NF-κB-Regulated miR-99a Modulates Endothelial Cell Inflammation

Area of Science:

• Molecular Biology
• Immunology
• Cardiovascular Research

Background:

• Endothelial inflammation is a key factor in cardiovascular diseases like atherosclerosis.
• Lipopolysaccharide (LPS) is a potent inducer of endothelial inflammation.
• MicroRNAs (miRNAs) play critical roles in regulating cellular processes, including inflammation.

Purpose of the Study:

• To investigate the role of miR-99a in LPS-induced endothelial inflammation.
• To elucidate the underlying mechanisms involving the mTOR/NF-κB signaling pathway.
• To determine how NF-κB regulates miR-99a production.

Main Methods:

• Enzyme-linked immunosorbent assay (ELISA) to measure inflammatory factors.
• Overexpression of miR-99a in HUVECs.
• Bioinformatic analysis (PROMO) to predict transcription factor binding sites.
• Dual luciferase reporter assays, EMSA, and ChIP assays to confirm NF-κB binding and transcriptional activity.

Main Results:

• LPS treatment increased inflammatory factors (TNF-α, IL-6, IL-1β, MCP-1), inhibited miR-99a, and activated mTOR and NF-κB.
• miR-99a overexpression reversed LPS-induced inflammation, mTOR activation, and NF-κB translocation.
• NF-κB directly binds to the miR-99a promoter, promoting its transcription.

Conclusions:

• MiR-99a exerts anti-inflammatory effects in LPS-stimulated HUVECs by inhibiting the mTOR/NF-κB pathway.
• NF-κB positively regulates miR-99a transcription via binding to its promoter.
• These findings suggest a novel regulatory axis with potential therapeutic implications for atherosclerosis.