Epitope mapping by a Wnt-blocking antibody: evidence of the Wnt binding domain in heparan sulfate.
Epitope mapping by a Wnt-blocking antibody: evidence of the Wnt binding domain in heparan sulfate.
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DOI：
10.1038/srep26245
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发表时间：
2016-05-17
影响因子：
4.6
通讯作者：
Ho M
中科院分区：
文献类型：
--
作者：
Gao W;Xu Y;Liu J;Ho M
硫酸乙酰肝素（HS）是已知调节许多重要生物过程（包括Wnt信号传导）的多糖。然而，HS和Wnt分子之间的生物化学相互作用并没有得到很好的表征，主要是由于缺乏合适的方法。为了确定HS中的Wnt结合结构域，我们使用了Wnt信号传导抑制抗体（HS 20）和一组具有不同长度和硫酸化修饰的合成HS寡糖。我们发现，HS 20与硫酸乙酰肝素的结合需要在C2位置（2-O-硫酸化）和C6位置（6-O-硫酸化）的硫酸化。对HS 20结合具有最大竞争效应的寡糖的长度在6至8个糖残基之间。此外，如果存在额外的3-O-硫酸化修饰，则HS 20也可以识别四个残基长的寡糖。此外，具有2-O、6-O和3-O-硫酸化的类似寡糖显示对Wnt活化的抑制。这些结果表明，HS 20和Wnt识别含有IdoA 2S和GlcNS 6S的HS结构，并且GlcNS 6S 3S中的3-O-硫酸化显著增强HS 20和Wnt两者的结合。本研究为鉴定HS中的Wnt结合结构域提供了证据，并为靶向Wnt和HS在癌症和其他疾病中的相互作用提供了治疗方法。
Heparan sulfate (HS) is a polysaccharide known to modulate many important biological processes, including Wnt signaling. However, the biochemical interaction between HS and Wnt molecules is not well characterized largely due to the lack of suitable methods. To determine the Wnt binding domain in HS, we used a Wnt signaling-inhibitory antibody (HS20) and a panel of synthetic HS oligosaccharides with distinct lengths and sulfation modifications. We found that the binding of HS20 to heparan sulfate required sulfation at both the C2 position (2-O-sulfation) and C6 position (6-O-sulfation). The oligosaccharides with the greatest competitive effect for HS20 binding were between six and eight saccharide residues in length. Additionally, a four residue-long oligosaccharide could also be recognized by HS20 if an additional 3-O-sulfation modification was present. Furthermore, similar oligosaccharides with 2-O, 6-O and 3-O-sulfations showed inhibition for Wnt activation. These results have revealed that HS20 and Wnt recognize a HS structure containing IdoA2S and GlcNS6S, and that the 3-O-sulfation in GlcNS6S3S significantly enhances the binding of both HS20 and Wnt. This study provides the evidence for identifying the Wnt binding domain in HS and suggests a therapeutic approach to target the interaction of Wnt and HS in cancer and other diseases.