title: The ABCC4 membrane transporter modulates platelet aggregation.
abstract: Controlling the activation of platelets is a key strategy to mitigate cardiovascular disease. Previous studies have suggested that the ATP-binding cassette (ABC) transporter, ABCC4, functions in platelet-dense granules. Using plasma membrane biotinylation and super-resolution microscopy, we demonstrate that ABCC4 is primarily expressed on the plasma membrane of both mouse and human platelets. Platelets lacking ABCC4 have unchanged dense-granule function, number, and volume, but harbor a selective impairment in collagen-induced aggregation. Accordingly, Abcc4 knockout (KO) platelet attachment to a collagen substratum was also faulty and associated with elevated intracellular cyclic AMP (cAMP) and reduced plasma membrane localization of the major collagen receptor, GPVI. In the ferric-chloride vasculature injury model, Abcc4 KO mice exhibited markedly impaired thrombus formation. The attenuation of platelet aggregation by the phosphodiesterase inhibitor EHNA (a non-ABCC4 substrate), when combined with Abcc4 deficiency, illustrated a crucial functional interaction between phosphodiesterases and ABCC4. This was extended in vivo where EHNA dramatically prolonged the bleeding time, but only in Abcc4 KO mice. Further, we demonstrated in human platelets that ABCC4 inhibition, when coupled with phosphodiesterase inhibition, strongly impaired platelet aggregation. These findings have important clinical implications because they directly highlight an important relationship between ABCC4 transporter function and phosphodiesterases in accounting for the cAMP-directed activity of antithrombotic agents.
authors.affiliation: Department of Pharmaceutical Sciences.
authors.forename: Satish B
authors.initials: SB
authors.lastname: Cheepala
authors.affiliation: Department of Pharmaceutical Sciences.
authors.forename: Aaron
authors.identifier: http://orcid.org/0000-0002-3017-2140
authors.initials: A
authors.lastname: Pitre
authors.affiliation: Department of Pharmaceutical Sciences.
authors.forename: Yu
authors.initials: Y
authors.lastname: Fukuda
authors.affiliation: Department of Pharmaceutical Sciences.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Takenaka
authors.affiliation: Department of Pharmaceutical Sciences.
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Department of Pharmaceutical Sciences.
authors.forename: Yao
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Cellular Imaging Shared Resource, and.
authors.forename: Sharon
authors.initials: S
authors.lastname: Frase
authors.affiliation: Department of Hematology, St. Jude Children's Research Hospital, Memphis, TN;
authors.forename: Tamara
authors.initials: T
authors.lastname: Pestina
authors.affiliation: Department of Biology, University of Memphis, Memphis, TN; and.
authors.forename: T Kent
authors.initials: TK
authors.lastname: Gartner
authors.affiliation: Academic Programs, St. Jude Children's Research Hospital, Memphis, TN.
authors.forename: Carl
authors.initials: C
authors.lastname: Jackson
authors.affiliation: Department of Pharmaceutical Sciences.
authors.forename: John D
authors.initials: JD
authors.lastname: Schuetz
mesh_terms: D000225:Adenine / Q000031:analogs & derivatives / Q000494:pharmacology; D000818:Animals; D001792:Blood Platelets / Q000378:metabolism* / Q000473:pathology; D000242:Cyclic AMP / Q000235:genetics / Q000378:metabolism; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000235:genetics / Q000378:metabolism; D010974:Platelet Aggregation; D013927:Thrombosis / Q000235:genetics / Q000378:metabolism / Q000473:pathology
chemical_list: D000225:Adenine; D000242:Cyclic AMP; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D010726:Phosphodiesterase Inhibitors; D010727:Phosphoric Diester Hydrolases; C073492:ABCC4 protein, human; C489540:Abcc4 protein, mouse; C010192:9-(2-hydroxy-3-nonyl)adenine