Transcriptomic insights into Multiple System Atrophy from a PLP-a-Synuclein transgenic mouse model
Multiple system atrophy (MSA) is a rare, neurodegenerative disorder with rapid motor and non-motor symptom progression. MSA is characterized by protein aggregations of a-synuclein found in the cytoplasm of oligodendrocytes. Despite this pathological hallmark, there is still little known about the cause of this disease, resulting in poor treatment options and quality of life post-diagnosis. In this study, we investigated differentially expressed genes via RNA-sequencing of brain samples from a validated PLP-a-synuclein transgenic mouse model, identifying a total of 40 DEGs in the MSA group compared to control, with top detected genes being Gm15446, Mcm6, Aldh7a1 and Gm3435. We observed a significant enrichment of immune pathways and endothelial cell genes among the upregulated genes, whereas downregulated genes were significantly enriched for oligodendrocyte and neuronal genes. We then calculated possible overlap of these DEGs with previously profiled human MSA RNA, resulting in the identification of significant downregulation of the Tsr2 gene. Identifying key gene expression profiles specific to MSA patients is crucial to further understanding the cause, and possible prevention, of this rapidly progressive neurodegenerative disorder. Overall design: Homozygous male and female transgenic PLP-a-synuclein mice (MGI:3604008) overexpressing human a-synuclein under the PLP promoter and age- and sex-matched non-transgenic C57Bl/6 background mice were used in this study. All animals were bred and housed in a temperature-controlled room under a 12/12 hour dark/light cycle, with free access to food and water and under special pathogen free conditions in the animal facility of the Medical University of Innsbruck. The experiments were performed in accordance with the Austrian law under permission BMWFW-66.011/0125-WF/V/3b/2015 and BMWF-66.011/0120-II/3b/2013. At the age of 12 months, mice were sacrificed under overdose of thiopental, brains were extracted, each hemisphere was snap frozen in liquid nitrogen, and kept at -80°C until further processing. RNA was isolated from hemisphere samples using the RNeasy Kit (Qiagen). Sequencing libraries were prepared with 250 ng of total RNA using Illumina Stranded Total RNA with Ribo-Zero Plus library preparation (Illumina Inc). PCR-enriched fragments were validated on a 2200 TapeStation (Agilent Technologies) and quantitated via qPCR. The final library was sequenced by 100 bp paired-end sequencing on a HiSeq 2500 (Illumina) at the Collaborative Sequencing Center (Translational Genomics Research Institute, Phoenix, AZ).