Thioredoxin reductases are selenoproteins that are critical for maintaining cellular redox balance and eliminating reactive oxygen species (ROS) (1-4). There are three known mammalian thioredoxin reductases: TRXR1/TXNRD1 (cytosolic), TRXR2/TXNRD2 (mitochondrial), and TRXR3/TXNRD3 (testis-specific) (1). TRXR2