Identical oligomeric and fibrillar structures captured from the brains of R6/2 and knock-in mouse models of Huntington's disease.
Huntington's disease (HD) is a late-onset neurodegenerative disorder that is characterized neuropathologically by the presence of neuropil aggregates and nuclear inclusions. However, the profile of aggregate structures that are present in the brains of HD patients or of HD mouse models and the relative contribution of specific aggregate structures to disease pathogenesis is unknown. We have used the Seprion ligand to develop a highly sensitive enzyme-linked immunosorbent assay (ELISA)-based method for quantifying aggregated polyglutamine in tissues from HD mouse models. We used a combination of electron microscopy, atomic force microscopy (AFM) and sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) to investigate the aggregate structures isolated by the ligand. We found that the oligomeric, proto-fibrillar and fibrillar aggregates extracted from the brains of R6/2 and HdhQ150 knock-in mice were remarkably similar. Using AFM, we determined that the nanometre globular oligomers isolated from the brains of both mouse models have dimensions identical to those generated from recombinant huntingtin exon 1 proteins. Finally, antibodies that detect exon 1 Htt epitopes differentially recognize the ligand-captured material on SDS-PAGE gels. The Seprion-ligand ELISA provides an assay with good statistical power for use in preclinical pharmacodynamic therapeutic trials or to assess the effects of the genetic manipulation of potential therapeutic targets on aggregate load. This, together with the ability to identify a spectrum of aggregate species in HD mouse tissues, will contribute to our understanding of how these structures relate to the pathogenesis of HD and whether their formation can be manipulated for therapeutic benefit.
Sathasivam
Kirupa
K
Department of Medical and Molecular Genetics, King's College London School of Medicine, King's College London, 8th Floor Tower Wing, Guy's Tower, Great Maze Pond, London, UK.
Lane
Amin
A
Legleiter
Justin
J
Warley
Alice
A
Woodman
Ben
B
Finkbeiner
Steve
S
Paganetti
Paolo
P
Muchowski
Paul J
PJ
Wilson
Stuart
S
Bates
Gillian P
GP
D000818:Animals; D001681:Biological Assay; D001921:Brain / Q000473:pathology* / Q000648:ultrastructure; D004195:Disease Models, Animal; D004591:Electrophoresis, Polyacrylamide Gel; D004797:Enzyme-Linked Immunosorbent Assay; D005091:Exons / Q000235:genetics; D055879:Gene Knock-In Techniques; D006816:Huntington Disease / Q000473:pathology*; D008024:Ligands; D051379:Mice; D018625:Microscopy, Atomic Force; D016253:Microscopy, Immunoelectron; D019600:Neuropil Threads / Q000473:pathology* / Q000648:ultrastructure; D010455:Peptides / Q000378:metabolism; D010641:Phenotype; D020836:Protein Structure, Quaternary; D050486:Serotonin Plasma Membrane Transport Proteins / Q000648:ultrastructure
D008024:Ligands; D010455:Peptides; D050486:Serotonin Plasma Membrane Transport Proteins; C493231:Slc6a4 protein, mouse; C097188:polyglutamine