p66Shc Mediates SUMO2-induced Endothelial Dysfunction.

Area of Science:

• Biochemistry
• Molecular Biology
• Cardiovascular Research

Background:

• Sumoylation is a post-translational modification regulating physiological functions.
• Increased sumoylation, particularly SUMO2/3, negatively impacts vascular health.
• The precise molecular mechanisms behind SUMO2's detrimental vascular effects are not well understood.

Purpose of the Study:

• To investigate the role of p66Shc as a target of SUMO2.
• To elucidate the mechanism by which SUMO2 conjugation to p66Shc affects vascular endothelial function.
• To determine the in vivo relevance of SUMO2-p66Shc interaction in the context of hyperlipidemia-induced vascular dysfunction.

Main Methods:

• Utilized cell-based assays and mass spectrometry to identify p66Shc as a direct target of SUMO2.
• Generated p66ShcK81R knockin mice and crossed them with LDLr-/- mice to model hyperlipidemia.
• Performed mass spectrometry and Ingenuity Pathway Analysis to examine endothelial cell signaling changes.

Main Results:

• SUMO2 directly modifies p66Shc at lysine-81 (K81), a modification critical for its function.
• SUMO2ylation of p66Shc enhances its phosphorylation at serine-36 (S36), promoting mitochondrial translocation and oxidative function.
• p66ShcK81R knockin mice exhibited resistance to SUMO2-induced endothelial dysfunction and hyperlipidemia-related vascular damage.
• Ingenuity Pathway Analysis identified Rho-GTPase signaling as a key pathway affected by SUMO2-p66ShcK81.

Conclusions:

• SUMO2-p66Shc signaling is a key regulator of vascular endothelial function.
• p66ShcK81 sumoylation is an upstream event that modulates p66Shc signaling.
• This pathway mediates endothelial dysfunction and oxidative stress in hyperlipidemia.