Antimicrobial lipids: Emerging effector molecules of innate host defense

Table 1 Genes involved in lipid metabolism and transport regulated by innate immune pathways

Role	Gene name	Encoded protein	Function of the encoded protein	Cellular source	Regulators
Biosynthesis	acc1	Acetyl-CoA carboxylase 1	Catalyzes the rate limiting irreversible carboxylation of acetyl-CoA to produce malonyl-CoA	Hepatic tissue1	LPS via sterol regulatory element-binding protein-1c
	acsl1	Long-chain fatty-acid-coenzyme A ligase	Converts free long-chain fatty acids into fatty acyl-CoA esters	Mp, DC, EN, Mo	LPS, IFN-γ, TNF-α, IL22, Mtb-derived lipopeptide
	elov	Elongation of long chain fatty acids	Possibly implicated in tissue-specific synthesis of very long chain fatty acids and sphingolipids3	Mp, DC, CD34+, TE,B, F, EN	LPS, Zy, Schi, IL1, IFN-β, IFN-γ, IL10, TGF-β
	fad	Fatty acid desaturase	Catalyzes biosynthesis of highly unsaturated fatty acids. FADS2 catalyzes production of the mono-unsaturated fatty acid sapienate, the most abundant fatty acid in sebum	Mp,DC, CD34+, TE, B, EN	LPS, Zy, Schi, IL1, IFN-γ, IL10, TGF-β
	fasn	Fatty acid synthase	Catalyzes the formation of long-chain fatty acids from acetyl-CoA, malonyl-CoA and NADPH	Mp, DC, CD34+, TE, F, EN	LPS, Zy, Schi, IL1, IFN-γ, TGF-β
	lcat	Lecithin cholesterol acyltransferase2	Esterifies free cholesterol transported in plasma lipoproteins. Activated by apolipoprotein A-I	Mp, DC, CD8+ DC, B, F	LPS, Schi, IFN-β, IFN-γ, Yersinia + IFN-γ, Vit D3 + IFN-γ, IL10
	lipA	Lipase A3	Intracellular hydrolysis of internalized cholesteryl esters and triglycerides. Activation of endogenous cellular cholesteryl ester formation	Mo, Mp, DC, TE, EN, K, BrE, L, Mg	TLR agonists, IL1, Type I and II IFNs, γ, Diff/Polar
	scd4	Stearoyl-CoA desaturase	Catalyzes the desaturation of very long chain acyl-CoAs	Mo, Mp, L, CD8+ DC, TE, F, EN, K, BrE, Mg	LPS, Zy, TLR agonist, IL1, Type I and II IFNs, Yersinia + IFN-γ, Vit D3 + IFN-γ, Diff/Polar
	soat15	Sterol o-acyltransferase3	Catalyzes the formation of fatty acid-cholesterol esters	Mo, Mp, DC, TE, EN, L, Mg	TLR agonists, Type I and II IFNs, IL1, Diff/Polar
Transport	cetp	Cholesteryl ester transfer protein3	Involved in the transfer of insoluble cholesteryl esters in the reverse transport of cholesterol	Mo, Mp, DC, TE, EN, K, L, Mg	TLR agonists, IL1,Type I and II IFNs, Diff/Polar
	fabp	Fatty acid binding proteins	Intracellular lipid transport	Mp, DC, CD34+, TE, B, F, EN	LPS, Zy, Schi, IL1, Type I and II IFNs, IL10, TGF-β
	ffar	Free fatty acid receptor	Receptor for short chain fatty acids (FFAR2) and medium to long fatty acids (FFAR1). FFAR2 is expressed at relatively high levels in peripheral blood leukocytes	Mp, DC, CD34+,TE, EN	LPS, Zy, Schi, IL1, IFN-γ, TGF-β
	slc27A	Solute carrier family 27	Translocation of long-chain fatty acids across the plasma membrane. Some involved in bile acid synthesis	Mp, DC, CD34+, TE, B, F, EN	LPS, Zy, Schi, IL1, IFN-γ, IFN-β, IL10, TGF-β

¹Chen et al, J Pineal Res 2011 Nov; 51: 416-25 DOI: 10.1111/j.1600-079X.2011.00905.x;

²Profiles for mouse only;

³Profiles for human only;

⁴scd1 in mice;

⁵Also known as acat1 (acyl-Coenzyme A: Cholesterol acyltransferase 1). Data were extracted from NCBI Gene Expression Omnibus (GEO Profiles) and Swiss-Prot (http://www.uniprot.org/). Unless specified otherwise entries were for both mouse and human species. Mo: Monocytes; Mp: Macrophages; DC: Dendritic cells; TE: Thyroid epithelial cells; EN: Endothelial cells; L: Lung epithelial cells; Mg: Microglia; F: Fibroblasts; K: Keratinocytes; BrE: Bronchial epithelial cells; B: B-cells; Dex: Dexamethasone; Diff/Polar: Differentiation and polarization; IFN: Interferon; IL: Interleukin; LPS: Lipopolysaccharide; TGF-β: Transforming growth factor β; TNF-α: Tumor necrosis factor α; VitD3: Vitamin D3; Zy: Zymogen; Schi: Schistosoma antigen; Mtb: Mycobacterium tuberculosis.