[Title]
Analysis of Single-Cell Transcriptome and Surface Protein Expression in Ankylosing Spondylitis Identifies OX40-Positive and Glucocorticoid-Induced Tumor Necrosis Factor Receptor-Positive Pathogenic Th17 Cells

[Author] 
Kijong Yi,1 Sungsin Jo,2 Woogil Song,3 Hae-In Lee,4 Hui-Ju Kim,4 Ji-Hyoun Kang,4 Seon Uk Kim,5 Seung Hoon Lee,2
Jinsung Park,2 Tae-Hwan Kim,6 Jeong Seok Lee,7 Eun Young Lee,5 and Tae-Jong Kim4

1 Kijong Yi, MD, PhD: Genome Insight, San Diego, California;
2 Sungsin Jo, PhD, Seung Hoon Lee, PhD, Jinsung Park, PhD: Hanyang University Institute for Rheumatology Research (HYIRR), Seoul, Republic of Korea;
3 Woogil Song, BS: Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Republic of Korea;
4 Hae-In Lee, MS, Hui-Ju Kim, MS, Ji-Hyoun Kang, MD, PhD, Tae-Jong Kim, MD, PhD: Department of Rheumatology, Chonnam National University Medical School and Hospital, Gwangju, Republic of Korea;
5 Seon Uk Kim, MS, Eun Young Lee, MD, PhD: Division of Rheumatology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea;
6 Tae-Hwan Kim, MD, PhD: Hanyang University Institute for Rheumatology Research and Department of Rheumatology, Hanyang University Hospital for Rheumatic Diseases, Seoul, Republic of Korea;
7 Jeong Seok Lee, MD, PhD: Genome Insight, San Diego, California, and Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology,
Daejeon, Republic of Korea.

[Journal] 

Arthritis & Rheumatology Volume75, Issue7, July 2023, Pages 1176-1186
 

[Abstract]

Objective

To demonstrate the immune landscape of blood and synovial cells in the setting of ankylosing spondylitis (AS) through the analysis of both single-cell transcriptome and surface protein expression, and to unveil the molecular characteristics of pathogenic Th17 cells.

Methods

This study included 40 individuals with active AS, 20 individuals with stable AS, 40 patients with active rheumatoid arthritis, and 20 healthy controls. Surface phenotype and intracellular staining were assessed using flow cytometry after peripheral blood mononuclear cells and synovial fluid mononuclear cells were stimulated with T cell receptor. Single-cell transcriptomes of 6 patients with active AS were studied along with cellular indexing of transcriptomes and epitopes by sequencing. We also assessed the outcome of targeting OX40 and glucocorticoid-induced tumor necrosis factor receptor (GITR) on the surface of Th17 cells in a mouse model of curdlan-injected SKG mice in which anti-GITR ligand and/or anti-OX40 ligand were used.

Results

We identified pathogenic Th17 cells as polyfunctional interleukin-17A (IL-17A)– and interferon-γ (IFNγ)–producing memory CD4+ T cells, with clinically supportive evidence for their pathogenic roles at sites of inflammation in AS. Transcriptome and flow cytometric analyses revealed that the coexpression of TNFRSF4 (OX40) and TNFRSF18 (GITR) is increased in pathogenic Th17 cells. Suppression of ligand receptor interactions in vivo through OX40 and GITR effectively suppressed clinical arthritis and decreased pathogenic Th17 cells in the curdlan-injected SKG mouse model.

Conclusion

Our results have implications for the understanding of pathogenic Th17 cells in AS patients and suggest potential therapeutic targets.