An Endostatin-derived Peptide Interacts with Integrins and Regulates Actin Cytoskeleton and Migration of Endothelial Cells

Abstract

Endostatin, the C-terminal fragment of collagen XVIII, is a potent inhibitor of angiogenesis and endothelial cell migration. To define its critical cell interaction domains we used endostatin-derived synthetic peptides containing surface-exposed sequences. We observed that, when immobilized, an arginine-rich peptide of 11 amino acids from its N terminus efficiently promoted endothelial cell adhesion through ␤ 1 integrin-and heparin-dependent mechanisms. In addition, the peptide induced the formation of membrane ruffles and focal contacts. In the soluble form, the peptide inhibited basic fibroblast growth factor-induced directional migration and tubular morphogenesis of microvascular endothelial cells. Accordingly, the peptide induced the loss of focal adhesions and actin stress fibers in these cells. Substitution of the arginine residues with alanines resulted in the loss of these properties. In the current study we describe a putative integrin-binding sequence with anti-migratory activity within endostatin.

Peptides Derived from Human Decorin Leucine-rich Repeat 5 Inhibit Angiogenesis

“…The advantage for peptides are their small sizes, simplicity in synthesizing, lack of toxicity, immune reaction to the host system, and viability for chemical modifications (2). Several anti-angiogenic peptides have been obtained from various domains of endogenous proteins, including the Ex domain of MMP-2, Ig domains of VEGFR1, TAR domains of TSP1, as well as endostatin (5,28,38,39). This work represents the first report of anti-angiogenic peptides derived from the LRR domains.…”

“…Cell Migration Assay-Migration assay was performed using Falcon cell culture inserts as described previously with modifications (28). Briefly, HUVECs were starved overnight, trypsinized, and suspended at a final concentration of 3 ϫ 10 5 cells/ml.…”

Endogenous Inhibitors of Angiogenesis

“…Recent work has shown the identity of a specific arginine-rich sequence motif of human endostatin that interacts with endothelial cell surface h 1 integrin and heparin and inhibits endothelial cell migration and tube formation. This Arg-Gly-Asp (RGD)-independent sequence is likely to be the motif responsible for the antiangiogenic activity of endostatin (50).…”

Angiogenic factors are elevated in overweight and obese individuals

“…Endostatin, a C-terminal fragment of collagen XVIII, functions as a potent inhibitor of angiogenesis and endothelial cell migration. It interacts with receptors, possibly integrins on the endothelial cells 47 and downregulates many signaling pathways in human microvascular endothelium associated with proangiogenic activity. 48 Here we report that endostatin levels are higher in overweight and obese males compared to lean subjects.…”