Navegando por Autor "Dourlen, Pierre"
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Artigo Pyk2 overexpression in postsynaptic neurons blocks amyloid β1-42-induced synaptotoxicity in microfluidic co-cultures(Oxford University Press, 2020-08-28) Kilinc, Devrim; Vreulx, Anaїs-Camille; Mendes, Tiago; Flaig, Amandine; Coelho, Diego Marques; Verschoore, Maxime; Demiautte, Florie; Amouyel, Philippe; Eysert, Fanny; Dourlen, Pierre; Chapuis, Julien; Costa, Marcos Romualdo; Malmanche, Nicolas; Checler, Frédéric; Lambert, Jean-CharlesRecent meta-analyses of genome-wide association studies identified a number of genetic risk factors of Alzheimer’s disease; however, little is known about the mechanisms by which they contribute to the pathological process. As synapse loss is observed at the earliest stage of Alzheimer’s disease, deciphering the impact of Alzheimer’s risk genes on synapse formation and maintenance is of great interest. In this paper, we report a microfluidic co-culture device that physically isolates synapses from pre- and postsynaptic neurons and chronically exposes them to toxic amyloid β peptides secreted by model cell lines overexpressing wild-type or mutated (V717I) amyloid precursor protein. Co-culture with cells overexpressing mutated amyloid precursor protein exposed the synapses of primary hippocampal neurons to amyloid β1-42 molecules at nanomolar concentrations and induced a significant decrease in synaptic connectivity, as evidenced by distance-based assignment of postsynaptic puncta to presynaptic puncta. Treating the cells with antibodies that target different forms of amyloid β suggested that low molecular weight oligomers are the likely culprit. As proof of concept, we demonstrate that overexpression of protein tyrosine kinase 2 beta (Pyk2) –an Alzheimer’s disease genetic risk factor involved in synaptic plasticity and shown to decrease in Alzheimer’s disease brains at gene expression and protein levels– selectively in postsynaptic neurons is protective against amyloid β1-42-induced synaptotoxicity. In summary, our lab-on-a-chip device provides a physiologically-relevant model of Alzheimer’s disease-related synaptotoxicity, optimal for assessing the impact of risk genes in pre- and postsynaptic compartmentsArtigo The Alzheimer susceptibility gene BIN1 induces isoform-dependent neurotoxicity through early endosome defects(2022-01-08) Lambert, Erwan; Saha, Orthis; Landeira, Bruna Soares; Farias, Ana Raquel Melo de; Hermant, Xavier; Carrier, Arnaud; Pelletier, Alexandre; Gadaut, Johanna; Davoine, Lindsay; Dupont, Cloé; Amouyel, Philippe; Bonnefond, Amélie; Lafont, Frank; Abdelfettah, Farida; Verstreken, Patrik; Chapuis, Julien; Barois, Nicolas; Delahaye, Fabien; Dermaut, Bart; Lambert, Jean‑Charles; Costa, Marcos Romualdo; Dourlen, PierreThe Bridging Integrator 1 (BIN1) gene is a major susceptibility gene for Alzheimer’s disease (AD). Deciphering its pathophysiological role is challenging due to its numerous isoforms. Here we observed in Drosophila that human BIN1 isoform1 (BIN1iso1) overexpression, contrary to human BIN1 isoform8 (BIN1iso8) and human BIN1 isoform9 (BIN1iso9), induced an accumulation of endosomal vesicles and neurodegeneration. Systematic search for endosome regulators able to prevent BIN1iso1-induced neurodegeneration indicated that a defect at the early endosome level is responsible for the neurodegeneration. In human induced neurons (hiNs) and cerebral organoids, BIN1 knock-out resulted in the narrowing of early endosomes. This phenotype was rescued by BIN1iso1 but not BIN1iso9 expression. Finally, BIN1iso1 overexpression also led to an increase in the size of early endosomes and neurodegeneration in hiNs. Altogether, our data demonstrate that the AD susceptibility gene BIN1, and especially BIN1iso1, contributes to earlyendosome size deregulation, which is an early pathophysiological hallmark of AD pathology