Metabolism of tissue macrophages in homeostasis and pathology

Cellular metabolism orchestrates the intricate use of tissue fuels for catabolism and anabolism to generate cellular energy and structural components. The emerging field of immunometabolism highlights the importance of cellular metabolism for the maintenance and activities of immune cells. Macrophages are embryo- or adult bone marrow-derived leukocytes that are key for healthy tissue homeostasis but can also contribute to pathologies such as metabolic syndrome, atherosclerosis, fibrosis or cancer. Macrophage metabolism has largely been studied in vitro. However, different organs contain diverse macrophage populations that specialize in distinct and often tissue-specific functions. This context specificity creates diverging metabolic challenges for tissue macrophage populations to fulfill their homeostatic roles in their particular microenvironment and conditions their response in pathological conditions. Here, we outline current knowledge on the metabolic requirements and adaptations of macrophages located in tissues during homeostasis and selected diseases.

Quantitative Proteomics of Polarised Macrophages Derived from Induced Pluripotent Stem Cells

Macrophages (M_Φ) are highly heterogenous and versatile innate immune cells involved in homeostatic and immune responses. Activated M_Φ can exist in two extreme phenotypes: pro-inflammatory (M1) M_Φ and anti-inflammatory (M2) M_Φ. These phenotypes can be recapitulated in vitro by using ligands of toll-like receptors (TLRs) and cytokines such as IFNγ and IL-4. In recent years, human induced pluripotent stem cells (iPSC)-derived M_Φ have gained major attention, as they are functionally similar to human monocyte-derived M_Φ and are receptive to genome editing. In this study, we polarised iPSC-derived M_Φ to M1 or M2 and analysed their proteome and secretome profiles using quantitative proteomics. These comprehensive proteomic data sets provide new insights into functions of polarised M_Φ.