fig2

Figure 2. M2 macrophage metabolism. M2 macrophages rely on fatty acid oxidation (or β-oxidation) and L-glutamine metabolism to fuel the TCA cycle, which provide ATP for the cells. The pentose phosphate pathway (PPP) of M2 macrophages is decreased. Arginase 1 (ARG1) is highly expressed in M2 macrophages and competes with iNOS for their substrate L-arginine, thereby reducing NO production and leading to the production of urea and L-ornithine. α-KG: α-ketoglutarate; ATP: adenosine triphosphate; CARKL: carbohydrate kinase-like protein; CPT: carnitine palmitoyl transferase; LAL: lysosomal acid lipase; ROS: reactive oxygen species; SLC3a2: solute carrier family 3 member 2; TCA: tri-carboxylic acid; UDP-GlcNAc: uridine diphosphate N-acetylglucosamine.