Human single-chain Fv intrabodies counteract in situ huntingtin aggregation in cellular models of Huntington's disease.
This investigation was pursued to test the use of intracellular antibodies (intrabodies) as a means of blocking the pathogenesis of Huntington's disease (HD). HD is characterized by abnormally elongated polyglutamine near the N terminus of the huntingtin protein, which induces pathological protein-protein interactions and aggregate formation by huntingtin or its exon 1-containing fragments. Selection from a large human phage display library yielded a single-chain Fv (sFv) antibody specific for the 17 N-terminal residues of huntingtin, adjacent to the polyglutamine in HD exon 1. This anti-huntingtin sFv intrabody was tested in a cellular model of the disease in which huntingtin exon 1 had been fused to green fluorescent protein (GFP). Expression of expanded repeat HD-polyQ-GFP in transfected cells shows perinuclear aggregation similar to human HD pathology, which worsens with increasing polyglutamine length; the number of aggregates in these transfected cells provided a quantifiable model of HD for this study. Coexpression of anti-huntingtin sFv intrabodies with the abnormal huntingtin-GFP fusion protein dramatically reduced the number of aggregates, compared with controls lacking the intrabody. Anti-huntingtin sFv fused with a nuclear localization signal retargeted huntingtin analogues to cell nuclei, providing further evidence of the anti-huntingtin sFv specificity and of its capacity to redirect the subcellular localization of exon 1. This study suggests that intrabody-mediated modulation of abnormal neuronal proteins may contribute to the treatment of neurodegenerative diseases such as HD, Alzheimer's, Parkinson's, prion disease, and the spinocerebellar ataxias.
Lecerf
J M
JM
IntraImmune Therapies, Inc., Lexington, MA 02215, USA.
Shirley
T L
TL
Zhu
Q
Q
Kazantsev
A
A
Amersdorfer
P
P
Housman
D E
DE
Messer
A
A
Huston
J S
JS
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D049452:Green Fluorescent Proteins; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000473:pathology*; D007135:Immunoglobulin Variable Region / Q000276:immunology*; D008164:Luminescent Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000276:immunology / Q000378:metabolism*; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism*; D011485:Protein Binding
C086055:HTT protein, human; D000071058:Huntingtin Protein; D007135:Immunoglobulin Variable Region; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D049452:Green Fluorescent Proteins