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CD4+ T helper (TH)-17 cells play a pivotal role in mucosal immune defense and are implicated in autoimmune diseases and cancer. Although Th17 cell plasticity is well-studied in mice, the factors driving their transition between pro-inflammatory and immunomodulatory states in humans remain less understood. Our study explored the transcriptional and epigenetic landscapes of single-cell cultures of human memory TH17 cells, focusing on clones that produce either immunomodulatory IL-10 or pro-inflammatory IFN¦Ã and IL-22. We found that IL-10+ TH17 cells exhibit a T cell exhaustion-like profile with increased CTLA-4 expression and reduced IL-2 levels, while Ikaros zinc finger (IkZF) transcription factors, Aiolos and Eos, are differentially expressed in IL-10+ and IL-22+ TH17 cells, respectively. While exogenous IL-2 promotes IL-10 production in TH17 cells, lenalidomide induces IL-2 and promotes inflammatory TH17 cells, shifting TH17 cells towards a pro-inflammatory phenotype by reducing IL-10 and increasing IL-22 and IFN¦Ã levels. Conversely, upregulation of Eos enhanced pro-inflammatory cytokine production. These findings highlight the crucial role of IkZF transcription factors in regulating human TH17 cell functions. Moreover, single-cell RNA sequencing of PBMCs from lenalidomide-treated patients confirmed an enrichment of inflammatory signatures, including interferon and IL-2/STAT5 pathways in TH17 cells. The ability to modulate this axis through targeted interventions, such as lenalidomide-induced Aiolos degradation or enforced Eos expression, presents new therapeutic opportunities for managing TH17 cell states in cancer and autoimmune diseases.

BACKGROUND miR-155-5p is associated with autoimmune diseases. T helper 17 (Th17) cells, interleukin (IL)-17, and suppressor of cytokines signaling 1 (SOCS1) have important roles in the pathogenesis of systemic sclerosis (SSc). The purpose of this study was to explore the role of miR-155-5p in the regulation of IL-17 and SOCS1 expression in Th17 cells and the subsequent effect on SSc disease progression. METHODS Th17 cells were isolated from peripheral blood mononuclear cells of SSc patients and healthy controls (HCs). RT-qPCR and western blotting were used to examine the expression patterns of miR-155-5p, IL-17, and SOCS1. Luciferase reporter assays were performed to confirm SOCS1 as a target of miR-155-5p. RNA pull-down assays were performed to detect the interaction of IL-17 and SOCS1 with miR-155-5p. In situ hybridization was performed to analyze the co-expression pattern of miR-155-5p and IL17A in Th17 cells. RESULTS The levels of Th17 cell-derived miR-155-5p were significantly up-regulated in SSc patients compared with HCs, and its levels were negatively correlated with SOCS1?levels. Meanwhile, miR-155-5p positively regulated IL-17 expression levels in Th17 cells isolated from SSc patients as the disease progressed. Using pmirGLO vectors, SOCS1 was confirmed as a target of miR-155-5p. The binding status of IL-17 and SOCS1 to miR-155-5p was related to SSc progression. An increase in the co-localization of miR-155-5p and IL-17 was associated with greater SSc progression. CONCLUSIONS IL-17 and SOCS1 expression modulated by Th17 cell-derived miR-155-5p are critical for SSc progression, which may provide novel insights into the pathogenesis of SSc.