Schimpel Christa, Passegger Christina, Tam-Amersdorfer Carmen, Strobl Herbert
Division of Immunology, Otto Loewi Research Center for Vascular Biology, Immunology and Inflammation, Medical University of Graz, 8010 Graz, Austria.
Cells. 2025 Aug 22;14(17):1300. doi: 10.3390/cells14171300.
Retinoic acid (RA) plays a key role in mucosal immune regulation and tolerance, with implications for inflammatory bowel disease (IBD). However, its effects have not been extensively studied in humanized in vitro models that recapitulate epithelial-immune interactions. We established a 3D in vitro small intestinal model composed of three epithelial cell types, naïve CD4 T cells, and monocyte/dendritic cell (M/DC) precursors derived from CD34 umbilical cord blood hematopoietic stem/progenitor cells. The epithelial microenvironment strongly suppressed monocyte/DC differentiation and T cell activation, indicating a regulatory role of epithelial-derived signals. Retinoic acid (RA) priming of M/DC precursors induced CD103CD11bSirp1α regulatory DCs and promoted a shift from naive to memory-type T cells. Upon addition of pro-inflammatory cytokines (TNF-α, IFN-γ, IL-1β), the model mimicked an inflamed intestinal state, resulting in CD14CD16 inflammatory monocytes and increased T cell activation (CD25CD69). RA-primed DCs modestly counterbalanced T cell activation and IBD-like responses, even under inflammatory conditions. Flow cytometry and clustering analysis revealed distinct immune cell phenotypes depending on RA exposure and cytokine context. This model provides a reproducible and physiologically relevant human system to study RA-mediated immune programming in the intestinal mucosa and may support the development of novel therapeutic strategies for IBD and related inflammatory conditions. Statistical differences were evaluated using ANOVA with Tukey's post-hoc test ( = 4; < 0.05).
维甲酸（RA）在黏膜免疫调节和耐受中起关键作用，对炎症性肠病（IBD）有影响。然而，其作用在模拟上皮-免疫相互作用的人源化体外模型中尚未得到广泛研究。我们建立了一种三维体外小肠模型，该模型由三种上皮细胞类型、初始CD4 T细胞以及源自CD34脐带血造血干/祖细胞的单核细胞/树突状细胞（M/DC）前体组成。上皮微环境强烈抑制单核细胞/树突状细胞分化和T细胞活化，表明上皮衍生信号具有调节作用。用维甲酸（RA）预处理M/DC前体可诱导产生CD103⁺CDllb⁻Sirp1α⁺调节性树突状细胞，并促进T细胞从初始型向记忆型转变。加入促炎细胞因子（TNF-α、IFN-γ、IL-1β）后，该模型模拟了炎症性肠状态，导致产生CD14⁺CD16⁺炎性单核细胞并增加T细胞活化（CD25⁺CD69⁺）。即使在炎症条件下，经RA预处理的树突状细胞也适度地平衡了T细胞活化和IBD样反应。流式细胞术和聚类分析揭示了取决于RA暴露和细胞因子环境的不同免疫细胞表型。该模型提供了一个可重复且与生理相关的人体系统，用于研究RA介导的肠道黏膜免疫编程，并可能支持开发针对IBD和相关炎症性疾病的新型治疗策略。使用方差分析和Tukey事后检验评估统计学差异（n = 4；P < 0.05）。
