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Bai Y, Min R, Chen P, Mei S, Deng F, Zheng Z, Jiang C, Miao R, Wu Z, Zhang P, Pan Y, Lieberman J, Liu X. Disulfiram blocks inflammatory TLR4 signaling by targeting MD-2. Proc Natl Acad Sci U S A 2023; 120:e2306399120. [PMID: 37487070 PMCID: PMC10401014 DOI: 10.1073/pnas.2306399120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Accepted: 06/23/2023] [Indexed: 07/26/2023] Open
Abstract
Toll-like receptor 4 (TLR4) sensing of lipopolysaccharide (LPS), the most potent pathogen-associated molecular pattern of gram-negative bacteria, activates NF-κB and Irf3, which induces inflammatory cytokines and interferons that trigger an intense inflammatory response, which is critical for host defense but can also cause serious inflammatory pathology, including sepsis. Although TLR4 inhibition is an attractive therapeutic approach for suppressing overexuberant inflammatory signaling, previously identified TLR4 antagonists have not shown any clinical benefit. Here, we identify disulfiram (DSF), an FDA-approved drug for alcoholism, as a specific inhibitor of TLR4-mediated inflammatory signaling. TLR4 cell surface expression, LPS sensing, dimerization and signaling depend on TLR4 binding to MD-2. DSF and other cysteine-reactive drugs, previously shown to block LPS-triggered inflammatory cell death (pyroptosis), inhibit TLR4 signaling by covalently modifying Cys133 of MD-2, a key conserved residue that mediates TLR4 sensing and signaling. DSF blocks LPS-triggered inflammatory cytokine, chemokine, and interferon production by macrophages in vitro. In the aggressive N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine mouse model of Parkinson's disease (PD) in which TLR4 plays an important role, DSF markedly suppresses neuroinflammation and dopaminergic neuron loss, and restores motor function. Our findings identify a role for DSF in curbing TLR4-mediated inflammation and suggest that DSF and other drugs that target MD-2 might be useful for treating PD and other diseases in which inflammation contributes importantly to pathogenesis.
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Affiliation(s)
- Yang Bai
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai200031, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Rui Min
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai200031, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Pengcheng Chen
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai200031, China
| | - Shenglin Mei
- Department of Biomedical Informatics, Harvard Medical School, Boston, MA02115
| | - Fan Deng
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai200031, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Zengzhang Zheng
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai200031, China
- Shanghai Huashen Institute of Microbes and Infections, Shanghai200052, China
| | - Cong Jiang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai200433, China
| | - Rui Miao
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA02115
- Department of Pediatrics, Harvard Medical School, Boston, MA02115
| | - Zeyu Wu
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai200031, China
- University of Chinese Academy of Sciences, Beijing100049, China
| | - Peng Zhang
- Department of Thoracic Surgery, Shanghai Pulmonary Hospital, School of Medicine, Tongji University, Shanghai200433, China
| | - Youdong Pan
- Department of Dermatology, Brigham and Women’s Hospital, Boston, MA02115
- Harvard Skin Disease Research Center, Harvard Medical School, Boston, MA02115
| | - Judy Lieberman
- Program in Cellular and Molecular Medicine, Boston Children’s Hospital, Boston, MA02115
- Department of Pediatrics, Harvard Medical School, Boston, MA02115
| | - Xing Liu
- The Center for Microbes, Development and Health, Key Laboratory of Molecular Virology and Immunology, Institut Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai200031, China
- Shanghai Huashen Institute of Microbes and Infections, Shanghai200052, China
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Dang W, Meng C, Wang J, Zhou D, Chen G, Li N. Exploration of the Binding Modes of Toll-Like Receptor 4 Competitive Inhibitors: A Combined Ligand-Based and Target-Based Approach. ChemMedChem 2023; 18:e202200690. [PMID: 36651317 DOI: 10.1002/cmdc.202200690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 01/14/2023] [Accepted: 01/17/2023] [Indexed: 01/19/2023]
Abstract
The interactions of Toll-like receptor 4 (TLR4) with competitive inhibitors were investigated by a combined ligand-based and target-based approach. Firstly, the ligand-based pharmacophore model of the reported TLR4 inhibitors was constructed by utilizing the common feature method, which included three hydrophobic groups and a hydrogen bond receptor. The Schrödinger software suite glide module was used to dock inhibitors with proteins and verify the importance of these four interaction points from the target level. Then, molecular dynamics, alanine scanning mutagenesis, and binding free energy calculation were used to identify the key amino acids in the binding mode. In addition, blind docking proved that the TLR4 inhibitor does not bind to TLR4 itself like other TLR family proteins. Based on this, we also screened a class of sesquiterpene coumarins which possibly have TLR4 inhibitory activity and will conduct a detailed study later. Together, this study revealed the interactions between TLR4 protein and its competitive inhibitors, which shed light on better access for developing its novel inhibitors.
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Affiliation(s)
- Wen Dang
- School of Traditional Chinese Materia Medica, Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang City, Shenyang Pharmaceutical University, Shenyang, 110016, P.R. China
| | - Churen Meng
- School of Traditional Chinese Materia Medica, Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang City, Shenyang Pharmaceutical University, Shenyang, 110016, P.R. China
| | - Jian Wang
- Key Laboratory of Structure-Based Drug Design & Discovery of Ministry of Education, School of Pharmaceutical Engineering, Shenyang Pharmaceutical University, 103 Wenhua Road, Shenhe District, Shenyang, 110016, PR China
| | - Di Zhou
- School of Traditional Chinese Materia Medica, Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang City, Shenyang Pharmaceutical University, Shenyang, 110016, P.R. China
| | - Gang Chen
- School of Traditional Chinese Materia Medica, Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang City, Shenyang Pharmaceutical University, Shenyang, 110016, P.R. China
| | - Ning Li
- School of Traditional Chinese Materia Medica, Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang City, Shenyang Pharmaceutical University, Shenyang, 110016, P.R. China
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Velez-Negron YI, Simbaña-Carrera LL, Soto-Ramos CM, Medina O, Dinkel E, Hardy C, Rivera-Vargas LI, Ramos-Sepulveda L. First Report of Bacterial Pineapple Heart Rot Caused by Dickeya zeae in Puerto Rico. Plant Dis 2022; 107:210. [PMID: 35536215 DOI: 10.1094/pdis-01-22-0174-pdn] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In Puerto Rico, the agricultural production of pineapple (Ananas comosus (L.) Merr.) comprises nearly 5,000 tons harvested annually from over 250 ha (USDA 2018). With an annual income of approximately $3 million USD, pineapple ranks fourth in importance among Puerto Rican crops (USDA 2018). Recently, the pineapple industry on the island underwent a change from growing a local cultivar known as "Cabezona" to cultivar MD2, introduced from Hawaii around 1996 (SEA 2015), because this cultivar produces fruit more than once during a single growing season. In August 2018 (when the rainy season normally starts in Puerto Rico), soft rot symptoms appeared at commercial fields in Manatí (WGS 84 Lat 18.42694, Lng -66.44779) and persisted through 2019. Symptoms observed in the field included foliar water-soaked lesions with gas-filled blisters, especially at the base of the leaf. Leaves exhibited brown discoloration and a fetid odor (rot) at the basal portion of the plant. Finally, leaves collapsed at the center of the pineapple crown, effectively killing the apex and preventing the fruit from developing. Disease incidence ranged from 25% to 40% depending on the weather and season; when there was more rain, there was higher disease incidence. Symptomatic leaves were collected in February 2019, disinfected with 70% ethanol, and rinsed with sterile distilled water. Tissue sections (5mm2) were placed in nutrient agar. Bacterial colony-forming units (CFU) were a translucent cream color, circular, with a flat convex surface and wavy edge. Biochemical analysis showed that bacteria were Gram-negative, oxidase positive, catalase positive, and facultatively anaerobic. Pathogenicity was tested on leaves of one-and-a-half-year-old pineapple seedlings in humid chambers. Bacteria were grown on sterile nutrient agar for 3 days at 25 ± 2°C. Inoculation assays (three replications) were performed using 1X108 CFU/ml of bacteria suspended in sterile water and applied with a cotton swab to leaves wounded with a needle. The inoculated tissue was incubated at 28°C and kept in a dark environment. Negative controls were inoculated with sterile water. Five days after inoculation, foliar water-soaked lesions were observed, followed by the formation of brown leaf tissue and gas-filled blisters, the same symptoms observed in the field. A partial DNA sequence of the 16S rRNA gene of the bacterial isolate and the re-isolated bacteria were amplified using primers 27F and 1492R (Lane et al. 1985) and sequenced. The isolate was determined to the genus Dickeya through a BLAST® search against sequences available in the database of the National Center for Biotechnology Information (NCBI). This partial 16S rRNA sequence of the bacterial isolate was deposited in GenBank® at NCBI (Accession no. MT672704). To determine the identity of the Dickeya species, we sequenced the genes dnaA, gyrB, dnaX, and recN (Marrero et al. 2013) for the bacterial isolate (GenBank accession nos. OM276852, OM276853, OM276854, and OM276855) and conducted a Multilocus Sequence Analysis including reference Dickeya sequences of Marrero et al., 2013. The Phylogenetic analysis (using WinClada) resolved the Puerto Rican isolate as belonging to a clade broadly ascribable to D. zeae, most closely related to strains isolated from earlier Hawaiian pineapple bacterial heart rot outbreaks. Dickeya zeae was responsible for bacterial heart rot of pineapple in Malaysia and was later reported as the causal agent for outbreaks in Costa Rica and Hawaii (Kaneshiro et al. 2008; Sueno et al. 2014; Ramachandran et al. 2015). D. zeae had not previously been reported as causing bacterial heart rot in pineapples in Puerto Rico and this study points to a close relationship with strains first detected in Hawaii and which should further be explored to determine the precise nature of this relationship. This information should facilitate the adoption of effective control measures for this disease on the island, promote more effective methods of preventing future introductions of pathogens, and encourage further investigations into the occurrence of D. zeae on the island.
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Affiliation(s)
- Yesenia I Velez-Negron
- The Ohio State University, 2647, Plant Pathology, 2021 Coffey Road, Columbus, Ohio, United States, 43210;
| | | | - Casiani M Soto-Ramos
- Texas A&M University, 14736, AgriLife Research and Extension Center, Lubbock, Texas, United States;
| | - Olivia Medina
- Millersville University of Pennsylvania, 5482, Biology, Millersville, Pennsylvania, United States;
| | | | - Christopher Hardy
- Millersville University of Pennsylvania, 5482, Biology, Millersville, Pennsylvania, United States;
| | - Lydia I Rivera-Vargas
- University of Puerto Rico Mayaguez, 16146, Department of Agro-Environmental Sciences, Mayaguez, Puerto Rico;
| | - Laura Ramos-Sepulveda
- Millersville University of Pennsylvania, 5482, Biology, Millersville, Pennsylvania, United States;
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Xiong Y, Yang J, Tong H, Zhu C, Pang Y. HMGB1 augments cognitive impairment in sepsis-associated encephalopathy by binding to MD-2 and promoting NLRP3-induced neuroinflammation. Psychogeriatrics 2022; 22:167-179. [PMID: 34931753 DOI: 10.1111/psyg.12794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 11/07/2021] [Accepted: 11/23/2021] [Indexed: 12/28/2022]
Abstract
BACKGROUND Sepsis-associated encephalopathy (SAE) always manifests with severe inflammatory symptoms and cognitive impairment. High mobility group box 1 (HMGB1) is a pro-inflammatory cytokine. In this study we investigated the role of HMGB1 in SAE. METHODS An SAE mouse model was established through cecal ligation and puncture surgery and then injected with adenovirus short hairpin RNA (Ad-sh)-HMGB1 or Ad-sh-myeloid differentiation protein (MD-2). The cognitive impairment and pathological injury in mice of different groups were evaluated using the Morris water maze experiment, Y-maze test, tail suspension test, fear conditioning test, and haematoxylin-eosin staining. The expressions of HMGB1 (fully reduced and disulfide (ds)HMGB1), MD-2, and NLRP3 in SAE mice were determined. Then, levels of inflammatory cytokines were measured. The binding relation between HMGB1 and MD-2 was predicted and certified. Additionally, MD-2 was downregulated to verify the role of the binding of HMGB1 and MD-2 in neuroinflammation and cognitive impairment in SAE. RESULTS Expressions of HMGB1, MD-2, NLRP3, and inflammatory cytokines were enhanced in the SAE mouse model, which were in parallel with impaired cognitive function. HMGB1 silencing resulted in downregulated NLRP3 expression and alleviated neuroinflammation and cognitive impairment in SAE mice. Mechanically, dsHMGB1 bound to MD-2 to activate NLRP3, thereby exacerbating neuroinflammation and cognitive impairment in SAE mice. The limited binding of HMGB1 and MD-2 downregulated NLRP3 expression to alleviate neuroinflammation and cognitive impairment in SAE mice. CONCLUSION HMGB1 was overexpressed in SAE, and dsHMGB1 bound to MD-2 to activate NLRP3 inflammasome, inducing neuroinflammation and cognitive impairment in SAE.
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Affiliation(s)
- Yanan Xiong
- Department of Emergency, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, P.R. China
| | - Jilin Yang
- Department of Emergency, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, P.R. China
| | - Haiyang Tong
- Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei, P.R. China
| | - Chenting Zhu
- Department of Emergency, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, P.R. China
| | - Yinhu Pang
- Department of Emergency, Shanghai Tongji Hospital, School of Medicine, Tongji University, Shanghai, P.R. China
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Ishii T, Murakami Y, Narita T, Nunokawa H, Miyake K, Nagase T, Yamashita N. Myeloid differentiation protein-2 has a protective role in house dust mite-mediated asthmatic characteristics with the proinflammatory regulation of airway epithelial cells and dendritic cells. Clin Exp Allergy 2021; 52:149-161. [PMID: 34418187 DOI: 10.1111/cea.14002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2021] [Accepted: 08/17/2021] [Indexed: 12/19/2022]
Abstract
BACKGROUND Myeloid differentiation protein-2 (MD-2) is a lipopolysaccharide-binding protein involved in lipopolysaccharide signalling via Toll-like receptor 4 (TLR4). TLR4 plays an essential role in HDM-mediated allergic airway inflammation. Moreover, MD-2 is structurally similar to Der f 2, a major allergen from house dust mite (HDM). OBJECTIVES We aimed to clarify the role of MD-2 in the pathogenesis of HDM-mediated allergic airway inflammation. METHODS Wild-type (WT), TLR4 knockout and MD-2 knockout mice were subjected to intranasal instillation of HDM extract, and asthmatic features were evaluated. We also evaluated gene sets regulated by MD-2 in HDM-treated airway epithelial cells and examined the function of dendritic cells from lymph nodes and from lungs. RESULTS Aggravated allergic airway inflammation with increased airway hyperresponsiveness was observed in MD-2 knockout mice compared with WT and TLR4 knockout mice. Global gene expression analysis revealed an MD-2 regulated proinflammatory response and reconstituted TLR4 signalling in airway epithelial cells. The ability of dendritic cells to evoke an allergic immune response was enhanced in MD-2 knockout mice. CONCLUSIONS & CLINICAL RELEVANCE MD-2 plays a protective role in HDM-induced airway allergy with the proinflammatory regulation of airway epithelial cells and dendritic cells. MD-2 may serve as a therapeutic target in the treatment of asthma.
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Affiliation(s)
- Takashi Ishii
- Department of Pharmacotherapy, Research Institute of Pharmaceutical Sciences, Musashino University, Tokyo, Japan.,Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yusuke Murakami
- Department of Pharmacotherapy, Research Institute of Pharmaceutical Sciences, Musashino University, Tokyo, Japan
| | - Tomoya Narita
- Department of Pharmacotherapy, Research Institute of Pharmaceutical Sciences, Musashino University, Tokyo, Japan
| | - Hiroki Nunokawa
- Department of Pharmacotherapy, Research Institute of Pharmaceutical Sciences, Musashino University, Tokyo, Japan
| | - Kensuke Miyake
- Division of Innate Immunity, Department of Microbiology and immunology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Takahide Nagase
- Department of Respiratory Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Naomi Yamashita
- Department of Pharmacotherapy, Research Institute of Pharmaceutical Sciences, Musashino University, Tokyo, Japan
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Zhang R, Li X, Zhang J, Li Y, Wang Y, Song Y, Ren F, Yi H, Deng X, Zhong Y, Cao Y, Strand MR, Yu XQ, Yang W. Toll9 from Bombyx mori functions as a pattern recognition receptor that shares features with Toll-like receptor 4 from mammals. Proc Natl Acad Sci U S A 2021; 118:e2103021118. [PMID: 33963082 DOI: 10.1073/pnas.2103021118] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Toll/Toll-like receptors (TLRs) are key regulators of the innate immune system in both invertebrates and vertebrates. However, while mammalian TLRs directly recognize pathogen-associated molecular patterns, the insect Toll pathway is thought to be primarily activated by binding Spätzle cytokines that are processed from inactive precursors in response to microbial infection. Phylogenetic and structural data generated in this study supported earlier results showing that Toll9 members differ from other insect Tolls by clustering with the mammalian TLR4 group, which recognizes lipopolysaccharide (LPS) through interaction with myeloid differentiation-2 (MD-2)-like proteins. Functional experiments showed that BmToll9 from the silkmoth Bombyx mori also recognized LPS through interaction with two MD-2-like proteins, previously named BmEsr16 and BmPP, that we refer to in this study as BmMD-2A and BmMD-2B, respectively. A chimeric BmToll9-TLR4 receptor consisting of the BmToll9 ectodomain and mouse TLR4 transmembrane and Toll/interleukin-1 (TIR) domains also activated LPS-induced release of inflammatory factors in murine cells but only in the presence of BmMD-2A or BmMD-2B. Overall, our results indicate that BmToll9 is a pattern recognition receptor for LPS that shares conserved features with the mammalian TLR4-MD-2-LPS pathway.
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Qi W, Chen Y, Sun S, Xu X, Zhan J, Yan Z, Shang P, Pan X, Liu H. Inhibiting TLR4 signaling by linarin for preventing inflammatory response in osteoarthritis. Aging (Albany NY) 2021; 13:5369-5382. [PMID: 33536347 PMCID: PMC7950270 DOI: 10.18632/aging.202469] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2020] [Accepted: 11/30/2020] [Indexed: 02/06/2023]
Abstract
Osteoarthritis (OA) is one of the most common degenerative diseases, ultimately leading to long-term joint pain and severe articular malformation. Controlling local chronic inflammation is a crucial strategy for delaying OA development. Linarin is a natural flavonoid glycoside that is widely available in Compositae, Chrysanthemum indicum and Dendrocalamus and processes protective effects in several animal models. The purpose of our work was to study the protective effect of Linarin for OA. Cellular experiments data showed that Linarin suppressed lipopolysaccharide (LPS)-caused the overproduction of nitric oxide (NO), prostaglandin E2 (PGE2), interleukin-6 (IL-6) and tumour necrosis factor-alpha (TNF-α) in chondrocyte. In addition, LPS-stimulated expression of cyclooxygenase-2 (COX-2) and inducible nitric oxide nitrate (iNOS) was decreased by Linarin pre-treatment. Together, Linarin prevented the catabiosis of extracellular matrix caused by LPS. For mechanism, Linarin inhibited the formation of Toll-like receptor 4 (TLR4) / myeloid differentiation protein-2 (MD-2) dipolymer complex and subsequently intervened NF-κB activation. Our mouse DMM model further clarified the protection of Linarin in vivo. In summary, our results suggested that Linarin may be a potential effective agent for OA.
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Affiliation(s)
- Weihui Qi
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Yanlin Chen
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Shuaibo Sun
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Xinxian Xu
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Jingdi Zhan
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Zijian Yan
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Ping Shang
- Department of Rehabilitation, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Xiaoyun Pan
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
| | - Haixiao Liu
- Department of Orthopedic Surgery, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, Wenzhou 325027, China
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Belcher JD, Zhang P, Nguyen J, Kiser ZM, Nath KA, Hu J, Trent JO, Vercellotti GM. Identification of a Heme Activation Site on the MD-2/TLR4 Complex. Front Immunol 2020; 11:1370. [PMID: 32695117 PMCID: PMC7338675 DOI: 10.3389/fimmu.2020.01370] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 05/28/2020] [Indexed: 11/13/2022] Open
Abstract
Myeloid differentiation factor-2 (MD-2) binds lipopolysaccharide (LPS) and initiates toll-like receptor-4 (TLR4) pro-inflammatory signaling. Heme also activates TLR4 signaling, but it is unknown if heme interacts with MD-2. Therefore, we examined MD-2 for a potential heme activation site. Heme-agarose and biotin-heme/streptavidin-agarose pulled down recombinant MD-2, which was inhibited by excess free heme. UV/visible spectroscopy confirmed MD-2-heme binding. To determine whether MD-2 was required for heme-mediated TLR4 signaling, HEK293 cells were transfected with MD-2, TLR4, CD14, and an NF-κB luciferase reporter, and then stimulated with heme or LPS. Heme or LPS treatment elicited robust reporter activity. Absence of MD-2, TLR4 or CD14 plasmid abolished NF-κB reporter responses to heme or LPS. In silico analysis identified two potential heme docking sites on MD-2 near conserved amino acids W23/S33/Y34 and Y36/C37/I44. Heme-induced NF-κB activity was reduced by 39 and 78% in HEK293 cells transfected with MD-2 mutants W23A and Y34A, respectively, compared to WT-MD-2. NF-κB activation by LPS was not affected by the same mutants. Biotinyl-heme/streptavidin-agarose pulled down 68% less W23A and 80% less W23A/S33A/Y34A mutant MD-2 than WT-MD-2. In contrast, at the Y36/C37/I44 MD-2 site, heme-induced NF-κB activity was significantly increased by mutants Y36A (191% of WT-MD-2) and unchanged by mutants C37A and I44A (95 and 92%, respectively, of WT-MD-2). In conclusion, these data suggest that heme binds and activates TLR4 signaling at amino acids W23 and Y34 on MD-2.
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Affiliation(s)
- John D Belcher
- Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Ping Zhang
- Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Julia Nguyen
- Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Zachary M Kiser
- Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Karl A Nath
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, United States
| | - Jianjun Hu
- College of Engineering and Computing, University of South Carolina, Columbia, SC, United States
| | - John O Trent
- Departments of Medicine, and Biochemistry and Molecular Genetics, James Graham Brown Cancer Center, University of Louisville, Louisville, KY, United States
| | - Gregory M Vercellotti
- Division of Hematology, Oncology and Transplantation, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
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Giordano NP, Cian MB, Dalebroux ZD. Outer Membrane Lipid Secretion and the Innate Immune Response to Gram-Negative Bacteria. Infect Immun 2020; 88:e00920-19. [PMID: 32253250 DOI: 10.1128/IAI.00920-19] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The outer membrane (OM) of Gram-negative bacteria is an asymmetric lipid bilayer that consists of inner leaflet phospholipids and outer leaflet lipopolysaccharides (LPS). The asymmetric character and unique biochemistry of LPS molecules contribute to the OM's ability to function as a molecular permeability barrier that protects the bacterium against hazards in the environment. Assembly and regulation of the OM have been extensively studied for understanding mechanisms of antibiotic resistance and bacterial defense against host immunity; however, there is little knowledge on how Gram-negative bacteria release their OMs into their environment to manipulate their hosts. Discoveries in bacterial lipid trafficking, OM lipid homeostasis, and host recognition of microbial patterns have shed new light on how microbes secrete OM vesicles (OMVs) to influence inflammation, cell death, and disease pathogenesis. Pathogens release OMVs that contain phospholipids, like cardiolipins, and components of LPS molecules, like lipid A endotoxins. These multiacylated lipid amphiphiles are molecular patterns that are differentially detected by host receptors like the Toll-like receptor 4/myeloid differentiation factor 2 complex (TLR4/MD-2), mouse caspase-11, and human caspases 4 and 5. We discuss how lipid ligands on OMVs engage these pattern recognition receptors on the membranes and in the cytosol of mammalian cells. We then detail how bacteria regulate OM lipid asymmetry, negative membrane curvature, and the phospholipid-to-LPS ratio to control OMV formation. The goal is to highlight intersections between OM lipid regulation and host immunity and to provide working models for how bacterial lipids influence vesicle formation.
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Lozano-Aponte J, Scior T, Ambrosio FNM, González-Melchor M, Alexander C. Exploring electrostatic patterns of human, murine, equine and canine TLR4/ MD-2 receptors. Innate Immun 2019; 26:364-380. [PMID: 31874581 PMCID: PMC7903528 DOI: 10.1177/1753425919894628] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Electrostatic interactions between phosphate anions and Toll-like receptor 4 / Myeloid differentiation factor-2 (TLR4/MD-2) protein complexes of human, murine, equine and canine species were computed. Such knowledge can provide mechanistic information about recognising LPS-like ligands, since anionic phosphate groups belong to the structural features of LPS with their diphosphorylated diglucosamine backbone. Sequence composition analyses, electrostatic interaction potentials and docked energies as well as molecular dynamics studies evaluated the phosphate interactions within the triangular LPS binding site (wedge). According to electrostatic analyses, human, horse and dog wedges possess phosphate-binding sites with indistinct positive and negative charge distributions, but the murine wedge shows a unique strong negative net charge at the site where antagonists bind in other species (Pan). Docking of a phosphate mono-anion (probe) confirmed its repulsion at this Pan site, but the Pag site of the murine wedge attracted the probe. It is occupied by phosphate groups of agonists in other species (Pag). Molecular dynamics trajectories show a variable degree of random walk across the wedges, that is, not following electrostatic preferences (neither Pag nor Pan). In summary, two opposing electrostatic patterns exist -murine versus human, equine and canine species - all of which reflect the potential dual activity mode of under-acylated ligands such as lipid IVA.
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Affiliation(s)
- Jorge Lozano-Aponte
- Tecnológico de Monterrey, Escuela de Ingeniería y Ciencias, Campus Puebla, Mexico
| | - Thomas Scior
- Departamento de Farmacia, Benemérita Universidad Autónoma de Puebla, Mexico
| | | | | | - Christian Alexander
- Division of Cellular Microbiology, Research Center Borstel- Leibniz Lung Center, Germany
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11
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Zhang X, Peng Y, Grace PM, Metcalf MD, Kwilasz AJ, Wang Y, Zhang T, Wu S, Selfridge BR, Portoghese PS, Rice KC, Watkins LR, Hutchinson MR, Wang X. Stereochemistry and innate immune recognition: (+)-norbinaltorphimine targets myeloid differentiation protein 2 and inhibits toll-like receptor 4 signaling. FASEB J 2019; 33:9577-9587. [PMID: 31162938 PMCID: PMC6988860 DOI: 10.1096/fj.201900173rrr] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 04/29/2019] [Indexed: 02/06/2023]
Abstract
Deregulation of innate immune TLR4 signaling contributes to various diseases including neuropathic pain and drug addiction. Naltrexone is one of the rare TLR4 antagonists with good blood-brain barrier permeability and showing no stereoselectivity for TLR4. By linking 2 naltrexone units through a rigid pyrrole spacer, the bivalent ligand norbinaltorphimine was formed. Interestingly, (+)-norbinaltorphimine [(+)-1] showed ∼25 times better TLR4 antagonist activity than naltrexone in microglial BV-2 cell line, whereas (-)-norbinaltorphimine [(-)-1] lost TLR4 activity. The enantioselectivity of norbinaltorphimine was further confirmed in primary microglia, astrocytes, and macrophages. The activities of meso isomer of norbinaltorphimine and the molecular dynamic simulation results demonstrate that the stereochemistry of (+)-1 is derived from the (+)-naltrexone pharmacophore. Moreover, (+)-1 significantly increased and prolonged morphine analgesia in vivo. The efficacy of (+)-1 is long lasting. This is the first report showing enantioselective modulation of the innate immune TLR signaling.-Zhang, X., Peng, Y., Grace, P. M., Metcalf, M. D., Kwilasz, A. J., Wang, Y., Zhang, T., Wu, S., Selfridge, B. R., Portoghese, P. S., Rice, K. C., Watkins, L. R., Hutchinson, M. R., Wang, X. Stereochemistry and innate immune recognition: (+)-norbinaltorphimine targets myeloid differentiation protein 2 and inhibits toll-like receptor 4 signaling.
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Affiliation(s)
- Xiaozheng Zhang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yinghua Peng
- State Key Laboratory for Molecular Biology of Special Economic Animals, Institute of Special Wild Economic Animals and Plants, Chinese Academy of Agricultural Sciences, Changchun, China
| | - Peter M. Grace
- Department of Psychology and Neuroscience, Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Matthew D. Metcalf
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Andrew J. Kwilasz
- Department of Psychology and Neuroscience, Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Yibo Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
| | - Tianshu Zhang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
| | - Siru Wu
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
| | - Brandon R. Selfridge
- Drug Design and Synthesis Section, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland, USA
| | - Philip S. Portoghese
- Department of Medicinal Chemistry, College of Pharmacy, University of Minnesota, Minneapolis, Minnesota, USA
| | - Kenner C. Rice
- Drug Design and Synthesis Section, National Institute on Drug Abuse and National Institute on Alcohol Abuse and Alcoholism, Bethesda, Maryland, USA
| | - Linda R. Watkins
- Department of Psychology and Neuroscience, Center for Neuroscience, University of Colorado at Boulder, Boulder, Colorado, USA
| | - Mark R. Hutchinson
- Discipline of Physiology, Adelaide Medical School and Australian Research Council (ARC) Centre of Excellence for Nanoscale Biophotonics, University of Adelaide, South Australia, Australia
| | - Xiaohui Wang
- Laboratory of Chemical Biology, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun, China
- State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing, China
- University of Chinese Academy of Sciences, Beijing, China
- Department of Applied Chemistry and Engineering, University of Science and Technology of China, Hefei, China
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12
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Li N, Xu H, Ou Y, Feng Z, Zhang Q, Zhu Q, Cai Z. LPS-induced CXCR7 expression promotes gastric Cancer proliferation and migration via the TLR4/ MD-2 pathway. Diagn Pathol 2019; 14:3. [PMID: 30636642 PMCID: PMC6330400 DOI: 10.1186/s13000-019-0780-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 01/04/2019] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Lipopolysaccharide (LPS) from Helicobacter pylori (HP) plays an important role in gastric cancer occurrence and development. Toll-like receptor 4 (TLR4) and myeloid differential protein-2 (MD-2) are also reported to be involved in gastric cancer cell proliferation and invasion. CXC chemokine receptor 7 (CXCR7), a second receptor for CXCL12, has been detected in multiple types of tumor tissues. Nevertheless, the biological function and regulation of CXCR7 and its relationship with TLR4 and MD-2 in gastric cancer are not completely understood and therefore warrant further study. METHODS CXCR7 expression was examined in 150 gastric cancer tissues using immunohistochemistry (IHC). RT-PCR and western blotting were used to detect CXCR7 expression in several gastric cancer cell lines (SGC7901, AGS, MGC-803, MKN-45 and BGC823). shRNAs were designed using a pGPU6/GFP/Neo vector. A CCK-8 assay was used to assess cell proliferation, and transwell assays were performed to assess cell migration. In addition, a gastric cancer xenograft model was generated. RESULTS The LPS-TLR4-MD-2 pathway elevates CXCR7 expression in SGC7901 cells, and TLR4/MD-2-mediated increases in CXCR7 levels modulate the proliferation and migration of tumor cells. Knockdown of TLR4 and MD-2 demonstrated that both are essential for LPS-induced CXCR7 expression, which in turn is responsible for LPS-induced SGC7901 cell proliferation and migration. Moreover, higher TLR4, MD-2 and CXCR7 expression was detected in gastric cancer tissues than in paracancerous normal control tissues. The expression levels of TLR4, MD-2 and CXCR7 were closely related to gastric cancer TNM stage and lymph node metastasis. In an animal model, significant differences in CXCR7 expression in tumor masses were observed between the control group and experimental group. CONCLUSIONS The results of this study indicate that CXCR7 plays an important role in gastric cancer progression via inflammatory mechanisms, suggesting that CXCR7 could provide a basis for the development and clinical application of a targeted drug for gastric cancer.
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Affiliation(s)
- Nan Li
- Department of Pathology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China.,Department of Pathology, Bengbu Medical College, Bengbu, China
| | - Huanbai Xu
- Department of Endocrinology and Metabolism, Shanghai Jiaotong University Affiliated First People's Hospital, Shanghai, China
| | - Yurong Ou
- Department of Pathology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China.,Department of Pathology, Bengbu Medical College, Bengbu, China
| | - Zhenzhong Feng
- Department of Pathology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China.,Department of Pathology, Bengbu Medical College, Bengbu, China
| | - Qiong Zhang
- Department of Pathology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China.,Department of Pathology, Bengbu Medical College, Bengbu, China
| | - Qing Zhu
- Department of Pathology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China.,Department of Pathology, Bengbu Medical College, Bengbu, China
| | - Zhaogen Cai
- Department of Pathology, The First Affiliated Hospital of Bengbu Medical College, Bengbu, China. .,Department of Pathology, Bengbu Medical College, Bengbu, China.
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13
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Zhang RN, Ren FF, Zhou CB, Xu JF, Yi HY, Ye MQ, Deng XJ, Cao Y, Yu XQ, Yang WY. An ML protein from the silkworm Bombyx mori may function as a key accessory protein for lipopolysaccharide signaling. Dev Comp Immunol 2018; 88:94-103. [PMID: 30009928 DOI: 10.1016/j.dci.2018.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Revised: 07/11/2018] [Accepted: 07/12/2018] [Indexed: 06/08/2023]
Abstract
Lipopolysaccharide (LPS) is a common component of the outermost cell wall in Gram-negative bacteria. In mammals, LPS serves as an endotoxin that can be recognized by a receptor complex of TLR4 (Toll-like receptor 4) and MD-2 (myeloid differentiation-2) and subsequently induce a strong immune response to signal the release of tumor necrosis factor (TNF). In Drosophila melanogaster, no receptors for LPS have been identified, and LPS cannot activate immune responses. Here, we report a protein, BmEsr16, which contains an ML (MD-2-related lipid-recognition) domain, may function as an LPS receptor in the silkworm Bombyx mori. We showed that antibacterial activity in the hemolymph of B. mori larvae was induced by Escherichia coli, peptidoglycan (PGN) and LPS and that the expression of antimicrobial peptide genes was also induced by LPS. Furthermore, both the expression of BmEsr16 mRNA in the fat body and the expression of BmEsr16 protein in the hemolymph were induced by LPS. Recombinant BmEsr16 bound to LPS and lipid A, as well as to PGN, lipoteichoic acid, but not to laminarin or mannan. More importantly, LPS-induced immune responses in the hemolymph of B. mori larvae were blocked when the endogenous BmEsr16 protein was neutralized by polyclonal antibody specific to BmEsr16. Our results suggest that BmEsr16 may function as a key accessory protein for LPS signaling in B. mori.
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Affiliation(s)
- Ruo-Nan Zhang
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Fei-Fei Ren
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Cheng-Bo Zhou
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Jun-Feng Xu
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Hui-Yu Yi
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Ming-Qiang Ye
- The Sericultural and Agri-Food Research Institute of the Guangdong Academy of Agricultural Sciences, Guangzhou 510642, China
| | - Xiao-Juan Deng
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Yang Cao
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiao-Qiang Yu
- Guangzhou Key Laboratory of Insect Development Regulation and Application Research, Institute of Insect Science and Technology & School of Life Sciences, South China Normal University, Guangzhou 510631, China.
| | - Wan-Ying Yang
- Laboratory of Insect Molecular Biology and Biotechnology, Guangdong Provincial Key Laboratory of Agro-animal Genomics and Molecular Breeding, College of Animal Science, South China Agricultural University, Guangzhou 510642, China.
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14
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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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15
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Abstract
Activation or inhibition of TLR4 by small molecules will provide in the next few years a new generation of therapeutics. TLR4 stimulation (agonism) by high-affinity ligands mimicking lipid A gave vaccine adjuvants with improved specificity and efficacy that have been licensed and entered into the market. TLR4 inhibition (antagonism) prevents cytokine production at a very early stage; this is in principle a more efficient method to block inflammatory diseases compared to cytokines neutralization by antibodies. Advances in TLR4 modulation by drug-like small molecules achieved in the last years are reviewed. Recently discovered TLR4 agonists and antagonists of natural and synthetic origin are presented, and their mechanism of action and structure-activity relationship are discussed.
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16
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Kuzmich NN, Sivak KV, Chubarev VN, Porozov YB, Savateeva-Lyubimova TN, Peri F. TLR4 Signaling Pathway Modulators as Potential Therapeutics in Inflammation and Sepsis. Vaccines (Basel) 2017; 5:E34. [PMID: 28976923 DOI: 10.3390/vaccines5040034] [Citation(s) in RCA: 314] [Impact Index Per Article: 44.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 09/29/2017] [Accepted: 10/01/2017] [Indexed: 02/06/2023] Open
Abstract
Toll-Like Receptor 4 (TLR4) signal pathway plays an important role in initiating the innate immune response and its activation by bacterial endotoxin is responsible for chronic and acute inflammatory disorders that are becoming more and more frequent in developed countries. Modulation of the TLR4 pathway is a potential strategy to specifically target these pathologies. Among the diseases caused by TLR4 abnormal activation by bacterial endotoxin, sepsis is the most dangerous one because it is a life-threatening acute system inflammatory condition that still lacks specific pharmacological treatment. Here, we review molecules at a preclinical or clinical phase of development, that are active in inhibiting the TLR4-MyD88 and TLR4-TRIF pathways in animal models. These are low-molecular weight compounds of natural and synthetic origin that can be considered leads for drug development. The results of in vivo studies in the sepsis model and the mechanisms of action of drug leads are presented and critically discussed, evidencing the differences in treatment results from rodents to humans.
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17
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Tsukamoto H, Yamagata Y, Ukai I, Takeuchi S, Okubo M, Kobayashi Y, Kozakai S, Kubota K, Numasaki M, Kanemitsu Y, Matsumoto Y, Tomioka Y. An inhibitory epitope of human Toll-like receptor 4 resides on leucine-rich repeat 13 and is recognized by a monoclonal antibody. FEBS Lett 2017; 591:2406-2416. [PMID: 28741733 DOI: 10.1002/1873-3468.12768] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 07/15/2017] [Accepted: 07/23/2017] [Indexed: 12/16/2022]
Abstract
Lipopolysaccharide (LPS)-induced activation of Toll-like receptor 4 (TLR4) elicits the innate immune response and can trigger septic shock if excessive. Two antibodies (HT4 and HT52) inhibit LPS-induced human TLR4 activation via novel LPS binding-independent mechanisms. The HT52 epitope resides on leucine-rich repeat 2 (LRR2) and is a feature of many inhibitory antibodies; antigen specificity of HT4 does not reside in LRR2. Here, we identified an HT4 epitope on LRR13 located close to the TLR4 dimerization interface that plays a role in NFκB activation. HT4 and HT52 mutually enhanced TLR4 inhibition. LRR13 is a novel inhibitory epitope and may be useful for developing anti-TLR4 antibodies. Combination therapy with LRR2 and LRR13 may effectively inhibit TLR4 activation.
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Affiliation(s)
- Hiroki Tsukamoto
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yuki Yamagata
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Ippo Ukai
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Shino Takeuchi
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Misaki Okubo
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yohei Kobayashi
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Sao Kozakai
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Kanae Kubota
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Muneo Numasaki
- Department of Geriatrics and Gerontology, Institute of Development, Aging and Cancer, Tohoku University, Sendai, Japan
| | - Yoshitomi Kanemitsu
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yotaro Matsumoto
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
| | - Yoshihisa Tomioka
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, Sendai, Japan
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18
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Al-Anazi MR, Nazir N, Abdo AA, Sanai FM, Alkahtani S, Alarifi S, Alkahtane AA, Al-Yahya H, Ali D, Alessia MS, Al-Ahdal MN, Al-Qahtani AA. Genetic variations of NOD2 and MD2 genes in hepatitis B virus infection. Saudi J Biol Sci 2016; 26:270-280. [PMID: 31485165 PMCID: PMC6717085 DOI: 10.1016/j.sjbs.2016.11.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/09/2016] [Accepted: 11/09/2016] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVES Nucleotide oligomerization domain 2 (NOD2) and myeloid differentiation protein 2 (MD-2) have crucial roles in the innate immune system. NOD2 is a member of the NOD-like receptor (NLR) family of pattern recognition receptors (PRRs), while MD-2 is a co-receptor for Toll-like receptor 4 (TLR4), which comprises another group of PRRs. Genetic variations in the NOD2 and MD-2 genes may be susceptibility factors to viral pathogens including hepatitis B virus (HBV). We investigated whether polymorphisms at NOD2 (rs2066845 and rs2066844) or at MD-2 (rs6472812 and rs11466004) were associated with susceptibility to HBV infection and advancement to related liver complications in a Saudi Arabian population. Methods: A total of 786 HBV-infected patients and 600 healthy uninfected controls were analyzed in the present study. HBV-infected patients were categorized into three groups based on the clinical stage of the infection: inactive HBV carriers, active HBV carriers, and patients with liver cirrhosis + hepatocellular carcinoma (HCC). Results: All four SNPs were significantly associated with susceptibility to HBV infection although none of the SNPs tested in NOD2 and MD-2 were significantly associated with persistence of HBV infection. We found that HBV-infected patients that were homozygous CC for rs2066845 in the NOD2 gene were at a significantly increased risk of progression to HBV-related liver complications (Odds Ratio = 7.443 and P = 0.044). Furthermore, haplotype analysis found that the rs2066844-rs2066845 C-G and T-G haplotypes at the NOD2 gene and four rs6472812-rs11466004 haplotypes (G-C, G-T, A-C, and A-T) at the MD-2 gene were significantly associated with HBV infection in the affected cohort compared to those found in our control group. Conclusion: We found that the single nucleotide polymorphisms rs2066844 and rs2066845 at NOD2 and rs6472812 and rs11466004 at MD-2 were associated with susceptibility to HBV infection in a Saudi population.
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Affiliation(s)
- Mashael R Al-Anazi
- Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Nyla Nazir
- Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia
| | - Ayman A Abdo
- Section of Gastroenterology, Department of Medicine, College of Medicine, King Saud University, Riyadh, Saudi Arabia.,Liver Disease Research Center, King Saud University, Riyadh, Saudi Arabia
| | - Faisal M Sanai
- Gastroenterology Unit, Department of Medicine, King Abdulaziz Medical City, Jeddah, Saudi Arabia.,Liver Disease Research Center, King Saud University, Riyadh, Saudi Arabia
| | - Saad Alkahtani
- Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Saud Alarifi
- Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Abdullah A Alkahtane
- Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Hamad Al-Yahya
- Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Daoud Ali
- Department of Zoology, Science College, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed S Alessia
- Department of Biology, Science College, AI-Imam Muhammad Ibn Saud Islamic University, Riyadh, Saudi Arabia
| | - Mohammed N Al-Ahdal
- Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia.,Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia
| | - Ahmed A Al-Qahtani
- Department of Infection and Immunity, Research Center, King Faisal Specialist Hospital & Research Center, Riyadh, Saudi Arabia.,Department of Microbiology and Immunology, Alfaisal University School of Medicine, Riyadh, Saudi Arabia
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19
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Choi SH, Sviridov D, Miller YI. Oxidized cholesteryl esters and inflammation. Biochim Biophys Acta Mol Cell Biol Lipids 2016; 1862:393-397. [PMID: 27368140 DOI: 10.1016/j.bbalip.2016.06.020] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2016] [Revised: 06/08/2016] [Accepted: 06/24/2016] [Indexed: 11/30/2022]
Abstract
The oxidation hypothesis of atherosclerosis proposes that oxidized LDL is a major causative factor in the development of atherosclerosis. Although this hypothesis has received strong mechanistic support and many animal studies demonstrated profound atheroprotective effects of antioxidants, which reduce LDL oxidation, the results of human clinical trials with antioxidants were mainly negative, except in selected groups of patients with clearly increased systemic oxidative stress. We propose that even if reducing lipoprotein oxidation in humans might be difficult to achieve, deeper understanding of mechanisms by which oxidized LDL promotes atherosclerosis and targeting these specific mechanisms will offer novel approaches to treatment of cardiovascular disease. In this review article, we focus on oxidized cholesteryl esters (OxCE), which are a major component of minimally and extensively oxidized LDL and of human atherosclerotic lesions. OxCE and OxCE-protein covalent adducts induce profound biological effects. Among these effects, OxCE activate macrophages via toll-like receptor-4 (TLR4) and spleen tyrosine kinase and induce macropinocytosis resulting in lipid accumulation, generation of reactive oxygen species and secretion of inflammatory cytokines. Specific inhibition of OxCE-induced TLR4 activation, as well as blocking other inflammatory effects of OxCE, may offer novel treatments of atherosclerosis and cardiovascular disease. This article is part of a Special Issue entitled: Lipid modification and lipid peroxidation products in innate immunity and inflammation edited by Christoph J. Binder.
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Affiliation(s)
- Soo-Ho Choi
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Dmitri Sviridov
- Baker IDI Heart and Diabetes Institute, Melbourne, VIC 3004, Australia
| | - Yury I Miller
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093, USA.
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20
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Croasdell A, Sime PJ, Phipps RP. Resolvin D2 decreases TLR4 expression to mediate resolution in human monocytes. FASEB J 2016; 30:3181-93. [PMID: 27256622 DOI: 10.1096/fj.201600375r] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 05/23/2016] [Indexed: 12/26/2022]
Abstract
TLRs are critical for innate immunity, but excessive activation can lead to tissue damage and disease. Specialized proresolving mediators (SPMs), including resolvin D2 (RvD2), promote the active resolution of inflammation. How SPMs regulate early LPS signaling, including activation of TLR4, is unknown. We treated human THP-1 monocytic cells and primary human blood monocytes with RvD2 and LPS to evaluate modulation of TLRs. miRNA-146a overexpression and inhibition were used to dissect the mechanism of RvD2-mediated actions. We validated our studies using ELISAs for cytokines, PCR, Western blot analysis, and flow cytometry. Cells treated with 0.1% ethanol (control for RvD2) and/or PBS (control for LPS), and control microRNA mimics and inhibitors were used as controls. RvD2 reduced LPS-induced cytokines and TLR4 expression in human monocytes by up to 75%. In THP-1 cells, RvD2 reduced expression of TLR4, lymphocyte antigen 96 (MD-2), and downstream signals (MyD88, TRIF, and TAK1). These effects were partially mediated through RvD2 induction of microRNA-146a, and RvD2's actions were blocked by microRNA-146a inhibition. These new findings reveal the ability of RvD2 to reduce TLR4 expression and attenuate LPS-induced inflammation, providing a new area of SPM activity to investigate in this major area of therapeutic research.-Croasdell, A., Sime, P. J., Phipps, R. P. Resolvin D2 decreases TLR4 expression to mediate resolution in human monocytes.
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Affiliation(s)
- Amanda Croasdell
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; and
| | - Patricia J Sime
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
| | - Richard P Phipps
- Department of Environmental Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA; and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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21
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Ciaramelli C, Calabrese V, Sestito SE, Pérez-Regidor L, Klett J, Oblak A, Jerala R, Piazza M, Martín-Santamaría S, Peri F. Glycolipid-based TLR4 Modulators and Fluorescent Probes: Rational Design, Synthesis, and Biological Properties. Chem Biol Drug Des 2016; 88:217-29. [PMID: 26896420 DOI: 10.1111/cbdd.12749] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 12/08/2015] [Accepted: 02/08/2016] [Indexed: 12/13/2022]
Abstract
The cationic glycolipid IAXO-102, a potent TLR4 antagonist targeting both MD-2 and CD14 co-receptors, has been used as scaffold to design new potential TLR4 modulators and fluorescent labels for the TLR4 receptor complex (membrane TLR4.MD-2 dimer and CD14). The primary amino group of IAXO-102, not involved in direct interaction with MD-2 and CD14 receptors, has been exploited to covalently attach a fluorescein (molecules 1 and 2) or to link two molecules of IAXO-102 through diamine and diammonium spacers, obtaining 'dimeric' molecules 3 and 4. The structure-based rational design of compounds 1-4 was guided by the optimization of MD-2 and CD14 binding. Compounds 1 and 2 inhibited TLR4 activation, in a concentration-dependent manner, and signaling in HEK-Blue TLR4 cells. The fluorescent labeling of murine macrophages by molecule 1 was inhibited by LPS and was also abrogated when cell surface proteins were digested by trypsin, thus suggesting an interaction of fluorescent probe 1 with membrane proteins of the TLR4 receptor system.
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Affiliation(s)
- Carlotta Ciaramelli
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, 20126, Milano, Italy
| | - Valentina Calabrese
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, 20126, Milano, Italy
| | - Stefania E Sestito
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, 20126, Milano, Italy
| | - Lucia Pérez-Regidor
- Department of Chemistry and Biochemistry, Universidad CEU San Pablo, 28668-Boadilla del Monte, Madrid, Spain.,Department of Chemical and Physical Biology, Center for Biological Research, CIB-CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Javier Klett
- Department of Chemistry and Biochemistry, Universidad CEU San Pablo, 28668-Boadilla del Monte, Madrid, Spain.,Department of Chemical and Physical Biology, Center for Biological Research, CIB-CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Alja Oblak
- Department of Biotechnology, National Institute of Chemistry Ljubljana and EN-FIST Center of Excellence, Hajdrihova 19, SI-1001, Ljubljana, Slovenia
| | - Roman Jerala
- Department of Biotechnology, National Institute of Chemistry Ljubljana and EN-FIST Center of Excellence, Hajdrihova 19, SI-1001, Ljubljana, Slovenia
| | - Matteo Piazza
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, 20126, Milano, Italy
| | - Sonsoles Martín-Santamaría
- Department of Chemistry and Biochemistry, Universidad CEU San Pablo, 28668-Boadilla del Monte, Madrid, Spain.,Department of Chemical and Physical Biology, Center for Biological Research, CIB-CSIC, Ramiro de Maeztu 9, 28040, Madrid, Spain
| | - Francesco Peri
- Department of Biotechnology and Biosciences, University of Milano-Bicocca, Piazza della Scienza, 2, 20126, Milano, Italy
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22
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Abstract
Cholesterol is a structural component of cellular membranes, which is transported from liver to peripheral cells in the form of cholesterol esters (CE), residing in the hydrophobic core of low-density lipoprotein. Oxidized CE (OxCE) is often found in plasma and in atherosclerotic lesions of subjects with cardiovascular disease. Our earlier studies have demonstrated that OxCE activates inflammatory responses in macrophages via toll-like receptor-4 (TLR4). Here we demonstrate that cholesterol binds to myeloid differentiation-2 (MD-2), a TLR4 ancillary molecule, which is a binding receptor for bacterial lipopolysaccharide (LPS) and is indispensable for LPS-induced TLR4 dimerization and signaling. Cholesterol binding to MD-2 was competed by LPS and by OxCE-modified BSA. Furthermore, soluble MD-2 in human plasma and MD-2 in mouse atherosclerotic lesions carried cholesterol, the finding supporting the biological significance of MD-2 cholesterol binding. These results help understand the molecular basis of TLR4 activation by OxCE and mechanisms of chronic inflammation in atherosclerosis.
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Affiliation(s)
- Soo-Ho Choi
- Department of Medicine, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Jungsu Kim
- Department of Medicine, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Ayelet Gonen
- Department of Medicine, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Suganya Viriyakosol
- Department of Medicine, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA
| | - Yury I Miller
- Department of Medicine, University of California, 9500 Gilman Drive, La Jolla, San Diego, CA 92093, USA.
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23
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Mattis DM, Chervin AS, Ranoa DR, Kelley SL, Tapping RI, Kranz DM. Studies of the TLR4-associated protein MD-2 using yeast-display and mutational analyses. Mol Immunol 2015; 68:203-12. [PMID: 26320630 DOI: 10.1016/j.molimm.2015.08.008] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 08/06/2015] [Accepted: 08/10/2015] [Indexed: 11/19/2022]
Abstract
Bacterial lipopolysaccharide (LPS) activates the innate immune system by forming a complex with myeloid differentiation factor 2 (MD-2) and Toll-like receptor 4 (TLR4), which is present on antigen presenting cells. MD-2 plays an essential role in this activation of the innate immune system as a member of the ternary complex, TLR4:MD-2:LPS. With the goal of further understanding the molecular details of the interaction of MD-2 with LPS and TLR4, and possibly toward engineering dominant negative regulators of the MD-2 protein, here we subjected MD-2 to a mutational analysis using yeast display. The approach included generation of site-directed alanine mutants, and ligand-driven selections of MD-2 mutant libraries. Our findings showed that: (1) proline mutations in the F119-K132 loop that binds LPS were strongly selected for enhanced yeast surface stability, (2) there was a preference for positive-charged side chains (R/K) at residue 120 for LPS binding, and negative-charged side chains (D/E) for TLR4 binding, (3) aromatic residues were strongly preferred at F119 and F121 for LPS binding, and (4) an MD-2 mutant (T84N/D101A/S118A/S120D/K122P) exhibited increased binding to TLR4 but decreased binding to LPS. These studies revealed the impact of specific residues and regions of MD-2 on the binding of LPS and TLR4, and they provide a framework for further directed evolution of the MD-2 protein.
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Affiliation(s)
- Daiva M Mattis
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Adam S Chervin
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA
| | - Diana R Ranoa
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | - Stacy L Kelley
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | - Richard I Tapping
- Department of Microbiology, University of Illinois, Urbana, IL 61801, USA
| | - David M Kranz
- Department of Biochemistry, University of Illinois, Urbana, IL 61801, USA.
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24
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Chebrolu C, Artner D, Sigmund AM, Buer J, Zamyatina A, Kirschning CJ. Species and mediator specific TLR4 antagonism in primary human and murine immune cells by βGlcN(1↔1)αGlc based lipid A mimetics. Mol Immunol 2015; 67:636-41. [PMID: 26319313 DOI: 10.1016/j.molimm.2015.07.037] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2014] [Revised: 06/18/2015] [Accepted: 07/29/2015] [Indexed: 12/25/2022]
Abstract
Immune stimulatory pathogen associated molecular patterns (PAMPs) are major drivers of infection pathology. Infections with Gram-negative bacteria or negatively polar and single stranded RNA influenza virus are prominent causes of morbidity and mortality. Toll-like receptor (TLR) 4 is a major host sensor for both of the two infections. In order to inhibit TLR4 driven immune activation we recently developed synthetic tetra-acylated lipid A mimetics based on a conformationally restricted βGlcN(1↔1)αGlcN disaccharide scaffold (DA-compounds) that antagonized ectopically overexpressed human and murine TLR4/MD-2 complexes. Here we comparatively analyzed human peripheral blood mononuclear cell (hPBMC) and murine bone marrow derived macrophage (mBM) activation upon 30 min of preincubation in vitro with six variably acylated DA-compounds. 16 h subsequent to consequent LPS challenge, we sampled culture supernatants for cytokine and NO concentration analysis. Four compounds significantly inhibited release of both TNF and IL-6 by hPBMCs upon LPS challenge. In contrast, three compounds effectively inhibited mBM production of MIP-2 and KC, and even five of them inhibited IL-6 and NO production. LPS driven like other TLR ligand driven mBM TNF release was largely unimpaired. The inhibitory effect was specific in that Clo75 driven cytokine release by both hPBMCs and mBMs was unimpaired by the compounds analyzed. Our results indicate biological species specificity of LPS antagonism by variably tetraacylated lipid A mimetics and validate three out of six DA-antagonists as promising candidates for development of therapeutically applicable anti-inflammatory compounds.
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Affiliation(s)
- Chiranjeevi Chebrolu
- Institute of Medical Microbiology, University of Duisburg-Essen, 45147 Essen, Germany
| | - Daniel Artner
- Department of Chemistry, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Anna M Sigmund
- Institute of Medical Microbiology, University of Duisburg-Essen, 45147 Essen, Germany
| | - Jan Buer
- Institute of Medical Microbiology, University of Duisburg-Essen, 45147 Essen, Germany
| | - Alla Zamyatina
- Department of Chemistry, University of Natural Resources and Life Sciences, 1190 Vienna, Austria
| | - Carsten J Kirschning
- Institute of Medical Microbiology, University of Duisburg-Essen, 45147 Essen, Germany.
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25
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Scior T, Paiz-Candia B, Islas ÁA, Sánchez-Solano A, Millan-Perez Peña L, Mancilla-Simbro C, Salinas-Stefanon EM. Predicting a double mutant in the twilight zone of low homology modeling for the skeletal muscle voltage-gated sodium channel subunit beta-1 (Nav1.4 β1). Comput Struct Biotechnol J 2015; 13:229-40. [PMID: 25904995 PMCID: PMC4402383 DOI: 10.1016/j.csbj.2015.03.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 03/18/2015] [Accepted: 03/21/2015] [Indexed: 12/18/2022] Open
Abstract
The molecular structure modeling of the β1 subunit of the skeletal muscle voltage-gated sodium channel (Nav1.4) was carried out in the twilight zone of very low homology. Structural significance can per se be confounded with random sequence similarities. Hence, we combined (i) not automated computational modeling of weakly homologous 3D templates, some with interfaces to analogous structures to the pore-bearing Nav1.4 α subunit with (ii) site-directed mutagenesis (SDM), as well as (iii) electrophysiological experiments to study the structure and function of the β1 subunit. Despite the distant phylogenic relationships, we found a 3D-template to identify two adjacent amino acids leading to the long-awaited loss of function (inactivation) of Nav1.4 channels. This mutant type (T109A, N110A, herein called TANA) was expressed and tested on cells of hamster ovary (CHO). The present electrophysiological results showed that the double alanine substitution TANA disrupted channel inactivation as if the β1 subunit would not be in complex with the α subunit. Exhaustive and unbiased sampling of “all β proteins” (Ig-like, Ig) resulted in a plethora of 3D templates which were compared to the target secondary structure prediction. The location of TANA was made possible thanks to another “all β protein” structure in complex with an irreversible bound protein as well as a reversible protein–protein interface (our “Rosetta Stone” effect). This finding coincides with our electrophysiological data (disrupted β1-like voltage dependence) and it is safe to utter that the Nav1.4 α/β1 interface is likely to be of reversible nature.
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Affiliation(s)
- Thomas Scior
- Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, Puebla, Mexico
| | - Bertin Paiz-Candia
- Facultad de Ciencias Químicas, Universidad Autónoma de Puebla, Puebla, Mexico
| | - Ángel A Islas
- Laboratorio de Biofísica, Instituto de Fisiología, Universidad Autónoma de Puebla, Puebla, Mexico
| | - Alfredo Sánchez-Solano
- Laboratorio de Biofísica, Instituto de Fisiología, Universidad Autónoma de Puebla, Puebla, Mexico
| | | | - Claudia Mancilla-Simbro
- Laboratorio de Biofísica, Instituto de Fisiología, Universidad Autónoma de Puebla, Puebla, Mexico
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26
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Garate JA, Stöckl J, Fernández-Alonso MDC, Artner D, Haegman M, Oostenbrink C, Jiménez-Barbero J, Beyaert R, Heine H, Kosma P, Zamyatina A. Anti-endotoxic activity and structural basis for human MD-2·TLR4 antagonism of tetraacylated lipid A mimetics based on βGlcN(1↔1)αGlcN scaffold. Innate Immun 2014; 21:490-503. [PMID: 25394365 PMCID: PMC4452626 DOI: 10.1177/1753425914550426] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2014] [Accepted: 08/11/2014] [Indexed: 01/25/2023] Open
Abstract
Interfering with LPS binding by the co-receptor protein myeloid differentiation factor 2 (MD-2) represents a useful approach for down-regulation of MD-2·TLR4-mediated innate immune signaling, which is implicated in the pathogenesis of a variety of human diseases, including sepsis syndrome. The antagonistic activity of a series of novel synthetic tetraacylated bis-phosphorylated glycolipids based on the βGlcN(1↔1)αGlcN scaffold was assessed in human monocytic macrophage-like cell line THP-1, dendritic cells and human epithelial cells. Two compounds were shown to inhibit efficiently the LPS-induced inflammatory signaling by down-regulation of the expression of TNF-α, IL-6, IL-8, IL-10 and IL-12 to background levels. The binding of the tetraacylated by (R)-3-hydroxy-fatty acids (2 × C12, 2 × C14), 4,4′-bisphosphorylated βGlcN(1↔1)αGlcN-based lipid A mimetic DA193 to human MD-2 was calculated to be 20-fold stronger than that of Escherichia coli lipid A. Potent antagonistic activity was related to a specific molecular shape induced by the β,α(1↔1)-diglucosamine backbone. ‘Co-planar’ relative arrangement of the GlcN rings was inflicted by the double exo-anomeric conformation around both glycosidic torsions in the rigid β,α(1↔1) linkage, which was ascertained using NOESY NMR experiments and confirmed by molecular dynamics simulation. In contrast to the native lipid A ligands, the binding affinity of βGlcN(1↔1)αGlcN-based lipid A mimetics to human MD-2 was independent on the orientation of the diglucosamine backbone of the synthetic antagonist within the binding pocket of hMD-2 (rotation by 180°) allowing for two equally efficient binding modes as shown by molecular dynamics simulation.
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Affiliation(s)
- Jose Antonio Garate
- Institute of Molecular Modelling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Johannes Stöckl
- Institute of Immunology, Medical University of Vienna, Vienna, Austria
| | | | - Daniel Artner
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Mira Haegman
- Department for Biomedical Molecular Biology, Unit of Molecular Signal Transduction in Inflammation, Ghent University, Inflammation Research Center, VIB, Ghent, Belgium
| | - Chris Oostenbrink
- Institute of Molecular Modelling and Simulation, University of Natural Resources and Life Sciences, Vienna, Austria
| | | | - Rudi Beyaert
- Department for Biomedical Molecular Biology, Unit of Molecular Signal Transduction in Inflammation, Ghent University, Inflammation Research Center, VIB, Ghent, Belgium
| | - Holger Heine
- Research Group Innate Immunity, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Airway Research Center North (ARCN), Member of the German Center for Lung Research (DZL), Borstel, Germany
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Alla Zamyatina
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
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27
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Nour A, Hayashi T, Chan M, Yao S, Tawatao RI, Crain B, Tsigelny IF, Kouznetsova VL, Ahmadiiveli A, Messer K, Pu M, Corr M, Carson DA, Cottam HB. Discovery of substituted 4-aminoquinazolines as selective Toll-like receptor 4 ligands. Bioorg Med Chem Lett 2014; 24:4931-8. [PMID: 25288184 DOI: 10.1016/j.bmcl.2014.09.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/10/2014] [Accepted: 09/12/2014] [Indexed: 01/23/2023]
Abstract
The Toll-like receptors (TLRs) are critical components of the innate immune system that regulate immune recognition in part through NF-κB activation. A human cell-based high throughput screen (HTS) revealed substituted 4-aminoquinazolines to be small molecular weight activators of NF-κB. The most potent hit compound predominantly stimulated through the human TLR4/MD2 complex, and had less activity with the mouse TLR4/MD2. There was no activity with other TLRs and the TLR4 activation was MD-2 dependent and CD14 independent. Synthetic modifications of the quinazoline scaffold at the 2 and 4 positions revealed trends in structure-activity relationships with respect to TLR dependent production of the NF-κB associated cytokine IL-8 in human peripheral blood mononuclear cells, as well as IL-6 in mouse antigen presenting cells. Furthermore, the hit compound in this series also activated the interferon signaling pathway resulting in type I interferon production. Substitution at the O-phenyl moiety with groups such as bromine, chlorine and methyl resulted in enhanced immunological activity. Computational studies indicated that the 4-aminoquinazoline compounds bind primarily to human MD-2 in the TLR4/MD-2 complex. These small molecules, which preferentially stimulate human rather than mouse innate immune cells, may be useful as adjuvants or immunotherapeutic agents.
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Affiliation(s)
- Afshin Nour
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Tomoko Hayashi
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Michael Chan
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Shiyin Yao
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Rommel I Tawatao
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Brian Crain
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Igor F Tsigelny
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States; San Diego Supercomputer Center, and University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States; Department of Neurosciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States
| | - Valentina L Kouznetsova
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States; San Diego Supercomputer Center, and University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, United States
| | - Alast Ahmadiiveli
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Karen Messer
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Minya Pu
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Maripat Corr
- Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0663, United States
| | - Dennis A Carson
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
| | - Howard B Cottam
- Moores Cancer Center, University of California, San Diego, 3855 Health Sciences Drive, La Jolla, CA 92093-0819, United States
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28
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Oblak A, Jerala R. The molecular mechanism of species-specific recognition of lipopolysaccharides by the MD-2/TLR4 receptor complex. Mol Immunol 2015; 63:134-42. [PMID: 25037631 DOI: 10.1016/j.molimm.2014.06.034] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 06/20/2014] [Accepted: 06/25/2014] [Indexed: 01/17/2023]
Abstract
Lipid A, a component of bacterial lipopolysaccharide, is a conserved microbe-associated molecular pattern that activates the MD-2/TLR4 receptor complex. Nevertheless, bacteria produce lipid A molecules of considerable structural diversity. The human MD-2/TLR4 receptor most efficiently recognizes hexaacylated bisphosphorylated lipid A produced by enterobacteria, but in some animal species the immune response can be elicited also by alternative lipid A varieties, such as tetraacylated lipid IVa or pentaacylated lipid A of Rhodobacter spheroides. Several crystal structures revealed that hexaacylated lipid A and tetraacylated lipid IVa activate the murine MD-2/TLR4 in a similar manner, but failed to explain the antagonistic vs. agonistic activity of lipid IVa in the human vs. equine receptor, respectively. Targeted mutagenesis studies of the receptor complex revealed intricate combination of electrostatic and hydrophobic interactions primarily within the MD-2 co-receptor, but with a contribution of TLR4 as well, that contribute to species-specific recognition of lipid A. We will review current knowledge regarding lipid A diversity and species-specific activation of the MD-2/TLR4 receptor complex in different species (e.g. human, mouse or equine) by lipid A varieties.
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29
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Lu Z, Li Y, Samuvel DJ, Jin J, Zhang X, Lopes-Virella MF, Huang Y. MD-2 is involved in the stimulation of matrix metalloproteinase-1 expression by interferon-γ and high glucose in mononuclear cells - a potential role of MD-2 in Toll-like receptor 4-independent signalling. Immunology 2013; 140:301-13. [PMID: 23800176 DOI: 10.1111/imm.12138] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2013] [Revised: 05/20/2013] [Accepted: 06/20/2013] [Indexed: 11/27/2022] Open
Abstract
We reported recently that treatment of diabetic apolipoprotein E-deficient mice with the Toll-like receptor 4 (TLR4) antagonist Rs-LPS, a lipopolysaccharide isolated from Rhodobacter sphaeroides, inhibited atherosclerosis. Since it is known that Rs-LPS antagonizes TLR4 by targeting TLR4 co-receptor MD-2, this finding indicates that MD-2 is a potential target for the treatment of atherosclerosis. In this study, we determined if MD-2 is involved in the gene expression regulated by signalling pathways independent of TLR4. Given that interferon-γ (IFNγ) and hyperglycaemia play key roles in atherosclerosis, we determined if MD-2 is involved in IFN-γ and high-glucose-regulated gene expression in mononuclear cells. Results showed that IFN-γ and high glucose synergistically stimulated matrix metalloproteinase 1 (MMP-1), a proteinase essential for vascular tissue remodelling and atherosclerosis, in U937 mononuclear cells, but Rs-LPS inhibited the MMP-1 stimulation. To provide more evidence for a role of MD-2 in IFN-γ-stimulated MMP-1, studies using antibodies and small interfering RNA demonstrated that MD-2 blockade or knockdown attenuated the effect of IFN-γ on MMP-1. Furthermore, studies using PCR arrays showed that MD-2 blockade had a similar effect as IFN-γ receptor blockade on the inhibition of IFN-γ-stimulated pro-inflammatory molecules. Although these findings indicate the involvement of MD-2 in IFN-γ signalling, we also observed that MD-2 was up-regulated by IFN-γ and high glucose. We found that MD-2 up-regulation by IFN-γ played an essential role in the synergistic effect of IFN-γ and LPS on MMP-1 expression. Taken together, these findings indicate that MD-2 is involved in IFN-γ signalling and IFN-γ-augmented MMP-1 up-regulation by LPS.
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Affiliation(s)
- Zhongyang Lu
- Division of Endocrinology, Diabetes and Medical Genetics, Department of Medicine, College of Medicine, Medical University of South Carolina, Charleston, SC, USA
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Mai CW, Kang YB, Pichika MR. Should a Toll-like receptor 4 (TLR-4) agonist or antagonist be designed to treat cancer? TLR-4: its expression and effects in the ten most common cancers. Onco Targets Ther 2013; 6:1573-87. [PMID: 24235843 PMCID: PMC3821792 DOI: 10.2147/ott.s50838] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Toll-like receptor 4 (TLR-4) is well known for its host innate immunity. Despite the fact that TLR-4 activation confers antitumor responses; emerging evidence suggests that TLR-4 is associated with tumor development and progression. It is now clear that overactivation of TLR-4, through various immune mediators, may cause immune response dysfunction, resulting in tumorigenesis. Different cancers could have different extents of TLR-4 involvement during tumorigenesis or tumor progression. In this review, we focus on infection- and inflammation-related TLR-4 activation in noncancer and cancer cells, as well as on the current evidence about the role of TLR-4 in ten of the most common cancers, viz, head and neck cancer, lung cancer, gastrointestinal cancer, liver cancer, pancreatic cancer, skin cancer, breast cancer, ovarian cancer, cervical cancer, and prostate cancer.
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Affiliation(s)
- Chun Wai Mai
- Department of Pharmaceutical Chemistry, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| | - Yew Beng Kang
- Department of Pharmaceutical Chemistry, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
| | - Mallikarjuna Rao Pichika
- Department of Pharmaceutical Chemistry, School of Pharmacy, International Medical University, Kuala Lumpur, Malaysia
- Correspondence: Mallikarjuna Rao Pichika, Department of Pharmaceutical Chemistry, School of Pharmacy, International Medical University, 126, Jalan Jalil Perkasa 19, Bukit Jalil, 57000, Kuala Lumpur, Malaysia, Tel +60 32 731 7208, Fax +60 38 656 7229, Email
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Keestra AM, de Zoete MR, Bouwman LI, Vaezirad MM, van Putten JPM. Unique features of chicken Toll-like receptors. Dev Comp Immunol 2013; 41:316-323. [PMID: 23628643 DOI: 10.1016/j.dci.2013.04.009] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2013] [Accepted: 04/16/2013] [Indexed: 06/02/2023]
Abstract
Toll-like receptors (TLRs) are a major class of innate immune pattern recognition receptors that have a key role in immune homeostasis and the defense against infections. The research explosion that followed the discovery of TLRs more than a decade ago has boosted fundamental knowledge on the function of the immune system and the resistance against disease, providing a rational for clinical modulation of the immune response. In addition, the conserved nature of the ancient TLR system throughout the animal kingdom has enabled a comparative biology approach to understand the evolution, structural architecture, and function of TLRs. In the present review we focus on TLR biology in the avian species, and, especially, on the unique functional properties of the chicken TLR repertoire.
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Affiliation(s)
- A Marijke Keestra
- Department of Infectious Disease & Immunology, Utrecht University, The Netherlands
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Švajger U, Brus B, Turk S, Sova M, Hodnik V, Anderluh G, Gobec S. Novel toll-like receptor 4 (TLR4) antagonists identified by structure- and ligand-based virtual screening. Eur J Med Chem 2013; 70:393-9. [PMID: 24177366 DOI: 10.1016/j.ejmech.2013.10.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/01/2013] [Accepted: 10/07/2013] [Indexed: 11/24/2022]
Abstract
Toll-like receptor 4 (TLR4) in complex with its accessory protein MD-2 represents an emerging target for the treatment of severe sepsis and neuropathic pain. We performed structure-based and ligand-based virtual screening targeting the TLR4-MD-2 interface. Three in silico hit compounds showed promising TLR4 antagonistic activities with micromolar IC50 values. These compounds also suppressed cytokine secretion by human peripheral blood mononuclear cells. The specific affinity of the most potent hit was confirmed by surface plasmon resonance direct-binding experiments. The results of our study represent a very promising starting point for the development of potent small-molecule antagonists of TLR4.
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Tsukamoto H, Ihara H, Ito R, Ukai I, Suzuki N, Kimoto M, Tomioka Y, Ikeda Y. MD-2-dependent human Toll-like receptor 4 monoclonal antibodies detect extracellular association of Toll-like receptor 4 with extrinsic soluble MD-2 on the cell surface. Biochem Biophys Res Commun 2013; 440:31-6. [PMID: 24021278 DOI: 10.1016/j.bbrc.2013.09.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2013] [Accepted: 09/02/2013] [Indexed: 11/18/2022]
Abstract
MD-2 is essential for lipopolysaccharide (LPS) recognition of Toll-like receptor 4 (TLR4) but not for cell surface expression. The TLR4/MD-2 complex is formed intracellularly through co-expression. Extracellular complex formation remains a matter for debate because of the aggregative nature of secreted MD-2 in the absence of TLR4 co-expression. We demonstrated extracellular complex formation using three independent monoclonal antibodies (mAbs), all of which are specific for complexed TLR4 but unreactive with free TLR4 and MD-2. These mAbs bound to TLR4-expressing Ba/F3 cells only when co-cultured with MD-2-secreting Chinese hamster ovary cells or incubated with conditioned medium from these cells. All three mAbs bound the extracellularly formed complex indistinguishably from the intracellularly formed complex in titration studies. In addition, we demonstrated that two mAbs lost their affinity for TLR4/MD-2 on LPS stimulation, suggesting that these mAbs bound to conformation-sensitive epitopes. This was also found when the extracellularly formed complex was stimulated with LPS. Additionally, we showed that cell surface TLR4 and extrinsically secreted MD-2 are capable of forming the functional complex extracellularly, indicating an additional or alternative pathway for the complex formation.
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Affiliation(s)
- Hiroki Tsukamoto
- Laboratory of Oncology, Pharmacy Practice and Sciences, Graduate School of Pharmaceutical Sciences, Tohoku University, 6-3 Aoba, Aramaki, Sendai 980-8578, Japan; Division of Molecular Cell Biology, Department of Biomolecular Sciences, Saga University Faculty of Medicine, 5-1-1 Nabeshima, Saga 849-8501, Japan.
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Scior T, Lozano-Aponte J, Figueroa-Vazquez V, Yunes-Rojas JA, Zähringer U, Alexander C. Three-dimensional mapping of differential amino acids of human, murine, canine and equine TLR4/ MD-2 receptor complexes conferring endotoxic activation by lipid A, antagonism by Eritoran and species-dependent activities of Lipid IVA in the mammalian LPS sensor system. Comput Struct Biotechnol J 2013; 7:e201305003. [PMID: 24688739 PMCID: PMC3962092 DOI: 10.5936/csbj.201305003] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2012] [Revised: 07/21/2013] [Accepted: 07/21/2013] [Indexed: 11/23/2022] Open
Abstract
A literature review concerning the unexpected species differences of the vertebrate innate immune response to lipid IVA was published in CSBJ prior to the present computational study to address the unpaired activity-sequence correlation of prototypic E. coli -type lipid A and its precursor lipid IVA regarding human, murine, equine and canine species. To this end, their sequences and structures of hitherto known Toll-like receptor 4 (TLR4) and myeloid differentiation factor 2 (MD-2) complexes were aligned and their differential side chain patterns studied. If required due to the lack of the corresponding X-ray crystallographic data, three-dimensional models of TLR4/MD-2/ligand complexes were generated using mono and dimeric crystal structures as templates and in silico docking of the prototypic ligands lipid A, lipid IVA and Eritoran. All differential amino acids were mapped to pinpoint species dependency on an atomic scale, i.e. the possible concert of mechanistically relevant side chains. In its most abstract and general form the three-dimensional (3D-) models devise a triangular interface or “wedge” where molecular interactions between TLR4, MD-2 and ligand itself take place. This study identifies two areas in the wedge related to either agonism or antagonism reflecting why ligands like lipid IVA can possess a species dependent dual activity. Lipid IVA represents an imperfect (underacylated and backbone-flipped), low affinity ligand of mammalian TLR4/MD-2 complexes. Its specific but weak antagonistic activity in the human system is in particular due to the loss of phosphate attraction in the wedge-shaped region conferred by nonhomologous residue changes when compared to crystal and modeled structures of the corresponding murine and equine TLR4/MD-2 complexes. The counter-TLR4/MD-2 unit was also taken into account since agonist-mediated dimerization in a defined m-shaped complex composed of two TLR4/MD-2/agonist subunits triggers intracellular signaling during the innate immune response to bacterial endotoxin exposure.
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Affiliation(s)
- Thomas Scior
- Departamento de Farmacia, Benemérita Universidad Autónoma de Puebla, C.P. 72570 Puebla, Pue., Mexico
| | - Jorge Lozano-Aponte
- Departamento de Farmacia, Benemérita Universidad Autónoma de Puebla, C.P. 72570 Puebla, Pue., Mexico
| | - Vianihuini Figueroa-Vazquez
- Department of Hematology and Laboratory for Cellular Therapy, Instituto Maimonides Investigación Biomédica, Cordoba, Spain
| | | | - Ulrich Zähringer
- Division of Immunochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
| | - Christian Alexander
- Division of Immunochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
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Scior T, Alexander C, Zaehringer U. Reviewing and identifying amino acids of human, murine, canine and equine TLR4 / MD-2 receptor complexes conferring endotoxic innate immunity activation by LPS/lipid A, or antagonistic effects by Eritoran, in contrast to species-dependent modulation by lipid IVa. Comput Struct Biotechnol J 2013; 5:e201302012. [PMID: 24688705 PMCID: PMC3962135 DOI: 10.5936/csbj.201302012] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2012] [Revised: 02/12/2013] [Accepted: 02/17/2013] [Indexed: 11/28/2022] Open
Abstract
There is literature evidence gathered throughout the last two decades reflecting unexpected species differences concerning the immune response to lipid IVa which provides the opportunity to gain more detailed insight by the molecular modeling approach described in this study. Lipid IVa is a tetra-acylated precursor of lipid A in the biosynthesis of lipopolysaccharide (LPS) in Gram-negative bacteria. Lipid A of the prototypic E. coli-type is a hexa-acylated structure that acts as an agonist in all tested mammalian species by innate immunorecognition via the Toll-like receptor 4 (TLR4)/myeloid differentiation factor 2 (MD-2) receptor complex. In contrast, lipid IVa is proinflammatory in mouse cells (agonism) but it remains inactive to human macrophages and even antagonizes the action of potent agonists like E. coli-type lipid A. This particular ambivalent activity profile of lipid IVa has been confirmed in other mammalian species: in equine cells Lipid IVa also acts in a weak agonistic manner, whereas being inactive and antagonizing the lipid A-induced activation of canine TLR4/MD-2. Intriguingly, the respective TLR4 amino acid sequences of the latter species are more identical to the human (67%, 68%) than to the murine (62%, 58%) ortholog. In order to address the unpaired activity-sequence dualism for human, murine, canine and equine species regarding the activity of lipid IVa as compared to LPS and lipid A and, we review the literature and computationally pinpoint the differential biological effects of lipid IVa versus LPS and lipid A to specific amino acid residues. In contrast to lipid IVa the structurally related synthetic compound Eritoran (E5564) acts consistently in an antagonistic manner in these mammalian species and serves as a reference ligand for molecular modeling in this study. The combined evaluation of data sets provided by prior studies and in silico homology mapping of differential residues of TLR4/MD-2 complexes lends detailed insight into the driving forces of the characteristic binding modes of the lipid A domain in LPS and the precursor structure lipid IVa to the receptor complex in individual mammalian species.
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Affiliation(s)
- Thomas Scior
- Departamento de Farmacia, Benemerita Universidad Autonoma de Puebla, C.P. 72570 Puebla, Pue., Mexico
| | - Christian Alexander
- Division of Immunochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
| | - Ulrich Zaehringer
- Division of Immunochemistry, Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Borstel, Germany
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Teghanemt A, Weiss JP, Gioannini TL. Radioiodination of an endotoxin· MD-2 complex generates a novel sensitive, high-affinity ligand for TLR4. Innate Immun 2013; 19:545-60. [PMID: 23439691 DOI: 10.1177/1753425913475688] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A purified complex of metabolically labeled [(3)H]lipooligosaccharide (LOS) and recombinant human myeloid differentiation factor 2 (MD-2), [(3)H]LOS·MD-2, has been used to demonstrate pM affinity binding interactions with soluble TLR4 ectodomain (TLR4ecd). For measurement of the binding parameters of membrane-bound TLR4, we took advantage of the stability of endotoxin·MD-2 and tyrosine(s) present on the surface of MD-2 to radioiodinate LOS·MD-2. Radioiodinated LOS·MD-2 generated a reagent with an estimated 1:1 molar ratio of [(125)I] to sMD-2 with 20-fold higher specific radioactivity and TLR4-activating properties comparable to metabolically-labeled LOS·MD-2. LOS·MD-2[(125)I] and [(3)H]LOS·MD-2 have similar affinities for soluble (FLAG) TLR4ecd and for membrane-bound TLR4 in HEK293T/TLR4 cells. In a similar dose-dependent manner, sMD-2 and LOS·MD-2 inhibit LOS·MD-2[(125)I] binding to TLR4 indicating the pM affinity binding of LOS·MD-2[(125)I] is agonist-independent. LOS·MD-2[(125)I] allowed measurement of low levels of cell-surface human or murine TLR4 expressed by stable cell lines (2000-3000 sites/cell) and quantitatively measures low levels of 'MD-2-free' TLR4 (est. 250 molecules/cell) in cells co-expressing TLR4 and MD-2. Occupation of 50-100 TLR4/cell by LOS·MD-2 is sufficient to trigger measurable TLR4-dependent cell activation. LOS·MD-2[(125)I] provides a powerful reagent to measure quantitatively functional human and murine cell-surface TLR4, including in cells where surface TLR4 is potentially functionally significant but not detectable by other methods.
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Affiliation(s)
- Athmane Teghanemt
- 1Inflammation Program, Department of Internal Medicine, Roy A. and Lucille J. Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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