Dataset Information

Reactive oxygen species play a critical role in collagen-induced platelet activation via SHP-2 oxidation.

ABSTRACT:

Aims

The collagen-stimulated generation of reactive oxygen species (ROS) regulates signal transduction in platelets, although the mechanism is unclear. The major targets of ROS include protein tyrosine phosphatases (PTPs). ROS-mediated oxidation of the active cysteine site in PTPs abrogates the PTP catalytic activity. The aim of this study was to elucidate whether collagen-induced ROS generation leads to PTP oxidation, which promotes platelet stimulation.

Results

SH2 domain-containing PTP-2 (SHP-2) is oxidized in platelets by ROS produced upon collagen stimulation. The oxidative inactivation of SHP-2 leads to the enhanced tyrosine phosphorylation of spleen tyrosine kinase (Syk), Vav1, and Bruton's tyrosine kinase (Btk) in the linker for the activation of T cells signaling complex, which promotes the tyrosine phosphorylation-mediated activation of phospholipase C?2 (PLC?2). Moreover, we found that, relative to wild-type platelets, platelets derived from glutathione peroxidase 1 (GPx1)/catalase double-deficient mice showed enhanced cellular ROS levels, oxidative inactivation of SHP-2, and tyrosine phosphorylation of Syk, Vav1, Btk, and PLC?2 in response to collagen, which subsequently led to increased intracellular calcium levels, degranulation, and integrin ?IIb?3 activation. Consistent with these findings, GPx1/catalase double-deficiency accelerated the thrombotic response in FeCl3-injured carotid arteries.

Innovation

The present study is the first to demonstrate that SHP-2 is targeted by ROS produced in collagen-stimulated platelets and suggests that a novel mechanism for the regulation of platelet activation by ROS is due to oxidative inactivation of SHP-2.

Conclusion

We conclude that collagen-induced ROS production leads to SHP-2 oxidation, which promotes platelet activation by upregulating tyrosine phosphorylation-based signal transduction.

SUBMITTER: Jang JY

PROVIDER: S-EPMC4025609 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature

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Publications

Reactive oxygen species play a critical role in collagen-induced platelet activation via SHP-2 oxidation.

Jang Ji Yong JY Min Ji Hyun JH Chae Yun Hee YH Baek Jin Young JY Wang Su Bin SB Park Su Jin SJ Oh Goo Taeg GT Lee Sang-Hak SH Ho Ye-Shih YS Chang Tong-Shin TS

Antioxidants & redox signaling 20140130 16

<h4>Aims</h4>The collagen-stimulated generation of reactive oxygen species (ROS) regulates signal transduction in platelets, although the mechanism is unclear. The major targets of ROS include protein tyrosine phosphatases (PTPs). ROS-mediated oxidation of the active cysteine site in PTPs abrogates the PTP catalytic activity. The aim of this study was to elucidate whether collagen-induced ROS generation leads to PTP oxidation, which promotes platelet stimulation.<h4>Results</h4>SH2 domain-contai ...[more]

PMID: 24093153

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Project description:Essentials Reactive oxygen species (ROS) generation by NOX2 plays a critical role in platelet activation. Rac1 regulation of NOX2 is important for ROS generation. Small molecule inhibitor of the Rac1-p67phox interaction prevents platelet activation. Pharmacologic targeting of Rac1-NOX2 axis can be a viable approach for antithrombotic therapy.SummaryBackground Platelets from patients with X-linked chronic granulomatous disease or mice deficient in nicotinamide adenine dinucleotide (phosphate) (NAD(P)H) oxidase isoform NOX2 exhibit diminished reactive oxygen species (ROS) generation and platelet activation. Binding of Rac1 GTPase to p67phox plays a critical role in NOX2 activation by facilitating the assembly of the NOX2 enzyme complex. Objective We tested the hypothesis that Phox-I, a rationally designed small molecule inhibitor of Rac-p67phox interaction, may serve as an antithrombosis agent by suppressing ROS production and platelet activation. Results Collagen-related peptide (CRP) induced ROS generation in a time-dependent manner. Platelets from Rac1-/- mice or human platelets treated with NSC23766, a specific Rac inhibitor, produced significantly less ROS in response to CRP. Treatment of platelets with Phox-I inhibited diverse CRP-induced responses, including: (i) ROS generation; (ii) release of P-selectin; (iii) secretion of ATP; (iv) platelet aggregation; and (v) phosphorylation of Akt. Similarly, incubation of platelets with Phox-I inhibited thrombin-induced: (i) secretion of ATP; (ii) platelet aggregation; (iii) rise in cytosolic calcium; and (iv) phosphorylation of Akt. In mouse models, intraperitoneal administration of Phox-I inhibited: (i) collagen-induced platelet aggregation without affecting the tail bleeding time and (ii) in vivo platelet adhesion/accumulation at the laser injury sites on the saphenous vein without affecting the time for complete cessation of blood loss. Conclusions Small molecule targeting of the Rac1-p67phox interaction may present an antithrombosis regimen by preventing GPVI- and non-GPVI-mediated NOX2 activation, ROS generation and platelet function without affecting the bleeding time.

Dataset Information

Reactive oxygen species play a critical role in collagen-induced platelet activation via SHP-2 oxidation.

Aims

Results

Innovation

Conclusion

Publications

Reactive oxygen species play a critical role in collagen-induced platelet activation via SHP-2 oxidation.

Similar Datasets

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