IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine Cornea
Microbial communities are important for the health of mucosal tissues. Traditional culture and gene sequencing have demonstrated bacterial populations on the conjunctiva. However, it remains unclear if the cornea, a transparent tissue critical for vision, also hosts a microbiome. Corneas of wild-typ...
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Frontiers Media S.A.
2018-05-01
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| Series: | Frontiers in Microbiology |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fmicb.2018.01117/full |
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doaj-e93a9bd13a0c43ec95d25bc6cb1157122020-11-24T22:44:24ZengFrontiers Media S.A.Frontiers in Microbiology1664-302X2018-05-01910.3389/fmicb.2018.01117372958IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine CorneaStephanie J. Wan0Aaron B. Sullivan1Peyton Shieh2Matteo M. E. Metruccio3David J. Evans4David J. Evans5Carolyn R. Bertozzi6Carolyn R. Bertozzi7Carolyn R. Bertozzi8Suzanne M. J. Fleiszig9Suzanne M. J. Fleiszig10Vision Science Program, University of California, Berkeley, Berkeley, CA, United StatesSchool of Optometry, University of California, Berkeley, Berkeley, CA, United StatesCollege of Chemistry, University of California, Berkeley, Berkeley, CA, United StatesSchool of Optometry, University of California, Berkeley, Berkeley, CA, United StatesSchool of Optometry, University of California, Berkeley, Berkeley, CA, United StatesCollege of Pharmacy, Touro University California, Vallejo, CA, United StatesSchool of Optometry, University of California, Berkeley, Berkeley, CA, United StatesDepartment of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, United StatesHoward Hughes Medical Institute, University of California, Berkeley, Berkeley, CA, United StatesSchool of Optometry, University of California, Berkeley, Berkeley, CA, United StatesGraduate Groups in Vision Sciences, Microbiology, and Infectious Diseases & Immunity, University of California, Berkeley, Berkeley, CA, United StatesMicrobial communities are important for the health of mucosal tissues. Traditional culture and gene sequencing have demonstrated bacterial populations on the conjunctiva. However, it remains unclear if the cornea, a transparent tissue critical for vision, also hosts a microbiome. Corneas of wild-type, IL-1R (-/-) and MyD88 (-/-) C57BL/6 mice were imaged after labeling with alkyne-functionalized D-alanine (alkDala), a probe that only incorporates into the peptidoglycan of metabolically active bacteria. Fluorescence in situ hybridization (FISH) was also used to detect viable bacteria. AlkDala labeling was rarely observed on healthy corneas. In contrast, adjacent conjunctivae harbored filamentous alkDala-positive forms, that also labeled with DMN-Tre, a Corynebacterineae-specific probe. FISH confirmed the absence of viable bacteria on healthy corneas, which also cleared deliberately inoculated bacteria within 24 h. Differing from wild-type, both IL-1R (-/-) and MyD88 (-/-) corneas harbored numerous alkDala-labeled bacteria, a result abrogated by topical antibiotics. IL-1R (-/-) corneas were impermeable to fluorescein suggesting that bacterial colonization did not reflect decreased epithelial integrity. Thus, in contrast to the conjunctiva and other mucosal surfaces, healthy murine corneas host very few viable bacteria, and this constitutive state requires the IL-1R and MyD88. While this study cannot exclude the presence of fungi, viruses, or non-viable or dormant bacteria, the data suggest that healthy murine corneas do not host a resident viable bacterial community, or microbiome, the absence of which could have important implications for understanding the homeostasis of this tissue.https://www.frontiersin.org/article/10.3389/fmicb.2018.01117/fullbacteriamicrobiomemurine corneaAlkDalaDMN-TreIL-1R |
| collection |
DOAJ |
| language |
English |
| format |
Article |
| sources |
DOAJ |
| author |
Stephanie J. Wan Aaron B. Sullivan Peyton Shieh Matteo M. E. Metruccio David J. Evans David J. Evans Carolyn R. Bertozzi Carolyn R. Bertozzi Carolyn R. Bertozzi Suzanne M. J. Fleiszig Suzanne M. J. Fleiszig |
| spellingShingle |
Stephanie J. Wan Aaron B. Sullivan Peyton Shieh Matteo M. E. Metruccio David J. Evans David J. Evans Carolyn R. Bertozzi Carolyn R. Bertozzi Carolyn R. Bertozzi Suzanne M. J. Fleiszig Suzanne M. J. Fleiszig IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine Cornea Frontiers in Microbiology bacteria microbiome murine cornea AlkDala DMN-Tre IL-1R |
| author_facet |
Stephanie J. Wan Aaron B. Sullivan Peyton Shieh Matteo M. E. Metruccio David J. Evans David J. Evans Carolyn R. Bertozzi Carolyn R. Bertozzi Carolyn R. Bertozzi Suzanne M. J. Fleiszig Suzanne M. J. Fleiszig |
| author_sort |
Stephanie J. Wan |
| title |
IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine Cornea |
| title_short |
IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine Cornea |
| title_full |
IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine Cornea |
| title_fullStr |
IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine Cornea |
| title_full_unstemmed |
IL-1R and MyD88 Contribute to the Absence of a Bacterial Microbiome on the Healthy Murine Cornea |
| title_sort |
il-1r and myd88 contribute to the absence of a bacterial microbiome on the healthy murine cornea |
| publisher |
Frontiers Media S.A. |
| series |
Frontiers in Microbiology |
| issn |
1664-302X |
| publishDate |
2018-05-01 |
| description |
Microbial communities are important for the health of mucosal tissues. Traditional culture and gene sequencing have demonstrated bacterial populations on the conjunctiva. However, it remains unclear if the cornea, a transparent tissue critical for vision, also hosts a microbiome. Corneas of wild-type, IL-1R (-/-) and MyD88 (-/-) C57BL/6 mice were imaged after labeling with alkyne-functionalized D-alanine (alkDala), a probe that only incorporates into the peptidoglycan of metabolically active bacteria. Fluorescence in situ hybridization (FISH) was also used to detect viable bacteria. AlkDala labeling was rarely observed on healthy corneas. In contrast, adjacent conjunctivae harbored filamentous alkDala-positive forms, that also labeled with DMN-Tre, a Corynebacterineae-specific probe. FISH confirmed the absence of viable bacteria on healthy corneas, which also cleared deliberately inoculated bacteria within 24 h. Differing from wild-type, both IL-1R (-/-) and MyD88 (-/-) corneas harbored numerous alkDala-labeled bacteria, a result abrogated by topical antibiotics. IL-1R (-/-) corneas were impermeable to fluorescein suggesting that bacterial colonization did not reflect decreased epithelial integrity. Thus, in contrast to the conjunctiva and other mucosal surfaces, healthy murine corneas host very few viable bacteria, and this constitutive state requires the IL-1R and MyD88. While this study cannot exclude the presence of fungi, viruses, or non-viable or dormant bacteria, the data suggest that healthy murine corneas do not host a resident viable bacterial community, or microbiome, the absence of which could have important implications for understanding the homeostasis of this tissue. |
| topic |
bacteria microbiome murine cornea AlkDala DMN-Tre IL-1R |
| url |
https://www.frontiersin.org/article/10.3389/fmicb.2018.01117/full |
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