DDIT4 and diabetes mellitus: TXNIP inhibits thioredoxin antioxidant function by binding to its redox-active cysteine residues.44 In both REDD1−/− and TXNIP−/− cells, thioredoxin activity is elevated and ROS levels are reduced.19 In REDD1−/− cells, increased TXNIP expression was insufficient to increase ROS levels.19 With regard to DR, TXNIP expression is upregulated in the retina of diabetic mice, and TXNIP knockdown is sufficient to reduce diabetes-induced retinal pathology.45