Toxoplasma gondii inhibits differentiation of C17.2 neural stem cells through Wnt/β-catenin signaling pathway
Toxoplasma gondii inhibits differentiation of C17.2 neural stem cells through Wnt/β-catenin signaling pathway
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弓形虫通过Wnt/β-catenin信号通路抑制C17.2神经干细胞分化
DOI：
10.1016/j.bbrc.2016.03.076
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发表时间：
2016-04-22
影响因子：
3.1
通讯作者：
Yu, Li
中科院分区：
文献类型：
--
作者：
Gan, Xiaofeng;Zhang, Xian;Yu, Li
刚地弓形虫是导致先天性脑部疾病的主要原因。发育中的胎儿感染弓形虫经常导致严重的神经发育损伤；然而，寄生虫感染对胎儿大脑发育的关键角色神经干细胞的影响仍然难以捉摸。本研究旨在探讨弓形虫感染对神经干细胞（NSCs）分化的影响，阐明弓形虫感染诱导NSCs分化抑制的分子机制。分化标志物β iii -微管蛋白和胶质纤维酸性蛋白（GFAP）的免疫荧光染色表明，C17.2神经干细胞（NSCs）在DMEM:F12（1:1混合物）中分别分化为神经元和星形胶质细胞。在分化培养基中培养5天后，弓形虫分泌抗原（tg - esa）显著下调C17.2 NSCs中diii -微管蛋白和GFAP蛋白水平，且呈剂量依赖性。wnt3a （Wnt/ β -catenin信号通路的关键激活因子）和tg - esa处理的C17.2细胞细胞核中β -catenin蛋白水平显著低于单独处理的细胞，但显著高于单独处理的细胞。综上所述，弓形虫RH的ESAs阻断了C17.2 ncs的分化，下调了Wnt/ β -catenin信号通路的重要组成部分β -catenin的表达。这些发现提示弓形虫感染诱导神经发病的新机制，即通过阻断Wnt/ β -catenin信号通路抑制NSCs的分化，如寄生虫esa下调β -catenin的表达。(C) 2016 Elsevier Inc.版权所有。
Toxoplasma gondii is a major cause of congenital brain disease. T gondii infection in the developing fetus frequently results in major neural developmental damage; however, the effects of the parasite infection on the neural stem cells, the key players in fetal brain development, still remain elusive. This study is aiming to explore the role of T. gondii infection on differentiation of neural stem cells (NSCs) and elucidate the underlying molecular mechanisms that regulate the inhibited differentiation of NSCs induced by the infection. Using a differentiation medium, i.e., DMEM:F12 (1:1 mixture) supplemented with 2% N2, C17.2 neural stem cells (NSCs) were able to differentiate to neurons and astrocytes, respectively evidenced by immunofluorescence staining of differentiation markers including beta III-tubulin and glial fibrillary acidic protein (GFAP). After 5 -day culture in the differentiation medium, the excreted secreted antigens of T gondii (Tg-ESAs) significantly down -regulated the protein levels of DIII-tubulin and GFAP in C17.2 NSCs in a dose -dependent manner. The protein level of beta-catenin in the nucleus of C17.2 cells treated with both wnt3a (a key activator for Wnt/beta-catenin signaling pathway) and Tg-ESAs was significantly lower than that in the cells treated with only wnt3a, but significantly higher than that in the cells treated with only Tg-ESAs. In conclusion, the ESAs of T. gondii RH blocked the differentiation of C17.2 NCSs and downregulated the expression of beta-catenin, an essential component of Wnt/beta-catenin signaling pathway. The findings suggest a new mechanism underlying the neuropathogenesis induced by T gondii infection, i.e. inhibition of the differentiation of NSCs via blockade of Wnt/beta-catenin signaling pathway, such as downregulation of beta-catenin expression by the parasite ESAs. (C) 2016 Elsevier Inc. All rights reserved.