• Molecules and Cells
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• 제43권5호
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• pp.479-490
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• 2020

Interleukin-9 (IL-9) is well known for its role in allergic inflammation. For cancer, both pro- and anti-tumor effects of IL-9 were controversially reported, but the impact of IL-9 on tumor metastasis has not yet been clarified. In this study, IL-9 was expressed as a secretory form (sIL-9) and a membrane-bound form (mbIL-9) on B16F10 melanoma cells. The mbIL-9 was engineered as a chimeric protein with the transmembrane and cytoplasmic region of TNF-α. The effect of either mbIL-9 or sIL-9 expressing cells were analyzed on the metastasis capability of the cancer cells. After three weeks of tumor implantation into C57BL/6 mice through the tail vein, the number of tumor modules in lungs injected with IL-9 expressing B16F10 was 5-fold less than that of control groups. The percentages of CD4⁺ T cells, CD8⁺ T cells, NK cells, and M1 macrophages considerably increased in the lungs of the mice injected with IL-9 expressing cells. Among them, the M1 macrophage subset was the most significantly enhanced. Furthermore, peritoneal macrophages, which were stimulated with either sIL-9 or mbIL-9 expressing transfectant, exerted higher anti-tumor cytotoxicity compared with that of the mock control. The IL-9-stimulated peritoneal macrophages were highly polarized to M1 phenotype. Stimulation of RAW264.7 macrophages with sIL-9 or mbIL-9 expressing cells also significantly increased the cytotoxicity of those macrophages against wild-type B16F10 cells. These results clearly demonstrate that IL-9 can induce an anti-metastasis effect by enhancing the polarization and proliferation of M1 macrophages.

• IMMUNE NETWORK
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• 제22권5호
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• pp.40.1-40.24
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• 2022

Mesenchymal stem cells (MSCs) are attractive alternatives to conventional anti-asthmatic drugs for severe asthma. Mechanisms underlying the anti-asthmatic effects of MSCs have not yet been elucidated. This study evaluated the anti-asthmatic effects of intravenously administered MSCs, focusing on macrophages and monocytes. Seven-week-old transgenic (Tg) mice with lung-specific overexpression of IL-13 were used to simulate chronic asthma. MSCs were intravenously administered four days before sampling. We examined changes in immune cell subpopulations, gene expression, and histological phenotypes. IL-13 Tg mice exhibited diverse features of chronic asthma, including severe type 2 inflammation, airway fibrosis, and mucus metaplasia. Intravenous administration of MSCs attenuated these asthmatic features just four days after a single treatment. MSC treatment significantly reduced SiglecF^-CD11c^-CD11b⁺ monocyte-derived macrophages (MoMs) and inhibited the polarization of MoMs into M2 macrophages, especially M2a and M2c. Furthermore, MSCs downregulated the excessive accumulation of Ly6c^- monocytes in the lungs. While an intravenous adoptive transfer of Ly6c^- monocytes promoted the infiltration of MoM and Th2 inflammation, that of MSC-exposed Ly6c^- monocytes did not. Ex vivo Ly6c^- MoMs upregulated M2-related genes, which were reduced by MSC treatment. Molecules secreted by Ly6c^- MoMs from IL-13 Tg mice lungs upregulated the expression of fibrosis-related genes in fibroblasts, which were also suppressed by MSC treatment. In conclusion, intravenously administered MSCs attenuate asthma phenotypes of chronic asthma by modulating macrophages. Identifying M2 macrophage subtypes revealed that exposure to MSCs transforms the phenotype and function of macrophages. We suggest that Ly6c^- monocytes could be a therapeutic target for asthma management.