"Role of Cholesterol in Axon-Myelin Interactions: Insights from a Cell Membrane Model System"
Interaction between cells is essential in life and controls several biological processes, including communication between a fatty material called the myelin sheath and the axon in the central nervous system (CNS). Like an insulator around an electric wire, the myelin sheath wraps around the axon of the nerve cells in a process called myelination. It provides insulation, aiding the effective and efficient transfer of information via nerve impulses in the CNS. Improper myelination causes nerve impulse transfer to lag, resulting in memory loss and a decline in sensory ability, which may affect movement and speech, as seen in Alzheimer’s disease and Multiple sclerosis. Scientifically, a key factor in myelination is the interaction between a protein on the myelin sheath called myelin-associated glycoprotein (MAG) and a group of lipids called gangliosides (GT1b and GD1a) on the axon. The axon membrane is also very rich in cholesterol, which is known to cluster with gangliosides, forming a specialized region on the membrane called a lipid raft. Studies have shown that cholesterol and/or lipid rafts can alter protein interactions with gangliosides, but their effect on MAG interaction with GD1a and GT1b is uncertain. In my research, I utilized two different cell membrane model systems that mimic the axon and myelin membrane to investigate the effect of cholesterol and lipid rafts on the interaction between MAG and GD1a and GT1b. The results showed that cholesterol reduced this interaction. This finding will aid in the development of drugs for associated diseases.