title: [Change of mitogen-activated protein kinase phosphatase-1 in heart and aorta of SHR and its effect on proliferation of vascular smooth muscle cells stimulated by angiotensin II].
abstract: OBJECTIVE
  To investigate the role of mitogen-activated protein kinase phosphatase-1 (MKP-1) in the regulation of cells proliferation, the expression of MKP-1 and extracellular signal-regulated kinase-1 (ERK-1) in heart and aorta of spontaneous hypertensive rat (SHR) and WKY were studied. We also investigated the effect of MKP-1 genes,which were transfected into vascular smooth muscle cells (VSMC) using the classical calcium phosphate coprecipitation technique, on the incorporation of 3H-TdR in VSMC stimulated by angiotensin II (Ang II).
  
  
  RESULTS
  (1) Compared with that of WKY, MKP-1 expression in heart and aorta were significantly decreased by 53% (P < 0.01) and 45% (P < 0.01) in SHR, respectively. While the expression of ERK-1 in heart and aorta of SHR were higher than that of WKY (P < 0.01). The ratio of ERK-1/MKP-1 in heart and aorta of SHR were significantly higher than that of WKY. (2) 3H-TdR incorporation in VSMC stimulated by Ang II (10(-7) mol/L) was increased by 207% (P < 0.01), compared with control group. In the transfected cells with wild MKP-1 gene, Ang II-induced incorporation of 3H-TdR lowered 63%, compared with untransfected cells (P < 0.05). There were no marked inhibitive role between mutant MKP-1-transfected cells and blank vector-transfected cells in response to Ang II, compared with Ang II group (P > 0.05).
  
  
  CONCLUSIONS
  These results showed that the expression of ERK-1 in heart and aorta isolated from SHR, which stimulated proliferation and hypertrophy of cells, is higher than that of MKP-1 which dephosphorylates and inactivated ERK-1. In addition, MKP-1 significantly inhibits Ang II-stimulated proliferation of VSMC.
authors.affiliation: Institute of Cardiovascular Disease, The First Hospital, Beijing University, Beijing 100034, China.
authors.forename: San-Bao
authors.initials: SB
authors.lastname: Chai
authors.forename: Ding-Fang
authors.initials: DF
authors.lastname: Bu
authors.forename: Li-Jia
authors.initials: LJ
authors.lastname: Tong
authors.forename: Chao-Shu
authors.initials: CS
authors.lastname: Tang
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001011:Aorta / Q000166:cytology / Q000201:enzymology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D054638:Dual Specificity Phosphatase 1 / Q000378:metabolism*; D006321:Heart; D006973:Hypertension / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D009206:Myocardium / Q000166:cytology / Q000201:enzymology*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY
chemical_list: D000804:Angiotensin II; D048052:Mitogen-Activated Protein Kinase 3; D054638:Dual Specificity Phosphatase 1