Diazoxide Post-conditioning Activates the HIF-1/HRE Pathway to Induce Myocardial Protection in Hypoxic/Reoxygenated Cardiomyocytes

Abstract

Background: Previous studies have shown that diazoxide can protect against myocardial ischemia-reperfusion injury (MIRI). The intranuclear hypoxia-inducible factor-1 (HIF-1)/hypoxia-response element (HRE) pathway has been shown to withstand cellular damage caused by MIRI. It remains unclear whether diazoxide post-conditioning is correlated with the HIF-1/HRE pathway in protective effect on cardiomyocytes.Methods: An isolated cardiomyocyte model of hypoxia-reoxygenation injury was established. Prior to reoxygenation, cardiomyocytes underwent post-conditioning treatment by diazoxide, and 5-hydroxydecanoate (5-HD), N-(2-mercaptopropionyl)-glycine (MPG), or dimethyloxallyl glycine (DMOG) followed by diazoxide. At the end of reoxygenation, ultrastructural morphology; mitochondrial membrane potential; interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), reactive oxygen species (ROS), and HIF-1α levels; and downstream gene mRNA and protein levels were analyzed to elucidate the protective mechanism of diazoxide post-conditioning.Results: Diazoxide post-conditioning enabled activation of the HIF-1/HRE pathway to induce myocardial protection. When the mitoKATP channel was inhibited and ROS cleared, the diazoxide effect was eliminated. DMOG was able to reverse the effect of ROS absence to restore the diazoxide effect. MitoKATP and ROS in the early reoxygenation phase were key to activation of the HIF-1/HRE pathway.Conclusion: Diazoxide post-conditioning promotes opening of the mitoKATP channel to generate a moderate ROS level that activates the HIF-1/HRE pathway and subsequently induces myocardial protection.

Metabolomics analysis in rat hearts with ischemia/reperfusion injury after diazoxide postconditioning

“…In this study, diazoxide postconditioning was found to significantly reduce myocardial ischemia-reperfusion injury, which is consistent with our previous results ( Cao et al, 2015 ; Pan et al, 2020 ; Chen et al, 2021 ). The present study indicated that MIRI disturbed multiple metabolic changes, including decreased levels of citrate, nicotinate, L-threonine, and L-lysine.…”

“…Evidence indicates that inhibiting SDH reduces the content of succinate and ROS production, thus protecting cardiac function from MIRI ( Valls-Lacalle et al, 2018 ; Xu et al, 2018 ). Our previous result showed that diazoxide postconditioning can decrease ROS level ( Chen et al, 2021 ). This study showed that the level of succinate decreased after diazoxide postconditioning, which may be involved in inhibiting SDH ( Anastacio et al, 2013 ).…”

“…Diazoxide is a specific opener of the mitoKATP channel. Studies have found that diazoxide can attenuate MIRI ( Onukwufor et al, 2016 ; Jin et al, 2020 ; Chen et al, 2021 ). However, the exact modulation mechanism for alleviating MIRI has not been clearly illustrated.…”

Bioinformatics integration reveals key genes associated with mitophagy in myocardial ischemia-reperfusion injury

“…Furthermore, the HIF-1α/BNIP3-mediated regulation of mitophagy that we have discovered provides new insights into potential therapeutic targets for myocardial ischemia–reperfusion injury [ 69 ]. A growing body of scholars has begun to direct their attention towards the role of autophagy in myocardial protection, holding the promise of unveiling novel therapeutic strategies for MIRI [ 70 ].…”