HMGA2 Modulates the TGFβ/Smad, TGFβ/ERK and Notch Signaling Pathways in Human Lens Epithelial-Mesenchymal Transition
HMGA2 Modulates the TGFβ/Smad, TGFβ/ERK and Notch Signaling Pathways in Human Lens Epithelial-Mesenchymal Transition
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HMGA2 调节人类晶状体上皮-间质转化中的 TGFβ/Smad、TGFβ/ERK 和 Notch 信号通路
DOI：
10.2174/1566524018666180705104844
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发表时间：
2018-01-01
影响因子：
2.5
通讯作者：
Wu, M.
中科院分区：
文献类型：
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作者：
Hou, M.;Bao, X.;Wu, M.
背景与目的：多种信号通路协同促进晶状体上皮细胞(LECs)上皮-间充质转化(EMT)，其中转化生长因子-β(TGF-β)介导的信号转导起着核心作用。但这些通路之间的串扰机制仍然不清楚。本研究旨在探讨高迁移率族蛋白A2(HMGA2)对晶状体纤维化信号转导通路的调节作用。培养人SRA01/04 LEC，加入重组人转化生长因子β2(5 ng/ml)。为抑制信号通路，分别向LECs中加入选择性抑制剂SB431542、U0126或DAPT。将特异性小干扰RNA(SiRNA)导入晶状体上皮细胞，实现基因沉默。结果：HMGA2和EMT标志物α-平滑肌肌动蛋白(SMA)、纤维连接蛋白(FN)和I型胶原(Col-I)在人ASC组织中高表达，转化生长因子β2(TGF-β2)刺激LECs转化。用选择性的转化生长因子β/Smad抑制剂、转化生长因子β/细胞外信号调节激酶(ERK)或Notch信号通路阻断EMT可显著抑制HMGA2蛋白的表达。SiRNA沉默HMGA2可显著抑制转化生长因子β2诱导的EMT标志物FN、Col I、Col IV、关键转录因子Snail和Slug的表达，显著上调上皮标志物E-钙粘素和紧密连接蛋白(ZO-1)的表达。此外，沉默HMGA2基因还可以阻断转化生长因子β2诱导的Smad2、Smad3和ERK1/2的磷酸化。阻断HMGA2还可以抑制转化生长因子β2诱导的Jagged1、Notch2和Notch3的上调。结论：HMGA2在转化生长因子β2诱导的晶状体纤维化中起共同的效应作用，在正反馈环中调节EMT所需的信号网络。
Background and Objective: Multiple signaling pathways coordinately promote epithelial-mesenchymal transition (EMT) in lens epithelial cells (LECs), where transforming growth factor beta (TGF beta)-mediated signaling plays a central role. But the mechanism of crosstalk among these pathways remains obscure. The objective of this study is to investigate the regulatory effect of the high mobility group protein A2 (HMGA2) on the signaling pathways in lens fibrosis.Methods: The human anterior capsulorhexis specimens were collected. The human SRA01/04 LEC line was cultured and treated with recombinant human TGF beta 2 (5ng/ml). For inhibition of signaling pathways, a selective inhibitor SB431542, U0126 or DAPT was added to LECs respectively. The specific small interfering RNA (siRNA) were transfected to LECs for gene silence. The mRNAs expressions were measured by realtime PCR and the proteins expressions were determined by western blot and immunofluorescent staining.Results: HMGA2 and EMT markers a-smooth muscle actin (SMA), fibronectin (FN) and collagen type I (Col I) were overexpressed in human ASC specimens and TGF beta 2 stimulated EMT in LECs. While blockage of EMT by a selective inhibitor of TGF beta/Smad, TGF beta/extracellular signal-regulated kinase (ERK) or Notch signaling pathway could significantly inhibited HMGA2 protein expression. And silence of HMGA2 by siRNA could significantly inhibit TGF beta 2 induced expression of EMT markers including FN, Col I, collagen type IV (Col IV), key transcription factors Snail and Slug, and remarkably upregulate the epithelial markers E-cadherin and tight junction protein (ZO-1). In addition, silence of HMGA2 gene could abrogate TGF beta 2 induced phosphorylation of Smad2, Smad3 as well as ERK1/2. Blockage of HMGA2 could also inhibit the upregulation of Jaggedl, Notch2, and Notch3 induced by TGF beta 2.Conclusion: This study indicated that HMGA2 functions as a shared effector in TGF beta 2-induced lens fibrosis, modulating the signaling network necessary for EMT in a positive feedback loop.