title: Dipeptide repeat proteins are present in the p62 positive inclusions in patients with frontotemporal lobar degeneration and motor neurone disease associated with expansions in C9ORF72.
abstract: BACKGROUND
  Cases of Frontotemporal Lobar Degeneration (FTLD) and Motor Neurone Disease (MND) associated with expansions in C9ORF72 gene are characterised pathologically by the presence of TDP-43 negative, but p62 positive, inclusions in granule cells of the cerebellum and in cells of dentate gyrus and area CA4 of the hippocampus.
  
  
  RESULTS
  We screened 84 cases of pathologically confirmed FTLD and 23 cases of MND for the presence of p62 positive inclusions in these three brain regions, and identified 13 positive cases of FTLD and 3 of MND. All cases demonstrated expansions in C9ORF72 by Southern blotting where frozen tissues were available. The p62 positive inclusions in both cerebellum and hippocampus were immunostained by antibodies to dipeptide repeat proteins (DPR), poly Gly-Ala (poly-GA), poly Gly-Pro (poly-GP) and poly Gly-Arg (poly-GR), these arising from a putative non-ATG initiated (RAN) sense translation of the GGGGCC expansion. There was also some slight, but variable, immunostaining with poly-AP antibody implying some antisense translation might also occur, though the relative paucity of immunostaining could reflect poor antigen avidity on the part of the antisense antibodies. Of the FTLD cases with DPR, 6 showed TDP-43 type A and 6 had TDP-43 type B histology; one had FTLD-tau with the pathology of corticobasal degeneration. There were no qualitative or quantitative differences in the pattern of immunostaining with antibodies to DPR, or p62, proteins between TDP-43 type A and type B cases. Ratings for frequency of inclusions immunostained by these poly-GA, poly-GP and poly-GR antibodies broadly correlated with those for immunolabelled by p62 antibody in all three regions.
  
  
  CONCLUSIONS
  We conclude that DPR are a major component of p62 positive inclusions in FTLD and MND.
authors.affiliation: Clinical and Cognitive Sciences Research Group, Institute of Brain, Behaviour and Mental Health, Faculty of Medical and Human Sciences, University of Manchester, Salford Royal Hospital, Salford M6 8HD, UK. david.mann@manchester.ac.uk.
authors.forename: David M A
authors.initials: DM
authors.lastname: Mann
authors.forename: Sara
authors.initials: S
authors.lastname: Rollinson
authors.forename: Andrew
authors.initials: A
authors.lastname: Robinson
authors.forename: Janis
authors.initials: J
authors.lastname: Bennion Callister
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Thompson
authors.forename: Julie S
authors.initials: JS
authors.lastname: Snowden
authors.forename: Tania
authors.initials: T
authors.lastname: Gendron
authors.forename: Leonard
authors.initials: L
authors.lastname: Petrucelli
authors.forename: Masami
authors.initials: M
authors.lastname: Masuda-Suzukake
authors.forename: Masato
authors.initials: M
authors.lastname: Hasegawa
authors.forename: Yvonne
authors.initials: Y
authors.lastname: Davidson
authors.forename: Stuart
authors.initials: S
authors.lastname: Pickering-Brown
mesh_terms: D000368:Aged; D015139:Blotting, Southern; D001921:Brain / Q000378:metabolism* / Q000502:physiology; D000073885:C9orf72 Protein; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D042622:DNA Repeat Expansion; D005260:Female; D057174:Frontotemporal Lobar Degeneration / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D002479:Inclusion Bodies / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D009474:Neurons / Q000378:metabolism / Q000473:pathology; D011506:Proteins / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000378:metabolism*
chemical_list: D000073885:C9orf72 Protein; C568651:C9orf72 protein, human; C118585:P62 protein, human; D011506:Proteins; D016601:RNA-Binding Proteins