Biology subjects

Le Meur, G.

Publications and source records attributed to Le Meur, G..

3 recordsLinked to original sources

bioRxiv2026

Intracellular accumulation of AAV6 genomes governs microglia reactivity and the inflammatory response in retinal gene therapy

Adeno-associated viral (AAV) vectors possess immense potential for gene therapy applications. However, microglia can mount an immune response against AAV vectors. Yet, microglia are therapeutic targets since they play a driving role in the progression of neurodegenerative diseases. Thus, it is critical to understand the cellular processes driving the microglia-mediated immune response against AAV vectors. To this end, we modelled AAV6 induced inflammation upon retinal gene therapy in minipigs. Upon AAV6 administration, the IBA1+ cells demonstrated a morphological transition to the amoeboid form, indicating microglial reactivity. We also observed the invasion of peripheral immune cells in the retina. To elucidate the underlying molecular mechanisms, we transduced human iPSC derived microglia-like cells (iMGLs) in vitro with AAV6 and AAV8 respectively. Only AAV6 transduced iMGLs exhibited morphological features and a transcriptomic signature of microglial reactivity. The magnitude of intracellular AAV6 viral genomes was significantly higher as compared to the AAV8 condition. The elevated levels of intracellular AAV6 genomes induced a DNA damage response in AAV6-transduced iMGLs, which is a key feature of neuroinflammation-linked microglial reactivity. Thus, our work highlights the impact of intracellular viral genome accumulation on microglial reactivity and its implications for retinal gene therapy associated inflammation.

neuroscience↗

bioRxiv2023

Nucleotide sharing through gap junctions buffers replication stress

Cell proliferation underlying tissue growth and homeostasis, requires high levels of metabolites such as deoxynucleotides (dNTPs). The dNTP pool is known to be tightly cell-autonomously regulated via de novo synthesis and salvage pathways. Here, we reveal that nucleotides can also be provided to cells non-autonomously by surrounding cells within a tissue. Using Drosophila epithelial tissues as models, we find that adult intestinal stem cells are highly sensitive to nucleotide depletion whereas wing progenitor cells are not. Wing progenitor cells share nucleotides through gap junction connections, allowing buffering of replication stress induced by nucleotide pool depletion. Adult intestinal stem cells, however, lack gap junctions and cannot receive dNTPs from neighbors. Collectively, our data suggest that gap junction-dependent sharing between cells can contribute to dNTP pool homeostasis in vivo. We propose that inherent differences in cellular gap junction permeability can influence sensitivity to fluctuations of intracellular dNTP levels. One-Sentence SummaryThe nucleotide pool can be shared between adjacent cells through gap junctions allowing tissue-level buffering of replication stress.

developmental biology↗

bioRxiv2022

Mannose-coupled AAV2: a second generation AAV vector for increased retinal gene therapy efficiency

Inherited retinal diseases are a leading and untreatable cause of blindness and are therefore candidate diseases for gene therapy. Recombinant vectors derived from adeno-associated virus (rAAV) are currently the most promising vehicles for in vivo therapeutic gene delivery to the retina. However, there is a need for novel AAV-based vectors with greater efficacy for ophthalmic applications, as underscored by recent reports of dose-related inflammatory responses in clinical trials of rAAV-based ocular gene therapies. Improved therapeutic efficacy of vectors would allow for decreases in the dose delivered, with consequent reductions in immune reactions. Here, we describe the development of new rAAV vectors using bioconjugation chemistry to modify the rAAV capsid, thereby improving the therapeutic index. Covalent coupling of a mannose ligand, via the formation of a thiourea bond, to the amino groups of the rAAV capsid significantly increases vector transduction efficiency of both rat and nonhuman primate retinas. These optimized rAAV vectors have important implications for the treatment of a wide range of retinal diseases.

bioengineering↗