Project description:BACKGROUND: Neonatal cerebellar cortical degeneration is a neurodegenerative disease described in several canine breeds including the Beagle. Affected Beagles are unable to ambulate normally from the onset of walking and the main pathological findings include Purkinje cell loss with swollen dendritic processes. Previous reports suggest an autosomal recessive mode of inheritance. The development of massively parallel sequencing techniques has presented the opportunity to investigate individual clinical cases using genome-wide sequencing approaches. We used genome-wide mRNA sequencing (mRNA-seq) of cerebellum tissue from a single Beagle with neonatal cerebellar cortical degeneration as a method of candidate gene sequencing, with the aim of identifying the causal mutation. RESULTS: A four-week old Beagle dog presented with progressive signs of cerebellar ataxia and the owner elected euthanasia. Histopathology revealed findings consistent with cerebellar cortical degeneration. Genome-wide mRNA sequencing (mRNA-seq) of RNA from cerebellum tissue was used as a method of candidate gene sequencing. After analysis of the canine orthologues of human spinocerebellar ataxia associated genes, we identified a homozygous 8 bp deletion in the ?-III spectrin gene, SPTBN2, associated with spinocerebellar type 5 in humans. Genotype analysis of the sire, dam, ten clinically unaffected siblings, and an affected sibling from a previous litter, showed the mutation to fully segregate with the disorder. Previous studies have shown that ?-III spectrin is critical for Purkinje cell development, and the absence of this protein can lead to cell damage through excitotoxicity, consistent with the observed Purkinje cell loss, degeneration of dendritic processes and associated neurological dysfunction in this Beagle. CONCLUSIONS: An 8 bp deletion in the SPTBN2 gene encoding ?-III spectrin is associated with neonatal cerebellar cortical degeneration in Beagle dogs. This study shows that mRNA-seq is a feasible method of screening candidate genes for mutations associated with rare diseases when a suitable tissue resource is available.
Project description:Progressive retinal atrophy (PRA) is a common cause of blindness in many pure and mixed breed dogs (Canis lupus familiaris). The typical onset of PRA begins with gradual night vision loss followed by day vision loss due to the death of rod and cone receptors, respectively. There are currently no mutations or genes reported to be causative or associated with PRA in the Hungarian Puli. In this study, we use an extensive list of 53 known PRA genes to screen for putative causal variants in this breed of dog.
Project description:Autosomal Recessive Spastic Ataxia of Charlevoix-Saguenay (ARSACS) is caused by mutations in SACS gene encoding sacsin. ARSACS patients and mouse models display early degeneration of cerebellum in agreement with high sacsin expression in this organ. We performed unbiased transcriptomic of cerebella from Sacs KO mice versus controls to dissect the mechanisms underlying cerebellar degeneration in ARSACS.
Project description:Australian working Kelpie dogs are known to be affected with an autosomal recessive form of inherited cerebellar ataxia (cerebellar abiotrophy, CA) that is characterised by a degeneration of Purkinje and granule cells in the cerebellar cortex. The clinical signs of CA include cerebellar ataxia, head tremor, motor in-coordination, wide based stance and high stepping gait, with varied clinical onset age. The clinical and pathological features are similar to cerebellar ataxias in humans. The genome-wide association study on a group of working Kelpies affected with the later onset form of CA identified a region on chromosome 9 to be strongly associated with the disease phenotype. Homozygosity analysis and whole genome sequencing identified a missense single nucleotide polymorphism, that segregated with the CA phenotype.
Project description:WWOX gene loss-of-function (LoF) has been associated with neuropathologies resulting in developmental, epileptic, and ataxic phenotypes of varying severity based on the level of WWOX dysfunction. WWOX gene biallelic germline variant p.Pro47Thr (P47T) has been causally associated with a new form of autosomal recessive cerebellar ataxia with epilepsy and intellectual disability (SCAR12). This mutation affects the WW1 protein binding domain of WWOX, impairing its ability to interact with canonical proline-proline-X-tyrosine motifs in partner proteins. We generated a mutant knock-in mouse model of Wwox P47T that phenocopies SCAR12. WwoxP47T/P47T mice displayed epilepsy, profound social behavior and cognition deficits, and poor motor coordination. These deficits progressed with age, and mice became practically immobile, suggesting severe cerebellar dysfunction. WwoxP47T/P47T mice exhibited signs of progressive neuroinflammation with elevated astro-microgliosis that increased with age. The cerebellar cortex displayed significantly reduced molecular and granular layer thickness and a strikingly reduced number of Purkinje cells with degenerated dendrites. Transcriptome profiling from various brain regions from these Wwox LoF mice highlighted widespread changes in neuronal and glial pathways, enrichment of bioprocesses related to neuroinflammation and severe cerebellar dysfunction, activation of pathways compatible with compensatory neurogenesis along with major suppression of gene networks associated with neuronal cell differentiation and brain development. Our results show significant pathobiological effects and potential mechanisms through which Wwox LoF leads to cerebellar neurodegeneration, neuroinflammation, and ataxia.
Project description:Viromes of sour and sweet cherry trees in Hungarian germ line collections were surveyed using small RNA HTS as an unbiased method. RNA from leaf samples of different cultivars were purified and used to produce seven pools from which small RNA HTS libraries were prepared. The sequenced reads were analyzed using bioinformatic methods to revel the presence of viruses in the samples. Presence of the viruses were validated using RT-PCR.
Project description:Human induced pluripotent stem cells (iPSCs) have great potential for disease modeling. However, generating iPSC-derived models to study brain diseases remains a challenge. In particular, the ability to recapitulate cerebellar development in vitro is still limited. We presented for the first time a reproducible and scalable production of cerebellar organoids by using the novel Vertical-Wheel single-use bioreactors, in which functional cerebellar neurons were obtained. Here, we evaluate the global gene expression profiles by RNA sequencing (RNA-seq) across cerebellar differentiation, demonstrating a faster cerebellar commitment in this novel dynamic differentiation protocol. Furthermore, transcriptomic profiles suggest a significant enrichment of extracellular matrix (ECM) in dynamic-derived cerebellar organoids, which can better mimic the neural microenvironment and support a consistent neuronal network. The presence of factors that favors angiogenesis onset was detected in dynamic condition, which can enhance functional maturation of cerebellar organoids. We anticipate that large-scale production of cerebellar organoids may help developing models for drug screening, toxicological tests and studying pathological pathways involved in cerebellar degeneration.