Neuronal and astrocytic contributions to Huntington’s disease dissected with zinc finger protein transcriptional repressors

Abstract

Huntington's disease (HD) is caused by expanded CAG repeats in the huntingtin gene (HTT) resulting in expression of mutant HTT proteins (mHTT) with extended polyglutamine tracts, including in striatal neurons and astrocytes. It is unknown whether pathophysiology invivo can be attenuated by lowering mHTT in either cell type throughout the brain, and the relative contributions of neurons and astrocytes to HD remain undefined. We use zinc finger protein (ZFP) transcriptional repressors to cell-selectively lower mHTT invivo. Astrocytes display loss of essential functions such as cholesterol metabolism that are partly driven by greater neuronal dysfunctions, which encompass neuromodulation, synaptic, and intracellular signaling pathways. Using transcriptomics, proteomics, electrophysiology, and behavior, we dissect neuronal and astrocytic contributions to HD pathophysiology. Remarkably, brain-wide delivery of neuronal ZFPs results in strong mHTT lowering, rescue of HD-associated behavioral and molecular phenotypes, and significant extension of lifespan, findings that support translational development.