Podcasts about STAT1

BUFFALO, NY- August 21, 2024 – A new #editorial was #published in Oncotarget's Volume 15 on July 17, 2024, entitled, “Strategies to disrupt NKG2A:HLA-E interactions for improved anti-cancer immunity.” Two studies using CRISPR screens in cancer cells identified HLA-E as a critical negative regulator of NK cell interactions with cancer cells. Consistent with this, IFNγ signaling was associated with NK cell resistance due to increased STAT1 activation and enhanced HLA-E expression. This effect is also evident in the murine homolog of HLA-E, Qa-1b, which was upregulated by inflammatory signals across all cell types tested. In addition to inflammatory signals, researchers Jack G. Fisher, Lara V. Graham, and Matthew D. Blunt from Clinical and Experimental Sciences, Faculty of Medicine at the University of Southampton, UK, recently demonstrated that surface expression of HLA-E is increased by lymph node-associated signals IL-4 and CD40L on primary chronic lymphocytic leukaemia (CLL) cells. Additionally, two recent studies have shown that HLA-E can protect circulating tumor cells from NK cell lysis via NKG2A, suggesting that targeting the NKG2A axis could be a promising strategy for preventing metastasis in solid tumors. “In conclusion, there is strong preclinical evidence that disruption of NKG2A interactions with HLA-E can stimulate both NK cell and cytotoxic T cell effector functions against cancer.” DOI - https://doi.org/10.18632/oncotarget.28610 Correspondence to - Matthew D. Blunt - m.d.blunt@soton.ac.uk Video short - https://www.youtube.com/watch?v=iQREIa-RToU Sign up for free Altmetric alerts about this article - https://oncotarget.altmetric.com/details/email_updates?id=10.18632%2Foncotarget.28610 Subscribe for free publication alerts from Oncotarget - https://www.oncotarget.com/subscribe/ Keywords - cancer, Natural killer (NK) cells, immunotherapy, NKG2A, immune checkpoint blockade, HLA-E About Oncotarget Oncotarget (a primarily oncology-focused, peer-reviewed, open access journal) aims to maximize research impact through insightful peer-review; eliminate borders between specialties by linking different fields of oncology, cancer research and biomedical sciences; and foster application of basic and clinical science. Oncotarget is indexed and archived by PubMed/Medline, PubMed Central, Scopus, EMBASE, META (Chan Zuckerberg Initiative) (2018-2022), and Dimensions (Digital Science). To learn more about Oncotarget, please visit https://www.oncotarget.com and connect with us: Facebook - https://www.facebook.com/Oncotarget/ X - https://twitter.com/oncotarget Instagram - https://www.instagram.com/oncotargetjrnl/ YouTube - https://www.youtube.com/@OncotargetJournal LinkedIn - https://www.linkedin.com/company/oncotarget Pinterest - https://www.pinterest.com/oncotarget/ Reddit - https://www.reddit.com/user/Oncotarget/ Spotify - https://open.spotify.com/show/0gRwT6BqYWJzxzmjPJwtVh MEDIA@IMPACTJOURNALS.COM

In this study, researchers found that the genetic material from the virus and possibly other parts activate TLR3 receptors. These in turn cause the cells to release IFN1. IFN1 works on the intestinal cells via STAT1 pathway to down-regulate ACE2 receptors and B0AT1 channels. The result is reduced absorption of tryptophan leading to reduced serotonin production in the body. They also found that IFN1 activates platelets leading to micro thrombi and further reduction of serotonin as platelets are a huge reservoir of serotonin. Researchers also found that MAO activity was increased. Vagal activity was reduced leading to the hippocampal reduction in function as well. The researchers suggest using tryptophan precursor supplement (5HTP - 5 hydroxytryptophan) and SSRI medications to rescue serotonin levels in long COVID patients. DrBeen: Medical Education Onlinehttps://www.drbeen.com/ FLCCC | Front Line COVID-19 Critical Care Alliancehttps://covid19criticalcare.com/ URL List (Nov. 24 2023) Serotonin reduction in post-acute sequelae of viral infection: Cellhttps://www.cell.com/cell/fulltext/S0092-8674(23)01034-6#gr2 Serotonin in Platelets - ScienceDirecthttps://www.sciencedirect.com/science/article/abs/pii/B978012800050200005X IJMS | Free Full-Text | The Mechanism of Secretion and Metabolism of Gut-Derived 5-Hydroxytryptaminehttps://www.mdpi.com/1422-0067/22/15/7931 ijms-22-07931-g001.png (3550×2309)https://www.mdpi.com/ijms/ijms-22-07931/article_deploy/html/images/ijms-22-07931-g001.png Uptake and release of serotonin by blood platelets. Serotonin is taken... | Download Scientific Diagramhttps://www.researchgate.net/figure/Uptake-and-release-of-serotonin-by-blood-platelets-Serotonin-is-taken-up-from-the_fig2_367097021 Indoleamine 2,3-dioxygenase - Wikipediahttps://en.wikipedia.org/wiki/Indoleamine_2,3-dioxygenase#:~:text=Indoleamine%2Dpyrrole%202%2C3%2D,female%20genital%20tract%20or%20placenta. Frontiers | Kynurenine Pathway Metabolites as Biomarkers for Amyotrophic Lateral Sclerosishttps://www.frontiersin.org/articles/10.3389/fnins.2019.01013/full Toll-like receptor 3 (TLR3) regulation mechanisms and roles in antiviral innate immune responses - PMChttps://www.ncbi.nlm.nih.gov/pmc/articles/PMC8377577/#:~:text=Toll%2Dlike%20receptor%203%20(TLR3)%20is%20a%20member%20of,establishing%20an%20antiviral%20host%20response. Mechanisms of type-I- and type-II-interferon-mediated signalling | Nature Reviews Immunologyhttps://www.nature.com/articles/nri1604 Disclaimer:This video is not intended to provide assessment, diagnosis, treatment, or medical advice; it also does not constitute provision of healthcare services. The content provided in this video is for informational and educational purposes only. Please consult with a physician or healthcare professional regarding any medical or mental health related diagnosis or treatment. No information in this video should ever be considered as a substitute for advice from a healthcare professional.

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.04.19.537577v1?rss=1 Authors: Laban, H., Froemel, T., Fleming, I., Benz, P. M. Abstract: Macrophage polarization plays an important role in tissue regeneration. Numerous factors and signaling molecules affect polarization processes. Here we investigated the consequences of the genetic deletion of vasodilator-stimulated phosphoprotein (VASP), which increases macrophage M1 polarization through augmented signal transducer and activator of transcription 1 (STAT1) signaling, and AMP-activated protein kinase (AMPK), which attenuates inflammation by inhibiting STAT1 expression and signaling. While a basal activity of AMPK (phosphorylation on Thr172) was detected in macrophages from wild-type mice, AMPK phosphorylation was significantly reduced in VASP-deficient M1 macrophages in vitro and the expression of the pro-inflammatory cytokines TNF and IL-1{beta} was increased in these cells. Consistent with the role of AMPK in macrophage phagocytosis, VASP-/- macrophage phagocytosis was also significantly impaired. Interestingly, impaired phagocytosis could be rescued by exogenous activation of AMPK. Mechanistically, we found that VASP binds directly to protein phosphatase 1 regulatory subunit 6 (PP1-R6) and we hypothesize that VASP-binding to PP1-R6/PP1 limits the PP1-dependent de-phosphorylation of AMPK in wild-type cells. Conversely, AMPK dephosphorylation by the PP1-R6/PP1 complex is enhanced in the absence of VASP. In summary, we have identified a link between VASP and AMP-activated protein kinase (AMPK) activity, which may contribute to the pro-inflammatory phenotype of VASP-deficient macrophages. 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/2023.04.13.536755v1?rss=1 Authors: Helbing, D. L., Haas, F., Cirri, E., Rahnis, N., Dau, T. T. D., Sacramento, E. K., Oraha, N., Boehm, L., Morrison, H., Bauer, R. Abstract: Preconditioning with LPS induces neuroprotection against subsequent cerebral ischemic injury, mainly involving innate immune pathways. Microglia are CNS-resident immune cells that respond early to danger signals through memory-like differential reprogramming. However, the cell-specific molecular mechanisms underlying preconditioning are not fully understood. To elucidate the distinct molecular mechanisms of preconditioning on microglia, we compared these cell-specific proteomic profiles in response to LPS preconditioning and without preconditioning and subsequent transient focal brain ischemia and reperfusion, using an established mouse model of transient focal brain ischemia and reperfusion. A proteomic workflow, based on isolated microglia obtained from mouse brains by cell sorting and coupled to mass spectrometry for identification and quantification, was applied. Our data confirm that LPS preconditioning induces marked neuroprotection, as indicated by a significant reduction in brain infarct volume. The established brain cell separation method was suitable for obtaining an enriched microglial cell fraction for valid proteomic analysis. The results show a significant impact of LPS preconditioning on microglial proteome patterns by type I interferons, presumably driven by the interferon cluster regulator proteins Stat1/2. 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/2023.01.06.523065v1?rss=1 Authors: Feng, J., Tang, Y., Fu, W., Xu, H. Abstract: The highly prevalent herpes simplex virus type 1 (HSV-1) causes keratoconjunctivitis and encephalitis. Viral DNA polymerase-inhibiting nucleoside analogs (such as acyclovir) are standard treatment agents against HSV infections but are limited by severe drug resistance issues. Thus, new antiviral agents with novel targets are urgently needed. Earlier, we investigated the anti-cancer, anti-inflammatory, and antibacterial bioactivities of Garcinia sp. Here, we report that non-cytotoxic concentrations ( less than 500 nM) of Gaudichaudione H (GH, isolated from Garcinia oligantha Merr.) potently inhibits HSV-1 replication in vitro without affecting viral entry or attachment. GH inhibits the expression of the viral proteins ICP0, ICP4, and ICP27 without affecting their mRNA levels. In Vero cells, GH enhanced STAT1 and 3 phosphorylation, which occurs downstream to interferon (IFN)-{gamma} activation during viral infections. However, pharmacological/genetic inhibition of IFN-{gamma} failed to suppress the GH-mediated inhibition of HSV-1 replication, indicating that GH exerts antiviral effects independent of IFN. Further mechanistic studies suggest that GH inhibits HSV-1 replication, at least partially by inhibiting cellular NF-{kappa}B activation. Moreover, GH prolonged the survival rate of KOS-infected mice by 25% (n = 5). In conclusion, GH treatment inhibits HSV-1 replication both in vitro and in vivo; therefore, it can be developed as an antiviral. 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/2022.12.27.522037v1?rss=1 Authors: Dos Santos, R. S., Guzman-Llorens, D., Perez-Serna, A. A., Nadal, A., Marroqui, L. Abstract: Aims/hypothesis: Type 1 diabetes is characterised by pancreatic islet inflammation and autoimmune-driven pancreatic beta cell destruction. Type I interferons, such as IFNalpha, are key players in early human type 1 diabetes pathogenesis, as the activation of the tyrosine kinase 2 (TYK2)-signal transducer and activator of transcription (STAT) pathway induces inflammation, a long-lasting MHC class I overexpression, endoplasmic reticulum (ER) stress, and beta cell apoptosis (in synergy with IL-beta). As TYK2 inhibition has been suggested as a potential therapeutic target for the prevention or treatment of type 1 diabetes, we investigated whether the selective TYK2 inhibitor deucravacitinib could protect beta cells against the damaging effects of IFNalpha and other proinflammatory cytokines (i.e. IFNgamma and IL-1beta). Methods: Inflammation, ER stress, and apoptosis were evaluated by real-time PCR, immunoblot, immunofluorescence, and nuclear dyes. The promoter activity was assessed by luciferase assay and insulin secretion and content by ELISA. All experiments were performed in the human EndoC-betaH1 cell line. Results: Pre-treatment with deucravacitinib prevented IFNalpha effects, such as STAT1 and STAT2 phosphorylation and protein expression as well as MHC class I hyperexpression, in a dose-dependent manner without affecting beta cell survival and function. Comparison between deucravacitinib and two Janus kinase inhibitors, ruxolitinib and baricitinib, showed that deucravacitinib blocked IFNalpha- but not IFNgamma-induced signalling pathway. Pre-treatment with deucravacitinib protected beta cells from the pro-apoptotic and proinflammatory effects of two different combinations of cytokines: IFNalpha + IL-beta and IFNgamma + IL-1beta. Moreover, this TYK2 inhibitor could partially revert apoptosis and inflammation in cells previously treated with IFNalpha + IL-1beta or IFNgamma + IL-beta. Conclusions/interpretation: Our findings suggest that, by protecting beta cells against the deleterious effects of proinflammatory cytokines without affecting beta cell function and survival, deucravacitinib could be repurposed for the prevention or treatment of early type 1 diabetes. 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/2022.11.29.518315v1?rss=1 Authors: Frorup, C., Gerwig, R., Sondergaard Svane, C. A., Mendes Lopes de Melo, J., Floyel, T., Pociot, F., Kaur, S., Storling, J. Abstract: ObjectiveEndoC-{beta}H5 is a newly established human beta-cell model which may be superior to previous models of native human beta cells. Exposure of beta cells to proinflammatory cytokines is a widely used in vitro model of immune-mediated beta-cell failure in type 1 diabetes and we therefore performed an in-depth characterisation of the effects of cytokines on EndoC-{beta}H5 cells. MethodsThe sensitivity profile of EndoC-{beta}H5 cells to the toxic effects of the pro-inflammatory cytokines interleukin-1{beta} (IL-1{beta}), interferon {gamma} (IFN{gamma}) and tumour necrosis factor- (TNF) was examined in titration and time-course experiments. Cell death was evaluated by caspase 3/7 activity, cytotoxicity, viability, TUNEL assay and immunoblotting. Mitochondrial function was evaluated by extracellular flux technology. Activation of signalling pathways and major histocompatibility complex (MHC) class I expression were examined by immunoblotting, immunofluorescence, and real-time quantitative PCR (qPCR). Glucose-stimulated insulin secretion (GSIS) and cytokine-induced chemokine secretion were measured by ELISA and Meso Scale Discovery multiplexing electrochemiluminescence, respectively. Global gene expression was characterised by stranded RNA sequencing. ResultsCytokines increased caspase activity and cytotoxicity in EndoC-{beta}H5 cells in a time- and dose-dependent manner. The proapoptotic effect of cytokines was primarily driven by IFN{gamma}. Cytokine exposure caused impaired mitochondrial function, diminished GSIS, and induced secretion of chemokines. At the signalling level, cytokines increased the phosphorylation of signal transducer and activator of transcription 1 (STAT1) but not c-jun N-terminal kinase (JNK) and did not cause degradation of nuclear factor of kappa light polypeptide gene enhancer in B-cells inhibitor (I{kappa}B). MHC class I was induced by cytokines. Cytokine exposure caused significant changes to the EndoC-{beta}H5 transcriptome including upregulation of HLA genes, endoplasmic reticulum stress markers, and non-coding RNAs. Among the differentially expressed genes were several type 1 diabetes risk genes. ConclusionsOur study provides detailed insight into the functional and transcriptomic effects of cytokines on EndoC-{beta}H5 cells. This knowledge will be helpful for future investigations studying cytokine effects in this cell model. 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/2020.05.19.105171v1?rss=1 Authors: Cirnaru, M.-D., Song, S., Tshilenge, K.-T., Corwin, C., Mleczko, J., Galicia Aguirre, C., Benlhabib, H., Bendl, J., Fullard, J., Apontes, P., Creus Muncunill, J., Carlsson, P., Mooney, S. D., Roussos, P., Ellerby, L., Ehrlich, M. E. Abstract: The basal ganglia, best known for processing information required for multiple aspects of movement, is also part of a network which regulates reward and cognition. The major output nucleus of the basal ganglia is the striatum, and its functions are dependent on neuronal compartmentation, including striosomes and matrix, which are selectively affected in disease. Striatal projection neurons are GABAergic medium spiny neurons (MSNs), all of which share basic molecular signatures but are subtyped by selective expression of receptors, neuropeptides, and other gene families. Neurogenesis of the striosome and matrix occurs in separate waves, but the factors regulating terminal neuronal differentiation following migration are largely unidentified. We performed RNA- and ATAC-seq on sorted murine striosome and matrix cells at postnatal day 3. Focusing on the striosomal compartment, we validated the localization and role of transcription factors and their regulator(s), previously not known to be associated with striatal development, including Irx1, Foxf2, Olig2 and Stat1/2. In addition, we validated the enhancer function of a striosome-specific open chromatin region located 15Kb downstream of the Olig2 gene. These data and data bases provide novel tools to dissect and manipulate the networks regulating MSN compartmentation and differentiation and thus provide new approaches to establishing MSN subtypes from human iPSCs for disease modeling and drug discovery. Copy rights belong to original authors. Visit the link for more info

This JCO Podcast provides observations and commentary on the JCO article “PET Score Has Greater Prognostic Significance Than Pre-Treatment Risk Stratification in Early-Stage Hodgkin Lymphoma in the UK NCRI RAPID Study” by Barrington et al. My name is Brue Cheson, and I am at Georgetown University Hospital, Lombardi Comprehensive Cancer Center. My Hematologic-oncologic specialty is Lymphoma.   Hodgkin lymphoma is clearly one of the most dramatic success stories in modern oncology. More than 90% of patients with limited disease and about 85% with advanced disease are cured using conventional chemotherapy regimens.  As a consequence, current clinical trials are focusing on augmenting or modifying treatment for those at higher risk and decreasing the intensity or duration of therapy for those at a lower risk of treatment failure.   One important question has been: how best to distinguish those disparate groups?  Over the years, various prognostic scoring systems have been devised.  The International Prognostic Scoring System (IPSS) differentiated patients into 6 groups using 7 clinical and laboratory factors.  However, only 7% of patients are in both the most and least favorable groups.  The German Hodgkin study Group (GHSG) and the EORTC each published criteria slightly different from each other for treatment selection.  Nevertheless, it is not clear that any of these schemas remains relevant in the context of current Hodgkin regimens.  More importantly, they do not reliably dictate how to treat patients, nor do they offer therapeutic targets.   FDG-PET scanning has revolutionized our management of patients with lymphoma.  In 2005 we first demonstrated that integration of PET into standard response assessment improved the ability to distinguish between residual tumor and fibrosis in patients with diffuse large B-cell lymphoma, leading to a revision of standardized response criteria. More recent studies have confirmed this observation in Hodgkin lymphoma and other histologies. Patients with advanced Hodgkin lymphoma can be distinguished into high and low risk groups based on PET scan results after 2 cycles of standard ABVD chemotherapy, regardless of their pretreatment IPSS score.  In a number of studies, reacting to the positive interim scan by intensifying therapy achieved outcomes markedly improved over expected.   In the paper that accompanies this podcast, Sally Barrington and her colleagues performed a secondary analysis of the RAPID trial to evaluate the role of pre-treatment risk factors and PET results in predicting outcome of patients with early stage Hodgkin lymphoma.  This study accrued 602 patients who were treated with standard ABVD and underwent PET scanning after the third cycle.  Those with a negative scan (a Deauville score of 1-2) were randomized to no further treatment vs involved field radiotherapy.  Despite a failure to demonstrate non-inferiority of progression-free survival in this cohort, the overall survival was the same, thus sparing 90% of patients unnecessary radiotherapy.  Those with a positive scan (defined as a Deauville score of 3-5), the primary focus of the current manuscript, received an additional cycle of ABVD plus radiotherapy.  Only the 21 patients with a Deauville score of 5, defined as an SUV at least 3 times greater than that of the liver, had an inferior time to progression or greater risk of Hodgkin-related death.  Importantly, this finding was independent of pretreatment prognostic factors using either the GHSG or EORTC scores.  Whether this observation can be extrapolated to patients with features not eligible for the RAPID study, such as those with bulky mediastinal disease or B-symptoms, is presently unknown.  Nonetheless, these data support the role of metabolic imaging over standard clinical and laboratory risk factors.   But we are clearly doing this all wrong.  Why do we treat all patients the same and then wait until the disease has demonstrated resistance before we alter therapy?  Several recent papers support the notion that anticipatory, biologically-based, risk-adapted approaches may be feasible. Pre-treatment total metabolic tumor volume (defined as the sum total of all metabolically active lesions) can predict outcome in Hodgkin lymphoma as well as follicular, diffuse large B-cell and primary mediastinal large B-cell lymphoma.  High heterogeneity of intratumoral FDG uptake distribution on PET-CT may be a marker of chemoresistance in solid tumors as well as various lymphoma histologies.  Unfortunately, those tests do not provide a target against which to direct a specific agent.  In contrast, a number of investigators have demonstrated a correlation between bcl-2, p53, FOXP3, CD68, STAT1, pattern of PD-1 expression, mutational patterns derived from next generation sequencing, and other factors in pre-treatment Hodgkin node biopsies and outcome.  Thus, if we are able to predict outcome prior to treatment, why do we expose patients to drugs to which we know they will not benefit? The goal of treatment should be anticipatory, risk-adapted strategies whereby patients with a high likelihood of benefit may receive standard of care, unless there is another clinical question being addressed.  On the other hand, those unlikely to benefit as determined prior to therapy should be spared the waste of time and toxicity and treated with novel regimens directed at specific targets.  Both groups should be monitored during treatment for the emergence of mutations, with treatment altered accordingly.  Yes, we may be a long way from having the appropriate tools for such an approach.  But, to quote the geneticist, molecular engineer and chemist George M. Church, “The best way to predict the future is to change it”.  Anticipatory, risk-adapted strategies could do just that.   This concludes this JCO Podcast. Thank you for listening.

Hosts: Vincent Racaniello, Dickson Despommier, Alan Dove and Kathy Spindler Guests: Nels Elde and Edward Chuong Nels and Ed join the TWiV team to talk about their observation that regulation of the human interferon response depends on regulatory sequences that were co-opted millions of years ago from endogenous retroviruses.   Links for this episode Endogenous retroviruses and regulation of innate immunity (Science) Placenta is viral (Nature) An ERV that maintains pluripotency of human embryonic stem cells (TWiV 279) Letters read on TWiV 382 This episode is sponsored by ASM Agar Art Contest and ASV 2016 Weekly Science Picks Nels - Don't Get Me Started - Matt GiorgianniAlan - Sun's magnetic field (paper)Dickson - Most realistic dinosaur terrifiesVincent - Top secret!Kathy - Zika virus risk for US 50 cities (paper)Ed - Watching comb jellies poop Listener Picks Asal - Lost paper of Gregor MendelDennis - PhysicsGirlJacob - Second (XKCD) and ACI blogger interview Send your virology questions and comments to twiv@microbe.tv

Specific differences in signaling and antiviral properties between the different Lambda-interferons, a novel group of interferons composed of IL-28A, IL-28B and IL-29, are currently unknown. This is the first study comparatively investigating the transcriptome and the antiviral properties of the Lambda-interferons IL-28A and IL-29. Expression studies were performed by microarray analysis, quantitative PCR (qPCR), reporter gene assays and immunoluminometric assays. Signaling was analyzed by Western blot. HCV replication was measured in Huh-7 cells expressing subgenomic HCV replicon. All hepatic cell lines investigated as well as primary hepatocytes expressed both IFN-λ receptor subunits IL-10R2 and IFN-λR1. Both, IL-28A and IL-29 activated STAT1 signaling. As revealed by microarray analysis, similar genes were induced by both cytokines in Huh-7 cells (IL-28A: 117 genes; IL-29: 111 genes), many of them playing a role in antiviral immunity. However, only IL-28A was able to significantly down-regulate gene expression (n = 272 down-regulated genes). Both cytokines significantly decreased HCV replication in Huh-7 cells. In comparison to liver biopsies of patients with non-viral liver disease, liver biopsies of patients with HCV showed significantly increased mRNA expression of IL-28A and IL-29. Moreover, IL-28A serum protein levels were elevated in HCV patients. In a murine model of viral hepatitis, IL-28 expression was significantly increased. IL-28A and IL-29 are up-regulated in HCV patients and are similarly effective in inducing antiviral genes and inhibiting HCV replication. In contrast to IL-29, IL-28A is a potent gene repressor. Both IFN-λs may have therapeutic potential in the treatment of chronic HCV.

In den vergangenen Jahren ist es gelungen mittels verbesserter Fahrzeugtechniken, verkürzten Rettungszeiten und verbesserten Primärversorgungskonzepten, sowie standardisiertem Schockraum-Management und kontinuierlich optimierter intensivmedizinischer Behandlung, etc. die frühe Mortalität nach schwerem Polytrauma zu senken. Immer weniger Patienten versterben somit an den direkten Traumafolgen. Im weiteren Verlauf jedoch versterben noch immer bis zu 30 % an den Folgen eines posttraumatischen MOF. Somit stellt dieses immunologische Phänomen die schwerwiegendste Komplikation nach Polytrauma dar. In diesem Zusammenhang haben verschiedene Autoren versucht, jene Faktoren und Mechanismen zu identifizieren, die den Organismus dazu bewegen, seine eigenen, von dem initialen Trauma nicht betroffenen Organe zu zerstören. Jüngste Veröffentlichungen geben starke Hinweise darauf, dass der gefürchteten Ausbildung einer posttraumatischen Immunsystemdysfunktion mit konsekutivem Organversagen die Fehlfunktion immunkompetenter Zellen (Monozyten, Granulozyten) vorausgeht. Ferner sind intrazelluläre Netzwerke zahlreicher pro- und antiinflammatorischer Mediatoren, die in komplexen Verkettungen miteinander interagieren, daran beteiligt. Die intrazellulären Steuerungsmechanismen, die diese Fehlfunktion induzieren und regulieren, sind bislang jedoch weitgehend unerforscht. Zahlreiche Studien belegen, dass insbesondere Zytokine und ihre Signaltransduktionskaskaden an der Immunantwort beteiligt sind. Deren initiierende Steuerung ist jedoch weitgehend unbekannt. Von besonderer Bedeutung sind in diesem Zusammenhang die Transkriptionsfaktoren, da diese über die Expression von Reporter- und Effektorgenen entscheiden und sowohl hemmende als auch aktivierende Effekte ausüben können. Zahlreiche Untersuchungen weisen auf die Bedeutung der Signal Transducer and Activator of Transcription (STAT) Proteine in Inflammationsreaktionen hin. Bislang liegen jedoch noch keine Daten über die Aktivierung von STAT1 und STAT3 in immunkompetenten Zellen polytraumatisierter Patienten vor. Kenntnisse dieser Aktivität wären jedoch klinisch von essentieller Bedeutung für das Verständnis der posttraumatischen Immunreaktion und für die Entwicklung potentieller innovativer Therapiestrategien. Ziel der vorliegenden Arbeit war es daher, die DNA-Bindungsaktivität dieser Transkriptionsfaktoren in Monozyten und Granulozyten von Normalprobanden und schwerst verletzten Patienten in der initialen Phase nach Polytrauma zu analysieren und die Ergebnisse mit den klinischen Parametern wie Überleben, Verletzungsschwere und erhaltener Massentransfusion zu vergleichen. Zu diesem Zweck wurden polytraumatisierte Patienten mit einem Injury Severity Score größer 16 Punkten eingeschlossen. Die Blutabnahmen erfolgten zu festgelegten Abnahmezeitpunkten, nämlich initial nach Trauma und nach 6, 12, 24, 48 und 72h. Wobei die Initialabnahme innerhalb der ersten 90min nach Trauma erfolgte. Zur Zellisolation wurden aus dem entnommenen EDTA-Vollblut mittels positiven cell-sortings durch magnetische AK-Markierung CD-14 positive Monozyten und CD 15 positive Granulozyten isoliert. Das nukleäre Protein aus diesen wurde radioaktiv markiert und mittels EMSA elektrophoretisch aufgetrennt um so die DNA-Bindungsaktivität von STAT3 und STAT1 quantitativ nachzuweisen. Zusätzlich wurden Monozyten und Granulozyten gesunder Normalprobanden als Negativkontrolle bzw. mit LPS stimuliert als Positivkontrolle untersucht. Die Ergebnisse zeigen die DNA Bindungsaktivität von STAT1 und STAT3 in den Normalprobanden signifikant erhöht nach LPS Stimulation. Bei den Patienten konnte in beiden Zellpopulationen eine erhöhte Aktivität von STAT1 und STAT3 im Vergleich zur Nativkontrolle detektierte werden. Die Aufteilung des Kollektivs hinsichtlich klinischer Parameter wie outcome, Verletzungsschwere und erhaltener Massentransfusion zeigt, dass Patienten mit einem schlechteren klinischen Verlauf eine Reduktion der Aktivität von STAT1 und STAT3 in beiden Zellpopulationen aufweisen. Die vorgelegten Ergebnisse sind eine erstmalige Analyse der intranukleären DNA-Bindungsaktivität von STAT1 und STAT3 in polytraumatisierten Patienten in der direkt posttraumatischen Phase. Die frühe Induktion der Bindungsaktivität in Monozyten und Granulozyten im gesamten Kollektiv weist auf die beginnende systemische Entzündungsreaktion hin, und die Reduktion in massentransfundierten bzw. verstorbenen Patienten auf die bereits postulierte Unfähigkeit des Immunsystems, nach schwererer Verletzung adäquat zu reagieren. Die Daten sind Grundlage weiterer Folgeuntersuchungen wobei insbesondere die Frage nach der biologischen Relevanz mittels Reportergenexpression untersucht werden sollte.

The incidence of high grade B cell lymphoma in western countries has increased over the last decades. Improvement of conventional chemotherapy regimens has significantly contributed to prolonged 5-year survival rates which currently reach around 60%. However, relapse after conventional chemotherapy is an important challenge, especially in high grade B cell lymphomas. The potential benefit of immunological approaches for the elimination of such lymphomas still remains unclear. In this study, we attempted to address whether the forced expression of foreign antigens in a tumor of B cell origin leads to immune recognition and elimination of the tumor and to assess the potential role of IFN-gamma (IFN-g) in tumor rejection. To this end, we used a transgenic mouse lymphoma model, where the human proto-oncogene c-myc (a foreign antigen for the mouse host) is under the control of regulatory elements of the immunoglobulin lambda locus, thereby recapitulating the important features of a t(8;22) translocation as found in human Burkitt’s lymphoma. From these spontaneously developing tumors, lymphoma cell lines were established that either express (line 291) or are deficient (line 9) in Stat1- a key signaling molecule in the response to interferons. We found that the expression of foreign antigens such as chicken ovalbumin (OVA) and green fluorescent protein (GFP) in Stat1-competent 291 cells led to immune responses that delayed tumor progression and improved survival of wild-type animals. Consistent with this, loss of foreign antigen inevitably led to accelerated tumor progression upon transfer into immunocompetent wild-type mice. Transfer of immunogenic 291-OVA-GFP lymphoma cells led to increased tumor progression without loss of foreign antigen upon transfer into IFN-γ-/- and Stat1-/- mice indicating that no selection of antigen loss-variants occurred in these mice. The rejection of 291-OVA-GFP cells in wild-type mice was at least in part mediated by CD8+ T cells as measured by enrichment of the OVA antigen-derived MHC class I-restricted SIINFEKL epitope-specific cells in wild-type recipients.. Interestingly, Stat1-deficient lymphoma cells (9-GFP and 9-OVA-GFP) were rejected by immunocompetent UBQ-GFP transgenic wild-type C57BL/6 mice irrespectively of the presence of a foreign antigen, indicating the existence of immunosurveillance against these Stat1-deficient lymphomas. To evaluate the key players behind lymphoma rejection, we transferred 9-GFP cells into IFN-γ-/- and Stat1-/- recipients. This led to enhanced tumor growth indicating that endogenous IFN-γ production and Stat1 signaling are critical for tumor rejection. To gain an insight into the mechanistic aspects of innate immunosurveillance against the Stat1-competent and Stat1-deficient lymphomas, NK cell functionality was evaluated. We found that NK cells could efficiently lyse both Stat1-competent and Stat1-deficient lymphoma cell lines in vitro. Treatment with IFN-γ increased the susceptibility of Stat1-deficient lymphoma cells to NK cell killing, but decreased that of Stat1-competent cells, presumably by upregulating MHC class I expression. The results of this work show that host IFN-γ and Stat1 signaling are important for tumor clearance, and that paradoxically, the absence of Stat1 within the lymphoma is required for rejection.

Background/aim: Interleukin 31 (IL31), primarily expressed in activated lymphocytes, signals through a heterodimeric receptor complex consisting of the IL31 receptor alpha (IL31Rtextgreeka) and the oncostatin M receptor (OSMR). The aim of this study was to analyse IL31 receptor expression, signal transduction, and specific biological functions of this cytokine system in intestinal inflammation.Methods: Expression studies were performed by RT-PCR, quantitative PCR, western blotting, and immunohistochemistry. Signal transduction was analysed by western blotting. Cell proliferation was measured by MTS assays, cell migration by restitution assays.Results: Colorectal cancer derived intestinal epithelial cell (IEC) lines express both IL31 receptor subunits, while their expression in unstimulated primary murine IEC was low. LPS and the proinflammatory cytokines TNF-textgreeka, IL1textgreekb, IFN-textgreekg, and sodium butyrate stimulation increased IL31, IL31Rtextgreeka, and OSMR mRNA expression, while IL31 itself enhanced IL8 expression in IEC. IL31 mediates ERK-1/2, Akt, STAT1, and STAT3 activation in IEC resulting in enhanced IEC migration. However, at low cell density, IL31 had significant antiproliferative capacities (p

Interferons are the key cytokines of innate immunity and represent the first line of defense against invading viruses. By activating immediate antiviral mechanisms and stimulating the adaptive immune response, interferon signaling is decisive for the outcome of disease and virus clearance. The work presented in this thesis reveals a central role of the phosphoprotein P of rabies virus (Rhabdoviridae family), known as a polymerase cofactor, as an inhibitor of the host interferon system. Counter-mechanism to escape form recognition by the immune system were previously unknown for the neurotropic rabies virus, which is characterized by the highest case-fatality ratio. In my work I have shown that rabies virus (strain SAD L16) is able to prevent both the production IFN-alpha/beta and the effector functions of IFN-alpha/beta and IFN-gamma. The factor responsible is the viral phosphoprotein P. P interferes with transcriptional activation of IFN-alpha/beta by preventing phosphorylation of the essential transcription factors IRF3 and IRF7 by their kinases TBK1 and IKKepsilon. Unphosphorylated IRFs are unable to dimerize and fail to enter the nucleus. In addition, rabies virus P prevents IFN-mediated JAK/STAT signaling and the expression of IFN-stimulated genes which include a broad spectrum of antiviral and immune regulatory genes. The inhibition of JAK/STAT signaling by P involves a unique mechanism, namely, specific binding of the tyrosine-phosphorylated STAT1 and STAT2 isoforms and their retention in the cytoplasm. The inhibitory activities of RV P on IFN induction and signaling are independent functions, as shown by site-directed mutagenesis of P and identification of different short amino acid stretches required for either function. Importantly, the inhibitory activities of P were demonstrated in the context of recombinant viruses. Using reverse genetics, a rabies virus was constructed, in which P expression was “knocked down” by moving the P gene to a promoter-distal position of the genome (SAD deltaPLP). This virus caused efficient IFN-alpha/beta production in infected cells and upregulation of interferon stimulated genes. The IFN sensitivity of SAD deltaPLP was confirmed in cell culture and is now being studied in animal experiments including IFN receptor knock of mice, to verify the relevance of P functions in vivo. The described work contributes to the understanding of host responses to virus infections in general and of rabies virus pathogenicity in particular. In addition, viruses with modified IFN antagonists provide interesting opportunities for development of attenuated vaccines and vectors.

Thu, 7 Oct 2004 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/2709/ https://edoc.ub.uni-muenchen.de/2709/1/Pau_Michael.pdf P

Objective: This comparative in vitro study examined the effects of all known gp130 cytokines on murine corticotroph AtT-20 cell function. Methods: Cytokines were tested at equimolar concentrations from 0.078 to 10 nM. Tyrosine phosphorylation of the signal transducer and activator of transcription ( STAT) 3 and STAT1, the STAT-dependent suppressor of cytokine signaling (SOCS)-3 promoter activity, SOCS-3 gene expression, STAT-dependent POMC promoter activity and adrenocorticotropic hormone ( ACTH) secretion were determined. Results: Leukemia inhibitory factor (LIF), human oncostatin M (OSM) and cardiotrophin (CT)-1 (LIFR/gp130 ligands), as well as ciliary neurotrophic factor ( CNTF) and novel neurotrophin1/B-cell stimulating factor-3 (CNTFRalpha/LIFR/gp130 ligands) are potent stimuli of corticotroph cells in vitro. In comparison, interleukin (IL)-6 (IL-6R/gp130 ligand) and IL-11 (IL-11R/gp130 ligand) exhibited only modest direct effects on corticotrophs, while murine OSM (OSMR/gp130 ligand) showed no effect. Conclusion: (i) CNTFR complex ligands are potent stimuli of corticotroph function, comparable to LIFR complex ligands; (ii) IL-6 and IL-11 are relatively weak direct stimuli of corticotroph function; (iii) differential effects of human and murine OSM suggest that LIFR/gp130 (OSMR type I) but not OSMR/gp130 (OSMR type II) are involved in corticotroph signaling. (iv) CT-1 has the hitherto unknown ability to stimulate corticotroph function, and (v) despite redundant immuno-neuroendocrine effects of different gp130 cytokines, corticotroph cells are preferably activated through the LIFR and CNTFR complexes. Copyright (C) 2004 S. Karger AG, Basel.

Das Epstein Barr Virus (EBV) ist ein ubiquitär vorkommendes Herpesvirus, mit dem etwa weltweit 90% der erwachsenen Bevölkerung permanent infiziert sind. Die zumeist asymptomatisch verlaufende Infektion betrifft primäre B–Zellen des Rachenraumes, die nach Aufnahme des Virus entweder zur Virus-Produktion (lytischer Zyklus) oder zur Proliferation angeregt werden (Latenzprogramm, Entstehung von B-Lymphoblasten). Letzteres wird durch den viralen Transkriptionsfaktor EBNA2 kontrolliert, der durch seine viralen und zellulären Zielgene ruhende B-Zellen in vitro immortalisieren kann. Die EBV-infizierten B-Lymphoblasten werden in vivo effizient durch T-Zellen erkannt und abgetötet. EBV entkommt der Immunantwort durch Persistenz in Gedächtnis-B-Zellen, die vermutlich durch Differenzierung der infizierten B-Lymphoblasten entstehen. Es gibt Hinweise, dass diese Differenzierung EBV-vermittelt unter der Mitwirkung von T-Helfer-Zellen abläuft, was auf eine komplexe Kommunikation des Virus mit dem Immunsystem schließen lässt. In der vorliegenden Arbeit wurden Mechanismen der EBV-vermittelten B-Zell-Immortalisierung und -Kommunikation untersucht. Ein Vergleich von EBNA2-Zielgenen mit Zielgenen des Protoonkogens c-myc, das bei Überexpression B-Zell-Proliferation induzieren kann, ermöglichte dabei die Unterscheidung von Zielgenen, die mit Proliferation und B-Zell-Kommunikation assoziiert sind. Die methodische Herangehensweise bestand in der Proteom-Analyse (2D-Gelelektrophorese mit massenspektrometrischer Proteinidentifikation), Promotoraktivitäts-Analyse (nukleärer Run-On) und einer umfassenden mRNA-Expressions-Analyse (DNA-Chip-Hybridisierung) konditional oder permanent MYC- oder EBV/EBNA2-abhängig proliferierender Zellen. Die erhaltenen Daten bestätigen, dass die von EBNA2 und MYC gemeinsam induzierten Zielgene in grundlegende Prozesse der Lebenserhaltung wie den Nukleotid-, Protein-, und Polyamin-Stoffwechsel, sowie in die oxidative Stressantwort, DNA-Reparatur und Zellteilung involviert sind. Dagegen waren gegensätzlich regulierte Gene funktionell in den Bereich B-Zell-Signaltransduktion- und B-Zell-Kommunikation einzuordnen. Die EBV-abhängige Proliferation ist sowohl mit der Aktivierung des NFkB-Signalwegs assoziiert, als auch mit der verstärkten Expression zentraler Komponenten der Interferon (IFN)-Antwort (insbesondere STAT1) und mit der Repression von Komponenten des B-Zell-Rezeptors (BCR) und der BCR-Signaltransduktion. Die NFkB-Aktivierung führt zur Induktion von antiapoptotischen Genen und von Chemoattraktoren für T-Helferzellen. Die aus Array- und Protein-Daten hervorgehende EBV/EBNA2-vermittelte Aktivierung des NFkB- und des IFN-Signalweges einerseits und die MYC-vermittelte Repression derselben andererseits könnten das molekulare Bindeglied zwischen EBV-vermittelter T-Zell-Stimulation und MYC-vermittelter Immuntoleranz darstellen. Die chemokinvermittelte T-Zell-Rekrutierung und die vermutlich durch STAT1-Expression begünstigte Antigen-präsentation weisen T-Zellen eine aktive Rolle bei der Reifung von EBV-infizierten Lymphoblasten zu B-Gedächtniszellen zu.