CTRP3 alleviates myocardial ischemia/reperfusion injury in mice through activating LAMP1/JIP2/JNK pathway

Myocardial ischemia reperfusion (I/R) injury is an important complication of myocardial infarction reperfusion therapy, and no effective treatment has been identified. Based on preexisting evidence, C1q/tumor necrosis factor-related protein 3 (CTRP3) has been reported to be closely associated with myocardial dysfunction. In this study, we found that CTRP3 was downregulated in acute coronary syndrome (ACS) patients and myocardial I/R mice. Silence of CTRP3 aggravated cardiac systolic function due to I/R of mice, while CTRP3 overexpression ameliorated cardiac function. Moreover, overexpression of CTRP3 improved I/R inhibitory effects on the levels of creatinine phosphokinase (CPK), lactate dehydrogenase (LDH) and cardiac troponin-I (cTn-I), myocardial infarction area, the intensity of the 3-nitrotyrosine (3-NT), apoptosis and protein levels of LAMP1, JNK-Interacting Protein-2 (JIP-2) and JNK, while these effects could be exacerbated by downregulation of CTRP3. Co-IP experiments could identify physical interactions between CTRP3 and lysosomal-associated membrane protein 1 (LAMP1) and Numb and JIP2. LAMP1 silence aggravated the inhibition effects of I/R on JIP2 and JNK protein expression, CPK, LDH and cTn-I levels and caspase-3 activity, while overexpression of LAMP1 recovered these inhibition effects of I/R. JNK inhibitor (SP600125) could reverse the inhibitory effects of CTRP3 overexpression on CPK, LDH, cTn-I, myocardial infarction, strong positive staining for 3-NT and apoptosis. These findings demonstrated that CTRP3 protected against injury caused by myocardial I/R through activating LAMP1/JIP2/JNK pathway to attenuate myocardial injury, improve left ventricular function, decrease myocardial infarction, and reduce myocardial apoptosis.