Glucocorticoid Synthesis Research Articles

Pharmacological suppression of endogenous glucocorticoid synthesis attenuated blood pressure and heart rate response to acute restraint in Wistar rats.

Glucocorticoids (GCS) are known to modulate cardiovascular response during stress conditions. The present study was aimed to test the hypothesis that permissive and/or stimulating effect of GCs is essential for the maintenance of peripheral vascular resistance and for the adequate response of cardiovascular system to stressor exposure. The effects of acute pharmacological adrenalectomy (PhADX) on humoral and cardiovascular parameters were studied in adult Wistar rats under the basal conditions and during the acute restraint stress. Acute PhADX was performed by the administration of metyrapone and aminoglutethimide (100 mg/kg s.c. of each drug) resulting in a suppression of endogenous glucocorticoid synthesis. Blood pressure (BP), heart rate (HR) and core body temperature were measured using radiotelemetry. BP responses to administration of vasoactive agents were determined in pentobarbital-anesthetized animals. PhADX considerably attenuated stress-induced increase of BP, HR and core body temperature. PhADX did not abolish BP and HR lowering effects of ganglionic blocker pentolinium indicating preserved sympathetic function in PhADX rats. BP response to exogenous norepinephrine administration was attenuated in PhADX rats, suggesting reduced sensitivity of cardiovascular system. Suppression of corticosterone synthesis by PhADX increased basal plasma levels of ACTH, aldosterone and plasma renin activity in unstressed animals but there was no further increase of these hormones following stressor exposure. In conclusion, PhADX attenuated stress-induced rise of blood pressure, heart rate and core body temperature indicating an important permissive and/or stimulating role of glucocorticoids in the maintenance of the adequate response of cardiovascular system and thermoregulation to several stimuli including acute exposure to stressor.

A high-salt/high fat diet alters circadian locomotor activity and glucocorticoid synthesis in mice.

Salt is an essential nutrient; however, excessive salt intake is a prominent public health concern worldwide. Various physiological functions are associated with circadian rhythms, and disruption of circadian rhythms is a prominent risk factor for cardiovascular diseases, cancer, and immune disease. Certain nutrients are vital regulators of peripheral circadian clocks. However, the role of a high-fat and high-salt (HFS) diet in the regulation of circadian gene expression is unclear. This study aimed to investigate the effect of an HFS diet on rhythms of locomotor activity, caecum glucocorticoid secretion, and clock gene expression in mice. Mice administered an HFS diet displayed reduced locomotor activity under normal light/dark and constant dark conditions in comparison with those administered a normal diet. The diurnal rhythm of caecum glucocorticoid secretion and the expression levels of glucocorticoid-related genes and clock genes in the adrenal gland were disrupted with an HFS diet. These results suggest that an HFS diet alters locomotor activity, disrupts circadian rhythms of glucocorticoid secretion, and downregulates peripheral adrenal gland circadian clock genes.

Ozone increases plasma kynurenine-tryptophan ratio and impacts hippocampal serotonin receptor and neurotrophic factor expression: Role of stress hormones

Air pollution is associated with adverse impacts on the brain, including cognitive decline and increased incidence of dementia, depression and anxiety; however, underlying mechanisms remain unclear. We have shown that both ozone and particulate matter activate the hypothalamic-pituitary-adrenal (HPA) axis, increasing plasma glucocorticoids and altering mRNA profiles in multiple tissues including the brain. HPA axis dysregulation has been associated with central nervous system impacts, including key effects in the hippocampus; accordingly, we hypothesized that pollutant-dependent increases in glucocorticoid levels impact biological pathways relevant to brain health. Fischer-344 rats were treated with metyrapone (0 or 50 mg/kg), a glucocorticoid synthesis inhibitor, and exposed to ozone (0 or 0.8 ppm) for 4 h (n = 5/group) to investigate the role of glucocorticoids in ozone-dependent effects on tryptophan metabolism and expression of serotonin receptors and neurotrophic factors. Ozone increased plasma levels of the tryptophan metabolite kynurenine (~2-fold) and decreased tryptophan levels (~1.2 fold). Hippocampal expression of serotonin receptors exhibited differential regulation following exposure, and expression of key neurotrophic factors (brain-derived neurotrophic factor, vascular endothelial growth factor A, insulin-like growth factor-1, tyrosine kinase receptor B, b-cell lymphoma 2) was decreased. Some, but not all effects were abrogated by metyrapone treatment, suggesting both glucocorticoid-dependent and -independent regulation. Exposure to exogenous corticosterone (10 mg/kg) followed by clean air reproduced the ozone effects that were blocked with metyrapone, confirming the specificity of effects to glucocorticoids. These results indicate that ozone can modify pathways relevant to brain health and establish a role for the HPA axis in mediating these effects.

The Brain-Skin Connection and the Pathogenesis of Psoriasis: A Review with a Focus on the Serotonergic System.

Psoriasis is a common non-communicable chronic immune-mediated skin disease, affecting approximately 125 million people in the world. Its pathogenesis results from a combination of genetic and environmental factors. The pathogenesis of psoriasis seems to be driven by the interaction between innate immune cells, adaptive immune cells and keratinocytes, in a process mediated by cytokines (including interleukins (IL)-6, IL-17 and IL-22, interferon and tumor necrosis factor) and other signaling molecules. This leads to an inflammatory process with increased proliferation of epidermal cells, neo-angiogenesis and infiltration of dendritic cells in the skin. Dysfunctional de novo glucocorticoid synthesis in psoriatic keratinocytes and the skin microbiome have also been suggested as mediators in the pathogenesis of this disease. To understand psoriasis, it is essential to comprehend the processes underlying the skin immunity and neuroendocrinology. This review paper focuses on the skin as a neuroendocrine organ and summarizes what is known about the skin immune system, the brain–skin connection and the role played by the serotonergic system in skin. Subsequently, the alterations of neuroimmune processes and of the serotonergic system in psoriatic skin are discussed, as well as, briefly, the genetic basis of psoriasis.

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.

Bed nuclei of the stria terminalis modulate memory consolidation via glucocorticoid-dependent and -independent circuits

There is extensive evidence that glucocorticoid hormones enhance memory consolidation, helping to ensure that emotionally significant events are well remembered. Prior findings suggest that the anteroventral region of bed nuclei of the stria terminalis (avBST) regulates glucocorticoid release, suggesting the potential for avBST activity to influence memory consolidation following an emotionally arousing learning event. To investigate this issue, male Sprague-Dawley rats underwent inhibitory avoidance training and repeated measurement of stress hormones, immediately followed by optogenetic manipulations of either the avBST or its projections to downstream regions, and 48 h later were tested for retention. The results indicate that avBST inhibition augmented posttraining pituitary-adrenal output and enhanced the memory for inhibitory avoidance training. Pretreatment with a glucocorticoid synthesis inhibitor blocked the memory enhancement as well as the potentiated corticosterone response, indicating the dependence of the memory enhancement on glucocorticoid release during the immediate posttraining period. In contrast, posttraining avBST stimulation decreased retention yet had no effect on stress hormonal output. Subsequent experiments revealed that inhibition of avBST input to the paraventricular hypothalamus enhanced stress hormonal output and subsequent retention, whereas stimulation did not affect either. Conversely, stimulation-but not inhibition-of avBST input to the ventrolateral periaqueductal gray impaired consolidation, whereas neither manipulation affected glucocorticoid secretion. These findings indicate that divergent pathways from the avBST are responsible for the mnemonic effects of avBST inhibition versus stimulation and do so via glucocorticoid-dependent and -independent mechanisms, respectively.

VLDL/LDL serves as the primary source of cholesterol in the adrenal glucocorticoid response to food deprivation

The contribution of individual lipoprotein species to the generation of the adrenal cholesterol pool used for the synthesis of anti-inflammatory glucocorticoid species remains unknown. Here we examined the impact of specific lowering of very low-density lipoprotein (VLDL) and low-density (LDL) levels on adrenal cholesterol and glucocorticoid homeostasis. Hereto, lethally-irradiated hypercholesterolemic apolipoprotein E (APOE) knockout mice received APOE-containing bone marrow from wild-type mice (n = 6) or APOE knockout control bone marrow (n = 10) and were subsequently fed a regular chow diet. Transplantation with wild-type bone marrow was associated with a 10-fold decrease in VLDL/LDL-cholesterol levels. No changes were observed in adrenal weights, adrenal cholesterol content, or basal plasma corticosterone levels. However, food deprivation-induced corticosterone secretion was 64% lower (P < 0.05) in wild-type bone marrow recipients as compared to APOE knockout bone marrow recipients, in the context of similar plasma adrenocorticotropic hormone (ACTH) levels. A parallel 19–29% decrease in adrenal relative mRNA expression levels of ACTH-responsive genes SR-BI (P < 0.01), STAR (P < 0.05), and CYP11A1 (P < 0.05) was detected. In support of relative glucocorticoid insufficiency, blood lymphocyte and eosinophil concentrations were respectively 2.4-fold (P < 0.01) and 8-fold (P < 0.001) higher in wild-type bone marrow recipients under food deprivation stress conditions.In conclusion, we have shown that a selective lowering of VLDL/LDL levels in APOE knockout mice through a transplantation with APOE-containing wild-type bone marrow is associated with a decreased maximal adrenal glucocorticoid output. Our studies provide experimental support for the hypothesis that, in vivo, VLDL/LDL serves as the primary source of cholesterol used for glucocorticoid synthesis during food deprivation stress.

Pharmacological LRH-1/Nr5a2 inhibition limits pro-inflammatory cytokine production in macrophages and associated experimental hepatitis

Liver receptor homolog-1 (LRH-1, Nr5a2) is an orphan nuclear receptor mainly expressed in tissues of endodermal origin, where its physiological role has been extensively studied. LRH-1 has been implicated in liver cell differentiation and proliferation, as well as glucose, lipid, and bile acid metabolism. In addition, increasing evidence highlights its role in immunoregulatory processes via glucocorticoid synthesis in the intestinal epithelium. Although the direct function of LRH-1 in immune cells is fairly elucidated, a role of LRH-1 in the regulation of macrophage differentiation has been recently reported. In this study, we aimed to investigate the role of LRH-1 in the regulation of pro-inflammatory cytokine production in macrophages. Our data demonstrate that pharmacological inhibition, along with LRH-1 knockdown, significantly reduced the lipopolysaccharide (LPS)-induced production of pro-inflammatory cytokines in the macrophage line RAW 264.7 cells, as well as in primary murine macrophages. This inhibitory effect was found to be independent of defects of LRH-1-regulated cell proliferation or toxic effects of the LRH-1 inhibitors. In contrast, LRH-1 inhibition reduced the mitochondrial ATP production and metabolism of macrophages through downregulation of the LRH-1 targets glucokinase and glutminase-2, and thus impairing the LPS-induced macrophage activation. Interestingly, in vivo pharmacological inhibition of LRH-1 also resulted in reduced tumor necrosis factor (TNF) production and associated decreased liver damage in a macrophage- and TNF-dependent mouse model of hepatitis. Noteworthy, despite hepatocytes expressing high levels of LRH-1, pharmacological inhibition of LRH-1 per se did not cause any obvious liver damage. Therefore, this study proposes LRH-1 as an emerging therapeutic target in the treatment of inflammatory disorders, especially where macrophages and cytokines critically decide the extent of inflammation.

Steroids, Pregnancy and Fetal Development.

Maternal glucocorticoids critically rise during pregnancy reaching up to a 20-fold increase of mid-pregnancy concentrations. Concurrently, another steroid hormone, progesterone, increases. Progesterone, which shows structural similarities to glucocorticoids, can bind the intracellular glucocorticoid receptor, although with lower affinity. Progesterone is essential for the establishment and continuation of pregnancy and it is generally acknowledged to promote maternal immune tolerance to fetal alloantigens through a wealth of immunomodulatory mechanisms. Despite the potent immunomodulatory capacity of glucocorticoids, little is known about their role during pregnancy. Here we aim to compare general aspects of glucocorticoids and progesterone during pregnancy, including shared common steroidogenic pathways, plasma transporters, regulatory pathways, expression of receptors, and mechanisms of action in immune cells. It was recently acknowledged that progesterone receptors are not ubiquitously expressed on immune cells and that pivotal features of progesterone induced- maternal immune adaptations to pregnancy are mediated via the glucocorticoid receptor, including e.g., T regulatory cells expansion. We hypothesize that a tight equilibrium between progesterone and glucocorticoids is critically required and recapitulate evidence supporting that their disequilibrium underlie pregnancy complications. Such a disequilibrium can occur, e.g., after maternal stress perception, which triggers the release of glucocorticoids and impair progesterone secretion, resulting in intrauterine inflammation. These endocrine misbalance might be interconnected, as increase in glucocorticoid synthesis, e.g., upon stress, may occur in detriment of progesterone steroidogenesis, by depleting the common precursor pregnenolone. Abundant literature supports that progesterone deficiency underlies pregnancy complications in which immune tolerance is challenged. In these settings, it is largely yet undefined if and how glucocorticoids are affected. However, although progesterone immunomodulation during pregnancy appear to be chiefly mediated glucocorticoid receptors, excess glucocorticoids cannot compensate by progesterone deficiency, indicating that additional und still undercover mechanisms are at play.

Evidence in Favor of an Alternative Glucocorticoid Synthesis Pathway During Acute Experimental Chagas Disease.

It is well-established that infectious stress activates the hypothalamus–pituitary–adrenal axis leading to the production of pituitary adrenocorticotropin (ACTH) and adrenal glucocorticoids (GCs). Usually, GC synthesis is mediated by protein kinase A (PKA) signaling pathway triggered by ACTH. We previously demonstrated that acute murine Chagas disease courses with a marked increase of GC, with some data suggesting that GC synthesis may be ACTH-dissociated in the late phase of this parasitic infection. Alternative pathways of GC synthesis have been reported in sepsis or mental diseases, in which interleukin (IL)-1β, prostaglandin E2 (PGE2), and/or cAMP-activated guanine nucleotide exchange factor 2 (EPAC2) are likely to play a role in this regard. Accordingly, we have searched for the existence of an ACTH-independent pathway in an experimental model of a major parasitic disease like Chagas disease, in addition to characterizing potential alternative pathways of GC synthesis. To this end, C57BL/6 male mice were infected with T. cruzi (Tc), and evaluated throughout the acute phase for several parameters, including the kinetic of GC and ACTH release, the adrenal level of MC2R (ACTH receptor) expression, the p-PKA/PKA ratio as ACTH-dependent mechanism of signal transduction, as well as adrenal expression of IL-1β and its receptor, EPAC2 and PGE2 synthase. Our results reveal the existence of two phases involved in GC synthesis during Tc infection in mice, an initial one dealing with the well-known ACTH-dependent pathway, followed by a further ACTH-hyporesponsive phase. Furthermore, inflamed adrenal microenvironment may tune the production of intracellular mediators that also operate upon GC synthesis, like PGE2 synthase and EPAC2, as emerging driving forces for GC production in the advanced course of Tc infection. In essence, GC production seems to be associated with a biphasic action of PGE2, suggesting that the effect of PGE2/cAMP in the ACTH-independent second phase may be mediated by EPAC2.

Участие гормонов гипоталамо-гипофизарно-адренокортикальной системы крыс в гастропротекции при сенситизации и десенситизации капсаицин-чувствительных афферентных нейронов

The aim of this work was to study: a) the contribution of glucocorticoids to gastroprotection induced by sensitization of capsaicin-sensitive afferent neurons (CSN), b) gastroprotective effect of corticotropin-releasing factor (CRF) in rats with desensitization of CSN and possible corticosterone participation in this effect. The study was performed in male Sprague Dawley rats weighing 260-300 g. The immobilization at 10° C (3 h) or indomethacin (35 mg/kg) were used as ulcerogenic stimuli. Sensitization of CSN was induced by administration of capsaicin at the doses of 1 and 10 mg/kg, 1h before the onset of ulcerogenic stimulus. Desensitization was performed by administration of capsaicin in a total dose of 100 mg/kg (20+30+50) in 3 subsequent days, 2 weeks before the start of the experiment. CRF was injected at the dose of 2.5 mg/kg, i. p., 30 minutes before indomethacin in rats with CSN desensitization. To estimate the involvement of corticosterone in the gastroprotective effects, metyrapone (inhibitor of glucocorticoid synthesis) at the dose of 30 mg/kg was used. Capsaicin, administered at doses of 1 and 10 mg/kg, caused a gastroprotective effect in both ulcerogenic models. The metyrapone administration 30 minutes before capsaicin eliminated its gastroprotective effect for the 1 mg/kg dose, but not 10 mg/kg dose. The CRF administration caused a gastroprotective effect in both control rats, and rats with CSN desensitization. The results obtained in experiments with metyrapone indicate that CRF gastroprotective effect observed in rats with desensitization of CSN are at least partially mediated by corticosterone.

Substrates and Clearance Products of Fetal Adrenal Glucocorticoid Synthesis in Full-Term Human Umbilical Circulation.

In full-term elective caesarian sections, fetal flow of adrenal substrate steroids to products differs by sex, with males (M) in molar equilibrium whereas females (F) add net molarity and synthesize more cortisol. Using the same sampling design, paired, full-term, arterial, and venous umbilical cord samples and intrapartum chart records were obtained at the time of vaginal delivery (N = 167, 85 male) or emergency C-section (N = 38, 22 male). Eight steroids were quantified by liquid chromatography coupled to tandem mass spectrometry (adrenal glucocorticoids [cortisol, corticosterone], sequential cortisol precursor steroids [17-hydroxyprogesterone, 11-deoxycortisol], cortisol and corticosterone metabolites [cortisone and 11-dehydrocorticosterone], and gonadal steroids [androstenedione, testosterone]). Fetal sex was not significant in any analytic models. Going through both phase 1 and phase 2 labor increased fetal adrenal steroidogenesis and decreased male testosterone relative to emergency C-sections that do not reach stage 2 of labor (ie, head compressions) and elective C-sections with no labor. Sum adrenal steroid molarity arriving in venous serum was almost double the equivalent metric for deliveries without labor. No effects of operative vaginal delivery were noted. Maternal regional anesthetic suppressed venous concentrations, and fetal synthesis replaced that steroid. Approximate molar equivalence between substrate pool depletion and net glucocorticoid synthesis was seen. Paired venous and arterial umbilical cord serum has the potential to identify sex differences that underlie antenatal programming of hypothalamic-pituitary-adrenal axis function in later life. However, stage 2 labor before the collection of serum, and regional anesthetic for the mother, mask those sex differences.

Psychosocial research in the diabetic foot: Are we making progress?

This review summarizes recent advances regarding the role of psychological factors in people with a diabetic foot ulcer (DFU). It describes the detrimental effects of diabeticfoot complications and in particular, Charcot Neuroarthropathy (CN), on health status and quality of life (QoL) and emphasizes the importance of utilizing DFU-specific assessment tools. Diabetic neuropathy (DN)-related postural instability is key in generating depression in high DFU risk patients and in predicting offloading non-adherence those with active DFUs. Patients' views of their own DFU risk are largely inconsistent with biomedical models, resulting in a lack of preventive foot self-care. Furthermore, DFUs are a source of specific emotional responses, with fear of amputation predominant. While fear of amputation is associated with better preventive foot self-care, it appears to be linked to DFU non-healing, though mechanisms are yet to be elucidated. Until now, systemically released stress hormones were recognized as the only biological mechanism through which psychological stress influences healing. Recently, the skin has been found to be an extra-adrenal site for glucocorticoid synthesis with local, tissue-specific cortisol implicated in DFU non-healing. These observations could potentially lead to future targets for therapeutic and psychological interventions.

Interactions Between Gut Microbiota and Acute Restraint Stress in Peripheral Structures of the Hypothalamic-Pituitary-Adrenal Axis and the Intestine of Male Mice.

The gut microbiota play an important role in shaping brain functions and behavior, including the activity of the hypothalamus-pituitary-adrenocortical (HPA) axis. However, little is known about the effect of the microbiota on the distinct structures (hypothalamus, pituitary, and adrenals) of the HPA axis. In the present study, we analyzed the influence of the microbiota on acute restraint stress (ARS) response in the pituitary, adrenal gland, and intestine, an organ of extra-adrenal glucocorticoid synthesis. Using specific pathogen-free (SPF) and germ-free (GF) male BALB/c mice, we showed that the plasma corticosterone response to ARS was higher in GF than in SPF mice. In the pituitary, stress downregulated the expression of the gene encoding CRH receptor type 1 (Crhr1), upregulated the expression of the Fkbp5 gene regulating glucocorticoid receptor sensitivity and did not affect the expression of the proopiomelanocortin (Pomc) and glucocorticoid receptor (Gr) genes. In contrast, the microbiota downregulated the expression of pituitary Pomc and Crhr1 but had no effect on Fkbp5 and Gr. In the adrenals, the steroidogenic pathway was strongly stimulated by ARS at the level of the steroidogenic transcriptional regulator Sf-1, cholesterol transporter Star and Cyp11a1, the first enzyme of steroidogenic pathway. In contrast, the effect of the microbiota was significantly detected at the level of genes encoding steroidogenic enzymes but not at the level of Sf-1 and Star. Unlike adrenal Sf-1, the expression of the gene Lrh-1, which encodes the crucial transcriptional regulator of intestinal steroidogenesis, was modulated by the microbiota and ARS and this effect differed between the ileum and colon. The findings demonstrate that gut microbiota have an impact on the response of the pituitary, adrenals and intestine to ARS and that the interaction between stress and the microbiota during activation of glucocorticoid steroidogenesis differs between organs. The results suggest that downregulated expression of pituitary Pomc and Crhr1 in SPF animals might be an important factor in the exaggerated HPA response of GF mice to stress.

The Gut Microbiome Regulates Psychological Stress-Induced Inflammation in Sickle Cell Disease

Psychological stress (PS) is reported to precipitate vaso-occlusive episides (VOE) in sickle cell disease (SCD), but the mechanisms by which it does, are largely unknown. We subjected humanized (Berkeley) SCD mice to restraint stress and analyzed VOE using intravital microscopy. We found that stress exacerbated VOE as shown by reduced venular blood flow rates (control: 494 ± 30 × 103 pL/s; stress: 380 ± 20 × 103 pL/s; n = 25 - 43; p = 0.009) and reduced survival time (median survival time in control and stress groups: 394 min and 175 min, respectively; p = 0.02, Log-rank test). As previous studies show that adherent polymorphonuclear neutrophils (PMNs), especially aged PMNs marked by low CD62L and high CXCR4 expression, contribute to VOEs, we evaluated the behavior of leukocytes in live mice and observed a robust PMN response manifested by significantly increased adhesion and interactions with sickle RBC in stressed SCD animals. Flow cytometry analysis revealed a striking increase in aged PMNs in stressed SCD mice (control: 0.7 ± 0.1 × 106/ml; stress: 2.9 ± 0.3 × 106/ml; n = 3 - 4; p = 0.001), suggesting that the aged PMN expansion induced by stress may lead to the exacerbation of VOE in stressed SCD mice. Since aged PMN numbers are regulated by microbiota under steady state, we investigated whether response to PS also required the presence of the microbiota. Depletion of microbiota with broad-spectrum antibiotics (ABX) in SCD mice significantly prevented stress-induced aged PMN expansion (control: 4.8 ± 1.2 × 106/ml; ABX: 1.2 ± 0.3× 106/ml; n = 4 - 5; p = 0.0006), which was further confirmed using C57BL/6 germ-free (GF) mice (control: 1.1 ± 0.3 × 106/ml; GF: 0.2 ± 0.1 × 106/ml; n = 4; p = 0.003). Interestingly, analysis of inflammatory cytokines revealed a microbiota-dependent augmentation of IL-17A in the stressed mice. To investigate the role of IL-17A in the stress response, we neutralized IL-17A using an antibody (Ab) in C57BL/6 mice and found that IL-17A inhibition significantly dampened the aged PMN expansion induced by stress (isotype control Ab: 0.6 ± 0.1 × 106/ml; anti-IL-17A: 0.1 ± 0.0 × 106/ml; n = 4 - 5; p = 0.0004), which was also confirmed using IL-17A-/- mice. Further analyses revealed that Th17 lymphocytes were the major IL-17A-producing cells contributing to the stress response. In addition, depletion of microbiota with ABX or neutralization of IL-17A significantly alleviated stress-exacerbated VOE as measured by reduced PMN activation, improved blood flow rate and prolonged SCD mouse survival. As segmented filamentous bacteria (SFB) commensals were previously found to induce a Th17 response, we next tested the hypothesis that SFB was the driving bacteria in the stress response. Indeed, we found that PS-induced aged PMN expansion was greater in SFB+ mice (from Taconic) than in SFB- mice (from Jackson lab) (Taconic: 0.64 ± 0.11× 106/ml; Jax: 0.13 ± 0.02 × 106/ml; n = 4 - 5; p = 0.005). Depletion of SFB using vancomycin, a drug that eliminates Gram+ bacteria (including SFB), significantly reduced stress-induced aged PMN expansion. Furthermore, colonization of GF mice with SFB augmented aged PMN expansion after stress compared to stress control GF mice (control GF: 0.08 ± 0.02 × 106/ml; GF + SFB: 0.34 ± 0.10× 106/ml; n = 4 - 5; p = 0.04), suggesting that SFB was the key bacteria promoting aged PMN expansion during stress. The stress mechanisms involved the hypothalamic-pituitary-adrenal (HPA) axis since the blockade of glucocorticoid (GC) production using metyrapone or following adrenalectomy significantly prevented aged PMN expansion in stressed mice (PBS: 0.5 ± 0.1 × 106/ml; metyrapone: 0.1 ± 0.1× 106/ml; n = 5; p = 0.02. sham: 1.2 ± 0.2 × 106/ml; adrenalectomy: 0.4 ± 0.2 × 106/ml; n = 4 - 5; p = 0.01). Moreover, PS and dexamethasone greatly increased the gut permeability. Blockade of GC synthesis using metyrapone significantly alleviated stress-induced exacerbation of VOE manifested by reduced inflammation, improved the blood flow rate and prolonged SCD mice survival (median survival time in control and metyrapone groups: 155 min and 200 min, respectively; p = 0.02, Log-rank test). Overall, our results suggest that stress activation of the HPA axis increases the intestinal permeability, thereby promoting exposure to commensals that stimulate Th17 cells to produce IL-17A, which enables the expansion of aged polymorphonuclear neutrophils driving vaso-occlusion in SCD. Disclosures Frenette: Albert Einstein College of Medicine, Inc: Patents &amp; Royalties; Ironwood Pharmaceuticals: Research Funding; Cygnal Therapeutics: Equity Ownership; Pfizer: Consultancy.

Long-term triphenyltin exposure disrupts adrenal function in adult male rats.

Triphenyltin is an organotin, which is widely used as a fungicide in agriculture. Here, we reported the effects of triphenyltin on adrenal function in adult male rats. Adult male Sprague Dawley rats were daily gavaged with triphenyltin (0, 0.5, 1, and 2 mg/kg body weight) from postnatal day 56-86. Triphenyltin significantly decreased serum corticosterone levels at 1 and 2 mg/kg without affecting serum levels of aldosterone and adrenocorticotropic hormone. Triphenyltin increased thickness of zona glomerulosa without affecting that of zona fasciculata. Triphenyltin did not affect cell number in zona fasciculata and zona glomerulosa. Triphenyltin down-regulated the expression of Scarb1, Star, Cyp11a1, Hsd3b1, Cyp21, Cyp11b1, and Hsd11b1 at 1 and/or 2 mg/kg while it up-regulated the expression of At1, Nr4a2, and Hsd11b2 at 2 mg/kg. Triphenyltin activated the phosphorylation of AMPKα while suppressed the phosphorylation of AKT1 and SIRT1/PGC-1α in rat adrenals invivo and H295R cells invitro. Invitro, triphenyltin also induced ROS production in H295R cells at 100 nM, a concentration at which no apoptosis was induced. In conclusion, triphenyltin disrupts glucocorticoid synthesis in rat adrenal cortex via several mechanisms: 1) lowering AKT1 phosphorylation and SIRT1/PGC-1α levels; 2) activating AMPKα; and 3) possibly inducing ROS production.

321 The role of abnormal cutaneous steroidogenesis in the pathogenesis of rosacea

Rosacea is a chronic inflammatory disorder usually affecting the central face. Chronic use of topical steroids on the face causes lesions similar to rosacea. Synthesis and function of glucocorticoid (GC) have been established in healthy skin and various cutaneous diseases but not in rosacea. In most skin disorders, increased inflammation is usually coupled with a decline in the production of cutaneous GC. We investigated the de novo GC synthesis in the skin and GC receptor expression in the lesional and the nonlesional skin of patients with erythematotelangiectatic rosacea (ETR). Both lesional and non-lesional facial skin samples from the same individuals were provided by 12 ETR patients (mean age, 40.1 years; range, 30 to 55 years). The key steroidogenic enzymes, CYP11A1, 3βHSD2 and CYP21A2, were significantly increased in the lesional skin at the gene and protein levels. CYP17A1 and steroidogenic acute regulatory protein (StAR) tended to be higher in the lesional skin. GC receptor was also significantly increased in the lesional skin. Progesterone was increased significantly in the lesional skin using liquid chromatography-mass spectrometry Simultaneously, p65/p50 subunits of nuclear factor kappa-light-chain enhancer of activated B cells (NFκB) and matrix metalloproteinases (MMP) gene expressions were significantly increased in the lesional skin. Furthermore, p65 and p105 protein levels were significantly increased. These results demonstrate that crosstalk between GC receptor and NFκB may be hampered in the lesional skin of ETR and may contribute to rosacea pathogenesis. We demonstrate that ETR is an inherently inflammatory disorder mediated by NFκB and that GC synthesis and GC receptor expression is increased in the lesional skin of ETR unlike in other cutaneous inflammatory diseases.

Identification of small molecule inhibitors of glucocorticoid synthesis

Identification of small molecule inhibitors of glucocorticoid synthesis

A General Introduction to Glucocorticoid Biology.

Glucocorticoids (GCs) are steroid hormones widely used for the treatment of inflammation, autoimmune diseases, and cancer. To exert their broad physiological and therapeutic effects, GCs bind to the GC receptor (GR) which belongs to the nuclear receptor superfamily of transcription factors. Despite their success, GCs are hindered by the occurrence of side effects and glucocorticoid resistance (GCR). Increased knowledge on GC and GR biology together with a better understanding of the molecular mechanisms underlying the GC side effects and GCR are necessary for improved GC therapy development. We here provide a general overview on the current insights in GC biology with a focus on GC synthesis, regulation and physiology, role in inflammation inhibition, and on GR function and plasticity. Furthermore, novel and selective therapeutic strategies are proposed based on recently recognized distinct molecular mechanisms of the GR. We will explain the SEDIGRAM concept, which was launched based on our research results.

Extra-Adrenal Glucocorticoid Synthesis in the Intestinal Mucosa: Between Immune Homeostasis and Immune Escape.

Glucocorticoids (GCs) are steroid hormones predominantly produced in the adrenal glands in response to physiological cues and stress. Adrenal GCs mediate potent anti-inflammatory and immunosuppressive functions. Accumulating evidence in the past two decades has demonstrated other extra-adrenal organs and tissues capable of synthesizing GCs. This review discusses the role and regulation of GC synthesis in the intestinal epithelium in the regulation of normal immune homeostasis, inflammatory diseases of the intestinal mucosa, and the development of intestinal tumors.