Karaöz Erdal, Çetinalp Demircan Pınar, Erman Gülay, Güngörürler Eda, Eker Sarıboyacı Ayla
Liv Hospital, Center for Regenerative Medicine and Stem Cell Research and Manufacturing, İstanbul, Turkey.
Turk J Haematol. 2017 Aug 2;34(3):213-225. doi: 10.4274/tjh.2016.0171. Epub 2016 Sep 9.
Mesenchymal stem cells (MSCs), which possess immunosuppressive characteristics on induced T-cells, were shown to be applicable in prevention and treatment of graft-versus-host disease. However, knowledge of effective cell sources is still limited. In this study, MSCs from different human tissues, i.e. bone marrow (BM), Wharton's jelly (WJ), and adipose tissue, were isolated, and the immune suppression of stimulated T cells was analyzed comparatively.
MSCs were co-cultured with phytohemagglutinin-induced T-cells with co-culture techniques with and without cell-to-cell contact. After co-culture for 24 and 96 h, the proliferation rate of T cells was estimated by carboxyfluorescein succinimidyl ester and apoptosis by annexin V/PI methods. Both T cells and MSCs were analyzed with respect to gene expressions by real-time polymerase chain reaction and their specific protein levels by ELISA.
The results showed that all three MSC lines significantly suppressed T-cell proliferation; BM-MSCs were most effective. Similarly, T-cell apoptosis was induced most strongly by BM-MSCs in indirect culture. In T cells, the genes in NFkB and tumor necrosis factor pathways were silenced and the caspase pathway was induced after co-culture. These results were confirmed with the measurement of protein levels, like transforming growth factor β1, IL-6, interferon-γ, interleukin (IL)-2, and tumor necrosis factor-α. Additionally, IL-17A was detected in high levels in WJ-MSC co-cultures. We showed that IL-17A-producing Tregs are the key mediators in the treatment of graft-versus-host disease.
BM-MSCs, which have been used in clinical applications for a while, showed the greatest immunosuppressive effect compared to other MSCs. However, a promising cell source could also be WJ, which is also effective in suppression with fewer ethical concerns. We described the molecular mechanism of WJ-MSCs in allogenic transplants for the first time.
间充质干细胞（MSCs）对诱导型T细胞具有免疫抑制特性，已证明其可用于预防和治疗移植物抗宿主病。然而，关于有效细胞来源的知识仍然有限。在本研究中，分离了来自不同人体组织即骨髓（BM）、华通氏胶（WJ）和脂肪组织的MSCs，并比较分析了其对活化T细胞的免疫抑制作用。
采用细胞间接触和非接触共培养技术，将MSCs与植物血凝素诱导的T细胞共培养。共培养24小时和96小时后，通过羧基荧光素琥珀酰亚胺酯法评估T细胞的增殖率，通过膜联蛋白V/PI法评估细胞凋亡情况。通过实时聚合酶链反应分析T细胞和MSCs的基因表达，并通过酶联免疫吸附测定法分析其特定蛋白水平。
结果显示，所有三种MSCs系均能显著抑制T细胞增殖；骨髓间充质干细胞最有效。同样，在间接培养中，骨髓间充质干细胞对T细胞凋亡的诱导作用最强。在T细胞中，共培养后NFkB和肿瘤坏死因子途径中的基因被沉默，半胱天冬酶途径被诱导。这些结果通过对转化生长因子β1、IL-6、干扰素-γ、白细胞介素（IL）-2和肿瘤坏死因子-α等蛋白质水平的测定得到证实。此外，在WJ-MSC共培养物中检测到高水平的IL-17A。我们表明，产生IL-17A的调节性T细胞是治疗移植物抗宿主病的关键介质。
已在临床应用一段时间的骨髓间充质干细胞与其他MSCs相比显示出最大的免疫抑制作用。然而，有前景的细胞来源也可能是WJ，其在免疫抑制方面同样有效且伦理问题较少。我们首次描述了WJ-MSCs在同种异体移植中的分子机制。
