding the roles of inflammation and our immune responses in Parkinson's disease is important for developing new treatments and strategies to slow or prevent disease progression. In this episode, Dr. Malú Gámez Tansey talks about her research at the intersection of immunology, neuroscience, and genetics. She describes new findings and current projects in her lab, discusses advances in neuroimmunology, and shares her insights on important areas of opportunity in the field. Malú is the Norman and Susan Fixel Chair in Parkinson's Disease, Professor of Neuroscience and Neurology, and Director of the Parkinson's Foundation Research Center of Excellence at the University of Florida College of Medicine. She's also editor-in-chief of Nature Partner Journal Parkinson's Disease.This podcast is geared toward researchers and clinicians. If you live with Parkinson's or have a friend or family member with PD, listen to The Michael J. Fox Foundation Parkinson's Podcast. Hear from scientists, doctors and people with Parkinson's on different aspects of life with the disease as well as research toward treatment breakthroughs at https://www.michaeljfox.org/podcasts.

Mutations in the LRRK2 gene were first linked to Parkinson's disease (PD) risk in 2004. Since then, researchers from around the world have advanced our understanding of the mechanisms through which LRRK2 may contribute to PD, leading to the development of three potential LRRK2-targeted therapies that are now being evaluated in clinical trials. Along with colleagues and collaborators, Dr. Dario Alessi has pioneered new research and approaches that have aided in the development of drugs to inhibit LRRK2 and potentially treat people with Parkinson's disease. In this episode Dario discusses his work developing the LRRK2 kinase assay, LRRK2 Ser935 dephosphorylation assay, and Rab phosphorylation assay, as well as future directions and opportunities in the field. This year, Dario received the 2023 Robert A. Pritzker Prize for Leadership in Parkinson's Research for his substantial research contribution and his commitment to mentoring the next generation of Parkinson's scientists. Dario is the Professor of Signal Transduction and Science Director of the Medical Research Council Protein Phosphorylation and Ubiquitylation Unit at the University of Dundee.This podcast is geared toward researchers and clinicians. If you live with Parkinson's or have a friend or family member with PD, listen to The Michael J. Fox Foundation Parkinson's Podcast. Hear from scientists, doctors and people with Parkinson's on different aspects of life with the disease as well as research toward treatment breakthroughs at https://www.michaeljfox.org/podcasts.

Mutations in the LRRK2 gene were first linked to Parkinson's disease (PD) risk in 2004. Since then, researchers from around the world have advanced our understanding of the mechanisms through which LRRK2 may contribute to PD, leading to the development of three potential LRRK2-targeted therapies that are now being evaluated in clinical trials. Along with colleagues and collaborators, Dr. Dario Alessi has pioneered new research and approaches that have aided in the development of drugs to inhibit LRRK2 and potentially treat people with Parkinson's disease. In this episode Dario discusses his work developing the LRRK2 kinase assay, LRRK2 Ser935 dephosphorylation assay, and Rab phosphorylation assay, as well as future directions and opportunities in the field. This year, Dario received the 2023 Robert A. Pritzker Prize for Leadership in Parkinson's Research for his substantial research contribution and his commitment to mentoring the next generation of Parkinson's scientists. Dario is the Professor of Signal Transduction and Science Director of the Medical Research Council Protein Phosphorylation and Ubiquitylation Unit at the University of Dundee.This podcast is geared toward researchers and clinicians. If you live with Parkinson's or have a friend or family member with PD, listen to The Michael J. Fox Foundation Parkinson's Podcast. Hear from scientists, doctors and people with Parkinson's on different aspects of life with the disease as well as research toward treatment breakthroughs at https://www.michaeljfox.org/podcasts.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.31.551097v1?rss=1 Authors: Duffy, M., Ding, J., Langston, R. G., Shah, S. I., Nalls, M. A., Scholz, S. W., Whitaker, D. T., Auluck, P. K., Gibbs, J. R., Marenco, S., Cookson, M. R. Abstract: Age is a major common risk factor underlying neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease, and amyotrophic lateral sclerosis. Previous studies reported that chronological age correlates with differential gene expression across different brain regions. However, prior datasets have not disambiguated whether expression associations with age are due to changes in cell numbers and/or gene expression per cell. In this study, we leveraged single nucleus RNA-sequencing (snRNAseq) to examine changes in cell proportions and transcriptomes in four different brain regions, each from 12 donors aged 20-30 years (young) or 60-85 years (old). We sampled 155,192 nuclei from two cortical regions (entorhinal cortex and middle temporal gyrus) and two subcortical regions (putamen and subventricular zone) relevant to neurodegenerative diseases or the proliferative niche. We found no changes in cellular composition of different brain regions with healthy aging. Surprisingly, we did find that each brain region has a distinct aging signature, with only minor overlap in differentially associated genes across regions. Moreover, each cell type shows distinct age-associated expression changes, including loss of protein synthesis genes in cortical inhibitory neurons, axonogenesis genes in excitatory neurons and oligodendrocyte precursor cells, enhanced gliosis markers in astrocytes and disease-associated markers in microglia, and genes critical for neuron-glia communication. Importantly, we find cell type-specific enrichments of age associations with genes nominated by Alzheimer's disease and Parkinson's disease genome-wide association studies (GWAS), such as apolipoprotein E (APOE), and leucine-rich repeat kinase 2 (LRRK2) in microglia that are independent of overall expression levels across cell types. We present this data as a new resource which highlights, first, region- and cell type-specific transcriptomic changes in healthy aging that may contribute to selective vulnerability and, second, provide context for testing GWAS-nominated disease risk genes in relevant subtypes and developing more targeted therapeutic strategies. The data is readily accessible without requirement for extensive computational support in a public website, https://brainexp-hykyffa56a-uc.a.run.app/ . Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.25.550521v1?rss=1 Authors: Dou, D., Aiken, J., Holzbaur, E. L. F. Abstract: Gain-of-function mutations in the LRRK2 gene cause Parkinson's disease (PD), characterized by debilitating motor and non-motor symptoms. Increased phosphorylation of a subset of RAB GTPases by LRRK2 is implicated in PD pathogenesis. We find that increased phosphorylation of RAB3A, a cardinal synaptic vesicle precursor (SVP) protein, disrupts anterograde axonal transport of SVPs in iPSC-derived human neurons (iNeurons) expressing hyperactive LRRK2-p.R1441H. Knockout of the opposing protein phosphatase 1H (PPM1H) in iNeurons phenocopies this effect. In these models, the compartmental distribution of synaptic proteins is altered; synaptophysin and synaptobrevin-2 become sequestered in the neuronal soma with decreased delivery to presynaptic sites along the axon. We find that RAB3A phosphorylation disrupts binding to the motor adapter MADD, potentially preventing formation of the RAB3A-MADD-KIF1A/1B{beta} complex driving anterograde SVP transport. RAB3A hyperphosphorylation also disrupts interactions with RAB3GAP and RAB-GDI1. Our results reveal a mechanism by which pathogenic hyperactive LRRK2 may contribute to the altered synaptic homeostasis associated with characteristic non-motor and cognitive manifestations of PD. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.14.549028v1?rss=1 Authors: Wallings, R., Mark, J., Staley, H., Gillett, D., Neighbarger, N., hirst, w., Kordasiewicz, H., Tansey, M. G. Abstract: Genetic variation around the LRRK2 gene affects risk of both familial and sporadic Parkinson's disease (PD). LRRK2 levels have become an appealing target for potential PD-therapeutics with LRRK2 antisense oligonucleotides (ASOs) now in clinical trials. However, LRRK2 has been suggested to play a fundamental role in peripheral immunity, and it is currently unknown if targeting increased LRRK2 levels in peripheral immune cells will be beneficial or deleterious. Furthermore, the precise role of LRRK2 in immune cells is currently unknown, although it has been suggested that LRRK2-mediated lysosomal function may be crucial to immune responses. Here, it was observed that G2019S macrophages exhibited increased stimulation-dependent lysosomal tubule formation (LTF) and MHC-II trafficking from the perinuclear lysosome to the plasma membrane in an mTOR dependent manner with concomitant increases in pro-inflammatory cytokine release. Both ASO-mediated knock down of mutant Lrrk2 and LRRK2 kinase inhibition ameliorated this phenotype and decreased these immune responses in control cells. Given the critical role of antigen presentation, lysosomal function, and cytokine release in macrophages, it is likely LRRK2-targetting therapies may have therapeutic value with regards to mutant LRRK2 but deleterious effects on the peripheral immune system, such as altered pathogen control and infection resolution. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.12.548710v1?rss=1 Authors: Meneses-Salas, E., Arnold, M., Hsieh, F., Enrich, C., Pfeffer, S. R., Merchant, K. M., Lu, A. Abstract: Background: The endo-lysosomal phospholipid, bis(monoacylglycerol)phosphate (BMP), is aberrantly high in the urine of Parkinson's patients with mutations in genes encoding leucine-rich repeat kinase 2 (LRRK2) and glucocerebrosidase (GCase). Because BMP resides on and regulates the biogenesis of endo-lysosomal intralumenal membranes (exosomes when released), we hypothesized that elevated urinary BMP may be driven by increased exocytosis of BMP-enriched exosomes. Objective: Our aim was to explore the contribution of LRRK2 and GCase activities in the regulation of BMP metabolism and release. Methods: Microscopy and biochemical assays were used to analyze antibody-accessible BMP and exosome release in wild type (WT) and R1441G LRRK2-expressing mouse embryonic fibroblast cells. Lipidomics analysis was conducted to measure BMP and lipid content in cells and isolated exosomes. In these experiments, we tested the effects of LRRK2 and GCase inhibitors, MLi-2 and conduritol {beta}-epoxide respectively, to assess regulation of BMP by LRRK2 and GCase. Results: Alterations in antibody-accessible BMP and endo-lysosome morphology were detected in R1441G LRRK2 cells. Lipidomics analysis revealed increased BMP content in mutant LRRK2 MEFs compared to WT MEFs. Inhibition of LRRK2 partially restored cellular and exosome-associated BMP levels; abrogation of GCase activity had the opposite effect. Metabolic labeling experiments confirmed that BMP synthesis is not influenced by LRRK2 or GCase activities. Pharmacological modulation of exosome release further confirmed exosome-mediated BMP exocytosis. Conclusions: LRRK2 regulates BMP in cells and its release in exosomes, which can be further modulated by GCase activity. These results have implications for the use of exosomal BMP as a Parkinson's disease biomarker. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Welcome to the NeurologyLive® Mind Moments® podcast. Tune in to hear leaders in neurology sound off on topics that impact your clinical practice. In this episode, we spoke with Ann Marie Morse, DO, FAAN, a pediatric neurologist and sleep medicine specialist at Geisinger Medical Center, who sat down with NeurologyLive at the annual SLEEP meeting to discuss the landscape of challenges narcolepsy-related challenges that patients face, the influence of gut health on sleep apnea, how nighttime disruptions can affect treatment decisions, emerging concepts of care, and much more. Looking for more Sleep Disorder discussion? Check out the NeurologyLive® sleep disorder clinical focus page. Episode Breakdown: 1:15 – Factors at play in obstructive sleep apnea 3:40 – Literature on the gut microbiome's role in sleep 5:55 – Lingering needs in narcolepsy treatment 8:30 – Neurology News Minute 12:40 – The effect of disrupted nighttime sleep 15:45 – Emerging concepts in sleep medicine This episode is brought to you by Medical World News, a streaming channel from MJH Life Sciences®. Check out new content and shows every day, only at medicalworldnews.com. The stories featured in this week's Neurology News Minute, which will give you quick updates on the following developments in neurology, are further detailed here: Biogen and Denali Terminate Phase 3 LIGHTHOUSE Study of BIIB122 in LRRK2-related Parkinson Disease FibroGen's Duchenne Muscular Dystrophy Antibody Pamrevlumab Falls Short in Phase 3 Phase 2/3 Study of Blarcamesine in Pediatrics With Rett Syndrome Completes Enrollment FDA Places Hold on Phase 1 Study of Exon Skipping Therapy PGN-EDODM1 in Myotonic Muscular Dystrophy FDA Panel Votes in Favor of Eisai's Lecanemab for Early Alzheimer Disease Post-Marketing Study of Andexanet Alfa Stopped Early After Achieving Prespecified Efficacy Thanks for listening to the NeurologyLive® Mind Moments® podcast. To support the show, be sure to rate, review, and subscribe wherever you listen to podcasts. For more neurology news and expert-driven content, visit neurologylive.com.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.30.538317v1?rss=1 Authors: Mamais, A., Sanyal, A., Fajfer, A., Zykoski, C. G., Guldin, M., Riley-DiPaolo, A., Subrahmanian, N., Gibbs, W. S., Lin, S., LaVoie, M. J. Abstract: Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.28.538525v1?rss=1 Authors: Giusto, E., Maistrello, L., Iannotta, L., Giusti, V., Iovino, L., Bandopadhyay, R., Antonini, A., Bubacco, L., Barresi, R., Plotegher, N., Greggio, E., Civiero, L. Abstract: Background: Parkinson's disease is a progressive neurodegenerative disorder mainly distinguished by sporadic aetiology, although a genetic component is also well established. Variants in the LRRK2 gene are associated with both familiar and sporadic disease. We have previously shown that PAK6 and 14-3-3gamma protein interact with and regulate the activity of LRRK2. Objectives: The aim of this study is to quantify PAK6 and 14-3-3gamma in plasma as a reliable biomarker strategy for the diagnosis of both sporadic and LRRK2-linked Parkinson's disease. Methods: After an initial quantification of PAK6 and 14-3-3gamma expression by means of Western blot in post-mortem human brains, we verified the presence of the two proteins in plasma by using quantitative ELISA tests. We analysed samples obtained from 39 healthy subjects, 40 patients with sporadic Parkinson's disease, 50 LRRK2-G2019S non-manifesting carriers and 31 patients with LRRK2-G2019S Parkinson's disease. Results: The amount of PAK6 and 14-3-3gamma is significantly different in patients with Parkinson's disease compared to healthy subjects. Moreover, the amount of PAK6 also varies with the presence of the G2019S mutation in the LRRK2 gene. Although the generalized linear models show a low association between the presence of PD and PAK6, the kinase can be added in a broader panel of biomarkers for the diagnosis of Parkinson's disease. Conclusions: Changes of PAK6 and 14-3-3gamma amount in plasma represent a shared readout for patients affected by sporadic and LRRK2-linked Parkinson's disease. Overall, they can contribute to the establishment of an extended panel of biomarkers for the diagnosis of Parkinson's disease. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.11.536367v1?rss=1 Authors: Naaldijk, Y., Fernandez, B., Fasiczka, R., Fdez, E., Leghay, C., Croitoru, I., Kwok, J. B., Boulesnane, Y., Vizeneux, A., Mutez, E., Calvez, C., Destee, A., Taymans, J.-M., Vinagre Aragon, A., Bergareche Yarza, A., Padmanabhan, S., Delgado, M., Alcalay, R. N., Chatterton, Z., Dzamko, N., Halliday, G., Ruiz-Martinez, J., Chartier-Harlin, M.-C., Hilfiker, S. Abstract: Parkinson's disease (PD) is a common neurodegenerative movement disorder and leucine-rich repeat kinase 2 (LRRK2) is a promising therapeutic target for disease intervention. However, the ability to stratify patients who will benefit from such treatment modalities based on shared etiology is critical for the success of disease-modifying therapies. Ciliary and centrosomal alterations are commonly associated with pathogenic LRRK2 kinase activity and can be detected in many cell types. We previously found centrosomal deficits in immortalized lymphocytes from G2019S-LRRK2 PD patients. Here, to investigate whether such deficits may serve as a potential blood biomarker for PD which is susceptible to LRKK2 inhibitor treatment, we characterized patient-derived cells from distinct PD cohorts. We report centrosomal alterations in peripheral cells from a subset of early-stage idiopathic PD patients which is mitigated by LRRK2 kinase inhibition, supporting a role for aberrant LRRK2 activity in idiopathic PD. Centrosomal defects are detected in R1441G-LRRK2 and G2019S-LRRK2 PD patients and in non-manifesting LRRK2 mutation carriers, indicating that they acumulate prior to a clinical PD diagnosis. They are present in immortalized cells as well as in primary lymphocytes from peripheral blood. These findings indicate that analysis of centrosomal defects as a blood-based patient stratification biomarker may help nominate PD patients who will benefit from LRRK2-related therapeutics. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.09.536178v1?rss=1 Authors: Wang, S., Sivadasan Bindu, D., Tan, C. X., Sakers, K., Takano, T., Rodriguez Salazar, M. P., Dimond, K., Soderling, S. H., La Spada, A. R., Eroglu, C. Abstract: Astrocytes tightly control neuronal connectivity and function in the brain through direct contact with synapses. These glial cells become reactive during disease pathogenesis including Parkinson's disease (PD). However, it remains unknown if astrocyte dysfunction is an initiating factor of PD pathogenesis and whether astrocytes can be targeted to stop or reverse the synaptic dysfunction seen in PD. Using in vitro and in vivo methods, we found that the PD-linked gene Lrrk2 controls astrocyte morphology via regulating the phosphorylation of ERM proteins (Ezrin, Radixin, and Moesin), a structural component of the perisynaptic astrocyte processes. ERM phosphorylation is robustly elevated both in mice and humans carrying the LRRK2 G2019S Parkinsonism mutation. Importantly, the reduction of the ERM phosphorylation, specifically in the LRRK2 G2019S in adult astrocytes, is sufficient to restore excitatory synapse number and function deficits in the LRRK2 G2019S knock-in mouse cortex. These results show a role for Lrrk2 in controlling astrocyte morphogenesis and synaptogenic function and reveal that early astrocyte dysfunction in PD could be causal to disruptions in cortical excitatory synaptic connectivity. The astrocytic dysfunction can be corrected by dampening ERM phosphorylation, pinpointing astrocytes as critical cellular targets for PD therapeutics. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.03.535418v1?rss=1 Authors: Pajarillo, E., Kim, S., Digman, A., Dutton, M., Son, D.-S., Aschner, M., Lee, E. Abstract: Chronic exposure to manganese (Mn) can lead to manganism, a neurological disorder sharing symptoms with those of Parkinson's disease (PD). Although the mechanisms of Mn toxicity are not fully understood, studies have shown that Mn increased the expression and activity of leucine-rich repeat kinase 2 (LRRK2), leading to inflammation and toxicity in microglia. LRRK2 G2019S mutation is the most common LRRK2 mutant associated with genetic PD and exhibits elevated LRRK2 kinase activity. Thus, we investigated whether Mn-increased microglial LRRK2 kinase function is responsible for Mn-induced toxicity and if it is exacerbated in G2019S using WT and LRRK2 G2019S knock-in mice as well as BV2 microglia cells. Results showed that Mn (MnCl2 30 mg/kg, nostril instillation, daily for 3 weeks) caused motor deficits, cognitive impairments, and dopaminergic dysfunction in WT mice, which were exacerbated in G2019S mice. Mn increased proapoptotic Bax, NLRP3 inflammasome, and inflammatory cytokines IL-1{beta} and TNF- in the striatum and midbrain of WT mice, which were exacerbated in G2019S mice. In addition, BV2 cells were transfected with either human LRRK2 WT or G2019S followed by exposure to Mn (250 uM) to compare Mn toxicity in two genotypes and gain more mechanistic insights. Results showed that Mn increased TNF-, IL-1{beta}, and NLRP3 inflammasome activation in BV2 cells expressing WT LRRK2, which was exacerbated in G2019S-expressing cells, while pharmacological inhibition of LRRK2 mitigated these toxicities in both genotypes. Moreover, the media from Mn-treated BV2 microglia expressing G2019S caused greater toxicity to CAD neuronal cells compared to media from microglia expressing WT. Mn-LRRK2 activated RAB10, an LRRK2 substrate, which was exacerbated in G2019S, and played a critical role in LRRK2-mediated Mn toxicity by dysregulating the autophagy-lysosome pathway, and NLRP3 inflammasome in microglia. Taken together, our findings suggest that microglial LRRK2 via RAB10 plays a critical role in Mn-induced neuroinflammation, and inhibition of LRRK2 kinase activity can be a potential target to mitigate Mn's inflammatory neurotoxicity. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.03.31.535090v1?rss=1 Authors: Wetzel, A., Lei, S. H., Liu, T., Hughes, M. P., Peng, Y., McKay, T., Waddington, S. N., Granno, S., Rahim, A. A., Harvey, K. Abstract: Background: Parkinson`s disease (PD) is a progressive late-onset neurodegenerative disease leading to physical and cognitive decline. Mutations of leucine-rich repeat kinase 2 (LRRK2) are the most common genetic cause of PD. LRRK2 is a complex scaffolding protein with known regulatory roles in multiple molecular pathways. Two prominent examples of LRRK2-modulated pathways are Wingless/Int (Wnt) and nuclear factor of activated T-cells (NFAT) signaling. Both are well described key regulators of immune and nervous system development as well as maturation. The aim of this study was to establish the physiological and pathogenic role of LRRK2 in Wnt and NFAT signaling in the brain, as well as the potential contribution of the non-canonical Wnt/Calcium pathway. Methods: In vivo cerebral Wnt and NFATc1 signaling activity was quantified in LRRK2 G2019S mutant knock-in (KI) and LRRK2 knockout (KO) male and female mice with repeated measures over 28 weeks, employing lentiviral luciferase biosensors, and analyzed using a mixed-effect model. To establish spatial resolution, we investigated tissues, and primary neuronal cell cultures from different brain regions combining luciferase signaling activity, immunohistochemistry, qPCR and western blot assays. Results were analyzed by unpaired t-test with Welch`s correction or 2-way ANOVA with post hoc corrections. Results: In vivo Wnt signaling activity in LRRK2 KO and LRRK2 G2019S KI mice was increased significantly ~3-fold, with a more pronounced effect in males (~4-fold) than females (~2-fold). NFATc1 signaling was reduced ~0.5-fold in LRRK2 G2019S KI mice. Brain tissue analysis showed region-specific expression changes in Wnt and NFAT signaling components. These effects were predominantly observed at the protein level in the striatum and cerebral cortex of LRRK2 KI mice. Primary neuronal cell culture analysis showed significant genotype-dependent alterations in Wnt and NFATc1 signaling under basal and stimulated conditions. Wnt and NFATc1 signaling was primarily dysregulated in cortical and hippocampal neurons respectively. Conclusions: Our study further built on knowledge of LRRK2 as a Wnt and NFAT signaling protein. We identified complex changes in neuronal models of LRRK2 PD, suggesting a role for mutant LRRK2 in the dysregulation of NFAT, and canonical and non-canonical Wnt signaling. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.26.530068v1?rss=1 Authors: Nadiminti, S. S. P., Dixit, S. B., Ratnakaran, N., Hegde, S., Swords, S., Grant, B. D., Koushika, S. P. Abstract: Synaptic vesicle proteins (SVps) are thought to travel in heterogeneous carriers dependent on the motor UNC-104/KIF1A. In C. elegans neurons, we found that some SVps are transported along with lysosomal proteins by the motor UNC-104/KIF1A. LRK-1/LRRK2 and the clathrin adaptor protein complex AP-3 are critical for the separation of lysosomal proteins from SVp transport carriers. In lrk-1 mutants, both SVp carriers and SVp carriers containing lysosomal proteins are independent of UNC-104, suggesting that LRK-1 plays a key role in ensuring UNC-104-dependent transport of SVps. Additionally, LRK-1 likely acts upstream of the AP-3 complex and regulates the membrane localization of AP-3. The action of AP-3 is necessary for the active zone protein SYD-2/Liprin- to facilitate the transport of SVp carriers. In the absence of the AP-3 complex, SYD-2/Liprin- acts with UNC-104 to instead facilitate the transport of SVp carriers containing lysosomal proteins. We further show that the mistrafficking of SVps into the dendrite in lrk-1 and apb-3 mutants depends on SYD-2, likely by regulating the recruitment of the AP-1/UNC-101. We propose that SYD-2 acts in concert with both the AP-1 and AP-3 complexes to ensure polarized trafficking of SVps. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.21.529466v1?rss=1 Authors: Bondar, V. V., Wang, X., Davis, O. B., Maloney, M. T., Agam, M., Chin, M. Y., Ho, A. C.-N., Joy, D., Lewcock, J. W., Di Paolo, G., Thorne, R. G., Sweeney, Z. K., Henry, A. G. Abstract: Leucine-rich repeat kinase 2 (LRRK2) variants associated with Parkinson's disease (PD) and Crohn's disease lead to increased phosphorylation of its Rab substrates. While it has been recently shown that perturbations in cellular homeostasis including lysosomal damage and stress can increase LRRK2 activity and localization to lysosomes, the molecular mechanisms by which LRRK2 activity is regulated have remained poorly defined. We performed a targeted siRNA screen to identify regulators of LRRK2 activity and identified Rab12 as a novel modulator of LRRK2-dependent phosphorylation of one of its substrates, Rab10. Using a combination of imaging and immunopurification methods to isolate lysosomes, we demonstrated that Rab12 is actively recruited to damaged lysosomes and leads to a local and LRRK2-dependent increase in Rab10 phosphorylation. PD-linked variants, including LRRK2 R1441G and VPS35 D620N, lead to increased recruitment of LRRK2 to the lysosome and a local elevation in lysosomal levels of pT73 Rab10. Together, these data suggest a conserved mechanism by which Rab12, in response to damage or expression of PD-associated variants, promotes the recruitment of LRRK2 and phosphorylation of its Rab substrate(s) at the lysosome. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.02.15.528749v1?rss=1 Authors: Maxson, M. E., Huynh, K., Grinstein, S. Abstract: While it has been known for decades that luminal acidification is required for normal traffic along the endocytic pathway, the precise underlying mechanism(s) remain unknown. We found that dissipation of the endomembrane pH gradient resulted in acute formation of large Rab5- or Rab7-positive vacuoles. Vacuole formation was associated with and required hyperactivation of the Rabs, which was attributable to impaired GTPase activity, despite normal recruitment of cognate GAPs. Surprisingly, LRRK2 -a kinase linked to Parkinsons disease-was recruited to endomembranes and markedly activated upon dissipation of luminal acidification. LRRK2 phosphorylated Rab GTPases, rendering them insensitive to deactivation. Importantly, genetic deletion of LRRK2 prevented the {Delta}pH-induced vacuolation, implying that the kinase is required to modulate vesicular traffic. We propose that by dictating the state of activation of LRRK2 and in turn that of Rab GTPases, the development of a progressive luminal acidification serves as a timing device to control endocytic maturation. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.01.27.524249v1?rss=1 Authors: Kelly, K., Lewis, P., Plun-Favreau, H., Manzoni, C. Abstract: Whilst the majority of PD cases are sporadic, much of our understanding of the pathophysiological basis of disease can be traced back to the study of rare, monogenic forms of disease. In the past decade, the availability of Genome-Wide Association Studies (GWAS) has facilitated a shift in focus, toward identifying common risk variants conferring increased risk of developing PD across the population. A recent mitophagy screening assay of GWAS candidates has functionally implicated the non-specific lethal (NSL) complex in the regulation of PINK1-mitophagy. Here, a bioinformatics approach has been taken to investigate the proteome of the NSL complex, to unpick its relevance to PD progression. The mitochondrial NSL interactome has been built, mining 3 separate repositories: PINOT, HIPPIE and MIST, for curated, literature-derived protein-protein interaction (PPI) data. We built; i) the 'mitochondrial interactome', applying gene-set enrichment analysis (GSEA) to explore the relevance of the NSL mitochondrial interactome to PD and, ii) the 'PD-oriented interactome' to uncover biological pathways underpinning the NSL /PD association. In this study, we find the mitochondrial NSL interactome to be significantly enriched for the protein products of PD associated genes, including the Mendelian PD genes LRRK2 and VPS35. Additionally, the PD associated interactome is enriched for mitochondrial processes; "mitochondrial cell death", "mitochondrial protein localisation", "membrane protein localisation" and "mitochondrial transport". Our data points to NSL complex members OGT and WDR5 as key drivers of this increased PD association. These findings strengthen a role for mitochondrial quality control in both familial and sporadic disease. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.12.19.521070v1?rss=1 Authors: Maloney, M. T., Wang, X., Ghosh, R., Andrews, S. V., Maciuca, R., Masoud, S. T., Caprioli, R. M., Chen, J., Chiu, C.-L., Davis, S. S., Ho, A. C.-N., Nguyen, H. N., Propson, N. E., Reyzer, M. L., Davis, O. B., Deen, M. C., Zhu, S., Di Paolo, G., Vocadlo, D. J., Estrada, A. A., de Vicente, J., Lewcock, J. W., Arguello, A., Suh, J. H., Huntwork-Rodriguez, S., Henry, A. G. Abstract: Lysosomal dysfunction is a hallmark of Parkinson's disease (PD), and variants in several PD-associated genes, including LRRK2, perturb lysosomal homeostasis. Based on this, LRRK2 kinase inhibition is being explored as a therapeutic approach for the treatment of PD. LRRK2 inhibitors reduce levels of BMP, an endolysosomal lipid involved in glycosphingolipid (GSL) catabolism, in urine from preclinical models and clinical subjects, however, the mechanisms by which LRRK2 regulates BMP and the functional significance of this change to disease are undefined. We establish that LRRK2 regulates secretion of BMP- and GSL-containing vesicles from kidney into urine and modulates BMP and GSL levels in the brain. BMP accumulates within lysosomes as a secondary response to LRRK2's effects on the activity of glucocerebrosidase (GCase), a PD-linked enzyme involved in GSL catabolism. Alterations in BMP and GCase substrate turnover are observed in CSF from LRRK2-PD patients, highlighting the relevance of LRRK2-dependent lysosomal dysfunction in disease. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.12.19.521070v1?rss=1 Authors: Maloney, M. T., Wang, X., Ghosh, R., Andrews, S. V., Maciuca, R., Masoud, S. T., Caprioli, R. M., Chen, J., Chiu, C.-L., Davis, S. S., Ho, A. C.-N., Nguyen, H. N., Propson, N. E., Reyzer, M. L., Davis, O. B., Deen, M. C., Zhu, S., Di Paolo, G., Vocadlo, D. J., Estrada, A. A., de Vicente, J., Lewcock, J. W., Arguello, A., Suh, J. H., Huntwork-Rodriguez, S., Henry, A. G. Abstract: Lysosomal dysfunction is a hallmark of Parkinson's disease (PD), and variants in several PD-associated genes, including LRRK2, perturb lysosomal homeostasis. Based on this, LRRK2 kinase inhibition is being explored as a therapeutic approach for the treatment of PD. LRRK2 inhibitors reduce levels of BMP, an endolysosomal lipid involved in glycosphingolipid (GSL) catabolism, in urine from preclinical models and clinical subjects, however, the mechanisms by which LRRK2 regulates BMP and the functional significance of this change to disease are undefined. We establish that LRRK2 regulates secretion of BMP- and GSL-containing vesicles from kidney into urine and modulates BMP and GSL levels in the brain. BMP accumulates within lysosomes as a secondary response to LRRK2's effects on the activity of glucocerebrosidase (GCase), a PD-linked enzyme involved in GSL catabolism. Alterations in BMP and GCase substrate turnover are observed in CSF from LRRK2-PD patients, highlighting the relevance of LRRK2-dependent lysosomal dysfunction in disease. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.12.17.520834v1?rss=1 Authors: Yadavalli, N., Ferguson, S. Abstract: Variants in leucine rich repeat kinase 2 (LRRK2) that increase kinase activity confer risk for sporadic and familial forms of Parkinson's disease. However, LRRK2-dependent cellular processes responsible for disease risk remain uncertain. Here we show that LRRK2 negatively regulates lysosome degradative activity in macrophages and microglia via a transcriptional mechanism. Depletion of LRRK2 and inhibition of LRRK2 kinase activity both enhance lysosomal proteolytic activity and increase the expression of multiple lysosomal hydrolases. Conversely, the kinase hyperactive LRRK2 G2019S Parkinson's disease mutant suppresses lysosomal degradative activity and gene expression. We identified transcription factor E3 (TFE3) as a mediator of LRRK2-dependent control of lysosomal gene expression. LRRK2 negatively regulates both the abundance and nuclear localization of TFE3 and LRRK2-dependent changes in lysosome protein expression require TFE3. These discoveries define a mechanism for LRRK2-dependent control of lysosomes and support a model wherein LRRK2 hyperactivity increases Parkinson's disease risk by suppressing lysosome degradative activity. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.12.06.519338v1?rss=1 Authors: Stickley, L., Nagoshi, E. Abstract: Parkinson's disease (PD) is the second most common neurodegenerative disorder, afflicting over 1% of the population of age 60 years and above. The loss of dopaminergic (DA) neurons is the substantia nigra pars compacta (SNpc) is the primary cause of its characteristic motor symptoms. Studies using Drosophila melanogaster and other model systems have provided much insight into the pathogenesis of PD. However, little is known why certain cell types are selectively susceptible to degeneration in PD. Here we describe an approach to identify vulnerable subpopulations of neurons in the genetic background linked to PD in Drosophila, using the split-GAL4 divers that enable genetic manipulation of a small number of defined cell population. We identify a subtype of DA neurons selectively vulnerable in the model of the leucine-rich repeat kinase 2 (LRRK2)-linked familial PD, demonstrating the utility of this approach. We also show an unexpected caveat of the split-GAL4 system in aging-related research: the age-dependent increase in the number of GAL4-labeled cells. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.30.517979v1?rss=1 Authors: Pena, N., Gonzalez-Hunt, C., Qi, R., Barlow, C., Shanks, N. F., Carlisle, H., Sanders, L. H. Abstract: Pathogenic mutations in LRRK2 cause Parkinson's disease (PD). The G2019S variant is the most common, which results in abnormally high kinase activity. Compounds that target LRRK2 kinase activity are currently being developed and tested in clinical trials. We recently found that G2019S LRRK2 causes mitochondrial DNA (mtDNA) damage and treatment with multiple classes of LRRK2 kinase inhibitors at concentrations associated with dephosphorylation of LRRK2 reversed mtDNA damage to healthy control levels. Because maintaining the normal function of LRRK2 in heterozygous G2019S LRRK2 carriers while specifically targeting the G2019S LRRK2 activity could have an advantageous safety profile, we explored the efficacy of a G2019S mutant selective LRRK2 inhibitor to reverse mtDNA damage in G2019S LRRK2 models and patient cells relative to non-selective LRRK2 inhibitors. Potency of LRRK2 kinase inhibition by EB-42168, a G2019S mutant LRRK2 kinase inhibitor, and MLi-2, a nonselective inhibitor, was determined by measuring phosphorylation of LRRK2 at Ser935 and/or Ser1292 using quantitative western immunoblot analysis. The Mito DNADX assay, a novel system that allows for the accurate real-time quantification of mtDNA damage in a 96-well platform, was performed in parallel. We confirmed that EB-42168 selectively inhibits LRRK2 phosphorylation on G2019S LRRK2 relative to wild-type LRRK2. On the other hand, MLi-2 was equipotent for wild-type and G2019S LRRK2. Acute treatment with EB-42168 inhibited LRRK2 phosphorylation and also restored mtDNA damage to healthy control levels. Precision medicine is a common approach in modern day cancer research that is not yet routinely applied to neurodegenerative diseases. Abrogation of mtDNA damage with mutant selective tool inhibitor EB-42168 demonstrates the promise of a precision medicine approach for LRRK2 G2019S PD. Levels of mtDNA damage may serve as a potential pharmacodynamic biomarker of altered kinase activity that could be useful for small molecule development and clinical trials. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.22.517583v1?rss=1 Authors: Fasimoye, R., Dong, W., Nirujogi, R. S., Rawat, E. S., Iguchi, M., Nyame, K., Phung, T. K., Bagnoli, E., Prescott, A. R., Alessi, D. R., Abu-remaileh, M. Abstract: The Golgi is a membrane-bound organelle that is essential for protein and lipid biosynthesis. It represents a central trafficking hub that sorts proteins and lipids to various destinations or for secretion from the cell. The Golgi has emerged as a docking platform for cellular signalling pathways including LRRK2 kinase whose deregulation leads to Parkinson disease. Golgi dysfunction is associated with a broad spectrum of diseases including cancer, neurodegeneration, and cardiovascular diseases. To allow the study of the Golgi at high resolution, we report a rapid immunoprecipitation technique (Golgi-IP) to isolate intact Golgi mini-stacks for subsequent analysis of their content. By fusing the Golgi resident protein TMEM115 to three tandem HA epitopes (GolgiTAG), we purified the Golgi using Golgi-IP with minimal contamination from other compartments. We then established an analysis pipeline using liquid chromatography coupled with mass spectrometry to characterize the human Golgi proteome, metabolome and lipidome. Subcellular proteomics confirmed known Golgi proteins and identified novel ones. Metabolite profiling established the first known human Golgi metabolome and revealed the selective enrichment of uridine-diphosphate (UDP) sugars and their derivatives, which is consistent with their roles in protein and lipid glycosylation. Furthermore, targeted metabolomics validated SLC35A2 as the subcellular transporter for UDP-hexose. Finally, lipidomics analysis showed that phospholipids including phosphatidylcholine, phosphatidylinositol and phosphatidylserine are the most abundant Golgi lipids and that glycosphingolipids are enriched in this compartment. Altogether, our work establishes a comprehensive molecular map of the human Golgi and provides a powerful method to study the Golgi with high precision in health and disease states. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.14.516471v1?rss=1 Authors: Dou, D., Smith, E. M., Evans, C. S., Boecker, C. A., Holzbaur, E. L. F. Abstract: Gain-of-function mutations in the LRRK2 gene cause Parkinson's disease (PD), increasing phosphorylation of RAB GTPases through hyperactive kinase activity. We found that LRRK2-hyperphosphorylated RABs disrupt the axonal transport of autophagosomes by perturbing the coordinated regulation of cytoplasmic dynein and kinesin motors. In iPSC-derived human neurons, knock-in of the strongly-hyperactive LRRK2-p.R1441H mutation caused striking impairments in autophagosome transport, inducing frequent directional reversals and pauses. Knock-out of the opposing Protein Phosphatase 1H (PPM1H) phenocopied the effect of hyperactive LRRK2. Overexpression of ADP-ribosylation factor 6 (ARF6), a GTPase that acts as a switch for selective activation of dynein or kinesin, attenuated transport defects in both p.R1441H knock-in and PPM1H knock-out neurons. Together, these findings support a model where a regulatory imbalance between LRRK2-hyperphosphorylated RABs and ARF6 induces an unproductive "tug-of-war" between dynein and kinesin, disrupting processive autophagosome transport. This disruption may contribute to PD pathogenesis by impairing the essential homeostatic functions of axonal autophagy. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.11.516171v1?rss=1 Authors: Leyns, C. E. G., Prigent, A., Beezhold, B., Yao, L., Hatcher, N., Tao, P., Kang, J., Suh, E., Van Deerlin, V. M., Trojanowski, J. Q., Lee, V. M. Y., Kennedy, M., Fell, M., Henderson, M. X. Abstract: Parkinson's disease (PD) and dementia with Lewy bodies (DLB) are progressive neurodegenerative diseases characterized by the accumulation of misfolded -synuclein in the form of Lewy pathology. While most cases are sporadic, there are rare genetic mutations that cause disease and more common variants that increase incidence of disease. The most prominent genetic mutations for PD and DLB are in the GBA1 and LRRK2 genes. GBA1 mutations are associated with decreased glucocerebrosidase activity and lysosomal accumulation of its lipid substrates, glucosylceramide and glucosylsphingosine. Previous studies have shown a link between this enzyme and lipids even in sporadic PD. However, it is unclear how the protein pathologies of disease are related to enzyme activity and glycosphingolipid levels. To address this gap in knowledge, we examined quantitative protein pathology, glucocerebrosidase activity and lipid substrates in parallel from 4 regions of 91 brains with no neurological disease, idiopathic, GBA1-linked, or LRRK2-linked PD and DLB. We find that several biomarkers are altered with respect to mutation and disease severity. We found mild association of glucocerebrosidase activity with disease, but a strong association of glucosylsphingosine with 8-synuclein pathology, irrespective of genetic mutation. This association suggests that Lewy pathology precipitates changes in lipid levels related to disease severity. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.10.31.514622v1?rss=1 Authors: Tombesi, G., Chen, C., Favetta, G., Plotegher, N., Sevegnani, M., Marte, A., Battisti, I., Civiero, L., Onofri, F., Piccoli, G., Arrigoni, G., Manzoni, C., Parisiadou, L., Greggio, E. Abstract: Dendritic spines, small protrusions of the dendrites, constitute the postsynaptic compartment of excitatory synapses. Filamentous actin is the major cytoskeletal constituent of dendritic spines, whose dynamic nature allows them to plastically remodel their shape and volume in response to stimuli. Notably, dendritic spine abnormalities are linked to a number of neurological and neurodegenerative disorders. Here, we show that the Parkinson disease (PD)-associated kinase LRRK2 participates in spine remodeling processing by binding a panel of actin-related proteins enriched in postsynaptic compartments. Phosphorylation of LRRK2 Ser935, which controls LRRK2 subcellular localization, rapidly increases upon brain-derived neurotrophic factor (BDNF) stimulation of differentiated SH-SY5Y cells and primary mouse neurons. Affinity-purification coupled with mass spectrometry (AP-MS/MS) analysis revealed that LRRK2 interactome is significantly reshaped upon BDNF stimulation, with an interconnected network of actin cytoskeleton-associated proteins increasing their binding to LRRK2. Accordingly, Lrrk2 knockout primary neurons exhibit impaired response to BDNF-induced spinogenesis and TrkB signaling. In vivo, one-month old Lrrk2 knockout mice exhibit defects in spine maturation, a phenotype that disappears with age. Finally, by comparing the phosphoproteomes of Lrrk2 wild-type versus Lrrk2 G2019S PD mutant synaptosomes, we found that the differentially phosphorylated proteins are enriched in categories related to postsynaptic structural organization. Taken together, our study discloses a critical function of LRRK2 in shaping dendritic spine morphology during development and defines a mechanistic role of the kinase in postsynaptic actin-cytoskeletal dynamics. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.09.01.505977v1?rss=1 Authors: Giachino, C., Tirolo, C., Caniglia, S., Serapide, M. F., L'Episcopo, F., Bertoli, F., Giuliano, C., Mearelli, M., Jakobi, M., Schneiderhan-Marra, N., Deleidi, M., Marchetti, B. Abstract: Background: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most frequent cause of familial Parkinson's disease (PD). The incomplete penetrance of LRRK2 mutations suggest that additional hits are required for disease onset. We hypothesized that chronic low-grade inflammation interacts with LRRK2 G2019S, the most frequent PD-associated mutation, to activate peripheral and central immune reactions and drive age-dependent neurodegeneration. Methods and Results: We exposed wild-type and LRRK2 G2019S mice to a low chronic dose of lipopolysaccharide, and we performed a longitudinal analysis of central and peripheral immune reactions and neurodegeneration. Low-dose inflammation triggered nigrostriatal degeneration, macrophage/monocyte brain infiltration, and astro-/microgliosis. LRRK2 G2019S mice showed an early dysregulation of peripheral cytokines, increased CD4+ T-cell infiltration and -synuclein aggregation in the colon. Interestingly, peripheral immune activation and colonic -synuclein aggregation precede astro-/microgliosis and neurodegeneration. Conclusions: Our study suggests an early role of the peripheral immune system and the gut in LRRK2 PD and provides a novel model to study early therapeutic immune targets and biomarkers. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.08.23.504918v1?rss=1 Authors: Pons-Espinal, M., Blasco-Agell, L., Fernandez-Carasa, I., di Domenico, A., Richaud, Y., Mosquera, J. L., Marruecos, L., Espinosa, L., Garrido, A., Tolosa, E., Edel, M. J., Juan Otero, M., Ferrer, I., Raya, A., Consiglio, A. Abstract: Parkinson's disease (PD) is associated with premature death of dopamine-producing neurons in the brain. Previous studies have shown that astrocytes of PD patients may contribute to neuronal degeneration by mechanisms involving both direct cell-to-cell contact and transfer of soluble molecules. Since it has been proposed that PD patients exhibit an overall pro-inflammatory state, and since astrocytes are key mediators of the inflammation response in the brain, here we sought to address whether astrocyte-mediated inflammatory signaling could contribute to PD neuropathology. For this purpose, we generated astrocytes from induced pluripotent stem cells (iPSCs) representing PD patients and healthy controls. Transcriptomic analyses identified a unique inflammatory gene expression signature in PD astrocytes compared to controls. In particular, the pro-inflammatory cytokine IL-6 was found to be highly expressed and released by PD astrocytes, and to induce toxicity in dopamine neurons. Mechanistically, neuronal cell death was mediated by IL-6 signaling via IL-6 receptor (IL-6R) expressed in human PD neurons, leading to downstream activation of STAT3. Importantly, astrocyte-induced cell death in PD disease midbrain neurons could be prevented by blocking IL6R-mediated signaling using clinically available antibodies. Moreover, examination of postmortem tissue brain of early-stage PD patients uncovered increased numbers of dopamine neurons overexpressing IL-6R and of reactive astrocytes overexpressing IL-6, compared to healthy brains. Our findings highlight the potential role of astrocyte-mediated inflammatory signaling in neuronal loss in PD, and open the way for new therapies based on IL-6 immunomodulation for preventing PD pathogenesis. Copy rights belong to original authors. Visit the link for more info Podcast created by PaperPlayer

What is the role of genetics in Parkinson's disease? From the impact of variants in the LRRK2 gene, to the need to expand PD research in diverse populations to aid the development of new medicines, this week's guests, Dr Ignacio Mata and Dr James Beck, talk to Patrick about the history, and future, of precision medicine development in Parkinson's disease.

What is the role of genetics in Parkinson's disease? From the impact of variants in the LRRK2 gene, to the need to expand PD research in diverse populations to aid the development of new medicines, this week's guests, Dr Ignacio Mata and Dr James Beck, talk to Patrick about the history, and future, of precision medicine development in Parkinson's disease.

Dr. Bahareh (Spring) Behrouz, PhD, is the CEO of Vincere Biosciences Inc (https://vincerebio.com/), a biotech company focused on developing novel, small molecule therapeutics targeting mitochondrial pathways and the improvement of mitochondrial quality. Dr. Behrouz is also the CEO of NeuroInitiative, LLC (https://www.neuroinitiative.com/), a computational biology company she co-founded in 2014, which develops simulations of disease using their patented software platform. A core focus of her research at NeuroInitiative is on the elucidation of complex, converging pathways that contribute to the pathogenesis of Parkinson's disease (PD), a neuro-degenerative brain disorder which dramatically effects movement, which nearly one million people in the U.S. are living with, and 10 million patients worldwide. Dr. Behrouz received her graduate training at Michigan State University in the laboratory of Dr. John Goudreau and studied differential susceptibility of dopaminergic neuron sub-types in models of PD. She completed her post-doctoral training in the laboratory of Dr. Matthew Farrer at the Mayo Clinic in Jacksonville, where she primarily focused on in-vivo and primary culture models of LRRK2-mediated pathogenesis and was part of the team that discovered a new pathogenic mutation in VPS35

How can precision medicine techniques be used to develop potential new treatments for genetic Parkinson's disease? In the latest episode of our Precision Pioneers miniseries, Patrick speaks to Dr Carrolee Barlow, Chief Medical Officer at ESCAPE Bio, about the challenges of accessing genetic testing for Parkinson's patients, how genetically guided treatments could help patients with the LRRK2 gene, and how new technologies such as wearable devices could help catch Parkinson's cases at an earlier stage.

How can precision medicine techniques be used to develop potential new treatments for genetic Parkinson's disease? In the latest episode of our Precision Pioneers miniseries, Patrick speaks to Dr Carrolee Barlow, Chief Medical Officer at ESCAPE Bio, about the challenges of accessing genetic testing for Parkinson's patients, how genetically guided treatments could help patients with the LRRK2 gene, and how new technologies such as wearable devices could help catch Parkinson's cases at an earlier stage.

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson's disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson's disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

Hear how a team of interdisciplinary experts solved the structure of LRRK2, a gene found to be mutated in Parkinson’s disease, and how their discovery is guiding the way for new targeted therapeutics. Series: "Innovations Shaping the Future of Parkinson's Disease Treatment " [Health and Medicine] [Show ID: 37039]

In this episode we discuss the genetic connection to Parkinson's. It doesn't matter if you know you have a genetic mutual, if you know you don't have one or you don't know and don't want to know, you will learn a lot about how the research into the genetic mutations linked to PD is leading to science better understanding of the origins of the disease and eventually a cure. We talk to a leading researcher at NYU about the connection. Also, we hear from a family who has a deep connection to the LRRK2 mutation and what that has meant to them.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.21.348144v1?rss=1 Authors: Obergasteiger, J., Castonguay, A.-M., Frapporti, G., Lobbestael, E., Baekelandt, V., Hicks, A., Pramstaller, P., Gravel, C., Corti, C., Levesque, M., Volta, M. Abstract: In Parkinson's disease (PD) misfolded alpha-synuclein (aSyn) accumulates in the substantia nigra, where dopaminergic neurons are progressively lost. The mechanisms underlying aSyn pathology are still unclear but hypothesized to involve the autophagy lysosome pathways (ALP). LRRK2 mutations are a major cause of familial and sporadic PD, hyperactivate kinase activity and its pharmacological inhibition reduces pS129-aSyn inclusions. We observed selective downregulation of the novel PD risk factor RIT2 in G2019S-LRRK2 expressing cells. Here we studied whether RIT2 could modulate LRRK2 kinase activity. RIT2 overexpression in G2019S-LRRK2 cells rescued ALP abnormalities and diminished aSyn inclusions. In vivo, viral mediated overexpression of RIT2 operated neuroprotection against AAV-A53T-aSyn. Furthermore, RIT2 overexpression prevented the A53T-aSyn-dependent increase of LRRK2 kinase activity in vivo. Our data indicate that RIT2 inhibits overactive LRRK2 to ameliorate ALP impairment and counteract aSyn aggregation and related deficits. Targeting RIT2 could represent a novel strategy to combat neuropathology in familial and idiopathic PD. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.13.337857v1?rss=1 Authors: Henderson, M., Cornblath, E. J., Li, H. L., Changolkar, L., Zhang, B., Brown, H. J., Gathagan, R. J., Olufemi, M. F., Bassett, D. S., Trojanowski, J. Q., Lee, V. M. Y. Abstract: Tau pathology is a diagnostic feature of Alzheimer's disease (AD) but is also a prominent feature of Parkinson's disease (PD), including genetic forms of PD with mutations in leucine-rich repeat kinase 2 (LRRK2). In both diseases, tau pathology is progressive and correlates with cognitive decline. Neuropathological staging studies in humans and mouse models have suggested that tau spreads through the brain, but it is unclear how neuroanatomical connections, spatial proximity, and regional vulnerability contribute to pathology spread. Further, it is unknown how mutations in the LRRK2 gene may modulate susceptibility to tau pathology's initiation or spread. In this study, we used seed-based models of tauopathy to capture spatiotemporal patterns of pathology in mice. Following the injection of AD brain-derived tau into the brains of non-transgenic mice, tau pathology spreads progressively through the brain in a spatiotemporal pattern that is well-explained by anatomical connectivity. We validated and compared network models based on diffusion along anatomical connections to predict tau spread, estimate regional vulnerability to tau pathology, and investigate gene expression patterns related to regional vulnerability. We further investigated tau pathology spread in mice harboring a mutation in LRRK2 and found that while tau pathology spread is still constrained by anatomical connectivity, it spreads preferentially in a retrograde direction to regions that are otherwise resilient in wildtype mice. This study provides a quantitative demonstration that tau pathology spreads along anatomical connections, explores the kinetics of this spread, and provides a platform for investigating the effect of genetic risk factors and treatments on the progression of tauopathies. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.28.316992v1?rss=1 Authors: Fellgett, A., Middleton, C. A., Munns, J., Ugbode, C., Jaciuch, D., Wilson, L., Chawla, S., Elliott, C. Abstract: Abstract Background: Inherited mutations in the LRRK2 protein are the most common known cause of Parkinson's, but the mechanisms by which increased kinase activity of mutant LRRK2 leads to pathological events remain to be determined. In vitro assays (heterologous cell culture, phospho-protein mass spectrometry) suggest that several Rab proteins might be directly phosphorylated by LRRK2-G2019S. Which Rabs interact with LRRK2 in dopaminergic neurons to facilitate normal and pathological physiological responses remains to be determined. An in vivo screen of Rab expression in dopaminergic neurons in young adult Drosophila demonstrated a strong genetic interaction between LRRK2-G2019S and Rab10. We now ask if Rab10 is required for LRRK2-induced physiological responses in DA neurons. Methods: LRRK2-G2019S was expressed in Drosophila dopaminergic neurons and the effects of Rab10 depletion on Proboscis Extension, vision, circadian activity pattern and courtship memory determined in aged flies. Results: Rab10 loss-of-function rescued bradykinesia of the Proboscis Extension Response (PER) and visual defects of aged flies expressing LRRK2-G2019S in DA neurons. Rab10 knock-down however, did not rescue the marked sleep phenotype which results from dopaminergic expression of LRRK2-G2019S. Courtship memory is not affected by LRRK2 expression, but is markedly improved by Rab10 depletion. Anatomically, both LRRK2-G2019S and Rab10 are seen in the cytoplasm and at the synaptic endings of dopaminergic neurons. Conclusions: We conclude that, in Drosophila dopaminergic neurons, Rab10 is involved differentially in LRRK2-induced behavioral deficits. Therefore, variations in Rab expression may contribute to susceptibility of dopaminergic neurons to neurodegeneration seen in people with Parkinson's. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.11.246363v1?rss=1 Authors: Evans, L. D., Strano, A., Campbell, A., Karakoc, E., Iorio, F., Bassett, A. R., Livesey, F. J. Abstract: Pathological protein aggregation in Alzheimers disease and other dementias is proposed to spread through the nervous system by a process of intercellular transfer of pathogenic forms of tau protein. Defining the cellular mechanisms of tau entry to human neurons is essential for understanding dementia pathogenesis and the rational design of disease-modifying therapeutics. Using whole genome CRISPR knockout screens in human iPSC-derived excitatory neurons, the primary cell type affected in these diseases, we identified genes and pathways required specifically for uptake of monomeric and aggregated tau. Monomeric and aggregated tau are both taken up by human neurons by receptor-mediated endocytosis, with the low-density lipoprotein LRP1 a significant surface receptor for both forms of tau. Perturbations of the endolysosome and autophagy systems at many levels, and specifically endosome sorting and receptor recycling, greatly reduced tau uptake. Of particular therapeutic interest is that loss of function of the endocytosis and autophagy regulator LRRK2, as well as acute inhibition of its kinase activity, reduced neuronal uptake of monomeric and aggregated tau. Kinase-activating mutations in LRRK2 are a cause of Parkinsons disease accompanied by neuronal tau aggregation, suggesting that LRRK2 mediates tau spreading in vivo and that LRRK2 inhibition has the potential to inhibit interneuronal spread of tau pathology, slowing disease progression. Overall, pathways for tau entry share significant similarity with those required for virus entry by receptor-mediated endocytosis, suggesting that tau spreading is a quasi-infectious process. Copy rights belong to original authors. Visit the link for more info

In this episode, we are talking with organizations well known for funding research in the Parkinson's field – including The Michael J Fox Foundation and The Parkinson's Foundation. We speak with the experts about the future in treating the symptoms, halting the progression and curing PD.  And, we will speak to a PD patient who has a fascinating story and readily participates in research. The more research participants we have, the faster the scientists can find answers to solving the PD puzzle and speed medication and device solutions to market helping us all. You don't want to miss this episode.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.06.190025v1?rss=1 Authors: Senchuk, M. M., Van Raamsdonk, J. M., Moore, D. J. Abstract: Background: Mutations in the leucine-rich repeat kinase 2 (LRRK2) gene are the most frequent cause of late-onset, familial Parkinson's disease (PD), and LRRK2 variants are associated with increased risk for sporadic PD. While advanced age represents the strongest risk factor for disease development, it remains unclear how different age-related pathways interact to regulate LRRK2-driven late-onset PD. Findings: In this study, we employ a C.elegans model expressing PD-linked G2019S LRRK2 to examine the interplay between age-related pathways and LRRK2-induced dopaminergic neurodegeneration. We find that multiple genetic pathways that regulate lifespan extension can provide robust neuroprotection against mutant LRRK2. However, the level of neuroprotection does not strictly correlate with the magnitude of lifespan extension, suggesting that lifespan can be experimentally dissociated from neuroprotection. Using tissue-specific RNAi, we demonstrate that lifespan-regulating pathways, including insulin/IGF-1 signaling, TOR, and mitochondrial respiration, can be directly manipulated in neurons to mediate neuroprotection. We extend this finding for AGE-1/PI3K, where pan-neuronal versus dopaminergic neuronal restoration of AGE-1 reveals both cell-autonomous and non-cell-autonomous neuroprotective mechanisms downstream of insulin signaling. Conclusions: Our data demonstrate the importance of distinct lifespan-regulating pathways in the pathogenesis of LRRK2-linked PD, and suggest that extended longevity is broadly neuroprotective via the actions of these pathways at least in part within neurons. This study further highlights the complex interplay that occurs between cells and tissues during organismal aging and disease manifestation. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.02.178574v1?rss=1 Authors: de Rus Jacquet, A., Tancredi, J. L., Lemire, A. L., DeSantis, M. C., Li, W.-P., O'Shea, E. K. Abstract: Astrocytes are essential cells of the central nervous system, characterized by dynamic relationships with neurons that range from functional metabolic interactions and regulation of neuronal firing activities, to the release of neurotrophic and neuroprotective factors. In Parkinson's disease (PD), dopaminergic neurons are progressively lost during the course of the disease, but the effects of PD on astrocytes and astrocyte-to-neuron communication remains largely unknown. This study focuses on the effects of the PD-related mutation LRRK2 G2019S in astrocytes, generated from patient-derived induced pluripotent stem cells. We report the alteration of extracellular vesicle (EV) biogenesis in astrocytes, and we identify the abnormal accumulation of key PD-related proteins within multi vesicular bodies (MVBs). We found that dopaminergic neurons internalize astrocyte-secreted EVs but LRRK2 G2019S EVs are abnormally enriched in neurites and provide only marginal neurotrophic support to dopaminergic neurons. Thus, dysfunctional astrocyte-to-neuron communication via altered EV biological properties may participate in the progression of PD. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.06.08.139675v1?rss=1 Authors: Kalogeropulou, A. F., Lis, P., Polinski, N. K., Alessi, D. R. Abstract: Mutations that enhance LRRK2 protein kinase activity cause inherited Parkinsons disease. LRRK2 phosphorylates a group of Rab GTPase proteins, including Rab10, within the effector-binding switch-II motif. Previous work has indicated that the PARK16 locus, which harbors the gene encoding for Rab29, is mutated in Parkinsons, and that Rab29 operates in a common pathway with LRRK2. Co-expression of Rab29 and LRRK2 stimulates LRRK2 activity by recruiting LRRK2 to the surface of the trans-Golgi network. Pathogenic mutations including LRRK2[R1441C] promote GTP-binding are more readily activated by Rab29. As previous work was based on overexpression approaches, we were curious to define the importance of endogenous Rab29 in regulating basal LRRK2 activity. We report that knock-out of Rab29 does not influence endogenous LRRK2 activity, based on assessment of Rab10 phosphorylation, in wildtype LRRK2, LRRK2[R1441C] as well as in VPS35[D620N] knock-in mouse tissues and embryonic fibroblasts. We also generated a transgenic mouse model that moderately overexpresses Rab29, and found that this was not sufficient to stimulate basal LRRK2 activity. Our data suggest that the bulk of the basal LRRK2 activity measured in whole cell and tissue extracts is not controlled by Rab29. LRRK2 is not associated with the Golgi unless Rab29 is highly overexpressed, which could account for the lack of effect that Rab29 knock-out or moderate overexpression has on basal LRRK2 activity. Further work is required to establish how basal LRRK2 activity is regulated, and whether other Rab proteins control basal LRRK2 by targeting it to diverse membranes. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.27.119388v1?rss=1 Authors: Liu, Q., Bautista-Gomez, J., Higgins, D. A., Yu, J., Xiong, Y. Abstract: Recent genetic evidence revealed that endocytic pathway plays a major role in Parkinsons disease (PD) risk. However, the molecular mechanism of how endocytic defects contribute to dopaminergic neurodegeneration in PD is poorly understood. Here we report that LRRK2, the mutations of which are the most genetic causes of PD, binds to and phosphorylates AP2M1, the core component of endocytosis that has been recently implicated in PD risk. Our study revealed that abnormal AP2M1 phosphorylation cycle, regulated either by knockout or overexpression of LRRK2, cause endocytic defects. Our study also uncovered a novel tissue-specific regulation of AP2M1 phosphorylation by LRRK2. Further, we found that LRRK2 phosphorylation on AP2M1 mediates LRRK2-induced neuronal toxicity both in vitro in neuronal cultures and in vivo in Drosophila dopamine neurons. Importantly, AP2M1 phosphorylation levels are elevated in patient fibroblasts of both LRRK2-associated PD and sporadic PD, suggesting the clinical relevance of our finding in PD. Together, our study provides a direct mechanistic link between LRRK2, AP2 and endocytosis in PD pathogenesis. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.04.077065v1?rss=1 Authors: Xu, E., Boddu, R., Abdelmotilib, H. A., Kelly, K., Sokratian, A., Harms, A. S., Schonhoff, A. M., Bryant, N., Harmsen, I. E., Schlossmacher, M., Chandra, S., Krendelshchikova, V., Liu, Z., West, A. B. Abstract: Missense mutations in the LRRK2 gene that lead to LRRK2 kinase hyperactivity can cause Parkinson's disease (PD). The link between LRRK2 and a-synuclein aggregation in PD remains enigmatic. Numerous reports suggest critical LRRK2 functions in microglial responses. Herein, we find that LRRK2-positive immune cells in the brain represent CD68-positive pro-inflammatory, monocyte-derived macrophages, distinct from microglia. Rod a-synuclein fibrils stimulate LRRK2 kinase activity in monocyte-derived macrophages, and LRRK2 mutations lead to enhanced recruitment of classical monocytes into the midbrain in response to a-synuclein. LRRK2 kinase inhibition blocks a-synuclein fibril induction of LRRK2 protein in both human and murine macrophages, with human cells demonstrating much higher LRRK2 levels and kinase activity than equivalent murine cells. Further, interferon-g strongly induces LRRK2 kinase activity in primary human macrophages in comparison to weak effects observed in murine cells. These results highlight peripheral immune responses in LRRK2-linked paradigms that further connect two central proteins in PD. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.05.02.073726v1?rss=1 Authors: Valderhaug, V. D., Ramstad, O. H., van de Wijdeven, R., Heiney, K., Nichele, S., Sandvig, A., Sandvig, I. Abstract: Mutations in the LRRK2 gene have been widely linked to Parkinson's disease. The G2019S variant has been shown to contribute uniquely to both familial and sporadic forms of the disease. LRRK2-related mutations have been extensively studied, yet the wide variety of cellular and network events directly or indirectly related to these mutations remain poorly understood. In this study, we structured multi-nodal human neural networks carrying the G2019S mutation using custom-designed microfluidic chips coupled to microelectrode-arrays. By applying live imaging approaches, immunocytochemistry and computational modelling, we have revealed alterations in both the structure and function of the resulting neural networks when compared to controls. We provide first evidence of increased neuritic density associated with the G2019S LRRK2 mutation, while previous studies have found either a strong decrease, or no change, compared to controls. Additionally, we corroborate previous findings regarding increased baseline network activity compared to control neural networks. Furthermore, we can reveal additional network alterations attributable to the specific mutation by selectively inducing transient overexcitation to confined parts of the structured multi-nodal networks. These alterations, which we were able to capture both at the micro- and mesoscale manifested as differences in relative network activity and correlation, as well as in mitochondria activation, neuritic remodelling, and synaptic alterations. Our study thus provides important new insights into early signs of neural network pathology significantly expanding upon the current knowledge relating to the G2019S Parkinson's disease mutation. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.27.053694v1?rss=1 Authors: Deshpande, P., Flinkman, D., Hong, Y., Goltseva, E., Siino, V., Sun, L., Peltonen, S., Elo, L., Kaasinen, V., James, P., Coffey, E. T. Abstract: Gain of function LRRK2-G2019S is the most common mutation associated with both familial and sporadic Parkinson's disease. It is expected therefore that understanding the cellular function of LRRK2 will provide much needed insight on the pathological mechanism of sporadic Parkinson's, which is the most common form. Here we show that constitutive LRRK2 activity represses nascent protein synthesis in rodent neurons. Specifically, enzymatic inhibition of LRRK2, gene silencing or gene knockout of Lrrk2 increase translation. In the rotenone model of Parkinson's, LRRK2 activity increases, leading to repression of translation and dopaminergic neuron atrophy both of which are prevented by LRRK2 inhibition. This is accompanied by altered phosphorylation of eIF2-S52({uparrow}), eIF2s2-S2({downarrow}) and eEF2-T57({uparrow}) in striatum/substantia nigra in a direction that signifies inhibition of protein synthesis. Significantly, LRRK2 is activated and translation is 40% reduced in Parkinson's patient fibroblasts (G2019S and sporadic) and LRRK2 inhibition restores normal translation. In contrast, translation is unchanged in cells from multiple system atrophy patients, implying disease specificity. These findings suggest that LRRK2-dependent repression of translation may be a proximal function of LRRK2 in Parkinson's pathology. Copy rights belong to original authors. Visit the link for more info

One of the exciting areas of research as it pertains to understanding Parkinson’s disease is in genetics. Dr. Matt Farrer is a Geneticist at the Djavad Mowafaghian Centre for Brain Health. In 2004, he found the first genetic connection to Parkinson’s, LRRK2, and his team has sincee identified about dozen others. Dr. Farrer is the first to admit Parkinson’s is not a genetic condition, but as with everything biological there is a genetic component, “The genetic component in Parkinson’s is 27%. That’s the variability in the condition that can be attributed to a genetic cause.” He explains that most people don’t have a clear cut passing of inheritance down the family line from their parents to them, for example. It does happen sometimes, but those families are pretty rare. Dr. Farrer is looking for unequivocal answers. He wants to know what the issue is from a molecular point of view down to a single protein. Once that is determined, Farrer and his team work backs to find out what that protein is doing in a cell, what that cell is doing in a brain and how the mutation discovered leads to disease. “The whole goal is to predict and prevent,” Dr. Farrer says when asked about the chances of a cure. “Cure is a difficult term. I would like to prevent symptoms from progressing. I would like to slow down or halt the disease in people who already have a diagnosis. I would like to prevent it in subjects who may be destined, for example, because of their genetics.” In Kyoto, Dr. Farrer will be discussing new insights into the function of LRRK2 from a genetic point of view. The information may be a bit heady for folks who aren’t researchers, but if you’re interested, Dr. Farrer encourages you not to be intimidated by esoteric terms he may use. Farrer concludes, “Everyone’s coming to Kyoto anyway, it is a strange place for many, but it’s a wonderful place. Get immersed in it.”  There are quite a few shout-outs to how beautiful Kyoto is. Here is a list of attractions that are listed by level of accessibility, which will help you plan which sites might be a best fit for your ability to get around the city. There is a magazine called Fokus. It’s like Sweden’s Time Magazine. Fokus’ 2018 Swede of the year in medicine was Sara Riggare. She was diagnosed with Parkinson’s in 2003. 18-years after her first symptoms first appeared. Riggare, co-chair of the Patients Advocate Committee for WPC2019, is self-described as a Parkinson’s “im”-patient. A chemical engineer by trade, she returned to school and is a PhD candidate researching digital self-care for Parkinson’s. Riggare is a proponent of making use of the possibilities of technology and the World Wide Web to benefit individuals with Parkinson’s and empower them with knowledge. “From doing that,” Riggare says, “I learned to observe my body more consciously and I think I’m more attuned to how my body works and the medication effects it.” Each episode of the WPC2019 Podcast, I’m going to check in with James Heron, the Executive Director of the Japanese-Canadian Cultural Centre to teach us a new word or phrase and help us better understand the culture so we can avoid embarrassing ourselves or offending our hosts.   When you are sitting down to eat or just before you eat, Heron explains that Japanese people will say, “itadakimasu” which is comparable to “Let’s eat” or “Bon appétit.” A pronunciation can be listened to if you google these phrases online.  When it comes to chop sticks, Heron suggests you practice before arriving, but if you are having troubles it is perfectly acceptable to ask for a spoon or a fork. “The important thing with chop sticks,” Heron cautions, “is not to stick them upright in your rice. That is something that is actually part of the funeral ritual.” Also, you should never pass food with your chop sticks and only use the ends of chop sticks that are not going in your mouth to take food off a shared plate. Heron also shared some notes regarding specific foods. When eating noodles, he says, it is okay to slurp. Sushi can be eaten with chopsticks, but is often a hand food. He says the Japanese do not pour soy sauce over anything and they only dip the fish side of the sushi into it, never the rice. Follow me, Larry Gifford  Twitter: @ParkinsonsPod Facebook: Facebook.com/ParkinsonsPod Instagram: @parkinsonspod For more info on the World Parkinson Congress head to www.WPC2019.org Facebook: Facebook.com/WorldPDCongress/ Twitter: @WorldPDCongress YouTube: WorldPDcongress Instagram: @worldpdcongress Thank you to: Dr. Matt Farrer, Geneticist at Djavad Mowafaghian Centre for Brain Health Sara Riggare, co-chair of the Patients Advocate Committee for WPC2019. She’s blogging here. James Heron, Executive Director of Japanese Canadian Cultural Centre  

Welcome to another episode of Biotechnology Focus radio! I am your host, Michelle Currie, here to give you the rundown on Canada’s biotech scene. This week we have stories about a possible Ebola treatment, how there may be a link between an increase in cholinergic system activity and parkinson’s disease, CRISPR makes its move on RNA, and according to a u of t study, rheumatoid arthritis patients have a higher risk of earlier mortality. So, keep listening to hear what’s going on from coast to coast! +++++ In the wake of the 2014 Ebola outbreak, with more than 11,000 known deaths, researchers are attempting to come up with innovative ways to prevent and cure the disease. Due to the dire nature of the virus, it sheds light on the limitations of the medication currently in circulation. Now, University of Guelph researchers have shown that an innovative antibody delivery method could offer an effective way to prevent and treat Ebola infection. Their goal is to make an antibody-based therapy that can protect against all strains of Ebola, and potentially the Marburg virus as well. It would be used to stop the spread of the virus in outbreak situations. The researchers say monoclonal antibody therapies (mAbs) hold promise for the treatment of the Ebola virus, but monoclonal antibody therapies are a costly operation and provide only short-term immunity. That could change though thanks to a recent discovery by lead researchers Sarah Wootton and Laura van Lieshout. Their findings were published in the Journal of Infectious Diseases. The approach technique that the researchers are using has been seen in studies with the human immunodeficiency virus (HIV). It delivers a monoclonal antibody gene through a viral vector to bypass the need to generate a natural immune response – something that can take the body weeks to occur and quite frankly, time is of the essence with this particular disease. Wootton found that using the adeno-associated virus (AAV) to deliver antibodies was remarkably effective at keeping the Ebola virus infection at bay in mice. Other researchers have used the adeno-associated virus extensively to treat a variety of genetic disorders. The goal is to use the adeno-associated virus gene therapy vector to deliver the DNA blueprint to a cell, and that cell will produce a protective antibody against the Ebola virus, which is then secreted into the bloodstream and protects mice from infection. The approach provided 100 per cent protection against an Ebola infection in mice using two separate types of monoclonal antibodies, and 83 per cent protection with a third. A “cocktail” of two antibodies provided sustained protection against Ebola for up to five months. Once the antibody gene is delivered, antibodies will be continually reproduced in the bloodstream. Mice in the laboratory expressed the antibody for more than 300 days. Researchers are hoping to utilize this technology in a post-exposure scenario. +++++ There is a particular gene mutation that happens in the brain that could be linked to an inherited form of Parkinson’s disease (PD) that might shed some light on a controversial theory about where PD begins in the brain. Idiopathic PD, a sporadic form of the disease, affects the dopamine system and is treated with replacement therapy to restore the brain’s natural chemical balance and alleviate physical symptoms. Frequently, other neurotransmitter systems are involved, but it is not yet clear whether this happens pre- or post the dopamine loss characteristic. By studying people with the inherited form of the disease, researchers hope that they will be able to determine brain involvement prior to the development of symptoms. The results of an international collaboration, led by Dr. Jon Stoessl, published in The Lancet Neurology shows that mutations in the LRRK2 – a gene associated with an inherited form of PD – can cause imbalances in the cholinergic system of the brain, but not in the way they thought. The cholinergic system is responsible for learning and memory. An imbalanced cholinergic system has been witnessed in other neurodegenerative disorders, including Alzheimer’s. While the investigators expected to find evidence of reduced cholinergic activity in the brain, positron emission tomography (PET) scans revealed widespread increases not only in people with the LRRK2 mutation-related form of PD, but also in unaffected individuals who carry the mutation but do not yet have manifestations of disease. Changes in the cholinergic system are thought to contribute to PD complications including cognitive difficulties, postural instability and sleep disturbances. It is possible that an increase in activity may reflect the brain’s attempt to compensate for dysfunction related to the mutated gene, and may also explain why patients with LRRK2 mutations have fewer problems with certain complications of disease, even though their PD is in most ways similar to the usual sporadic form of the disease. This provides a tremendous opportunity to study people with Parkinson-causing genetic mutations before they develop. The findings of this study have considerable implications for understanding how the disease begins to manifest in the years before diagnosis, and builds on research previously published last year that demonstrated that patients with the LRRK2 mutation show an increase in serotonin nerve terminals before a formal Parkinson’s Disease diagnosis, possibly reflecting the brain’s attempts to compensate for the decrease in dopamine associated with onset of physical symptoms. According to Statistics Canada, PD is the second most common neurodegenerative disease in Canada with an estimated 55,000 people suffering from it. It is a progressive disorder of the nervous system that affects movement. It develops gradually, sometimes starting with a barely noticeable tremor in just one hand. But while a tremor may be the most well-known sign of Parkinson’s disease, the disorder also commonly causes stiffness or slowing of movement that worsens as it progresses. The majority of new diagnoses are in adults over the age of 64. +++++ CRISPR/Cas9, the “scissors” of life sciences, is now not only targeting DNA, but RNA as well. Scientists from the Salk Institute in the U.S. have created this new tool, CasRx, to correct protein imbalances in cells. This provides researchers with a powerful way to develop new gene therapies, as well as investigate fundamental biological functions. Bioengineers are like nature’s detectives, searching for clues in patterns of DNA to help solve the mysteries of genetic diseases. CRISPR has revolutionized genome engineering, and the researchers wanted to expand the toolbox from DNA to RNA. CRISPR technology was adapted from the natural defense mechanisms of bacteria and archaea (the domain of single-celled microorganisms). These organisms use CRISPR-derived RNA and various Cas proteins, including Cas9, to foil attacks by viruses and other foreign bodies. They do so primarily by chopping up and destroying the DNA of a foreign invader. When these components are transferred into other, more complex, organisms, it allows for the manipulation of genes, or “editing.” The Salk team decided to search bacterial genomes for new CRISPR enzymes that could target RNA, which could then be engineered to address problems with RNA and resulting proteins. A given RNA message, for example, can be expressed at varying levels and its balance relative to other RNAs is critical for healthy function. Furthermore, RNA can be spliced in various ways to make different proteins, but problems with splicing can lead to diseases such as spinal muscular atrophy, atypical cystic fibrosis and frontotemporal dementia (FTD). So, a drug that targets toxic RNAs or RNAs resulting from improper splicing could have a life-changing impact for people with these types of devastating diseases. The researchers began the project with the hypothesis that different CRISPR systems may have been specialized throughout an evolutionary arms race between bacteria and their viruses, potentially giving them the ability to target viral RNA. They developed a computational program to search bacterial DNA databases for particular repeating DNA sequences. Whilst this was happening, they discovered a family of CRISPR enzymes that targets RNA. They called it Cas13. The name is derived from the gut bacterium Ruminococcus flaveflacians XPD3002 due to it being the best version for use in human cells, because just like Cas9, Cas13 enzymes originate from different bacterial species and vary in activity. The scientists tried out this new method in a dementia patient, attempting to replace the damaged cells with healthy ones. CasRx was 80 per cent effective. The team genetically engineered CasRx to target RNA sequences for the version of the tau protein that is overabundant. They did this by packaging CasRx into a virus and delivering it to neurons grown from a frontotemporal degeneration patient’s stem cells. Compared to other technologies that target RNA, CasRx is unique due to its small size – making it easier to package into therapeutically relevant viral vectors – its high degree of effectiveness, and that it creates no discernible off-target effects compared to RNA interference. The Salk team is excited about the possibilities their tool opens up for exploring new biological questions about RNA and protein function, as well as therapies to tackle RNA and protein-based diseases. To quote one of the authors of the study, “Nature is full of so many secrets. It’s really a rich, untapped resource for inventing new technologies.” +++++ According to a study done by the University of Toronto, sufferers of rheumatoid arthritis are more likely to have further complications and die at a younger age than the general population. The study was examining causes of death of Ontarians over a 14-year period. Everyone deserves to live the same length and quality of life. Mortality is also one of the strongest markers to evaluate inadequate care. The excess mortality related to rheumatoid arthritis that the researchers observed may suggest inadequate attention to control of the disease and its related morbidity. The study is one of the largest of its kind to comprehensively look at causes of death over an extended period. More than 87,000 patients with rheumatoid arthritis in Ontario were included in the study and compared with more than 340,000 members of the general population over a span of 14 years. Causes of death were found to be quite similar between the general population and those with rheumatoid arthritis, but the notable difference was that those with the disease were dying at a much younger age – which is something that concerns the researchers. Rheumatoid arthritis is a chronic condition that can affect two to three per cent of older adults. As an inflammatory disease, rheumatoid arthritis can affect more than just the joints in the body – ongoing inflammation often leads to further complications and multimorbidity in patients. This means that individuals will likely have multiple chronic conditions occurring simultaneously, such as diabetes and high blood pressure, or heart disease and a respiratory illness. The study also found that among arthritis sufferers, one in three were dying of complications attributed to heart disease. The head researcher wants to underscore the importance of improving preventative measures to slow down the progression of some of these co-morbid conditions in order to improve a patients’ overall life expectancy. The hope through this research is that it will shed light and awareness on the disease and inspire patients to play a more active and vigilant role when it comes to their health. The study was published in Arthritis Care & Research and was supported by the Catherine and Fredrik Eaton Charitable Foundation, the Canadian Institutes of Health Research, and the Arthritis Society Post Doctoral Fellowship. +++++ Well, that wraps up another episode of Biotechnology Focus radio! I hope you enjoyed it! Next week I’ll have Vatche Bartekian on the show to tell me about his event coming up in May! Stay tuned and have a great week! From my desk to yours – this is Michelle Currie.

In this podcast, MJFF staff scientist Marco Baptista, PhD, discusses the genetics and biology of LRRK2 and the role of the Foundation in advancing development of LRRK2 therapeutics.

MDS presents the latest research and findings from the field of Movement Disorders. Abstracts of articles from the Society Journal, Movement Disorders, are taken from the June 2015 Issue.

It’s all about innovation at OYM this week, from the interactive mouse connectome to patient-derived organ transplants.  Plus, we’re talking about the importance of critical journalism in science communication and the interactions between LRRK2 and ribosomal proteins in Parkinson’s disease. 

MDS presents the latest research and findings from the field of Movement Disorders. Abstracts of articles from the Society Journal, Movement Disorders, are taken from the October 2013 (Vol. 28, Issue 12) issue.

MDS presents the latest research and findings from the field of Movement Disorders. Abstracts of articles from the Society Journal, Movement Disorders, are taken from the October 2013 (Vol. 28, Issue 12) issue.

March 3, 2013 - Dr. Ana Maria Cuervo has discovered why toxic clumps of proteins accumulate in brain cells of those with a familial form of Parkinson's disease. The paper was published online March 3 in Nature Neuroscience. Dr. Cuervo is professor of developmental & molecular biology and the Robert and Renee Belfer Chair for the Study of Neurodegenerative Diseases at Albert Einstein College of Medicine. See accompanying release:http://www.einstein.yu.edu/news/releases/875/scientists-identify-clean-up-snafu-that-kills-brain-cells-in-parkinsons-disease/

MDS presents the latest research and findings from the field of Movement Disorders. Abstracts of articles from the Society Journal, Movement Disorders, are taken from the December 2012 (Vol. 27, Issue 14) issue.

Understanding the genetics of Parkinson's disease could be a game changer in developing new treatments for the disease. Especially when it comes to two genetic targets: LRRK2 and alpha-synuclein.

The International LRRK2 Consortium, which includes investigators in 21 centres, has collected data from almost 20000 patients with Parkinson's disease carrying mutations in the LRRK2 gene. The Lancet Neurology editor Elena Becker-Barroso and Daniel Healy, the corresponding author on their first report, summarises the findings and their implications in clinical practice in a podcast.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.04.10.035758v1?rss=1 Authors: Petridi, S., Middleton, C. A., Covill, L., Elliott, C., Fellgett, A., Ugbode, C. Abstract: LRRK2 mutations cause Parkinson's, but the molecular link from increased kinase activity to pathological neurodegeneration remains undetermined. Previous in vitro assays indicate that LRRK2 substrates include at least 8 Rab GTPases. We have now examined this hypothesis in vivo in a functional, electroretinogram screen, expressing each Rab with/without LRRK2-G2019S in selected Drosophila dopaminergic neurons. Our screen discriminated Rab10 from Rab3. The strongest Rab/LRRK2-G2019S interaction is with Rab10; the weakest with Rab3. Rab10is expressed in dopaminergic neurons controlling vision where Rab3 is undetectable. Thus, anatomical and physiological patterns of Rab10 are related. We conclude that Rab10 is a valid substrate of LRRK2 in dopaminergic neurons in vivo. We propose that variations in Rab expression contribute to differences in the rate of neurodegeneration recorded in different dopaminergic nuclei in Parkinson's. Copy rights belong to original authors. Visit the link for more info