Role of transforming growth factor-beta in maintenance of function of cultured neonatal cardiac myocytes. Autocrine action and reversal of damaging effects of interleukin-1.
The three isoforms of transforming growth factor-beta (TGF-beta) have previously been implicated in embryonic development of the heart as well as in repair of myocardial damage after ischemia/reperfusion injury. TGF-beta 1 has also been localized intracellularly to both mitochondria and contractile filaments of cardiac myocytes, although its role in these structures has not been defined. We now report that exogenous TGF-beta stabilizes the beating rate of neonatal rat cardiac myocytes cultured on fibroblast matrix, and sustains their spontaneous rhythmic beating in serum-free medium. Moreover, using blocking antibodies to TGF-beta, we show that endogenous TGF-beta secreted by these myocytes acts in an autocrine fashion to maintain their beating rate. In contrast, IL-1 beta, an inflammatory mediator secreted by immune cells during myocardial injury, inhibits the beating of cardiac myocytes, and TGF-beta can overcome this inhibition. The antagonistic effects of TGF-beta and IL-1 were not observed when the myocytes were cultured on gelatin, as compared to native fibroblast matrix. The data indicate that TGF-beta is an important regulator of contractile function of the heart and have significant implications for understanding cardiac physiology in health and disease.
Roberts
A B
AB
Laboratory of Chemoprevention, National Cancer Institute, Bethesda, Maryland 20892.
Roche
N S
NS
Winokur
T S
TS
Burmester
J K
JK
Sporn
M B
MB
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D002478:Cells, Cultured; D006321:Heart / Q000187:drug effects*; D006339:Heart Rate / Q000187:drug effects; D007375:Interleukin-1 / Q000633:toxicity*; D009200:Myocardial Contraction / Q000187:drug effects; D051381:Rats; D016212:Transforming Growth Factor beta / Q000494:pharmacology*
D007375:Interleukin-1; D016212:Transforming Growth Factor beta