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Lu Y, Wang R, Jin H, Xie J, Gu Q, Yang X. A novel peptide derived from the mannose binding lectin inhibits LPS-activated TLR4/NF-κB signaling and suppresses ocular inflammation. Cell Biol Int 2023. [PMID: 37332141 DOI: 10.1002/cbin.12058] [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: 11/27/2022] [Revised: 02/27/2023] [Accepted: 05/31/2023] [Indexed: 06/20/2023]
Abstract
Uveitis is a major cause of vision impairment worldwide. Current treatments have limited effectiveness but severe complications. Mannose binding lectin (MBL) is an important protein of the innate immune system that binds to TLR4 and suppresses LPS-induced inflammatory cytokine secretion. MBL-mediated inhibition of inflammation via the TLR4 pathway and MBL-derived peptides might be a potential therapeutics. In this study, we designed a novel MBL-derived peptide, WP-17, targeting TLR4. Bioinformatics analysis was conducted for the sequence, structure and biological properties of WP-17. The binding of WP-17 to THP-1 cells was analyzed using flow cytometry. Signaling molecules were analyzed by western blotting, and activation of NF-κB was measured by immunofluorescence-histochemical analysis. Effects of WP-17 were studied in vitro using LPS-stimulated THP-1 cells and in vivo in endotoxin-induced uveitis (EIU). Our results showed that WP-17 could bind to TLR4 expressed on macrophages, thus downregulating the expression levels of MyD88, IRAK-4, and TRAF-6, and inhibiting the downstream NF-kB signaling pathway and LPS-induced expression of TNF-α and IL-6 in THP-1 cells. Moreover, in EIU rats, intravitreal pretreatment with WP-17 demonstrated significant inhibitory effects on ocular inflammation, attenuating the clinical and histopathological manifestations of uveitis, reducing protein leakage and cell infiltration into the aqueous humor, and suppressing TNF-α and IL-6 production in ocular tissues. In summary, our study provides the first evidence of a novel MBL-derived peptide that suppressed activation of the NF-кB pathway by targeting TLR4. The peptide effectively inhibited rat uveitis and may be a promising candidate for the management of ocular inflammatory diseases.
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Affiliation(s)
- Yi Lu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Engineering Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- Shanghai Key Clinical Specialty, Shanghai, China
- Shanghai Clinical Research Center for Eye Diseases, Shanghai, China
| | - Ruonan Wang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Engineering Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- Shanghai Key Clinical Specialty, Shanghai, China
- Shanghai Clinical Research Center for Eye Diseases, Shanghai, China
| | - Huiyi Jin
- Department of Ophthalmology, Shanghai General Hospital, Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Engineering Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- Shanghai Key Clinical Specialty, Shanghai, China
- Shanghai Clinical Research Center for Eye Diseases, Shanghai, China
| | - Jiamin Xie
- Department of Ophthalmology, Shanghai General Hospital, Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Engineering Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- Shanghai Key Clinical Specialty, Shanghai, China
- Shanghai Clinical Research Center for Eye Diseases, Shanghai, China
| | - Qing Gu
- Department of Ophthalmology, Shanghai General Hospital, Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Engineering Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- Shanghai Key Clinical Specialty, Shanghai, China
- Shanghai Clinical Research Center for Eye Diseases, Shanghai, China
| | - Xiaolu Yang
- Department of Ophthalmology, Shanghai General Hospital, Shanghai JiaoTong University, Shanghai, China
- Shanghai Key Laboratory of Ocular Fundus Disease, Shanghai, China
- Shanghai Engineering Center for Visual Science and Photomedicine, Shanghai, China
- National Clinical Research Center for Eye Diseases, Shanghai, China
- Shanghai Engineering Center of Precise Diagnosis and Treatment of Eye Diseases, Shanghai, China
- Shanghai Key Clinical Specialty, Shanghai, China
- Shanghai Clinical Research Center for Eye Diseases, Shanghai, China
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2
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Yang J, Yang K, Wang K, Zhou D, Zhou J, Du X, Liu S, Cheng Z. Serum amyloid A regulates TLR2/4-mediated IFN-β signaling pathway against Marek's disease virus. Virus Res 2023; 326:199044. [PMID: 36652973 DOI: 10.1016/j.virusres.2023.199044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 01/09/2023] [Accepted: 01/13/2023] [Indexed: 01/16/2023]
Abstract
Serum amyloid A (SAA), an acute response phase protein (APP), is crucial for the innate immune response during pathogenic microorganisms' invasion. Marek's disease virus (MDV) is a highly oncogenic alphaherpesvirus that activates multiple innate immune molecules, including SAA, in the host during infection. However, the pathway through which SAA participates in MDV-induced host innate immunity remains unknown. The present study aimed to elucidate the pathway through which SAA exerts its anti-MDV function. We observed that MDV infection in vivo and in vitro significantly elevated SAA expression. Furthermore, through SAA overexpression and knockdown experiments, we demonstrated that SAA could inhibit MDV replication. Subsequently, we found that SAA activated Toll-Like Receptor 2/4 (TLR2/4) -mediated Interferon Beta (IFN-β) promoter activity and IFN regulatory factor 7 (IRF7) promoter activity. During MDV infection, SAA enhanced TLR2/4-mediated IFN-β signal transduction and messenger RNAs (mRNAs) expression of type I IFN (IFN-I) and interferon-stimulated genes (ISGs). Finally, TLR2/4 inhibitor OxPAPC inhibits the anti-MDV activity of SAA. These results demonstrated that SAA inhibits MDV replication and enhancing TLR2/4-mediated IFN-β signal transduction to promote IFNs and ISGs expression. This finding is the first to demonstrate the signaling pathway by which SAA exerts its anti-MDV function. It also provides new insights into the control of oncogenic herpesviruses from the perspective of acute response phase proteins.
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Affiliation(s)
- Jianhao Yang
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China
| | - Kunmei Yang
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China
| | - Kang Wang
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China
| | - Defang Zhou
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China
| | - Jing Zhou
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China
| | - Xusheng Du
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China
| | - Shenglong Liu
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China
| | - Ziqiang Cheng
- College of Veterinary Medicine, Shandong Agricultural University, 61 Daizong Street, Taian 271018, China.
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3
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Innate-Immunity Genes in Obesity. J Pers Med 2021; 11:jpm11111201. [PMID: 34834553 PMCID: PMC8623883 DOI: 10.3390/jpm11111201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 01/07/2023] Open
Abstract
The main functions of adipose tissue are thought to be storage and mobilization of the body’s energy reserves, active and passive thermoregulation, participation in the spatial organization of internal organs, protection of the body from lipotoxicity, and ectopic lipid deposition. After the discovery of adipokines, the endocrine function was added to the above list, and after the identification of crosstalk between adipocytes and immune cells, an immune function was suggested. Nonetheless, it turned out that the mechanisms underlying mutual regulatory relations of adipocytes, preadipocytes, immune cells, and their microenvironment are complex and redundant at many levels. One possible way to elucidate the picture of adipose-tissue regulation is to determine genetic variants correlating with obesity. In this review, we examine various aspects of adipose-tissue involvement in innate immune responses as well as variants of immune-response genes associated with obesity.
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Wang T, Li K, Xiao S, Xia Y. A Plausible Role for Collectins in Skin Immune Homeostasis. Front Immunol 2021; 12:594858. [PMID: 33790889 PMCID: PMC8006919 DOI: 10.3389/fimmu.2021.594858] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2020] [Accepted: 02/25/2021] [Indexed: 12/13/2022] Open
Abstract
The skin is a complex organ that faces the external environment and participates in the innate immune system. Skin immune homeostasis is necessary to defend against external microorganisms and to recover from stress to the skin. This homeostasis depends on interactions among a variety of cells, cytokines, and the complement system. Collectins belong to the lectin pathway of the complement system, and have various roles in innate immune responses. Mannose-binding lectin (MBL), collectin kidney 1, and liver (CL-K1, CL-L1) activate the lectin pathway, while all have multiple functions, including recognition of pathogens, opsonization of phagocytosis, and modulation of cytokine-mediated inflammatory responses. Certain collectins are localized in the skin, and their expressions change during skin diseases. In this review, we summarize important advances in our understanding of how MBL, surfactant proteins A and D, CL-L1, and CL-K1 function in skin immune homeostasis. Based on the potential roles of collectins in skin diseases, we suggest therapeutic strategies for skin diseases through the targeting of collectins and relevant regulators.
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Affiliation(s)
- Tian Wang
- Department of Dermatology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Ke Li
- Core Research Laboratory, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Shengxiang Xiao
- Department of Dermatology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
| | - Yumin Xia
- Department of Dermatology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, China
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Zheng DJ, Abou Taka M, Heit B. Role of Apoptotic Cell Clearance in Pneumonia and Inflammatory Lung Disease. Pathogens 2021; 10:134. [PMID: 33572846 PMCID: PMC7912081 DOI: 10.3390/pathogens10020134] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Revised: 01/25/2021] [Accepted: 01/26/2021] [Indexed: 02/07/2023] Open
Abstract
Pneumonia and inflammatory diseases of the pulmonary system such as chronic obstructive pulmonary disease and asthma continue to cause significant morbidity and mortality globally. While the etiology of these diseases is highly different, they share a number of similarities in the underlying inflammatory processes driving disease pathology. Multiple recent studies have identified failures in efferocytosis-the phagocytic clearance of apoptotic cells-as a common driver of inflammation and tissue destruction in these diseases. Effective efferocytosis has been shown to be important for resolving inflammatory diseases of the lung and the subsequent restoration of normal lung function, while many pneumonia-causing pathogens manipulate the efferocytic system to enhance their growth and avoid immunity. Moreover, some treatments used to manage these patients, such as inhaled corticosteroids for chronic obstructive pulmonary disease and the prevalent use of statins for cardiovascular disease, have been found to beneficially alter efferocytic activity in these patients. In this review, we provide an overview of the efferocytic process and its role in the pathophysiology and resolution of pneumonia and other inflammatory diseases of the lungs, and discuss the utility of existing and emerging therapies for modulating efferocytosis as potential treatments for these diseases.
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Affiliation(s)
- David Jiao Zheng
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, ON N0M 2N0, Canada; (D.J.Z.); (M.A.T.)
| | - Maria Abou Taka
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, ON N0M 2N0, Canada; (D.J.Z.); (M.A.T.)
| | - Bryan Heit
- Department of Microbiology and Immunology, Center for Human Immunology, The University of Western Ontario, London, ON N0M 2N0, Canada; (D.J.Z.); (M.A.T.)
- Robarts Research Institute, London, ON N6A 5K8, Canada
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Holers VM, Borodovsky A, Scheinman RI, Ho N, Ramirez JR, Dobó J, Gál P, Lindenberger J, Hansen AG, Desai D, Pihl R, Thiel S, Banda NK. Key Components of the Complement Lectin Pathway Are Not Only Required for the Development of Inflammatory Arthritis but Also Regulate the Transcription of Factor D. Front Immunol 2020; 11:201. [PMID: 32153567 PMCID: PMC7046807 DOI: 10.3389/fimmu.2020.00201] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 01/27/2020] [Indexed: 12/12/2022] Open
Abstract
The complement system plays an important role in the pathogenesis of rheumatoid arthritis (RA). Besides driving lectin pathway (LP) activation, the mannan-binding lectin (MBL)-associated serine proteases (MASPs) also play a key role in regulating the alternative pathway (AP). We evaluated the effects of N-acetylgalactosamine (GalNAc)-conjugated MASP-1 and MASP-2 duplexes in vitro and in mice with and without arthritis to examine whether knockdown of MASP-1 and MASP-2 expression affects the development of arthritis. GalNAc-siRNAs for MASP-1 and MASP-2 demonstrated robust silencing of MASP-1 or MASP-2 at pM concentrations in vitro. To evaluate the impact of silencing in arthritic mice, we used the collagen antibody-induced arthritis (CAIA) mouse model of RA. Mice were injected a 10 mg/kg dose of GalNAc-siRNAs 3x s.q. prior to the induction of CAIA. Liver gene expression was examined using qRT-PCR, and protein levels were confirmed in the circulation by sandwich immunoassays and Western blot. At day 10, CAIA mice separately treated with MASP-1 and MASP-2 duplexes had a specific reduction in expression of liver MASP-1 (70–95%, p < 0.05) and MASP-2 (90%, p < 0.05) mRNA, respectively. MASP-1-siRNA treatment resulted in a 95% reduction in levels of MASP-1 protein in circulation with no effect on MASP-2 levels and clinical disease activity (CDA). In mice injected with MASP-2 duplex, there was a significant (p < 0.05) 90% decrease in ex vivo C4b deposition on mannan, with nearly complete elimination of MASP-2 in the circulation. MASP-2 silencing initially significantly decreased CDA by 60% but subsequently changed to a 40% decrease vs. control. Unexpectedly, GalNAc-siRNA-mediated knockdown of MASP-1 and MASP-2 revealed a marked effect of these proteins on the transcription of FD under normal physiological conditions, whereas LPS-induced inflammatory conditions reversed this effect on FD levels. LPS is recognized by Toll-like receptor 4 (TLR4), we found MBL not only binds to TLR4 an interaction with a Kd of 907 nM but also upregulated FD expression in differentiated adipocytes. We show that MASP-2 knockdown impairs the development of RA and that the interrelationship between proteins of the LP and the AP may extend to the transcriptional modulation of the FD gene.
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Affiliation(s)
- V Michael Holers
- Division of Rheumatology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | | | - Robert I Scheinman
- Skaggs School of Pharmacy, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Nhu Ho
- Division of Rheumatology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - Joseline Ramos Ramirez
- Division of Rheumatology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
| | - József Dobó
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Péter Gál
- Research Centre for Natural Sciences, Institute of Enzymology, Budapest, Hungary
| | - Jared Lindenberger
- Department of Biochemistry and Molecular Genetics, University of Colorado Denver Anschutz Medical Campus, Aurora, CO, United States
| | - Annette G Hansen
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Dhruv Desai
- Alnylam Pharmaceutical Inc., Boston, MA, United States
| | - Rasmus Pihl
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Steffen Thiel
- Department of Biomedicine, University of Aarhus, Aarhus, Denmark
| | - Nirmal K Banda
- Division of Rheumatology, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States
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Mannan-Binding Lectin Suppresses Peptidoglycan-Induced TLR2 Activation and Inflammatory Responses. Mediators Inflamm 2019; 2019:1349784. [PMID: 30728747 PMCID: PMC6343158 DOI: 10.1155/2019/1349784] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2018] [Accepted: 11/01/2018] [Indexed: 01/08/2023] Open
Abstract
Peptidoglycan (PGN), as the major components of the bacterial cell wall, is known to cause excessive proinflammatory cytokine production. Toll-like receptor 2 (TLR2) is abundantly expressed on immune cells and has been shown to be involved in PGN-induced signaling. Although more and more evidences have indicated that PGN is recognized by TLR2, the role of TLR2 PGN recognition is controversial. Mannan-binding lectin (MBL), a plasma C-type lectin, plays a key role in innate immunity. More and more evidences show that MBL could suppress the amplification of inflammatory signals. Whether MBL can alter PGN-elicited cellular responses through TLR2 in macrophages is still unknown, and possible mechanism underlying it should be investigated. In this study, we found that MBL significantly attenuated PGN-induced inflammatory cytokine production, including TNF-α and IL-6, in PMA-stimulated THP-1 cells at both mRNA and protein levels. The expression of TLR2 was strongly induced by PGN stimulation. Furthermore, the administration of TLR2-neutralized antibody effectively suppressed PGN-induced TNF-α and IL-6 expression. These results supplied the evidence that PGN from Saccharomyces cerevisiae could be recognized by TLR2. In addition, we also found that MBL decreased PGN-induced TLR2 expression and suppressed TLR2-mediated downstream signaling, including the phosphorylation of IκBα, nuclear translocation of NF-κBp65, and phosphorylation of MAPK p38 and ERK1/2. Administration of MBL alone did not have an effect on the expression of TLR2. Finally, our data showed that PGN-mediated immune responses were more severely suppressed by preincubation with MBL and indicated that MBL can combine with both TLR2 and PGN to block the inflammation cytokine expression induced by PGN. All these data suggest that MBL could downregulate inflammation by modulating PGN/TLR2 signaling pathways. This study supports an important role for MBL in immune regulation and signaling pathways involved in inflammatory responses.
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8
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Testicular expression of SP-A, SP-D and MBL-A is positively regulated by testosterone and modulated by lipopolysaccharide. Immunobiology 2016; 221:975-85. [DOI: 10.1016/j.imbio.2016.05.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2016] [Revised: 04/22/2016] [Accepted: 05/23/2016] [Indexed: 11/21/2022]
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9
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Dulay AT, Buhimschi CS, Zhao G, Oliver EA, Abdel-Razeq SS, Shook LL, Bahtiyar MO, Buhimschi IA. Amniotic Fluid Soluble Myeloid Differentiation-2 (sMD-2) as Regulator of Intra-amniotic Inflammation in Infection-induced Preterm Birth. Am J Reprod Immunol 2015; 73:507-21. [PMID: 25605324 DOI: 10.1111/aji.12362] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/02/2015] [Indexed: 01/02/2023] Open
Abstract
PROBLEM TLR4 mediates host responses to pathogens through a mechanism that involves protein myeloid differentiation-2 (MD-2) and its soluble form sMD-2. The role of sMD2 in intra-amniotic inflammation-induced preterm birth has not been previously explored. METHOD OF STUDY Human amniotic fluid (AF) sMD-2 was studied by Western blotting in 152 AF samples of patients who had an amniocentesis to rule-out infection (yes infection, n = 50; no infection, n = 50) or women with normal pregnancy outcome (second trimester genetic karyotyping, n = 26; third trimester lung maturity testing, n = 26). Histological localization and mRNA expression of MD2 in fetal membranes were studied by immunohistochemistry and RT-PCR. The ability of fetal membrane to release sMD-2 and inflammatory cytokines was studied in vitro. RESULTS Human AF contains three sMD-2 proteoforms whose levels of expression were lower at term. Intra-amniotic infection upregulated sMD-2. MD-2 mRNA and immunohistochemistry findings concurred. In vitro, LPS and monensin increased, while cycloheximide decreased sMD-2 production. Recombinant sMD-2 modulated TNF-α and IL-6 levels in a dose- and time-dependent fashion. CONCLUSION sMD2 proteoforms are constitutively present in human AF. The intensity of the intra-amniotic inflammatory response to bacteria or perhaps to other TLR4 ligands may be facilitated through synthesis and release of sMD2 by the amniochorion.
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Affiliation(s)
- Antonette T Dulay
- Department of Obstetrics & Gynecology, The Ohio State University College of Medicine, Columbus, OH, USA.,Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Catalin S Buhimschi
- Department of Obstetrics & Gynecology, The Ohio State University College of Medicine, Columbus, OH, USA.,Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
| | - Guomao Zhao
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Emily A Oliver
- Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA
| | - Sonya S Abdel-Razeq
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, USA
| | - Lydia L Shook
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, USA
| | - Mert O Bahtiyar
- Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT, USA
| | - Irina A Buhimschi
- Department of Obstetrics & Gynecology, The Ohio State University College of Medicine, Columbus, OH, USA.,Center for Perinatal Research, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.,Department of Pediatrics, The Ohio State University College of Medicine, Columbus, OH, USA
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Escudero-Pérez B, Volchkova VA, Dolnik O, Lawrence P, Volchkov VE. Shed GP of Ebola virus triggers immune activation and increased vascular permeability. PLoS Pathog 2014; 10:e1004509. [PMID: 25412102 PMCID: PMC4239094 DOI: 10.1371/journal.ppat.1004509] [Citation(s) in RCA: 128] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/09/2014] [Indexed: 11/19/2022] Open
Abstract
During Ebola virus (EBOV) infection a significant amount of surface glycoprotein GP is shed from infected cells in a soluble form due to cleavage by cellular metalloprotease TACE. Shed GP and non-structural secreted glycoprotein sGP, both expressed from the same GP gene, have been detected in the blood of human patients and experimentally infected animals. In this study we demonstrate that shed GP could play a particular role during EBOV infection. In effect it binds and activates non-infected dendritic cells and macrophages inducing the secretion of pro- and anti-inflammatory cytokines (TNFα, IL1β, IL6, IL8, IL12p40, and IL1-RA, IL10). Activation of these cells by shed GP correlates with the increase in surface expression of co-stimulatory molecules CD40, CD80, CD83 and CD86. Contrary to shed GP, secreted sGP activates neither DC nor macrophages while it could bind DCs. In this study, we show that shed GP activity is likely mediated through cellular toll-like receptor 4 (TLR4) and is dependent on GP glycosylation. Treatment of cells with anti-TLR4 antibody completely abolishes shed GP-induced activation of cells. We also demonstrate that shed GP activity is negated upon addition of mannose-binding sera lectin MBL, a molecule known to interact with sugar arrays present on the surface of different microorganisms. Furthermore, we highlight the ability of shed GP to affect endothelial cell function both directly and indirectly, demonstrating the interplay between shed GP, systemic cytokine release and increased vascular permeability. In conclusion, shed GP released from virus-infected cells could activate non-infected DCs and macrophages causing the massive release of pro- and anti-inflammatory cytokines and effect vascular permeability. These activities could be at the heart of the excessive and dysregulated inflammatory host reactions to infection and thus contribute to high virus pathogenicity. Ebola virus, a member of the Filoviridae family, causes lethal hemorrhagic fever in man and primates, displaying up to 90% mortality rates. Viral infection is typified by an excessive systemic inflammatory response resembling septic shock. It also damages endothelial cells and creates difficulty in coagulation, ultimately leading to haemorrhaging, organ failure and death. A unique feature of EBOV is that following infection high amounts of truncated surface GP, named shed GP, are released from infected cells and are detected in the blood of patients and experimentally infected animals. However the role of shed GP in virus replication and pathogenicity is not yet clearly defined. Here we show that shed GP released from virus-infected cells binds and activates non-infected DCs and macrophages causing the massive release of pro- and anti-inflammatory cytokines and also affects vascular permeability. These activities could be at the heart of the excessive and dysregulated inflammatory host reactions to infection and thus contribute to high virus pathogenicity.
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Affiliation(s)
- Beatriz Escudero-Pérez
- Molecular Basis of Viral Pathogenicity, CIRI, INSERM U1111- CNRS UMR5308, Université de Lyon, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Valentina A. Volchkova
- Molecular Basis of Viral Pathogenicity, CIRI, INSERM U1111- CNRS UMR5308, Université de Lyon, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Olga Dolnik
- Molecular Basis of Viral Pathogenicity, CIRI, INSERM U1111- CNRS UMR5308, Université de Lyon, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Philip Lawrence
- Molecular Basis of Viral Pathogenicity, CIRI, INSERM U1111- CNRS UMR5308, Université de Lyon, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France
| | - Viktor E. Volchkov
- Molecular Basis of Viral Pathogenicity, CIRI, INSERM U1111- CNRS UMR5308, Université de Lyon, Université Claude Bernard Lyon 1, Ecole Normale Supérieure de Lyon, Lyon, France
- * E-mail:
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11
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Tran HB, Ahern J, Hodge G, Holt P, Dean MM, Reynolds PN, Hodge S. Oxidative stress decreases functional airway mannose binding lectin in COPD. PLoS One 2014; 9:e98571. [PMID: 24901869 PMCID: PMC4047017 DOI: 10.1371/journal.pone.0098571] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2014] [Accepted: 05/05/2014] [Indexed: 01/22/2023] Open
Abstract
We have previously established that a defect in the ability of alveolar macrophages (AM) to phagocytose apoptotic cells (efferocytosis) and pathogens is a potential therapeutic target in COPD. We further showed that levels of mannose binding lectin (MBL; required for effective macrophage phagocytic function) were reduced in the airways but not circulation of COPD patients. We hypothesized that increased oxidative stress in the airway could be a cause for such disturbances. We therefore studied the effects of oxidation on the structure of the MBL molecule and its functional interactions with macrophages. Oligomeric structure of plasma derived MBL (pdMBL) before and after oxidation (oxMBL) with 2,2′-azobis(2-methylpropionamidine)dihydrochroride (AAPH) was investigated by blue native PAGE. Macrophage function in the presence of pd/oxMBL was assessed by measuring efferocytosis, phagocytosis of non-typeable Haemophilus influenzae (NTHi) and expression of macrophage scavenger receptors. Oxidation disrupted higher order MBL oligomers. This was associated with changed macrophage function evident by a significantly reduced capacity to phagocytose apoptotic cells and NTHi in the presence of oxMBL vs pdMBL (eg, NTHi by 55.9 and 27.0% respectively). Interestingly, oxidation of MBL significantly reduced macrophage phagocytic ability to below control levels. Flow cytometry and immunofluorescence revealed a significant increase in expression of macrophage scavenger receptor (SRA1) in the presence of pdMBL that was abrogated in the presence of oxMBL. We show the pulmonary macrophage dysfunction in COPD may at least partially result from an oxidative stress-induced effect on MBL, and identify a further potential therapeutic strategy for this debilitating disease.
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Affiliation(s)
- Hai B. Tran
- Lung Research, Hanson Institute and Department Thoracic Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- * E-mail:
| | - Jessica Ahern
- Lung Research, Hanson Institute and Department Thoracic Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Greg Hodge
- Lung Research, Hanson Institute and Department Thoracic Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Phillip Holt
- Lung Research, Hanson Institute and Department Thoracic Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
| | - Melinda M. Dean
- Research and Development, Australian Red Cross Blood Service, Brisbane, Queensland, Australia
| | - Paul N. Reynolds
- Lung Research, Hanson Institute and Department Thoracic Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia
| | - Sandra Hodge
- Lung Research, Hanson Institute and Department Thoracic Medicine, Royal Adelaide Hospital, Adelaide, South Australia, Australia
- Department of Medicine, University of Adelaide, Adelaide, South Australia, Australia
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Liu H, Zhou J, Ma D, Lu X, Ming S, Shan G, Zhang X, Hou J, Chen Z, Zuo D. Mannan binding lectin attenuates double-stranded RNA-mediated TLR3 activation and innate immunity. FEBS Lett 2014; 588:866-72. [PMID: 24530528 DOI: 10.1016/j.febslet.2014.01.064] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2013] [Accepted: 01/21/2014] [Indexed: 01/04/2023]
Abstract
Mannan binding lectin (MBL) functions as a pattern recognition molecule (PRM) which is able to initiate complement activation. Here, we characterize a previously unrecognized attribute of MBL as a double-stranded RNA (dsRNA) binding protein capable of modifying Toll like receptor 3 (TLR3) activation. MBL interacts with poly(I:C) and suppresses poly(I:C)-induced activation of TLR3 pathways and subsequent cytokine production. In addition, MBL binds to TLR3 directly. Surprisingly, disrupting the interaction between MBL and complement receptor 1 (CR1) or restraining the traffic of MBL to phagosome reversed the MBL limited TLR3 activation. We demonstrate the importance of MBL guided ligands intracellular localization, emphasizing the significance of understanding the dynamics of TLR agonists complexed with MBL or other PRMs inside the cell in immune defense.
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Affiliation(s)
- Hongzhi Liu
- Department of Immunology, Southern Medical University, Guangzhou 510515, China
| | - Jia Zhou
- Department of Immunology, Southern Medical University, Guangzhou 510515, China
| | - Di Ma
- Department of Immunology, Southern Medical University, Guangzhou 510515, China
| | - Xiao Lu
- Department of Immunology, Southern Medical University, Guangzhou 510515, China
| | - Siqi Ming
- Department of Immunology, Southern Medical University, Guangzhou 510515, China
| | - Guiqiu Shan
- Department of Immunology, Southern Medical University, Guangzhou 510515, China; Guangzhou General Hospital of Guangzhou Military Command, Guangzhou 510010, China
| | - Xiaoyong Zhang
- Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Jinlin Hou
- Department of Infectious Diseases and Hepatology Unit, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China
| | - Zhengliang Chen
- Department of Immunology, Southern Medical University, Guangzhou 510515, China.
| | - Daming Zuo
- Department of Immunology, Southern Medical University, Guangzhou 510515, China; Collaborative Innovation Center for Diagnosis and Treatment of Infectious Diseases, Zhejiang University, Hangzhou 310003, China.
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Wang M, Wang F, Yang J, Zhao D, Wang H, Shao F, Wang W, Sun R, Ling M, Zhai J, Song S. Mannan-binding lectin inhibits Candida albicans-induced cellular responses in PMA-activated THP-1 cells through Toll-like receptor 2 and Toll-like receptor 4. PLoS One 2013; 8:e83517. [PMID: 24391778 PMCID: PMC3877063 DOI: 10.1371/journal.pone.0083517] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Accepted: 11/04/2013] [Indexed: 11/29/2022] Open
Abstract
Background Candida albicans (C. albicans), the most common human fungal pathogen, can cause fatal systemic infections under certain circumstances. Mannan-binding lectin (MBL),a member of the collectin family in the C-type lectin superfamily, is an important serum component associated with innate immunity. Toll-like receptors (TLRs) are expressed extensively, and have been shown to be involved in C. albicans-induced cellular responses. We first examined whether MBL modulated heat-killed (HK) C. albicans-induced cellular responses in phorbol 12-myristate 13-acetate (PMA)-activated human THP-1 macrophages. We then investigated the possible mechanisms of its inhibitory effect. Methodology/Principal Finding Enzyme-linked immunosorbent assay (ELISA) and reverse transcriptasepolymerase chain reaction (RT-PCR) analysis showed that MBL at higher concentrations (10–20 µg/ml) significantly attenuated C. albicans-induced chemokine (e.g., IL-8) and proinflammatory cytokine (e.g., TNF-α) production from PMA-activated THP-1 cells at both protein and mRNA levels. Electrophoretic mobility shift assay (EMSA) and Western blot (WB) analysis showed that MBL could inhibit C. albicans-induced nuclear factor-κB (NF-κB) DNA binding and its translocation in PMA-activated THP-1 cells. MBL could directly bind to PMA-activated THP-1 cells in the presence of Ca2+, and this binding decreased TLR2 and TLR4 expressions in C. albicans-induced THP-1 macrophages. Furthermore, the binding could be partially inhibited by both anti-TLR2 monoclonal antibody (clone TL2.1) and anti-TLR4 monoclonal antibody (clone HTA125). In addition, co-immunoprecipitation experiments and microtiter wells assay showed that MBL could directly bind to the recombinant soluble form of extracellular TLR2 domain (sTLR2) and sTLR4. Conclusions/Significance Our study demonstrates that MBL can affect proinflammatory cytokine and chemokine expressions by modifying C. albicans-/TLR-signaling pathways. This study supports an important role for MBL on the regulation of C. albicans-induced cellular responses.
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Affiliation(s)
- Mingyong Wang
- Department of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
- * E-mail:
| | - Fanping Wang
- Department of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Jianbin Yang
- Department of Clinical Laboratory, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Dongfang Zhao
- Department of Clinical Laboratory, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Hongpo Wang
- Department of Clinical Laboratory, The First Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Feng Shao
- Department of Clinical Laboratory, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
| | - Wenjun Wang
- Cancer Research Institute, Southern Medical University, Guangzhou, China
| | - Ruili Sun
- Department of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Mingzhi Ling
- Department of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Jingjing Zhai
- Department of Laboratory Medicine, Xinxiang Medical University, Xinxiang, China
| | - Shijun Song
- Department of Clinical Laboratory, The Third Affiliated Hospital of Xinxiang Medical University, Xinxiang, China
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Association between mannose-binding lectin gene polymorphisms and necrotizing enterocolitis in preterm infants. J Pediatr Gastroenterol Nutr 2012; 55:160-5. [PMID: 22331020 DOI: 10.1097/mpg.0b013e31824e5f7a] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVES The aim of the present study was to evaluate whether polymorphisms of the mannose-binding lectin (MBL-2) gene and MBL serum levels on admission to neonatal intensive care unit are associated with necrotizing enterocolitis (NEC) in preterm infants and to verify MBL expression in NEC bowels. METHODS In this retrospective cohort study, 107 neonates (41 with NEC and 66 controls) were included. MBL-2 genotyping for the promoter polymorphism -221 and for the exon 1 variant alleles at codons 52, 54, and 57 was performed. MBL levels were determined by enzyme-linked immunosorbent assay in 55 infants. Immunohistochemical staining for MBL expression was performed on bowel specimens. The main study outcome was severe NEC (Bell stages II/III). RESULTS The -221 Y allele and the MBL-2 YY genotype were more frequent in neonates with severe NEC than in controls (P = 0.04 and P = 0.004, respectively). In the multivariate analysis, the MBL-2 YA/YA genotype was associated with NEC (odds ratio = 3.03, 95% confidence interval 1.13%-8.13%, P = 0.024). Neonates with NEC had MBL level on admission >400 ng/mL more frequently than controls (P = 0.043). Among neonates with severe NEC, the deceased neonates were carriers of high or intermediate producing MBL-2 genotypes (P = 0.035). Finally, MBL was highly expressed in intestinal tissue from infants with NEC. CONCLUSIONS MBL-2 genotypes associated with high MBL serum levels represent a risk factor for NEC. This finding, together with the MBL expression in bowel tissue, supports a role for MBL in the pathogenesis of NEC.
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Wang M, Chen Y, Zhang Y, Zhang L, Lu X, Chen Z. Mannan-binding lectin directly interacts with Toll-like receptor 4 and suppresses lipopolysaccharide-induced inflammatory cytokine secretion from THP-1 cells. Cell Mol Immunol 2011; 8:265-75. [PMID: 21383675 DOI: 10.1038/cmi.2011.1] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mannan-binding lectin (MBL) plays a key role in the lectin pathway of complement activation and can influence cytokine expression. Toll-like receptor 4 (TLR4) is expressed extensively and has been demonstrated to be involved in lipopolysaccharide (LPS)-induced signaling. We first sought to determine whether MBL exposure could modulate LPS-induced inflammatory cytokine secretion and nuclear factor-κB (NF-κB) activity by using the monocytoid cell line THP-1. We then investigated the possible mechanisms underlying any observed regulatory effect. Using ELISA and reverse transcriptase polymerase chain reaction (RT-PCR) analysis, we found that at both the protein and mRNA levels, treatment with MBL suppresses LPS-induced tumor-necrosis factor (TNF)-α and IL-12 production in THP-1 cells. An electrophoretic mobility shift assay and western blot analysis revealed that MBL treatment can inhibit LPS-induced NF-κB DNA binding and translocation in THP-1 cells. While the binding of MBL to THP-1 cells was evident at physiological calcium concentrations, this binding occurred optimally in response to supraphysiological calcium concentrations. This binding can be partly inhibited by treatment with either a soluble form of recombinant TLR4 extracellular domain or anti-TLR4 monoclonal antibody (HTA125). Activation of THP-1 cells by LPS treatment resulted in increased MBL binding. We also observed that MBL could directly bind to the extracellular domain of TLR4 in a dose-dependent manner, and this interaction could attenuate the binding of LPS to cell surfaces. Taken together, these data suggest that MBL may affect cytokine expression through modulation of LPS-/TLR-signaling pathways. These findings suggest that MBL may play an important role in both immune regulation and the signaling pathways involved in cytokine networks.
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Affiliation(s)
- Mingyong Wang
- Department of Immunology, Southern Medical University, Guangzhou, China
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Wang M, Zhang Y, Chen Y, Zhang L, Lu X, Chen Z. Mannan-binding lectin regulates dendritic cell maturation and cytokine production induced by lipopolysaccharide. BMC Immunol 2011; 12:1. [PMID: 21194488 PMCID: PMC3022617 DOI: 10.1186/1471-2172-12-1] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Accepted: 01/01/2011] [Indexed: 12/04/2022] Open
Abstract
Background Mannan-binding lectin (MBL) is a pattern-recognition molecule present in serum, which is involved in the innate immune defense by activating complement and promoting opsonophagocytosis. Dendritic cells (DCs) are professional antigen presenting cells (APCs) that are crucial for the initiation of adaptive immunity. Lipopolysaccharide (LPS) has been shown to be a strong activator of the inflammatory response and immune regulation. We first examined whether MBL modulated LPS-induced cellular responses, then investigated possible mechanisms of its inhibitory effect. Results MBL at higher concentrations (10-20 μg/ml) significantly attenuated LPS-induced maturation of monocyte-derived DCs (MDCs) and production of proinflammatory cytokines (e.g., IL-12 and TNF-α), and inhibited their ability to activate allogeneic T lymphocytes. It bound to immature MDCs at physiological calcium concentrations, and was optimal at supraphysiological calcium concentrations. MBL also bound directly to immature MDCs and attenuated the binding of LPS to the cell surfaces, resulting in decreased LPS-induced nuclear factor-κB (NF-κB) activity in these cells. Conclusion All these data suggest that MBL could affect the functions of DCs by modifying LPS-induced cellular responses. This study supports an important role for MBL in the regulation of adaptive immune responses and inflammatory responses.
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Affiliation(s)
- Mingyong Wang
- Department of Immunology, Southern Medical University, Guangzhou, 510515, PR China
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MacDonald SL, Downing I, Atkinson AP, Gallagher RC, Turner ML, Kilpatrick DC. Dendritic cells previously exposed to mannan-binding lectin enhance cytokine production in allogeneic mononuclear cell cultures. Hum Immunol 2010; 71:1077-83. [DOI: 10.1016/j.humimm.2010.07.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 07/02/2010] [Accepted: 07/12/2010] [Indexed: 10/19/2022]
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Löfgren J, Marttila R, Renko M, Rämet M, Hallman M. Toll-like receptor 4 Asp299Gly polymorphism in respiratory syncytial virus epidemics. Pediatr Pulmonol 2010; 45:687-92. [PMID: 20575099 DOI: 10.1002/ppul.21248] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The respiratory syncytial virus (RSV) antigen serves as ligand for Toll-like receptor (TLR) 4 that is a transmembrane signaling receptor in macrophages and dendritic cells. According to current evidence single nucleotide polymorphism involving amino acid 299 influences the susceptibility to severe RSV infections. The Asp299Gly allele has been shown to influence the TLR4-mediated signaling causing conformational change in the extracellular domain that recognizes pathogen-associated molecular patterns. The aim was to study the association between the TLR4 Asp299Gly polymorphism and the susceptibility to severe RSV bronchiolitis in infants. Altogether 312 cases and 356 controls, selected on the basis place of residence, date of birth, gender, and gestation at birth, were studied. When adjusted for multiple dependent variables, no allele or genotype frequency difference was found between the cases and the controls. Post hoc analysis revealed that during the year 2000 epidemics, the Gly299Gly genotype associated with protection against severe RSV and during 2004 epidemics Gly299Gly genotype and 299Gly allele associated with severe RSV. To conclude, we could not confirm the association of the Gly299 allele with severe RSV. This is consistent with the evidence that the susceptibility to severe RSV infection is principally dependent on environmental and constitutional factors. We propose that the risk of severe RSV infection may additionally depend on the interaction between individual TLR4 genotype and the particular RSV group causing bronchiolitis.
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Affiliation(s)
- Johan Löfgren
- Department of Pediatrics, Oulu University Hospital, Oulu, Finland
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Abstract
The search for common host mechanisms that recognize human fungal pathogens as non-self has led to an increased interest in cell wall polysaccharides since they are absent from mammals and at least for some of them, common to all fungal species. Even though the receptors recognizing mannans and beta-1,3-glucans have been extensively studied to date, the epitope of the polysaccharide ligand is often not well defined. In addition, receptors recognizing other cell wall major components such as chitin, alpha-1,3-glucan or galactose polymers remain to be identified. Moreover, the fungal adhesins playing a role in adhesion to host have been only explored in yeasts. Eventhough progresses have been made in the last 10 years, a comprehensive understanding of the interactions between the host membrane receptors and the fungal cell wall components is still lacking.
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Affiliation(s)
- Jean-Paul Latgé
- Institut Pasteur, Unité des Aspergillus, 25 rue du Docteur Roux, 75724 Paris cedex 15, France.
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