title: AAV-mediated delivery of the transcription factor XBP1s into the striatum reduces mutant Huntingtin aggregation in a mouse model of Huntington's disease.
abstract: Huntington's disease (HD) is caused by mutations that expand a polyglutamine region in the amino-terminal domain of Huntingtin (Htt), leading to the accumulation of intracellular inclusions and progressive neurodegeneration. Recent reports indicate the engagement of endoplasmic reticulum (ER) stress responses in human HD post mortem samples and animal models of the disease. Adaptation to ER stress is mediated by the activation of the unfolded protein response (UPR), an integrated signal transduction pathway that attenuates protein folding stress by controlling the expression of distinct transcription factors including X-Box binding protein 1 (XBP1). Here we targeted the expression of XBP1 on a novel viral-based model of HD. We delivered an active form of XBP1 locally into the striatum of adult mice using adeno-associated vectors (AAVs) and co-expressed this factor with a large fragment of mutant Htt as a fusion protein with RFP (Htt588(Q95)-mRFP) to directly visualize the accumulation of Htt inclusions in the brain. Using this approach, we observed a significant reduction in the accumulation of Htt588(Q95)-mRFP intracellular inclusion when XBP1 was co-expressed in the striatum. These results contrast with recent findings indicating a protective effect of XBP1 deficiency in neurodegeneration using knockout mice, and suggest a potential use of gene therapy strategies to manipulate the UPR in the context of HD.
authors.affiliation: Biomedical Neuroscience Institute, Faculty of Medicine, University of Chile, Santiago, Chile.
authors.forename: Amparo
authors.initials: A
authors.lastname: Zuleta
authors.forename: Rene L
authors.initials: RL
authors.lastname: Vidal
authors.forename: Donna
authors.initials: D
authors.lastname: Armentano
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Parsons
authors.forename: Claudio
authors.initials: C
authors.lastname: Hetz
mesh_terms: D000818:Animals; D003342:Corpus Striatum / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism*; D000229:Dependovirus; D004195:Disease Models, Animal; D059865:Endoplasmic Reticulum Stress / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods; D005822:Genetic Vectors; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000235:genetics / Q000378:metabolism* / Q000628:therapy; D008297:Male; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors / Q000235:genetics* / Q000378:metabolism*; D014161:Transduction, Genetic; D056811:Unfolded Protein Response / Q000235:genetics*; D000071717:X-Box Binding Protein 1
chemical_list: D004268:DNA-Binding Proteins; C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D000071701:Regulatory Factor X Transcription Factors; D014157:Transcription Factors; D000071717:X-Box Binding Protein 1; C000605543:XBP1 protein, human; C000605544:Xbp1 protein, mouse