MAPK pathway and B cells overactivation in multiple sclerosis revealed by phosphoproteomics and genomic analysis

Abstract

Dysregulation of signaling pathways in multiple sclerosis (MS) can be analyzed by phosphoproteomics in peripheral blood mononuclear cells (PBMCs). We performed in vitro kinetic assays on PBMCs in 195 MS patients and 60 matched controls and quantified the phosphorylation of 17 kinases using xMAP assays. Phosphoprotein levels were tested for association with genetic susceptibility by typing 112 single-nucleotide polymorphisms (SNPs) associated with MS susceptibility. We found increased phosphorylation of MP2K1 in MS patients relative to the controls. Moreover, we identified one SNP located in the PHDGH gene and another on IRF8 gene that were associated with MP2K1 phosphorylation levels, providing a first clue on how this MS risk gene may act. The analyses in patients treated with disease-modifying drugs identified the phosphorylation of each receptor’s downstream kinases. Finally, using flow cytometry, we detected in MS patients increased STAT1, STAT3, TF65, and HSPB1 phosphorylation in CD19+ cells. These findings indicate the activation of cell survival and proliferation (MAPK), and proinflammatory (STAT) pathways in the immune cells of MS patients, primarily in B cells. The changes in the activation of these kinases suggest that these pathways may represent therapeutic targets for modulation by kinase inhibitors.

Summary-data-based Mendelian randomization prioritizes potential druggable targets for multiple sclerosis

“…The potential utility of drugging the MAPK signalling pathway is clear from our study, with MAPK3, MAPK1 and MAP3K11 all prioritized in the primary analysis. Phosphoproteomic scans of differences in protein phosphorylation in people with multiple sclerosis have revealed constitutive high levels of activation of MAPK signalling in immune cells from people with multiple sclerosis ( Kotelnikova et al , 2019 ). Inhibitors of MEK1, a downstream target of MAPK signalling, have been trialled in Rheumatoid Arthritis, Crohn’s disease, psoriasis and multiple myeloma ( Arthur and Ley, 2013 ).…”

A validated generally applicable approach using the systematic assessment of disease modules by GWAS reveals a multi-omic module strongly associated with risk factors in multiple sclerosis

“…As we used GWAS enrichment as a selection criterion, the high GWAS enrichment of the final module was partly expected, which led us to analyze its biological functions and their potential epigenetic associations to MS. First, pathway enrichment analysis showed that the multi-omics module genes are significantly involved in several inter-linked immune-related pathways, most of which have been previously associated to MS, including the T cell receptor(Carbone et al 2014) (adjusted P = 3.6 x 10 -47 ), PI3K/Akt (Mammana et al 2018) (P = 4.6 x 10 -35 ), ErbB (Holley et al 2003) (P = 7.7 x 10 -32 ), Fc epsilon RI (Pedotti et al 2003) (P = 8.3 x 10 -30 ), chemokine (Cui et al 2020;Krumbholz et al 2006) (P = 2.6 x 10 -28 ), MAPK (Krementsov et al 2013;Kotelnikova et al 2019) (P = 2.0 x 10 -25 ), and B cell receptor (Kotelnikova et al 2019) (P = 3.9 x 10 -19 ) signaling pathways; Th17 (P = 9.6 x 10 -29 ), and Th1 and Th2 (P = 6.9 x 10 -19 ) cell differentiation (Kunkl et al 2020); natural killer cell mediated cytotoxicity (P = 1.6 x 10 -27 ); and leukocyte transendothelial migration (P = 3.9 x 10 -20 ), which indeed supports their relevance in MS. Interestingly, the module was also highly preprint (which was not certified by peer review) is the author/funder. All rights reserved.…”

Pre-clinical and Clinical Implications of “Inside-Out” vs. “Outside-In” Paradigms in Multiple Sclerosis Etiopathogenesis

“…With advances in technology, in addition to the traditional family history portion of a patient's medical record, further characterization of a patient's predisposition to disease can be evaluated by genomic sequencing. For example, recent studies have identified over 200 genomic and proteomic anomalies prevalent in the MS patient population, all directly or indirectly linked to the immune system (International Multiple Sclerosis Genetics Consortium et al, 2013;Manconi et al, 2018; International Multiple Sclerosis Genetics Consortium, 2019; Kotelnikova et al, 2019). Clinical presentation of the disease as well as chronic neuropathology highlight the destructive nature of the interaction between the immune system and the CNS.…”