PSME1 and cardiomyopathy: Because of the protective effects of PA28α overexpression upon cardiomyopathy and re‐oxygenation stress of the heart (Li, Horak, et al., 2011; Li, Powell, et al., 2011), we focused on heart, as well as hippocampus, for the further investigation of biochemical effects of PA28α overexpression during aging.