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Wu Y, Du H, Zhu L, Zhao N, Zhang S, Cao Z, Zhou Y, Sun Y. Bactericidal permeability-increasing protein/LPS-binding protein (BPI/LBP) enhances resistance of golden pompano Trachinotus ovatus against bacterial infection. FISH & SHELLFISH IMMUNOLOGY 2022; 131:872-880. [PMID: 36347416 DOI: 10.1016/j.fsi.2022.10.065] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 10/28/2022] [Accepted: 10/30/2022] [Indexed: 06/16/2023]
Abstract
Antimicrobial peptides are crucial components of innate immunity against microbial invasions. As a kind of antimicrobial peptides, bactericidal permeability-increasing protein (BPI)/lipopolysaccharide-binding protein (LBP) play vital roles in defending the host against gram-negative bacteria. In the current study, a novel BPI/LBP from Trachinotus ovatus (TroBPI/LBP) was characterized. The full length of TroBPI/LBP cDNA sequence is 1434 bp, which contained 477 amino acids. Multiple amino acid alignments of TroBPI/LBP shows 34.07%-84.49% identity with other fish BPI/LBP. Similar to other BPI/LBP, TroBPI/LBP also possesses an N-terminal signal peptide, a BPI/LBP/CETP N-terminal domain, and a BPI/LBP/CETP C-terminal domain. In vitro, the recombinant protein of TroBPI/LBP showed effective bacterial depression activity and binding activity to gram-negative bacteria. In vivo, TroBPI/LBP was constitutively expressed in tested tissues, and the highest expression level was in liver. Following Vibrio alginolyticus stimulation, the mRNA expression of TroBPI/LBP was significantly upregulated in immune-related tissues, and peaked at 12 h post-infection, which confirmed that TroBPI/LBP was highly sensitive to V. alginolyticus stimuli. Furthermore, functional analyses showed that the overexpression of TroBPI/LBP could enhance the ability of fish to against V. alginolyticus infection, and the knockdown of TroBPI/LBP significantly diminished bacterial clearance capacity post-infection. Therefore, these results suggest that TroBPI/LBP may play an important role in host defense against bacterial infection.
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Affiliation(s)
- Ying Wu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Collaborative Innovation Center of Marine Science and Technology, College of Marine Science, Hainan University, Haikou, Hainan, 570228, PR China
| | - Hehe Du
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China
| | - Lin Zhu
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Collaborative Innovation Center of Marine Science and Technology, College of Marine Science, Hainan University, Haikou, Hainan, 570228, PR China
| | - Na Zhao
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China
| | - Shengnan Zhang
- Collaborative Innovation Center of Marine Science and Technology, College of Marine Science, Hainan University, Haikou, Hainan, 570228, PR China
| | - Zhenjie Cao
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Collaborative Innovation Center of Marine Science and Technology, College of Marine Science, Hainan University, Haikou, Hainan, 570228, PR China
| | - Yongcan Zhou
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Collaborative Innovation Center of Marine Science and Technology, College of Marine Science, Hainan University, Haikou, Hainan, 570228, PR China.
| | - Yun Sun
- State Key Laboratory of Marine Resource Utilization in South China Sea, Hainan University, PR China; Collaborative Innovation Center of Marine Science and Technology, College of Marine Science, Hainan University, Haikou, Hainan, 570228, PR China.
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2
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Noronha MA, D'Angelo NA, Pérez-Sánchez G, Severino P, Ann Foglio M, Greaves TL, F. B. Pereira J, Lopes AM. Self-assembling micelles of lipopolysaccharides (LPS) for loading hydrophobic (bio)molecules. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.121154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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3
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Jiang C, Wang S. Identification and functional characterization of bactericidal permeability/increasing protein (BPI) from frog Nanorana yunnanensis (Paa yunnanensis). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2022; 137:104517. [PMID: 36028172 DOI: 10.1016/j.dci.2022.104517] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2022] [Revised: 08/13/2022] [Accepted: 08/18/2022] [Indexed: 06/15/2023]
Abstract
Bactericidal permeability/increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) have been most extensively studied in mammals, but little information is available regarding BPI and LBP in Amphibia. In this study we showed that the cDNA of BPI in the frog N. yunnanensis (P. yunnanensis) encoded a 490-amino-acid-long protein, the predicted tertiary structure appears closely similar to mammalian BPIs in terms of sequence and structure. Like mammalian BPI gene, the frog gene nybpi was widely expressed in various tissues and was inducible by challenge with LPS or Gram-negative bacterium. We also showed that recombinant NyBPI, resembling mammalian BPIs, specifically binds with LPS. In addition, the recombinant NyBPI displayed antibacterial activity against Gram-negative bacteria Vibrio anguillarum in a dose-dependent manner. These results indicate that NyBPI may play an important role in an immune response against bacteria in amphibians.
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Affiliation(s)
- Chengyan Jiang
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, Yunnan, 661199, China.
| | - Shaolong Wang
- College of Biological and Agricultural Sciences, Honghe University, Mengzi, Yunnan, 661199, China
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4
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Ciesielska A, Krawczy M, Sas-Nowosielska H, Hromada-Judycka A, Kwiatkowska K. CD14 recycling modulates LPS-induced inflammatory responses of murine macrophages. Traffic 2022; 23:310-330. [PMID: 35411668 DOI: 10.1111/tra.12842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 03/07/2022] [Accepted: 04/01/2022] [Indexed: 11/28/2022]
Abstract
TLR4 is activated by the bacterial endotoxin lipopolysaccharide (LPS) and triggers two pro-inflammatory signaling cascades: a MyD88-dependent one in the plasma membrane, and the following TRIF-dependent one in endosomes. An inadequate inflammatory reaction can be detrimental for the organism by leading to sepsis. Therefore, novel approaches to therapeutic modulation of TLR4 signaling are being sought after. The TLR4 activity is tightly connected with the presence of CD14, a GPI-anchored protein that transfers LPS monomers to the receptor and controls its endocytosis. In this study we focused on CD14 trafficking as a still poorly understood factor affecting TLR4 activity. Two independent assays were used to show that after endocytosis CD14 can recycle back to the plasma membrane in both unstimulated and stimulated cells. This route of CD14 trafficking can be controlled by sorting nexins (SNX) 1, 2, and 6, and is important for maintaining the surface level and the total level of CD14, but can also affect the amount of TLR4. Silencing of these SNXs attenuated especially the CD14-dependent endosomal signaling of TLR4, making them a new target for therapeutic regulation of the inflammatory response of macrophages to LPS.
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Affiliation(s)
- Anna Ciesielska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Marta Krawczy
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Hanna Sas-Nowosielska
- Laboratory of Molecular Basis of Cell Motility, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093 Warsaw, Poland
| | - Aneta Hromada-Judycka
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, Warsaw, Poland
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5
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Theprungsirikul J, Skopelja-Gardner S, Wierzbicki RM, Sessions KJ, Rigby WFC. Differential Enhancement of Neutrophil Phagocytosis by Anti-Bactericidal/Permeability-Increasing Protein Antibodies. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2021; 207:777-783. [PMID: 34272233 PMCID: PMC8354091 DOI: 10.4049/jimmunol.2100378] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 05/18/2021] [Indexed: 12/27/2022]
Abstract
Bactericidal/permeability-increasing protein (BPI) plays a major role in innate immunity through the ability of the N-terminal domain (NTD) to bind LPS, mediate cytotoxicity, and block LPS-induced inflammation. The C-terminal domain mediates phagocytosis of bacteria bound to the NTD. These two domains are linked by a surface-exposed loop at amino acids 231-249 for human BPI, known as the "hinge region." Autoantibodies to human BPI are prevalent in many chronic lung diseases; their presence is strongly correlated with Pseudomonas aeruginosa and with worse lung function in patients with cystic fibrosis and bronchiectasis. Although prior literature has reported BPI neutralization effect with autoantibodies targeting either NTD or C-terminal domain, the functionality of BPI Ab to the hinge region has never been investigated. Here, we report that Ab responses to the BPI hinge region mediate a remarkably selective potentiation of BPI-dependent phagocytosis of P. aeruginosa with both human and murine neutrophils in vitro and in vivo. These findings indicate that autoantibodies to the BPI hinge region might enhance bacterial clearance.
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Affiliation(s)
- Jomkuan Theprungsirikul
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH; and
| | - Sladjana Skopelja-Gardner
- Division of Rheumatology, Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH
| | - Rachel M Wierzbicki
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH; and
| | - Katherine J Sessions
- Division of Rheumatology, Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH
| | - William F C Rigby
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH; and
- Division of Rheumatology, Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH
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6
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Theprungsirikul J, Skopelja-Gardner S, Rigby WF. Killing three birds with one BPI: Bactericidal, opsonic, and anti-inflammatory functions. J Transl Autoimmun 2021; 4:100105. [PMID: 34142075 PMCID: PMC8187252 DOI: 10.1016/j.jtauto.2021.100105] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2021] [Revised: 05/10/2021] [Accepted: 05/15/2021] [Indexed: 01/17/2023] Open
Abstract
Bactericidal/permeability-increasing protein (BPI) is an anti-microbial protein predominantly expressed in azurophilic granules of neutrophils. BPI has been shown to mediate cytocidal and opsonic activity against Gram-negative bacteria, while also blunting inflammatory activity of lipopolysaccharide (LPS). Despite awareness of these functions in vitro, the magnitude of the contribution of BPI to innate immunity remains unclear, and the nature of the functional role of BPI in vivo has been submitted to limited investigation. Understanding this role takes on particular interest with the recognition that autoimmunity to BPI is tightly linked to a specific infectious trigger like Pseudomonas aeruginosa in chronic lung infection. This has led to the notion that anti-BPI autoantibodies compromise the activity of BPI in innate immunity against P. aeruginosa, which is primarily mediated by neutrophils. In this review, we explore the three main mechanisms in bactericidal, opsonic, and anti-inflammatory of BPI. We address the etiology and the effects of BPI autoreactivity on BPI function. We explore BPI polymorphism and its link to multiple diseases. We summarize BPI therapeutic potential in both animal models and human studies, as well as offer therapeutic approaches to designing a sustainable and promising BPI molecule.
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Affiliation(s)
- Jomkuan Theprungsirikul
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Sladjana Skopelja-Gardner
- Division of Rheumatology, Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - William F.C. Rigby
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
- Division of Rheumatology, Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
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7
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Theprungsirikul J, Skopelja-Gardner S, Burns AS, Wierzbicki RM, Rigby WFC. Bactericidal/Permeability-Increasing Protein Preeminently Mediates Clearance of Pseudomonas aeruginosa In Vivo via CD18-Dependent Phagocytosis. Front Immunol 2021; 12:659523. [PMID: 33981306 PMCID: PMC8107240 DOI: 10.3389/fimmu.2021.659523] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 04/07/2021] [Indexed: 12/30/2022] Open
Abstract
Chronic Pseudomonas aeruginosa infection mysteriously occurs in the airways of patients with cystic fibrosis (CF), bronchiectasis (BE), and chronic obstructive pulmonary disease (COPD) in the absence of neutrophil dysfunction or neutropenia and is strongly associated with autoimmunity to bactericidal permeability-increasing protein (BPI). Here, we define a critical role for BPI in in vivo immunity against P. aeruginosa. Wild type and BPI-deficient (Bpi-/-) mice were infected with P. aeruginosa, and bacterial clearance, cell infiltrates, cytokine production, and in vivo phagocytosis were quantified. Bpi-/- mice exhibited a decreased ability to clear P. aeruginosa in vivo in concert with increased neutrophil counts and cytokine release. Bpi-/- neutrophils displayed decreased phagocytosis that was corrected by exogenous BPI in vitro. Exogenous BPI also enhanced clearance of P. aeruginosa in Bpi-/- mice in vivo by increasing P. aeruginosa uptake by neutrophils in a CD18-dependent manner. These data indicate that BPI plays an essential role in innate immunity against P. aeruginosa through its opsonic activity and suggest that perturbations in BPI levels or function may contribute to chronic lung infection with P. aeruginosa.
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Affiliation(s)
- Jomkuan Theprungsirikul
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Sladjana Skopelja-Gardner
- Division of Rheumatology, Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Ashley S. Burns
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - Rachel M. Wierzbicki
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
| | - William F. C. Rigby
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
- Division of Rheumatology, Department of Medicine, Geisel School of Medicine at Dartmouth, Lebanon, NH, United States
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Ciesielska A, Matyjek M, Kwiatkowska K. TLR4 and CD14 trafficking and its influence on LPS-induced pro-inflammatory signaling. Cell Mol Life Sci 2020; 78:1233-1261. [PMID: 33057840 PMCID: PMC7904555 DOI: 10.1007/s00018-020-03656-y] [Citation(s) in RCA: 542] [Impact Index Per Article: 135.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/25/2020] [Accepted: 09/22/2020] [Indexed: 02/07/2023]
Abstract
Toll-like receptor (TLR) 4 belongs to the TLR family of receptors inducing pro-inflammatory responses to invading pathogens. TLR4 is activated by lipopolysaccharide (LPS, endotoxin) of Gram-negative bacteria and sequentially triggers two signaling cascades: the first one involving TIRAP and MyD88 adaptor proteins is induced in the plasma membrane, whereas the second engaging adaptor proteins TRAM and TRIF begins in early endosomes after endocytosis of the receptor. The LPS-induced internalization of TLR4 and hence also the activation of the TRIF-dependent pathway is governed by a GPI-anchored protein, CD14. The endocytosis of TLR4 terminates the MyD88-dependent signaling, while the following endosome maturation and lysosomal degradation of TLR4 determine the duration and magnitude of the TRIF-dependent one. Alternatively, TLR4 may return to the plasma membrane, which process is still poorly understood. Therefore, the course of the LPS-induced pro-inflammatory responses depends strictly on the rates of TLR4 endocytosis and trafficking through the endo-lysosomal compartment. Notably, prolonged activation of TLR4 is linked with several hereditary human diseases, neurodegeneration and also with autoimmune diseases and cancer. Recent studies have provided ample data on the role of diverse proteins regulating the functions of early, late, and recycling endosomes in the TLR4-induced inflammation caused by LPS or phagocytosis of E. coli. In this review, we focus on the mechanisms of the internalization and intracellular trafficking of TLR4 and CD14, and also of LPS, in immune cells and discuss how dysregulation of the endo-lysosomal compartment contributes to the development of diverse human diseases.
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Affiliation(s)
- Anna Ciesielska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland.
| | - Marta Matyjek
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology of Polish Academy of Sciences, 3 Pasteur St., 02-093, Warsaw, Poland
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9
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Increased levels of BPI-ANCA in patients with primary Sjögren’s syndrome are associated with lung involvement. Clin Biochem 2020; 83:43-48. [DOI: 10.1016/j.clinbiochem.2020.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 05/09/2020] [Accepted: 05/30/2020] [Indexed: 11/21/2022]
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10
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Yu Y, Song G. Lipopolysaccharide-Binding Protein and Bactericidal/Permeability-Increasing Protein in Lipid Metabolism and Cardiovascular Diseases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:27-35. [PMID: 32705592 DOI: 10.1007/978-981-15-6082-8_3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Lipopolysaccharide-binding protein (LBP) and bactericidal/permeability-increasing protein (BPI) are the main members of BPI-like family based on the similar protein structure and conserved gene homology. Both LBP and BPI participate in lipid metabolism and thereby involve in pathogenesis of certain cardiovascular diseases. This chapter describes four aspects: (1) the loci of BPI and LBP in genome, (2) the characteristics of the cDNAs and expression patterns of LBP and BPI, (3) the structures and functions of LBP and BPI, and (4) the LBP and BPI in lipid metabolism and cardiovascular research.
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Affiliation(s)
- Yang Yu
- Institute of Atherosclerosis, Shandong First Medical University, Shandong, China.
| | - Guohua Song
- Institute of Atherosclerosis, Shandong First Medical University, Shandong, China
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Bülow S, Zeller L, Werner M, Toelge M, Holzinger J, Entzian C, Schubert T, Waldow F, Gisch N, Hammerschmidt S, Gessner A. Bactericidal/Permeability-Increasing Protein Is an Enhancer of Bacterial Lipoprotein Recognition. Front Immunol 2018; 9:2768. [PMID: 30581431 PMCID: PMC6293271 DOI: 10.3389/fimmu.2018.02768] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/12/2018] [Indexed: 12/12/2022] Open
Abstract
Adequate perception of immunologically important pathogen-associated molecular patterns like lipopolysaccharide and bacterial lipoproteins is essential for efficient innate and adaptive immune responses. In the context of Gram-negative infection, bactericidal/permeability-increasing protein (BPI) neutralizes endotoxic activity of lipopolysaccharides, and thus prohibits hyperactivation. So far, no immunological function of BPI has been described in Gram-positive infections. Here, we show a significant elevation of BPI in Gram-positive meningitis and, surprisingly, a positive correlation between BPI and pro-inflammatory markers like TNFα. To clarify the underlying mechanisms, we identify BPI ligands of Gram-positive origin, specifically bacterial lipopeptides and lipoteichoic acids, and determine essential structural motifs for this interaction. Importantly, the interaction of BPI with these newly defined ligands significantly enhances the immune response in peripheral blood mononuclear cells (PBMCs) mediated by Gram-positive bacteria, and thereby ensures their sensitive perception. In conclusion, we define BPI as an immune enhancing pattern recognition molecule in Gram-positive infections.
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Affiliation(s)
- Sigrid Bülow
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
| | - Lisa Zeller
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
| | - Maren Werner
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
| | - Martina Toelge
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
| | - Jonas Holzinger
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
| | | | | | - Franziska Waldow
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Nicolas Gisch
- Division of Bioanalytical Chemistry, Priority Area Infections, Research Center Borstel, Leibniz Lung Center, Borstel, Germany
| | - Sven Hammerschmidt
- Department of Molecular Genetics and Infection Biology, Center for Functional Genomcis of Microbes, Interfaculty Institute for Genetics and Functional Genomics, University of Greifswald, Greifswald, Germany
| | - André Gessner
- Institute of Clinical Microbiology and Hygiene, University Hospital Regensburg, Regensburg, Germany
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12
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Lu HX, Sun JH, Wen DL, Du J, Zeng L, Zhang AQ, Jiang JX. LBP rs2232618 polymorphism contributes to risk of sepsis after trauma. World J Emerg Surg 2018; 13:52. [PMID: 30479651 PMCID: PMC6240187 DOI: 10.1186/s13017-018-0214-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2018] [Accepted: 11/01/2018] [Indexed: 12/17/2022] Open
Abstract
Background Previous study revealed that rs2232618 polymorphism (Phe436Leu) within LBP gene is a functional variant and associated with susceptibility of sepsis in traumatic patients. Our aim was to confirm the reported association by enlarging the population sample size and perform a meta-analysis to find additional evidence. Methods Traumatic patients from Southwest (n = 1296) and Southeast (n = 445) of China were enrolled in our study. After genotyping, the relationship between rs2232618 and the risk of sepsis was analyzed. Furthermore, we proceeded with a comprehensive literature search and meta-analysis to determine whether the rs2232618 polymorphism conferred susceptibility to sepsis. Results Significance correlation was observed between rs2232618 and risk of sepsis in Southwest patients (P = 0.002 for the dominant model, P = 0.006 for the recessive model). The association was confirmed in Southeast cohort (P = 0.005 for the dominant model) and overall combined cohorts (P = 4.5 × 10-4, P = 0.041 for the dominant and recessive model). Multiple logistical regression analyses suggested that rs2232618 polymorphism was related to higher risk of sepsis (OR = 1.77, 95% CI = 1.26-2.48, P = 0.001 in Southwest patients; OR = 2.11, 95% CI = 1.24-3.58, P = 0.006 in Southeast cohort; OR = 1.54, 95% CI = 1.34-2.08, P = 0.006 in overall cohort). Furthermore, meta-analysis of four studies (including the present study) confirmed that rs2232618 within LBP increased the risk of sepsis (OR = 1.75, P < 0.001 for the dominant model; OR = 6.08, P = 0.003 for the recessive model; OR = 2.72, P < 0.001 for the allelic model). Conclusions The results from our replication study and meta-analysis provided firm evidence that rs2232618T allele significantly increased the risk of sepsis.
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Affiliation(s)
- Hong-Xiang Lu
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042 China
| | - Jian-Hui Sun
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042 China
| | - Da-Lin Wen
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042 China
| | - Juan Du
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042 China
| | - Ling Zeng
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042 China
| | - An-Qiang Zhang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042 China
| | - Jian-Xin Jiang
- State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing, 400042 China
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Abstract
In humans and other mammals, recognition of endotoxins—abundant surface lipopolysaccharides (LPS) of Gram-negative bacteria—provides a potent stimulus for induction of inflammation and mobilization of host defenses. The structurally unique lipid A region of LPS is the principal determinant of this pro-inflammatory activity. This region of LPS is normally buried within the bacterial outer membrane and aggregates of purified LPS, making even more remarkable its picomolar potency and the ability of discrete variations in lipid A structure to markedly alter the pro-inflammatory activity of LPS. Two recognition systems—MD-2/TLR4 and “LPS-sensing” cytosolic caspases—together confer LPS responsiveness at the host cell surface, within endosomes, and at sites physically accessible to the cytosol. Understanding how the lipid A of LPS is delivered and recognized at these diverse sites is crucial to understanding how the magnitude and character of the inflammatory responses are regulated.
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Affiliation(s)
- Jerrold Weiss
- Inflammation Program and Departments of Internal Medicine and Microbiology, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
| | - Jason Barker
- Inflammation Program and Departments of Internal Medicine and Microbiology, University of Iowa, Iowa City, Iowa, USA.,Veterans Affairs Medical Center, Iowa City, Iowa, USA
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14
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Liu J, Li G, Chen C, Chen D, Zhou Q. MiR-6835 promoted LPS-induced inflammation of HUVECs associated with the interaction between TLR-4 and AdipoR1 in lipid rafts. PLoS One 2017; 12:e0188604. [PMID: 29190778 PMCID: PMC5708807 DOI: 10.1371/journal.pone.0188604] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Accepted: 11/09/2017] [Indexed: 02/07/2023] Open
Abstract
Background High mortality rate of critically-ill patients could be induced by sepsis and septic shock, which is the extremely life threatening. The purpose of this work is to identify and evaluate the potential regulatory mechanism of LPS-induced inflammation associated with miR-6835 and lipid rafts in HUVECs. Methods The 3’ UTR luciferase activity of AdipoR1 was detected, which was predicted the potential target gene of miR-6835. Moreover, the treated HUVECs with or without inhibitors or mimics of miR-6835 were used. Furthermore, the bio-functions of HUVECs were explored. The protein expression levels of SIRT-1, AMPK, and AdipoR1 were assessed, which were involved in the AdipoR1 signaling pathway. Then, the interaction between TLR-4 and AdipoR1 in lipid rafts and its mediation role on LPS-induced inflammation was investigated in HUVECs. Results MiR-6835 targeted directly on AdipoR1, and suppressed its expression in mRNA (mimics of miR-6835: 0.731±0.016 vs control: 1.527±0.015, P<0.001) and proteins levels, then regulated protein expression of SIRT-1 and AMPK, which were the downstream target genes of AdipoR1 signaling pathway. MiR-6835 enhanced LPS-induced inflammation process in HUVECs (TNF-α: LPS+mimics of miR-6835: 1638.51±78.43 vs LPS: 918.73±39.73, P<0.001; IL-6: LPS+mimics of miR-6835: 1249.35±69.51 vs LPS: 687.52±43.64, P<0.001), which was associated with the interaction between TLR-4 and AdipoR1 in lipid rafts. Conclusions MiR-6835 is the key regulator of LPS-induced inflammation process in HUVECs. The interaction between TLR-4 and AdipoR1 mediated by lipid rafts at membrane of HUVECs with inflammation process induced by miR-6835. Our results demonstrated a hopeful strategy for treatment on sepsis by aiming at lipid rafts and miR-6835.
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Affiliation(s)
- Jiao Liu
- Department of Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Guang Li
- Department of Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Chuang Chen
- Department of Breast and Thyroid Surgery, Renmin Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
| | - Dechang Chen
- Department of Emergency and Critical Care Medicine, Shanghai Changzheng Hospital, Second Military Medical University, Shanghai, People’s Republic of China
| | - Qingshan Zhou
- Department of Critical Care Medicine, Renmin Hospital of Wuhan University, Wuhan, Hubei, People’s Republic of China
- * E-mail:
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15
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Cochet F, Peri F. The Role of Carbohydrates in the Lipopolysaccharide (LPS)/Toll-Like Receptor 4 (TLR4) Signalling. Int J Mol Sci 2017; 18:E2318. [PMID: 29099761 PMCID: PMC5713287 DOI: 10.3390/ijms18112318] [Citation(s) in RCA: 110] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 09/27/2017] [Accepted: 10/30/2017] [Indexed: 12/12/2022] Open
Abstract
The interactions between sugar-containing molecules from the bacteria cell wall and pattern recognition receptors (PRR) on the plasma membrane or cytosol of specialized host cells are the first molecular events required for the activation of higher animal's immune response and inflammation. This review focuses on the role of carbohydrates of bacterial endotoxin (lipopolysaccharide, LPS, lipooligosaccharide, LOS, and lipid A), in the interaction with the host Toll-like receptor 4/myeloid differentiation factor 2 (TLR4/MD-2) complex. The lipid chains and the phosphorylated disaccharide core of lipid A moiety are responsible for the TLR4 agonist action of LPS, and the specific interaction between MD-2, TLR4, and lipid A are key to the formation of the activated complex (TLR4/MD-2/LPS)₂, which starts intracellular signalling leading to nuclear factors activation and to production of inflammatory cytokines. Subtle chemical variations in the lipid and sugar parts of lipid A cause dramatic changes in endotoxin activity and are also responsible for the switch from TLR4 agonism to antagonism. While the lipid A pharmacophore has been studied in detail and its structure-activity relationship is known, the contribution of core saccharides 3-deoxy-d-manno-octulosonic acid (Kdo) and heptosyl-2-keto-3-deoxy-octulosonate (Hep) to TLR4/MD-2 binding and activation by LPS and LOS has been investigated less extensively. This review focuses on the role of lipid A, but also of Kdo and Hep sugars in LPS/TLR4 signalling.
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Affiliation(s)
- Florent Cochet
- Department of Biotechnology and Biosciences, University of Milano Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
| | - Francesco Peri
- Department of Biotechnology and Biosciences, University of Milano Bicocca, Piazza della Scienza, 2, 20126 Milano, Italy.
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The Mucosal Antibacterial Response Profile and Fecal Microbiota Composition Are Linked to the Disease Course in Patients with Newly Diagnosed Ulcerative Colitis. Inflamm Bowel Dis 2017; 23:956-966. [PMID: 28445247 DOI: 10.1097/mib.0000000000001130] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND The clinical disease course of ulcerative colitis (UC) varies substantially between individuals and can currently not be reliably predicted. The gut microbiota and the host's immune defense are key players for gut homeostasis and may be linked to disease outcome. The aim of this study was to determine fecal microbiota composition and mucosal antibacterial response profile in untreated patients with newly diagnosed UC and the impact of these factors on disease course. METHODS Stool samples and intestinal biopsies were obtained from therapy-naive newly diagnosed patients with UC. Patients were defined to have mild or moderate/severe disease course assessed by disease activity during the 3 years follow-up. Fecal microbiota was analyzed by the GA-map Dysbiosis test (n = 18), and gene expression in intestinal biopsies was analyzed by RT Profiler polymerase chain reaction array (n = 13) and real-time polymerase chain reaction (n = 44). RESULTS At the time of diagnosis of UC, the fecal microbiota composition discriminated between patients with mild versus moderate/severe disease course. Also, the mucosal antibacterial gene expression response profile differed between patients with mild versus moderate/severe disease course with bactericidal/permeability-increasing protein (BPI) being most important for the discrimination. Mucosal bactericidal/permeability-increasing protein gene expression at diagnosis was higher in patients with mild versus moderate/severe disease course when confirmed in a larger patient cohort (P = 0.0004, n = 44) and was a good predictor for the number of flares during the 3 years follow-up (R = 0.395, P < 0.0001). CONCLUSIONS In patients with newly diagnosed UC, fecal microbiota composition and mucosal antibacterial response profile, especially bactericidal/permeability-increasing protein, are linked to disease course.
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Lee S, Elvitigala DAS, Lee S, Kim HC, Park HC, Lee J. Molecular characterization of a bactericidal permeability-increasing protein/lipopolysaccharide-binding protein from black rockfish (Sebastes schlegelii): Deciphering its putative antibacterial role. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2017; 67:266-275. [PMID: 27663679 DOI: 10.1016/j.dci.2016.09.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 09/19/2016] [Accepted: 09/19/2016] [Indexed: 06/06/2023]
Abstract
Bactericidal permeability-increasing protein (BPI)/lipopolysaccharide (LPS) binding proteins (LBPs) are well-known proteins that play an indispensable role in host antimicrobial defense. Herein, we report a homolog of BPI/LBP from black rockfish (Sebastes schlegelii) (designated as RfBPI/LBP) and characterize its structural and functional features at the molecular level. We identified the putative complete open reading frame (1422 bp) of RfLBP that encodes a 474 amino acid protein with a predicted molecular mass of ∼51.5 kDa. The primary protein sequence of RfBPI/LBP contains domain features of BPI/LBP family proteins and shares significant sequence consistency with its homologs. Our phylogenetic analysis clearly demonstrated the vertebrate ancestral origin of RfBPI/LBP, further reinforcing its evolutionary relationship with teleostean homologs. Recombinant RfBPI/LBP demonstrated in vitro LPS-binding activity and antibacterial activity against Escherichia coli, but not against Streptococcus iniae. Moreover, RfBPI/LBP exhibited temporal transcriptional activation against pathogens and pathogen-associated molecular patterns. Collectively, our findings suggest that RfBPI/LBP plays an essential role in host antimicrobial defense, plausibly through selective eradication of invading bacteria.
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Affiliation(s)
- Seongdo Lee
- Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - Don Anushka Sandaruwan Elvitigala
- Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Department of Zoology, University of Sri Jayewardenepura, Gangodawila, Nugegoda, 10250, Sri Lanka
| | - Sukkyoung Lee
- Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea
| | - Hyun Chul Kim
- Genetics & Breeding Research Center, National Institute of Fisheries Science, Geoje, 53334, Republic of Korea
| | - Hae-Chul Park
- Graduate School of Medicine, Korea University, Ansan, Gyeonggido, 15355, Republic of Korea.
| | - Jehee Lee
- Department of Marine Life Sciences, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea; Fish Vaccine Research Center, Jeju National University, Jeju Self-Governing Province, 63243, Republic of Korea.
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18
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Wacker MA, Teghanemt A, Weiss JP, Barker JH. High-affinity caspase-4 binding to LPS presented as high molecular mass aggregates or in outer membrane vesicles. Innate Immun 2017; 23:336-344. [PMID: 28409545 DOI: 10.1177/1753425917695446] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Caspases of the non-canonical inflammasome (caspases -4, -5, and -11) directly bind endotoxin (LOS/LPS) and can be activated in the absence of any co-factors. Models of LPS-induced caspase activation have postulated that 1:1 binding of endotoxin monomers to caspase trigger caspase oligomerization and activation, analogous to that established for endotoxin-induced activation of MD-2/TLR4. However, using metabolically radiolabeled LOS and LPS, we now show high affinity and selective binding of caspase-4 to high molecular mass aggregates of purified endotoxin and to endotoxin-rich outer membrane vesicles without formation of 1:1 endotoxin:caspase complexes. Thus, our findings demonstrate markedly different endotoxin recognition properties of caspase-4 from that of MD-2/TLR4 and strongly suggest that activation of caspase-4 (and presumably caspase-5 and caspase-11) are mediated by interactions with activating endotoxin-rich membrane interfaces rather than by endotoxin monomers.
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Affiliation(s)
- Mark A Wacker
- 1 Department of Biology, Central Michigan University, Mt. Pleasant, MI, USA
| | - Athmane Teghanemt
- 2 Inflammation Program, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,3 Department of Internal Medicine, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA
| | - Jerrold P Weiss
- 2 Inflammation Program, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,3 Department of Internal Medicine, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,4 Department of Microbiology, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA
| | - Jason H Barker
- 2 Inflammation Program, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,3 Department of Internal Medicine, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA.,4 Department of Microbiology, University of Iowa, and Iowa City VA Health Care System, Iowa City, IA, USA
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19
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Ryu JK, Kim SJ, Rah SH, Kang JI, Jung HE, Lee D, Lee HK, Lee JO, Park BS, Yoon TY, Kim HM. Reconstruction of LPS Transfer Cascade Reveals Structural Determinants within LBP, CD14, and TLR4-MD2 for Efficient LPS Recognition and Transfer. Immunity 2016; 46:38-50. [PMID: 27986454 DOI: 10.1016/j.immuni.2016.11.007] [Citation(s) in RCA: 249] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 10/08/2016] [Accepted: 10/21/2016] [Indexed: 01/29/2023]
Abstract
Lipopolysaccharide (LPS), the major component of the outer membrane of Gram-negative bacteria, binds Toll-like receptor 4 (TLR4)-MD2 complex and activates innate immune responses. LPS transfer to TLR4-MD2 is catalyzed by both LPS binding protein (LBP) and CD14. To define the sequential molecular interactions underlying this transfer, we reconstituted in vitro the entire LPS transfer process from LPS micelles to TLR4-MD2. Using electron microscopy and single-molecule approaches, we characterized the dynamic intermediate complexes for LPS transfer: LBP-LPS micelles, CD14-LBP-LPS micelle, and CD14-LPS-TLR4-MD2 complex. A single LBP molecule bound longitudinally to LPS micelles catalyzed multi-rounds of LPS transfer to CD14s that rapidly dissociated from LPB-LPS complex upon LPS transfer via electrostatic interactions. Subsequently, the single LPS molecule bound to CD14 was transferred to TLR4-MD2 in a TLR4-dependent manner. The definition of the structural determinants of the LPS transfer cascade to TLR4 may enable the development of targeted therapeutics for intervention in LPS-induced sepsis.
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Affiliation(s)
- Je-Kyung Ryu
- National Creative Research Initiative Center for Single-Molecule Systems Biology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; Department of Physics, KAIST, Daejeon 34141, Korea
| | - Soo Jin Kim
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon 34141, Korea
| | - Sang-Hyun Rah
- National Creative Research Initiative Center for Single-Molecule Systems Biology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; Department of Physics, KAIST, Daejeon 34141, Korea; Center for Nanomedicine, Institute for Basic Science (IBS), Yonsei University, Seoul 03722, Korea; Yonsei-IBS Institute, Yonsei University, Seoul 03722, Korea
| | - Ji In Kang
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon 34141, Korea
| | - Hi Eun Jung
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon 34141, Korea
| | - Dongsun Lee
- Graduate School of Medical Science & Engineering, KAIST, Daejeon 34141, Korea
| | - Heung Kyu Lee
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon 34141, Korea; Graduate School of Medical Science & Engineering, KAIST, Daejeon 34141, Korea
| | - Jie-Oh Lee
- Department of Chemistry, KAIST, Daejeon 34141, Korea
| | - Beom Seok Park
- Department of Biomedical Laboratory Science, College of Health Science, Eulji University, Seongnam 461-713, Korea
| | - Tae-Young Yoon
- National Creative Research Initiative Center for Single-Molecule Systems Biology, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea; Department of Physics, KAIST, Daejeon 34141, Korea; Center for Nanomedicine, Institute for Basic Science (IBS), Yonsei University, Seoul 03722, Korea; Yonsei-IBS Institute, Yonsei University, Seoul 03722, Korea.
| | - Ho Min Kim
- Biomedical Science and Engineering Interdisciplinary Program, KAIST, Daejeon 34141, Korea; Graduate School of Medical Science & Engineering, KAIST, Daejeon 34141, Korea.
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Gioannini T, Teghanemt A, Zhang D, Levis E, Weiss J. Monomeric endotoxin:protein complexes are essential for TLR4-dependent cell activation. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519050110020801] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Potent TLR4-dependent cell activation by Gram-negative bacterial endotoxin depends on sequential endotoxin—protein and protein—protein interactions with LBP, CD14, MD-2 and TLR4. LBP and CD14 combine, in an albumin-dependent fashion, to extract single endotoxin molecules from purified endotoxin aggregates (Eagg) or the bacterial outer membrane and form monomeric endotoxin:CD14 complexes that are the preferred presentation of endotoxin for transfer to MD-2. Endotoxin in endotoxin:CD14 is readily transferred to MD-2, again in an albumin-dependent manner, to form monomeric endotoxin:MD-2 complex. This monomeric endotoxin:protein complex (endotoxin:MD-2) activates TLR4 at picomolar concentrations, independently of albumin, and is, therefore, the apparent ligand in endotoxin-dependent TLR4 activation. Tetra-, penta-, and hexa-acylated forms of meningococcal endotoxin (LOS) react similarly with LBP, CD14, and MD-2 to form endotoxin:MD-2 complexes. However, tetra- and penta-acylated LOS:MD-2 complexes are less potent TLR4 agonists than hexa-acylated LOS:MD-2. This is mirrored in the reduced activity of tetra-, penta- versus hexa-acylated LOS aggregates (LOSagg) + LBP toward cells containing mCD14, MD-2, and TLR4. Therefore, changes in agonist potency of under-acylated meninigococcal LOS are determined by differences in properties of monomeric endotoxin:MD-2.
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Affiliation(s)
- T.L. Gioannini
- Department of Internal Medicine, University of Iowa and the Veterans' Administration Medical Center, Iowa City, Iowa, USA, Department of Biochemistry, University of Iowa and the Veterans' Administration Medical Center, Iowa City, Iowa, USA,
| | - A. Teghanemt
- Department of Internal Medicine, University of Iowa and the Veterans' Administration Medical Center, Iowa City, Iowa, USA
| | - DeS. Zhang
- Department of Internal Medicine, University of Iowa and the Veterans' Administration Medical Center, Iowa City, Iowa, USA
| | - E.N. Levis
- Department of Internal Medicine, University of Iowa and the Veterans' Administration Medical Center, Iowa City, Iowa, USA
| | - J.P. Weiss
- Department of Internal Medicine, University of Iowa and the Veterans' Administration Medical Center, Iowa City, Iowa, USA, Department of Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa and the Veterans' Administration Medical Center, Iowa City, Iowa, USA
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21
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Gioannini TL, Teghanemt A, Zarember KA, Weiss JP. Regulation of interactions of endotoxin with host cells. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519030090060301] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Potent Toll-like receptor 4 (TLR4)-dependent cell activation by endotoxin requires lipopolysaccharide-binding protein (LBP) and CD14-dependent delivery of endotoxin to cells containing MD-2 and TLR4. We have used metabolically labeled [14C] meningococcal lipooligosaccharide (LOS), purified recombinant endotoxin-binding proteins, and cultured endothelial cells to better define protein: endotoxin intermediates key in cell activation in the absence of functional membrane (m) CD14. Protein:endotoxin complexes or aggregates ( agg) were purified by gel sieving and characterized by immunocapture and bio-assays. Cell activation closely correlated with LBP, albumin and soluble (s) CD14-dependent conversion of endotoxin agg (Mr≥ 20 × 106) to monomeric (M ~55 × 103) endotoxin:sCD14 complexes. Ordered interaction of LBP (+ albumin) and sCD14 withrLOS agg was required for the efficient formation of a bioactive endotoxin:sCD14 complex and potent cell activation. Increasing the ratio of LBP/sCD14 or addition of bactericidal/permeability-increasing protein (BPI) reduced accumulation of endotoxin:sCD14 complexes and instead yielded aggregates of endotoxin (Mr~1—20 × 106) containing LBP or BPI that were taken up by cells in a CD14- and TLR4-independent manner without inducing pro-inflammatory responses. These findings strongly suggest that host machinery linked to TLR4-dependent cellular activation or TLR4-independent cellular clearance of endotoxin selectively recognizes different protein:endotoxin complexes. At the outset of infection, the low concentrations of LBP present and absence of extracellular BPI favor formation of pro-inflammatory endotoxin:CD14 complexes. The mobilization of LBP and BPI that is triggered by inflammation directs endotoxin for clearance and hence resolution of endotoxin-triggered inflammation.
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Affiliation(s)
- Theresa L. Gioannini
- Departments of Internal Medicine, Division of Infectious Diseases and The Inflammation Program, University of Iowa, Iowa City, Iowa, Department of Biochemistry, University of Iowa, Iowa City, Iowa
| | - Athmane Teghanemt
- Departments of Internal Medicine, Division of Infectious Diseases and The Inflammation Program, University of Iowa, Iowa City, Iowa
| | - Kol A. Zarember
- Department of Molecular Biology, Genentech, Inc., South San Francisco, California, USA
| | - Jerrold P. Weiss
- Departments of Internal Medicine, Division of Infectious Diseases and The Inflammation Program, University of Iowa, Iowa City, Iowa, , Microbiology, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa, Iowa City Veterans' Administration Medical Center, Iowa City, Iowa, USA
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22
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Satoh M, Iwahori T, Sugawara N, Yamazaki M. Liver argininosuccinate synthase binds to bacterial lipopolysaccharides and lipid A and inactivates their biological activities. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519060120010301] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The liver is known to clear and detoxify circulating lipopolysaccharide (LPS). To characterize the molecules involved in this process in the liver, we attempted to purify mouse liver protein(s) that can interact with lipid A, a biologically active portion of LPS. By partially purifying the inactivating activity against a synthetic lipid A analog, we observed the enrichment of a 45-kDa protein in the active fractions. The internal amino acid sequences of the protein were identical with those of argininosuccinate synthase (EC 6.3.4.5). To examine whether argininosuccinate synthase can interact with lipid A, we purified the enzyme from mouse liver and found the co-elevation of the specific enzyme activity and specific lipid A-inactivating activity, indicating that argininosuccinate synthase is the major lipid A-interacting protein in liver. Argininosuccinate synthase also inhibited the biological activities (macrophage activation and Limulus test) of natural lipid A and rough-type LPS but not smooth-type LPS. The enzyme activity was inhibited by lipid A and rough-type LPS and also by smooth-type LPS. Native gel electrophoresis of a mixture of argininosuccinate synthase and LPS and immunoprecipitation of a mixture of argininosuccinate synthase and [3H]-LPS with anti-argininosuccinate synthase antiserum showed that argininosuccinate synthase stably bound lipid A and LPS. These findings, together, indicate that argininosuccinate synthase can effectively bind LPS in the liver.
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Affiliation(s)
- Motonobu Satoh
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, Japan,-u.ac.jp
| | - Tsuguya Iwahori
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, Japan
| | - Naoki Sugawara
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, Japan
| | - Masatoshi Yamazaki
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamiko, Kanagawa, Japan
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23
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Sim DW, Kim JH, Kim HY, Jang JH, Lee WC, Kim EH, Park PJ, Lee KH, Won HS. Structural identification of the lipopolysaccharide-binding capability of a cupin-family protein from Helicobacter pylori. FEBS Lett 2016; 590:2997-3004. [PMID: 27466800 DOI: 10.1002/1873-3468.12332] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2016] [Revised: 07/19/2016] [Accepted: 07/19/2016] [Indexed: 01/26/2023]
Abstract
We solved the crystal structure of a functionally uncharacterized protein, HP0902, from Helicobacter pylori. Its structure demonstrated an all-β cupin fold that cannot bind metal ions due to the absence of a metal-binding histidine that is conserved in many metallo-cupins. In contrast, isothermal titration calorimetry and NMR titration demonstrated that HP0902 is able to bind bacterial endotoxin lipopolysaccharides (LPS) through its surface-exposed loops, where metal-binding sites are usually found in other metallo-cupins. This report constitutes the first identification of an LPS-interacting protein, both in the cupin family and in H. pylori. Furthermore, identification of the ability of HP0902 to bind LPS uncovers a putative role for this protein in H. pylori pathogenicity.
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Affiliation(s)
- Dae-Won Sim
- Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical and Health Science, Konkuk University, Chungbuk, Korea
| | - Ji-Hun Kim
- Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical and Health Science, Konkuk University, Chungbuk, Korea
| | - Hye-Yeon Kim
- Protein Structure Group, Korea Basic Science Institute, Chungbuk, Korea
| | - Jung-Hwa Jang
- Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical and Health Science, Konkuk University, Chungbuk, Korea
| | - Woo Cheol Lee
- Protein Structure Group, Korea Basic Science Institute, Chungbuk, Korea.,Division of Biotechnology, Korea University, Seoul, Korea
| | - Eun-Hee Kim
- Protein Structure Group, Korea Basic Science Institute, Chungbuk, Korea
| | - Pyo-Jam Park
- Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical and Health Science, Konkuk University, Chungbuk, Korea
| | - Kwang-Ho Lee
- Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical and Health Science, Konkuk University, Chungbuk, Korea
| | - Hyung-Sik Won
- Department of Biotechnology, Research Institute (RIBHS) and College of Biomedical and Health Science, Konkuk University, Chungbuk, Korea
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Sun YY, Sun L. A Teleost Bactericidal Permeability-Increasing Protein Kills Gram-Negative Bacteria, Modulates Innate Immune Response, and Enhances Resistance against Bacterial and Viral Infection. PLoS One 2016; 11:e0154045. [PMID: 27105425 PMCID: PMC4841584 DOI: 10.1371/journal.pone.0154045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 04/07/2016] [Indexed: 12/22/2022] Open
Abstract
Bactericidal/permeability-increasing protein (BPI) is an important factor of innate immunity that in mammals is known to take part in the clearance of invading Gram-negative bacteria. In teleost, the function of BPI is unknown. In the present work, we studied the function of tongue sole (Cynoglossus semilaevis) BPI, CsBPI. We found that CsBPI was produced extracellularly by peripheral blood leukocytes (PBL). Recombinant CsBPI (rCsBPI) was able to bind to a number of Gram-negative bacteria but not Gram-positive bacteria. Binding to bacteria led to bacterial death through membrane permeabilization and structural destruction, and the bound bacteria were more readily taken up by PBL. In vivo, rCsBPI augmented the expression of a wide arrange of genes involved in antibacterial and antiviral immunity. Furthermore, rCsBPI enhanced the resistance of tongue sole against bacterial as well as viral infection. These results indicate for the first time that a teleost BPI possesses immunoregulatory effect and plays a significant role in antibacterial and antiviral defense.
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Affiliation(s)
- Yuan-yuan Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Li Sun
- Key Laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- * E-mail:
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Structural and functional features of a developmentally regulated lipopolysaccharide-binding protein. mBio 2015; 6:e01193-15. [PMID: 26463160 PMCID: PMC4620459 DOI: 10.1128/mbio.01193-15] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mammalian lipopolysaccharide (LPS) binding proteins (LBPs) occur mainly in extracellular fluids and promote LPS delivery to specific host cell receptors. The function of LBPs has been studied principally in the context of host defense; the possible role of LBPs in nonpathogenic host-microbe interactions has not been well characterized. Using the Euprymna scolopes-Vibrio fischeri model, we analyzed the structure and function of an LBP family protein, E. scolopes LBP1 (EsLBP1), and provide evidence for its role in triggering a symbiont-induced host developmental program. Previous studies showed that, during initial host colonization, the LPS of V. fischeri synergizes with peptidoglycan (PGN) monomer to induce morphogenesis of epithelial tissues of the host animal. Computationally modeled EsLBP1 shares some but not all structural features of mammalian LBPs that are thought important for LPS binding. Similar to human LBP, recombinant EsLBP1 expressed in insect cells bound V. fischeri LPS and Neisseria meningitidis lipooligosaccharide (LOS) with nanomolar or greater affinity but bound Francisella tularensis LPS only weakly and did not bind PGN monomer. Unlike human LBP, EsLBP1 did not bind N. meningitidis LOS:CD14 complexes. The eslbp1 transcript was upregulated ~22-fold by V. fischeri at 24 h postinoculation. Surprisingly, this upregulation was not induced by exposure to LPS but, rather, to the PGN monomer alone. Hybridization chain reaction-fluorescent in situ hybridization (HCR-FISH) and immunocytochemistry (ICC) localized eslbp1 transcript and protein in crypt epithelia, where V. fischeri induces morphogenesis. The data presented here provide a window into the evolution of LBPs and the scope of their roles in animal symbioses. Mammalian lipopolysaccharide (LPS)-binding protein (LBP) is implicated in conveying LPS to host cells and potentiating its signaling activity. In certain disease states, such as obesity, the overproduction of this protein has been a reliable biomarker of chronic inflammation. Here, we describe a symbiosis-induced invertebrate LBP whose tertiary structure and LPS-binding characteristics are similar to those of mammalian LBPs; however, the primary structure of this distantly related squid protein (EsLBP1) differs in key residues previously believed to be essential for LPS binding, suggesting that an alternative strategy exists. Surprisingly, symbiotic expression of eslbp1 is induced by peptidoglycan derivatives, not LPS, a pattern converse to that of RegIIIγ, an important mammalian immunity protein that binds peptidoglycan but whose gene expression is induced by LPS. Finally, EsLBP1 occurs along the apical surfaces of all the host’s epithelia, suggesting that it was recruited from a general defensive role to one that mediates specific interactions with its symbiont.
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Tang L, Liang Y, Jiang Y, Liu S, Zhang F, He X, Wang T, Zhou Y, Zhong H, Yan J. Identification and expression analysis on bactericidal permeability-increasing protein/lipopolysaccharide-binding protein of blunt snout bream, Megalobrama amblycephala. FISH & SHELLFISH IMMUNOLOGY 2015; 45:630-640. [PMID: 25982396 DOI: 10.1016/j.fsi.2015.05.013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 05/03/2015] [Accepted: 05/05/2015] [Indexed: 06/04/2023]
Abstract
Bactericidal permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) belong to the lipid transfer protein/lipopolysaccharide-binding protein family and play a critical role in the innate immune response to Gram-negative bacteria. In the present study, a novel BPI/LBP from blunt snout bream, Megalobrama amblycephala (maBPI/LBP) was isolated by RACE techniques. The open reading frame (ORF) of maBPI/LBP gene encoded a polypeptide of 474 amino acids with a putative 18-aa hydrophobic signal peptide. Structurally, the maBPI/LBP showed highly similar to those of BPI/LBPs from invertebrate and teleost, LBPs and BPIs from mammal, which contained an N-terminal BPI/LBP/CETP domain BPI1 with a LPS-binding domain, a C-terminal BPI/LBP/CETP domain BPI2, and proline-rich domain. The homologous identities of deduced amino acid sequences displayed that the maBPI/LBP possessed significant similarity (96.61% and 90.07%) with those of grass carp and common carp, respectively. The recombinant protein of maBPI/LBP showed effectively kill Gram-negative bacteria. The maBPI/LBP gene was expressed in a wide range of normal tested tissues, with the highest expression levels in the kidney. The experiments revealed that the mRNA expression of maBPI/LBP in spleen considerably up-regulated from 2 h to 8 h post LPS stimulation, and peaked rapidly at 2 h (7.40-fold, P < 0.05), which confirmed that maBPI/LBP was the absolute sensitive to LPS stimulation. Furthermore, the level of maBPI/LBP mRNA expression reached the maximum for a second time at 24 h after LPS stimulation. These results suggested that maBPI/LBP was a constitutive and inducible acute-phase protein contributing to the host immune defense against pathogenic bacterial infection in M. amblycephala. This study will further our understanding of the function of BPI/LBP and the molecular mechanism of innate immunity in teleost.
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Affiliation(s)
- Leilei Tang
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China
| | - Yinhua Liang
- Department of Operation, Xiangya Hospital, Central South University, Changsha 410008, PR China
| | - Yuhong Jiang
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China
| | - Shaojun Liu
- Key Laboratory of Protein Chemistry and Developmental Biology of the State Education Ministry of China, College of Life Sciences, Hunan Normal University, Changsha 410018, PR China
| | - Fuyun Zhang
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China
| | - Xia He
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China
| | - Tianyi Wang
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China
| | - Yi Zhou
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fishery Sciences, Nanning, Guangxi 530021, PR China
| | - Huan Zhong
- Guangxi Key Laboratory of Aquatic Genetic Breeding and Healthy Aquaculture, Guangxi Academy of Fishery Sciences, Nanning, Guangxi 530021, PR China
| | - Jinpeng Yan
- State Key Laboratory of Medical Genetics & School of Life Sciences, Central South University, Changsha 410017, PR China.
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Płóciennikowska A, Hromada-Judycka A, Borzęcka K, Kwiatkowska K. Co-operation of TLR4 and raft proteins in LPS-induced pro-inflammatory signaling. Cell Mol Life Sci 2014; 72:557-581. [PMID: 25332099 PMCID: PMC4293489 DOI: 10.1007/s00018-014-1762-5] [Citation(s) in RCA: 488] [Impact Index Per Article: 48.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Revised: 10/01/2014] [Accepted: 10/13/2014] [Indexed: 11/28/2022]
Abstract
Toll-like receptor 4 (TLR4) is activated by lipopolysaccharide (LPS), a component of Gram-negative bacteria to induce production of pro-inflammatory mediators aiming at eradication of the bacteria. Dysregulation of the host responses to LPS can lead to a systemic inflammatory condition named sepsis. In a typical scenario, activation of TLR4 is preceded by binding of LPS to CD14 protein anchored in cholesterol- and sphingolipid-rich microdomains of the plasma membrane called rafts. CD14 then transfers the LPS to the TLR4/MD-2 complex which dimerizes and triggers MyD88- and TRIF-dependent production of pro-inflammatory cytokines and type I interferons. The TRIF-dependent signaling is linked with endocytosis of the activated TLR4, which is controlled by CD14. In addition to CD14, other raft proteins like Lyn tyrosine kinase of the Src family, acid sphingomyelinase, CD44, Hsp70, and CD36 participate in the TLR4 signaling triggered by LPS and non-microbial endogenous ligands. In this review, we summarize the current state of the knowledge on the involvement of rafts in TLR4 signaling, with an emphasis on how the raft proteins regulate the TLR4 signaling pathways. CD14-bearing rafts, and possibly CD36-rich rafts, are believed to be preferred sites of the assembly of a multimolecular complex which mediates the endocytosis of activated TLR4.
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Affiliation(s)
- Agnieszka Płóciennikowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Aneta Hromada-Judycka
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Kinga Borzęcka
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology, 3 Pasteur St., 02-093, Warsaw, Poland.
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Fang L, Xu Z, Wang GS, Ji FY, Mei CX, Liu J, Wu GM. Directed evolution of an LBP/CD14 inhibitory peptide and its anti-endotoxin activity. PLoS One 2014; 9:e101406. [PMID: 25025695 PMCID: PMC4098906 DOI: 10.1371/journal.pone.0101406] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 06/06/2014] [Indexed: 11/23/2022] Open
Abstract
Background LPS-binding protein (LBP) and its ligand CD14 are located upstream of the signaling pathway for LPS-induced inflammation. Blocking LBP and CD14 binding might prevent LPS-induced inflammation. In previous studies, we obtained a peptide analog (MP12) for the LBP/CD14 binding site and showed that this peptide analog had anti-endotoxin activity. In this study, we used in vitro directed evolution for this peptide analog to improve its in vivo and in vitro anti-endotoxin activity. Methods We used error-prone PCR (ep-PCR) and induced mutations in the C-terminus of LBP and attached the PCR products to T7 phages to establish a mutant phage display library. The positive clones that competed with LBP for CD14 binding was obtained by screening. We used both in vivo and in vitro experiments to compare the anti-endotoxin activities of a polypeptide designated P1 contained in a positive clone and MP12. Results 11 positive clones were obtained from among target phages. Sequencing showed that 9 positive clones had a threonine (T) to methionine (M) mutation in amino acid 287 of LBP. Compared to polypeptide MP12, polypeptide P1 significantly inhibited LPS-induced TNF-α expression and NF-κB activity in U937 cells (P<0.05). Compared to MP12, P1 significantly improved arterial oxygen pressure, an oxygenation index, and lung pathology scores in LPS-induced ARDS rats (P<0.05). Conclusion By in vitro directed evolution of peptide analogs for the LBP/CD14 binding site, we established a new polypeptide (P1) with a threonine (T)-to-methionine (M) mutation in amino acid 287 of LBP. This polypeptide had high anti-endotoxin activity in vitro and in vivo, which suggested that amino acid 287 in the C-terminus of LBP may play an important role in LBP binding with CD14.
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Affiliation(s)
- Li Fang
- Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Zhi Xu
- Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Guan-song Wang
- Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Fu-yun Ji
- Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Chun-xia Mei
- Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Juan Liu
- Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Guo-ming Wu
- Institute of Respiratory Disease, Xinqiao Hospital, Third Military Medical University, Chongqing, China
- * E-mail:
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Ovocalyxin-36 is an effector protein modulating the production of proinflammatory mediators. Vet Immunol Immunopathol 2014; 160:1-11. [DOI: 10.1016/j.vetimm.2014.03.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2013] [Revised: 01/29/2014] [Accepted: 03/03/2014] [Indexed: 01/31/2023]
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A functional variant of lipopolysaccharide binding protein predisposes to sepsis and organ dysfunction in patients with major trauma. Ann Surg 2012; 255:147-57. [PMID: 22167001 DOI: 10.1097/sla.0b013e3182389515] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
OBJECTIVE To determine the hypothesis that genetic variations of the lipopolysaccharide-binding protein (LBP) gene influence risk for the development of sepsis and multiple organ dysfunction (MOD) in patients with major trauma. BACKGROUND Lipopolysaccharide-binding protein plays a central role in innate immune response as the first line of defense and directing the microbial-induced activation of the inflammatory host response. Although a total of 112 single nucleotide polymorphisms (SNPs) have been identified so far within the entire LBP gene, only a few SNPs have been studied. METHODS Nine haplotype tagging SNPs (htSNPs) were selected from 51 SNPs with a minor allele frequency of ≥5% using the HapMap database for the Chinese Han population. Two independent cohorts of major trauma patients were recruited. The 9 htSNPs were genotyped using pyrosequencing method and analyzed in relation to the risk of development of sepsis and MOD, LBP production, and lipopolysaccharide (LPS)-induced activation of peripheral blood leukocytes. Moreover, the functionality of the rs2232618 polymorphism was assessed by the observation of its effects on the binding and activation of LPS and the LBP-CD14 interaction. RESULTS Among the 9 htSNPs, only the rs2232618 was significantly associated with higher susceptibility to sepsis and MOD in the 2 independent cohorts of major trauma patients recruited from southwest and eastern China. This SNP was also significantly associated with LPS-induced activation of peripheral blood leukocytes. In addition, the rs2232618 polymorphism could enhance LBP protein activities, showing significant increases in LPS binding to macrophages, LPS-induced cellular activation, and LBP-CD14 interaction at the presence of the variant LBP protein. CONCLUSIONS The rs2232618 polymorphism is a functional SNP and confers host susceptibility to sepsis and multiple organ dysfunction in patients with major trauma.
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Abstract
CETP (cholesteryl ester-transfer protein) is essential for neutral lipid transfer between HDL (high-density lipoprotein) and LDL (low-density lipoprotein) and plays a critical role in the reverse cholesterol transfer pathway. In clinical trials, CETP inhibitors increase HDL levels and reduce LDL levels, and therefore may be used as a potential treatment for atherosclerosis. In this review, we cover the analysis of CETP structure and provide insights into CETP-mediated lipid transfer based on a collection of structural and biophysical data.
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Fornander L, Ghafouri B, Kihlström E, Åkerlind B, Schön T, Tagesson C, Lindahl M. Innate immunity proteins and a new truncated form of SPLUNC1 in nasopharyngeal aspirates from infants with respiratory syncytial virus infection. Proteomics Clin Appl 2011; 5:513-22. [DOI: 10.1002/prca.201100016] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 06/16/2011] [Accepted: 07/11/2011] [Indexed: 11/07/2022]
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Preparation and identification of the lipopolysaccharide binding protein mimic epitope peptide vaccine that prevents endotoxin-induced acute lung injury in mice. Vaccine 2011; 29:4162-72. [PMID: 21473948 DOI: 10.1016/j.vaccine.2011.03.056] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Revised: 02/12/2011] [Accepted: 03/17/2011] [Indexed: 11/22/2022]
Abstract
The objectives of this study were to detect the immunogenicity of a lipopolysaccharide (LPS) binding protein (LBP) mimic epitope peptide vaccine and evaluate its effect on controlling excessive and uncontrolled inflammatory reactions in mice with acute lung injury. The vaccine was prepared by mixing self-made LBP mimic epitope multiple antigen peptide (MAP) and Freund adjuvants in a proper proportion. Healthy mice were inoculated with the vaccine and the dynamic changes of anti-MAP antibody were measured using ELISA. Anti-MAP antibody was prepared from the immune serum of the mice based on the standard antibody preparation program. Western blot assay was used to identify LBP specificity of anti-MAP antibody. Anti-MAP antibody bioactivity was analyzed using in vitro binding activity test. Following the vaccine inoculation, the mice were injected with LPS to induce acute lung injury. Anti-MAP antibody prepared was also used to immune the mice with LPS-induced acute lung injury. TNF-α and IL-1β contents in serum and lung tissue homogenate were measured using double antibody sandwiched ELISA at different time-points after LPS challenge. At 8h time-point, total white blood cell counts, polymorphonuclear leucocyte count and protein content in bronchoalveolar lavage fluid were measured and pulmonary morphological changes were evaluated. The antibody titer was gradually rising, reaching to its peak at 8th week and lasting to the tenth week. The antibody possessed strong immunogenicity, high specificity and favorable biologic activity. Whole range inoculation of LBP mimic epitope peptide vaccine or anti-MAP antibody intervention partly eliminates LPS-mediated acute lung injury. In conclusion, LBP mimic epitope peptide vaccine successfully induced highly specific antibody with high bioactivity in mice. LBP mimic epitope peptide vaccine and anti-MAP antibody inhibited excessive and uncontrolled inflammatory reactions from LPS-mediated acute lung injury in mice.
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Vida A, Troelstra A, Antal-Szalmás P, van Bommel TJP, Verheul AFM, Verhoef J, van Kessel KPM, van Strijp JAG. Neutralization of Neisseria meningitidis outer membrane vesicles. Inflamm Res 2011; 60:801-5. [DOI: 10.1007/s00011-011-0344-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 04/13/2011] [Accepted: 05/04/2011] [Indexed: 11/28/2022] Open
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Zhang Y, He X, Li X, Fu D, Chen J, Yu Z. The second bactericidal permeability increasing protein (BPI) and its revelation of the gene duplication in the Pacific oyster, Crassostrea gigas. FISH & SHELLFISH IMMUNOLOGY 2011; 30:954-963. [PMID: 21300156 DOI: 10.1016/j.fsi.2011.01.031] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 01/28/2011] [Accepted: 01/30/2011] [Indexed: 05/30/2023]
Abstract
A novel homolog of BPI was cloned from the hemocyte cDNA of Crassostrea gigas and designed as Cg-BPI2, which share the highest sequence identity with the well-known Cg-BPI (designed as Cg-BPI1). The complete cDNA of Cg-BPI2 included an open reading frame (ORF) of 1440 bp, and 3' and 5' untranslated regions (UTR's) of 49 bp and 166 bp, respectively. The ORF encoded a putative protein of 479 amino acids with predicted 22-aa hydrophobic signal peptide. The phylogenetic analysis showed that one of the gene duplications could have resulted in the emergence of two homologs of BPI in oysters, which probably might have occurred after the gastropod-bivalve divergence. Furthermore, molecular modeling analysis showed that both Cg-BPIs are similar to a highly extended boomerang like shape of human BPI, consisting of an N- and C-terminal barrel and a central β-sheet. Comparison of the electrostatic surface potentials revealed that surfaces of Cg-BPI2 have more intense positive charge than that of human BPI and the Cg-BPI1. The recombinant N-terminal barrel domain showed a high affinity to LPS and can effectively kill Gram-negative bacteria. The mRNAs of two Cg-BPIs were observed in all tissues examined with the highest expression in gills. The mRNAs expression profiles in response to bacterial challenge revealed that they were inducible under infection, but with a distinct and complementary expression patterns between Cg-BPI1 and Cg-BPI2. Our findings of this second BPI gene demonstrated presence of its gene duplication for the first time in invertebrate and it appears to be one of effective LPS-binding AMPs in elimination of Gram-negative pathogens C. gigas.
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Affiliation(s)
- Yang Zhang
- Key Laboratory of Marine Bio-resource Sustainable Utilization, Laboratory of Applied Marine Biology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, PR China
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Gauthier MEA, Du Pasquier L, Degnan BM. The genome of the sponge Amphimedon queenslandica provides new perspectives into the origin of Toll-like and interleukin 1 receptor pathways. Evol Dev 2011; 12:519-33. [PMID: 20883219 DOI: 10.1111/j.1525-142x.2010.00436.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Members of the Toll-like receptor (TLR) and the interleukin 1 receptor (IL1R) superfamilies activate various signaling cascades that are evolutionarily conserved in eumetazoans. In this study, we have searched the genome and expressed sequence tags of the demosponge Amphimedon queenslandica for molecules involved in TLR and IL1R signaling. Although we did not identify a conventional TLR or ILR, the Amphimedon genome encodes two related receptors, AmqIgTIRs, which are comprised of at least three extracellular IL1R-like immunoglobulins (Ig) and an intracellular TLR-like Toll/interleukin1 receptor/resistance (TIR) domain. The remainder of the TLR/IL1R pathway is mostly conserved in Amphimedon and includes genes known to interact with TLRs and IL1Rs in bilaterians, such as Toll-interacting protein (Tollip) and myeloid differentiation factor 88 (MyD88). By comparing the sponge genome to that of nonmetazoan eukaryotes and other basal animal phyla (i.e., placozoan and cnidarian representatives) we can infer that most components of the signaling cascade, including the receptors, evolved after the divergence of metazoan, and choanoflagellate lineages. In most cases, these proteins are composed of metazoan-specific domains (e.g., Pellino) or architectures (e.g., the association of a death domain with a TIR domain in the MyD88). The dynamic expression of the two AmqIgTIRs, AmqMyD88, AmqTollip, and AmqPellino during Amphimedon embryogenesis and larval development is consistent with the TLR/IL1R pathway having a role in both development and immunity in the last common metazoan ancestor.
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Affiliation(s)
- Marie E A Gauthier
- School of Biological Sciences, University of Queensland, Brisbane, Qld 4072, Australia
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Ostuni R, Zanoni I, Granucci F. Deciphering the complexity of Toll-like receptor signaling. Cell Mol Life Sci 2010; 67:4109-34. [PMID: 20680392 PMCID: PMC11115668 DOI: 10.1007/s00018-010-0464-x] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2010] [Revised: 07/02/2010] [Accepted: 07/09/2010] [Indexed: 12/26/2022]
Abstract
Toll-like receptors (TLRs) are essential players in the innate immune response to invading pathogens. Although extensive research efforts have provided a considerable wealth of information on how TLRs function, substantial gaps in our knowledge still prevent the definition of a complete picture of TLR signaling. However, several recent studies describe additional layers of complexity in the regulation of TLR ligand recognition, adaptor recruitment, posttranslational modifications of signaling proteins, and the newly described, autonomous role of the TLR4 co-receptor CD14. In this review, by using it as model system for the whole TLR family, we attempt to provide a complete description of the signal transduction pathways triggered by TLR4, with a particular emphasis on the molecular and cell biological aspects regulating its function. Finally, we discuss a recently reported model of CD14-dependent signaling and highlight its biological implications.
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Affiliation(s)
- Renato Ostuni
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Ivan Zanoni
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
| | - Francesca Granucci
- Department of Biotechnology and Bioscience, University of Milano-Bicocca, Piazza della Scienza 2, 20126 Milan, Italy
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Piazza M, Colombo M, Zanoni I, Granucci F, Tortora P, Weiss J, Gioannini T, Prosperi D, Peri F. Uniform Lipopolysaccharide (LPS)-Loaded Magnetic Nanoparticles for the Investigation of LPS-TLR4 Signaling. Angew Chem Int Ed Engl 2010. [DOI: 10.1002/ange.201004655] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Piazza M, Colombo M, Zanoni I, Granucci F, Tortora P, Weiss J, Gioannini T, Prosperi D, Peri F. Uniform lipopolysaccharide (LPS)-loaded magnetic nanoparticles for the investigation of LPS-TLR4 signaling. Angew Chem Int Ed Engl 2010; 50:622-6. [PMID: 21226138 DOI: 10.1002/anie.201004655] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Indexed: 12/11/2022]
Affiliation(s)
- Matteo Piazza
- Dipartimento di Biotecnologie e Bioscienze, Università di Milano Bicocca, Piazza della Scienza 2, 20126 Milano, Italy
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Feng YK, Yang QH, Liu YS, Xu JC, Qian GS, Wang YH. The localization of two mimic epitopes of lipopolysaccharide binding protein and the preparation of their tandem multiple antigen peptide. J Immunol Methods 2010; 362:60-9. [DOI: 10.1016/j.jim.2010.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2010] [Revised: 08/20/2010] [Accepted: 09/01/2010] [Indexed: 10/19/2022]
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Prohinar P, Rallabhandi P, Weiss JP, Gioannini TL. Expression of functional D299G.T399I polymorphic variant of TLR4 depends more on coexpression of MD-2 than does wild-type TLR4. THE JOURNAL OF IMMUNOLOGY 2010; 184:4362-7. [PMID: 20212095 DOI: 10.4049/jimmunol.0903142] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Two missense variants (D299G and T399I) of TLR4 are cosegregated in individuals of European descent and, in a number of test systems, result in reduced responsiveness to endotoxin. How these changes within the ectodomain (ecd) of TLR4 affect TLR4 function is unclear. For both wild-type and D299G.T399I TLR4, we used endotoxinCD14 and endotoxinMD-2 complexes of high specific radioactivity to measure: 1) interaction of recombinant MD-2TLR4 with endotoxinCD14 and TLR4 with endotoxinMD-2; 2) expression of functional MD-2TLR4 and TLR4; and 3) MD-2TLR4 and TLR4-dependent cellular endotoxin responsiveness. Both wild-type and D299G.T399I TLR4(ecd) demonstrated high affinity (K(d) approximately 200 pM) interaction of endotoxinCD14 with MD-2TLR4(ecd) and endotoxinMD-2 with TLR4(ecd). However, levels of functional TLR4 were reduced up to 2-fold when D299G.T399I TLR4 was coexpressed with MD-2 and >10-fold when expressed without MD-2, paralleling differences in cellular endotoxin responsiveness. The dramatic effect of the D299G.T399I haplotype on expression of functional TLR4 without MD-2 suggests that cells expressing TLR4 without MD-2 are most affected by these polymorphisms.
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Affiliation(s)
- Polonca Prohinar
- Department of Internal Medicine, Roy A and Lucille J Carver College of Medicine, University of Iowa, Iowa City, IA 52240, USA
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Canny G, Levy O. Bactericidal/permeability-increasing protein (BPI) and BPI homologs at mucosal sites. Trends Immunol 2009; 29:541-7. [PMID: 18838299 DOI: 10.1016/j.it.2008.07.012] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 07/24/2008] [Accepted: 07/28/2008] [Indexed: 12/19/2022]
Abstract
At mucosal surfaces, we must co-exist with a high density of diverse microorganisms; therefore, protection against these occurs on multiple levels. Leukocyte- and epithelial derived-antimicrobial peptides and proteins (AMPs) comprise an essential component of immune defense. These molecules possess antibacterial, antifungal and signalling properties and probably contribute to defence and maintenance of homeostasis between the host and commensal microorganisms. Among these AMPs is bactericidal/permeability-increasing protein (BPI), an antimicrobial protein with potent endotoxin-neutralising activity, and several homologs. This review explores the roles of BPI and and its homologs at the mucosal interface. Congeners of BPI are under biopharmaceutical development as novel anti-infective agents, highlighting the potential therapeutic relevance of this protein family.
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Affiliation(s)
- Geraldine Canny
- Department of Gynecology, Obstetrics and Medical Genetics, Central University Hospital of Vaud (CHUV), 1011 Lausanne, Switzerland.
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Yermak IM, Davydova VN. Interaction of bacterial lipopolysaccharides with host soluble proteins and polycations. BIOCHEMISTRY MOSCOW SUPPLEMENT SERIES A-MEMBRANE AND CELL BIOLOGY 2008. [DOI: 10.1134/s1990747808040016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Jin MS, Lee JO. Structures of the toll-like receptor family and its ligand complexes. Immunity 2008; 29:182-91. [PMID: 18701082 DOI: 10.1016/j.immuni.2008.07.007] [Citation(s) in RCA: 390] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Indexed: 11/30/2022]
Abstract
Toll-like receptors (TLRs) play central roles in the innate immune response by recognizing conserved structural patterns in diverse microbial molecules. Here, we discuss ligand binding and activation mechanisms of the TLR family. Hydrophobic ligands of TLR1, TLR2, and TLR4 interact with internal protein pockets. In contrast, dsRNA, a hydrophilic ligand, interacts with the solvent-exposed surface of TLR3. Binding of agonistic ligands, lipopeptides or dsRNA, induces dimerization of the ectodomains of the various TLRs, forming dimers that are strikingly similar in shape. In these "m"-shaped complexes, the C termini of the extracellular domains of the TLRs converge in the middle. This observation suggests the hypothesis that dimerization of the extracellular domains forces the intracellular TIR domains to dimerize, and this initiates signaling by recruiting intracellular adaptor proteins.
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Affiliation(s)
- Mi Sun Jin
- Department of Chemistry and Institute for the BioCentury, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Daejeon, 305-701, Korea
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Satoh M, Ando S, Shinoda T, Yamazaki M. Clearance of bacterial lipopolysaccharides and lipid A by the liver and the role of argininosuccinate synthase. Innate Immun 2008; 14:51-60. [PMID: 18387919 DOI: 10.1177/1753425907087267] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
The liver is thought to be involved in the systemic clearance and detoxification of lipopolysaccharide (LPS). Argininosuccinate synthase (AS), a liver cytosolic urea cycle enzyme, has been found to bind to and inactivate LPS and lipid A. To elucidate the participation of AS in the clearance of LPS by liver and hepatocytes, we investigated the correlation between AS content and the removal of lipid A and LPS in vivo and in vitro, tracing levels of biological activity. A hepatotoxic model in which mice were injected with CCl(4) revealed a significant reduction in lipid A clearance along with liver failure on day 1; total body clearance was changed to 0.534 ml/min from 1.42 ml/min. AS content in liver concomitantly decreased to about half and AS leaked to blood at about 6 microg/ml. Total body clearance of i.v. injected AS was estimated at 0.083 ml/min, which predicted about 24-h leakage of AS after CCl(4) injection. The treatment also reduced the clearance of R-type LPSs to a lesser degree the larger its polysaccharide portion. S-type LPS, which has a large O-antigen polysaccharide, exhibited enhancement of clearance on CCl(4) treatment. When pretreated in vitro with AS and injected into normal mice, lipid A and R-type LPS showed a similar pattern of clearance of residual activities to the untreated forms, but S-type LPS exhibited enhancement of clearance. Comparison between different strains of mice revealed a correlation of AS content in liver and lipid A clearance, where the higher AS strain C3H/He mice showed a more rapid clearance than the lower AS strains C57BL/6 and BALB/c. Primary spheroid cultures of hepatocytes treated with 0.1 microM dexamethasone and 1 microM glucagon showed about a 2-fold increase in AS amount and a more rapid clearance of LPS from culture medium than untreated cells. These results suggest that AS in hepatocytes may be involved in the process of lipid A and LPS clearance and the extracellular leakage of AS may also participate in the systemic detoxification.
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Affiliation(s)
- Motonobu Satoh
- Department of Medicinal Chemistry, Faculty of Pharmaceutical Sciences, Teikyo University, Sagamihara, Kanagawa, Japan.
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Wittmann I, Schönefeld M, Aichele D, Groer G, Gessner A, Schnare M. Murine Bactericidal/Permeability-Increasing Protein Inhibits the Endotoxic Activity of Lipopolysaccharide and Gram-Negative Bacteria. THE JOURNAL OF IMMUNOLOGY 2008; 180:7546-52. [DOI: 10.4049/jimmunol.180.11.7546] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Teghanemt A, Prohinar P, Gioannini TL, Weiss JP. Transfer of monomeric endotoxin from MD-2 to CD14: characterization and functional consequences. J Biol Chem 2007; 282:36250-6. [PMID: 17934216 DOI: 10.1074/jbc.m705995200] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Potent Toll-like receptor 4 (TLR4)-dependent cell activation by endotoxin depends on sequential transfer of monomers of endotoxin from an aggregated form to CD14 via the lipopolysaccharide-binding protein and then to MD-2. We now show that monomeric endotoxin can be transferred in reverse from MD-2 to CD14 but not to lipopolysaccharide-binding protein. Reverse transfer requires an approximately 1000-fold molar excess of CD14 to endotoxin-MD-2. Transfer of endotoxin from MD-2 to extracellular soluble CD14 reduces activation of cells expressing TLR4 without MD-2. However, transfer of endotoxin from MD-2 to membrane CD14 (mCD14) makes cells expressing MD-2.TLR4 sensitive to activation by the endotoxin-MD-2 complex. An endotoxin-mutant (F126A) MD-2 complex that does not activate cells expressing TLR4 alone potently activates cells expressing mCD14, MD-2, and TLR4 by transferring endotoxin to mCD14, which then transfers endotoxin to endogenous wild-type MD-2.TLR4. These findings describe a novel pathway of endotoxin transfer that provides an additional layer of regulation of cell activation by endotoxin.
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Affiliation(s)
- Athmane Teghanemt
- Department of Internal Medicine and the Inflammation Program, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City 52242, USA
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Schultz H, Hume J, Zhang DS, Gioannini TL, Weiss JP. A Novel Role for the Bactericidal/Permeability Increasing Protein in Interactions of Gram-Negative Bacterial Outer Membrane Blebs with Dendritic Cells. THE JOURNAL OF IMMUNOLOGY 2007; 179:2477-84. [PMID: 17675509 DOI: 10.4049/jimmunol.179.4.2477] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The bactericidal/permeability-increasing protein (BPI) is thought to play an important role in killing and clearance of Gram-negative bacteria and the neutralization of endotoxin. A possible role for BPI in clearance of cell-free endotoxin has also been suggested based on studies with purified endotoxin aggregates and blood monocytes. Because the interaction of BPI with cell-free endotoxin, during infection, occurs mainly in tissue and most likely in the form of shed bacterial outer membrane vesicles ("blebs"), we examined the effect of BPI on interactions of metabolically labeled ([(14)C]-acetate) blebs purified from Neisseria meningitidis serogroup B with either human monocyte-derived macrophages or monocyte-derived dendritic cells (MDDC). BPI produced a dose-dependent increase (up to 3-fold) in delivery of (14)C-labeled blebs to MDDC, but not to monocyte-derived macrophages in the presence or absence of serum. Both, fluorescently labeled blebs and BPI were internalized by MDDC under these conditions. The closely related LPS-binding protein, in contrast to BPI, did not increase association of the blebs with MDDC. BPI-enhanced delivery of the blebs to MDDC did not increase cell activation but permitted CD14-dependent signaling by the blebs as measured by changes in MDDC morphology, surface expression of CD80, CD83, CD86, and MHC class II and secretion of IL-8, RANTES, and IP-10. These findings suggest a novel role of BPI in the interaction of bacterial outer membrane vesicles with dendritic cells that may help link innate immune recognition of endotoxin to Ag delivery and presentation.
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Affiliation(s)
- Hendrik Schultz
- Inflammation Program, University of Iowa and Iowa City Veterans Affairs Medical Center, IA, USA
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Solstad T, Stenvik J, Jørgensen TØ. mRNA expression patterns of the BPI/LBP molecule in the Atlantic cod (Gadus morhua L.). FISH & SHELLFISH IMMUNOLOGY 2007; 23:260-71. [PMID: 17442589 DOI: 10.1016/j.fsi.2006.10.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2006] [Revised: 09/27/2006] [Accepted: 10/03/2006] [Indexed: 05/14/2023]
Abstract
Bactericidal/permeability-increasing protein (BPI) and lipopolysaccharide-binding protein (LBP) are important components of the mammalian innate defence system against Gram-negative infections. cDNA encoding a protein related to mammalian BPI and LBP have been cloned from several teleosts including the Atlantic cod (Gadus morhua L.). Using real-time PCR an increase in cod BPI/LBP expression in whole blood and peritoneal cells was demonstrated one, two and four days after intraperitoneal injection of inactivated Vibrio anguillarum. Although constitutively produced in the head kidney, a moderate rise of BPI/LBP mRNA production was seen on day two in this organ. After seven days the BPI/LBP mRNA levels at the three locations examined were almost back to normal. In situ hybridisation demonstrated a leucocytic localisation and morphology of the BPI/LBP expressing cells in various tissues. A combination of in situ hybridisation and peroxidase staining of head kidney leucocytes showed that the BPI/LBP producing cells are peroxidase positive and possible neutrophil like cells. The results suggest that the cod BPI/LBP is important in the first-line defence against bacterial infections and has a function more related to the mammalian BPI molecule than the LBP counterpart.
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Affiliation(s)
- Terese Solstad
- Department of Marine Biotechnology, The Norwegian College of Fishery Science, University of Tromsø, N-9037 Tromsø, Norway.
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Schultz H, Weiss JP. The bactericidal/permeability-increasing protein (BPI) in infection and inflammatory disease. Clin Chim Acta 2007; 384:12-23. [PMID: 17678885 PMCID: PMC2695927 DOI: 10.1016/j.cca.2007.07.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2007] [Revised: 05/23/2007] [Accepted: 07/03/2007] [Indexed: 11/28/2022]
Abstract
Gram-negative bacteria (GNB) and their endotoxin present a constant environmental challenge. Endotoxins can potently signal mobilization of host defenses against invading GNB but also potentially induce severe pathophysiology, necessitating controlled initiation and resolution of endotoxin-induced inflammation to maintain host integrity. The bactericidal/permeability-increasing protein (BPI) is a pluripotent protein expressed, in humans, mainly neutrophils. BPI exhibits strong antimicrobial activity against GNB and potent endotoxin-neutralizing activity. BPI mobilized with neutrophils in response to invading GNB can promote intracellular and extracellular bacterial killing, endotoxin neutralization and clearance, and delivery of GNB outer membrane antigens to dendritic cells. Tissue expression by dermal fibroblasts and epithelia could further amplify local levels of BPI and local interaction with GNB and endotoxin, helping to constrain local tissue infection and inflammation and prevent systemic infection and systemic inflammation. This review article focuses on the structural and functional properties of BPI with respect to its contribution to host defense during GNB infections and endotoxin-induced inflammation and the genesis of autoantibodies against BPI that can blunt BPI activity and potentially contribute to chronic inflammatory disease.
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Affiliation(s)
- Hendrik Schultz
- Division of Infectious Diseases, University of Iowa, and Iowa City VAMC, USA, Iowa City, Iowa 52242, USA.
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