Thrombospondin-1 inhibits nitric oxide signaling via CD36 by inhibiting myristic acid uptake.
Although CD36 is generally recognized to be an inhibitory signaling receptor for thrombospondin-1 (TSP1), the molecular mechanism for transduction of this signal remains unclear. Based on evidence that myristic acid and TSP1 each modulate endothelial cell nitric oxide signaling in a CD36-dependent manner, we examined the ability of TSP1 to modulate the fatty acid translocase activity of CD36. TSP1 and a CD36 antibody that mimics the activity of TSP1 inhibited myristate uptake. Recombinant TSP1 type 1 repeats were weakly inhibitory, but an anti-angiogenic peptide derived from this domain potently inhibited myristate uptake. This peptide also inhibited membrane translocation of the myristoylated CD36 signaling target Fyn and activation of Src family kinases. Myristate uptake stimulated cGMP synthesis via endothelial nitric-oxide synthase and soluble guanylyl cyclase. CD36 ligands blocked myristate-stimulated cGMP accumulation in proportion to their ability to inhibit myristate uptake. TSP1 also inhibited myristate-stimulated cGMP synthesis by engaging its receptor CD47. Myristate stimulated endothelial and vascular smooth muscle cell adhesion on type I collagen via the NO/cGMP pathway, and CD36 ligands that inhibit myristate uptake blocked this response. Therefore, the fatty acid translocase activity of CD36 elicits proangiogenic signaling in vascular cells, and TSP1 inhibits this response by simultaneously inhibiting fatty acid uptake via CD36 and downstream cGMP signaling via CD47.
Isenberg
Jeff S
JS
Laboratory of Pathology and Radiation Biology Branch, Center for Cancer Research, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
Jia
Yifeng
Y
Fukuyama
Julia
J
Switzer
Christopher H
CH
Wink
David A
DA
Roberts
David D
DD
D001693:Biological Transport, Active / Q000187:drug effects / Q000502:physiology; D018955:CD36 Antigens / Q000378:metabolism*; D051928:CD47 Antigen / Q000378:metabolism; D002478:Cells, Cultured; D006152:Cyclic GMP / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D050612:Fatty Acid Transport Proteins / Q000378:metabolism; D006801:Humans; D019814:Myristic Acid / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000187:drug effects* / Q000502:physiology; D009569:Nitric Oxide / Q000378:metabolism*; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D010455:Peptides / Q000378:metabolism / Q000494:pharmacology*; D051076:Proto-Oncogene Proteins c-fyn / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects* / Q000502:physiology; D019700:Thrombospondin 1 / Q000378:metabolism / Q000494:pharmacology*; D019061:src-Family Kinases / Q000378:metabolism
D018955:CD36 Antigens; D051928:CD47 Antigen; C497894:CD47 protein, human; D050612:Fatty Acid Transport Proteins; D010455:Peptides; D019700:Thrombospondin 1; D019814:Myristic Acid; D009569:Nitric Oxide; C496314:NOS3 protein, human; D052250:Nitric Oxide Synthase Type III; C494957:FYN protein, human; D051076:Proto-Oncogene Proteins c-fyn; D019061:src-Family Kinases; D006152:Cyclic GMP