摘要
目的 探讨胸腺肽α1（Tα1）调节再生障碍性贫血（AA）患儿骨髓间充质干细胞（MSCs）Toll样受体9（TLR9）及吲哚胺2,3-二氧化酶（IDO）信号通路介导的免疫抑制作用.方法 （1）流式细胞术检测正常儿童及AA患儿骨髓T细胞亚群;（2）逆转录-聚合酶链反应（RT-PCR）检测Tα1对AA患儿骨髓MSCs TLR9/IDO mRNA表达的影响;（3）MTT法及流式细胞术测定Tα1作用后AA患儿骨髓MSCs对PHA刺激T细胞增殖和活化的抑制作用.结果 （1）AA患儿骨髓T细胞CD4＋/CD8＋的比值（0.64±0.02）低于正常儿童（1.42±0.05）;而CD8＋/CD38＋的比值（0.92±0.04）高于正常儿童（0.65±0.05）;（2）AA患儿骨髓MSCs表达TLR9 mRNA,不表达IDO mRNA;Tα1与AA患儿骨髓MSCs作用18 h后,明显下调TLR9表达和上调IDO表达,且呈浓度和时间依赖关系;（3）AA患儿骨髓MSCs对T细胞增殖的抑制率（21.38±12.34）%显著低于正常儿童（62.72±17.79）%（P＜0.05）;Tα1作用18 h后,AA患儿骨髓MSCs对T细胞的抑制率明显增加（42.83±16.54）%（P＜0.05）.结论 AA患儿骨髓MSCs的免疫抑制作用存在缺陷,Tα1经TLR9信号通路诱导AA患儿骨髓MSCs表达IDO,改善MSCs对T细胞的抑制作用.
Objective To study the regulatory effect of thymosin α1 （Tα1） on immunosuppression of bone marrow mesenchymal stem cells （MSCs） from children with aplastic anemia （AA） through Toll-like receptor 9（TLR9）and indoleamine 2,3-dioxygenase（ IDO）signaling pathway. Method Bone marrow T cell subsets from children with AA and normal individuals were measured by using flow cytometry. Expressions of TLR9/IDO mRNA of MSCs cocultured with Tα1 were determined by reverse-transcription PCR （RT-PCR）.Inhibition of PHA-activated T cell proliferation and activation by MSCs cocultured with Tα1 was detected by using MTT assay and flow cytometry. Result CD4 ＋/CD8 ＋ ratio （0. 64 ± 0. 02 ） in children with AA was significantly lower than that in normal individuals （ 1.42 ± 0. 05 ）; but CD8 ＋/CD38 ＋ ratio （0. 92 ± 0. 04）was significantly higher than that in normal individuals （0. 65 ± 0. 05 ）. AA MSCs obviously expressed TLR9, but not IDO; AA MSCs treated with Tα1 downregulated TLR9 expression but upregulated IDO expression in concentration- and time-dependent manners. The inhibition of AA MSCs on T cell proliferation （21.38% ± 12. 34% ） was lower than that in normal individuals （62. 72% ± 17.79%, P ＜0. 05 ）, while AA MSCs treated with Tα1 for 18 h exhibited a stronger inhibition （42.83% ± 16.54%, P ＜ 0.05 ）.Conclusion The immunosuppression mediated by MSCs could be improved by Tα1 through upregulation of IDO expression via TLR9-dependent signaling pathway. This research provides a new idea for targeted immunomodulatory therapy with bone marrow MSCs from children with AA.
出处
《中华儿科杂志》
CAS
CSCD
北大核心
2011年第3期181-185,共5页
Chinese Journal of Pediatrics
基金
四川省卫生厅科研基金资助项目（080344）
