Abstract
Purpose :
Current glaucoma medications rely on decreasing IOP by administering topical eye drops which have a long list of drawbacks such as poor compliance and inadequate application. Consequently, there is a strong need for new therapeutic concepts to prevent vision loss. In the present study, we have identified CD44 as a potential target receptor for nanoparticle (NP) delivery in trabecular meshwork (TM) and Schlemm canal (SC) cells. We developed hyaluronan (HA) coated-NP (HA-NPs) with the intention to target the CD44 receptor and to deliver siRNAs to outflow pathway cells.
Methods :
CD44 expression was analyzed in TM cells after treatment with TGF-β2 (1ng/ml) and CTGF (50ng/ml), in eyes of the bB1-CTGF glaucoma mouse model, in SC cells as well as outflow tissues derived from glaucomatous and healthy donor eyes by RT-qPCR, Western Blot and/or immunohistochemistry (IHC). LBL-coated NPs were assembled in a modular approach. The particles have four layers: siRNA layer is sandwiched between two polycationic layers, followed by a final layer based on HA. Porcine and human perfusion models were used to deliver NPs coated with HA or polyethylene imine (PEI-NPs) and IHC was performed to investigate NP distribution. Transfection efficiency of PEI-NPs and HA-NPs were analyzed in TM cells by silencing CTGF with a specific siRNA. Statistical analyses were performed with Student ‘s t-test.
Results :
CD44 expression was significantly increased after TGF-β2 (2.2±0.4) and CTGF (3.8±0.7) treatment in TM cells and in outflow tissues of CTGF overexpression mice in comparison to controls. Elevated CD44 expression was detected in SC cells and in outflow tissues of eyes from glaucomatous donors compared to healthy eyes. The uptake of HA-NPs was 3-fold more efficient (p£0.05) in TM cells compared to PEI-NPs. In porcine and human perfusion model, HA-NPs were found in a higher concentration within the outflow tissue than PEI-NPs. IHC analyses showed a clustering of PEI-NPs in the corneoscleral TM, whereas HA-NPs were found throughout the entire outflow tissues. SiRNA delivery and silencing of CTGF were significantly efficient with HA-NPs (0.5±0.1; p£0.05), PEI-NPs had no effect (0.9±0.2).
Conclusions :
We have identified CD44 as a promising target receptor to deliver NPs to the outflow pathway tissue. We suggest that HA-NPs are an excellent therapeutic approach to deliver specific agents to the outflow tissues.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.