CD36 Mediates the In Vitro Inhibitory Effects of Thrombospondin-1 on Endothelial Cells

Abstract

Thrombospondin-1 (TSP-1) is a naturally occurring inhibitor of angiogenesis that is able to make normal endothelial cells unresponsive to a wide variety of inducers. Here we use both native TSP-1 and small antiangiogenic peptides derived from it to show that this inhibition is mediated by CD36, a transmembrane glycoprotein found on microvascular endothelial cells. Both IgG antibodies against CD36 and glutathione-S-transferase–CD36 fusion proteins that contain the TSP-1 binding site blocked the ability of intact TSP-1 and its active peptides to inhibit the migration of cultured microvascular endothelial cells. In addition, antiangiogenic TSP-1 peptides inhibited the binding of native TSP-1 to solid phase CD36 and its fusion proteins, as well as to CD36-expressing cells. Additional molecules known to bind CD36, including the IgM anti-CD36 antibody SM∅, oxidized (but not unoxidized) low density lipoprotein, and human collagen 1, mimicked TSP-1 by inhibiting the migration of human microvascular endothelial cells. Transfection of CD36-deficient human umbilical vein endothelial cells with a CD36 expression plasmid caused them to become sensitive to TSP-1 inhibition of their migration and tube formation. This work demonstrates that endothelial CD36, previously thought to be involved only in adhesion and scavenging activities, may be essential for the inhibition of angiogenesis by thrombospondin-1.

CD36: Implications in cardiovascular disease

“…In addition to facilitating fatty acid transport into adipocytes and cardiac and skeletal muscle (and perhaps other cells), CD36 was recently shown to be a sensor for fatty acids in taste buds, eliciting a secretory response in the gut (Laugerette, et al, 2005). CD36 interacts with ligands which contain a thrombospondin 1 (TSP-1) type 1 repeat element (TSR) to inhibit a pro-angiogenic signal, resulting in endothelial cell apoptosis (Dawson, Pearce, Zhong, Silverstein, Frazier, & Bouck, 1997,Dawson, et al, 1999,Jimenez, Volpert, Crawford, Febbraio, Silverstein, & Bouck, 2000,Miao, Seng, Duquette, Lawler, Laus, & Lawler, 2001,Simantov, Febbraio & Silverstein, 2005.…”

“…One function of this receptor-ligand pair with relevance to cardiovascular biology and pathology is inhibition of angiogenesis (Dawson, Pearce, Zhong, Silverstein, Frazier, & Bouck, 1997). Angiogenesis is the body's response to ischemia and vascular injury, and work has demonstrated that oxidatively modified LDL (oxLDL) which may be found in hyperlipidemic states, including atherosclerosis, diabetes and the metabolic syndrome, can inhibit endothelial cell proliferation and angiogenesis (Chen, et al, 1997,Imanishi, Hano, Matsuo, & Nishio, 2003,Mwaikambo, Sennlaub, Ong, Chemtob, & Hardy, 2006.…”

HER2 signaling modulates the equilibrium between pro- and antiangiogenic factors via distinct pathways: implications for HER2-targeted antibody therapy

“…TSP-1 also inhibits the activity of matrix metalloproteinase-9 (MMP-9) (Ribatti et al, 1998;Rodriguez-Manzaneque et al, 2001). TSP-1 inhibits angiogenesis by binding to the CD36 receptor protein, which is present on the endothelial cell surface (Dawson et al, 1997). Low expression of TSP-1 expression has been associated with increased recurrence rates and decreased overall survival in human cancers (Sargiannidou et al, 2001).…”

Peptides derived from type I thrombospondin repeat-containing proteins of the CCN family inhibit proliferation and migration of endothelial cells

“…Extensive studies on the mechanistic details of the anti-angiogenic activity of thrombospondin 1, the prototype type I thrombospondin repeat containing protein, have implicated CD36 as the cell surface receptor that mediates its effects on endothelial cells (Dawson et al, 1997). CD36 is an 88 kDa transmembrane glycoprotein expressed on endothelial cells and a collagen binding molecule.…”