ARF6-Dependent Regulation of P2Y Receptor Traffic and Function in Human Platelets

Kanamarlapudi, Venkateswarlu; Owens, Siân-Eleri; Saha, K. C.; Pope, Robert J P; Mundell, Stuart J

doi:10.1371/journal.pone.0043532

Cited by 31 publications

(19 citation statements)

References 37 publications

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“…Genetic ablation of Arf6 in platelets enhanced clot retraction and spreading, indicating that endocytosis contributes to rapid platelet functions. These findings are consistent with Kanamarlapudi and colleagues who showed that Arf6 regulates P2Y trafficking in platelets as well as dynamin-dependent fission of coated vesicles during endocytosis[50]. Additionally, two Rab proteins (Rab4 and Rab11) are also involved in integrin-mediated fibrinogen uptake and trafficking in platelets[49, 51].…”

Section: Granular Secretion Mechanisms In Plateletssupporting

confidence: 87%

Platelet secretion in inflammatory and infectious diseases

2016

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Platelets are small, anucleate circulating cells that possess a dynamic repertoire of functions spanning the hemostatic, inflammatory, and immune continuum. Once thought to be merely cell fragments with responses limited primarily to acute hemostasis and vascular wall repair, platelets are now increasingly recognized as key sentinels and effector cells regulating host responses to many inflammatory and infectious cues. Platelet granules, including α-granules and dense-granules, store hundreds of factors and secrete these mediators in response to activating signals. The cargo packaged and stored within platelet granules orchestrates communication between platelets and other circulating cells, augments host defense mechanisms to invading pathogens and tumor cells, and – in some settings - drives dysregulated and injurious responses. This focused review will highlight several of the established and emerging mechanisms and roles of platelet secretion in inflammatory and infectious diseases.

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Section: Granular Secretion Mechanisms In Plateletssupporting

confidence: 87%

Platelet secretion in inflammatory and infectious diseases

2016

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“…12 Arf6 also appears to play a role in the endocytosis and resensitization of P2Y receptors. 14 Taken together, these data suggest that Arf6 controls endocytic trafficking in a manner that may be responsive to both initial platelet activation and subsequent signaling from contactmediated pathways. The goal of this study was to further understand the action of Arf6 in platelets.…”

Section: Introductionmentioning

confidence: 73%

Arf6 controls platelet spreading and clot retraction via integrin αIIbβ3 trafficking

Huang¹,

Joshi²,

Xiang

et al. 2016

Blood

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• Arf6 selectively regulates endocytic trafficking of platelet a IIb b 3 .• Endocytosis contributes to acute platelet function.Platelet and megakaryocyte endocytosis is important for loading certain granule cargo (ie, fibrinogen [Fg] and vascular endothelial growth factor); however, the mechanisms of platelet endocytosis and its functional acute effects are understudied. Adenosine 5'-diphosphate-ribosylation factor 6 (Arf6) is a small guanosine triphosphate-binding protein that regulates endocytic trafficking, especially of integrins. To study platelet endocytosis, we generated platelet-specific Arf6 knockout (KO) mice. Arf6 KO platelets had less associated Fg suggesting that Arf6 affects a IIb b 3 -mediated Fg uptake and/or storage. Other cargo was unaffected. To measure Fg uptake, mice were injected with biotinylated-or fluorescein isothiocyanate (FITC)-labeled Fg. Platelets from the injected Arf6 KO mice showed lower accumulation of tagged Fg, suggesting an uptake defect. Ex vivo, Arf6 KO platelets were also defective in FITC-Fg uptake and storage. Immunofluorescence analysis showed initial trafficking of FITC-Fg to a Rab4-positive compartment followed by colocalization with Rab11-positive structures, suggesting that platelets contain and use both early and recycling endosomes. Resting and activated a IIb b 3 levels, as measured by flow cytometry, were unchanged; yet, Arf6 KO platelets exhibited enhanced spreading on Fg and faster clot retraction. This was not the result of alterations in a IIb b 3 signaling, because myosin light-chain phosphorylation and Rac1/RhoA activation were unaffected. Consistent with the enhanced clot retraction and spreading, Arf6 KO mice showed no deficits in tail bleeding or FeCl 3 -induced carotid injury assays. Our studies present the first mouse model for defining the functions of platelet endocytosis and suggest that altered integrin trafficking may affect the efficacy of platelet function. (Blood. 2016;127(11):1459-1467 IntroductionIt is increasingly clear that platelets are capable of different types of intracellular membrane trafficking. Platelet exocytosis and autophagy are critical for hemostasis. [1][2][3][4] Platelet endocytosis is important for granule cargo loading. Platelets selectively take up certain cargo (ie, fibrinogen [Fg] and vascular endothelial growth factor) from plasma and package it into a-granules. [5][6][7][8] However, the molecular mechanisms of platelet endocytosis are largely unknown. It is also unclear whether platelet endocytosis contributes to acute platelet functions beyond granule cargo loading. The goal of this study is to begin to address these fundamental questions.The Ras-like, small guanosine triphosphate (GTP)-binding proteins called adenosine 5'-diphosphate-ribosylation factors (Arf's), are key intracellular trafficking regulators. They cycle between inactive guanosine diphosphate (GDP)-bound and active GTP-bound states and are important for multiple functions (eg, actin cytoskeleton remodeling, lipid metabolism, and vesicle traffickin...

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“…In another paper, it was claimed that both P2Y 1 -and P2Y 12 -mediated platelet responses desensitise rapidly, but by different kinase-dependent mechanisms [247]. The desensitization of the P2Y receptor on platelets requires receptor internalization, and it was claimed that the GTP-binding protein ADP ribosylation factor 6 is required for P2Y receptor internalization [248].…”

Section: Pathologymentioning

confidence: 99%

Blood cells: an historical account of the roles of purinergic signalling

Burnstock

2015

Purinergic Signalling

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The involvement of purinergic signalling in the physiology of erythrocytes, platelets and leukocytes was recognised early. The release of ATP and the expression of purinoceptors and ectonucleotidases on erythrocytes in health and disease are reviewed. The release of ATP and ADP from platelets and the expression and roles of P1, P2Y 1 , P2Y 12 and P2X1 receptors on platelets are described. P2Y 1 and P2X1 receptors mediate changes in platelet shape, while P2Y 12 receptors mediate platelet aggregation. The changes in the role of purinergic signalling in a variety of disease conditions are considered. The successful use of P2Y 12 receptor antagonists, such as clopidogrel and ticagrelor, for the treatment of thrombosis, myocardial infarction and stroke is discussed.

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ARF6-Dependent Regulation of P2Y Receptor Traffic and Function in Human Platelets

Cited by 31 publications

References 37 publications

Platelet secretion in inflammatory and infectious diseases

Platelet secretion in inflammatory and infectious diseases

Arf6 controls platelet spreading and clot retraction via integrin αIIbβ3 trafficking

Blood cells: an historical account of the roles of purinergic signalling

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