Striatal Projection Neurons Require Huntingtin for Synaptic Connectivity and Survival

Abstract

Summary: Huntington’s disease (HD) is caused by an autosomal dominant polyglutamine expansion mutation of Huntingtin (HTT). HD patients suffer from progressive motor, cognitive, and psychiatric impairments, along with significant degeneration of the striatal projection neurons (SPNs) of the striatum. HD is widely accepted to be caused by a toxic gain-of-function of mutant HTT. However, whether loss of HTT function, because of dominant-negative effects of the mutant protein, plays a role in HD and whether HTT is required for SPN health and function are not known. Here, we delete Htt from specific subpopulations of SPNs using the Cre-Lox system and find that SPNs require HTT for motor regulation, synaptic development, cell health, and survival during aging. Our results suggest that loss of HTT function in SPNs could play a critical role in HD pathogenesis. : Burrus et al. show that striatal projection neurons require Huntingtin, the gene mutated in Huntington’s disease, for normal synaptic connectivity, regulated gene expression, and neuronal survival with aging. Loss of Huntingtin from striatal neurons recapitulates several features of Huntington’s disease pathology, an important consideration for therapies non-specifically targeting Huntingtin expression. Keywords: Huntington's Disease, basal ganglia, striatum, synaptic connectivity, neuronal survival