ABSTRACT
OBJECTIVE: Alternative splicing is an important form of RNA processing that affects nearly all human genes. The differential expression of specific transcript and protein isoforms holds the potential of novel biomarkers for complex diseases. In this systematic review, we compiled the existing literature on aberrant alternative splicing events in multiple sclerosis (MS). METHODS: A systematic literature search in the PubMed database was carried out and supplemented by screening the reference lists of the identified articles. We selected only MS-related original research studies which compared the levels of different isoforms of human protein-coding genes. A narrative synthesis of the research findings was conducted. Additionally, we performed a case-control analysis using high-density transcriptome microarray data to reevaluate the genes that were examined in the reviewed studies. RESULTS: A total of 160 records were screened. Of those, 36 studies from the last two decades were included. Most commonly, peripheral blood samples were analyzed (32 studies), and PCR-based techniques were usually employed (27 studies) for measuring the expression of selected genes. Two studies used an exploratory genome-wide approach. Overall, 27 alternatively spliced genes were investigated. Nine of these genes appeared in at least two studies (CD40, CFLAR, FOXP3, IFNAR2, IL7R, MOG, PTPRC, SP140 and TNFRSF1A). The microarray data analysis confirmed differential alternative pre-mRNA splicing for 19 genes. CONCLUSIONS: An altered RNA processing of genes mediating immune signaling pathways has been repeatedly implicated in MS. The analysis of individual exon-level expression patterns is stimulated by the advancement of transcriptome profiling technologies. In particular, the examination of genes encoded in MS-associated genetic regions may provide important insights into the pathogenesis of the disease and help to identify new biomarkers.
Subject(s)
Alternative Splicing , Multiple Sclerosis/genetics , Gene Expression , HumansABSTRACT
AIMS: Fingolimod is a sphingosine-1-phosphate (S1P) receptor modulator approved for the treatment of the relapsing form of multiple sclerosis (MS). It prevents the egress of lymphocyte subpopulations from lymphoid tissues into the circulation. Here, we explored the broad effects of fingolimod on gene expression in different immune cell subsets. METHODS: Utilizing 150 high-resolution microarrays from Affymetrix, we obtained the transcriptome profiles of 5 cell populations, which were separated from the peripheral blood of MS patients prior to and following oral administration of fingolimod. RESULTS: After 3 months of treatment, significant transcriptome shifts were seen in CD4+ and CD8+ cells, which is mainly attributable to the selective homing of naive T cells and central memory T cells. Although the number of B cells was greatly reduced in the blood of fingolimod-treated MS patients, the analysis of differential expression in CD19+ cells identified only a small set of 42 genes, which indicated a slightly higher frequency of transitional B cells. The transcriptome signatures of CD14+ monocytes and CD56+ natural killer cells were not affected. CONCLUSION: Our study corroborates changes in the composition of circulating immune cells in response to fingolimod and delineates the respective implications at the RNA level. Our data may be valuable for comparing the effects of novel S1P receptor modulating agents, which may be a therapeutic option for patients with secondary progressive MS as well.
