Parkin Modulates ERRα/eNOS Signaling Pathway in Endothelial Cells

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Parkin is known for its role in mitophagy.
• Emerging evidence suggests parkin has functions beyond mitophagy.
• The study investigates parkin's role in endothelial cells (ECs).

Purpose of the Study:

• To investigate the role of parkin in regulating the ERRα/eNOS pathway in endothelial cells.
• To elucidate the mechanism by which parkin affects eNOS levels.

Main Methods:

• Utilized mouse aortic endothelial cells (MAECs) and HL-1 cells, transfected with parkin plasmid or siRNA.
• Employed ERRα inhibitor, autophagy inhibitors (3-MA, Bafilomycin A1), and caspase inhibitor (Z-VAD-FMK).
• Assessed protein levels via Western blotting, apoptosis and ROS via flow cytometry, mitochondrial potential using JC-1 and TMRM, and ERRα ubiquitination via immunoprecipitation.

Main Results:

• Parkin overexpression reduced total-eNOS and p-eNOS, correlating with ERRα downregulation and enhanced ERRα ubiquitination.
• ERRα inhibition decreased eNOS levels, while ERRα overexpression increased them.
• Parkin overexpression induced mitochondrial dysfunction and apoptosis, independent of autophagy and apoptosis pathways.

Conclusions:

• Parkin overexpression downregulates eNOS in endothelial cells.
• This downregulation is likely mediated by the ubiquitination of ERRα.
• The findings highlight a novel role for parkin in regulating the ERRα/eNOS pathway.