Corticotropin releasing hormone activates CD14+ cells to induce endothelial barrier dysfunction

The peripheral corticotropin releasing factor family's role in vasculitis

Corticotropin releasing factor family peptides (CRF peptides) include 4 members, corticotropin releasing hormone (CRH), Urocortin (UCN1), UCN2 and UCN3. CRF peptides function via the two distinct receptors, CRF1 and CRF2. Among them, CRH/CRF1 has been recognized to influence immunity/inflammation peripherally. Both pro- and anti-inflammatory effects of CRH are reported. Likewise, UCNs, peripherally in cardiovascular system have been documented to have both potent protective and harmful effects, with UCN1 acting on both CRF1 & CRF2 and UCN2 & UCN3 on CRF2. We and others also observe protective and detrimental effects of CRF peptides/receptors on vasculature, with the latter of predominantly higher incidence, i.e., they play an important role in the development of vasculitis while in some cases they are found to counteract vascular inflammation. The pro-vasculitis effects of CRH & UCNs include increasing vascular endothelial permeability, interrupting endothelial adherens & tight junctions leading to hyperpermeability, stimulating immune/inflammatory cells to release inflammatory factors, and promoting angiogenesis by VEGF release while the anti-vasculitis effects may be just the opposite, depending on many factors such as different CRF receptor types, species and systemic conditions. Furthermore, CRF peptides' pro-vasculitis effects are found to be likely related to cPLA2 and S1P receptor signal pathway. This minireview will focus on summarizing the peripheral effects of CRF peptides on vasculature participating in the processes of vasculitis.

The Treatment of Tubal Inflammatory Infertility using Yinjia Tablets through EGFR/MEK/ERK Signaling Pathway based on Network Pharmacology

Background: Salpingitis obstructive infertility (SOI) refers to infertility caused by abnormal conditions such as tubal adhesion and blockage caused by acute and chronic salpingitis. SOI has a serious impact on women's physical and mental health and family harmony, and it is a clinical problem that needs to be solved urgently.

Objective: The purpose of the present study was to explore the potential pharmacological mechanisms of the Yinjia tablets (Yin Jia Pian, YJP) on tubal inflammation.

Methods: Networks of YJP-associated targets and tubal inflammation-related genes were constructed through the STRING database. Potential targets and pathway enrichment analysis related to the therapeutic efficacy of YJP were identified using Cytoscape and Database for Annotation, Visualization, and Integrated Discovery (metascape). E. coli was used to establish a rat model of tubal inflammation and to validate the predictions of network pharmacology and the therapeutic efficacy of YJP. H&E staining was used to observe the pathological changes in fallopian tubes. TEM observation of the ultrastructure of the fallopian tubes. ELISA was used to detect the changes of IL-6 and TNF-α in fallopian tubes. Immunohistochemistry was used to detect the expression of ESR1. The changes of Bcl-2, ERK1/2, p-ERK1/2, MEK, p-MEK, EGFR, and p-EGFR were detected by western blot.

Results: Through database analysis, it was found that YJP shared 105 identical targets with the disease. Network pharmacology analysis showed that IL-6, TNF, and EGFR belong to the top 5 core proteins associated with salpingitis, and EGFR/MEK/ERK may be the main pathway involved. The E. coli-induced disease rat model of fallopian tube tissue showed damage, mitochondrial disruption, and increased levels of the inflammatory factors IL-6 and TNF-α. Tubal inflammatory infertility rats have increased expression of Bcl-2, p-ERK1/2, p-MEK, and p-EGFR, and decreased expression of ESR1. In vivo, experiments showed that YJP improved damage of tissue, inhibited shedding of tubal cilia, and suppressed the inflammatory response of the body. Furthermore, YJP inhibited EGFR/MEK/ERK signaling, inhibited the apoptotic protein Bcl-2, and upregulated ESR1.

Conclusion: This study revealed that YJP Reducing tubal inflammation and promoting tissue repair may be associated with inhibition of the EGFR/MEK/ERK signaling pathway.

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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.

Restraint stress and elevation of corticotrophin-releasing hormone in female mice impair oocyte competence through activation of the tumour necrosis factor α (TNF-α) system

Studies have observed that restraint stress (RS) and the associated elevation in corticotrophin-releasing hormone (CRH) impair oocyte competence by triggering apoptosis of ovarian cells but the underlying mechanisms are largely unclear. Although one study demonstrated that RS and CRH elevation triggered apoptosis in ovarian cells and oocytes via activating Fas/FasL signalling, other studies suggested that RS might damage cells by activating other pathways as well as Fas signalling. The objective of this study was to test whether RS and CRH elevation impairs oocytes by activating tumour necrosis factor α (TNF-α) signalling. Our invivo experiments showed that RS applied during oocyte prematuration significantly increased expression of TNF-α and its receptor (TNFR1) while inducing apoptosis in both oocytes and mural granulosa cells (MGCs). Invitro treatment of MGCs with CRH significantly increased their apoptotic percentages and levels of TNF-α and TNFR1 expression. Invitro knockdown by interfering RNA, invivo knockout of the TNF-α gene or injection of TNF-α antagonist etanercept significantly relieved the adverse effects of RS and CRH on apoptosis of MGCs and/or the developmental potential and apoptosis of oocytes. The results suggest that RS and CRH elevation in females impair oocyte competence through activating TNF-α signalling and that a TNF-α antagonist might be adopted to ameliorate the adverse effects of psychological stress on oocytes.

Corticosterone induced apoptosis of mouse oviduct epithelial cells independent of the TNF-α system

It has been reported in recent studies that restraint stress on pregnant mice during the preimplantation stage elevated corticotrophin-releasing hormone (CRH) and glucocorticoid levels in the serum and oviducts; furthermore, CRH and corticosterone (CORT) impacted preimplantation embryos indirectly by triggering the apoptosis of oviductal epithelial cells (OECs) through activation of the Fas system. However, it remains unclear whether TNF-α signaling is involved in CRH- and/or glucocorticoid-induced apoptosis of OECs. In the present study, it was shown that culture with either CRH or CORT induced significant apoptosis of OECs. The culture of OECs with CRH augmented both FasL expression and TNF-α expression. However, culture with CORT increased FasL, but decreased TNF-α, expression significantly. Although knocking down/knocking out FasL expression in OECs significantly ameliorated the proapoptotic effects of both CRH and CORT, knocking down/knocking out TNF-α expression relieved only the proapoptotic effect of CRH but not that of CORT. Taken together, our results demonstrated that CRH-induced OEC apoptosis involved both Fas signaling and TNF-α signaling. Conversely, CORT-induced OEC apoptosis involved only the Fas, but not the TNF-α, signaling pathway. The data obtained are crucial for our understanding of the mechanisms by which various categories of stress imposed on pregnant females impair embryo development, as well as for the development of measures to protect the embryo from the adverse effects of stress.

Extra-adrenal glucocorticoid biosynthesis: implications for autoimmune and inflammatory disorders

Glucocorticoid synthesis is a complex, multistep process that starts with cholesterol being delivered to the inner membrane of mitochondria by StAR and StAR-related proteins. Here its side chain is cleaved by CYP11A1 producing pregnenolone. Pregnenolone is converted to cortisol by the enzymes 3-βHSD, CYP17A1, CYP21A2 and CYP11B1. Glucocorticoids play a critical role in the regulation of the immune system and exert their action through the glucocorticoid receptor (GR). Although corticosteroids are primarily produced in the adrenal gland, they can also be produced in a number of extra-adrenal tissue including the immune system, skin, brain, and intestine. Glucocorticoid production is regulated by ACTH, CRH, and cytokines such as IL-1, IL-6 and TNFα. The bioavailability of cortisol is also dependent on its interconversion to cortisone which is inactive, by 11βHSD1/2. Local and systemic glucocorticoid biosynthesis can be stimulated by ultraviolet B, explaining its immunosuppressive activity. In this review, we want to emphasize that dysregulation of extra-adrenal glucocorticoid production can play a key role in a variety of autoimmune diseases including multiple sclerosis (MS), lupus erythematosus (LE), rheumatoid arthritis (RA), and skin inflammatory disorders such as psoriasis and atopic dermatitis (AD). Further research on local glucocorticoid production and its bioavailability may open doors into new therapies for autoimmune diseases.

Chronic stress impacts the cardiovascular system: animal models and clinical outcomes

Psychological stresses are associated with cardiovascular diseases to the extent that cardiovascular diseases are among the most important group of psychosomatic diseases. The longstanding association between stress and cardiovascular disease exists despite a large ambiguity about the underlying mechanisms. An array of possibilities have been proposed including overactivity of the autonomic nervous system and humoral changes, which then converge on endothelial dysfunction that initiates unwanted cardiovascular consequences. We review some of the features of the two most important stress-activated systems, i.e., the humoral and nervous systems, and focus on alterations in endothelial function that could ensue as a result of these changes. Cardiac and hematologic consequences of stress are also addressed briefly. It is likely that activation of the inflammatory cascade in association with oxidative imbalance represents key pathophysiological components of stress-induced cardiovascular changes. We also review some of the commonly used animal models of stress and discuss the cardiovascular outcomes reported in these models of stress. The unique ability of animals for adaptation under stressful conditions lessens the extrapolation of laboratory findings to conditions of human stress. An animal model of unpredictable chronic stress, which applies various stress modules in a random fashion, might be a useful solution to this predicament. The use of stress markers as indicators of stress intensity is also discussed in various models of animal stress and in clinical studies.

Role of Corticotropin-releasing Factor in Gastrointestinal Permeability

The interface between the intestinal lumen and the mucosa is the location where the majority of ingested immunogenic particles face the scrutiny of the vast gastrointestinal immune system. Upon regular physiological conditions, the intestinal micro-flora and the epithelial barrier are well prepared to process daily a huge amount of food-derived antigens and non-immunogenic particles. Similarly, they are ready to prevent environmental toxins and microbial antigens to penetrate further and interact with the mucosal-associated immune system. These functions promote the development of proper immune responses and oral tolerance and prevent disease and inflammation. Brain-gut axis structures participate in the processing and execution of response signals to external and internal stimuli. The brain-gut axis integrates local and distant regulatory networks and super-systems that serve key housekeeping physiological functions including the balanced functioning of the intestinal barrier. Disturbance of the brain-gut axis may induce intestinal barrier dysfunction, increasing the risk of uncontrolled immunological reactions, which may indeed trigger transient mucosal inflammation and gut disease. There is a large body of evidence indicating that stress, through the brain-gut axis, may cause intestinal barrier dysfunction, mainly via the systemic and peripheral release of corticotropin-releasing factor. In this review, we describe the role of stress and corticotropin-releasing factor in the regulation of gastrointestinal permeability, and discuss the link to both health and pathological conditions.

Hypothalamic neurohormones and immune responses

The aim of this review is to provide a comprehensive examination of the current literature describing the neural-immune interactions, with emphasis on the most recent findings of the effects of neurohormones on immune system. Particularly, the role of hypothalamic hormones such as Thyrotropin-releasing hormone (TRH), Corticotropin-releasing hormone (CRH) and Gonadotropin-releasing hormone (GnRH). In the past few years, interest has been raised in extrapituitary actions of these neurohormones due to their receptors have been found in many non-pituitary tissues. Also, the receptors are present in immune cells, suggesting an autocrine or paracrine role within the immune system. In general, these neurohormones have been reported to exert immunomodulatory effects on cell proliferation, immune mediators release and cell function. The implications of these findings in understanding the network of hypothalamic neuropeptides and immune system are discussed.