Secretion of lecithin : cholesterol acyltransferase by brain neuroglial cell lines

The ability of different human and rat brain cell lines (neuronal and gliom al) to secrete lecithin:cholesterol acyltransferase (LCAT) was examined. Of these, the strongly secreting human gliomal (U343 and U251) cell lines wer e selected for a detailed study of enzymatic and structural properties of t he secreted LCAT. Both plasma- and brain-derived enzymes are inhibited by D TNB (90%) and are activated by apolipoprotein A-I. LCAT mRNA was measured i n these cell lines at levels similar to that found in HepG2 cells. In contr ast, apoA-I, apoE, and apoD mRNAs were undetectable in these cell lines. Th e presence of functional LCAT secreted by cultured nerve cells provides an in vitro model to study the expression and function of LCAT in the absence of others factors of plasma cholesterol metabolism. (C) 1999 Academic Press .