Real-Time Monitoring of Exosome Enveloped-AAV Spreading by Endomicroscopy Approach: A New Tool for Gene Delivery in the Brain

Nicola Salvatore Orefice (1, 2) , Benoît Souchet (1, 2) , Jérôme Braudeau (1, 2) , Sandro Alves (1, 2) , Françoise Piguet (1, 2) , Fanny Collaud (3) , Giuseppe Ronzitti (3) , Satoru Tada (1, 2) , Philippe Hantraye (2, 4) , Federico Mingozzi (4, 3) , Frederic Duconge (2, 4) , Nathalie Cartier (1, 2)

1 U 1169 - Thérapie génique, Génomique et Epigénomique
2 MIRCEN - Molecular Imaging Research Center [Fontenay-aux-Roses]
3 INTEGRARE - Approches génétiques intégrées et nouvelles thérapies pour les maladies rares
4 LMN - Laboratoire des Maladies Neurodégénératives - UMR 9199

Exosomes represent a strategy for optimizing the adeno-associated virus (AAV) toward the development of novel therapeutic options for neurodegenerative disorders. However, in vivo spreading of exosomes and AAVs after intracerebral administration is poorly understood. This study provides an assessment and comparison of the spreading into the brain of exosome-enveloped AAVs (exo-AAVs) or unassociated AAVs (std-AAVs) through in vivo optical imaging techniques like probe-based confocal laser endomicroscopy (pCLE) and ex vivo fluorescence microscopy. The std-AAV serotypes (AAV6 and AAV9) encoding the GFP were enveloped in exosomes and injected into the ipsilateral hippocampus. At 3 months post-injection, pCLE detected enhanced GFP expression of both exo-AAV serotypes in contralateral hemispheres compared to std-AAVs. Although sparse GFP-positive astro-cytes were observed using exo-AAVs, our results show that the enhancement of the transgene expression resulting from exo-AAVs was largely restricted to neurons and oligodendro-cytes. Our results suggest (1) the possibility of combining gene therapy with an endoscopic approach to enable tracking of exo-AAV spread, and (2) exo-AAVs allow for widespread, long-term gene expression in the CNS, supporting the use of exo-AAVs as an efficient gene delivery tool.

Domaines: Sciences du Vivant [q-bio]

Nicola Salvatore Orefice, Benoît Souchet, Jérôme Braudeau, Sandro Alves, Françoise Piguet, et al.. Real-Time Monitoring of Exosome Enveloped-AAV Spreading by Endomicroscopy Approach: A New Tool for Gene Delivery in the Brain. Molecular Therapy - Methods and Clinical Development, 2019, 14, pp.237 - 251. ⟨10.1016/j.omtm.2019.06.005⟩. ⟨cea-02997523⟩