Expression of Dominant Negative K6W-Ubiquitin in the Lens Epithelium via an Adenoviral Vector Delays Posterior Capsule Opacification in a Rabbit Model

Curr Mol Med. 2017;17(2):160-168. doi: 10.2174/1566524017666170331163751.

Abstract

Purpose: Ubiquitin is involved in cell proliferation and differentiation, and the objective of this study is to investigate the potential of dominant negative Ubiquitin (Ub) with a lysine to tryptophan mutation at the 6 position (K6W) through an adenoviral expression vector in the prevention of posterior capsule opacification (PCO) in a rabbit PCO model.

Methods: Recombinant dominant negative K6W-Ub adenovirus (RAd-K6W-Ub) with green fluorescent protein (RAd-K6W-Ub/GFP) and RAd-GFP viruses (control) were generated with QBI-HEK 293A cells. New Zealand rabbits receiving lens phacoemulsification were given an intraoperative anterior chamber injection of the viruses. The images of anterior segment photography taken by a slit lamp biomicroscopy were analyzed by posterior capsule opacification manual software (POCOman) for PCO grading. The intraocular pressure (IOP) was detected with a non-contact tonometer (NCT). The expression of α-smooth muscle actin (α-SMA) was assessed by Western blotting. Cell migration ability in cultured rabbit's lens epithelial cells (LECs) was evaluated by scratch healing assay.

Results: The expression of GFP and Ub in the lens epithelium was markedly upregulated after 48 hours vector injection. Eyes injected with RAd-K6W-Ub showed a significantly lower PCO degree compared with controls. Meanwhile, higher IOP and corneal edema was observed in groups with a higher RAd-K6W-Ub virus dosage. The expression of α-SMA was down-regulated in the RAd-K6W-Ub eyes as compared to controls at the 15th day after injection. Cell migration was inhibited by RAd-K6W-Ub infection.

Conclusions: RAd-K6W-Ub at an appropriate dosage could inhibit the proliferation of LECs and the formation of PCO in rabbit models. However, a higher dosage of Rad- K6W-Ub viral vector caused toxic effects to the surrounding tissues, such as corneal edema and high IOP.

Keywords: K6W-ubiquitin; Posterior capsule opacification (PCO); adenoviral vector; lens epithelial cells (LECs); ubiquitin-proteasome pathway (UPP).

MeSH terms

  • Actins / genetics
  • Actins / metabolism
  • Adenoviridae* / genetics
  • Animals
  • Capsule Opacification / diagnosis
  • Capsule Opacification / genetics*
  • Capsule Opacification / metabolism*
  • Disease Models, Animal
  • Epithelial Cells / metabolism*
  • Epithelial Cells / pathology
  • Epithelial-Mesenchymal Transition / genetics
  • Gene Expression
  • Genetic Vectors / genetics*
  • Lens, Crystalline / cytology*
  • Mutation*
  • Proteasome Endopeptidase Complex / metabolism
  • Rabbits
  • Signal Transduction
  • Transduction, Genetic
  • Ubiquitin / genetics*
  • Ubiquitin / metabolism

Substances

  • Actins
  • Ubiquitin
  • Proteasome Endopeptidase Complex