Excessive AGEs in diabetes promote the upregulation of copper importer solute carrier family 31 member 1 through activating transcription factor 3/transcription factor PU.1, thereby increasing intracellular Cu+ accumulation in cardiomyocytes and disturbing Cu+ homeostasis, leading to a decline of Fe–S cluster protein and reactive oxygen species accumulation in cardiomyocytes mitochondria. The gene discussed is TCF3; the disease is diabetes mellitus.