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Mpakosi A, Kaliouli-Antonopoulou C. Immune Mechanisms of Filamentous Fungal Keratitis. Cureus 2024; 16:e61954. [PMID: 38855487 PMCID: PMC11162199 DOI: 10.7759/cureus.61954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2024] [Indexed: 06/11/2024] Open
Abstract
Filamentous fungal keratitis is a particularly serious eye infection that often results in ulceration, corneal perforation, and blindness. The cornea acts as a natural barrier against harmful agents due to the close connection of its epithelial cells. In addition, on its surface, there is a large number of substances with anti-inflammatory and bactericidal properties, such as secretory IgA and mucin glycoproteins, and antimicrobial peptides (AMPs), such as human β-defensin 2 (HBD-2) and LL-37, which are especially increased in filamentous fungal keratitis. The interaction between pathogenic fungi and the host's immune mechanisms is a complex process: pathogen-associated molecular pattern (PAMP) molecules (chitin, β-glucan, and mannan) found in the fungal cell wall are recognized by pattern recognition receptors (PRRs) (toll-like receptors {TLRs}, C-type lectin receptors {CLRs}, nucleotide-binding oligomerization domain-like receptors {NLRs}, and scavenger receptors {SR}) found in host defense cells, triggering the secretion of various types of cytokines, such as interleukins (IL), tumor necrosis factors (TNFs), and chemokines, which recruit macrophages and neutrophils to migrate to the site of infection and activate inflammatory responses. In addition, the interaction of hyphae and corneal epithelial cells can activate cluster of differentiation (CD) 4+ T cells, CD8+ T cells, and B cells and induce secretion of T-helper (Th)-type cytokines 2 (IL-4 and IL-13) and IgG.
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Affiliation(s)
- Alexandra Mpakosi
- Department of Microbiology, General Hospital of Nikaia "Agios Panteleimon", Piraeus, GRC
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Zhu G, Lyu L, Yang H, Lee J, Sun J, Zhang J, Xue S, Yan H, Wang L, Chen X, Che C. CLEC-1 Acts as a Negative Regulator of Dectin-1 Induced Host Inflammatory Response Signature in Aspergillus fumigatus Keratitis. Invest Ophthalmol Vis Sci 2021; 62:28. [PMID: 34043748 PMCID: PMC8164365 DOI: 10.1167/iovs.62.6.28] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose C-type lectin-like receptor-1 (CLEC-1) is a member of the Dectin-1 cluster of pattern recognition receptors (PRRs). It is involved in host immunity, has immunoregulatory function, and supports allograft tolerance. Our study aimed to describe the role of CLEC-1 in response to fungal keratitis, in situ, in vivo, and in vitro. Methods Quantitative polymerase chain reaction (qRT-PCR) and immunofluorescence were used to detect the expression of CLEC-1 in corneas of patients with Aspergillus fumigatus (A. fumigatus) keratitis. In vitro and in vivo experiments were designed in THP-1 macrophages and C57BL/6 mouse models, respectively. The expression of CLEC-1 in corneas of mice model was determined by qRT-PCR, Western blot, and immunofluorescence. CLEC-1 overexpression in mouse corneas was achieved by intrastromal injection of adeno-associated virus (AAV) vectors. Disease response was evaluated by slit-lamp photography, clinical score, and colony forming unit (CFU). Bioluminescence imaging system image acquisition, myeloperoxidase (MPO) assays, immunofluorescence staining, qRT-PCR, and Western blot were used to investigate the role of CLEC-1. To further define the role of CLEC-1, we used lentivirus vectors to overexpress CLEC-1 or/and Dectin-1 in THP-1 macrophages. Results The expression of CLEC-1 was increased in corneas of patients with A. fumigatus keratitis. In corneas of mice from the A. fumigatus keratitis model, the expression of CLEC-1 was decreased in the acute inflammatory stage and increased during convalescence. Following Natamycin treatment, CLEC-1 was upregulated in A. fumigatus keratitis mice. Compared with normal C57BL/6 mice, overexpression of CLEC-1 converted the characteristic susceptible response to resistance, as demonstrated by slit-lamp photography and clinical score. In vivo studies revealed decreased MPO levels and neutrophils recruitment and higher fungal load after the upregulation of CLEC-1. Compared with control corneas, CLEC-1 overexpression impaired corneal pro-inflammatory cytokine IL-1β production. Conclusions These findings demonstrate that CLEC-1 may act as a negative regulator of Dectin-1 induced host inflammatory response via suppressing neutrophils recruitment and production of pro-inflammatory cytokine IL-1β production in response to A. fumigatus keratitis.
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Affiliation(s)
- Guoqiang Zhu
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China.,Department of Ophthalmology, the Affiliated Hospital of Jining Medical University, Jining, China
| | - Leyu Lyu
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Hua Yang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jieun Lee
- Department of Ophthalmology, School of Medicine, Pusan National University, Yangsan, Korea
| | - Jintao Sun
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Jie Zhang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Shasha Xue
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Haijing Yan
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Limei Wang
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Xiaomeng Chen
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
| | - Chengye Che
- Department of Ophthalmology, the Affiliated Hospital of Qingdao University, Qingdao, China
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Han F, Guo H, Wang L, Zhang Y, Sun L, Dai C, Wu X. TSLP Produced by Aspergillus fumigatus-Stimulated DCs Promotes a Th17 Response Through the JAK/STAT Signaling Pathway in Fungal Keratitis. Invest Ophthalmol Vis Sci 2020; 61:24. [PMID: 33346778 PMCID: PMC7757613 DOI: 10.1167/iovs.61.14.24] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to explore the role of thymic stromal lymphopoietin (TSLP) secreted by Aspergillus fumigatus–stimulated dendritic cells (DCs) during the T helper 17 (Th17) immune response, and further clarify the mechanisms contributing to the Th17 immune response of fungal keratitis (FK). Methods A carboxyfluorescein diacetate succinimidyl ester assay, PCR, and flow cytometry were performed to detect Th17 differentiation of CD4+ T cells; PCR, ELISA, and Western blot were used to detect the expression of TSLP and JAK/STAT–related proteins; Signaling pathways involved in Th17 response was evaluated using RNA sequence; C57BL/6 mice were infected with A. fumigatus and treated with ruxolitinib or BBI608. Slit-lamp examination, fluorescein staining, and clinical scores were used to assess the clinical manifestation. Results A. fumigatus–infected DCs could drive naïve CD4+ T-cell proliferation and promote the production of Th17 cytokines IL-17A, IL-17F, and IL-22. A. fumigatus stimulation increased the expression of TSLP in DCs. DC-derived TSLP contributed to a Th17-type inflammatory response via the JAK/STAT signaling pathway. TSLP small interfering RNA, TSLPR small interfering RNA, or JAK/STAT inhibitors inhibited the Th17 immune response induced by A. fumigatus–infected DCs. Moreover, TSLP promoted A. fumigatus keratitis disease progression in a mouse model. However, inhibition of the JAK/STAT signaling pathway using a specific inhibitor reversed the development of FK by A. fumigatus infection. Conclusions TSLP secreted by A. fumigatus–stimulated DCs played a significant role in the Th17-dominant immune response of FK through its JAK/STAT activation. Our findings may contribute to the elucidation of the molecular mechanisms of FK and to the development of novel therapeutic approaches.
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Affiliation(s)
- Fang Han
- Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, 250012, China.,The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital, Shandong University, Jinan 250012, China
| | - Hui Guo
- Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, 250012, China
| | - Leyi Wang
- Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, 250012, China
| | - Yuting Zhang
- Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, 250012, China
| | - Lin Sun
- Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, 250012, China.,The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital, Shandong University, Jinan 250012, China
| | - Chenyang Dai
- Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, 250012, China.,The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education and Chinese Ministry of Health, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Qilu Hospital, Shandong University, Jinan 250012, China
| | - Xinyi Wu
- Department of Ophthalmology, Qilu Hospital, Shandong University, Jinan, 250012, China
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