Icariside II, a flavonoid glycoside, is the main component found invivo after the administration of Herba epimedii and has shown some pharmacological effects, such as prevention of osteoporosis and enhancement of immunity. Increased levels of marrow adipose tissue are associated with osteoporosis. S100 calcium-binding protein A16 (S100A16) promotes the differentiation of bone marrow mesenchymal stem cells (BMSCs) into adipocytes. This study aimed to confirm the anti-lipidogenesis effect of Icariside II in the bone marrow by inhibiting S100A16 expression. We used ovariectomy (OVX) and BMSC models. The results showed that Icariside II reduced bone marrow fat content and inhibited BMSCs adipogenic differentiation and S100A16 expression, which correlated with lipogenesis. Overexpression of S100A16 eliminated the inhibitory effect of Icariside II on lipid formation. β-catenin participated in the regulation adipogenesis mediated by Icariside II/S100A16 in the bone. In conclusion, Icariside II protects against OVX-induced bone marrow adipogenesis by downregulating S100A16, in which β-catenin might also be involved.

G6PC2 encodes a glucose-6-phosphatase catalytic subunit that opposes the action of glucokinase in pancreatic islets, thereby modulating the sensitivity of insulin and glucagon secretion to glucose. In mice, G6pc2 is expressed at ~20-fold higher levels in β-cells than in α-cells, whereas in humans G6PC2 is expressed at only ~5-fold higher levels in β-cells. We therefore hypothesize that G6PC2 likely influences glucagon secretion to a greater degree in humans. With a view to generating a humanized mouse that recapitulates augmented G6PC2 expression levels in α-cells, we sought to identify the genomic regions that confer differential mouse G6pc2 expression in α-cells versus β-cells as well as the evolutionary changes that have altered this ratio in humans. Studies in islet-derived cell lines suggest that the elevated G6pc2 expression in mouse β-cells versus α-cells is mainly due to a difference in the relative activity of the proximal G6pc2 promoter in these cell types. Similarly, the smaller difference in G6PC2 expression between α-cells and β-cells in humans is potentially explained by a change in relative proximal G6PC2 promoter activity. However, we show that both glucocorticoid levels and multiple differences in the relative activity of eight transcriptional enhancers between mice and humans likely contribute to differential G6PC2 expression. Finally, we show that a mouse-specific non-coding RNA, Gm13613, whose expression is controlled by G6pc2 enhancer I, does not regulate G6pc2 expression, indicating that altered expression of Gm13613 in a humanized mouse that contains both the human promoter and enhancers should not affect G6PC2 function.

Genetic variants involving steroidogenic acute regulatory protein cause lipoid congenital adrenal hyperplasia, which is characterized by impaired steroidogenesis in the adrenal glands and gonads. Functional assessment of variant STAR proteins is necessary for accurate genetic diagnosis. Ideally, steroidogenic cells should be used to assess the functionality of STAR proteins, but the presence of endogenous STARs in steroidogenic cells precludes such a method. Here, we generated Star-edited cells from steroidogenic Y1 mouse adrenocortical tumor cells by genome editing. Star-edited Y1 cells exhibited very low but measurable cAMP-dependent pregnenolone production. Furthermore, stimulation of the cAMP pathway for two weeks resulted in the formation of lipid droplets in the cytoplasm of Star-edited Y1 cells, which resembled the histology of the adrenal glands of patients with lipoid congenital adrenal hyperplasia. The steroidogenic defect of Star-edited Y1 cells can be restored by transient over-expression of mouse Star. We found that human STAR can also restore defective steroidogenesis of Star-edited Y1 cells, and were able to construct a novel in vitro system to evaluate human STAR variants. Collectively, we established Star-edited Y1 cells that retain the steroidogenic pathway downstream the Star protein. Star-edited Y1 cells recapitulate the functional and morphological changes of lipoid congenital adrenal hyperplasia, and can be used to evaluate the functionality of human STAR variants.

Pentraxin 3 (PTX3) is a prototypic humoral soluble pattern-recognition molecule known to function in immunity-related inflammation. Given the lack of information on the precise functions of PTX3 in the pathogenesis of Graves’ orbitopathy (GO), this study investigated the role of PTX3 in the inflammation and adipogenesis mechanism of GO. We first compared the PTX3 expression between orbital tissues from patients with GO and normal controls, using real-time polymerase chain reaction, which estimated significantly higher PTX3 transcript levels in the GO tissues than in the normal tissues. In addition, PTX3 production was markedly increased upon interleukin (IL)-1β and adipogenic stimulation. We then evaluated the effects of silencing PTX3 in primary orbital fibroblast cultures by analyzing the expression levels of pro-inflammatory cytokines, adipogenesis-related proteins, and downstream transcription factors in cells transfected with or without a small interfering RNA against PTX3, using western blot. Silencing PTX3 attenuated the IL-1β-induced secretion of pro-inflammatory cytokines, including IL-6, IL-8, monocyte chemotactic protein-1, intercellular adhesion molecule-1, and cyclooxygenase-2, and suppressed the IL-1β-mediated activation of p38 kinase, nuclear factor-κB, and extracellular signal-regulated kinase. Moreover, PTX3 knockdown suppressed adipogenic differentiation, as assessed using Oil Red O staining, as well as the expression of adipogenesis-associated transcription factors including peroxisome proliferator activator-γ, CCAAT/enhancer-binding proteins α and β, adipocyte protein 2, adiponectin, and leptin. Thus, this study suggests that PTX3 plays a significant role in the pathogenesis of GO and may serve as a novel therapeutic target for the condition.

Receptor activity-modifying proteins (RAMPs) modulate the expression and activity of numerous G protein-coupled receptors, primarily those within class B1. These receptors have important physiological roles, including in the regulation of food intake, energy metabolism, and glucose homeostasis. Dysregulation of these pathways can lead to obesity and diabetes mellitus, which present an ever-expanding global challenge. Whilst the roles of class B1 receptors and their peptide agonists in obesity and diabetes have been investigated, the contribution of RAMPs is less well understood. This review summarises the results of RAMP knockout studies, highlighting the involvement of these proteins in the incidence of disease. It then moves to discuss how receptor, RAMP, and agonist expression changes in disease states, and the benefits (or detriments) of these agonists to the pathways implicated in disease pathophysiology. Whilst much of the data centres around the calcitonin family of receptors, as their interactions with RAMPs are well established, this review then discusses receptors whose role in obesity and diabetes is well founded, but the significance of whose interactions with RAMPs is more recently emerging. The conclusion of this study of the literature is, however, that the information surrounding RAMPs is conflicting and multifaceted, and more research is required to fully understand their contribution to obesity and diabetes.

Wnt/β-catenin signaling is essential for adrenocortical development. Zinc and ring finger 3 (ZNRF3), an E3 ubiquitin ligase that attenuates Wnt/β-catenin signaling, is negatively regulated by R-spondin via an extracellular domain that is partially encoded by exon 2 of ZNRF3. We recently identified ZNRF3 exon 2 deletions in three individuals with congenital adrenal hypoplasia. ZNRF3 exon 2 deletion impairs R-spondin binding, thereby attenuating β-catenin expression, eventually developing congenital adrenal hypoplasia. To elucidate the influence of ZNRF3/Znrf3 exon 2 deletion on adrenocortical development, we generated homozygous Znrf3 exon 2 deletion (Znrf3 ^Δ2/Δ2) mice. The adrenal glands of Znrf3 ^Δ2/Δ2 mice did not show gross morphological changes at birth but became enlarged with age. Moderate hyperplasia of the zona fasciculata (ZF), dispersed medulla arrangement, and a radially spreading zone comprised of cells with large nuclei between the ZF and medulla were observed at 6 weeks of age. Immunohistochemistry revealed low levels of 20α-hydroxysteroid dehydrogenase, a marker of the adrenal X-zone, in Znrf3 ^Δ2/Δ2 mice. Plasma ACTH and serum corticosterone levels in Znrf3 ^Δ2/Δ2 mice did not differ significantly from those in wild-type mice. Transcriptome analyses of the adrenal glands revealed substantial downregulation of X-zone markers but no significant changes in the expression of genes involved in the Wnt/β-catenin signaling pathway. These results show that a species-specific difference in the effects of ZNRF3/Znrf3 exon 2 deletions in humans and mice; Znrf3 ^Δ2/Δ2 mice do not develop congenital adrenal hypoplasia but instead exhibit moderate ZF hyperplasia, dispersed medulla arrangement, and X-zone dysplasia.

MafA is a key transcriptional regulator of pancreatic islet β-cell function. Its target genes include those encoding preproinsulin and the glucose transporter Glut2 (Slc2a2); thus MafA function is essential for glucose-stimulated insulin secretion. Expression levels of MafA are reduced in β-cells of diabetic mouse models and human subjects, suggesting that β-cell dysfunction associated with type 2 diabetes is attributable to loss of MafA. On the other hand, MafA is transcriptionally upregulated by incretin hormones through activation of CREB and its co-activator CRTC2. β-cell-specific expression of MafA relies on a distal enhancer element. However, the precise mechanism by which CREB-CRTC2 regulates the enhancer and proximal promoter regions of MafA remains unclear. In this report, we analyzed previously published ChIP-seq data and found that CREB and NeuroD1, a β-cell-enriched transactivator, bound to both the promoter and enhancer regions of human MAFA. A series of reporter assays revealed that CREB activated the enhancer through a conserved cAMP-responsive element (CRE), but stimulated MAFA promoter activity even when the putative CRE was deleted. Two E-box elements and a CCAAT motif which bind NeuroD1 and ubiquitous NF-Y transcription factors, respectively, were necessary for transcriptional activation of the MAFA promoter by CREB. Genome-wide analysis of CREB-bound loci in β-cells revealed that they were enriched with CCAAT motifs. Furthermore, promoter analysis of Isl1 gene encoding a β-cell-enriched transcription factor revealed that a CRE-like element and two CCAAT-motifs, but not E-box, were necessary for activation by CREB. There results provide clues to elucidate the detailed mechanism by which CREB regulates MafA as well as β-cell-specific genes.

Pregnancy requires metabolic adaptations in order to meet support fetal growth with nutrient availability. In this study, the influence of pregnancy on metabolically active organs (adipose tissues in particular) was investigated. Our results showed that maternal weight and adipose mass presented dynamic remodeling in the periparturient mice. Meanwhile, pregnancy mice displayed obvious glucose intolerance and insulin resistance in late pregnancy as compared to non-pregnancy, which were partially reversed at parturition. Further analyses revealed that different fat depots exhibited site-specific adaptions of morphology and functionality as pregnancy advanced. Brown and inguinal white adipose tissue (BAT and IngWAT) exhibited obviously decreased thermogenic activity; by contrast, gonadal white adipose tissue (GonWAT) displayed remarkably increased lipid mobilization. Notably, we found that mammary gland differentiation was enhanced in IngWAT, followed by BAT but not in GonWAT. These result indicated that brown and white adipose tissues might synergistically play a crucial role in maintaining the maximum of energy supply for mother and fetus, which facilitates the mammary duct luminal epithelium development as well as the growth and development of fetus. Accompanied with adipose adaptation, however, our results revealed that the liver and pancreas also displayed significant metabolic adaptability, which together tended to trigger the risk of maternal metabolic diseases. Importantly, pregnancy-dependent obesity in our mice model resembled the disturbed metabolic phenotypes of pregnant women such as hyperglyceridemia and hypercholesterolemia. Our findings in this study could provide valuable clues for better understanding the underlying mechanisms of metabolic maladaptation and facilitate the development of the prevention and treatment of metabolic diseases.

The objective was to assess the potential differential effects of human versus mouse growth hormone in vivo, given that human unlike mouse growth hormone can bind prolactin as well as the growth hormone receptor. To this end, a transgenic CD-1 mouse expressing human but not mouse growth hormone was generated, and the phenotypes of male mice fed with a regular chow or high-fat diet were assessed. Pancreas and epididymal white adipose tissue gene expression and/or related function were targeted as the pancreas responds to both prolactin and growth hormone receptor signaling, and catabolic effects like lipolytic activity are more directly attributable to growth hormone and growth hormone receptor signaling. The resulting human growth hormone-expressing mice are smaller than wild-type CD-1 mice, despite higher body fat and larger adipocytes, but both mouse types grow at the same rate with similar bone densities. Unlike wild-type mice, there was no significant delay in glucose clearance in human growth hormone-expressing mice when assessed at 8 versus 24 weeks on a high-fat diet. However, both mouse types showed signs of hepatic steatosis that correlated with elevated prolactin but not growth hormone RNA levels. The larger adipocytes in human growth hormone-expressing mice were associated with modified leptin (higher) and adiponectin (lower) RNA levels. Thus, while limited to observations in the male, the human growth hormone-expressing mice exhibit signs of growth hormone insufficiency and adipocyte dysfunction as well as an initial resistance to the negative effects of high-fat diet on glucose clearance.

In this study, we investigate the effects of miRNA-138-5p and probable G-protein coupled receptor 124 (GPR124)-regulated inflammasome and downstream leukemia inhibitory factor (LIF)–STAT and adhesion molecule signaling in human decidual stromal cells. After informed consent was obtained from women aged 25–38 years undergoing surgical termination of the normal pregnancy and spontaneous miscarriage after 6–9 weeks of gestation, human decidual stromal cells were extracted from the decidual tissue. Extracellular vesicles (EVs) with microRNA (miRNA) between cells have been regarded as critical factors for embryo–maternal interactions on embryo implantation and programming of human pregnancy. MicroRNA-138-5p acts as the transcriptional regulator of GPR124 and the mediator of downstream inflammasome. LIF-regulated STAT activation and expression of integrins might influence embryo implantation. Hence, a better understanding of LIF–STAT and adhesion molecule signaling would elucidate the mechanism of microRNA-138-5p- and GPR124-regulated inflammasome activation on embryo implantation and pregnancy. Our results show that microRNA-138-5p, purified from the EVs of decidual stromal cells, inhibits the expression of GPR124 and the inflammasome, and activates the expression of LIF–STAT and adhesion molecules in human decidual stromal cells. Additionally, the knockdown of GPR124 and NLRP3 through siRNA increases the expression of LIF–STAT and adhesion molecules. The findings of this study help us gain a better understanding the role of EVs, microRNA-138-5p, GPR124, inflammasomes, LIF–STAT, and adhesion molecules in embryo implantation and programming of human pregnancy.