Angiogenesis in collagen I requires alpha(2)beta(1) ligation of a GFP* GER sequence and possibly p38 MAPK activation and focal adhesion disassembly

作者：Sweeney SM; DiLullo G; Slater SJ; Martinez J; Iozzo RV; Lauer Fields JL; Fields GB; Antonio JDS^*

来源：Journal of Biological Chemistry, 2003, 278(33): 30516-30524.

DOI：10.1074/jbc.M304237200

Angiogenesis depends on proper collagen biosynthesis and cross-linking, and type I collagen is an ideal angiogenic scaffold, although its mechanism is unknown. We examined angiogenesis using an assay wherein confluent monolayers of human umbilical vein endothelial cells were overlain with collagen in a serum-free defined medium. Small spaces formed in the cell layer by 2 h, and cells formed net-like arrays by 6-8 h and capillary-like lumens by 24 h. Blocking of alpha(2)beta(1), but not alpha(1) or alpha(v)beta(3) integrin function halted morphogenesis. We found that a triple-helical, homotrimeric peptide mimetic of a putative alpha(2)beta(1) binding site: alpha(1) (I) 496-507 GARGERGFP*GER (where single-letter amino acid nomenclature is used, P*=hydroxyproline) inhibited tube formation, whereas a peptide carrying another putative site: alpha(1) (I) 127-138 GLP*GERGRP*GAP* or control peptides did not. A chemical inhibitor of p38 mitogen-activated protein kinase (p38 MAPK), SB202190, blocked tube formation, and p38 MAPK activity was increased in collagen-treated cultures, whereas targeting MAPK kinase (MEK), focal adhesion kinase (FAK), or phosphatidylinositol 3-kinase (PI3K) had little effect. Collagen-treated cells had fewer focal adhesions and 3- to 5-fold less activated FAK. Thus capillary morphogenesis requires endothelial alpha(2)beta(1) integrin engagement of a single type I collagen integrin-binding site, possibly signaling via p38 MAPK and focal adhesion disassembly/FAK inactivation.

• 出版日期2003-8-15