Enhancement of ABCA1 and ABCG1 Expression and Cholesterol Efflux by a Metabolite of Tipelukast: A Potential Therapeutic Strategy for Atherosclerosis

Abstract

Aims: MN-001 (tipelukast), a compound with lipid-modulating and anti-inflammatory properties, and its active metabolite MN-002, have been suggested to influence cholesterol metabolism. This study aimed to investigate whether MN-001 and MN-002 enhance cholesterol efflux via ABCA1 and ABCG1, thereby reducing foam cell formation. We also evaluated cholesterol efflux capacity in patients with diabetes before and after MN-001 administration.

Methods: Cholesterol efflux was assessed in THP-1 macrophages treated with MN-001 and MN-002 in the presence of ApoA-I or HDL. ABCA1 and ABCG1 expression were evaluated using western blot and qPCR analyses. A 12-week observational study in patients with diabetes evaluated the cholesterol efflux capacity using ApoB-depleted serum and radiolabeled J774.1 macrophages. Molecular docking simulations were conducted to explore MN-002 binding affinities, aiming to identify potential target proteins and elucidate the molecular mechanisms underlying their effects on cholesterol metabolism.

Results: MN-002 enhanced ABCA1-mediated cholesterol efflux and upregulated ABCA1 expression independently of PKA. It also increased ABCG1 expression; however, neither MN-001 nor MN-002 influenced HDL-mediated efflux. MN-001 showed no significant improvement in cholesterol efflux capacity (p = 0.6507) in patients with diabetes. Molecular docking simulations indicated that MN-002 may bind to PPAR-alpha, suggesting a potential mechanism for its effects.

Conclusion: MN-002 offers a novel therapeutic approach for atherosclerosis by upregulating ABCA1 and ABCG1 expression and enhancing ApoA-I-mediated cholesterol efflux. Further studies are required to clarify the underlying mechanisms and assess their clinical potential in atherosclerosis and metabolic disorders.