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Updated: May 16, 2025
Author Spotlight: Innovative Techniques for ROS Detection and Implications for Platelet Research
Published on: March 29, 2024
Targeting NADPH Oxidase with APX-115: Suppression of Platelet Activation and Thrombotic Response
Joara Jang1, Hyunseong Yu1, Eun Bee Oh1
1College of Pharmacy, Seoul National University, Seoul, Republic of Korea.
Abstract:
Aims: NADPH oxidase (NOX)-derived reactive oxygen species (ROS) are critical for platelet activation and thrombus formation. We hypothesized that inhibiting NOX-mediated ROS production with a pan-NOX inhibitor, APX-115, could effectively suppress platelet activation and thrombus formation, potentially serving as a novel antiplatelet therapeutic. This study aimed to explore the effects of APX-115 on human platelet functional responses and ROS-mediated signaling pathways. Results: APX-115 inhibited intracellular and extracellular ROS production in collagen-stimulated platelets, suppressing aggregation, P-selectin exposure, and ATP release. By preserving protein tyrosine phosphatase activity, APX-115 reduced tyrosine phosphorylation-dependent pathways inhibition, including spleen tyrosine kinase, LAT, Vav1, Bruton's tyrosine kinase, and phospholipase Cγ2, leading to decreased PKC activation and calcium mobilization. APX-115 also suppressed collagen-induced integrin αIIbβ3 activation, accompanied by elevated cGMP and vasodilator-stimulated phosphoprotein phosphorylation levels. In addition, APX-115 reduced p38 MAPK and ERK5 activation, leading to diminished phospholipase A2 phosphorylation, thromboxane production, and the exposure of procoagulant phosphatidylserine. These inhibitory effects extended to thrombus development caused by platelet adherence under shear and arterial thrombosis without prolonging bleeding time in murine models. Innovation: This study is the first to demonstrate that APX-115 inhibits NOX-mediated ROS production, platelet activation, and thrombus formation. By uncovering its effects on collagen receptor glycoprotein VI-mediated pathways, the work highlights the promise of APX-115 as an antiplatelet and antithrombotic agent. Conclusion: Our findings highlight the therapeutic potential of APX-115 in treating thrombotic and cardiovascular disorders by targeting NOX-mediated ROS production to mitigate platelet hyperreactivity and thrombus formation. Antioxid. Redox Signal. 43, 288-307.
Insights
The novel pan-NOX inhibitor APX-115 effectively suppresses platelet activation and thrombus formation by reducing NADPH oxidase-derived reactive oxygen species (ROS). This research highlights APX-115 as a promising antiplatelet and antithrombotic therapeutic agent.
Area of Science:
- Biochemistry
- Pharmacology
- Cardiovascular Research
Background:
- NADPH oxidase (NOX)-derived reactive oxygen species (ROS) are crucial for platelet activation and thrombus formation.
- Targeting NOX-mediated ROS offers a potential therapeutic strategy for thrombotic disorders.
Purpose of the Study:
- To investigate the efficacy of the pan-NOX inhibitor APX-115 in suppressing platelet activation and thrombus formation.
- To elucidate the molecular mechanisms by which APX-115 affects ROS production and platelet signaling pathways.
Main Methods:
- Assessed intracellular and extracellular ROS production in collagen-stimulated human platelets.
- Evaluated platelet aggregation, P-selectin exposure, ATP release, and integrin αIIbβ3 activation.
- Analyzed signaling pathways including tyrosine kinases, PKC, calcium mobilization, MAPK, and thromboxane production.
- Studied thrombus formation under shear and arterial thrombosis in murine models.
Main Results:
- APX-115 significantly inhibited ROS production, platelet aggregation, P-selectin exposure, and ATP release.
- APX-115 preserved protein tyrosine phosphatase activity, reducing downstream signaling and calcium mobilization.
- APX-115 suppressed integrin activation, thromboxane production, and phosphatidylserine exposure, reducing thrombus formation without increasing bleeding time.
Conclusions:
- APX-115 effectively inhibits NOX-mediated ROS production, platelet activation, and thrombus formation.
- APX-115 demonstrates potential as a novel antiplatelet and antithrombotic agent for cardiovascular disorders.
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