Apoptotic cells actively release metabolite messanger with anti-inflammatory properties
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ABSTRACT:
PROVIDER: PRJNA545309 | ENA |
REPOSITORIES: ENA
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Project description:Apoptosis accounts for ~ 90% of homeostatic cell turnover in the body1. While caspase-dependent apoptosis is known to influence immune tolerance, induction of cell proliferation, and tissue regeneration2-4, how these apoptotic cells contribute to such diverse effects is less understood. Soluble factors released from apoptotic cells could be a means of ‘talking’ to healthy cells in the tissue neighborhood. While a few phagocyte-attracting ‘find-me’ signals released from apoptotic cells are known5, the larger ‘metabolite secretome’ from apoptotic cells is not yet defined. Here, via unbiased profiling of the apoptotic cell secretome, we identified 123 metabolites that are specifically released during apoptosis, while cells still retain membrane integrity. Release of ~25 of these metabolites is dependent on Pannexin 1 (Panx1) channels, which are opened by caspase-dependent cleavage during apoptosis. Interestingly, one of the Panx1-dependent metabolites from apoptotic cells is spermidine, a polyamine whose release could be, in part, due to the continued metabolic activity of dying cells. RNAseq analysis of healthy cells exposed to the apoptotic secretome revealed Panx1-dependent gene programs, including genes linked to suppression of inflammation, cell proliferation, and wound healing. Analysis of the apoptotic secretome across cell types and different apoptotic stimuli, identified a core “set” of 8 Panx1-dependent metabolites. Strikingly, a selected cocktail of these metabolites demonstrated significant immunosuppressive effects by potently reducing disease severity in an inflammatory arthritis model and a lung graft rejection model. Collectively, these data advance the concept that apoptotic cells are not ‘inert’ corpses waiting for removal by phagocytes, but rather they actively communicate with the tissue environment through their metabolite secretome, with implications in tissue inflammation.
2020-03-19 | GSE131906 | GEO
Project description:Cells release nano-sized membrane vesicles that are involved in intercellular communication by transferring biological information between cells. It is generally accepted that cells release at least three types of these extracellular vesicles (EVs): apoptotic bodies, microvesicles and exosomes. Whilst exosomes are assumed to be a homogenous population of EVs, they have a wide range of putative functions. Therefore, we hypothesized that cells release subpopulations of exosomes with distinct molecular compositions and functional properties. Exosomes were isolated from conditioned medium by differential ultracentrifugation. Sucrose density gradient centrifugation of the resulting exosome pellet revealed the presence of two distinct subpopulations, one smaller, slow migrating population (HD-Exo), and one fast migrating, larger population (LD-Exo). Interestingly, the exosome subpopulations were found to have differential effects on gene expression in recipient endothelial cells. In conclusion, we demonstrate that cells release distinct subpopulations of exosomes with unique biophysical properties and molecular compositions that elicit differential effects on recipient cells. Our data supports the heterogeneous nature of exosomes. It also highlights the importance of better discrimination between subpopulations to allow more detailed studies on exosome biology and function, and assist in the development of exosome-based diagnostics and therapeutics.
2016-04-30 | GSE72351 | GEO
Project description:Purpose: Compare the RNA content of apoptotic human umbilical vein endothelial cells (HUVECs)-released vesicles: 1) Apoptotics bodies and 2) Apoptotic Exo-like vesicles, which are immunogenic and promote autoimmunity. Results: The transcriptome of ApoExos was unique with regards to its genomic origin, nucleotide composition and secondary structure. We show that ApoExos essentially contain non-ribosomal non-coding RNAs, among which 89% are derived from viral-like endogenous retroelements (EREs). ApoExos are also enriched in U-rich linear nucleotide sequences and Alus repeats. Conclusion: Our work demonstrates that apoptotic endothelial cells release EVs loaded with RNAs recognized by RLRs and endosomal TLRs (TLR3, TLR7 and TLR8), and are therefore tailor-made for initiation of innate immune responses and autoimmunity.
2019-05-10 | GSE119108 | GEO
Project description:Apoptotic endothelial cells release small extracellular vesicles loaded with immunostimulatory viral-like RNAs
| PRJNA488132 | ENA
Project description:Senescent cells drive age-related tissue dysfunction partially via the induction of a chronic senescence-associated secretory phenotype (SASP). Mitochondria are major regulators of the SASP; however, the underlying mechanisms have not been elucidated. Mitochondria also control apoptosis, a cell fate generally perceived as distinct from cellular senescence, which is apoptosis resistant. Here, we show that mitochondrial outer membrane permeability (MOMP) occurring in a small subset of mitochondria is a feature of cellular senescence. This process, called minority MOMP (miMOMP), depends on the formation of BAX and BAK macropores and results in release of mitochondrial DNA (mtDNA) into the cytosol, which in turn activates the cGAS/STING pathway, a major regulator of the SASP. Importantly, we found that inhibition of MOMP in vivo decreases inflammatory markers and improves healthspan parameters in aged mice. Our results propose the novel concept that apoptosis and senescence are regulated by similar mitochondrial-dependent mechanisms, and that sub-lethal mitochondrial apoptotic stress is a major driver of the SASP. We also provide proof-of-concept that inhibition of miMOMP may be a new therapeutic avenue to improve healthspan.
2023-08-16 | GSE196610 | GEO
Project description:Persistent endothelial injury promotes maladaptive responses by favoring the release of factors leading to perturbation in vascular homeostasis and tissue architecture. Caspase-3 dependent death of microvascular endothelial cells leads to the release of unique apoptotic exosome-like vesicles (ApoExo). Here, we evaluate the impact of ApoExo on endothelial gene expression and function in the context of a pro-apoptotic stimulus. Endothelial cells exposed to ApoExo differentially express genes involved in cell death, inflammation, differentiation, and cell movement. Endothelial cells exposed to ApoExo showed inhibition of apoptosis, improved wound closure along with reduced angiogenic activity and reduced expression of endothelial markers consistent with the first phase of endothelial-to-mesenchymal transition (endoMT). ApoExo interaction with endothelial cells also led to NF-κB activation. NF-κB is known to participate in endothelial dysfunction in numerous diseases. Silencing NF-κB reversed the anti-apoptotic effect and the pro-migratory state and prevented angiostatic properties and CD31 downregulation in endothelial cells exposed to ApoExo. This study identifies vascular injury-derived extracellular vesicles (ApoExo) as novel drivers of NF-κB activation in endothelial cells and demonstrates the pivotal role of this signaling pathway in coordinating ApoExo-induced functional changes in endothelial cells. Hence, targeting ApoExo-mediated NF-κB activation in endothelial cells opens new avenues to prevent endothelial dysfunction.
2019-12-11 | GSE141731 | 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: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