Deciphering molecular mechanisms of late-LTP with the Timelapse-Patch-Seq (TiPS) technique – TiPS

Long-Term Potentiation(LTP) mechanism is a widely accepted model of cellular processes that could underlie learning and memory. While much is known about early phase of LTP, many questions remain regarding the long-term maintenance of LTP. To address this important point, we developed a highly innovative methodology: Timelapse-Patch-Seq(TiPS). This approach is based on the repetitive whole-cell patch-clamp recordings of unitary synaptic connections between two neurons in a preserved neuronal network(e.g. hippocampal organotypic slices) and combined each time with RNA-seq and 3D live-imaging. This multimodal and longitudinal approach allows: (1) to genetically manipulate, stimulate and visualize pre and postsynaptic elements together at individual synaptic sites, (2) to monitor each of these elements at the structural and physiological levels at multiple time points over long periods of time (up to several weeks) and (3) to correlate synaptic changes with transcriptomic regulation through RNA-seq and bioinformatic analysis. This approach offers a unique opportunity to link the functional, transcriptomic and morphologic states of connected neurons before and after eliciting synaptic plasticity. Since LTP involves modifications in the nanoarchitecture of synapses such as the organization of synaptic proteins in nanodomains, TiPS will be combined with expansion microscopy to provide a comprehensive picture of the cellular and molecular events supporting late-LTP. This interdisciplinary project will identify new molecular mechanisms of late-LTP and should highlight the relative importance of the pre- and post-synaptic compartments. Identifying the molecular mechanisms of late-LTP will be a milestone in the understanding of learning and memory. In addition, neurodegenerative diseases such as Alzheimer’s disease could be investigated with the same approach in a follow-up project to open new therapeutic avenues.