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Transforming growth factor β1-induced NADPH Oxidase-4 expression and fibrotic response in conjunctival fibroblasts


Brown, KD and Shah, MH and Liu, G-S and Chan, E and Crowston, JG and Peshavariya, HM, Transforming growth factor β1-induced NADPH Oxidase-4 expression and fibrotic response in conjunctival fibroblasts, Investigative Ophthalmology & Visual Science, 58, (7) pp. 3011-3017. ISSN 1552-5783 (2017) [Refereed Article]


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Copyright 2017 The Authors. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

DOI: doi:10.1167/iovs.16-20633


Purpose: Fibrotic scarring after ocular surgeries and chemical burn injuries can impede clarity of the cornea and cause vision impairment. Transforming growth factor β (TGFβ) signaling pathway is known to mediate fibrotic scarring, and NADPH oxidase-derived reactive oxygen species has been shown to be an effector molecule that facilitates TGFβ1-mediated responses. The present study explores the expression profile and functional importance of NADPH oxidase (Nox) in conjunctival fibroblasts. In addition, the effect of curcumin on the TGFβ1-induced NADPH oxidase expression and collagen synthesis was also investigated.

Methods: The mRNA expression of Nox isoforms in rabbit conjunctival fibroblasts was measured by real-time PCR. The production of hydrogen peroxide (H2O2) and total collagen by these cells was measured by Amplex Red assay and Picro-Sirius red assay, respectively. Nox4 was knocked down by adenovirus-mediated siRNA targeting Nox4 (Adv-Nox4i).

Results: We describe for the first time that conjunctival fibroblasts express mRNA encoding for Nox2, Nox3, Nox4, and Nox5. TGFβ1 was found to induce Nox4 mRNA expression and total collagen release by these cells (P < 0.05; n = 4), and both responses are blocked by Smad3 inhibitor SIS3. Suppressing Nox4 gene transcription with Adv-Nox4i completely attenuated TGFβ1-stimulated H2O2 release and collagen production by conjunctival fibroblasts (P < 0.05; n = 4-6). Similarly, curcumin also inhibited TGFβ1-induced Smad3 phosphorylation, Nox4-derived H2O2 production, and total collagen synthesis by conjunctival fibroblasts (P < 0.05; n = 4-6).

Conclusions: The present study suggests that TGFβ1-mediated production of collagen by conjunctival fibroblasts involves Nox4-derived H2O2 pathway and this effect of Nox4 is abrogated by curcumin. This mechanism might be exploited to prevent fibrotic scarring after surgeries and chemical burn injuries in the eye.

Item Details

Item Type:Refereed Article
Keywords:conjunctiva, Nox4, TGFb1, curcumin, ocular fibrosis
Research Division:Biomedical and Clinical Sciences
Research Group:Ophthalmology and optometry
Research Field:Ophthalmology
Objective Division:Health
Objective Group:Clinical health
Objective Field:Clinical health not elsewhere classified
UTAS Author:Liu, G-S (Associate Professor Guei-Sheung Liu)
ID Code:123379
Year Published:2017
Web of Science® Times Cited:17
Deposited By:Menzies Institute for Medical Research
Deposited On:2018-01-03
Last Modified:2018-03-07
Downloads:123 View Download Statistics

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