Factors Impacting Corneal Epithelial Barrier Function against<i>Pseudomonas aeruginosa</i>Traversal

Alarcon, I.; Tam, Connie; Mun, Jeomhee; LeDue, Jeffrey; Evans, David J.; Fleiszig, Suzanne M. J.

doi:10.1167/iovs.10-6125

Cited by 74 publications

(97 citation statements)

References 43 publications

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“…2,3 Disruption of corneal epithelial barrier function results in ocular irritation 4,5 and increased risk for microbial infections. 6 The electrophysical properties of a cell or tissue can be determined by passing an electric current through the cell or tissue and measuring the voltage drop and potential difference across the tissue. When the current delivered and the voltage measured are known, the resistance of the tissue can be calculated using Ohm's Law: resistance (Ω) is equal to the voltage (V) divided by the current (I in amperes).…”

Section: Introduction Introductionmentioning

confidence: 99%

Less Invasive Corneal Transepithelial Electrical Resistance Measurement Method

et al. 2016

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Purpose: To evaluate acute corneal permeability changes after instillation of benzalkonium chloride (BAC) using a newly developed in vivo less invasive corneal TER measurement method in animals and humans. Methods: We previously developed an in vivo method for measuring corneal transepithelial electrical resistance (TER) using intraocular electrodes in animals. This method can be used to precisely measure the decline of the corneal barrier function after instillation of BAC. To lessen the invasiveness of that procedure, we further refined the method for measuring the corneal TER by developing electrodes that could be placed on the surface of the cornea and in the conjunctival sac instead of inserting them into the anterior chamber. Corneal TER changes before and after exposure to 0.02% BAC were determined in this study using the new device in both rabbits and humans. Results: There was a significant decrease in the corneal TER after exposure of the cornea to 0.02% BAC solution in both rabbits and humans (P.01). The results of this new less invasive method agreed with those of formerly established anterior chamber methods as regards rabbits experiment and was expected and satisfactory as regards human experiment.Conclusion: This new less invasive corneal TER measurement method enables us for the first time to measure TER of the human cornea, allowing safe and reliable investigation of the direct effect of different eye drops treatments on the corneal epithelium.

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confidence: 99%

Less Invasive Corneal Transepithelial Electrical Resistance Measurement Method

et al. 2016

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“…More recently, we developed a suite of in vivo and ex vivo models to allow early steps in pathogenesis to be studied, requiring no or minimal injury to the epithelium (46,47). We have also advanced our imaging methods and analysis software to allow accurate localization/quantification of all bacteria in corneas of live eyeballs, without need for fixation or sectioning (47).…”

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“…We showed that blotting the corneal surface with tissue paper (Kimwipe), which disrupts tight junctions while otherwise leaving corneas morphologically similar, made corneas susceptible to bacterial adhesion without subsequent epithelial traversal. When blotting was followed by 1 h of EGTA treatment (100 mM in phosphate-buffered saline [PBS]), the bacteria could traverse the epithelium all the way to the underlying basal lamina (46). Using gene knockout mice, we have found that MyD88 is important for protecting the corneal epithelium against both adhesion and subsequent traversal (47) and that mBD3, the mouse equivalent of human hBD2 and a MyD88-dependent factor (51,52), is involved in this protective effect (49).…”

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“…Here, we examined the role of ExsA in invasive P. aeruginosa traversal of the corneal epithelium using these new models of superficial injury (blotting plus EGTA) and immunocompromise (MyD88 Ϫ/Ϫ ), which both make the epithelium permissive to traversal while retaining the basal lamina barrier (46,47), and outcomes were assessed using our new imaging methods (47). This was done using PAO1, an invasive strain that traverses the corneal epithelium to the level of the basal lamina in both models, and ex vivo conditions to exclude direct effects of tear fluid, blinking, and other extracorneal factors during bacterial inoculation (46,47).…”

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“…This was done using PAO1, an invasive strain that traverses the corneal epithelium to the level of the basal lamina in both models, and ex vivo conditions to exclude direct effects of tear fluid, blinking, and other extracorneal factors during bacterial inoculation (46,47).…”

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The Importance of the Pseudomonas aeruginosa Type III Secretion System in Epithelium Traversal Depends upon Conditions of Host Susceptibility

et al. 2015

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Pseudomonas aeruginosa is invasive or cytotoxic to host cells, depending on the type III secretion system (T3SS) effectors encoded. While the T3SS is known to be involved in disease in vivo, how it participates remains to be clarified. Here, mouse models of superficial epithelial injury (tissue paper blotting with EGTA treatment) and immunocompromise (MyD88 deficiency) were used to study the contribution of the T3SS transcriptional activator ExsA to epithelial traversal. Corneas of excised eyeballs were inoculated with green fluorescent protein (GFP)-expressing PAO1 or isogenic exsA mutants for 6 h ex vivo before bacterial traversal and epithelial thickness were quantified by using imaging. In the blotting-EGTA model, exsA mutants were defective in capacity for traversal. Accordingly, an ϳ16-fold variability in exsA expression among PAO1 isolates from three sources correlated with epithelial loss. In contrast, MyD88؊/؊ epithelia remained susceptible to P. aeruginosa traversal despite exsA mutation. Epithelial lysates from MyD88 ؊/؊ mice had reduced antimicrobial activity compared to those from wild-type mice with and without prior antigen challenge, particularly 30-to 100-kDa fractions, for which mass spectrometry revealed multiple differences, including (i) lower baseline levels of histones, tubulin, and lumican and (ii) reduced glutathione S-transferase, annexin, and dermatopontin, after antigen challenge. Thus, the importance of ExsA in epithelial traversal by invasive P. aeruginosa depends on the compromise enabling susceptibility, suggesting that strategies for preventing infection will need to extend beyond targeting the T3SS. The data also highlight the importance of mimicking conditions allowing susceptibility in animal models and the need to monitor variability among bacterial isolates from different sources, even for the same strain. P seudomonas aeruginosa remains a leading cause of respiratory infections, septicemia, and urinary tract and burn wound infections (1-4). It is also the most common cause of corneal infection associated with contact lens wear (5, 6). Our research has shown that clinical and laboratory isolates of P. aeruginosa can be divided into invasive or cytotoxic strains based upon how they interact with host cells (7). Invasive strains can survive and replicate inside epithelial cells dependent on the type III secretion system (T3SS) effector ExoS (8-10), while cytotoxic strains instead encode ExoU, which can induce rapid death of intoxicated host cells (11,12). While details of how invasive and cytotoxic strains impact host cells vary, both types can cause human disease, and they can each be virulent in animal models of infection (13-15).Several in vivo models exist for studying P. aeruginosa pathogenicity. They include Caenorhabditis elegans (16-18) and Drosophila melanogaster (19), in addition to mouse models of pneumonia with sepsis (20-22), burn wound infection with sepsis (23-25), and gastrointestinal colonization and sepsis (26,27) and corneal scarification models (28)(29)(30)...

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IL‐17 plays a central role in initiating experimental Candida albicans infection in mouse corneas

Zou

et al. 2013

Eur J Immunol

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The pathogenesis of fungal infection in the cornea remains largely unclear. To understand how the immune system influences the progression of fungal infection in corneas, we inoculated immunocompetent BALB/c mice, neutrophil-or CD4+ T-cell-depleted BALB/c mice, and nude mice with Candida albicans. We found that only immunocompetent BALB/c mice developed typical Candida keratitis (CaK), while the other mouse strains lacked obvious clinical manifestations. Furthermore, CaK development was blocked in immunocompetent mice treated with anti-IL-17A or anti-IL-23p19 to neutralize IL-17 activity. However, no significant effects were observed when Treg cells, γδ T cells, or IFN-γ were immunodepleted. Upon infection, the corneas of BALB/c mice were infiltrated with IL-17-producing leukocytes, including neutrophils and, to a lesser degree, CD4 + T cells.In contrast, leukocyte recruitment to corneas was significantly diminished in nude mice. Indeed, nude mice produced much less chemokines (e.g. CXCL1, CXCL2, CXCL10, CXCL12, CCL2, and IL-6) in response to inoculation. Remarkably, addition of CXCL2 during inoculation restored CaK induction in nude mice. In contrast to its therapeutic effect on CaK, neutralization of IL-17 exacerbated Candida-induced dermatitis in skin. We conclude that IL-17, mainly produced by neutrophils and CD4 + T cells in the corneas, is essential in the pathogenesis of CaK. Keywords: Candida albicans · Corneal infection · Fungal infection · IL-17 · NeutrophilAdditional supporting information may be found in the online version of this article at the publisher's web-site IntroductionFungal infection of the cornea, namely fungal keratitis (FK), is among the main causes of blindness in many parts of the world. While the causative pathogens differ by geographic region, the most prevalent genera are Fusarium, Aspergillus, and Candida [1][2][3]. The structural characteristics of cornea (i.e. thinness and transparency) and the high proliferation rate of most initiated Correspondence: Dr. Yiqiang Wang e-mail: yiqiangwang99@hotmail.com fungi contribute to the rapid onset of FK and total loss of sight within a few days of infection. Unfortunately, many aspects of FK pathogenicity remain unclear. For example, it is not known whether the avascularity of the cornea, which affords immune and lymphangiogenic "privilege", is responsible for the rapid progression of FK [4,5]. FK progresses even after leukocytes, including neutrophils and lymphocytes, infiltrate infected cornea.Although well-documented in other organs, studies on the host-pathogen interactions in the context of FK are lacking [4][5][6]. The available data suggest an innate immune response plays a vital role in the response to fungal infection of the cornea [7,8]. Eur. J. Immunol. 2013Immunol. . 43: 2671Immunol. -2682 Figure 1. Innate resistance of nude mice to CaK induction. BALB/c mice and nude mice were inoculated with 1 × 10 5 Candida albicans blastospores. (A) The corneas were monitored under a slit lamp, and (B) evaluated with the scoring system. D...

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Factors Impacting Corneal Epithelial Barrier Function againstPseudomonas aeruginosaTraversal

Cited by 74 publications

References 43 publications

Less Invasive Corneal Transepithelial Electrical Resistance Measurement Method

Less Invasive Corneal Transepithelial Electrical Resistance Measurement Method

The Importance of the Pseudomonas aeruginosa Type III Secretion System in Epithelium Traversal Depends upon Conditions of Host Susceptibility

IL‐17 plays a central role in initiating experimental Candida albicans infection in mouse corneas

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