Fatty Acyl Esters of Hydroxy Fatty Acid (FAHFA) Lipid Families.

Paul L Wood

doi:10.3390/metabo10120512

Abstract

Fatty Acyl esters of Hydroxy Fatty Acids (FAHFA) encompass three different lipid families which have incorrectly been classified as wax esters. These families include (i) Branched-chain FAHFAs, involved in the regulation of glucose metabolism and inflammation, with acylation of an internal branched-chain hydroxy-palmitic or -stearic acid; (ii) ω-FAHFAs, which function as biosurfactants in a number of biofluids, are formed via acylation of the ω-hydroxyl group of very-long-chain fatty acids (these lipids have also been designated as o-acyl hydroxy fatty acids; OAHFA); and (iii) Ornithine-FAHFAs are bacterial lipids formed by the acylation of short-chain 3-hydroxy fatty acids and the addition of ornithine to the free carboxy group of the hydroxy fatty acid. The differences in biosynthetic pathways and cellular functions of these lipid families will be reviewed and compared to wax esters, which are formed by the acylation of a fatty alcohol, not a hydroxy fatty acid. In summary, FAHFA lipid families are both unique and complex in their biosynthesis and their biological actions. We have only evaluated the tip of the iceberg and much more exciting research is required to understand these lipids in health and disease.

Highlights

In this review, we we present anan abbreviated ofthree threemajor majorAcyl esters of Hydroxy present abbreviated overview overview of FattyFatty lipid families which individually serve unique metabolic and/or structuralAcids (FAHFA) lipid families which individually serve unique metabolic and/or structural functions (Figure 1)
We have only evaluated the tip of the iceberg and much required to understand these lipids in health and disease
O-acyl hydroxy fatty acids (OAHFA), are biosurfactants in the tear film of the eye, amniotic fluid, Ornithine-FAHFA are bacterial lipids synthesized by the acylation of short-chain 3-hydroxy semen, sperm, skin, and the vernix caseosa

Summary

Introduction

Acids (FAHFA) lipid families which individually serve unique metabolic and/or structural functions The ω-FAHFAs, represented in (B), are unique in that the hydroxy fatty acids are long-chain fatty acids with a terminal (ω) hydroxyl group. Ω-FAHFAs are unique in that they are synthesized by the acylation of very-long-chain ωhydroxy fatty synthetic pathway requires complex metabolic machinery for the ω-FAHFAs are acids. This synthetic pathway requires complex metabolic machinery for the biosynthesis of been termed o-acyl hydroxy fatty acids (OAHFA), are biosurfactants in the tear film of the eye, very-long-chain ω-hydroxy fatty acids (30 to 34 carbons). O-acyl hydroxy fatty acids (OAHFA), are biosurfactants in the tear film of the eye, amniotic fluid, Ornithine-FAHFA are bacterial lipids synthesized by the acylation of short-chain 3-hydroxy semen, sperm, skin, and the vernix caseosa. Families acylated ornithines as a permeability barrier in the membranes of bacteria

Branched-Chain

Wax Esters

Findings

Conclusions