CRF1 Research Articles

Hypothalamic-Pituitary-Adrenal Hormones Impair Pig Fertilization and Preimplantation Embryo Development via Inducing Oviductal Epithelial Apoptosis: An In Vitro Study.

Previous studies show that stressful events after ovulation in sows significantly impaired the embryo cleavage with a significant elevation of blood cortisol. However, the effects of corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol on fertilization and embryo development remain to be specified, and whether they damage pig embryos directly or indirectly is unclear. This study demonstrated that embryo development was unaffected when pig parthenotes were cultured with different concentrations of CRH/ACTH/cortisol. However, embryo development was significantly impaired when the embryos were cocultured with pig oviductal epithelial cells (OECs) in the presence of CRH/cortisol or cultured in medium that was conditioned with CRH/cortisol-pretreated OECs (CRH/cortisol-CM). Fertilization in CRH/cortisol-CM significantly increased the rates of polyspermy. CRH and cortisol induced apoptosis of OECs through FAS and TNFα signaling. The apoptotic OECs produced less growth factors but more FASL and TNFα, which induced apoptosis in embryos. Pig embryos were not sensitive to CRH because they expressed no CRH receptor but the CRH-binding protein, and they were tolerant to cortisol because they expressed more 11-beta hydroxysteroid dehydrogenase 2 (HSD11B2) than HSD11B1. When used at a stress-induced physiological concentration, while culture with either CRH or cortisol alone showed no effect, culture with both significantly increased apoptosis in OECs. In conclusion, CRH and cortisol impair pig fertilization and preimplantation embryo development indirectly by inducing OEC apoptosis via the activation of the FAS and TNFα systems. ACTH did not show any detrimental effect on pig embryos, nor OECs.

Local production of corticotropin-releasing hormone in prefrontal cortex modulates male-specific novelty exploration

Neuromodulatory substances can be released from distal afferents for communication between brain structures or produced locally to modulate neighboring circuit elements. Corticotropin-releasing hormone (CRH) from long-range neurons in the hypothalamus projecting to the medial prefrontal cortex (mPFC) has been shown to induce anxiety-like behaviors. However, the role of CRH produced in the mPFC has not been investigated. Here we demonstrate that a specific class of mPFC interneurons that express CRH (CrhINs) releases CRH upon high-frequency stimulation to enhance excitability of layer 2/3 pyramidal cells (L2/3 PCs) expressing the CRH receptors. When stimulated at low frequency, CrhINs release GABA resulting in the inhibition of oxytocin receptor-expressing interneurons (OxtrINs) and L2/3 PCs. Conditional deletion of CRH in mPFC CrhINs and chemogenetic activation of CrhINs have opposite effects on novelty exploration in male but not in female mice, and do not affect anxiety-related behaviors in either males or females. Our data reveal that CRH produced by local interneurons in the mPFC is required for sex-specific novelty exploration and suggest that our understanding of complex behaviors may require knowledge of local and remote neuromodulatory action.

The CRHR1/CREB/REST signaling cascade regulates mammalian embryonic neural stem cell properties.

Growing evidence suggests that the corticotropin-releasing hormone (CRH) signaling pathway, mainly known as a critical initiator of humoral stress responses, has a role in normal neuronal physiology. However, despite the evidence of CRH receptor (CRHR) expression in the embryonic ventricular zone, the exact functions of CRH signaling in embryonic brain development have not yet been fully determined. In this study, we show that CRHR1 is required for the maintenance of neural stem cell properties, as assessed by invitro neurosphere assays and cell distribution in the embryonic cortical layers following in utero electroporation. Identifying the underlying molecular mechanisms of CRHR1 action, we find that CRHR1 functions are accomplished through the increasing expression of the master transcription factor REST. Furthermore, luciferase reporter and chromatin immunoprecipitation assays reveal that CRHR1-induced CREB activity is responsible for increased REST expression at the transcriptional level. Taken together, these findings indicate that the CRHR1/CREB/REST signaling cascade plays an important role downstream of CRH in the regulation of neural stem cells during embryonic brain development.

Tripartite extended amygdala–basal ganglia CRH circuit drives locomotor activation and avoidance behavior

An adaptive stress response involves various mediators and circuits orchestrating a complex interplay of physiological, emotional, and behavioral adjustments. We identified a population of corticotropin-releasing hormone (CRH) neurons in the lateral part of the interstitial nucleus of the anterior commissure (IPACL), a subdivision of the extended amygdala, which exclusively innervate the substantia nigra (SN). Specific stimulation of this circuit elicits hyperactivation of the hypothalamic-pituitary-adrenal axis, locomotor activation, and avoidance behavior contingent on CRH receptor type 1 (CRHR1) located at axon terminals in the SN, which originate from external globus pallidus (GPe) neurons. The neuronal activity prompting the observed behavior is shaped by IPACLCRH and GPeCRHR1 neurons coalescing in the SN. These results delineate a previously unidentified tripartite CRH circuit functionally connecting extended amygdala and basal ganglia nuclei to drive locomotor activation and avoidance behavior.

Correlation Between Sleep Electroencephalogram, Brain-Derived Neurotrophic Factor, AVPR1B Gene Polymorphism, and Suicidal Behavior in Patients with Depression.

The purpose of this article was to investigate the level of serum brain-derived neurotrophic factor and its relationship with suicidal symptoms and severity in mentally ill suicide attempt patients, and to explore the possible role of serum brain-derived neurotrophic factor (BDNF) in the occurrence of psychotic suicidal behavior. A retrospective analysis was performed on patients with depression in the neurology department of a hospital. General physical examination, neurological specialist examination, and cranial magnetic resonance imaging (MRI) examination were performed on any selected group. We applied the 24-item Hamilton Depression Scale, Hamilton Anxiety Scale, and Mini-Intelligence Mental State Scale, and performed polysomnography and electroencephalography (EEG) monitoring to conduct statistical analysis on sleep indicators. The amplitude of low-frequency fluctuation (ALFF) values of the right frontal gyrus, left posterior cerebellar lobe, right anterior cerebellar lobe, and right occipital lingual gyrus of the patient group were significantly lower than those of the control group. The ReHo values of the right superior parietal lobule, the left precuneus, and the right occipital lingual gyrus were significantly higher than those of the control group. The genotype and allele frequency distribution of FKBP5, AVPR1B, and CRHR2 gene SNPs had no significant difference between the case group and the control group (P > 0.05). The ReHo value of the precuneus is significantly correlated with the proportion of N3 sleep, and the dysfunction of the precuneus or default network may be related to the altered sleep structure in patients with depression. The GT and TT genotypes at rs9324924 of the NR3C1 gene are associated with suicide attempts.

Mast Cell Specific Receptor Mrgprb2 Regulating Experimental Colitis is Associated with the Microbiota-Gut-Brain Axis.

Ulcerative colitis (UC) patients have disturbances in the microbiota-gut-brain axis, and mast cells are important components of this axis. The mast cell-specific receptor Mrgprb2 has effects on host defense against bacterial infection and neurogenic inflammation, which may help mast cells act on the axis. This study analyzed how Mrgprb2 participates in the pathogenesis of UC by affecting the microbiota-gut-brain axis. Mrgprb2 knockout (b2KO) mice and wild-type (WT) mice were fed 2% (w/v) dextran sulfate sodium (DSS) in drinking water for 7 days, which was then replaced with normal water for 14 days. This cycle was repeated three times. Feces were collected on Days 21, 42, and 63 for intestinal microbiota analysis, and mice were euthanized on Day 64. Hypothalamus, amygdala and colon tissues were removed and analyzed. Compared with WT mice, B2KO mice exhibited increased weight loss, colon shortening and colonic pathological damage after colitis induction. Analysis of the intestinal microbiota showed that b2KO mice with colitis had a significant decrease in the abundance and diversity, as well as an increase in Allobaculum and a decrease in norank_f__Muribaculaceae and Ileibacterium. In colon tissues, the expression of mucin 2 (MUC2) and junctional adhesion molecule A (JAM-A) in b2KO mice was reduced, and oxidative stress levels were higher. B2KO mice with colitis had higher corticotropin-releasing hormone (CRH), corticotropin-releasing hormone receptor 1 (CRHR1), neuropeptide Y (NPY) and brain-derived neurotrophic factor (BDNF) mRNA levels in hypothalamus tissues and glucocorticoid receptor mRNA levels in the amygdala. In the microbiota-gut-brain axis, Mrgprb2 was involved in regulating the intestinal microbiota composition, intestinal barrier and oxidative stress levels, and was related to stress regulation, which might help to explain the pathogenesis of UC.

ODP335 Mutual Effects of Orexin and BMPs on Gonadotropin Expression by Mouse Gonadotrope LβT2 Cells

Abstract Orexins are neuropeptides that express primarily in the hypothalamus and are produced in two isoforms, orexin A and orexin B. There are two kinds of G protein coupled receptors, orexin type 1 (OX1R) and type 2 (OX2R) receptors. Orexin has been reported to have key roles on sleep-wake regulation and feeding behavior in the central nervous system, whereas its receptors are also expressed in peripheral tissues including the endocrine organs, and orexin affects the regulation of the endocrine system. In our previous experiments, we have revealed the impact of orexins on anterior pituitary functions. For instance, we reported that orexin A plays an inhibitory role in prolactin production through the suppression of endogenous bone morphogenetic protein (BMP) activity in rat pituitary lactotrope GH3 cells. It was also reported that orexin A enhances pro-opiomelanocortin (POMC) transcription by upregulating corticotropin-releasing hormone (CRH) receptor signaling and by downregulating BMP-Smad signaling in mouse corticotope AtT20 cells. However, the effects of orexin on the endocrine function regarding gonadotrope cells remain unclear. We have recently uncovered that core clock genes and BMPs have mutual effects on luteinizing hormone (LH) expression in a phase-dependent manner by mouse gonadotrope LβT2 cells. In the present study, we investigated the effect of orexin on pituitary gonadotropin expression using LβT2 cells, which express OX1R and OX2R, by focusing on the functional involvement of BMP system and clock genes. It was revealed that orexin A stimulation increased LHβ and FSHβ mRNA expression in a concentration-responsive manner in the absence of GnRH, and interestingly, GnRH co-treatment further upregulated LHβ mRNA expression in LβT2 cells. Regarding the interrelationships between the signalings of orexin and BMPs, it was also revealed that orexin A pretreatment enhanced the BMP receptor signaling detected as the Smad1/5/9 phosphorylation, indicating that orexin enables to upregulate the BMP actions in LβT2 cells. In our previous studies, we reported that several BMP ligands such as BMP-6, -7 and 15 expressed in LβT2 cells can promote gonadotropin transcription, in which BMP-6 regulates GnRH-stimulated LH expression by modulating the sensitivity to somatostatin analogs. Based on the present results, it was implied that endogenous orexin can be functionally involved in the underlying mechanisms of gonadotropin expression. Collectively, orexin enhances gonadotropin expression by regulating BMP signaling in gonadotrope cells. Here, we will also discuss functional involvement of clock genes in the regulatory system of gonadotropin secretion induced by orexin and BMPs. Presentation: No date and time listed

Transcriptome of pituitary function changes in rat model of high altitude cerebral edema

High altitude cerebral edema (HACE) is a serious subtype of acute mountain sickness (AMS). Studies have suggested that increased expression of corticotropin releasing hormone receptor 1 (CRFR1) in pituitary is related to the development of HACE, but no study has revealed the molecular landscape of pituitary function changes in this process. Rat model of HACE was established by simulating the high-altitude hypobaric hypoxia environment. Then RNA-sequencing was performed of rat pituitary gland (PG) in HACE and non-HACE groups. The function annotations, enrichment analysis, protein–protein interaction (PPI) network, chromosome location and drug repositioning of differentially expressed genes (DEGs) were explored based on the transcriptomic data. And we found pituitary secretion function was disordered in HACE, which was partly due to activated inflammation and oxidative stress. In addition, we identified potential biomarkers for early recognition of pituitary dysfunction and potential protective drugs for pituitary function in HACE.

Identification of MRAP protein family as broad-spectrum GPCR modulators.

The melanocortin receptor accessory proteins (MRAP1 and MRAP2) are well-known endocrine regulators for the trafficking and signalling of all five melanocortin receptors (MC1R-MC5R). The observation of MRAP2 on regulating several non-melanocortin G protein-coupled receptors (GPCRs) has been sporadically reported, whereas other endogenous GPCR partners of the MRAP protein family are largely unknown. Here, we performed single-cell transcriptome analysis and drew a fine GPCR blueprint and MRAPs-associated network of two major endocrine organs, the hypothalamus and adrenal gland at single-cell resolution. We also integrated multiple bulk RNA-seq profiles and single-cell datasets of human and mouse tissues, and narrowed down a list of 48 GPCRs with strong endogenous co-expression correlation with MRAPs. 36 and 46 metabolic-related GPCRs were consequently identified as novel interacting partners of MRAP1 or MRAP2, respectively. MRAPs exhibited protein-protein interactions and varying pharmacological properties on the surface translocation, constitutive activities and ligand-stimulated downstream signalling of these GPCRs. Knockdown of MRAP2 expression by hypothalamic administration of adeno-associated virus (AAV)packed shRNA stimulated body weight gain in mouse model. Co-injection of corticotropinreleasing factor (CRF), the agonist of corticotropin releasing hormone receptor 1 (CRHR1), suppressed feeding behaviour in a MRAP2-dependent manner. Collectively, our study has comprehensively elucidated the complex GPCR networks in two major endocrine organs and redefined the MRAP protein family as broad-spectrum GPCR modulators. MRAP proteins not only serve as a vital endocrine pivot on the regulation of global GPCR activities in vivo that could explain the composite physiological phenotypes of the MRAP2 null murine model but also provide us with new insights of the phenotyping investigation of GPCR-MRAP functional complexes.

Interaction between the hypothalamo-pituitary-adrenal and thyroid axes during immobilization stress.

The location of corticotropin-releasing hormone receptor 2 (CRH-R2) on thyrotropes within the avian anterior pituitary (APit) and its activation by different stressors indicate a possible communication between hypothalamo-pituitary-adrenal (HPA) and thyroid (HPT) axes. Therefore, an experiment was designed to 1) compare the timing of major components of the HPT axis to those of the HPA axis; 2) address whether stressors activating the HPA axis may simultaneously upregulate components of the HPT axis. Blood, brain, and APit were sampled from chicks prior to stress (control) and 15, 30, 60, 90, and 120min following immobilization (IM) stress. The nucleus of the hippocampal commissure (NHpC) and paraventricular nucleus (PVN) were cryo-dissected from brains for RT-qPCR. Gene expression of thyrotropin-releasing hormone (TRH) and its receptors (TRH-R1 and TRH-R3), urocortin3 (UCN3), deiodinase 2 (D2), and the second type of corticotropin-releasing hormone (CRH2) within the NHpC and PVN was measured. Additionally, gene expression of TRH receptors, thyroid stimulating hormone subunit beta (TSHβ), and D2 was determined in the APit and corticosterone assayed in blood. In brains, a significant upregulation in examined genes occurred at different times of IM. Specifically, UCN3 and CRH2 which have a high affinity to CRH-R2 showed a rapid increase in their mRNA levels that were accompanied by an early upregulation of TRHR1 in the NHpC. In the APit, a significant increase in gene expression of TSHβ and TRH receptors was observed. Therefore, results supported concurrent activation of major brain and APit genes associated with the HPA and HPT axes following IM. The initial neural gene expression originating within the NHpC resulted in the increase of TSHβ mRNA in the APit. Specifically, the rapid upregulation of UCN3 in the NHpC appeared responsible for the early activation of TSHβ in the APit. While sustaining TSHβ activation appeared to be due to both CRH2 and TRH. Therefore, data indicate that CRH-producing neurons and corticotropes as well as CRH- and TRH-producing neurons and thyrotropes are activated to produce the necessary energy required to maintain homeostasis in birds undergoing stress. Overall, data support the inclusion of the NHpC in the classical avian HPA axis and for the first time show the concurrent activation of the HPA axis and components of the HPT axis following a psychogenic stressor.

Experiences Shape Hippocampal Neuron Morphology and the Local Levels of CRHR1 and OTR.

The dorsal hippocampus is involved in behavioral avoidance regulation. It is unclear how experiences such as the neonatal stress of maternal deprivation (MD) and post-weaning environmental enrichment (EE) affect avoidance behavior and the dorsal hippocampal parameters, including neuronal morphology, corticotrophin-releasing hormone (CRH) signaling, and oxytocin receptor (OTR) level. In male BALB/c mice, we found that MD impaired avoidance behavior in the step-on test compared to non-MD and EE rearing conditions could alleviate that partially. MD increased neuronal branches in the CA1 but decreased synaptic connection levels in the CA2, CA3, and DG. Meanwhile, MD increased the CA1's OTR levels, which negatively correlated with nucleus densities. MD also increased the CA1's and CA2's CRH levels, which positively correlated with CRHR1 levels. However, MD statistically elevated the CA3's CRH receptor 1 (CRHR1) levels, which negatively correlated with nucleus densities and, probably, synaptic connection levels in the CA3. The additive effects of MD and EE maintained similar CRH levels and CRHR1 levels as well as OTR levels in the hippocampal areas as the additive of non-MD and non-EE. However, the presence of MD and EE still decreased the CA1's neuronal branches and the CA2's and DG's synaptic connection levels. The study illustrates how MD and EE affect avoidance behaviors, hippocampal neuron morphology, and CRH and OTR levels. The results indicate that the late-life environmental improvement partially restores the alterations in dorsal hippocampal areas induced by early life stress.

Effect of Vitamin D3 Treatment on Genes Expression of Corticotrophin Releasing Hormone (CRH), CRH Receptor 1 (CRH-R1) and Connexin-43 (CON-43) in PHM1-41 Cell Line that Induced by Hypoxia

Introduction: Hypothalamic-Pituitary-Adrenal (HPA) axis activity is one of pathophysiologic mechanism that caused preterm labor. Biologic maternal stress, for instance hypoxia condition, is one of the causes that can trigger preterm birth occasion through the activation of HPA axis. It increases Corticotrophin Releasing Hormone (CRH), CRH receptor 1 (CRH-R1), and Connexin-43 (CON-43) as the trigger of the contraction process. Vitamin D as a source of Ca2+ ion is needed for myometrium smooth muscle’s concentrations and relaxation mechanism. The aim of this study was to determine the effect of vitamin D3 in PHM1-41 cell line. Materials and Methods: The human smooth muscle uterine myometrium cell line PHM1-41 as an in vitro model experimental subject, treated by hypoxia oxidative stress condition and added by vitamin D3 (5, 10, 50 and 150 nM). The dichlorodihydrofluorescein diacetate (DCFDA) fluorescent was used to measure the level of intracellular reactive oxygen species (ROS). In addition, RNA of treated PHM1-41cells was isolated for analyzing gene expressions such as CRH, CRH-R1, and CON-43 as a profile of contractility regulation. Results: ROS level effectively decrease in the cells that treated by 150 nM vitamin D3 group compared to the control hypoxia cell group (7.16 ± 0.23 and 19.49 ± 1.76, respectively). Expression of CRH, CRH-R1, and CON-43 genes are also decrease by treated with 150 nM vitamin D3 to the cells. Pearson (parametric) correlation analysis evidenced a negative correlation between the vitamin D3 additional treated to the lower of ROS level, CRH, CRH-R1, and CON-43 genes expression on PHM1-41 cell line that induced by oxidative stress condition. Conclusion: The concentration of 150 nM vitamin D3 was a prominent potency to prevent the incidence of preterm labor.
 HIGHLIGHTS
 
 Hypothalamic-Pituitary-Adrenal (HPA) axis is one of the causes of preterm birth that marked by high level of intracellular ROS leads to increasing of Corticotrophin Releasing Hormone (CRH) which has significant role in aterm and preterm labor
 PHMI-41 cells can describe the Corticotrophin Releasing Hormone (CRH), CRH receptor 1 (CRH-R1), and Connexin-43 (CON-43) genes expression level so it was used as model of human pregnancy condition
 Vitamin D3 is one of antioxidant agent that can decrease ROS level also CRH, CRH-R1, and CON-43 genes expression on PHM1-41 cell especially at doses of 150 nM which shown a prominent potency to prevent the preterm labor incidence
 
 GRAPHICAL ABSTRACT

Early-life maternal deprivation affects the mother-offspring relationship in domestic pigs, as well as the neuroendocrine development and coping behavior of piglets.

Early-life adversity may have programming effects on the psychological and physiological development of offspring. Domestic pigs (Sus scrofa) are an excellent model species for studying these effects because of their many physiological similarities to humans. Piglets from 10 sows were subjected to daily 2-h maternal deprivation on postnatal days (PND) 2–15 alone (DA) or in a group of littermates (DG). Control piglets (C) from 10 sows stayed with their mothers. Mother-offspring interaction, milk oxytocin, and cortisol were analyzed. An open-field/novel-object (OF/NO) test was performed with piglets on PNDs 16 and 40. Plasma cortisol and immune parameters were determined on PND 5 and 16. Two piglets from each group and sow were sacrificed on PND 20 and stress-related gene expression in the limbic system and prefrontal cortex (PFC), as well as splenic lymphocyte proliferative abilities, were examined. The milk cortisol of sows increased during the first separation of mother and offspring on the second day of lactation, whereas milk oxytocin did not change. The increase in cortisol by the OF/NO test on PND 16 was greater in C piglets than in DA and DG ones. DA piglets showed less agitated behavior than DG and C piglets in the OF/NO test at PND 16, but appeared more fearful. On PND 40, DA piglets showed more arousal than DG and C piglets in the OF/NO test. Neither plasma IgA nor N/L ratios in blood nor mitogen-induced proliferation of spleen lymphocytes were affected by deprivation. We found a higher mRNA expression of CRHR1 in the hypothalamus and a higher expression of MR in the hippocampus in DA piglets than in DG ones. The expression of GR, MR, and CRHR1 genes in the PFC was reduced by maternal deprivation, however, the expression of arginine vasopressin and oxytocin receptors was not affected. Repeated maternal deprivation induces sustained effects on stress reactivity and behavior of domestic piglets. Some of these effects were buffered by the presence of littermates. In addition, we found sex-specific differences in behavior and gene expression.

Using a Rat Model to Translate and Explore the Pathogenesis of Ketamine-Induced Cystitis

Purpose: Ketamine abusers may develop severe ulcerative cystitis along with irritative bladder symptoms. A reliable animal model may benefit the understanding of pathophysiologies and the development of therapeutic strategies for ketamine-induced cystitis (KIC). We used a popular rat model of KIC to validate the micturition behavior, functional brain images, and possible molecular mechanisms of this model. Materials and Methods: Female Sprague–Dawley rats were distributed to control (saline) and ketamine-treated rats (25 mg/kg/day for 28 days). Functional magnetic resonance imaging (fMRI), metabolic cage study, and cystometry were evaluated. Potential bladder transcripts involved in KIC were screened by using next-generation sequencing. Results: In contrast to the control, the ketamine-treated rats developed bladder overactivity accompanied by enhanced fMRI signals in periaqueduct and caudal putamen areas. Alterations in bladder transcripts, including eleven genes involving in regulating NF-κB signaling of bladder inflammation, and Crhr2 gene overexpression associating with vascular endothelial growth factor signaling of bladder ischemia were found in ketamine-treated rats. Both categories could be attributed to neurogenic inflammation induced by the direct toxicity of urinary ketamine and its metabolites. Conclusion: Our study results suggest this animal model could mimic irritative bladder symptoms associated with central sensitization in KIC. Through the bladder transcripts analysis, we highlight the neurogenic inflammation underlying the pathophysiologies of KIC in rats.

Comparison of the chronic unpredictable mild stress and the maternal separation in mice postpartum depression modeling

Postpartum depression (PPD) is a serious mental health concern of new mothers worldwide. In view of the particularity of puerpera, the research on pathogenesis and drug development of PPD are highly dependent on animal models. Although both maternal separation (MS) and chronic unpredictable mild stress (CUMS) modeling approaches have been used in PPD studies, the characteristics of the two rodent models have not been compared to explain which is more advantageous in PPD research. In this study, we applied 21-day MS and CUMS paradigms to induce mouse model of PPD and compared their differences in behavior, physiology and gut microbiota. As a result, the two models exhibited significant increases of immobility time in forced swim test (FST) and tail suspension test (TST), whereas sucrose preference index and pup weight were significantly decreased. Both displayed depression-like behaviors, and CUMS was more obvious, which demonstrated by the lower levels of 5-hydroxytryptamine (5-HT) and higher hypothalamic-pituitary-adrenal (HPA) axis related mRNA expression (corticotropin releasing hormone, corticotropin releasing hormone receptor 1) in CMUS group than that in MS group. The gut microbiota in MS and CUMS groups were significantly different in terms of the relative abundances of Bacteroidetes, Firmicutes, Proteobacteria. In conclusion, MS model and CUMS model have different performance in behavior and physiology. The CUMS model showed more obvious parameter changes, which may be more suitable for PPD induced by various social environmental factors.

Necroptosis Contributes to LPS-Induced Activation of the Hypothalamic-Pituitary-Adrenal Axis in a Piglet Model.

Stressors cause activation of the hypothalamic-pituitary-adrenal (HPA) axis and a systemic inflammatory response. As a newly proposed cell death manner in recent years, necroptosis occurs in a variety of tissue damage and inflammation. However, the role of necroptosis in HPA axis activation remains to be elucidated. The aim of this study was to investigate the occurrence of necroptosis and its role in HPA activation in a porcine stress model induced by Escherichia coli lipopolysaccharide (LPS). Several typical stress behaviors like fever, anorexia, shivering and vomiting were observed in piglets after LPS injection. HPA axis was activated as shown by increased plasma cortisol concentration and mRNA expression of pituitary corticotropin-releasing hormone receptor 1 (CRHR1) and adrenal steroidogenic acute regulatory protein (StAR). The mRNA expression of tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β) and IL-6 in the hypothalamus, pituitary gland and adrenal gland was elevated by LPS, accompanied by the activation of necroptosis indicated by higher mRNA expression of necroptosis signals including receptor-interacting protein kinase (RIP) 1, RIP3, and phosphorylated mixed-lineage kinase domain-like protein (MLKL). Furthermore, necrostatin-1 (Nec-1), an inhibitor of necroptosis, inhibited necroptosis indicated by decreased mRNA levels of RIP1, RIP3, MLKL, and phosphoglycerate mutase family member 5 (PGAM5) in the hypothalamus, pituitary gland and adrenal gland. Nec-1 also decreased the mRNA expression of TNF-α and IL-β and inhibited the activation of the HPA axis indicated by lower plasma cortisol concentration and mRNA expression of adrenal type 2 melanocortin receptor (MC2R) and StAR. These findings suggest that necroptosis is present and contributes to HPA axis activation induced by LPS. These findings provide a potential possibility for necroptosis as an intervention target for alleviating HPA axis activation and stress responses.

Characterization of CRH-Binding Protein (CRHBP) in Chickens: Molecular Cloning, Tissue Distribution and Investigation of Its Role as a Negative Feedback Regulator within the Hypothalamus-Pituitary-Adrenal Axis.

Corticotropin (ACTH) is a pituitary hormone playing important roles in stress response within the hypothalamus–pituitary–adrenal (HPA) axis. The biosynthesis and secretion of ACTH are controlled by multiple factors, including corticotropin-releasing hormone (CRH). As a key hypothalamus-derived regulator, CRH binds to corticotropin-releasing hormone receptor 1 (CRHR1) in the anterior pituitary gland to regulate ACTH synthesis and release. Thus, CRH-binding protein (CRHBP), which binds CRH with high affinity to inhibit CRH-induced ACTH secretion from pituitary cells, draws wide attention. In contrast to the extensive investigation of CRHBP in mammals and other lower vertebrates, the gene structure, tissue expression and physiological functions of CRHBP in birds remain largely unknown. In the present study, using chicken (c-) as our animal model, we examined the gene structure, tissue expression and functionality of CRHBP. Our results showed that: (1) cCRHBP cDNA encodes a 345 amino acid precursor, which shares high sequence identity with that of mammals, reptiles, frogs and fish; (2) cCRHBP is abundantly expressed in the brain (cerebrum and hypothalamus), pituitary and ovary; (3) cCRHBP inhibits the signaling of cCRHRs induced by cCRH, thus reducing the cCRH-induced ACTH secretion from cultured chick pituitary cells; (4) stress mediators (e.g., glucocorticoids) and stress significantly upregulate CRHBP mRNA expression in chickens, supporting its role as a negative feedback regulator in the HPA axis. The present study enriches our understanding of the conserved roles of CRHBP across vertebrates. In addition, chicken is an important poultry animal with multiple economic traits which are tightly controlled by the HPA axis. The characterization of the chicken CRHBP gene helps to reveal the molecular basis of the chicken HPA axis and is thus beneficial to the poultry industry.

Epigenetic Effects in HPA Axis Genes Associated with Cortical Thickness, ERP Components and SUD Outcome.

Association between familial loading for alcohol use disorders (AUD) and event-related potentials (ERPs) suggests a genetic basis for these oscillations though much less is known about epigenetic pathways influenced by environmental variation. Early life adversity (ELA) influences negative outcomes much later in life. The stress-activated neuropeptide corticotropin-releasing hormone (CRH) contributes to the deleterious effects of ELA on brain structure and function in animals. Accordingly, we hypothesized that ELA would be related to cortical thickness and electrophysiological characteristics through an epigenetic effect on CRH receptor type-1 (CRHR1) methylation. A total of 217 adolescent and young adult participants from either multiplex alcohol dependence or control families were scanned using magnetic resonance imaging (MRI) at 3T and cortical thickness was determined. Longitudinal follow-up across childhood, adolescence, and young adulthood provided developmental ERP data and measures of adversity. Blood samples for genetic and epigenetic analyses were obtained in childhood. Cortical thickness and visual ERP components were analyzed for their association and tested for familial risk group differences. Visual P300 amplitude at Pz and cortical thickness of the left lateral orbitofrontal region (LOFC), were significantly related to risk group status. LOFC cortical thickness showed a negative correlation with CRHR1 methylation status and with childhood total stress scores from the Life Stressors and Social Resources Inventory (LISRES). Stress scores were also significantly related to P300 amplitude recorded in childhood. The present results suggest that early life adversity reflected in greater total LISRES stress scores in childhood can impact the methylation of the CRHR1 gene with implications for brain development as seen in cortical thickness and electrophysiological signals emanating from particular brain regions.

CRHR1 mediates the transcriptional expression of pituitary hormones and their receptors under hypoxia.

Hypothalamus-pituitary-adrenal (HPA) axis plays critical roles in stress responses under challenging conditions such as hypoxia, via regulating gene expression and integrating activities of hypothalamus-pituitary-targets cells. However, the transcriptional regulatory mechanisms and signaling pathways of hypoxic stress in the pituitary remain to be defined. Here, we report that hypoxia induced dynamic changes in the transcription factors, hormones, and their receptors in the adult rat pituitary. Hypoxia-inducible factors (HIFs), oxidative phosphorylation, and cAMP signaling pathways were all differentially enriched in genes induced by hypoxic stress. In the pituitary gene network, hypoxia activated c-Fos and HIFs with specific pituitary transcription factors (Prop1), targeting the promoters of hormones and their receptors. HIF and its related signaling pathways can be a promising biomarker during acute or constant hypoxia. Hypoxia stimulated the transcription of marker genes for microglia, chemokines, and cytokine receptors of the inflammatory response. Corticotropin-releasing hormone receptor 1 (CRHR1) mediated the transcription of Pomc, Sstr2, and Hif2a, and regulated the function of HPA axis. Together with HIF, c-Fos initiated and modulated dynamic changes in the transcription of hormones and their receptors. The receptors were also implicated in the regulation of functions of target cells in the pituitary network under hypoxic stress. CRHR1 played an integrative role in the hypothalamus-pituitary-target axes. This study provides new evidence for CRHR1 involved changes of hormones, receptors, signaling molecules and pathways in the pituitary induced by hypoxia.

Effects of chronic stress on nectin1 levels in the mouse primary somatosensory cortex

Chronic exposure to stressful experiences impairs synaptic plasticity. Previous studies have shown that the spine densities of pyramidal neurons, the turnover of mushroom-type spines, and the excitatory–inhibitory balance in the primary somatosensory cortex (S1) are modulated by stress. Trans-synaptic cell adhesion molecules (CAMs) are implicated in stress-induced synaptic deficits. However, it remains unknown whether stress dysregulates CAMs in S1 and thereby impairs synaptic plasticity. In this study, we applied the early-life stress (ELS), chronic social defeat stress (CSDS), and chronic restraint stress paradigms and measured the mRNA levels of <i>nectin1</i> in S1 of wild-type and conditional forebrain corticotropin-releasing hormone receptor 1 type (CRHR1) conditional knockout mice. We found that ELS increased <i>nectin1</i> mRNA levels in S1 in adult but not adolescent mice. Moreover, CSDS increased the <i>nectin1</i> mRNA levels in S1 in adult mice via the CRH-CRHR1 system. Our findings suggest that S1 is vulnerable to repeated stress exposures at some life stages, and dysregulated <i>nectin1</i> expression may underlie stress-induced structural and functional abnormalities in S1.