Biology subjects

FISSON, S.

Publications and source records attributed to FISSON, S..

3 recordsLinked to original sources

bioRxiv2025

Inter-individual variability in immune responses to AAV-mediated ocular gene delivery across species impedes reliable immunomonitoring profile

Adeno-associated viruses (AAVs) have been used in gene therapy, especially for inherited retinal diseases. Despite their effectiveness in gene transduction, immune responses to the AAV capsid and transgene products have been reported, which can compromise both the efficacy and safety of AAV-mediated therapies. The eye is regarded as an immune-privileged organ where immune activity is constitutively suppressed. Here, we highlight that immunomonitoring in an ocular gene transfer reveals variable immune responses, whatever the species (human clinical trial, non-human primates, mice), the site of injection, the cassette, and the dose. We further explored factors contributing to this variability, investigating the correlation among immune parameters in a controlled experimental setting. In a syngeneic murine model after an intraocular injection of AAV, our results highlight an inter-individual variability of immune parameters, emphasizing the importance of considering inherent variability among individuals while designing personalized therapies.

immunology↗

bioRxiv2023

Direct delivery of Cas9 or base editor protein and guide RNA complex enables genome editing in the retina

Genome editing by CRISPR-Cas holds promise for the treatment of retinal dystrophies. For therapeutic gene editing, transient delivery of CRISPR- Cas9 is preferable to viral delivery which leads to long-term expression with potential adverse consequences. Successful delivery of Cas9 protein and its guide RNA as ribonucleoprotein (RNP) complexes has been reported in the retinal pigment epithelium in vivo but not into photoreceptors, the main target of retinal dystrophies. Here, we investigate the feasibility of direct RNP delivery to photoreceptors and RPE cells. We show that RNPs composed of Cas9 or adenine- base editor and guide RNA, without addition of any carrier compounds, induce gene editing in retinal cells at variable rates depending on the guide RNA efficiency and on the locus. But Cas9 RNP delivery at high concentrations leads to outer retinal toxicity indicating a need to improve delivery efficiency for future therapeutic use.

bioengineering↗

bioRxiv2023

Cellular Immune Responses Induced by Subretinal AAV Gene Transfer can be Restrained by the Subretinal Associated Immune Inhibition Mechanism

For more than a decade, AAV-mediated gene transfer has been tested successfully in clinical trials to treat inherited retinal diseases. Despite the eyes immune-privileged status and the use of corticoids as an adjunct treatment, some patients display inflammatory events which led us to question the immune consequences of a subretinal AAV administration. We first characterized anti-transgene immune responses induced in the periphery by injecting increasing doses of AAV8 encoding reporter proteins fused with the HY male antigen into the subretinal space of female C57BL/6 and rd10 mice. Transgene expression was monitored over time with bioluminescence imaging and T-cell immune responses in the spleen were analyzed by IFN{gamma} ELISpot and cytokine multiplex assays. Our data show that an AAV8 injection causes proinflammatory T-cell immune response against the transgene product, correlated with the transgene expression level at 2.109 vg and above. Additionally, co-injection of immunodominant peptides from the transgene product, along with AAV8, modulates the immune response at all AAV doses tested. Taken together, our data suggest that injection of AAV8 in the subretinal space induces proinflammatory peripheral T-cell responses to the transgene product that can be modulated by the subretinal associated immune inhibition (SRAII) mechanism.

immunology↗