Efferocytosis induces a novel SLC program to promote glucose uptake and lactate release
Ontology highlight
ABSTRACT:
ORGANISM(S): Cricetulus griseus
PROVIDER: GSE119273 | GEO | 2018/11/30
REPOSITORIES: GEO
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Project description:Phagocytes in different tissues recognize and remove apoptotic cells via the process of efferocytosis. Although it is well-established that efferocytosis elicits an anti-inflammatory response by phagocytes, the molecules and mechanisms that enforce this response in phagocytes are still being defined. In attempting to decipher gene programs induced after a phagocyte ingests a dying cell, we uncovered a chloride-sensing signaling pathway that controls both the ‘appetite’ of a phagocyte and how a phagocyte responds after corpse uptake. First, we noted that within phagocytes that have ingested a corpse, the solute carrier 12 (SLC12) family members SLC12A2 and SLC12A4 are actively modulated. Interfering with SLC12A2, either genetically or pharmacologically, led to significantly enhanced corpse uptake per phagocyte, while loss of SLC12A4 inhibited corpse uptake. Interestingly, when phagocytes with disrupted SLC12A2 engulfed apoptotic corpses, the typical homeostatic efferocytosis signature was perturbed, characterized by loss of the canonical anti-inflammatory program and replaced by pro-inflammatory and oxidative stress-associated gene programs. In further mechanistic studies, we observed efferocytosis was also regulated by the chloride-sensing pathway upstream of SLC12A2, including the kinases WNK1-OSR1-SPAK, and this involved chloride entry/exit across the plasma membrane of phagocytes during corpse engulfment. We also show that the ‘switch’ to pro-inflammatory sensing of apoptotic cells is specifically due to disruption of the chloride-sensing pathway and not due to corpse overload or poor degradation, and that the pro-inflammatory gene signature can be reversed using a chloride ionophore. Collectively, these data identify the WNK1-OSR1-SPAK-SLC12A2/SLC12A4 chloride-sensing pathway and chloride flux in phagocytes as key modifiers of how a phagocyte interprets an engulfed apoptotic corpse.
2020-03-24 | GSE131860 | GEO
Project description:Macrophages can adjust their phenotype and function in response to environmental cues, such as encountering apoptotic cells or pathogens. After tissue injury or inflammation, macrophages must successively engulf and process multiple apoptotic corpses (via efferocytosis) to achieve tissue homeostasis. How macrophages may rapidly adapt their transcription to achieve continued corpse uptake is incompletely understood. Transcriptional pause/release is an evolutionarily conserved process wherein RNA polymerase II (Pol II), after initiating transcription for 20-60 nucleotides, gets ‘paused’ for seconds to hours; paused Pol II then gets ‘released’ to complete transcription to make full-length mRNA. Here we show that macrophages, within minutes of corpse encounter, use transcriptional pause/release as a mechanism to unleash a rapid transcriptional response. For human and murine macrophages, the Pol II pause/release was crucial for continued efferocytosis of corpses in vitro and in vivo. Interestingly, blocking Pol II pause/release did not impede FcR-mediated phagocytosis, yeast uptake, or bacterial phagocytosis. Integrating data from three complementary genomic approaches of PRO-seq, RNA-seq, and ATAC-seq on efferocytic macrophages at different time points, we found that Pol II pause/release controls expression of select transcription factors and downstream target genes. Further mechanistic studies on transcription factor Egr3, one of the genes prominently affected by pause/release, uncovered Egr3-related reprogramming of macrophage genes involved in cytoskeleton and corpse processing. Via lysosomal probes and a newly designed genetic fluorescent reporter, we identify a key role for pause/release in phagosome acidification during efferocytosis. Further, microglia from egr3-deficient zebrafish embryos displayed reduced phagocytosis of apoptotic neurons and fewer maturing endosomes, supporting a defect in corpse processing. Collectively, these data advance a novel concept that macrophages use Polymerase II pause/release as a mechanism to rapidly alter their transcriptional programs for efficient processing of the ingested apoptotic corpse and for successive efferocytosis.
2024-01-25 | GSE253574 | GEO
Project description:Macrophages can adjust their phenotype and function in response to environmental cues, such as encountering apoptotic cells or pathogens. After tissue injury or inflammation, macrophages must successively engulf and process multiple apoptotic corpses (via efferocytosis) to achieve tissue homeostasis. How macrophages may rapidly adapt their transcription to achieve continued corpse uptake is incompletely understood. Transcriptional pause/release is an evolutionarily conserved process wherein RNA polymerase II (Pol II), after initiating transcription for 20-60 nucleotides, gets ‘paused’ for seconds to hours; paused Pol II then gets ‘released’ to complete transcription to make full-length mRNA. Here we show that macrophages, within minutes of corpse encounter, use transcriptional pause/release as a mechanism to unleash a rapid transcriptional response. For human and murine macrophages, the Pol II pause/release was crucial for continued efferocytosis of corpses in vitro and in vivo. Interestingly, blocking Pol II pause/release did not impede FcR-mediated phagocytosis, yeast uptake, or bacterial phagocytosis. Integrating data from three complementary genomic approaches of PRO-seq, RNA-seq, and ATAC-seq on efferocytic macrophages at different time points, we found that Pol II pause/release controls expression of select transcription factors and downstream target genes. Further mechanistic studies on transcription factor Egr3, one of the genes prominently affected by pause/release, uncovered Egr3-related reprogramming of macrophage genes involved in cytoskeleton and corpse processing. Via lysosomal probes and a newly designed genetic fluorescent reporter, we identify a key role for pause/release in phagosome acidification during efferocytosis. Further, microglia from egr3-deficient zebrafish embryos displayed reduced phagocytosis of apoptotic neurons and fewer maturing endosomes, supporting a defect in corpse processing. Collectively, these data advance a novel concept that macrophages use Polymerase II pause/release as a mechanism to rapidly alter their transcriptional programs for efficient processing of the ingested apoptotic corpse and for successive efferocytosis.
2024-01-25 | GSE253577 | GEO
Project description:Macrophages can adjust their phenotype and function in response to environmental cues, such as encountering apoptotic cells or pathogens. After tissue injury or inflammation, macrophages must successively engulf and process multiple apoptotic corpses (via efferocytosis) to achieve tissue homeostasis. How macrophages may rapidly adapt their transcription to achieve continued corpse uptake is incompletely understood. Transcriptional pause/release is an evolutionarily conserved process wherein RNA polymerase II (Pol II), after initiating transcription for 20-60 nucleotides, gets ‘paused’ for seconds to hours; paused Pol II then gets ‘released’ to complete transcription to make full-length mRNA. Here we show that macrophages, within minutes of corpse encounter, use transcriptional pause/release as a mechanism to unleash a rapid transcriptional response. For human and murine macrophages, the Pol II pause/release was crucial for continued efferocytosis of corpses in vitro and in vivo. Interestingly, blocking Pol II pause/release did not impede FcR-mediated phagocytosis, yeast uptake, or bacterial phagocytosis. Integrating data from three complementary genomic approaches of PRO-seq, RNA-seq, and ATAC-seq on efferocytic macrophages at different time points, we found that Pol II pause/release controls expression of select transcription factors and downstream target genes. Further mechanistic studies on transcription factor Egr3, one of the genes prominently affected by pause/release, uncovered Egr3-related reprogramming of macrophage genes involved in cytoskeleton and corpse processing. Via lysosomal probes and a newly designed genetic fluorescent reporter, we identify a key role for pause/release in phagosome acidification during efferocytosis. Further, microglia from egr3-deficient zebrafish embryos displayed reduced phagocytosis of apoptotic neurons and fewer maturing endosomes, supporting a defect in corpse processing. Collectively, these data advance a novel concept that macrophages use Polymerase II pause/release as a mechanism to rapidly alter their transcriptional programs for efficient processing of the ingested apoptotic corpse and for successive efferocytosis.
2024-01-25 | GSE253576 | GEO
Project description:Efferocytosis is critical for tissue homeostasis, as its deregulation is associated with several autoimmune pathologies. While engulfing apoptotic cells, phagocytes activate transcription factors, such as peroxisome proliferator-activated receptors (PPAR) or liver X receptors (LXR) that orchestrate metabolic, phagocytic, and inflammatory responses towards the ingested material. Coordination of these transcription factors in efferocytotic human macrophages (MF) is not fully understood. In this study, we evaluated the transcriptional profile of MF following the uptake of apoptotic Jurkat T cells using RNA-seq analysis. Results indicated upregulation of PPAR and LXR pathways but downregulation of sterol regulatory element-binding proteins (SREBP) target genes. Pharmacological inhibition and RNA interference pointed to LXR and PPARdelta as relevant transcriptional regulators, while PPARdelta did not substantially contribute to gene regulation. Mechanistically, lysosomal digestion and lysosomal acid lipase (LIPA) were required for PPAR and LXR activation, while PPARdelta activation also demanded an active lysosomal phospholipase A2 (PLA2G15). Pharmacological interference with LXR signaling attenuated ABCA1-dependent cholesterol efflux from efferocytotic MF, but suppression of inflammatory responses following efferocytosis occurred independently of LXR and PPARdelta. These data provide mechanistic details on LXR and PPARdelta activation in efferocytotic human MF.
2021-05-26 | GSE169160 | GEO
Project description:Professional phagocytes (such as macrophages) and non-professional phagocytes (such as epithelial cells) clear billions of apoptotic cells and particles on a daily basis. Since these phagocytes reside in proximity in most tissues, whether cross-communication exists between them during cell clearance, and how this might impact inflammation are not known. Here, we show that macrophages, via the release of a soluble growth factor and microvesicles, redirect the type of particles engulfed by non-professional phagocytes and influence their inflammatory response. During apoptotic cell engulfment or in response to inflammation-associated cytokines, macrophages released insulin-like growth factor 1 (IGF-1). The binding of IGF-1 to its receptor on non-professional phagocytes redirected their phagocytosis, such that uptake of larger apoptotic cells was dampened while engulfment of microvesicles was enhanced. Macrophages were refractory to this IGF-1 mediated engulfment modulation. Macrophages also released microvesicles, whose uptake by epithelial cells, enhanced by IGF-1, led to decreased inflammatory responses by epithelial cells. Consistent with these observations, deletion of IGF-1 receptor in airway epithelial cells led to exacerbated lung inflammation after allergen exposure. These genetic and functional studies reveal a novel IGF-1 and microvesicle-dependent communication between macrophages and epithelial cells that can critically influence the magnitude of tissue inflammation in vivo.
2016-11-01 | GSE89049 | GEO
Project description:Poor wound healing due to dysregulated tissue repair responses can exacerbate and prolong disease. Successful tissue repair is critically dependent on the timely clearance of apoptotic cells by macrophages in a process termed efferocytosis. Mechanisms and factors that link these two fundamental processes are therefore of great interest. Herein, we observed that a subset of 12-lipoxygenase (ALOX12)-expressing macrophages upregulate the production of host protective autacoids termed maresin conjugates in tissue regeneration (MCTR) during efferocytosis. MCTRs in turn play autocrine and paracrine functions in enhancing the ability of both ALOX12-positive and surrounding ALOX12-negative macrophages to uptake apoptotic cells. These effects of ALOX12-positive macrophages and MCTRs in regulating apoptotic cells clearance was also observed at sites of high apoptotic cell burden in mouse and flatworm models, as the formation of these mediators was upregulated and abrogation of related ALOX activity in mice reduced the ability of macrophages to clear apoptotic cells. Furthermore, add-back of MCTRs rapidly enhanced the efferocytosis capability of macrophages in mice and planarian flatworms. Mechanistic studies in macrophages revealed that MCTRs modulated Rac1 signalling and glycolytic metabolism, two pathways crucial for effective efferocytosis, and enhanced efferocytosis-induced WNT ligand production. Inhibition of Rac1 abrogated the ability of MCTRs to enhance glucose uptake and efferocytosis in vitro, while inhibiting either Rac1, glycolysis, or WNT ligand production prevented MCTR-mediated enhancement of apoptotic cell clearance and tissue regeneration. Taken together, our findings identify a central role for ALOX12-expressing macrophages in the regulation of efferocytosis and tissue repair via the local formation of MCTRs.
2023-12-12 | PXD038390 | Pride
Project description:Apoptotic cell clearance (efferocytosis), a process essential for organismal homeostasis, is performed by phagocytes that inhabit a wide range of environments, including physiologic hypoxia. Here, we find macrophages, the predominant tissue-resident phagocyte, display enhanced efferocytosis under chronic hypoxia, characterized by increased internalization and accelerated degradation of apoptotic cells. Analysis of mRNA and protein programs revealed that chronic hypoxia induces two distinct but complimentary states in macrophages. The first, ‘primed’ state consists of concomitant induction of transcriptional and translational programs broadly associated with metabolism in apoptotic cell-naïve macrophages that persist during efferocytosis. The second, ‘poised’ state consists of transcription, but not translation, of phagocyte function programs in apoptotic cell-naïve macrophages that are subsequently translated during efferocytosis. We discovered that one such primed state consists of the efficient flux of glucose into a noncanonical pentose phosphate pathway (PPP) loop, whereby PPP-derived intermediates cycle back through the PPP to enhance production of NADPH. Mechanistically, we found that PPP-derived NADPH directly supports enhanced efferocytosis under chronic hypoxia via its role in phagolysosomal maturation, while simultaneously maintaining cellular redox homeostasis. Thus, macrophages adapt to chronic hypoxia by adopting states that both support cell fitness and ensure ability to rapidly and safely perform essential homeostatic functions.
2022-12-30 | GSE192969 | GEO
Project description:Efferocytosis induces a novel SLC program to promote glucose uptake and lactate release
| PRJNA488640 | ENA
Project description:The efficient clearance of dead and dying cells, also known as efferocytosis, is critical to maintain tissue homeostasis. In the bone marrow microenvironment (BMME), this role is primarily fulfilled by professional bone marrow macrophages, but recent work has shown that mesenchymal stromal cells (MSCs) act as a non-professional phagocyte within the BMME. However, little is known about the mechanism and impact of efferocytosis on MSCs in the BMME and on their function. To investigate this, we performed flow cytometric analysis of neutrophil uptake by ST2 cells, a murine bone marrow-derived stromal cell line, and in murine primary bone marrow-derived stromal cells. Transcriptional analysis showed that MSCs possess the necessary receptors and internal processing machinery to conduct efferocytosis, with Axl and Tyro3 serving as the main receptors, while MerTK was not expressed. Moreover, the expression of these receptors was modulated by efferocytic behavior, regardless of apoptotic target. MSCs derived from human bone marrow also demonstrated efferocytic behavior, showing that MSC efferocytosis is conserved. In all MSCs, efferocytosis impaired osteoblastic differentiation. Transcriptional analysis and functional assays identified downregulation in MSC mitochondrial function upon efferocytosis. Experimentally, efferocytosis induced mitochondrial fission in MSCs. Pharmacologic inhibition of mitochondrial fission in MSCs not only decreased efferocytic activity but also rescued osteoblastic differentiation, demonstrating that efferocytosis-mediated mitochondrial remodeling plays a critical role in regulating MSC differentiation. This work describes a novel function of MSCs as non-professional phagocytes within the BMME and demonstrates that efferocytosis by MSCs plays a key role in directing mitochondrial remodeling and MSC differentiation. Efferocytosis by MSCs may therefore be a novel mechanism of dysfunction and senescence. Since our data in human MSCs show that MSC efferocytosis is conserved, the consequences of MSC efferocytosis may impact the behavior of these cells in the human skeleton, including osteoporosis in aging.
2023-07-14 | GSE223281 | GEO