RNA biology and neuroglial function: resolving the cellular and subcellular transcriptome in myotonic dystrophy brains, towards new brain gene therapy

ongoing

RNA biology is critical for the molecular orchestration of the interplay between specialized brain cell types, and disrupted RNA processing, can cause human disease. A prime example is Myotonic Dystrophy type 1(DM1), a multisystemic disorder caused by the expansion of a non-coding trinucleotide DNA repeat and that involves cognitive impairment and behavioral changes. Molecular pathogenesis is driven by the nuclear accumulation of RNA foci, which sequester RNA-binding proteins that regulate splicing, polyadenylation and subcellular localization of downstream transcripts. However, we do not know the cell populations, molecular pathways and cell-cell interactions primarily affected in the brain. A critical question to develop effective molecular therapies. My host laboratory developed a unique mouse model of DM1 that mirrors the spatiotemporal expression of toxic RNA and relevant brain phenotypes. Using these mice, I will fill three knowledge gaps:(1) I will employ advanced spatial transcriptomics to unravel the vulnerability of diverse cell types throughout brain development and aging;(2) I will use the TRAP technology to uncover subcellular transcriptomic abnormalities in specialized neuron-astrocyte contacts and identify pivotal disease intermediates of neuroglial miscommunication;(3) I will use my expertise in AAV-mediated brain gene delivery to test the capacity of engineered protein decoys, developed in my host laboratory, to release the RNA-binding proteins sequestered in brain cells and correct the behavioral, molecular neurobiological deficit in DM1 mice. Through the integration of cutting-edge transcriptomics with a new focus on synaptic neuroglial communication, I will elucidate DM1 brain pathogenesis with unprecedented spatiotemporal resolution, and offer a framework to understand other conditions mediated by toxic RNA repeats, for which DM1 serves as a paradigm. Simultaneously, my project will enhance our understanding of RNA biology in the brain.