Platelet Shape Change and Spreading

Aslan, Joseph E.; Itakura, Asako; Gertz, Jacqueline M.; McCarty, Owen J. T.

doi:10.1007/978-1-61779-307-3_7

Cited by 75 publications

(64 citation statements)

References 14 publications

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“…Inhibitors or vehicle was added to platelets in solution at the indicated concentrations for 10 min prior to stimulation at 37°C and fixation. Platelets were imaged using Köhler illuminated Nomarski differential interference contrast (DIC) optics with a Zeiss ϫ63 oil immersion 1.40 numerical aperture (NA) plan-apochromat lens on a Zeiss Axiovert 200M microscope as previously described (3,6).…”

Section: Methodsmentioning

confidence: 99%

Histone deacetylase 6-mediated deacetylation of α-tubulin coordinates cytoskeletal and signaling events during platelet activation

Aslan

Phillips

Healy

et al. 2013

American Journal of Physiology-Cell Physiology

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Aslan JE, Phillips KG, Healy LD, Itakura A, Pang J, McCarty OJ. Histone deacetylase 6-mediated deacetylation of ␣-tubulin coordinates cytoskeletal and signaling events during platelet activation. Am J Physiol Cell Physiol 149: C1230 -C1239, 2013. First published September 11, 2013; doi:10.1152/ajpcell.00053.2013.-The tubulin cytoskeleton plays a key role in maintaining the characteristic quiescent discoid shape of resting platelets. Upon activation, platelets undergo a dramatic change in shape; however, little is known of how the microtubule system contributes to regulating platelet shape and function. Here we investigated the role of the covalent modification of ␣-tubulin by acetylation in the regulation of platelet physiology during activation. Superresolution microscopy analysis of the platelet tubulin cytoskeleton showed that the marginal band together with an interconnected web of finer tubulin structures collapsed upon platelet activation with the glycoprotein VI (GPVI)-agonist collagen-related peptide (CRP). Western blot analysis revealed that ␣-tubulin was acetylated in resting platelets and deacetylated during platelet activation. Tubacin, a specific inhibitor of the tubulin deacetylase HDAC6, prevented tubulin deacetylation upon platelet activation with CRP. Inhibition of HDAC6 upregulated tubulin acetylation and disrupted the organization of the platelet microtubule marginal band without significantly affecting platelet volume changes in response to CRP stimulation. HDAC6 inhibitors also inhibited platelet aggregation in response to CRP and blocked platelet signaling events upstream of platelet Rho GTPase activation. Together, these findings support a role for acetylation signaling in controlling the resting structure of the platelet tubulin marginal band as well as in the coordination of signaling systems that drive platelet cytoskeletal changes and aggregation. acetylation; HDAC6; platelets; tubulin PLATELETS ARE THE PRIMARY cellular mediators of hemostasis (13,18,32). As discoid cellular fragments formed from the appendages of megakaryocytes, platelets patrol the circulation as guardians of vascular integrity. When platelets detect signals of vessel damage, they adhere to subendothelial matrix proteins, activate and aggregate with other platelets to potentiate thrombus formation to stem the leakage of blood. During this process, platelets change shape from discs to irregularly shaped spheres with finger-like pseudopods and form lamellipodial sheets to facilitate spreading. The characterization of the molecular and cellular regulators of platelet cytoskeletal organization will provide a better understanding of the role that changes in platelet morphology upon activation play in platelet physiology and function.The discoid shape of quiescent platelets is maintained by a circumferential marginal band of microtubules that scaffolds the platelet inner periphery (44). This marginal band is made up of multiple dynamic, continually polymerizing tubulin coils of mixed polarity (31). During platelet activati...

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Section: Methodsmentioning

confidence: 99%

Histone deacetylase 6-mediated deacetylation of α-tubulin coordinates cytoskeletal and signaling events during platelet activation

Aslan

Phillips

Healy

et al. 2013

American Journal of Physiology-Cell Physiology

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“…[21] Unstimulated platelets isolated from healthy donors bound to immobilized fibrinogen and formed filopodia-like protrusions within an hour (top left panels of Figure 1C and D), while platelets stimulated by 10 µM adenosine diphosphate (ADP) (bottom left panels of Figure 1C and D) or 1.6 U/mL thrombin (not shown) spread fully on the surface. Interestingly, treatment with 200 µM indothiazinone dramatically inhibited the ADP-induced platelet spreading (bottom right panels of Figure 1C and D).…”

Section: Identification Of Indothiazinone As a Natural Antiplatelet Amentioning

confidence: 96%

Identification of indothiazinone as a natural antiplatelet agent

et al. 2017

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Cardiovascular disease, which is caused by unregulated platelet aggregation, is one of the main causes of deaths worldwide. Many studies have focused on natural products with antiplatelet effects as a safe alternative therapy to prevent the disease. In this context, an in-house chemical library was screened to find natural products capable of inhibiting the interaction between platelet integrin αIIbβ3 and fibrinogen, which is an essential step in platelet aggregation. On the basis of the screening results, indothiazinone, an alkaloid found in microbial cultures, was identified as a potential antiplatelet agent. Specifically, indothiazinone treatment significantly inhibited the binding of fibrinogen to Chinese hamster ovary cells expressing integrin αIIbβ3. It also restricted thrombin- and adenosine diphosphate-dependent spreading of human platelets on a fibrinogen matrix. More importantly, surface plasmon resonance and molecular dynamics studies suggested that indothiazinone suppressed talin-induced activation of integrin αIIbβ3 presumably by inhibiting talin-integrin interaction. In conclusion, these results suggest that indothiazinone can be used as a lead compound for the development of antiplatelet drugs with a novel mode of action.

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“…18 Platelets were stimulated with 0.5 U/mL thrombin and 2 mM A23187 for 15 minutes at 37°C. Subsequently, 10 U/mL hirudin was added to neutralize thrombin.…”

Section: Purification Of Human Washed Plateletsmentioning

confidence: 99%

Activated factor XI increases the procoagulant activity of the extrinsic pathway by inactivating tissue factor pathway inhibitor

Puy

Tucker

Matafonov

et al. 2015

Blood

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• Activated factor XI binds and proteolyzes tissue factor pathway inhibitor.• Activated factor XI promotes factor X activation generation and fibrin formation through the inactivation of tissue factor pathway inhibitor from platelets and on endothelial cells.Activation of coagulation factor XI (FXI) may play a role in hemostasis. The primary substrate of activated FXI (FXIa) is FIX, leading to FX activation (FXa) and thrombin generation. However, recent studies suggest the hemostatic role of FXI may not be restricted to the activation of FIX. We explored whether FXI could interact with and inhibit the activity of tissue factor pathway inhibitor (TFPI). TFPI is an essential reversible inhibitor of activated factor X (FXa) and also inhibits the FVIIa-TF complex. We found that FXIa neutralized both endothelium-and platelet-derived TFPI by cleaving the protein between the Kunitz (K) 1 and K2 domains (Lys86/Thr87) and at the active sites of the K2 (Arg107/Gly108) and K3 (Arg199/Ala200) domains. Addition of FXIa to plasma was able to reverse the ability of TFPI to prolong TF-initiated clotting times in FXI-or FIX-deficient plasma, as well as FXa-initiated clotting times in FX-deficient plasma. Treatment of cultured endothelial cells with FXIa increased the generation of FXa and promoted TF-dependent fibrin formation in recalcified plasma. Together, these results suggest that the hemostatic role of FXIa may be attributed not only to activation of FIX but also to promoting the extrinsic pathway of thrombin generation through inactivation of TFPI.

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Platelet Shape Change and Spreading

Cited by 75 publications

References 14 publications

Histone deacetylase 6-mediated deacetylation of α-tubulin coordinates cytoskeletal and signaling events during platelet activation

Histone deacetylase 6-mediated deacetylation of α-tubulin coordinates cytoskeletal and signaling events during platelet activation

Identification of indothiazinone as a natural antiplatelet agent

Activated factor XI increases the procoagulant activity of the extrinsic pathway by inactivating tissue factor pathway inhibitor

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