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Matveichuk OV, Ciesielska A, Hromada-Judycka A, Nowak N, Ben Amor I, Traczyk G, Kwiatkowska K. Flotillins affect LPS-induced TLR4 signaling by modulating the trafficking and abundance of CD14. Cell Mol Life Sci 2024; 81:191. [PMID: 38652315 PMCID: PMC11039508 DOI: 10.1007/s00018-024-05221-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 03/01/2024] [Accepted: 03/28/2024] [Indexed: 04/25/2024]
Abstract
Lipopolysaccharide (LPS) induces a strong pro-inflammatory reaction of macrophages upon activation of Toll-like receptor 4 (TLR4) with the assistance of CD14 protein. Considering a key role of plasma membrane rafts in CD14 and TLR4 activity and the significant impact exerted on that activity by endocytosis and intracellular trafficking of the both LPS acceptors, it seemed likely that the pro-inflammatory reaction could be modulated by flotillins. Flotillin-1 and -2 are scaffolding proteins associated with the plasma membrane and also with endo-membranes, affecting both the plasma membrane dynamics and intracellular protein trafficking. To verify the above hypothesis, a set of shRNA was used to down-regulate flotillin-2 in Raw264 cells, which were found to also become deficient in flotillin-1. The flotillin deficiency inhibited strongly the TRIF-dependent endosomal signaling of LPS-activated TLR4, and to a lower extent also the MyD88-dependent one, without affecting the cellular level of TLR4. The flotillin depletion also inhibited the pro-inflammatory activity of TLR2/TLR1 and TLR2/TLR6 but not TLR3. In agreement with those effects, the depletion of flotillins down-regulated the CD14 mRNA level and the cellular content of CD14 protein, and also inhibited constitutive CD14 endocytosis thereby facilitating its shedding. Ultimately, the cell-surface level of CD14 was markedly diminished. Concomitantly, CD14 recycling was enhanced via EEA1-positive early endosomes and golgin-97-positive trans-Golgi network, likely to compensate for the depletion of the cell-surface CD14. We propose that the paucity of surface CD14 is the reason for the down-regulated signaling of TLR4 and the other TLRs depending on CD14 for ligand binding.
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Affiliation(s)
- Orest V Matveichuk
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Anna Ciesielska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093, Warsaw, Poland.
| | - Aneta Hromada-Judycka
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Natalia Nowak
- Laboratory of Imaging Tissue Structure and Function, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Ichrak Ben Amor
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Gabriela Traczyk
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093, Warsaw, Poland
| | - Katarzyna Kwiatkowska
- Laboratory of Molecular Membrane Biology, Nencki Institute of Experimental Biology PAS, 3 Pasteur St., 02-093, Warsaw, Poland.
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Quintana JI, Delgado S, Rábano M, Azkargorta M, Florencio-Zabaleta M, Unione L, Vivanco MDM, Elortza F, Jiménez-Barbero J, Ardá A. The impact of glycosylation on the structure, function, and interactions of CD14. Glycobiology 2024; 34:cwae002. [PMID: 38227775 PMCID: PMC10987292 DOI: 10.1093/glycob/cwae002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 12/21/2023] [Accepted: 12/30/2023] [Indexed: 01/18/2024] Open
Abstract
CD14 is an innate immune receptor that senses pathogen-associated molecular patterns, such as lipopolysaccharide, to activate the innate immune response. Although CD14 is known to be glycosylated, detailed understanding about the structural and functional significance of this modification is still missing. Herein, an NMR and MS-based study, assisted by MD simulations, has provided a 3D-structural model of glycosylated CD14. Our results reveal the existence of a key N-glycosylation site at Asn282 that exclusively contains unprocessed oligomannnose N-glycans that perfectly fit the concave cavity of the bent-solenoid shaped protein. This site is not accessible to glycosidases and is fundamental for protein folding and secretion. A second N-site at Asn151 displays mostly complex N-glycans, with the typical terminal epitopes of the host cell-line expression system (i.e. βGal, α2,3 and α2,6 sialylated βGal, here), but also particularities, such as the lack of core fucosylation. The glycan at this site points outside the protein surface, resulting in N-glycoforms fully exposed and available for interactions with lectins. In fact, NMR experiments show that galectin-4, proposed as a binder of CD14 on monocytes to induce their differentiation into macrophages-like cells, interacts in vitro with CD14 through the recognition of the terminal glycoepitopes on Asn151. This work provides key information about CD14 glycosylation, which helps to better understand its functional roles and significance. Although protein glycosylation is known to be dynamic and influenced by many factors, some of the features found herein (presence of unprocessed N-glycans and lack of core Fuc) are likely to be protein specific.
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Affiliation(s)
- Jon Imanol Quintana
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
| | - Sandra Delgado
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
| | - Miriam Rábano
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
| | - Mikel Azkargorta
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
| | - Mirane Florencio-Zabaleta
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
| | - Luca Unione
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
- Ikerbasque, Basque Foundation for Science, Euskadi Plaza 5, 48009, Bilbao, Spain
| | - Maria dM Vivanco
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
| | - Félix Elortza
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
| | - Jesús Jiménez-Barbero
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
- Ikerbasque, Basque Foundation for Science, Euskadi Plaza 5, 48009, Bilbao, Spain
- Department of Organic & Inorganic Chemistry, Faculty of Science and Technology, University of the Basque Country, EHU-UPV, Leioa, Bizkaia 48940, Spain
- Centro de Investigacion Biomedica En Red de Enfermedades Respiratorias, Carlos III Health Institute, C. de Melchor Fernández Almagro, 3, Fuencarral-El Pardo, Madrid 28029, Spain
| | - Ana Ardá
- Center for Cooperative Research in Biosciences (CIC bioGUNE), Basque Research and Technology Alliance (BRTA), Bizkaia Science and Technology Park bld 800, Derio, Bizkaia 48160, Spain
- Ikerbasque, Basque Foundation for Science, Euskadi Plaza 5, 48009, Bilbao, Spain
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3
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Zhang NZ, Zhao LF, Zhang Q, Fang H, Song WL, Li WZ, Ge YS, Gao P. Core fucosylation and its roles in gastrointestinal glycoimmunology. World J Gastrointest Oncol 2023; 15:1119-1134. [PMID: 37546555 PMCID: PMC10401475 DOI: 10.4251/wjgo.v15.i7.1119] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/28/2023] [Accepted: 05/08/2023] [Indexed: 07/12/2023] Open
Abstract
Glycosylation is a common post-translational modification in eukaryotic cells. It is involved in the production of many biologically active glycoproteins and the regulation of protein structure and function. Core fucosylation plays a vital role in the immune response. Most immune system molecules are core fucosylated glycoproteins such as complements, cluster differentiation antigens, immunoglobulins, cytokines, major histocompatibility complex molecules, adhesion molecules, and immune molecule synthesis-related transcription factors. These core fucosylated glycoproteins play important roles in antigen recognition and clearance, cell adhesion, lymphocyte activation, apoptosis, signal transduction, and endocytosis. Core fucosylation is dominated by fucosyltransferase 8 (Fut8), which catalyzes the addition of α-1,6-fucose to the innermost GlcNAc residue of N-glycans. Fut8 is involved in humoral, cellular, and mucosal immunity. Tumor immunology is associated with aberrant core fucosylation. Here, we summarize the roles and potential modulatory mechanisms of Fut8 in various immune processes of the gastrointestinal system.
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Affiliation(s)
- Nian-Zhu Zhang
- Clinical Laboratory, The Second Hospital of Dalian Medical University, Dalian 116023, Liaoning Province, China
| | - Li-Fen Zhao
- Clinical Laboratory, The Second Hospital of Dalian Medical University, Dalian 116023, Liaoning Province, China
| | - Qian Zhang
- Department of Cell Therapy, Shanghai Tianze Yuntai Biomedical Co., Ltd., Shanghai 200100, China
| | - Hui Fang
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba 305-0005, Ibaraki, Japan
| | - Wan-Li Song
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Wen-Zhe Li
- Guangdong Provincial Key Laboratory of Infectious Diseases and Molecular Immunopathology, Shantou University Medical College, Shantou 515041, Guangdong Province, China
| | - Yu-Song Ge
- Department of Neurology, The Second Hospital of Dalian Medical University, Dalian 116023, Liaoning Province, China
| | - Peng Gao
- Clinical Laboratory, The Second Hospital of Dalian Medical University, Dalian 116023, Liaoning Province, China
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Sharygin D, Koniaris LG, Wells C, Zimmers TA, Hamidi T. Role of CD14 in human disease. Immunology 2023; 169:260-270. [PMID: 36840585 PMCID: PMC10591340 DOI: 10.1111/imm.13634] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Accepted: 02/21/2023] [Indexed: 02/26/2023] Open
Abstract
The cell surface antigen CD14 is primarily understood to act as a co-receptor for toll-like receptors (TLRs) to activate innate immunity responses to pathogens and tissue injury in macrophages and monocytes. However, roles for CD14 are increasingly being uncovered in disease responses in epithelial and endothelial cells. Consistent with these broader functions, CD14 expression is altered in a variety of non-immune cell types in response to a several of disease states. Moreover, soluble CD14 activated by factors from both pathogens and tissue damage may initiate signalling in a variety of non-immune cells. This review examined the current understanding CD14 in innate immunity as well as its potential functions in nonimmune cells and associated human diseases.
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Affiliation(s)
- Daniel Sharygin
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Chemistry, Massachusetts institute of technology, Cambridge, MA, USA
| | - Leonidas G. Koniaris
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Clark Wells
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Teresa A. Zimmers
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN, USA
- Department of Anatomy, Cell Biology and Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
- Center for Computational Biology and Bioinformatics, Indiana University School of Medicine, Indianapolis, IN, USA
- Richard L. Roudebush Veterans Administration Medical Center, Indianapolis, IN, USA
| | - Tewfik Hamidi
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
- Indiana University Simon Comprehensive Cancer Center, Indianapolis, IN, USA
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA
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5
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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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6
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Rawat K, Pal A, Banerjee S, Pal A, Mandal SC, Batabyal S. Ovine CD14- an Immune Response Gene Has a Role Against Gastrointestinal Nematode Haemonchus contortus-A Novel Report. Front Immunol 2021; 12:664877. [PMID: 34335567 PMCID: PMC8324245 DOI: 10.3389/fimmu.2021.664877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Accepted: 04/28/2021] [Indexed: 12/12/2022] Open
Abstract
CD14 (also known as the monocyte differentiation antigen) is an important immune response gene known to be primarily responsible for innate immunity against bacterial pathogens, and as a pattern recognition receptor (PRR), binds with LPS (endotoxin), lipoproteins, and lipotechoic acid of bacteria. So far very limited work has been conducted in parasitic immunology. In the current study, we reported the role of CD14 in parasitic immunology in livestock species (sheep) for the first time. Ovine CD14 is characterized as a horse-shoe shaped bent solenoid with a hydrophobic amino-terminal pocket for CD14 along with domains. High mutation frequency was observed, out of total 41 mutations identified, 23 mutations were observed to be thermodynamically unstable and 11 mutations were deleterious in nature, causing major functional alteration of important domains of CD14, an indication of variations in individual susceptibility for sheep against Haemonchus contortus infestations. In silico studies with molecular docking reveal a role of immune response against Haemonchus contortus in sheep, which is later confirmed with experimental evidence through differential mRNA expression analysis for sheep, which revealed better expression of CD14 in Haemonchus contortus infected sheep compared to that of non-infected sheep. We confirmed the above findings with supportive evidence through haematological and biochemical analyses. Phylogenetic analysis was conducted to assess the evolutionary relationship with respect to humans and it was observed that sheep may well be used as model organisms due to better genetic closeness compared to that of mice.
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Affiliation(s)
- Kavita Rawat
- Department of BioChemistry, West Bengal University of Animal and Fishery Sciences, Kolkata, India
| | - Aruna Pal
- Department of LFC, West Bengal University of Animal and Fishery Sciences, Kolkata, India
| | - Samiddha Banerjee
- Department of Animal Science, Visva Bharati University, Bolpur, India
| | - Abantika Pal
- Department of Computer Science, Indian Institute of Technology, Kharagpur, India
| | - Subhas Chandra Mandal
- Department of Parasitology, West Bengal University of Animal and Fishery Sciences, Kolkata, India
| | - Subhasis Batabyal
- Department of BioChemistry, West Bengal University of Animal and Fishery Sciences, Kolkata, India
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Holdbrooks AT, Ankenbauer KE, Hwang J, Bellis SL. Regulation of inflammatory signaling by the ST6Gal-I sialyltransferase. PLoS One 2020; 15:e0241850. [PMID: 33166339 PMCID: PMC7652342 DOI: 10.1371/journal.pone.0241850] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 10/21/2020] [Indexed: 12/31/2022] Open
Abstract
The ST6Gal-I sialyltransferase, an enzyme that adds α2-6-linked sialic acids to N-glycosylated proteins, regulates multiple immunological processes. However, the contribution of receptor sialylation to inflammatory signaling has been under-investigated. In the current study, we uncovered a role for ST6Gal-I in promoting sustained signaling through two prominent inflammatory pathways, NFκB and JAK/STAT. Using the U937 monocytic cell model, we determined that knockdown (KD) of ST6Gal-I expression had no effect on the rapid activation of NFκB by TNF (≤ 30 min), whereas long-term TNF-induced NFκB activation (2–6 hr) was diminished in ST6Gal-I-KD cells. These data align with prior work in epithelial cells showing that α2–6 sialylation of TNFR1 prolongs TNF-dependent NFκB activation. Similar to TNF, long-term, but not short-term, LPS-induced activation of NFκB was suppressed by ST6Gal-I KD. ST6Gal-I KD cells also exhibited reduced long-term IRF3 and STAT3 activation by LPS. Given that ST6Gal-I activity modulated LPS-dependent signaling, we conducted pull-down assays using SNA (a lectin specific for α2–6 sialic acids) to show that the LPS receptor, TLR4, is a substrate for sialylation by ST6Gal-I. We next assessed signaling by IFNγ, IL-6 and GM-CSF, and found that ST6Gal-I-KD had a limited effect on STAT activation induced by these cytokines. To corroborate these findings, signaling was monitored in bone marrow derived macrophages (BMDMs) from mice with myeloid-specific deletion of ST6Gal-I (LysMCre/ST6Gal-Ifl/fl). In agreement with data from U937 cells, BMDMs with ST6Gal-I knockout displayed reduced long-term activation of NFκB by both TNF and LPS, and diminished long-term LPS-dependent STAT3 activation. However, STAT activation induced by IFNγ, IL-6 and GM-CSF was comparable in wild-type and ST6Gal-I knockout BMDMs. These results implicate ST6Gal-I-mediated receptor sialylation in prolonging the activity of select signaling cascades including TNF/NFκB, LPS/NFκB, and LPS/STAT3, providing new insights into ST6Gal-I’s role in modulating the inflammatory phenotype of monocytic cells.
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Affiliation(s)
- Andrew T Holdbrooks
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Katherine E Ankenbauer
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Jihye Hwang
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America
| | - Susan L Bellis
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL, United States of America
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8
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Tian B, Tang D, Wu J, Liang M, Hao D, Wei Q. Molecular characterization, expression pattern and evolution of nine suppressors of cytokine signaling (SOCS) gene in the swamp eel (Monopterus albus). FISH & SHELLFISH IMMUNOLOGY 2020; 96:177-189. [PMID: 31811887 DOI: 10.1016/j.fsi.2019.11.022] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2019] [Revised: 11/06/2019] [Accepted: 11/09/2019] [Indexed: 06/10/2023]
Abstract
Suppressors of cytokine signaling (SOCS) family members have negative effects on cytokine signaling pathways involved in immunity, growth and development. Owing to their typical feature, they have been extensively studied in mammalians, but they have not offered systematic studies among teleosts. In the present study, nine SOCS family genes were identified in the swamp eel genome and analyzed regulation mechanisms of SOCS family members in swamp eels. The open reading frames of MaSOCS1a, MaSOCS1b, MaSOCS2, MaSOCS3a, MaSOCS3b, MaSOCS4, MaSOCS5, MaSOCS6 and MaSOCS7 were 663 bp, 603 bp, 717 bp, 618 bp, 645 bp, 1188 bp, 1488 bp, 1611 bp and 1998 bp and encoded 220, 238, 200, 205, 214, 395, 496, 536 and 655 amino acids, respectively. All SOCS proteins have no signal peptides. Multiple alignment revealed that MaSOCS family members possessed a typical conserved SOCS box and SH2 region. Phylogenetic analyses showed that all SOCS proteins were divided into two main clusters. Taken together with the similarity and identity of SOCS protein amino acids, these results indicated that MaSOCS family members shared conserved with other homologous genes, in which MaSOCS7 was more conserved. Further syntenic analysis confirmed the phylogenetic analysis results and annotation of SOCS protein, suggesting that MaSOCS5 shared a common ancestor gene with that of fish and humans. MaSOCS family members were constitutively expressed in a wide range of tissues with different levels. In particular, spleen and head kidneys play an important role in immune-related pathways. After Aeromonas veronii and polyinosinic-polycytidylic acid (poly I:C) challenge in the spleen and head kidney, MaSOCS family members exhibit different expression profiles. These expression patterns indicated that MaSOCS family members could make acute responses after pathogen invasion. Taken together, these results indicate that MaSOCS family members participate in the immune response against pathogens and offer a solid foundation for future studies of SOCS function.
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Affiliation(s)
- Bo Tian
- School of Animal Science, Yangtze University, Jingzhou, 434020, China; Engineering Research Centre of Ecology and Agricultural Use of Wetland, Ministry of Education, Jingzhou, 434020, China; Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture of China, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China
| | - Dongdong Tang
- School of Animal Science, Yangtze University, Jingzhou, 434020, China; Engineering Research Centre of Ecology and Agricultural Use of Wetland, Ministry of Education, Jingzhou, 434020, China
| | - Jinming Wu
- Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture of China, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China
| | - Meng Liang
- Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture of China, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China
| | - Du Hao
- Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture of China, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China
| | - Qiwei Wei
- Key Laboratory of Freshwater Biodiversity Conservation, Ministry of Agriculture of China, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China.
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9
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Gao W, Li S, Xu Q, Zhu D, Zhang Q, Luo K, Zhang W. Molecular characterization and expression analysis of Asian swamp eel (Monopterus albus) CXC chemokine receptor (CXCR) 1a, CXCR1b, CXCR2, CXCR3a, CXCR3b, and CXCR4 after bacteria and poly I:C challenge. FISH & SHELLFISH IMMUNOLOGY 2019; 84:572-586. [PMID: 30359750 DOI: 10.1016/j.fsi.2018.10.055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/13/2018] [Accepted: 10/22/2018] [Indexed: 06/08/2023]
Abstract
The CXC chemokine receptors (CXCRs) play critical roles in innate and adaptive immune systems. In this study, six Asian swamp eel (Monopterus albus) CXCRs (MaCXCR1-4) were identified and their molecular characterization and expression patterns were analyzed. The open reading frames (ORFs) of MaCXCR1a, MaCXCR1b, MaCXCR2, MaCXCR3a, MaCXCR3b, and MaCXCR4 were 1074 bp (base pairs), 1080 bp, 1125 bp, 1146 bp, 1083 bp, and 1140 bp, and encoded proteins of 357 aa (amino acids), 359 aa, 374 aa, 381 aa, 360 aa, and 379 aa, respectively. All these CXCRs have seven conserved transmembrane domains and four cysteines (with the exception of MaCXCR3b). Multiple sequence alignment revealed that the MaCXCRs possess a typical G-protein receptor family 1 signature and a DRY motif. There are also one to four potential N-glycosylation sites in the extracellular regions of the MaCXCRs, mainly distributed in the N-terminus and extracellular hydrophilic loop (ECL) 2 region. Phylogenetic analysis demonstrated that the MaCXCRs were clustered together with homologous proteins from other fish. Taken together with the amino acid identity and similarity analysis, these results suggested that the MaCXCRs are conserved with other homologous genes, in which CXCR4 is more conserved than CXCR1-3. The MaCXCRs loci showed conserved synteny among teleost fish, and we found that human CXCR1 shares a common ancestor with fish CXCR1a. MaCXCRs were constitutively expressed in a wide range of tissues (especially in immune-related tissues) with different expression levels, suggesting that the MaCXCRs have different roles in un-stimulated tissues, and may play vital roles under normal conditions. MaCXCRs showed different fold changes in the spleen after Aeromonas veronii and polyinosinic-polycytidylic acid (poly I:C) challenge, which suggested that MaCXCR1a and MaCXCR3a have longer antiviral activities compared with their antibacterial functions, and that MaCXCR1b possesses stronger antiviral than antibacterial activity. MaCXCR4 may play vital roles during bacterial and viral infection; however, MaCXCR2 has relatively small effect in antibacterial and antiviral responses. The differential responses of these genes to bacteria and poly I:C implied the differences in the mechanisms of defense against viruses and bacteria.
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Affiliation(s)
- Weihua Gao
- Engineering Research Center of Ecology and Agricultural Use of Wetland (Ministry of Education), Yangtze University, Jingzhou, 434024, PR China; Guangxi Key Laboratory of Marine Biotechnology, Guangxi Institute of Oceanology, Beihai, 536006, PR China
| | - Shuai Li
- Engineering Research Center of Ecology and Agricultural Use of Wetland (Ministry of Education), Yangtze University, Jingzhou, 434024, PR China; Guangxi Key Laboratory of Marine Biotechnology, Guangxi Institute of Oceanology, Beihai, 536006, PR China
| | - Qiaoqing Xu
- Engineering Research Center of Ecology and Agricultural Use of Wetland (Ministry of Education), Yangtze University, Jingzhou, 434024, PR China
| | - Dashi Zhu
- Engineering Research Center of Ecology and Agricultural Use of Wetland (Ministry of Education), Yangtze University, Jingzhou, 434024, PR China
| | - Qin Zhang
- Guangxi Key Laboratory of Marine Biotechnology, Guangxi Institute of Oceanology, Beihai, 536006, PR China
| | - Kai Luo
- Engineering Research Center of Ecology and Agricultural Use of Wetland (Ministry of Education), Yangtze University, Jingzhou, 434024, PR China; The Key Laboratory of Mariculture (Education Ministry of China), Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China.
| | - Wenbing Zhang
- Engineering Research Center of Ecology and Agricultural Use of Wetland (Ministry of Education), Yangtze University, Jingzhou, 434024, PR China; The Key Laboratory of Mariculture (Education Ministry of China), Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China.
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10
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Xu Q, Luo K, Zhang S, Gao W, Zhang W, Wei Q. Sequence analysis and characterization of type I interferon and type II interferon from the critically endangered sturgeon species, A. dabryanus and A. sinensis. FISH & SHELLFISH IMMUNOLOGY 2019; 84:390-403. [PMID: 30336282 DOI: 10.1016/j.fsi.2018.10.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Revised: 10/07/2018] [Accepted: 10/14/2018] [Indexed: 06/08/2023]
Abstract
In the present study, we identify three type I interferon (IFN) genes (Ad/AsIFNe1-3) and a type II IFN gene (Ad/AsIFNγ) from the Dabry's sturgeon (Acipenser dabryanus) and the Chinese sturgeon (Acipenser sinensis). Sequence analysis revealed that Ad/AsIFNe1-3 and Ad/AsIFNγ contain several conserved characteristics, including signal peptides, interferon alpha, beta, and delta (IFabd) domains, and N-glycosylation sites. Ad/AsIFNe1-3 belongs to the type I IFN group I subgroup, possessing two conserved cysteines residues (C1 and C3), and Ad/AsIFNγ contained a conserved nuclear localization sequence (NLS) motif. Ad/AsIFNe1-3 and Ad/AsIFNγ contain signature motifs indicative of their corresponding IFN group. The Ad/AsIFNe1-3 and Ad/AsIFNγ genes were found to consist of 5 exons/4 introns and 4 exons/3 introns, respectively. These IFNs were separated by four phase 0 introns (type I IFN) and three phase 0 introns (type II IFN). The sequences of IFNe1-3 and IFNγ from the Dabry's sturgeon and the Chinese sturgeon were closely aligned, suggested that these two species are closely related. Phylogenetic analysis revealed that Ad/AsIFNe1-3 and Ad/AsIFNγ clustered together with the corresponding homologous proteins from other fish species. AdIFNe1-3 were found to be high expressed in early embryonic development, suggesting that AdIFNe1-3 might indicate maternal transmission, while AdIFNγ may not mediate embryonic development. Tissue distribution analysis revealed that AdIFNe1-3 and AdIFNγ carry out biological functions in immune and non-immune tissues compartments. AdIFNe1-3 and AdIFNγ can be stimulated by polyinosinic-polycytidylic acid (poly I:C) and lipopolysaccharides (LPS). AdIFNe1-3 have stronger antiviral activity than AdIFNγ, and AdIFNγ has a stronger antibacterial activity than AdIFNe1-3. The differential responses of these genes to poly I:C and LPS suggest differences in the mechanisms of defense against viruses and bacteria.
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Affiliation(s)
- Qiaoqing Xu
- School of Animal Science, Yangtze University, Jingzhou, 434020, China; Guangxi Key Laboratory of Marine Biotechnology, Guangxi Institute of Oceanology, Beihai, 536006, China; State Key Laboratory of Developmental Biology of Freshwater Fish, Changsha, 410081, China
| | - Kai Luo
- School of Animal Science, Yangtze University, Jingzhou, 434020, China; The Key Laboratory of Mariculture (Education Ministry of China), Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China.
| | - Shuhuan Zhang
- Key Lab of Freshwater Biodiversity Conservation Ministry of Agriculture, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China
| | - Weihua Gao
- School of Animal Science, Yangtze University, Jingzhou, 434020, China; Guangxi Key Laboratory of Marine Biotechnology, Guangxi Institute of Oceanology, Beihai, 536006, China; State Key Laboratory of Developmental Biology of Freshwater Fish, Changsha, 410081, China
| | - Wenbing Zhang
- School of Animal Science, Yangtze University, Jingzhou, 434020, China; The Key Laboratory of Mariculture (Education Ministry of China), Ocean University of China, 5 Yushan Road, Qingdao, Shandong, 266003, PR China
| | - Qiwei Wei
- Key Lab of Freshwater Biodiversity Conservation Ministry of Agriculture, Yangtze River Fisheries Research Institute, Chinese Academy of Fishery Sciences, Wuhan, 430223, China.
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11
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Mass Spectrometry-based Structural Analysis and Systems Immunoproteomics Strategies for Deciphering the Host Response to Endotoxin. J Mol Biol 2018; 430:2641-2660. [PMID: 29949751 DOI: 10.1016/j.jmb.2018.06.032] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Revised: 05/23/2018] [Accepted: 06/15/2018] [Indexed: 02/06/2023]
Abstract
One cause of sepsis is systemic maladaptive immune response of the host to bacteria and specifically, to Gram-negative bacterial outer-membrane glycolipid lipopolysaccharide (LPS). On the host myeloid cell surface, proinflammatory LPS activates the innate immune system via Toll-like receptor-4/myeloid differentiation factor-2 complex. Intracellularly, LPS is also sensed by the noncanonical inflammasome through caspase-11 in mice and 4/5 in humans. The minimal functional determinant for innate immune activation is the membrane anchor of LPS called lipid A. Even subtle modifications to the lipid A scaffold can enable, diminish, or abolish immune activation. Bacteria are known to modify their LPS structure during environmental stress and infection of hosts to alter cellular immune phenotypes. In this review, we describe how mass spectrometry-based structural analysis of endotoxin helped uncover major determinations of molecular pathogenesis. Through characterization of LPS modifications, we now better understand resistance to antibiotics and cationic antimicrobial peptides, as well as how the environment impacts overall endotoxin structure. In addition, mass spectrometry-based systems immunoproteomics approaches can assist in elucidating the immune response against LPS. Many regulatory proteins have been characterized through proteomics and global/targeted analysis of protein modifications, enabling the discovery and characterization of novel endotoxin-mediated protein translational modifications.
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12
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Zhang S, Cao X, Gao Q, Liu Y. Protein glycosylation in viral hepatitis-related HCC: Characterization of heterogeneity, biological roles, and clinical implications. Cancer Lett 2017; 406:64-70. [DOI: 10.1016/j.canlet.2017.07.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 07/26/2017] [Accepted: 07/30/2017] [Indexed: 12/12/2022]
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13
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Iijima J, Kobayashi S, Kitazume S, Kizuka Y, Fujinawa R, Korekane H, Shibata T, Saitoh SI, Akashi-Takamura S, Miyake K, Miyoshi E, Taniguchi N. Core fucose is critical for CD14-dependent Toll-like receptor 4 signaling. Glycobiology 2017; 27:1006-1015. [DOI: 10.1093/glycob/cwx075] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 08/21/2017] [Indexed: 01/28/2023] Open
Affiliation(s)
- Junko Iijima
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Satoshi Kobayashi
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Shinobu Kitazume
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yasuhiko Kizuka
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Reiko Fujinawa
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroaki Korekane
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Takuma Shibata
- Division of Innate Immunity, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Shin-Ichiroh Saitoh
- Division of Innate Immunity, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Sachiko Akashi-Takamura
- Department of Microbiology and Immunology, Aichi Medical University School of Medicine, Aichi 480-1195, Japan
| | - Kensuke Miyake
- Division of Innate Immunity, Institute of Medical Science, The University of Tokyo, Tokyo 108-8639, Japan
| | - Eiji Miyoshi
- Department of Molecular Biochemistry and Clinical Investigation, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan
| | - Naoyuki Taniguchi
- Disease Glycomics Team, RIKEN-Max Planck Joint Research Center, Global Research Cluster, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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da Silva TA, Zorzetto-Fernandes ALV, Cecílio NT, Sardinha-Silva A, Fernandes FF, Roque-Barreira MC. CD14 is critical for TLR2-mediated M1 macrophage activation triggered by N-glycan recognition. Sci Rep 2017; 7:7083. [PMID: 28765651 PMCID: PMC5539197 DOI: 10.1038/s41598-017-07397-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 06/28/2017] [Indexed: 12/22/2022] Open
Abstract
Agonist interaction with Toll-like receptors (TLRs) induces T cell-mediated immunity, which is effective against intracellular pathogens. Consequently, TLR agonists are being tried as immunomodulatory agents. The lectin ArtinM targets TLR2 N-glycans on macrophages, induces cytokines production, and promotes T helper-1 immunity, a process that culminates in resistance to several parasitic and fungal infections in vivo. Because co-receptors influence agonist binding to TLRs, we investigated whether CD14 is required for macrophage activation induced by ArtinM. Macrophages from wild-type mice stimulated by ArtinM not only produced cytokines but also had the following activation profile: (i) expression of M1 polarization markers; (ii) nitrite oxide production; (iii) cellular migration; (iv) enhanced phagocytic and fungicide activity; (v) modulation of TLR2 expression; and (vi) activation of NF-κB pathway. This activation profile induced by ArtinM was evaluated in macrophages lacking CD14 that showed none of the ArtinM effects. We demonstrated by immunoprecipitation and sugar inhibition assays the physical interaction of ArtinM, TLR2, and CD14, which depends on recognition of the trimannoside that constitutes the core of N-glycans. Thus, our study showed that CD14 is critical for ArtinM-induced macrophage activation, providing fundamental insight into the design of anti-infective therapies based on carbohydrate recognition.
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Affiliation(s)
- Thiago Aparecido da Silva
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto, 14049-900, São Paulo, Brazil
| | - André L V Zorzetto-Fernandes
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto, 14049-900, São Paulo, Brazil
| | - Nerry T Cecílio
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto, 14049-900, São Paulo, Brazil
| | - Aline Sardinha-Silva
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto, 14049-900, São Paulo, Brazil
| | - Fabrício Freitas Fernandes
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto, 14049-900, São Paulo, Brazil
| | - Maria Cristina Roque-Barreira
- Departamento de Biologia Celular e Molecular e Bioagentes Patogênicos, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto, 14049-900, São Paulo, Brazil.
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15
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Marinkovic E, Djokic R, Lukic I, Filipovic A, Inic-Kanada A, Kosanovic D, Gavrovic-Jankulovic M, Stojanovic M. Modulation of functional characteristics of resident and thioglycollate-elicited peritoneal murine macrophages by a recombinant banana lectin. PLoS One 2017; 12:e0172469. [PMID: 28235050 PMCID: PMC5325268 DOI: 10.1371/journal.pone.0172469] [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: 10/13/2016] [Accepted: 02/06/2017] [Indexed: 01/25/2023] Open
Abstract
We demonstrated that a recombinant banana lectin (rBanLec), which structural characteristics and physiological impacts highly resemble those reported for its natural counterparts, binds murine peritoneal macrophages and specifically modulates their functional characteristics. By using rBanLec in concentrations ranging from 1 μg to 10 μg to stimulate resident (RMs) and thioglycollate-elicited (TGMs) peritoneal macrophages from BALB/c and C57BL/6 mice, we have shown that effects of rBanLec stimulation depend on its concentration but also on the functional status of macrophages and their genetic background. rBanLec, in a positive dose-dependent manner, promotes the proliferation of TGMs from both BALB/c and C57BL/6 mice, while its mitogenic influence on RMs is significantly lower (BALB/c mice) or not detectable (C57BL/6 mice). In all peritoneal macrophages, irrespective of their type and genetic background, rBanLec, in a positive dose dependent manner, enhances the secretion of IL-10. rBanLec stimulation of RMs from both BALB/c and C57BL/6 resulted in a positive dose-dependent promotion of proinflammatory phenotype (enhancement of NO production and IL-12 and TNFα secretion, reduction of arginase activity). Positive dose-dependent skewing toward proinflammatory phenotype was also observed in TGMs from C57BL/6 mice. However, the enhancement of rBanLec stimulation promotes skewing of TGMs from BALB/c mice towards anti-inflammatory profile (reduction of NO production and IL-12 secretion, enhancement of arginase activity and TGFβ and IL-4 secretion). Moreover, we established that rBanLec binds oligosaccharide structures of TLR2 and CD14 and that blocking of signaling via these receptors significantly impairs the production of TNFα and NO in BALB/c macrophages. Since the outcome of rBanLec stimulation depends on rBanLec concentration as well as on the functional characteristics of its target cells and their genetic background, further studies are needed to investigate its effects under physiological and specific pathological conditions.
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Affiliation(s)
- Emilija Marinkovic
- Department of Research and Development; Institute of Virology, Vaccines and Sera–TORLAK; Belgrade, Serbia
| | - Radmila Djokic
- Department of Research and Development; Institute of Virology, Vaccines and Sera–TORLAK; Belgrade, Serbia
| | - Ivana Lukic
- Department of Research and Development; Institute of Virology, Vaccines and Sera–TORLAK; Belgrade, Serbia
| | - Ana Filipovic
- Department of Research and Development; Institute of Virology, Vaccines and Sera–TORLAK; Belgrade, Serbia
| | - Aleksandra Inic-Kanada
- OCUVAC–Center of Ocular Inflammation and Infection, Laura Bassi Centres of Expertise; Center for Pathophysiology, Infectiology and Immunology; Medical University of Vienna; Vienna, Austria
| | - Dejana Kosanovic
- Department of Research and Development; Institute of Virology, Vaccines and Sera–TORLAK; Belgrade, Serbia
| | | | - Marijana Stojanovic
- Department of Research and Development; Institute of Virology, Vaccines and Sera–TORLAK; Belgrade, Serbia
- * E-mail:
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16
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Kanabar V, Tedaldi L, Jiang J, Nie X, Panina I, Descroix K, Man F, Pitchford SC, Page CP, Wagner GK. Base-modified UDP-sugars reduce cell surface levels of P-selectin glycoprotein 1 (PSGL-1) on IL-1β-stimulated human monocytes. Glycobiology 2016; 26:1059-1071. [PMID: 27233805 PMCID: PMC5072147 DOI: 10.1093/glycob/cww053] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 04/07/2016] [Accepted: 04/22/2016] [Indexed: 12/26/2022] Open
Abstract
P-selectin glycoprotein ligand-1 (PSGL-1, CD162) is a cell-surface glycoprotein that is expressed, either constitutively or inducibly, on all myeloid and lymphoid cell lineages. PSGL-1 is implicated in cell-cell interactions between platelets, leukocytes and endothelial cells, and a key mediator of inflammatory cell recruitment and transmigration into tissues. Here, we have investigated the effects of the β-1,4-galactosyltransferase inhibitor 5-(5-formylthien-2-yl) UDP-Gal (5-FT UDP-Gal, compound 1: ) and two close derivatives on the cell surface levels of PSGL-1 on human peripheral blood mononuclear cells (hPBMCs). PSGL-1 levels were studied both under basal conditions, and upon stimulation of hPBMCs with interleukin-1β (IL-1β). Between 1 and 24 hours after IL-1β stimulation, we observed initial PSGL-1 shedding, followed by an increase in PSGL-1 levels on the cell surface, with a maximal window between IL-1β-induced and basal levels after 72 h. All three inhibitors reduce PSGL-1 levels on IL-1β-stimulated cells in a concentration-dependent manner, but show no such effect in resting cells. Compound 1: also affects the cell surface levels of adhesion molecule CD11b in IL-1β-stimulated hPBMCs, but not of glycoproteins CD14 and CCR2. This activity profile may be linked to the inhibition of global Sialyl Lewis presentation on hPBMCs by compound 1: , which we have also observed. Although this mechanistic explanation remains hypothetical at present, our results show, for the first time, that small molecules can discriminate between IL-1β-induced and basal levels of cell surface PSGL-1. These findings open new avenues for intervention with PSGL-1 presentation on the cell surface of primed hPBMCs and may have implications for anti-inflammatory drug development.
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Affiliation(s)
- Varsha Kanabar
- Sackler Institute of Pulmonary Pharmacology
- Institute of Pharmaceutical Science, King's College London, Franklin Wilkins Building, London SE1 9NH, UK
| | - Lauren Tedaldi
- Institute of Pharmaceutical Science, King's College London, Franklin Wilkins Building, London SE1 9NH, UK
- Department of Chemistry, Faculty of Natural & Mathematical Sciences, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Jingqian Jiang
- Department of Chemistry, Faculty of Natural & Mathematical Sciences, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
| | - Xiaodan Nie
- Sackler Institute of Pulmonary Pharmacology
- Institute of Pharmaceutical Science, King's College London, Franklin Wilkins Building, London SE1 9NH, UK
| | - Irina Panina
- Institute of Pharmaceutical Science, King's College London, Franklin Wilkins Building, London SE1 9NH, UK
| | - Karine Descroix
- School of Pharmacy, University of East Anglia, Norwich, NR4 7TJ, UK
| | - Francis Man
- Sackler Institute of Pulmonary Pharmacology
- Institute of Pharmaceutical Science, King's College London, Franklin Wilkins Building, London SE1 9NH, UK
| | - Simon C Pitchford
- Sackler Institute of Pulmonary Pharmacology
- Institute of Pharmaceutical Science, King's College London, Franklin Wilkins Building, London SE1 9NH, UK
| | - Clive P Page
- Sackler Institute of Pulmonary Pharmacology
- Institute of Pharmaceutical Science, King's College London, Franklin Wilkins Building, London SE1 9NH, UK
| | - Gerd K Wagner
- Department of Chemistry, Faculty of Natural & Mathematical Sciences, King's College London, Britannia House, 7 Trinity Street, London, SE1 1DB, UK
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17
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CD14 mediates binding of high doses of LPS but is dispensable for TNF-α production. Mediators Inflamm 2013; 2013:824919. [PMID: 24489448 PMCID: PMC3892557 DOI: 10.1155/2013/824919] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2013] [Revised: 08/29/2013] [Accepted: 10/11/2013] [Indexed: 01/08/2023] Open
Abstract
Activation of macrophages with lipopolysaccharide (LPS) involves a sequential engagement of serum LPS-binding protein (LBP), plasma membrane CD14, and TLR4/MD-2 signaling complex. We analyzed participation of CD14 in TNF-α production stimulated with 1-1000 ng/mL of smooth or rough LPS (sLPS or rLPS) and in sLPS binding to RAW264 and J744 cells. CD14 was indispensable for TNF-α generation induced by a low concentration, 1 ng/mL, of sLPS and rLPS. At higher doses of both LPS forms (100-1000 ng/mL), TNF-α release required CD14 to much lower extent. Among the two forms of LPS, rLPS-induced TNF-α production was less CD14-dependent and could proceed in the absence of serum as an LBP source. On the other hand, the involvement of CD14 was crucial for the binding of 1000 ng/mL of sLPS judging from an inhibitory effect of the anti-CD14 antibody. The binding of sLPS was also strongly inhibited by dextran sulfate, a competitive ligand of scavenger receptors (SR). In the presence of dextran sulfate, sLPS-induced production of TNF-α was upregulated about 1.6-fold. The data indicate that CD14 together with SR participates in the binding of high doses of sLPS. However, CD14 contribution to TNF α production induced by high concentrations of sLPS and rLPS can be limited.
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18
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Kelley SL, Lukk T, Nair SK, Tapping RI. The crystal structure of human soluble CD14 reveals a bent solenoid with a hydrophobic amino-terminal pocket. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2013; 190:1304-11. [PMID: 23264655 PMCID: PMC3552104 DOI: 10.4049/jimmunol.1202446] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Human monocyte differentiation Ag CD14 is a pattern recognition receptor that enhances innate immune responses to infection by sensitizing host cells to bacterial LPS (endotoxin), lipoproteins, lipoteichoic acid, and other acylated microbial products. CD14 physically delivers these lipidated microbial products to various TLR signaling complexes that subsequently induce intracellular proinflammatory signaling cascades upon ligand binding. The ensuing cellular responses are usually protective to the host but can also result in host fatality through sepsis. In this work, we have determined the x-ray crystal structure of human CD14. The structure reveals a bent solenoid typical of leucine-rich repeat proteins with an amino-terminal pocket that presumably binds acylated ligands including LPS. Comparison of human and mouse CD14 structures shows great similarity in overall protein fold. However, compared with mouse CD14, human CD14 contains an expanded pocket and alternative rim residues that are likely to be important for LPS binding and cell activation. The x-ray crystal structure of human CD14 presented in this article may foster additional ligand-bound structural studies, virtual docking studies, and drug design efforts to mitigate LPS-induced sepsis and other inflammatory diseases.
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Affiliation(s)
- Stacy L. Kelley
- Department of Biochemistry, University of Illinois at Urbana-Champaign
| | - Tiit Lukk
- Department of Biochemistry, University of Illinois at Urbana-Champaign
| | - Satish K. Nair
- Department of Biochemistry, University of Illinois at Urbana-Champaign
| | - Richard I. Tapping
- Department of Microbiology, University of Illinois at Urbana-Champaign
- College of Medicine, University of Illinois at Urbana-Champaign
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19
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Schneider OD, Millen SH, Weiss AA, Miller WE. Mechanistic insight into pertussis toxin and lectin signaling using T cells engineered to express a CD8α/CD3ζ chimeric receptor. Biochemistry 2012; 51:4126-37. [PMID: 22551306 DOI: 10.1021/bi3002693] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mammalian cell-surface receptors typically display N- or O-linked glycans added post-translationally. Plant lectins such as phytohemagluttinin (PHA) can activate the T cell receptor (TCR) and other cell-surface receptors by binding to glycans and initiating receptor cross-linking. Pathogenic microorganisms such as Bordetella pertussis also express proteins with lectin-like activities. Similar to plant lectins, pertussis toxin (PTx) can activate the TCR and bind to a variety of glycans. However, whether the lectin-like activity of PTx is responsible for its ability to activate TCR signaling has not been formally proven. Here we examined the ability of PTx and a panel of lectins to activate the TCR or a CD8α/CD3ζ chimeric receptor (termed CD8ζ). We demonstrate that CD8ζ rescues PTx-induced signaling events lacking in TCR null cells. This result indicates that CD8ζ can substitute for TCR and supports the hypothesis that PTxB (functioning as a lectin) stimulates signaling via receptor cross-linking rather than by binding to a specific epitope on the TCR. Moreover, PTx is able to activate signaling by binding either N-linked or O-linked glycan-modified receptors as the TCR displays N-linked glycans while CD8ζ displays O-linked glycans. Finally, studies with a diverse panel of lectins indicate that the signaling activity of the lectins does not always correlate with the biochemical reports of ligand preferences. Comparison of lectin signaling through TCR or CD8ζ allows us to better define the structural and functional properties of lectin-glycan interactions using a biologically based signaling readout.
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Affiliation(s)
- Olivia D Schneider
- Department of Molecular Genetics, Biochemistry, and Microbiology, University of Cincinnati College of Medicine, Cincinnati, OH 45267, USA
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20
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Feng C, Stamatos NM, Dragan AI, Medvedev A, Whitford M, Zhang L, Song C, Rallabhandi P, Cole L, Nhu QM, Vogel SN, Geddes CD, Cross AS. Sialyl residues modulate LPS-mediated signaling through the Toll-like receptor 4 complex. PLoS One 2012; 7:e32359. [PMID: 22496731 PMCID: PMC3322133 DOI: 10.1371/journal.pone.0032359] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2011] [Accepted: 01/26/2012] [Indexed: 11/19/2022] Open
Abstract
We previously reported that neuraminidase (NA) pretreatment of human PBMCs markedly increased their cytokine response to lipopolysaccharide (LPS). To study the mechanisms by which this occurs, we transfected HEK293T cells with plasmids encoding TLR4, CD14, and MD2 (three components of the LPS receptor complex), as well as a NFκB luciferase reporting system. Both TLR4 and MD2 encoded by the plasmids are α-2,6 sialylated. HEK293T cells transfected with TLR4/MD2/CD14 responded robustly to the addition of LPS; however, omission of the MD2 plasmid abrogated this response. Addition of culture supernatants from MD2 (sMD2)-transfected HEK293T cells, but not recombinant, non-glycosylated MD2 reconstituted this response. NA treatment of sMD2 enhanced the LPS response as did NA treatment of the TLR4/CD14-transfected cell supplemented with untreated sMD2, but optimal LPS-initiated responses were observed with NA-treated TLR4/CD14-transfected cells supplemented with NA-treated sMD2. We hypothesized that removal of negatively charged sialyl residues from glycans on the TLR4 complex would hasten the dimerization of TLR4 monomers required for signaling. Co-transfection of HEK293T cells with separate plasmids encoding either YFP- or FLAG-tagged TLR4, followed by treatment with NA and stimulation with LPS, led to an earlier and more robust time-dependent dimerization of TLR4 monomers on co-immunoprecipitation, compared to untreated cells. These findings were confirmed by fluorescence resonance energy transfer (FRET) analysis. Overexpression of human Neu1 increased LPS-initiated TLR4-mediated NFκB activation and a NA inhibitor suppressed its activation. We conclude that (1) sialyl residues on TLR4 modulate LPS responsiveness, perhaps by facilitating clustering of the homodimers, and that (2) sialic acid, and perhaps other glycosyl species, regulate MD2 activity required for LPS-mediated signaling. We speculate that endogenous sialidase activity mobilized during cell activation may play a role in this regulation.
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Affiliation(s)
- Chiguang Feng
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Nicholas M. Stamatos
- Institute of Human Virology and Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Anatoliy I. Dragan
- Institute of Fluorescence, University of Maryland, Baltimore County, Baltimore, Maryland, United States of America
| | - Andrei Medvedev
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Melissa Whitford
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Lei Zhang
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Chang Song
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Prasad Rallabhandi
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Leah Cole
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Quan M. Nhu
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Stefanie N. Vogel
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
| | - Chris D. Geddes
- Institute of Fluorescence, University of Maryland, Baltimore County, Baltimore, Maryland, United States of America
| | - Alan S. Cross
- Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, Maryland, United States of America
- * E-mail:
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21
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Lu D, Yang C, Liu Z. How hydrophobicity and the glycosylation site of glycans affect protein folding and stability: a molecular dynamics simulation. J Phys Chem B 2011; 116:390-400. [PMID: 22118044 DOI: 10.1021/jp203926r] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Glycosylation is one of the most common post-translational modifications in the biosynthesis of protein, but its effect on the protein conformational transitions underpinning folding and stabilization is poorly understood. In this study, we present a coarse-grained off-lattice 46-β barrel model protein glycosylated by glycans with different hydrophobicity and glycosylation sites to examine the effect of glycans on protein folding and stabilization using a Langevin dynamics simulation, in which an H term was proposed as the index of the hydrophobicity of glycan. Compared with its native counterpart, introducing glycans of suitable hydrophobicity (0.1 < H < 0.4) at flexible peptide residues of this model protein not only facilitated folding of the protein but also increased its conformation stability significantly. On the contrary, when glycans were introduced at the restricted peptide residues of the protein, only those hydrophilic (H = 0) or very weak hydrophobic (H < 0.2) ones contributed slightly to protein stability but hindered protein folding due to increased free energy barriers. The glycosylated protein retained the two-step folding mechanism in terms of hydrophobic collapse and structural rearrangement. Glycan chains located in a suitable site with an appropriate hydrophobicity facilitated both collapse and rearrangement, whereas others, though accelerating collapse, hindered rearrangement. In addition to entropy effects, that is, narrowing the space of the conformations of the unfolded state, the presence of glycans with suitable hydrophobicity at suitable glycosylation site strengthened the folded state via hydrophobic interaction, that is, the enthalpy effect. The simulations have shown both the stabilization and the destabilization effects of glycosylation, as experimentally reported in the literature, and provided molecular insight into glycosylated proteins. The understanding of the effects of glycans with different hydrophobicities on the folding and stability of protein, as attempted by the present work, is helpful not only to explain the stabilization and destabilization effect of real glycoproteins but also to design protein-polymer conjugates for biotechnological purposes.
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Affiliation(s)
- Diannan Lu
- Department of Chemical Engineering, Tsinghua University, Beijing, China
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22
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Pal A, Sharma A, Bhattacharya TK, Chatterjee PN, Chakravarty AK. Molecular Characterization and SNP Detection of CD14 Gene of Crossbred Cattle. Mol Biol Int 2011; 2011:507346. [PMID: 22132326 PMCID: PMC3205722 DOI: 10.4061/2011/507346] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2011] [Revised: 07/19/2011] [Accepted: 07/19/2011] [Indexed: 12/02/2022] Open
Abstract
CD14 is an important molecule for innate immunity that can act against a wide range of pathogens. The present paper has characterized CD14 gene of crossbred (CB) cattle (Bos indicus×Bos taurus). Cloning and sequence analysis of CD14 cDNA revealed 1119 nucleotide long open reading frame encoding 373 amino acids protein and 20 amino acids signal peptide. CB cattle CD14 gene exhibited a high percentage of nucleotide identity (59.3–98.1%) with the corresponding mammalian homologs. Cattle and buffalo appear to have diverged from a common ancestor in phylogenetic analysis. 25 SNPs with 17 amino acid changes were newly reported and the site for mutational hot-spot was detected in CB cattle CD14 gene. Non-synonymous substitutions exceeding synonymous substitutions indicate the evolution of this protein through positive selection among domestic animals. Predicted protein structures obtained from deduced amino acid sequence indicated CB cattle CD14 molecule to be a receptor with horse shoe-shaped structure. The sites for LPS binding, LPS signalling, leucine-rich repeats, putative N-linked glycosylation, O-linked glycosylation, glycosyl phosphatidyl inositol anchor, disulphide bridges, alpha helix, beta strand, leucine rich nuclear export signal, leucine zipper and domain linker were predicted. Most of leucine and cysteine residues remain conserved across the species.
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Affiliation(s)
- Aruna Pal
- Animal Genetics Division, Indian Veterinary Research Institute, Izatnagar, Pin-243122, India
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23
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Meng J, Lien E, Golenbock DT. MD-2-mediated ionic interactions between lipid A and TLR4 are essential for receptor activation. J Biol Chem 2009; 285:8695-702. [PMID: 20018893 DOI: 10.1074/jbc.m109.075127] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Lipopolysaccharide (LPS) activates innate immune responses through TLR4.MD-2. LPS binds to the MD-2 hydrophobic pocket and bridges the dimerization of two TLR4.MD-2 complexes to activate intracellular signaling. However, exactly how lipid A, the endotoxic moiety of LPS, activates myeloid lineage cells remains unknown. Lipid IV(A), a tetra-acylated lipid A precursor, has been used widely as a model for lipid A activation. For unknown reasons, lipid IV(A) activates proinflammatory responses in rodent cells but inhibits the activity of LPS in human cells. Using stable TLR4-expressing cell lines and purified monomeric MD-2, as well as MD-2-deficient bone marrow-derived macrophages, we found that both mouse TLR4 and mouse MD-2 are required for lipid IV(A) activation. Computational studies suggested that unique ionic interactions exist between lipid IV(A) and TLR4 at the dimerization interface in the mouse complex only. The negatively charged 4'-phosphate on lipid IV(A) interacts with two positively charged residues on the opposing mouse, but not human, TLR4 (Lys(367) and Arg(434)) at the dimerization interface. When replaced with their negatively charged human counterparts Glu(369) and Gln(436), mouse TLR4 was no longer responsive to lipid IV(A). In contrast, human TLR4 gained lipid IV(A) responsiveness when ionic interactions were enabled by charge reversal at the dimerization interface, defining the basis of lipid IV(A) species specificity. Thus, using lipid IV(A) as a selective lipid A agonist, we successfully decoupled and coupled two sequential events required for intracellular signaling: receptor engagement and dimerization, underscoring the functional role of ionic interactions in receptor activation.
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Affiliation(s)
- Jianmin Meng
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA
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24
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Waetzig GH, Chalaris A, Rosenstiel P, Suthaus J, Holland C, Karl N, Vallés Uriarte L, Till A, Scheller J, Grötzinger J, Schreiber S, Rose-John S, Seegert D. N-linked glycosylation is essential for the stability but not the signaling function of the interleukin-6 signal transducer glycoprotein 130. J Biol Chem 2009; 285:1781-9. [PMID: 19915009 DOI: 10.1074/jbc.m109.075952] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
N-Linked glycosylation is an important determinant of protein structure and function. The interleukin-6 signal transducer glycoprotein 130 (gp130) is a common co-receptor for cytokines of the interleukin (IL)-6 family and is N-glycosylated at 9 of 11 potential sites. Whereas N-glycosylation of the extracellular domains D1-D3 of gp130 has been shown to be dispensable for binding of the gp130 ligand IL-6 and its cognate receptor in vitro, the role of the N-linked glycans on domains D4 and D6 is still unclear. We have mutated the asparagines of all nine functional N-glycosylation sites of gp130 to glutamine and systematically analyzed the consequences of deleted N-glycosylation (dNG) in both cellular gp130 and in a soluble gp130-IgG1-Fc fusion protein (sgp130Fc). Our results show that sgp130Fc-dNG is inherently unstable and degrades rapidly under conditions that do not harm wild-type sgp130Fc. Consistently, the bulk of cellular gp130-dNG is not transported to the plasma membrane but is degraded in the proteasome. However, the small quantities of gp130-dNG, which do reach the cell surface, are still able to activate the key gp130 signaling target signal transducer and activator of transcription-3 (STAT3) upon binding of the agonistic complex of IL-6 and soluble IL-6 receptor. In conclusion, N-linked glycosylation is required for the stability but not the signal-transducing function of gp130.
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Frey T, De Maio A. The antifungal agent itraconazole induces the accumulation of high mannose glycoproteins in macrophages. J Biol Chem 2009; 284:16882-16890. [PMID: 19414590 DOI: 10.1074/jbc.m109.007609] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Bacterial lipopolysaccharide (LPS) is a key mediator in the development of Gram-negative septic shock, which is a major health problem. The effect of LPS on myeloid cells is mediated by a multicomplex receptor system in which CD14, a glycosylphosphatidylinositol-anchored glycoprotein, and Toll-like receptor 4 are the major players. We have found that incubation of macrophages with itraconazole (ICZ), an azole antifungal commonly used in humans, altered both the expression and glycosylation of CD14. This glycoprotein, which is endo H-resistant in untreated cells, becomes endo H-sensitive following ICZ treatment. The effect of ICZ on glycan processing was observed in all newly synthesized glycoproteins as indicated by incorporation of [2-(3)H]mannose. In addition, cells treated with ICZ increased surface concanavalin A (ConA) binding, corroborating an increase in high mannose surface glycoproteins. Although the glycosylation pattern of CD14 was altered, this glycoprotein was delivered to the cell surface or was secreted. Moreover, it appeared functional as demonstrated by the release of LPS-induced tumor necrosis factor-alpha under conditions specific for a CD14-mediated activation process. The effect of ICZ on glycosylation was not dependent on inhibition of the cholesterol biosynthetic pathway and was specific for this drug because other azole antifungals, such as ketoconazole and econazole, did not alter glycan processing. These results suggest a possible secondary effect of ICZ that impacts the processing of glyconjugates and may alter cellular function and homeostasis.
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Affiliation(s)
- Tiffany Frey
- Graduate Program in Cellular and Molecular Medicine and Department of Physiology, The Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205
| | - Antonio De Maio
- Graduate Program in Cellular and Molecular Medicine and Department of Physiology, The Johns Hopkins University, School of Medicine, Baltimore, Maryland 21205; From the Department of Surgery, University of California, San Diego, School of Medicine, La Jolla, California 92093.
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