Biology subjects

Fovet, C.-M.

Publications and source records attributed to Fovet, C.-M..

3 recordsLinked to original sources

bioRxiv2020

Optogenetic therapy: High spatiotemporal resolution and pattern recognition compatible with vision restoration in non-human primates

Restoring vision using optogenetics is an ideal medical application because the eye offers a direct window to access and stimulate the pathological area: the retina. Optogenetic therapy could be applied to diseases with photoreceptor degeneration such as retinitis pigmentosa. Here, we select the specific optogenetic construct that is now used in the clinical trial and assess the opsin functional efficacy on non-human primates retinal ganglion cells (RGCs). We chose the microbial opsin ChrimsonR and showed that the vector AAV2.7m8 produced greater transfection in RGCs compared to AAV2, and that ChrimsonR attached to tdTomato (ChR-tdT) is more efficiently expressed than ChrimsonR. The 600 nm light activates the RGCs transfected with the vector AAV2.7m8-ChR-tdT from an irradiance of 1015 photons.cm-2.s-1. Vector doses of 5.1010 and 5.1011 vg/eye transfect up to 7000 RGCs/mm2 in the perifovea, with no significant immune reaction. Furthermore, using a multielectrode array we recorded RGCs responses starting from 1ms stimulus duration. Using the recorded activity we were able to decode stimulus information and estimate a theoretical visual acuity of 20/249, above legal blindness. Altogether, our results pave the way for the ongoing clinical trial with the AAV2.7m8-ChrimsonR-tdT vector for vision restoration in patients affected by retinitis pigmentosa. One Sentence SummaryWe select here the vector and genetic construct best suited to provide vision restoration in patients suffering from retinopathies, we demonstrate temporal resolution compatible with high dynamic visual scenes and a visual acuity above legal blindness.

neuroscience↗

bioRxiv2020

Long term AAV2/9-mediated silencing of PMP22 prevents CMT1A disease in rats and validates skin biomarkers as treatment outcome measure

Charcot-Marie-Tooth disease 1A (CMT1A) results from a duplication of the PMP22 gene leading to an excess of PMP22, a deficit of myelination and an instability of the myelin sheath in peripheral nerves. Patients present with reduced nerve conduction velocity, muscle waste, hand and foot deformations and foot drop walking problems. As gene silencing therapy has been shown to be effective in other monogenic neurological disorders, we evaluated the safety and efficacy of recombinant adeno-associated viral vector serotype 9 (AAV2/9)-based gene therapy for CMT1A. AAV2/9-mediated delivery of eGFP and shRNAs targeting PMP22 mRNA in the sciatic nerve allowed widespread gene expression in myelinating Schwann cells in mouse, rat and nonhuman primate. The treatment restored wild-type PMP22 level, increased myelination and prevented motor and sensory impairment over 12 months in a rat model of CMT1A. Intra-nerve injection limited off-target transduction and immune response to barely detectable levels. A combination of previously characterized human skin biomarkers successfully discriminated treated animals from their untreated littermate controls indicating their potential use as part of outcome measures in future clinical trials. Our results support intra nerve injection of AAV2/9 as an effective strategy for the treatment of CMT1A as well as other demyelinating CMT diseases.

neuroscience↗

bioRxiv2019

Targeting MOG to skin macrophages prevents EAE in macaques through TGFβ-induced peripheral tolerance

To study the effect of vaccination on tolerization to the myelin antigen MOG we used a macaque model of experimental autoimmune encephalitis (EAE) in which immunization with recombinant human myelin oligodendrocyte glycoprotein (rhMOG) elicits brain inflammation and demyelination mediated by MOG-specific autoreactive CD4+ T lymphocytes and anti-MOG IgG. For antigen targeting to tolerizing antigen presenting cells, we used a recombinant antibody directed to the Dendritic Cells (DC)-Asialoglycoprotein receptor (DC-ASGPR). The intradermal administration of an anti-DC-ASGPR-MOG fusion protein, but not a control anti-DC-ASGPR-PSA (prostate specific antigen) protein, protected monkeys committed to develop EAE. Although effective treatment did not modify anti-MOG IgG production, it prevented the CD4+ T lymphocyte activation and pro-inflammatory cytokine production. Moreover, animals treated with anti-DC-ASGPR-MOG experienced a rise of MOG-specific CD4+CD25+FOXP3+CD39+ regulatory T cells as well as a TGF{beta}1, TGF{beta}2 and IL-8 upsurge after rhMOG re-immunization. Our results indicate that the pathogenicity of autoantibodies directed to MOG is mitigated in the presence of MOG-specific regulatory lymphocytes. This vaccination scheme appears suitable to treat relapsing autoimmune diseases with identified autoantigens such as that harboring anti-MOG or anti-AQP4 autoantibodies.

immunology↗