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Jéssyca Aparecida Soares Giesen, Wender do Nascimento Rouver, Eduardo Damasceno Costa, Virgínia Soares Lemos and Roger Lyrio dos Santos

Progesterone seems to play a role in cardiovascular physiology since its receptors are expressed on endothelial cells from both sexes of mammals. However, little is known about its role on the coronary circulation. Thus, this study aims to evaluate the effect of acute administration of progesterone on the coronary bed and the endothelial pathways involved in this action in normotensive rats of both sexes. A dose–response curve of progesterone (1–50 μmol/L) in isolated hearts using the Langendorff preparation was performed. Baseline coronary perfusion pressure (CPP) was determined, and the vasoactive effect of progesterone was evaluated before and after infusion with Nω-nitro-L-arginine methyl ester (L-NAME), indomethacin, catalase, and Tiron. The analysis of nitric oxide (NO) and superoxide anion (O2 · ) was performed by DAF-2DA and DHE, respectively. Female group showed higher CPP. Nevertheless, progesterone promoted a similar relaxing response in both sexes. The use of L-NAME increased vasodilatory response in both sexes. When indomethacin was used, only the males showed a reduced relaxing response, and in the combined inhibition with L-NAME, indomethacin, and catalase, or with the use of Tiron, only the females presented reduced responses. NO and O2 ·− production has increased in female group, while the male group has increased only NO production. Our results suggest that progesterone is able to modulate vascular reactivity in coronary vascular bed with a vasodilatory response in both sexes. These effects seem to be, at least in part, mediated by different endothelial pathways, involving NO and EDH pathways in females and NO and prostanoids pathways in males.

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Peng Xu, John J Gildea, Chi Zhang, Prasad Konkalmatt, Santiago Cuevas, Dora Bigler Wang, Hanh T Tran, Pedro A Jose and Robin A Felder

Gastrin, secreted by stomach G cells in response to ingested sodium, stimulates the renal cholecystokinin B receptor (CCKBR) to increase renal sodium excretion. It is not known how dietary sodium, independent of food, can increase gastrin secretion in human G cells. However, fenofibrate (FFB), a peroxisome proliferator-activated receptor-α (PPAR-α) agonist, increases gastrin secretion in rodents and several human gastrin-secreting cells, via a gastrin transcriptional promoter. We tested the following hypotheses: (1.) the sodium sensor in G cells plays a critical role in the sodium-mediated increase in gastrin expression/secretion, and (2.) dopamine, via the D1R and PPAR-α, is involved. Intact human stomach antrum and G cells were compared with human gastrin-secreting gastric and ovarian adenocarcinoma cells. When extra- or intracellular sodium was increased in human antrum, human G cells, and adenocarcinoma cells, gastrin mRNA and protein expression/secretion were increased. In human G cells, the PPAR-α agonist FFB increased gastrin protein expression that was blocked by GW6471, a PPAR-α antagonist, and LE300, a D1-like receptor antagonist. LE300 prevented the ability of FFB to increase gastrin protein expression in human G cells via the D1R, because the D5R, the other D1-like receptor, is not expressed in human G cells. Human G cells also express tyrosine hydroxylase and DOPA decarboxylase, enzymes needed to synthesize dopamine. G cells in the stomach may be the sodium sensor that stimulates gastrin secretion, which enables the kidney to eliminate acutely an oral sodium load. Dopamine, via the D1R, by interacting with PPAR-α, is involved in this process.

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Lucia Kořínková, Martina Holubová, Barbora Neprašová, Lucie Hrubá, Veronika Pražienková, Michal Bencze, Martin Haluzík, Jaroslav Kuneš, Lenka Maletínská and Blanka Železná

Lack of leptin production in ob/ob mice results in obesity and prediabetes that could be partly reversed by leptin supplementation. In the hypothalamus, leptin supports the production of prolactin-releasing peptide (PrRP), an anorexigenic neuropeptide synthesized and active in the brain. In our recent studies, the palmitoylated PrRP analog palm11-PrRP31 showed a central anorexigenic effect after peripheral administration. This study investigates whether PrRP could compensate for the deficient leptin in ob/ob mice. In two separate experiments, palm11-PrRP31 (5 mg/kg) and leptin (5 or 10 μg/kg) were administered subcutaneously twice daily for 2 or 8 weeks to 8- (younger) or 16-(older) week-old ob/ob mice, respectively, either separately or in combination. The body weight decreasing effect of palm11-PrRP31 in both younger and older ob/ob mice was significantly powered by a subthreshold leptin dose, the combined effect could be then considered synergistic. Leptin and palm11-PrRP31 also synergistically lowered liver weight and blood glucose in younger ob/ob mice. Reduced liver weight was linked to decreased mRNA expression of lipogenic enzymes. In the hypothalamus of older ob/ob mice, two main leptin anorexigenic signaling pathways, namely, Janus kinase, signal transducer and activator of transcription-3 activation and AMP-activated protein kinase de-activation, were induced by leptin, palm11-PrRP31, and their combination. Thus, palm11-PrRP31 could partially compensate for leptin deficiency in ob/ob mice. In conclusion, the results demonstrate a synergistic effect of leptin and our lipidized palm11-PrRP31 analog.

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Mohamed H Noureldein, Sara Bitar, Natalie Youssef, Sami Azar and Assaad A Eid

Diabetic dysbiosis has been described as a novel key player in diabetes and diabetic complications. However, the cellular/molecular alterations associated with dysbiosis remain poorly characterized. For that, control, non-obese type 2 diabetic MKR mice and MKR mice treated with butyrate were used to delineate the epigenetic, cellular and molecular mechanisms by which dysbiosis associated with diabetes induces colon shortening and inflammation attesting to gastrointestinal disturbance. Our results show that dysbiosis is associated with T2DM and characterized by reduced Bacteroid fragilis population and butyrate-forming bacteria. The reduction of butyrate-forming bacteria and inadequate butyrate secretion result in alleviating HDAC3 inhibition and altering colon permeability. The observed changes are also associated with an increase in ROS production, a rise in NOX4 proteins, and a shift in the inflammatory markers, where IL-1β is increased and IL-10 and IL-17α are reduced. Treatment with butyrate restores the homeostatic levels of NOX4 and IL-1β. In summary, our data suggest that in T2DM, dysbiosis is associated with a reduction in butyrate content leading to increased HDAC3 activity. Butyrate treatment restores the homeostatic levels of the inflammatory markers and reduces ROS production known to mediate diabetes-induced colon disturbance. Taken together, our results suggest that butyrate could be a potential treatment to attenuate diabetic complications.

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Rubab Akbar, Kamran Ullah, Tanzil Ur Rahman, Yi Cheng, Hai-Yan Pang, Lu-Yang Jin, Qi-Jing Wang, He-Feng Huang and Jian-Zhong Sheng

Receptive endometrium is a prerequisite for successful embryo implantation, and it follows that poor endometrial receptivity is a leading cause of implantation failure. miRNAs play important roles as epigenetic regulators of endometrial receptivity and embryo implantation through post-transcriptional modifications. However, the mechanisms of action of many miRNAs are poorly understood. In this study, we investigated the role of the miR-183 family, comprising three miRNAs (miR-183-5p, miR-182-5p, and miR-96-5p) in endometrial receptivity and embryo implantation. The miR-183 family shows estrogen-dependent upregulation in endometrial Ishikawa (IK) cells. The miR-183 family also has a positive role in migration and proliferation of IK cells. Furthermore, JAr spheroid attachment experiments show that attachment rates were significantly decreased after treatment of IK cells with inhibitors for miR-183-5p and miR-182-5p and increased after treatment with miR-183-5p-mimic and miR-96-5p-mimic, respectively. The downstream analysis shows that catenin alpha 2 (CTNNA2) is a potential target gene for miR-183-5p, and this was confirmed in luciferase reporter assays. An in vivo mouse pregnancy model shows that inhibition of miR-183-5p significantly decreases embryo implantation rates and increases CTNNA2 expression. Downregulation of CTNNA2 in endometrial cells by miR-183-5p may be significant in mediating estrogenic effects on endometrial receptivity. In conclusion, miR-183-5p and the CTNNA2 gene may be potential biomarkers for endometrial receptivity and may be useful diagnostic and therapeutic targets for successful embryo implantation.

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Xiaoxia Che, Fangfang Jian, Chen Chen, Chang Liu, Gedan Liu and Weiwei Feng

Polycystic ovary syndrome (PCOS) is the most common endocrine disorder among reproductive-age women. Women with PCOS have a 2.7-fold increased risk for developing endometrial cancer (EC). This study was performed to investigate the potential stimulatory effects of serum exosomes isolated from patients with PCOS on EC cell lines and to explore the underlying mechanism. EC cell lines exposed to exosomes derived from PCOS patients serum exhibited an enhanced migration and invasion phenotype. Next, sequence-based analysis of exosomal miRNA was conducted to screen the differentially expressed miRNAs in serum exosomes from PCOS patients and normal controls. The levels of 55 mature miRNAs significantly differed in serum exosomes from PCOS patients compared with those from normal controls. Real-time PCR was used to verify the expression of eight of these miRNAs, among which miR-27a-5p was the most significantly elevated in PCOS patients serum exosomes. The role of miR-27a-5p in EC migration and invasion was further investigated via miR-27a-5p mimics or inhibitor transfection in Ishikawa and HEC-1A EC cell lines. In addition, the SMAD4 gene was identified as the target of miR-27a-5p by several target prediction databases and was validated by a luciferase assay. SMAD4 mRNA and protein levels were downregulated in EC cells transfected with the miR-27a-5p mimics, but upregulated in cells transfected with the miR-27a-5p inhibitor. Furthermore, in vitro experiments results confirmed that miR-27a-5p prohibited migration and invasion via SMAD4 downregulation. Thus, serum exosomal miR-27a-5p may play a role in EC development in PCOS patients.

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Lena Espelage, Hadi Al-Hasani and Alexandra Chadt

The two closely related RabGAPs TBC1D1 and TBC1D4 are key signaling factors of skeletal muscle substrate utilization. In mice, deficiency in both RabGAPs leads to reduced skeletal muscle glucose transport in response to insulin and lower GLUT4 abundance. Conversely, Tbc1d1 and Tbc1d4 deficiency results in enhanced lipid use as fuel in skeletal muscle, through yet unknown mechanisms. In humans, variants in TBC1D1 and TBC1D4 are linked to obesity, insulin resistance and type 2 diabetes. While the specific function in metabolism of each of the two RabGAPs remains to be determined, TBC1D1 emerges to be controlling exercise endurance and physical capacity, whereas TBC1D4 may rather be responsible for maintaining muscle insulin sensitivity, muscle contraction, and exercise. There is growing evidence that TBC1D1 also plays an important role in skeletal muscle development, since it has been found to be associated to meat production traits in several livestock species. In addition, TBC1D1 protein abundance in skeletal muscle is regulated by both, insulin receptor and insulin-like growth factor-1 (IGF-1) receptor signaling. This review focuses on the specific roles of the two key signaling factors TBC1D1 and TBC1D4 in skeletal muscle metabolism, development and exercise physiology.

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Salman Azhar, Dachuan Dong, Wen-Jun Shen, Zhigang Hu and Fredric B Kraemer

miRNAs are endogenous noncoding single-stranded small RNAs of ~22 nucleotides in length that post-transcriptionally repress the expression of their various target genes. They contribute to the regulation of a variety of physiologic processes including embryonic development, differentiation and proliferation, apoptosis, metabolism, hemostasis and inflammation. In addition, aberrant miRNA expression is implicated in the pathogenesis of numerous diseases including cancer, hepatitis, cardiovascular diseases and metabolic diseases. Steroid hormones regulate virtually every aspect of metabolism, and acute and chronic steroid hormone biosynthesis is primarily regulated by tissue-specific trophic hormones involving transcriptional and translational events. In addition, it is becoming increasingly clear that steroidogenic pathways are also subject to post-transcriptional and post-translational regulations including processes such as phosphorylation/dephosphorylation, protein‒protein interactions and regulation by specific miRNAs, although the latter is in its infancy state. Here, we summarize the recent advances in miRNA-mediated regulation of steroidogenesis with emphasis on adrenal and gonadal steroidogenesis.

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Isadora C Furigo, Pryscila D S Teixeira, Paula G F Quaresma, Naira S Mansano, Renata Frazão and Jose Donato Jr

AgRP neurons are important players in the control of energy homeostasis and are responsive to several hormones. In addition, STAT5 signalling in the brain, which is activated by metabolic hormones and growth factors, modulates food intake, body fat and glucose homeostasis. Given that, and the absence of studies that describe STAT5 function in AgRP cells, the present study investigated the metabolic effects of Stat5a/b gene ablation in these neurons. We observed that STAT5 signalling in AgRP neurons regulates body fat in female mice. However, male and female STAT5-knockout mice did not exhibit altered food intake, energy expenditure or glucose homeostasis compared to control mice. The counter-regulatory response or glucoprivic hyperphagia induced by 2-deoxy-d-glucose treatment were also not affected by AgRP-specific STAT5 ablation. However, under 60% food restriction, AgRP STAT5-knockout mice had a blunted upregulation of hypothalamic Agrp mRNA expression and corticosterone serum levels compared to control mice, suggesting a possible role for STAT5 in AgRP neurons for neuroendocrine adaptations to food restriction. Interestingly, ad libitum fed knockout male mice had reduced Pomc and Ucp-1 mRNA expression compared to control group. Taken together, these results suggest that STAT5 signalling in AgRP neurons regulates body adiposity in female mice, as well as some neuroendocrine adaptations to food restriction.

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Francesco J. DeMayo and John Lydon

Progesterone’s ability to maintain pregnancy in eutherian mammals highlighted this steroid as the “hormone of pregnancy”. It was the unique “pro-gestational” bioactivity of progesterone that enabled eventual purification of this ovarian steroid to crystalline form by Willard Myron Allen in the early 1930s. While a functional connection between normal progesterone responses (“progestational proliferation”) of the uterus with the maintenance of pregnancy was quickly appreciated, an understanding of progesterone’s involvement in the early stages of pregnancy establishment was comparatively less well understood. With the aforementioned as historical backdrop, this review focusses on a selection of key advances in our understanding of the molecular mechanisms by which progesterone, through its nuclear receptor (the progesterone receptor), drives the development of endometrial receptivity, a transient uterine state that allows for embryo implantation and the establishment of pregnancy. Highlighted in this review are the significant contributions of advanced mouse engineering and genome-wide transcriptomic and cistromic analytics to revealing the pivotal molecular mediators and modifiers that are essential to progesterone-dependent endometrial receptivity and decidualization. With a clearer understanding of the molecular landscape that underpins uterine responsiveness to progesterone during the periimplantation period, we predict that common gynecologic morbidities due to abnormal progesterone responsiveness will be more effectively diagnosed and/or treated in the future.