Analysis of proteome and transcriptome of tumor necrosis factor α stimulated vascular smooth muscle cells with or without alpha lipoic acid

Abstract

Vascular smooth muscle cells (VSMCs) play an important role in the development and progression of atherosclerosis. Tumor necrosis factor α (TNFα), a cytokine secreted by VSMCs and macrophages in atherosclerotic lesions, regulates a variety of cellular functions of inflammatory cells and VSMCs by promoting cell growth and motility, which are critical for the initiation and progression of vascularlesions. Alpha lipoic acid (ALA), a well known antioxidant, acts as a pyruvate dehydrogenase cofactor in mitochondrial metabolism. Recently, we reported that ALA has many beneficial effects on vascular cells in atherosclerosis. The aim of the current study was to examine VSMCs, treated for 24 hours with TNFα (10 ng/mL) in the presence or absence of ALA (2 mM), for differential protein and genes expression using two-dimensional gel electrophoresis (2-DE) and DNA microarray analysis, respectively. Using 2-DE, we identified proteins whose expression changed by at least 2.5-fold after TNFα stimulation. Proteins up-regulated by TNFα that were subsequently down-regulated in the presence of ALA were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry as plasminogen activator inhibitor-2, fetal liver LKB-interacting protein, osteoblast-specific factor 2, glucosidase II, cyclin-dependent kinase 3, endoplasmin precursor and glutathione synthetase. TNFα down-regulated proteins that were up-regulated in the presence of ALA were keratin 19, eukaryotic translation elongation factor and Rho GDP dissociation inhibitor α. Gene expression analysis using DNA microarray tools confirmed the up-regulation or down-regulation of some, but not all, of the proteins observed in ALA challenged, TNFα-treated cells. This data should provide valuable information about the underlying mechanisms of atherosclerosis. Keywords: Alpha lipoic acid / Microarray / Tumor necrosis factor a / Two-dimensional gel electrophoresis / Vascular smooth muscle cell