Abstract
Purpose: :
Expression of prostaglandin F2α (PGF2α) biosynthesis and response pathway component transgenes from integrated transgenes in the anterior chamber of the eye has been shown to reduce intraocular pressure (IOP) and hence represents a candidate gene therapy for glaucoma. Founding work used multiple lentiviral vectors to express individual protein components of the PGF2α pathway. A single vector that consolidates components would facilitate clinical grade and clinical scale lentiviral production and its application to glaucoma.
Methods: :
A one vector system (1VS) was generated that encodes codon-optimized mRNAs for COX-2 (coCOX-2) and the FP receptor (coFPR) from a bidirectional promoter. This vector was first compared to a previously published efficacious two-vector system (2VS) in vitro for expression level, cellular localization, and biological activity of the PG system proteins. The single vector, the established two-vector system, or a GFP-expressing control vector were also injected into the anterior chambers of domestic cats in order to transduce the trabecular meshwork, which regulates aqueous humor outflow.
Results: :
1VS-transduced cells expressed both transgenes and confocal microscopy confirmed appropriate intracellular localization. Production of PGF2α was robust using both the 1VS and 2VS. A transcriptional reporter assay for coFPR activity revealed 1VS signaling 8.5-fold higher than 2VS. In vivo in the cat, an accessible and affordable mammal with a large, primate-similar anterior chamber that has been instrumental for validating glaucoma pharmacologics, both vector systems were effective at lowering IOP over the 4-month study period, and were not significantly different in hypotensive effect.
Conclusions: :
A single lentiviral vector gene therapy was effective in expressing PG pathway components and mediated sustained IOP reduction in vivo.
Keywords: eicosanoids • gene transfer/gene therapy • intraocular pressure