Abstract Pancreatic β-cells integrate metabolic and electrical signals to couple nutrient sensing with insulin secretion, yet the physiological contribution of the neuronal K+Cl− cotransporter-2, Kcc2 (Slc12a5) to β-cell function and whole-body metabolic regulation remains incompletely understood. To define its role in vivo, we generated mice lacking Kcc2 selectively in insulin-secreting β-cells (Kcc2βKO) and evaluated growth, body composition, feeding behavior, glucose homeostasis and islet function from weaning through early adulthood. Kcc2βKO mice developed sex- and age-dependent metabolic phenotypes. Females exhibited lower body weight at weaning and increased lean mass during adulthood, whereas males displayed reduced body-weight gain despite increased food intake. Feeding microstructure analyses identified age-dependent alterations in meal patterning in male Kcc2βKO mice. Morphometric analysis demonstrated increased mean islet area without changes in endocrine cell composition, and isolated islets exhibited enhanced glucose-stimulated insulin secretion at younger ages. Male, but not female, Kcc2βKO mice showed improved glucose tolerance and age-dependent differences in glycemic responses to exogenous insulin, whereas both sexes exhibited attenuated glycemic responses to alanine challenge. Fasting blood glucose remained largely preserved across genotypes, although fasting plasma insulin concentrations varied according to sex, age and fasting duration. These findings identify β-cell Kcc2 as a physiological contributor to nutrient-stimulated insulin secretion and demonstrate that disruption of β-cell chloride homeostasis is accompanied by integrated, age- and sex-dependent adaptations in body-weight regulation, feeding behavior and glucose homeostasis.
Abstract N-acetyl-L-cysteine (NAC) is a widely used antioxidant with increasing public interest in its use for treating metabolic disease, yet its effects on pancreatic β cells remain incompletely understood. Most studies focus on NAC's benefits under pathological conditions—such as obesity, high-fat diet exposure, and type 2 diabetes—where oxidative stress impairs β-cell function, identity, and survival. In these contexts, NAC can reduce oxidative damage, preserve insulin secretion, and limit islet fibrosis. However, far fewer studies examine NAC under normal physiological or aging conditions, where moderate reactive oxygen species levels are required for β-cell signaling and glucose-stimulated insulin secretion. Emerging evidence shows that excessive antioxidant exposure during non-pathological states may disrupt redox-dependent pathways, suppress insulin biosynthesis and exocytosis, and contribute to reductive stress. Here, we review the current evidence of NAC's impact on β cells across physiological, aging, and pathological settings. Moreover, we highlight that NAC can be protective or detrimental depending on redox state, metabolic environment, and dosing, which emphasizes the need for careful consideration of antioxidant use in humans.
Abstract Differentiated Leydig cells (LCs) produce testosterone and INSL3, 2 hormones essential for male sex differentiation and fertility. In mice, the developmental origin of adult Leydig cells (ALCs) and the presence of stem Leydig cells (SLCs) in adulthood remain unresolved. To investigate this, we used the Leydig cell-specific Insl3iCre line combined with Rosa26lox-STOP-lox-iDTR/lox-STOP-lox-TdTomato to genetically ablate the committed LC lineage in adult mice. These mice displayed a normal phenotype without diphtheria toxin (DT). Following DT administration, TdTomato-positive and CYP17A1-positive LCs were eliminated within 4 to 7 days, leading to marked reductions in testosterone levels and androgen-dependent organ weights. Activated Caspase 3 confirmed apoptosis of targeted Leydig cells during the acute ablation phase. This was accompanied by transient macrophage recruitment as shown by F4-80 immunofluorescence, consistent with their involvement in clearing apoptotic Leydig cells. Importantly, COUP-TFII-positive/αSMA-negative/CYP17A1-negative/TdTomato-negative cells persisted adjacent to peritubular and perivascular myoid cells, identifying a candidate Insl3-negative precursor population. Newly emerging TdTomato-positive cells subsequently appeared predominantly around seminiferous tubules and, to a lesser extent, blood vessels, marking the onset of Leydig cell regeneration. Testosterone levels progressively recovered as these cells acquired CYP17A1 expression and populated the interstitial compartment. By 65 days post-DT, the ALC population and endocrine function were fully restored. These findings provide strong functional evidence for adult SLCs capable of repopulating the LC lineage after complete ablation and identify the peritubular compartment as a major regenerative niche. This inducible LC-depletion mouse model provides a powerful tool to investigate SLC biology and the mechanisms governing LC differentiation and testicular endocrine homeostasis.
Lineage plasticity is a major mechanism by which prostate cancer adapts to therapeutic pressure, particularly following sustained inhibition of androgen receptor signaling. A central mediator of this process is BRN2, a POU3F2 neural lineage transcription factor that is normally suppressed in AR-dependent luminal prostate epithelium but becomes aberrantly activated during progression to castration-resistant and neuroendocrine (NE) prostate cancer. This review examines how BRN2 connects developmental neurogenesis to therapy-induced tumor reprogramming. We integrate insights from neurodevelopment and direct lineage reprogramming to describe how BRN2 maintains stem-like and NE transcriptional states. Mechanistically, we discuss how AR suppression, cooperating oncogenic drivers, epigenetic remodeling, and post-translational modification activate BRN2 and reshape transcriptional networks involving SOX2, Wnt signaling, N-Myc, and EZH2. We also evaluate strategies to target BRN2 and its associated dependencies, including direct inhibition of BRN2 DNA binding and pharmacologic disruption of cooperating epigenetic complexes such as BRD4, EZH2, and LSD1, though EZH2 inhibition may paradoxically promote further NE differentiation. We additionally assess BRN2 as a potential circulating biomarker, detectable in extracellular vesicles, though no clinical-grade assay has been validated. This review highlights BRN2 as a key transcriptional regulator of lineage plasticity in prostate cancer, with important implications for overcoming therapy resistance in advanced prostate cancer.
Intestinal epithelial differentiation is tightly regulated to maintain tissue homeostasis and systemic metabolic function. Although the intrinsic transcriptional programs governing enteroendocrine cell (EEC) development have been characterized extensively, the role of extrinsic immune signals in directing lineage specification is not completely understood. In particular, how cytokine signaling influences differentiation of EEC subtypes remains unclear. Here, we investigated the role of interleukin-22 (IL-22) in EEC differentiation using human induced pluripotent stem cell-derived intestinal organoids and in vivo models. IL-22 selectively increased proglucagon (GCG) expression and the number of glucagon-like peptide-1 (GLP-1)-positive EECs without affecting other EEC markers. This effect was associated with enhanced expression of the lineage-related transcription factors neurogenin 3 and forkhead box A2. Pharmacological inhibition of signal transducer and activator of transcription 3 (STAT3) signaling attenuated the IL-22-induced increases in GCG expression and GLP-1-positive cell abundance, indicating a role of STAT3 in mediating these effects. Mechanistically, relatively high expression of IL-22 receptor subunit alpha 1 in undifferentiated epithelial cells was associated with STAT3 activation induced by IL-22. Consistent with these findings, in vivo IL-22 administration increased intestinal GCG expression and GLP-1 levels in the circulation and intestinal tissue. Importantly, our findings indicate that IL-22 does not globally promote EEC differentiation but rather selectively directs epithelial lineage commitment toward the GCG-positive EEC fate. These results suggest that IL-22/STAT3 signaling induces human intestinal epithelial differentiation into GCG-positive EECs and may represent a strategy for modulating epithelial cell fate to influence systemic metabolic homeostasis.
