1
|
Koganti R, Yadavalli T, Shukla D. In vitro protocol for the optimal induction of inflammation in human monocyte cell lines. STAR Protoc 2023; 4:102342. [PMID: 37300827 PMCID: PMC10323148 DOI: 10.1016/j.xpro.2023.102342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 02/21/2023] [Accepted: 05/10/2023] [Indexed: 06/12/2023] Open
Abstract
The study of inflammation is of key interest to biomedical research; however, techniques to induce inflammation in vitro are difficult to implement. Here, we present a protocol that optimizes the induction and measurement of NF-kB-mediated inflammation in vitro using a human macrophage cell line. We describe steps for growing, differentiating, and inducing inflammation in THP-1 cells. We detail the process of staining and grid-based confocal imaging. We also discuss approaches to test anti-inflammatory drug efficacy in inhibiting inflammatory milieu. For complete details on the use and execution of this protocol, please refer to Koganti et al. (2022).1.
Collapse
Affiliation(s)
- Raghuram Koganti
- Department of Ophthalmology and Visual Sciences, University of Illinois Medical Center, Chicago, IL 60612, USA; Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL 60612, USA
| | - Tejabhiram Yadavalli
- Department of Ophthalmology and Visual Sciences, University of Illinois Medical Center, Chicago, IL 60612, USA
| | - Deepak Shukla
- Department of Ophthalmology and Visual Sciences, University of Illinois Medical Center, Chicago, IL 60612, USA; Department of Microbiology and Immunology, University of Illinois at Chicago, Chicago, IL 60612, USA.
| |
Collapse
|
2
|
More than Antibiotics: Latest Therapeutics in the Treatment and Prevention of Ocular Surface Infections. J Clin Med 2022; 11:jcm11144195. [PMID: 35887958 PMCID: PMC9323953 DOI: 10.3390/jcm11144195] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/18/2022] [Accepted: 07/18/2022] [Indexed: 12/10/2022] Open
Abstract
Ocular surface infections have been common issues for ophthalmologists for decades. Traditional strategies for infection include antibiotics, antiviral agents, and steroids. However, multiple drug-resistant bacteria have become more common with the prevalence of antibiotic use. Furthermore, an ideal treatment for an infectious disease should not only emphasize eliminating the microorganism but also maintaining clear and satisfying visual acuity. Immunogenetic inflammation, tissue fibrosis, and corneal scarring pose serious threats to vision, and they are not attenuated or prevented by traditional antimicrobial therapeutics. Herein, we collected information about current management techniques including stem-cell therapy, probiotics, and gene therapy as well as preventive strategies related to Toll-like receptors. Finally, we will introduce the latest research findings in ocular drug-delivery systems, which may enhance the bioavailability and efficiency of ocular therapeutics. The clinical application of improved delivery systems and novel therapeutics may support people suffering from ocular surface infections.
Collapse
|
3
|
Gasparrini M, Mazzola F, Cuccioloni M, Sorci L, Audrito V, Zamporlini F, Fortunato C, Amici A, Cianci M, Deaglio S, Angeletti M, Raffaelli N. Molecular Insights Into The Interaction Between Human Nicotinamide Phosphoribosyltransferase and Toll-Like Receptor 4. J Biol Chem 2022; 298:101669. [PMID: 35120922 PMCID: PMC8892085 DOI: 10.1016/j.jbc.2022.101669] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Revised: 01/23/2022] [Accepted: 01/25/2022] [Indexed: 12/19/2022] Open
Abstract
The secreted form of the enzyme nicotinamide phosphoribosyltransferase (NAMPT), which catalyzes a key reaction in intracellular NAD biosynthesis, acts as a damage-associated molecular pattern triggering Toll-like receptor 4 (TLR4)-mediated inflammatory responses. However, the precise mechanism of interaction is unclear. Using an integrated approach combining bioinformatics and functional and structural analyses, we investigated the interaction between NAMPT and TLR4 at the molecular level. Starting from previous evidence that the bacterial ortholog of NAMPT cannot elicit the inflammatory response, despite a high degree of structural conservation, two positively charged areas unique to the human enzyme (the α1-α2 and β1-β2 loops) were identified as likely candidates for TLR4 binding. However, alanine substitution of the positively charged residues within these loops did not affect either the oligomeric state or the catalytic efficiency of the enzyme. The kinetics of the binding of wildtype and mutated NAMPT to biosensor-tethered TLR4 was analyzed. We found that mutations in the α1-α2 loop strongly decreased the association rate, increasing the KD value from 18 nM, as determined for the wildtype, to 1.3 μM. In addition, mutations in the β1-β2 loop or its deletion increased the dissociation rate, yielding KD values of 0.63 and 0.22 μM, respectively. Mutations also impaired the ability of NAMPT to trigger the NF-κB inflammatory signaling pathway in human cultured macrophages. Finally, the involvement of the two loops in receptor binding was supported by NAMPT-TLR4 docking simulations. This study paves the way for future development of compounds that selectively target eNAMPT/TLR4 signaling in inflammatory disorders.
Collapse
Affiliation(s)
- Massimiliano Gasparrini
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Francesca Mazzola
- Department of Clinical Sciences, Polytechnic University of Marche, Ancona, Italy
| | | | - Leonardo Sorci
- Department of Materials, Environmental Sciences and Urban Planning, Division of Bioinformatics and Biochemistry, Polytechnic University of Marche, Ancona, Italy
| | | | - Federica Zamporlini
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Carlo Fortunato
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Adolfo Amici
- Department of Clinical Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Michele Cianci
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy
| | - Silvia Deaglio
- Department of Medical Sciences, University of Turin, Turin, Italy
| | - Mauro Angeletti
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Nadia Raffaelli
- Department of Agricultural, Food and Environmental Sciences, Polytechnic University of Marche, Ancona, Italy.
| |
Collapse
|
4
|
Brothers KM, Harvey SAK, Shanks RMQ. Transcription Factor EepR Is Required for Serratia marcescens Host Proinflammatory Response by Corneal Epithelial Cells. Antibiotics (Basel) 2021; 10:antibiotics10070770. [PMID: 34202642 PMCID: PMC8300729 DOI: 10.3390/antibiotics10070770] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/21/2021] [Accepted: 06/22/2021] [Indexed: 11/24/2022] Open
Abstract
Relatively little is known about how the corneal epithelium responds to vision-threatening bacteria from the Enterobacterales order. This study investigates the impact of Serratia marcescens on corneal epithelial cell host responses. We also investigate the role of a bacterial transcription factor EepR, which is a positive regulator of S. marcescens secretion of cytotoxic proteases and a hemolytic surfactant. We treated transcriptomic and metabolomic analysis of human corneal limbal epithelial cells with wild-type bacterial secretomes. Our results show increased expression of proinflammatory and lipid signaling molecules, while this is greatly altered in eepR mutant-treated corneal cells. Together, these data support the model that the S. marcescens transcription factor EepR is a key regulator of host-pathogen interactions, and is necessary to induce proinflammatory chemokines, cytokines, and lipids.
Collapse
|
5
|
Wang L, Zhu J, Zhang Y, Wu J, Guo H, Wu X. Thymic stromal lymphopoietin participates in the TLR2-and TLR4-dependent immune response triggered by Aspergillus fumigatus in human corneal cells. Exp Eye Res 2021; 209:108644. [PMID: 34081998 DOI: 10.1016/j.exer.2021.108644] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Revised: 04/30/2021] [Accepted: 05/24/2021] [Indexed: 12/16/2022]
Abstract
Fungal keratitis constitutes a serious vision-threatening disease. Toll-like receptors (TLRs) comprise key mediators of innate immunity triggered by Aspergillus fumigatus (AF) in the cornea, but the messenger between innate and adaptive immunity remained unknown. Thymic stromal lymphopoietin (TSLP) represents a critical factor of adaptive immunity. Here we investigated the expression of TSLP in corneal epithelial and stromal cells challenged by AF and its relationship with TLRs. We stimulated corneal cells with TLR ligands zymosan or lipopolysaccharide (LPS), human recombinant TSLP, or AF hyphae for various periods, with or without prior TLR2, TLR4, or TSLP inhibition. TLR2, TLR4, TSLP, IL-8, and TNF-α release and expression were measured via enzyme-linked immunosorbent analysis, quantitative polymerase chain reaction, or western blot. Corneal cell stimulation with zymosan or LPS induced up-regulated TSLP expression. Enhanced TSLP expression was associated with AF treatment in human corneal cells; TLR2 or TLR4 inhibition impaired the AF-induced TSLP levels. Human recombinant TSLP augmented TLR2 and TLR4 expression; RNA interference of TSLP attenuated TLR, IL-8, and TNF-α expression stimulated by AF hyphae. These findings indicated that TSLP participates in the immune response of corneal cells triggered by AF, which is closely related to TLR function, and the innate immunity mediated by TLRs could be enhanced by TSLP. Innate immunity may therefore transmit inflammatory signals to adaptive immunity through activation of TSLP; in turn, adaptive immunity likely exerts certain regulatory effects on innate immunity via TSLP. That is, TSLP could interact with innate immunity mediated by TLR2 and TLR4 in human corneal cells challenged by AF and thus may serve as a messenger between the innate and adaptive immune responses in AF keratitis.
Collapse
Affiliation(s)
- Leyi Wang
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, 250012, PR China; Key Laboratory of Cardiovascular Remodeling and Function Research, Shandong University, Jinan, 250012, PR China.
| | - Jing Zhu
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, 250012, PR China; Key Laboratory of Cardiovascular Remodeling and Function Research, Shandong University, Jinan, 250012, PR China.
| | - Yuting Zhang
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, 250012, PR China; Key Laboratory of Cardiovascular Remodeling and Function Research, Shandong University, Jinan, 250012, PR China.
| | - Jiayin Wu
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, 250012, PR China; Key Laboratory of Cardiovascular Remodeling and Function Research, Shandong University, Jinan, 250012, PR China.
| | - Hui Guo
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, 250012, PR China; Key Laboratory of Cardiovascular Remodeling and Function Research, Shandong University, Jinan, 250012, PR China.
| | - Xinyi Wu
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, 250012, PR China.
| |
Collapse
|
6
|
Mousa HM, Saban DR, Perez VL. The cornea IV immunology, infection, neovascularization, and surgery chapter 1: Corneal immunology. Exp Eye Res 2021; 205:108502. [PMID: 33607075 DOI: 10.1016/j.exer.2021.108502] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2020] [Revised: 02/07/2021] [Accepted: 02/10/2021] [Indexed: 12/27/2022]
Abstract
PURPOSE of Review: This review offers an informed and up-to-date insight on the immune profile of the cornea and the factors that govern the regulation of such a unique immune environment. SUMMARY The cornea is a unique tissue that performs the specialized task of allowing light to penetrate for visual interpretation. To accomplish this, the ocular surface requires a distinct immune environment that is achieved through unique structural, cellular and molecular factors. Not only must the cornea be able to fend off invasive infectious agents but also control the inflammatory response as to avoid collateral, and potentially blinding damage; particularly of post-mitotic cells such as the corneal endothelium. To combat infections, both innate and adaptive arms of the inflammatory immune response are at play in the cornea. Dendritic cells play a critical role in coordinating both these responses in order to fend off infections. On the other side of the spectrum, the ocular surface is also endowed with a variety of anatomic and physiologic components that aid in regulating the immune response to prevent excessive, potentially damaging, inflammation. This attenuation of the immune response is termed immune privilege. The balance between pro and anti-inflammatory reactions is key for preservation of the functional integrity of the cornea. RECENT FINDINGS The understanding of the molecular and cellular factors governing corneal immunology and its response to antigens is a growing field. Dendritic cells in the normal cornea play a crucial role in combating infections and coordinating the inflammatory arms of the immune response, particularly through coordination with T-helper cells. The role of neuropeptides is recently becoming more highlighted with different factors working on both sides of the inflammatory balance.
Collapse
Affiliation(s)
- Hazem M Mousa
- Foster Center for Ocular Immunology at Duke Eye Center, Duke University Medical Center, Durham, NC, USA
| | - Daniel R Saban
- Foster Center for Ocular Immunology at Duke Eye Center, Duke University Medical Center, Durham, NC, USA; Department of Immunology, Duke University School of Medicine, Durham, NC, USA
| | - Victor L Perez
- Foster Center for Ocular Immunology at Duke Eye Center, Duke University Medical Center, Durham, NC, USA.
| |
Collapse
|
7
|
Lema C, Reins RY, Redfern RL. High-Mobility Group Box 1 in Dry Eye Inflammation. Invest Ophthalmol Vis Sci 2019; 59:1741-1750. [PMID: 29610858 PMCID: PMC5886030 DOI: 10.1167/iovs.17-23363] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Purpose To determine high-mobility group box 1 (HMGB1) expression during experimental dry eye (EDE) and dry eye-like culture conditions and elucidate its role in corneal dry eye-related inflammation. Methods EDE was induced in 8- to 12-week-old C57BL/6 mice. Corneal tissue sections and lysates from EDE and untreated mice were evaluated for HMGB1 expression by immunostaining and quantitative real-time PCR (qPCR). For in vitro studies, human corneal epithelial cells (HCEC) were treated with hyperosmolar media, toll-like receptor (TLR) agonists, or proinflammatory cytokines to determine HMGB1 expression. HCEC were also treated with human recombinant HMGB1 (hrHMGB1) alone or in combination with inflammatory stimuli, and TNFα, IL-6, and IL-8 expression evaluated by qPCR and ELISA. Nuclear factor-κB (NF-κB) p65 nuclear translocation was determined by immunostaining. Results EDE mice had higher corneal HMGB1 RNA and protein expression compared to untreated animals. In HCEC, hyperosmolar stress and TNFα treatment stimulated HMGB1 production and secretion into culture supernatants. However, in vitro stimulation with hrHMGB1 did not induce secretion of TNFα, IL-6, or IL-8 or NF-κB p65 nuclear translocation. In addition, the inflammatory response elicited by TLR agonists fibroblast-stimulating lipopeptide-1 and lipopolysaccharide was not enhanced by hrHMGB1 treatment. Conclusions HMGB1 expression was enhanced by dry eye conditions in vivo as well as in vitro, during hyperosmolar stress and cytokine exposure, suggesting an important role for HMGB1 in dry eye disease. However, no direct inflammatory effect was observed with HMGB1 treatment. Therefore, under these conditions, HMGB1 does not contribute directly to dry eye-induced inflammation and its function at the ocular surface needs to be explored further.
Collapse
Affiliation(s)
- Carolina Lema
- The Ocular Surface Institute, University of Houston, College of Optometry, Houston, Texas, United States
| | - Rose Y Reins
- The Ocular Surface Institute, University of Houston, College of Optometry, Houston, Texas, United States
| | - Rachel L Redfern
- The Ocular Surface Institute, University of Houston, College of Optometry, Houston, Texas, United States
| |
Collapse
|
8
|
Foulsham W, Coco G, Amouzegar A, Chauhan SK, Dana R. When Clarity Is Crucial: Regulating Ocular Surface Immunity. Trends Immunol 2018; 39:288-301. [PMID: 29248310 PMCID: PMC5880704 DOI: 10.1016/j.it.2017.11.007] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/28/2017] [Accepted: 11/29/2017] [Indexed: 12/23/2022]
Abstract
The ocular surface is a unique mucosal immune compartment in which anatomical, physiological, and immunological features act in concert to foster a particularly tolerant microenvironment. These mechanisms are vital to the functional competence of the eye, a fact underscored by the devastating toll of excessive inflammation at the cornea - blindness. Recent data have elucidated the contributions of specific anatomical components, immune cells, and soluble immunoregulatory factors in promoting homeostasis at the ocular surface. We highlight research trends at this distinctive mucosal barrier and identify crucial gaps in our current knowledge.
Collapse
Affiliation(s)
- William Foulsham
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA; University College London (UCL) Institute of Ophthalmology, University College London, London, UK
| | - Giulia Coco
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Afsaneh Amouzegar
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA
| | - Sunil K Chauhan
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
| | - Reza Dana
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
9
|
Chan JKL, Yuen D, Too PHM, Sun Y, Willard B, Man D, Tam C. Keratin 6a reorganization for ubiquitin-proteasomal processing is a direct antimicrobial response. J Cell Biol 2017; 217:731-744. [PMID: 29191848 PMCID: PMC5800800 DOI: 10.1083/jcb.201704186] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 10/01/2017] [Accepted: 11/08/2017] [Indexed: 01/09/2023] Open
Abstract
Chan et al. show that epithelial cells respond to bacterial components in the environment by releasing subunits of the keratin 6a (K6a) filament network to the cytosol for degradation by the ubiquitin–proteasome system. This generates antimicrobial peptides from K6a that are important for innate defense of the mucosal surface. Skin and mucosal epithelia deploy antimicrobial peptides (AMPs) to eliminate harmful microbes. We reported that the intermediate filament keratin 6a (K6a) is constitutively processed into antimicrobial fragments in corneal epithelial cells. In this study, we show that K6a network remodeling is a host defense response that directly up-regulates production of keratin-derived AMPs (KAMPs) by the ubiquitin–proteasome system (UPS). Bacterial ligands trigger K6a phosphorylation at S19, S22, S37, and S60, leading to network disassembly. Mutagenic analysis of K6a confirmed that the site-specific phosphorylation augmented its solubility. K6a in the cytosol is ubiquitinated by cullin-RING E3 ligases for subsequent proteasomal processing. Without an appreciable increase in K6a gene expression and proteasome activity, a higher level of cytosolic K6a results in enhanced KAMP production. Although proteasome-mediated proteolysis is known to produce antigenic peptides in adaptive immunity, our findings demonstrate its new role in producing AMPs for innate immune defense. Manipulating K6a phosphorylation or UPS activity may provide opportunities to harness the innate immunity of epithelia against infection.
Collapse
Affiliation(s)
- Jonathan K L Chan
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH.,Department of Ophthalmology, Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, OH
| | - Don Yuen
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Priscilla Hiu-Mei Too
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Yan Sun
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Belinda Willard
- Proteomics Core, Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - David Man
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH
| | - Connie Tam
- Department of Ophthalmic Research, Cole Eye Institute and Lerner Research Institute, Cleveland Clinic, Cleveland, OH .,Department of Ophthalmology, Lerner College of Medicine of Case Western Reserve University, Cleveland Clinic, Cleveland, OH
| |
Collapse
|
10
|
Mohammed I, Said DG, Dua HS. Human antimicrobial peptides in ocular surface defense. Prog Retin Eye Res 2017; 61:1-22. [DOI: 10.1016/j.preteyeres.2017.03.004] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2016] [Revised: 03/22/2017] [Accepted: 03/27/2017] [Indexed: 01/17/2023]
|
11
|
Kolar SS, Baidouri H, McDermott AM. Role of Pattern Recognition Receptors in the Modulation of Antimicrobial Peptide Expression in the Corneal Epithelial Innate Response to F. solani. Invest Ophthalmol Vis Sci 2017; 58:2463-2472. [PMID: 28460048 PMCID: PMC5413214 DOI: 10.1167/iovs.16-20658] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Purpose Fusarium solani (F. solani) keratitis is a potentially sight-threatening fungal infection of the cornea. Antimicrobial peptides (AMPs), such as human β-defensins (hBDs) and cathelicidins, essential components of the immune system, likely have a protective role against F. solani keratitis. We examined the role of pattern recognition receptors (PRRs), Dectin-1, and TLR2 in F. solani–induced modulation of AMP expression in vitro. Methods Human corneal epithelial cells (HCECs) were exposed to heat-inactivated F. solani or pathogen-associated molecular patterns (PAMPs) of F. solani (Zymosan or Zymosan Depleted) for 6, 12, or 24 hours following which AMP mRNA and protein levels were determined. Involvement of TLR2 and Dectin-1 was confirmed by using siRNA knock-down (TLR2 and Dectin-1) or chemical inhibitor BAY 61-3606 (Dectin-1). The functional significance of AMP upregulation was tested using culture supernatant from F. solani or PAMP-treated HCECs against F. solani in the presence of hBD2 or LL37 neutralizing antibody. Results We confirm that HCECs express Dectin-1 and TLR2. HCECs demonstrated upregulation of AMPs hBD2 and cathelicidin LL37 following exposure to heat-inactivated F. solani or PAMPs. TLR2 and Dectin-1 knockdown and BAY 61-3606 treatment decreased AMP mRNA upregulation confirming PRR involvement. The culture supernatant from F. solani or PAMP-treated HCECs showed substantial killing of F. solani and hBD2 or LL37 neutralizing antibody significantly decreased this effect implicating involvement of these AMPs. Conclusions These findings demonstrate that Dectin-1 and TLR2 have an important role in regulating F. solani-induced AMP expression in corneal epithelial cells.
Collapse
Affiliation(s)
- Satya Sree Kolar
- The Ocular Surface Institute, University of Houston, College of Optometry, Houston, Texas, United States
| | - Hasna Baidouri
- The Ocular Surface Institute, University of Houston, College of Optometry, Houston, Texas, United States
| | - Alison M McDermott
- The Ocular Surface Institute, University of Houston, College of Optometry, Houston, Texas, United States
| |
Collapse
|
12
|
Liu D, Cao G, Han L, Ye Y, SiMa Y, Ge W. Flavonoids from Radix Tetrastigmae inhibit TLR4/MD-2 mediated JNK and NF-κB pathway with anti-inflammatory properties. Cytokine 2016; 84:29-36. [DOI: 10.1016/j.cyto.2015.08.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/06/2015] [Accepted: 08/07/2015] [Indexed: 12/12/2022]
|
13
|
Lee JE, Kim YH, Rhee CS, Kim DY. Synergistic Effect of Dermatophagoides farinae and Lipopolysaccharides in Human Middle ear Epithelial Cells. ALLERGY, ASTHMA & IMMUNOLOGY RESEARCH 2016; 8:445-56. [PMID: 27334783 PMCID: PMC4921699 DOI: 10.4168/aair.2016.8.5.445] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Revised: 01/03/2016] [Accepted: 01/06/2016] [Indexed: 01/30/2023]
Abstract
Purpose Although the concept of "one airway, one disease," which includes the middle ear space as part of the united airway is well recognized, the role of allergens in otitis media with effusion (OME) is not clearly understood. We aimed to investigate the effect of the interaction between Dermatophagoides farinae (Der f) and lipopolysaccharide (LPS) on the induction of epithelial inflammatory response in vitro. Methods Primary human middle ear epithelial cells were exposed to Der f, LPS, or both in different sequences, and the magnitude of the immunologic responses was compared. The mRNA expressiona of mucin (MUC) 4, 5AC, 5B, 8, GM-CSF, TNF-α, TLR4, and MD-2 were evaluated using real-time PCR. MUC levels before and after siRNA-mediated knockout of TLR4 and MD-2 were assessed. Lastly, the involved cell signaling pathway was evaluated. Results The expressiona of cytokines, and the MUC 4, 5AC, 5B, and 8 genes were augmented by pretreatment with Der f followed by LPS; however, reverse treatment or combined treatment did not induce the same magnitude of response. Increased MUC expression was decreased by TLR4 knockdown, but not by MD-2 knockdown. The signal intensity of MUC 8 was higher in MD-2 over-expressed cells than in those exposed to LPS only. The translocation of nuclear factor-κB was observed in cells pretreated with Der f followed by LPS. Conclusions When Der f treatment preceded LPS exposure, Der f and LPS acted synergistically in the induction of pro-inflammatory cytokines and the MUC gene, suggesting an important role in the development of OME in patients with concealed allergy airway sensitization.
Collapse
Affiliation(s)
- Ji Eun Lee
- Department of Otorhinolaryngology-Head and Neck Surgery, Chosun University College of Medicine, Gwangju, Korea.,Department of Otorhinolaryngology-Head and Neck Surgery, Graduate school of Medicine, Seoul National University, Seoul, Korea
| | - Yeon Hoo Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Chosun University College of Medicine, Gwangju, Korea
| | - Chae Seo Rhee
- Sensory Organ Research Center, Seoul National University Biomedical Research Institute, Seoul, Korea.,Institute of Allergy and Clinical Immunology, Seoul National University Biomedical Research Institute, Seoul, Korea.,Graduate School of Immunology, Seoul National University, Seoul, Korea.,Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Dong Young Kim
- Department of Otorhinolaryngology-Head and Neck Surgery, Seoul National University College of Medicine, Seoul, Korea.
| |
Collapse
|
14
|
Liu DD, Cao G, Han LK, Ye YL, Zhang Q, Sima YH, Ge WH. Flavonoids from Radix Tetrastigmae improve LPS-induced acute lung injury via the TLR4/MD-2-mediated pathway. Mol Med Rep 2016; 14:1733-41. [DOI: 10.3892/mmr.2016.5412] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2015] [Accepted: 05/27/2016] [Indexed: 11/05/2022] Open
|
15
|
Kaur A, Kumar V, Singh S, Singh J, Upadhyay N, Datta S, Singla S, Kumar V. Toll-like receptor-associated keratitis and strategies for its management. 3 Biotech 2015; 5:611-619. [PMID: 28324534 PMCID: PMC4569616 DOI: 10.1007/s13205-015-0280-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 01/27/2015] [Indexed: 11/16/2022] Open
Abstract
Keratitis is an inflammatory condition, characterized by involvement of corneal tissues. Most recurrent challenge of keratitis is infection. Bacteria, virus, fungus and parasitic organism have potential to cause infection. TLR are an important class of protein which has a major role in innate immune response to combat with pathogens. In last past years, extensive research efforts have provided considerable abundance information regarding the role of TLR in various types of keratitis. This paper focuses to review the recent literature illustrating amoebic, bacterial, fungal and viral keratitis associated with Toll-like receptor molecules and summarize existing thoughts on pathogenesis and treatment besides future probabilities for prevention against TLR-associated keratitis.
Collapse
Affiliation(s)
- Amandeep Kaur
- Department of Biotechnology, Lovely Professional University, Phagwara, 144411, Punjab, India
| | - Vijay Kumar
- Department of Chemistry, Lovely Professional University, Phagwara, 144411, Punjab, India
| | - Simranjeet Singh
- Department of Biotechnology, Lovely Professional University, Phagwara, 144411, Punjab, India
| | - Joginder Singh
- Department of Chemistry, Lovely Professional University, Phagwara, 144411, Punjab, India
| | - Niraj Upadhyay
- Department of Chemistry, Lovely Professional University, Phagwara, 144411, Punjab, India.
| | - Shivika Datta
- Department of Zoology, Lovely Professional University, Phagwara, 144411, Punjab, India
| | - Sourav Singla
- Department of Biotechnology, Lovely Professional University, Phagwara, 144411, Punjab, India
| | - Virender Kumar
- Department of Chemistry, Lovely Professional University, Phagwara, 144411, Punjab, India
| |
Collapse
|
16
|
Koyama D, Maruoka S, Gon Y, Shintani Y, Sekiyama T, Hiranuma H, Shikano S, Kuroda K, Takeshita I, Tsuboi E, Soda K, Hashimoto S. Myeloid differentiation-2 is a potential biomarker for the amplification process of allergic airway sensitization in mice. Allergol Int 2015; 64 Suppl:S37-45. [PMID: 26344079 DOI: 10.1016/j.alit.2015.05.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2015] [Revised: 05/04/2015] [Accepted: 05/14/2015] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Allergic sensitization is a key step in the pathogenesis of asthma. However, little is known about the molecules that are critical regulators for establishing allergic sensitization of the airway. Thus, we conducted global gene expression profiling to identify candidate genes and signaling pathways involved in house dust mite (HDM)-induced allergic sensitization in the murine airway. METHODS We sensitized and challenged mice with HDM or saline as a control through the airway on days 1 and 8. We evaluated eosinophilia in bronchoalveolar lavage fluid (BALF), airway inflammation, and mucus production on days 7 and 14. We extracted total RNA from lung tissues of HDM- and saline-sensitized mice on days 7 and 14. Microarray analyses were performed to identify up-regulated genes in the lungs of HDM-sensitized mice compared to the control mice. Data analyses were performed using GeneSpring software and gene networks were generated using Ingenuity Pathways Analysis (IPA). RESULTS We identified 50 HDM-mediated, stepwise up-regulated genes in response to allergic sensitization and amplification of allergic airway inflammation. The highest expressed gene was myeloid differentiation-2 (MD-2), a lipopolysaccharide (LPS)-binding component of Toll-like receptor (TLR) 4 signaling complex. MD-2 protein was expressed in lung vascular endothelial cells and was increased in the serum of HDM-sensitized mice, but not in the control mice. CONCLUSIONS Our data suggest MD-2 is a critical regulator of the establishment of allergic airway sensitization to HDM in mice. Serum MD-2 may represent a potential biomarker for the amplification of allergic sensitization and allergic inflammation.
Collapse
Affiliation(s)
- Daisuke Koyama
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Shuichiro Maruoka
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Yasuhiro Gon
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
| | - Yoshitaka Shintani
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Tadataka Sekiyama
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Hisato Hiranuma
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Sotaro Shikano
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Kazumichi Kuroda
- Division of Microbiology, Department of Pathology and Microbiology, Nihon University School of Medicine, Tokyo, Japan
| | - Ikuko Takeshita
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Eriko Tsuboi
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Kaori Soda
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Shu Hashimoto
- Division of Respiratory Medicine, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| |
Collapse
|
17
|
Lee JE, Sun Y, Gjorstrup P, Pearlman E. Inhibition of Corneal Inflammation by the Resolvin E1. Invest Ophthalmol Vis Sci 2015; 56:2728-36. [PMID: 25758817 DOI: 10.1167/iovs.14-15982] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
PURPOSE To investigate the role of the lipid mediator, resolvin E1 (RvE1), in corneal inflammation. METHODS The effect of RvE1 on stimulated human corneal epithelial cells (HCECs) and neutrophils, and mouse macrophage was assessed. C57BL/6 mouse corneas were abraded and treated with RvE1 either before or after stimulation with lipopolysaccharide (LPS) and antibiotic-killed Pseudomonas aeruginosa and Staphylococcus aureus. The levels of CXC chemokines in the cornea were quantified, and the presence of neutrophils in corneal infiltrates was detected by immunohistochemistry and by in vivo confocal microscopy. The effect of RvE1 on apoptosis in the corneal epithelium was assessed using the TUNEL assay. RESULTS RvE1 significantly inhibited cytokine production in HCECs and neutrophils, and mouse macrophages and cornea. The development of corneal infiltrates, specifically neutrophils, in response to stimulation with LPS, P. aeruginosa, and S. aureus was also significantly reduced. There was no apoptotic effect of RvE1 on mouse corneal epithelial cells. CONCLUSIONS RvE1 inhibits corneal inflammation induced by LPS, Gram negative (P. aeruginosa) and Gram positive (S. aureus) bacteria. These findings indicate that RvE1 as a potential anti-inflammatory therapy for patients with corneal inflammation and also, when given together with antibiotics, for bacterial keratitis.
Collapse
Affiliation(s)
- Ji-Eun Lee
- Department of Ophthalmology and Visual Sciences Case Western Reserve University, Cleveland, Ohio, United States
| | - Yan Sun
- Department of Ophthalmology, School of Medicine, Pusan National University, Pusan, Korea
| | - Per Gjorstrup
- Research Institute for Convergence of Biomedical Science and Technology, Pusan National University Yangsan Hospital, Yangsan, Korea
| | - Eric Pearlman
- Resolvyx Pharmaceuticals, Inc., Bedford, Massachusetts, United States
| |
Collapse
|
18
|
The use of an IL-1 receptor antagonist peptide to control inflammation in the treatment of corneal limbal epithelial stem cell deficiency. BIOMED RESEARCH INTERNATIONAL 2015; 2015:516318. [PMID: 25705668 PMCID: PMC4330955 DOI: 10.1155/2015/516318] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Revised: 11/02/2014] [Accepted: 11/03/2014] [Indexed: 11/23/2022]
Abstract
Corneal limbal stem cell deficiency (LSCD) may be treated using ex vivo limbal epithelial stem cells (LESCs) derived from cadaveric donor tissue. However, continuing challenges exist around tissue availability, inflammation, and transplant rejection. Lipopolysaccharide (LPS) or recombinant human IL-1β stimulated primary human keratocyte and LESC models were used to investigate the anti-inflammatory properties of a short chain, IL-1 receptor antagonist peptide for use in LESC sheet growth to control inflammation. The peptide was characterized using mass spectroscopy and high performance liquid chromatography. Peptide cytotoxicity, patterns of cell cytokine expression in response to LPS or IL-1β stimulation, and peptide suppression of this response were investigated by MTS/LDH assays, ELISA, and q-PCR. Cell differences in LPS stimulated toll-like receptor 4 expression were investigated using immunocytochemistry. A significant reduction in rIL-1β stimulated inflammatory cytokine production occurred following LESC and keratocyte incubation with anti-inflammatory peptide and in LPS stimulated IL-6 and IL-8 production following keratocyte incubation with peptide (1 mg/mL) (P < 0.05). LESCs produced no cytokine response to LPS stimulation and showed no TLR4 expression. The peptide supported LESC growth when adhered to a silicone hydrogel contact lens indicating potential use in improved LESC grafting through suppression of inflammation.
Collapse
|
19
|
Zhang D, Mi M, Jiang F, Sun Y, Li Y, Yang L, Fan L, Li Q, Meng J, Yue Z, Liu L, Mei Q. Apple polysaccharide reduces NF-Kb mediated colitis-associated colon carcinogenesis. Nutr Cancer 2014; 67:177-90. [PMID: 25412264 DOI: 10.1080/01635581.2015.965336] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Nuclear factor-kappa B (NF-κB) is an important molecule in mediating inflammatory colitis, which can lead to colorectal cancer (CRC). The aim of this study was to evaluate the chemopreventive efficacy of apple polysaccharide extract (AP) in inhibiting NF-κB-mediated inflammation pathways in CRC. We evaluated AP in vitro in HT-29 and SW620 human CRC cells. We also used the azoxymethane and dextran sodium sulphate (AOM/DSS) model to induce colon carcinogenesis in vivo. The chemoprotective effects of AP were assessed using Western blot, immunofluorescence assay, real-time PCR, electrophoretic mobility shift assay, and flow cytometry. AP reduced AOM/DSS-associated toxicities, prevented carcinogenesis, and decreased the expression of TLR4, MD2, MyD88, TRAM, TRIF-related adapter molecule, interferon-β, tumor necrosis factor-α, and interleukin-6. The protective effects of AP may be related to the inhibition of TLR4/MD2-mediated signaling, including MyD88 and TRIF, as well as the inhibition of NF-κB-mediated inflammatory signaling pathways. Therefore, AP could be used in combination therapy for the prevention of colitis-associated colon cancer.
Collapse
Affiliation(s)
- Dian Zhang
- a Department of Pathogen Biology and Immunology , Xi'an Medical University , Xi'an , China and Key Laboratory of Gastrointestinal Pharmacology of Chinese Materia Medica of the State Administration of Traditional Chinese Medicine, Department of Pharmacology, School of Pharmacy , Fourth Military Medical University , Xi'an , China
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Eslani M, Movahedan A, Afsharkhamseh N, Sroussi H, Djalilian AR. The role of toll-like receptor 4 in corneal epithelial wound healing. Invest Ophthalmol Vis Sci 2014; 55:6108-15. [PMID: 25183764 DOI: 10.1167/iovs.14-14736] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
PURPOSE We evaluated the role of Toll-like receptor 4 (TLR4) in corneal epithelial wound healing. METHODS The expression of TLR4 during in vivo corneal epithelial wound healing was examined by immunostaining in mice. The expression and activation of TLR4 was studied in primary or telomerase-immortalized human corneal epithelial cells (HCEC). Scratch assay was performed to evaluate in vitro wound closure using live time-lapse microscopy. Transwell migration assay and Ki67 immunostaining were done to evaluate migration and proliferation, respectively. Lipopolysaccharide (LPS) was used to activate TLR4, whereas CLI-095 was used for its inhibition. The expression of inflammatory cytokines was determined by RT-PCR and ELISA. The activation of p42/44 and p38 was determined by immunoblotting. RESULTS In the murine model, TLR4 immunostaining was noted prominently in the epithelium 8 hours after wounding. There was a 4-fold increase in the expression of TLR4 6 hours after in vitro scratch wounding (P < 0.001). Confocal microscopy confirmed the membrane localization of TLR4/MD2 complex. There was a significant increase in migration, proliferation, and wound closure in HCEC treated with LPS (P < 0.05), while there was significant decrease with TLR4 inhibition (P < 0.05). Addition of LPS to wounded HCEC resulted in a significant increase in the expression of IL-6, TNF-α, CXCL8/IL8, and CCL5/RANTES at the mRNA and protein levels. Likewise, LPS increased the activation of p42/44 and p38 in wounded HCEC. CONCLUSIONS These results suggest that epithelial wounding induces the expression of functional TLR4. Toll-like receptor 4 signaling appears to contribute to early corneal epithelial wound repair by enhancing migration and proliferation.
Collapse
Affiliation(s)
- Medi Eslani
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Asadolah Movahedan
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Neda Afsharkhamseh
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Herve Sroussi
- Oral Medicine and Diagnostic Sciences, College of Dentistry, University of Illinois at Chicago, Chicago, Illinois, United States
| | - Ali R Djalilian
- Department of Ophthalmology and Visual Sciences, University of Illinois at Chicago, Chicago, Illinois, United States
| |
Collapse
|
21
|
McClure R, Massari P. TLR-Dependent Human Mucosal Epithelial Cell Responses to Microbial Pathogens. Front Immunol 2014; 5:386. [PMID: 25161655 PMCID: PMC4129373 DOI: 10.3389/fimmu.2014.00386] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2014] [Accepted: 07/29/2014] [Indexed: 12/17/2022] Open
Abstract
Toll-like receptor (TLR) signaling represents one of the best studied pathways to implement defense mechanisms against invading microbes in human being as well as in animals. TLRs respond to specific microbial ligands and to danger signals produced by the host during infection, and initiate downstream cascades that activate both innate and adaptive immunity. TLRs are expressed by professional immune cells and by the large majority of non-hematopoietic cells, including epithelial cells. In epithelial tissues, TLR functions are particularly important because these sites are constantly exposed to microorganisms, due to their location at the host interface with the environment. While at these sites specific defense mechanisms and inflammatory responses are initiated via TLR signaling against pathogens, suppression or lack of TLR activation is also observed in response to the commensal microbiota. The mechanisms by which TLR signaling is regulated in mucosal epithelial cells include differential expression and levels of TLRs (and their signaling partners), their cellular localization and positioning within the tissue in a fashion that favors responses to pathogens while dampening responses to commensals and maintaining tissue homeostasis in physiologic conditions. In this review, the expression and activation of TLRs in mucosal epithelial cells of several sites of the human body are examined. Specifically, the oral cavity, the ear canal and eye, the airways, the gut, and the reproductive tract are discussed, along with how site-specific host defense mechanisms are implemented via TLR signaling.
Collapse
Affiliation(s)
- Ryan McClure
- Department of Microbiology, Boston University School of Medicine , Boston, MA , USA
| | - Paola Massari
- Section of Infectious Diseases, Department of Medicine, Boston University School of Medicine , Boston, MA , USA
| |
Collapse
|
22
|
Pandey RK, Yu FS, Kumar A. Targeting toll-like receptor signaling as a novel approach to prevent ocular infectious diseases. Indian J Med Res 2013; 138:609-19. [PMID: 24434316 PMCID: PMC3928694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Toll-like receptors (TLRs) play a key role in the innate immune response to invading pathogens. Thus, their discovery has opened up a wide range of therapeutic possibilities for various infectious and inflammatory diseases. In the last several years, extensive research efforts have provided a considerable wealth of information on the expression and function of TLRs in the eye, with significant implications for better understanding of pathogenesis of infectious eye diseases affecting the cornea, uvea, and the retina. In this review, by using bacterial keratitis and endophthalmitis as examples, we discuss the possibilities of targeting TLR signaling for the prevention or treatment of ocular infectious diseases.
Collapse
Affiliation(s)
- Rajeev K. Pandey
- Department of Ophthalmology, Kresge Eye Institute, Detroit, MI, USA
| | - Fu-shin Yu
- Department of Ophthalmology, Kresge Eye Institute, Detroit, MI, USA,Department of Anatomy & Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Ashok Kumar
- Department of Ophthalmology, Kresge Eye Institute, Detroit, MI, USA,Department of Anatomy & Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA,Reprint requests: Dr Ashok Kumar, Department of Ophthalmology / Kresge Eye Institute, Wayne State University School of Medicine, 4717 St. Antoine, Detroit, MI 48201, USA e-mail:
| |
Collapse
|
23
|
Pearlman E, Sun Y, Roy S, Karmakar M, Hise AG, Szczotka-Flynn L, Ghannoum M, Chinnery HR, McMenamin PG, Rietsch A. Host defense at the ocular surface. Int Rev Immunol 2013; 32:4-18. [PMID: 23360155 DOI: 10.3109/08830185.2012.749400] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Microbial infections of the cornea frequently cause painful, blinding and debilitating disease that is often difficult to treat and may require corneal transplantation. In addition, sterile corneal infiltrates that are associated with contact lens wear cause pain, visual impairment and photophobia. In this article, we review the role of Toll-Like Receptors (TLR) in bacterial keratitis and sterile corneal infiltrates, and describe the role of MD-2 regulation in LPS responsiveness by corneal epithelial cells. We conclude that both live bacteria and bacterial products activate Toll-Like Receptors in the cornea, which leads to chemokine production and neutrophil recruitment to the corneal stroma. While neutrophils are essential for bacterial killing, they also cause tissue damage that results in loss of corneal clarity. These disparate outcomes, therefore, represent a spectrum of disease severity based on this pathway, and further indicate that targeting the TLR pathway is a feasible approach to treating inflammation caused by live bacteria and microbial products. Further, as the P. aeruginosa type III secretion system (T3SS) also plays a critical role in disease pathogenesis by inducing neutrophil apoptosis and facilitating bacterial growth in the cornea, T3SS exotoxins are additional targets for therapy for P. aeruginosa keratitis.
Collapse
Affiliation(s)
- Eric Pearlman
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
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] [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.
Collapse
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
| | | | | |
Collapse
|
25
|
Lee HS, Hattori T, Park EY, Stevenson W, Chauhan SK, Dana R. Expression of toll-like receptor 4 contributes to corneal inflammation in experimental dry eye disease. Invest Ophthalmol Vis Sci 2012; 53:5632-40. [PMID: 22789921 DOI: 10.1167/iovs.12-9547] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Purpose. To investigate the corneal expression of toll-like receptor (TLR) 4 and determine its contribution to the immunopathogenesis of dry eye disease (DED). Methods. Seven to 8-week-old female C57BL/6 mice were housed in a controlled environment chamber and administered scopolamine to induce experimental DED. Mice received intravenous TLR4 inhibitor (Eritoran) to block systemic TLR4-mediated activity. The expression of TLR4 by the corneal epithelium and stroma was evaluated using real-time polymerase chain reaction and flow cytometry. Corneal fluorescein staining (CFS) was performed to evaluate clinical disease severity. The corneal expression of proinflammatory cytokines (IL-1β, IL-6, TNF, and CCL2), corneal infiltration of CD11b(+) antigen-presenting cells, and lymph node frequency of mature MHC-II(hi) CD11b(+) cells were assessed. Results. The epithelial cells of normal corneas expressed TLR4 intracellularly; however, DED significantly increased the cell surface expression of TLR4. Similarly, flow cytometric analysis of stromal cells revealed a significant increase in the expression of TLR4 proteins by DED-induced corneas as compared with normal corneas. DED increased the mRNA expression of TLR4 in corneal stromal cells, but not epithelial cells. TLR4 inhibition decreased the severity of CFS and significantly reduced the mRNA expression of IL-1β, IL-6, and TNF. Furthermore, TLR4 inhibition significantly reduced the corneal infiltration of CD11b(+) cells and the lymph node frequency of MHC-II(hi) CD11b(+) cells. Conclusions. These results suggest that DED increases the corneal expression of TLR4 and that TLR4 participates in the inflammatory response to ocular surface desiccating stress.
Collapse
Affiliation(s)
- Hyun Soo Lee
- Schepens Eye Research Institute, Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, Massachusetts, USA
| | | | | | | | | | | |
Collapse
|
26
|
Ueta M, Kinoshita S. Ocular surface inflammation is regulated by innate immunity. Prog Retin Eye Res 2012; 31:551-75. [PMID: 22728145 DOI: 10.1016/j.preteyeres.2012.05.003] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2012] [Revised: 05/25/2012] [Accepted: 05/28/2012] [Indexed: 01/07/2023]
Abstract
On the ocular surface, as in the intestines and airway, the surface epithelium serves a critical function as the front-line defense of the mucosal innate immune system. Although the detection of microbes is arguably the most important task of the immune system, an exaggerated epithelial host defense reaction to endogenous bacteria may initiate and perpetuate inflammatory mucosal responses. In this review we first describe commensal bacteria found on the ocular surface, which is in contact with the ocular surface epithelium. We also discuss the innate immunity of the ocular surface epithelium and we present the allergic reaction regulated by ocular surface epithelial cells. We address ocular surface inflammation due to disordered innate immunity and we present our hypothesis that the onset of Stevens-Johnson syndrome (SJS) with severe ocular surface complications, a devastating ocular surface inflammatory disease, is strongly associated with abnormality of the innate immune system. In this review we raise the possibility that some ocular surface inflammatory diseases are pathogenetically related with a disordered innate immune response. Focusing on the innate immunity of the ocular surface might help to elucidate the pathogenesis of various ocular surface diseases.
Collapse
Affiliation(s)
- Mayumi Ueta
- Department of Ophthalmology, Kyoto Prefectural University of Medicine, 465 Kajiicho, Hirokoji, Kawaramachi, Kamigyoku, Kyoto 602-0841, Japan.
| | | |
Collapse
|
27
|
Exogenous MD-2 confers lipopolysaccharide responsiveness to human corneal epithelial cells with intracellular expression of TLR4 and CD14. Inflammation 2012; 34:371-8. [PMID: 20700758 DOI: 10.1007/s10753-010-9244-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
In the present study, we aimed to investigate the responsiveness of human corneal epithelial cells (HCECs) to lipopolysaccharide (LPS) in vitro and to elucidate the underlying molecular mechanism(s) controlling the LPS responsiveness. The expression and subcellular localization of toll-like receptor 4 (TLR4) and CD14 and the expression of myeloid differentiation (MD)-2 were studied in SDHCEC1 cells, one HCEC cell line. Upon exposure to different concentrations of LPS, cell responses were evaluated by examining nuclear factor-kappaB (NF-κB) activation and the production of interleukin (IL)-8. The influence of soluble MD-2 on LPS responsiveness were assessed in SDHCEC1 cells pretreated with MD-2-containing conditioned medium before LPS challenge. SDHCEC1 cells expressed both TLR4 and CD14 intracellularly and had no detectable expression of MD-2 transcripts. Unresponsiveness to LPS at doses of up to 1,000 ng/ml was observed in SDHCEC1 cells, which was evidenced by no evident NF-κB activation and IL-8 production. The addition of MD-2 conditioned medium significantly induced NF-κB activation and enhanced the production of IL-8 as compared with the treatment with the control medium (p < 0.05). Meanwhile, the total mRNA amounts of TLR4 and CD14 and the surface expression of the two proteins were significantly (p < 0.05) increased by the pretreatment with MD-2 conditioned medium. LPS hyporesponsiveness of HCECs is largely due to deficient LPS receptor complex formation caused by lack of MD-2 expression. Exogenous MD-2 is capable of restoring the LPS responsiveness, at least partially, through promoting the surface expression of TLR4 and CD14.
Collapse
|
28
|
Ren W, Hu L, Hua F, Jin J, Wang Y, Zhu L. Myeloid differentiation protein 2 silencing decreases LPS-induced cytokine production and TLR4/MyD88 pathway activity in alveolar macrophages. Immunol Lett 2011; 141:94-101. [DOI: 10.1016/j.imlet.2011.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2011] [Revised: 07/07/2011] [Accepted: 07/29/2011] [Indexed: 02/06/2023]
|
29
|
Roy S, Sun Y, Pearlman E. Interferon-gamma-induced MD-2 protein expression and lipopolysaccharide (LPS) responsiveness in corneal epithelial cells is mediated by Janus tyrosine kinase-2 activation and direct binding of STAT1 protein to the MD-2 promoter. J Biol Chem 2011; 286:23753-62. [PMID: 21572044 DOI: 10.1074/jbc.m111.219345] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The inability of epithelial cells from the cornea and other tissues to respond to LPS is reportedly due to low expression of the TLR4 co-receptor MD-2. We generated MD-2(-/-) bone marrow chimeras, and showed that MD-2 expression on non-myeloid cells was sufficient to mediate LPS-induced corneal inflammation. As IFN-γ is produced during Pseudomonas aeruginosa corneal infection, we examined the role of this cytokine on MD-2 expression by primary human corneal epithelial (HCE) cells and HCE cell lines. Exogenous IFN-γ was found to induce MD-2 mRNA, MD-2 cell surface expression, and LPS responsiveness as determined by p65 translocation to the nucleus and production of IL-6, CXCL1, and CXCL8/IL-8. Incubation with either the AG490 JAK2 inhibitor or with STAT1 siRNA blocked STAT1 phosphorylation and MD-2 transcription. Furthermore, EMSA analysis demonstrated that STAT1 binds to the MD-2 promoter, indicating that STAT1 is an MD-2 transcription factor. Together, these findings demonstrate that IFN-γ induces MD-2 expression and LPS responsiveness in HCE cells by JAK-2-dependent STAT1 activation and direct binding to the MD-2 promoter. Furthermore, given our findings on LPS-induced corneal inflammation, it is likely that IFN-γ-induced MD-2 expression by corneal epithelial cells contributes to the host response in vivo, determining the extent of tissue damage and bacterial clearance.
Collapse
Affiliation(s)
- Sanhita Roy
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, Ohio 44095, USA
| | | | | |
Collapse
|
30
|
Abstract
The ocular surface is the first line of defence in the eye against environmental microbes. The ocular innate immune system consists of a combination of anatomical, mechanical and immunological defence mechanisms. TLRs (Toll-like receptors), widely expressed by the ocular surface, are able to recognize microbial pathogens and to trigger the earliest immune response leading to inflammation. Increasing evidence highlights the crucial role of TLRs in regulating innate immune responses during ocular surface infective and non-infective inflammatory conditions. In addition, recent observations have shown that TLRs modulate the adaptive immune response, also playing an important role in ocular autoimmune and allergic diseases. One of the main goals of ocular surface treatment is to control the inflammatory reaction in order to preserve corneal integrity and transparency. Recent experimental evidence has shown that specific modulation of TLR pathways induces an improvement in several ocular inflammatory conditions, such as allergic conjunctivitis, suggesting new therapeutic anti-inflammatory strategies. The purpose of the present review is to summarize the current knowledge of TLRs at the ocular surface and to propose them as potential targets of therapy for ocular inflammatory conditions.
Collapse
|
31
|
Redfern RL, McDermott AM. Toll-like receptors in ocular surface disease. Exp Eye Res 2010; 90:679-87. [PMID: 20346359 DOI: 10.1016/j.exer.2010.03.012] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 03/05/2010] [Accepted: 03/16/2010] [Indexed: 12/12/2022]
Abstract
The ability of the ocular surface to mount an immune response is in part attributed to a family of proteins called toll-like receptors (TLRs). The latter are evolutionary conserved receptors that recognize and respond to various microbes and endogenous ligands. In addition to their recognition function, TLR activation triggers a complex signal transduction cascade that induces the production of inflammatory cytokines and co-stimulatory molecules, thus initiating innate and adaptive immunity. Toll-like receptor expression at the ocular surface is modulated during infection (e.g. Herpes simplex, bacterial keratitis and fungal keratitis) as well as during various inflammatory conditions (allergic conjunctivitis and dry-eye syndrome). Here recent findings regarding TLR expression and their involvement in various ocular surface diseases are discussed.
Collapse
Affiliation(s)
- Rachel L Redfern
- University of Houston, College of Optometry, 505 J. Davis Armistead Building, 4901 Calhoun Rd., Houston, TX 77204-2020, USA.
| | | |
Collapse
|
32
|
Xiaoyan Zhang, Xinyi Wu, Li Gao. Pretreatment with lipopolysaccharide modulates innate immunity in corneal fibroblasts challenged with Aspergillus fumigatus. Innate Immun 2010; 17:237-44. [PMID: 20305039 DOI: 10.1177/1753425910365364] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Aspergillus fumigatus triggers inflammatory responses through Toll-like receptors (TLRs), particularly TLR2 and TLR4. In this study, we tested the hypothesis that lipopolysaccharide (LPS), a ligand of TLR4, can induce tolerance of A. fumigatus hyphae in telomerase-immortalized human stroma fibroblasts (THSFs). The THSFs were pretreated with low-dose LPS for various times and then challenged with A. fumigatus hyphae. We observed that pretreatment of THSFs with low-dose LPS resulted in diminished production of cytokines IL-8 and IL-6 and elevated expression of antimicrobial peptides, such as CC chemokine-ligand 20 (CCL20) and thymosin β4 (Tβ4), upon subsequent A. fumigatus challenge. Furthermore, LPS pretreatment also resulted in suppression of polymorphonuclear leukocyte (PMN) migration. Our results suggested that THSFs pretreated with LPS develop a state of A. fumigatus hyphae tolerance. This may induce protective mechanisms during fungal keratitis to prevent an excessive inflammatory response and to control infection of the cornea.
Collapse
Affiliation(s)
- Xiaoyan Zhang
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong, P.R. China
| | - Xinyi Wu
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong, P.R. China
| | - Li Gao
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong, P.R. China
| |
Collapse
|
33
|
Gao N, Kumar A, Jyot J, Yu FS. Flagellin-induced corneal antimicrobial peptide production and wound repair involve a novel NF-kappaB-independent and EGFR-dependent pathway. PLoS One 2010; 5:e9351. [PMID: 20195469 PMCID: PMC2829077 DOI: 10.1371/journal.pone.0009351] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2009] [Accepted: 01/29/2010] [Indexed: 01/17/2023] Open
Abstract
Background The bacterial protein flagellin plays a major role in stimulating mucosal surface innate immune response to bacterial infection and uniquely induces profound cytoprotection against pathogens, chemicals, and radiation. This study sought to determine signaling pathways responsible for the flagellin-induced inflammatory and cytoprotective effects on human corneal epithelial cells (HCECs). Methodology/Principal Findings Flagellin purified from Pseudomonas aeruginosa (strain PAK) or live bacteria were used to challenge cultured HCECs. The activation of signaling pathways was assessed with Western blot, and the secretion of cytokine/chemokine and production of antimicrobial peptides (AMPs) were measured with ELISA and dot blot, respectively. Effects of flagellin on wound healing were assessed in cultured porcine corneas. L94A (a site mutation in TLR5 binding region) flagellin and PAK expressing L94A flagellin were unable to stimulate NF-κB activation, but were potent in eliciting EGFR signaling in a TGF-α–related pathway in HCECs. Concomitant with the lack of NF-κB activation, L94A flagellin was ineffective in inducing IL-6 and IL-8 production in HCECs. Surprisingly, the secretion of two inducible AMPs, LL-37 and hBD2, was not affected by L94A mutation. Similar to wild-type flagellin, L94A induced epithelial wound closure in cultured porcine cornea through maintaining EGFR-mediated signaling. Conclusions/Significance Our data suggest that inflammatory response mediated by NF-κB can be uncoupled from epithelial innate defense machinery (i.e., AMP expression) and major epithelial proliferation/repair pathways mediated by EGFR, and that flagellin and its derivatives may have broad therapeutic applications in cytoprotection and in controlling infection in the cornea and other mucosal tissues.
Collapse
Affiliation(s)
- Nan Gao
- Departments of Ophthalmology, Anatomy, and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Ashok Kumar
- Departments of Ophthalmology, Anatomy, and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Jeevan Jyot
- Department of Medicine/Infectious Diseases, University of Florida, Gainesville, Florida, United States of America
| | - Fu-Shin Yu
- Departments of Ophthalmology, Anatomy, and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States of America
- * E-mail:
| |
Collapse
|