Adiponectin secreted from adipose tissues plays a role in the regulation of energy homeostasis, food intake, and reproduction in the hypothalamus. We have previously demonstrated that adiponectin significantly inhibited GNRH secretion from GT1-7 hypothalamic GNRH neuron cells. In this study, we further investigated the effect of adiponectin on hypothalamicKISS1gene transcription, which is the upstream signal of GNRH. We found that globular adiponectin (gAd) or AICAR, an artificial AMPK activator, decreasedKISS1mRNA transcription and promoter activity. Conversely, inhibition of AMPK by Compound C or AMPKα1-SiRNA augmentedKISS1mRNA transcription and promoter activity. Additionally, gAd and AICAR decreased the translocation of specificity protein-1 (SP1) from cytoplasm to nucleus; however, Compound C and AMPKα1-siRNA played an inverse role. Our experimentsin vivodemonstrated that the expression ofKiss1mRNA was stimulated twofold in the Compound C-treated rats and decreased about 60–70% in gAd- or AICAR-treated rats compared with control group. The numbers of kisspeptin immunopositive neurons in the arcuate nucleus region of Sprague Dawley rats mimicked the same trend seen inKiss1mRNA levels in animal groups with different treatments. In conclusion, our results provide the first evidence that adiponectin reducesKiss1gene transcription in GT1-7 cells through activation of AMPK and subsequently decreased translocation of SP1.

Background: Obstructive sleep apnea hypopnea syndrome (OSAHS) is a contributing factor for non-alcoholic fatty liver disease (NAFLD). Non-invasive algorithms including fatty liver index (FLI) and hepatic steatosis index (HSI) have been used as a screening test for NAFLD in epidemiologic studies. The aim of this study is to compare the diagnostic accuracy of FLI and HSI for NAFLD detection in adults with OSAHS. Methods: We enrolled consecutive adult subjects who were newly diagnosed with OSAHS from March 2016 to January 2018. NAFLD was diagnosed by ultrasonography. The accuracy and cut-off point of the FLI and HSI to detect NAFLD were assessed by analyzing the area under the receiver operating characteristic (AUROC) curve and the maximum Youden index analysis, respectively. Results: The 326 subjects were diagnosed as NAFLD according to ultrasound findings, while 105 subjects who had normal abdominal ultrasonography were grouped as controls. Both FLI and HSI values were significantly higher in patients with NAFLD compared with controls. The AUROC of FLI and HSI for predicting NAFLD was 0.802 (95% confidence interval [CI] 0.762–0.839) and 0.753 (95% CI 0.710–0.793), respectively. The AUROC of FLI was significantly higher than that of HSI (P = 0.0383). The optimal cut-off value of FLI and HSI was 60 (sensitivity 66% and specificity 80%) and 35 (sensitivity 81% and specificity 60%), respectively. Conclusions: Both FLI and HSI can serve as screening tools for NAFLD in OSAHS adults. The FLI shows better performance in diagnosing NAFLD than HSI. Trial registration: Chinese Clinical Trial Registry (No. ChiCTR-OOB-15007253), http://www.chictr.org.cn/showproj.aspx?proj=11606 .

MicroRNAs (miRNAs) have emerged as key modulators in the pathophysiologic processes of cardiovascular diseases. However, its function in cardiac injury induced by obstructive sleep apnea (OSA) remains unknown. The aim of the current study was to identify the effect and potential molecular mechanism of miR-146a-5p in intermittent hypoxia(IH)- induced myocardial damage. We exposed H9c2 cells to IH condition; the expression levels of miR-146a-5p were detected by RT-qPCR. Cell viability, cell apoptosis, and the expressions of apoptosis-associated proteins were assessed via Cell Counting Kit-8 (CCK-8), flow cytometry, and western blotting, respectively. Target genes of miR-146a-5p were confirmed by dual-luciferase reporter assay. IH remarkably lowered viability but enhanced cell apoptosis. Concomitantly, the miR-146a-5p expression level was increased in H9c2 cells after IH. Subsequent experiments showed that IH-induced injury was alleviated through miR-146a-5p silence. X-linked inhibitor of apoptosis protein (XIAP) was predicted by bioinformatics analysis and further confirmed as a direct target gene of miR-146a-5p. Surprisingly, the effect of miR-146a-5p inhibition under IH may be reversed by downregulating XIAP expression. In conclusion, our results demonstrated that miR-146a-5p could attenuate viability and promote the apoptosis of H9c2 by targeting XIAP, thus aggravating the H9c2 cell injury induced by IH, which could enhance our understanding of the mechanisms for OSA-associated cardiac injury.

Circular RNAs (circRNAs) participate in the development of various kinds of diseases. However, the function and roles of circRNAs in obstructive sleep apnea (OSA)-induced cardiovascular disease remain poorly understood. Therefore, we sought to explore the circRNA expression profiles and predict their functions in OSA-induced cardiac injury with the use of bioinformatics analysis. The model of OSA was established in mouse treated by chronic intermittent hypoxia (CIH) exposure. Then, we screened the circRNA profile using circRNA microarray. By comparing circRNA expression in three matched pairs of CIH-treated cardiac tissues and controls, differentially expressed circRNAs were identified in the CIH groups. Comparison of the selected circRNAs expression levels was performed between qRT-PCR and microarray. Meanwhile, we employed Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses to predict the functions of these selected circRNAs. Finally, we constructed a circRNA-miRNA-mRNA network based on the target prediction. It was found that a total of 124 circRNAs were differentially expressed in CIH-treated cardiac tissues (p ≤ 0.05, fold-change ≥ 1.5). Among them, 23 circRNAs were significantly down-regulated, and the other 101 were up-regulated. Then, ten circRNAs were randomly selected to validate the reliability of the microarray results by using qRT-PCR. Next, we conducted the GO and KEGG pathway analysis to explore the parental genes functions of differentially expressed circRNA. Finally, two significantly differentially expressed circRNAs (mmu_circRNA_014309 and mmu_circRNA_21856) were further selected to create a circRNA-miRNA-mRNA regulation network. Our study did first reveal that the differentially expressed circRNAs played a vital role in the pathogenesis of OSA-induced cardiac damage. Thus, our findings bring us closer to unraveling the pathophysiologic mechanisms and eliciting novel therapeutic targets for the treatment of OSA-associated cardiovascular diseases.