Endocrinology最新文献

Serotonin neurons are thought to exert a modulatory influence on the secretion of the gonadotropin hormones in mammals, but their mechanism of action remains unclear. We examined here the potential role of serotonin neurons in modulating the activity of the gonadotropin-releasing hormone (GnRH) pulse generator formed by the arcuate nucleus kisspeptin (ARNKISS) neurons. Acute brain slice electrophysiology revealed that ∼60% of ARNKISS neurons in diestrous female mice were activated by serotonin while less than 10% were inhibited. Pharmacological studies indicated that combinatorial patterns of 5-HT receptor subtype activation were likely responsible for the excitatory actions. The role of serotonin in ARNKISS neuron synchronization behavior was assessed using GCaMP imaging in acute brain slices from diestrous female and male mice. In both sexes, serotonin-evoked potent recurring bouts of synchronization activity amongst ARNKISS neurons. To evaluate the impact of serotonin in vivo, we used "fluidic" GCaMP fiber photometry in which serotonin was infused directly into the ARN while recording the ARNKISS neuron population activity in freely behaving diestrous female mice. In all cases, the infusion of serotonin evoked a robust ARNKISS neuron synchronization episode. These data demonstrate that serotonin exerts a direct, predominantly stimulatory action on ARNKISS neuron pulse generator through a variety of 5-HT receptors. Serotonergic inputs appear to provide a potent synchronizing influence on the ARNKISS neuron population and suggest considerable potential for 5-HT to control the frequency of pulsatile reproductive hormone secretion in mice and likely other mammals.

Uterine leiomyomas persist and grow within a chronically pro-oxidant environment despite reduced antioxidant capacity, suggesting the existence of adaptive stress-tolerance mechanisms. Although estrogen and progesterone are well-established regulators of leiomyoma growth, their roles in coordinating mitochondrial function under oxidative stress remain poorly defined. Here, we investigated how estrogen and progesterone receptor signaling modulate oxidative stress-induced transcriptional programs and mitochondrial metabolic responses in uterine leiomyoma cells. Primary patient-derived leiomyoma spheroids were exposed to paraquat-induced oxidative stress in the presence of estradiol, progestins, or hormone receptor antagonists. Transcriptomic responses were assessed by RNA sequencing with differential expression and gene set enrichment analyses, while mitochondrial function was evaluated using Seahorse extracellular flux assays alongside measurements of senescence and cell viability. Estrogen and progesterone signaling reshaped oxidative stress-responsive gene expression programs linked to senescence, apoptosis, and mitochondrial regulation, which was evident with hormone receptor antagonism. Functional metabolic analyses revealed that hormonal signaling preserved mitochondrial maximal respiration and spare respiratory capacity under oxidative stress, while hormone blockade selectively impaired mitochondrial reserve capacity without compensatory glycolytic upregulation. Isoform-specific progesterone receptor effects further supported a role for differential receptor signaling in regulating mitochondrial adaptability. Together, these findings identify estrogen and progesterone receptor signaling as key regulators of mitochondrial stress tolerance in leiomyoma cells and support a model in which endocrine control of mitochondrial function enables cellular survival under sustained oxidative stress.

Mutations in the follicle-stimulating hormone receptor (FSHR) may result in impaired plasma membrane expression due to misfolding and intracellular retention of the receptor, leading to disease. Rescue of misfolded receptors may be achieved employing pharmacological chaperones (small molecules that specifically bind misfolded proteins, promoting their correct trafficking to their site of action). This study analyzed whether the small-molecule FSHR agonist CAN1405 rescued membrane expression and function of 13 mutant FSHRs leading to premature ovarian failure in women. FSHRs were expressed in HEK-293 cells, and membrane expression was assessed by immunoblotting before and after incubation with CAN1405. Three trafficking defective variants in the ectodomain of the FSHR (A189V, N191I, and D224V) and 3 others located in transmembrane domains (TMD) 3 and 4, and extracellular loop 2 (A462P, P504S, and P519T, respectively) failed to respond (or did it marginally) to CAN1405 by increasing their membrane expression. In contrast, in 7 variants located in the TMD2 (D408Y, A419T, and I423T), TMD6 (A575V, P587H, and F591S), and extracellular loop 3 (L597I), CAN1405 rescued membrane expression of the variants. Functional studies showed that after CAN1405 removal, rescued FSHRs responded to the orthosteric agonist in terms of cAMP-mediated signaling and ERK1/2 phosphorylation. Refined molecular dynamics simulations using the cryo-EM structure of the FSHR revealed key conformational changes and interactions within the TMDs provoked by CAN1405, highlighting potential allosteric binding sites critical for receptor activation. These findings offer a promising therapeutic strategy for treating mutation-provoked FSHR dysfunction and underscore the synergistic potential of computational biophysics in drug discovery.

Missense mutations in nuclear receptor (NR) transcription factors cause a number of genetic disorders, including PPARG mutations that result in familial partial lipodystrophy type 3 (FPLD3). Experimental assessment is essential to establish a newly identified mutation as disease-causing, as accurately predicting the effect of a new mutation in silico remains challenging due to the multifunctional and modular nature of these proteins. However, deep structure-function characterization often requires specialized and technically demanding approaches, which may not be readily available. Therefore, we established a simple and robust experimental framework based on 4 complementary reporter assays that independently assess (1) ability of the full-length receptor to activate transcription; (2) integrity of the ligand-binding domain; (3) heterodimerization potential; and (4) DNA-binding capacity. As a proof of concept, we analyzed 3 uncharacterized FPLD3-associated loss-of-function variants and 2 bladder cancer-associated gain-of-function variants. Together, the 4 complementary assays showed unique functional phenotypes for all 5 mutants that were further supported by coregulator profiling. We therefore conclude that this framework provides a simple and robust first-line approach to identify functional alterations in peroxisome proliferator-activated receptor γ mutants with mechanistic resolution. This framework is broadly applicable across NRs and offers a scalable path to systematic variant interpretation both in research and clinical contexts.

During cancer metastasis, tumor cells survive in circulation by acquiring resistance to anoikis. Restoring vulnerability of cancer cells to anoikis can impair metastatic colonization, minimize treatment resistance, and tumor recurrence in patients. A compelling body of evidence has identified strategies for the development of effective inhibitors that can block survival pathways such as FAK, PI3K/AKT, MAPK and integrin signaling to prevent prostate cancer cells from leaving the primary tumor/site and/or to impair their colonization at secondary sites. Transcriptomic profiling recently identified anoikis-centered genes, including CDKN1A, NEDD9, CFL1, and JAM2, that may have potential prognostic value in prostate cancer progression and may also contribute to the emergence of therapeutic resistance to antiandrogens and taxane chemotherapy. Direct cytoskeletal remodeling by cofilin, a transforming growth factor-β (TGF-β) effector is linked to phenotypic plasticity changes. NEDD9 causes cytoskeletal dynamics through signaling pathways and it is correlated with tumor aggressiveness. CDKN1A affects cell cycle regulation, and JAM2 influences cell adhesion. This review interrogates the current evidence in the literature on the cellular drivers of anoikis resistance, intersecting with phenotypic plasticity in the prostate tumor microenvironment, toward determination of the underlying molecular mechanisms that can be exploited at the translational level for therapeutic applications. The identification and subsequent validation of novel anoikis-resistance based signatures can be of potential value as predictive markers of therapy resistance and tumor recurrence in patients with advanced prostate cancer.

Activin-class ligands of the transforming growth factor β family induce follicle-stimulating hormone (FSH) production by pituitary gonadotrope cells in mice via the actions of the transcription factors SMAD3, SMAD4, and FOXL2, which bind to cis-elements in the FSHβ subunit (Fshb) promoter. An enhancer region for murine Fshb transcription was identified in vitro. However, deletion of the region using CRISPR-Cas9 did not affect FSH synthesis or secretion in mice. Using single-nucleus ATAC-seq of whole murine pituitaries, we identified 3 additional open chromatin regions upstream of Fshb exclusively in gonadotropes. These regions, as well as the Fshb gene, were fully or partially closed in gonadotropes of FSH-deficient mice with genetically or pharmacologically inactivated activin type II receptors. The initially characterized enhancer region did not significantly alter basal or activin-stimulated murine Fshb promoter-reporter activity in homologous LβT2 cells. In contrast, the other 3 open chromatin regions enhanced basal and activin A-stimulated Fshb promoter-reporter activity in LβT2 cells, with the 2 most distal showing the greatest effects. These 2 regions were open, exhibited enrichment of the enhancer mark H3K27ac, and were bound by SMAD2/3 and FOXL2 in response to activin A in LβT2 cells. The most distal enhancer exhibited strong FOXL2 and weak SMAD4 binding in gel shift assays. SMAD4, but not FOXL2, directly bound the other distal enhancer. Mutation of defined FOXL2 and SMAD4 cis-elements diminished enhancer activity in reporter assays in LβT2 cells. Collectively, the data indicate that there may be as many as 4 activin-sensitive enhancers upstream of murine Fshb.

Cancers of the breast and prostate are one of the leading causes of cancer deaths in women and men, respectively. Although several treatment options have been developed to transform these cancers into manageable chronic diseases, they still contribute to over 70 000 deaths each year in the United States. Though majority of these cancers belong to slow growing differentiated subtypes, the cancers evolve over time due to treatment-related pressure into aggressive treatment-resistant types. A mechanism attributed to the transformation of hormonal and other cancers into aggressive treatment-refractory cancers is "lineage plasticity," a term used to describe a switch in the cell type or lineage. Evolving evidences suggest that the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway plays a key role in driving lineage plasticity. This review discusses the role of JAK-STAT signaling pathway in hormonal cancers' evolution into aggressive cancers and in treatment resistance, with focus on treatment-induced lineage plasticity.