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Audrey M Bernstein, Nileyma Castro Davila, Andrew Phillips, Edward Francis Boumil; Targeting p53 and integrins to prevent corneal scarring. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2606.
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After wounding there is an initial phase of cellular apoptosis followed by an influx of immune cells with the development of pathological myofibroblasts in the later stages of healing. We propose that the deubiquitinase (DUB), USP10 modulates the initial phase of apoptosis through the deubiquitination of p53, and the later phase of myofibroblast persistence through the deubiquitination of av integrins. In this study we demonstrate that targeting USP10 prevents corneal scarring through modulation of these two pathways.
Twelve New Zealand White, female rabbits were treated with control self-delivery siRNA (sdRNA) or with USP10-sdRNA. The corneas were wounded with a 6mm trephine prior to treatment with sdRNAs (6 per group). On days 1,2,3 or 6 weeks unwounded and wounded corneas were excised and immunostained for TUNEL and CD45 (days 1,2,3) or Collagen III, Fibronectin (FN)-EDA, α-SMA (6 weeks). Matrix recycling assay with biotinylated FN and live cell confocal. Ubiquitin assay by ELISA. Significance: One-way ANOVA with Bonferroni’s test or Student’s t-test.
USP10 shuttles between the nucleus and cytoplasm. After wounding, p53 is deubiquitinated by USP10, protecting it from degradation and inducing pro-apoptotic signaling. Correspondingly, 1-3 days after wounding, sdUSP10 treatment reduced apoptosis (83.3%, p<0.001) and CD45+ infiltration (46.3%, p<0.05) in rabbit corneas. At 6 weeks post-wounding, when scars are formed, sdUSP10 decreased Col III (71.7%), FN-EDA (53.8%), and α-SMA (83.6%); p<0.05. Mechanistically, in myofibroblasts USP10 deubiquitinates αv integrins leading to an increase in integrin cell surface accumulation. We now report that the USP10-integrin axis in myofibroblasts is controlled by its binding partners, the formin Daam1 (repressive) and the recycling endosomal marker, G3BP2 (activating). Daam1 knockdown yielded an average 75% decrease in ubiquitination of αv integrins, p<0.01 reducing integrin degradation and a 2.6-fold increase in integrin-mediated FN recycling (p<0.05), whereas G3BP2 knockdown had the opposite effect. We hypothesize that reducing apoptosis and subsequent inflammation and increasing integrin degradation in infiltrating myofibroblasts yields an anti-fibrotic effect.
USP10 and its regulators are novel targets at the intersection of apoptosis and integrin activity. Self-delivery siRNA to USP10 after corneal wounding is a new method to prevent scarring.
This is a 2020 ARVO Annual Meeting abstract.
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