Purchase this article with an account.
Ratnakar Tripathi, Lynn M. Martin, Sabeeh Kamil, Nishant Rajiv Sinha, Alexandria Hofmann, Sydney Green, Praveen Balne, Suneel Gupta, Prashant R. Sinha, Nathan Hesemann, Frederick W Fraunfelder, Shyam S Chaurasia, Rajiv R Mohan; SIRT1: A novel target to regulate corneal myofibroblast formation. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2605.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Corneal scarring/fibrosis is common after trauma, infection, or refractive surgery in the eye. Our recent studies revealed that histone deacetylase (HDAC) inhibitors, Trichostatin-A, SAHA, and ITF2357, inhibit corneal fibrosis in vivo. We hypothesized that class III HDAC, sirtuins are involved in corneal wound healing and fibrosis regulation. The aims of the study were to (1) characterize levels and localization of SIRT1 mRNA and protein in the cornea, and (2) study its role in corneal wound healing modulation.
Donor human corneas and naive/wounded corneas of New Zealand White rabbits collected at different times were used. The qRT-PCR, Immunofluorescence, and immunoblotting techniques were employed to measure the level and localization of gene and protein in cell cultures and corneal tissues. Primary human corneal stromal fibroblasts (hCSF) were grown in the presence and absence of TGFβ1 (5ng/ml) at different time points (0, 12, 24, 48, and 72 hours) for time-dependent experiments aimed to analyze SIRT1 mRNA and protein expression. Gene transfer gain-of-function and loss-of-function experiments were also explored, involving nanoparticles delivered SIRT1 overexpression and siRNA mediated gene silencing.
Normal human and rabbit corneas showed SIRT1 expression in the epithelium, stroma, and endothelium. A significantly (p<0.001) decreased levels of SIRT1 were observed in wounded human and rabbit corneas. hCSFs exposed to TGFβ1 demonstrated decreased SIRT1 mRNA (p<0.001) and protein (p<0.001) levels in a time-dependent manner. Gene transfer gain-of-function shows significant (p<0.01) decreased level of αSMA (key regulator of fibrosis) and siRNA driven gene silencing shows significant (p<0.01) increase in αSMA in vitro. Gain-of-function and loss of function experiments involving SIRT1 overexpression and gene silencing demonstrated regulation of the TGFβ1-mediated wound healing process by SIRT1 in an in vitro model of corneal fibrosis.
To the best of our knowledge, this is the first report to show the expression of SIRT1 in the cornea and its role in TGFβ1 driven corneal fibrosis. More studies are underway.
This is a 2020 ARVO Annual Meeting abstract.
This PDF is available to Subscribers Only