Inhibition of protein O-GlcNAcylation dramatically reduces Cx43 expression and glial activation induced by hyperglycemia [70], indicating that O-GlcNAcylation of certain key proteins may contribute to the development of DR despite the fact that they are fundamentally insusceptible to cellular O-GlcNAcylation levels. Here, GJA1 is linked to Hyperglycemia.