Cyclandelate. An inhibitor of cholesterol esterification

Area of Science:

• Biochemistry
• Cell Biology
• Pharmacology

Background:

• Cholesterol metabolism is crucial for cellular function and homeostasis.
• Dysregulation of cholesterol metabolism is implicated in various diseases.
• Cyclandelate is a vasodilator with potential effects on cellular processes.

Purpose of the Study:

• To investigate the in vitro effects of cyclandelate on cholesterol metabolism in human cells.
• To elucidate the mechanism by which cyclandelate influences cholesterol pathways.

Main Methods:

• Human fibroblasts and monocyte-derived macrophages were used for in vitro studies.
• Acetate incorporation into sterols and fatty acids was measured.
• Low-density lipoprotein (LDL) uptake and hydrolysis were assessed.
• Cholesterol esterification was quantified.
• Acyl-CoA: cholesterol acyltransferase (ACAT) activity was measured in rat liver microsomes.

Main Results:

• Cyclandelate (100 mumol/L) inhibited acetate incorporation into sterols but not fatty acids in fibroblasts.
• Prolonged exposure to cyclandelate reduced LDL uptake and hydrolysis.
• Cholesterol esterification was inhibited by 90% in fibroblasts and macrophages.
• Cyclandelate directly inhibited rat liver microsomal ACAT activity by 74% at 100 mumol/L.
• The intact cyclandelate molecule was necessary for maximal ACAT inhibition.

Conclusions:

• Cyclandelate significantly interferes with key steps of cholesterol metabolism, including synthesis and esterification.
• The drug's action on cholesterol esterification is likely mediated by direct inhibition of ACAT.
• These findings suggest a potential role for cyclandelate in modulating cellular cholesterol homeostasis.