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Abstract：
OBJECTIVE: 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).
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
METHODS: 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.
RESULTS: 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.
CONCLUSIONS: 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.
摘要：
目的：粒细胞巨噬细胞集落刺激因子（GM-CSF）治疗可诱导活动性克罗恩病患者的临床反应。探讨单核细胞是否在体内介导GM-CSF的作用，我们使用葡聚糖硫酸钠（DSS）诱导的小鼠慢性结肠炎模型。
方法：体外用GM-CSF活化小鼠骨髓源性单核细胞，和基因表达，表型,并对GM-CSF激活的单核细胞(GMaM)进行功能分析。在由DSS的重复周期诱导的慢性结肠炎模型中评估GMaM的治疗效果。单核细胞静脉内给药，并通过临床监测在体内评估其免疫调节功能，组织学,内窥镜检查,免疫组织化学，和结肠中炎症标志物的表达。通过体内成像测量肠内注射的单核细胞的分布。
结果：GMaM表达显著更高水平的抗炎分子。活性氧的产生也增加，而吞噬作用和粘附性降低。GMaM上调CD39和CD73，这允许三磷酸腺苷转化为腺苷，并且与GMaM和幼稚T细胞共培养物中Foxp3+（叉头盒蛋白P3阳性）调节性T细胞（Treg）的诱导相吻合。在慢性DSS诱导的结肠炎中，GMaM的过继转移导致了显著的临床改善，正如体重减轻所证明的那样，炎性浸润,溃疡,和结肠收缩。与对照单核细胞相比，GMaM在发炎的肠道中迁移更快，持续更长的时间，它们的存在诱导体内Treg的产生。
结论：GM-CSF导致特异性单核细胞活化，通过包括诱导Treg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的可能机制。
方法：体外用GM-CSF活化小鼠骨髓源性单核细胞，和基因表达，表型,并对GM-CSF激活的单核细胞(GMaM)进行功能分析。在由DSS的重复周期诱导的慢性结肠炎模型中评估GMaM的治疗效果。单核细胞静脉内给药，并通过临床监测在体内评估其免疫调节功能，组织学,内窥镜检查,免疫组织化学，和结肠中炎症标志物的表达。通过体内成像测量肠内注射的单核细胞的分布。
结果：GMaM表达显著更高水平的抗炎分子。活性氧的产生也增加，而吞噬作用和粘附性降低。GMaM上调CD39和CD73，这允许三磷酸腺苷转化为腺苷，并且与GMaM和幼稚T细胞共培养物中Foxp3+（叉头盒蛋白P3阳性）调节性T细胞（Treg）的诱导相吻合。在慢性DSS诱导的结肠炎中，GMaM的过继转移导致了显著的临床改善，正如体重减轻所证明的那样，炎性浸润,溃疡,和结肠收缩。与对照单核细胞相比，GMaM在发炎的肠道中迁移更快，持续更长的时间，它们的存在诱导体内Treg的产生。
结论：GM-CSF导致特异性单核细胞活化，通过包括诱导Treg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的可能机制。
