Similar Datasets
Project description:Here, we show that neutrophils infected with the bacterial pathogenPorphyromonas gingivalis (Pg) are internalized alive by macrophages in a manner that bypasses all known efferocytic receptor-ligand interactions. Live cell uptake was mediated by the proteolysis of neutrophil granule proteins by the Pg protease RgpB. Subsequent translocation and recognition of these RgpB-generated efferocytic ligands by macrophage complement receptor 3 (CR3) receptors led to the internalization of live neutrophils by macrophages. Contrary to the immunosuppression induced by apoptotic cells, efferocytosis of live neutrophils was highly inflammatory. Thus, our data show a novel immune subversion strategy employed by a bacterial pathogen that utilizes a previously unknown receptor-ligand interaction for the efferocytosis of live cells and consequently dysregulates the resolution of inflammation.
2025-08-25 | GSE264523 | GEO
Project description:Here, we show that neutrophils infected with the bacterial pathogenPorphyromonas gingivalis (Pg) are internalized alive by macrophages in a manner that bypasses all known efferocytic receptor-ligand interactions. Live cell uptake was mediated by the proteolysis of neutrophil granule proteins by the Pg protease RgpB. Subsequent translocation and recognition of these RgpB-generated efferocytic ligands by macrophage complement receptor 3 (CR3) receptors led to the internalization of live neutrophils by macrophages. Contrary to the immunosuppression induced by apoptotic cells, efferocytosis of live neutrophils was highly inflammatory. Thus, our data show a novel immune subversion strategy employed by a bacterial pathogen that utilizes a previously unknown receptor-ligand interaction for the efferocytosis of live cells and consequently dysregulates the resolution of inflammation.
2025-08-25 | GSE264522 | GEO
Project description:Erroneous efferocytosis of live neutrophils during infection prevents the resolution of inflammation
| PRJNA1103064 | ENA
Project description:Erroneous efferocytosis of live neutrophils during infection prevents the resolution of inflammation [RNAseq_dual_species]
| PRJNA1103070 | ENA
Project description:Erroneous efferocytosis of live neutrophils during infection prevents the resolution of inflammation [RNAseq_single_species]
| PRJNA1103071 | ENA
Project description:Here, we show that neutrophils infected with the bacterial pathogen Porphyromonas gingivalis (Pg) are internalized alive by macrophages in a manner that bypasses all known efferocytic receptor-ligand interactions with highly inflammatory outcomes. Mechanistically, proteolytic cleavage of neutrophil granule proteins by the Pg protease RgpB generated non-canonical ligands that were recognized by macrophage aMb2 (CR3) receptors, facilitating the efferocytosis of live neutrophils. Contrary to the immunosuppression induced by apoptotic cells, efferocytosis of Pg-infected or RgpB-treated live neutrophils was highly inflammatory, with significant delays in efferosomal maturation. Thus, our data show a novel immune subversion strategy employed by a bacterial pathogen that utilizes a previously unknown receptor-ligand interaction for the efferocytosis of live cells and consequently dysregulates the resolution of inflammation.
2025-07-14 | PXD051073 | Pride
Project description:Regulatory T (Treg) cell responses and apoptotic cell clearance (efferocytosis) represent critical arms of the inflammation resolution response. We sought to determine whether these processes might be linked through Treg-cell-mediated enhancement of efferocytosis. In zymosan-induced peritonitis and lipopolysaccharide-induced lung injury, Treg cells increased early in resolution, and Treg cell depletion decreased efferocytosis. In advanced atherosclerosis, where defective efferocytosis drives disease progression, Treg cell expansion improved efferocytosis. Mechanistic studies revealed the following sequence: (1) Treg cells secreted interleukin-13 (IL-13), which stimulated IL-10 production in macrophages; (2) autocrine-paracrine signaling by IL-10 induced Vav1 in macrophages; and (3) Vav1 activated Rac1 to promote apoptotic cell engulfment. In summary, Treg cells promote macrophage efferocytosis during inflammation resolution via a transcellular signaling pathway that enhances apoptotic cell internalization. These findings suggest an expanded role of Treg cells in inflammation resolution and provide a mechanistic basis for Treg-cell-enhancement strategies for non-resolving inflammatory diseases.
| S-EPMC6192849 | biostudies-literature
Project description:Background Neutrophils play a major role in inflammation after myocardial ischemia-reperfusion (I/R) injury. The effects of mesenchymal stem cells (MSCs) on neutrophils in I/R are complex and not fully understood. This study was designed to investigate the effects and mechanism of MSCs on alleviating myocardial I/R injury in rats. Methods and Results MSCs induced M2 macrophages polarization in vitro and enhanced macrophage efferocytosis of apoptotic neutrophils, measured by fluorescence-activated cell sorting analysis and immunofluorescence staining. Rats myocardial I/R were induced by transient ligation of left anterior descending coronary. Adipose-derived MSCs or vehicle were infused at initiation (immediate after reperfusion) or peak of inflammation (24 hours after I/R). Hematoxylin and eosin, 2,3,5-triphenyltetrazolium chloride/Evans Blue staining and immunofluorescence staining were applied within 72 hours after cell infusion. Cardiac function was assessed by echocardiography and left cardiac catheterization analysis at 28 days post-operation. MSCs infused immediately and 24 hours later both markedly ameliorated myocardial I/R injury, and immediate infusion had more significant outcome. These improvements were associated with neutrophils infiltration, measured by fluorescence-activated cell sorting analysis and immunofluorescence staining. When infused immediately, MSCs did not significantly change neutrophil number at 24 hours but CD11b expression was significantly higher. When infused at 24 hours, MSCs markedly decreased neutrophil number by enhanced M2 macrophage infiltration and macrophage efferocytosis of neutrophils within 72 hours. Conclusions Efferocytosis is pivotal to relieve neutrophil-mediated I/R injury and initial the immune response for healing. MSCs infusion improves cardiac function in rats after myocardial I/R via the possible mechanism of enhancing M2 macrophages-induced efferocytosis of apoptotic neutrophils.
| S-EPMC7335576 | biostudies-literature
Project description:Nonresolving inflammation perpetuated by innate leukocytes is involved in the pathogenesis of unstable atherosclerosis. However, the role and regulation of neutrophils related to nonresolving inflammation and atherosclerosis are poorly understood. We report herein that chronic subclinical endotoxemia, a risk factor for atherosclerosis, skewed neutrophils into a nonresolving inflammatory state with elevated levels of inflammatory mediators (Dectin-1, MMP9, and LTB4) and reduced levels of homeostatic mediators (LRRC32, TGFβ, and FPN). The polarization of neutrophils was due to ROS-mediated activation of oxCAMKII, caused by altered peroxisome homeostasis and reduced lysosome fusion. Application of 4-phenylbutyrate (4-PBA) enhanced peroxisome homeostasis of neutrophils, reduced oxCAMKII, and rebalanced the expression profiles of pro- and anti-inflammatory mediators. Adoptive transfer of neutrophils programmed by subclinical endotoxemia rendered exacerbated atherosclerosis. In contrast, transfer of ex vivo programmed neutrophils by 4-PBA reduced the pathogenesis of atherosclerosis. Our data define novel neutrophil dynamics associated with the progression and regression of atherosclerosis.
| S-EPMC6365109 | biostudies-literature
Project description:Community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) pose a significant threat to human health. Polymorphonuclear leukocytes (PMN) are the first responders during staphylococcal infection, but 15-50% of the initial ingested inoculum survives within the PMN phagosome and likely contributes directly or indirectly to disease pathogenesis. We hypothesize that surviving intracellular CA-MRSA undermine effective phagocyte-mediated defense by causing a decrease in macrophage uptake of PMN containing viable S. aureus and by promoting PMN lysis. In support of this hypothesis, PMN harboring viable CA-MRSA strain USA300 (PMN-SA) upregulated the "don't eat me" signal CD47, remained bound to the surface, and were inefficiently ingested by macrophages. In addition, coculture with PMN-SA altered the macrophage phenotype. Compared to macrophages fed USA300 alone, macrophages challenged with PMN-SA produced more IL-8 and less IL-1 receptor antagonist, TNF-α, activated caspase-1, and IL-1β. Although they exhibited some features of apoptosis within 3 h following ingestion of S. aureus, including phosphatidylserine exposure and mitochondrial membrane depolarization, PMN-SA had sustained levels of proliferating cell nuclear Ag expression, absence of caspase activation, and underwent lysis within 6 h following phagocytosis. PMN lysis was dependent on receptor-interacting protein 1, suggesting that PMN-SA underwent programmed necrosis or necroptosis. These data are the first demonstration, to our knowledge, that bacteria can promote sustained expression of proliferating cell nuclear Ag and that human PMN undergo necroptosis. Together, these findings demonstrate that S. aureus surviving within PMN undermine the innate immune response and may provide insight into the pathogenesis of S. aureus disease.
| S-EPMC4011196 | biostudies-literature