Tranter John D, Mikami Ryan T, Kumar Ashutosh, Brown Gavriel, Abd El-Aziz Tarek Mohamed, Zhao Yonghui, Arullampalam Prakash, Ashworth Katrina, Jha Vishwanath, Abraham Nihil, Meyer Chloe, Ajanel Abigail, Xie Litao, Feng Yongmei, Hong Juan, Zhang Haixia, Kumari Tripti, Balutowski Adam, Liu Alice, Bark David, Nair Vinayak K, Lasky Nina M, Stitziel Nathan O, Lerner Daniel J, Campbell Robert A, Di Paola Jorge, Cho Jaehyung, Sah Rajan
Cardiovascular Division, Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO.
Division of Hematology, Department of Medicine, Washington University School of Medicine, St. Louis, MO.
Blood. 2025 Aug 28;146(9):1110-1126. doi: 10.1182/blood.2024026667.
Platelet shape and volume changes are early mechanical events contributing to platelet activation and thrombosis. Here, we identify single-nucleotide polymorphisms in leucine-rich repeat-containing 8 (LRRC8) protein subunits that form the volume-regulated anion channel (VRAC), which are independently associated with altered mean platelet volume. LRRC8A is required for functional VRAC in megakaryocytes (MKs) and regulates platelet volume; adhesion; and agonist-stimulated activation, aggregation, adenosine triphosphate (ATP) secretion, and calcium mobilization. MK-specific LRRC8A conditional knockout mice have reduced laser injury-induced cremaster arteriolar thrombus formation and prolonged FeCl3 induced carotid arterial thrombosis without prolonged bleeding times. Mechanistically, platelet LRRC8A mediates swell-induced cytosolic ATP release to amplify agonist-stimulated calcium-phosphoinositide 3-kinase-protein kinase B signaling. Small-molecule LRRC8 channel inhibitors recapitulate defects observed in LRRC8A-null platelets in vitro and in vivo. These studies identify the mechanoresponsive LRRC8 channel complex as an ATP release channel in platelets, which positively regulates platelet function and thrombosis, providing a proof of concept for a novel antithrombotic drug target.
血小板形状和体积变化是导致血小板活化和血栓形成的早期机械事件。在此，我们鉴定了富含亮氨酸重复序列8（LRRC8）蛋白亚基中的单核苷酸多态性，这些亚基构成了容积调节性阴离子通道（VRAC），它们与平均血小板体积改变独立相关。LRRC8A是巨核细胞（MKs）中功能性VRAC所必需的，并调节血小板体积、黏附以及激动剂刺激的活化、聚集、三磷酸腺苷（ATP）分泌和钙动员。MK特异性LRRC8A条件性敲除小鼠激光损伤诱导的提睾肌小动脉血栓形成减少，FeCl3诱导的颈动脉血栓形成时间延长，但出血时间未延长。从机制上讲，血小板LRRC8A介导肿胀诱导的胞质ATP释放，以放大激动剂刺激的钙-磷脂酰肌醇3激酶-蛋白激酶B信号传导。小分子LRRC8通道抑制剂在体外和体内重现了LRRC8A基因缺失血小板中观察到的缺陷。这些研究确定了机械反应性LRRC8通道复合物作为血小板中的ATP释放通道，其正向调节血小板功能和血栓形成，为新型抗血栓药物靶点提供了概念验证。
