대기 미세먼지로 인한 혈관평활근세포 이동 기전 규명

Abstract

Vascular smooth muscle cells (VSMCs) proliferate and migrate in response to various forms of stress such as mechanical trauma, inflammation, growth factors, oxidative stress and alterations in blood pressure or flow. Clinical disorders that are characterized by VSMCs proliferation, migration, and the consequent neointima formation include atherosclerosis, posttransplant vasculopathy, and restenosis after balloon angioplasty. Ambient particulate matter (PM) is nowadays recognized as having major impacts on the cardiovascular system. Growing evidence suggests that long-term exposure to fine particulate matter (PM2.5) air pollution contributes to the risk of cardiovascular disease (CVD) morbidity and mortality. We examined the effects of PM on the VSMCs migration in an urban area of Seoul, Korea, and investigated the molecular mechanisms that are involved. The VSMCs were isolated from rat aorta and exposed to SS1 (summer season PM) and SW1 (winter season PM) in different concentration. Cell migration was assessed by boyden chamber assay and ROS generation was detected by confocal microscopy using the indicator H2DCF-DA. Expression of MMP (Matrix metalloproteinase) and activation of Akt, ERK1/2and p-65 (NF-κB) were evaluated by Western blot analysis. SS1 and SW1 significantly increased cell migration and ROS generation. Protein levels of MMP2 and MMP9 were increased in a concentration-dependent manner as compared to the control. The activation of p-65 (NF-κB) was increased but not the activation of Akt and ERK1/2. The involvement of MMP2 and MMP9 expression, and Akt, ERK1/2 and NF-κB activation in the responses was determined by western blot assay for their corresponding proteins using ROS scavenger N-acetylcysteine (NAC). NAC (2mM) decreased only the SS1 and SW1-induced intracellular ROS generation but not MMP2 and MMP9 expressions, and Akt and ERK activation. However, NF-κB activation was increased. In conclusion, the present data demonstrated that nontoxic-dose SS1 and SW1 induces cell migration and ROS generation in VSMCs. This result suggests the possibility that the refined study would be needed for each component of the SS1 and SW1 for the identification of specific signaling pathways.