Temporal Dynamics of CNS Cholesterol Esters Correlate with Demyelination and Remyelination

Elevated cholesterol ester levels have been observed in the CNS of patients with neurological diseases; yet, the source of cholesterol ester accumulation and whether it is directly linked to demyelination remain undefined. This study investigates the temporal dynamics of cholesterol esters using the Plp1-iCKO-Myrf mouse model, which features distinct phases of demyelination and remyelination. Our findings reveal that cholesterol ester levels increased with demyelination in both the brain and spinal cord. In the brain, cholesterol esters declined to normal levels during remyelination, whereas cholesterol esters remained elevated in the spinal cord, which had limited remyelination. Expression of acetyl-CoA-acyltransferase 1 (ACAT1) and lecithin-cholesterol acyltransferase (LCAT) were elevated during demyelination, implying the potential involvement of both proteins in the formation of cholesterol esters. Colocalization studies revealed that ACAT1 is predominantly expressed by microglia and LCAT is predominantly expressed by astrocytes during demyelination, highlighting the active roles of glial cells in cholesterol ester metabolism. In addition, we showed that administering the remyelinating drug, Sob-AM2, effectively reduced the level of cholesterol ester accumulation in the brain during demyelination, underscoring the potential that manipulating cholesterol ester regulatory pathways may offer for restoring cholesterol homeostasis and promoting remyelination in demyelinating diseases.