Podcasts about crhr1

•Intensive and chronic or excessive stress diminishes intellectual performance and general cognition: this is a form of negative reinforcement and can be related to learning disability and anxiety about future events. Indeed, •Individual responses and the magnitude of stressor as well as its association with self identity and goals will influence endurance, resilience, and self-empowerment vs. dissatisfaction and defeat. •Stresses first become recognized in the developing fetus since the fetal brain attains awareness during the first trimester and maternal stress is well established as an epigenetic mechanism involved in fetal neural development and stress is lifelong , contributing to one’s character and ability to overcome fear and anxiety. •Stress response is an element of the hypothalamic-pituitary-adrenocortical (HPA) axis where Corticotropin-releasing factor (CRF) serves as a gate keeper for fear conditioning playing dual roles as hormone and as neuromodulator. •CRH exerts multiple effects on the adult brain, often spatiotemporal, as shown by secretion site-specific responses in that CRH after binding to its GPCR's: CRHR1 and CRHR2 which subsequently regulates the formation of neuronal dendrites; neurite elongation, synaptogenesis, and circuit integration of adult-born neurons thus organizing and modifying excitatory transmission in a neuronal type-specific manner Transl Psychiatry. 2019; 9: 272. Cell Reports Oct 2019, 29, 932–945 --- Send in a voice message: https://anchor.fm/dr-daniel-j-guerra/message Support this podcast: https://anchor.fm/dr-daniel-j-guerra/support

Bronchopulmonary Dysplasia (BPD) is a form of Chronic lung disease and results from extreme pre-term birth. Systemic corticosteroid therapy is used postnatally to reduce the severity of BPD, however there is a large range in the phenotypic response to this treatment. In this episode, we speak to Tamorah Lewis, a neonatologist at Children's Mercy Hospital in Kansas City, who aimed to identify pharmacogenetic variants associated with the clinical response to systemic corticosteroid treatment. See acast.com/privacy for privacy and opt-out information.

The use of selectively bred mouse models of enhanced fear and/or anxiety-related behavior provides a unique opportunity to identify genetic targets that contribute to pathological anxiety. However, dealing with animal models needs accurate information about their phenotypes. Accordingly, high (HAB), normal (NAB) and low (LAB) anxiety-related behavior mice – a validated model of anxiety disorders - were repeatedly tested in a variety of behavioral paradigms. Whereas most tests to assess anxiety traits are based on fear of novel and open spaces, we took advantage of the inborn fear and associated avoidance of the predator odor (trimethylthiazoline (TMT)) as a measure of anxiety-related behavior. We were able to show that avoidance of TMT reflects the high anxiety phenotype of HAB mice, indicated by the decreased time animals spent in the chamber with TMT compared to NAB and LAB mice. Importantly, this result is not confounded by any deficit of the olfactory system, since mice responded to both the pleasant odor of female urine and the repugnant odor of butyric acid. To take the influence of environmental stimuli on inborn anxiety further, we next studied the impact of environmental manipulations on the genetically driven phenotype of LAB mice. Therefore, animals were exposed to a series of chronic unpredictable mild stressors (CMS). CMS-treated mice displayed increased anxiety in the TMT-avoidance test, elevated plus-maze (EPM) and light-dark box (LDB). Moreover, these animals were characterized by increased depression-like behavior and a blunted neuroendocrine regulation. Furthermore, TMT-exposure promoted a higher activation of immediate early gene expression, e.g. c-fos, in the amygdala, especially in the basolateral nuclei (BLA). c-Fos expression pattern correlated with anxiety-related behavior after CMS. Importantly, our electrophysiological studies also indicated a higher activation of amygdala in LAB mice after CMS treatment. Since corticotropin releasing hormone (CRH) is one of the most important mediators of amygdala activity and is largely involved in the regulation of the anxiety-related behavior, we hypothesized that environmental influences are translated via an altered CRH system. Previous experiments had shown that enriched environment (EE) induced a down-regulation of Crhr1. Here, we report that CMS induced higher expression of Crhr1 in the BLA of LAB mice, in contrast to EE. Thus, these data indicate, that Crhr1 expression might be plastic in response to both, beneficial and detrimental, environmental factors. Thereafter, we studied the role of DNA methylation as a probable mechanism behind the different gene expression. Using pyrosequencing of the bisulfite-converted DNA, one specific CpG site (CpG1) of Crhr1 was found to be higher methylated after both treatments. In order to evaluate functional importance of this modification, we tested the impact of CpG1 methylation on promoter activity using the luciferase assay and observed that the presence of methylation reduced promoter activity. Moreover, elevated methylation decreased the binding efficiency of the transcription factor Yin Yang 1 (YY1) as indicated by electrophoretic mobility shift assay (EMSA). Furthermore, we analyzed whether a higher expression of YY1 in the BLA of LAB mice, observed after CMS, contributed to the elevation of Crhr1. Indeed, overexpression of YY1 in the neuronal cell culture enhanced both Crhr1 expression and Crhr1 promoter activity. Finally, we estimated the effects of combininig CpG1 site-specific methylation with YY1 overexpression on Crhr1 promoter activity and tested whether in vitro overexpression of YY1 induced methylation of CpG1. Altogether, our data suggest that even a rigid genetic predisposition to low anxiety-related behavior could be rescued by environmental modification and provide evidence that the epigenetic regulation of Crhr1 expression in the BLA is a possible underlying mechanism behind.

It is becoming increasingly clear by current research that the continuum of physiological anxiety up to psychopathology is not merely dependent on genes, but is orchestrated by the interplay of genetic predisposition, gene x environment and epigenetic interactions. To consider this interplay, we here took advantage of the rigid genetic predisposition of a selectively bred mouse model exhibiting high anxiety-related behavior (HAB) and tested whether and how enriched environment, a manipulation of housing conditions, is capable of rescuing the genetically driven high anxiety phenotype via gene x environment and/or epigenetic interactions. Indeed, enriched environment exerts a significant anxiolytic effect on HABs of both sexes indicating for the first time that even a rigid genetic predisposition of high anxiety can be rescued by beneficial environmental stimuli. Thereby, a reduced neophobia and a bigger behavioral repertoire of HABs (e.g. social interactions) have been observed with a stronger anxiolysis in males than in females. The behavioral shift is accompanied by an attenuated release of corticosterone after application of a mild stressor. A hyperreactive hypothalamic-pituitary-adrenal (HPA) axis and amygdala constitute the most common symptoms of anxiety disorders, and decreased corticosterone release seems to entail a reduced release of noradrenaline from locus caeruleus (LC) to the medial prefrontal cortex (mPFC), thereby increasing the top-down control of mPFC on amygdala. This would entail less activation of amygdala and thus HPA axis, a consequence we indeed can observe as decreased neuronal activity flow through the amygdala of enriched housed (EE) compared to standard housed (SE) HABs. We suggest that corticotropin-releasing hormone receptor 1 (Crhr1) is critically involved in this phenomenon since (i) HABs compared to low anxiety-related behavior (LAB) mice exhibit higher Crhr1 mRNA in the basolateral amygdala (BLA), (ii) this overexpression can be significantly reduced when HABs are housed in enriched environment and (iii) a bilateral application of a CRHR1 antagonist in the BLA of SE HABs induced a significant anxiolytic effect. Subsequent pyrosequencing identified that enriched environment increased methylation at a CpG site in the promoter of Crhr1, which is located next to a transcription factor binding site (TFB) of the epigenetic transcription factor Yin Yang 1 (YY1), whose mRNA levels are indeed decreased in EE HABs. In silico analysis identified Nr4a1 and D3Ertd300e as critical co-transcription factors, whereas Nr4a1 seems to be regulated by the quantity of available glucocorticoid receptor (GR) and D3Ertd300e positively regulates YY1. Thus, we hypothesize that reduced corticosterone release decreases the availability and thus binding of corticosterone to GR in the BLA. This, in turn decreases the binding affinity of Nr4a1 to D3Ertd300e, which then cannot positively regulate YY1 to decrease or even prevent methylation at the identified CpG site of Crhr1. This would finally result in a differentially methylated region (DMR) with higher methylation levels in EE HABs, which underlies the observed gene expression differences. The identified DMR might therefore be used as a biomarker for high or pathological anxiety. This hypothesized mechanism highlights the possibility that even a rigid genetic predisposition modeling pathological anxiety might be rescued by an epigenetic process that seems to be triggered by beneficial environmental stimuli, thereby raising the exciting possibility for new treatment strategies, which can be utilized complementary to already existing ones.

Endometriosis is considered as a benign aseptic inflammatory disease, characterised by the presence of ectopic endometrium-like tissue. Its symptoms (mostly pain and infertility) are reported as constant stressors. Corticotropin releasing hormone (CRH) and urocortin (UCN) are neuropeptides, strongly related to stress and inflammation. The effects of CRH and UCN are mediated through CRHR1 and CRHR2 receptors which are implicated in several reproductive functions acting as inflammatory components. However, the involvement of these molecules to endometriosis remains unknown. The aim of this study was to examine the expression of CRHR1 and CRHR2 in endometriotic sites and to compare the expression of CRHR1 and CRHR2 in eutopic endometrium of endometriotic women to that of healthy women. We further compared the expression of CRH, UCN, CRHR1 and CRHR2 in ectopic endometrium to that in eutopic endometrium of women with endometriosis. Endometrial biopsy specimens were taken from healthy women (10 patients) and endometrial and endometriotic biopsy specimens were taken from women with endometriosis (16 patients). Τhe expression of CRH, UCN, CRHR1, and CRHR2 was tested via RT-PCR, immunohistochemistry and Western blotting. This study shows for the first time that CRH and UCN receptor subtypes CRHR1β and CRHR2α are expressed in endometriotic sites and that they are more strongly expressed (p

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is a hallmark of complex and multifactorial psychiatric diseases such as anxiety and mood disorders. The 41-amino acid neuropeptide Corticotropin Releasing Hormone (CRH) is a major regulator of the mammalian stress response. Upon stressful stimuli, it binds to the Corticotropin Releasing Hormone Receptor 1 (CRHR1), a typical member of the class B GPCRs and a potential novel target for the therapeutic intervention in major depressive disorder. A precise understanding of the peptide-receptor interactions is an essential prerequisite towards the development of efficient CRHR1 specific antagonists. To chemically probe the molecular interaction of CRH with its cognate receptor, a high-throughput conjugation approach which mimics the natural activation mechanism for class B GPCRs was developed. Acetylene-tagged peptide libraries were synthesized and conjugated to high-affinity azide-modified carrier peptides using copper-catalyzed dipolar cycloaddition. The resulting conjugates reconstitute potent ligands and were tested in situ for modulation of the CRHR1 activity in a cell-based assay. This approach allows to (i) define the sequence motifs which are required for receptor activation or inhibition, (ii) identify the critical functional groups and investigate structure-activity-relationships, and (iii) develop novel optimized, highly potent peptide probes which are specific for the transmembrane domain of the receptor. The membrane recruitment by a high-affinity carrier peptide enhances the potency of tethered peptides and allows the initial testing of weak fragments that otherwise would be inactive. The biomimetic screening led to the discovery of transtressin, a highly modified and potent CRHR1 transmembrane domain-specific optimized agonist (EC50 = 4 nM). Beyond its intrinsic agonistic activity, transtressin is an essential tool for the pharmacological characterization of CRHR1 antagonists in competition assays.

The corticotropin-releasing hormone (CRH) is widely recognised as the major activator of the hypothalamic-pituitary-adrenocortical (HPA) axis, thereby mediating neuroendocrine, autonomic, and behavioural responses to stress. Dysregulation of the release of stress hormones, caused by excessive CRH secretion from the hypothalamus, is frequently observed in patients with affective disorders such as depression. One of the cardinal symptoms of major depression is a severe impairment of sleep (e.g. reduced sleep intensity, disinhibition of rapid eye movement sleep (REMS), and early morning awakenings). Consequently, besides a role of CRH in stress-induced arousal, its additional contribution to spontaneous sleep-wake regulation was suggested in literature. Due to the lack of highly specific CRH receptor antagonists and adequate CRH receptor knockout animal models, the mechanism and pathways by which CRH communicates its arousal function remained indistinct. Up to now it is unclear whether CRH interferes with sleep by a direct central action, or if the activation of the HPA axis and the subsequent release of peripheral stress hormones are mandatory. The present study with conditional CNS-specific CRH receptor type 1 (CRH-R1 CKO) and conventional CRH receptor type 2 knockout mice (CRH-R2 KO), allows assessment of CRH effects on wakefulness and sleep separately from a functional HPA axis together with various levels of CRH receptor system functionality. In addition, challenging sleep homeostasis in these mouse lines by sleep deprivation allows investigating the involvement of CRH and its receptor system in basic sleep-wake regulatory processes. Besides slight dissimilarities between the baseline sleep profiles in the various genotypes, CRH-R1 CKO displayed a markedly different response to intracerebroventricular (i.c.v.) CRH injections. The dose-dependent increases in wakefulness and decreases in non-REM sleep (NREMS), which could be observed in all other mouse lines, were almost totally absent in CRH-R1 CKO. The dose-dependent REMS suppression on the other hand persisted in all, even CRH-R1 CKO, animals. This suggests that the centrally expressed CRH receptor type 1 (CRH-R1) but not the CRH receptor type 2 (CRH-R2), mediates the crucial effects of CRH on wake induction and NREMS suppression. Since REMS inhibition by CRH still occurred in CRH-R1 CKO animals pretreated with a highly specific CRH-R2 antagonist, the clear role of central CRH and both receptors in REMS suppression remains elusive. Sleep deprivation induced significant increases in plasma corticosterone levels in all mouse lines, demonstrating HPA axis activation and suggesting that all mice perceived sleep loss as a stressor. After termination of sleep deprivation, all animals responded with a significant increase of slow wave activity (SWA), an indicator of sleep intensity, followed by a rebound of NREMS. With the exception of CRH-R1 CKO mice, all mice furthermore similarly displayed REMS rebound. Another difference in response to sleep deprivation constitutes the course of SWA in CRH-R1 CKO which was significantly increased over baseline levels for a longer period as compared to all other mouse lines. Accordingly CRH-R1 CKO animals presumably sleep more intensely or efficiently than mice of the other breeding lines. These results suggest that CRH mediates the effects, at least the stressful component, of sleep loss, and moreover that CRH-R1 is essentially involved in sleep homeostasis. This study is the first to show considerable evidence for a crucial involvement of central CRH and CRH-R1 in arousal and the suppression of NREMS. It could further be shown that activation of the HPA axis is not a prerequisite of these effects. Additionally, the action of central CRH, mediated by CRH-R1 seems to influence sleep quality. The role of CRH-R2 has to be regarded as of a minor nature. The impact of CRH on REMS regulation demands further investigation.

Neben den klassischen kardiovaskulären Risikofaktoren wie arterielle Hypertonie oder Hypercholesterinämie kommen den psychosozialen Faktoren wie Stress oder Depression eine entscheidene Rolle als Risikofaktor für die Entwicklung der Atherosklerose zu. Obwohl das chronische Stresshormon Corticotropin-Releasing-Hormon im Rahmen der adaptiven Stressantwort als Hauptvertreter der Effektorhormone angesehen wird, sind die pathophysiologischen Mechanismen, die zu einer CRH/Stress-bedingten endothelialen Dysfunktion führen, weitgehend unbekannt. Diese Arbeit hatte zum Ziel, den Effekt von peripherem CRH auf die Monozyten/Endothel-Interaktion, beispielhaft die Adhäsion, herauszuarbeiten. Die Untersuchungen der Monozyten-Endothel-Adhäsion wurde in einem in-vitro-Modell unter Verwendung der Zelllinien HMEC-1 und THP-1 mit einer neuen, modifizierten fluorometrischen Methode untersucht, monozytäres MAC-1/CD11b, endotheliales ICAM-1/CD54 und VCAM-1/CD106 mit Hilfe der Durchflusszytometrie bestimmt. Der Nachweis der vermittelnden monozytären CRH-Rezeptoren R1/-R2 erfolgte mittels RT-PCR- und Immunfluoreszenztechnik. THP-1 konnte als Zielzelle für CRH mit Nachweis der CRH-Rezeptoren auf mRNA- und Proteinebene identifiziert werden. CRH induzierte eine signifikante zeit- und konzentrationsabhängige Adhäsionszunahme der THP-1 Zellen am HMEC-1 Monolayer. Der Effekt scheint Monozyten-vermittelt, da CRH, konzentrationsabhängig, zu einer monozytären MAC-1/CD11b-Freisetzung führte. Eine CRH-Stimulation nur von HMEC-1 führte hingegen zu keiner Adhäsionszunahme, erklärbar z. B. durch die hier dokumentierte fehlende Veränderung von endothelialem ICAM-1/CD54 und VCAM-1/CD106 unter Einfluß von CRH. Die Ergebnisse unterstreichen somit die Relevanz von peripherem CRH auf die Monozytenfunktion und Monozyten/Endothel-Interaktion. Sie können einen Beitrag zur Erklärung eines möglichen Zusammenhangs von chronischem Stress (mit konsekutiver Erhöhung des Stresshormons CRH) und der Initiation / Progression der endothelialen Dysfunktion leisten (Wilbert-Lampen, Straube et al., 2006).

This work investigates for the first time the expression and the role of Sonic hedgehog signaling pathway in adult pituitary and in pituitary tumors. Shh is a signaling protein, important in regulating patterning and proliferation in the embryo and the adult. It has a crucial role in pituitary development and Shh deficient mice do not even have a rudimentary Rathke's pouch (the development structure that gives rise to anterior pituitary). This study reveals the presence of an active Shh pathway in the post-developmental pituitary gland, with major impacts on hormone secretion and cell proliferation. After embryonic development, Shh continues to be expressed in the normal adult pituitary, being mainly co-localized in corticotrophs. These cells express also the receptor Ptc2 and the Shh induced transcription factor Gli1, being so Shh-producing and Shh-responsive cells. Shh acts in an autocrine way inside corticotrophs, inducing a major stimulation of ACTH secretion in the normal rat pituitary and in the AtT-20 cell line. The Shh induced ACTH secretion effect is synergistic with CRH. Shh stimulation increases CRH-R1 levels, up-regulating so the response of corticotrophs to CRH. At the same time, Gli1 is not only activated by Shh, but also by CRH and PKA. Gli1 itself activates POMC-transcription and acts in parallel upstream to CREB and AP-1. A major increase in Shh protein levels is seen as a result of CRH stimulation. All these results put in evidence a multiple cross-talk between these two important pathways acting at different levels to insure the final ACTH stimulation. Other types of hormone-secreting adenohypophysial cells possess one of Shh receptors (Ptc1 or Ptc2) and the transcription factor Gli1, so they have an active Shh pathway. Shh produced in the corticotrophs is a signaling protein, so it diffuses and acts also in distance. Shh increases GH secretion from the rat pituitary somatotrophs and from the GH3 cell line, while the effect on Prolactin is not statistically significant. The Sonic hedgehog pathway is downregulated in pituitary adenomas. Screening of 55 pituitary tumors reveals that they have a significantly reduced expression of Shh and Gli1. Although Shh in the normal pituitary is secreted by corticotroph cells, all the Cushing tumors screened had no Shh expression at all. Cell culture experiments performed in the AtT-20 corticotroph cell line in vitro show that Shh reduces cell proliferation by 50% and this effect is partially reducible by Cyclopamine. So Shh maintains the low proliferative capacity of corticotrophs in the normal pituitary gland and its loss may be one of the factors leading to tumor progression. It is concluded that Shh is produced in the anterior pituitary gland, is a major stimulant of ACTH and GH secretion, acts synergistically with CRH, opposes corticotroph cell proliferation and is downregulated in pituitary adenomas.