Molecular mechanism underlying increased ischemic damage in the ALDH2*2 genetic polymorphism using a human iPSC model system

We investigated the ALDH2*2 genetic polymorphism and its underlying mechanisms for the first time in a human model system of induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) generated from individuals carrying the most common heterozygous form of the ALDH2*2 genotype. We showed that the ALDH2*2 mutation confers elevated levels of reactive oxygen species (ROS) and toxic aldehydes such as 4HNE, thereby inducing cell cycle arrest and activation of apoptotic signaling pathways, especially during ischemic injury. ALDH2 exerts control of cell survival decisions via modulation of oxidative stress levels. This regulatory circuitry was found to be dysfunctional in the loss-of-function ALDH2*2 genotype, causing upregulation of apoptosis in cardiomyocytes following ischemic insult. These results reveal a novel function of the metabolic enzyme ALDH2 in modulation of cell survival decisions. Overall design: Molecular mechanism of increased ischemic damage in cardiomyocytes of ALDH2*2 genotype.