Lecithin-cholesterol acyltransferase in brain: Does oxidative stress influence the 24-hydroxycholesterol esterification?

What is it about?

24-Hydroxycholesterol (24OH-C, also called cerebrosterol) is esterified by the enzyme LCAT in the cerebrospinal fluid (CSF). We report here that the level of 24OH-C esters was significantly lower in CSF of patients with amyotrophic lateral sclerosis than in healthy subjects. Similarly, the level of 24OH-C esters in plasma was significantly lower in patients than in controls. The enzyme amount in CSF, as measured by densitometry of the protein band revealed by immunoblotting, was about 4-fold higher in patients than in controls. Oxidative stress reduced LCAT activity in vitro. 24OH-C effectively stimulated the enzyme secretion from astrocytoma cells in culture.

Featured Image

Why is it important?

The results indicate that reduced levels of 24OH-C esters reflect impaired activity of LCAT in the brain of patients suffering from amyotrophic lateral sclerosis, although astrocytes might be stimulated by accumulation of unesterified 24OH-C to increase their secretion of the ezyme. Moreover, as the value of 24OH-C esters in CSF correlates with that in plasma, the measurement of the level of 24OH-C esters fraction in plasma is an important tool to evaluate the degree of oxidative stress in the brain.

Perspectives