Downregulation of glial genes involved in synaptic function mitigates Huntington's disease pathogenesis
Tarik Seref Onur, Andrew Laitman, Zhao He, Ryan Keyho, Hye Min Kim, Jennifer Wang, Megan Mair, Huilan Wang, Lifang Li, Alma Perez, María de Haro, Ying‐Wooi Wan, Genevera I. Allen, Boxun Lu, Ismael Al‐Ramahi, Zhandong Liu, Juan Botas
Abstract
Most research on neurodegenerative diseases has focused on neurons, yet glia help form and maintain the synapses whose loss is so prominent in these conditions. To investigate the contributions of glia to Huntington's disease (HD), we profiled the gene expression alterations of Drosophila expressing human mutant Huntingtin (m HTT ) in either glia or neurons and compared these changes to what is observed in HD human and HD mice striata. A large portion of conserved genes are concordantly dysregulated across the three species; we tested these genes in a high-throughput behavioral assay and found that downregulation of genes involved in synapse assembly mitigated pathogenesis and behavioral deficits. To our surprise, reducing d NRXN3 function in glia was sufficient to improve the phenotype of flies expressing m HTT in neurons, suggesting that mHTT's toxic effects in glia ramify throughout the brain. This supports a model in which dampening synaptic function is protective because it attenuates the excitotoxicity that characterizes HD.