RBPJ and Hyperglycemia: NRG1 protein levels were also consistently lower in ΔE-250 and ΔE-Rbpj cells treated with HG compared with wild-type cells (Fig. 5b), indicating that the Nrg1 enhancer plays a crucial role in hyperglycemia-induced Nrg1 expression and functions at least in part through Rbpj.