Weinhage Toni, Däbritz Jan, Brockhausen Anne, Wirth Timo, Brückner Markus, Belz Michael, Foell Dirk, Varga Georg
Department of Pediatric Rheumatology and Immunology, University Children's Hospital Münster, Münster, Germany.
Department of Pediatric Rheumatology and Immunology, University Children's Hospital Münster, Münster, Germany; The Royal Children's Hospital Melbourne, Murdoch Children's Research Institute, Gastrointestinal Research in Inflammation and Pathology, Parkville, Australia; Interdisciplinary Centre of Clinical Research, University of Münster, Münster, Germany; Department of Pediatrics, University of Melbourne, Melbourne Medical School, Parkville, Australia.
Cell Mol Gastroenterol Hepatol. 2015 May 6;1(4):433-449.e1. doi: 10.1016/j.jcmgh.2015.04.005. eCollection 2015 Jul.
BACKGROUND & AIMS: Granulocyte macrophage colony-stimulating factor (GM-CSF) treatment induces clinical response in patients with active Crohn's disease. To explore whether monocytes mediate GM-CSF effects in vivo, we used a mouse model of chronic colitis induced by dextran sulfate sodium (DSS).
Murine bone marrow-derived monocytes were activated with GM-CSF in vitro, and gene expression, phenotype, and function of GM-CSF-activated monocytes (GMaM) were analyzed. Therapeutic effects of GMaM were assessed in a model of chronic colitis induced by repeated cycles of DSS. Monocytes were administered intravenously and their immunomodulatory functions were evaluated in vivo by clinical monitoring, histology, endoscopy, immunohistochemistry, and expression of inflammatory markers in the colon. The distribution of injected monocytes in the intestine was measured by in vivo imaging.
GMaM expressed significantly higher levels of anti-inflammatory molecules. Production of reactive oxygen species was also increased while phagocytosis and adherence were decreased. GMaM up-regulated CD39 and CD73, which allows the conversion of adenosine triphosphate into adenosine and coincided with the induction of Foxp3 (forkhead-box-protein P3 positive) regulatory T cells (Treg) in cocultures of GMaM and naive T cells. In chronic DSS-induced colitis, adoptive transfer of GMaM led to significant clinical improvement, as demonstrated by reduced weight loss, inflammatory infiltration, ulceration, and colon shrinkage. As GMaM migrated faster and persisted longer in the inflamed intestine compared with control monocytes, their presence induced Treg generation in vivo.
GM-CSF leads to specific monocyte activation that modulates experimental colitis via mechanisms that include the induction of Treg. We demonstrate a possible mechanism of Treg induction through CD39 and CD73 expression on monocytes.
粒细胞巨噬细胞集落刺激因子（GM-CSF）治疗可使活动性克罗恩病患者产生临床反应。为探究单核细胞是否在体内介导GM-CSF的作用，我们使用了葡聚糖硫酸钠（DSS）诱导的慢性结肠炎小鼠模型。
体外使用GM-CSF激活小鼠骨髓来源的单核细胞，并分析GM-CSF激活的单核细胞（GMaM）的基因表达、表型和功能。在DSS重复诱导的慢性结肠炎模型中评估GMaM的治疗效果。静脉注射单核细胞，并通过临床监测、组织学、内镜检查、免疫组织化学以及结肠中炎症标志物的表达在体内评估其免疫调节功能。通过体内成像测量注射的单核细胞在肠道中的分布。
GMaM表达显著更高水平的抗炎分子。活性氧的产生也增加，而吞噬作用和黏附作用降低。GMaM上调CD39和CD73，这使得三磷酸腺苷转化为腺苷，并与GMaM和未活化T细胞共培养中Foxp3（叉头框蛋白P3阳性）调节性T细胞（Treg）的诱导同时发生。在慢性DSS诱导的结肠炎中，GMaM的过继转移导致显著的临床改善，表现为体重减轻、炎症浸润、溃疡和结肠收缩减少。与对照单核细胞相比，由于GMaM在发炎肠道中迁移更快且持续时间更长，它们的存在诱导了体内Treg的产生。
GM-CSF导致特定的单核细胞活化，通过包括诱导Treg在内的机制调节实验性结肠炎。我们证明了通过单核细胞上CD39和CD73表达诱导Treg的一种可能机制。
