Yang Moua, Li Wei, Harberg Calvin, Chen Wenjing, Yue Hong, Ferreira Renan B, Wynia-Smith Sarah L, Carroll Kate S, Zielonka Jacek, Flaumenhaft Robert, Silverstein Roy L, Smith Brian C
Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI.
Blood Research Institute, Versiti Blood Center of Wisconsin, Milwaukee, WI.
Blood Adv. 2020 Sep 22;4(18):4494-4507. doi: 10.1182/bloodadvances.2020001609.
Arterial thrombosis in the setting of dyslipidemia promotes clinically significant events, including myocardial infarction and stroke. Oxidized lipids in low-density lipoproteins (oxLDL) are a risk factor for athero-thrombosis and are recognized by platelet scavenger receptor CD36. oxLDL binding to CD36 promotes platelet activation and thrombosis by promoting generation of reactive oxygen species. The downstream signaling events initiated by reactive oxygen species in this setting are poorly understood. In this study, we report that CD36 signaling promotes hydrogen peroxide flux in platelets. Using carbon nucleophiles that selectively and covalently modify cysteine sulfenic acids, we found that hydrogen peroxide generated through CD36 signaling promotes cysteine sulfenylation of platelet proteins. Specifically, cysteines were sulfenylated on Src family kinases, which are signaling transducers that are recruited to CD36 upon recognition of its ligands. Cysteine sulfenylation promoted activation of Src family kinases and was prevented by using a blocking antibody to CD36 or by enzymatic degradation of hydrogen peroxide. CD36-mediated platelet aggregation and procoagulant phosphatidylserine externalization were inhibited in a concentration-dependent manner by a panel of sulfenic acid-selective carbon nucleophiles. At the same concentrations, these probes did not inhibit platelet aggregation induced by the purinergic receptor agonist adenosine diphosphate or the collagen receptor glycoprotein VI agonist collagen-related peptide. Selective modification of cysteine sulfenylation in vivo with a benzothiazine-based nucleophile rescued the enhanced arterial thrombosis seen in dyslipidemic mice back to control levels. These findings suggest that CD36 signaling generates hydrogen peroxide to oxidize cysteines within platelet proteins, including Src family kinases, and lowers the threshold for platelet activation in dyslipidemia.
血脂异常情况下的动脉血栓形成会引发包括心肌梗死和中风在内的具有临床意义的事件。低密度脂蛋白中的氧化脂质(oxLDL)是动脉粥样硬化血栓形成的危险因素,可被血小板清道夫受体CD36识别。oxLDL与CD36结合通过促进活性氧的产生来促进血小板活化和血栓形成。在这种情况下,由活性氧引发的下游信号事件尚不清楚。在本研究中,我们报告CD36信号传导促进血小板中的过氧化氢通量。使用选择性且共价修饰半胱氨酸亚磺酸的碳亲核试剂,我们发现通过CD36信号传导产生的过氧化氢促进血小板蛋白的半胱氨酸亚磺酰化。具体而言,Src家族激酶上的半胱氨酸被亚磺酰化,Src家族激酶是信号转导器,在识别其配体后被招募到CD36。半胱氨酸亚磺酰化促进了Src家族激酶的激活,并且通过使用CD36阻断抗体或通过过氧化氢的酶促降解而被阻止。一组亚磺酸选择性碳亲核试剂以浓度依赖性方式抑制CD36介导的血小板聚集和促凝磷脂酰丝氨酸外化。在相同浓度下,这些探针不抑制嘌呤能受体激动剂二磷酸腺苷或胶原受体糖蛋白VI激动剂胶原相关肽诱导的血小板聚集。用基于苯并噻嗪的亲核试剂在体内选择性修饰半胱氨酸亚磺酰化,可将血脂异常小鼠中增强的动脉血栓形成恢复到对照水平。这些发现表明,CD36信号传导产生过氧化氢以氧化血小板蛋白(包括Src家族激酶)中的半胱氨酸,并降低血脂异常中血小板活化的阈值。