Journal of molecular endocrinology最新文献

While pregnancy is known to be an inflammatory condition, preeclampsia (PE) is a more extreme state associated with higher cytokines and/or altered growth factors. It is generally assumed these PE-elevated factors come from stimulation of immune cells and/or hypoxic uterine tissue, but several studies have shown that endothelial cells may also be a source. The goal of this study was to determine to what extent TNF, a factor overproduced by uteroplacental tissue in PE pregnancy, may influence uterine artery endothelial cells to contribute to these other PE-specific factors in the maternal circulation. Herein, we use multiple analytical methods to show that uterine artery endothelial cells from pregnant sheep (P-UAEC) on exposure to cytokines can secrete multiple cytokines and chemokines seen in PE women, which may contribute to production of Th17 cells and attraction of these and other cells to the vessel surface. Furthermore, the factors not significantly increased by TNF include those known to be specifically secreted by proinflammatory T cells. This begs the question if endothelium itself is the initial primary orchestrator of chemokine and cytokine imbalance, acting directly and indirectly to promote the symptoms of impaired vasodilation and reduced uteroplacental blood flow. If so, future preventive therapies for PE should be targeted at endothelium as well as immune cells.

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Abstract: The aim of this study was to investigate the mechanism by which chronic stress (CS) induces non-alcoholic fatty liver disease (NAFLD)-like changes, and the role of oxidative stress and the NLRP3 inflammasome in this mechanism. Transcriptomic data extracted from the Sequence Read Archive (SRA) at the NCBI were employed to identify the molecular targets of CS-induced NAFLD. Fifty 8-week-old healthy male Wistar rats were divided into five groups (n = 10 each) as follows: control, CS, CS + mifepristone (CS + Mif), CS + metyrapone (CS + Met), and corticosterone (Cort). The CS, CS + Mif, and CS + Met groups underwent restraint stress training. Rats in the CS + Mif, CS + Met, and Cort groups were administered mifepristone, metyrapone, and corticosterone for 8 weeks. Data showed that CS induced NAFLD-like liver damage via increased glucocorticoids (GCs). Moreover, CS increased malonaldehyde (MDA) levels and decreased superoxide dismutase (SOD) activity in liver and serum samples, suggesting the occurrence of oxidative stress. Furthermore, CS activated various inflammatory pathways via the NLRP3 inflammasome (NLRP3, ASC, caspase-1), which enhanced cytokine levels (IL-1β, IL-6, TNF-α) in liver tissue. Notably, treatment with metyrapone or mifepristone alleviated liver lesions induced by CS, which implies that the GC signalling pathway may be an important mediator of stress-induced liver inflammation. We conclude that GC mediates the development of oxidative stress and inflammation in the liver, and inhibition of GC signalling may be a new therapeutic strategy in NAFLD.

Hepatic thyroid hormone action plays an important role in preventing the development and progression of metabolic liver diseases, as evidenced by the recent success of the receptor-specific agonist resmetirom. The liver enzyme deiodinase type I (DIO1) is important for controlling the local availability of thyroid hormone and is upregulated in metabolically associated steatotic liver disease (MASLD), which is thought to be a compensatory mechanism to enhance local hormone action. However, it remains unclear whether this increase is maintained in later stages of MASLD and whether an induction of Dio1 can provide beneficial metabolic effects. Studying mouse models with different stages of MASLD, we show here that Dio1 mRNA expression and activity are rapidly induced within 1 week by high-caloric dietary intervention. In later stages, this increase was less pronounced. Surprisingly, altered Dio1 mRNA concentration became progressively less well associated with altered DIO1 enzyme activity, suggesting uncoupling of mRNA and protein biosynthesis. In order to enhance DIO1 activity in MASLD development, a transgenic strategy was applied by using an adeno-associated virus-based liver-specific gene therapy with either the Dio1 or Socs3 gene. In either model, DIO1 activity was increased, but neither thyroid hormone target genes nor metabolic parameters were positively affected in the time frame of the experiment. We conclude that hepatic DIO1 biosynthesis becomes progressively disturbed with disease progression in MASLD by a decoupling of its transcript and protein levels, highlighting the key importance of translational processes controlling DIO1 in hepatocytes, which are likely affected by local inflammatory mechanisms.

G protein-coupled receptors (GPCRs) represent a diverse and vital family of membrane proteins that mediate intracellular signaling in response to extracellular stimuli, playing critical roles in physiology and disease. Traditionally recognized as chemical signal transducers, GPCRs have recently been implicated in mechanotransduction, the process of converting mechanical stimuli into cellular responses. This review explores the emerging role of GPCRs in sensing and responding to mechanical forces, with a particular focus on the cardiovascular system. Cardiovascular homeostasis is heavily influenced by mechanical forces such as shear stress, cyclic stretch, and pressure, which are central to both normal physiology and the pathogenesis of diseases such as hypertension and atherosclerosis. GPCRs, including the angiotensin II type 1 receptor (AT1R) and the β2-adrenergic receptor (β2-AR), have demonstrated the ability to integrate mechanical and chemical signals, potentially through conformational changes and/or modulation of lipid interactions, leading to biased signaling. Recent studies highlight the dual activation mechanisms of GPCRs, with β2-AR now serving as a key example of how mechanical and ligand-dependent pathways contribute to cardiovascular regulation. This review synthesizes current knowledge of GPCR mechanosensitivity, emphasizing its implications for cardiovascular health and disease, and explores advancements in methodologies poised to further unravel the mechanistic intricacies of these receptors.

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Abstract: The signalling of kisspeptin-1 through the kisspeptin-1 receptor (KISS1R) is central to mammalian reproduction. Naturally occurring heterozygous KISS1R mutations and Kiss1r +/- knockout mice are less affected than their homozygous counterparts, suggesting that the mutant receptors possibly form oligomers with the wild-type (WT) KISS1R, rescuing the receptor function to some extent. To test this hypothesis, the heterozygous KISS1R mutations R38P, P46Q, S125L and R198G, reported in the literature in cases of delayed puberty, were characterised. In silico analysis predicted that all four mutations affected the receptor function to varying extents, which was substantiated by in vitro studies. Determination of cell surface receptor expression and kisspeptin-stimulated signalling response was carried out post transient transfection of the receptor constructs in CHO cells. Results revealed that these mutations (homozygous condition) impaired the cell surface receptor expression, as quantified by flow cytometry, with a concomitant attenuation of inositol phosphate production. Co-transfection of the WT KISS1R with equal amounts of the mutant receptors, to mimic the heterozygous condition of the mutation in the patients, restored the receptor function and, with increasing amounts of mutant receptors, resulted in attenuation of receptor function. As a direct proof of receptor oligomerisation, co-expression of epitope-tagged KISS1R constructs was carried out. Co-immunoprecipitation and imaging FRET studies revealed that KISS1R forms homo-oligomers in a constitutive manner and that the transmembrane domain 7 contributed to the oligomerisation interface, as demonstrated by the impairment in oligomerisation upon deletion of this domain. Thus, characterisation of heterozygous KISS1R mutations corroborated the oligomerisation status of the KISS1 receptor and helped in establishing a genotype-phenotype association.

Classical activation of the hypothalamic-pituitary-adrenal axis is exerted by the stimulation of pituitary POMC gene transcription and ACTH release by the hypothalamic hormone CRH. In parallel, inflammatory cytokines such as IL6 and LIF also stimulate ACTH release and POMC transcription through the JAK/STAT pathway. In recent years, a particular interest in the role of the EGF pathway for POMC activation was sparked by the identification of causative mutations in the USP8 gene that have been implicated in the formation of pituitary corticotroph adenomas that are the hallmark of Cushing's disease. These mutations were associated with the persistent upregulation of the EGF/EGFR pathway and its putative role in ACTH hypersecretion. In the present work, we reassessed the signaling pathways that are activated in response to EGF in pituitary corticotroph cells using the AtT20 cell model. We confirmed the activation of the MAP kinase pathway by EGF and also showed the activation of the AKT/mTOR and JAK/STAT pathways. Whereas activation of all three pathways appears essential for the stimulation of cell proliferation, only the JAK/STAT pathway, and more specifically STAT3, enhances POMC gene transcription. This action is mapped to a single STAT-binding element of the POMC promoter in contrast to the activation by the other STAT-activating cytokines LIF and IL6. Furthermore, EGF signaling is specifically enhanced by STAT3 but not STAT1 in contrast to LIF-dependent activation. All together, the data identified a unique STAT3-dependent target on the POMC promoter that mediates EGF activation of POMC gene transcription.

Rhodiola crenulata (RC) has been traditionally used for its therapeutic benefits, including alleviating high-altitude sickness, fatigue, and diabetes. Diabetic kidney disease (DKD), a severe complication of diabetes, often leads to progressive renal fibrosis. This study explored the protective effects of RC against kidney fibrosis in DKD rat models, identifying active compounds and their therapeutic targets, with a focus on salidroside (SAL), a key component of RC. After administering RC to DKD rats, network pharmacology analysis identified 22 core components and 141 DKD-related therapeutic targets, with TGFB1 emerging as a primary target in kidney fibrosis. In vivo experiments demonstrated that RC reduced fibrosis markers by decreasing glomerular mesangial expansion, collagen deposition, and myofibroblast proliferation, alongside lowering TGF-β1 levels. In vitro analyses revealed that SAL inhibited high glucose-induced fibroblast activation and suppressed TGF-β1 expression in proximal renal tubular epithelial cells (PTECs), suggesting its direct role in slowing fibrosis progression. These findings indicate that the antifibrotic effects of RC in DKD may be attributed to SAL's ability to regulate fibroblast activity and suppress TGF-β1, highlighting its potential as a therapeutic component for DKD management.

Obesity is known to have detrimental effects on female fertility, influencing both ovarian and endometrial functions. There is evidence that endometrial function is altered in obese and/or insulin-resistant women. Metformin, an insulin-sensitizing drug, has shown potential in treating metabolic and reproductive disorders, including polycystic ovary syndrome (PCOS) and may enhance fertility outcomes by improving endometrial dysfunction. Using a mouse model, this study aimed to investigate how a high-fat diet impacts endometrial-specific protein expression and whether metformin can mitigate these effects. C57BL/6N mice were fed a standard or high-fat diet and either received metformin treatment or did not. Proteomic analyses revealed significant alterations in endometrial protein expression due to the high-fat diet, while metformin administration appeared to restore many of these changes to normal levels. Metformin's impact was evident through alterations in specific proteins associated with reproductive health and metabolic functions, such calcium-independent phospholipase A2-gamma, ATP-binding cassette sub-family D member 1, RAC-beta serine/threonine-protein kinase, acyl-CoA:lysophosphatidylglycerol acyltransferase 1, O-GlcNAcase, scavenger receptor class A member 3, protein kinase C beta type, sortilin, beta-2-microglobulin and apolipoprotein C-III. These results suggest a potential therapeutic role for metformin in normalizing endometrial protein expression, providing insights into how this drug could improve fertility outcomes in obese or insulin-resistant females, besides normalizing ovulation patterns. Overall, this study enhances our understanding of the relationship among obesity, endometrial function and metformin's therapeutic potential, offering a foundation for further research into reproductive health and metabolic disorders.

Osteoporosis diagnoses are increasing in the ageing population, and although some treatments exist, these have several disadvantages, highlighting the need to identify new drug targets. G protein-coupled receptors (GPCRs) are transmembrane proteins whose surface expression and extracellular activation make them desirable drug targets. Our previous studies have identified 144 GPCR genes to be expressed in primary human osteoclasts, which could provide novel drug targets. The development of high-throughput assays to assess osteoclast activity would improve the efficiency at which we could assess the effect of GPCR activation on human bone cells and could be utilised for future compound screening. Here, we assessed the utility of a high-content imaging (HCI) assay that measured cytoplasmic-to-nuclear translocation of the nuclear factor of activated T cells-1 (NFATc1), a transcription factor that is essential for osteoclast differentiation, and resorptive activity. We first demonstrated that the HCI assay detected changes in NFATc1 nuclear translocation in human primary osteoclasts using GIPR as a positive control, and then developed an automated analysis platform to assess NFATc1 in nuclei in an efficient and unbiased manner. We assessed six GPCRs simultaneously and identified four receptors (FFAR2, FFAR4, FPR1 and GPR35) that reduced osteoclast activity. Bone resorption assays and measurements of TRAP activity verified that activation of these GPCRs reduced osteoclast activity, and that receptor-specific antagonists prevented these effects. These studies demonstrate that HCI of NFATc1 can accurately assess osteoclast activity in human cells, reducing observer bias and increasing efficiency of target detection for future osteoclast-targeted osteoporosis therapies.

Somatostatin (Sst) is an inhibitory regulator of many hormones. The prenatal environment impacts an offspring's risk to type 2 diabetes in adulthood. However, the effect of maternal Sst deficiency on glucose and insulin metabolism in offspring and metabolic disease risk in their adult life has been poorly understood. The study was to investigate the impact of a lack of maternal Sst exposure in mouse male and female offspring on diet-induced changes in glucose metabolism and adiposity. Sst knockout offspring, SstKO born to the Sst-heterozygous dams or SstKO-MSD born to the Sst-homozygous dams were fed either a regular diet (CD) or a high-fat diet (HFD) at 3-week-old for 15 weeks. Body weight and blood glucose levels were monitored. Glucose and insulin tolerance tests were performed. Plasma hormone levels and gene expression in the hypothalamus were investigated. The results demonstrated that only male SstKO-MSD offspring developed obesity accompanied by severe insulin and leptin resistance after HFD challenge. Insulin secretion was reduced in both basal and oral glucose-challenged conditions in the CD-fed male SstKO-MSD mice. A reduced ratio of islet area to pancreas area was noted in SstKO-MSD mice in both sexes. Plasma levels of glucagon, Glp1 and Pyy were elevated in both male and female SstKO and SstKO-MSD mice. mRNA expression of leptin receptor, FoxO1, Npy and Agrp was downregulated in male SstKO-MSD mice. These results demonstrate that a lack of fetal somatostatin exposure impairs the islet development in offspring and increases risk of obesity, insulin resistance and leptin resistance later in life.