May 2008
Volume 49, Issue 13
Free
ARVO Annual Meeting Abstract  |   May 2008
Pharmaological Control of Angiofibrosis by Withaferin A
Author Affiliations & Notes
  • R. Mohan
    Ophthalmology and Visual Science, University of Kentucky, Lexington, Kentucky
  • E. Alimova
    Ophthalmology and Visual Science, University of Kentucky, Lexington, Kentucky
  • B. Trucchi
    Ophthalmology and Visual Science, University of Kentucky, Lexington, Kentucky
  • P. Bargagna-Mohan
    Ophthalmology and Visual Science, University of Kentucky, Lexington, Kentucky
  • Footnotes
    Commercial Relationships  R. Mohan, patent pending, P; E. Alimova, None; B. Trucchi, None; P. Bargagna-Mohan, Patent Pending, P.
  • Footnotes
    Support  NIH Grant EY0167821
Investigative Ophthalmology & Visual Science May 2008, Vol.49, 1487. doi:https://doi.org/
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    • Get Citation

      R. Mohan, E. Alimova, B. Trucchi, P. Bargagna-Mohan; Pharmaological Control of Angiofibrosis by Withaferin A. Invest. Ophthalmol. Vis. Sci. 2008;49(13):1487. doi: https://doi.org/.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: : We previously showed that the angiogenesis inhibitor withaferin A (WFA) downregulates injury-induced protein polyubiquitination in the inflammatory model of corneal neovascularization. We also discovered that WFA’s anti-angiogenic activity is mediated by direct binding to the intermediate filament (IF) protein vimentin (Bargagna-Mohan et al., Chemistry & Biology, 2007). Here, we have investigated the vimentin-targeting activity of WFA on the ubiquitin proteasome pathway in this model.

Methods: : Corneal neovascularization was induced by application of 0.15 M sodium hydroxide to mouse corneas followed by deepithelialization of epithelium from limbus to central cornea. 129/Svev vimentin-deficient (vim-/-) and wild-type mice subjected to this injury were treated with vehicle or WFA (2 mg/kg/d). At different times post injury, mice were killed and total proteins from corneal tissues was isolated and subjected to western blotting. Additionally, cryo-sections of eyes were stained with antibodies to ubiquitin, vimentin, desmin and α-smooth muscle (α-sm) actin.

Results: : WFA downregulates the injury-induced expression of polyubiquitinated proteins in a time- and dose-dependent manner. Desmin expression in injured corneas was upregulated and localized to invasive blood vessels and WFA treatment downregulated its expression. In vim-/- mice compared to wild-type mice, desmin expression was surprisingly reduced and correlated also with the low expression of α-sm actin. The injury-induced high expression of polyubiquitinated proteins was comparable between vim-/- and wild-type mice, however WFA treatment did not reduce injury-induced expression of polyubiquitinated proteins in vim-/- mice.

Conclusions: : WFA exerts its anti-angiogenic activity through vimentin and causes downregulation of expression of polyubiquitinated proteins and fibrotic markers such as α-sm actin and desmin. WFA’s pharmacological control of this angiofibrotic axis in vimentin deficiency is severely attenuated. These findings unveil vimentin-targeting as a novel mechanism to control the diseased upregulation of protein ubiquitination. WFA's potent in vivo activities suggest that this withanolide could be exploited as a drug lead in development of therapeutics to control angiofibrosis.

Keywords: cytoskeleton • protein modifications-post translational • receptors: pharmacology/physiology 
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