Fig. 1
From: Functional polarization of tumor-associated macrophages dictated by metabolic reprogramming
Distinct metabolic patterns of M1 and M2 macrophages. In M1 macrophages high gycolytic flux and the shunting of intermediates to PPP favor ROS production. The TCA cycle is truncated due to the expression of IRG1 and the impaired IDH activity. Itaconate production inhibits SDH and succinate accumulation further stabilizes HIF-1α to strengthen glycolysis. M2 macrophages reply on β-oxidation of fatty acids and glutaminolysis to drive TCA cycle. The production of polyamines and proline from L-arginine facilitate tumorigenesis. Abbreviations: α-KG, α-ketoglutarate; ARG1, arginase 1; FAO, fatty acid oxidation; GLS, glutaminase; HIF-1α, hypoxia inducible factor-1α; IDH, isocitrate dehydrogenase; iNOS, inducible nitric oxide synthase; IRG1, aconitate decarboxylase 1; NO, nitric oxide; NOXs, NADPH oxidases; PPP, pentose phosphate pathway; ROS, reactive oxygen species; SDH, succinate dehydrogenase; TCA, tricarboxylic acid (Created with BioRender.com)