Dataset Information

Vitamin D enhances corneal epithelial barrier function.

ABSTRACT:

Purpose

The purpose of this study was to determine whether 25-hydroxyvitamin D(3) (25(OH)D(3)) and/or its active metabolite, 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), can enhance corneal epithelial barrier function. The authors also determined if corneas contain mRNA for the vitamin D receptor (VDR) and 1α-hydroxylase, the enzyme required to convert 25(OH)D(3) to 1,25(OH)(2)D(3), and measured vitamin D metabolite concentrations in aqueous and vitreous humor.

Methods

RT-PCR was used to examine mouse, rabbit, and human corneal epithelial VDR and 1α-hydroxylase mRNA. Vitamin D metabolites were measured using a selective vitamin D derivatizing agent and mass spectroscopy. Barrier function experiments were performed by measuring inulin permeability (IP) and/or transepithelial resistance (TER) in control, 25(OH)D(3)-, and 1,25(OH)(2)D(3)-treated human and rabbit corneal epithelial monolayers cultured on permeable inserts. Ca(2+) was removed, then reintroduced to the culture medium while IP and TER readings were taken. Occludin levels were examined using Western blotting.

Results

All corneal samples were positive for both VDR and 1α-hydroxylase mRNA. All vitamin D metabolites except for unhydroxylated vitamin D(3) were detected in aqueous and vitreous humor. Epithelial cells showed increased TER, decreased IP, and increased occludin levels when cultured with 25(OH)D(3) and 1,25(OH)(2)D(3).

Conclusions

We conclude that corneas contain mRNA for VDR and 1α-hydroxylase as well as significant vitamin D concentrations. 25(OH)D(3) and its active metabolite 1,25(OH)(2)D(3), both enhance corneal epithelial barrier function.

SUBMITTER: Yin Z

PROVIDER: S-EPMC3183972 | biostudies-literature | 2011 Sep

REPOSITORIES: biostudies-literature

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Publications

Vitamin D enhances corneal epithelial barrier function.

Yin Zhaohong Z Pintea Victorina V Lin Yanping Y Hammock Bruce D BD Watsky Mitchell A MA

Investigative ophthalmology & visual science 20110921 10

<h4>Purpose</h4>The purpose of this study was to determine whether 25-hydroxyvitamin D(3) (25(OH)D(3)) and/or its active metabolite, 1α,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), can enhance corneal epithelial barrier function. The authors also determined if corneas contain mRNA for the vitamin D receptor (VDR) and 1α-hydroxylase, the enzyme required to convert 25(OH)D(3) to 1,25(OH)(2)D(3), and measured vitamin D metabolite concentrations in aqueous and vitreous humor.<h4>Methods</h4>RT-PCR wa ...[more]

PMID: 21715350

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Project description:PurposeTo investigate the impact of transmembrane protein CMTM6 on the pathogenesis of dry eye disease (DED) and elucidate its potential mechanisms.MethodsCMTM6 expression was confirmed by database analysis, real-time polymerase chain reaction (RT-PCR), western blot, and immunohistochemistry. Tear secretion was measured using the phenol red thread test. Immune cell infiltration was assessed through flow cytometry. Barrier function was evaluated by fluorescein sodium staining, immunofluorescence staining of zonula occludens 1 (ZO-1), and electric cell-substrate impedance sensing (ECIS) assessment. For silencing CMTM6 expression, siRNA and shRNA were employed, along with lentiviral vector-mediated overexpression of CMTM6. Proinflammatory cytokine levels were analyzed by RT-PCR and cytometric bead array (CBA) analysis.ResultsCMTM6 showed high expression in healthy human and mouse corneal and conjunctival epithelium but was notably reduced in DED. Notably, this downregulation was correlated with disease severity. Cmtm6-/- dry eye (DE) mice displayed reduced tear secretion, severe corneal epithelial defects, decreased conjunctival goblet cell density, and upregulated inflammatory response. Additionally, Cmtm6-/- DE mice and CMTM6 knockdown human corneal epithelial cell-transformed (HCE-T) cells showed more severe barrier disruption and reduced expression of ZO-1. Knockdown of CMTM6 in HCE-T cells increased inflammatory responses induced by hyperosmotic stress, which was significantly mitigated by CMTM6 overexpression. Moreover, the level of phospho-p65 in hyperosmolarity-stimulated HCE-T cells increased after silencing CMTM6. Nuclear factor kappa B (NF-κB) p65 inhibition (JSH-23) reversed the excessive inflammatory responses caused by hyperosmolarity in CMTM6 knockdown HCE-T cells.ConclusionsThe reduction in CMTM6 expression on the ocular surface contributes to the pathogenesis of DED. The CMTM6-NF-κB p65 signaling pathway may serve as a promising therapeutic target for DED.

Dataset Information

Vitamin D enhances corneal epithelial barrier function.

Purpose

Methods

Results

Conclusions

Publications

Vitamin D enhances corneal epithelial barrier function.

Similar Datasets

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