Proteomic and metabolomic analysis of vascular smooth muscle cells: role of PKCdelta

Abstract

Recent developments of proteomic and metabolomic techniques provide powerful tools for studying molecular mechanisms of cell function. Previously, we demonstrated that neointima formation was markedly increased in vein grafts of PKCdelta-deficient mice compared with wild-type controls. To clarify the underlying mechanism, we performed a proteomic and metabolomic analysis of cultured vascular smooth muscle cells (SMCs) derived from PKCdelta+/+ and PKCdelta-/- mice. Using 2-dimensional electrophoresis and mass spectrometry, we identified >30 protein species that were altered in PKCdelta-/- SMCs, including enzymes related to glucose and lipid metabolism, glutathione recycling, chaperones, and cytoskeletal proteins. Interestingly, nuclear magnetic resonance spectroscopy confirmed marked changes in glucose metabolism in PKCdelta-/- SMCs, which were associated with a significant increase in cellular glutathione levels resulting in resistance to cell death induced by oxidative stress. Furthermore, PKCdelta-/- SMCs overexpressed RhoGDIalpha, an endogenous inhibitor of Rho signaling pathways. Inhibition of Rho signaling was associated with a loss of stress fiber formation and decreased expression of SMC differentiation markers. Thus, we performed the first combined proteomic and metabolomic study in vascular SMCs and demonstrate that PKCdelta is crucial in regulating glucose and lipid metabolism, controlling the cellular redox state, and maintaining SMC differentiation.