Short G-rich oligonucleotides as a potential therapeutic for Huntington's Disease.
BACKGROUND
Huntington's Disease (HD) is an inherited autosomal dominant genetic disorder in which neuronal tissue degenerates. The pathogenesis of the disease appears to center on the development of protein aggregates that arise initially from the misfolding of the mutant HD protein. Mutant huntingtin (Htt) is produced by HD genes that contain an increased number of glutamine codons within the first exon and this expansion leads to the production of a protein that misfolds. Recent studies suggest that mutant Htt can nucleate protein aggregation and interfere with a multitude of normal cellular functions.


RESULTS
As such, efforts to find a therapy for HD have focused on agents that disrupt or block the mutant Htt aggregation pathway. Here, we report that short guanosine monotonic oligonucleotides capable of adopting a G-quartet structure, are effective inhibitors of aggregation. By utilizing a biochemical/immunoblotting assay as an initial screen, we identified a 20-mer, all G-oligonucleotide (HDG) as an active molecule. Subsequent testing in a cell-based assay revealed that HDG was an effective inhibitor of aggregation of a fusion protein, comprised of a mutant Htt fragment and green fluorescent protein (eGFP). Taken together, our results suggest that a monotonic G-oligonucleotide, capable of adopting a G-quartet conformation is an effective inhibitor of aggregation. This oligonucleotide can also enable cell survival in PC12 cells overexpressing a mutant Htt fragment fusion gene.


CONCLUSIONS
Single-stranded DNA oligonucleotides capable of forming stable G-quartets can inhibit aggregation of the mutant Htt fragment protein. This activity maybe an important part of the pathogenecity of Huntington's Disease. Our results reveal a new class of agents that could be developed as a therapeutic approach for Huntington's Disease.
Skogen
Michael
M
Department of Biological Sciences, University of Delaware, Delaware Biotechnology Institute, 15 Innovation Way, Newark, DE 19711, USA. skogenm@udel.edu
Roth
Jennifer
J
Yerkes
Sarah
S
Parekh-Olmedo
Hetal
H
Kmiec
Eric
E
D000704:Analysis of Variance; D000818:Animals; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D042622:DNA Repeat Expansion; D005434:Flow Cytometry / Q000379:methods; D049452:Green Fluorescent Proteins / Q000378:metabolism; D006151:Guanosine / Q000737:chemistry*; D006801:Humans; D000071058:Huntingtin Protein; D006816:Huntington Disease / Q000188:drug therapy* / Q000378:metabolism; D002479:Inclusion Bodies / Q000187:drug effects*; D016296:Mutagenesis / Q000502:physiology; D050505:Mutant Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D009841:Oligonucleotides / Q000737:chemistry / Q000627:therapeutic use*; D051381:Rats; D013057:Spectrum Analysis / Q000379:methods; D014162:Transfection / Q000379:methods
C086055:HTT protein, human; D000071058:Huntingtin Protein; D050505:Mutant Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D009841:Oligonucleotides; D006151:Guanosine; D049452:Green Fluorescent Proteins