Biology subjects

Bimbi, G.

Publications and source records attributed to Bimbi, G..

3 recordsLinked to original sources

bioRxiv2026

A Single Lipid Nanoparticle Formulation Enables Delivery of Diverse RNA Therapeutics to Human Muscle Models of Duchenne Muscular Dystrophy

Duchenne muscular dystrophy is a lethal neuromuscular disorder caused by the absence of dystrophin, for which no curative treatment is available. RNA-based approaches have shown promising results; however, their evaluation is hindered by the lack of robust and rapid delivery methods for differentiated human muscle cells, which represent the most physiologically relevant in vitro models for assessing therapeutic strategies. Here, we establish a versatile lipid nanoparticle platform enabling efficient delivery of diverse RNA therapeutics across a range of human muscle models, including myotubes, induced pluripotent stem cell-derived myotubes, myoblasts, cardiomyocytes, and 3D engineered skeletal muscle tissues. Remarkably, a single commercially available lipid nanoparticle formulation supports delivery of cargos spanning more than 300-fold in size, from short antisense oligonucleotides ([~]20 nt) to complex CRISPR-based editors (up to [~]6.7 kb), including Cas9 nucleases, adenine base editors, and CRISPRa systems. This enables efficient gene correction and transcriptional modulation, resulting in dystrophin restoration or compensatory utrophin upregulation in relevant Duchenne muscular dystrophy models. Together, our results establish a single lipid nanoparticle formulation as a versatile platform for RNA delivery in human muscle systems and provide a practical framework for the rapid preclinical assessment of emerging therapies for Duchenne muscular dystrophy and other neuromuscular disorders. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=92 SRC="FIGDIR/small/741396v1_ufig1.gif" ALT="Figure 1"> View larger version (29K): org.highwire.dtl.DTLVardef@a18d71org.highwire.dtl.DTLVardef@4d0faforg.highwire.dtl.DTLVardef@140b078org.highwire.dtl.DTLVardef@1a235_HPS_FORMAT_FIGEXP M_FIG C_FIG Created in BioRender. Leclerc, D. (2026) https://BioRender.com/90h0fme

molecular biology↗

bioRxiv2023

Chemical-LTP induces confinment of BDNF mRNA under dendritic spines followed by BDNF protein accumulation inside the spines

The neurotrophin brain-derived neurotrophic factor (BDNF) plays a key role in neuronal development and synaptic plasticity. The discovery that BDNF mRNA can be transported in neuronal dendrites in an activity-dependent manner has suggested that its local translation may support synapse maturation and plasticity. However, a clear demonstration that BDNF mRNA is locally transported and translated at activated synapses in response to long-term potentiation (LTP) is still lacking. Here, we study the dynamics of BDNF mRNA dendritic trafficking following induction of chemical-LTP (cLTP). Dendritic transport of BDNF transcripts was analysed using the MS2 system for mRNA visualization, and chimeric BDNF-GFP constructs were used to monitor protein synthesis in living neurons. We found that within 15 following cLTP induction, most BDNF mRNA granules become stationary and transiently accumulate in the dendritic shaft at the basis of the spines similarly to the control CamkII mRNA which increased also inside the spines, at 60 post-cLTP. At 60 but not at 15 from cLTP induction, we observed an increase in BDNF protein levels within the spine. Taken together, these findings suggest that BDNF mRNA trafficking is arrested in the early phase of cLTP, providing a local source of mRNA for translation of BDNF at the basis of the spine followed in the late LTP phase, by translocation of the BDNF protein within the spine head. StatementBrain-derived neurotrophic factor (BDNF) plays a key role in neuronal development and synaptic plasticity. In this study, we investigate two unresolved questions in neuronal plasticity: a) whether the post-synaptically released BDNF can be locally synthesized in this compartment, and b) whether the local translation of BDNF occurs in dendrites, or within the spine. Using chimeric constructs ectopically expressed in living primary hippocampal neurons, we tracked BDNF mRNA trafficking within the dendrites and its local translation following induction of chemical-LTP (cLTP) by forskolin. We show that in the early phase of cLTP induction (15), BDNF mRNA becomes confined at the basis of the spines providing a local source for translation of the protein followed in the late LTP phase (60), by translocation of the BDNF protein within the spine head.

neuroscience↗

bioRxiv2021

MDGAs are fast-diffusing molecules that delay excitatory synapse development by altering neuroligin behavior

MDGAs are molecules that can bind neuroligins in cis and interfere with trans-synaptic neurexin-neuroligin interactions, thereby impairing synapse development. However, the sub-cellular localization and dynamics of MDGAs, as well as their specific mode of action in neurons are still unclear. Here, using both surface immunostaining of endogenous MDGAs and single molecule tracking of recombinant MDGAs in dissociated hippocampal neurons, we show that MDGA1 and MDGA2 molecules are homogeneously distributed and exhibit fast membrane diffusion, with a small reduction in mobility across neuronal maturation in culture Using shRNAs and CRISPR/Cas9 strategies to knock-down/out MDGA1 or MDGA2, we demonstrate an increase in the density of excitatory synapses accompanied by enhanced membrane immobilization and an increase in the phosphotyrosine level of neuroligins associated with excitatory post-synaptic differentiation. Finally, we show that decreasing MDGA expression level reduces the mobility of AMPA receptors and increases the frequency of AMPA receptor mediated mEPSCs. Overall, our results support a mechanism by which interactions between MDGAs and neuroligin-1 delays the assembly of functional excitatory synapses containing AMPA receptors.

neuroscience↗