Assessment of PABPN1 nuclear inclusions on a large cohort of patients and in a human xenograft model of oculopharyngeal muscular dystrophy

Fanny Roth, Jamila Dhiab, Alexis Boulinguiez, Hadidja Rose Mouigni, Saskia Lassche, Elisa Negroni, Laura Muraine, Alix Marhic, Alison Oliver, Jeanne Lainé, Andrée Rouche, Erin K. O’Ferrall, Baziel van Engelen, Coen Ottenheijm, Hagar Greif, Sergiu Blumen, Jean Lacau St Guily, Sophie Perie, Gillian Butler-Browne, Vincent MoulyCapucine Trollet

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

Oculopharyngeal muscular dystrophy (OPMD) is a rare muscle disease characterized by an onset of weakness in the pharyngeal and eyelid muscles. The disease is caused by the extension of a polyalanine tract in the Poly(A) Binding Protein Nuclear 1 (PABPN1) protein leading to the formation of intranuclear inclusions or aggregates in the muscle of OPMD patients. Despite numerous studies stressing the deleterious role of nuclear inclusions in cellular and animal OPMD models, their exact contribution to human disease is still unclear. In this study, we used a large and unique collection of human muscle biopsy samples to perform an in-depth analysis of PABPN1 aggregates in relation to age, genotype and muscle status with the final aim to improve our understanding of OPMD physiopathology. Here we demonstrate that age and genotype influence PABPN1 aggregates: the percentage of myonuclei containing PABPN1 aggregates increases with age and the chaperone HSP70 co-localize more frequently with PABPN1 aggregates with a larger polyalanine tract. In addition to the previously described PRMT1 and HSP70 co-factors, we identified new components of PABPN1 aggregates including GRP78/BiP, RPL24 and p62. We also observed that myonuclei containing aggregates are larger than myonuclei without. When comparing two muscles from the same patient, a similar amount of aggregates is observed in different muscles, except for the pharyngeal muscle where fewer aggregates are observed. This could be due to the peculiar nature of this muscle which has a low level of PAPBN1 and contains regenerating fibers. To confirm the fate of PABPN1 aggregates in a regenerating muscle, we generated a xenograft model by transplanting human OPMD muscle biopsy samples into the hindlimb of an immunodeficient mouse. Xenografts from subjects with OPMD displayed regeneration of human myofibers and PABPN1 aggregates were rapidly present—although to a lower extent-after muscle fiber regeneration. Our data obtained on human OPMD samples add support to the dual non-exclusive models in OPMD combining toxic PABPN1 intranuclear inclusions together with PABPN1 loss of function which altogether result in this late-onset and muscle selective disease.

Original languageEnglish (US)
Pages (from-to)1157-1170
Number of pages14
JournalActa Neuropathologica
Volume144
Issue number6
DOIs
StatePublished - Dec 2022
Externally publishedYes

Keywords

  • Human biopsies
  • Inclusions
  • Loss of function
  • Nuclear aggregates
  • OPMD
  • PABPN1
  • Xenograft

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Clinical Neurology
  • Cellular and Molecular Neuroscience

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