Platelet CD36 promotes thrombosis by activating redox sensor ERK5 in hyperlipidemic conditions.
Atherothrombosis is a process mediated by dysregulated platelet activation that can cause life-threatening complications and is the leading cause of death by cardiovascular disease. Platelet reactivity in hyperlipidemic conditions is enhanced when platelet scavenger receptor CD36 recognizes oxidized lipids in oxidized low-density lipoprotein (oxLDL) particles, a process that induces an overt prothrombotic phenotype. The mechanisms by which CD36 promotes platelet activation and thrombosis remain incompletely defined. In this study, we identify a mechanism for CD36 to promote thrombosis by increasing activation of MAPK extracellular signal-regulated kinase 5 (ERK5), a protein kinase known to be exquisitely sensitive to redox stress, through a signaling pathway requiring Src kinases, NADPH oxidase, superoxide radical anion, and hydrogen peroxide. Pharmacologic inhibitors of ERK5 blunted platelet activation and aggregation in response to oxLDL and targeted genetic deletion of ERK5 in murine platelets prevented oxLDL-induced platelet deposition on immobilized collagen in response to arterial shear. Importantly, in vivo thrombosis experiments after bone marrow transplantation from platelet-specific ERK5 null mice into hyperlipidemic apolipoprotein E null mice showed decreased platelet accumulation and increased thrombosis times compared with mice transplanted with ERK5 expressing control bone marrows. These findings suggest that atherogenic conditions critically regulate platelet CD36 signaling by increasing superoxide radical anion and hydrogen peroxide through a mechanism that promotes activation of MAPK ERK5.
Department of Cell Biology, Neurobiology, and Anatomy, Medical College of Wisconsin, Milwaukee, WI.|Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI.
Moua
M
Yang
Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC.
Brian C
BC
Cooley
Department of Cellular and Molecular Medicine, Cleveland Clinic Lerner Research Institute, Cleveland, OH.
Wei
W
Li
Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI.
Yiliang
Y
Chen
Department of Biophysics, Medical College of Wisconsin, Milwaukee, WI.
Jeannette
J
Vasquez-Vivar
Department of Biology, Denison University, Granville, OH.
Na'il O
NO
Scoggins
Aab Cardiovascular Research Institute, University of Rochester, Rochester, NY; and.
Scott J
SJ
Cameron
Aab Cardiovascular Research Institute, University of Rochester, Rochester, NY; and.
Craig N
CN
Morrell
Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI.|Department of Medicine, Medical College of Wisconsin, Milwaukee, WI.
Roy L
RL
Silverstein
D064591:Allografts; D000818:Animals; D001057:Apolipoproteins E / Q000235:genetics / Q000276:immunology; D001792:Blood Platelets / Q000276:immunology* / Q000473:pathology; D016026:Bone Marrow Transplantation; D018955:CD36 Antigens / Q000235:genetics / Q000276:immunology*; D006801:Humans; D006949:Hyperlipidemias / Q000235:genetics / Q000276:immunology* / Q000473:pathology; D008077:Lipoproteins, LDL / Q000235:genetics / Q000276:immunology; D020935:MAP Kinase Signaling System / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008817:Mice, Mutant Strains; D048054:Mitogen-Activated Protein Kinase 7 / Q000235:genetics / Q000276:immunology*; D019255:NADPH Oxidases / Q000235:genetics / Q000276:immunology; D015539:Platelet Activation / Q000235:genetics / Q000276:immunology*; D013927:Thrombosis / Q000235:genetics / Q000276:immunology* / Q000473:pathology
D001057:Apolipoproteins E; D018955:CD36 Antigens; D008077:Lipoproteins, LDL; C099252:oxidized low density lipoprotein; D019255:NADPH Oxidases; D048054:Mitogen-Activated Protein Kinase 7