title: Two different pathogenic mechanisms, dying-back axonal neuropathy and pancreatic senescence, are present in the YG8R mouse model of Friedreich's ataxia.
abstract: Frataxin (FXN) deficiency causes Friedreich's ataxia (FRDA), a multisystem disorder with neurological and non-neurological symptoms. FRDA pathophysiology combines developmental and degenerative processes of dorsal root ganglia (DRG), sensory nerves, dorsal columns and other central nervous structures. A dying-back mechanism has been proposed to explain the peripheral neuropathy and neuropathology. In addition, affected individuals have non-neuronal symptoms such as diabetes mellitus or glucose intolerance. To go further in the understanding of the pathogenic mechanisms of neuropathy and diabetes associated with the disease, we have investigated the humanized mouse YG8R model of FRDA. By biochemical and histopathological studies, we observed abnormal changes involving muscle spindles, dorsal root axons and DRG neurons, but normal findings in the posterior columns and brain, which agree with the existence of a dying-back process similar to that described in individuals with FRDA. In YG8R mice, we observed a large number of degenerated axons surrounded by a sheath exhibiting enlarged adaxonal compartments or by a thin disrupted myelin sheath. Thus, both axonal damage and defects in Schwann cells might underlie the nerve pathology. In the pancreas, we found a high proportion of senescent islets of Langerhans in YG8R mice, which decreases the β-cell number and islet mass to pathological levels, being unable to maintain normoglycemia. As a whole, these results confirm that the lack of FXN induces different pathogenic mechanisms in the nervous system and pancreas in the mouse model of FRDA: dying back of the sensory nerves, and pancreatic senescence.
authors.affiliation: Program in Rare and Genetic Diseases and IBV/CSIC Associated Unit at CIPF, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain CIBER de Enfermedades Raras (CIBERER), Valencia 28029, Spain.
authors.forename: Belén
authors.initials: B
authors.lastname: Mollá
authors.affiliation: Program in Rare and Genetic Diseases and IBV/CSIC Associated Unit at CIPF, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain CIBER de Enfermedades Raras (CIBERER), Valencia 28029, Spain.
authors.forename: Fátima
authors.initials: F
authors.lastname: Riveiro
authors.affiliation: Program in Rare and Genetic Diseases and IBV/CSIC Associated Unit at CIPF, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain Cell Therapy Program, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain.
authors.forename: Arantxa
authors.initials: A
authors.lastname: Bolinches-Amorós
authors.affiliation: Program in Rare and Genetic Diseases and IBV/CSIC Associated Unit at CIPF, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain CIBER de Enfermedades Raras (CIBERER), Valencia 28029, Spain.
authors.forename: Diana C
authors.initials: DC
authors.lastname: Muñoz-Lasso
authors.affiliation: Program in Rare and Genetic Diseases and IBV/CSIC Associated Unit at CIPF, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain CIBER de Enfermedades Raras (CIBERER), Valencia 28029, Spain Department of Genetic and Molecular Medicine, Institut de Recerca Pediàtrica Hospital San Joan de Déu, Barcelona 08950, Spain Department of Pediatrics, University of Barcelona School of Medicine, Barcelona 08036, Spain.
authors.forename: Francesc
authors.identifier: 0000-0002-8635-5421
authors.initials: F
authors.lastname: Palau
authors.affiliation: Program in Rare and Genetic Diseases and IBV/CSIC Associated Unit at CIPF, Centro de Investigación Príncipe Felipe (CIPF), Valencia 46012, Spain CIBER de Enfermedades Raras (CIBERER), Valencia 28029, Spain Department of Physiology, Faculty of Medicine and Dentistry, University of Valencia, Valencia 46010, Spain pilargc@uv.es.
authors.forename: Pilar
authors.initials: P
authors.lastname: González-Cabo
mesh_terms: D000375:Aging / Q000473:pathology*; D000818:Animals; D001369:Axons / Q000473:pathology*; D016922:Cellular Senescence; D004195:Disease Models, Animal; D004734:Energy Metabolism; D005621:Friedreich Ataxia / Q000235:genetics / Q000473:pathology*; D005727:Ganglia, Spinal / Q000473:pathology; D006801:Humans; D007328:Insulin / Q000378:metabolism; D000078790:Insulin Secretion; D050417:Insulin-Secreting Cells / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000378:metabolism; D009132:Muscles / Q000473:pathology; D009154:Mutation / Q000235:genetics*; D010084:Oxidation-Reduction; D010179:Pancreas / Q000473:pathology*; D017933:Peripheral Nervous System / Q000473:pathology
chemical_list: D007328:Insulin
keywords: Cell senescence; Dorsal root ganglia; Dying-back neuropathy; Friedreich’s ataxia; Islet of Langerhans; Muscle spindle