title: A novel p38 MAPK target dyxin is rapidly induced by mechanical load in the heart.
abstract: Dyxin is a novel LIM domain protein acting as a transcriptional cofactor with GATA transcription factors. Here, we characterized dyxin as a p38 mitogen-activated protein kinase (MAPK) regulated gene, since combined upstream MAPK kinase 3b and wild-type p38 alpha MAPK gene transfer increased left ventricular dyxin mRNA and protein levels in vivo. We also studied cardiac dyxin expression in experimental models of pressure overload and myocardial infarction (MI) in vivo. Angiotensin II infusion increased left ventricular dyxin mRNA levels (9.4-fold, p<0.001) rapidly at 6 h followed by induction of protein levels. Furthermore, simultaneous administration of p38 MAPK inhibitor SB203580 abolished angiotensin II-induced activation of dyxin gene expression. During the post-infarction remodeling process, increased dyxin mRNA levels (7.7-fold, p<0.01) were noted at day 1 followed by the increase in proteins levels at 2 weeks after MI (1.5-fold, p<0.05). Moreover, direct wall stretch by using isolated rat heart preparation as well as direct mechanical stretch of cardiomyocytes in vitro activated dyxin gene expression within 1 h. Our results indicate that dyxin expression is rapidly upregulated in response to mechanical load, this increase being at least partly mediated by p38 MAPK. These results suggest that dyxin may play an important role in regulating hypertrophic process.
authors.affiliation: Department of Pharmacology and Toxicology, Biocenter Oulu, University of Oulu, Oulu, Finland.
authors.forename: Hanne
authors.initials: H
authors.lastname: Luosujärvi
authors.forename: Jani
authors.initials: J
authors.lastname: Aro
authors.forename: Heikki
authors.initials: H
authors.lastname: Tokola
authors.forename: Hanna
authors.initials: H
authors.lastname: Leskinen
authors.forename: Olli
authors.initials: O
authors.lastname: Tenhunen
authors.forename: Réka
authors.initials: R
authors.lastname: Skoumal
authors.forename: István
authors.initials: I
authors.lastname: Szokodi
authors.forename: Heikki
authors.initials: H
authors.lastname: Ruskoaho
authors.forename: Jaana
authors.initials: J
authors.lastname: Rysä
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000804:Angiotensin II; D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D056970:Co-Repressor Proteins; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D006321:Heart / Q000503:physiopathology*; D006352:Heart Ventricles / Q000378:metabolism; D006973:Hypertension / Q000139:chemically induced / Q000503:physiopathology; D066298:In Vitro Techniques; D060588:LIM Domain Proteins; D008297:Male; D009203:Myocardial Infarction / Q000503:physiopathology; D009206:Myocardium / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013314:Stress, Mechanical; D014662:Vasoconstrictor Agents; D020257:Ventricular Remodeling; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D002352:Carrier Proteins; D056970:Co-Repressor Proteins; D060588:LIM Domain Proteins; C549459:Lmcd1 protein, rat; D012333:RNA, Messenger; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D048051:p38 Mitogen-Activated Protein Kinases