Serum Extracellular Vesicles Attenuate Cardiomyocyte Injury Induced by Hypoxic/Reoxygenation by Regulating miR-1229-5p.

Ischemic heart disease and the resulting heart failure remain the leading causes of death and disability worldwide. This study aimed to investigate the role of miR-1229-5p in serum extracellular vesicles (EVs) mediated myocardial protection by constructing a hypoxia/reoxygenation model (HR) in H9c2 cells. Cardiomyocytes were cultured and divided into different treatment groups: control group, HR group, serum-EVs group, and serum-EVs + miR-1229-5p inhibitor group. The expression levels of miR-1229-5p were detected using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The changes in cell proliferation and apoptosis were detected by MTT assay and flow cytometry. The myocardial injury-related indicators, cardiac troponin I (cTnI), creatinine kinase MB (CK-MB), and lactate dehydrogenase (LDH), were measured by enzyme-linked immunosorbent assay (ELISA). Finally, the luciferase reporter assay was used to verify the miR-1229-5p target. The proliferation of myocardial cells in the HR group was reduced, the number of apoptotic cells was increased, and myocardial injury indicators concentration was decreased. Transfection of miR-1229-5p inhibitor under serum-EVs treatment reduced the protective effect of serum-EVs on myocardial cell injury, decreased cell proliferation, increased the number of apoptotic cells, and increased myocardial injury indicator concentration. Additionally, FOXO4 may be the target of miR-1229-5p. Our data suggest that serum-EVs alleviate HR-induced cardiomyocyte injury by regulating miR-1229-5p/FOXO4.

Long non-coding RNA LINC00299 knockdown inhibits ox-LDL-induced T/G HA-VSMC injury by regulating miR-135a-5p/XBP1 axis in atherosclerosis.

BACKGROUND: Atherosclerosis (AS) is a highly relevant social problem. Long non-coding RNA (lncRNA) long intergenic non-coding00299 (LINC00299) participates in the regulation of AS development. Therefore, this study was to explore the potential role and mechanism of LINC00299 in AS. METHODS: Human aortic vascular smooth muscle cells (T/G HA-VSMCs) were treated with oxidized low-density lipoprotein (ox-LDL). Cell viability and migration were measured by 3-(4, 5-dimethyl-2-thiazolyl)-2, 5-diphenyl-2-H-tetrazolium bromide (MTT) and transwell assays, severally. The activities of SOD and MDA were detected by total superoxide dismutase assay kit and malondialdehyde assay kit. The protein levels of ki67, matrix metalloproteinase 9 (MMP9) and X-box binding protein 1 (XBP1) were detected by western blot assay. The expression levels of LINC00299, microRNA-135a-5p (miR-135a-5p) and XBP1 were detected by real-time quantitative polymerase chain reaction (RT-qPCR). The binding relationship between miR-135a-5p and LINC00299 or XBP1 was predicted by miRcode and Starbase3.0 then verified by the dual-luciferase reporter assay. RESULTS: Ox-LDL induced cell viability, oxidative damage and migration of T/G HA-VSMCs. LINC00299 knockdown weakened ox-LDL-induced T/G HA-VSMCs injury. Mechanical analysis confirmed that LINC00299 improved XBP1 expression by interacting with miR-135a-5p. Furthermore, rescue assays showed that LINC00299 regulated ox-LDL-induced T/G HA-VSMCs injury through the miR-135a-5p/XBP1 axis. CONCLUSIONS: Our studies revealed the regulatory function of LINC00299/miR-135a-5p/XBP1 axis in AS development, suggesting a potential therapeutic strategy for AS treatment.