Although it is known that prenatal maternal stress (PNMS) has negative influence on nervous system development in offspring, there has been no solid evidence showing the effect of PNMS on early neurogenesis during development. In this study, we established a chick embryo model to investigate how PNMS affects early neurogenesis by mimicking an intrauterine environment with high dexamethasone (Dex) levels. The results showed that Dex-mimicked PNMS significantly suppressed the development of gastrula embryos and increased the risks of neural tube defects and cranial deformity. Using immunofluorescence staining and Western blots to determine the expression levels of pHIS3, PCNA/Sox2, we found that PNMS significantly inhibited the proliferation of neural progenitor cells, and the downregulation of TGFβ signaling pathway might be responsible for the inhibition. Furthermore, immunofluorescence staining and Western blots manifested that PNMS could suppress the differentiation of neural progenitor cells to neuronal lineages, but promote them to transform into neuroglial cells, which might be due to the restriction of expressions of key genes (BMP4, SHH, Wnt3a, Slug, and Msx1) related to neural differentiation. In summary, our data reveal that PNMS dramatically impacts the earliest stages of neural development, thereby greatly increasing the risk of physical and mental health problems in childhood or adulthood.

Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) and the dual GLP-1 and glucose dependent insulinotropic polypeptide (GIP) receptor co-agonist tirzepatide (referred to here collectively as "GLP-1-based therapy") are incretin-based therapies being used increasingly in the management of both type 2 diabetes (T2D) and obesity. They are now recognized to have beneficial effects beyond improved glycemic control and weight loss, including cardiovascular and renal protection. GLP-1-based therapy also slows gastric emptying, which has benefits (lowering postprandial glucose), but also potential risks (e.g. hypoglycemia in individuals on insulin or sulphonylurea therapy). Their effects on the gallbladder may also be beneficial, contributing to reducing postprandial triglycerides, but they also potentially increase the risk of biliary disease. In this review, we summarize the effects of GLP-1 and incretin-based therapeutics on gastric, biliary and small intestinal function. An improved understanding of these effects will optimize the use of these drugs.

The importance of hormones in mediating a behavioural transition in mammals from a virgin or non-parenting state to parental state was established around 50 years ago. Extensive research has since revealed a highly conserved neural circuit that underlies parental behaviour both between sexes and between mammalian species. Within this circuit, hormonal action in the medial preoptic area of the hypothalamus (MPOA) has been shown to be key in timing the onset of parental behaviour with the birth of offspring. However, the mechanism underlying how hormones act in the MPOA to facilitate this change in behaviour has been unclear. Technical advances in neuroscience, including single cell sequencing, novel transgenic approaches, calcium imaging, and optogenetics, have recently been harnessed to reveal new insights into maternal behaviour. This review aims to highlight how the use of these tools has shaped our understanding about which aspects of maternal behaviour are regulated by specific hormone activity within the MPOA, how hormone-sensitive MPOA neurons integrate within the wider neural circuit that governs maternal behaviour, and how maternal hormones drive changes in MPOA neuronal function during different reproductive states. Finally, we review our current understanding of hormonal modulation of MPOA-mediated paternal behaviour in males.

Significant research interest has been focused on beige adipocytes, activation of which improves glucose and lipid homeostasis, therefore representing new therapeutic opportunities for metabolic diseases. Various Cre/Lox-based strategies have been used to investigate the developmental history of beige adipocytes and how these cells adapt to environmental changes. Despite the significant advancement of our understanding of beige adipocyte biology, much of the molecular insights of the beige adipocyte, including its origin, cell type specific function, remain to be further illustrated. It has previously been shown that Chrna2 (cholinergic receptor nicotinic alpha 2 subunit) has selective functionality in beige adipocytes. In this study, we explore the Chrna2-Cre-driven reporter expression in mouse beige adipocytes in vivo and in vitro. Our findings indicate that Chrna2-Cre expression is present selectively in multiple locular beige adipocytes in subcutaneous inguinal white adipose tissue (iWAT) and differentiated stromal vascular fraction from iWAT. Chrna2-Cre expression was detected in iWAT of young pups and mice after cold exposure where significant number of beige adipocytes are present. Chrna2-Cre driven reporter expression is permanent in iWAT post labeling and can be detected in iWAT of adult mice or mice that have been housed extensively at thermoneutrality after cold exposure, even though only "inactive dormant" beige adipocytes are present in these mice. Chrna2-Cre expression can also be increased by rosiglitazone treatment and β-adrenergic activation. This research, therefore, introduces the Chrna2-Cre line as a valuable tool for tracking the development of beige adipocytes and investigate beige fat function.

Thyroid hormone receptors (TRs) are essential components of the endocrine system, mediating the cellular effects of thyroid hormones. The two TR genes, THRA and THRB, encode four isoforms, with TRα1 and TRβ1 being the most prevalent. TRs are ligand-dependent transcription factors and members of the nuclear receptor superfamily, indispensable for human growth, development and metabolism. Dysfunctional TR signaling can lead to conditions like resistance to thyroid hormone (RTH) syndrome, thyroid cancer, and metabolic disorders. Structurally, TRs comprise several domains: a variable N-terminal domain, a conserved DNA-binding domain, and a ligand-binding domain that mediates interaction with hormones and transcriptional coregulators. TRs predominantly function as heterodimers with the retinoid X receptor (RXR), binding to thyroid hormone response elements (TREs) in target genes to regulate their transcription. This review examines the structural studies on TRs, primarily performed through X-ray crystallography, that have provided detailed insights into TR functions, including DNA recognition, ligand binding, and coregulator interactions. We also discuss how these findings have deepened our understanding of TR mechanisms and contributed to the interpretation of pathogenic mutations.

The melanocortin system is fundamental to neural control of energy balance and long-term weight regulation. Recent evidence shows that melanocortins also act at peripheral tissues to regulate metabolism, independent of the brain or the sympathetic nervous system (SNS). One such target is skeletal muscle, which contributes to energy expenditure through changes in adaptive thermogenesis. We aimed to determine 1. whether direct femoral infusion of αMSH could increase muscle heat production independent of SNS activation and 2. if α-MSH-induced skeletal muscle heat production was associated with altered mitochondrial function. Dataloggers were implanted into one hind-leg of ovariectomised ewes and set to record vastus lateralis temperature every 15 mins. A cannula was inserted into one femoral artery for infusion of either αMSH (0.1 μg/ h) or saline. Femoral infusion of αMSH increased (P<0.0001) skeletal muscle heat production, without effect on food intake. State 4 respiration increased (P<0.05) and the respiratory control ratio decreased (P<0.05) in mitochondria isolated from αMSH-treated animals. In addition, femoral infusion of αMSH reduced plasma glucose concentration in the femoral, but not the jugular vein; there was no effect of αMSH treatment on non-esterified fatty acid concentrations. These data suggest that αMSH can act locally to increase glucose uptake. We further show that blockade of the α- and β-adrenergic limbs of the SNS with either phentolamine or propranolol infusion, had no effect on αMSH-induced skeletal muscle heat production. Overall, we show that αMSH acts directly at skeletal muscle to promote glucose uptake and increase energy expenditure via mitochondrial thermogenesis.

Normal ovarian function requires the expression of estrogen receptors α (ESR1) and β (ESR2) in distinct cell types within the ovary. The double estrogen receptor knockout (αβERKO) ovary had the appearance of seminiferous tubule-like structures that expressed SOX9, this phenotype was lost when the animals were repeatedly backcrossed to the C57BL/6J genetic background. A new line of ERKO mice, Ex3αβERKO, was developed for targeted disruption on a mixed genetic background. Histological examination of the ovaries in the Ex3αβERKO showed the appearance of seminiferous tubule-like structures in mice aged 6-12 months. These dismorphogenic regions have cells that no longer express granulosa cell specific FOXL2, while other cells express Sertoli-cell specific SOX9 as examined by immunohistochemistry. Whole ovarian gene expression analysis in Ex3αERKO, Ex3βRKO, and Ex3αβERKO found many genes differentially expressed compared to controls with one Esr1 and Esr2 allele. The genes specific to the Ex3αβERKO ovary were compared to other models of postnatal ovarian transdifferentiation identifying 21 candidate genes. To examine the genetic background contributions, DNA was isolated from αβERKO mice that did not show ovarian transdifferentiation and compared to DNA from Ex3αβERKO using the Mouse Diversity Array. A genomic region putatively associated with transdifferentiation was identified on Chr18 (5M-15M) and genes in this region were compared to the genes differentially expressed in models of ovarian transdifferentiation. This work demonstrates the importance of ESRs in maintaining granulosa cell differentiation within the ovary, identifies several potential gene candidates and suggests that genetic background can be a confounding factor.

High neonatal growth hormone (GH) secretion has been described in several species. However, the neuroendocrine mechanisms behind this surge remain unknown. Thus, the pattern of postnatal GH secretion was investigated in mice and rats. Blood GH levels were very high on postnatal day (P)1 and progressively decreased until near zero by P17 in C57BL/6 mice without sex differences. This pattern was similar to that observed in rats, except that female rats showed higher GH levels on P1 than males. In comparison, follicle-stimulating hormone exhibited higher secretion in females during the first 3 weeks of life. Hypothalamic Sst mRNA and somatostatin neuroendocrine terminals in the median eminence were higher in P20/P21 mice than in newborns. Knockout mice for GH-releasing hormone (GHRH) receptor showed no GH surge, whereas knockdown mice for the Sst gene displayed increased neonatal GH peak. Leptin deficiency caused only minor effects on early-life GH secretion. GH receptor ablation in neurons or the entire body did not affect neonatal GH secretion, but the subsequent reduction in blood GH levels was attenuated or prevented by these genetic manipulations, respectively. This phenotype was also observed in knockout mice for the insulin-like growth factor-1 (IGF-1) receptor in GHRH neurons. Moreover, glucose-induced hyperglycemia overstimulated GH secretion in neonatal mice. In conclusion, GH surge in the first days of life is not regulated by negative feedback loops. However, neonatal GH secretion requires GHRH receptor, and is modulated by somatostatin and blood glucose levels, suggesting that this surge is controlled by hypothalamic-pituitary communication.

Fibroblast growth factor 23 (FGF23) is a bone-secreted protein widely recognized as a critical regulator of skeletal and mineral metabolism. However, little is known about the nonskeletal production of FGF23 and its role in tissues other than bone. Growing evidence indicates that circulating FGF23 levels rise with a high-fat diet (HFD) and they are positively correlated with body mass index (BMI) in humans. In the present study, we show for the first time that increased circulating FGF23 levels in obese humans correlate with increased expression of adipose Fgf23 and both positively correlate with BMI. To understand the role of adipose-derived Fgf23, we generated adipocyte-specific Fgf23 knockout mice (AdipoqFgf23Δfl/Δfl) using the adiponectin-Cre driver, which targets mature white, beige, and brown adipocytes. Our data show that targeted ablation of Fgf23 in adipocytes prevents HFD-fed female mice from gaining body weight and fat mass while preserving lean mass but has no effect on male mice, indicating the presence of sexual dimorphism. These effects are observed in the absence of changes in food and energy intake. Adipose Fgf23 inactivation also prevents dyslipidemia, hyperglycemia, and hepatic steatosis in female mice. Moreover, these changes are associated with decreased respiratory exchange ratio and increased brown fat Ucp1 expression in knockout mice compared to HFD-fed control mice (Fgf23fl/fl). In conclusion, this is the first study highlighting that targeted inactivation of Fgf23 is a promising therapeutic strategy for weight loss and lean mass preservation in humans.

Genome-wide association studies (GWAS) in humans and livestock have identified genes associated with metabolic traits. However, the causality of many of these genes on metabolic homeostasis is largely unclear due to a lack of detailed functional analyses. Here we report ligand-dependent corepressor-like (LCoRL) as a metabolic regulator for body weight and glucose homeostasis. Although GWAS data show that LCoRL is strongly associated with body size, glucose homeostasis, and other metabolic traits in humans and livestock, functional investigations had not been performed. We generated Lcorl knockout mice (Lcorl-/-) and characterized the metabolic traits. We found that Lcorl-/- pups are born smaller than the wild-type (WT) littermates before reaching normal weight by 7 to 9 weeks of age. While aging, Lcorl-/- mice remain lean compared to WT mice, which is associated with a decrease in daily food intake. Glucose tolerance and insulin sensitivity are improved in Lcorl-/- mice. Mechanistically, this stunted growth is linked to a reduction of circulating levels of IGF-1. The expression of the genes downstream of GH signaling and the genes involved in glucose and lipid metabolism are altered in the liver of Lcorl-/- mice. Furthermore, Lcorl-/- mice are protected against a high-fat diet challenge and show reduced exercise capacity in an exercise stress test. Collectively, our results are congruent with many of the metabolic parameters linked to the Lcorl locus as reported in GWAS in humans and livestock.

Thyroid autoimmune diseases, such as Hashimoto thyroiditis and Graves disease, are significantly more prevalent in women than in men, suggesting underlying biological differences in immune system function and regulation between sexes. Plasma B cells are crucial in autoimmunity due to their role in producing antibodies targeting self-antigens, but their presence in the thyroids of women without clinical autoimmune diseases remains largely unexplored. This study investigates the infiltration of plasma B cells in female thyroids specifically excluding those with any clinical signs of autoimmune diseases. Using bulk RNA-seq analysis, we identified significant sex differences in gene expression profiles, particularly in genes associated with plasma B cells. Single-cell RNA-seq and spatial transcriptomic analyses further revealed that the CXCL13-CXCR5 signaling axis plays a pivotal role in recruiting and organizing plasma B cells within the thyroid tissue. These findings suggest that the inherent presence of plasma B cells in the female thyroid, driven by CXCL13, may contribute to the higher risk of developing autoimmune thyroid diseases in women. Our study provides new insights into the immune landscape of the thyroid and underscores the importance of understanding sex-specific differences in immune cell distribution and function.

Mammalian genomes contain thousands of genes for long noncoding RNA (lncRNAs), some of which have been shown to affect protein coding gene expression through diverse mechanisms. The lncRNA transcripts are longer than 200 nucleotides and are often capped, spliced, and polyadenylated, but not translated into protein. Nuclear lncRNAs can modify chromatin structure and transcription in trans or cis by interacting with the DNA, forming R-loops, and recruiting regulatory proteins. Not much is known about the role of lncRNA in pituitary gland differentiation and function. We mined transcriptome data from mouse pituitary glands collected at embryonic days 12.5 and 14.5 and identified over 200 different lncRNA transcripts. To develop a research resource for the study of lncRNA, we used pituitary cre transgenes to tag pituitary cell types in adult mice with fluorescent markers, and enriched for thyrotropes, gonadotropes, and somatotropes using fluorescence-activated cell sorting. We determined the transcriptome of each cell population using RNA sequencing and mined the data for lncRNA. We detected hundreds of lncRNAs in adult pituitary cells; a few were located immediately nearby genes that encode pituitary hormones or lineage-specific transcription factors. The location of these lncRNAs suggests the possibility of a cis-acting regulatory role in pituitary development or function, and we observe coordinated expression of 2 of them with their putative target genes in transgenic mice. This research resource sets the foundation for examining the actions of lncRNAs on their putative target genes and determining whether they have roles during development and in response to physiological demand.

Chronic stress results in long-term dynamic changes at multiple levels of the hypothalamic-pituitary-adrenal (HPA) axis resulting in stress axis dysregulation with long-term impacts on human and animal health. However, the underlying mechanisms and dynamics of altered of HPA axis function, in particular at the level of pituitary corticotrophs, during a period of chronic stress and in the weeks after its cessation (defined as "recovery") are very poorly understood. Here, we address the fundamental question of how a period of chronic stress results in altered anterior pituitary corticotroph function and whether this persists in recovery, as well as the transcriptomic changes underlying this. We demonstrate that, in mice, spontaneous and corticotrophin-releasing hormone-stimulated electrical excitability of corticotrophs, essential for ACTH secretion, is suppressed for weeks to months of recovery following a period of chronic stress. Surprisingly, there are only modest changes in the corticotroph transcriptome during the period of stress, but major alterations occur in recovery. Importantly, although transcriptional changes for a large proportion of mRNAs follow the time course suppression of corticotroph excitability, many other genes display highly dynamic transcriptional changes with distinct time courses throughout recovery. Taken together, this suggests that chronic stress results in complex dynamic transcriptional and functional changes in corticotroph physiology, which are highly dynamic for weeks following cessation of chronic stress. These insights provide a fundamental new framework to further understand underlying molecular mechanisms as well approaches to both diagnosis and treatment of stress-related dysfunction of the HPA axis.

Surfactants are molecules with both hydrophobic and hydrophilic structural groups that adsorb at the air-water or oil-water interface and serve to decrease the surface tension. Surfactants combine to form micelles that surround and break down or remove oils, making them ideal for detergents and cleaners. Two of the most important classes of nonionic surfactants are alkylphenol ethoxylates (APEOs) and alcohol ethoxylates (AEOs). APEOs and AEOs are high production-volume chemicals that are used for many industrial and residential purposes, including laundry detergents, hard-surface cleaners, paints, and pesticide adjuvants. Commensurate with better appreciation of the toxicity of APEOs and the base alkylphenols, use of AEOs has increased, and both sets of compounds are now ubiquitous environmental contaminants. We recently demonstrated that diverse APEOs and AEOs induce triglyceride accumulation and/or preadipocyte proliferation in vitro. Both sets of contaminants have also been demonstrated as obesogenic and metabolism-disrupting in a developmental exposure zebrafish model. While these metabolic health effects are consistent across models and species, the mechanisms underlying these effects are less clear. This study sought to evaluate causal mechanisms through reporter gene assays, relative binding affinity assays, coexposure experiments, and use of both human cell and zebrafish models. We report that antagonism of thyroid hormone receptor signaling appears to mediate at least a portion of the polyethoxylate-induced metabolic health effects. These results suggest further evaluation is needed, given the ubiquitous environmental presence of these thyroid-disrupting contaminants and reproducible effects in human cell models and vertebrate animals.

GnRH governs reproduction by regulating pituitary gonadotropins. Unlike most vertebrates, gnrh-/- zebrafish are fertile. To elucidate the role of the hypophysiotropic-Gnrh3 and other mechanisms regulating pituitary gonadotropes, we profiled the gene expression of all individual pituitary cells of wild-type and gnrh3-/- adult female zebrafish. The single-cell RNA sequencing showed that LH and FSH gonadotropes express the 2 gonadotropin beta subunits with a ratio of 140:1 (lhb:fshb) and 4:1 (fshb:lhb), respectively. Lh gonadotropes predominantly express genes encoding receptors for GnRH (gnrhr2), thyroid hormone, estrogen, and steroidogenic factor 1. No GnRH receptor transcript was enriched in FSH gonadotropes. Instead, cholecystokinin receptor-b and galanin receptor-1b transcripts were enriched in these cells. The loss of the Gnrh3 gene in gnrh3-/- zebrafish resulted in downregulation of fshb in LH gonadotropes and upregulation of pituitary hormones like TSH, GH, prolactin, and proopiomelanocortin-a. Likewise, targeted chemogenetic ablation of Gnrh3 neurons led to a decrease in the number of fshb+, lhb + and fshb+/lhb + cells. Our studies suggest that Gnrh3 directly acts on LH gonadotropes through Gnrhr2, but the outcome of this interaction is still unknown. Gnrh3 also regulates fshb expression in both gonadotropes, most likely via a non-GnRH receptor route. Altogether, while LH secretion and synthesis are likely regulated in a GnRH-independent manner, Gnrh3 seems to play a role in the cellular organization of the pituitary. Moreover, the coexpression of lhb and fshb in both gonadotropes provides a possible explanation as to why gnrh3-/- zebrafish are fertile.

Growth differentiation factor-15 (GDF15) increases in circulation during pregnancy and has been implicated in food intake, weight loss, complications of pregnancy, and metabolic illness. We used a Gdf15 knockout mouse model (Gdf15-/-) to assess the role of GDF15 in body weight regulation and food intake during pregnancy. We found that Gdf15-/- dams consumed a similar amount of food and gained comparable weight during the course of pregnancy compared with Gdf15+/+ dams. Insulin sensitivity on gestational day 16.5 was also similar between genotypes. In the postnatal period, litter size and survival rates were similar between genotypes. There was a modest reduction in birth weight of Gdf15-/- pups, but this difference was no longer evident from postnatal day 3.5 to 14.5. We observed no detectable differences in milk volume production or milk fat percentage. These data suggest that GDF15 is dispensable for changes in food intake, and body weight as well as insulin sensitivity during pregnancy in a mouse model.

Aging of the general population has led to a substantial increase in the prevalence of osteoporosis over the past decades. While there are effective pharmacological agents that increase bone formation, decrease bone resorption, and decrease fracture risk, they do not uniformly cure osteoporosis. This has prompted investigations to examine whether combination therapy (COMBO) with these agents can result in an additive benefit. Since concomitant therapy with denosumab and teriparatide has shown promise in this respect, investigations were undertaken to explore whether the changes in osteogenic phenotype could provide insight into the cellular and molecular mechanism of this effect. Investigations were performed in postmenopausal women receiving denosumab, teriparatide, or both for 3 months. Histomorphometric parameters were the primary outcome, while exploratory studies examined RNA expression in bone biopsies as well as in sorted and cultured bone marrow stromal cells (BMSCs). Osteogenic colony forming units of BMSCs were also evaluated. The studies demonstrated that COMBO results in an increase in osteoprogenitors, evidenced by an increase in osteoblastic colony-forming units. This was associated with an increased in BMSC expression of LGR6 (leucine-rich repeat containing G protein-coupled receptor 6), a stem cell marker and activator of the canonical Wnt signaling pathway. These data suggest that enhancement of canonical Wnt signaling contributes to the increase in osteoprogenitors and consequently an increase in bone density in postmenopausal women receiving COMBO for osteoporosis.

Prolactinomas, the most common pituitary-secreting adenomas, can be effectively treated with dopamine D2 receptor (D2R) agonists. However, a subset of them (∼20%) are resistant to dopamine-based therapies and require extirpation. The molecular mechanisms underlying their escape from dopaminergic regulation are not fully elucidated and may include alterations in D2R signaling. D2R can heteromerize with other G protein-coupled receptors, resulting in modulation of dopaminergic signaling. Because the bradykinin receptor type 2 (B2R) is overexpressed in prolactinomas, we interrogated whether this dopaminergic dysregulation observed in some prolactinomas may depend on a physical and functional interaction between D2R and B2R. The formation of B2R-D2R complexes in cultured cells transiently expressing both receptors was validated using NanoBiT technology. Interestingly, although D2R stimulation did not alter B2R-induced intracellular calcium mobilization, B2R stimulation abolished D2R signaling through modulation of cAMP. The existence of B2R-D2R complexes in pituitary adenomas biopsies was evaluated using an ALPHALisa approach. Importantly, B2R-D2R complexes were detected in human prolactinomas and nonfunctioning pituitary adenomas, but not in mixed (prolactin + growth hormone)-secreting adenomas. These results suggest that overexpression of B2R in resistant prolactinomas may promote the formation of B2R-D2R complexes, with B2R precluding D2R signaling, thus generating resistance to D2R agonists.

Thyroid hormones and their receptors (TRs) play critical roles during vertebrate development. One of the most dramatic developmental processes regulated by thyroid hormones is frog metamorphosis, which mimics the postembryonic (perinatal) period in mammals. Here, we review some of the findings on the developmental functions of thyroid hormones and TRs as well as their associated mechanisms of action obtained from this model system. More than 2 decades ago, a dual function model was proposed for TR in anuran development. During larval development, unliganded receptors recruit corepressors to repress thyroid hormone response genes to prevent premature metamorphic changes. Subsequently, when thyroid hormone levels rise, liganded receptors recruit coactivators to activate thyroid hormone response genes, leading to metamorphic changes. Over the years, molecular and genetic approaches have provided strong support for this model and have shown that it is applicable to mammalian development as well as to understanding the diverse effects of thyroid hormones in normal physiology and diseases caused by thyroid hormone signaling dysfunction.