Zheng Guoping, Qiu Guanguan, Ge Menghua, He Jianping, Huang Lanfang, Chen Ping, Wang Wei, Xu Qi, Hu Yaoqin, Shu Qiang, Xu Jianguo
Shaoxing Second Hospital, 123 Yanan Road, Shaoxing, Zhejiang, 312000, China.
The Children's Hospital of Zhejiang University School of Medicine, 3333 Binsheng Road, Hangzhou, Zhejiang, 310051, China.
Respir Res. 2017 Jun 15;18(1):119. doi: 10.1186/s12931-017-0599-5.
Long-term survival of lung transplantation is hindered by the development of obliterative bronchiolitis (OB). Adipose-derived stem cells (ASCs) were documented to have more potent immunosuppressive ability than mesenchymal stem cells (MSCs) from bone marrow and placenta. The goal of our study is to evaluate the effect of repeated administration of ASCs on OB and the involvement of indoleamine 2,3-dioxygenase (IDO) mediating the protective effect of ASCs in a heterotopic tracheal transplantation (HTT) model.
For studies in vitro, ASCs were treated with interferon-γ (IFN-γ). For in vivo study, tracheas from BALB/c or C57BL/6 donors were transplanted into C57BL/6 recipients to create a HTT model. On days 0, 1, 3, 5, 8, 12, 15, 20 and 25 post-transplant, the allogeneic recipient mice were administered intravenously with phosphate buffered saline, 1 × 10 human ASCs, or 1 × 10 human ASCs plus 1-methyltryptophan (1-MT), an IDO inhibitor. On days 3, 7, 14 and 28, serum, trachea and spleen samples were harvested for analysis.
ASCs homed to heterotopic tracheal grafts after infusion. Multiple doses of ASCs significantly increased tracheal IDO levels in allografts. There were significant increases in graft and serum IFN-γ levels in allografts compared with isografts. IFN-γ elevated IDO expression and activity in ASCs in vitro. ASCs alleviated OB in allografts as evidenced by reduced epithelial loss, epithelial apoptosis, and intraluminal obstruction. The effects of ASCs on OB were blocked by 1-MT. 1-MT also blocked the alterations in pro and anti-inflammatory cytokines as well as CD3+ T cell infiltration induced by ASCs. ASCs induced not only splenic levels of CD4+CD25+Foxp3+ regulatory T cells (Treg) but also IL-10 and TGF-β-producing Treg. Furthermore, IDO inhibition abolished the changes of splenic Treg induced by ASCs. In addition, Treg reduction by cyclophosphamide treatment did not alter the effects of ASCs on tracheal IDO expression in allografts confirming Treg induction is downstream of IDO.
Repeated doses of ASCs are capable of ameliorating OB. ASCs act at least in part via elevating IDO expression. ASCs promote the generation of Treg and suppress T cell infiltration via an IDO-dependent mechanism.
闭塞性细支气管炎（OB）的发展阻碍了肺移植的长期存活。有文献记载，脂肪来源的干细胞（ASC）比骨髓和胎盘来源的间充质干细胞（MSC）具有更强的免疫抑制能力。我们研究的目的是评估重复给予ASC对OB的影响，以及吲哚胺2,3-双加氧酶（IDO）介导ASC在异位气管移植（HTT）模型中的保护作用。
在体外研究中，用干扰素-γ（IFN-γ）处理ASC。在体内研究中，将来自BALB/c或C57BL/6供体的气管移植到C57BL/6受体中以建立HTT模型。在移植后的第0、1、3、5、8、12、15、20和25天，给同种异体受体小鼠静脉注射磷酸盐缓冲盐水、1×10个人ASC或1×10个人ASC加IDO抑制剂1-甲基色氨酸（1-MT）。在第3、7、14和28天，采集血清、气管和脾脏样本进行分析。
输注后ASC归巢到异位气管移植物中。多次给予ASC显著提高了同种异体移植物中气管IDO水平。与同基因移植物相比，同种异体移植物中移植物和血清IFN-γ水平显著升高。IFN-γ在体外提高了ASC中IDO的表达和活性。ASC减轻了同种异体移植物中的OB，表现为上皮损失、上皮凋亡和管腔内阻塞减少。1-MT阻断了ASC对OB的影响。1-MT还阻断了ASC诱导的促炎和抗炎细胞因子以及CD3+T细胞浸润的改变。ASC不仅诱导了脾脏中CD4+CD25+Foxp3+调节性T细胞（Treg）水平，还诱导了产生IL-10和TGF-β的Treg。此外，IDO抑制消除了ASC诱导的脾脏Treg的变化。此外，用环磷酰胺处理减少Treg并没有改变ASC对同种异体移植物中气管IDO表达的影响，证实Treg诱导是在IDO下游。
重复给予ASC能够改善OB。ASC至少部分通过提高IDO表达起作用。ASC通过IDO依赖性机制促进Treg的产生并抑制T细胞浸润。
