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Ian F Pitha, Amanda Chow, Liam McCrea, Julia Szeto, Elizabeth Kimball, Julie Schaub, Harry A Quigley; The multikinase inhibitor dasatinib inhibits scleral myofibroblast differentiation. Invest. Ophthalmol. Vis. Sci. 2019;60(9):6474. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
Scleral myofibroblasts increase in mouse models of glaucoma and myopia. The purpose of these studies was to identify kinase inhibitors that reduce myofibroblast differentiation and could potentially modify diseases of scleral remodeling.
Two low-passage human peripapillary fibroblast cell lines were screened with a library of 80 kinase inhibitors to identify molecules that inhibit TGFb-induced myofibroblast differentiation. Myofibroblast differentiation was determined by alpha-actin-2 (ACTA2) immunoblot and collagen contraction assay. Scleral fibroblast proliferation was assessed by ELISA assay for proliferating cell nuclear antigen (PCNA) following IOP elevation by anterior chamber bead injection and subconjunctival injection of dasatinib.
Five compounds in the library were strong hits (>70% reduction without toxicity, 1 µM dosage) in each cell line (PP1, PP2, tyrphostin 9, rottlerin, SU4312) and all but one of these compounds (SU4312) reduced TGFb-induced ACTA2 expression and collagen contraction. Two compounds were Src family kinase inhibitors (PP1 and PP2). These compounds have potential cross reactivity for the TGFb receptor, therefore, additional compounds were used to investigate the relationship between SRC inhibition and myofibroblast differentiation. Src family kinase inhibitors dasatinib, bosutinib, and SU-6656 (1µM) inhibited TGFb-induced myofibroblast collagen plug contraction 60% (p<0.0001), 1% (p=0.35), and 24% (p=0.005), respectively. Bosutinib and SU-6656 inhibited TGFb- and LPA-induced myofibroblast differentiation at micromolar dosages. Dasatinib, however, reduced TGFb- and LPA-induced ACTA2 expression at nanomolar dosages and scleral fibroblast proliferation (100 nM dosage, 94% reduction, p<0.0001) following IOP elevation. In addition, dasatinib did not affect TGFb-induced SMAD2/3 phosphorylation at nanomolar dosages.
The kinase inhibitor dasatinib reduced TGFb- and LPA-induced myofibroblast differentiation and glaucoma-induced scleral cell proliferation. This activity is not associated with altered canonical TGFb signaling and is likely not due solely to SRC inhibition because other SRC family inhibitors did not show similar activity.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
Reduced TGFb-induced extracellular matrix production (signal) by scleral fibroblasts following dasatinib treatment
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