Biosynthesis of leukotriene B4 in human polymorphonuclear leukocytes: regulation by cholesterol and other lipids.

Leukotriene B4 (LTB4) is one of the most potent chemotactic compounds produced in macrophages and neutrophils. LTB4 is a product of arachidonic acid oxygenation by 5-lipoxygenase pathway. We present here the data on regulation of LT synthesis in human polymorphonuclear leukocytes by cholesterol, cholesterol sulfate and cholesterol phosphate. The addition of Pseudomonas aeruginosa lipopolysaccharides (LPS) with lipid vesicles containing phosphatidylcholine or phosphatidylcholine/cholesterol (70:30) showed that omitting cholesterol abolished the effect of LPS on LT synthesis. We show here the capacity of cholesterol sulfate, the most abundant sulfated sterol in human blood, to suppress LT production in human neutrophils and to neutralize the effect of P. aeruginosa LPS on LT synthesis. We suggest that sulfated lipids serve as specific endogenous regulators of LT synthesis in neutrophils, and anti-inflammatory therapy may be based on modification of cholesterol level and its conversion to anionic derivatives.