Our research activities encompass the development and optimization of nucleic acids therapeutic. We are working on their formulations, delivery, targeting according to routes of administration. This is a multidisciplinary research field requiring different disciplines as chemistry, physico-chemistry, molecular and cell biology.

Regarding gene transfer, we have now identified several devices for designing a DNA Integrative Artificial virus that could be an alternative of recombinant virus. This is tackled by optimization of each known devices, their packaging. For this, bioengineering of plasmid DNA is developed by coupling specific intracellular signals as peptide mediated cytosolic transport and DNA sequence for nuclear import. We also explore the co-delivery approach of siRNAs, anti-miRNAs and/or DNA decoys against oncogenic genes. DNA decoys are based on bioengineered small nucleic acids for cell and intracellular targeting.

Our long-lasting expertise in plasmid DNA transfer by synthetic vectors is exploited back to optimize the delivery of other types of nucleic acids including oligonucleotides, DNA decoy, siRNA, microRNA and mRNA. Our main original formulation called Lipopolyplexes is an advanced hybrid lipid polymer shell mRNA nanoparticle (LPR) endowed with a ligand as trimannose sugar tree for dendritic cells targeting. LPR comprising mRNA coding for tumor antigens have been found to be highly efficient as vaccines against cancer. We wish to strengthen this axis by improving in vivo delivery for pre-clinical trials and hopefully clinical trials.

Messenger RNA vaccines and therapeutics

These recent years, messenger RNA have been emerged as new biopharmaceuticals. Today, mRNA are produced by in vitro translation. Despite the optimization of mRNA production, it is still costly since it requires many reagents and steps. The safety of the process avoiding the cell use is one of the main claim of this synthetic technology. However, searching for another option that allows a large batch production could be advantageous for clinical development. This is the challenge we took by designing a cell factory based on yeast for mRNA production. This unicellular eukaryote, regarded as safe for bioproduction, is extremely useful in RNA field because it possesses an RNA metabolism transposable to higher eukaryotes. A vast array of genetic tools, molecular and biochemical methods are available for yeast studies. We genetically engineered yeast cells to produce on demand mRNA of interest and to target them in a specific compartment that is easy to purify. We succeeded to generate transcriptional yeast mutants that express mature and intact heterologous mRNA targeted and confined inside retrosomes. Once extracted, the bio produced mRNA was efficiently expressed in cellulo and in vivo. To our knowledge, this study is the first proof of concept study indicating the feasibility of mRNA bioproduction. (Pigeon et al., PCT/EP 2018/025066)

The team is also working on sonoporation based on ultrasound (US) and microbubbles (MB)  to deliver nucleic acids and drugs in vitro and in vivo. We made a pioneer study revealing the intracellular translation of microbubbles during efficient drug delivery by sonoporation, well acknowledged in the field. Current developments of original cationic MB with smaller size and high capacity of encapsulation. The main application is the delivery of plasmid DNA/mRNA to restore the expression of mutated genes for genetic disease and glioblastoma. C’Valo, a Région Centre Val de Loire instrument that accelerates the academic research into innovation, supports this project.