Several lines of evidence support the functional role of oxidative stress in the downregulation of Wnt pathway in A14, C2C12, OB-6, and/or HEK293 cells [11, 18, 60], other researchers, however, have an opposite notion that oxidative stress contributes to activation of the Wnt/β-catenin pathway and downstream Tcf signaling in L cells, NIH3T3 or HEK293 cells [61], endothelial cells [62], and a rat model of diabetic retinopathy [63, 64]. Here, HNF4A is linked to diabetic retinopathy.