Gut complement induced by the microbiota combats pathogens and spares commensals
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE250268 | GEO | 2024/01/16
REPOSITORIES: GEO
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Project description:Canonically, the complement system is known for its rapid response to remove microbes in the bloodstream. However, relatively little is known about a functioning complement system on intestinal mucosal surfaces. Herein we report the local synthesis of complement component 3 (C3) in the gut, primarily by stromal cells. C3 is expressed upon commensal colonization, is regulated by the composition of the microbiota in healthy humans and mice, leading to an individual host’s specific luminal C3 levels. The absence of membrane attack complex (MAC) components in the gut ensures that C3 deposition does not result in the lysis of commensals. Pathogen infection triggers the immune system to recruit neutrophils to the infection site for pathogen clearance. Basal C3 levels directly correlate with protection against enteric infection. Our study reveals the gut complement system as a novel innate immune mechanism acting as a vigilant sentinel that combats pathogens and spares commensals.
2023-12-04 | GSE248940 | GEO
Project description:The intestinal microbiota fundamentally influences the development of a normal intestinal physiology and education and functioning of the mucosal immune system. Using the C. rodentium carrier model of germfree mice (GF), we found that colonization of adult GF with 14 selected commensals (OMM12+MC2) was sufficient to convert a carriers into responders through maturation of intestinal crypts, increasing intestinal angiogenesis and stimulation of the immune system. While the immature colon of C. rodentium infected GF did not allow sufficient extravasation of neutrophils into the gut lumen, colonization with these commensals triggered activation and proliferation of endothelial cells, enabling granulocytes to transmigrate into the gut lumen. Enhanced angiogenesis and morphological maturation development of the intestine was most likely due to sensing of commensals by Paneth cells and subsequent secretion of antimicrobial peptides and angiogenetic factors. This demonstrates the therapeutic value of few commensal bacteria to complete morphological and immunological maturation in of the adult intestinal mucosa enabling rendering this organ immunocompetent against infections and responsive to therapies.
2021-09-09 | GSE180156 | GEO
Project description:Plants are colonized by a variety of microorganisms, the plant microbiota. In the phyllosphere, the above-ground parts of plants, bacteria are the most abundant inhabitants. Most of these microorganisms are not pathogenic and the plant responses to commensals or to pathogen infection in the presence of commensals are not well understood. We report the Arabidopsis leaf transcriptome after 3 to 4 weeks of colonization by Methylobacterium extorquens PA1 and Sphingomonas melonis Fr1, representatives of two abundant genera in the phyllosphere, compared to axenic plants. In addition, we also sequenced the transcriptome of Arabidopsis 2 and 7 days after spray-infection with a low dose of P. syringae DC3000 and in combination with the commensals.
2016-06-05 | E-MTAB-4683 | biostudies-arrayexpress
Project description:Acute gastrointestinal infection with intracellular pathogens like Salmonella Typhimurium triggers the release of the proinflammatory cytokine interleukin 1β (IL-1β). However, the role of IL-1β in intestinal defense against Salmonella remains unclear. Here, we show that IL-1b production is detrimental during Salmonella infection. Mice lacking IL-1b (IL-1b -/-) failed to recruit neutrophils to the gut during infection, which reduced tissue damage and prevented depletion of short-chain fatty acid-producing commensals. Changes in epithelial cell metabolism that typically support pathogen expansion, such as switching energy production from fatty acid oxidation to fermentation, were absent in infected IL-1b -/- mice which inhibited Salmonella expansion. Additionally, we found that IL-1b induces expression of complement anaphylatoxins and suppresses the complement-inactivator Carboxypeptidase N (CPN1). Disrupting this process via IL-1b loss prevented mortality in Salmonella-infected IL-1b -/- mice. Finally, we found that IL-1b expression correlates with expression of the complement receptor in patients suffering from sepsis, but not uninfected patients and healthy individuals. Thus, Salmonella exploits IL-1b signaling to outcompete commensal microbes and establish gut colonization. Moreover, our findings identify the intersection of IL-1b signaling and the complement system as key host factors involved in controlling mortality during invasive Salmonellosis.
2024-01-08 | GSE252070 | GEO
Project description:Acute gastrointestinal infection with intracellular pathogens like Salmonella Typhimurium triggers the release of the proinflammatory cytokine interleukin 1β (IL-1β). However, the role of IL-1β in intestinal defense against Salmonella remains unclear. Here, we show that IL-1b production is detrimental during Salmonella infection. Mice lacking IL-1b (IL-1b -/-) failed to recruit neutrophils to the gut during infection, which reduced tissue damage and prevented depletion of short-chain fatty acid-producing commensals. Changes in epithelial cell metabolism that typically support pathogen expansion, such as switching energy production from fatty acid oxidation to fermentation, were absent in infected IL-1b -/- mice which inhibited Salmonella expansion. Additionally, we found that IL-1b induces expression of complement anaphylatoxins and suppresses the complement-inactivator Carboxypeptidase N (CPN1). Disrupting this process via IL-1b loss prevented mortality in Salmonella-infected IL-1b -/- mice. Finally, we found that IL-1b expression correlates with expression of the complement receptor in patients suffering from sepsis, but not uninfected patients and healthy individuals. Thus, Salmonella exploits IL-1b signaling to outcompete commensal microbes and establish gut colonization. Moreover, our findings identify the intersection of IL-1b signaling and the complement system as key host factors involved in controlling mortality during invasive Salmonellosis.
2024-01-08 | GSE252069 | GEO
Project description:Replication-deficient adenovirus (Ad) type 5 capsids induce potent host innate immune responses. One system pivotal in host innate immune defense is the complement system. Intriguingly, excessive or inappropriate complement activation can result in extreme tissue damage and systemic inflammatory responses similar to those noted immediately after high dose systemic Ad vector injections. To determine if the complement system has a significant role in intensifying Ad-associated acute toxicities, we compared complement deficient (C3-knockout (KO)) mice responses to those of wild type (WT) mice following systemic challenge with Ad vectors. We noted not only thrombocytopenia and rapid increases in plasma IL-6, IFN-γ, TNF-α, and IL-12 levels previously reported after high dose Ad injections into WT mice, but also induction of cytokines IL-2, IL-4, IL-5 and IL-10, G-CSF and GM-CSF, and chemokines KC (CXCL1) and MIP-1. This expanded innate response “profile” was significantly blunted in Ad injected C3-KO mice, with a near complete avoidance of thrombocytopenia. Further validation for complement’s critical role in perturbing these innate responses against Ad were noted after comparison of gene specific RNA transcription levels in C3-KO to WT mice livers. Finally, these disparities were not attributed to a diminished ability of the Ad vectors to transduce C3-KO mice hepatocytes. These results suggest that Ad capsid interaction with the mammalian complement system may exacerbate the toxicity of systemic Ad injections, and thus represents a future target for manipulation in efforts to improve the efficacy and safety profile of Ad mediated gene delivery. Keywords: adenovirus, complement system, time course, innate immune response, toxicity
2006-02-15 | GSE4128 | GEO
Project description:Perioperative neurocognitive disorder (PNDs) can commonly occur after major surgery in at risk patients and its occurrence increases medical healthcare burdens and even mortality. Accumulating evidence points to neuroinflammation being pivotal to the pathogenesis of these conditions. The complement cascade contributes to neuroinflammatory responses in the central nervous system (CNS) and complement C3 has been implicated in the manifestation of cognitive deficits in several neurological conditions. Neurotoxic reactive astrocytes function differently to their non-activated counterparts and release complement components in response to pathological triggers. We observed previously that surgery induces a rapid rise and then fall in cytokines but a more sustained glial activation response that coincided with postoperative cognitive impairment. In this study, we explored the relationship between the expression of complement C3, glial activation, and cognitive deficits. Using a murine model of surgery, we characterized the transcriptional profiles of hippocampal astrocytes after surgery and examined the effects of C3 suppression on the neuroinflammatory response and cognitive performance. There was a delayed but sustained rise in hippocampal C3 of astrocytic in origin after surgery which corresponded with the onset of cognitive decline. Furthermore, the A1 or the neurotoxic phenotype predominated in this postoperative astrocytic activation, and these cells have a distinct transcriptional profile including C3 upregulation. Suppression of C3 inhibited synaptic phagocytosis by microglia and attenuated postoperative cognitive impairment. Therefore, C3 from reactive astrocytes appear central to the development of cognitive dysfunction associated with postoperative neuroinflammation.
2024-03-13 | GSE199318 | GEO
Project description:Complement has emerged as a component of tumor promoting inflammation. We conducted a systematic assessment of the role of complement activation and effector pathways in sarcomas. C3-/-, MBL1/2-/- and C4-/- mice showed reduced susceptibility to 3-methylcholanthrene sarcomagenesis and transplanted sarcomas, whereas C1q and factor B deficiency had marginal effects. Complement 3a receptor (C3aR), but not C5aR1 and C5aR2, deficiency mirrored the phenotype of C3-/- mice. C3 and C3aR deficiency were associated with reduced accumulation and functional skewing of tumor-associated macrophages, increased T cell activation and response to anti-PD-1 therapy. Transcriptional profiling of sarcoma infiltrating macrophages and monocytes revealed the enrichment of MHC II-dependent antigen presentation pathway in C3-deficient cells. In patients, C3aR expression correlated with a macrophage population signature and C3 deficiency-associated signatures predicted better clinical outcome. These results suggest that the lectin pathway and C3a/C3aR axis are key components of complement and macrophage-mediated sarcoma promotion and immunosuppression.
2020-11-24 | GSE141692 | GEO
Project description:The gastrointestinal nematode Ostertagia ostertagi is one of major causal agents that contribute to production inefficiency in cattle industry in the temperate region of the world. One of pathophysiological factors that lead to reduced weight gain and milk yield is altered gastrointestinal functions, resulting from considerable tissue damage in the abomasal mucosa during infections. Protective immunity to Ostertagia ostertagi infections in cattle develops very slowly. Resistance to reinfection becomes manifest only after a prolonged period of exposure. Mechanisms underlying the development of protective immunity remain largely unexplored. Immune animals, with significantly reduced worm burdens, were developed after multiple drug-attenuated experimental infections and were compared to the primary infected group and their respective uninfected controls. In this study, transcriptomic analysis identified 3 signaling pathways, the complement system, leukocyte extravasation and acute phase responses, significantly impacted during both primary and repeat infections. The markedly increased mRNA levels of complement components C3, factor B (CFB), and factor I (CFI) in the abomasal mucosa of the infected cattle were confirmed using quantitative PCR. Western blot analysis established the presence of elevated levels of activated C3 proteins in the mucosa. One of the iniators of local complement activation could be related with secretory IgA and IgM because infections significantly upregulated expression of J chain (IGJ) as well as polymeric Ig receptor (PIGR) and an IgM-specific receptor (FAIM3), suggesting sustained increase in both synthesis and transepithelial transport of IgA and IgM during the infection. The elevated levels of pro-inflammatory cytokines, such as IL-4 and IL-1β, during the infection may be involved in gene regulation of complement components. Our data suggested enhanced tissue repair and mucin secretion in immune animals may also contribute to protective immunity. Our results presented the first piece of evidence that local complement activation may be involved in the development of long term protective immunity and provided a novel mechanistic insight into resistance against Ostertagia ostertagi in cattle. There were four treatment groups: naive control (never infected), primary infection, drug-attenuated control, and drug-attenuated 5th reinfection. Each group had 4 biolgical replicates. A total of 16 arrays were used for this experiment. The 2 major contrast were 1). The primary infection vs naive control; and 2). The drug-attenuated 5th reinfection vs the drug-attenuated control.
2010-05-05 | E-GEOD-20927 | biostudies-arrayexpress
Project description:After myocardial infarction (MI), the heart fails to renew, and the cardiac microenvironment is irreversibly disrupted. Inactivation of the Hippo signaling pathway can rebuild the post ischemic microenvironment and improve cardiac function. We investigated spatially resolved cellular relationships of neonatal and adult renewal-competent hearts to gain insight into inefficient mammalian heart renewal. Spatial transcriptomics (ST) and single-cell sequencing of adult control hearts and hearts expressing YAP5SA, an active version of the Hippo signaling pathway effector YAP, which models heart renewal, revealed a conserved, renewal-competent cardiomyocyte (CM) population in control hearts and amplified in YAP5SA hearts. This CM population was also found in the wildtype, renewal competent neonatal heart after myocardial infarction, as well as the adult human heart. Cardiac fibroblasts (CFs), expressing complement C3, colocalized with these CMs. In YAP5SA hearts and neonatal hearts post-MI, macrophages (MPs) expressing complement receptor C3ar1 also colocalized, creating a pro-renewal niche composed of the CM, CF and MP triad. Both C3 and C3ar1 loss-of-function in YAP5SA hearts similarly suppressed heart renewal, indicating that C3-expressing CFs, C3ar1-expressing MPs, and complement system signaling play a direct role in heart renewal
2024-01-11 | GSE217828 | GEO