Carpentiero, E. | Search bioRxiv

bioRxiv2025

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.

neuroscience↗

bioRxiv2024

Interaction between native and prosthetic visual responses in optogenetic visual restoration

Degenerative retinal disorders leading to irreversible photoreceptor death are a common cause of blindness. Optogenetic gene therapy aims to restore vision in affected individuals by introducing light sensitive opsins into the surviving neurons of inner retina. While up until now the main focus of optogenetic therapy has been on terminally blind individuals, treating at stages where residual native vision is present could have several advantages. Yet, it is still unknown how residual native and optogenetic vision would interact if present at the same time. Using transgenic mice expressing the optogenetic tool ReaChR in ON-bipolar cells, we herein examine this interaction through electroretinography (ERG) and visually evoked potentials (VEP). We find that optogenetic responses show a peculiar ERG signature and are enhanced in retinas without photoreceptor loss. Conversely, native responses are dampened in the presence of ReaChR. Moreover, in VEP recordings we find that optogenetic responses reach the cortex asynchronous to the native response. These findings should be taken into consideration when planning future clinical trials and may direct future preclinical research to optimize optogenetic approaches for visual restoration. The identified ERG signatures moreover may serve to track treatment efficiency in clinical trials.

neuroscience↗