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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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Chatterjee R, Chowdhury AR, Mukherjee D, Chakravortty D. Lipid larceny: channelizing host lipids for establishing successful pathogenesis by bacteria. Virulence 2021; 12:195-216. [PMID: 33356849 PMCID: PMC7808437 DOI: 10.1080/21505594.2020.1869441] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Revised: 12/03/2020] [Accepted: 12/17/2020] [Indexed: 12/16/2022] Open
Abstract
Lipids are complex organic compounds made up of carbon, oxygen, and hydrogen. These play a diverse and intricate role in cellular processes like membrane trafficking, protein sorting, signal transduction, and bacterial infections. Both Gram-positive bacteria (Staphylococcus sp., Listeria monocytogenes, etc.) and Gram-negative bacteria (Chlamydia sp., Salmonella sp., E. coli, etc.) can hijack the various host-lipids and utilize them structurally as well as functionally to mount a successful infection. The pathogens can deploy with various arsenals to exploit host membrane lipids and lipid-associated receptors as an attachment for toxins' landing or facilitate their entry into the host cellular niche. Bacterial species like Mycobacterium sp. can also modulate the host lipid metabolism to fetch its carbon source from the host. The sequential conversion of host membrane lipids into arachidonic acid and prostaglandin E2 due to increased activity of cPLA-2 and COX-2 upon bacterial infection creates immunosuppressive conditions and facilitates the intracellular growth and proliferation of bacteria. However, lipids' more debatable role is that they can also be a blessing in disguise. Certain host-lipids, especially sphingolipids, have been shown to play a crucial antibacterial role and help the host in combating the infections. This review shed light on the detailed role of host lipids in bacterial infections and the current understanding of the lipid in therapeutics. We have also discussed potential prospects and the need of the hour to help us cope in this race against deadly pathogens and their rapidly evolving stealthy virulence strategies.
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Affiliation(s)
- Ritika Chatterjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Atish Roy Chowdhury
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Debapriya Mukherjee
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Division of Biological Sciences, Indian Institute of Science, Bangalore, India
- Centre for Biosystems Science and Engineering, Indian Institute of Science, Bangalore, India
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3
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Singh RB, Das S, Chodosh J, Sharma N, Zegans ME, Kowalski RP, Jhanji V. Paradox of complex diversity: Challenges in the diagnosis and management of bacterial keratitis. Prog Retin Eye Res 2021; 88:101028. [PMID: 34813978 DOI: 10.1016/j.preteyeres.2021.101028] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 11/09/2021] [Accepted: 11/12/2021] [Indexed: 12/12/2022]
Abstract
Bacterial keratitis continues to be one of the leading causes of corneal blindness in the developed as well as the developing world, despite swift progress since the dawn of the "anti-biotic era". Although, we are expeditiously developing our understanding about the different causative organisms and associated pathology leading to keratitis, extensive gaps in knowledge continue to dampen the efforts for early and accurate diagnosis, and management in these patients, resulting in poor clinical outcomes. The ability of the causative bacteria to subdue the therapeutic challenge stems from their large genome encoding complex regulatory networks, variety of unique virulence factors, and rapid secretion of tissue damaging proteases and toxins. In this review article, we have provided an overview of the established classical diagnostic techniques and therapeutics for keratitis caused by various bacteria. We have extensively reported our recent in-roads through novel tools for accurate diagnosis of mono- and poly-bacterial corneal infections. Furthermore, we outlined the recent progress by our group and others in understanding the sub-cellular genomic changes that lead to antibiotic resistance in these organisms. Finally, we discussed in detail, the novel therapies and drug delivery systems in development for the efficacious management of bacterial keratitis.
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Affiliation(s)
- Rohan Bir Singh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA; Department of Ophthalmology, Leiden University Medical Center, 2333, ZA Leiden, the Netherlands
| | - Sujata Das
- Cornea and Anterior Segment Services, LV Prasad Eye Institute, Bhubaneshwar, India
| | - James Chodosh
- Department of Ophthalmology, Massachusetts Eye and Ear, Harvard Medical School, Boston, MA, USA
| | - Namrata Sharma
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
| | - Michael E Zegans
- Department of Ophthalmology, Geisel School of Medicine at Dartmouth, Hanover, NH, USA
| | - Regis P Kowalski
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Vishal Jhanji
- Department of Ophthalmology, University of Pittsburgh Medical Center, Pittsburgh, PA, USA; The Charles T Campbell Ophthalmic Microbiology Laboratory, University of Pittsburgh Medical Center, Pittsburgh, PA, USA.
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Zoratto N, Forcina L, Matassa R, Mosca L, Familiari G, Musarò A, Mattei M, Coviello T, Di Meo C, Matricardi P. Hyaluronan-Cholesterol Nanogels for the Enhancement of the Ocular Delivery of Therapeutics. Pharmaceutics 2021; 13:pharmaceutics13111781. [PMID: 34834195 PMCID: PMC8619261 DOI: 10.3390/pharmaceutics13111781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 10/17/2021] [Accepted: 10/22/2021] [Indexed: 12/31/2022] Open
Abstract
The anatomy and physiology of the eye strongly limit the bioavailability of locally administered drugs. The entrapment of therapeutics into nanocarriers represents an effective strategy for the topical treatment of several ocular disorders, as they may protect the embedded molecules, enabling drug residence on the ocular surface and/or its penetration into different ocular compartments. The present work shows the activity of hyaluronan-cholesterol nanogels (NHs) as ocular permeation enhancers. Thanks to their bioadhesive properties, NHs firmly interact with the superficial corneal epithelium, without penetrating the stroma, thus modifying the transcorneal penetration of loaded therapeutics. Ex vivo transcorneal permeation experiments show that the permeation of hydrophilic drugs (i.e., tobramycin and diclofenac sodium salt), loaded in NHs, is significantly enhanced when compared to the free drug solutions. On the other side, the permeation of hydrophobic drugs (i.e., dexamethasone and piroxicam) is strongly dependent on the water solubility of the entrapped molecules. The obtained results suggest that NHs formulations can improve the ocular bioavailability of the instilled drugs by increasing their preocular retention time (hydrophobic drugs) or facilitating their permeation (hydrophilic drugs), thus opening the route for the application of HA-based NHs in the treatment of both anterior and posterior eye segment diseases.
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Affiliation(s)
- Nicole Zoratto
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, 00185 Roma, Italy; (N.Z.); (T.C.); (C.D.M.)
| | - Laura Forcina
- DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Via A. Scarpa, 14, 00161 Rome, Italy; (L.F.); (A.M.)
| | - Roberto Matassa
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Section of Human Anatomy, Sapienza University of Rome, Via A. Borelli 50, 00161 Rome, Italy; (R.M.); (G.F.)
| | - Luciana Mosca
- Department of Biochemical Sciences “A. Rossi Fanelli”, Sapienza University of Rome, 00185 Roma, Italy;
| | - Giuseppe Familiari
- Department of Anatomical, Histological, Forensic and Orthopaedic Sciences, Section of Human Anatomy, Sapienza University of Rome, Via A. Borelli 50, 00161 Rome, Italy; (R.M.); (G.F.)
| | - Antonio Musarò
- DAHFMO-Unit of Histology and Medical Embryology, Sapienza University of Rome, Via A. Scarpa, 14, 00161 Rome, Italy; (L.F.); (A.M.)
| | - Maurizio Mattei
- Interdepartmental Center for Comparative Medicine, Alternative Techniques and Aquaculture (CIMETA), University of Rome “Tor Vergata”, Via Montpellier 1, 00133 Rome, Italy;
- Department of Biology, University of Rome “Tor Vergata”, Via della Ricerca Scientifica 1, 00133 Rome, Italy
| | - Tommasina Coviello
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, 00185 Roma, Italy; (N.Z.); (T.C.); (C.D.M.)
| | - Chiara Di Meo
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, 00185 Roma, Italy; (N.Z.); (T.C.); (C.D.M.)
| | - Pietro Matricardi
- Department of Drug Chemistry and Technologies, Sapienza University of Rome, 00185 Roma, Italy; (N.Z.); (T.C.); (C.D.M.)
- Correspondence:
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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: 26] [Impact Index Per Article: 8.7] [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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Morin CD, Déziel E, Gauthier J, Levesque RC, Lau GW. An Organ System-Based Synopsis of Pseudomonas aeruginosa Virulence. Virulence 2021; 12:1469-1507. [PMID: 34180343 PMCID: PMC8237970 DOI: 10.1080/21505594.2021.1926408] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Driven in part by its metabolic versatility, high intrinsic antibiotic resistance, and a large repertoire of virulence factors, Pseudomonas aeruginosa is expertly adapted to thrive in a wide variety of environments, and in the process, making it a notorious opportunistic pathogen. Apart from the extensively studied chronic infection in the lungs of people with cystic fibrosis (CF), P. aeruginosa also causes multiple serious infections encompassing essentially all organs of the human body, among others, lung infection in patients with chronic obstructive pulmonary disease, primary ciliary dyskinesia and ventilator-associated pneumonia; bacteremia and sepsis; soft tissue infection in burns, open wounds and postsurgery patients; urinary tract infection; diabetic foot ulcers; chronic suppurative otitis media and otitis externa; and keratitis associated with extended contact lens use. Although well characterized in the context of CF, pathogenic processes mediated by various P. aeruginosa virulence factors in other organ systems remain poorly understood. In this review, we use an organ system-based approach to provide a synopsis of disease mechanisms exerted by P. aeruginosa virulence determinants that contribute to its success as a versatile pathogen.
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Affiliation(s)
- Charles D Morin
- Centre Armand-Frappier Santé Biotechnologie, Institut National De La Recherche Scientifique (INRS), Laval, Quebec, Canada
| | - Eric Déziel
- Centre Armand-Frappier Santé Biotechnologie, Institut National De La Recherche Scientifique (INRS), Laval, Quebec, Canada
| | - Jeff Gauthier
- Département De Microbiologie-infectiologie Et Immunologie, Institut De Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec City, Quebec, Canada
| | - Roger C Levesque
- Département De Microbiologie-infectiologie Et Immunologie, Institut De Biologie Intégrative Et Des Systèmes (IBIS), Université Laval, Québec City, Quebec, Canada
| | - Gee W Lau
- Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, IL, US
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7
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Conde Penedo A, Díaz Tomé V, Fernández Ferreiro A, González Barcia M, Otero Espinar FJ. Enhancement in corneal permeability of riboflavin using cyclodextrin derivates complexes as a previous step to transepithelial cross-linking. Eur J Pharm Biopharm 2021; 162:12-22. [PMID: 33667681 DOI: 10.1016/j.ejpb.2021.02.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 02/15/2021] [Accepted: 02/23/2021] [Indexed: 01/14/2023]
Abstract
Corneal cross-linking has been described as an effective treatment to slow the progression of keratoconus. The standard protocol entails corneal epithelial removal to allow the diffusion of riboflavin into the stroma. Although, de-epithelization can generate risks or complications that transepithelial cross-linking tries to solve or avoid. Different formulations were developed after verifying that hydroxypropyl-β-cyclodextrin (HPβCD) and sulfobuthylether-β-cyclodextrin (SBEβCD) in a 20% concentration, increased the solubility of practically insoluble in water drugs such as riboflavin from 0.12 mg/mL to 0.35 mg/mL and 0.29 mg/mL respectively. These values were higher when chitosan and arginine were added to the formulation, showing solubility of 0.78 mg/mL when HPβCD concentration was not modified. Ex vivo corneal permeability was measured after having kept in contact bovine corneas with intact epithelium for 5 h with the 0.1 mg/mL riboflavin solution, the formulations developed and a reproduced nanoemulsion from another work. Riboflavin's permeability was increased when cyclodextrins, chitosan, and arginine were part of the formulations, compared to the control drug solution. The best permeability coefficient was reached when riboflavin was combined with 40% (w/v) HPβCD, 0.5% (w/w) arginine, and 0.5% (w/w) chitosan. After having carried out toxicity studies as bovine corneal opacity and permeability (BCOP) and Heńs Egg Test - Chorioallantoic Membrane Test (HET-CAM) it was verified that both, the active ingredients and the excipients of the different formulations were not harmful without generating irritation, loss of transparency or corneal permeability alterations. The results show the great potential of the ocular developed solution for their use in transepithelial cross-linking for keratoconus treatment.
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Affiliation(s)
- Andrea Conde Penedo
- Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain; Paraquasil Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Victoria Díaz Tomé
- Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain; Clinical Pharmacology Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain
| | - Anxo Fernández Ferreiro
- Pharmacy Department, University Clinical Hospital Santiago de Compostela, Santiago de Compostela, Spain; Clinical Pharmacology Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.
| | - Miguel González Barcia
- Pharmacy Department, University Clinical Hospital Santiago de Compostela, Santiago de Compostela, Spain; Clinical Pharmacology Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.
| | - Francisco J Otero Espinar
- Department of Pharmacology, Pharmacy and Pharmaceutical Technology, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain; Paraquasil Group, University Clinical Hospital, Health Research Institute of Santiago de Compostela, Santiago de Compostela, Spain.
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The Role of Pseudomonas aeruginosa Lipopolysaccharide in Bacterial Pathogenesis and Physiology. Pathogens 2019; 9:pathogens9010006. [PMID: 31861540 PMCID: PMC7168646 DOI: 10.3390/pathogens9010006] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/15/2019] [Accepted: 12/17/2019] [Indexed: 12/13/2022] Open
Abstract
The major constituent of the outer membrane of Gram-negative bacteria is lipopolysaccharide (LPS), which is comprised of lipid A, core oligosaccharide, and O antigen, which is a long polysaccharide chain extending into the extracellular environment. Due to the localization of LPS, it is a key molecule on the bacterial cell wall that is recognized by the host to deploy an immune defence in order to neutralize invading pathogens. However, LPS also promotes bacterial survival in a host environment by protecting the bacteria from these threats. This review explores the relationship between the different LPS glycoforms of the opportunistic pathogen Pseudomonas aeruginosa and the ability of this organism to cause persistent infections, especially in the genetic disease cystic fibrosis. We also discuss the role of LPS in facilitating biofilm formation, antibiotic resistance, and how LPS may be targeted by new antimicrobial therapies.
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Fleiszig SMJ, Kroken AR, Nieto V, Grosser MR, Wan SJ, Metruccio MME, Evans DJ. Contact lens-related corneal infection: Intrinsic resistance and its compromise. Prog Retin Eye Res 2019; 76:100804. [PMID: 31756497 DOI: 10.1016/j.preteyeres.2019.100804] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Revised: 11/05/2019] [Accepted: 11/12/2019] [Indexed: 12/20/2022]
Abstract
Contact lenses represent a widely utilized form of vision correction with more than 140 million wearers worldwide. Although generally well-tolerated, contact lenses can cause corneal infection (microbial keratitis), with an approximate annualized incidence ranging from ~2 to ~20 cases per 10,000 wearers, and sometimes resulting in permanent vision loss. Research suggests that the pathogenesis of contact lens-associated microbial keratitis is complex and multifactorial, likely requiring multiple conspiring factors that compromise the intrinsic resistance of a healthy cornea to infection. Here, we outline our perspective of the mechanisms by which contact lens wear sometimes renders the cornea susceptible to infection, focusing primarily on our own research efforts during the past three decades. This has included studies of host factors underlying the constitutive barrier function of the healthy cornea, its response to bacterial challenge when intrinsic resistance is not compromised, pathogen virulence mechanisms, and the effects of contact lens wear that alter the outcome of host-microbe interactions. For almost all of this work, we have utilized the bacterium Pseudomonas aeruginosa because it is the leading cause of lens-related microbial keratitis. While not yet common among corneal isolates, clinical isolates of P. aeruginosa have emerged that are resistant to virtually all currently available antibiotics, leading the United States CDC (Centers for Disease Control) to add P. aeruginosa to its list of most serious threats. Compounding this concern, the development of advanced contact lenses for biosensing and augmented reality, together with the escalating incidence of myopia, could portent an epidemic of vision-threatening corneal infections in the future. Thankfully, technological advances in genomics, proteomics, metabolomics and imaging combined with emerging models of contact lens-associated P. aeruginosa infection hold promise for solving the problem - and possibly life-threatening infections impacting other tissues.
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Affiliation(s)
- Suzanne M J Fleiszig
- School of Optometry, University of California, Berkeley, CA, USA; Graduate Group in Vision Science, University of California, Berkeley, CA, USA; Graduate Groups in Microbiology and Infectious Diseases & Immunity, University of California, Berkeley, CA, USA.
| | - Abby R Kroken
- School of Optometry, University of California, Berkeley, CA, USA
| | - Vincent Nieto
- School of Optometry, University of California, Berkeley, CA, USA
| | | | - Stephanie J Wan
- Graduate Group in Vision Science, University of California, Berkeley, CA, USA
| | | | - David J Evans
- School of Optometry, University of California, Berkeley, CA, USA; College of Pharmacy, Touro University California, Vallejo, CA, USA
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Garg P, Venuganti VVK, Roy A, Roy G. Novel drug delivery methods for the treatment of keratitis: moving away from surgical intervention. Expert Opin Drug Deliv 2019; 16:1381-1391. [PMID: 31701781 DOI: 10.1080/17425247.2019.1690451] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Introduction: Corneal ulceration is one of the leading causes of blindness especially in low- and mid-income countries (LMICs). Surgical treatment of microbial keratitis is associated with multiple challenges that include non-availability of donor corneal tissues, lack of trained corneal surgeons, and poor compliance to follow up care. As a result, the surgery fails in 70-90% cases. Therefore, improving outcome of medical treatment and thereby avoiding the need for the surgery is an unmet need in the care of corneal ulcer cases.Areas covered: In this review article, the authors have tried to compile information on the novel drug-delivery systems that have potential to enhance success of medical management. We have discussed the following systems: cyclodextrins, gel formulations, colloidal system, nanoformulations, drug-eluting contact lens, microneedle patch, and ocular inserts.Expert opinion: The goals of corneal ulcer treatment are as follows: rapid eradication of causative microorganisms, control of damage from induced inflammation and microbial toxins, and facilitation of repair. The ocular surface anatomy poses several challenges for drug delivery using standard topical therapy. The novel drug-delivery systems mentioned above aim to enhanced tear solubility; superior stability; improved bio-availability; reduced toxicity; besides facilitating targeted drug delivery and convenience of administration.
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Affiliation(s)
- Prashant Garg
- Tej Kohli Cornea Institute, KAR campus, L. V. Prasad Eye Institute, Hyderabad, India
| | | | - Aravind Roy
- Tej Kohli Cornea Institute, KVC campus, L. V. Prasad Eye Institute, Vijayawada, India
| | - Girdhari Roy
- Department of Pharmacology, Birla Institute of Technology and Science (BITS) Pilani, Hyderabad, India
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11
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Ruffin M, Brochiero E. Repair Process Impairment by Pseudomonas aeruginosa in Epithelial Tissues: Major Features and Potential Therapeutic Avenues. Front Cell Infect Microbiol 2019; 9:182. [PMID: 31214514 PMCID: PMC6554286 DOI: 10.3389/fcimb.2019.00182] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 05/13/2019] [Indexed: 01/13/2023] Open
Abstract
Epithelial tissues protecting organs from the environment are the first-line of defense against pathogens. Therefore, efficient repair mechanisms after injury are crucial to maintain epithelial integrity. However, these healing processes can be insufficient to restore epithelial integrity, notably in infectious conditions. Pseudomonas aeruginosa infections in cutaneous, corneal, and respiratory tract epithelia are of particular concern because they are the leading causes of hospitalizations, disabilities, and deaths worldwide. Pseudomonas aeruginosa has been shown to alter repair processes, leading to chronic wounds and infections. Because of the current increase in the incidence of multi-drug resistant isolates of P. aeruginosa, complementary approaches to decrease the negative impact of these bacteria on epithelia are urgently needed. Here, we review the recent advances in the understanding of the impact of P. aeruginosa infections on the integrity and repair mechanisms of alveolar, airway, cutaneous and corneal epithelia. Potential therapeutic avenues aimed at counteracting this deleterious impact of infection are also discussed.
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Affiliation(s)
- Manon Ruffin
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada.,INSERM, Centre de Recherche Saint-Antoine, CRSA, Sorbonne Université, Paris, France
| | - Emmanuelle Brochiero
- Centre de Recherche du Centre Hospitalier de l'Université de Montréal (CRCHUM), Montréal, QC, Canada.,Département de Médecine, Université de Montréal, Montréal, QC, Canada
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12
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Chhuon C, Pranke I, Borot F, Tondelier D, Lipecka J, Fritsch J, Chanson M, Edelman A, Ollero M, Guerrera I. Changes in lipid raft proteome upon TNF-α stimulation of cystic fibrosis cells. J Proteomics 2016; 145:246-253. [DOI: 10.1016/j.jprot.2016.07.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 05/20/2016] [Accepted: 07/03/2016] [Indexed: 01/22/2023]
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13
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Abu-Arish A, Pandzic E, Goepp J, Matthes E, Hanrahan JW, Wiseman PW. Cholesterol modulates CFTR confinement in the plasma membrane of primary epithelial cells. Biophys J 2016; 109:85-94. [PMID: 26153705 DOI: 10.1016/j.bpj.2015.04.042] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 04/23/2015] [Indexed: 01/01/2023] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) is a plasma-membrane anion channel that, when mutated, causes the disease cystic fibrosis. Although CFTR has been detected in a detergent-resistant membrane fraction prepared from airway epithelial cells, suggesting that it may partition into cholesterol-rich membrane microdomains (lipid rafts), its compartmentalization has not been demonstrated in intact cells and the influence of microdomains on CFTR lateral mobility is unknown. We used live-cell imaging, spatial image correlation spectroscopy, and k-space image correlation spectroscopy to examine the aggregation state of CFTR and its dynamics both within and outside microdomains in the plasma membrane of primary human bronchial epithelial cells. These studies were also performed during treatments that augment or deplete membrane cholesterol. We found two populations of CFTR molecules that were distinguishable based on their dynamics at the cell surface. One population showed confinement and had slow dynamics that were highly cholesterol dependent. The other, more abundant population was less confined and diffused more rapidly. Treatments that deplete the membrane of cholesterol caused the confined fraction and average number of CFTR molecules per cluster to decrease. Elevating cholesterol had the opposite effect, increasing channel aggregation and the fraction of channels displaying confinement, consistent with CFTR recruitment into cholesterol-rich microdomains with dimensions below the optical resolution limit. Viral infection caused the nanoscale microdomains to fuse into large platforms and reduced CFTR mobility. To our knowledge, these results provide the first biophysical evidence for multiple CFTR populations and have implications for regulation of their surface expression and channel function.
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Affiliation(s)
| | - Elvis Pandzic
- Physics, McGill University, Montreal, Quebec, Canada
| | - Julie Goepp
- Physiology, McGill University, Montreal, Quebec, Canada
| | | | | | - Paul W Wiseman
- Chemistry & Physics, McGill University, Montreal, Quebec, Canada.
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Toledo A, Benach JL. Hijacking and Use of Host Lipids by Intracellular Pathogens. Microbiol Spectr 2015; 3:10.1128/microbiolspec.VMBF-0001-2014. [PMID: 27337282 PMCID: PMC5790186 DOI: 10.1128/microbiolspec.vmbf-0001-2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Indexed: 12/14/2022] Open
Abstract
Intracellular bacteria use a number of strategies to survive, grow, multiply, and disseminate within the host. One of the most striking adaptations that intracellular pathogens have developed is the ability to utilize host lipids and their metabolism. Bacteria such as Anaplasma, Chlamydia, or Mycobacterium can use host lipids for different purposes, such as a means of entry through lipid rafts, building blocks for bacteria membrane formation, energy sources, camouflage to avoid the fusion of phagosomes and lysosomes, and dissemination. One of the most extreme examples of lipid exploitation is Mycobacterium, which not only utilizes the host lipid as a carbon and energy source but is also able to reprogram the host lipid metabolism. Likewise, Chlamydia spp. have also developed numerous mechanisms to reprogram lipids onto their intracellular inclusions. Finally, while the ability to exploit host lipids is important in intracellular bacteria, it is not an exclusive trait. Extracellular pathogens, including Helicobacter, Mycoplasma, and Borrelia, can recruit and metabolize host lipids that are important for their growth and survival.Throughout this chapter we will review how intracellular and extracellular bacterial pathogens utilize host lipids to enter, survive, multiply, and disseminate in the host.
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Affiliation(s)
- Alvaro Toledo
- Department of Molecular Genetics and Microbiology, Stony Brook University, Center for Infectious Diseases at the Center for Molecular Medicine, Stony Brook, NY 11794
| | - Jorge L Benach
- Department of Molecular Genetics and Microbiology, Stony Brook University, Center for Infectious Diseases at the Center for Molecular Medicine, Stony Brook, NY 11794
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Hussain R, Shahror R, Karpati F, Roomans GM. Glucocorticoids can affectPseudomonas aeruginosa(ATCC 27853) internalization and intracellular calcium concentration in cystic fibrosis bronchial epithelial cells. Exp Lung Res 2015; 41:383-92. [DOI: 10.3109/01902148.2015.1046199] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Ni I, Ji C, Vij N. Second-hand cigarette smoke impairs bacterial phagocytosis in macrophages by modulating CFTR dependent lipid-rafts. PLoS One 2015; 10:e0121200. [PMID: 25794013 PMCID: PMC4368805 DOI: 10.1371/journal.pone.0121200] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 01/27/2015] [Indexed: 01/08/2023] Open
Abstract
Introduction First/Second-hand cigarette-smoke (FHS/SHS) exposure weakens immune defenses inducing chronic obstructive pulmonary disease (COPD) but the underlying mechanisms are not fully understood. Hence, we evaluated if SHS induced changes in membrane/lipid-raft (m-/r)-CFTR (cystic fibrosis transmembrane conductance regulator) expression/activity is a potential mechanism for impaired bacterial phagocytosis in COPD. Methods RAW264.7 murine macrophages were exposed to freshly prepared CS-extract (CSE) containing culture media and/or Pseudomonas-aeruginosa-PA01-GFP for phagocytosis (fluorescence-microscopy), bacterial survival (colony-forming-units-CFU), and immunoblotting assays. The CFTR-expression/activity and lipid-rafts were modulated by transient-transfection or inhibitors/inducers. Next, mice were exposed to acute/sub-chronic-SHS or room-air (5-days/3-weeks) and infected with PA01-GFP, followed by quantification of bacterial survival by CFU-assay. Results We investigated the effect of CSE treatment on RAW264.7 cells infected by PA01-GFP and observed that CSE treatment significantly (p<0.01) inhibits PA01-GFP phagocytosis as compared to the controls. We also verified this in murine model, exposed to acute/sub-chronic-SHS and found significant (p<0.05, p<0.02) increase in bacterial survival in the SHS-exposed lungs as compared to the room-air controls. Next, we examined the effect of impaired CFTR ion-channel-activity on PA01-GFP infection of RAW264.7 cells using CFTR172-inhibitor and found no significant change in phagocytosis. We also similarly evaluated the effect of a CFTR corrector-potentiator compound, VRT-532, and observed no significant rescue of CSE impaired PA01-GFP phagocytosis although it significantly (p<0.05) decreases CSE induced bacterial survival. Moreover, induction of CFTR expression in macrophages significantly (p<0.03) improves CSE impaired PA01-GFP phagocytosis as compared to the control. Next, we verified the link between m-/r-CFTR expression and phagocytosis using methyl-β-cyclodextran (CD), as it is known to deplete CFTR from membrane lipid-rafts. We observed that CD treatment significantly (p<0.01) inhibits bacterial phagocytosis in RAW264.7 cells and adding CSE further impairs phagocytosis suggesting synergistic effect on CFTR dependent lipid-rafts. Conclusion Our data suggest that SHS impairs bacterial phagocytosis by modulating CFTR dependent lipid-rafts.
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Affiliation(s)
- Inzer Ni
- Department of Pediatric Respiratory Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Changhoon Ji
- Department of Pediatric Respiratory Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Neeraj Vij
- Department of Pediatric Respiratory Science, The Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Department of Foundational Sciences, College of Medicine, Central Michigan University, Mount Pleasant, Michigan, United States of America
- * E-mail:
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Pseudomonas aeruginosa-induced bleb-niche formation in epithelial cells is independent of actinomyosin contraction and enhanced by loss of cystic fibrosis transmembrane-conductance regulator osmoregulatory function. mBio 2015; 6:e02533. [PMID: 25714715 PMCID: PMC4358002 DOI: 10.1128/mbio.02533-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The opportunistic pathogen Pseudomonas aeruginosa can infect almost any site in the body but most often targets epithelial cell-lined tissues such as the airways, skin, and the cornea of the eye. A common predisposing factor is cystic fibrosis (CF), caused by defects in the cystic fibrosis transmembrane-conductance regulator (CFTR). Previously, we showed that when P. aeruginosa enters epithelial cells it replicates intracellularly and occupies plasma membrane blebs. This phenotype is dependent on the type 3 secretion system (T3SS) effector ExoS, shown by others to induce host cell apoptosis. Here, we examined mechanisms for P. aeruginosa-induced bleb formation, focusing on its relationship to apoptosis and the CFTR. The data showed that P. aeruginosa-induced blebbing in epithelial cells is independent of actin contraction and is inhibited by hyperosmotic media (400 to 600 mOsM), distinguishing bacterially induced blebs from apoptotic blebs. Cells with defective CFTR displayed enhanced bleb formation upon infection, as demonstrated using bronchial epithelial cells from a patient with cystic fibrosis and a CFTR inhibitor, CFTR(Inh)-172. The defect was found to be correctable either by incubation in hyperosmotic media or by complementation with CFTR (pGFP-CFTR), suggesting that the osmoregulatory function of CFTR counters P. aeruginosa-induced bleb-niche formation. Accordingly, and despite their reduced capacity for bacterial internalization, CFTR-deficient cells showed greater bacterial occupation of blebs and enhanced intracellular replication. Together, these data suggest that P. aeruginosa bleb niches are distinct from apoptotic blebs, are driven by osmotic forces countered by CFTR, and could provide a novel mechanism for bacterial persistence in the host. Pseudomonas aeruginosa is an opportunistic pathogen problematic in hospitalized patients and those with cystic fibrosis (CF). Previously, we showed that P. aeruginosa can enter epithelial cells and replicate within them and traffics to the membrane blebs that it induces. This “bleb-niche” formation requires ExoS, previously shown to cause apoptosis. Here, we show that the driving force for bleb-niche formation is osmotic pressure, differentiating P. aeruginosa-induced blebs from apoptotic blebs. Either CFTR inhibition or CFTR mutation (as seen in people with CF) causes P. aeruginosa to make more bleb niches and provides an osmotic driving force for blebbing. CFTR inhibition also enhances bacterial occupation of blebs and intracellular replication. Since CFTR is targeted for removal from the plasma membrane when P. aeruginosa invades a healthy cell, these findings could relate to pathogenesis in both CF and healthy patient populations.
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Priebe GP, Goldberg JB. Vaccines for Pseudomonas aeruginosa: a long and winding road. Expert Rev Vaccines 2014; 13:507-19. [PMID: 24575895 DOI: 10.1586/14760584.2014.890053] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Despite the recognition of Pseudomonas aeruginosa as an opportunistic pathogen, no vaccine against this bacteria has come to market. This review describes the current state-of-the-art in vaccinology for this bacterium. This includes a discussion of those at risk for infection, the types of vaccines and the approaches for empirical and targeted antigen selection under development, as well as a perspective on where the field should go. In addition, the challenges in developing a vaccine for those individuals at risk are discussed.
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Choosing an appropriate infection model to study quorum sensing inhibition in Pseudomonas infections. Int J Mol Sci 2013; 14:19309-40. [PMID: 24065108 PMCID: PMC3794835 DOI: 10.3390/ijms140919309] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2013] [Revised: 09/13/2013] [Accepted: 09/17/2013] [Indexed: 02/07/2023] Open
Abstract
Bacteria, although considered for decades to be antisocial organisms whose sole purpose is to find nutrients and multiply are, in fact, highly communicative organisms. Referred to as quorum sensing, cell-to-cell communication mechanisms have been adopted by bacteria in order to co-ordinate their gene expression. By behaving as a community rather than as individuals, bacteria can simultaneously switch on their virulence factor production and establish successful infections in eukaryotes. Understanding pathogen-host interactions requires the use of infection models. As the use of rodents is limited, for ethical considerations and the high costs associated with their use, alternative models based on invertebrates have been developed. Invertebrate models have the benefits of low handling costs, limited space requirements and rapid generation of results. This review presents examples of such models available for studying the pathogenicity of the Gram-negative bacterium Pseudomonas aeruginosa. Quorum sensing interference, known as quorum quenching, suggests a promising disease-control strategy since quorum-quenching mechanisms appear to play important roles in microbe-microbe and host-pathogen interactions. Examples of natural and synthetic quorum sensing inhibitors and their potential as antimicrobials in Pseudomonas-related infections are discussed in the second part of this review.
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Reidy T, Rittenberg A, Dwyer M, D'Ortona S, Pier G, Gadjeva M. Homotrimeric macrophage migration inhibitory factor (MIF) drives inflammatory responses in the corneal epithelium by promoting caveolin-rich platform assembly in response to infection. J Biol Chem 2013; 288:8269-8278. [PMID: 23372160 DOI: 10.1074/jbc.m112.351064] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Acute inflammation that arises during Pseudomonas aeruginosa-induced ocular infection can trigger tissue damage resulting in long term impairment of visual function, suggesting that the appropriate treatment strategy should include the use of anti-inflammatory agents in addition to antibiotics. We recently identified a potential target for modulation during ocular infection, macrophage migration inhibitory factor (MIF). MIF deficiency protected mice from inflammatory-mediated corneal damage resulting from acute bacterial keratitis. To gain a better understanding of the molecular mechanisms of MIF activity, we analyzed the oligomeric states and functional properties of MIF during infection. We found that in human primary corneal cells infected with P. aeruginosa, MIF is primarily in a homotrimeric state. Homotrimeric MIF levels correlated with the severity of infection in the corneas of infected mice, suggesting that the MIF homotrimers were the functionally active form of MIF. During infection, human primary corneal cells released more IL-8 when treated with recombinant, locked MIF trimers than when treated with lower MIF oligomers. MIF promoted P. aeruginosa-induced IL-8 responses via the formation of caveolin-1-rich "signaling hubs" in the corneal cells that led to elevated MAPK p42/p44 activation and sustained inflammatory signaling. These findings suggest that inhibiting homotrimerization of MIF or the functional activities of MIF homotrimers could have therapeutic benefits during ocular inflammation.
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Affiliation(s)
- Thomas Reidy
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Alexander Rittenberg
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Markryan Dwyer
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Samantha D'Ortona
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Gerald Pier
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115
| | - Mihaela Gadjeva
- Division of Infectious Disease, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115.
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Morrison PWJ, Connon CJ, Khutoryanskiy VV. Cyclodextrin-mediated enhancement of riboflavin solubility and corneal permeability. Mol Pharm 2013; 10:756-62. [PMID: 23294178 DOI: 10.1021/mp3005963] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cyclodextrins are water-soluble cyclic oligosaccharides consisting of six, seven, and eight α-(1,4)-linked glucopyranose subunits. This study reports the use of different cyclodextrins in eye drop formulations to improve the aqueous solubility and corneal permeability of riboflavin. Riboflavin is a poorly soluble drug with a solubility up to 0.08 mg mL(-1) in deionized water. It is used as a drug topically administered to the eye to mediate UV-induced corneal cross-linking in the treatment of keratoconus. Aqueous solutions of β-cyclodextrin (10-30 mg mL(-1)) can enhance the solubility of riboflavin up to 0.12-0.19 mg mL(-1), whereas the higher concentration of α-cyclodextrin (100 mg mL(-1)) achieved a lower level of enhancement of 0.11 mg mL(-1). The other oligosaccharides were found to be inefficient for this purpose. In vitro diffusion experiments performed with fresh and cryopreserved bovine cornea have demonstrated that β-cyclodextrin enhances riboflavin permeability. The mechanism of this enhancement was examined through microscopic histological analysis of the cornea and is discussed in this paper.
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Affiliation(s)
- Peter W J Morrison
- School of Pharmacy, University of Reading , Whiteknights, P.O. Box 224, Reading, RG6 6AD, United Kingdom
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Sun Y, Karmakar M, Taylor PR, Rietsch A, Pearlman E. ExoS and ExoT ADP ribosyltransferase activities mediate Pseudomonas aeruginosa keratitis by promoting neutrophil apoptosis and bacterial survival. THE JOURNAL OF IMMUNOLOGY 2012; 188:1884-95. [PMID: 22250085 DOI: 10.4049/jimmunol.1102148] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Pseudomonas aeruginosa is a leading cause of blinding corneal ulcers worldwide. To determine the role of type III secretion in the pathogenesis of P. aeruginosa keratitis, corneas of C57BL/6 mice were infected with P. aeruginosa strain PAO1 or PAK, which expresses ExoS, ExoT, and ExoY, but not ExoU. PAO1- and PAK-infected corneas developed severe disease with pronounced opacification and rapid bacterial growth. In contrast, corneas infected with ΔpscD or ΔpscJ mutants that cannot assemble a type III secretion system, or with mutants lacking the translocator proteins, do not develop clinical disease, and bacteria are rapidly killed by infiltrating neutrophils. Furthermore, survival of PAO1 and PAK strains in the cornea and development of corneal disease was impaired in ΔexoS, ΔexoT, and ΔexoST mutants of both strains, but not in a ΔexoY mutant. ΔexoST mutants were also rapidly killed in neutrophils in vitro and were impaired in their ability to promote neutrophil apoptosis in vivo compared with PAO1. Point mutations in the ADP ribosyltransferase (ADPR) regions of ExoS or ExoT also impaired proapoptotic activity in infected neutrophils, and exoST(ADPR-) mutants replicated the ΔexoST phenotype in vitro and in vivo, whereas mutations in rho-GTPase-activating protein showed the same phenotype as PAO1. Together, these findings demonstrate that the pathogenesis of P. aeruginosa keratitis in ExoS- and ExoT-producing strains is almost entirely due to their ADPR activities, which subvert the host response by targeting the antibacterial activity of infiltrating neutrophils.
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Affiliation(s)
- Yan Sun
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
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Dihydroceramide desaturase and dihydrosphingolipids: debutant players in the sphingolipid arena. Prog Lipid Res 2011; 51:82-94. [PMID: 22200621 DOI: 10.1016/j.plipres.2011.12.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
Sphingolipids are a wide family of lipids that share common sphingoid backbones, including (2S,3R)-2-amino-4-octadecane-1,3-diol (dihydrosphingosine) and (2S,3R,4E)-2-amino-4-octadecene-1,3-diol (sphingosine). The metabolism and biological functions of sphingolipids derived from sphingosine have been the subject of many reviews. In contrast, dihydrosphingolipids have received poor attention, mainly due to their supposed lack of biological activity. However, the reported biological effects of active site directed dihydroceramide desaturase inhibitors and the involvement of dihydrosphingolipids in the response of cells to known therapeutic agents support that dihydrosphingolipids are not inert but are in fact biologically active and underscore the importance of elucidating further the metabolic pathways and cell signaling networks involved in the biological activities of dihydrosphingolipids. Dihydroceramide desaturase is the enzyme involved in the conversion of dihydroceramide into ceramide and it is crucial in the regulation of the balance between sphingolipids and dihydrosphingolipids. Furthermore, given the enzyme requirement for O₂ and the NAD(P)H cofactor, the cellular redox balance and dihydroceramide desaturase activity may reciprocally influence each other. In this review both dihydroceramide desaturase and the biological functions of dihydrosphingolipids are addressed and perspectives on this field are discussed.
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Jahn KA, Su Y, Braet F. Multifaceted nature of membrane microdomains in colorectal cancer. World J Gastroenterol 2011; 17:681-90. [PMID: 21390137 PMCID: PMC3042645 DOI: 10.3748/wjg.v17.i6.681] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2010] [Revised: 11/23/2010] [Accepted: 11/30/2010] [Indexed: 02/06/2023] Open
Abstract
Membrane microdomains or lipid rafts are known to be highly dynamic and to act as selective signal transduction mediators that facilitate interactions between the cell’s external and internal environments. Lipid rafts play an important mediating role in the biology of cancer: they have been found in almost all existing experimental cancer models, including colorectal cancer (CRC), and play key regulatory roles in cell migration, metastasis, cell survival and tumor progression. This paper explores the current state of knowledge in this field by highlighting some of the pioneering and recent lipid raft studies performed on different CRC cell lines and human tissue samples. From this literature review, it becomes clear that membrane microdomains appear to be implicated in all key intracellular signaling pathways for lipid metabolism, drug resistance, cell adhesion, cell death, cell proliferation and many other processes in CRC. All signal transduction pathways seem to originate directly from those peculiar lipid islands, thereby orchestrating the colon cancer cells’ state and fate. As confirmed by recent animal and preclinical studies in different CRC models, continuing to unravel the structure and function of lipid rafts - including their associated complex signaling pathways - will likely bring us one step closer to better monitoring and treating of colon cancer patients.
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Animal models of bacterial keratitis. J Biomed Biotechnol 2011; 2011:680642. [PMID: 21274270 PMCID: PMC3022227 DOI: 10.1155/2011/680642] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2010] [Revised: 11/29/2010] [Accepted: 12/09/2010] [Indexed: 11/20/2022] Open
Abstract
Bacterial keratitis is a disease of the cornea characterized by pain, redness, inflammation, and opacity. Common causes of this disease are Pseudomonas aeruginosa and Staphylococcus aureus. Animal models of keratitis have been used to elucidate both the bacterial factors and the host inflammatory response involved in the disease. Reviewed herein are animal models of bacterial keratitis and some of the key findings in the last several decades.
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Emam A, Carter WG, Lingwood C. Glycolipid-Dependent, Protease Sensitive Internalization of Pseudomonas aeruginosa Into Cultured Human Respiratory Epithelial Cells. Open Microbiol J 2010; 4:106-15. [PMID: 21270937 PMCID: PMC3026333 DOI: 10.2174/1874285801004010106] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 10/12/2010] [Accepted: 10/14/2010] [Indexed: 11/27/2022] Open
Abstract
Internalization of PAK strain Pseudomonas aeruginosa into human respiratory epithelial cell lines and HeLa cervical cancer cells in vitro was readily demonstrable via a gentamycin protection assay. Depletion of target cell glycosphingolipids (GSLs) using a glucosyl ceramide synthase inhibitor, P4, completely prevented P. aeruginosa internalization. In contrast, P4 treatment had no effect on the internalization of Salmonella typhimurium into HeLa cells. Internalized P. aeruginosa were within membrane vacuoles, often containing microvesicles, between the bacterium and the limiting membrane. P. aeruginosa internalization was markedly enhanced by target cell pretreatment with the exogenous GSL, deacetyl gangliotetraosyl ceramide (Gg4). Gg4 binds the lipid raft marker, GM1 ganglioside. Target cell pretreatment with TLCK, but not other (serine) protease inhibitors, prevented both P. aeruginosa host cell binding and internalization. NFkB inhibition also prevented internalization. A GSL-containing lipid-raft model of P. aeruginosa host cell binding/internalization is proposed
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Affiliation(s)
- Aufaugh Emam
- Molecular Structure and Function, The Research Institute, Hospital for Sick Children, Toronto, Ontario M5G 1X8, Canada
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Abstract
PURPOSE To identify the pathophysiological changes produced by contact lens wear that predispose the cornea to infection and search for prospective modifiable risk factors that could reduce the incidence of this critical complication in millions of patients worldwide. METHODS Significant experimental and clinical publications are reviewed, and the results of ongoing studies are presented. RESULTS Pseudomonas aeruginosa (PA) is the most common pathogen causing lens-related infectious keratitis over 3 decades. Contact lens wear can increase the risk of infection by increasing surface cell PA binding, thereby promoting invasion between broken tight junctions and initiating direct intracellular invasion mediated by lens-induced membrane lipid rafts. Prevention of upregulation of specific surface-binding receptors for PA with concomitant increase in infection risk is a zero damage game where independent interactions among lens type, mode of wear, oxygen transmissibility, polymer, and toxic effects of associated care solutions ideally should collectively produce no increased ability for PA to attach and/or to invade, thus minimizing the risk for lens-associated infections. The specific hypothesis tested is, "no increased epithelial surface damage... no increased PA binding or invasion... no increased risk for infection." Testing of this new paradigm has been performed in vitro and in animal and human clinical trials and correlated clinically with relative risk results from robust current epidemiological studies. Results to date clearly support the use of lens-related increases in PA binding (bench) as a noninvasive clinical predictor of risk for lens-related infection in subsequent large-scale population studies (bedside). Currently, results suggest that use of common commercial multipurpose lens care solutions with soft lenses may alone significantly increase infection risk by enhancing lens-related PA binding as compared with use of nonpreserved solutions (hydrogen peroxide). Clinical testing also shows that only peroxide solutions show significant disinfection capability against amoebic cysts. Further case-control studies to examine relative risk for infection by lens type and lens care solution are urgently needed. CONCLUSIONS Millions of patients are dependent on contact lenses for vision worldwide; over 3 decades, lens use has increased, although risk for lens-related infection has remained stubbornly unchanged. Unfortunately, recent introduction of a new generation of hyper-oxygen transmissible lenses used with traditional multipurpose lens care solutions has not lowered overall risks for lens-related infections; however, similar lenses used with nonpreserved care solutions (peroxide) recently demonstrated no significant increases in PA binding in a 1-year clinical trial. Collectively, these findings along with the urgent need for amoebic cysticidal disinfection have led to a current recommendation to patients to use nonpreserved (hydrogen peroxide) care solutions in soft lens wear.
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Sun Y, Karmakar M, Roy S, Ramadan RT, Williams SR, Howell S, Shive CL, Han Y, Stopford CM, Rietsch A, Pearlman E. TLR4 and TLR5 on corneal macrophages regulate Pseudomonas aeruginosa keratitis by signaling through MyD88-dependent and -independent pathways. THE JOURNAL OF IMMUNOLOGY 2010; 185:4272-83. [PMID: 20826748 DOI: 10.4049/jimmunol.1000874] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Pseudomonas aeruginosa is a major cause of blindness and visual impairment in the United States and worldwide. Using a murine model of keratitis in which abraded corneas are infected with P. aeruginosa parent and ΔfliC (aflagellar) strains 19660 and PAO1, we found that F4/80(+) macrophages were the predominant cell type in the cornea expressing TLR2, TLR4, and TLR5. Depletion of macrophages and dendritic cells using transgenic Mafia mice, in which Fas ligand is selectively activated in these cells, resulted in diminished cytokine production and cellular infiltration to the corneal stroma and unimpaired bacterial growth. TLR4(-/-) mice showed a similar phenotype postinfection with ΔfliC strains, whereas TLR4/5(-/-) mice were susceptible to corneal infection with parent strains. Bone marrow-derived macrophages stimulated with ΔfliC bacteria induced Toll/IL-1R intracellular domain (TIR)-containing adaptor inducing IFN-β (TRIF)-dependent phosphorylation of IFN regulatory factor 3 in addition to TIR-containing adaptor protein/MyD88-dependent phosphorylation of IκB and nuclear translocation of the p65 subunit of NFκB. Furthermore, TRIF(-/-) mice showed a similar phenotype as TLR4(-/-) mice in regulating only ΔfliC bacteria, whereas MyD88(-/-) mice were unable to clear parent or ΔfliC bacteria. Finally, IL-1R1(-/-) and IL-1α/β(-/-) mice were highly susceptible to infection. Taken together, these findings indicate that P. aeruginosa activates TLR4/5 on resident corneal macrophages, which signal through TRIF and TIR-containing adaptor protein/MyD88 pathways, leading to NF-κB translocation to the nucleus, transcription of CXCL1 and other CXC chemokines, recruitment of neutrophils to the corneal stroma, and subsequent bacterial killing and tissue damage. IL-1α and IL-1β are also produced, which activate an IL-1R1/MyD88-positive feedback loop in macrophages and IL-1R on other resident cells in the cornea.
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Affiliation(s)
- Yan Sun
- Department of Ophthalmology and Visual Sciences, Case Western Reserve University, Cleveland, OH 44106, USA
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Xu Y, Krause A, Hamai H, Harvey BG, Worgall TS, Worgall S. Proinflammatory phenotype and increased caveolin-1 in alveolar macrophages with silenced CFTR mRNA. PLoS One 2010; 5:e11004. [PMID: 20543983 PMCID: PMC2882373 DOI: 10.1371/journal.pone.0011004] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2010] [Accepted: 05/15/2010] [Indexed: 11/18/2022] Open
Abstract
The inflammatory milieu in the respiratory tract in cystic fibrosis (CF) has been linked to the defective expression of the cystic transmembrane regulator (CFTR) in epithelial cells. Alveolar macrophages (AM), important contibutors to inflammatory responses in the lung, also express CFTR. The present study analyzes the phenotype of human AM with silenced CFTR. Expression of CFTR mRNA and the immature form of the CFTR protein decreased 100-fold and 5.2-fold, respectively, in AM transfected with a CFTR specific siRNA (CFTR-siRNA) compared to controls. Reduction of CFTR expression in AM resulted in increased secretion of IL-8, increased phosphorylation of NF-κB, a positive regulator of IL-8 expression, and decreased expression of IκB-α, the inhibitory protein of NF-κB activation. AM with silenced CFTR expression also showed increased apoptosis. We hypothesized that caveolin-1 (Cav1), a membrane protein that is co-localized with CFTR in lipid rafts and that is related to inflammation and apoptosis in macrophages, may be affected by decreased CFTR expression. Messenger RNA and protein levels of Cav1 were increased in AM with silenced CFTR. Expression and transcriptional activity of sterol regulatory element binding protein (SREBP), a negative transcriptional regulator of Cav1, was decreased in AM with silenced CFTR, but total and free cholesterol mass did not change. These findings indicate that silencing of CFTR in human AM results in an inflammatory phenotype and apoptosis, which is associated to SREBP-mediated regulation of Cav1.
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Affiliation(s)
- Yaqin Xu
- Department of Pediatrics, Weill Cornell Medical College, New York, New York, United States of America
| | - Anja Krause
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Hiroko Hamai
- Department of Pathology, Columbia University, New York, New York, United States of America
| | - Ben-Gary Harvey
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
| | - Tilla S. Worgall
- Department of Pathology, Columbia University, New York, New York, United States of America
| | - Stefan Worgall
- Department of Pediatrics, Weill Cornell Medical College, New York, New York, United States of America
- Department of Genetic Medicine, Weill Cornell Medical College, New York, New York, United States of America
- * E-mail:
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Bodas M, Vij N. The NF-kappaB signaling in cystic fibrosis lung disease: pathophysiology and therapeutic potential. DISCOVERY MEDICINE 2010; 9:346-356. [PMID: 20423679 PMCID: PMC3114405] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Lung disease is the major cause of morbidity and mortality of cystic fibrosis (CF), an autosomal recessive disease caused by mutations in CF transmembrane-conductance regulator (CFTR) gene. In CF, elevated levels of interleukin-8 (IL-8) signaling mediated by the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kappaB) result in chronic infection, neutrophilic inflammation, and progressive airway destruction. The most frequent mutation in the CFTR gene is the deletion of phenylalanine 508 (DeltaF508), which results in its endoplasmic reticulum associated degradation (ERAD) by the ubiquitin-proteasome system. The inability of DeltaF508-CFTR to reach cell surface leads to inherently high levels of NF-kappaB. Severity of CF lung disease depends on the levels of functional CFTR on cell surface that control its chloride transport and NF-kappaB mediated innate immune response functions. NF-kappaB mediated chronic inflammation is a prominent feature of CF lung disease and the mechanism(s) by which CFTR regulates these inflammatory signaling pathways is becoming apparent. Recent data suggest that CFTR localization to lipid-rafts is critical for regulating NF-kappaB mediated innate immune response and chronic CF lung disease. We anticipate that targeting the pathways, which facilitates CFTR's rescue to the cell surface and lipid-rafts, will not only restore CFTR channel function but also control NF-kappaB mediated chronic inflammation, although the level of correction may be a critical factor for therapeutic efficacy. We discuss here the mechanisms of NF-kappaB induction in CF, pathogenesis of CF lung disease, and novel therapeutic strategies that may help in reversing the chronic CF lung disease.
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Affiliation(s)
- Manish Bodas
- Department of Pediatrics Division of Pulmonary Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
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Zeitlin PL. Pseudomonas aeruginosa: can studies in engineered cells tell us why is it such a problem in people with cystic fibrosis? Focus on “Cystic fibrosis transmembrane conductance regulator and caveolin-1 regulate epithelial cell internalization of Pseudomonas aeruginosa”. Am J Physiol Cell Physiol 2009; 297:C235-7. [DOI: 10.1152/ajpcell.00257.2009] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Grassmé H, Becker KA, Zhang Y, Gulbins E. Ceramide in bacterial infections and cystic fibrosis. Biol Chem 2008; 389:1371-9. [PMID: 18783339 DOI: 10.1515/bc.2008.162] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Ceramide is formed by the activity of sphingomyelinases, by degradation of complex sphingolipids, reverse ceramidase activity or de novo synthesized. The formation of ceramide within biological membranes results in the formation of large ceramide-enriched membrane domains. These domains serve the spatial and temporal organization of receptors and signaling molecules. The acid sphingomyelinase-ceramide system plays an important role in the infection of mammalian host cells with bacterial pathogens such as Neisseria gonorrhoeae, Escherichia coli, Staphylococcus aureus, Listeria monocytogenes, Salmonella typhimurium and Pseudomonas aeruginosa. Ceramide and ceramide-enriched membrane platforms are also involved in the induction of apoptosis in infected cells, such as in epithelial and endothelial cells after infection with Pseudomonas aeruginosa and Staphylococcus aureus, respectively. Finally, ceramide-enriched membrane platforms are critical regulators of the release of pro-inflammatory cytokines upon infection. The diverse functions of ceramide in bacterial infections suggest that ceramide and ceramide-enriched membrane domains are key players in host responses to many pathogens and thus are potential novel targets to treat infections.
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Affiliation(s)
- Heike Grassmé
- Department of Molecular Biology, University of Duisburg-Essen, Hufelandstrasse 55, D-45122 Essen, Germany
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