Disrupting the vicious cycle created by NOX activation in sickle erythrocytes exposed to hypoxia/reoxygenation prevents adhesion and vasoocclusion
Disrupting the vicious cycle created by NOX activation in sickle erythrocytes exposed to hypoxia/reoxygenation prevents adhesion and vasoocclusion
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DOI：
10.1016/j.redox.2019.101097
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发表时间：
2019-07-01
期刊：
影响因子：
11.4
通讯作者：
Zennadi, Rahima
中科院分区：
文献类型：
--
作者：
MacKinney, Anson;Woska, Emily;Zennadi, Rahima
在镰状细胞病（SCD）中，反复发作的疼痛性血管闭塞危象可能是由缺氧和复氧的反复发作引起的。镰状红细胞（SSRBC）粘附在血管阻塞中起积极作用。然而，缺氧应激后长时间复氧对SSRBC参与发作性血管闭塞的分子机制的影响仍不清楚。将人SSRBC暴露于缺氧，随后2 h复氧，增加了活性氧（ROS）的产生。使用特定的药理学抑制剂，我们表明，在网织红细胞和成熟的SSRBC中的过量ROS的产生是由NADPH氧化酶（NOX），丝裂原活化蛋白激酶（ERK 1/2）和G-蛋白偶联受体激酶2（GRK 2）调节。因此，SSRBC ROS与ERK 1/2和GRK 2形成细胞内正反馈回路，以在体外介导SSRBC与内皮的粘附，并在体内介导小鼠血管闭塞模型中的血管闭塞。重要的是，用氧化还原活性锰（Mn）卟啉（通常称为超氧化物歧化酶（SOD）的模拟物）降低SSRBC中的ROS水平，通过影响NOX和GRK 2活性以及ERK 1/2磷酸化来破坏ROS产生的循环，从而消除RBC-内皮相互作用。粘附抑制实验表明，LW（ICAM-4，CD 242）血型糖蛋白和CD 44是介导内皮细胞结合的红细胞粘附分子。相反，正常RBC的缺氧/复氧未能激活这种反馈回路和粘附。这些研究结果提供了新的见解的病理生理学意义的有害循环所产生的NOx依赖性的ROS，GRK 2和ERK 1/2的SSRBC缺氧/复氧激活，并参与SSRBC粘附和血管闭塞。因此，SSRBC中的这种环可以被Mn卟啉破坏，可能驱动严重的SCD血管病变，并可能指向新的治疗靶点以预防慢性血管闭塞事件。
In sickle cell disease (SCD), recurrent painful vasoocclusive crisis are likely caused by repeated episodes of hypoxia and reoxygenation. The sickle erythrocyte (SSRBC) adhesion plays an active role in vasoocclusion. However, the effect of prolonged reoxygenation after hypoxic stress on the molecular mechanisms in SSRBCs involved in onset of episodic vasoocclusion remain unclear. Exposure of human SSRBCs to hypoxia followed by 2 h reoxygenation, increased reactive oxygen species (ROS) production. Using specific pharmacological inhibitors, we show that excess ROS production in both reticulocytes and mature SSRBCs is regulated by NADPH oxidases (NOXs), the mitogen-activated protein kinase (ERK1/2), and G-protein coupled-receptor kinase 2 (GRK2). Consequently, SSRBC ROS create an intracellular positive feedback loop with ERK1/2 and GRK2 to mediate SSRBC adhesion to endothelium in vitro, and vasoocclusion in a mouse model of vasoocclusion in vivo. Importantly, reducing ROS levels in SSRBCs with redox-active manganese (Mn) porphyrins, commonly known as mimics of superoxide dismutase (SOD), disrupted the cycle created by ROS by affecting NOX and GRK2 activities and ERK1/2 phosphorylation, thus abrogating RBC-endothelial interactions. Inhibition adhesion assays show that LW (ICAM-4, CD242) blood group glycoprotein and CD44 are the RBC adhesion molecules mediating endothelial binding. Conversely, hypoxia/reoxygenation of normal RBCs failed to activate this feedback loop, and adhesion. These findings provide novel insights into the pathophysiological significance of the deleterious cycle created by NOX-dependent ROS, GRK2 and ERK1/2 within SSRBCs activated by hypoxia/reoxygenation, and involved in SSRBC adhesion and vasoocclusion. Thus, this loop in SSRBCs, which can be disrupted by Mn porphyrins, likely drives the profound SCD vasculopathy, and may point to new therapeutic targets to prevent chronic vasoocclusive events.