Endothelins: Effect on Matrix Biosynthesis and Proliferation in Normal and Scleroderma Fibroblasts

Abstract

We investigated the effect of endothelin-1 (ET-1) in normal and systemic sclerosis (SSc) dermal fibroblasts. Collagen type I, collagen type III, and MMP-1 levels in culture supernatants were measured by competition ELISA and cellular mRNA expression was examined by Northern blotting. Mitogenic responses to ET-1 were assessed by [3H]TdR incorporation. ET receptor mRNA expression was examined by RT-PCR analysis of fibroblast RNA and with surface binding studies using radiolabeled ET receptor ligands and specific receptor antagonists. ET-1 enhanced release of collagen types I and III by control and SSc fibroblast strains, but the effects were significantly greater for control cells (p < 0.05). This effect appeared to involve both ETA and ETB receptor subtypes. SSc fibroblasts demonstrated lower constitutive MMP-1 production than control fibroblasts (p < 0.01), but ET-1 treatment decreased MMP-1 in normal fibroblasts to levels observed in SSc. Mitogenic response (percent control [3H]TdR incorporation) to ET-1 for SSc fibroblasts was 130 +/- 34, significantly less (p < 0.01) than that for normal fibroblasts strains (290 +/- 25). This response appeared to be predominantly mediated via the ETA receptor subtype. Surface binding studies suggested a significantly lower level of ETA binding sites in SSc compared with normal fibroblasts (p < 0.05). These data suggest that ET-1 induces a fibrogenic phenotype in normal dermal fibroblasts that resembles that seen in fibroblasts grown from lesional SSc skin. Moreover, SSc cells appear to be refractory to these effects, and this reduced responsiveness is associated with an altered ratio of ETA:ETB receptor expression, supporting a role for ET-1 in the fibrotic pathology of SSc.

Endothelin-1 Induces Expression of Matrix-associated Genes in Lung Fibroblasts through MEK/ERK

“…Previously, we have shown that ET-1 enhances collagen types I and III and decreases MMP-1 mRNA and protein expression in dermal fibroblasts (18,20). In this report, we extend these results by showing that ET-1 in itself is capable of inducing the expression of ECM or ECM-associated genes.…”

“…Total RNA (10 g) was reverse transcribed in a 20-l reaction volume containing an oligonucleotide (dT 18 ) and random decamers (dN 10 ) using M-MLV reverse transcriptase (Promega) for 1 h at 37°C. The cDNA was diluted to 100 l with diethylpyrocarbonate-treated water, and the target was measured by real time PCR FastStart DNA Master SYBR Green (Roche Applied Science) according to the manufacturer's instructions.…”

“…In addition, ET-1 modifies extracellular matrix metabolism (15, 18 -20). For example, ET-1 enhances collagen types I and III and decreases matrix metalloproteinase-1 (MMP-1) mRNA and protein expression in dermal fibroblasts (18,20). However, the signal transduction mechanism and transcription factors through which ET-1 affects gene expression is largely unknown.…”

Estudo de associação entre anticorpos anticardiolipinas e fenômenos vasculares periféricos em pacientes com esclerodermia sistêmica

“…The ET-1, a potent endogenous vasoconstrictor, is mitogen for fibroblasts, smooth muscle cells and endothelial cells. 3 Various auto-antibodies have been found in ES, among them, the antiphospholipids (AAF). Marie and cols 2 , studying 69 patients suffering from ES, found positiviness for these auto-antibodies in 19% of them.…”

“…6 In some studies the presence of aCLs was associated with the appearing of digital micro scars. 2,3 The present analysis was carried out to verify the prevailance of aCLs in the local population with ES and such auto-antibodies are associated with peripheral vascular disorders such as ulcers and digital necrosis, digital micro scars, teleangiectasies and peripheral thrombosis.…”