Novel Role for the AnxA1-Fpr2/ALX Signaling Axis as a Key Regulator of Platelet Function to Promote Resolution of Inflammation
Novel Role for the AnxA1-Fpr2/ALX Signaling Axis as a Key Regulator of Platelet Function to Promote Resolution of Inflammation
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DOI：
10.1161/circulationaha.118.039345
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发表时间：
2019-07-23
期刊：
影响因子：
37.8
通讯作者：
Gavins, Felicity N. E.
中科院分区：
文献类型：
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作者：
Senchenkova, Elena Y.;Ansari, Junaid;Gavins, Felicity N. E.
背景：缺血再灌注损伤(I/RI)是心血管疾病的常见并发症。消除由I/RI引起的有害的血栓前反应和炎症反应对于恢复体内平衡至关重要。血小板在血栓形成和炎症的整合中起着至关重要的作用。它们作为解决血栓炎症的参与者的作用被低估；因此，我们使用药理学和遗传学方法，结合小鼠和临床样本，来揭示这一作用的关键概念。方法：采用野生型或膜联蛋白A1(AnxA1)基因敲除(AnxA1(-/-))小鼠大脑中动脉闭塞再灌流模型。荧光活体显微镜被用来观察细胞的运输和监测光/染料诱导的血栓形成。分别用赋形剂、AnxA1(3.3 mg/kg)、WRW4(1.8 mg/kg)或ALL-3处理小鼠，观察AnxA1对小鼠的体内外作用。结果：活体显微镜显示I/RI后血小板黏附和聚集形成增加，在AnxA1(-/-)小鼠中进一步加剧。AnxA1通过直接调节血小板功能(如通过减少血栓素B-2和调节磷脂酰丝氨酸的表达)来促进I/RI后的脑保护，并通过减少血小板活化、聚集形成和脑血栓形成(缺血性中风的先决条件)而作为中风的有效预防策略。为了将这些发现转化到临床环境中，我们证明了AnxA1在人类和小鼠中风中的血浆水平降低，并且AnxA1能够作用于人类血小板，抑制经典的凝血酶诱导的内向外信号事件(例如Akt激活、细胞内钙释放和RAS相关蛋白1[Rap1]表达)，从而在不改变其表面表达的情况下减少α(IIb)β(3)的激活。AnxA1还选择性地修饰细胞表面决定因素(如磷脂酰丝氨酸)，以促进中性粒细胞对血小板的吞噬，从而推动主动分解。(n=5-13只/组或7-10人/组)。结论：AnxA1通过改变脑I/RI中的血小板表型，使其由致病状态变为调节型，并通过影响整合素(α(IIb)β(3))的激活来减少血小板聚集和导致血栓形成的倾向，这是一种以前未知的现象。因此，我们的数据揭示了AnxA1的一个新的多方面的作用，它通过促进脑I/RI中的内源性前分解、抗血栓炎症回路而同时作为治疗和预防药物发挥作用。总而言之，这些结果进一步促进了我们在血小板和分解生物学领域的知识和理解。
Background: Ischemia reperfusion injury (I/RI) is a common complication of cardiovascular diseases. Resolution of detrimental I/RI-generated prothrombotic and proinflammatory responses is essential to restore homeostasis. Platelets play a crucial part in the integration of thrombosis and inflammation. Their role as participants in the resolution of thromboinflammation is underappreciated; therefore we used pharmacological and genetic approaches, coupled with murine and clinical samples, to uncover key concepts underlying this role. Methods: Middle cerebral artery occlusion with reperfusion was performed in wild-type or annexin A1 (AnxA1) knockout (AnxA1(-/-)) mice. Fluorescence intravital microscopy was used to visualize cellular trafficking and to monitor light/dye-induced thrombosis. The mice were treated with vehicle, AnxA1 (3.3 mg/kg), WRW4 (1.8 mg/kg), or all 3, and the effect of AnxA1 was determined in vivo and in vitro. Results: Intravital microscopy revealed heightened platelet adherence and aggregate formation post I/RI, which were further exacerbated in AnxA1(-/-) mice. AnxA1 administration regulated platelet function directly (eg, via reducing thromboxane B-2 and modulating phosphatidylserine expression) to promote cerebral protection post-I/RI and act as an effective preventative strategy for stroke by reducing platelet activation, aggregate formation, and cerebral thrombosis, a prerequisite for ischemic stroke. To translate these findings into a clinical setting, we show that AnxA1 plasma levels are reduced in human and murine stroke and that AnxA1 is able to act on human platelets, suppressing classic thrombin-induced inside-out signaling events (eg, Akt activation, intracellular calcium release, and Ras-associated protein 1 [Rap1] expression) to decrease alpha(IIb)beta(3) activation without altering its surface expression. AnxA1 also selectively modifies cell surface determinants (eg, phosphatidylserine) to promote platelet phagocytosis by neutrophils, thereby driving active resolution. (n=5-13 mice/group or 7-10 humans/group.) Conclusions: AnxA1 affords protection by altering the platelet phenotype in cerebral I/RI from propathogenic to regulatory and reducing the propensity for platelets to aggregate and cause thrombosis by affecting integrin (alpha(IIb)beta(3)) activation, a previously unknown phenomenon. Thus, our data reveal a novel multifaceted role for AnxA1 to act both as a therapeutic and a prophylactic drug via its ability to promote endogenous proresolving, antithromboinflammatory circuits in cerebral I/RI. Collectively, these results further advance our knowledge and understanding in the field of platelet and resolution biology.