Platelet MEKK3 regulates arterial thrombosis and myocardial infarct expansion in mice

Area of Science:

• Platelet biology
• Signal transduction
• Cardiovascular research

Background:

• Mitogen-activated protein kinases (MAPKs) are vital for platelet activation.
• The precise regulatory mechanisms of MAPKs in platelets are not fully understood.

Purpose of the Study:

• To investigate the role of MEKK3, a MAP3K family member, in platelet function and MAPK activation.
• To explore MEKK3 as a potential therapeutic target for antithrombosis and myocardial infarction (MI).

Main Methods:

• Expression analysis of MEKK3 in human and mouse platelets using RT-PCR and Western blot.
• Generation of megakaryocyte/platelet-specific MEKK3-deletion (MEKK3Δ) mice.
• In vitro assessment of platelet aggregation and degranulation.
• In vivo studies including FeCl3-induced carotid artery injury and a mouse model of MI.

Main Results:

• MEKK3 is expressed in platelets.
• MEKK3 deficiency reduced agonist-induced platelet aggregation and degranulation.
• MEKK3 deficiency impaired integrin αIIbβ3-mediated inside-out signaling and ERK1/2/JNK2 activation.
• MEKK3Δ mice exhibited delayed thrombus formation, reduced microthrombi, smaller infarct size, and improved cardiac function post-MI.

Conclusions:

• MEKK3 is essential for MAPK activation in platelets.
• MEKK3 plays a significant role in platelet function, thrombosis, and MI progression.
• MEKK3 represents a promising therapeutic target for antithrombotic strategies and limiting MI damage.