publication detail
A multimodal nanopipette-based imaging platform for exploring brain communication
AUTHORS
Document type
Poster communications
Résumé
N-methyl-D-aspartate receptors (NMDARs) are ionotropic glutamate receptors that are critical for multiple aspects of brain physiology and pathology. They are essential for neural coding and transducing specific patterns of synaptic activity into long-term structural and functional changes of synapses and, therefore, vital to cognitive processes. Conversely, malfunction of these receptors is linked to the etiology of brain disorders such as Alzheimer disease and schizophrenia, for which there is no treatment. Therefore, interpreting mechanisms associated in their regulation is very important, however some of the molecular mechanisms governing the functioning of NMDARs are still unknown due to the lack of suitable techniques [1-2]. We are in particular interested in measuring the concentrations of NMDARs' coagonists, glycine and D-Serine, with high spatial resolution in order to understand their function in physiological and possible pathological conditions [3-4]. We propose the development of a multimodal tool based on the scanning ion conductance microscopy (SICM), a well established scanning probe microscopy technique that provides topographic information of biological samples and living tissues with high resolution [5]. Excitingly, in our imaging platform, the scanning probe will also be capable of measuring D-serine and glycine concentrations at synaptic and extra-synaptic nanodomains with a nanometer scale resolution, by means of an electrochemical enzymatic biosensors embedded in the tip of probe itself. The first step towards the employment of the platform for our purpose consisted of several tests to adapt the functioning of the setup for imaging two different cell types: neuron-like PC12 cells and MDCK cells. In parallel, first stages of the nano-pipette probes functionalization have been investigated to make it suitable for future inclusion of the enzymatic biosensor. Merging the imaging capabilities of the methodology and the advancements in tip engineering will allow to measure, in a network of mature neurons, the concentrations of the two co-agonists of NMDARs, while providing the topography of the synapses where these molecules are active. Bibliography 1. Traynelis, S. F. et al. Glutamate Receptor Ion Channels: Structure, Regulation, and Function. Pharmacological Reviews 62, 405{496 (2010) 2. Paoletti, P., Bellone, C. Zhou, Q. NMDA receptor subunit diversity: impact on receptor properties, synaptic plasticity and disease.Nature Reviews Neuroscience 14, 383-400 (2013) 3. Mothet, J.-P., le Bail, M. Billard, J.-M. Time and space profiling of NMDA receptor co-agonist functions. Journal of Neurochemistry 135,210-225 (2015). 4. Mothet, J.-P. et al. D-Serine is an endogenous ligand for the glycine site of the N-methyl-D-aspartate. receptor. Proceedings of the National Academy of Sciences 97, 4926-4931 (2000). 5. Zhu, C., Huang, K., Siepser, N. P., Baker, Scanning Ion Conductance Microscopy, Chemical Reviews 121, 11726-11768 (2021).