The use of synthetic RNA for research purposes as well as RNA-based therapy and vaccination has gained increasing importance. Given the anatomical seclusion of the eye, small interfering RNA (siRNA)-induced gene silencing bears great potential for targeted reduction of pathological gene expression that may allow rational treatment of chronic eye diseases in the future. However, there is yet an unmet need for techniques providing safe and efficient siRNA delivery to the retina. We used magnetic nanoparticles (MNPs) and magnetic force (Reverse Magnetofection) to deliver siRNA/MNP complexes into retinal explant tissue, targeting valosin-containing protein (VCP) previously established as a potential therapeutic target for autosomal dominant retinitis pigmentosa (adRP). Safe and efficient delivery of VCP siRNA was achieved into all retinal cell layers of retinal explants from the RHO P23H rat, a rodent model for adRP. No toxicity or microglial activation was observed. VCP silencing led to a significant decrease of retinal degeneration. Reverse Magnetofection thus offers an effective method to deliver siRNA into retinal tissue. Used in combination with retinal organotypic explants, it can provide an efficient and reliable preclinical test platform of RNA-based therapy approaches for ocular diseases.

Background. Traumatic brain injury (TBI) is the main cause of disabilities over the industrialized countries. Cognitive decline appears in the chronic phase of the pathology consecutively to cellular and molecular processes. Here we described the use of KCC2, a neuronal-specific potassium-chloride transporters as potent biomarker to predict cognitive dysfunctions after TBI. Methods. Using neuronal and total exosomes collection from blood serum in control and TBI subjects we were able to anticipate the decline of cognitive performance. Results. After TBI, we observed a significative and persistant loss of KCC2 expression in the blood exosomes that is correlated to changes in network activity and cellular processes such as secondary neurogenesis. Also we correlated this KCC2 loss in expression to the appearance of the cognitive decline observed in mice and more particularly we correlate the KCC2 loss of expression to the appearance of the depressive-like behavior. Conclusion. According to our protocol, we were able to confirm our previous findings in agreement with the potential therapeutic effect of bumetanide in the prevention of the post traumatic depression after TBI, by restoring the KCC2 expression thus preventing the massive neuronal death of interneurons and the secondary neurogenesis effect observed in such model.