1,25-dihydroxyvitamin D3 [1,25(OH)2D3], parathyroid hormone (PTH), and fibroblast growth factor 23 (FGF23) are endocrine regulators of calcium homeostasis. To assess the contribution of 1,25(OH)2D3-mediated renal calcium reabsorption to systemic calcium balance and bone homeostasis, we generated mice with a targeted deletion of the vitamin D receptor (VDR) in renal tubules (VdrRen- mice), weaned them onto diets containing 1% or 0.2% calcium and examined their phenotype at 8 weeks of age. Despite higher urinary calcium excretion, VdrRen- mice maintained normocalcemia, suggesting compensatory adaptations in the intestine and bone. Transcript levels of intestinal calcium transporters were higher in male VdrRen- mice, particularly under dietary calcium restriction, whereas genotype-dependent changes were minimal in females. Bone mass was lower in VdrRen- mice of both sexes than in diet-matched wildtype littermates. On the 1% calcium diet, changes in calcium absorption and bone remodeling occurred without alterations in serum PTH and 1,25(OH)2D3, while FGF23 was elevated. Calcium restriction increased circulating PTH, 1,25(OH)2D3, and FGF23, with additional genotype- and sex-dependent effects on 1,25(OH)2D3 and FGF23. Together, these findings demonstrate that renal VDR signaling contributes to serum calcium conservation, and its loss triggers sexually dimorphic compensatory mechanisms in intestinal calcium absorption, especially under conditions of dietary calcium restriction.

Controlled ovarian hyperstimulation (COH) is essential in assisted reproductive technologies, although some studies have associated it with reduced reproductive success. We recently demonstrated that COH increases circulating ghrelin; however, its role in COH-induced alterations and the potential therapeutic impact of its inhibition remain unclear. Using a murine model, this study evaluated the effects of COH on preimplantation embryo development and implantation and examined whether the COH-induced alterations in these parameters are associated with hyperghrelinemia. Here, we evaluated hormonal profiles, gamete and embryo quality, implantation, and decidual characteristics in female mice, either in natural estrous cycles (controls) or following hyperstimulation, with or without treatment with ghrelin receptor antagonists [(D-Lys3)-GHRP-6 or PF-5190457].We found that COH increased ovulation rate, plasma progesterone and ghrelin levels compared with controls, without altering oocyte quality or early estradiol concentrations; although estradiol rose later (gestational day -GD- 7.5). COH also induced a delay in embryo development (in GD 3.5), which was reversed by the administration of (D-Lys3)-GHRP-6 or PF-5190457. COH showed a non-significant trend toward lower implantation, unrelated to hyperghrelinemia. COH did not affect decidual histology, embryotropic or embryotoxic factors, or uterine leukocyte infiltration; however, it reduced uterine IL-6 expression, which was restored by ghrelin receptor blockade, suggesting a mechanism for the delayed embryo development. Thus, COH-induced hyperghrelinemia negatively affects embryo development, potentially altering the uterine immune microenvironment.

The development of type 2 diabetes mellitus is closely associated with mitochondrial dysfunction of pancreatic β-cells, but the mechanisms by which glucagon-like peptide-1 receptor activation preserves mitochondrial homeostasis under glucotoxic conditions remain incompletely understood. Herein, we investigated whether Exendin-4 protects β-cells against chronic high glucose (HG)-induced mitochondrial injury by regulating the cAMP/PKA/Drp1 signaling pathway. INS-1 β-cells, pancreatic tissues from db/db mice, and isolated primary islets were used to assess oxidative stress, apoptosis, mitochondrial function and morphology, insulin secretion, and cAMP/PKA/Drp1 signaling. Prolonged HG exposure increased oxidative stress and apoptosis, impaired mitochondrial membrane potential, elevated mitochondrial ROS accumulation, reduced ATP content, and promoted mitochondrial fragmentation in INS-1 β-cells. These changes were accompanied by increased Drp1 expression, reduced cAMP levels and PKA activity, decreased inhibitory phosphorylation of Drp1 at Ser637, and increased Ser616 phosphorylation. Exendin-4 attenuated HG-induced oxidative stress and apoptosis, restored mitochondrial function, improved mitochondrial morphology, and partially restored Drp1 Ser637 phosphorylation, whereas it did not significantly affect HG-induced Ser616 phosphorylation. In db/db mice, Exendin-4 improved metabolic parameters and alleviated β-cell apoptosis, with partial recovery of Drp1 Ser637 phosphorylation in pancreatic islets. Furthermore, glucose-stimulated insulin secretion assays in isolated primary islets showed that Exendin-4 improved β-cell secretory function in islets isolated from db/db mice. Pharmacological inhibition of PKA with H89 attenuated Exendin-4-induced Drp1 Ser637 phosphorylation and mitochondrial protection. Collectively, these results suggest that Exendin-4 protects pancreatic β-cells against HG-induced mitochondrial dysfunction and β-cell injury by restoring PKA-associated inhibitory phosphorylation of Drp1 at Ser637 and improving mitochondrial dynamics.

Prediabetes and Type 2 Diabetes represent major global health challenges and have escalated to pandemic levels. Adipose tissue functions as a critical endocrine organ, playing a central role in maintaining glucose homeostasis during fasting, feeding, and stress responses. In this study, we demonstrated that prolonged chronic hyperinsulinemic stress increases the burden of senescent adipocytes, accompanied by activation of the cGAS-STING signalling pathway. Chronic hyperinsulinemia-induced insulin-resistant 3T3-L1 and human mesenchymal stem cell-derived adipocytes exhibited elevated senescence-associated phenotypes, mitochondrial dysfunction and impaired cellular energetics. Notably, we found that mitochondrial DNA leakage triggered the cGAS-STING pathway in insulin-resistant adipocytes and mouse models. Temporal analysis revealed that mitochondrial dysfunction was detectable at earlier stages of chronic insulin exposure, preceding activation of the cGAS-STING pathway and senescence-associated markers, supporting a progressive model of cellular dysfunction. This phenomenon was also observed in adipose depots of individuals with Type 2 diabetes, underscoring the translational relevance of our findings. Targeting cGAS or STING, either pharmacologically or through genetic silencing, significantly reduced inflammatory and senescence-related features in hyperinsulinemia-induced insulin-resistant 3T3-L1 adipocytes. Furthermore, attenuation of senescence treatment with the combination of Dasatinib and Quercetin alleviated mitochondrial stress and associated adipose dysfunction. Collectively, our findings support a model in which prolonged hyperinsulinemic stress induces early mitochondrial dysfunction, followed by activation of cGAS-STING signalling and the subsequent emergence of adipocyte senescence-associated phenotypes, contributing to adipose tissue dysfunction in insulin resistance and Type 2 Diabetes.

Cardiac mitochondrial dysfunction is a crucial mechanism underlying obesity-induced cardiovascular diseases. A close link between obesity and gut microbiota has been revealed, and the benefits of gut microbiota modulation by probiotics have been widely identified. Although the probiotic Lactobacillus reuteri KUB-AC5 exerted anti-inflammatory activity and enhanced the activity of beneficial microbes, the effects of this probiotic on mitochondria in the obese heart have never been investigated. Male Wistar rats were divided into four groups to receive either a normal diet (ND; n = 9) or a high-fat and high-calorie diet (HFCD; n = 30) for 24 weeks. At the beginning of week 13, ND-fed rats received vehicle, while HFCD-fed rats were further subdivided into three groups (n = 10/group) to receive either vehicle, a live probiotic Lactobacillus reuteri KUB-AC5, or a heat-killed probiotic Lactobacillus reuteri KUB-AC5. At the end of week 24, cardiac functions were evaluated. The rats were then euthanized to enable blood and cardiac ventricle collection. Evidence from the obese rats treated with Lactobacillus reuteri KUB-AC5 in both forms indicated reduced body weight and attenuated insulin resistance. Regarding the heart, obese rats treated with either form of Lactobacillus reuteri KUB-AC5 had improved cardiac functions, mitochondrial dynamics, mitochondrial biogenesis, fat and ketone body utilization, anaplerosis, ATP production, and oxidative phosphorylation. In addition, treatment with this probiotic diminished oxidative stress and restored the antioxidative capacity of cardiac mitochondria. Our preclinical findings in male rats highlighted the benefits of the probiotic Lactobacillus reuteri KUB-AC5, given in both live and heat-killed forms, in alleviating obesity-induced cardiac mitochondrial dysfunction.

Astrocytes play an essential role in the control of gonadotropin-releasing hormone (GnRH) neurons. However, limited information is available in non-conventional animal models. This study aimed to explore the hypothalamic astrocyte distribution in the plains vizcacha (Lagostomus maximus), a South American hystricomorph rodent with distinctive reproductive physiology, and to analyze their spatial relationship with GnRH neurons throughout the life cycle. Female plains vizcachas were evaluated during non-pregnancy (ovulating and non-ovulating) and pregnancy (early-, mid-, and late-pregnant). Plasma levels of estradiol (E2), progesterone (P4), and luteinizing hormone (LH) were determined. Astrocytes were assessed by glial fibrillary acidic protein (GFAP) immunohistochemistry in hypothalamic regions involved in reproductive control, including the medial preoptic area (mPOA), arcuate nucleus (ARC), and median eminence (ME). Their spatial relationship with GnRH-immunoreactive neurons and fibers was also analyzed. Pregnancy was associated with marked hormonal changes, including significantly elevated E2 levels and dynamic variations in P4 and LH (P < 0.01). Astrocyte distribution was largely conserved across life stages in the mPOA and ME, whereas a significant reduction in GFAP-immunoreactive area was detected in the ARC during early pregnancy. Close appositions between astrocytic processes and GnRH neurons were observed in ovulating non-pregnant and pseudo-ovulating mid-pregnant animals. In the ME, very intimate contacts between astrocytic processes and GnRH fibers in the palisade layer were detected exclusively during pregnancy. In conclusion, these findings reveal a steroid-dependent plasticity of hypothalamic astrocytes and support a key role for astrocyte-GnRH neuron interactions in the regulation of reproductive neuroendocrine function during gestation in the plains vizcacha.

Postmenopausal osteoporosis, characterized by estrogen deficiency-induced bone loss and elevated fracture risk, is commonly managed with hormone replacement therapy (HRT). This study aimed to evaluate whether passive exercise via whole-body vibration training (WBVT) could serve as an effective alternative to HRT (represented by 17β-estradiol (E2) supplementation) for improving bone microarchitecture and metabolism and to investigate whether combining WBVT with E2 supplementation yields superior bone-protective effects compared to E2 supplementation alone. To this end, mice underwent ovariectomy (OVX) or sham surgery. After a 4-week recovery, OVX mice received E2 supplementation, WBVT, combined treatment (E2 + WBVT), or no treatment for 10 weeks. Assessments included serum E2 levels, femur weight, femoral microarchitecture, tibial biomechanical properties, and the expression of osteogenic and osteoclastic factors. Compared to sham-operated mice, OVX mice exhibited lower serum E2 and femur weight, degenerative bone microarchitecture, impaired biomechanical performance, decreased osteogenic factors, and elevated osteoclastic factors - all notably reversed by E2 supplementation. The 10-week WBVT regimen partially improved bone microarchitecture, biomechanical performance, and homeostasis but was less effective than E2 supplementation. Moreover, the combination of E2 supplementation and WBVT did not demonstrate further improvements in these bone parameters relative to E2 supplementation monotherapy. In conclusion, the 10-week WBVT regimen did not produce bone improvements comparable to E2 supplementation in OVX mice, and the combined treatment did not enhance efficacy beyond that of E2 supplementation alone.

Liver fibrosis (LF) is a progressive chronic liver disease characterized by excessive accumulation of extracellular matrix, which is primarily driven by the abnormal activation of hepatic stellate cells (HSCs). Gamma-aminobutyric acid (GABA) receptors have been reported to inhibit HSC activation, while solute carrier family 32 member 1 (SLC32A1), a GABA transporter protein, is speculated to be involved in LF regulation, although its specific role and underlying molecular mechanisms remain unclear. Therefore, this study aimed to investigate the role of SLC32A1 in HSC activation and LF progression, as well as to elucidate its downstream regulatory mechanisms. Our results showed that SLC32A1 levels were elevated in LF patients. In vivo experiments demonstrated that SLC32A1 knockout alleviated CCl4-induced LF in mice. In vitro studies revealed that SLC32A1 was specifically upregulated in TGF-β1-stimulated LX-2 cells (HSCs), but not in THLE-2, THP-1, or LSECs. SLC32A1 overexpression exacerbated LX-2 activation and fibrosis, while its knockdown reversed TGF-β1-induced effects. Mechanistically, SLC32A1 promoted GABA and glycine exocytosis in LX-2 cells. However, neither exogenous nor endogenous GABA/glycine affected the reduced activation mediated by SLC32A1 knockdown, prompting investigation into alternative pathways. Among 55 differentially expressed genes, PAI-1 showed the largest difference. Critically, PAI-1 overexpression reversed the decrease in activation and fibrosis induced by SLC32A1 knockdown. Collectively, these findings demonstrate that downregulation of the SLC32A1-mediated PAI-1 pathway, rather than the GABA pathway, attenuates HSC activation and LF, highlighting SLC32A1 as a potential novel therapeutic target for LF.

We previously reported that triiodothyronine (T3) promotes maturation of dendritic cells (DCs) and enhances their ability to induce pro-inflammatory and cytotoxic T-cell responses through Akt signaling. However, the underlying mechanisms remain incompletely understood. Sphingosine-1-phosphate (S1P), a bioactive sphingolipid, is implicated under several pro-inflammatory conditions. Here, we investigated the role of sphingosine kinase 1 (SK1), S1P, and its receptors (S1PRs) in the immunomodulatory effects of T3 on DCs and the ensuing adaptive immune response. DCs were generated from the bone marrow of C57BL/6 wild-type or SK1 knockout mice and stimulated with T3 (T3-DC). To modulate the S1P pathway, PF-543 (SK1 inhibitor), S1P, or FTY720 (S1PR functional antagonist) was added prior to T3. Phosphorylated Akt (p-Akt) and phosphorylated STAT3 (p-STAT3) were analyzed by Western blotting. Splenocytes from BALB/c mice were co-cultured with DCs under SK1 or S1PR inhibition and exposed to T3. Cell markers and proliferation were evaluated by flow cytometry, and cytokines were measured by flow cytometry and ELISA. We show that the SK1/S1P/S1PR pathway regulates IL-12p70 production in T3-DC, while S1PRs also modulate IL-6 secretion. Mechanistically, S1P signaling mediates T3-induced Akt phosphorylation in DCs. STAT3 activation was observed in T3-DC and was not altered by inhibition of SK1 or S1PR. Although the SK1/S1P/S1PR axis did not alter T cell proliferation, S1PR inhibition increased IFN-γ, and inhibition of either SK1 or S1PRs enhanced IL-17 secretion by splenocytes. Altogether, these findings suggest that a complex sphingolipid-mediated signaling network modulates the immunostimulatory effects of T3 on DCs and the driven adaptive immunity.

The main objective of this study is to evaluate the impact of therapeutic regimens and visceral fat dynamics on complete remission rates in fertility-preserving management of atypical endometrial hyperplasia (AEH) and early endometrial cancer (EC) and to identify modifiable predictors of treatment efficacy. This interim analysis is based on data from an ongoing, prospective, open-label randomized controlled trial (Chinese Clinical Trial Registry ChiCTR2200067099). Conducted in accordance with the pre-specified study protocol, the analysis included the first 73 enrolled participants, who were randomized to either GnRH-a combined with daily letrozole or high-dose oral progestins (medroxyprogesterone acetate or megestrol acetate). All patients received standardized lifestyle interventions (diet and exercise). The exploratory aim was to assess the association between early changes in body composition - measured using the InBody 770 analyzer over 12 weeks - and treatment response. Multivariate logistic regression analyses were performed to assess the association between treatment outcomes and changes in weight and body fat distribution. In this interim analysis, 73 patients were enrolled, including 31 patients with AEH (42.5%) and 42 patients with EC (57.5%). After 12 weeks of treatment, 40 patients achieved CR, while 33 cases did not. After implementing positive education and lifestyle interventions, patients experienced reductions in weight and indicators of body fat distribution after 12 weeks of treatment. The gonadotropin-releasing hormone agonist plus aromatase inhibitors (GnRH-a + AIs) group showed a significantly higher complete response rate than the megestrol acetate/medroxyprogesterone acetate (MA/MPA) group (75.6 vs 28.1%; risk difference: 0.48, 95% CI: 0.27-0.68). After adjustment for covariates, each 1 cm increase in baseline hip circumference was associated with 7.187-fold higher odds of complete response rate (OR = 7.19, 95% CI: 1.03-50.41, P = 0.047). Conversely, progestin therapy (vs GnRH-a + AIs) was associated with 92.7% lower odds of CR rate (OR = 0.07, 95% CI: 0.02-0.35, P = 0.001). Furthermore, a reduction in visceral fat area (per 1 cm2 decrease) was associated with 35.9% higher odds of complete response (OR = 1.36, 95% CI: 1.02-1.81, P = 0.034). Conversely, progestin therapy (vs GnRH-a + AIs) was associated with 89.2% lower odds of CR rate (OR = 0.108, 95% CI: 0.015-0.773, P = 0.027). We found that treatment regimen selection critically influences therapeutic outcomes in fertility-sparing management. Our study shows that reducing visceral fat area substantially improves treatment efficacy, making it a key indicator for predicting treatment effects. This study is part of a registered clinical trial (Chinese Clinical Trial Registry ID: ChiCTR2200067099; registered December 27, 2022).

Membrane-initiated estrogen receptor-α (mERα) signaling has been demonstrated to be crucial for normal bone metabolism, and our previous work has confirmed its essential role in osteoblasts. However, the contribution of brain-derived mERα signaling to bone homeostasis remains unexplored. To investigate the role of brain-derived mERα signaling in bone metabolism, we developed a POMC-C451Af/f mouse model in which mERα signaling is selectively inactivated in POMC-expressing neurons. Gonadal-intact female POMC-C451Af/f mice exhibited disturbed sex steroid levels and significantly increased bone mass in both cortical and trabecular compartments compared to littermate C451Af/f controls after sexual maturation (16 weeks old). In ovariectomized female POMC-C451Af/f mice, estradiol (E2) treatment enhanced the anabolic response in trabecular bone of the femur compared to controls, while the estrogen response in cortical bone was similar between the genotypes. Gonadal-intact male POMC-C451Af/f mice displayed altered levels of testosterone compared to controls at 24 weeks of age. In orchiectomized male mice, responses to E2 treatment were similar across all examined parameters between POMC-C451Af/f and control mice. In conclusion, our findings reveal an important role of membrane-initiated ERα signaling in POMC neurons in regulating hormone balance and bone metabolism, with more pronounced effects in female mice.

Glucocorticoid excess induces a plethora of metabolic disturbances, including obesity, muscle atrophy, hepatic steatosis and increased energy expenditure, which are hallmark features of Cushing's syndrome. Despite the understanding of these outcomes, it remains unclear how glucocorticoid excess affects the metabolically critical nicotinamide adenine dinucleotide (NAD+) and related metabolites and transcripts, including redox cofactors, intermediates and biosynthetic enzymes. Furthermore, the therapeutic potential of NAD+ precursor supplementation in this context is unknown. Here, we investigated tissue- and sex-specific effects of sustained corticosterone treatment on NAD+ and its related metabolites and transcripts in skeletal muscle and liver of male and female mice and assessed the efficacy of nicotinamide riboside (NR) supplementation in preventing glucocorticoid-induced metabolic dysfunction. Using LC-MS and gene expression analyses, we demonstrate that glucocorticoid excess increases NAD+ and NAAD levels in skeletal muscle, alongside modest changes in salvage pathway gene expression in males and females. However, NADP+ was increased in males only. In the liver, glucocorticoid treatment decreased NADPH and increased the NADP+/NADPH ratio in males and females, with widespread downregulation of biosynthetic enzymes despite stable NAD+ levels. NR supplementation failed to prevent classical features of glucocorticoid excess, including increased body weight, muscle atrophy, adiposity, hepatic triglyceride accumulation and elevated energy expenditure. These findings not only reveal novel effects of glucocorticoid excess on NAD+ and related metabolites and transcripts but also question the importance of NAD+ in glucocorticoid-induced metabolic dysfunction. Consequently, whilst NAD+ pathways are impacted by glucocorticoid excess, our data show no therapeutic benefit of NR supplementation under the conditions tested and do not support its efficacy in this model of glucocorticoid excess.

Modern neuroimaging advances in methodology and data modelling allow for brain tissue structure and function to be imaged in increasing detail and specificity. These advances have promise when applied to polycystic ovary syndrome (PCOS), a common multisystem condition associated with psycho-cognitive symptomatology and an increased risk of cerebrovascular disease. This hot-topic review will outline three biological themes that encompass PCOS neurobiology and symptomatology and may benefit from the application of advanced neuroimaging techniques: i) the endocrine system and biorhythms, ii) the cerebrovascular system, and iii) neural structure and function. How modern neuroimaging advances can provide new insights to these areas will be discussed. While knowledge of brain health in PCOS is still an emerging field, advanced neuroimaging offers valuable opportunities to investigate the origins and enduring consequences of PCOS.

Polycystic ovary syndrome (PCOS) is a common disorder among women of reproductive age, characterized mainly by metabolic and endocrine disturbances caused by interactions of genetic, environmental, and other factors. Bile acid metabolism, as a key link between gut microbiota and the host, has been increasingly associated with the onset and development of PCOS. However, no systematic summary of this relationship is available so far. This review first discusses potential factors leading to bile acid pool changes in PCOS patients, including sex hormones, diet, and certain bacterial genera, which may promote PCOS by regulating bile acid metabolism. Bile acid signaling critically regulates host glucose and lipid homeostasis, follicular development, and sex hormone synthesis in a tissue-specific manner, indicating the limitations of focusing only on a single organ or cell type. Clinical studies show that bile acid metabolic profiles can distinguish PCOS patients from healthy controls, although the profiles are not fully consistent. Their heterogeneity is related to metabolic phenotypes, suggesting that bile acid profiling may help subtype PCOS. Given its role in insulin resistance, ovarian function, and steroid hormone synthesis, bile acid metabolism may act as a core hub in PCOS pathogenesis. Further mechanistic research is needed to better understand these processes and support the development of precise diagnostics and targeted therapies for PCOS.

Prediabetes, a condition defined by the World Health Organization (WHO), has become a significant global health issue affecting a substantial portion of the world's population. This study aims to investigate the levels of adipocyte fatty acid-binding protein-4 (a-FABP or FABP-4), a biomarker found in individuals with prediabetes. FABP-4 is a protein released by both adipocytes and macrophages and plays a crucial role in influencing insulin resistance and lipid metabolism. The focus of this study is to evaluate FABP-4 levels in individuals with prediabetes and its correlation with metabolic parameters and CRP levels. The study was conducted on 90 participants, including individuals diagnosed with prediabetes (n = 44) and a healthy control (n = 44) group. The findings reveal that FABP-4 levels are significantly elevated in individuals with prediabetes. Furthermore, positive correlations were observed between FABP-4 levels and fasting and postprandial blood glucose, HbA1c, and C-reactive protein (CRP). Regression analysis indicates that FABP-4 is independently associated with prediabetes and, when considered alongside the triglyceride-to-high-density lipoprotein (HDL) ratio, is associated with prediabetes. This study underscores the association between FABP-4 and prediabetes, highlighting its potential role in fundamental processes such as insulin resistance, lipolysis, and inflammation. Additionally, it suggests that the triglyceride/HDL ratio is significantly associated with prediabetes. In conclusion, FABP-4 and the triglyceride/HDL ratio have the potential to be utilized as biomarkers in the assessment of prediabetes, contributing to the development of new treatment targets in this context.