%0 Journal Article
%T Connective tissue growth factor expression after angiotensin II exposure is dependent on transforming growth factor
%A Alec Falkenham
%A Chloe Kok Sum Wong
%A Jean-Francois L¨¦gar¨¦
%A Tanya Myers
%J Journal of the Renin
%@ 1752-8976
%D 2018
%R 10.1177/1470320318759358
%X Transforming growth factor-¦Â (TGF-¦Â) and connective tissue growth factor (CTGF) are often described as the initial pro-fibrotic mediators upregulated early in fibrosis models dependent on angiotensin II (Ang-II). In the present study, we explore the mechanistic link between TGF-¦Â and CTGF expression by using a novel TGF-¦Â trap. NIH/3T3 fibroblasts were subjected to TGF-¦Â with or without TGF-¦Â trap or 1D11 antibody, CTGF or CTGF plus TGF-¦Â for six or 24 hours, and then used for quantitative real-time polymerase chain reaction (qRT-PCR) or immunocytochemistry. Male C57BL/6 mice were infused with Ang-II and randomly assigned TGF-¦Â trap for six or 24 hours. Hearts were harvested for histological analyses, qRT-PCR and western blotting. Exogenous TGF-¦Â-induced fibroblasts resulted in significant upregulation of CTGF, TGF-¦Â and type I collagen transcript levels in vitro. Additionally, TGF-¦Â promoted the differentiation of fibroblasts into ¦Á-SMA+ myofibroblasts. CTGF expression was reduced by the addition of TGF-¦Â trap or neutralizing antibody, confirming that its expression is dependent on TGF-¦Â signaling. In contrast, exogenous CTGF did not appear to have an effect on fibroblast production of pro-fibrotic transcripts or fibroblast differentiation. Ang-II infusion in vivo led to a significant increase in TGF-¦Â and CTGF mRNA expression at six and 24 hours with corresponding changes in Smad2 phosphorylation (pSmad2), indicative of increased TGF-¦Â signaling. Ang-II animals that received the TGF-¦Â trap demonstrated reduced CTGF mRNA levels and pSmad2 at six hours, suggesting that early CTGF expression is dependent on TGF-¦Â signaling. We demonstrated that CTGF expression is dependent on TGF-¦Â signaling both in vitro and in vivo in a model of myocardial fibrosis. This also suggests that early myocardial CTGF mRNA expression (six hours) after Ang-II exposure is likely dependent on latent TGF-¦Â activation via the canonical Smad-dependent pathway in resident cardiac cells
%K Cardiac
%K TGF-¦Â
%K CTGF
%K inflammation
%K myocardial fibrosis
%K fibroblasts
%K angiotensin-II
%K TGF-¦Â trap
%U https://journals.sagepub.com/doi/full/10.1177/1470320318759358