Amplification and labeling of the RNA samples were performed using the Illumina TotalPrep RNA Amplification (Applied Biosystems) with an input of 500 ng of total RNA per sample. lipolysis and FA -oxidation that paralleled a prolonged drop in adipose triglyceride lipase (ATGL). TLR agonist-induced TAG storage is a multifaceted process that persists long after most early pro-inflammatory responses have subsided and may contribute to the formation of lipid-laden macrophages in infected tissues. == Introduction == Lipid droplets Triclabendazole (LD,4also called lipid bodies) are cytosolic collections of neutral lipids (triglycerides and cholesteryl esters) that may be both storage depots and foci for the production of eicosanoids and other important mediator molecules (1). They may also give macrophages the foamy appearance that is often noted within granulomas, xanthogranulomatous lesions, and atherosclerotic vessels. Although triglycerides (TAG) may comprise a substantial fraction of the lipids in LD (2), the mechanisms that promote long term TAG storage within macrophages have received little study. Glucose is the major food of resting macrophages (3,4). It provides precursors for the synthesis of glycerolipids, Triclabendazole amino acids, and nucleic acids via pathways that also supply the cell with essential NADH, NADPH, and ATP. When macrophages sense bacterial LPS, they greatly increase their uptake and catabolism of glucose. Sensing LPS also increases fatty acid (FA) uptake (5,6). In a seeming paradox, a large fraction of the newly acquired FA is incorporated into TAG and stored in LD; FA -oxidation and the production of ATP via oxidative phosphorylation decrease. Intrigued by observing that LD persisted within LPS-exposed macrophages even as the ambient glucose supply was depleted, we used a load-chase model to study the mechanisms that promote long term TAG retention in stimulated primary macrophages. == EXPERIMENTAL PROCEDURES == == Triclabendazole == == == == Mice == C57BL/6 and B6.B10ScN-Tlr4lps-del/JthJv (TLR4-deficient) mice were purchased Triclabendazole from The Jackson Laboratory and used for experiments when they were 512 weeks of age.MyD88/mice were kindly provided by Alan Sher, NIAID, National Institutes of Health. All protocols were approved by the IACUC of the Division of Intramural Research, NIAID, National Institutes of Health. == Reagents == Fatty acids were obtained from NuChek, PAM3CysK4(PAM) from InvivoGen, and poly(I:C) from Sigma or InvivoGen. LPS was prepared in our laboratory fromEscherichia coliO14 orE. coliLCD25 (7). The TLR agonists were tested in preliminary studies to establish each compound’s ability to elicit IL-6 (MyD88-dependent) and/or RANTES (TRIF-dependent) production by macrophagesin vitroand to choose effective stimulatory concentrations of each. Poly(I:C) elicited RANTES but not IL-6; PAM only elicited IL-6, and LPS stimulated the production of both cytokines. Radioisotopes were obtained from PerkinElmer Life Sciences ([3H]palmitate; [U-14C]glucose) or Moravek ([1-14C]palmitate; [9,10-3H]oleate). == Macrophage Cultures == Thioglycollate-elicited peritoneal macrophages (TEPM), harvested 4 or 5 5 days after injecting 1.0 ml of 3% Brewer’s thioglycollate (BD Biosciences/BBL) intraperitoneally, were allowed to adhere to plastic wells for 46 h in complete RPMI 1640 medium (8). The cells (typically 5.5 105/0.5 ml PDGFRA of medium in 24-well Costar plates) were then washed twice with PBS and cultured further in DMEM (Sigma D5030) that contained 0.5% low endotoxin fetal bovine serum (Hyclone), 1 g/liter (5.5 mm) glucose, 44 mmNaHCO3, 1 mmsodium pyruvate, 2 mml-glutamine, 100 units/ml penicillin G, and 100 g/ml streptomycin (cDMEM). Cultures were carried in a humidified incubator at 37 C in an atmosphere of 5% CO2. Elutriated human monocytes were obtained from normal volunteers by the Clinical Center Blood Bank Elutriation Service, National Institutes Triclabendazole of Health, with Institutional Review Board approval and subject consent. Prior to.