Aquaporin-1 regulates platelet procoagulant membrane dynamics and in vivo thrombosis

• DOI: 10.1172/jci.insight.99062
• Publication Date: 2018-05-16T15:00:54Z
• Authors: Ejaife O. Agbani; Christopher M. Wi...; Yong Li; Marion T.J. van d...; Samantha F. Moore; Adele Mauroux; Lorna Hodgson; Alan S. Verkman; Ingeborg Hers; Alastair W. Poole
• Keywords: Platelets; Blood Platelets; Biomedical and clinical sciences; /dk/atira/pure/core/keywords/brissynbio; name=BrisSynBio; 1.1 Normal biological development and functioning; Knockout; Medical Physiology; 610; aquaporin-1; /dk/atira/pure/core/keywords/biodesign_SRI; procoagulant-spreading; Cardiovascular; name=BrisSynBio; Mice; 03 medical and health sciences; mechanosensitive cation channels; Underpinning research; membrane ballooning; 2.1 Biological and endogenous factors; Animals; Humans; Aetiology; Synthetic biology; Mice, Knockout; 0303 health sciences; Coagulation; Biomedical and Clinical Sciences; Aquaporin 1; Coagulants; Cell Membrane; Health sciences; Transient receptor potential isoform C1 (TRPC1) and C6 (TRPC6); Thrombosis; Hematology; Cell Biology; Water channel; Blood; piezo1; /dk/atira/pure/core/keywords/brissynbio; name=Bristol BioDesign Institute; /dk/atira/pure/core/keywords/biodesign_SRI; name=Bristol BioDesign Institute; Research Article; Subcellular Fractions

In response to collagen stimulation, platelets use a coordinated system of fluid entry to undergo membrane ballooning, procoagulant spreading, and microvesiculation. We hypothesized that water entry was mediated by the water channel aquaporin-1 (AQP1) and aimed to determine its role in the platelet procoagulant response and thrombosis. We established that human and mouse platelets express AQP1 and localize to internal tubular membrane structures. However, deletion of AQP1 had minimal effects on collagen-induced platelet granule secretion, aggregation, or membrane ballooning. Conversely, procoagulant spreading, microvesiculation, phosphatidylserine exposure, and clot formation time were significantly diminished. Furthermore, in vivo thrombus formation after FeCl3 injury to carotid arteries was also markedly suppressed in AQP1-null mice, but hemostasis after tail bleeding remained normal. The mechanism involves an AQP1-mediated rapid membrane stretching during procoagulant spreading but not ballooning, leading to calcium entry through mechanosensitive cation channels and a full procoagulant response. We conclude that AQP1 is a major regulator of the platelet procoagulant response, able to modulate coagulation after injury or pathologic stimuli without affecting other platelet functional responses or normal hemostasis. Clinically effective AQP1 inhibitors may therefore represent a novel class of antiprocoagulant antithrombotics.