Endocrinology

It has been documented that variations in glycosylation on glycoprotein hormones, confer distinctly different biological features to the corresponding glycoforms when multiple in vitro biochemical readings are analyzed. We here applied next generation RNA sequencing to explore changes in the transcriptome of rat granulosa cells exposed for 0, 6, and 12 h to 100 ng/ml of four highly purified follicle-stimulating hormone (FSH) glycoforms, each exhibiting different glycosylation patterns: human pituitary FSH18/21 and equine FSH (eqFSH) (hypo-glycosylated), and human FSH24 and chinese-hamster ovary cell-derived human recombinant FSH (recFSH) (fully-glycosylated). Total RNA from triplicate incubations was prepared from FSH glycoform-exposed cultured granulosa cells obtained from DES-pretreated immature female rats, and RNA libraries were sequenced in a HighSeq 2500 sequencer (2 x 125 bp paired-end format, 10-15 x 106 reads/sample). The computational workflow focused on investigating differences among the four FSH glycoforms at three levels: gene expression, enriched biological processes, and perturbed pathways. Among the top 200 differentially expressed genes, only 4 (0.6%) were shared by all 4 glycoforms at 6 h, whereas 118 genes (40%) were shared at 12 h. Follicle-stimulating hormone glycocoforms stimulated different patterns of exclusive and associated up regulated biological processes in a glycoform and time-dependent fashion with more shared biological processes after 12 h of exposure and fewer treatment-specific ones, except for recFSH, which exhibited stronger responses with more specifically associated processes at this time. Similar results were found for down-regulated processes, with a greater number of processes at 6 h or 12 h, depending on the particular glycoform. In general, there were fewer downregulated than upregulated processes at both 6 h and 12 h, with FSH18/21 exhibiting the largest number of down-regulated associated processes at 6 h while eqFSH exhibited the greatest number at 12 h. Signaling cascades, largely linked to cAMP-PKA, MAPK, and PI3/AKT pathways were detected as differentially activated by the glycoforms, with each glycoform exhibiting its own molecular signature. These data extend previous observations demonstrating glycosylation-dependent differential regulation of gene expression and intracellular signaling pathways triggered by FSH in granulosa cells. The results also suggest the importance of individual FSH glycoform glycosylation for the conformation of the ligand-receptor complex and induced signalling pathways.

Non-selective hormone replacement with estradiol improves metabolic homeostasis during menopause. However, this treatment is not recommended for individuals with genetic predisposition to hormone-responsive cancers. In contrast, selective activation of estrogen receptor beta (ER{beta}) has shown promising results, promoting antitumor effects and modulating metabolic outcomes, although mechanisms in which these changes occur remain poorly understood. We investigated the effects of ER{beta} activation using diarylpropionitrile (DPN), a selective ER{beta} agonist, in both an in vivo model of post menopause and in vitro models of metabolic overload. Female Wistar rats were submitted to ovariectomy (OVX) and later treated with DPN. ER{beta} agonist treatment recovered fasting glucose and lipid profiles, improved pancreatic islet morphology, and reduced retroperitoneal white adipose tissue. Serum ketone bodies and free fatty acids levels were also recovered to control levels, suggesting a modulation in liver lipid oxidation. To isolate the direct effects mechanistically, hepatocytes were submitted to nutrient overload and treated with DPN. In vitro, DPN also recovered ketone body secretion and promoted an increased dependence on complete fatty acid oxidation as well as decreased metabolic flexibility, as assessed by modulated extracellular flux analysis. Overall, these findings demonstrate a new role of ER{beta} in the modulation of hepatic lipid and ketone metabolism, with positive metabolic outcomes in estradiol-deficient animals.

Polycystic ovary syndrome (PCOS) is characterized by reproductive and metabolic disturbances and is associated with increased symptoms of anxiety and depression. Circulating adiponectin, an insulin-sensitizing adipokine, is reduced in women with PCOS, and low adiponectin has been linked to impaired mental health, particularly in females. We investigated whether low serum adiponectin is associated with impaired mental health in women with PCOS and whether adiponectin deficiency exacerbates anxiety-like behaviour in a PCOS-like mouse model. Serum adiponectin was measured in women with (n=179) and without PCOS (n=228), stratified by body mass index (BMI). Health-related quality of life was assessed using the SF-36, generating physical and mental component scores. In parallel, the prenatal androgenization (PNA) PCOS-like mouse model was combined with adiponectin-deficient mice (APNhet) to assess the impact of reduced adiponectin on anxiety-like behaviour with and without prenatal androgen exposure. Women with PCOS had lower total and high molecular weight adiponectin levels compared with controls. Adiponectin positively correlated with mental component scores in women with BMI <30, but not in those with obesity. Free testosterone was inversely correlated with adiponectin. In mice, PNA induced anxiety-like behaviour, however, reduced adiponectin did not exacerbate this phenotype. Although APNhet PNA mice showed 65% lower serum adiponectin levels and reproductive dysfunction, they displayed improved metabolic function. Unlike women with PCOS, adult PNA mice were not hyperandrogenic. These findings suggest that adiponectin is associated with mental health in non-obese women, but reduced adiponectin alone does not induce anxiety-like behaviour in the absence of hyperandrogenism. The differing patterns observed across BMI categories, as well as between the human cohort and experimental data, underscore the complexity of the mechanisms underlying mental health disturbances in PCOS.

Polycystic ovary syndrome (PCOS) is a heterogenous reproductive disorder that is often associated with metabolic dysfunction, as well as comorbidities such as pregnancy complications. Although metabolic traits like hyperinsulinemia (i.e., elevated insulin without hypoglycemia) likely exacerbate the reproductive and metabolic features of PCOS, the precise impacts of specific metabolic traits on PCOS pathogenesis, symptom severity, and comorbidity incidence are not known. The aim of our study was to investigate the relationships between insulin levels, PCOS-like traits, and pregnancy complications by limiting endogenous insulin production in a mouse model of PCOS. Using Ins1-null mice with modulated Ins2 gene dosage (Ins1-/-:Ins2+/- versus Ins1-/-:Ins2+/+ littermates), we longitudinally assessed metabolic and reproductive phenotypes in PCOS-like mice generated via prenatal anti-Mullerian hormone (PAMH) exposure. We observed mild reproductive characteristics of PCOS in PAMH mice of both genotypes, including increased anogenital distances, delayed puberty, and disrupted estrous cycling, but did not detect robust PAMH-induced metabolic changes across six months. In the absence of PAMH-aggravated metabolic dysfunction or hyperinsulinemia--even in mice fed a high-fat, high-sucrose diet--reducing Ins2 gene dosage did not notably change most measured traits. However, high-fat, high-sucrose-fed PAMH pregnant dams exhibited a diminished pregnancy-induced insulinogenic response and a trend for reduced {beta}-cell mass compared to control mice, together with superior blood glucose homeostasis despite the physiological challenges of pregnancy. Therefore, while Ins1-null PAMH mice did not manifest pronounced PCOS-like metabolic features, prenatal AMH exposure can cause shifts in metabolic homeostasis during pregnancy.

Androgen excess is one of the most common endocrine disorders of reproductive-aged women, affecting up to 20% of this population. Women with elevated androgens often exhibit hyperinsulinemia and insulin resistance. The mechanisms of how elevated androgens affect metabolic function are not clear. Hyperandrogenemia in a dihydrotestosterone (DHT)-treated female mouse model induces whole body insulin resistance possibly through activation of the hepatic androgen receptor (AR). We investigated the role of hepatocyte AR in hyperandrogenemia-induced metabolic dysfunction by using several approaches to delete hepatic AR via animal-, cell-, and clinical-based methodologies. We conditionally disrupted hepatocyte AR in female mice developmentally (LivARKO) or acutely by tail vein injection of an adeno-associated virus with a liver-specific promoter for Cre expression in ARfl/fl mice (adLivARKO). We observed normal metabolic function in littermate female Control (ARfl/fl) and LivARKO (ARfl/fl; Cre+/-) mice. Following chronic DHT treatment, female Control mice treated with DHT (Con-DHT) developed impaired glucose tolerance, pyruvate tolerance, and insulin tolerance, not observed in LivARKO mice treated with DHT (LivARKO-DHT). Further, during an euglycemic hyperinsulinemic clamp, the glucose infusion rate was improved in LivARKO-DHT mice compared to Con-DHT mice. Liver from LivARKO, and primary hepatocytes derived from LivARKO, and adLivARKO mice were protected from DHT-induced insulin resistance and increased gluconeogenesis. These data support a paradigm in which elevated androgens in females disrupt metabolic function via hepatic AR and insulin sensitivity was restored by deletion of hepatic AR.

Poor ovarian responders (POR) are women undergoing in-vitro fertilization who respond poorly to ovarian stimulation, resulting in the retrieval of lower number of oocytes, and subsequently lower pregnancy rates. The follicular fluid (FF) provides a crucial microenvironment for the proper development of follicles and oocytes. Conversely, dysregulated FF metabolome and cytokinome could have detrimental effects on oocytes in POR. Androgens such as dehydroepiandrosterone (DHEA) have been proposed to alter the POR follicular microenvironment but its effects on the FF metabolome and cytokine profiles is unknown. In this study, untargeted LC-MS/MS metabolomics was performed on FF of POR patients with DHEA supplementation (DHEA+) and without (DHEA-) in a randomized clinical trial (N=52). Untargeted metabolomics identified 118 FF metabolites of diverse chemistries, which included lipids, steroids, amino acids, hormones, among others. FF metabolomes were different between DHEA+ and DHEA- groups. Specifically, glycerophosphocholine, linoleic acid, progesterone, and valine were significantly lower in DHEA+ relative to DHEA-. Among cytokines, MCP1, IFN{gamma}, LIF and VEGF-D were significantly lower in DHEA+ relative to DHEA. Collectively, our data suggest a role of DHEA on these metabolic and cytokines pathways, and these FF metabolites could be used to guide future studies in DHEA supplementation regimen.

Women with polycystic ovary syndrome (PCOS) exhibit sustained elevation in circulating androgens during pregnancy, an independent risk factor linked to pregnancy complications and adverse neonatal outcomes. Yet, further investigation is required to understand the precise mechanisms and the impact on cell-type specific placental dysfunction. To explore these dynamics, a PCOS-like mice model was induced with continuous androgen exposure throughout pregnancy, mimicking the human-PCOS. This resulted in impaired placental and embryonic development, leading to mid-gestation lethality. Co-treatment with the androgen receptor blocker, flutamide, prevented this lethality. Comprehensive analysis using whole-genome bisulfite and RNA sequencing revealed the diminished proportion of trophoblast precursors by downregulation of Cdx2. The absence of Gcm1, Synb, and Prl3b1 further resulted in decreased numbers of syncytiotrophoblasts and sinusoidal trophoblast giant cells, leading to observed compromised placenta labyrinth formation. Importantly, human trophoblast organoids exposed to androgens exhibited analogous alterations, highlighting impaired trophoblast differentiation as a key feature in PCOS-related pregnancy complications. Remarkably, all effects were mediated through the androgen receptor pathways, as demonstrated by comparable offspring phenotypes to controls when treated with flutamide. These findings provide novel insight into the PCOS-related pregnancy complications, and potential cellular targets for future treatment.

Evidence suggests that estradiol-sensing preoptic area GABA neurons are involved in the pre-ovulatory surge mechanism necessary for ovulation. In vivo CRISPR-Cas9 editing was used to achieve a 60-70% knockdown in estrogen receptor alpha (ESR1) expression by GABA neurons located within the region of the rostral periventricular of the third ventricle (RP3V) and medial preoptic nuclei (MPN) in adult female mice. Mice exhibited variable reproductive phenotypes with the only significant finding being those mice with bilateral ESR1 deletion in RP3V GABA neurons that had reduced cFos expression in GnRH neurons at the time of the surge. One sub-population of RP3V GABA neurons expresses kisspeptin. Re-grouping ESR1-edited mice on the basis of their RP3V kisspeptin expression revealed a highly consistent phenotype; mice with a near complete loss of kisspeptin immunoreactivity displayed constant estrus and failed to exhibit surge activation but retained pulsatile LH secretion. These observations demonstrate ESR1-expressing GABA-kisspeptin neurons in the RP3V are essential for the murine preovulatory LH surge mechanism.

Pancreatic islets adapt to insulin resistance of pregnancy by up regulating {beta}-cell proliferation and increase insulin secretion. Previously, we found that prolactin receptor (Prlr) signaling is important for this process, as heterozygous prolactin receptor-null (Prlr+/-) mice are glucose intolerant, had a lower number of {beta} cells and lower serum insulin levels than wild type mice during pregnancy. However, since Prlr expression is ubiquitous, to determine its {beta}-cell specific effects, we generated a transgenic mouse with a floxed Prlr allele under the control of an inducible promoter, allowing conditional deletion of Prlr from {beta} cells in adult mice. In this study, we found that {beta}-cell-specific Prlr reduction resulted in elevated blood glucose during pregnancy. Similar to our previous finding in mouse with global Prlr reduction, {beta}-cell-specific Prlr loss led to a lower {beta}-cell mass and a lower in vivo insulin level during pregnancy. However, these islets do not have an intrinsic insulin secretion defect when tested in vitro. Interestingly, when we compared the islet gene expression profile, using islets isolated from mice with global versus {beta}-cell-specific Prlr reduction, we found some important differences in genes that regulate apoptosis and insulin secretion. This suggests that Prlr has both cell-autonomous and non-cell-autonomous effect on {beta} cells, beyond its regulation of pro-proliferative genes.

Hashimotos thyroiditis is an autoimmune thyroid disease characterized by hypothyroidism and a high level of anti-thyroid autoantibodies. This disease has been linked to a negative impact on female fertility, but the mechanisms are unclear. Ovarian follicular fluid appears to be the key to understanding how Hashimotos thyroiditis can affect fertility. Therefore, we aimed to evaluate the follicular fluid metabolic profile and its relationship with anti-thyroid autoantibody levels. For this, we collected follicular fluid from a total of 61 patients undergoing in vitro fertilization treatment, comprising 34 women with thyroid autoantibody positivity and 18 negative controls. Follicular fluid samples were analysed using metabolomics and thyroid autoantibodies were measured. Follicular fluid samples from Hashimotos thyroiditis patients presented 15 metabolites with higher concentrations than those in controls, which indicates five possible affected pathways: the glycerophospholipid, arachidonic acid, linoleic acid, alpha-linolenic acid, and sphingolipid metabolism pathways. These pathways are known to regulate ovarian functions. In addition, anti-thyroglobulin antibody concentrations were more than tenfold higher in women with Hashimotos thyroiditis than in controls, in both serum and follicular fluid. Our data showed that Hashimotos thyroiditis can change the metabolic profile of follicular fluid, suggesting a potential mechanistic explanation for the association of this disease with female infertility.

To induce ovulation, neural circuits are sequentially activated by estradiol and progesterone. In female rodents, estradiol-induced neuroprogesterone, synthesized in astrocytes, is essential for the luteinizing hormone (LH) surge and subsequently, ovulation. However, the gonadotropin-releasing hormone (GnRH) neurons do not express the steroid receptors necessary for reproduction: progesterone receptors (PGR) or estrogen receptor- (ER). Steroid information is transduced by rostral periventricular (RP3V) kisspeptin neurons that express ER and PGR and innervate GnRH neurons in the diagonal band of Broca (DBB) and the medial septum. In this study, we tested the hypothesis that estradiol induced neuroprogesterone needed for the LH surge is mediated by kisspeptin. Neuroprogesterone synthesis was inhibited with aminoglutethimide (AGT; s.c.) in 17{beta}-estradiol benzoate (EB)-primed, ovariectomized (ovx) and adrenalectomized (adx) rats. Kisspeptin-10 (20 nmol/{micro}l) was infused into the DBB, trunk blood was collected 53 hours post-EB injection, and serum LH levels were analyzed by ELISA. AGT inhibition of neuroprogesterone synthesis blocked the EB-induced LH surge. Subsequent treatment with either progesterone or DBB kisspeptin-10 infusion restored the LH surge. Kisspeptin restored the LH surge, which was blocked by DBB infusion of kisspeptin receptor (GPR54) antagonist (kisspeptin-234). Finally, knockdown of kisspeptin protein levels in the RP3V with kisspeptin antisense oligodeoxynucleotide (ODN) significantly lowered LH levels in EB-primed rats compared to scrambled ODN, demonstrating the importance of endogenous RP3V kisspeptin for the LH surge. These results support the hypothesis that neuroprogesterone induces both kisspeptin release from RP3V neurons impacting the LH surge.

Maternal nutrition before conception is recognised as a determinant of offspring development; however, the behavioural and neuroendocrine consequences of preconception calorie restriction (CR) remain poorly understood. This study isolated the preconception window to examine how different CR patterns, stable (25% reduction; CR-25%), unpredictable deprivation (CR-A), and variable (25-75% fluctuation; CR-V), affect adult offspring outcomes. Male and female progeny from preconception CR female Wistar rats were assessed across domains sensitive to early-life programming, including anxiety- and depression-like behaviour, coping style, socio-sexual behaviour, and hypothalamic-pituitary-gonadal (HPG) axis activity. Preconception CR produced sex- and diet-specific effects. Females exhibited transient reductions in exploratory behaviour and more active coping styles, particularly CR-25% and CR-V animals. In males, all CR regimens enhanced copulatory behaviour and reduced aggression toward females. Endocrine profiling revealed divergent HPG responses: CR-A males showed elevated basal faecal testosterone metabolites (fTM) but reduced basal serum testosterone, whereas CR-V males exhibited blunted androgenic reactivity post-social provocation. These findings demonstrate that maternal preconception CR can program male offspring toward a prosocial, sexually motivated phenotype and female offspring toward an enhanced coping style, underscoring this period as a sensitive window for shaping behavioural and endocrine trajectories.

Desert Hedgehog (Dhh) mutations cause Leydig cell dysfunction, yet the mechanisms governing Leydig lineage commitment through Dhh-mediated receptor selectivity, transcriptional effector specificity, and steroidogenic coupling remain elusive. In this study, using CRISPR/Cas9-mediated gene knockout and stem Leydig cells (SLCs) transplantation, we identified a critical Dhh/Patched 2 (Ptch2)/Glioma-associated oncogene homolog 1 (Gli1)/steroidogenic factor 1 (Sf1) signaling axis essential for SLC differentiation in Nile tilapia (Oreochromis niloticus). Dhh deficiency resulted in defective adult Leydig cells and androgen insufficiency. Rescue experiments involving 11-ketotestosterone administration and a Dhh agonist treatment, combined with SLCs transplantation, demonstrated that Dhh regulates SLC differentiation, not survival. In vitro knockout of ptch1 and ptch2 in SLCs revealed that Ptch2 likely acts as the functional receptor for Dhh. This was further supported by in vivo genetic rescue experiments, where ptch2 mutation did not impair testicular development, yet completely rescued the testicular defects in dhh mutants--consistent with Ptch2 acting as an inhibitory receptor whose loss alleviates Dhh pathway suppression. Luciferase assays in Gli-knockout SLCs demonstrated that Gli1 acts as the primary transcriptional effector, and transactivates sf1 expression. Additionally, functional transplantation assays confirmed that Sf1 is indispensable for SLCs differentiation, as Sf1-overexpressing SLCs rescued differentiation, whereas sf1-mutant SLCs failed. Overall, our work delineates the Dhh-Ptch2-Gli1-Sf1 axis and provides fundamental insights into the endocrine regulation of Leydig cell lineage development. HighlightsO_LIDhh regulates the differentiation of SLCs rather than their survival C_LIO_LIPtch2 acts as the functional receptor for Dhh signaling in SLCs C_LIO_LIGli1 is the principal transcriptional activator for Dhh signaling in SLCs C_LIO_LISf1 is the critical downstream effector of Gli1 in SLCs differentiation C_LI

The prohibitively low yield of fertilizable oocytes obtained from cultured ovarian follicles limits clinical translation of in vitro follicle maturation for fertility preservation. This is in part due to an incomplete understanding of the process of follicle development. Previous work has demonstrated that group culture of primary murine follicles had a synergistic effect on growth and maturation in contrast to single follicles, but mechanisms remained unknown. Here, we cultured primary follicles in groups of 5 (5X) or 10 (10x) for twelve days, separated the somatic cells from oocytes, and analyzed the temporal transcriptional signatures every two days. In total, 13,461 genes in somatic cells and 10,091 genes in oocytes were computationally sorted into ten temporally distinct gene expression patterns. The somatic cell temporal gene expression patterns showed strong concordance with the granulosa and theca cell markers reported in a recent single-cell whole ovary RNA sequencing study. Importantly, canonical markers of steroidogenesis in cultured follicles followed expected trajectories of decreasing Amh expression and increasing Inhba, Inhbb, Cyp11a1, Cyp17a1, Cyp19a1, Lhcgr, and Fshr over the culture period. Furthermore, when comparing the 10X and 5X culture groups, we identified 306 and 14 differentially expressed genes in somatic cells and oocytes, respectively. Shotgun proteomics data was aligned with the somatic cell transcriptomic data and identified four L-R pairs that were differentially expressed between the two conditions. These comprehensive datasets uncovered temporal dynamics of in vitro folliculogenesis in a compartment-specific manner, serving as a valuable resource for optimizing future follicle culture systems for fertility preservation.

Early detection of ovulation and pregnancy in the common marmoset is crucial for reproductive studies, yet hCG kits lack cross-reactivity with marmoset CG, and current methods remain labor-intensive. Here, we developed monoclonal antibodies against marmoset CG and CG{beta}, and established a non-invasive immunochromatographic CG assay. By eliminating invasive blood sampling, this assay supports 3Rs principles and enables practical endocrine monitoring. The assay detected urinary CG surges preceding ovulation, enabling efficient embryo recovery through artificial insemination (75%). Early pregnancy was detected at approximately 17 days post-ovulation. In addition, pregnancy detection in squirrel monkeys suggests conservation of CG features among certain New World primates. Overall, this simple, non-invasive assay provides a practical tool for marmoset research and establishes a foundation for future conservation-oriented reproductive monitoring following appropriate species-specific validation.

The steroid hormone progesterone, acting through its nuclear progesterone receptor (PR), has complex physiologic activities with different levels of hormones manifesting distinct and sometimes opposing phenotypic responses in target tissues. However, most of what is currently known about the transcriptional activity of PR comes from studies performed using progestins at levels that are in the high physiologic range ([&ge;]10nM), relevant only in the luteal phase of the reproductive cycle and pregnancy in humans. These studies do not consider the non-linearity of responses to progestins that exist in physiology and are not informative as to the mechanisms by which low levels of progestins, as occurs during menopause, exert their biological activities. Thus, we undertook to define the mechanisms which enable cells to recognize and respond to different levels of progestins. Using a PR expressing cell model of luminal breast cancer (T47D cells) we demonstrated that low concentration progestins (0.1-0.3nM) drive proliferation while high dose progestins ([&ge;]10nM) inhibit proliferation. Using both unbiased and targeted approaches, we found that low dose progestins facilitate cell cycle entry by enhanced expression of CCND1 and SGK1, which are both required to initiate a signaling cascade that leads to increased phospho-Rb and E2F1 transcriptional activity. CCND1 cooperates with CDK4/6 to phosphorylate Rb, while SGK1 phosphorylates p21, thereby excluding it from the nucleus and inhibiting its anti-proliferative function. Expression of CCND1 and SGK1 mRNAs are primary responses to low dose progestin treatment. However, these responses occur at very low levels of receptor occupancy and in the absence of receptor phosphorylation events that have been shown to be required for nuclear translocation and transcriptional activity. These findings challenge the assumption of linearity in response to progestin dose. Further, they suggest that concentrations of progestins found in post-menopausal women (0.1-0.3nM) have the potential to exert proliferative responses in PR expressing cancers.

Neural circuits in female rats are exposed to estradiol and sequential progesterone to regulate the luteinizing hormone (LH) surge and thus ovulation. Estradiol induces progesterone receptors (PGRs) in rostral periventricular region of the third ventricle (RP3V) kisspeptin neurons, and positive feedback estradiol concentrations induce neuroprogesterone (neuroP) synthesis in hypothalamic astrocytes that signal to PGRs expressed in kisspeptin neurons to trigger the LH surge. We tested the hypothesis that neuroP-PGR signals through Src family kinase (Src) to trigger the LH surge. As in vitro, PGR and Src are co-expressed in RP3V neurons. Estradiol treatment increased the number of PGR immunopositive cells and PGR and Src colocalization. Infusion of the Src inhibitor (PP2) into the RP3V, attenuated the LH surge measured by ELISA in trunk blood collected 53 hours post-EB injection. While PP2 reduced the LH surge in 50 g EB treated ovariectomized/adrenalectomized (ovx/adx) rats, activation of either PGR or Src in 2g EB primed animals significantly elevated LH concentrations compared with DMSO treated ovx/adx rats. These results support the importance of Src in the estradiol and neuroP triggering of the LH surge.

Roundabout guidance receptor 1 (Robo1) is known to function during midbrain development in mice, but its postnatal role remains poorly defined in part due to the perinatal lethality of the mice lacking the gene. Here, we describe the postnatal phenotypes of Robo1-/- mice in the B6/129s genetic background. Robo1-/- mice had both a slower growth rate and shorter lifespan compared to Robo1+/+ littermates. Skin histological analysis revealed that Robo1-/- mice displayed increased wrinkles, enlarged sebaceous glands, and a reduced subcutaneous fat layer. Robo1-/- mice displayed accelerated hair graying in line with an observed overall decrease in melanin production. Although both growth hormone (GH) and insulin-like growth hormone 1 (IGF-1) were suppressed in Robo1-deficient mice at 3 weeks of age, they were expressed at similar levels to Robo1 intact mice at 7 weeks of age. These findings suggest that Robo1-mediated hormone regulation is required for normal growth during the early stages of puberty and may provide a crucial timepoint at which to examine the molecular mechanisms of pituitary disorders.

Type 2 diabetes (T2D) arises in the context of obesity and overnutrition; however, additional demographic features including age and biological sex contribute to T2D risk. Estradiol (E2) is thought to play a protective metabolic role that may govern sex differences in the development of T2D. The mechanisms by which E2 exerts these effects and the impact of reduced E2 signaling in {beta} cells during menopause remain incompletely understood. We analyzed publicly available whole islet transcriptome datasets from female and male cadaveric donors and showed significant age-related modulation of gene expression, including changes in pathways related to {beta} cell function, in islets from female donors. Importantly, these patterns were not observed in islets from male donors. To test the in vivo relationship between E2 signaling and {beta} cell function, 10-week- old female C57BL6/J mice underwent an ovariectomy (OVX) or sham (CTR) surgery, followed by 4 weeks of high-fat diet (HFD) treatment. HFD-OVX mice exhibited obesity-induced glucose intolerance, increased cell mass, and reduced expression of {beta} cell identity markers. Furthermore, ex vivo treatment of islets with the G protein coupled estrogen receptor (GPER)- specific agonist G-1 restored {beta} cell identity gene expression. Together, these data identify a novel connection between GPER signaling and {beta} cell identity and suggest that menopausal loss of E2 signaling through GPER may be linked with loss of {beta} cell identity.

Pituitary thyrotropes are specialized cells that produce thyroid stimulating hormone (TSH), a critical factor for growth and maintenance of metabolism. The transcription factors POU1F1 and GATA2 have been implicated in thyrotrope fate and transcriptional regulation of the beta subunit of TSH, Tshb, but no transcriptomic or epigenomic analyses of these cells has been undertaken. The goal of this work was to discover key transcriptional regulatory elements that drive thyrotrope fate. We identified the transcription factors and epigenomic changes in chromatin that are associated with differentiation of POU1F1-expressing progenitors into thyrotropes, a process modeled by two cell lines: one that represents an early, undifferentiated Pou1f1 lineage progenitor (GHF-T1) and one that is a committed thyrotrope that produces TSH (TT1). We generated and compared RNA-seq, ATAC-seq, histone modification (including H3K27Ac, H3K4Me1, and H3K27Me3), and transcription factor (POU1F1) binding in these two cell lines to identify regulatory elements and candidate transcriptional regulators. We identified POU1F1 binding sites that were unique to each cell line. POU1F1 binding sites are commonly associated with bZIP transcription factor consensus binding sites in GHF-T1 cells and Helix-Turn-Helix (HTH) or basic Helix-Loop-Helix (bHLH) factors in TT1 cells, suggesting that these classes of transcription factors may recruit or cooperate with POU1F1 binding to unique sites. We validated enhancer function of novel elements we mapped near Cga, Pitx1, Gata2, and Tshb by transfection in TT1 cells. Finally, we confirmed that an enhancer element near Tshb can drive expression in thyrotropes of transgenic mice, and we demonstrate that GATA2 enhances Tshb expression through this element. These results extend the ENCODE multi-omic profiling approach to an organ that is critical for growth and metabolism, which should be valuable for understanding pituitary development and disease pathogenesis.