Circular RNA ZBTB46 depletion alleviates the progression of Atherosclerosis by regulating the ubiquitination and degradation of hnRNPA2B1 via the AKT/mTOR pathway

Background: CircZBTB46 has been identified as being associated with the risk of coronary artery disease (CAD) and has the potential to be a diagnostic biomarker for CAD. However, the specific function and detailed mechanism of circZBTB46 in CAD are still unknown.

Methods: The expression levels and properties of circRNAs were examined using qRT‒PCR, RNA FISH, and subcellular localization analysis. ApoE^-/- mice fed a high-fat diet were used to establish an atherosclerosis model. HE, Masson, and Oil Red O staining were used to analyze the morphological features of the plaque. CCK-8, Transwell, and wound healing assays, and flow cytometric analysis were used to evaluate cell proliferation, migration, and Apoptosis. RNA pull-down, silver staining, mass spectrometry analysis, and RNA-binding protein immunoprecipitation (RIP) were performed to identify the interacting proteins of circZBTB46.

Results: CircZBTB46 is highly conserved and is significantly upregulated in atherosclerotic lesions. Functional studies revealed that knockdown of circZBTB46 significantly decreased the atherosclerotic plaque area, attenuating the progression of atherosclerosis. In addition, silencing circZBTB46 inhibited cell proliferation and migration and induced Apoptosis. Mechanistically, circZBTB46 physically interacted with hnRNPA2B1 and suppressed its degradation, thereby regulating cell functions and the formation of aortic atherosclerotic plaques. Additionally, circZBTB46 was identified as a functional mediator of PTEN-dependent regulation of the Akt/mTOR signaling pathway and thus affected cell proliferation and migration and induced Apoptosis.

Conclusion: Our study provides the first direct evidence that circZBTB46 functions as an important regulatory molecule for CAD progression by interacting with hnRNPA2B1 and regulating the PTEN/Akt/mTOR pathway.

Atherosclerotic plaque; circular RNA; Coronary artery Disease; RNA-binding protein.