How Mouse Macrophages Sense What Is Going On

Abstract

Macrophages are central to both innate and adaptive immunity. With few exceptions, macrophages are the first cells that sense trouble and respond to disturbances in almost all tissues and organs. They sense their environment, inhibit or kill pathogens, take up apoptotic and necrotic cells, heal tissue damage, and present antigens to T cells. Although the origins (yolk sac versus monocyte-derived) and phenotypes (functions, gene expression profiles, surface markers) of macrophages vary between tissues, they have many receptors in common that are specific to one or a few molecular species. Here, we review the expression and function of almost 200 key macrophage receptors that help the macrophages sense what is going on, including pathogen-derived molecules, the state of the surrounding tissue cells, apoptotic and necrotic cell death, antibodies and immune complexes, altered self molecules, extracellular matrix components, and cytokines, including chemokines.

Keywords: defense; immunity; inflammation; macrophages; pathogens.

Figure 1

Gene expression in resident tissue-specific macrophages (microglia, lung, liver, spleen, intestinal, adipose) and bone marrow-derived macrophages (BMDM) for comparison. Heat maps based on hierarchical clustering results from microarray and RNA-Seq data for (A) apoptosis receptors, (B) complement receptors, (C) toll-like receptors, (D) NOD-like receptors, (E) RNA and DNA sensors, (F) C-type lectins, (G) scavenger receptors, (H) integrins, (I) tumor necrosis factor receptor superfamily, (J) Fc receptors, (K) G-protein-coupled receptors, and (L) cytokine receptors. Gene expression levels are expressed in log₂ values, differences shown in color scale after Z-score transformation. Colors scale bar ranges from red (+3) to green (−3). Light gray indicates undetectable.

Figure 1

Gene expression in resident tissue-specific macrophages (microglia, lung, liver, spleen, intestinal, adipose) and bone marrow-derived macrophages (BMDM) for comparison. Heat maps based on hierarchical clustering results from microarray and RNA-Seq data for (A) apoptosis receptors, (B) complement receptors, (C) toll-like receptors, (D) NOD-like receptors, (E) RNA and DNA sensors, (F) C-type lectins, (G) scavenger receptors, (H) integrins, (I) tumor necrosis factor receptor superfamily, (J) Fc receptors, (K) G-protein-coupled receptors, and (L) cytokine receptors. Gene expression levels are expressed in log₂ values, differences shown in color scale after Z-score transformation. Colors scale bar ranges from red (+3) to green (−3). Light gray indicates undetectable.