Oleanolic acid ameliorates high glucose-induced endothelial dysfunction via PPARδ activation

Area of Science:

• Pharmacology
• Endothelial Biology
• Molecular Medicine

Background:

• Oleanolic acid (OA) is a natural triterpene with known hepatoprotective and anti-tumor effects.
• High glucose levels induce endothelial dysfunction, a key factor in cardiovascular diseases.
• Understanding the molecular mechanisms underlying OA's protective effects is crucial for therapeutic development.

Purpose of the Study:

• To investigate the effect of Oleanolic acid (OA) on high glucose-induced endothelial dysfunction.
• To elucidate the role of peroxisome proliferators-activated receptor delta (PPARδ) in OA's protective mechanism.
• To examine the involvement of the Akt/eNOS/NO pathway in OA-mediated endothelial protection.

Main Methods:

• Western blotting was used to assess nitric oxide (NO) production and Akt/eNOS phosphorylation.
• Luciferase reporter assays and qRT-PCR were employed to evaluate PPARδ activity and target gene expression.
• The Multi Myograph System was utilized to assess OA's effect on high glucose-impaired vasodilation in aortic rings.

Main Results:

• OA attenuated high glucose-induced reduction in NO production and Akt/eNOS phosphorylation in human umbilical vein endothelial cells (HUVECs).
• OA activated PPARδ activity, leading to increased expression of PPARδ target genes (PDK4, ADRP, ANGPTL4).
• Inhibition of PPARδ abolished OA's protective effects on NO production, Akt/eNOS phosphorylation, and vasodilation.

Conclusions:

• Oleanolic acid (OA) ameliorates high glucose-induced endothelial dysfunction.
• The protective effects of OA are mediated through the activation of PPARδ.
• OA improves endothelial function via the PPARδ-Akt/eNOS/NO signaling pathway, highlighting its therapeutic potential.