GLCE regulates PC12 cell neuritogenesis induced by nerve growth factor through activating SMAD/ID3 signalling.
GLCE regulates PC12 cell neuritogenesis induced by nerve growth factor through activating SMAD/ID3 signalling.
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DOI：
10.1042/bj20131360
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发表时间：
2014-04
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影响因子：
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通讯作者：
Jie Li;Jianping Fang;Yi Qin;Wenfeng Liao;Hailing Liu;Yifa Zhou;K. Ding
中科院分区：
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作者：
Jie Li;Jianping Fang;Yi Qin;Wenfeng Liao;Hailing Liu;Yifa Zhou;K. Ding
神经发育是由一系列生长因子-硫酸乙酰肝素(HS)相互作用来协调的，这些相互作用参与了神经发生。葡萄糖醛酸差向异构酶(GLCE)是HS合成过程中的一个关键酶，它将D-葡萄糖醛酸(GLCA)转化为DIOA(L-艾杜糖酸)。然而，GLCE在神经发生中的作用在很大程度上是未知的。在本研究中，我们发现GLCE耗竭导致PC12细胞生长受阻，并促进神经生长因子(NGF)诱导的细胞神经发生和分化。GLCE的过度表达促进了PC12细胞的生长，挽救GLCE耗竭的PC12细胞的神经发生受到损害。有趣的是，Y168A和Y222A突变的野生型GLCE过表达导致PC12细胞生长增强，并减弱了GLCE沉默引发的神经再生。我们进一步证明，GLCE的缺失阻断了Smad1/5/8的磷酸化；然而，这一信号可以通过GLCE或其活性酶位点的突变来恢复。此外，GLCE还可诱导Smad1/5/8、ID3(DNA结合/分化抑制因子3)的下游效应。ID3沉默抑制PC12细胞生长，诱导细胞神经发生和分化。此外，ID3的异位表达部分挽救了GLCE沉默所导致的表型。本研究结果提示，GLCE通过SMAD/ID3信号通路在PC12细胞生长和神经发生中起关键作用。
Neurodevelopment is orchestrated by a series of growth factor-HS (heparan sulfate) interactions which are involved in neuritogenesis. GLCE (glucuronic acid epimerase) is a critical enzyme involved in HS synthesis, which converts GlcA (D-glucuronic acid) into IdoA (L-iduronic acid). However, the function of GLCE in neuritogenesis is largely unknown. In the present study we showed that GLCE depletion caused arrested PC12 cell growth and promoted the cell neuritogenesis and differentiation induced by NGF (nerve growth factor). PC12 cell growth was boosted by overexpression of GLCE, and neuritogenesis was impaired when GLCE depletion was rescued. Interestingly, overexpression of wild-type GLCE with Y168A and Y222A mutations led to enhanced PC12 cell growth and attenuated the neuritogenesis triggered by GLCE silencing. We showed further that GLCE depletion blocked SMAD1/5/8 phosphorylation; however, this signalling could be restored by GLCE or the mutation of its active enzymatic site. In addition, the downstream effector of SMAD1/5/8, ID3 (inhibitor of DNA binding/differentiation 3) was induced by GLCE. ID3 silencing inhibited PC12 cell growth and induced cell neuritogenesis and differentiation. In addition, ectopic expression of ID3 partially rescued the phenotype caused by GLCE silencing. The results of the present study suggest that GLCE plays a key role in PC12 cell growth and neuritogenesis through SMAD/ID3 signalling.