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 (AAVs). While LNPs can transfect outer retinal cells, their tropism for inner retinal cell types remains insufficiently characterized. Here, we systematically assessed cellular tropism of conventional LNPs encapsulating chemically modified mRNA encoding mCherry in murine retinal explants and dissociated retinal cells. 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 Muller 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 significantly 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-associated barriers significantly 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 versatile tool for mRNA delivery to the retina, with applications in gene supplementation, gene editing, and regenerative therapies for inner retinal disorders.