Inflammatory Bowel Disease Center, Humanitas Clinical and Research Center, Milan, Italy.
Department of Immunology, Humanitas Clinical and Research Center, Milan, Italy.
Gastroenterology. 2015 Jul;149(1):163-176.e20. doi: 10.1053/j.gastro.2015.03.013. Epub 2015 Mar 17.
BACKGROUND & AIMS: Mesenchymal stem cells (MSCs) are pluripotent cells that can promote expansion of immune regulatory cells and might be developed for the treatment of immune disorders, including inflammatory bowel diseases. MSCs were reported to reduce colitis in mice; we investigated whether MSC localization to the intestine and production of paracrine factors, including tumor necrosis factor-induced protein 6 (TSG6), were required for these effects.
MSCs were isolated from bone marrow (BM-MSCs) of 4- to 6-week-old C57BL/6, C57BL/6-green fluorescent protein, or Balb/c Tsg6-/- male mice. Colitis was induced by ad libitum administration of dextran sulfate sodium for 10 days; after 5 days the mice were given intraperitoneal injections of BM-MSCs or saline (controls). Blood samples and intestinal tissues were collected 24, 48, 96, and 120 hours later; histologic and flow cytometry analyses were performed.
Injection of BM-MSCs reduced colitis in mice, increasing body weight and reducing markers of intestinal inflammation, compared with control mice. However, fewer than 1% of MSCs reached the inflamed colon. Most of the BM-MSCs formed aggregates in the peritoneal cavity. The aggregates contained macrophages and B and T cells, and produced immune-regulatory molecules including FOXP3, interleukin (IL)10, transforming growth factor-β, arginase type II, chemokine (C-C motif) ligand 22 (CCL22), heme oxygenase-1, and TSG6. Serum from mice given BM-MSCs, compared with mice given saline, had increased levels of TSG6. Injection of TSG6 reduced the severity of colitis in mice, along with the numbers of CD45+ cells, neutrophils and metalloproteinase activity in the mucosa, while increasing the percentage of Foxp3CD45+ cells. TSG6 injection also promoted the expansion of regulatory macrophages that expressed IL10 and inducible nitric oxide synthase, and reduced serum levels of interferon-γ, IL6, and tumor necrosis factor. Tsg6-/- MSCs did not suppress the mucosal inflammatory response in mice with colitis.
BM-MSCs injected into mice with colitis do not localize to the intestine but instead form aggregates in the peritoneum where they produce immunoregulatory molecules, including TSG6, that reduce intestinal inflammation. TSG6 is sufficient to reduce intestinal inflammation in mice with colitis.
间充质干细胞（MSCs）是一种多能细胞，可促进免疫调节细胞的扩增，并可能被开发用于治疗免疫紊乱，包括炎症性肠病。有报道称 MSCs 可减轻小鼠结肠炎；我们研究了 MSC 向肠道的定位和旁分泌因子（包括肿瘤坏死因子诱导蛋白 6（TSG6））的产生是否是这些作用所必需的。
从 4-6 周龄 C57BL/6、C57BL/6-绿色荧光蛋白或 Balb/c Tsg6-/-雄性小鼠的骨髓（BM-MSCs）中分离 MSC。通过自由给予葡聚糖硫酸钠诱导结肠炎 10 天；在第 5 天，给小鼠腹腔内注射 BM-MSCs 或生理盐水（对照）。在 24、48、96 和 120 小时后采集血样和肠组织；进行组织学和流式细胞术分析。
与对照小鼠相比，注射 BM-MSCs 可减轻小鼠结肠炎，增加体重并减少肠道炎症标志物。然而，不到 1%的 MSC 到达发炎的结肠。大多数 BM-MSCs 在腹腔内形成聚集体。聚集体中含有巨噬细胞和 B 细胞和 T 细胞，并产生免疫调节分子，包括 FOXP3、白细胞介素（IL）10、转化生长因子-β、精氨酸酶 II、趋化因子（C-C 基序）配体 22（CCL22）、血红素加氧酶-1 和 TSG6。与给予生理盐水的小鼠相比，给予 BM-MSCs 的小鼠血清中 TSG6 水平升高。注射 TSG6 可减轻结肠炎小鼠的严重程度，减少黏膜中 CD45+细胞、中性粒细胞和金属蛋白酶活性，同时增加 Foxp3CD45+细胞的百分比。TSG6 注射还促进了表达 IL10 和诱导型一氧化氮合酶的调节性巨噬细胞的扩张，并降低了血清中干扰素-γ、IL6 和肿瘤坏死因子的水平。Tsg6-/-MSC 不能抑制结肠炎小鼠的黏膜炎症反应。
注射到患有结肠炎的小鼠体内的 BM-MSCs 不会定位于肠道，而是在腹膜中形成聚集体，在那里产生包括 TSG6 在内的免疫调节分子，可减轻肠道炎症。TSG6 足以减轻患有结肠炎的小鼠的肠道炎症。
