Over-expression of calpastatin attenuates myocardial injury following myocardial infarction by inhibiting endoplasmic reticulum stress

Abstract

Background: Ischemic heart injury activates calpains and endoplasmic reticulum (ER) stress in cardiomyocytes. This study investigated whether over-expression of calpastatin, an endogenous calpain inhibitor, protects the heart against myocardial infarction (MI) by inhibiting ER stress. Methods: Mice over-expressing calpastatin (Tg-CAST) and littermate wild type (WT) mice were divided into four groups: WT-sham, Tg-CAST-sham, WT-MI, and Tg-CAST-MI, respectively. WT-sham and Tg-CAST-sham mice showed similar cardiac function at baseline. MI for 7 days impaired cardiac function in WT-MI mice, which was ameliorated in Tg-CAST-MI mice. Results: Tg-CAST-MI mice exhibited significantly decreased diameter of the left ventricular cavity, scar area, and cardiac cell death compared to WT-MI mice. WT-MI mice had higher cardiac expression of C/ EBP homologous protein (CHOP) and BIP, indicators of ER stress, compared to WT-sham mice, indicative of MI-induced ER stress. This increase was abolished in Tg-CAST-MI hearts. Furthermore, administration of tauroursodeoxycholic acid, an inhibitor of ER stress, reduced MI-induced expression of CHOP and BIP, scar area, and myocardial dysfunction. In an in vitro model of oxidative stress, H 2 O 2 stimulation of H9c2 cardiomyoblasts induced calpain activation, CHOP expression, and cell death, all of which were prevented by the calpain inhibitor PD150606, as well as CHOP silencing. Conclusions: Over-expression of calpastatin ameliorates MI-induced myocardial injury in mice. These protective effects of calpastatin are partially achieved through suppression of the ER stress/CHOP pathway.

Inhibition of Calpain Alleviates Apoptosis in Coxsackievirus B3-induced Acute Virus Myocarditis Through Suppressing Endoplasmic Reticulum Stress

“…Moreover, calpastatin overexpression attenuates myocardial injury in myocardial infarction by suppressing ER stress. 45) In the present study, we found inhibition calpain activity decreased CHOP levels, cleaved-Caspase-12, and p-JNK in VMC mice heart tissue. We also measured the protein of the upstream regulatory pathway of these proteins.…”

Tunicamycin-Induced Endoplasmic Reticulum Stress Damages Complex I in Cardiac Mitochondria

“…Activation of cytosolic CPN1 increases cell injury during cardiac ischemia-reperfusion [ 15 , 17 , 18 ]. Activation of mitochondria-localized CPN1 (mCPN1) contributes to mitochondrial damage during ischemia and reperfusion [ 19 , 20 , 21 , 22 , 23 ], diabetic cardiomyopathy [ 24 ], doxorubicin-induced cardiotoxicity [ 25 , 26 ], and heart failure [ 27 ]. Our previous study found that the induction of ER stress using thapsigargin led to mitochondrial dysfunction [ 13 ].…”

Cardiac abnormalities after induction of endoplasmic reticulum stress are associated with mitochondrial dysfunction and connexin43 expression

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