LRRC8 complexes are ATP release channels regulating platelet activation and arterial thrombosis Open Access

• Platelet LRRC8 channel complexes are ATP release channels which amplify platelet function and thrombosis

• Pharmacological inhibition of LRRC8 complexes impairs platelet function, thus identifying LRRC8 complexes as a novel anti-thrombotic target

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, 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 affecting bleeding times. Mechanistically, platelet LRRC8A mediates swell-induced cytosolic ATP release to amplify agonist-stimulated calcium-PI3K-AKT 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 anti-thrombotic drug target.