LDL-Induced Impairment of Human Vascular Smooth Muscle Cells Repair Function Is Reversed by HMG-CoA Reductase Inhibition Teresa Padro´ 1,2, Roberta Lugano1,2,3, Maisa Garcı´a-Arguinzonis1,2,3, Lina Badimon1,2,3,4* 1 Cardiovascular Research Center (CSIC-ICCC), Barcelona, Spain, 2 Biomedical Research Institute Sant-Pau (IIB-Sant Pau), Barcelona, Spain, 3 CiberOBN, Institute Carlos III, Barcelona, Spain, 4 Autonomous University of Barcelona, Barcelona, Spain Abstract Growing human atherosclerotic plaques show a progressive loss of vascular smooth muscle cells (VSMC) becoming soft and vulnerable. Lipid loaded-VSMC show impaired vascular repair function and motility due to changes in cytoskeleton proteins involved in cell-migration. Clinical benefits of statins reducing coronary events have been related to repopulation of vulnerable plaques with VSMC. Here, we investigated whether HMG-CoA reductase inhibition with rosuvastatin can reverse the effects induced by atherogenic concentrations of LDL either in the native (nLDL) form or modified by aggregation (agLDL) on human VSMC motility. Using a model of wound repair, we showed that treatment of human coronary VSMC with rosuvastatin significantly prevented (and reversed) the inhibitory effect of nLDL and agLDL in the repair of the cell depleted areas. In addition, rosuvastatin significantly abolished the agLDL-induced dephosphorylation of myosin regulatory light chain as demonstrated by 2DE-electrophoresis and mass spectrometry. Besides, confocal microscopy showed that rosuvastatin enhances actin-cytoskeleton reorganization during lipid-loaded-VSMC attachment and spreading. The effects of rosuvastatin on actin-cytoskeleton dynamics and cell migration were dependent on ROCK-signalling. Furthermore, rosuvastatin caused a significant increase in RhoA-GTP in the cytosol of VSMC. Taken together, our study demonstrated that inhibition of HMG-CoA reductase restores the migratory capacity and repair function of VSMC that is impaired by native and aggregated LDL. This mechanism may contribute to the stabilization of lipid-rich atherosclerotic plaques afforded by statins. Citation: Padro´ T, Lugano R, Garc´ıa-Arguinzonis M, Badimon L (2012) LDL-Induced Impairment of Human Vascular Smooth Muscle Cells Repair Function Is Reversed by HMG-CoA Reductase Inhibition. PLoS ONE 7(6): e38935. doi:10.1371/journal.pone.0038935 Editor: Elena Aikawa, Brigham and Women’s Hospital, Harvard Medical School, United States of America Received February 23, 2012; Accepted May 14, 2012; Published June 12, 2012 Copyright: 2012 Padro´ et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by grants from the Spanish Ministery of Science (SAF SAF2010-16549 to LB); from the Instituto Carlos III (Spanish Ministry of Health), FIS-PI071070 and FISPI10-01115 (to TP), CIBEROBN CB06/03 (to LB), REDINSCOR RD06/0003/0015 (to TP), TERCEL RD06/0010/0017 (to LB); Spanish Society of Atherosclerosis (SEA) and ‘‘Fundaci o´n Jesus Serra’’. This project is part of the PROMISE European Training Program (Germany and Spain). RL is recipient of a predoctoral grant from the CIBEROBN (2008-2009) and ICCC (2010-2011). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: lbadimon@csic-iccc.org Introduction Atherosclerotic lesions with a large lipid-necrotic core and a thin fibrous cap are the most prone to rupture [1] triggering the acute ischemic syndromes. Compared with intact caps, those ruptured are usually thinner, and contain higher amount of infiltrated lipids and a paucity of smooth muscle cells (VSMC) [2], the only vascular resident cells that synthesize extracellular matrix compo- nents required for the tensile strength of the fibrous cap of the plaques. In asymptomatic silent disease, plaques are healed by VSMC that accumulate at the sites of rupture, where they secrete an extracellular matrix rich in glycosaminoglycans and type III collagen [3–5]. VSMC number is determined by the net effect of VSMC proliferation, migration, and death or apoptosis. Cell migration is associated with dynamic remodeling of the actin- myosin cytoskeleton [6], which is dependent on the phosphory- lation/dephosphorylation balance of the myosin regulatory light chain (MRLC) [7–8]. A key pathogenic event in the development of atherosclerosis is the retention of colloidal atherogenic lipoproteins, primarily low density lipoprotein (LDL), in the arterial intima. This retention occurs when LDL bind to the extracellular matrix proteoglycans, as versican [9–11] that induces LDL aggregation (agLDL) and leads to dysfunction of the vascular resident cells [12–13]. agLDL upregulate the expression of low-density lipoprotein receptor- related protein 1 (LRP1) [14–15], which in turn internalizes significant amounts of cholesteryl esters from agLDL contributing to the transformation of VSMC into lipid loaded cells [15–17]. In previous studies we have demonstrated that agLDL decrease phosphorylated-MRLC (P-MRLC) levels and impairs migration and wound repair in VSMC [18–19]. These effects could contribute to the development of soft-high risk plaques with decreased VSMC accumulation. Statins, inhibitors of 3-hydroxy-methylglutaryl coenzyme A (HMG-CoA) reductase, are widely used cholesterol-lowering drugs [20–21] that significantly reduce the presentation of cardiovascu- lar events in patients either with or without previous coronary heart disease [22–26]. Vascular remodelling and stabilization of vulnerable plaques are presumed to be major contributors in these beneficial effects. To this respect, intravascular ultrasound imaging (IVUS)-end point studies with statins have shown that they reduce atherosclerotic plaque burden in treated patients [27] and the PLoS ONE | www.plosone.org 1 June 2012 | Volume 7 | Issue 6 | e38935