Wayne State University School of Medicine
Institute of Environmental Health Sciences

Author Of 1 Presentation

Pathogenesis – Immunology Poster Presentation

P0966 - How Do Exosome Enriched Fractions from Multiple Sclerosis Patients Cultured B Cells Kill Oligodendroglia (ID 922)

Speakers
Presentation Number
P0966
Presentation Topic
Pathogenesis – Immunology

Abstract

Background

Background: B cells mediate patho­genesis in multi­ple sclerosis (MS) by mecha­nisms unrelated to immuno­globulin (Ig) pro­duction. Supernatants (Sup) from cultured MS B cells but not controls are cyto­toxic to oligo­dendro­cytes (OL) and neurons (Lisak et al. 2012, 2017). Killing is inde­pen­dent of complement, and does not cor­rel­ate with Sup levels of IgG, IgM or cyto­kines tested. Death of OL and neurons involves apoptosis (Lisak et al. 2017) and is mediated by factors in exosome-enriched fractions (Ex-En) (Benjamins et al. 2019).

Objectives

Objective: To investigate how Ex-En released by cultured unstimulated peripheral blood B cells from MS patients kill OL.

Methods

Methods: B cells were cultured in exosome-depleted serum-free medium. Ex-En were prepared from Sup by ultracentrifugation. Sup or Ex-En were diluted 1:4 with OL culture medium and tested for toxicity on rat OL. Proteomic analysis was performed on Sup and Ex-En.

Results

Results: MS B cell Sup kill OL primarily by caspase-dependent pathways and are toxic to OL in both mixed glial and OL-enriched cultures, suggesting direct action on OL. Toxicity is reduced by activation of melanocortin and sigma-1 receptors, implicating cAMP and IP3 pathways in protection. We developed methods for reliable proteomic analysis of the low amounts of protein in Ex-En, and a strategy for RNASeq, lipidomic and integrated bioinformatic analyses. Feasibility studies in progress will give a sample-size estimate based on analysis of variability for detection of significant differences between MS and control.

Conclusions

Conclusions: A multi-omics approach may allow identification of candidates responsible for toxicity to OL in Ex-En from MS B cells.

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