Respiratory Syncytial Virus-Infected Mesenchymal Stem Cells Regulate Immunity via Interferon Beta and Indoleamine-2,3-Dioxygenase
Respiratory Syncytial Virus-Infected Mesenchymal Stem Cells Regulate Immunity via Interferon Beta and Indoleamine-2,3-Dioxygenase
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DOI：
10.1371/journal.pone.0163709
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发表时间：
2016-10-03
期刊：
影响因子：
3.7
通讯作者：
Mohapatra, Shyam S.
中科院分区：
文献类型：
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作者：
Cheung, Michael B.;Sampayo-Escobar, Viviana;Mohapatra, Shyam S.
呼吸道合胞病毒（RSV）已被报道感染人间充质干细胞（MSC），但其后果知之甚少。骨髓间充质干细胞存在于几乎所有器官，包括鼻粘膜和肺，并在调节免疫反应和介导组织修复中发挥作用。我们试图确定RSV感染MSC是否会增强其免疫调节功能，并导致RSV相关的肺部疾病。通过荧光显微镜、空斑测定和RSV转录物的表达显示RSV在人MSC中复制。与上皮细胞相比，RSV感染的MSC显示细胞因子和趋化因子如IL-1 β、IL-6、IL-8和SDF-1的表达差异改变。值得注意的是，与模拟感染的MSC相比，RSV感染的MSC表现出IFN-β（类似于100倍）和吲哚胺-2，3-双加氧酶（IDO）（类似于70倍）的表达显著增加。IDO通过蛋白质印迹鉴定在感染细胞的胞质蛋白中，并且通过色氨酸催化试验检测酶活性。用来自RSV感染的MSC的培养上清液处理PBMC以剂量依赖性方式降低其增殖。通过在RSV感染期间用IDO抑制剂1-甲基色氨酸和维生素K-3处理MSC来逆转这种对PBMC活化的影响，我们通过CRISPR/Cas9介导的MSC中IDO敲除证实了这一结果。中和IFN-β阻止IDO表达和活性。用内体TLR抑制剂以及TLR 3/dsRNA复合物的特异性抑制剂处理MSC阻止IFN-β和IDO表达。总之，这些结果表明，RSV感染MSC通过上调IFN-β和IDO改变其免疫调节功能，影响免疫细胞增殖，这可能是缺乏保护性RSV免疫和RSV相关肺部疾病如哮喘和COPD慢性化的原因。
Respiratory syncytial virus (RSV) has been reported to infect human mesenchymal stem cells (MSCs) but the consequences are poorly understood. MSCs are present in nearly every organ including the nasal mucosa and the lung and play a role in regulating immune responses and mediating tissue repair. We sought to determine whether RSV infection of MSCs enhances their immune regulatory functions and contributes to RSV-associated lung disease. RSV was shown to replicate in human MSCs by fluorescence microscopy, plaque assay, and expression of RSV transcripts. RSV-infected MSCs showed differentially altered expression of cytokines and chemokines such as IL-1 beta, IL6, IL-8 and SDF-1 compared to epithelial cells. Notably, RSV-infected MSCs exhibited significantly increased expression of IFN-beta (similar to 100-fold) and indoleamine-2,3-dioxygenase (IDO) (similar to 70-fold) than in mock-infected MSCs. IDO was identified in cytosolic protein of infected cells by Western blots and enzymatic activity was detected by tryptophan catabolism assay. Treatment of PBMCs with culture supernatants from RSV-infected MSCs reduced their proliferation in a dose dependent manner. This effect on PBMC activation was reversed by treatment of MSCs with the IDO inhibitors 1-methyltryptophan and vitamin K-3 during RSV infection, a result we confirmed by CRISPR/Cas9-mediated knockout of IDO in MSCs. Neutralizing IFN-beta prevented IDO expression and activity. Treatment of MSCs with an endosomal TLR inhibitor, as well as a specific inhibitor of the TLR3/dsRNA complex, prevented IFN-beta and IDO expression. Together, these results suggest that RSV infection of MSCs alters their immune regulatory function by upregulating IFN-beta and IDO, affecting immune cell proliferation, which may account for the lack of protective RSV immunity and for chronicity of RSV-associated lung diseases such as asthma and COPD.