Abstract
INTRODUCTION: Cardiovascular disease (CVD) is the leading cause of death worldwide and is substantially caused by high cholesterol levels. High levels of low-density lipoprotein cholesterol (LDL-C) lead to atherosclerosis, which greatly raises the risk of heart disease, such as heart attack, stroke, and so on. Therapeutic strategies for lowering cholesterol levels include the use of statins and PCSK9 inhibitors. To further reduce intestinal cholesterol absorption, the combination of ezetimibe with statin is an effective approach for controlling LDL-C levels and reducing cardiovascular disease risk. The Niemann-Pick C1-Like 1 (NPC1L1) protein is an important regulator of cholesterol absorption in the intestines and is a clinically proven target for lowering LDL-C levels. Although ezetimibe is prescribed for hypercholesterolemia, which blocks NPC1L1-mediated cholesterol absorption, its prolonged use could lead to hepatotoxicity, prompting the search for safer alternatives. OBJECTIVE: To explore the interaction of ergosterol with NPC1L1 and assess its potential to modulate cholesterol absorption using in silico methods. METHODS: Molecular docking, ADMET profiling, molecular dynamics (MD) simulations, post-MD analysis, and MM-PBSA binding free energy calculations were conducted to study ergosterol-NPC1L1 interactions and compare them with NPC1L1-ezetimibe and NPC1L1-cholesterol complex. RESULTS: Docking and ADMET analyses revealed the existence of robust hydrophobic interaction of ergosterol with the binding pocket of NPC1L1 (binding energy -11.941 kcal/mol), identical to the binding of ezetimibe (-12.38 kcal/mol) and cholesterol (-11.432 kcal/mol), exhibiting comparable binding energies along with favourable pharmacokinetic properties. Molecular dynamics (MD) simulations and post-MD trajectory analyses suggest that the NPC1L1-ergosterol complex maintains structural stability during the simulation period. MM-PBSA binding free energy calculations consistently suggested a strong and stable interaction between NPC1L1-ergosterol (-27.61 ± 3.72 kcal/mol), comparable to that of NPC1L1-ezetimibe (-19.42 ± 4.87 kcal/mol) and NPC1L1-cholesterol (-32.53 ± 3.71 kcal/mol) complex. CONCLUSION: Our computational modelling studies suggested that ergosterol forms energetically favourable interactions with NPC1L1, hinting at its potential as a candidate for hypercholesterolemia and CVD management. However, comprehensive preclinical and clinical investigations are required to substantiate its therapeutic relevance.