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Correa GB, Freire CA, Dibo M, Huerta-Cantillo J, Navarro-Garcia F, Barbosa AS, Elias WP, Moraes CTP. Plasmid-encoded toxin of Escherichia coli cleaves complement system proteins and inhibits complement-mediated lysis in vitro. Front Cell Infect Microbiol 2024; 14:1327241. [PMID: 38371299 PMCID: PMC10869522 DOI: 10.3389/fcimb.2024.1327241] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/08/2024] [Indexed: 02/20/2024] Open
Abstract
Plasmid-encoded toxin (Pet) is an autotransporter protein of the serine protease autotransporters of Enterobacteriaceae (SPATE) family, important in the pathogenicity of Escherichia coli. The pet gene was initially found in the enteroaggregative E. coli (EAEC) virulence plasmid, pAA2. Although this virulence factor was initially described in EAEC, an intestinal E. coli pathotype, pet may also be present in other pathotypes, including extraintestinal pathogenic strains (ExPEC). The complement system is an important defense mechanism of the immune system that can be activated by invading pathogens. Proteases produced by pathogenic bacteria, such as SPATEs, have proteolytic activity and can cleave components of the complement system, promoting bacterial resistance to human serum. Considering these factors, the proteolytic activity of Pet and its role in evading the complement system were investigated. Proteolytic assays were performed by incubating purified components of the complement system with Pet and Pet S260I (a catalytic site mutant) proteins. Pet, but not Pet S260I, could cleave C3, C5 and C9 components, and also inhibited the natural formation of C9 polymers. Furthermore, a dose-dependent inhibition of ZnCl2-induced C9 polymerization in vitro was observed. E. coli DH5α survived incubation with human serum pre-treated with Pet. Therefore, Pet can potentially interfere with the alternative and the terminal pathways of the complement system. In addition, by cleaving C9, Pet may inhibit membrane attack complex (MAC) formation on the bacterial outer membrane. Thus, our data are suggestive of a role of Pet in resistance of E. coli to human serum.
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Affiliation(s)
| | | | - Miriam Dibo
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
| | - Jazmin Huerta-Cantillo
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Mexico City, Mexico
| | - Fernando Navarro-Garcia
- Department of Cell Biology, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (IPN), Mexico City, Mexico
| | | | - Waldir P. Elias
- Laboratório de Bacteriologia, Instituto Butantan, São Paulo, Brazil
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2
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Navneet S, Brandon C, Simpson K, Rohrer B. Exploring the Therapeutic Potential of Elastase Inhibition in Age-Related Macular Degeneration in Mouse and Human. Cells 2023; 12:cells12091308. [PMID: 37174708 PMCID: PMC10177483 DOI: 10.3390/cells12091308] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 04/20/2023] [Accepted: 04/26/2023] [Indexed: 05/15/2023] Open
Abstract
Abnormal turnover of the extracellular matrix (ECM) protein elastin has been linked to AMD pathology. Elastin is a critical component of Bruch's membrane (BrM), an ECM layer that separates the retinal pigment epithelium (RPE) from the underlying choriocapillaris. Reduced integrity of BrM's elastin layer corresponds to areas of choroidal neovascularization (CNV) in wet AMD. Serum levels of elastin-derived peptides and anti-elastin antibodies are significantly elevated in AMD patients along with the prevalence of polymorphisms of genes regulating elastin turnover. Despite these results indicating significant associations between abnormal elastin turnover and AMD, very little is known about its exact role in AMD pathogenesis. Here we report on results that suggest that elastase enzymes could play a direct role in the pathogenesis of AMD. We found significantly increased elastase activity in the retinas and RPE cells of AMD mouse models, and AMD patient-iPSC-derived RPE cells. A1AT, a protease inhibitor that inactivates elastase, reduced CNV lesion sizes in mouse models. A1AT completely inhibited elastase-induced VEGFA expression and secretion, and restored RPE monolayer integrity in ARPE-19 monolayers. A1AT also mitigated RPE thickening, an early AMD phenotype, in HTRA1 overexpressing mice, HTRA1 being a serine protease with elastase activity. Finally, in an exploratory study, examining archival records from large patient data sets, we identified an association between A1AT use, age and AMD risk. Our results suggest that repurposing A1AT may have therapeutic potential in modifying the progression to AMD.
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Affiliation(s)
- Soumya Navneet
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Carlene Brandon
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Kit Simpson
- Department of Healthcare Leadership and Management, Medical University of South Carolina, Charleston, SC 29425, USA
| | - Bärbel Rohrer
- Department of Ophthalmology, Medical University of South Carolina, Charleston, SC 29425, USA
- Department of Neurosciences, Medical University of South Carolina, Charleston, SC 29425, USA
- Ralph H. Johnson VA Medical Center, Division of Research, Charleston, SC 29425, USA
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3
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Peng M, Tabashsum Z, Patel P, Bernhardt C, Biswas C, Meng J, Biswas D. Prevention of enteric bacterial infections and modulation of gut microbiota with conjugated linoleic acids producing Lactobacillus in mice. Gut Microbes 2020; 11:433-452. [PMID: 31411526 PMCID: PMC7524329 DOI: 10.1080/19490976.2019.1638724] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Probiotics are recognized for outcompeting pathogenic bacteria by competitive receptor-mediated colonization and secretion of functional metabolites which are antimicrobial against certain microbes as well as improving host's gut health and immunity. Recently, we have constructed a bioactive Lactobacillus casei (LC) strain, LC+mcra , by inserting mcra (myosin cross-reactive antigen) gene, which stimulates the conversion of conjugated linoleic acids. In this study, we evaluated the modulation of gut microbiome and protective roles of LC+mcra against pathogenic Salmonella enterica serovar Typhimurium (ST) and enterohemorrhagic E. coli (EHEC) infections in BALB/cJ mice. We observed that LC+mcra colonized efficiently in mice gut intestine and competitively reduced the infection with ST and EHEC in various locations of small and large intestine, specifically cecum, jejunum, and ileum (p < 0.05). Positive modulation of the cecal microbiota, for example, higher relative abundances of Firmicutes, lower relative abundances of Proteobacteria, and increased bacterial species diversity/richness, was detected in ST-challenged mice pretreated with LC+mcra based on 16S metagenomic sequencing. Cytokine gene expression analysis indicated that mice pretreated with LC+mcra associated with attenuated bacterial pathogen-induced gut inflammation. Furthermore, mice fed daily with LC+mcra for one week could protect themselves from the impairments caused by enteric infections with ST or EHEC. These impairments include weight loss, negative hematological changes, intestinal histological alterations, and potential death. This in vivo study suggests that daily consumption of novel conjugated linoleic acids over-producing probiotic effectively improves intestinal microbiota composition and prevents/combats foodborne enteric bacterial infections with pathogenic Salmonella and diarrheagenic E. coli.
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Affiliation(s)
- Mengfei Peng
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA,Biological Sciences Program, University of Maryland, College Park, MD, USA
| | - Zajeba Tabashsum
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Puja Patel
- Biological Sciences Program, University of Maryland, College Park, MD, USA
| | - Cassandra Bernhardt
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
| | - Chitrine Biswas
- Biological Sciences Program, University of Maryland, College Park, MD, USA
| | - Jianghong Meng
- Center for Food Safety and Security Systems, University of Maryland, College Park, MD, USA,Department of Nutrition and Food Science, University of Maryland, College Park, MD, USA
| | - Debabrata Biswas
- Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA,Biological Sciences Program, University of Maryland, College Park, MD, USA,Center for Food Safety and Security Systems, University of Maryland, College Park, MD, USA,CONTACT Debabrata Biswas Department of Animal and Avian Sciences, University of Maryland, College Park, MD, USA
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4
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O'Brien ME, Fee L, Browne N, Carroll TP, Meleady P, Henry M, McQuillan K, Murphy MP, Logan M, McCarthy C, McElvaney OJ, Reeves EP, McElvaney NG. Activation of complement component 3 is associated with airways disease and pulmonary emphysema in alpha-1 antitrypsin deficiency. Thorax 2020; 75:321-330. [PMID: 31959730 PMCID: PMC7231451 DOI: 10.1136/thoraxjnl-2019-214076] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Revised: 11/22/2019] [Accepted: 12/31/2019] [Indexed: 02/07/2023]
Abstract
INTRODUCTION Alpha-1 antitrypsin (AAT) deficiency (AATD) is associated with early onset emphysema. The aim of this study was to investigate whether AAT binding to plasma constituents could regulate their activation, and in AATD, exploit this binding event to better understand the condition and uncover novel biomarkers of therapeutic efficacy. METHODS To isolate AAT linker proteins, plasma samples were separated by size exclusion chromatography, followed by co-immunoprecipitation. AAT binding proteins were identified by mass spectrometry. Complement turnover and activation was determined by ELISA measurement of C3, C3a and C3d levels in plasma of healthy controls (n=15), AATD (n=51), non-AATD patients with obstructive airway disease (n=10) and AATD patients post AAT augmentation therapy (n=5). RESULTS Direct binding of complement C3 to AAT was identified in vivo and in vitro. Compared with healthy controls, a breakdown product of C3, C3d, was increased in AATD (0.04 µg/mL vs 1.96 µg/mL, p=0.0002), with a significant correlation between radiographic pulmonary emphysema and plasma levels of C3d (R2=0.37, p=0.001). In vivo, AAT augmentation therapy significantly reduced plasma levels of C3d in comparison to patients not receiving AAT therapy (0.15 µg/mL vs 2.18 µg/mL, respectively, p=0.001). DISCUSSION Results highlight the immune-modulatory impact of AAT on the complement system, involving an important potential role for complement activation in disease pathogenesis in AATD. The association between plasma C3d levels and pulmonary disease severity, that decrease in response to AAT augmentation therapy, supports the exploration of C3d as a candidate biomarker of therapeutic efficacy in AATD.
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Affiliation(s)
- Michael E O'Brien
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Laura Fee
- Alpha-1 Foundation Ireland, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Niall Browne
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Tomás P Carroll
- Alpha-1 Foundation Ireland, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Paula Meleady
- National Institute for Cellular Biology, Dublin City University, Glasnevin, Dublin, Ireland
| | - Michael Henry
- National Institute for Cellular Biology, Dublin City University, Glasnevin, Dublin, Ireland
| | - Karen McQuillan
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Mark P Murphy
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Mark Logan
- Department of Radiology, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Cormac McCarthy
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Oliver J McElvaney
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Emer P Reeves
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Noel G McElvaney
- Irish Centre for Genetic Lung Disease, Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
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5
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Oscarsson J, Claesson R, Lindholm M, Höglund Åberg C, Johansson A. Tools of Aggregatibacter actinomycetemcomitans to Evade the Host Response. J Clin Med 2019; 8:E1079. [PMID: 31336649 PMCID: PMC6678183 DOI: 10.3390/jcm8071079] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 07/08/2019] [Accepted: 07/18/2019] [Indexed: 02/06/2023] Open
Abstract
Periodontitis is an infection-induced inflammatory disease that affects the tooth supporting tissues, i.e., bone and connective tissues. The initiation and progression of this disease depend on dysbiotic ecological changes in the oral microbiome, thereby affecting the severity of disease through multiple immune-inflammatory responses. Aggregatibacter actinomycetemcomitans is a facultative anaerobic Gram-negative bacterium associated with such cellular and molecular mechanisms associated with the pathogenesis of periodontitis. In the present review, we outline virulence mechanisms that help the bacterium to escape the host response. These properties include invasiveness, secretion of exotoxins, serum resistance, and release of outer membrane vesicles. Virulence properties of A. actinomycetemcomitans that can contribute to treatment resistance in the infected individuals and upon translocation to the circulation, also induce pathogenic mechanisms associated with several systemic diseases.
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Affiliation(s)
- Jan Oscarsson
- Department of Odontology, Oral Microbiology, Umeå University, S-90187 Umeå, Sweden
| | - Rolf Claesson
- Department of Odontology, Oral Microbiology, Umeå University, S-90187 Umeå, Sweden
| | - Mark Lindholm
- Department of Odontology, Oral Microbiology, Umeå University, S-90187 Umeå, Sweden
| | - Carola Höglund Åberg
- Department of Odontology, Molecular Periodontology, Umeå University, S-901 87 Umeå, Sweden
| | - Anders Johansson
- Department of Odontology, Molecular Periodontology, Umeå University, S-901 87 Umeå, Sweden.
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6
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Elvington M, Liszewski MK, Atkinson JP. Evolution of the complement system: from defense of the single cell to guardian of the intravascular space. Immunol Rev 2017; 274:9-15. [PMID: 27782327 DOI: 10.1111/imr.12474] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The complement system is an evolutionarily ancient component of immunity that revolves around the central component C3. With the recent description of intracellular C3 stores in many types of human cells, our view of the complement system has expanded. In this article, we hypothesize that a primitive version of C3 comprised the first element of the original complement system and initially functioned intracellularly and on the membrane of single-celled organisms. With increasing specialization and multicellularity, C3 evolved a secretory capacity that allowed it to play a protective role in the interstitial space. Upon development of a pumped circulatory system, C3 was synthesized in large amounts and secreted by the liver to protect the intravascular space. Recent discoveries of intracellular C3 activation, a C3-based recycling pathway and C3 being a driver and programmer of cell metabolism suggest that the complement system utilizes C3 to guard not only extracellular but also the intracellular environment. We predict that the major functions of C3 in all four locations (i.e. intracellular, membrane, interstitium and circulation) are similar: opsonization, membrane perturbation, triggering inflammation, and metabolic reprogramming.
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Affiliation(s)
- Michelle Elvington
- Department of Internal Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, MO, USA
| | - M Kathryn Liszewski
- Department of Internal Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, MO, USA
| | - John P Atkinson
- Department of Internal Medicine, Division of Rheumatology, Washington University School of Medicine, Saint Louis, MO, USA.
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7
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Jiang X, Nguyen TT, Tian W, Sung YK, Yuan K, Qian J, Rajadas J, Sallenave JM, Nickel NP, de Jesus Perez V, Rabinovitch M, Nicolls MR. Cyclosporine Does Not Prevent Microvascular Loss in Transplantation but Can Synergize With a Neutrophil Elastase Inhibitor, Elafin, to Maintain Graft Perfusion During Acute Rejection. Am J Transplant 2015; 15:1768-81. [PMID: 25727073 PMCID: PMC4474772 DOI: 10.1111/ajt.13189] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 12/10/2014] [Accepted: 12/26/2014] [Indexed: 01/25/2023]
Abstract
The loss of a functional microvascular bed in rejecting solid organ transplants is correlated with fibrotic remodeling and chronic rejection; in lung allografts, this pathology is predicted by bronchoalveolar fluid neutrophilia which suggests a role for polymorphonuclear cells in microcirculatory injury. In a mouse orthotopic tracheal transplant model, cyclosporine, which primarily inhibits T cells, failed as a monotherapy for preventing microvessel rejection and graft ischemia. To target neutrophil action that may be contributing to vascular injury, we examined the effect of a neutrophil elastase inhibitor, elafin, on the microvascular health of transplant tissue. We showed that elafin monotherapy prolonged microvascular perfusion and enhanced tissue oxygenation while diminishing the infiltration of neutrophils and macrophages and decreasing tissue deposition of complement C3 and the membrane attack complex, C5b-9. Elafin was also found to promote angiogenesis through activation of the extracellular signal-regulated kinase (ERK) signaling pathway but was insufficient as a single agent to completely prevent tissue ischemia during acute rejection episodes. However, when combined with cyclosporine, elafin effectively preserved airway microvascular perfusion and oxygenation. The therapeutic strategy of targeting neutrophil elastase activity alongside standard immunosuppression during acute rejection episodes may be an effective approach for preventing the development of irreversible fibrotic remodeling.
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Affiliation(s)
- Xinguo Jiang
- Veterans’ Affairs Palo Alto Health Care System, Medical Service, Palo Alto, CA,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
| | - Tom T. Nguyen
- Veterans’ Affairs Palo Alto Health Care System, Medical Service, Palo Alto, CA,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
| | - Wen Tian
- Veterans’ Affairs Palo Alto Health Care System, Medical Service, Palo Alto, CA,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
| | - Yon K. Sung
- Veterans’ Affairs Palo Alto Health Care System, Medical Service, Palo Alto, CA,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
| | - Ke Yuan
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
| | - Jin Qian
- Veterans’ Affairs Palo Alto Health Care System, Medical Service, Palo Alto, CA,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
| | | | - Jean-Michel Sallenave
- Unité de Défense Innée et Inflammation, Institut Pasteur, Paris, France,INSERM U884, Paris, France
| | - Nils P. Nickel
- Cardiovascular Institute and Department of Pediatrics, Stanford, CA
| | - Vinicio de Jesus Perez
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
| | | | - Mark R. Nicolls
- Veterans’ Affairs Palo Alto Health Care System, Medical Service, Palo Alto, CA,Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University School of Medicine, Stanford, CA
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8
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Yuan X, Shan M, You R, Frazier MV, Hong MJ, Wetsel RA, Drouin S, Seryshev A, MD LZS, Cornwell L, Rossen RD, Corry DB, Kheradmand F. Activation of C3a receptor is required in cigarette smoke-mediated emphysema. Mucosal Immunol 2015; 8:874-85. [PMID: 25465103 PMCID: PMC4454642 DOI: 10.1038/mi.2014.118] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 10/23/2014] [Indexed: 02/04/2023]
Abstract
Exposure to cigarette smoke can initiate sterile inflammatory responses in the lung and activate myeloid dendritic cells (mDCs) that induce differentiation of T helper type 1 (Th1) and Th17 cells in the emphysematous lungs. Consumption of complement proteins increases in acute inflammation, but the contribution of complement protein 3 (C3) to chronic cigarette smoke-induced immune responses in the lung is not clear. Here, we show that following chronic exposure to cigarette smoke, C3-deficient (C3(-/-)) mice develop less emphysema and have fewer CD11b(+)CD11c(+) mDCs infiltrating the lungs as compared with wild-type mice. Proteolytic cleavage of C3 by neutrophil elastase releases C3a, which in turn increases the expression of its receptor (C3aR) on lung mDCs. Mice deficient in the C3aR (C3ar(-/-)) partially phenocopy the attenuated responses to chronic smoke observed in C3(-/-) mice. Consistent with a role for C3 in emphysema, C3 and its active fragments are deposited on the lung tissue of smokers with emphysema, and smoke-exposed mice. Together, these findings suggest a critical role for C3a through autocrine/paracrine induction of C3aR in the pathogenesis of cigarette smoke-induced sterile inflammation and provide new therapeutic targets for the treatment of emphysema.
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Affiliation(s)
- Xiaoyi Yuan
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
| | - Ming Shan
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
| | - Ran You
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
| | - Michael V. Frazier
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
| | - Monica Jeongsoo Hong
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
| | - Rick A. Wetsel
- Brown Foundation Institute of Molecular Medicine-Research Center for Immunology and Autoimmune Diseases, The University of Texas Medical School at Houston, Houston TX 77030
| | - Scott Drouin
- Brown Foundation Institute of Molecular Medicine-Research Center for Immunology and Autoimmune Diseases, The University of Texas Medical School at Houston, Houston TX 77030
| | - Alexander Seryshev
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
| | - Li-zhen Song MD
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
| | | | - Roger D Rossen
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
- Pathology and Immunology, Baylor College of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
- Michael E DeBakey VA Center for Translational Research on Inflammatory Diseases, Houston TX 77030
| | - David B. Corry
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
- Pathology and Immunology, Baylor College of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
- Biology of Inflammation Center, Baylor College of Medicine, Houston TX 77030
- Michael E DeBakey VA Center for Translational Research on Inflammatory Diseases, Houston TX 77030
| | - Farrah Kheradmand
- Department of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
- Pathology and Immunology, Baylor College of Medicine, The University of Texas Medical School at Houston, Houston TX 77030
- Biology of Inflammation Center, Baylor College of Medicine, Houston TX 77030
- Michael E DeBakey VA Center for Translational Research on Inflammatory Diseases, Houston TX 77030
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9
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Abstract
Complement is traditionally known to be a system of serum proteins that provide protection against pathogens through direct cell lysis and the mobilization of innate and adaptive immunity. However, recent work indicates that the complement system has additional physiological roles beyond those in host defence. In this Opinion article, we describe the new modes and locations of complement activation that enable it to interact with other cell effector systems, such as growth factor receptors, inflammasomes and metabolic pathways. We propose that the location of complement activation dictates its function.
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