Complete exchange of viral cholesterol

Area of Science:

• Biochemistry
• Virology
• Membrane Biology

Background:

• Enveloped viruses like Sindbis virus and vesicular stomatitis virus contain cholesterol in their membranes.
• The role and dynamics of viral cholesterol in relation to external lipid environments are not fully understood.

Purpose of the Study:

• To quantify the exchange of cholesterol between enveloped viruses and external lipid sources.
• To investigate the rate and extent of viral cholesterol transfer.

Main Methods:

• Utilized biosynthetically labeled cholesterol to track its movement.
• Incubated enveloped viruses with lipid vesicles and serum at 37°C.
• Measured cholesterol transfer using varying lipid vesicle compositions.

Main Results:

• Viral cholesterol spontaneously and completely transferred to both lipid vesicles and serum.
• Approximately 50% of viral cholesterol transferred in 4 hours, and over 90% in 24 hours.
• Cholesterol transfer occurred similarly regardless of vesicle cholesterol content, and even occurred from vesicles to viruses.

Conclusions:

• Enveloped viruses actively exchange cholesterol with their surroundings.
• Viral membrane cholesterol is in dynamic equilibrium with cholesterol in serum and potentially cellular cholesterol.