Lipid nanoparticles enable mRNA delivery to diverse cell types of the inner Retina

Lipid nanoparticles (LNPs) have emerged as a promising platform for retinal genetic therapy, offering a non-viral alternative to adeno-associated viruses. Although LNPs can transfect outer retinal cells, their transfection profile across inner retinal cell types remains insufficiently characterized. Here, we systematically assessed the cell-type transfection profile of conventional LNPs encapsulating chemically modified mRNA encoding mCherry in murine retinal explants, complemented by experiments in dissociated retinal cell cultures. We compared quasi-subretinal and quasi-intravitreal administrations and evaluated how retinal degeneration and inner limiting membrane (ILM) integrity influence LNP-mediated transfections. We observed that LNPs efficiently transfected Müller glia under all experimental conditions. In addition, LNPs transfected several other retinal cell types, including neurons in dissociated cells and explants, and vascular cells exclusively in explants. Subretinal delivery resulted in higher transfection rates than intravitreal administration, and overall efficiency was higher in degenerate as compared to non-degenerate healthy retinas. In healthy retinas, removal of ILM increased transfection efficiency following intravitreal administration. Together, these findings demonstrate that conventional LNPs can transfect a broader range of retinal cell types than previously recognized and highlight LNPs as a tool for mRNA delivery to the retina, with applications in gene supplementation, editing, and regenerative therapies for inner retinal disorders.