Regulation of (Pro) Renin Receptor Expression by Glucose-Induced Mitogen-Activated Protein Kinase, Nuclear Factor-κB, and Activator Protein-1 Signaling Pathways

Renal (pro) renin receptor (PRR) expression is increased in diabetes. The exact mechanisms involved in this process are not well established. We hypothesized that high glucose up-regulates PRR through protein kinase C (PKC)-Raf-ERK and PKC-c-Jun N-terminal kinase (JNK)-c-Jun signaling pathways. Rat mesangial cells exposed to 30 mM D-glucose demonstrated significant increase in PRR mRNA and protein expression, intracellular phosphorylation of Raf-1 (Y340/341), ERK, JNK, nuclear factor-kappa B (NF-kappa B) p65 (S536) and c-Jun (S63). By chromatin immunoprecipitation assay and EMSA, high glucose induced more functional NF-kappa B and activator protein (AP)-1 dimers bound to corresponding cis-regulatory elements in the predicted PRR promoter to up-regulate PRR transcription. Conventional and novel PKC inhibitors Chelerythrine and Rottlerin, Raf-1 inhibitor GW5074, MEK1/2 inhibitor U0126, JNK inhibitor SP600125, NF-kappa B inhibitor Quinazoline, and AP-1 inhibitor Curcumin, respectively, attenuated glucose-induced PRR up-regulation. Chelerythrine and Rottlerin also inhibited glucose-induced phosphorylation of Raf-1 (Y340/341), ERK1/2, JNK, NF-kappa B p65 (S536), and c-Jun (S63). GW5074 and U0126 inhibited the phosphorylation of ERK1/2 and NF-kappa B p65 (S536). SP600125 inhibited phosphorylation of NF-kappa B p65 (S536) and c-Jun (S63). We conclude that high glucose up-regulates the expression of PRR through mechanisms dependent on both PKC-Raf-ERK and PKC-JNK-c-Jun signaling pathways. NF-kappa B and AP-1 are involved in high-glucose-induced PRR up-regulation in rat mesangial cells. (Endocrinology 151: 3317-3325, 2010)