Alternagin-C, a disintegrin-like protein, induces vascular endothelial cell growth factor (VEGF) expression and endothelial cell proliferation in vitro.
Alternagin-C (ALT-C), a disintegrin-like protein purified from the venom of the Brazilian snake Bothrops alternatus, interacts with the major collagen I receptor, the alpha(2)beta(1) integrin, inhibiting collagen binding. Here we show that ALT-C also inhibits the adhesion of a mouse fibroblast cell line (NIH-3T3) to collagen I (IC(50) 2.2 microm). In addition, when immobilized on plate wells, ALT-C supports the adhesion of this cell line as well as of human vein endothelial cell (HUVEC). ALT-C (3 microm) does not detach cells that were previously bound to collagen I. ALT-C (5 nm) induces HUVEC proliferation in vitro, and it inhibits the positive effect of vascular endothelial growth factor (VEGF) or FGF-2 on the proliferation of these cells, thus suggesting a common mechanism for these proteins. Gene expression analysis of human fibroblasts growing on ALT-C- or collagen-coated plates showed that ALT-C and collagen I induce a very similar pattern of gene expression. When compared with cells growing on plastic only, ALT-C up-regulates the expression of 45 genes including the VEGF gene and down-regulates the expression of 30 genes. Fibroblast VEGF expression was confirmed by RT-PCR and ELISA assay. Up-regulation of the VEGF gene and other growth factors could explain the positive effect on HUVEC proliferation. ALT-C also strongly activates Akt/PKB phosphorylation, a signaling event involved in endothelial survival and angiogenesis. In conclusion, ALT-C acts as a survival factor, promoting adhesion and endothelial cell proliferation.
Cominetti
Márcia R
MR
Department of Ciências Fisiológicas, Universidade Federal de São Carlos, SP, 13565-905, Brazil.
Terruggi
Cristina H B
CH
Ramos
Oscar H P
OH
Fox
Jay W
JW
Mariano-Oliveira
Andrea
A
De Freitas
Marta S
MS
Figueiredo
Camila C
CC
Morandi
Veronica
V
Selistre-de-Araujo
Heloisa S
HS
D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002455:Cell Division / Q000187:drug effects; D024042:Collagen Type I / Q000378:metabolism; D019483:Disintegrins / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects*; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D014471:Umbilical Veins; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*
D024042:Collagen Type I; D019483:Disintegrins; D011518:Proto-Oncogene Proteins; D042461:Vascular Endothelial Growth Factor A; C481346:alternagin-C; C494918:AKT1 protein, human; D017346:Protein Serine-Threonine Kinases; D051057:Proto-Oncogene Proteins c-akt