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dc.contributor.authorMillington-Burgess, Sarah L
dc.contributor.authorHarper, Matthew T
dc.date.accessioned2022-01-30T10:08:39Z
dc.date.available2022-01-30T10:08:39Z
dc.date.issued2022-04
dc.date.submitted2021-10-08
dc.identifier.issn1538-7933
dc.identifier.otherjth15641
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/333428
dc.description.abstractBACKGROUND: During thrombosis, procoagulant platelets expose phosphatidylserine (PS), which enhances local thrombin generation. Reducing platelet PS exposure could be a novel anti-thrombotic approach. PS is confined to the inner leaflet of the plasma membrane in unstimulated platelets by ATP-dependent "flippase" activity. Ca2+ ionophores trigger all platelets to expose a high level of PS by activating a scramblase protein and inactivating the flippase. Although R5421 was previously shown to reduce Ca2+ ionophore-induced PS exposure, its mechanism of action is unknown. OBJECTIVES: To determine the mechanism by which R5421 reduces platelet PS exposure. METHODS: Washed human platelets were stimulated with the Ca2+ ionophore, A23187, to induce procoagulant platelet formation while bypassing proximal receptor signalling. Platelets PS exposure was detected using annexin V or lactadherin in flow cytometry. NBD (7-nitro-2-1,3-benzoxadiazol-4-yl)-PS was used to assess scramblase and flippase activity. Thrombin generation was monitored using a fluorogenic substrate. RESULTS AND CONCLUSIONS: R5421 reduced the extent of A23187-stimulated platelet PS exposure, as demonstrated with annexin V or lactadherin binding. R5421 also maintained flippase activity in procoagulant platelets. Although R5421 appeared to inhibit scramblase activity in procoagulant platelets, it did not once the flippase had been inhibited, demonstrating that scramblase activity is not directly inhibited. Furthermore, R5421 inhibited the contribution of A23187-stimulated platelets to thrombin generation. Together these data demonstrate that R5421 reduces the extent of PS exposure in procoagulant platelets by maintaining flippase activity. Maintaining flippase activity in procoagulant platelets is a novel and effective approach to reducing thrombin generation.
dc.languageen
dc.publisherWiley
dc.subjectBRIEF REPORT
dc.subjectBRIEF REPORTS
dc.subjectblood platelets
dc.subjectpharmacology
dc.subjectphosphatidylserine
dc.subjectphospholipid transfer proteins
dc.subjectthrombosis
dc.titleMaintaining flippase activity in procoagulant platelets is a novel approach to reducing thrombin generation.
dc.typeOther
dc.date.updated2022-01-30T10:08:38Z
prism.publicationNameJ Thromb Haemost
dc.identifier.doi10.17863/CAM.80851
dcterms.dateAccepted2022-01-11
rioxxterms.versionofrecord10.1111/jth.15641
rioxxterms.versionAO
rioxxterms.versionVoR
rioxxterms.licenseref.urihttp://creativecommons.org/licenses/by/4.0/
dc.contributor.orcidMillington-Burgess, Sarah L [0000-0001-6549-920X]
dc.contributor.orcidHarper, Matthew T [0000-0002-4740-637X]
dc.identifier.eissn1538-7836
pubs.funder-project-idBritish Heart Foundation (PG/20/12/34982)
cam.issuedOnline2022-01-30


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