Fig. 6.
Activation of the calcium/MCU/mPTP pathway abolishes SERCA-mediated endothelial protection in vivo. C57BL/6J mice received AAV9 SERCA (SERCAAAV9 group) or control AAV9 vectors (control group) before I/R injury. An I/R injury model was induced through 45 min of ischemia and 4 h of reperfusion. Animals in the sham group underwent all surgical procedures for I/R induction except the ligation step. To induce intracellular calcium overload, a single intraperitoneal (i.p.) injection of ionomycin at 1 mg/kg was given 30 min before the I/R model. In addition, to activate MCU in SERCAAAV9 mice, spermine i.p. treatment at 5 mg/kg was given 60 min before I/R surgery. A. Cardiac microcirculation was observed using an electron microscope (EM). B–D. Proteins were isolated from reperfused hearts, and then the levels of phosphorylated eNOS and ET-1 were measured through western blots. E–F. RNA was isolated from reperfused hearts, and the transcriptions of MCP1 and IL-1 were determined through qPCR. G. A schematic summary of our findings. Overexpression of SERCA attenuates the burden of intracellular calcium and thus inhibits MCU activation, resulting in the closure of mPTP and necroptosis inhibition. *p < .05.