Journal of Molecular Endocrinology

The prostanoid G protein-coupled receptor (GPCR) EP2 is widely expressed and implicated in endometriosis, osteoporosis, obesity, pre-term labour, and cancer. Internalisation and intracellular trafficking are critical for shaping GPCR activity, yet little is known regarding spatial programming of EP2 signalling and whether this can be exploited pharmacologically. Using three EP2-selective ligands that favour activation of different EP2 pathways, we show that EP2 undergoes limited agonist-driven internalisation but is constitutively internalised via dynamin-dependent, β-arrestin-independent pathways...

Postmenopausal osteoporosis (OP) is a prevalent skeletal disease with not fully understood molecular mechanisms. This study aims to investigate the role of circular RNA (circRNA) in postmenopausal OP and to elucidate the potential mechanisms of the circRNA-miRNA-mRNA regulatory network. We obtained circRNA and miRNA expression profiles from postmenopausal OP patients from the Gene Expression Omnibus database. By identifying differentially expressed circRNAs and miRNAs, we constructed a circRNA-miRNA-mRNA network and identified key genes associated with OP...

The Estrogen Receptor-alpha (ER) drives 75% of breast cancers. On activation, the ER recruits and assembles a 1-2 MDa transcriptionally active complex. These complexes can modulate tumour growth, and understanding the roles of individual proteins within these complexes can help identify new therapeutic targets. Here, we present the discovery of ER and ZMIZ1 within the same multi-protein assembly by quantitative proteomics, and validated by proximity ligation assay. We characterise ZMIZ1 function by demonstrating a significant decrease in the proliferation of ER-positive cancer cell lines...

Humans with the mutation Y509C in transducin beta like 1 X-linked (TBL1X HGNC ID HGNC:11585) have been reported to present with the combination of central congenital hypothyroidism and impaired hearing. TBL1X belongs to the WD40 repeat-containing protein family, is part of NCoR and SMRT corepressor complexes, and thereby involved in thyroid hormone signaling. In order to investigate the effects of the Y509C mutation in TBL1X on cellular thyroid hormone action, we aimed to generate a hemizygous male mouse cohort carrying the Tbl1x Y459C mutation which is equivalent to the human TBL1X Y509C mutation using CRISPR/Cas9 technology...

White adipose tissue (WAT) requires extracellular Ca2+ influx for lipolysis, differentiation, and expansion. This partly occurs via plasma membrane Ca2+ voltage-dependent channels (CaVs). However, WFA exists in different depots whose function varies with age, sex, and location. To explore whether their CaV expression profiles also differ we used RNAseq and qPCR on gonadal, mesenteric, retroperitoneal, and inguinal subcutaneous fat depots from rats of different ages and sex. CaV expression was found dependent on age, sex, and WFA location...

The exact neural construct underlying the dynamic secretion of gonadotrophin-releasing hormone (GnRH) has only recently been identified despite the detection of multiunit electrical activity volleys associated with pulsatile luteinising hormone (LH) secretion four decades ago. Since the discovery of kisspeptin/neurokinin B/dynorphin neurons in the mammalian hypothalamus, there has been much research into the role of this neuronal network in controlling the oscillatory secretion of gonadotrophin hormones. In this review, we provide an update of the progressive application of cutting-edge techniques combined with mathematical modelling by the neuroendocrine community, which are transforming the functional investigation of the GnRH pulse generator...

Trophoblast stem cells (TSC) are a proliferative multi-potent population derived from the trophectoderm of the blastocyst, which will give rise to all the functional cell types of the trophoblast compartment of the placenta. The isolation and culture of TSC in vitro represent a robust model to study mechanisms of trophoblast differentiation into mature cells both in successful and diseased pregnancy. Despite the highly conserved functions of the placenta, there is extreme variability in placental morphology, fetal/maternal interface, and development among eutherian mammals...

Follicle-stimulating hormone (FSH) accelerates osteoporosis in postmenopausal women, while the underlying mechanism remains uncharacterized. N6-methyladenosine (m6A) is one of the most important regulations in the development of osteoporosis. In this study, we aimed to investigate the role of FSH in m6A modification, and osteoclast function. Here, we showed that FSH upregulated m6A levels in osteoclasts via stimulating methyltransferase-like 3 (METTL3) protein expression. FSH enhanced osteoclast migration, while the knockdown of METTL3 eliminated this enhancement...

Enteroendocrine cells located along the gastrointestinal epithelium sense different nutrients/luminal contents that trigger the secretion of a variety of gut hormones with different roles in glucose homeostasis and appetite regulation. The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are involved in the regulation of insulin secretion, appetite, food intake and body weight after their nutrient-induced secretion from the gut. GLP-1 mimetics have been developed and used in the treatment of type 2 diabetes mellitus and obesity...

Mechanisms underlying limitations in glucose supply that restrict fetal growth are not well established. IGF-1 is an important regulator of fetal growth and IGF-1 bioavailability is markedly inhibited by IGFBP-1 especially when the binding protein is hyperphosphorylated. We hypothesized that the AMPK-mTORC1 pathway increases IGFBP-1 phosphorylation in response to glucose deprivation. Glucose deprivation in HepG2 cells activated AMPK and TSC2, inhibited mTORC1 and increased IGFBP-1 secretion and site-specific phosphorylation...

Extra-adrenal de-novo aldosterone (Aldo) production has been described inconsistently. Systematic data based upon state-of-the-art technology including validated controls are sparse. We hypothesized that aldosterone synthase (CYP11B2) expression and de-novo Aldo production are absent in non-adrenal human cell lines, either immortalized cell lines or commercially available primary cell lines, including peripheral blood mononuclear cells (PBMCs) of individuals without and with primary hyperaldosteronism (PA)...

Several human disorders are caused by genetic or epigenetic changes involving the GNAS locus on chromosome 20q13.3 that encodes the alpha-subunit of the stimulatory G protein (Gsα) and several splice variants thereof. Thus, pseudohypoparathyroidism type Ia (PHP1A) is caused by heterozygous inactivating mutations involving the maternal GNAS exons 1-13 resulting in characteristic abnormalities referred to as Albright's hereditary osteodystrophy (AHO) that are associated with resistance to several agonist ligands, particularly to parathyroid hormone (PTH), thereby leading to hypocalcemia and hyperphosphatemia...

The early phase of type 2 diabetes (T2DM) is characterised by insulin resistance, which can initially be compensated by elevated insulin secretion. However, as postulated by the workload hypothesis, over time harming insulin requirements contribute to β-cell dysfunction and death. The mechanisms behind this transition are complex and not fully understood but involve factors such as endoplasmic reticulum (ER) stress raised by gluco-/lipotoxicity. To investigate the effect of excessive insulin folding on ER luminal hydrogen peroxide (H2O2) generation, ER stress and viability, insulin was expressed glucose-independently by a doxycycline-regulated Tet-On system in insulin-producing RINm5F cells...

N1-methylnicotinamide (MNAM), a product of methylation of nicotinamide through nicotinamide N-methyltransferase, displays anti-diabetic effects in male rodents. This study aimed to evaluate the ameliorative potential of MNAM on glucose metabolism in gestational diabetes mellitus (GDM) model. C57BL/6N mice were fed with high fat diet (HFD) for 6 weeks before pregnancy and throughout gestation to establish the GDM model. Pregnant mice were treated with 0.3% or 1% MNAM during gestation. MNAM supplementation in CHOW diet and HFD both impaired the glucose tolerance at gestational day 14...

There is increasing interest in retinoic acid (RA) as a regulator of the complex biological processes underlying the cognitive functions performed by the brain. The importance of RA in brain function is underlined by the brain's high efficiency in converting vitamin A into RA. One crucial action of RA in the brain is dependent on RA receptor α (RARα) transport out of the nucleus, where it no longer regulates transcription but carries out non-genomic functions. RARα, when localised in the cytoplasm, particularly in neuronal dendrites, acts as a translational suppressor...

In the endoplasmic reticulum (ER) lumen, glucose-6-phosphatase catalytic subunit 1 and 2 (G6PC1; G6PC2) hydrolyze glucose-6-phosphate (G6P) to glucose and inorganic phosphate whereas hexose-6-phosphate dehydrogenase (H6PD) hydrolyzes G6P to 6-phosphogluconate (6PG) in a reaction that generates NADPH. 11β-hydroxysteroid dehydrogenase type 1 (HSD11B1) utilizes this NADPH to convert inactive cortisone to cortisol. HSD11B1 inhibitors improve insulin sensitivity whereas G6PC inhibitors are predicted to lower fasting blood glucose (FBG)...

Suboptimal in utero environments such as poor maternal nutrition and gestational diabetes can impact fetal birth weight and the metabolic health trajectory of the adult offspring. Fetal growth is associated with alterations in placental mechanistic target of rapamycin (mTOR) signaling; it is reduced in fetal growth restriction and increased in fetal overgrowth. We previously reported that when metabolically challenged by a high-fat diet, placental mTORKO (mTORKOpl) adult female offspring develop obesity and insulin resistance, whereas placental TSC2KO (TSC2KOpl) female offspring are protected from diet-induced obesity and maintain proper glucose homeostasis...

Several studies provide evidence that erythropoietin (EPO) could play an important role in the recovery of the heart subjected to ischemia-reperfusion. In this regard, it has been suggested that EPO could be involved in protein kinase B (Akt) activation as a cell survival protein. The aim of the present study was to investigate the effects of EPO on the Akt/glycogen synthase kinase 3 beta (GSK-3β) pathway in the presence or absence of wortmannin (W, Akt inhibitor) and its relationship with mitochondrial morphology and function preservation in ischemic-reperfused rat hearts...

Excess growth hormone (GH) has been implicated in multiple cancer types and there is increasing interest in the development of therapeutic inhibitors targeting GH-GH receptor (GHR) signalling. Here we describe a panel of anti-GH monoclonal antibodies (mAbs) generated using a hybridoma approach and identify two novel inhibitory mAbs (1-8-2 and 1-46-3) that neutralised GH signalling. mAbs 1-8-2 and 1-46-3 exhibited strong inhibitory activity against GH-dependent cell growth in a Ba/F3-GHR cell viability assay, with EC50 values of 1...

Metabolic syndrome is a group of risk factors that increase the risk of developing metabolic and cardiovascular disease (CVD) and include obesity, dyslipidemia, insulin resistance, atherosclerosis, hypertension, coronary artery disease, and heart failure. Recent research indicates that excessive production of aldosterone and associated activation of mineralocorticoid receptors (MR) impair insulin metabolic signaling, promote insulin resistance, and increase the risk of developing metabolic syndrome and CVD...