Laboratory for Reproductive Immunology, Hospital and Institute of Obstetrics and Gynecology, Fudan University Shanghai Medical College, 413 Zhaozhou Road, Shanghai 200011, China.
Placenta. 2012 May;33(5):387-91. doi: 10.1016/j.placenta.2012.01.015. Epub 2012 Feb 10.
Our previous study has demonstrated that thymic stromal lymphopoietin (TSLP) stimulates trophoblast proliferation and invasion, suggesting TSLP plays an important role in the placentation in early human pregnancy, but the intracellular molecular mechanism is currently unknown. The present study is undertaken to investigate whether the STAT3-c-Myc signaling pathway is involved in TSLP-mediated trophoblast proliferation. Primary human first-trimester trophoblasts were treated with TSLP only, or TSLP combined with different signaling inhibitors (STAT3, STAT5, AKT, and ERK). The levels of STAT3 tyrosine phosphorylation and c-Myc expression were determined by using Western blot analysis, and the proliferation of trophoblasts was analyzed by BrdU cell proliferation assay. JEG-3 cells were transfected with siRNA targeting to c-Myc, and the proliferation was determined in JEG-3 cells treated with TSLP only, or TSLP combined with c-Myc silencing. It was revealed that treatment with TSLP significantly enhanced STAT3 phosphorylation and c-Myc expression in human trophoblasts. The effect of TSLP upregulation on trophoblast proliferation was abrogated completely by either STAT3 inhibitor or c-Myc siRNA silence. We further found that the upregulation of TSLP on c-Myc expression was abrogated completely by the STAT3 inhibitor, which suggests that the intracellular STAT3 phosphorylation is an upstream signal of c-Myc expression in the TSLP-stimulated trophoblast proliferation. These results suggest that TSLP may upregulate c-Myc expression through activation of STAT3 pathway, thereby inducing trophoblast proliferation.
我们之前的研究表明胸腺基质淋巴细胞生成素（TSLP）刺激滋养细胞增殖和侵袭，提示 TSLP 在人类早期妊娠胎盘形成中发挥重要作用，但目前尚不清楚其细胞内分子机制。本研究旨在探讨 STAT3-c-Myc 信号通路是否参与 TSLP 介导的滋养细胞增殖。用 TSLP 单独或 TSLP 联合不同信号抑制剂（STAT3、STAT5、AKT 和 ERK）处理原代人早孕滋养细胞。采用 Western blot 分析检测 STAT3 酪氨酸磷酸化和 c-Myc 表达水平，BrdU 细胞增殖试验分析滋养细胞增殖。用靶向 c-Myc 的 siRNA 转染 JEG-3 细胞，并用 TSLP 单独或 TSLP 联合 c-Myc 沉默处理 JEG-3 细胞，测定增殖情况。结果显示，TSLP 处理显著增强了人滋养细胞中 STAT3 磷酸化和 c-Myc 表达。STAT3 抑制剂或 c-Myc siRNA 沉默完全阻断了 TSLP 上调对滋养细胞增殖的影响。我们进一步发现，STAT3 抑制剂完全阻断了 TSLP 对 c-Myc 表达的上调，提示 STAT3 磷酸化是 TSLP 刺激滋养细胞增殖中 c-Myc 表达的上游信号。这些结果表明，TSLP 可能通过激活 STAT3 通路上调 c-Myc 表达，从而诱导滋养细胞增殖。
