Binary phase behavior of angiotoxic oxidized cholesterols with cholesterol

Area of Science:

• Biochemistry
• Molecular Biology
• Physical Chemistry

Background:

• Oxidized cholesterols are cytotoxic and implicated in cell membrane disruption.
• Understanding their physical mechanisms is crucial for cell biology and disease research.

Purpose of the Study:

• To investigate the physical mechanisms by which oxidized cholesterols disrupt cell membranes.
• To construct binary phase diagrams of oxidized cholesterols with cholesterol.

Main Methods:

• Construction of binary phase diagrams for cholesterol with 25-hydroxycholesterol, 7-ketocholesterol, and cholestane 3 beta, 5 alpha,6 beta-triol.
• Assessment of solubility of these compounds in phospholipid bilayers.

Main Results:

• 25-hydroxycholesterol and 7-ketocholesterol exhibit continuous solubility with cholesterol in solids, with liquid phase clustering.
• These two compounds show significantly different solubilities in phospholipid bilayers.
• Cholestane 3 beta, 5 alpha,6 beta-triol forms a eutectic with cholesterol and is soluble in phospholipid bilayers.

Conclusions:

• The three oxidized cholesterols likely employ distinct mechanisms for cell membrane disruption.
• Solubilization by specific membrane components dictates the mechanism of action for each oxidized cholesterol.