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Edvardsen PKT, Askarian F, Zurich R, Nizet V, Vaaje-Kolstad G. Exploring roles of the chitinase ChiC in modulating Pseudomonas aeruginosa virulence phenotypes. Microbiol Spectr 2024; 12:e0054624. [PMID: 38819151 PMCID: PMC11218509 DOI: 10.1128/spectrum.00546-24] [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: 02/29/2024] [Accepted: 04/23/2024] [Indexed: 06/01/2024] Open
Abstract
Chitinases are ubiquitous enzymes involved in biomass degradation and chitin turnover in nature. Pseudomonas aeruginosa (PA), an opportunistic human pathogen, expresses ChiC, a secreted glycoside hydrolase 18 family chitinase. Despite speculation about ChiC's role in PA disease pathogenesis, there is scant evidence supporting this hypothesis. Since PA cannot catabolize chitin, we investigated the potential function(s) of ChiC in PA pathophysiology. Our findings show that ChiC exhibits activity against both insoluble (α- and β-chitin) and soluble chitooligosaccharides. Enzyme kinetics toward (GlcNAc)4 revealed a kcat of 6.50 s-1 and a KM of 1.38 mM, the latter remarkably high for a canonical chitinase. In our label-free proteomics investigation, ChiC was among the most abundant proteins in the Pel biofilm, suggesting a potential contribution to PA biofilm formation. Using an intratracheal challenge model of PA pneumonia, the chiC::ISphoA/hah transposon insertion mutant paradoxically showed slightly increased virulence compared to the wild-type parent strain. Our results indicate that ChiC is a genuine chitinase that contributes to a PA pathoadaptive pathway.IMPORTANCEIn addition to performing chitin degradation, chitinases from the glycoside hydrolase 18 family have been found to play important roles during pathogenic bacterial infection. Pseudomonas aeruginosa is an opportunistic pathogen capable of causing pneumonia in immunocompromised individuals. Despite not being able to grow on chitin, the bacterium produces a chitinase (ChiC) with hitherto unknown function. This study describes an in-depth characterization of ChiC, focusing on its potential contribution to the bacterium's disease-causing ability. We demonstrate that ChiC can degrade both polymeric chitin and chitooligosaccharides, and proteomic analysis of Pseudomonas aeruginosa biofilm revealed an abundance of ChiC, hinting at a potential role in biofilm formation. Surprisingly, a mutant strain incapable of ChiC production showed higher virulence than the wild-type strain. While ChiC appears to be a genuine chitinase, further investigation is required to fully elucidate its contribution to Pseudomonas aeruginosa virulence, an important task given the evident health risk posed by this bacterium.
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Affiliation(s)
| | - Fatemeh Askarian
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego School of Medicine, La Jolla, California, USA
| | - Raymond Zurich
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego School of Medicine, La Jolla, California, USA
| | - Victor Nizet
- Division of Host-Microbe Systems & Therapeutics, Department of Pediatrics, UC San Diego School of Medicine, La Jolla, California, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, UC San Diego, La Jolla, California, USA
| | - Gustav Vaaje-Kolstad
- Faculty of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, Ås, Norway
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Done RE, Robertson JK, Prezioso SM, Goldberg JB. LasR regulates protease IV expression at suboptimal growth temperatures in Pseudomonas aeruginosa. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.27.601069. [PMID: 38979315 PMCID: PMC11230357 DOI: 10.1101/2024.06.27.601069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
The opportunistic pathogen Pseudomonas aeruginosa causes debilitating lung infections in people with cystic fibrosis, as well as eye, burn, and wound infections in otherwise immunocompetent individuals. Many of P. aeruginosa's virulence factors are regulated by environmental changes associated with human infection, such as a change in temperature from ambient to human body temperature. One such virulence factor is protease IV (PIV). Interestingly, piv expression is higher at ambient temperatures (22-28°C) compared to human body temperature (37°C). We found that piv expression was thermoregulated at stationary phase, but not exponential phase, and that piv is thermoregulated at the level of transcription. Protein levels of known transcriptional regulators of piv, the quorum sensing regulator LasR and the gene-silencing histone nucleoid silencing proteins MvaT/MvaU, were not thermoregulated. Using a transcriptional reporter for piv, we show that LasR activates piv expression at stationary phase at 25°C but not 37°C, while MvaT/MvaU are not required for piv thermoregulation. We also identified a las box in the piv promoter, which is important for piv thermoregulation. We propose that LasR directly regulates piv at stationary phase at 25°C but has a negligible impact at 37°C. Here, we show that piv is uniquely regulated by LasR in a temperature-dependent manner. Our findings suggest that the LasRI quorum sensing regulon of P. aeruginosa may not be fully characterized and that growth at non-standard laboratory conditions such as lower temperatures could reveal previously unrecognized quorum sensing regulated genes.
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Affiliation(s)
- Rachel E. Done
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
- Department of Pediatrics, Division of Pulmonary, Asthma, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, Georgia, USA
| | | | - Samantha M. Prezioso
- Microbiology and Molecular Genetics Program, Graduate Division of Biological and Biomedical Sciences, Laney Graduate School, Emory University, Atlanta, Georgia, USA
- Department of Pediatrics, Division of Pulmonary, Asthma, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, Georgia, USA
| | - Joanna B. Goldberg
- Department of Pediatrics, Division of Pulmonary, Asthma, Cystic Fibrosis, and Sleep, Emory University School of Medicine, Atlanta, Georgia, USA
- Emory+Children’s Center for Cystic Fibrosis and Airway Disease Research, Emory University School of Medicine, Atlanta, Georgia, USA
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Ambreetha S, Zincke D, Balachandar D, Mathee K. Genomic and metabolic versatility of Pseudomonas aeruginosa contributes to its inter-kingdom transmission and survival. J Med Microbiol 2024; 73. [PMID: 38362900 DOI: 10.1099/jmm.0.001791] [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] [Indexed: 02/17/2024] Open
Abstract
Pseudomonas aeruginosa is one of the most versatile bacteria with renowned pathogenicity and extensive drug resistance. The diverse habitats of this bacterium include fresh, saline and drainage waters, soil, moist surfaces, taps, showerheads, pipelines, medical implants, nematodes, insects, plants, animals, birds and humans. The arsenal of virulence factors produced by P. aeruginosa includes pyocyanin, rhamnolipids, siderophores, lytic enzymes, toxins and polysaccharides. All these virulent elements coupled with intrinsic, adaptive and acquired antibiotic resistance facilitate persistent colonization and lethal infections in different hosts. To date, treating pulmonary diseases remains complicated due to the chronic secondary infections triggered by hospital-acquired P. aeruginosa. On the contrary, this bacterium can improve plant growth by suppressing phytopathogens and insects. Notably, P. aeruginosa is one of the very few bacteria capable of trans-kingdom transmission and infection. Transfer of P. aeruginosa strains from plant materials to hospital wards, animals to humans, and humans to their pets occurs relatively often. Recently, we have identified that plant-associated P. aeruginosa strains could be pathologically similar to clinical isolates. In this review, we have highlighted the genomic and metabolic factors that facilitate the dominance of P. aeruginosa across different biological kingdoms and the varying roles of this bacterium in plant and human health.
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Affiliation(s)
- Sakthivel Ambreetha
- Developmental Biology and Genetics, Division of Biological Sciences, Indian Institute of Science, Bengaluru, Karnataka, 560012, India
| | - Diansy Zincke
- Emerging Pathogens Institute, University of Florida, Gainesville, FL 32610, USA
| | - Dananjeyan Balachandar
- Department of Agricultural Microbiology, Tamil Nadu Agricultural University, Coimbatore, 641003, Tamil Nadu, India
| | - Kalai Mathee
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
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4
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Fortuna A, Collalto D, Rampioni G, Leoni L. Assays for Studying Pseudomonas aeruginosa Secreted Proteases. Methods Mol Biol 2024; 2721:137-151. [PMID: 37819520 DOI: 10.1007/978-1-0716-3473-8_10] [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] [Indexed: 10/13/2023]
Abstract
Proteolytic activity plays an essential role in Pseudomonas aeruginosa adaptation and survival in challenging environments, including the infection site. Here, a short review of the eight known proteases secreted by P. aeruginosa and of the methods used to detect their activity is provided. In addition, three simple and handy methods routinely used in our laboratory to detect proteases are described in detail. In particular, the skim milk plate assay and the azocasein assay are useful for the detection of whole proteases activity in colony-growing and cell-free culture supernatants, respectively. Conversely, the Elastin Congo-red assay allows detecting the activity of the LasB elastase, the major protease secreted by P. aeruginosa, in cell-free culture supernatants.
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Affiliation(s)
| | | | - Giordano Rampioni
- Department of Science, University Roma Tre, Rome, Italy
- IRCCS Fondazione Santa Lucia, Rome, Italy
| | - Livia Leoni
- Department of Science, University Roma Tre, Rome, Italy.
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Shanks RMQ, Atta S, Stella NA, Sundar-Raj CV, Romanowski JE, Grewal AS, Shanks HQ, Mumper SM, Dhaliwal DK, Mammen A, Callaghan JD, Calvario RC, Romanowski EG, Kowalski RP, Zegans ME, Jhanji V. A rise in the frequency of lasR mutant Pseudomonas aeruginosa among keratitis isolates between 1993 and 2021. Front Cell Infect Microbiol 2023; 13:1286842. [PMID: 38029269 PMCID: PMC10651084 DOI: 10.3389/fcimb.2023.1286842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023] Open
Abstract
Introduction Pseudomonas aeruginosa causes vision threatening keratitis. The LasR transcription factor regulates virulence factors in response to the quorum sensing molecule N-3-oxo-dodecanoyl-L-homoserine lactone. P. aeruginosa isolates with lasR mutations are characterized by an iridescent high sheen phenotype caused by a build-up of 2-heptyl-4-quinolone. A previous study demonstrated 22% (n=101) of P. aeruginosa keratitis isolates from India between 2010 and 2016 were sheen positive lasR mutants, and the sheen phenotype correlated with worse clinical outcomes for patients. In this study, a longitudinal collection of P. aeruginosa keratitis isolates from Eastern North America were screened for lasR mutations by the sheen phenotype and sequencing of the lasR gene. Methods Keratitis isolates (n=399) were classified by sheen phenotype. The lasR gene was cloned from a subset of isolates, sequenced, and tested for loss of function or dominant-negative status based on an azocasein protease assay. A retrospective chart review compared outcomes of keratitis patients infected by sheen positive and negative isolates. Results A significant increase in sheen positive isolates was observed between 1993 and 2021. Extracellular protease activity was reduced among the sheen positive isolates and a defined lasR mutant. Cloned lasR alleles from the sheen positive isolates were loss of function or dominant negative and differed in sequence from previously reported ocular lasR mutant alleles. Retrospective analysis of patient information suggested significantly better visual outcomes for patients infected by sheen positive isolates. Discussion These results indicate an increase in lasR mutations among keratitis isolates in the United States and suggest that endemic lasR mutants can cause keratitis.
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Affiliation(s)
- Robert M. Q. Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Sarah Atta
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Nicholas A. Stella
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Chollapadi V. Sundar-Raj
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - John E. Romanowski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Arman S. Grewal
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Hazel Q. Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Sonya M. Mumper
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Deepinder K. Dhaliwal
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Alex Mammen
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Jake D. Callaghan
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Rachel C. Calvario
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Eric G. Romanowski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Regis P. Kowalski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
| | - Michael E. Zegans
- Department of Surgery, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, United States
| | - Vishal Jhanji
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, United States
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Shanks RMQ, Atta S, Stella NA, Sundar-Raj CV, Romanowski JE, Grewel AS, Shanks HQ, Mumper SM, Dhaliwal DK, Mammen A, Callaghan JD, Calvario RC, Romanowski EG, Kowalski RP, Zegans ME, Jhanji V. Rise in frequency of lasR mutant Pseudomonas aeruginosa among keratitis isolates between 1993 and 2021. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.22.554354. [PMID: 37662319 PMCID: PMC10473646 DOI: 10.1101/2023.08.22.554354] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2023]
Abstract
Pseudomonas aeruginosa causes severe vision threatening keratitis. LasR is a transcription factor that regulates virulence associated genes in response to the quorum sensing molecule N-3-oxo-dodecanoyl-L-homoserine lactone. P. aeruginosa isolates with lasR mutations are characterized by an iridescent high sheen phenotype caused by a build-up of 2-heptyl-4-quinolone. A previous study indicated a high proportion (22 out of 101) of P. aeruginosa keratitis isolates from India between 2010 and 2016 were sheen positive and had mutations in the lasR gene, and the sheen phenotype correlated with worse clinical outcomes for patients. In this study, a longitudinal collection of P. aeruginosa keratitis isolates from Eastern North America were screened for lasR mutations by the sheen phenotype and sequencing of the lasR gene. A significant increase in the frequency of isolates with the sheen positive phenotype was observed in isolates between 1993 and 2021. Extracellular protease activity was lower among the sheen positive isolates and a defined lasR mutant. Cloned lasR alleles from the sheen positive isolates were loss of function or dominant negative and differed in sequence from previously reported ocular lasR mutant alleles. Insertion elements were present in a subset of independent isolates and may represent an endemic source from some of the isolates. Retrospective analysis of patient information suggested significantly better visual outcomes for patients with infected by sheen positive isolates. Together, these results indicate an increasing trend towards lasR mutations among keratitis isolates at a tertiary eye care hospital in the United States.
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Affiliation(s)
- Robert M. Q. Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sarah Atta
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Nicholas A. Stella
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Chollapadi V. Sundar-Raj
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - John E. Romanowski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Arman S. Grewel
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Hazel Q. Shanks
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Sonya M. Mumper
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Deepinder K. Dhaliwal
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Alex Mammen
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Jake D. Callaghan
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Rachel C. Calvario
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Eric G. Romanowski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Regis P. Kowalski
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Michael E. Zegans
- Department of Surgery, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
- Department of Microbiology and Immunology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Vishal Jhanji
- Charles T. Campbell Laboratory of Ophthalmic Microbiology, Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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Astley RA, Mursalin MH, Coburn PS, Livingston ET, Nightengale JW, Bagaruka E, Hunt JJ, Callegan MC. Ocular Bacterial Infections: A Ten-Year Survey and Review of Causative Organisms Based on the Oklahoma Experience. Microorganisms 2023; 11:1802. [PMID: 37512974 PMCID: PMC10386592 DOI: 10.3390/microorganisms11071802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Revised: 06/29/2023] [Accepted: 07/10/2023] [Indexed: 07/30/2023] Open
Abstract
Ocular infections can be medical emergencies that result in permanent visual impairment or blindness and loss of quality of life. Bacteria are a major cause of ocular infections. Effective treatment of ocular infections requires knowledge of which bacteria are the likely cause of the infection. This survey of ocular bacterial isolates and review of ocular pathogens is based on a survey of a collection of isolates banked over a ten-year span at the Dean McGee Eye Institute in Oklahoma. These findings illustrate the diversity of bacteria isolated from the eye, ranging from common species to rare and unique species. At all sampled sites, staphylococci were the predominant bacteria isolated. Pseudomonads were the most common Gram-negative bacterial isolate, except in vitreous, where Serratia was the most common Gram-negative bacterial isolate. Here, we discuss the range of ocular infections that these species have been documented to cause and treatment options for these infections. Although a highly diverse spectrum of species has been isolated from the eye, the majority of infections are caused by Gram-positive species, and in most infections, empiric treatments are effective.
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Affiliation(s)
- Roger A Astley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Md Huzzatul Mursalin
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Phillip S Coburn
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Erin T Livingston
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - James W Nightengale
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Eddy Bagaruka
- Department of Biology, Oklahoma Christian University, Edmond, OK 73013, USA
| | - Jonathan J Hunt
- Department of Biology, Oklahoma Christian University, Edmond, OK 73013, USA
| | - Michelle C Callegan
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Microbiology and Immunology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
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Sosne G, Berger EA. Thymosin beta 4: A potential novel adjunct treatment for bacterial keratitis. Int Immunopharmacol 2023; 118:109953. [PMID: 37018981 PMCID: PMC10403815 DOI: 10.1016/j.intimp.2023.109953] [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: 11/27/2022] [Revised: 02/08/2023] [Accepted: 02/10/2023] [Indexed: 04/05/2023]
Abstract
Microbial keratitis is a rapidly progressing, visually debilitating infection of the cornea that can lead to corneal scarring, endophthalmitis, and perforation. Corneal opacification or scarring, a complication of keratitis, is among the leading causes of legal blindness worldwide, second to cataracts.Pseudomonas aeruginosaandStaphylococcus aureusare the two bacteria most commonly associated with this type of infection. Risk factors include patients who are immunocompromised, those who have undergone refractive corneal surgery, and those with prior penetrating keratoplasty, as well as extended wear contact lens users. Current treatment of microbial keratitis primarily addresses the pathogen using antibiotics. Bacterial clearance is of utmost importance yet does not guarantee good visual outcome. Clinicians are often left to rely upon the eye's innate ability to heal itself, as there are limited options beyond antibiotics and corticosteroids for treating patients with corneal infection. Beyond antibiotics, agents in use, such as lubricating ointments, artificial tears, and anti-inflammatory drops, do not fully accommodate clinical needs and have many potential harmful complications. To this end, treatments are needed that both regulate the inflammatory response and promote corneal wound healing to resolve visual disturbances and improve quality of life. Thymosin beta 4 is a small, naturally occurring 43-amino-acid protein that promotes wound healing and reduces corneal inflammation and is currently in Phase 3 human clinical trials for dry eye disease. Our previous work has shown that topical Tβ4 as an adjunct to ciprofloxacin treatment reduces inflammatory mediators and inflammatory cell infiltrates (neutrophils/PMN and macrophages) while enhancing bacterial killing and wound healing pathway activation in an experimental model ofP. aeruginosa-induced keratitis. Adjunctive thymosin beta 4 treatment holds novel therapeutic potential to regulate and, optimally, resolve disease pathogenesis in the cornea and perhaps other infectious and immune-based inflammatory disease. We plan to establish the importance of thymosin beta 4 as a therapeutic agent in conjunction with antibiotics with high impact for immediate clinical development.
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Affiliation(s)
- Gabriel Sosne
- Department of Ophthalmology, Visual & Anatomical Sciences, Kresge Eye Institute, Wayne State University School of Medicine, 4717 St. Antoine, Detroit, MI 48201, USA.
| | - Elizabeth A Berger
- Department of Ophthalmology, Visual & Anatomical Sciences, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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9
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Chuprom J, Sangkanu S, Mitsuwan W, Boonhok R, Mahabusarakam W, Singh LR, Dumkliang E, Jitrangsri K, Paul AK, Surinkaew S, Wilairatana P, Pereira MDL, Rahmatullah M, Wiart C, Oliveira SMR, Nissapatorn V. Anti- Acanthamoeba activity of a semi-synthetic mangostin derivative and its ability in removal of Acanthamoeba triangularis WU19001 on contact lens. PeerJ 2022; 10:e14468. [PMID: 36523474 PMCID: PMC9745913 DOI: 10.7717/peerj.14468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 11/06/2022] [Indexed: 12/13/2022] Open
Abstract
Garcinia mangostana L., also known as the mangosteen tree, is a native medicinal plant in Southeast Asia having a wide variety of pharmacologically active compounds, including xanthonoid mangostin. In this study, we examined the pharmacological activities of the selected semi-synthetic mangostin derivative, namely, amoebicidal activity, encystation inhibition, excystation activity, and removal capacity of adhesive Acanthamoeba from the surface of contact lens (CL). Among the three derivatives, C1 exhibited promising anti-Acanthamoeba activity against Acanthamoeba triangularis WU19001 trophozoites and cysts. SEM images displayed morphological changes in Acanthamoeba trophozoites, including the loss of acanthopodia, pore formation in the cell membrane, and membrane damage. In addition, the treated cyst was shrunken and adopted an irregular flat cyst shape. Under a fluorescence microscope, acridine orange and propidium iodide (AO/PI) staining revealed C1 induced condensation of cytoplasm and chromatin with the loss of cell volume in the treated trophozoites, while calcofluor white staining demonstrated the leakage of cell wall in treated cysts, leading to cell death. Interestingly, at the concentration ranges in which C1 showed the anti-Acanthamoeba effects (IC50 values ranging from 0.035-0.056 mg/mL), they were not toxic to Vero cells. C1 displayed the highest inhibitory effect on A. triangularis encystation at 1/16×MIC value (0.004 mg/mL). While C1 demonstrated the excystation activity at 1/128×MIC value with a high rate of 89.47%. Furthermore, C1 exhibited the removal capacity of adhesive Acanthamoeba from the surface of CL comparable with commercial multipurpose solutions (MPSs). Based on the results obtained, C1 may be a promising lead agent to develop a therapeutic for the treatment of Acanthamoeba infections and disinfectant solutions for CL.
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Affiliation(s)
- Julalak Chuprom
- School of Allied Health Sciences, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat, Thailand,School of Languages and General Education (SOLGEN), Walailak University, Nakhon Si Thammarat, Thailand
| | - Suthinee Sangkanu
- School of Allied Health Sciences, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat, Thailand
| | - Watcharapong Mitsuwan
- Akkhraratchakumari Veterinary College, Walailak University, Nakhon Si Thammarat, Thailand
| | - Rachasak Boonhok
- Department of Medical Technology, School of Allied Health Sciences, Research Excellence Center for Innovation and Health Products (RECIHP), Walailak University, Nakhon Si Thammarat, Thailand
| | - Wilawan Mahabusarakam
- Division of Physical Science, Faculty of Science, Prince of Songkla University, Songkhla, Thailand
| | - L. Ravithej Singh
- Fluoro-Agrochemicals Division, CSIR–Indian Institute of Chemical Technology, Tarnaka, Hyderabad, India,Chemical Sciences Division, Academy of Scientific and Innovative Research, Ghaziabad, India
| | - Ekachai Dumkliang
- Faculty of Pharmacy, Silpakorn University, Pharmaceutical Development of Green Innovations Group (PDGIG), Nakhon Pathom, Thailand
| | - Kritamorn Jitrangsri
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, Thailand
| | - Alok K. Paul
- School of Pharmacy and Pharmacology, University of Tasmania, Hobart, Australia
| | - Sirirat Surinkaew
- Department of Medical Technology, School of Allied Health Sciences, Walailak University, Nakhon Si Thammarat, Thailand
| | - Polrat Wilairatana
- Department of Clinical Tropical Medicine, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Maria de Lourdes Pereira
- CICECO-Aveiro Institute of Materials & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal,Department of Medical Sciences, University of Aveiro, Aveiro, Portugal
| | - Mohammed Rahmatullah
- Department of Biotechnology & Genetic Engineering, University of Development Alternative, Lalmatia, Dhaka, Bangladesh
| | - Christophe Wiart
- The Institute for Tropical Biology and Conservation, University Malaysia Sabah, Kota Kin-abalu, Sabah, Malaysia
| | - Sonia Marlene Rodrigues Oliveira
- CICECO-Aveiro Institute of Materials & Department of Medical Sciences, University of Aveiro, Aveiro, Portugal,Hunter Medical Research Institute, New Lambton, Australia
| | - Veeranoot Nissapatorn
- School of Allied Health Sciences, Southeast Asia Water Team (SEA Water Team) and World Union for Herbal Drug Discovery (WUHeDD), Walailak University, Nakhon Si Thammarat, Thailand
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10
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Genetic Identification of Pseudomonas aeruginosa Virulence Genes Associated with Keratitis in Egyptian Population. JOURNAL OF PURE AND APPLIED MICROBIOLOGY 2022. [DOI: 10.22207/jpam.16.3.12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Infectious keratitis continues to be a prominent cause of vision impairment worldwide through a variety of causes. Pseudomonas aeruginosa is a Gram-negative bacterium that frequently causes vision-threatening microbial keratitis. P. aeruginosa contains a diverse array of virulence factors, including exoA, exoS, nan1, and lasB, some of which may contribute to its pathogenicity. Because the clinical characteristics of bacterial keratitis vary, making a quick differential diagnosis can be difficult, resulting in a delay in diagnosis and worse outcome. In this study, we performed multiplex polymerase chain reaction to detect the presence of nan1, toxA, exoS, and lasB, and determine their association with distinct clinical presentations of P. aeruginosa-related keratitis. We also performed antibiotic susceptibility testing of the isolates. A total of 49 P. aeruginosa strains were obtained from individuals with keratitis between May 2021 and December 2021 from the Research Institute of Ophthalmology, Giza, Egypt. Results showed that lasB was most expressed gene (81.8%), followed by tox (63.6%) and exoS (31.8%), whereas nan1 was the least commonly expressed gene 1316 (22.7%). The antibiotic susceptibility profile showed that TOB was the least sensitive antibiotic (26.5%), followed by CIP (34.7%), whereas CT was the most sensitive antibiotic (89.8%), followed by GAT (83.7%) and PB (81.6%). Several virulence genes were identified in P. aeruginosa isolates, suggesting that these genes are associated with varying degrees of intrinsic virulence and pathogenicity. Substantial associations between specific virulence genes and the source of infection imply that infection control measures can aid in regulating the distribution of virulence genes among P. aeruginosa strains.
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11
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Liao C, Huang X, Wang Q, Yao D, Lu W. Virulence Factors of Pseudomonas Aeruginosa and Antivirulence Strategies to Combat Its Drug Resistance. Front Cell Infect Microbiol 2022; 12:926758. [PMID: 35873152 PMCID: PMC9299443 DOI: 10.3389/fcimb.2022.926758] [Citation(s) in RCA: 86] [Impact Index Per Article: 43.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2022] [Accepted: 06/09/2022] [Indexed: 11/24/2022] Open
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen causing nosocomial infections in severely ill and immunocompromised patients. Ubiquitously disseminated in the environment, especially in hospitals, it has become a major threat to human health due to the constant emergence of drug-resistant strains. Multiple resistance mechanisms are exploited by P. aeruginosa, which usually result in chronic infections difficult to eradicate. Diverse virulence factors responsible for bacterial adhesion and colonization, host immune suppression, and immune escape, play important roles in the pathogenic process of P. aeruginosa. As such, antivirulence treatment that aims at reducing virulence while sparing the bacterium for its eventual elimination by the immune system, or combination therapies, has significant advantages over traditional antibiotic therapy, as the former imposes minimal selective pressure on P. aeruginosa, thus less likely to induce drug resistance. In this review, we will discuss the virulence factors of P. aeruginosa, their pathogenic roles, and recent advances in antivirulence drug discovery for the treatment of P. aeruginosa infections.
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Affiliation(s)
- Chongbing Liao
- Key Laboratory of Medical Molecular Virology (Ministry of Education (MOE)/National Health Commission (NHC)/Chinese Academy of Medical Sciences (CAMS)), School of Basic Medical Science, Fudan University, Shanghai, China
| | - Xin Huang
- Key Laboratory of Medical Molecular Virology (Ministry of Education (MOE)/National Health Commission (NHC)/Chinese Academy of Medical Sciences (CAMS)), School of Basic Medical Science, Fudan University, Shanghai, China
| | - Qingxia Wang
- Key Laboratory of Medical Molecular Virology (Ministry of Education (MOE)/National Health Commission (NHC)/Chinese Academy of Medical Sciences (CAMS)), School of Basic Medical Science, Fudan University, Shanghai, China
| | - Dan Yao
- Key Laboratory of Medical Molecular Virology (Ministry of Education (MOE)/National Health Commission (NHC)/Chinese Academy of Medical Sciences (CAMS)), School of Basic Medical Science, Fudan University, Shanghai, China
| | - Wuyuan Lu
- Key Laboratory of Medical Molecular Virology (Ministry of Education (MOE)/National Health Commission (NHC)/Chinese Academy of Medical Sciences (CAMS)), School of Basic Medical Science, Fudan University, Shanghai, China
- Shanghai Institute of Infectious Disease and Biosecurity, School of Public Health, Fudan University, Shanghai, China
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12
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Chen D, Song D, Ma Y, Lu W, Qiu J, Wang Y. USP22 promotes pro‑inflammatory responses in Pseudomonas aeruginosa‑induced keratitis by targeting TRAF6. Mol Med Rep 2022; 25:149. [PMID: 35244191 DOI: 10.3892/mmr.2022.12665] [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: 06/26/2019] [Accepted: 11/11/2020] [Indexed: 11/06/2022] Open
Abstract
Pseudomonas aeruginosa (PA)‑induced keratitis is characterized by inflammatory epithelial edema, stromal infiltration, corneal ulceration and can lead to vision loss. The present study aimed to study the effect of ubiquitin‑specific protease 22 (USP22) on PA‑induced keratitis. Using RT‑qPCR and western blotting, significantly increased expression of USP22 was identified in mouse corneas and cultured RAW264.7 cells following PA stimulation. In addition, the results of in vivo experiments, western blot assay and ELISA suggested that the silencing of USP22 attenuated disease progression, downregulated the NF‑κB pathway and suppressed the expression of pro‑inflammatory cytokines following PA stimulation. Notably, it was identified that the expression of tumor necrosis factor receptor‑associated factor 6 (TRAF6) was decreased by silencing of USP22 and USP22 was found to remove lysine 48‑linked poly‑ubiquitination chains from TRAF6 to stabilize TRAF6 expression and these effects were clearly aggravated following PA infection.
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Affiliation(s)
- Di Chen
- Department of Ophthalmology, Second Affiliated Hospital of Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong 271000, P.R. China
| | - Dawei Song
- Department of Ophthalmology, Tai'an City Central Hospital, Tai'an, Shandong 271000, P.R. China
| | - Yibin Ma
- Department of Ophthalmology, Tai'an City Central Hospital, Tai'an, Shandong 271000, P.R. China
| | - Weizhao Lu
- Department of Radiology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong 271000, P.R. China
| | - Jianfeng Qiu
- Department of Radiology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong 271000, P.R. China
| | - Yi Wang
- Department of Ophthalmology, Shandong First Medical University and Shandong Academy of Medical Sciences, Tai'an, Shandong 271000, P.R. China
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13
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Adsorption of extracellular proteases and pyocyanin produced by Pseudomonas aeruginosa using a macroporous magnesium oxide-templated carbon decreases cytotoxicity. CURRENT RESEARCH IN MICROBIAL SCIENCES 2022; 3:100160. [DOI: 10.1016/j.crmicr.2022.100160] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 08/17/2022] [Accepted: 08/17/2022] [Indexed: 11/17/2022] Open
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14
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Siddiqui R, Shah RA, Akbar N, Khamis M, Ibrahim T, Abouleish MY, Khan NA. Antibacterial effects of octadecyl trimethylammonium micelle-clay complex against bacterial eye pathogens: potential as a contact lens disinfectant. Int Ophthalmol 2021; 42:939-944. [PMID: 34611769 DOI: 10.1007/s10792-021-02075-7] [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: 08/08/2021] [Accepted: 09/24/2021] [Indexed: 10/20/2022]
Abstract
AIM In this study, we utilized a micelle-clay complex composed of the surfactant octadecyltrimethylammonium bromide and montmorillonite clay and evaluated its antibacterial effects. METHODS Using Pseudomonas aeruginosa, Staphylococcus epidermidis, and Micrococcus luteus, bactericidal assays were performed to determine the effects of ODTMA-clay complex on the viability of bacterial pathogen at various doses and different intervals of time. Cytotoxicity assays were performed to investigate ODTMA-clay complex effects on human cells, as determined by release of intracellular lactate dehydrogenase. RESULTS The results revealed that ODTMA-clay complex abolished bacterial viability at 100 μg/mL within 45 min against P. aeruginosa, S. epidermidis, and M. luteus. Cytotoxicity assays revealed that ODTMA-clay complex exhibited minimal toxicity of the human cells. CONCLUSION Rapid and potent antibacterial effects of ODTMA micelle-clay complex were observed in vitro; however, research is needed to determine precise formulation of contact lens disinfectants comprising ODTMA micelle-clay complex. Additionally, studies should be conducted using in vivo models of keratitis, progressing to pre-clinical and clinical trials. ODTMA micelle-clay complex is an ideal candidate to be incorporated in a novel contact lens disinfectant given the cost-effectiveness and ease of application and can be incorporated as an effective preventative strategy.
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Affiliation(s)
- Ruqaiyyah Siddiqui
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Rida Arshad Shah
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Noor Akbar
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Mustafa Khamis
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Taleb Ibrahim
- Department of Chemical Engineering, College of Engineering, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Mohamed Yehia Abouleish
- College of Arts and Sciences, American University of Sharjah, University City, Sharjah, United Arab Emirates
| | - Naveed Ahmed Khan
- Department of Clinical Sciences, College of Medicine, University of Sharjah, PO Box 27272, University City, Sharjah, United Arab Emirates.
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15
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Chadha J, Harjai K, Chhibber S. Revisiting the virulence hallmarks of Pseudomonas aeruginosa: a chronicle through the perspective of quorum sensing. Environ Microbiol 2021; 24:2630-2656. [PMID: 34559444 DOI: 10.1111/1462-2920.15784] [Citation(s) in RCA: 69] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 09/16/2021] [Accepted: 09/17/2021] [Indexed: 12/15/2022]
Abstract
Pseudomonas aeruginosa is an opportunistic pathogen and the leading cause of mortality among immunocompromised patients in clinical setups. The hallmarks of virulence in P. aeruginosa encompass six biologically competent attributes that cumulatively drive disease progression in a multistep manner. These multifaceted hallmarks lay the principal foundation for rationalizing the complexities of pseudomonal infections. They include factors for host colonization and bacterial motility, biofilm formation, production of destructive enzymes, toxic secondary metabolites, iron-chelating siderophores and toxins. This arsenal of virulence hallmarks is fostered and stringently regulated by the bacterial signalling system called quorum sensing (QS). The central regulatory functions of QS in controlling the timely expression of these virulence hallmarks for adaptation and survival drive the disease outcome. This review describes the intricate mechanisms of QS in P. aeruginosa and its role in shaping bacterial responses, boosting bacterial fitness. We summarize the virulence hallmarks of P. aeruginosa, relating them with the QS circuitry in clinical infections. We also examine the role of QS in the development of drug resistance and propose a novel antivirulence therapy to combat P. aeruginosa infections. This can prove to be a next-generation therapy that may eventually become refractory to the use of conventional antimicrobial treatments.
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Affiliation(s)
- Jatin Chadha
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Kusum Harjai
- Department of Microbiology, Panjab University, Chandigarh, India
| | - Sanjay Chhibber
- Department of Microbiology, Panjab University, Chandigarh, India
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16
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Nishida T, Sugioka K, Fukuda K, Murakami J. Pivotal Role of Corneal Fibroblasts in Progression to Corneal Ulcer in Bacterial Keratitis. Int J Mol Sci 2021; 22:ijms22168979. [PMID: 34445684 PMCID: PMC8396668 DOI: 10.3390/ijms22168979] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 08/12/2021] [Accepted: 08/17/2021] [Indexed: 01/05/2023] Open
Abstract
The shape and transparency of the cornea are essential for clear vision. However, its location at the ocular surface renders the cornea vulnerable to pathogenic microorganisms in the external environment. Pseudomonas aeruginosa and Staphylococcus aureus are two such microorganisms and are responsible for most cases of bacterial keratitis. The development of antimicrobial agents has allowed the successful treatment of bacterial keratitis if the infection is diagnosed promptly. However, no effective medical treatment is available after progression to corneal ulcer, which is characterized by excessive degradation of collagen in the corneal stroma and can lead to corneal perforation and corneal blindness. This collagen degradation is mediated by both infecting bacteria and corneal fibroblasts themselves, with a urokinase-type plasminogen activator (uPA)-plasmin-matrix metalloproteinase (MMP) cascade playing a central role in collagen destruction by the host cells. Bacterial factors stimulate the production by corneal fibroblasts of both uPA and pro-MMPs, released uPA mediates the conversion of plasminogen in the extracellular environment to plasmin, and plasmin mediates the conversion of secreted pro-MMPs to the active form of these enzymes, which then degrade stromal collagen. Bacterial factors also stimulate expression by corneal fibroblasts of the chemokine interleukin-8 and the adhesion molecule ICAM-1, both of which contribute to recruitment and activation of polymorphonuclear neutrophils, and these cells then further stimulate corneal fibroblasts via the secretion of interleukin-1. At this stage of the disease, bacteria are no longer necessary for collagen degradation. In this review, we discuss the pivotal role of corneal fibroblasts in corneal ulcer associated with infection by P. aeruginosa or S. aureus as well as the development of potential new modes of treatment for this condition.
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Affiliation(s)
- Teruo Nishida
- Department of Ophthalmology, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi 755-8505, Japan;
- Division of Cornea and Ocular Surface, Ohshima Eye Hospital, Fukuoka 812-0036, Japan
| | - Koji Sugioka
- Department of Ophthalmology, Kindai University Nara Hospital, Ikoma, Nara 630-0293, Japan;
| | - Ken Fukuda
- Department of Ophthalmology and Visual Science, Kochi Medical School, Kochi University, Nankoku, Kochi 783-8505, Japan
- Correspondence:
| | - Junko Murakami
- Division of Ophthalmology, Sakibana Hospital, Izumi, Osaka 594-1105, Japan;
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17
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Hammers D, Carothers K, Lee S. The Role of Bacterial Proteases in Microbe and Host-microbe Interactions. Curr Drug Targets 2021; 23:222-239. [PMID: 34370632 DOI: 10.2174/1389450122666210809094100] [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: 03/11/2021] [Revised: 06/15/2021] [Accepted: 06/16/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Secreted proteases are an important class of factors used by bacterial to modulate their extracellular environment through the cleavage of peptides and proteins. These proteases can range from broad, general proteolytic activity to high degrees of substrate specificity. They are often involved in interactions between bacteria and other species, even across kingdoms, allowing bacteria to survive and compete within their niche. As a result, many bacterial proteases are of clinical importance. The immune system is a common target for these enzymes, and bacteria have evolved ways to use these proteases to alter immune responses for their benefit. In addition to the wide variety of human proteins that can be targeted by bacterial proteases, bacteria also use these secreted factors to disrupt competing microbes, ranging from outright antimicrobial activity to disrupting processes like biofilm formation. OBJECTIVE In this review, we address how bacterial proteases modulate host mechanisms of protection from infection and injury, including immune factors and cell barriers. We also discuss the contributions of bacterial proteases to microbe-microbe interactions, including antimicrobial and anti-biofilm dynamics. CONCLUSION Bacterial secreted proteases represent an incredibly diverse group of factors that bacteria use to shape and thrive in their microenvironment. Due to the range of activities and targets of these proteases, some have been noted for having potential as therapeutics. The vast array of bacterial proteases and their targets remains an expanding field of research, and this field has many important implications for human health.
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Affiliation(s)
- Daniel Hammers
- Department of Biological Sciences, University of Notre Dame, Galvin Hall, Notre Dame, IN 46556, United States
| | - Katelyn Carothers
- Department of Biological Sciences, University of Notre Dame, Galvin Hall, Notre Dame, IN 46556, United States
| | - Shaun Lee
- Department of Biological Sciences, University of Notre Dame, Galvin Hall, Notre Dame, IN 46556, United States
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18
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Donovan C, Koudouna E, Margo CE, Avila MY, Espana EM. Genipin Delays Corneal Stromal Enzymatic Digestion. Transl Vis Sci Technol 2021; 10:25. [PMID: 34424287 PMCID: PMC8394563 DOI: 10.1167/tvst.10.9.25] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose To evaluate the use of genipin in delaying enzymatic digestion of corneal stroma. Methods Human corneal stromal tissue was treated with genipin, a known chemical crosslinker, and then along with control tissue was subjected to enzymatic digestion with collagenase. The effects of genipin treatment in retarding stromal digestion were analyzed with phase contrast microscopy, a protein quantification assay, second harmonic generation imaging, and transmission electron microscopy. Results Genipin increased stromal resistance to enzymatic digestion when compared with untreated stroma. A morphologic analysis and protein quantification showed increased stromal resistance to enzymatic digestion once stromal tissue was treated with genipin. Second harmonic generation imaging revealed persistent fibrillar collagen signaling in genipin-treated tissue in contrast with untreated tissue suggesting that genipin retards collagenolysis. Conclusions Genipin increases stromal resistance to enzymatic digestion in controlled experiments as demonstrated by protein quantification studies and through morphologic imaging. Translational Relevance This study explores the novel use of genipin in delaying enzymatic stromal digestion. Delaying stromal melting in the setting of corneal infectious or autoimmune keratitis can potentially decrease clinical morbidity.
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Affiliation(s)
- Christopher Donovan
- Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Elena Koudouna
- Department of Ophthalmology, School of Medicine, Universidad Nacional de Colombia, Hospital Universitario Nacional, Bogota, Colombia.,Structural Biophysics Group, School of Optometry and Vision Sciences, Cardiff University, Cardiff, UK
| | - Curtis E Margo
- Department of Pathology and Cell Biology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
| | - Marcel Y Avila
- Department of Ophthalmology, School of Medicine, Universidad Nacional de Colombia, Hospital Universitario Nacional, Bogota, Colombia
| | - Edgar M Espana
- Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA.,Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, Tampa, FL, USA
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19
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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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20
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Zakirova GZ, Samoylov AN, Rascheskov AY. [Keratitis associated with contact lens correction in children and adolescents]. Vestn Oftalmol 2021; 137:21-25. [PMID: 34156774 DOI: 10.17116/oftalma202113703121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Currently, the number of contact lens users in the world is approximately 10% of the total population of developed countries. Despite the undeniable advantages of contact lenses over eyeglasses, complications are an unpleasant aspect of their use. An analysis of the literature showed that purulent-inflammatory complications have not been fully described. PURPOSE To study the prevalence of keratitis associated with contact lenses, its clinical manifestations, microbial etiology, and sensitivity to antibiotics. MATERIAL AND METHODS The study analyzes case histories of 171 patients with infectious keratitis treated at the Children's Republican Clinical Hospital of the Ministry of Health of the Republic of Tatarstan in 2016-2018. RESULTS The retrospective analysis revealed an increase in both the number of infectious keratitis and the keratitis associated with contact correction. All patients had a severe course of keratitis with the formation of gross opacity. The leading pathogens were Pseudomonas aeruginosae and Klebsiella oxytoca. The pathogens were not 100% sensitive to any one of the 7 studied antibiotics. The smallest percentage of resistant strains (12.5%) was determined for fluoroquinolones of the 2nd and 3rd generation (ciprofloxacin and levofloxacin), as well as meropenem. CONCLUSION Considering the number of contact lens users in the world, keratitis associated with contact lenses poses a serious problem.
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Affiliation(s)
- G Z Zakirova
- Kazan State Medical University, Kazan, Russia.,Children's Clinical Hospital of the Ministry of Health of the Republic of Tatarstan, Kazan, Russia
| | | | - A Yu Rascheskov
- Children's Clinical Hospital of the Ministry of Health of the Republic of Tatarstan, Kazan, Russia
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21
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Axelrad I, Safrin M, Cahan R, Suh SJ, Ohman DE, Kessler E. Extracellular proteolytic activation of Pseudomonas aeruginosa aminopeptidase (PaAP) and insight into the role of its non-catalytic N-terminal domain. PLoS One 2021; 16:e0252970. [PMID: 34133429 PMCID: PMC8208579 DOI: 10.1371/journal.pone.0252970] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2021] [Accepted: 05/25/2021] [Indexed: 11/18/2022] Open
Abstract
Pseudomonas aeruginosa secretes several endopeptidases, including elastase, alkaline proteinase (Apr), a lysine-specific endopeptidase (LysC), and an aminopeptidase (PaAP), all of which are important virulence factors. Activation of the endopeptidases requires removal of an inhibitory N-terminal propeptide. Activation of pro-PaAP, in contrast, requires C-terminal processing. The activating proteases of pro-PaAP and their cleavage site(s) have not yet been defined. Studying pro-PaAP processing in a wild type P. aeruginosa strain and strains lacking either elastase or both elastase and Apr, we detected three processing variants, each ~56 kDa in size (AP56). Activity assays and N- and C-terminal sequence analyses of these variants pointed at LysC as the principal activating protease, cleaving a Lys512-Ala513 peptide bond at the C-terminal end of pro-PaAP. Elastase and/or Apr are required for activation of LysC, suggesting both are indirectly involved in activation of PaAP. To shed light on the function(s) of the N-terminal domain of AP56, we purified recombinant AP56 and generated from it the 28 kDa catalytic domain (AP28). The kinetic constants (Km and Kcat) for hydrolysis of Leu-, Lys-, Arg- and Met-p-nitroanilide (pNA) derivatives by AP56 and AP28 were then determined. The catalytic coefficients (Kcat/Km) for hydrolysis of all four substrates by AP28 and AP56 were comparable, indicating that the non-catalytic domain is not involved in hydrolysis of small substrates. It may, however, regulate hydrolysis of natural peptides/proteins. Lys-pNA was hydrolyzed 2 to 3-fold more rapidly than Leu-pNA and ~8-fold faster than Arg- or Met-pNA, indicating that Lys-pNA was the preferred substrate.
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Affiliation(s)
- Itschak Axelrad
- Maurice and Gabriela Goldschleger Eye Research Institute, Tel Aviv University Sackler Faculty of Medicine, Sheba Medical Center, Tel-Hashomer, Ramat Gan, Israel
| | - Mary Safrin
- Maurice and Gabriela Goldschleger Eye Research Institute, Tel Aviv University Sackler Faculty of Medicine, Sheba Medical Center, Tel-Hashomer, Ramat Gan, Israel
| | - Rivka Cahan
- Maurice and Gabriela Goldschleger Eye Research Institute, Tel Aviv University Sackler Faculty of Medicine, Sheba Medical Center, Tel-Hashomer, Ramat Gan, Israel
| | - Sang-Jin Suh
- Department of Biomedical Sciences, Texas A&M College of Dentistry, Dallas, Texas, United States of America
| | - Dennis E. Ohman
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, Virginia, United States of America
- McGuire Veterans Affairs Medical Center, Richmond, Virginia, United States of America
| | - Efrat Kessler
- Maurice and Gabriela Goldschleger Eye Research Institute, Tel Aviv University Sackler Faculty of Medicine, Sheba Medical Center, Tel-Hashomer, Ramat Gan, Israel
- * E-mail:
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22
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Antimicrobial nanomedicine for ocular bacterial and fungal infection. Drug Deliv Transl Res 2021; 11:1352-1375. [PMID: 33840082 DOI: 10.1007/s13346-021-00966-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/17/2021] [Indexed: 12/13/2022]
Abstract
Ocular infection induced by bacteria and fungi is a major cause of visual impairment and blindness. Topical administration of antibiotics remains the first-line treatment, as effective eradication of pathogens is the core of the anti-infection strategy. Whereas, eye drops lack efficiency and have relatively low bioavailability. Intraocular injection may cause concurrent ocular damage and secondary infection. In addition, antibiotic-based management can be limited by the low sensitivity to multidrug-resistant bacteria. Nanomedicine is proposed as a prospective, effective, and noninvasive platform to mediate ocular delivery and combat pathogen or even resistant strains. Nanomedicine can not only carry antimicrobial agents to fight against pathogens but also directly active microbicidal capability, killing pathogens. More importantly, by modification, nanomedicine can achieve enhanced residence time and release time on the cornea, and easy penetration through corneal tissues into anterior and posterior segments of the eye, thus improving the therapeutic effect for ocular infection. In this review, several categories of antimicrobial nanomedicine are systematically discussed, where the efficiency and possibility of further embellishment and improvement to adapt to clinical use are also investigated. All in all, novel antimicrobial nanomedicine provides potent and prospective ways to manage severe and refractory ocular infections.
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23
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Tsvetanova A, Powell RM, Tsvetanov KA, Smith KM, Gould DJ. Melting corneal ulcers (keratomalacia) in dogs: A 5-year clinical and microbiological study (2014-2018). Vet Ophthalmol 2021; 24:265-278. [PMID: 33794048 DOI: 10.1111/vop.12885] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2020] [Revised: 03/15/2021] [Accepted: 03/15/2021] [Indexed: 01/26/2023]
Abstract
OBJECTIVES To identify bacterial microorganisms associated with canine keratomalacia, review their antimicrobial sensitivity, and evaluate clinical outcomes compared to results of microbial culture. METHODS Retrospective analysis of clinical records of dogs diagnosed with a melting corneal ulcer presented to a referral hospital in Hertfordshire, UK between 2014 and 2018. RESULTS One hundred and ten melting corneal ulcers were sampled in 106 dogs. The most common pure bacterial isolate was Pseudomonas aeruginosa (n = 26) followed by β-hemolytic Streptococcus (n = 12). Melting corneal ulcers that cultured coagulase-positive Staphylococcus, coliform bacteria, Pasteurella multocida, Enterococcus, and Streptococcus viridans presented in smaller numbers and were analyzed together (n = 16). Multiple cultures were identified in nine cases (n = 9). Forty-seven cultures yielded no bacterial growth (n = 47). The susceptibility to fluoroquinolones remained high with the exception of β-hemolytic Streptococci. There was no significant difference in the ulcer severity at presentation in regard to the cultured bacteria. Overall, 63 eyes (57%) received surgical grafting in addition to medical treatment. In 14 cases (13%), the progression of corneal melting despite medical ± surgical treatment resulted in enucleation. Fifty-seven percent (8/14) of the enucleated eyes cultured pure Pseudomonas aeruginosa isolates. In contrast, all β-hemolytic Streptococcus-associated ulcers healed. CONCLUSIONS The most common bacterial species associated with canine keratomalacia were Pseudomonas aeruginosa and β-hemolytic Streptococcus. Because of the variation in antibacterial sensitivity between these two species, bacterial culture and sensitivity testing should be performed in all dogs presenting with keratomalacia. Melting corneal ulcers associated with pure Pseudomonas infection were significantly more likely to result in globe loss than melting corneal ulcers associated with other cultures.
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Affiliation(s)
- Agata Tsvetanova
- Davies Veterinary Specialists, Manor Farm Business Park, Hertfordshire, UK
| | | | - Kamen A Tsvetanov
- Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK
| | - Kerry M Smith
- Davies Veterinary Specialists, Manor Farm Business Park, Hertfordshire, UK
| | - David J Gould
- Davies Veterinary Specialists, Manor Farm Business Park, Hertfordshire, UK
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Kandasamy K, Thirumalmuthu K, Prajna NV, Lalitha P, Mohankumar V, Devarajan B. Comparative genomics of ocular Pseudomonas aeruginosa strains from keratitis patients with different clinical outcomes. Genomics 2020; 112:4769-4776. [DOI: 10.1016/j.ygeno.2020.08.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 08/19/2020] [Accepted: 08/27/2020] [Indexed: 12/21/2022]
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Sauvage S, Hardouin J. Exoproteomics for Better Understanding Pseudomonas aeruginosa Virulence. Toxins (Basel) 2020; 12:E571. [PMID: 32899849 PMCID: PMC7551764 DOI: 10.3390/toxins12090571] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/25/2020] [Accepted: 09/01/2020] [Indexed: 12/12/2022] Open
Abstract
Pseudomonas aeruginosa is the most common human opportunistic pathogen associated with nosocomial diseases. In 2017, the World Health Organization has classified P. aeruginosa as a critical agent threatening human health, and for which the development of new treatments is urgently necessary. One interesting avenue is to target virulence factors to understand P. aeruginosa pathogenicity. Thus, characterising exoproteins of P. aeruginosa is a hot research topic and proteomics is a powerful approach that provides important information to gain insights on bacterial virulence. The aim of this review is to focus on the contribution of proteomics to the studies of P. aeruginosa exoproteins, highlighting its relevance in the discovery of virulence factors, post-translational modifications on exoproteins and host-pathogen relationships.
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Affiliation(s)
- Salomé Sauvage
- Polymers, Biopolymers, Surface Laboratory, UMR 6270 CNRS, University of Rouen, CEDEX, F-76821 Mont-Saint-Aignan, France;
- PISSARO Proteomics Facility, IRIB, F-76820 Mont-Saint-Aignan, France
| | - Julie Hardouin
- Polymers, Biopolymers, Surface Laboratory, UMR 6270 CNRS, University of Rouen, CEDEX, F-76821 Mont-Saint-Aignan, France;
- PISSARO Proteomics Facility, IRIB, F-76820 Mont-Saint-Aignan, France
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Xylose-Inducible Promoter Tools for Pseudomonas Species and Their Use in Implicating a Role for the Type II Secretion System Protein XcpQ in the Inhibition of Corneal Epithelial Wound Closure. Appl Environ Microbiol 2020; 86:AEM.00250-20. [PMID: 32414795 DOI: 10.1128/aem.00250-20] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 05/08/2020] [Indexed: 12/17/2022] Open
Abstract
Tunable control of gene expression is an invaluable tool for biological experiments. In this study, we describe a new xylose-inducible promoter system and evaluate it in both Pseudomonas aeruginosa and Pseudomonas fluorescens The Pxut promoter, derived from the P. fluorescens xut operon, was incorporated into a broad-host-range pBBR1-based plasmid and was compared to the Escherichia coli-derived PBAD promoter using gfp as a reporter. Green fluorescent protein (GFP) fluorescence from the Pxut promoter was inducible in both Pseudomonas species, but not in E. coli, which may facilitate the cloning of genes toxic to E. coli to generate plasmids. The Pxut promoter was activated at a lower inducer concentration than PBAD in P. fluorescens, and higher gfp levels were achieved using Pxut Flow cytometry analysis indicated that Pxut was leakier than PBAD in the Pseudomonas species tested but was expressed in a higher proportion of cells when induced. d-Xylose as a sole carbon source did not support the growth of P. aeruginosa or P. fluorescens and is less expensive than many other commonly used inducers, which could facilitate large-scale applications. The efficacy of this system was demonstrated by its use to reveal a role for the P. aeruginosa type II secretion system gene xcpQ in bacterial inhibition of corneal epithelial cell wound closure. This study introduces a new inducible promoter system for gene expression for use in Pseudomonas species.IMPORTANCE Pseudomonas species are enormously important in human infections, in biotechnology, and as model systems for investigating basic science questions. In this study, we have developed a xylose-inducible promoter system, evaluated it in P. aeruginosa and P. fluorescens, and found it to be suitable for the strong induction of gene expression. Furthermore, we have demonstrated its efficacy in controlled gene expression to show that a type II secretion system protein from P. aeruginosa, XcpQ, is important for host-pathogen interactions in a corneal wound closure model.
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