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Gao N, Yu FS. Lack of Elevated Expression of TGFβ3 Contributes to the Delay of Epithelial Wound Healing in Diabetic Corneas. Invest Ophthalmol Vis Sci 2024; 65:35. [PMID: 38546583 PMCID: PMC10981440 DOI: 10.1167/iovs.65.3.35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/12/2024] [Indexed: 04/01/2024] Open
Abstract
Purpose To investigate the mechanisms underlying the differential roles of TGFβ1 and TGFβ3 in accelerating corneal epithelial wound healing (CEWH) in diabetic (DM) corneas, with normoglycemia (NL) corneas as the control. Methods Two types of diabetic mice, human corneal organ cultures, mouse corneal epithelial progenitor cell lines, and bone marrow-derived macrophages (BMDMs) were employed to assess the effects of TGFβ1 and TGFβ3 on CEWH, utilizing quantitative PCR, western blotting, ELISA, and whole-mount confocal microscopy. Results Epithelial debridement led to an increased expression of TGFβ1 and TGFβ3 in cultured human NL corneas, but only TGFβ1 in DM corneas. TGFβ1 and TGFβ3 inhibition was significantly impeded, but exogenous TGFβ1 and, more potently, TGFβ3 promoted CEWH in cultured TKE2 cells and in NL and DM C57BL6 mouse corneas. Wounding induced similar levels of p-SMAD2/SMAD3 in NL and DM corneas but weaker ERK1/2, Akt, and EGFR phosphorylation in DM corneas compared to NL corneas. Whereas TGFβ1 augmented SMAD2/SMAD3 phosphorylation, TGFβ3 preferentially activated ERK, PI3K, and EGFR in healing DM corneas. Furthermore, TGFβ1 and TGFβ3 differentially regulated the expression of S100a9, PAI-1, uPA/tPA, and CCL3 in healing NL and DM corneas. Finally, TGFβ1 induced the expression of M1 macrophage markers iNOS, CD86, and CTGF, whereas TGFβ3 promoted the expression of M2 markers CD206 and NGF in BMDMs from db/db or db/+ mice. Conclusions Hyperglycemia disrupts the balanced expression of TGFβ3/TGFβ1, resulting in delayed CEWH, including impaired sensory nerve regeneration in the cornea. Supplementing TGFβ3 in DM wounds may hold therapeutic potential for accelerating delayed wound healing in diabetic patients.
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Affiliation(s)
- Nan Gao
- Departments of Ophthalmology and Anatomy and Cell Biology, Kresge Eye Institute, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Fu-Shin Yu
- Departments of Ophthalmology and Anatomy and Cell Biology, Kresge Eye Institute, Wayne State University School of Medicine, Detroit, Michigan, United States
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Wu J, Wang W, Yuan F, Zheng J, Zhang W, Guo H, Wang L, Dai C, Han F, Wu X, Gao J. CXCL16 exacerbates Pseudomonas aeruginosa keratitis by promoting neutrophil activation. Int Immunopharmacol 2024; 127:111375. [PMID: 38154213 DOI: 10.1016/j.intimp.2023.111375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 12/04/2023] [Accepted: 12/11/2023] [Indexed: 12/30/2023]
Abstract
Pseudomonas aeruginosa (PA) keratitis is a major cause of blindness characterized by corneal inflammation. In a murine model of PA keratitis, we assessed the detrimental effects of CXC chemokine ligand 16 (CXCL16). Quantitative PCR (qPCR), western blotting (WB) and immunofluorescence were used to measure the expression and localization of CXCL16 and its receptor, CXC chemokine receptor 6 (CXCR6). Clinical scores, plate counting, and hematoxylin-eosin staining were used to assess infection severity and its exacerbation by CXCL16. Immunofluorescence, myeloperoxidase assays, and flow cytometry were used to detect neutrophil activity and colocalization with CXCR6. WB and immunofluorescence were used to measure levels of reactive oxygen species (ROS) and matrix metalloproteinases (MMPs). These methods also were used to measure the activation of downstream NF-κB signaling and its positive feedback on CXCL16 expression. ELISA, flow cytometry, and qPCR were used to measure the expression of CXCL2 and T helper 17 (Th17) cell-related genes. CXCL16 and CXCR6 expression was increased in infected corneas. Topical application of CXCL16 exacerbated keratitis by increasing corneal bacterial load and promoting neutrophil infiltration, whereas neutralizing antibody against CXCL16 had the opposite effect. CXCL16 also increased ROS and MMP levels. This neutrophil activation may be caused by its positive feedback with the NF-κB pathway and the upregulation of CXCL2 and Th17 cell related-genes. These data suggest that CXCL16 is an attractive therapeutic target for PA keratitis.
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Affiliation(s)
- Jiayin Wu
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China; Department of Ophthalmology, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong 252000, China
| | - Wentao Wang
- Department of Surgery, Liaocheng Tumor Hospital, Liaocheng, Shandong 252000, China
| | - Fengjiao Yuan
- Joint Laboratory for Translational Medicine Research, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong 252000, China
| | - Juan Zheng
- Joint Laboratory for Translational Medicine Research, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong 252000, China
| | - Weihua Zhang
- Department of Ophthalmology, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong 252000, China
| | - Hui Guo
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Leyi Wang
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Chenyang Dai
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Fang Han
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Xinyi Wu
- Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong 250012, China
| | - Jianlu Gao
- Department of Ophthalmology, Liaocheng People's Hospital, Shandong University, Liaocheng, Shandong 252000, China.
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Gao N, Me R, Yu FSX. Diabetes Exacerbates Pseudomonas aeruginosa Keratitis in Streptozotocin-Induced and db/db Mice via Altering Programmed Cell Death Pathways. Invest Ophthalmol Vis Sci 2023; 64:14. [PMID: 37279395 PMCID: PMC10249682 DOI: 10.1167/iovs.64.7.14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/05/2023] [Indexed: 06/08/2023] Open
Abstract
Purpose Patients with diabetes have a higher incidence of infections, which are often more severe. This study aimed to investigate the impact of hyperglycemia on bacterial keratitis caused by Pseudomonas aeruginosa (Pa) in two mouse models of diabetes, streptozotocin-induced type 1 diabetes mellitus (T1DM) and db/db type 2 diabetes mellitus. Methods The susceptibility of corneas to Pa was assessed by determining the inocula required to cause infectious keratitis. Dead or dying cells were identified using TUNEL staining or immunohistochemistry. Specific inhibitors were used to evaluate the role of cell death modulators in Pa keratitis. Cytokines and Treml4 expressions were analyzed using quantitative PCR, and the role of Treml4 in keratitis was determined using small interfering RNA technology. Results DM corneas required significantly fewer inocula to develop Pa keratitis, with T1DM corneas requiring 750 inocula and type 2 diabetes mellitus corneas requiring 2000 inocula, compared with 10,000 inocula required for normal (NL) mice. T1DM corneas had more TUNEL-positive and fewer F4/80-positive cells than NL corneas. Phospho-caspase 8 (apoptosis) and -RIPK3 (necroptosis) staining was more intense in the epithelial and stromal layers of NL and T1DM corneas, respectively. Pa keratitis was augmented by targeting caspase-8 and prevented by RIPK3 inhibition in both NL and T1DM mice. Hyperglycemia suppressed IL-17A/F and augmented IL-17C, IL-1β, IL-1Ra, and TREML4, the downregulation of which protected T1DM corneas from Pa infection by suppressing necroptosis. RIPK3 inhibition blocked Pa infection in db/+ mice and significantly decreased the severity of keratitis in db/db mice. Conclusions Hyperglycemia exacerbates bacterial keratitis in B6 mice by skewing apoptosis toward necroptosis. Preventing or reversing this transition may serve as an adjunct therapy for treating microbial keratitis in patients with diabetes.
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Affiliation(s)
- Nan Gao
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Rao Me
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, United States
| | - Fu-shin X. Yu
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, United States
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Song L, Xiong D, Wen Y, Tan R, Kang X, Jiao X, Pan Z. Transcriptome Sequencing Reveals Salmonella Flagellin Activation of Interferon-β-Related Immune Responses in Macrophages. Curr Issues Mol Biol 2023; 45:2798-2816. [PMID: 37185707 PMCID: PMC10136974 DOI: 10.3390/cimb45040183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/20/2023] [Accepted: 03/22/2023] [Indexed: 03/30/2023] Open
Abstract
The flagellin (FliC) of Salmonella typhimurium is a potential vaccine adjuvant as it can activate innate immunity and promote acquired immune responses. Macrophages are an important component of the innate immune system. The mechanism of flagellin’s adjuvant activity has been shown to be related to its ability to activate macrophages. However, few studies have comprehensively investigated the effects of Salmonella flagellin in macrophages using transcriptome sequencing. In this study, RNA-Seq was used to analyze the expression patterns of RAW264.7 macrophages induced by FliC to identify novel transcriptomic signatures in macrophages. A total of 2204 differentially expressed genes were found in the FliC-treated group compared with the control. Gene ontology and KEGG pathway analyses identified the top significantly regulated functional classification and canonical pathways, which were mainly related to immune responses and regulation. Inflammatory cytokines (IL-6, IL-1β, TNF-α, etc.) and chemokines (CXCL2, CXCL10, CCL2, etc.) were highly expressed in RAW264.7 cells following stimulation. Notably, flagellin significantly increased the expression of interferon (IFN)-β. In addition, previously unidentified IFN regulatory factors (IRFs) and IFN-stimulated genes (ISGs) were also significantly upregulated. The results of RNA-Seq were verified, and furthermore, we demonstrated that flagellin increased the expression of IFN-β and IFN-related genes (IRFs and ISGs) in bone marrow-derived dendritic cells and macrophages. These results suggested that Salmonella flagellin can activate IFN-β-related immune responses in macrophages, which provides new insight into the immune mechanisms of flagellin adjuvant.
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Johnstone KF, Herzberg MC. Antimicrobial peptides: Defending the mucosal epithelial barrier. FRONTIERS IN ORAL HEALTH 2022; 3:958480. [PMID: 35979535 PMCID: PMC9376388 DOI: 10.3389/froh.2022.958480] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Accepted: 06/30/2022] [Indexed: 11/13/2022] Open
Abstract
The recent epidemic caused by aerosolized SARS-CoV-2 virus illustrates the importance and vulnerability of the mucosal epithelial barrier against infection. Antimicrobial proteins and peptides (AMPs) are key to the epithelial barrier, providing immunity against microbes. In primitive life forms, AMPs protect the integument and the gut against pathogenic microbes. AMPs have also evolved in humans and other mammals to enhance newer, complex innate and adaptive immunity to favor the persistence of commensals over pathogenic microbes. The canonical AMPs are helictical peptides that form lethal pores in microbial membranes. In higher life forms, this type of AMP is exemplified by the defensin family of AMPs. In epithelial tissues, defensins, and calprotectin (complex of S100A8 and S100A9) have evolved to work cooperatively. The mechanisms of action differ. Unlike defensins, calprotectin sequesters essential trace metals from microbes, which inhibits growth. This review focuses on defensins and calprotectin as AMPs that appear to work cooperatively to fortify the epithelial barrier against infection. The antimicrobial spectrum is broad with overlap between the two AMPs. In mice, experimental models highlight the contribution of both AMPs to candidiasis as a fungal infection and periodontitis resulting from bacterial dysbiosis. These AMPs appear to contribute to innate immunity in humans, protecting the commensal microflora and restricting the emergence of pathobionts and pathogens. A striking example in human innate immunity is that elevated serum calprotectin protects against neonatal sepsis. Calprotectin is also remarkable because of functional differences when localized in epithelial and neutrophil cytoplasm or released into the extracellular environment. In the cytoplasm, calprotectin appears to protect against invasive pathogens. Extracellularly, calprotectin can engage pathogen-recognition receptors to activate innate immune and proinflammatory mechanisms. In inflamed epithelial and other tissue spaces, calprotectin, DNA, and histones are released from degranulated neutrophils to form insoluble antimicrobial barriers termed neutrophil extracellular traps. Hence, calprotectin and other AMPs use several strategies to provide microbial control and stimulate innate immunity.
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Affiliation(s)
| | - Mark C. Herzberg
- Department of Diagnostic and Biological Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN, United States
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Me R, Gao N, Zhang Y, Lee PSY, Wang J, Liu T, Standiford TJ, Mi QS, Yu FSX. IL-36α Enhances Host Defense against Pseudomonas aeruginosa Keratitis in C57BL/6 Mouse Corneas. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2021; 207:2868-2877. [PMID: 34686582 PMCID: PMC8612993 DOI: 10.4049/jimmunol.2001246] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Accepted: 09/21/2021] [Indexed: 12/13/2022]
Abstract
The IL-36 cytokines are known to play various roles in mediating the immune response to infection in a tissue- and pathogen-dependent manner. The present study seeks to investigate the role of IL-36R signaling in C57BL/6 mouse corneas in response to Pseudomonas aeruginosa infection. IL-36α-/-, IL-36γ-/-, and IL-36R-/- mice had significantly more severe keratitis than wild-type mice. At six hours postinfection, IL-36α pretreatment augmented P. aeruginosa-induced expression of IL-1Ra, IL-36γ, LCN2, and S100A8/A9. At one day postinfection, exogenous IL-36α suppressed, whereas IL-36α deficiency promoted, the expression of IL-1β. At three days postinfection, exogenous IL-36α suppressed Th1 but promoted Th2 immune response. IL-36α stimulated the infiltration of IL-22-expressing immune cells, and IL-22 neutralization resulted in more severe keratitis. IL-36α alone stimulated dendritic cell infiltration in B6 mouse corneas. Taken together, our study suggests that IL-36R signaling plays a protective role in the pathogenesis of P. aeruginosa keratitis by promoting the innate immune defense, Th2, and/or Th22/IL-22 immune responses. Exogenous IL-36α might be a potential therapy for improving the outcome of P. aeruginosa keratitis.
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Affiliation(s)
- Rao Me
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI
| | - Nan Gao
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI
| | - Yangyang Zhang
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI
| | - Patrick S Y Lee
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI
| | - Jie Wang
- Center for Cutaneous Biology and Immunology, Department of Dermatology and Immunology Program, Henry Ford Cancer Institute, Henry Ford Health System, Detroit, MI; and
| | - Tingting Liu
- Center for Cutaneous Biology and Immunology, Department of Dermatology and Immunology Program, Henry Ford Cancer Institute, Henry Ford Health System, Detroit, MI; and
| | - Theodore J Standiford
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI
| | - Qing-Sheng Mi
- Center for Cutaneous Biology and Immunology, Department of Dermatology and Immunology Program, Henry Ford Cancer Institute, Henry Ford Health System, Detroit, MI; and
| | - Fu-Shin X Yu
- Department of Ophthalmology, Visual and Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI;
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Singh RB, Das S, Chodosh J, Sharma N, Zegans ME, Kowalski RP, Jhanji V. Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis. Prog Retin Eye Res 2021; 88:101028. [PMID: 34813978 DOI: 10.1016/j.preteyeres.2021.101028] [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: 07/28/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022]
Abstract
Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the "anti-biotic era". Although, we are expeditiously developing our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins. In this review article, we have provided an overview of the established classical diagnostic techniques and therapeutics for keratitis caused by various bacteria. We have extensively reported our recent in-roads through novel tools for accurate diagnosis of mono- and poly-bacterial corneal infections. Furthermore, we outlined the recent progress by our group and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discussed in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.
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Affiliation(s)
- Rohan Bir Singh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Leiden University Medical Center, 2333, ZA Leiden, the Netherlands
| | - Sujata Das
- Cornea and Anterior Segment Services, LV Prasad Eye Institute, Bhubaneshwar, India
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Namrata Sharma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Michael E Zegans
- Department of Ophthalmology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Regis P Kowalski
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
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8
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Cao S, Dou X, Zhang X, Fang Y, Yang Z, Jiang Y, Hao X, Zhang Z, Wang H. Streptococcus pneumoniae autolysin LytA inhibits ISG15 and ISGylation through decreasing bacterial DNA abnormally accumulated in the cytoplasm of macrophages. Mol Immunol 2021; 140:87-96. [PMID: 34673375 DOI: 10.1016/j.molimm.2021.09.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/05/2021] [Accepted: 09/28/2021] [Indexed: 11/25/2022]
Abstract
Interferon stimulated gene 15 (ISG15) is one of the most robustly upregulated interferon stimulated genes (ISGs) and also a ubiquitin-like modifier which has been reported to play an important role in host defense against pathogens. Cytosolic nucleic acids detected by DNA sensors induce type Ⅰ interferons (IFN-Ⅰs) and ISGs in host cells. Streptococcus pneumoniae (S. pn) autolysin LytA triggers bacterial lysis and then S. pn-derived genomic DNA (hereafter referred to as S. pn-DNA) can be released and accumulates in the cytoplasm of host cells. However, it remains elusive whether LytA-mediated S. pn-DNA release is involved in ISG15 induction. Here we verified that ISG15 conjugation system can be widely activated by S. pn and cytosolic S. pn-DNA in host cells. Moreover, the phagocytosis of macrophages to the mutant strain S. pn D39 ΔlytA was enhanced when compared to S. pn D39, which in turn increased S. pn-DNA uptake into macrophages and augmented ISG15 expression. ISG15 might upregulate proinflammatory cytokines tumor necrosis factor α (TNF-α) and interleukin 1β (IL-1β) in macrophages and further promoted the clearance of S. pn in the absence of LytA. These results indicate that S. pn autolysis blunts ISG15 induction through preventing bacteria internalization and reducing cytosolic S. pn-DNA accumulation in macrophages, revealing a new strategy of S. pn for avoiding elimination. This study will help us to further understand the role of ISG15 during S. pn infection as well as the regulatory mechanisms of immune responses mediated by bacterial autolysis and bacterial DNA.
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Affiliation(s)
- Sijia Cao
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China; Xiamen Maternal and Child Health Care Hospital, Xiamen, 361001 Fujian Province, China
| | - Xiaoyun Dou
- Institute of Life Sciences, Chongqing Medical University, Chongqing, 400016, China
| | - Xuemei Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Yuting Fang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Zihan Yang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Yinting Jiang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Xiaoling Hao
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Ziyuan Zhang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China
| | - Hong Wang
- Key Laboratory of Diagnostic Medicine Designated by the Ministry of Education, Chongqing Medical University, Chongqing, 400016, China; School of Laboratory Medicine, Chongqing Medical University, Chongqing, 400016, China.
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Ung L, Chodosh J. Foundational concepts in the biology of bacterial keratitis. Exp Eye Res 2021; 209:108647. [PMID: 34097906 PMCID: PMC8595513 DOI: 10.1016/j.exer.2021.108647] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/28/2021] [Accepted: 05/27/2021] [Indexed: 12/12/2022]
Abstract
Bacterial infections of the cornea, or bacterial keratitis (BK), are notorious for causing rapidly fulminant disease and permanent vision loss, even among treated patients. In the last sixty years, dramatic upward trajectories in the frequency of BK have been observed internationally, driven in large part by the commercialization of hydrogel contact lenses in the late 1960s. Despite this worsening burden of disease, current evidence-based therapies for BK - including broad-spectrum topical antibiotics and, if indicated, topical corticosteroids - fail to salvage vision in a substantial proportion of affected patients. Amid growing concerns of rapidly diminishing antibiotic utility, there has been renewed interest in urgently needed novel treatments that may improve clinical outcomes on an individual and public health level. Bridging the translational gap in the care of BK requires the identification of new therapeutic targets and rational treatment design, but neither of these aims can be achieved without understanding the complex biological processes that determine how bacterial corneal infections arise, progress, and resolve. In this chapter, we synthesize the current wealth of human and animal experimental data that now inform our understanding of basic BK pathophysiology, in context with modern concepts in ocular immunology and microbiology. By identifying the key molecular determinants of clinical disease, we explore how novel treatments can be developed and translated into routine patient care.
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Affiliation(s)
- Lawson Ung
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Infectious Disease Institute, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA.
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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.
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Trøstrup H, Laulund ASB, Moser C. Insights into Host-Pathogen Interactions in Biofilm-Infected Wounds Reveal Possibilities for New Treatment Strategies. Antibiotics (Basel) 2020; 9:E396. [PMID: 32664205 PMCID: PMC7400121 DOI: 10.3390/antibiotics9070396] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/04/2020] [Accepted: 07/07/2020] [Indexed: 12/26/2022] Open
Abstract
Normal wound healing occurs in three phases-the inflammatory, the proliferative, and the remodeling phase. Chronic wounds are, for unknown reasons, arrested in the inflammatory phase. Bacterial biofilms may cause chronicity by arresting healing in the inflammatory state by mechanisms not fully understood. Pseudomonas aeruginosa, a common wound pathogen with remarkable abilities in avoiding host defense and developing microbial resistance by biofilm formation, is detrimental to wound healing in clinical studies. The host response towards P. aeruginosa biofilm-infection in chronic wounds and impact on wound healing is discussed and compared to our own results in a chronic murine wound model. The impact of P. aeruginosa biofilms can be described by determining alterations in the inflammatory response, growth factor profile, and count of leukocytes in blood. P. aeruginosa biofilms are capable of reducing the host response to the infection, despite a continuously sustained inflammatory reaction and resulting local tissue damage. A recent observation of in vivo synergism between immunomodulatory and antimicrobial S100A8/A9 and ciprofloxacin suggests its possible future therapeutic potential.
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Affiliation(s)
- Hannah Trøstrup
- Department of Plastic Surgery and Breast Surgery, Zealand University Hospital, 4000 Roskilde, Denmark
| | - Anne Sofie Boe Laulund
- Department of Clinical Microbiology, Copenhagen University Hospital, 2200 Copenhagen, Denmark; (A.S.B.L.); (C.M.)
| | - Claus Moser
- Department of Clinical Microbiology, Copenhagen University Hospital, 2200 Copenhagen, Denmark; (A.S.B.L.); (C.M.)
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Gao N, Me R, Dai C, Yu FSX. ISG15 Acts as a Mediator of Innate Immune Response to Pseudomonas aeruginosa Infection in C57BL/6J Mouse Corneas. Invest Ophthalmol Vis Sci 2020; 61:26. [PMID: 32416603 PMCID: PMC7405721 DOI: 10.1167/iovs.61.5.26] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/30/2020] [Indexed: 01/04/2023] Open
Abstract
Purpose IFN-stimulated gene (ISG) 15 is a type 1 IFN-induced protein and known to modify target proteins in a manner similar to ubiquitylation (protein conjugation by ISG15 is termed ISGylation). We sought to determine the role of ISG15 and its underlying mechanisms in corneal innate immune defense against Pseudomonas aeruginosa keratitis. Methods ISG15 expression in cultured human corneal epithelial cells (HCECs) and mouse corneas was determined by PCR and Western blot analysis. Gene knockout mice were used to define the role of ISG15 signaling in controlling the severity of P. aeruginosa keratitis, which was assessed with photographing, clinical scoring, bacterial counting, myeloperoxidase assay, and quantitative PCR determination of cytokine expression. Integrin LFA-1 inhibitor was used to assess its involvement of ISG15 signaling in P. aeruginosa-infected corneas. Results Heat-killed P. aeruginosa induced ISG15 expression in cultured HCECs and accumulation in the conditioned media. Isg15 deficiency accelerated keratitis progress, suppressed IFNγ and CXCL10, and promoted IL-1β while exhibiting no effects on IFNα expression. Moreover, exogenous ISG15 protected the corneas of wild-type mice from P. aeruginosa infection while markedly reducing the severity of P. aeruginosa keratitis in type 1 IFN-receptor knockout mice. Exogenous ISG15 increased bacteriostatic activity of B6 mouse corneal homogenates, and inhibition of LFA-1 exacerbated the severity of and abolished protective effects of ISG15 on P. aeruginosa keratitis. Conclusions Type 1 INF-induced ISG15 regulates the innate immune response and greatly reduces the susceptibility of B6 mouse corneas to P. aeruginosa infection in an LFA-1-dependent manner.
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13
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Gao N, Me R, Dai C, Seyoum B, Yu FSX. Opposing Effects of IL-1Ra and IL-36Ra on Innate Immune Response to Pseudomonas aeruginosa Infection in C57BL/6 Mouse Corneas. THE JOURNAL OF IMMUNOLOGY 2018; 201:688-699. [PMID: 29891552 DOI: 10.4049/jimmunol.1800046] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/16/2018] [Indexed: 12/22/2022]
Abstract
Pseudomonas aeruginosa keratitis is characterized by severe corneal ulceration and may lead to blindness if not treated properly in a timely manner. Although the roles of the IL-1 subfamily of cytokines are well established, as a newly discovered subfamily, IL-36 cytokine regulation, immunological relevance, and relation with IL-1 cytokines in host defense remain largely unknown. In this study, we showed that P. aeruginosa infection induces the expression of IL-36α and IL-36γ, as well as IL-1β and secreted IL-1Ra (sIL-1Ra), but not IL-36Ra. Downregulation of IL-1Ra increases, whereas downregulation of IL-36Ra decreases the severity of P. aeruginosa keratitis. IL-1R and IL-36Ra downregulation have opposing effects on the expression of IL-1β, sIL-1Ra, IL-36γ, S100A8, and CXCL10 and on the infiltration of innate immune cells. Administration of recombinant IL-1Ra improved, whereas IL-36Ra worsened the outcome of P. aeruginosa keratitis. Local application of IL-36γ stimulated the expression of innate defense molecules S100A9, mouse β-defensin 3, but suppressed IL-1β expression in B6 mouse corneas. IL-36γ diminished the severity of P. aeruginosa keratitis, and its protective effects were abolished in the presence of S100A9 neutralizing Ab and partially affected by CXCL10 and CXCR3 neutralizations. Thus, our data reveal that IL-1Ra and IL-36Ra have opposing effects on the outcome of P. aeruginosa keratitis and suggest that IL-36 agonists may be used as an alternative therapeutic to IL-1β-neutralizing reagents in controlling microbial keratitis and other mucosal infections.
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Affiliation(s)
- Nan Gao
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201.,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201
| | - Rao Me
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201.,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201
| | - Chenyang Dai
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201.,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201.,Department of Ophthalmology, Qilu Hospital of Shandong University, Jinan, Shandong Province 250014, China; and
| | - Berhane Seyoum
- Division of Endocrinology, Department of Internal Medicine, Wayne State University School of Medicine, Detroit, MI 48201
| | - Fu-Shin X Yu
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201; .,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201
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Reins RY, Courson J, Lema C, Redfern RL. MyD88 contribution to ocular surface homeostasis. PLoS One 2017; 12:e0182153. [PMID: 28796783 PMCID: PMC5552092 DOI: 10.1371/journal.pone.0182153] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Accepted: 07/13/2017] [Indexed: 12/18/2022] Open
Abstract
The cornea must maintain homeostasis, enabling rapid response to injury and microbial insult, to protect the eye from insult and infection. Toll-like receptors (TLRs) are critical to this innate immune response through the recognition and response to pathogens. Myeloid differentiation primary response (MyD88) is a key signaling molecule necessary for Toll-like receptor (TLR) and interleukin-1 receptor (IL-1R)-mediated immune defense and has been shown to be necessary for corneal defense during infection. Here, we examined the intrinsic role of TLR signaling in ocular surface tissues by determining baseline levels of inflammatory mediators, the response to mechanical stimuli, and corneal infection in MyD88-deficient mice (MyD88-/-). In addition, cytokine, chemokine, and matrix metalloproteinase (MMP) expression was determined in ocular surface cells exposed to a panel of TLR agonists. Compared to wild-type (WT) animals, MyD88-/- mice expressed lower MMP-9 levels in the cornea and conjunctiva. Corneal IL-1α, TNFα, and conjunctival IL-1α, IL-2, IL-6, and IL-9 levels were also significantly reduced. Additionally, CXCL1 and RANTES expression was lower in both MyD88-/- tissues compared to WT and IL-1R-/- mice. Interestingly, MyD88-/- mice had lower corneal sensitivities (1.01±0.31 gm/mm2) than both WT (0.59±0.16 gm/mm2) and IL-1R-/- (0.52±0.08 gm/mm2). Following Pseudomonas aeruginosa challenge, MyD88-/- mice had better clinical scores (0.5±0.0) compared to IL-1R-/- (1.5±0.6) and WT (2.3±0.3) animals, but had significantly more corneal bacterial isolates. However, no signs of infection were detected in inoculated uninjured corneas from either MyD88 or IL-1R-deficient mice. This work furthers our understanding of the importance of TLR signaling in corneal defense and immune homeostasis, showing that a lack of MyD88 may compromise the baseline innate response to insult.
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Affiliation(s)
- Rose Y. Reins
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Justin Courson
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Carolina Lema
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States of America
| | - Rachel L. Redfern
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States of America
- * E-mail:
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15
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Dong C, Gao N, Ross BX, Yu FSX. ISG15 in Host Defense Against Candida albicans Infection in a Mouse Model of Fungal Keratitis. Invest Ophthalmol Vis Sci 2017; 58:2948-2958. [PMID: 28599020 PMCID: PMC5469425 DOI: 10.1167/iovs.17-21476] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Purpose ISG15, a di-ubiquitin-like protein, is critical for controlling certain viral and bacterial infections. We sought to determine if ISG15 plays a role in corneal innate immunity against Candida albicans (C. albicans) using a C57BL/6 (B6) mouse model of human fungal keratitis. Methods Scarified corneas of adult B6 mice were pretreated with TLR5 ligand flagellin and then inoculated with C. albicans. The expression of ISG15 and other genes involved in ISG15 conjugation (ISGylation) was determined by real-time PCR. ISG15 expression and distribution in infected corneas were assessed by immunohistochemistry. ISGylation was examined by Western blotting. siRNA knockdown and recombinant ISG15 were used to elucidate the effects of ISG15 on controlling fungal keratitis by clinical scoring, fungal number plate counting, ELISA cytokine determination, and polymorphonuclear leukocytes (PMN) infiltration measurement. Results Heat-killed C. albicans induced expression of ISG15, and hBD2 was markedly enhanced by flagellin-pretreatment in cultured human primary corneal epithelial cells (CECs). In vivo, C. albicans infection induced the expression of ISG15, ISGylation-associated genes (UBE1L, UBCH8, and HERC5), and ISGylation in mouse CECs, all of which were enhanced by flagellin-pretreatment. siRNA knockdown of ISG15 increased keratitis severity, dampened flagellin-induced protection, and greatly suppressed the expressions of ISGylation enzymes, IFN-γ, but not CXCL2 in B6 mouse CECs. Recombinant ISG15, on the other hand, enhanced corneal innate immunity against C. albicans and suppressed infection-induced IL-1β, but not IL-Ra expression. ISG15 alone induced the expression of IL-1Ra, CXCL10, and CRAMP in mouse CECs. ISG15 was upregulated and secreted in cultured human CECs in response to challenge in a type 1 IFN-dependent manner. Conclusions Our data, for the first time, demonstrate that ISG15 acts as an immunomodulator in the cornea and plays a critical role in controlling fungal keratitis.
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Affiliation(s)
- Chen Dong
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States 2College of Biological Engineering, Henan University of Technology, Zhengzhou, Henan, China
| | - Nan Gao
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Bing X Ross
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States
| | - Fu-Shin X Yu
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan, United States
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Ross BX, Gao N, Cui X, Standiford TJ, Xu J, Yu FSX. IL-24 Promotes Pseudomonas aeruginosa Keratitis in C57BL/6 Mouse Corneas. THE JOURNAL OF IMMUNOLOGY 2017; 198:3536-3547. [PMID: 28330899 DOI: 10.4049/jimmunol.1602087] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 02/27/2017] [Indexed: 01/28/2023]
Abstract
The aim of this study was to elucidate the expression and functions of IL-24 in C57BL/6 mouse corneas in response to Pseudomonas aeruginosa infection. Among IL-20R cytokines, only IL-24 was induced at both mRNA and protein levels by infection at early time points. The upregulation of IL-24 was dampened by flagellin pretreatment, which protects the corneas from microbial infection. Time course studies revealed bimodal early and later peaks of IL-24 expression, a pattern shared with suppressor of cytokine signaling (SOCS)3 but not IL-1β or IL-6. Silencing of IL-24 enhanced S100A8/A9 expression and suppressed SOCS3, IL-1β, IL-1RN, and matrix metalloproteinase 13 expression at 6 h postinfection. Downregulation of the IL-24 signaling pathway significantly reduced the severity of keratitis, whereas rIL-24 exacerbated P. aeruginosa-mediated tissue destruction. In vitro, rIL-1β induced the expression of SOCS3, IL-24, IL-1β, and IL-6 in primary cultured human corneal epithelial cells. rIL-24, alternatively, stimulated the expression of SOCS3, but not the others. In conclusion, IL-24 promotes P. aeruginosa keratitis through the suppression of early protective mucosal immunity, culminating in increased severity of P. aeruginosa keratitis.
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Affiliation(s)
- Bing X Ross
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201.,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201
| | - Nan Gao
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201.,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201
| | - Xinhan Cui
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201.,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201.,Eye and Ear, Nose, and Throat Hospital of Fudan University, Xuhui District, Shanghai 200031, China; and
| | - Theodore J Standiford
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI 48109
| | - Jianjiang Xu
- Eye and Ear, Nose, and Throat Hospital of Fudan University, Xuhui District, Shanghai 200031, China; and
| | - Fu-Shin X Yu
- Department of Ophthalmology, Wayne State University School of Medicine, Detroit, MI 48201; .,Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI 48201
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17
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Wilkinson A, Kawaguchi N, Geczy C, Di Girolamo N. S100A8 and S100A9 proteins are expressed by human corneal stromal dendritic cells. Br J Ophthalmol 2016; 100:1304-8. [DOI: 10.1136/bjophthalmol-2016-308827] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 06/19/2016] [Indexed: 12/24/2022]
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18
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S100A8/A9 is an important host defence mediator in neuropathic foot ulcers in patients with type 2 diabetes mellitus. Arch Dermatol Res 2016; 308:347-55. [PMID: 27084691 DOI: 10.1007/s00403-016-1646-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 02/04/2016] [Accepted: 03/30/2016] [Indexed: 01/13/2023]
Abstract
Chronic wounds and in particular diabetic foot ulcers (DFUs) are a growing clinical challenge, but the underlying molecular pathophysiological mechanisms are unclear. Recently, we reported reduced levels of the immunomodulating and antimicrobial S100A8/A9 in non-healing venous leg ulcers (VLUs), while another study found increased S100A8/A9 in DFUs. To clarify these apparently contradictory findings, we compared S100A8/A9 as well as an inducer, lipopolysaccharide (LPS) and selected innate immune response mediators in wound fluids from non-healing DFUs and VLUs with healing wounds. Wound fluids were collected from neuropathic DFUs (n = 6) and VLUs (n = 9) of median 2-year duration, and split-thickness skin graft donor site wounds (n = 10) by standardized method. None of the patients had ischaemic extremities or clinically infected wounds. LPS was determined by limulus amoebocyte lysate test, and S100A8/A9, granulocyte colony-stimulating factor (G-CSF), interleukin (IL)-10 and vascular endothelial growth factor (VEGF) by immunospecific quantitative assays. LPS levels were median 8.7 (interquartile range 5.4-21.2) ng/ml in DFUs compared with 121 (22-2000) ng/ml in VLUs. S100A8/A9 was higher (p = 0.020) in DFUs [718 (634-811) µg/ml] than in VLUs [303 (252-533) µg/ml]. Neither G-CSF nor IL-10 wound fluid levels differed significantly between the chronic wound groups. VEGF levels correlated with LPS (r = 0.758, p = 0.011, n = 10) and were higher (p = 0.024) in VLU wound fluids. LPS (p < 0.0001), S100A8/A9 (p = 0.005), G-CSF (p = 0.003), IL-10 (p = 0.003) and VEGF (p = 0.005) were increased in chronic wound fluids combined compared with the sterile donor site wound fluids. The protein alterations in the wounds were not reflected in the patients' sera. Low S100A8/A9 levels may contribute to poor wound healing in colonized chronic wounds with striking difference between DFUs and VLUs.
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Chitinase 3-Like 1 Promotes Candida albicans Killing and Preserves Corneal Structure and Function by Controlling Host Antifungal Responses. Infect Immun 2015; 83:4154-64. [PMID: 26238714 DOI: 10.1128/iai.00980-15] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 07/30/2015] [Indexed: 12/17/2022] Open
Abstract
Chitinase 3-like 1 (CHI3L1) has been shown to play a role in promoting antibacterial responses, decreasing tissue injury, and enhancing pulmonary repair. This study sought to elucidate the role of CHI3L1 in augmenting the corneal innate immune response to Candida albicans infection in an animal model of fungal keratitis. Flagellin applied topically 24 h prior to C. albicans inoculation significantly protected the corneal from C. albicans and induced CHI3L1 expression in C57BL/6 mouse corneas. CHI3L1, however, played a detectable but minor role in flagellin-induced protection. While C. albicans keratitis was more severe in the corneas treated with Chi3l1 small interfering RNA (siRNA), corneas treated with recombinant CHI3L1 before C. albicans inoculation had markedly ameliorated keratitis, reduced fungal load, and decreased polymorphonucleocyte (PMN) infiltration in an interleukin 13 receptor α2 (IL-13Rα2)-dependent manner. CHI3L1 treatment resulted in the induction of the antimicrobial peptides β-defensin 3, CRAMP, and chemokine CXCL10 and its receptor CXCR3 in corneal epithelial cells. Importantly, CHI3L1 administered after C. albicans inoculation also had strong protection against fungal keratitis, suggesting a therapeutic window. This is the first report demonstrating that CHI3L1 is induced during fungal infection, where it acts as an immunomodulator to promote fungal clearance and to regulate antifungal innate immune responses in the cornea.
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20
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Gao N, Kumar A, Yu FSX. Matrix Metalloproteinase-13 as a Target for Suppressing Corneal Ulceration Caused by Pseudomonas aeruginosa Infection. J Infect Dis 2015; 212:116-27. [PMID: 25589337 DOI: 10.1093/infdis/jiv016] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Accepted: 12/23/2014] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Pseudomonas aeruginosa keratitis is characterized by severe corneal ulceration. This study investigated whether matrix metalloproteinase-13 (MMP13) is involved in P. aeruginosa-induced corneal ulceration and whether it therefore can be targeted for preventing P. aeruginosa keratitis. METHODS MMP13 expression in P. aeruginosa-infected C57BL/6 mouse corneas was assessed by quantitative polymerase chain reaction and immunohistochemistry analyses. An MMP13-inhibitor (MMP13i) was either injected subconjunctivally prior to or coapplied topically with gatifloxacin 16 hours after infection. Disease severity was assessed by corneal imaging, clinical scoring, bacterial burden, neutrophil infiltration, and CXCL2 expression. Corneal damage and infiltration were also determined by immunohistochemistry analysis and whole-mount confocal microscopy. RESULTS P. aeruginosa infection induced an increased expression of MMP13 in mouse corneas from 6 to 24 hours after infection in a Toll-liked receptor 5-dependent manner. Subconjunctival injection of MMP13i prior to P. aeruginosa inoculation significantly decreased keratitis severity, as evidenced by preserved epithelium integrity and intact basement membrane, leading to reduced bacterial dissemination to the stroma. Furthermore, topical coapplication of MMP13i with gatifloxacin greatly improved disease outcomes, including accelerated opacity dissolution; decreased inflammation, cellular infiltration, and collagen disorganization; and basement membrane preservation. CONCLUSIONS Elevated MMP13 activity may contribute to P. aeruginosa keratitis through basement membrane degradation, and its inhibition could potentially be used as an adjunctive therapy to treat microbial keratitis and other mucosal infections.
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Affiliation(s)
- Nan Gao
- Department of Ophthalmology Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan
| | - Ashok Kumar
- Department of Ophthalmology Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan
| | - Fu-Shin X Yu
- Department of Ophthalmology Department of Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, Michigan
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Liu X, Gao N, Dong C, Zhou L, Mi QS, Standiford TJ, Yu FSX. Flagellin-induced expression of CXCL10 mediates direct fungal killing and recruitment of NK cells to the cornea in response to Candida albicans infection. Eur J Immunol 2014; 44:2667-79. [PMID: 24965580 PMCID: PMC4165733 DOI: 10.1002/eji.201444490] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Revised: 04/29/2014] [Accepted: 06/20/2014] [Indexed: 11/10/2022]
Abstract
We previously showed that topical flagellin induces profound mucosal innate protection in the cornea against microbial infection, a response involving multiple genes and cell types. In this study, we used a Candida albicans (CA)-C57BL/6 mouse keratitis model to delineate the contribution of CXCL10- and CXCR3-expressing cells in flagellin-induced protection. Flagellin pretreatment markedly enhanced CXCL10 expression at 6 h post CA infection (hpi), but significantly dampened CXCL10 expression at 24 hpi. At the cellular level, CXCL10 was expressed in the epithelia at 6 hpi in flagellin-pretreated corneas, and concentrated at lesion sites 24 hpi. CXCR3-expressing cells were detected in great numbers at 24 hpi, organized within clusters at the lesion sites in CA-infected corneas. CXCL10 or CXCR3 neutralization increased keratitis severity and dampened flagellin-induced protection. CXCR3-positive cells were identified as NK cells, the depletion of which resulted in severe CA keratitis. Contributions from NK T-cells were excluded by finding no change in flagellin-induced protection in Rag1 KO mice. Recombinant CXCL10 inhibited CA growth in vitro and accelerated fungal clearance and inflammation resolution in vivo. Taken together, our data indicate that epithelium-expressed CXCL10 plays a critical role in fungal clearance and that CXCR3-expressing NK cells contribute to CA eradication in mouse corneas.
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Affiliation(s)
- Xiaowei Liu
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA
- Department of Ophthalmology, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Nan Gao
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Chen Dong
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA
| | - Li Zhou
- Henry Ford Immunology Program, Department of Dermatology, Department of Internal Medicine, Henry Ford Health System, Detroit, MI, USA
| | - Qing-Sheng Mi
- Henry Ford Immunology Program, Department of Dermatology, Department of Internal Medicine, Henry Ford Health System, Detroit, MI, USA
| | - Theodore J. Standiford
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Fu-Shin X. Yu
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI, USA
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22
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Bettahi I, Sun H, Gao N, Wang F, Mi X, Chen W, Liu Z, Yu FSX. Genome-wide transcriptional analysis of differentially expressed genes in diabetic, healing corneal epithelial cells: hyperglycemia-suppressed TGFβ3 expression contributes to the delay of epithelial wound healing in diabetic corneas. Diabetes 2014; 63:715-27. [PMID: 24306208 PMCID: PMC3900551 DOI: 10.2337/db13-1260] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Patients with diabetes mellitus (DM) may develop corneal complications and delayed wound healing. The aims of this study are to characterize the molecular signatures and biological pathways leading to delayed epithelial wound healing and to delineate the involvement of TGFβ3 therein. Genome-wide cDNA microarray analysis revealed 1,888 differentially expressed genes in the healing epithelia of normal (NL) versus type 1 DM rat corneas. Gene ontology and enrichment analyses indicated TGFβ signaling as a major altered pathway. Among three TGFβ isoforms, TGF-β1 and β3 were upregulated in response to wounding in NL corneal epithelial cells (CECs), whereas the latter was greatly suppressed by hyperglycemia in rat type 1 and 2 and mouse type 1 DM models. Functional analysis indicated that TGF-β3 contributed to wound healing in NL corneas. Moreover, exogenously added TGF-β3 accelerated epithelial wound closure in type 2 rat and type 1 mouse DM corneas via Smad and PI3K-AKT signaling pathways, autoregulation, and/or upregulation of Serpine1, a well-known TGFβ target gene. Taken together, our study for the first time provides a comprehensive list of genes differentially expressed in the healing CECs of NL versus diabetic corneas and suggests the therapeutic potential of TGF-β3 for treating corneal and skin wounds in diabetic patients.
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Affiliation(s)
- Ilham Bettahi
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Haijing Sun
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Nan Gao
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Feng Wang
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Xiaofan Mi
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
| | - Weiping Chen
- Genomic Core Laboratory of National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
| | - Zuguo Liu
- Xiamen Eye Center, Key Laboratory of Ophthalmology and Visual Science of Fujian Province, Xiamen University, Xiamen, Fujian, China
| | - Fu-Shin X. Yu
- Departments of Ophthalmology and Anatomy and Cell Biology, Wayne State University School of Medicine, Detroit, MI
- Corresponding author: Fu-Shin X. Yu,
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23
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Yoon GS, Dong C, Gao N, Kumar A, Standiford TJ, Yu FSX. Interferon regulatory factor-1 in flagellin-induced reprogramming: potential protective role of CXCL10 in cornea innate defense against Pseudomonas aeruginosa infection. Invest Ophthalmol Vis Sci 2013; 54:7510-21. [PMID: 24130180 DOI: 10.1167/iovs.13-12453] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
PURPOSE We previously showed that pre-exposure of the cornea to Toll-like receptor (TLR)5 ligand flagellin induces strong protective innate defense against microbial pathogens and hypothesized that flagellin modulates gene expression at the transcriptional levels. Thus, we sought to determine the role of one transcription factor, interferon regulatory factor (IRF1), and its target gene CXCL10 therein. METHODS Superarray was used to identify transcription factors differentially expressed in Pseudomonas aeruginosa-challenged human corneal epithelial cells (CECs) with or without flagellin pretreatment. The expression of CXCL10, IRF1, LI-8(CXCL2), and IFNγ was determined by PCR, immunohistochemistry, Western/dot blotting, and/or ELISA. IRF1 knockout mice, CXCL10 and IFNγ neutralization, and NK cell depletion were used to define in vivo regulation and function of CXCL10. The severity of P. aeruginosa was assessed using clinical scoring, slit-lamp microscopy, bacterial counting, polymorphonuclear leukocytes (PMN) infiltration, and macrophage inflammatory protein 2/Chemokine (C-X-C motif) ligand 2 (MIP-2/CXCL2) expression. RESULTS Flagellin pretreatment drastically affected P. aeruginosa-induced IRF1 expression in human CECs. However, flagellin pretreatment augmented the P. aeruginosa-induced expression of Irf1 and its target gene Cxcl10 in B6 mouse corneas. Irf1 deficiency reduced infection-triggered CXCL10 expression, increased keratitis severity, and attenuated flagellin-elicited protection compared to values in wild-type (WT) controls. CXCL10 neutralization in the cornea of WT mice displayed pathogenesis similar to that of IRF1⁻/⁻ mice. IFNγ receptor neutralization and NK cell depletion prevented flagellin-augmented IRF1 and CXCL10 expression and increased the susceptibility to P. aeruginosa infection in mouse corneas. CONCLUSIONS IRF1 plays a role in the corneal innate immune response by regulating CXCL10 expression. IFNγ-producing NK cells augment the epithelial expression of IRF1 and CXCL10 and thus contribute to the innate defense of the cornea against P. aeruginosa infection.
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Affiliation(s)
- Gi Sang Yoon
- Department of Anatomy and Cell Biology, Kresge Eye Institute, Wayne State University, Detroit, Michigan
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