Proteomic and Metabolomic Analysis of Vascular Smooth Muscle Cells

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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 PKCδ-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 PKCδ+/+ and PKCδ−/− mice. Using 2-dimensional electrophoresis and mass spectrometry, we identified >30 protein species that were altered in PKCδ−/− 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 PKCδ−/− SMCs, which were associated with a significant increase in cellular glutathione levels resulting in resistance to cell death induced by oxidative stress. Furthermore, PKCδ−/− SMCs overexpressed RhoGDIα, 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 PKCδ is crucial in regulating glucose and lipid metabolism, controlling the cellular redox state, and maintaining SMC differentiation.