Antimicrobial lipids: Emerging effector molecules of innate host defense

Figure 1 Simplified lipid biosynthesis pathway highlighting the lipids and the enzymes with a putative role in innate immunity. Lipid classes with documented antibacterial activity are in bold, key enzymes that may be induced in response to infection and inflammation (homo sapiens nomenclature) are in red. MUFA: Monounsaturated fatty acids; PUFA: Polyunsaturated fatty acids; ACC1: Acetyl-CoA carboxylase 1; FASN: Fatty acid synthase; SCD: Stearoyl-CoA desaturase-1; ACSL1: Acyl-CoA synthetase long-chain family member 1; FADS2: Fatty acid desaturase 2; SOAT1: Sterol O-acyltransferase 1 (SOAT1, also known as acyl-Coenzyme A: Cholesterol acyltransferase 1 or ACAT 1); HMG-CoA: 3-hydroxy-3-methylglutaryl-CoA.

Figure 2 Working model of epithelial cell mediated innate defense. In response to microbial products and cytokines epithelial cells increase the production and secretion of antimicrobial lipids and antimicrobial proteins as well as cytokines and chemokine to eradicate infection in concert with other defense components of the body. PRR: Pattern recognition receptor for microbial products; AML: Antimicrobial lipids; AMP: Antimicrobial proteins. Other sources: Other defense cells recruited to the site of infections such as macrophages and neutrophils.