Lacrimal Gland Development and Fgf10-Fgfr2b Signaling Are Controlled by 2-O- and 6-O-sulfated Heparan Sulfate
Lacrimal Gland Development and Fgf10-Fgfr2b Signaling Are Controlled by 2-O- and 6-O-sulfated Heparan Sulfate
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DOI：
10.1074/jbc.m111.225003
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发表时间：
2011-04-22
影响因子：
4.8
通讯作者：
Zhang, Xin
中科院分区：
文献类型：
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作者：
Qu, Xiuxia;Carbe, Christian;Zhang, Xin
硫酸乙酰肝素是一种广泛硫酸化的糖胺聚糖，在细胞表面蛋白聚糖上丰富，通过与各种生长因子和受体结合来调节细胞间信号传导。在泪腺中，分支形态发生取决于硫酸乙酰肝素与Fgf 10-Fgfr 2b的相互作用。为了解决泪腺发育和FGF信号传导是否依赖于糖醛酸的2-O-硫酸化和葡糖胺残基的6-O-硫酸化，我们在发育中的泪腺中基因消融硫酸乙酰肝素2-O和6-O磺基转移酶（Hs 2st、Hs 6st 1和Hs 6st 2）。使用一组噬菌体展示抗体，我们证实，这些突变破坏2-O和/或6-O，但不N-硫酸化的硫酸乙酰肝素。Hs 6st突变体表现出显著的泪腺发育不全和与Fgf 10的强遗传相互作用，证明硫酸乙酰肝素6-O硫酸化在泪腺FGF信号传导中的重要性。改变Hs 2st引起的表型严重得多，但Hs 2st; Hs 6st双突变体完全废除泪腺发育，这表明硫酸乙酰肝素的2-O和6-O硫酸化都有助于FGF信号传导。Hs2st; Hs 6st缺陷协同破坏Fgf 10-Fgfr 2b-硫酸乙酰肝素复合物在细胞表面上的形成，并阻止Fgf 10在外植体培养物中诱导泪腺。重要的是，Hs 2st、Hs 6st双突变体消除了FGF下游ERK信号传导。因此，泪腺发育过程中的Fgf 10-Fgfr 2b信号对硫酸乙酰肝素中O-硫酸基团的含量或排列敏感。据我们所知，这是第一个研究表明，同时删除Hs 2st和Hs 6st表现出深刻的FGF信号转导缺陷在哺乳动物的发展。
Heparan sulfate, an extensively sulfated glycosaminoglycan abundant on cell surface proteoglycans, regulates intercellular signaling through its binding to various growth factors and receptors. In the lacrimal gland, branching morphogenesis depends on the interaction of heparan sulfate with Fgf10-Fgfr2b. To address if lacrimal gland development and FGF signaling depends on 2-O-sulfation of uronic acids and 6-O-sulfation of glucosamine residues, we genetically ablated heparan sulfate 2-O and 6-O sulfotransferases (Hs2st, Hs6st1, and Hs6st2) in developing lacrimal gland. Using a panel of phage display antibodies, we confirmed that these mutations disrupted 2-O and/or 6-O but not N-sulfation of heparan sulfate. The Hs6st mutants exhibited significant lacrimal gland hypoplasia and a strong genetic interaction with Fgf10, demonstrating the importance of heparan sulfate 6-O sulfation in lacrimal gland FGF signaling. Altering Hs2st caused a much less severe phenotype, but the Hs2st;Hs6st double mutants completely abolished lacrimal gland development, suggesting that both 2-O and 6-O sulfation of heparan sulfate contribute to FGF signaling. Combined Hs2st; Hs6st deficiency synergistically disrupted the formation of Fgf10-Fgfr2b-heparan sulfate complex on the cell surface and prevented lacrimal gland induction by Fgf10 in explant cultures. Importantly, the Hs2st;Hs6st double mutants abrogated FGF downstream ERK signaling. Therefore, Fgf10-Fgfr2b signaling during lacrimal gland development is sensitive to the content or arrangement of O-sulfate groups in heparan sulfate. To our knowledge, this is the first study to show that simultaneous deletion of Hs2st and Hs6st exhibits profound FGF signaling defects in mammalian development.