title: Regulator of G-Protein Signaling 5 Prevents Smooth Muscle Cell Proliferation and Attenuates Neointima Formation.
abstract: OBJECTIVE
  Regulator of G-protein signaling 5 (RGS5) is abundantly expressed in vascular smooth muscle cells (SMCs) and inhibits G-protein signaling by enhancing the guanosine triphosphate-hydrolyzing activity of Gα-subunits. In the present study, we investigated the effects of RGS5 on vascular SMC function in vitro and neointima formation after wire-induced injury in mice and determined the underlying mechanisms.
  
  
  RESULTS
  We found a robust expression of RGS5 in native arteries of C57BL/6 mice and a highly significant downregulation within neointimal lesions 10 and 21 days after vascular injury as assessed by quantitative polymerase chain reaction, immunoblotting, and immunohistochemistry. In vitro, RGS5 was found significantly downregulated after mitogenic stimulation of human coronary artery SMCs. To restore RGS5 levels, SMCs were transduced with adenoviral vectors encoding wild-type RGS5 or a nondegradable mutant. RGS5-WT and, even more prominently, the C2A-RGS5 mutant prevented SMC proliferation and migration. In contrast, the siRNA-mediated knockdown of RGS5 significantly augmented SMC proliferation. Following overexpression of RGS5, fluorescence-activated cell sorting analysis of propidium iodide-stained cells indicated cell cycle arrest in G0/G1 phase. Mechanistically, inhibition of the phosphorylation of the extracellular signal-regulated kinase 1/2 and mitogen-activated protein kinase downstream signaling was shown to be responsible for the anti-proliferative effect of RGS5. Following wire-induced injury of the femoral artery in C57BL/6 mice, adenoviral-mediated overexpression of RGS5-WT or C2A-RGS5 significantly reduced SMC proliferation and neointima formation in vivo.
  
  
  CONCLUSIONS
  Downregulation of RGS5 is an important prerequisite for SMC proliferation in vitro and in vivo. Therefore, reconstitution of RGS5 levels represents a promising therapeutic option to prevent vascular remodeling processes.
authors.affiliation: From the Department of Cardiology and Angiology (J.-M.D., J.D., K.S., J.B., D.G.S.), REBIRTH Excellence Cluster (J.-M.D., T.T., J.B., D.G.S.), and Institute of Molecular and Translational Therapeutic Strategies (IMTTS) (K.S., T.T.), Hannover Medical School, Hannover, Germany; Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany (A.P.); and National Heart and Lung Institute, Imperial College London, London, UK (T.T.).
authors.forename: Jan-Marcus
authors.initials: JM
authors.lastname: Daniel
authors.affiliation: From the Department of Cardiology and Angiology (J.-M.D., J.D., K.S., J.B., D.G.S.), REBIRTH Excellence Cluster (J.-M.D., T.T., J.B., D.G.S.), and Institute of Molecular and Translational Therapeutic Strategies (IMTTS) (K.S., T.T.), Hannover Medical School, Hannover, Germany; Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany (A.P.); and National Heart and Lung Institute, Imperial College London, London, UK (T.T.).
authors.forename: André
authors.initials: A
authors.lastname: Prock
authors.affiliation: From the Department of Cardiology and Angiology (J.-M.D., J.D., K.S., J.B., D.G.S.), REBIRTH Excellence Cluster (J.-M.D., T.T., J.B., D.G.S.), and Institute of Molecular and Translational Therapeutic Strategies (IMTTS) (K.S., T.T.), Hannover Medical School, Hannover, Germany; Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany (A.P.); and National Heart and Lung Institute, Imperial College London, London, UK (T.T.).
authors.forename: Jochen
authors.initials: J
authors.lastname: Dutzmann
authors.affiliation: From the Department of Cardiology and Angiology (J.-M.D., J.D., K.S., J.B., D.G.S.), REBIRTH Excellence Cluster (J.-M.D., T.T., J.B., D.G.S.), and Institute of Molecular and Translational Therapeutic Strategies (IMTTS) (K.S., T.T.), Hannover Medical School, Hannover, Germany; Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany (A.P.); and National Heart and Lung Institute, Imperial College London, London, UK (T.T.).
authors.forename: Kristina
authors.initials: K
authors.lastname: Sonnenschein
authors.affiliation: From the Department of Cardiology and Angiology (J.-M.D., J.D., K.S., J.B., D.G.S.), REBIRTH Excellence Cluster (J.-M.D., T.T., J.B., D.G.S.), and Institute of Molecular and Translational Therapeutic Strategies (IMTTS) (K.S., T.T.), Hannover Medical School, Hannover, Germany; Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany (A.P.); and National Heart and Lung Institute, Imperial College London, London, UK (T.T.).
authors.forename: Thomas
authors.initials: T
authors.lastname: Thum
authors.affiliation: From the Department of Cardiology and Angiology (J.-M.D., J.D., K.S., J.B., D.G.S.), REBIRTH Excellence Cluster (J.-M.D., T.T., J.B., D.G.S.), and Institute of Molecular and Translational Therapeutic Strategies (IMTTS) (K.S., T.T.), Hannover Medical School, Hannover, Germany; Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany (A.P.); and National Heart and Lung Institute, Imperial College London, London, UK (T.T.).
authors.forename: Johann
authors.initials: J
authors.lastname: Bauersachs
authors.affiliation: From the Department of Cardiology and Angiology (J.-M.D., J.D., K.S., J.B., D.G.S.), REBIRTH Excellence Cluster (J.-M.D., T.T., J.B., D.G.S.), and Institute of Molecular and Translational Therapeutic Strategies (IMTTS) (K.S., T.T.), Hannover Medical School, Hannover, Germany; Department of General, Visceral, Vascular and Pediatric Surgery, University Hospital Wuerzburg, Wuerzburg, Germany (A.P.); and National Heart and Lung Institute, Imperial College London, London, UK (T.T.). Sedding.Daniel@mh-hannover.de.
authors.forename: Daniel G
authors.initials: DG
authors.lastname: Sedding
mesh_terms: D000818:Animals; D059447:Cell Cycle Checkpoints; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005263:Femoral Artery / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D005786:Gene Expression Regulation; D008297:Male; D008810:Mice, Inbred C57BL; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000293:injuries / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D058426:Neointima; D010766:Phosphorylation; D020710:RGS Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D062326:Re-Epithelialization; D015398:Signal Transduction; D013997:Time Factors; D014161:Transduction, Genetic; D014162:Transfection; D066253:Vascular Remodeling; D057772:Vascular System Injuries / Q000235:genetics / Q000378:metabolism* / Q000473:pathology
chemical_list: D020710:RGS Proteins; C491349:RGS5 protein, human; D012333:RNA, Messenger; C105346:Rgs5 protein, mouse; C535150:MAPK1 protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020929:Mitogen-Activated Protein Kinase Kinases
keywords: neointima; proliferation; signal transduction; vascular remodeling; vascular smooth muscle