Th132 - Single-cell Multi-omic Evaluation Reveals Differences in Metabolic Pathways Across B Cell Populations in Progression Toward Systemic Lupus Erythematosus

Miles Smith; Samantha Slight-Webb; Susan Macwana; Judith James; Joel Guthridge

Abstract Text: Background. Systemic Lupus Erythematosus (SLE) is an interferon-related autoimmune disease which the control of B cell signaling seems to be abnormal. Preclinical disease is characterized by autoantibody production and immune dysregulation, but only about 4-8% of anti-nuclear antibody positive individuals develop an autoimmune disease. Metabolic pathways play important role in B cells development and proliferation.
Methods. PBMCs from 32 subjects (ANA-, ANA+, incomplete lupus (ILE) and SLE patients) were sorted using NanoCellect Wolf microfluidic flow cytometer to remove dead and dying cells. Viable cells were tested in multi-omics single-cell analyses using 10X Genomics 5’ scRNA-seq/137-plex Total-seq multiomics using the 10X Chromium X fluidics system. Data were analyzed for distinct cluster identification and differential gene signatures in Python. Pathway analysis was performed in Ingenuity Pathway Analysis (IPA).
Results. Six distinct B cell clusters (Naïve, Activated Naïve, Transitional, Memory B cells, ABCs and plasma cells) were identified across all subjects. The proportion of cells varied by disease groups. Fractions of Naïve B cells were higher in ANA- controls and decreased moving toward disease development. Memory B cells are higher in ANA+. IPA analysis suggest the involvement of pathways related to oxidative phosphorylation (downregulated in ANA+; upregulated in SLE), apoptosis (upregulated in ANA+), PI3K signaling (upregulated in ANA+) and autophagy (downregulated in SLE).
Conclusions. We found differences in pathways associated with oxidative phosphorylation, autophagy and apoptosis in ANA+ individuals. These results suggest that dysregulation of those pathways might affect preclinical autoimmunity development trajectories.