P66Shc mediates increased platelet activation and aggregation in hypercholesterolemia

Area of Science:

• Cardiovascular Biology
• Hematology
• Oxidative Stress Research

Background:

• Hypercholesterolemia induces a prothrombotic state, characterized by platelet hyperactivity.
• Oxidative stress is a key contributor to platelet hyperactivation in hypercholesterolemia.
• The role of p66Shc, a known determinant of oxidative stress, in platelet function remains unclear.

Purpose of the Study:

• To investigate the role of p66Shc in mediating platelet hyperactivation and hyperaggregation in hypercholesterolemia.
• To determine if p66Shc expression is altered in platelets during hypercholesterolemia.

Main Methods:

• Assessed p66Shc expression in human and mouse platelets using qRT-PCR and immunoblotting.
• Induced hypercholesterolemia in wild-type and p66Shc-deficient (p66ShcRNAi) mice via high-fat diet.
• Evaluated platelet activation (P-selectin expression), aggregation, and reactive oxygen species production.

Main Results:

• p66Shc is expressed in human and mouse platelets and its expression is upregulated by hypercholesterolemia.
• Hypercholesterolemia amplified thrombin-induced platelet activation and aggregation in wild-type mice.
• These exaggerated platelet responses and reactive oxygen species production were significantly reduced in p66ShcRNAi mice.

Conclusions:

• Hypercholesterolemia upregulates p66Shc expression in platelets.
• p66Shc mediates platelet oxidative stress, hyperreactivity, and hyperaggregation in the context of hypercholesterolemia.