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Cardiac dysfunction is a major cause of multi-organ dysfunction in critical care units following severe burns. The purpose of this study was to investigate the role of inducible nitric oxide synthase (iNOS) in cardiac dysfunction in burned mice. Wild-type and iNOS-knockout mice were subjected to 30% total body surface area burns. Next, the expression of iNOS was measured at 1, 3 and 7 days post-burn. Cardiac function, insulin sensitivity, inflammation, oxidative stress, and apoptosis in the hearts of the mice were assessed at 3 days post-burn. Compared to control mice, iNOS expression was increased and reached a maximum in the heart of burned mice at 3 days post-burn. iNOS deficiency significantly alleviated the cardiac dysfunction and insulin resistance in burned mice. In addition, burn-induced inflammation, oxidative stress, and apoptosis in the heart were markedly reduced in iNOS-knockout burned mice when compared to corresponding values in wild-type burned mice. Our study demonstrates that iNOS contributes to insulin resistance in the hearts of mice following burn injury, and iNOS deficiency protects cardiac function against burn injury in mice, suggesting iNOS as a potential therapeutic target to treat burn injuries. [ABSTRACT FROM AUTHOR]

Progesterone exerts antihypertensive actions partially by modulating endothelial nitric oxide synthase (eNOS) activity. Here, we aimed to investigate the effects and mechanisms of progesterone on eNOS expression. First, human umbilical vein endothelial cells (HUVECs) were exposed to progesterone and then the eNOS transcription factor specificity protein-1 (SP-1) and progesterone receptor (PR A/B ) expression were assessed by Western blotting and qRT-PCR. The interaction between SP-1 and PR A/B was next determined through coimmunoprecipitation assay. The chromatin immunoprecipitation assay and luciferase assay were used to investigate the relationship of PR A/B , SP-1, and eNOS promoter. At last, rats were intraperitoneally injected with progesterone receptor antagonist RU-486, and then the expression of eNOS and vasodilation function in thoracic aorta and mesenteric artery were measured. The results showed that progesterone could increase eNOS expression in HUVECs. Further study showed that progesterone increased PR A -SP-1 complex formation and facilitated PR A/B and SP-1 binding to eNOS promoter. Mutating SP-1 or PR-binding motif on eNOS promoter abolished the effect of progesterone on eNOS gene transcription. We also observed that progesterone receptor antagonist RU-486 reduced eNOS expression and impaired vasodilation in rats. Those results suggest that progesterone modulates eNOS expression through promoting PR A -SP-1 complex formation, and progesterone antagonist attenuates eNOS expression, leading to the loss of vascular relaxation. NEW & NOTEWORTHY Progesterone directly upregulated endothelial nitric oxide synthase (eNOS) expression in human endothelial cells. Progesterone augmented eNOS promoter activity through a progesterone receptor A- and specificity protein-1-dependent manner. Antagonism of the progesterone receptor reduced eNOS expression and impaired vasodilation in rats.

Circular RNAs (circRNAs) are generated by head-to-tail splicing and are ubiquitously expressed in all multicellular organisms. Their important biological functions are increasingly recognized. Cerebral ischemia reperfusion injury-induced brain microvascular endothelial cell dysfunction is an initial stage of blood-brain barrier disruption. The expression profile and potential function of circRNAs in brain microvascular endothelial cells is unknown. Rat brain microvascular endothelial cells were extracted and cultured in glucose-free medium for 4 hours with 5% CO 2 and 95% N 2 , and the medium was then replaced with complete growth medium for 6 hours. The RNA in these cells was then extracted. The circRNA was identified by Find_circ and CIRI2 software. Functional and pathway enrichment analysis of genes that were common to differentially expressed mRNAs and circRNA host genes was performed by the Database for Annotation, Visualization and Integrated Discovery Functional Annotation Tool. Miranda software was used to predict microRNAs that were potentially spong-ed by circRNAs. Furthermore, cytoscape depicted the circR-NA-microRNA interaction network. The results showed that there were 1288 circRNAs in normal and oxygen-glucose deprived/recovered primary brain microvascular endothelial cells. There are 211 upregulated and 326 downregulated differentially expressed circRNAs. The host genes of these differentially expressed circRNAs overlapped with those of differentially expressed mRNAs. The shared genes were further studied by functional enrichment analyses, which revealed that circRNAs may contribute to calcium ion function and the cyclic guanosine 3',5'-monophosphate (CAMP) dependent protein kinase (PKα) signaling pathway. Next, quantitative reverse transcription polymerase chain reaction assays were performed to detect circRNA levels transcribed from the overlapping host genes. Eight out of the ten circRNAs with the highest fold-change identified by sequencing were successfully verified. Subsequently, the circRNA-microRNA interaction networks of these eight circRNAs were explored by bioinformatic analysis. These results demonstrate that altered circRNAs may be important in the pathogenesis of cerebral ischemia reperfusion injury and consequently may also be potential therapeutic targets for cerebral ischemia diseases. All animal experiments were approved by the Chongqing Medical University Committee on Animal Research, China (approval No. CQMU20180086) on March 22, 2018., Competing Interests: None