Mechanism of mTOR/RILP-regulated autophagic flux in increased susceptibility to myocardial ischemia-reperfusion in diabetic mice.

Abstract

Background: The increased myocardial vulnerability that occurs in diabetic patients following an ischemia-reperfusion injury (I/RI) represents a significant perioperative safety risk. A comprehensive understanding of the intrinsic mechanisms underlying this phenomenon is therefore of paramount importance.

Purposes: The objective of this study is to investigate the potential mechanism of action between impaired autophagic flux and increased vulnerability in diabetic myocardium. This will provide a foundation for the clinical search for effective preventive and curative measures.

Methods: The transcriptomic alterations in autophagy-related genes following myocardial exposure to I/RI were analyzed by single-cell sequencing. This was followed by the validation of potential mechanisms of action between impaired autophagic flux and increased susceptibility at the cellular and animal levels, respectively.

Results: After I/RI in diabetic myocardium, there was a significant increase in the number of CM1 subgroups and a specific downregulation of 239 autophagy-related genes led by RILP. HE staining revealed that myocardial injury was exacerbated in diabetic mice subjected to I/RI. Transmission electron microscopy revealed that the accumulation of autophagic vesicles in cardiomyocytes of diabetic mice resulted in impaired autophagic flux. qRT-PCR revealed that the expression of RILP was significantly reduced in diabetic mice subjected to I/RI. WB showed that P62 was significantly increased and RILP was significantly decreased in diabetic mice subjected to I/RI compared to healthy mice. Inhibition of mTOR during hypoxia/reoxygenation (H/R) injury restored RILP expression and attenuated cellular injury in cardiomyocytes cultured with high glucose.

Conclusion: Following I/RI in diabetic myocardium, an increase in the CM1 subpopulation and a reduction in RILP expression result in impaired autophagic flux. Regulation of the mTOR/RILP pathway can restore impaired autophagic flux and improve myocardial vulnerability, thereby exerting cardioprotective effects.