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Abstract：
BACKGROUND: Novel therapeutic strategies are urgently needed for Mycobacterium avium complex pulmonary disease (MAC-PD). Human mesenchymal stromal cells (MSCs) can directly inhibit MAC growth, but their effect on intracellular bacilli is unknown. We investigated the ability of human MSCs to reduce bacterial replication and inflammation in MAC-infected macrophages and in a murine model of MAC-PD.
METHODS: Human monocyte-derived macrophages (MDMs) were infected with M. avium Chester strain and treated with human bone marrow-derived MSCs. Intracellular and extracellular colony-forming units (CFUs) were counted at 72 hours. Six-week-old female balb/c mice were infected by nebulisation of M. avium Chester. Mice were treated with 1×106 intravenous human MSCs or saline control at 21 and 28 days post-infection. Lungs, liver and spleen were harvested 42 days post-infection for bacterial counts. Cytokines were quantified by ELISA.
RESULTS: MSCs reduced intracellular bacteria in MDMs over 72 hours (median 35% reduction, p=0.027). MSC treatment increased extracellular concentrations of prostaglandin E2 (PGE2) (median 10.1-fold rise, p=0.002) and reduced tumour necrosis factor-α (median 28% reduction, p=0.025). Blocking MSC PGE2 production by cyclo-oxygenase-2 (COX-2) inhibition with celecoxib abrogated the antimicrobial effect, while this was restored by adding exogenous PGE2. MSC-treated mice had lower pulmonary CFUs (median 18% reduction, p=0.012), but no significant change in spleen or liver CFUs compared with controls.
CONCLUSIONS: MSCs can modulate inflammation and reduce intracellular M. avium growth in human macrophages via COX-2/PGE2 signalling and inhibit pulmonary bacterial replication in a murine model of chronic MAC-PD.
METHODS: Human monocyte-derived macrophages (MDMs) were infected with M. avium Chester strain and treated with human bone marrow-derived MSCs. Intracellular and extracellular colony-forming units (CFUs) were counted at 72 hours. Six-week-old female balb/c mice were infected by nebulisation of M. avium Chester. Mice were treated with 1×106 intravenous human MSCs or saline control at 21 and 28 days post-infection. Lungs, liver and spleen were harvested 42 days post-infection for bacterial counts. Cytokines were quantified by ELISA.
RESULTS: MSCs reduced intracellular bacteria in MDMs over 72 hours (median 35% reduction, p=0.027). MSC treatment increased extracellular concentrations of prostaglandin E2 (PGE2) (median 10.1-fold rise, p=0.002) and reduced tumour necrosis factor-α (median 28% reduction, p=0.025). Blocking MSC PGE2 production by cyclo-oxygenase-2 (COX-2) inhibition with celecoxib abrogated the antimicrobial effect, while this was restored by adding exogenous PGE2. MSC-treated mice had lower pulmonary CFUs (median 18% reduction, p=0.012), but no significant change in spleen or liver CFUs compared with controls.
CONCLUSIONS: MSCs can modulate inflammation and reduce intracellular M. avium growth in human macrophages via COX-2/PGE2 signalling and inhibit pulmonary bacterial replication in a murine model of chronic MAC-PD.
摘要：
背景：对于鸟分枝杆菌复杂性肺病（MAC-PD），迫切需要新的治疗策略。人骨髓间充质基质细胞(MSCs)可直接抑制MAC生长,但是它们对胞内杆菌的影响是未知的。我们研究了人MSC减少MAC感染的巨噬细胞和MAC-PD的鼠模型中细菌复制和炎症的能力。
方法:用鸟分枝杆菌切斯特菌株感染人单核细胞衍生的巨噬细胞(MDMs)并用人骨髓衍生的MSC处理。在72小时时计数细胞内和细胞外集落形成单位(CFU)。6周龄的雌性balb/c小鼠通过M.aviumChester的雾化感染。在感染后21天和28天用1×106静脉内人类MSC或盐水对照处理小鼠。肺,感染后42天收集肝脏和脾脏进行细菌计数。通过ELISA定量细胞因子。
结果：MSCs在72小时内减少了MDM中的细胞内细菌（中位数减少了35％，p=0.027)。MSC治疗增加了前列腺素E2（PGE2）的细胞外浓度（中位数增加10.1倍，p=0.002)和降低的肿瘤坏死因子-α(中位数降低28%，p=0.025)。用塞来昔布抑制环加氧酶-2（COX-2）抑制MSCPGE2的产生消除了抗菌作用，而这是通过添加外源PGE2恢复的。MSC治疗的小鼠具有较低的肺CFU（中位数减少18%，p=0.012),但与对照组相比，脾脏或肝脏CFU无明显变化。
结论：MSC可以通过COX-2/PGE2信号调节炎症并减少人巨噬细胞的细胞内鸟分枝杆菌生长，并在慢性MAC-PD的鼠模型中抑制肺细菌复制。
方法:用鸟分枝杆菌切斯特菌株感染人单核细胞衍生的巨噬细胞(MDMs)并用人骨髓衍生的MSC处理。在72小时时计数细胞内和细胞外集落形成单位(CFU)。6周龄的雌性balb/c小鼠通过M.aviumChester的雾化感染。在感染后21天和28天用1×106静脉内人类MSC或盐水对照处理小鼠。肺,感染后42天收集肝脏和脾脏进行细菌计数。通过ELISA定量细胞因子。
结果：MSCs在72小时内减少了MDM中的细胞内细菌（中位数减少了35％，p=0.027)。MSC治疗增加了前列腺素E2（PGE2）的细胞外浓度（中位数增加10.1倍，p=0.002)和降低的肿瘤坏死因子-α(中位数降低28%，p=0.025)。用塞来昔布抑制环加氧酶-2（COX-2）抑制MSCPGE2的产生消除了抗菌作用，而这是通过添加外源PGE2恢复的。MSC治疗的小鼠具有较低的肺CFU（中位数减少18%，p=0.012),但与对照组相比，脾脏或肝脏CFU无明显变化。
结论：MSC可以通过COX-2/PGE2信号调节炎症并减少人巨噬细胞的细胞内鸟分枝杆菌生长，并在慢性MAC-PD的鼠模型中抑制肺细菌复制。
