Hydrogen Peroxide Upregulates PLGF and VEGF‐A Expression in Primary Human Coronary Artery Smooth Muscle Cells

Abstract

When supply arteries become occluded a compensatory mechanism termed arteriogenesis occurs, resulting in collateral artery enlargement. Arteriogenesis involves attachment of monocytes to the endothelium and subsequent vessel wall infiltration. Placental growth factor (PLGF) mediates components of this collateral remodeling process. Our lab previously showed that hydrogen peroxide (H2O2) significantly upregulates PLGF mRNA expression in A10 cells, an established smooth muscle cell (SMC) line derived from rat aorta. Since SMC undergo phenotypic changes in culture, the goal of this study was to determine whether PLGF is also regulated by H2O2 in a more physiological model (primary SMC). Primary human coronary artery SMC (CASMC, Lonza) were grown to ~80% confluence, then serum‐starved (1% FBS) for 48 hrs. CASMC were then treated with exogenous H2O2 (50 μM) (N=3) for 4 hrs. PLGF and VEGF‐A gene expression was analyzed by real time quantitative PCR (Q‐PCR). PLGF gene expression was increased ~3.5 fold (p<0.05) in CASMC by H2O2 treatment, compared with untreated CASMC (N=3). VEGF gene expression increased ~6 fold (p<0.05) in response to H2O2. We conclude that H2O2 regulates PLGF and VEGF expression in primary SMC, confirming the physiological relevance of this mechanism. Further experiments to characterize protein levels of PLGF, VEGF, and PLGF/VEGF dimeric forms are underway. Support: NIH R01 HL‐084494 (PL).