Kc. Flanders et al., AUTOINDUCTION OF MESSENGER-RNA AND PROTEIN EXPRESSION FOR TRANSFORMING GROWTH FACTOR-BETA-S IN CULTURED CARDIAC-CELLS, Journal of Molecular and Cellular Cardiology, 27(2), 1995, pp. 805-812
Although transforming growth factor-beta s (TGF-beta s) are expressed
widely in both adult and embryonic rat heart, both mRNA and protein ex
pression increase following ischemic injury, Furthermore, exogenous ad
ministration of TGF-beta decreases cardiac damage following ischemia-r
eperfusion in rats, We have found that treatment of primary cultures o
f neonatal rat cardiomyocytes or cardiac fibroblasts with TGF-beta 1,
2, or 3 results in increased expression of TGF-beta 1, 2, and 3 mRNA,
TGF-beta 2 was generally the least effective isoform in inducing TGF-b
eta expression. In cardiac fibroblasts mRNA expression of all TGF-beta
s increased 2-3-fold following 1 h of treatment and decreased to cont
rol levels by 8 h which was accompanied by a 2.5- and 2.3-fold increas
e in TGF-beta 1 and 2 protein secretion, respectively By 48 h of treat
ment mRNA levels for TGF-beta s 2 and 3 were less than 10% of control
levels, In cardiomyocytes two-five-fold increases in mRNA levels were
observed following 1-24 h of TGF-beta 1 treatment, but TGF-beta 1 and
3 mRNA levels returned to control values by 48 h while TGF-beta 2 mRNA
expression remained elevated, TGF-beta 1 and 2 protein secreted by th
e cardiac myocytes was increased 2.9- and 1.7-fold, respectively. Auto
induction of TGF-beta s may play a beneficial role in cardiac wound he
aling by sustaining transient increases in TGF-beta levels from either
endogenous synthesis or exogenous application.