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- Agler, Caryline, et al.
(författare)
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Canine Hereditary Ataxia in Old English Sheepdogs and Gordon Setters Is Associated with a Defect in the Autophagy Gene Encoding RAB24
- 2014
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Ingår i: PLOS Genetics. - : Public Library of Science (PLoS). - 1553-7390 .- 1553-7404. ; 10:2, s. e1003991-
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Tidskriftsartikel (refereegranskat)abstract
- Old English Sheepdogs and Gordon Setters suffer from a juvenile onset, autosomal recessive form of canine hereditary ataxia primarily affecting the Purkinje neuron of the cerebellar cortex. The clinical and histological characteristics are analogous to hereditary ataxias in humans. Linkage and genome-wide association studies on a cohort of related Old English Sheepdogs identified a region on CFA4 strongly associated with the disease phenotype. Targeted sequence capture and next generation sequencing of the region identified an A to C single nucleotide polymorphism (SNP) located at position 113 in exon 1 of an autophagy gene, RAB24, that segregated with the phenotype. Genotyping of six additional breeds of dogs affected with hereditary ataxia identified the same polymorphism in affected Gordon Setters that segregated perfectly with phenotype. The other breeds tested did not have the polymorphism. Genome-wide SNP genotyping of Gordon Setters identified a 1.9 MB region with an identical haplotype to affected Old English Sheepdogs. Histopathology, immunohistochemistry and ultrastructural evaluation of the brains of affected dogs from both breeds identified dramatic Purkinje neuron loss with axonal spheroids, accumulation of autophagosomes, ubiquitin positive inclusions and a diffuse increase in cytoplasmic neuronal ubiquitin staining. These findings recapitulate the changes reported in mice with induced neuron-specific autophagy defects. Taken together, our results suggest that a defect in RAB24, a gene associated with autophagy, is highly associated with and may contribute to canine hereditary ataxia in Old English Sheepdogs and Gordon Setters. This finding suggests that detailed investigation of autophagy pathways should be undertaken in human hereditary ataxia. Author Summary Neurodegenerative diseases are one of the most important causes of decline in an aging population. An important subset of these diseases are known as the hereditary ataxias, familial neurodegenerative diseases that affect the cerebellum causing progressive gait disturbance in both humans and dogs. We identified a mutation in RAB24, a gene associated with autophagy, in Old English Sheepdogs and Gordon Setters with hereditary ataxia. Autophagy is a process by which cell proteins and organelles are removed and recycled and its critical role in maintenance of the continued health of cells is becoming clear. We evaluated the brains of affected dogs and identified accumulations of autophagosomes within the cerebellum, suggesting a defect in the autophagy pathway. Our results suggest that a defect in the autophagy pathway results in neuronal death in a naturally occurring disease in dogs. The autophagy pathway should be investigated in human hereditary ataxia and may represent a therapeutic target in neurodegenerative diseases.
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| 2. |
- Thomas, Rachael, et al.
(författare)
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Genomic profiling reveals extensive heterogeneity in somatic DNA copy number aberrations of canine hemangiosarcoma
- 2014
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Ingår i: Chromosome Research. - : Springer Science and Business Media LLC. - 0967-3849 .- 1573-6849. ; 22:3, s. 305-319
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Tidskriftsartikel (refereegranskat)abstract
- Canine hemangiosarcoma is a highly aggressive vascular neoplasm associated with extensive clinical and anatomical heterogeneity and a grave prognosis. Comprehensive molecular characterization of hemangiosarcoma may identify novel therapeutic targets and advanced clinical management strategies, but there are no published reports of tumor-associated genome instability and disrupted gene dosage in this cancer. We performed genome-wide microarray-based somatic DNA copy number profiling of 75 primary intra-abdominal hemangiosarcomas from five popular dog breeds that are highly predisposed to this disease. The cohort exhibited limited global genomic instability, compared to other canine sarcomas studied to date, and DNA copy number aberrations (CNAs) were predominantly of low amplitude. Recurrent imbalances of several key cancer-associated genes were evident; however, the global penetrance of any single CNA was low and no distinct hallmark aberrations were evident. Copy number gains of dog chromosomes 13, 24, and 31, and loss of chromosome 16, were the most recurrent CNAs involving large chromosome regions, but their relative distribution within and between cases suggests they most likely represent passenger aberrations. CNAs involving CDKN2A, VEGFA, and the SKI oncogene were identified as potential driver aberrations of hemangiosarcoma development, highlighting potential targets for therapeutic modulation. CNA profiles were broadly conserved between the five breeds, although subregional variation was evident, including a near twofold lower incidence of VEGFA gain in Golden Retrievers versus other breeds (22 versus 40 %). These observations support prior transcriptional studies suggesting that the clinical heterogeneity of this cancer may reflect the existence of multiple, molecularly distinct subtypes of canine hemangiosarcoma.
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