Endocrinology

Pregnancy leads to many adaptations in the maternal body, most of which are reversible. However, reproductive experience can also result in permanent effects. Here, we investigated how pregnancy influences the somatotrophic system and the lasting effects of reproductive experience on the maternal organism. Reproductive experience induced a pronounced increase in lean body mass and longitudinal growth in both wild-type and growth hormone (GH)-deficient mice compared with age-matched virgins. Body growth was primarily observed during the first pregnancy, whereas a second gestation was mostly associated with increased adiposity. Data from a cohort of women with isolated GH deficiency (IGHD) caused by a loss-of-function mutation in the GHRHR gene revealed that nulliparous women were 7 cm shorter than those with one or more pregnancies. Increased GH secretion was observed in pregnant wild-type mice but not in pregnant GHRHR-deficient mice. Pregnancy-induced body growth is preserved despite disruption of GH-, ghrelin-, and estrogen-related signaling pathways. In conclusion, reproductive experience induces permanent changes in the maternal organism, promoting body growth in models that allow this response. Pregnancy-induced body growth appears to be independent of GH action. These findings underscore the need for further studies to investigate the long-lasting consequences of reproductive experience in females.

ObjectiveThe aryl hydrocarbon receptor (AhR) pathway primarily mediates pollutant responses by activating xenobiotic metabolism enzymes like cytochrome P450 1A1 and 1A2 (CYP1A). Although AhR has also been implicated in systemic metabolic dysfunction and is inducible in pancreatic islets, its role in islet physiology remains unclear. MethodsWe analyzed a publicly available bulk human islet transcriptomic dataset to identify pathways associated with CYP1A1 expression. We also assessed islet responses to the pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and glucolipotoxicity (GLT) in vitro using two mouse models: a global Cyp1a1/1a2 double knockout (CypKO) model, which disrupts canonical AhR-CYP1A signaling in whole islets, and a {beta}-cell-specific Ahr knockout ({beta}AhrKO) model, which abolishes AhR signaling selectively in {beta}-cells. We then examined the role of {beta}-cell Ahr in early adaptation to high-fat diet (HFD) feeding in vivo. ResultsXenobiotic and nutrient metabolism pathways were enriched in donors with high CYP1A1 expression. Global Cyp1a1/1a2 deletion increased susceptibility of female mouse islets to TCDD-induced impairments in insulin secretion but had minimal effects on GLT responses in either sex. In contrast, {beta}-cell Ahr deletion did not affect islet responses to TCDD, but exacerbated GLT-induced islet dysfunction in male islets and increased baseline insulin secretion in both vehicle- and GLT-exposed female islets in vitro. Lastly, {beta}-cell Ahr deletion prevented adaptive HFD-induced hyperinsulinemia in both sexes in vivo. ConclusionIslet AhR signaling shapes responses to chemical and nutrient stressors in a context- and sex-dependent manner. While the canonical AhR-CYP1A axis supports female islet resilience to TCDD, {beta}-cell AhR signaling more broadly regulates nutrient stress responses in both sexes.

The endometrium is the innermost compartment of the uterus and undergoes cyclical remodeling throughout the human menstrual cycle and the rodent estrous cycle. The endometrium must thicken appropriately for embryonic implantation to occur; thus, it is crucial to understand the molecular mechanisms downstream of steroid hormone action that regulate endometrial thickness. Hedgehog (Hh) signaling is required for endometrial remodeling in both mice and humans, but the role of downstream Hh transcriptional effectors in endometrial remodeling is unknown. Here, we discover a role for the Hh transcriptional repressor, Gli3, in endometrial homeostasis: conditional knockout of Gli3 resulted in a constitutively thick endometrium throughout the estrous cycle. In our model, a constitutively thick endometrium could support pregnancy. Bulk RNA-sequencing data revealed that loss of Gli3 also resulted in dysregulated stromal-epithelial crosstalk, while immunofluorescent staining showed larger uterine glands and increased gland proliferation. These data deepen our understanding of molecular mechanisms controlling endometrial thickness, offering novel pathways to investigate endometrial factors in infertility.

To facilitate the investigation of signaling by the luteinizing hormone receptor (LHR), we created a mouse line called Lhr-COIN. This line allows for the conditional replacement of the Lhr coding sequence with enhanced green fluorescent protein (eGFP), resulting in both a conditional knockout line and a reporter line. By breeding these mice with mice expressing Cre recombinase, we generated mice in which either one or both Lhr alleles were replaced with eGFP. Notably, mice in which one Lhr allele in the granulosa cells was replaced with eGFP exhibited normal LH responsiveness. This enabled live imaging of LH-induced migration of LH-receptor-expressing granulosa cells within preovulatory ovarian follicles. The Lhr-COIN mouse line holds significant potential for future research on LHR function and localization in the ovary and other tissues.

Ovarian disorders, including anovulation, primary ovarian insufficiency (POI), and polyendocrine metabolic ovarian syndrome (PMOS), affect millions of reproductive-age women worldwide; however, mechanistic studies of ovarian biology and pathophysiology remain challenging because current experimental approaches often lack selectivity, tunability, or physiological relevance. Genetically modified animal models are labor-intensive and irreversible; small molecules frequently exhibit off-target effects; and conventional antibodies have limited tissue penetration and restricted temporal control. Designed ankyrin repeat proteins (DARPins) represent a highly modular protein engineering platform with advantages in specificity, size, stability, and extracellular targeting, but their utility in reproductive biology remains largely unexplored. Here, we used epidermal growth factor receptor (EGFR)-targeting DARPins as a proof-of-concept platform to interrogate ovarian signaling during ovulation. Screening of engineered anti-EGFR DARPins identified SX-006, a bispecific tetravalent construct with robust cross-species EGFR binding and potent biological activity. Using an ex vivo murine ovulation system, SX-006 inhibited follicle rupture in a dose-dependent manner with IC50 of 1.21 M without overt cytotoxicity. Lower concentrations of SX-006 preferentially perturbed follicle rupture while largely preserving oocyte meiotic maturation and luteinization, suggesting differential sensitivity of ovulatory processes to extracellular EGFR blockade. Comparative transcriptomic analyses further revealed that extracellular EGFR blockade and small molecule-based intracellular EGFR kinase inhibition produce overlapping but also distinct transcriptional responses, supporting biologically distinct modes of ovulatory signaling pathway perturbation. Together, these findings establish DARPins as a selective, tunable, and physiologically relevant platform for studying ovarian signaling and provide proof-of-concept for extracellular receptor targeting in ovarian biology, infertility research, and non-hormonal contraceptive development. Summary sentenceAn engineered EGFR-targeting DARPin selectively inhibits ovulation through extracellular receptor blockade and establishes a versatile platform for investigating ovarian signaling and reproductive disorders.

Leydig cells (LCs) are essential for male reproductive function due to their role in testosterone synthesis, a process critically dependent on mitochondrial cholesterol transport mediated by the Steroidogenic Acute Regulatory protein (StAR). Despite their importance, LCs are highly sensitive to metabolic and exogenous stressors. Ferroptosis, an iron-dependent form of regulated cell death driven by lipid peroxidation, has emerged as a key link between cellular metabolism and cell fate; however, its role in LCs and steroidogenesis remains poorly understood. In this study, we investigated the induction of ferroptosis in LCs and its impact on their steroidogenic capacity. We evaluated cellular responses to canonical ferroptosis inducers (Erastin and RSL3) alongside the transcriptional regulation of key genes. Our results demonstrate that LCs are vulnerable to ferroptotic stress, which significantly downregulates Star expression. Notably, we uncovered a novel endocrine-metabolic crosstalk: hormonal stimulation via hCG effectively rescues LCs from Erastin-induced toxicity and fully sustains maximal steroidogenesis. However, this hormone-driven cytoprotection fails against direct GPX4 inhibition by RSL3, indicating an absolute reliance on functional GPX4. These mechanistic findings highlight the paradoxical dual role of ACSL4 in Leydig cell biology and are further supported by bioinformatic analysis of public transcriptomic profiles from infertile patients, which reveal a detrimental imbalance in the ACSL4/GPX4 axis. Together, our data position ferroptosis as a critical disruptor of male endocrine function and reveal a hormone-mediated metabolic adaptation that could inform novel therapeutic strategies against oxidative stress in the testis. Highlights-Leydig cells exhibit a strong vulnerability to ferroptotic cell death. -Ferroptosis disrupts StAR expression and halts Leydig cell steroidogenesis. -hCG signaling promotes metabolic adaptation against Erastin-induced ferroptosis.

Polycystic ovary syndrome (PCOS) is a prevalent endocrine disorder characterized by hyperandrogenism, ovulatory dysfunction, and polycystic ovaries, with granulosa cell dysfunction being a key pathological feature. This study aimed to investigate the role of microRNA-6818-5p in PCOS pathogenesis. Quantitative PCR revealed a significant upregulation of circulating miR-6818-5p in PCOS patients compared to healthy controls. In vitro, functional assays in the human granulosa cell line KGN demonstrated that miR-6818-5p overexpression markedly inhibited cell proliferation (assessed by CCK-8 assay) and promoted apoptosis (measured by Annexin V/PI flow cytometry). Mechanistically, dual-luciferase reporter assay and Western blotting identified HSD17B2 as a direct target of miR-6818-5p, with miR-6818-5p mimics significantly suppressing HSD17B2 protein expression. In conclusion, our findings reveal that elevated miR-6818-5p in PCOS may contribute to follicular development dysfunction by targeting HSD17B2 to disrupt granulosa cell proliferation and apoptosis balance, offering novel insights into PCOS pathology and highlighting miR-6818-5p as a potential diagnostic biomarker and therapeutic target.

Endometriosis is a steroid-dependent gynecologic disease characterized by progesterone (P4) resistance, subfertility/infertility, and pelvic pain; however, the molecular mechanisms underlying impaired P4 responsiveness in endometriosis tissue are not fully understood. RE-1 silencing transcription factor (REST), a transcriptional regulator implicated in steroid hormone signaling, has emerged as a potential mediator of P4 responsiveness. Here, we investigated the role of REST in endometriosis using human tissues and a uterine-specific Rest conditional knockout mouse model. Immunohistochemical analysis of eutopic endometrium and ectopic lesions from patients with endometriosis revealed significantly reduced nuclear REST expression compared with control endometrium, suggesting loss of functional REST in disease. To assess the physiological consequences of REST deficiency, uterine-specific Rest knockout (Rest d/d) mice were generated. Rest d/d females exhibited progressive subfertility and hyper-estrogenic uterine tissue characteristics that displayed a blunted responsiveness to P4 treatment. Loss of Rest selectively altered expression of P4-responsive genes associated with endometriosis pathology, despite preserved P4 receptor expression. Following induction of experimental endometriosis, female mice that developed endometriotic-like lesions using Rest-deficient donor tissue developed significantly larger lesions that were less responsive to P4 treatment compared to lesions induced using control tissue. Mechanical sensitivity was modestly increased in mice receiving Rest-deficient tissue, whereas vaginal hyperalgesia was unaffected. These findings identify loss of nuclear REST as a feature of endometriosis and support a role of REST in subfertility, lesion progression, and blunted response to P4. REST may represent a novel molecular contributor to altered P4 responsiveness and a potential therapeutic target in endometriosis. Significance StatementEndometriosis is a common disease in women characterized by altered steroid hormone signaling, infertility, and pelvic pain. RE-1 silencing transcription factor (REST) is a candidate regulator of steroid hormone signaling in gynecologic disease but a role in endometriosis pathophysiology remains unexplored. To fill this knowledge gap, our study utilizes human endometrial and endometriotic tissues coupled with a conditional knockout mouse model for uterine Rest deficiency. We show that REST is significantly reduced in eutopic and ectopic endometrial tissue from women with endometriosis and that deletion from mouse uterine tissue recapitulates clinical characteristics in women with endometriosis including progesterone resistance, sub-fertility and pelvic pain. These findings will further guide future research to understand impaired steroid signaling in the pathophysiology of endometriosis.

Purpose: Gonadotropin releasing hormone (GnRH) agonists are clinically used to delay pubertal progression by suppressing the hypothalamic-pituitary-gonadal (HPG) axis. While GnRH agonists have long been used clinically, the developmental characterization of HPG axis suppression during puberty remains incompletely understood. Thus, we examined the effects of GnRH receptor agonism in juvenile rats. Hypothesis: Sustained GnRH receptor agonism will result in lower gonadal mass, blunt peripheral pubertal landmarks, and alter hormonal signaling dynamics within the HPG axis. Methods: Animals received a single injection of extended-release leuprolide acetate depot (LA) or vehicle control on postnatal day (PND) 23. Animals were assessed for body mass and peripheral markers of puberty. On PND 44, animals were euthanized and tissues were evaluated to assess additional markers of pubertal maturation, pituitary gene transcript levels, and hormone concentrations in serum and gonads. Results: In females, LA treatment resulted in a smaller gonad size, increased body mass, and less vaginal openings. In males, LA treatment resulted in smaller gonads but did not significantly alter body mass or preputial separation. In the pituitary, LA-treated rats had lower Gnrhr, Fshb, and Lhb transcript levels regardless of sex, while females exhibited higher Cga and Nr5a1. Serum FSH and ACTH were lower in LA-treated animals, and treated females also had lower progestins and androstenedione, and higher LH. Conclusions: LA treatment reduced aspects of pubertal maturation and HPG axis output, with sex specific outcomes. These findings highlight the need for integrated, multi-level approaches to understand how altered GnRH signaling impacts pubertal and long-term physiology.

ObjectivesLow serum testosterone (T) in men with obesity suggesting T deficiency may be misinterpreted by confounding changes in serum SHBG, Ts circulating carrier protein. Measuring or calculating "free" testosterone (FT) concentrations to define a low T is problematic as cFT is not a valid analytical variable lacking certified standard, quality control or reference range. We developed a novel metric, Scaled Testosterone (ST), comparing standardized serum T (LCMS) and SHBG without invoking hypothetical serum T fractions. MethodsSerum T and SHBG in men (n=10,027) pooled from three population-based studies in Australia were expressed as standardized (Z) scores (ZT, ZSHBG) and their difference ST = ZT-ZSHBG. ST was evaluated in a clinical trial of 51 men with severe obesity undergoing 1 year of diet-induced weight loss. ResultsZT and ZSHBG displayed linear correlation (r=0.44, 10-11) with ST approximating zero (-0.33 {+/-}2.14 SD). In non-obese men with low serum T suggestive of organic hypogonadism displayed very low ST indicating ST can evaluate whether a low serum T is proportionate to a concomitant serum SHBG. In men with obesity, low pre-treatment serum T and SHBG both increased during diet-induced weight loss with no change in serum LH while ST which remained within standard limits at each time. ConclusionsThe low serum T in men with obesity may better be considered as the pseudo-hypogonadism of obesity comprising low serum T with proportionately low serum SHBG in the presence of normal serum LH {+/-} FSH serving as a tissue androgen sensor.

Prader-Willi syndrome (PWS) and Schaaf-Yang syndrome (SYS) are neurodevelopmental disorders associated with hypothalamic-pituitary dysregulation. In the pituitary gland, translational control enables rapid peptide hormone production and secretion in response to hypothalamic signals without requiring new mRNA synthesis, yet the mechanisms regulating pituitary translation remain poorly understood. Furthermore, although the PWS-associated gene MAGEL2 has been implicated in neuroendocrine regulation and vesicular trafficking in the hypothalamus, its role in the pituitary gland remains unknown. Initial analysis of previously published pituitary proteomic data revealed enrichment of translation-associated pathways among downregulated proteins in Magel2 KO mice, suggesting translational impairment. Here, we investigated the impact of Magel2 loss on pituitary translatome using polysome profiling and RNA sequencing. We first optimized a polysome profiling workflow for mouse pituitary tissue and established that pooling two to three pituitaries yielded sufficient RNA quality and quantity for downstream analyses. Polysome profiling of WT and Magel2 KO pituitaries revealed no major alterations in global translational activity, as translated and nontranslated fractions were largely unchanged between genotypes. However, transmission electron microscopy revealed a shift toward smaller secretory granule size, indicating altered granule maturation dynamics. To further characterize the pituitary translatome, RNA sequencing was performed on input, monosome, light polysome, and heavy polysome fractions. Clustering analyses identified six distinct translational trajectories across fractions, revealing fraction-specific enrichment of biological pathways. RNAs enriched in heavy polysomes were associated with metabolic and oxidative phosphorylation pathways, whereas monosome-enriched clusters were linked to RNA processing and translation-related functions, suggesting specialized translational regulation within the pituitary. Differential expression analysis demonstrated that translatomic alterations were more pronounced than transcriptomic changes in Magel2 KO pituitaries, with the strongest enrichment observed in heavy polysome fractions. Functional enrichment analyses identified pathways associated with endocrine and metabolic regulation, circadian rhythm, cytoskeleton organization, vesicular trafficking, and RNA regulation, suggesting that translation contributes to pituitary physiological function and patient symptoms. For example, prolactin displayed altered polysome association without changes at the transcript level, consistent with the increased serum prolactin levels observed in Magel2 KO mice and in patients with PWS. Interestingly, the PWS-associated gene Necdin (Ndn) was consistently downregulated across all fractions, which contrasts with previously described compensatory upregulation in the hypothalamus. Together, our findings suggest the involvement of MAGEL2 in pituitary in transcriptional and translational processes and the organization of the secretory pathway and provide the first comprehensive characterization of the mouse pituitary translatome. This work provides new insights into the mechanisms underlying neuroendocrine dysfunction in PWS and SYS and establishes a resource for future studies of translational regulation in neuroendocrine disease.

Pregnancy induces or represses hepatic drug metabolism. Whether pregnancy affects hepatic drug transport is unexplored. We previously showed that a cocktail of pregnancy-related hormones (PRHC) induces mRNA expression and activity of sodium/taurocholate cotransporting polypeptide (NTCP), organic anion transporter 2 (OAT2), and organic cation transporter 1 (OCT1, mRNA only) in differentiated HepaRG cells. Here, using HepaRG cells, we identified cortisol as the hormone primarily responsible for this induction and explored the underlying mechanisms. Clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9-mediated knockdown studies in HepaRG cells showed that the glucocorticoid receptor (GR) is the primary mediator of this response. GR knockdown markedly attenuated cortisol-induced NTCP, OAT2, and OCT1 mRNA expression and activity. Cortisol also induced the mRNA expression of regulatory factors, including pregnane X receptor (PXR), constitutive androstane receptor (CAR), and hepatocyte nuclear factor (HNF) 4 alpha (HNF4). HNF4 knockdown selectively attenuated OAT2 and OCT1 induction, whereas HNF1 knockdown enhanced NTCP induction, attenuated OCT1 induction, and reduced basal organic anion transporting polypeptide 1B1 (OATP1B1) expression. In contrast, knockdown of CAR or PXR did not significantly alter cortisol-mediated transporter regulation. These data identify cortisol as the principal PRH driving regulation of the hepatic OAT2, NTCP, and OCT1 in HepaRG cells and indicate that this response is mediated primarily by GR, with selective downstream contributions from HNF4 and HNF1. These findings provide mechanistic insights into pregnancy-associated changes in hepatic transporter-mediated drug disposition, including when antenatal corticosteroids are administered to pregnant women to prevent respiratory distress syndrome in their prematurely born infants. Significance StatementThe extent and mechanisms by which pregnancy-related hormones regulate hepatic uptake transporters remain poorly defined. This study identifies cortisol as the principal pregnancy-related hormone driving NTCP, OAT2, and OCT1 induction in HepaRG cells and shows that this response is mediated primarily through GR, with transporter-specific contributions from HNF4 and HNF1.

Aims/hypothesisDisruption of the circadian glucocorticoid rhythm occurs in human settings including chronic stress, sleep restriction, circadian misalignment, ageing and autonomous cortisol secretion; in mild autonomous cortisol secretion (MACS) and Cushings syndrome, loss of the normal cortisol trough is clinically informative, and flatter diurnal cortisol profiles are associated with cardiometabolic disease. We previously showed that flattening of glucocorticoid rhythms in mice induces rapid and sustained hyperinsulinemia without hyper or hypo-glycaemia, implying that glucocorticoid rhythms may directly regulate the relationship between circulating glucose and systemic insulin output. Here we tested the hypothesis that beta cell glucocorticoid receptor (GR) signalling is required for the compensatory hyperinsulinaemia that maintains glucose homeostasis during glucocorticoid rhythm flattening, and that this reflects glucocorticoid-dependent reprogramming of beta cell stimulus-secretion coupling. MethodsGlucocorticoid rhythms were flattened in male C57BL/6J mice by subcutaneous corticosterone pellet implantation, which elevates trough levels and reduces peak amplitude while preserving the daily mean hormone concentration. Fasting plasma insulin and blood glucose were measured longitudinally and compared with placebo-implanted controls and high-fat diet-fed mice. Beta cell secretory function was assessed by static and dynamic glucose-stimulated insulin secretion in isolated islets, and beta cell excitability by GCaMP6f Ca{superscript 2} imaging in islets from Ins1-Cre;GCaMP6f mice. To test the requirement for beta cell GR in mature beta cells while avoiding developmental effects of constitutive GR deletion, we generated adult-inducible beta cell-specific GR knockout mice (MIP-CreERT;Nr3c1fl/fl; {beta}GRKO). Combined beta cell and hepatic GR knockout mice (double-GRKO) were used to examine an additional extra-pancreatic contribution to systemic insulin availability. Glucose tolerance and insulin sensitivity were assessed by intraperitoneal glucose and insulin tolerance tests. As a secondary question, a possible contribution of altered insulin clearance was examined from plasma C-peptide:insulin ratios and hepatic insulin-degrading enzyme (IDE) abundance. ResultsGlucocorticoid rhythm flattening produced sustained hyperinsulinaemia with maintained euglycaemia, distinct from the delayed hyperinsulinaemia and hyperglycaemia observed in high-fat diet-fed mice. Islets from glucocorticoid-flattened mice exhibited increased insulin secretion at subthreshold (3 mmol/l) glucose, enhanced secretory responses to stimulatory glucose and increased Ca{superscript 2} responses, indicating a lowered glucose threshold for beta cell activation that persisted ex vivo. Beta cell-specific deletion of GR markedly attenuated the hyperinsulinaemic response to glucocorticoid flattening (insulin AUC reduced [~]40% vs controls; p < 0.001) and produced progressive hyperglycaemia and impaired glucose tolerance, despite unchanged or improved insulin sensitivity. A reduced plasma C-peptide:insulin molar ratio (p = 0.007) and decreased hepatic IDE abundance (p = 0.032) indicated that reduced insulin clearance contributes additionally to the elevated circulating insulin, and combined beta cell and hepatic GR deletion lowered circulating insulin further than beta cell GR deletion alone. The absence of hypoglycaemia despite persistent hyperinsulinaemia is consistent with concurrent insulin resistance. Conclusions/interpretationBeta cell GR signalling is required for the compensatory hyperinsulinaemia that maintains glucose homeostasis when glucocorticoid rhythmicity is disrupted, acting through glucocorticoid-dependent lowering of the glucose threshold for insulin secretion; reduced insulin clearance contributes additionally to the rise in circulating insulin. These findings identify beta cell GR signalling as a key determinant of glucose homeostasis during disrupted glucocorticoid rhythmicity. Clinically, the work is most relevant not simply to nonspecific chronic stress, but to human states in which the cortisol rhythm is measurably flattened or the nocturnal trough is lost, including MACS, Cushings syndrome, sleep restriction, shift work/circadian misalignment and ageing. RESEARCH IN CONTEXTO_ST_ABSWhat is already known about this subject?C_ST_ABSO_LIFlattened or disrupted glucocorticoid rhythmicity in humans is observed most directly in MACS and Cushings syndrome, where loss of the late-night cortisol nadir is clinically informative, and more broadly as flatter salivary cortisol slopes or elevated evening cortisol in ageing, sleep restriction and circadian misalignment; these patterns are associated with type 2 diabetes, cardiovascular disease and mortality. C_LIO_LIFlattening of glucocorticoid rhythms in mice induces rapid and sustained hyperinsulinaemia without hypoglycaemia, indicating that circulating insulin can be elevated independently of glucose. C_LIO_LIHepatic insulin clearance, mediated in part by insulin-degrading enzyme and CEACAM1, is a major determinant of circulating insulin levels. C_LI What is the key question?O_LIHow does disruption of glucocorticoid rhythmicity increase circulating insulin while maintaining glycaemic control, and is beta cell glucocorticoid receptor signalling required for this adaptive response? C_LI What are the new findings?O_LIGlucocorticoid rhythm flattening lowers the glucose threshold for beta cell activation through enhanced Ca{superscript 2} excitability, an effect that persists in isolated islets and indicates in vivo reprogramming of beta cell function. C_LIO_LIBeta cell-specific deletion of the glucocorticoid receptor blunts the hyperinsulinaemic response to glucocorticoid flattening and produces hyperglycaemia and impaired glucose tolerance despite unchanged or improved insulin sensitivity. C_LIO_LIReduced insulin clearance, associated with decreased hepatic insulin-degrading enzyme abundance, contributes additionally to the elevated circulating insulin, but is not required for maintenance of glucose homeostasis. C_LI How might this impact on clinical practice in the foreseeable future?O_LIIdentifying beta cell glucocorticoid receptor signalling as a requirement for glucose homeostasis during disrupted glucocorticoid rhythmicity may inform strategies for understanding hyperinsulinaemia and steroid-associated metabolic dysfunction in human conditions marked by loss of the cortisol trough or flatter diurnal cortisol profiles, particularly MACS, Cushings syndrome, shift work/circadian misalignment and ageing. C_LI

Primary ovarian insufficiency (POI) and related infertility, early menopause, and endocrine disorders due to hormonal deficiency are major side effects in young female cancer patients undergoing cancer therapy. Current strategies preserving the fertility and hormonal functions of the ovary remain imperfect due to concerns of feasibility, efficacy, or safety. Herein, we identified c-Jun N-terminal kinase (JNK) as a pivotal regulator of the DNA damage response (DDR) signaling in oocytes of primordial follicles in response to DNA-damaging cancer therapy. Using pharmacological JNK inhibition and a genetically modified mouse model with oocyte-specific JNK deletion, together with histological, bioinformatic, and molecular approaches, we demonstrated that JNK inhibition prevented chemotherapy-induced oocyte apoptosis and POI, and preserved long-term reproductive cycles and fertility. Mechanistically, JNK was activated in response to chemotherapy-induced DNA damage in oocytes of primordial follicles, causing activation of transcription factor TAp63 and subsequent oocyte apoptosis, ultimately resulting in diminished ovarian reserve and POI. A more clinically relevant breast cancer-bearing mouse model revealed that JNK inhibition preserved the ovarian reserve without compromising anti-cancer efficacy of chemotherapy. Together, our study identifies oocyte-intrinsic JNK as a promising target for developing ovarian protectants and safeguarding reproductive health and fertility in young female cancer survivors.

Psychosocial stressors are key contributors to ovarian functional decline. Chronic unpredictable mild stress (CUMS) is widely used to model stress-induced premature ovarian insufficiency (POI) in mice; however, current animal models do not adequately reflect middle-aged women, who represent a key population exposed to chronic psychosocial stress, nor do they capture the dynamic progression toward POI. Here, female C57BL/6 mice aged 2 or 6 months were subjected to CUMS for 8 or 12 weeks. Estrous cyclicity, endocrine profiles, ovarian histology, and transcriptomic changes in HPO axis-related tissues were systematically analyzed. After 8 weeks of exposure, 2-month-old mice exhibited impaired pituitary responsiveness to estradiol negative feedback, as evidenced by dysregulated FSH secretion, indicating reduced stress tolerance compared with 6-month-old mice. Following 12 weeks of CUMS exposure, both age groups showed significant reductions in ovarian size and follicle numbers across all developmental stages. These findings demonstrate that CUMS induces an age-dependent progression toward POI, with short-term exposure eliciting compensatory phases preceding overt ovarian insufficiency, accompanied by distinct endocrine and reproductive alterations and differential responsiveness of the HPO axis. Transcriptomic analyses revealed age-dependent stress responses: ovaries of 2-month-old mice displayed marked activation of inflammatory and immune-related pathways, whereas 6-month-old mice showed sustained upregulation of protein kinase-related signaling networks. Notably, the 6-month-old CUMS model more closely recapitulates stress-associated reproductive aging in adult women. In briefCUMS has been widely used to establish mouse models of psychosocial stress-induced POI. However, current animal models do not adequately reflect middle-aged women, who represent a key population exposed to chronic psychosocial stress, nor do they capture the dynamic progression toward premature ovarian insufficiency (POI). In this study, we demonstrate that different durations of CUMS exposure induce distinct stages of ovarian dysfunction in both young and middle-aged mice, with short-term exposure driving age-dependent compensatory phases and prolonged exposure leading to overt POI, both accompanied by divergent endocrine and reproductive alterations, alongside age-dependent changes in HPO axis responsiveness to CUMS. Notably, the 6-month-old CUMS model shows greater clinical relevance in recapitulating chronic psychosocial stress and stress-related reproductive aging in adult women.

Pregnancy is a period of extensive metabolic rewiring. Insulin secreting {beta}-cells respond to the metabolic challenges of pregnancy by increasing their mass and size and by altering secretory patterns to maintain glucose homeostasis. If glucose metabolism is not tightly controlled, gestational diabetes may develop. Most studies on {beta}-cell adaptation during pregnancy are derived from rodent models, making translation to the vastly different human gestational setting challenging. In this work, we performed an extensive characterization of pancreatic adaptations throughout porcine pregnancy. Pigs have a long gestational period (114 days) and share a similar size and metabolism to humans, making them an ideal model to bridge the knowledge gap between rodents and humans. By analyzing pancreatic samples from early and late gestational ages, we captured the full trajectory of endocrine remodeling. We observed pregnancy-driven remodeling of endocrine cell types, marked by preferential expansion of pancreatic polypeptide-secreting cells. Proteomic characterization of the pancreas from early and late gestation showed a downregulation of SLC20A2 and ZCCHC7, identifying new protein targets involved in physiological endocrine cell adaptation. Overall, our comprehensive characterization of pancreatic adaptations in the pig model helps bridge the translational gap between rodents and humans and highlights previously unrecognized proteins with therapeutic potential for gestational diabetes.

Adrenal chromaffin cells are key effectors of the sympathoadrenal response and play a central role in the organisms adaptation to environmental and physiological challenges. While cholinergic and pituitary adenylate cyclase-activating polypeptide (PACAP)-dependent mechanisms have long been recognized as major regulators of catecholamine secretion, increasing evidence indicates that connexin-mediated gap junctional communication provides an additional and highly dynamic level of control. Whether early-life experience modifies the adult capacity of chromaffin-cell networks to undergo stress-induced connexin remodeling remains unclear. Here, we examined adrenal medullary connexin expression in adult rats exposed to neonatal maternal separation (MS; 3 h daily, postnatal days 2-15) and later challenged with an 8-day unpredictable mild stress (UMS) protocol. Under basal adult conditions, MS did not produce an overt change in adrenal medullary Cx36 or Cx43 immunoreactivity relative to animal-facility-reared controls. In contrast, UMS increased connexin immunoreactivity in the adrenal medulla, and this response was amplified in animals with a history of MS. MS+UMS animals also displayed enhanced corticosterone responses to acute restraint stress. These findings suggest that neonatal MS does not impose a constitutively altered adult chromaffin-cell phenotype, but instead primes the future stress responsiveness of adrenal medullary connexin remodeling. We propose that chromaffin-cell gap junctions represent a substrate sensitive to stress history, through which developmental experience may influence sympathoadrenal and endocrine adaptation in adulthood.

Mitochondrial homeostasis, governed by the balance between biogenesis and mitophagy, is essential for steroidogenesis in adrenocortical cells. While the requirement of active mitochondria for steroid synthesis is well-established, the hormonal regulation of genes governing mitochondrial function remains poorly understood. This study investigated whether angiotensin II (Ang II) and the cAMP/PKA pathway modulate the expression of key regulatory factors involved in mitochondrial biogenesis and redox status in the human adrenocortical H295R cell line. Using real-time qPCR and Western blot, we show that Ang II and 8Br-cAMP --a permeant analogue of cAMP-- modulate NRF-1, Nrf2, UCP2, and ANT1 impacting on mitochondrial biogenesis, antioxidant defense, and respiratory activity. These molecular changes correlated with increased mitochondrial membrane polarization, as confirmed by MitoTracker red staining. Interestingly, Ang II stimulation promoted a time-dependent increase in TFAM levels, a key transcription factor in mitochondria, which correlates with the increase in mitochondrial DNA (mtDNA) content. The rate of oxygen consumption (OCR) and mitochondrial parameters were determined, with results showing that Ang II led to a significant increase in basal and maximum respiration, ATP production, and proton leak. These findings suggest that hormone stimulation favors mitochondrial activity, thereby enhancing the bioenergetic capacity of adrenocortical cells. Furthermore, treatment with the uncoupler CCCP triggered a retrograde signaling response, upregulating nuclear-encoded mitochondrial genes to counteract mitochondrial membrane depolarization. Our findings demonstrate for the first time that hormonal signals directly modulate the mitochondrial genetic program in H295R human adrenocortical cells, optimizing the bioenergetic platform required for efficient steroidogenic function.

Variants in the human PAX4 gene are associated with both monogenic and complex forms of diabetes, yet their pathogenic effects remain difficult to define in models that accurately mimic human islet architecture and neonatal metabolic transitions. Here, we created a porcine PAX4 loss-of-function model using CRISPR/Cas9 cytidine deaminase base editing to introduce a premature stop codon in the PAX4 coding sequence. PAX4 knockout piglets developed severe hyperglycemia within 24 hours of birth, followed by rapid postnatal clinical deterioration and uniform death by day 3. Biochemical analysis showed significant diabetic decompensation, including electrolyte imbalances, hyperosmolality, azotemia, dyslipidemia, and metabolic acidosis. Gross and histological examinations revealed notable pancreatic hypoplasia with preservation of exocrine tissue. Single-nucleus RNA sequencing and immunohistochemistry demonstrated an almost complete loss of insulin-and somatostatin-producing {beta}-and {delta}-cells, respectively, with relative preservation of glucagon-expressing -cells. Overall, these results establish PAX4 as a crucial factor in pancreatic endocrine development and postnatal glucose regulation in a large-animal model. This platform offers a human-relevant system for studying diabetes-associated PAX4 variants and for testing regenerative and gene-based therapies for insulin-deficient diabetes.

ObjectiveG protein-coupled receptor 180 (GPR180) has been implicated in systemic energy metabolism, primarily in adipose tissue and the liver. Given impaired whole-body glucose tolerance following GPR180 dysfunction, we aimed to determine whether GPR180 regulates pancreatic {beta}-cell function. We investigated whether GPR180 contributes to {beta}-cell insulin secretion by modulating metabolic processes that couple glucose sensing to mitochondrial energy production. MethodsPhenotyping of whole-body (Gpr180 -/-) and {beta} cell-specific Gpr180 (bGpr180-KO) knockout mice was combined with gain- and loss-of-function studies in MIN6 cells. Glucose-stimulated insulin secretion, pancreatic endocrine architecture and identity, transcriptomic and metabolic profiles, as well as mitochondrial function were assessed using in vivo and in vitro approaches, including metabolic challenge tests, histology, RNA sequencing, targeted metabolomics, respirometry, and transmission electron microscopy. ResultsLoss of GPR180 impaired first-phase insulin secretion and glucose tolerance without affecting insulin sensitivity. These defects were {beta}-cell-autonomous, as confirmed in the bGpr180-KO mice and in MIN6 cells. Functional studies revealed that GPR180 regulates mitochondrial substrate utilization, anaplerotic support of the TCA cycle, and ATP generation without affecting glucose uptake or mitochondrial biogenesis. In particular, Gpr180-deficient {beta} cells showed mitochondrial membrane depolarization, reduced oxygen consumption, and endoplasmic reticulum remodeling, altering the local mitochondrial microenvironment. In vivo, Gpr180 deletion in {beta} cells led to downregulation of mitochondrial gene programs in islets, along with altered endocrine cell identity. ConclusionsGPR180 is a previously unrecognized regulator of pancreatic {beta}-cell metabolic competence and identity, linking defects in insulin secretion with alterations in mitochondrial function and endocrine cell identity. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=198 SRC="FIGDIR/small/720098v1_ufig1.gif" ALT="Figure 1"> View larger version (87K): org.highwire.dtl.DTLVardef@1a441ecorg.highwire.dtl.DTLVardef@e41e02org.highwire.dtl.DTLVardef@6e2212org.highwire.dtl.DTLVardef@7ee07a_HPS_FORMAT_FIGEXP M_FIG C_FIG