Dynamic localization and functional implications of C-peptide might for suppression of iNOS in high glucose-stimulated rat mesangial cells.

Although C-peptide has unique beneficial effects on diabetic nephropathy (DN), its functional localization and molecular mechanism have not been fully clarified. Whether C-peptide exhibits its protective role through the regulation of inducible nitric oxide synthase (iNOS), a key enzyme in oxidative stress, is not clear. In this study, it was revealed that C-peptide could enter the nucleus of high glucose-stimulated mesangial cells, especially in a time-dependent manner by high glucose pretreatment, while no C-peptide was detected in low glucose-cultured mesangial cells. The dynamic functional localization of C-peptide might be the intrinsic cause of its unique beneficial effects for DN, which may provide a foundation for further clarification of its underlying mechanism. Our preliminarily data also shown C-peptide suppressed the iNOS expression. Taking together, these results revealed the dynamic functional localization of C-peptide by high glucose stimulation in rat mesangial cells, which might suppress expression of iNOS to exhibit its protective effects.