Trajectory analysis quantifies transcriptional plasticity during macrophage polarization
Ontology highlight
ABSTRACT: Ctyokine-stimulated polarization and repolarization of murine bone marrow-derived macrophages (LPS + IFNγ, IL-4); bulk RNA-seq timecourse and bulk ATAC-seq for selected timepoints and conditions
Project description:In recent years, macrophages have been shown to be tremendously plastic in both in vitro and in vivo settings; however, it remains unclear whether macrophages retain any persistent memory of past polarization states which may then impact their future repolarization to new states. Here, we perform deep transcriptomic profiling at high temporal resolution as macrophages are polarized with cytokines that drive them into "M1" and "M2" molecular states. We find through trajectory analysis of their global transcriptomic profiles that macrophages which are first polarized to M1 or M2 and then subsequently repolarized demonstrate little to no memory of their polarization history. We observe complete repolarization both from M1 to M2 and vice versa, and we find that macrophage transcriptional phenotypes are defined by the current cell microenvironment, rather than an amalgamation of past and present states.
Project description:Macrophages polarize towards different subpopulations with distinct and partly antagonistic functions in various diseases. IFNγ/LPS-polarized M1-type macrophages can have antiangiogenic activity, whereas IL-4-induced M2-type macrophages can be proangiogenic and profibrotic. Therapeutic strategies to inhibit M2-type polarization while promoting M1-type polarization could serve to inhibit pathological angiogenesis and fibrosis. Here, by combining global quantitative time-course proteomics and phosphoproteomics with a small-molecule inhibitor screen we identify signaling events that promote specifically IL-4-induced and not IFNγ/LPS-induced macrophage polarization and found that the MEK inhibitor trametinib and the HDAC inhibitor panobinostat potently prevent M2-type macrophage polarization without inhibiting M1-type polarization. In contrast, selective B-Raf inhibition promotes M2-type polarization. Trametinib and panobinostat also blocked M2-type macrophage polarization and concomitantly angiogenesis and fibrosis in models of wound healing and neovascular age-related macular degeneration in vivo. Thus, these pharmacologic inhibitors could be utilized therapeutically to selectively block IL4-induced macrophage polarization and reduce pathologic angiogenesis and fibrosis.
Project description:Macrophages polarize towards different subpopulations with distinct and partly antagonistic functions in various diseases. IFNγ/LPS-polarized M1-type macrophages can have antiangiogenic activity, whereas IL-4-induced M2-type macrophages can be proangiogenic and profibrotic. Therapeutic strategies to inhibit M2-type polarization while promoting M1-type polarization could serve to inhibit pathological angiogenesis and fibrosis. Here, by combining global quantitative time-course proteomics and phosphoproteomics with a small-molecule inhibitor screen we identify signaling events that promote specifically IL-4-induced and not IFNγ/LPS-induced macrophage polarization and found that the MEK inhibitor trametinib and the HDAC inhibitor panobinostat potently prevent M2-type macrophage polarization without inhibiting M1-type polarization. In contrast, selective B-Raf inhibition promotes M2-type polarization. Trametinib and panobinostat also blocked M2-type macrophage polarization and concomitantly angiogenesis and fibrosis in models of wound healing and neovascular age-related macular degeneration in vivo. Thus, these pharmacologic inhibitors could be utilized therapeutically to selectively block IL4-induced macrophage polarization and reduce pathologic angiogenesis and fibrosis.
Project description:Macrophages polarize towards different subpopulations with distinct and partly antagonistic functions in various diseases. IFNγ/LPS-polarized M1-type macrophages can have antiangiogenic activity, whereas IL-4-induced M2-type macrophages can be proangiogenic and profibrotic. Therapeutic strategies to inhibit M2-type polarization while promoting M1-type polarization could serve to inhibit pathological angiogenesis and fibrosis. Here, by combining global quantitative time-course proteomics and phosphoproteomics with a small-molecule inhibitor screen we identify signaling events that promote specifically IL-4-induced and not IFNγ/LPS-induced macrophage polarization and found that the MEK inhibitor trametinib and the HDAC inhibitor panobinostat potently prevent M2-type macrophage polarization without inhibiting M1-type polarization. In contrast, selective B-Raf inhibition promotes M2-type polarization. Trametinib and panobinostat also blocked M2-type macrophage polarization and concomitantly angiogenesis and fibrosis in models of wound healing and neovascular age-related macular degeneration in vivo. Thus, these pharmacologic inhibitors could be utilized therapeutically to selectively block IL4-induced macrophage polarization and reduce pathologic angiogenesis and fibrosis.
Project description:Macrophages polarize towards different subpopulations with distinct and partly antagonistic functions in various diseases. IFNγ/LPS-polarized M1-type macrophages can have antiangiogenic activity, whereas IL-4-induced M2-type macrophages can be proangiogenic and profibrotic. Therapeutic strategies to inhibit M2-type polarization while promoting M1-type polarization could serve to inhibit pathological angiogenesis and fibrosis. Here, by combining global quantitative time-course proteomics and phosphoproteomics with a small-molecule inhibitor screen we identify signaling events that promote specifically IL-4-induced and not IFNγ/LPS-induced macrophage polarization and found that the MEK inhibitor trametinib and the HDAC inhibitor panobinostat potently prevent M2-type macrophage polarization without inhibiting M1-type polarization. In contrast, selective B-Raf inhibition promotes M2-type polarization. Trametinib and panobinostat also blocked M2-type macrophage polarization and concomitantly angiogenesis and fibrosis in models of wound healing and neovascular age-related macular degeneration in vivo. Thus, these pharmacologic inhibitors could be utilized therapeutically to selectively block IL4-induced macrophage polarization and reduce pathologic angiogenesis and fibrosis.
Project description:Macrophages polarize towards different subpopulations with distinct and partly antagonistic functions in various diseases. IFNγ/LPS-polarized M1-type macrophages can have antiangiogenic activity, whereas IL-4-induced M2-type macrophages can be proangiogenic and profibrotic. Therapeutic strategies to inhibit M2-type polarization while promoting M1-type polarization could serve to inhibit pathological angiogenesis and fibrosis. Here, by combining global quantitative time-course proteomics and phosphoproteomics with a small-molecule inhibitor screen we identify signaling events that promote specifically IL-4-induced and not IFNγ/LPS-induced macrophage polarization and found that the MEK inhibitor trametinib and the HDAC inhibitor panobinostat potently prevent M2-type macrophage polarization without inhibiting M1-type polarization. In contrast, selective B-Raf inhibition promotes M2-type polarization. Trametinib and panobinostat also blocked M2-type macrophage polarization and concomitantly angiogenesis and fibrosis in models of wound healing and neovascular age-related macular degeneration in vivo. Thus, these pharmacologic inhibitors could be utilized therapeutically to selectively block IL4-induced macrophage polarization and reduce pathologic angiogenesis and fibrosis.
Project description:The proteasome is a central regulatory hub for intracellular signaling by degrading numerous signaling mediators. Immunoproteasomes are specialized types of proteasomes known to be involved in shaping adaptive immune responses, but their role for innate immune signaling is elusive. Here, we analyzed immunoproteasome function for polarization of alveolar macrophages which are highly specialized tissue macrophages of the alveolar surface of the lung. Classical activation (M1 polarization) of primary alveolar macrophages by LPS/IFNγ transcriptionally induced all three immunoproteasome subunits LMP2, LMP7, and MECL-1. In contrast, IL-4 triggered alternative (M2) activation was accompanied by posttranscriptional upregulation of LMP2 and LMP7. Accordingly, immunoproteasome activity increased in M1 cells, and to some extent under M2 conditions. Analyzing the polarization capability from LMP7 deficient mice revealed no effect on the LPS/IFNγ triggered M1 profile, but uncovered a distorted M2 profile for IL-4 stimulated LMP7-/- alveolar macrophages as characterized by increased M2 marker gene expression and CCL17 cytokine release. This shift in immunoproteasome-dependent M2 polarization was accompanied by amplified AKT/STAT6 activation and IRF4 expression in LMP7-/- alveolar macrophages. IL-13 stimulation of LMP7 deficient cells induced a similar M2 skewed profile and IL4Rα protein expression was generally elevated in LMP7-/- alveolar macrophages, indicating that amplified IL4R signaling in immunoproteasome defective cells may contribute to augmented M2 polarization. Importantly, treatment with an LMP7-specific proteasome inhibitor recapitulated the findings of genetic LMP7 inactivation. Our results thus suggest a novel role of immunoproteasome function for regulating innate immune function of macrophages by limiting IL4R expression and signaling.
Project description:This model is based on:
Computational Modeling of the Crosstalk Between Macrophage Polarization and Tumor Cell Plasticity in the Tumor Microenvironment.
Abstract:
Tumor microenvironments contain multiple cell types interacting among one another via different signaling pathways. Furthermore, both cancer cells and different immune cells can display phenotypic plasticity in response to these communicating signals, thereby leading to complex spatiotemporal patterns that can impact therapeutic response. Here, we investigate the crosstalk between cancer cells and macrophages in a tumor microenvironment through in silico (computational) co-culture models. In particular, we investigate how macrophages of different polarization (M1 vs. M2) can interact with epithelial-mesenchymal plasticity of cancer cells, and conversely, how cancer cells exhibiting different phenotypes (epithelial vs. mesenchymal) can influence the polarization of macrophages. Based on interactions documented in the literature, an interaction network of cancer cells and macrophages is constructed. The steady states of the network are then analyzed. Various interactions were removed or added into the constructed-network to test the functions of those interactions. Also, parameters in the mathematical models were varied to explore their effects on the steady states of the network. In general, the interactions between cancer cells and macrophages can give rise to multiple stable steady-states for a given set of parameters and each steady state is stable against perturbations. Importantly, we show that the system can often reach one type of stable steady states where cancer cells go extinct. Our results may help inform efficient therapeutic strategies.