Significant decrease in alpha1,3-linked fucose in association with increase in 6-sulfated N-acetylglucosamine in peripheral lymph node addressin of FucT-VII-deficient mice exhibiting diminished lymphocyte homing.
Significant decrease in alpha1,3-linked fucose in association with increase in 6-sulfated N-acetylglucosamine in peripheral lymph node addressin of FucT-VII-deficient mice exhibiting diminished lymphocyte homing.
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DOI：
10.1093/glycob/cwl077
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发表时间：
2007-03
期刊：
影响因子：
4.3
通讯作者：
N. Hiraoka;B. Petryniak;H. Kawashima;J. Mitoma;T. Akama;M. Fukuda;J. Lowe;M. Fukuda
中科院分区：
文献类型：
--
作者：
N. Hiraoka;B. Petryniak;H. Kawashima;J. Mitoma;T. Akama;M. Fukuda;J. Lowe;M. Fukuda
淋巴细胞归巢是通过淋巴细胞上的L-选择素与外周和肠系膜淋巴结的高内皮微静脉（HEV）上存在的L-选择素配体结合来介导的。L-选择素配体是特异性O-连接的碳水化合物，6-磺基唾液酸刘易斯X，由唾液酸化、岩藻糖基化和硫酸化聚糖组成。岩藻糖基转移酶-VII（FucT-VII）的去除导致淋巴细胞归巢几乎完全丧失，但尚未对FucT-VII缺失小鼠进行碳水化合物的结构分析。为了确定在FucT-VII缺陷小鼠中观察到的功能丧失是否由碳水化合物的结构变化引起，我们阐明了GlyCAM-1（一种主要的L-选择素反受体）的碳水化合物结构。我们的研究结果表明，大多数α 1，3-岩藻糖基化结构的6-磺基唾液酸刘易斯X是缺乏和6-磺基N-乙酰乳糖胺增加突变小鼠。令人惊讶的是，与黑森布库斯凝集素柱结合的6 '-硫酸化半乳糖（Gal）的量也增加。我们发现这些含有6 '-硫酸化半乳糖的寡糖的结构与硫酸角质素磺基转移酶（KSST）合成的寡糖的结构几乎相同。然后，我们发现KSST的过表达抑制了中国仓鼠卵巢（CHO）细胞上sialyl刘易斯X的表达，这些细胞被工程化以表达sialyl刘易斯X。此外，与表达6-磺基唾液酸刘易斯X的模拟转染CHO细胞相比，这些细胞中的KSST表达抑制淋巴细胞滚动。6 '-磺基唾液酸刘易斯X既不能在来自表达KSST和FucT-VII的CHO细胞的GlyCAM-1中发现，也不能在来自小鼠戊型肝炎病毒的GlyCAM-1中发现。这些结果结合在一起表明，KSST与FucT-VII竞争相同的受体底物，并通过抑制α 1，3-岩藻糖基化下调L-选择素配体的合成。
Lymphocyte homing is mediated by binding of L-selectin on lymphocytes with L-selectin ligands present on high-endothelial venules (HEV) of peripheral and mesenteric lymph nodes. L-selectin ligands are specific O-linked carbohydrates, 6-sulfo sialyl Lewis X, composed of sialylated, fucosylated, and sulfated glycans. Abrogation of fucosyltransferase-VII (FucT-VII) results in almost complete loss of lymphocyte homing, but structural analysis of carbohydrates has not been carried out on FucT-VII null mice. To determine whether functional losses seen in FucT-VII null mice are caused by structural changes in carbohydrates, we elucidated the carbohydrate structure of GlyCAM-1, a major L-selectin counter-receptor. Our results show that most alpha1,3-fucosylated structures in 6-sulfo sialyl Lewis X are absent and 6-sulfo N-acetyllactosamine is increased in the mutant mice. Surprisingly, the amount of 6'-sulfated galactose (Gal) that bound to Sumbucus nigra agglutinin column was also increased. We found that structures of those oligosaccharides containing 6'-sulfated Gal are almost identical to those synthesized by keratan sulfate sulfotransferase (KSST). We then showed that overexpression of KSST suppresses the expression of sialyl Lewis X on Chinese hamster ovary (CHO) cells engineered to express sialyl Lewis X. Moreover, KSST expression in those cells suppressed lymphocyte rolling compared with mock-transfected CHO cells expressing 6-sulfo sialyl Lewis X. 6'-Sulfo sialyl Lewis X can neither be found in GlyCAM-1 from CHO cells expressing both KSST and FucT-VII nor be found in GlyCAM-1 from HEV of mice. These results combined together suggest that KSST competes with FucT-VII for the same acceptor substrate and downregulates the synthesis of L-selectin ligand by inhibiting alpha1,3-fucosylation.