Multi-omics integration prioritizes potential drug targets for multiple sclerosis

Background and ObjectivesMultiple sclerosis (MS) is a chronic autoimmune disease with limited treatment options. Thus, drug discovery and repurposing are essential to enhance treatment efficacy and safety. MethodsWe obtained summary statistics for protein quantitative trait loci (pQTL) of 2,004 plasma proteins and 1,443 brain proteins, a genome-wide association study (GWAS) of MS susceptibility with 14,802 cases and 26,703 controls, and expression quantitative trait loci (eQTL) for 8,000 genes in peripheral blood and 16,704 genes in brain tissue. Our integrative analysis included a proteome-wide association study to identify MS-associated proteins, followed by summary-data-based Mendelian randomization (SMR) to determine causal associations. We used the HEIDI test and Bayesian colocalization analysis to distinguish pleiotropy from linkage. Proteins passing SMR, HEIDI, and colocalization analyses were considered potential drug targets. We further conducted pathway annotations, protein-protein interaction (PPI) network analysis, and examined mRNA levels of these targets. ResultsWe identified hundreds of MS-associated proteins in plasma and brain, confirming the causal roles of 18 proteins (nine in plasma and nine in brain). Among these, we found 78 annotated pathways and 16 existing non-MS drugs targeting six proteins. We also discovered intricate PPIs among seven potential drug targets and 19 existing MS drug targets, as well as PPIs of four targets across plasma and brain. Combining expression data, we identified two targets adhering to the central dogma of molecular biology. DiscussionWe prioritized 18 potential drug targets in plasma and brain, elucidating the underlying pathology and providing evidence for drug discovery and repurposing in MS.