Regulatory crosstalk between KLF5, miR-29a and Fbw7/CDC4 cooperatively promotes atherosclerotic development

Area of Science:

• Cardiovascular Biology
• Molecular Medicine
• Inflammation Research

Background:

• Atherogenesis is a complex inflammatory process involving endothelial dysfunction, lipid accumulation, and vascular smooth-muscle cell (VSMC) proliferation.
• The precise molecular mechanisms driving atherogenesis remain incompletely understood, necessitating further investigation into key regulatory pathways.

Purpose of the Study:

• To elucidate the molecular mechanism by which oxidized low-density lipoprotein (oxLDL) promotes VSMC proliferation and contributes to atherogenesis.
• To investigate the role of Krüppel-like factor 5 (KLF5), miR-29a, and Fbw7/CDC4 in a potential positive feedback loop within HASMCs.

Main Methods:

• Investigated the effect of oxLDL on KLF5 and miR-29a expression in human aortic smooth muscle cells (HASMCs).
• Utilized luciferase reporter assays to confirm miR-29a targeting of Fbw7/CDC4 3'UTR.
• Assessed the impact of miR-29a on KLF5 stability by examining ubiquitination levels.

Main Results:

• Oxidized LDL (oxLDL) induced Krüppel-like factor 5 (KLF5) expression, which subsequently increased miR-29a levels in HASMCs.
• Increased miR-29a downregulated Fbw7/CDC4 by targeting its 3' untranslated region (3'UTR).
• This led to reduced Fbw7/CDC4-dependent ubiquitination of KLF5, enhancing KLF5 stability and promoting a positive feedback loop that stimulates VSMC proliferation and atherogenesis.

Conclusions:

• The study reveals a novel oxLDL-activated positive feedback loop involving KLF5, miR-29a, and Fbw7/CDC4 that drives VSMC proliferation and promotes atherosclerotic development.
• This regulatory crosstalk highlights a critical mechanism in atherogenesis.
• Targeting miR-29a emerges as a potential therapeutic strategy to mitigate atherosclerosis progression.