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Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium
PURPOSE: To determine the role of transmembrane mucins in blocking fluorescein ingress to the corneal epithelium and its deficiency in contributing to corneal fluorescein punctate staining. METHODS: A dry eye model was established by extirpating lacrimal and Harderian glands in rabbits to correlate...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Association for Research in Vision and Ophthalmology
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8883176/ https://www.ncbi.nlm.nih.gov/pubmed/35212722 http://dx.doi.org/10.1167/iovs.63.2.31 |
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author | Sun, Yi-Chen Hung, Kai-Feng Li, Tzu-Yun Chang, Yu-An Yeh, Po-Ting Hu, Fung-Rong |
author_facet | Sun, Yi-Chen Hung, Kai-Feng Li, Tzu-Yun Chang, Yu-An Yeh, Po-Ting Hu, Fung-Rong |
author_sort | Sun, Yi-Chen |
collection | PubMed |
description | PURPOSE: To determine the role of transmembrane mucins in blocking fluorescein ingress to the corneal epithelium and its deficiency in contributing to corneal fluorescein punctate staining. METHODS: A dry eye model was established by extirpating lacrimal and Harderian glands in rabbits to correlate the expression of mucins with fluorescein-stained areas on the corneal button using immunofluorescence. Expression of transmembrane mucins was promoted in human corneal epithelial cells (HCECs) by culturing with the mucin-promoting medium (MPM) or diquafosol treatment. Conversely, the expression of mucins was downregulated by knockdown with short hairpin RNA. The role of mucin1 extracellular domain in fluorescein ingress was further verified by overexpression of N-terminally truncated mucin1 in HCECs. RESULTS: In the rabbit dry eye model, the expression level of mucin1 was significantly decreased in superficial corneal epithelial cells where fluorescein punctate staining was observed. Upregulation of mucin1 and mucin16 in HCECs promoted by MPM or by diquafosol treatment impeded intracellular fluorescein ingress. Downregulation of mucin1 and mucin16 enhanced fluorescence ingress in HCECs after fluorescein staining. Overexpression of truncated mucin1 did not alter the fluorescein intensity of fluorescein-stained HCECs, supporting the notion that the ability of mucin1 to block fluorescein ingress was primarily mediated by its extracellular domain. Minimal inherent expression of mucin16 in the rabbit cornea limited the validation of its role in blocking fluorescein ingress in vivo. CONCLUSION: Transmembrane mucin1 blocks fluorescein ingress in the corneal epithelium, explaining how fluorescein staining is positive when the level of transmembrane mucins is disturbed in dry eyes. |
format | Online Article Text |
id | pubmed-8883176 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | The Association for Research in Vision and Ophthalmology |
record_format | MEDLINE/PubMed |
spelling | pubmed-88831762022-03-01 Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium Sun, Yi-Chen Hung, Kai-Feng Li, Tzu-Yun Chang, Yu-An Yeh, Po-Ting Hu, Fung-Rong Invest Ophthalmol Vis Sci Cornea PURPOSE: To determine the role of transmembrane mucins in blocking fluorescein ingress to the corneal epithelium and its deficiency in contributing to corneal fluorescein punctate staining. METHODS: A dry eye model was established by extirpating lacrimal and Harderian glands in rabbits to correlate the expression of mucins with fluorescein-stained areas on the corneal button using immunofluorescence. Expression of transmembrane mucins was promoted in human corneal epithelial cells (HCECs) by culturing with the mucin-promoting medium (MPM) or diquafosol treatment. Conversely, the expression of mucins was downregulated by knockdown with short hairpin RNA. The role of mucin1 extracellular domain in fluorescein ingress was further verified by overexpression of N-terminally truncated mucin1 in HCECs. RESULTS: In the rabbit dry eye model, the expression level of mucin1 was significantly decreased in superficial corneal epithelial cells where fluorescein punctate staining was observed. Upregulation of mucin1 and mucin16 in HCECs promoted by MPM or by diquafosol treatment impeded intracellular fluorescein ingress. Downregulation of mucin1 and mucin16 enhanced fluorescence ingress in HCECs after fluorescein staining. Overexpression of truncated mucin1 did not alter the fluorescein intensity of fluorescein-stained HCECs, supporting the notion that the ability of mucin1 to block fluorescein ingress was primarily mediated by its extracellular domain. Minimal inherent expression of mucin16 in the rabbit cornea limited the validation of its role in blocking fluorescein ingress in vivo. CONCLUSION: Transmembrane mucin1 blocks fluorescein ingress in the corneal epithelium, explaining how fluorescein staining is positive when the level of transmembrane mucins is disturbed in dry eyes. The Association for Research in Vision and Ophthalmology 2022-02-25 /pmc/articles/PMC8883176/ /pubmed/35212722 http://dx.doi.org/10.1167/iovs.63.2.31 Text en Copyright 2022 The Authors https://creativecommons.org/licenses/by-nc-nd/4.0/This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. |
spellingShingle | Cornea Sun, Yi-Chen Hung, Kai-Feng Li, Tzu-Yun Chang, Yu-An Yeh, Po-Ting Hu, Fung-Rong Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium |
title | Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium |
title_full | Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium |
title_fullStr | Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium |
title_full_unstemmed | Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium |
title_short | Transmembrane Mucin 1 Blocks Fluorescein Ingress to Corneal Epithelium |
title_sort | transmembrane mucin 1 blocks fluorescein ingress to corneal epithelium |
topic | Cornea |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8883176/ https://www.ncbi.nlm.nih.gov/pubmed/35212722 http://dx.doi.org/10.1167/iovs.63.2.31 |
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