bims-maitce 2024-10-13 papers

Issue of 2024–10–13
two papers selected by
Andy E. Hogan, Maynooth University

BMC Oral Health. 2024 Oct 05. 24(1): 1183

Circulating mucosal-associated invariant T cell alterations in adults with recent-onset and long-term oral lichen planus.

Xiaoli Wu, Siting Chen, Yinshen Yang, Xiaoheng Xu, Xiaoqin Xiong, Wenxia Meng.

BACKGROUND: Mucosal-associated invariant T (MAIT) cells play key roles in many inflammatory diseases. However, their effects on the long-term course of oral lichen planus (OLP) and recent-onset OLP remain unclear. In this study, we aimed to investigate the function of MAIT cells in the different processes of OLP and to explore the immunological background of this disease.
METHODS: The frequency, phenotype, cytokine secretion, and clinical relevance of MAIT cells were investigated. MAIT cells were collected from the peripheral blood of 14 adults with recent-onset OLP (7-120 days after disease onset) and 16 adults with long-term course OLP (>2 years after diagnosis) using flow cytometry and compared with 15 healthy blood donors. Statistical analyses were performed using the GraphPad Prism software.
RESULTS: MAIT cells from adults with recent-onset OLP exhibited an activated phenotype, as indicated by an increased frequency of CD69+ (p < 0.05) and CD38+MAIT cells (p < 0.01) and elevated production of the proinflammatory cytokine IL-17 A (p < 0.01), compared with healthy adult donors. In adults with long-term OLP, MAIT cells exhibited an activated and exhausted phenotype, characterized by high expression of CD69 (p < 0.01) and PD-1 (p < 0.001) and increased production of granzyme B released (p < 0.01). Compared with recent-onset OLP patients, long-term OLP patients showed a decreased production of CD8+, and CD4-CD8- cells, but an increase in PD-1+ production (p < 0.05).
CONCLUSIONS: Circulating MAIT cells exhibited activation in OLP patients across varying disease durations. Given that PD-1 expression is elevated in adults with long-term OLP, it is reasonable to infer that circulating MAIT cells in long-term OLP may exhibit a more exhausted state than those in recent-onset OLP.

Keywords: Functional profile; Immunoregulatory activity; Mucosal-associated invariant T cells (MAIT cells); Oral lichen planus (OLP); Phenotypes

DOI: https://doi.org/10.1186/s12903-024-04959-3

Front Immunol. 2024 ;15 1448717

Epigenetic regulation in epithelial cells and innate lymphocyte responses to S. Typhi infection: insights into IFN-γ production and intestinal immunity.

Rosângela Salerno-Goncalves, Haiyan Chen, Andrea C Bafford, Marcelo B Sztein.

Infection by Salmonella enterica serovar Typhi (S. Typhi), the cause of enteric fevers, is low in high-income countries but persistent in low- and middle-income countries, resulting in 65,400-187,700 deaths yearly. Drug resistance, including in the United States, exacerbates this issue. Evidence indicates that innate lymphocytes (INLs), such as natural killer (NK) cells, and unconventional T lymphocytes (e.g., Mucosal-associated invariant T (MAIT) cells and T-cell receptor gamma delta (TCR-γδ) cells) can impact the intestinal epithelial barrier, the primary site of exposure to S. Typhi. Moreover, INL production of IFN-γ is central in controlling S. Typhi infection. However, the impact of epithelial cells (EC) on the secretion of IFN-γ by INLs and the relationship between these events and epigenetic changes remains unknown. Epigenetic modifications in host cells are fundamental for their differentiation and function, including IFN-γ production. Herein, using a human organoid-derived polarized intestinal epithelial cell monolayer, we investigated the role of H3K4me3 and H3K27me3 epigenetic marks in intestinal immunity, focusing on the function of EC, NK, MAIT, and TCR-γδ cells in response to S. Typhi. This study builds on our previous findings that MAIT subsets exhibiting specific IFN-γ pattern signatures were associated with protection against typhoid fever and that S. Typhi infection regulates changes in chromatin marks that depend on individual cell subsets. Here, we show that cultures exposed to S. Typhi without EC exhibit a significant increase in NK and MAIT cells, and, to a lesser extent, TCR-γδ cells, expressing IFN-γ and H3K4me3 but not H3K27me3 marks, contrasting with cultures where EC is present. The influence of EC on INL H3K4me3 marks might be indirectly mediated through the modulation of IL-18 secretion via the Histone Deacetylase 6 gene during S. Typhi infection.

Keywords: bacteria; epigenetic; gut; human; salmonella

DOI: https://doi.org/10.3389/fimmu.2024.1448717