SOD1 and diabetic cardiomyopathy: DCM, diabetic cardiomyopathy; ERK, extracellular signal-regulated kinase; GLUT4, glucose transporter type 4; HSP, heat shock protein; MiR, miRNA, microRNA; MSC, mesenchymal stem cell; Mst1, mammalian sterile 20-like kinase 1; p-Akt, phosphorylated protein kinase B; SOD1, superoxide dismutase 1.