TGF-beta(1) and prepro-ANP mRNAs are differentially regulated in exercise-induced cardiac hypertrophy.
The induction of transforming growth factor (TGF)-beta and prepro-atrial natriuretic peptide (ANP) mRNAs represent hallmark features of pathological cardiac hypertrophy. The present study examined whether this pattern of mRNA expression was conserved in a physiological model of cardiac hypertrophy. To address this thesis, female Sprague-Dawley rats were individually housed and permitted to run freely. Voluntary exercise for 3 and 6 wk resulted in biventricular hypertrophy and increased cytochrome c oxidase activity in the triceps muscle. In the hypertrophied left ventricle, the steady-state mRNA level of the cardiac fetal gene prepro-ANP and the extracellular matrix proteins preprocollagen-alpha(1) and fibronectin were similar in exercise-trained and sedentary rats. By contrast, an increased expression of TGF-beta(1) mRNA was observed, whereas TGF-beta(3) mRNA level was unchanged in the hypertrophied left ventricle of exercise-trained compared with sedentary rats. These data highlight a heterogeneity in the regulation of TGF-beta isoforms, and the increased expression of ventricular TGF-beta(1) mRNA in physiological cardiac hypertrophy may contribute to myocardial remodeling.
Calderone
A
A
Centre de Recherche de l'Institut de Cardiologie de Montréal, Université de Montréal, Montreal, Quebec, Canada H1T 1C8. calderon@icm.umontreal.ca
Murphy
R J
RJ
Lavoie
J
J
Colombo
F
F
Béliveau
L
L
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000235:genetics*; D003094:Collagen; D005260:Female; D005333:Fetus; D005353:Fibronectins / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D006321:Heart / Q000187:drug effects / Q000502:physiology*; D006352:Heart Ventricles; D023421:Models, Animal; D009206:Myocardium / Q000378:metabolism*; D009638:Norepinephrine / Q000494:pharmacology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D011347:Procollagen / Q000235:genetics; D011498:Protein Precursors / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D014158:Transcription, Genetic; D016212:Transforming Growth Factor beta / Q000235:genetics*
D005353:Fibronectins; D011347:Procollagen; D011498:Protein Precursors; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta; C032431:preprocollagen; D009320:Atrial Natriuretic Factor; D003094:Collagen; D009638:Norepinephrine