Lipids: a key player in the battle between the host and microorganisms

Abstract

Journal of Lipid Research Volume 53, 2012 2487 Products of gram negative bacteria (LPS), gram positive bacteria (lipoteichoic acid), fungi (zymosan), and viruses (RNA) are recognized by toll receptors on macrophages and other cells and thereby induce marked changes in lipid and lipoprotein metabolism ( 1 ). It is now increasingly recognized that lipids and lipoproteins play an important role in host defense as part of the innate immune system [for detailed review, see ( 1 )]. For example, lipoproteins including HDL, chylomicrons, VLDL, and LDL can bind and neutralize LPS, lipoteichoic acid, and viruses. The binding of LPS by lipoproteins has been shown to protect animals from LPS induced death. Numerous studies have shown that animals that have elevations in serum lipid/lipoprotein levels are protected from the toxicity of LPS, whereas animals with low circulating lipid/ lipoprotein levels are more sensitive to the toxic effects of LPS. Studies have shown that HDL may inhibit the ability of certain viruses to penetrate cells. Moreover, lipoproteins can block the adhesion of bacteria to host cells and reduce tissue invasion ( 2 ). Another example involves cellto-cell communication between bacteria, which coordinates gene expression and the production of virulence factors ( 3 ). Studies have shown that Staphylococcus aureus produce an autoinducing peptide that binds to surface receptors