title: Inhibitory effect of antisense oligodeoxynucleotide to p44/p42 MAPK on angiotensin II-induced hypertrophic response in cultured neonatal rat cardiac myocyte.
abstract: OBJECTIVE
  To explore the inhibitory effect of antisense oligonucleotide (ODN) to mitogen activated protein kinase(MAPK) on cardiomyocyte hypertrophy induced by angiotensin II (Ang II).
  
  
  METHODS
  A 17-mer phosphorothioate-protected antisense ODN directed against the initiation of translation sites of the p42 and p44 MAPK isoforms by liposomal transfection was applied to inhibit the translation of p44/p42 MAPK mRNA. The sense and random ODNs to p44/p42MAPK were used as sequence controls. Neonatal cardiac myocytes were exposed to Ang II (10 nmol/L) for 5 min and then harvested in lysis buffer for the measurement of the activity and the phosphorylated protein content of p44/p42MAPK that were tested by P-81 phosphocellulose filter paper method and Western blotting, respectively. The rate of protein synthesis by [3H]leucine incorporation and the diameter of cell were measured after exposure to Ang II for 24 h and 72 h, respectively.
  
  
  RESULTS
  In cardiac myocyte Ang II increased p44/p42 MAPK activity and phosphorylated protein content by 140 % and 699 %, and also increased [3H]leucine incorporation and cell diameter by 40 % and 27 %. c-fos and c-myc mRNAs were induced significantly after exposure to Ang II. Antisense ODN to p44/p42MAPK (0.2 micromol/L) reduced Ang II-induced MAPK activity by 30 %, and phophorylated MAPK protein expression by 59 % in cardiac myocyte, and inhibited c-fos and c-myc mRNA expression induced by Ang II by 44 % and 43 %, respectively. The diameter and the rate of protein synthesis of cardiac myocyte induced by Ang II were decreased by 16 % and 22 % after pretreatment with antisense ODN to p44/p42MAPK.
  
  
  CONCLUSIONS
  Antisense ODN to p44/p42 MAPK inhibited the increase of rate of protein synthesis, and the augmentation of cell diameter and expression of c-fos and c-myc mRNA induced by Ang II in cultured cardiac myocytes. p44/p42 MAPK played a critical role in the hypertrophic response induced by Ang II in cultured neonatal rat cardiac myocytes.
authors.affiliation: Laboratory of Molecular Pharmacology, Xiang Ya School of Medicine, Central South University, Changsha 410078, China. zhangshiqintj@hotmail.com
authors.forename: Shi-Qin
authors.initials: SQ
authors.lastname: Zhang
authors.forename: Bo
authors.initials: B
authors.lastname: Ding
authors.forename: Zhao-Gui
authors.initials: ZG
authors.lastname: Guo
authors.forename: Yun-Xia
authors.initials: YX
authors.lastname: Li
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D006332:Cardiomegaly / Q000473:pathology; D002478:Cells, Cultured; D015870:Gene Expression / Q000187:drug effects; D016762:Genes, fos; D016259:Genes, myc; D019950:Mitogen-Activated Protein Kinase 1 / Q000235:genetics / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism*; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017208:Rats, Wistar
chemical_list: D020319:Oligodeoxyribonucleotides, Antisense; D012333:RNA, Messenger; D000804:Angiotensin II; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases