Background: Throughout the inflammatory response that accompanies atherosclerosis, autoreactive CD4+T-helper cells accumulate in the atherosclerotic plaque. Apolipoprotein B100(apoB), the core protein of low-density lipoprotein, is an autoantigen that drives the generation of pathogenic T-helper type 1 (TH1) cells with proinflammatory cytokine secretion. Clinical data suggest the existence of apoB-specific CD4+T cells with an atheroprotective, regulatory T cell (Treg) phenotype in healthy individuals. Yet, the function of apoB-reactive Tregsand their relationship with pathogenic TH1 cells remain unknown. Methods: To interrogate the function of autoreactive CD4+T cells in atherosclerosis, we used a novel tetramer of major histocompatibility complex II to track T cells reactive to the mouse self-peptide apo B978-993(apoB+) at the single-cell level. Results: We found that apoB+T cells build an oligoclonal population in lymph nodes of healthy mice that exhibit a Treg-like transcriptome, although only 21% of all apoB+T cells expressed the Tregtranscription factor FoxP3 (Forkhead Box P3) protein as detected by flow cytometry. In single-cell RNA sequencing, apoB+T cells formed several clusters with mixed THsignatures that suggested overlapping multilineage phenotypes with pro- and anti-inflammatory transcripts of TH1, T helper cell type 2 (TH2), and T helper cell type 17 (TH17), and of follicular-helper T cells. ApoB+T cells were increased in mice and humans with atherosclerosis and progressively converted into pathogenic TH1/TH17-like cells with proinflammatory properties and only a residual Tregtranscriptome. Plaque T cells that expanded during progression of atherosclerosis consistently showed a mixed TH1/TH17 phenotype in single-cell RNA sequencing. In addition, we observed a loss of FoxP3 in a fraction of apoB+Tregsin lineage tracing of hyperlipidemic Apoe-/-mice. In adoptive transfer experiments, converting apoB+Tregsfailed to protect from atherosclerosis. Conclusions: Our results demonstrate an unexpected mixed phenotype of apoB-reactive autoimmune T cells in atherosclerosis and suggest an initially protective autoimmune response against apoB with a progressive derangement in clinical disease. These findings identify apoB autoreactive Tregsas a novel cellular target in atherosclerosis.
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- T-lymphocytes, regulatory
- apolipoprotein B-100
PubMed: MeSH publication types
- Journal Article