Therapeutic potential of non‐viral MRNA delivery to Müller cells for neuroprotection

• Published in: Acta ophthalmologica (Oxford, England) Vol. 94; no. S256
• Main Authors: Devoldere, J., Peynshaert, K., De Smedt, S., Remaut, K.
• Format: Journal Article
• Language: English
• Published: Malden Wiley Subscription Services, Inc 01-10-2016
• Subjects: Chemical modification; Formulations; Gene expression; Green fluorescent protein; mRNA; Mutation; Neuroprotection; Ophthalmology; Retina; Retinal cells; Retinal degeneration; RNA modification; Toxicity; Transfection; Vision
• ISSN: 1755-375X; 1755-3768
• DOI: 10.1111/j.1755-3768.2016.0366

Purpose
Retinal cell degeneration is a leading cause of vision loss in many ocular diseases. The progressive loss of retinal cells is often hereditary, but rarely monogenic. This enormous diversity in disease‐inducing mutations has hampered the development of gene replacement strategies to prevent or reverse retinal degeneration. Therefore interest has augmented for a treatment strategy that halts the degeneration process, rather than correcting the initial causative mutation. This work aims to evaluate the potential of chemically modified mRNA as a therapeutic strategy to stimulate neuronal survival and save vision, regardless of the initial genetic defect.
Methods
Evaluation of mRNA delivery to Müller cells was conducted in MIO‐M1 cells, using modified and unmodified reporter mRNA encoding the Green Fluorescent Protein (GFP). Lipid‐based vectors carrying the mRNA were delivered to Müller cells via serum‐containing medium or injected into fresh bovine vitreous, applied on top of the cells. In both setups uptake, level and duration of eGFP expression and toxicity of the lipoplex formulations were evaluated. In addition, the suitability of these complexes for intravitreal injection was assessed by measuring their mobility in bovine vitreous on a single‐particle level.
Results
Overall transfection levels are decreased in presence of vitreous, indicating that the vitreous is an important barrier for non‐viral mRNA delivery to the retina. Chemical modification of the mRNA substantially increased eGFP expression in >80% of cultured Müller cells.
Conclusions
Our data demonstrate that non‐viral lipid based carriers show good potential to transfect Müller cells in vitro. However, to make these mRNA therapeutics suitable for ocular targets, development of strategies to overcome the vitreal barrier will be crucial to implement ocular mRNA therapy in the future.