BuyangHuanwu Decoction alleviates Endothelial Cell Apoptosis and Coronary Microvascular Dysfunction via Regulation of the MAPKK4/p38 Signaling Axis

MAPKK4 has been implicated in the pathological processes driving myocardial and vascular injury, particularly by influencing endothelial cell damage and apoptosis through various intracellular pathways. However, its regulatory role in coronary microvascular injury following myocardial infarction remains unclear, and the potential of mitochondrial-targeted therapeutic agents is yet to be explored. To address this, we developed a MAPKK4 gene-modified mouse model of ischemia-reperfusion (I/R) injury and tested the efficacy of Buyang Huanwu Decoction (BYHW), a traditional cardiovascular remedy, in alleviating coronary microvascular injury caused by I/R. This study aimed to clarify how BYHW mitigates coronary microvascular injury through the inhibition of endothelial cell apoptosis.

Our results showed that high doses of BYHW significantly improved coronary microvascular injury post-I/R by restoring microvascular integrity and reducing inflammation and oxidative stress. However, in MAPKK4-overexpressing transgenic mice, BYHW treatment failed to reduce microvascular inflammation and oxidative stress. To investigate further, we simulated hypoxia/reoxygenation injury in vascular endothelial cells using a MAPKK4-modified cellular model. The findings revealed that BYHW mitigated inflammatory damage and enhanced the viability of vascular endothelial cells following hypoxia, suppressing apoptosis through the mitochondrial pathway. Notably, overexpression of the MAPKK4/P38 axis nullified these therapeutic benefits, with BYHW showing no reduction in apoptosis or oxidative stress under hypoxic conditions.

Molecular interaction studies confirmed that key active components of PIM447 BYHW, Astragaloside IV and Ligustrazine, interact with the MAPKK4/P38 pathway. In vitro experiments further highlighted the crucial role of the MAPKK4-P38 interaction in regulating BYHW’s anti-apoptotic effects on coronary microvascular endothelial cells. Therapeutically, MAPKK4 may promote apoptosis in these cells by modulating P38 expression and phosphorylation, thereby aggravating coronary microvascular injury during ischemia-reperfusion. In vivo, overexpression of MAPKK4 and P38 blocked the protective effects of BYHW on the coronary microvasculature.

These findings underscore the pivotal role of the MAPKK4-P38 axis in regulating endothelial cell apoptosis and highlight the importance of targeting this pathway to enhance coronary microvascular protection in ischemia-reperfusion injury.