Kim Kyungho, Li Jing, Tseng Alan, Andrews Robert K, Cho Jaehyung
Department of Pharmacology and.
Department of Pharmacology and Department of Anesthesiology, University of Illinois College of Medicine, Chicago, IL; and.
Blood. 2015 Oct 15;126(16):1952-64. doi: 10.1182/blood-2014-10-605261. Epub 2015 Sep 2.
Platelet-leukocyte interactions on activated endothelial cells play an important role during microvascular occlusion under oxidative stress conditions. However, it remains poorly understood how neutrophil-platelet interactions are regulated during vascular inflammation. By using intravital microscopy with mice lacking nicotinamide adenine dinucleotide phosphate (NADPH) oxidase 2 (NOX2) and their bone marrow chimera, we demonstrated that NOX2 from both hematopoietic and endothelial cells is crucial for neutrophil-platelet interactions during tumor necrosis factor alpha-induced venular inflammation. Platelet NOX2-produced reactive oxygen species (ROS) regulated P-selectin exposure upon agonist stimulation and the ligand-binding function of glycoprotein Ibα. Furthermore, neutrophil NOX2-generated ROS enhanced the activation and ligand-binding activity of αMβ2 integrin following N-formyl-methionyl-leucyl phenylalanine stimulation. Studies with isolated cells and a mouse model of hepatic ischemia/reperfusion injury revealed that NOX2 from both platelets and neutrophils is required for cell-cell interactions, which contribute to the pathology of hepatic ischemia/reperfusion injury. Platelet NOX2 modulated intracellular Ca(2+) release but not store-operated Ca(2+) entry (SOCE), whereas neutrophil NOX2 was crucial for SOCE but not intracellular Ca(2+) release. Different regulation of Ca(2+) signaling by platelet and neutrophil NOX2 correlated with differences in the phosphorylation of AKT, ERK, and p38MAPK. Our results indicate that platelet and neutrophil NOX2-produced ROS are critical for the function of surface receptors essential for neutrophil-platelet interactions during vascular inflammation.
在氧化应激条件下，活化内皮细胞上的血小板-白细胞相互作用在微血管闭塞过程中起重要作用。然而，在血管炎症期间中性粒细胞-血小板相互作用是如何被调节的，目前仍知之甚少。通过对缺乏烟酰胺腺嘌呤二核苷酸磷酸（NADPH）氧化酶2（NOX2）的小鼠及其骨髓嵌合体进行活体显微镜观察，我们证明，在肿瘤坏死因子α诱导的小静脉炎症过程中，造血细胞和内皮细胞中的NOX2对于中性粒细胞-血小板相互作用至关重要。血小板中由NOX2产生的活性氧（ROS）在激动剂刺激后调节P-选择素的暴露以及糖蛋白Ibα的配体结合功能。此外，中性粒细胞中由NOX2产生的ROS在N-甲酰甲硫氨酰-亮氨酰-苯丙氨酸刺激后增强了αMβ2整合素的活化和配体结合活性。对分离细胞和肝缺血/再灌注损伤小鼠模型的研究表明，血小板和中性粒细胞中的NOX2都是细胞间相互作用所必需的，而这种相互作用会导致肝缺血/再灌注损伤的病理过程。血小板中的NOX2调节细胞内Ca(2+)释放，但不调节储存式Ca(2+)内流（SOCE），而中性粒细胞中的NOX2对SOCE至关重要，但对细胞内Ca(2+)释放则不然。血小板和中性粒细胞中的NOX2对Ca(2+)信号的不同调节与AKT、ERK和p38MAPK磷酸化的差异相关。我们的结果表明，在血管炎症期间，血小板和中性粒细胞中由NOX2产生的ROS对于中性粒细胞-血小板相互作用所必需的表面受体功能至关重要。
