Long Non-Coding RNA SOX2 Overlapping Transcript Aggravates H9c2 Cell Injury via the miR-215-5p/ZEB2 Axis and Promotes Ischemic Heart Failure in a Rat Model

Heart failure is a common cardiovascular disease, which has been regarded as one of the highest health care costs with high morbidity and mortality in the western countries. Long noncoding RNAs have been widely reported to regulate the initiation or progression of cardiovascular diseases. However, the specific role of SOX2 overlapping transcript (SOX2-OT) in ischemic heart failure remains uncharacterized. The present study aimed to explore the function and mechanism of SOX2-OT in ischemic heart failure. The starBase website was used to predict potential miRNAs or target mRNAs. Western blot assay was implemented to test collagen protein levels. Functional assays were conducted to evaluate the effects of SOX2-OT on H9c2 cell viability and apoptosis. RNA pull down and luciferase reporter assays were used to confirm the combination between miR-215-5p and SOX2-OT. We found out that SOX2-OT level was increased by oxygen glucose deprivation/reoxygenation treatment in H9c2 cells. Silencing of SOX2-OT ameliorated cell injury by promoting cell viability, inhibiting cell apoptosis and reducing productions of collagens. Mechanistically, miR-215-5p was confirmed to bind with SOX2-OT after prediction and screening. In addition, we discovered that miR-215-5p negatively regulated zinc finger E-box binding homeobox 2 (ZEB2) protein level by directly binding with ZEB2 3' untranslated region. Finally, we verified that SOX2-OT aggravated cell injury by targeting ZEB2 in H9c2 cells. In conclusion, SOX2-OT aggravated heart failure in vivo and promoted H9c2 cell injury via the miR-215-5p/ZEB2 axis in vitro, implying a novel insight into heart failure treatment.