Article
Differential expression and regulation of complement receptors C5aR1 and C5aR2 in T cells of granulomatosis with polyangiitis: Implications for disease pathophysiology
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Authors
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Solveig Augustin
- Universität zu Lübeck, Klinik für Rheumatologie und klinische Immunologie, Lübeck
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Anja Stähle
- Universität zu Lübeck, Klinik für Rheumatologie und klinische Immunologie, Lübeck
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Sebastian Klapa
- Universität zu Lübeck, Klinik für Rheumatologie und klinische Immunologie, Lübeck
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Nadja Leinung
- Universität zu Lübeck, Klinik für Rheumatologie und klinische Immunologie, Lübeck
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Silke Pitann
- Universität zu Lübeck, Klinik für Rheumatologie und klinische Immunologie, Lübeck
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Antje Müller
- Universität zu Lübeck, Klinik für Rheumatologie und klinische Immunologie, Lübeck
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Peter Lamprecht
- Universität zu Lübeck, Klinik für Rheumatologie und klinische Immunologie, Lübeck
| Published: | September 18, 2024 |
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Outline
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Methods: We conducted transcriptomic analysis of sorted CD4+ and CD8+ T cells isolated from GPA patients (n=3) and healthy controls (n=3) to identify differentially expressed genes. In addition, we performed Gene Ontology (GO) analysis for functional insights. Intra- and extracellular C5aR1 and C5aR2 T cell expression from GPA patients (n=5) and controls (n=5) was determined by flow cytometry. T cells isolated by magnetic cell separation were subjected to in vitro stimulation for 48 h mimicking antigen-stimulation (CD3 +/- CD28) in the presence or absence of C5a +/- C5aR1 inhibition to assess functional responses. Gene expression levels of C5AR1 and C5AR2 were measured by PCR, while the secretion of IFN-gamma and IL-17 from cell supernatants was determined by ELISA.
Results: In this study, we identified a distinct gene expression profile in GPA T cells, including complosome components IL1β, IL18, NLRP3, and C5aR1. In addition, we found low intracellular expression of C5aR1 in all CD4+ and CD8+ T cells. By contrast, intracellular C5aR2 expression was increased in CD4+ and CD8+ T cells in GPA. Moreover, CD8 T cells displayed an increased extracellular C5aR2 expression in GPA. Contrasting with GPA, C5AR1 and C5AR2 gene expression was down-regulated upon T cell receptor activation without co-stimulation in controls. CD3 and CD28 T cell stimulation significantly enhanced IFN-gamma secretion in GPA and was not further increased by C5a. IL-17 secretion was increased in GPA patients even in absence of antigenic stimulation and was abrogated by C5aR inhibition.
Conclusion: Our study provides evidence for the involvement of the “complosome” in the pathophysiology of GPA, highlighting a distinct regulation of C5aR1 and C5aR2 in GPA T cells. Our findings suggest that C5a receptors participate in modulating cellular Th1 and Th17 responses in GPA unveiling novel aspects of immune dysregulation in autoimmune vasculitis.
Disclosure: None.
References
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