A human single-chain Fv intrabody preferentially targets amino-terminal Huntingtin's fragments in striatal models of Huntington's disease.
Amino-terminal fragments of huntingtin (htt) appear to result from proteolytic processing of the full-length protein in Huntington's disease (HD), and fragments containing pathological expansions of polyglutamine elicit toxicity in model systems. Such fragments are sequestered into insoluble aggregates, which may initially serve a cellular protective mechanism, while soluble fragments and/or oligomers may be a more acute toxic species. Agents which enhance mutant htt clearance have shown therapeutic potential in animal models of HD. Here, we present the first evidence of an htt-specific single-chain Fv intrabody (C4) that selectively targets the soluble fraction of amino-terminal htt fragments. Our findings suggest that the C4 intrabody binds weakly, but does not alter the levels of endogenous, full-length htt. C4 appears to decrease the steady-state levels of amino-terminal htt fragments by binding to non-aggregated, but not aggregated, htt species. Intrabodies may be used as potential curative agents, and as drug discovery tools, for HD and other misfolded protein disorders.
Miller
Todd W
TW
Division of Genetic Disorders Wadsworth Center, New York State Department of Health, and Department of Biomedical Sciences, University at Albany, NY 12208, USA.
Zhou
Chun
C
Gines
Silvia
S
MacDonald
Marcy E
ME
Mazarakis
Nicholas D
ND
Bates
Gillian P
GP
Huston
James S
JS
Messer
Anne
A
D000818:Animals; D001666:Binding Sites, Antibody; D002460:Cell Line; D003342:Corpus Striatum / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D018390:Gene Targeting / Q000379:methods*; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*; D007128:Immunoglobulin Fragments / Q000494:pharmacology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*
C086055:HTT protein, human; C506812:Htt protein, mouse; D000071058:Huntingtin Protein; D007128:Immunoglobulin Fragments; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C055966:immunoglobulin Fv