NDST2 (N-Deacetylase/N-Sulfotransferase-2) Enzyme Regulates Heparan Sulfate Chain Length
NDST2 (N-Deacetylase/N-Sulfotransferase-2) Enzyme Regulates Heparan Sulfate Chain Length
复制标题
DOI：
10.1074/jbc.m116.744433
复制
发表时间：
2016-09-02
影响因子：
4.8
通讯作者：
Kjellen, Lena
中科院分区：
文献类型：
--
作者：
Deligny, Audrey;Dierker, Tabea;Kjellen, Lena
对由过表达鼠NDST 1和/或NDST 2的HEK 293细胞合成的硫酸乙酰肝素的分析表明，硫酸乙酰肝素的量在NDST 2-过表达细胞中增加，但在NDST 1-过表达细胞中不增加。编码其他生物合成酶或蛋白聚糖核心蛋白的基因的转录表达改变不能解释所观察到的变化。然而，NDST 2在调节硫酸乙酰肝素合成量中的作用通过分析从含有降低水平的多糖的Ndst 2（-/-）小鼠分离的组织中的硫酸乙酰肝素含量来证实。详细的二糖组成分析显示，来自对照和Ndst 2（-/-）组织的硫酸乙酰肝素之间没有主要的结构差异，除了来自脾的硫酸乙酰肝素，其中三硫酸化二糖的相对量在不存在NDST 2的情况下降低。硫酸乙酰肝素聚合酶Ext 1和Ext 2的体内转录表达水平也在很大程度上不受NDST 2水平的影响，这表明除了增加基因转录之外还有一种调节模式。硫酸乙酰肝素多糖链的大小估计表明，单独在NDST 2过表达细胞中增加的链长度可以解释硫酸乙酰肝素含量的增加。一个模型进行了讨论，其中NDST 2特异性底物修饰刺激伸长导致硫酸乙酰肝素链长度增加。
Analysis of heparan sulfate synthesized by HEK 293 cells overexpressing murine NDST1 and/or NDST2 demonstrated that the amount of heparan sulfate was increased in NDST2-but not in NDST1-overexpressing cells. Altered transcript expression of genes encoding other biosynthetic enzymes or proteoglycan core proteins could not account for the observed changes. However, the role of NDST2 in regulating the amount of heparan sulfate synthesized was confirmed by analyzing heparan sulfate content in tissues isolated from Ndst2(-/-) mice, which contained reduced levels of the polysaccharide. Detailed disaccharide composition analysis showed no major structural difference between heparan sulfate from control and Ndst2(-/-) tissues, with the exception of heparan sulfate from spleen where the relative amount of trisulfated disaccharides was lowered in the absence of NDST2. In vivo transcript expression levels of the heparan sulfate-polymerizing enzymes Ext1 and Ext2 were also largely unaffected by NDST2 levels, pointing to a mode of regulation other than increased gene transcription. Size estimation of heparan sulfate polysaccharide chains indicated that increased chain lengths in NDST2-overexpressing cells alone could explain the increased heparan sulfate content. A model is discussed where NDST2-specific substrate modification stimulates elongation resulting in increased heparan sulfate chain length.