Distinct phospholipid and sphingolipid species are linked to altered HDL function in apolipoprotein A-I deficiency

Abstract

Familial apolipoprotein A-I (apoA-I) deficiency (FAID) involving low levels of both apoA-I and high-density lipoprotein (HDL) cholesterol is associated with accelerated atherosclerosis. The objective of this study was to define distinctive patterns in the lipidome of HDL subpopulations in FAID in relationship to antiatherogenic activities. Five HDL subfractions were isolated by ultracentrifugation from plasma of FAID Caucasian patients (n=5) and age-matched healthy normolipidemic Caucasian controls (n=8), and the HDL lipidome (160 molecular species of 9 classes of phospholipids and sphingolipids) was quantitatively evaluated. Increased concentrations of numerous molecular species of lysophosphatidylcholine (up to 12-fold), ceramides (up to 3-fold), phosphatidylserine (up to 34-fold), phosphatidic acid (up to 71-fold), and phosphatidylglycerol (up to 20-fold) were detected throughout all five HDL subpopulations as compared with their counterparts from controls, whereas concentrations of phosphatidylethanolamine species were decreased (up to 5-fold). Moderately to highly abundant, within their lipid class, species of phosphatidylcholine, sphingomyelin, phosphatidylinositol, phosphatidylethanolamine, phosphatidylserine, and ceramide featuring multiple unsaturations were primarily affected by apoA-I deficiency; their HDL content, particularly that of phosphatidylcholine (34:2), was strongly correlated with HDL function, impaired in FAID. Metabolic pathway analysis revealed that sphingolipid, glycerophospholipid, and linoleic acid metabolism was significantly affected by FAID. These data reveal that altered content of specific phospholipid and sphingolipid species is linked to deficient antiatherogenic properties of HDL in FAID.