Colchicine enhances macrophage cholesterol efflux by targeting DTL-mediated ubiquitination and degradation of ABCA1

This study aims to elucidate the potential pharmacological mechanisms by which colchicine confers clinical benefits in patients with atherosclerotic cardiovascular disease, focusing on its effects on cholesterol efflux.

This study was conducted in multiple cellular models. First, cell viability was assessed and the optimal dosage of colchicine was screened via the Cell Counting Kit-8 assay. Subsequently, Oil Red O staining, commercial kit detection and Boron dipyrromethene (BODIPY) -cholesterol labelling were employed to analyse intracellular lipid accumulation, foam cell formation and cholesterol efflux rate in macrophages, respectively. Furthermore, molecular docking and transcriptome sequencing were performed to explore the potential therapeutic targets and underlying mechanisms of colchicine, followed by a series of cellular experiments (quantitative reverse transcription-PCR, ATP-binding cassette transporter A1 (ABCA1) degradation analysis, plasmid construction and transfection, co-immunoprecipitation, immunoblotting) for comprehensive validation of the identified potential mechanisms.

In the present study, we demonstrate that colchicine markedly promotes cholesterol efflux, a key process that reverses macrophage foam cell formation and consequently contributes to its cardioprotective effects. We identified modulation of the ubiquitination of ABCA1 as the pivotal mechanism by which colchicine enhances cholesterol efflux. Our findings reveal for the first time that denticleless E3 ubiquitin protein ligase homologue (DTL) functions as a crucial E3 ligase in this regulatory pathway. Mechanistically, colchicine suppresses DTL expression and disrupts its interaction with ABCA1, leading to increased ABCA1 protein stability, enhanced ABCA1-mediated cholesterol efflux and a subsequent reduction in foam cell formation.

Colchicine shows great promise for drug repurposing as a novel therapeutic agent. Its strong capacity to reverse foam cell formation highlights its potential to extend clinical use beyond gout management to cardiovascular secondary prevention.