Expression of multiple chondroitin/dermatan sulfotransferases in the neurogenic regions of the embryonic and adult central nervous system implies that complex chondroitin sulfates have a role in neural stem cell maintenance
Expression of multiple chondroitin/dermatan sulfotransferases in the neurogenic regions of the embryonic and adult central nervous system implies that complex chondroitin sulfates have a role in neural stem cell maintenance
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DOI：
10.1634/stemcells.2007-0448
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发表时间：
2008-01-01
期刊：
影响因子：
5.2
通讯作者：
Faissner, Andreas
中科院分区：
文献类型：
--
作者：
Akita, Kaoru;von Holst, Alexander;Faissner, Andreas
软骨素/硫酸皮肤素磺基转移酶（C/D-ST）是软骨素/硫酸皮肤素（CS/DS）链中多种硫酸化结构合成的基础。最近的报告表明，CS/DS聚合物上的特定硫酸化结构参与神经干细胞增殖的调节。在这里，我们研究了C/D-STs在胚胎和成年小鼠中枢神经系统的神经原性区域的基因表达谱。使用逆转录-聚合酶链反应分析，所有目前已知的C/D-ST检测在背侧和腹侧端脑的胚胎第13天（E13）的小鼠胚胎，除了软骨素4-O-磺基转移酶（C4 ST）-3。原位杂交C4 ST-1，皮肤素4-O-磺基转移酶-1，软骨素6-O-磺基转移酶（C6 ST）-1和-2，和糖醛酸2-O-磺基转移酶揭示了这些磺基转移酶基因在前脑的胚胎生发区的细胞表达。多个C/D-ST的表达维持在成体神经干细胞龛中的细胞上。作为神经球培养的神经干细胞保持这些酶的表达。与C/D-ST的基因表达模式一致，二糖分析显示，神经球和E13小鼠脑细胞合成的CS/DS链含有单硫酸化，但也含有大量的二硫酸化二糖单元。在功能上，氯酸钠硫酸化的抑制导致神经球数量的显著的剂量依赖性减少，这不能通过添加单独的纯化的糖胺聚糖（GAG）链（包括肝素）来挽救。这些发现反对神经干细胞维持中GAG链的简单的基于电荷的机制。C/D-ST的协同活性可能允许在神经干细胞周围的细胞外微环境中用二硫代硫酸化CS/DS链对CS/DS蛋白聚糖进行适应性修饰。
Chondroitin/dermatan sulfotransferases (C/D-STs) underlie the synthesis of diverse sulfated structures in chondroitin/dermatan sulfate (CS/DS) chains. Recent reports have suggested that particular sulfated structures on CS/DS polymers are involved in the regulation of neural stem cell proliferation. Here, we examined the gene expression profile of C/D-STs in the neurogenic regions of embryonic and adult mouse central nervous system. Using reverse transcription-polymerase chain reaction analysis, all presently known C/D-STs were detected in the dorsal and ventral telencephalon of the embryonic day 13 (E13) mouse embryo, with the exception of chondroitin 4-O-sulfotransferase (C4ST)-3. In situ hybridization for C4ST-1, dermatan 4-O-sulfotransferase-1, chondroitin 6-O-sulfotransferase (C6ST)-1 and -2, and uronosyl 2-O-sulfotransferase revealed a cellular expression of these sulfotransferase genes in the embryonic germinal zones of the forebrain. The expression of multiple C/D-STs is maintained on cells residing in the adult neural stem cell niche. Neural stem cells cultured as neurospheres maintained the expression of these enzymes. Consistent with the gene expression pattern of C/D-STs, disaccharide analysis revealed that neurospheres and E13 mouse brain cells synthesized CS/DS chains containing monosulfated, but also significant amounts of disulfated, disaccharide units. Functionally, the inhibition of sulfation with sodium chlorate resulted in a significant, dose-dependent decrease in neurosphere number that could not be rescued by the addition of individual purified glycosaminoglycan (GAG) chains, including heparin. These findings argue against a simple charge-based mechanism of GAG chains in neural stem cell maintenance. The synergistic activities of C/D-STs might allow for the adaptive modification of CS/DS proteoglycans with diversely sulfated CS/DS chains in the extracellular microenvironment that surrounds neural stem cells.