Contributions of MyD88-dependent receptors and CD11c-positive cells to corneal epithelial barrier function against Pseudomonas aeruginosa

Metruccio, Matteo M. E.; Tam, Connie; Evans, David J.; Xie, Anna; Stern, Michael E.; Fleiszig, Suzanne M. J.

doi:10.1038/s41598-017-14243-w

Cited by 21 publications

(52 citation statements)

References 49 publications

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“…It is possible that we had missed the peak time point for the induction of IL-18, as we focused on the effect of acute stimulation. As previously reported, we confirmed the induction of TNF-␣ and CXCL-1 by P. aeruginosa (35,36,47). Our results showed that both P. aeruginosa LPS and flagellin contributed to the induction of IL-1␤, IL-6, TNF-␣, and CXCL-1.…”

Section: Discussionsupporting

confidence: 92%

Pseudomonas aeruginosa Stimulates Inflammation and Enhances Kaposi’s Sarcoma Herpesvirus-Induced Cell Proliferation and Cellular Transformation through both Lipopolysaccharide and Flagellin

Markazi

Bracci

McGrath³

et al. 2020

mBio

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Inflammation triggered by innate immunity promotes carcinogenesis in cancer. Kaposi’s sarcoma (KS), a hyperproliferative and inflammatory tumor caused by Kaposi’s sarcoma-associated herpesvirus (KSHV) infection, is the most common cancer in AIDS patients. KSHV infection sensitizes cells to pathogen-associated molecular patterns (PAMPs). We examined the role of Pseudomonas aeruginosa, an opportunistic bacterium that can affect AIDS patients, in inflammation and cell proliferation of KSHV-transformed cells. P. aeruginosa stimulation increased cell proliferation and efficiency of colony formation in soft agar of KSHV-transformed rat primary mesenchymal precursor (KMM) cells but had no significant effect on the untransformed (MM) cells. P. aeruginosa stimulation also increased cell proliferation of KSHV-infected human B cells, BJAB, but not the uninfected cells. Mechanistically, P. aeruginosa stimulation resulted in increased inflammatory cytokines and activation of p38, ERK1/2, and JNK mitogen-activated protein kinase (MAPK) pathways in KMM cells while having no obvious effect on MM cells. P. aeruginosa induction of inflammation and MAPKs was observed with and without inhibition of the Toll-like receptor 4 (TLR4) pathway, while a flagellin-deleted mutant of P. aeruginosa required a functional TLR4 pathway to induce inflammation and MAPKs. Furthermore, treatment with either lipopolysaccharide (LPS) or flagellin alone was sufficient to induce inflammatory cytokines, activate MAPKs, and increase cell proliferation and efficiency of colony formation in soft agar of KMM cells. These results demonstrate that both LPS and flagellin are PAMPs that contribute to P. aeruginosa induction of inflammation in KSHV-transformed cells. Because AIDS-KS patients are susceptible to P. aeruginosa infection, our work highlights the preventive and therapeutic potential of targeting P. aeruginosa infection in these patients. IMPORTANCE Kaposi’s sarcoma (KS), caused by infection with Kaposi’s sarcoma-associated herpesvirus (KSHV), is one of the most common cancers in AIDS patients. KS is a highly inflammatory tumor, but how KSHV infection induces inflammation remains unclear. We have previously shown that KSHV infection upregulates Toll-like receptor 4 (TLR4), sensitizing cells to lipopolysaccharide (LPS) and Escherichia coli. In the current study, we examined the role of Pseudomonas aeruginosa, an opportunistic bacterium that can affect AIDS patients, in inflammation and cell proliferation of KSHV-transformed cells. P. aeruginosa stimulation increased cell proliferation, inflammatory cytokines, and activation of growth and survival pathways in KSHV-transformed cells through two pathogen-associated molecular patterns, LPS and flagellin. Because AIDS-KS patients are susceptible to P. aeruginosa infection, our work highlights the preventive and therapeutic potential of targeting P. aeruginosa infection in these patients.

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Section: Discussionsupporting

confidence: 92%

Pseudomonas aeruginosa Stimulates Inflammation and Enhances Kaposi’s Sarcoma Herpesvirus-Induced Cell Proliferation and Cellular Transformation through both Lipopolysaccharide and Flagellin

Markazi

Bracci

McGrath³

et al. 2020

mBio

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show abstract

“…It is possible that we had missed the peak time point for the induction of IL-18 as we focused on the effect of acute stimulation. As previously reported, we confirmed the induction of TNF-α and CXCL-1 by PA (35,36,47). Our results showed that both PA LPS and flagellin contributed to the induction of IL-1β, IL-6, TNF-α, and CXCL-1.…”

Section: Discussionsupporting

confidence: 92%

Pseudomonas aeruginosa Stimulates Inflammation and Enhances KSHV-Induced Cell Proliferation and Cellular Transformation through Both LPS and Flagellin

Markazi

Bracci²,

McGrath³

et al. 2020

Preprint

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Inflammation triggered by innate immunity promotes carcinogenesis in cancer. Kaposi’s sarcoma (KS), a hyperproliferative and inflammatory tumor caused by Kaposi’s sarcoma-associated herpesvirus (KSHV) infection, is the most common cancer in AIDS patients. KSHV infection sensitizes cells to pathogen-associated molecular patterns (PAMPs). We examined the role of Pseudomonas aeruginosa (PA), an opportunistic bacterium that can affect AIDS patients, in inflammation and cell proliferation of KSHV-transformed cells. PA stimulation increased cell proliferation and efficiency of colony formation in softagar of KSHV-transformed rat primary mesenchymal precursor (KMM) cells but had no significant effect on the untransformed (MM) cells. PA stimulation also increased cell proliferation of KSHV-infected human B-cells, Bjab, but not the uninfected cells. Mechanistically, PA stimulation resulted in increased inflammatory cytokines and activation of p38, ERK1/2, and JNK mitogen-activated protein kinase (MAPK) pathways in KMM cells while having no obvious effect on MM cells. PA induction of inflammation and MAPKs were observed with and without inhibition of Toll-like receptor 4 (TLR4) pathway while a flagellin-deleted mutant of PA required a functional TLR4 pathway to induce inflammation and MAPKs. Furthermore, treatment with both LPS or flagellin alone was sufficient to induce inflammatory cytokines, activate MAPKs, and increase cell proliferation and efficiency of colony formation in softagar of KMM cells. These results demonstrate that both LPS and flagellin are PAMPs that contribute to PA induction of inflammation in KSHV-transformed cells. Because AIDS-KS patients are susceptible to PA infection, our work highlights the preventive and therapeutic potential of targeting PA infection in these patients.ImportanceKaposi’s sarcoma (KS), caused by infection of Kaposi’s sarcoma-associated herpesvirus (KSHV), is one of the most common cancers in AIDS patients. KS is a highly inflammatory tumor but how KSHV infection induces inflammation remains unclear. We have previously shown that KSHV infection upregulates Toll-like receptor 4 (TLR4), sensitizing cells to lipopolysaccharide (LPS) and Escherichia coli. In the current study, we examined the role of Pseudomonas aeruginosa (PA), an opportunistic bacterium that can affect AIDS patients, in inflammation and cell proliferation of KSHV-transformed cells. PA stimulation increased cell proliferation, inflammatory cytokines, and activation of growth and survival pathways in KSHV-transformed cells through two pathogen-associated molecular patterns LPS and flagellin. Because AIDS-KS patients are susceptible to PA infection, our work highlights the preventive and therapeutic potential of targeting PA infection in these patients.

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“…Dendritic cells, which can be distinguished by their expression of CD11c, are known to be sentinel cells in mucosae and epithelia [49–51]. Indeed, we previously showed that CD11c-positive cells play important roles in early recognition of, and response to, P. aeruginosa at the ocular surface at 4 h [43]. Thus, we investigated CD11c-positive cell responses to contact lens wear using mice expressing YFP under control of the CD11c promoter.…”

Section: Resultsmentioning

confidence: 99%

“…Using reagents available for mice but not humans, we additionally show that uninoculated contact lens wear can induce parainflammation consisting of neutrophil recruitment in otherwise healthy-appearing corneas. This phenomenon was found dependent on MyD88 and IL-1R, well known for their role in host innate defense, and as we have previously shown, regulate multiple relevant phenomena in the healthy cornea including its lack of a viable bacterial microbiome, its glycosylation, and epithelial defenses against microbial adhesion and penetration [40,42,43]. This model allows us to further our understanding of lens-associated events at the ocular surface, and their role in susceptibility to infection.…”

Section: Introductionmentioning

confidence: 95%

A novel murine model for contact lens wear reveals clandestine IL-1R dependent corneal parainflammation and susceptibility to microbial keratitis upon inoculation with Pseudomonas aeruginosa

et al. 2019

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Purpose Contact lens wear carries a risk of complications, including corneal infection. Solving these complications has been hindered by limitations of existing animal models. Here, we report development of a new murine model of contact lens wear. Methods C57BL/6 mice were fitted with custom-made silicone-hydrogel contact lenses with or without prior inoculation with Pseudomonas aeruginosa (PAO1-GFP). Contralateral eyes served as controls. Corneas were monitored for pathology, and examined ex vivo using high-magnification, time-lapse imaging. Fluorescent reporter mice allowed visualization of host cell membranes and immune cells. Lens-colonizing bacteria were detected by viable counts and FISH. Direct-colony PCR was used for bacterial identification. Results Without deliberate inoculation, lens-wearing corneas remained free of visible pathology, and retained a clarity similar to non-lens wearing controls. CD11c-YFP reporter mice revealed altered numbers, and distribution, of CD11c-positive cells in lens-wearing corneas after 24 h. Worn lenses showed bacterial colonization, primarily by known conjunctival or skin commensals. Corneal epithelial cells showed vacuolization during lens wear, and after 5 days, cells with phagocyte morphology appeared in the stroma that actively migrated over resident keratocytes that showed altered morphology. Immunofluorescence confirmed stromal Ly6G-positive cells after 5 days of lens wear, but not in MyD88 or IL-1R gene-knockout mice. P. aeruginosa-contaminated lenses caused infectious pathology in most mice from 1 to 13 days. Conclusions This murine model of contact lens wear appears to faithfully mimic events occurring during human lens wear, and could be valuable for experiments, not possible in humans, that help solve the pathogenesis of lens-related complications.

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Contributions of MyD88-dependent receptors and CD11c-positive cells to corneal epithelial barrier function against Pseudomonas aeruginosa

Cited by 21 publications

References 49 publications

Pseudomonas aeruginosa Stimulates Inflammation and Enhances Kaposi’s Sarcoma Herpesvirus-Induced Cell Proliferation and Cellular Transformation through both Lipopolysaccharide and Flagellin

Pseudomonas aeruginosa Stimulates Inflammation and Enhances Kaposi’s Sarcoma Herpesvirus-Induced Cell Proliferation and Cellular Transformation through both Lipopolysaccharide and Flagellin

Pseudomonas aeruginosa Stimulates Inflammation and Enhances KSHV-Induced Cell Proliferation and Cellular Transformation through Both LPS and Flagellin

A novel murine model for contact lens wear reveals clandestine IL-1R dependent corneal parainflammation and susceptibility to microbial keratitis upon inoculation with Pseudomonas aeruginosa

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