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Rayamajhee B, Willcox M, Henriquez FL, Vijay AK, Petsoglou C, Shrestha GS, Peguda HK, Carnt N. The role of naturally acquired intracellular Pseudomonas aeruginosa in the development of Acanthamoeba keratitis in an animal model. PLoS Negl Trop Dis 2024; 18:e0011878. [PMID: 38166139 PMCID: PMC10795995 DOI: 10.1371/journal.pntd.0011878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Revised: 01/18/2024] [Accepted: 12/21/2023] [Indexed: 01/04/2024] Open
Abstract
BACKGROUND Acanthamoeba is an environmental host for various microorganisms. Acanthamoeba is also becoming an increasingly important pathogen as a cause of keratitis. In Acanthamoeba keratitis (AK), coinfections involving pathogenic bacteria have been reported, potentially attributed to the carriage of microbes by Acanthamoeba. This study assessed the presence of intracellular bacteria in Acanthamoeba species recovered from domestic tap water and corneas of two different AK patients and examined the impact of naturally occurring intracellular bacteria within Acanthamoeba on the severity of corneal infections in rats. METHODOLOGY/PRINCIPAL FINDINGS Household water and corneal swabs were collected from AK patients. Acanthamoeba strains and genotypes were confirmed by sequencing. Acanthamoeba isolates were assessed for the presence of intracellular bacteria using sequencing, fluorescence in situ hybridization (FISH), and electron microscopy. The viability of the bacteria in Acanthamoeba was assessed by labelling with alkyne-functionalized D-alanine (alkDala). Primary human macrophages were used to compare the intracellular survival and replication of the endosymbiotic Pseudomonas aeruginosa and a wild type strain. Eyes of rats were challenged intrastromally with Acanthamoeba containing or devoid of P. aeruginosa and evaluated for the clinical response. Domestic water and corneal swabs were positive for Acanthamoeba. Both strains belonged to genotype T4F. One of the Acanthamoeba isolates harboured P. aeruginosa which was seen throughout the Acanthamoeba's cytoplasm. It was metabolically active and could be seen undergoing binary fission. This motile strain was able to replicate in macrophage to a greater degree than strain PAO1 (p<0.05). Inoculation of Acanthamoeba containing the intracellular P. aeruginosa in rats eyes resulted in a severe keratitis with increased neutrophil response. Acanthamoeba alone induced milder keratitis. CONCLUSIONS/SIGNIFICANCE Our findings indicate the presence of live intracellular bacteria in Acanthamoeba can increase the severity of acute keratitis in vivo. As P. aeruginosa is a common cause of keratitis, this may indicate the potential for these intracellular bacteria in Acanthamoeba to lead to severe polymicrobial keratitis.
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Affiliation(s)
- Binod Rayamajhee
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| | - Mark Willcox
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| | - Fiona L. Henriquez
- School of Health and Life Sciences, University of the West of Scotland, Blantyre, Scotland, United Kingdom
| | - Ajay Kumar Vijay
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| | - Constantinos Petsoglou
- Sydney and Sydney Eye Hospital, Southeastern Sydney Local Health District, Sydney, Australia
- Save Sight Institute, University of Sydney, Sydney, Australia
| | - Gauri Shankar Shrestha
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| | - Hari Kumar Peguda
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
| | - Nicole Carnt
- School of Optometry and Vision Science, Faculty of Medicine and Health, UNSW, Sydney, Australia
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Konda N, Chakrabarti S, Garg P, Willcox MDP. Association of Single-Nucleotide Polymorphisms in Interleukin Genes with Microbial Keratitis in a South Indian Population. Pathogens 2022; 11:1387. [PMID: 36422638 PMCID: PMC9692714 DOI: 10.3390/pathogens11111387] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/12/2022] [Accepted: 11/19/2022] [Indexed: 05/03/2024] Open
Abstract
BACKGROUND To examine the relationship between single-nucleotide polymorphisms (SNPs) in interleukin (IL) genes and keratitis and its clinical manifestations. METHODS SNPs in IL1B, IL6, CXCL8, IL10, and IL12B were analysed. Differences in frequencies of alleles, genotypes and haplotypes between cases and controls as well as associations between SNPs and clinical variables were calculated by χ2 tests with odds ratios. RESULTS The minor homologous genotype in IL1B rs16944 (p = 0.036; odds ratio (OR) = 2.063, 95% confidence interval (CI): 1.048-4.061) and CXCL8 rs4073 (p = 0.041; OR = 0.463, 95% CI: 0.224-0.956) and the heterologous genotypes in IL6 rs1800795 (p = 0.046; OR = 0.563, 95% CI: 0.326-0.972) and IL12B rs2569254 (p = 0.0446; OR = 0.557, 95% CI: 0.314-0.989) or rs730691 (p = 0.0051; OR = 0.451, 95% CI: 0.260-0.784) were associated with keratitis. The minor genotype of rs16944 was associated with severe infection (p = 0.046). The heterologous genotype in rs2569254 was associated with hospital admission, photophobia, and mode of contact lens wear (p ≤ 0.041). The heterologous genotype in rs730691 was associated with blurred vision, discharge, anterior chamber reaction, and mode of wear (p ≤ 0.047). CONCLUSIONS This study demonstrates that SNPs in IL1B and CXCL8 are associated with risk of developing keratitis. The study also found relationships between SNPs and clinical measures of keratitis. The potential for ethnic differences in frequency of SNPs and their association with keratitis should be followed up using different populations.
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Affiliation(s)
- Nagaraju Konda
- School of Optometry and Vision Science, University of New South Wales, Sydney 2052, Australia
- Brien Holden Vision Institute, Sydney 2052, Australia
- School of Medical Sciences, University of Hyderabad, Hyderabad 500046, Telangana, India
| | - Subhabrata Chakrabarti
- Brien Holden Eye Research Centre, L. V. Prasad Eye Institute, Hyderabad 500034, Telangana, India
| | - Prashant Garg
- The Cornea Institute, L. V. Prasad Eye Institute, Hyderabad, Telangana 500034, India
| | - Mark D. P. Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney 2052, Australia
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Clemens LE, Jaynes J, Lim E, Kolar SS, Reins RY, Baidouri H, Hanlon S, McDermott AM, Woodburn KW. Designed Host Defense Peptides for the Treatment of Bacterial Keratitis. Invest Ophthalmol Vis Sci 2017; 58:6273-6281. [PMID: 29242901 PMCID: PMC5730364 DOI: 10.1167/iovs.17-22243] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 11/08/2017] [Indexed: 11/24/2022] Open
Abstract
Purpose To limit corneal damage and potential loss of vision, bacterial keratitis must be treated aggressively. Innovation in antimicrobials is required due to the need for empirical treatment and the rapid emergence of bacterial resistance. Designed host defense peptides (dHDPs) are synthetic analogues of naturally occurring HDPs, which provide defense against invading pathogens. This study investigates the use of novel dHDPs for the treatment of bacterial keratitis. Methods The minimum inhibitory concentrations (MICs) were determined for dHDPs on both Gram-positive and -negative bacteria. The minimum biofilm eradication concentrations (MBEC) and in vitro time-kill assays were determined. The most active dHDP, RP444, was evaluated for propensity to induce drug resistance and therapeutic benefit in a murine Pseudomonas aeruginosa keratitis model. Results Designed HDPs were bactericidal with MICs ranging from 2 to >64 μg/mL and MBEC ranging from 6 to 750 μg/mL. In time-kill assays, dHDPs were able to rapidly reduce bacterial counts upon contact with as little as 2 μg/mL. RP444 did not induce resistance after repeated exposure of P. aeruginosa to subinhibitory concentrations. RP444 demonstrated significant efficacy in a murine model of bacterial keratitis as evidenced by a significant dose-dependent decrease in ocular clinical scores, a significantly reduced bacterial load, and substantially decreased inflammatory cell infiltrates. Conclusions Innovative dHDPs demonstrated potent antimicrobial activity, possess a limited potential for development of resistance, and reduced the severity of murine P. aeruginosa keratitis. These studies demonstrate that a novel dHDP may have potential to treat patients with sight-threatening bacterial keratitis.
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Affiliation(s)
| | - Jesse Jaynes
- Integrative Biosciences, Tuskegee University, Tuskegee, Alabama, United States
| | - Edward Lim
- Lumigenics LLC, Richmond, California, United States
| | - Satya S. Kolar
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States
| | - Rose Y. Reins
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States
| | - Hasna Baidouri
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States
| | - Samuel Hanlon
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States
| | - Alison M. McDermott
- The Ocular Surface Institute, College of Optometry, University of Houston, Houston, Texas, United States
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Yimin, Kohanawa M, Zhao S, Li M, Kuge Y, Tamaki N, Watanabe M. Regulatory Effect of Interleukin-4 in the Innate Inflammatory Response toRhodococcus aurantiacusInfection in Mice. J Interferon Cytokine Res 2015; 35:222-31. [DOI: 10.1089/jir.2014.0107] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Yimin
- Department of Advanced Medicine, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Masashi Kohanawa
- Department of Advanced Medicine, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Songji Zhao
- Department of Tracer Kinetics and Bioanalysis, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Minqi Li
- Department of Bone Metabolism, School of Stomatology, Shandong University, Jinan, China
| | - Yuji Kuge
- Central Institute of Isotope Science, Hokkaido University, Sapporo, Japan
| | - Nagara Tamaki
- Department of Nuclear Medicine, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Advanced Medicine, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
- Department of Anatomy, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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Kolar SSN, Luca V, Baidouri H, Mannino G, McDermott AM, Mangoni ML. Esculentin-1a(1-21)NH2: a frog skin-derived peptide for microbial keratitis. Cell Mol Life Sci 2014; 72:617-627. [PMID: 25086859 DOI: 10.1007/s00018-014-1694-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 07/17/2014] [Accepted: 07/24/2014] [Indexed: 01/09/2023]
Abstract
Pseudomonas aeruginosa is the primary bacterial pathogen causing contact lens related keratitis. Available ophthalmic agents have reduced efficacy and antimicrobial peptides (AMPs) hold promise as future antibiotics. Here we investigated the in vitro and in vivo anti-Pseudomonal activity of esculentin-1a(1-21)NH2, derived from a frog skin AMP. The data revealed a minimum inhibitory concentration between 2 and 16 μM against reference strains or drug-resistant clinical isolates of P. aeruginosa without showing toxicity to human corneal epithelial cells up to 50 μM. At 1 μM the peptide rapidly killed bacterial cells and this activity was fully retained in 150 mM sodium chloride and 70 % (v/v) human basal tears, particularly against the virulent ATCC 19660 strain. Furthermore, its dropwise administration at 40 μM to the ocular surface in a murine model of P. aeruginosa keratitis (three times daily, for 5 days post-infection) resulted in a significant reduction of infection. The mean clinical score was 2.89 ± 0.26 compared to 3.92 ± 0.08 for the vehicle control. In addition, the corneal level of viable bacteria in the peptide treated animals was significantly lower with a difference of 4 log10 colony counts, compared to 7.7 log10 cells recovered in the control. In parallel, recruitment of inflammatory cells was reduced by half compared to that found in the untreated eyes. Similar results were obtained when esculentin-1a(1-21)NH2 was applied prior to induction of keratitis. Overall, our findings highlight esculentin-1a(1-21)NH2 as an attractive candidate for the development of novel topical pharmaceuticals against Pseudomonas keratitis.
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Affiliation(s)
- Satya Sree N Kolar
- College of Optometry, The Ocular Surface Institute, University of Houston, Houston, TX, USA
| | - Vincenzo Luca
- Department of Biochemical Sciences "A. Rossi Fanelli", Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Via degli Apuli 9, 00185, Rome, Italy
| | - Hasna Baidouri
- College of Optometry, The Ocular Surface Institute, University of Houston, Houston, TX, USA
| | - Giuseppe Mannino
- Ophthalmology Unit, NESMOS Department, S. Andrea Hospital, Faculty of Medicine and Psychology, Sapienza University of Rome, Rome, Italy
| | - Alison M McDermott
- College of Optometry, The Ocular Surface Institute, University of Houston, Houston, TX, USA
| | - Maria Luisa Mangoni
- Department of Biochemical Sciences "A. Rossi Fanelli", Istituto Pasteur-Fondazione Cenci Bolognetti, Sapienza University of Rome, Via degli Apuli 9, 00185, Rome, Italy.
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Protective role of murine β-defensins 3 and 4 and cathelin-related antimicrobial peptide in Fusarium solani keratitis. Infect Immun 2013; 81:2669-77. [PMID: 23670560 DOI: 10.1128/iai.00179-13] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Antimicrobial peptides (AMPs), such as β-defensins and cathelicidins, are essential components of innate and adaptive immunity owing to their extensive multifunctional activities. However, their role in fungal infection in vivo remains elusive. In this study, we investigated the protective effect of murine β-defensin 3 (mBD3), mBD4, and the cathelicidin cathelin-related antimicrobial peptide (CRAMP) in a murine model of Fusarium solani keratitis. C57BL/6 mice showed significant corneal disease 1 and 3 days after infection, which was accompanied by enhanced expression of β-defensins and CRAMP. Disease severity was significantly improved 7 days after infection, at which time AMP expression was returning to baseline. Mice deficient in mBD3 (genetic knockout), mBD4 (short interfering RNA knockdown), or CRAMP (genetic knockout) exhibited enhanced disease severity and progression, increased neutrophil recruitment, and delayed pathogen elimination compared to controls. Taken together, these data suggest a vital role for AMPs in defense against F. solani keratitis, a potentially blinding corneal disease.
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Cole N, Hume EB, Khan S, Garthwaite L, Schubert T, Reeve V, Willcox MDP. The corneal response to infection withStaphylococcus aureusin the absence of interleukin‐4. Immunol Cell Biol 2007; 85:333-7. [PMID: 17389870 DOI: 10.1038/sj.icb.7100043] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Interleukin-4 (IL-4) has previously been implicated in a protective response to Staphylococcus aureus corneal infection. Consequently, the specific role of IL-4 during S. aureus corneal infection was investigated using IL-4 gene knockout mice. The eyes of IL-4-/- mice and wild-type mice were challenged topically with S. aureus and examined at 24 h post-infection. Keratitis was examined clinically and histologically. Bacterial and polymorphonuclear leucocytes (PMN) numbers were enumerated and cytokine and chemokine levels determined by enzyme-linked immunosorbent assay. Exogenous IL-4 was administered to both IL-4-/- and wild-type mice and clinical parameters were determined. A lack of IL-4 resulted in a significant increase in clinical scores, pathology, bacterial load and neutrophil numbers. The absence of IL-4 also resulted in an upregulation of interferon (IFN)-gamma and a downregulation of IL-6, IL-10 and the chemokines KC and macrophage inflammatory protein-2. Administration of exogenous IL-4 to IL-4-/- mice was protective but time-dependent. This study highlights the protective role of IL-4 during S. aureus infection and emphasizes the balance between IL-4 and IFN-gamma in achieving bacterial control and maintaining the integrity of the cornea. This information may lead to the development of novel therapeutic strategies potentially improving the prognosis for infection of this unique avascular site.
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Affiliation(s)
- Nerida Cole
- Institute for Eye Research, University of New South Wales, Sydney, NSW 2052, Australia
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