PPAR-γ promotes p38 MAP kinase-mediated endothelial cell permeability through activating Sirt3

Area of Science:

• Endothelial cell biology
• Vascular dysfunction mechanisms
• Neurological disease research

Background:

• Ischemia-reperfusion (I/R) injury causes vascular dysfunction, a key factor in acute ischemic stroke.
• Sirtuin 3 (Sirt3), a member of the sirtuin family, is implicated in neurological disease development.

Purpose of the Study:

• To investigate the role of Sirt3 in ischemia-reperfusion (I/R)-induced vascular dysfunction in human brain microvascular endothelial cells (HBMEC).
• To explore the relationship between Sirt3, p38 activation, and endothelial cell function.
• To elucidate the involvement of Peroxisome proliferator-activated receptor gamma (PPAR-γ) in Sirt3-mediated endothelial cell responses.

Main Methods:

• Overexpression of Sirt3 in an I/R injury model using HBMEC cells.
• Utilizing p38 activator (U-46619) to assess its interaction with Sirt3.
• Quantifying endothelial junction proteins (occludin, ZO-1, claudin-4) via qRT-PCR and Western blot.
• Employing PPAR-γ agonists and inhibitors to study PPAR-γ's role.

Main Results:

• Sirt3 overexpression reduced cell permeability and enhanced endothelial cell growth in the I/R model.
• p38 activation counteracted the beneficial effects of Sirt3.
• A positive correlation was observed between Sirt3 levels and inter-endothelial junction proteins.
• PPAR-γ was identified as a regulator targeting Sirt3 in the studied cells.

Conclusions:

• PPAR-γ activation of Sirt3 promotes endothelial cell growth, suggesting a therapeutic strategy for ischemic stroke.
• This research highlights the potential of targeting the PPAR-γ/Sirt3 pathway for treating ischemic stroke.