Zinc regulates reactive oxygen species generation in platelets

Area of Science:

• Biochemistry
• Hematology
• Cell Biology

Background:

• Vascular complications from atherosclerosis are a leading cause of death.
• Platelet activation involves reactive oxygen species (ROS) and zinc (Zn²⁺).
• The role of Zn²⁺ in platelet ROS production is not well understood.

Purpose of the Study:

• To investigate the relationship between cytosolic zinc levels ([Zn²⁺]_i) and ROS production in platelets.
• To explore the signaling pathways involved in Zn²⁺-mediated ROS generation.

Main Methods:

• Platelet treatment with Zn²⁺ chelator (TPEN) and ionophores.
• Measurement of ROS production, glutathione (GSH) levels, and glutathione peroxidase (GPx) activity.
• Inhibition of NADPH oxidase and mitochondria, and assessment of Erk1/2 and JNK phosphorylation.

Main Results:

• Chelation of Zn²⁺ abrogated agonist-evoked ROS production, GSH levels, and GPx activity.
• Increased [Zn²⁺]_i potentiated ROS generation and decreased GSH levels and GPx activity.
• Zn²⁺-dependent ROS production involved NADPH oxidase and mitochondria, and increased Erk1/2 and JNK phosphorylation.

Conclusions:

• Cytosolic zinc ([Zn²⁺]_i) is functionally associated with ROS production in platelets.
• This association may influence thrombus formation and have clinical implications in atherosclerosis.
• Zn²⁺ acts as a regulator of platelet ROS generation via signaling pathways.