Biology subjects

Barthelemy, F.

Publications and source records attributed to Barthelemy, F..

3 recordsLinked to original sources

bioRxiv2026

Structural engineering of dual-targeting antisense oligonucleotides enhances exon 44 skipping for treating Duchenne muscular dystrophy

Antisense oligonucleotides (ASOs) inducing exon-skipping during pre-mRNA splicing offer promising treatment for diseases such as Duchenne muscular dystrophy. Recently, dual-targeting ASOs that simultaneously bind two splicing regulatory sequences have been shown to improve exon-skipping efficiency. Current ASOs are designed to interact with target RNAs solely based on Watson-Crick base pairing. Here we report the development of dual-targeting three-dimensional bridge (3D-bridge) ASOs in which tertiary interactions are engineered to increase target-binding affinity and the number of target residues occupied. We designed a 3D-bridge ASO for skipping exon 44 of dystrophin mRNA and biochemically validated its enhanced binding affinity for the target RNA over a similar ASO with the tertiary interactions disrupted. We subsequently optimized the 3D-bridge ASO by varying its ends and ribose chemical modifications using patient-derived induced directly reprogrammed myotubes and identified an LNA/DNA mixmer as the most potent. We further demonstrate enhanced exon-skipping efficacy and potency of the 3D-bridge ASO compared to previously reported ASOs in myotubes differentiated from patient-derived primary myoblasts and MyoD-reprogrammed fibroblasts harboring mutations amenable to reframing through exon 44 skipping. In conclusion, the 3D-bridge ASO technology improves the current dual-targeting design, demonstrating the utility and power of structure-based ASO design methods.

pharmacology and toxicology↗

bioRxiv2026

Reciprocal Fronto-Parietal Interactions Support Motor Anticipation during Sequential Reaching

Motor planning is a highly flexible process that adapts to changing behavioral demands. Frontal and parietal circuits are considered as critical nodes that support planning processes. However, it remains unclear whether the coordination of motor and parietal areas is preserved or adjusted in response to varying behavioral contexts. To address this open question, we trained two rhesus macaques to perform a visually-guided sequential reaching task, in which they could adapt their behavior to varying degrees of target predictability within the sequence. Analysis of eye and hand movements revealed distinct visuomotor strategies that were reflected in corresponding neural activity patterns. During motor anticipation, the direction of the upcoming reach toward predictable targets could be decoded from preparatory neural activity prior to target onset both in motor regions (PMd/M1) and parietal area 7A, whereas during reactive movements directional information emerged only after target onset. Using feature-specific information transfer analysis, we found that information about the upcoming movement direction was transmitted between 7A and PMd/M1 through bidirectional interactions. This pattern of interactions was preserved during motor anticipation and shifted earlier in time with respect to target onset. Our findings thus support a reciprocal fronto-parietal network that flexibly adjusts the timing of preparatory activity as different strategies are employed under varying behavioral constraints. Contrary to classical hierarchical models predicting serial activation across parietal and motor areas, parietal-to-motor interactions did not precede motor-to-parietal interactions, consistent with a heterarchical organization of cortical processing during flexible motor planning.

neuroscience↗

bioRxiv2022

Single nuclei transcriptomics of muscle reveals intra-muscular cell dynamics linked to dystrophin loss and rescue

In Duchenne muscular dystrophy, dystrophin loss leads to chronic muscle damage, dysregulation of repair, fibro-fatty replacement, and weakness. We develop methodology to efficiently isolate individual nuclei from frozen skeletal muscle, allowing single nuclei sequencing of irreplaceable archival samples from small samples. We apply this method to identify cell and gene expression dynamics within human DMD and mdx mouse muscle, characterizing treatment effects of dystrophin rescue by exon skipping therapy at single nuclei resolution. DMD exon 23 skipping events are directly observed and increased in myonuclei from treated mice. We describe partial rescue of type IIa and IIx myofibers, expansion of a novel MDSC-like myeloid population, recovery of repair/remodeling M2-macrophage, and repression of inflammatory POSTN1+ fibroblasts in response to exon skipping and partial dystrophin restoration. Use of this method enables exploration of cellular and transcriptomic mechanisms of dystrophin loss and repair.

genetics↗