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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...

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Autores principales: Sun, Yi-Chen, Hung, Kai-Feng, Li, Tzu-Yun, Chang, Yu-An, Yeh, Po-Ting, Hu, Fung-Rong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Association for Research in Vision and Ophthalmology 2022
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.
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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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