title: Suppression of polyglutamine-induced toxicity in cell and animal models of Huntington's disease by ubiquilin.
abstract: Expanded polyglutamine (polyQ) tracts are associated with the induction of protein aggregation and cause cytotoxicity in nine different neurodegenerative disorders. Here, we report that ubiquilin suppresses polyQ-induced protein aggregation and toxicity in cells and in an animal model of Huntington's disease. Overexpression of ubiquilin in HeLa cells and primary neurons reduced aggregation of polyQ-containing proteins and cell death induced by overexpression of a green fluorescent protein (GFP)-huntingtin fusion protein containing 74 polyQ repeats [GFP-Htt(Q74)], in a dose-dependent manner. Moreover, overexpression of ubiquilin suppressed oxidative stress-induced cell death in HeLa cell lines stably expressing GFP-Htt(Q74). In contrast, knockdown of ubiquilin expression in these cell lines was associated with increases in DNA fragmentation, caspase activation, GFP-fusion protein aggregation, and cell death. Caenorhabditis elegans lines expressing GFP-Htt fusion proteins in body wall muscle displayed a polyQ repeat length-dependent decrease in body movement compared with wild-type animals. RNA interference of the C. elegans ubiquilin gene exacerbated the motility defect, whereas overexpression of ubiquilin prevented, and could rescue, loss of worm movement induced by overexpression of GFP-Htt(Q55). These results suggest that ubiquilin might be a novel therapeutic target for treating polyQ diseases.
authors.affiliation: Medical Biotechnology Center, Institute for Neurodegenerative Diseases, University of Maryland Biotechnology Institute, 725 West Lombard Street, Baltimore, MD 21201, USA.
authors.forename: Hongmin
authors.initials: H
authors.lastname: Wang
authors.forename: Precious J
authors.initials: PJ
authors.lastname: Lim
authors.forename: Chaobo
authors.initials: C
authors.lastname: Yin
authors.forename: Matthias
authors.initials: M
authors.lastname: Rieckher
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Vogel
authors.forename: Mervyn J
authors.initials: MJ
authors.lastname: Monteiro
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D030801:Animals, Genetically Modified; D000071183:Autophagy-Related Proteins; D001522:Behavior, Animal / Q000502:physiology; D017173:Caenorhabditis elegans / Q000235:genetics / Q000378:metabolism; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D002460:Cell Line; D002478:Cells, Cultured; D004195:Disease Models, Animal; D006367:HeLa Cells; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D009474:Neurons / Q000378:metabolism*; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics; D010455:Peptides / Q000037:antagonists & inhibitors* / Q000633:toxicity*; D034622:RNA Interference; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000071183:Autophagy-Related Proteins; D002352:Carrier Proteins; D018797:Cell Cycle Proteins; C086055:HTT protein, human; D000071058:Huntingtin Protein; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; C107792:UBQLN1 protein, human; C097188:polyglutamine