Lee Heeseob, Wang Ping, Hoshino Hitomi, Ito Yuki, Kobayashi Motohiro, Nakayama Jun, Seeberger Peter H, Fukuda Minoru
Tumor Microenvironment Program, Glycobiology Unit, Cancer Center, Burnham Institute for Medical Research, La Jolla, CA 92037, USA.
Glycobiology. 2008 Jul;18(7):549-58. doi: 10.1093/glycob/cwn037. Epub 2008 May 5.
Helicobacter pylori infects over half of the world's population and is thought to be a leading cause of gastric ulcer, gastric carcinoma, and gastric malignant lymphoma of mucosa-associated lymphoid tissue type. Previously, we reported that a gland mucin (MUC6) present in the lower portion of the gastric mucosa containing alpha1,4-N-acetylglucosamine (alpha1,4GlcNAc)-capped core 2-branched O-glycans suppresses H. pylori growth by inhibiting the synthesis of alpha-glucosyl cholesterol, a major constituent of the H. pylori cell wall (Kawakubo et al. 2004. Science. 305:1003-1006). Therefore, we cloned the genomic DNA encoding cholesterol alpha-glucosyltransferase (HP0421) and expressed its soluble form in Escherichia coli. Using this soluble HP0421, we show herein that HP0421 sequentially acts on uridine diphosphoglucose and cholesterol in an ordered Bi-Bi manner. We found that competitive inhibition of HP0421 by alpha1,4GlcNAc-capped core 2-branched O-glycan is much more efficient than noncompetitive inhibition by newly synthesized alpha-glucosyl cholesterol. Utilizing synthetic oligosaccharides, alpha-glucosyl cholesterol, and monosaccharides, we found that alpha1,4GlcNAc-capped core 2-branched O-glycan most efficiently inhibits H. pylori growth. These findings together indicate that alpha1,4GlcNAc-capped O-glycans suppress H. pylori growth by inhibiting HP0421, and that alpha1,4GlcNAc-capped core 2 O-glycans may be useful to treat patients infected with H. pylori.
幽门螺杆菌感染了全球超过一半的人口，被认为是胃溃疡、胃癌以及黏膜相关淋巴组织型胃恶性淋巴瘤的主要病因。此前，我们报道过胃黏膜下部存在的一种腺黏蛋白（MUC6）含有α1,4-N-乙酰葡糖胺（α1,4GlcNAc）封端的核心2分支O-聚糖，它通过抑制幽门螺杆菌细胞壁的主要成分α-葡糖基胆固醇的合成来抑制幽门螺杆菌的生长（河久保等人，2004年。《科学》。305:1003 - 1006）。因此，我们克隆了编码胆固醇α-葡糖基转移酶（HP0421）的基因组DNA，并在大肠杆菌中表达了其可溶性形式。利用这种可溶性HP0421，我们在此表明HP0421以有序的双底物双产物方式依次作用于尿苷二磷酸葡萄糖和胆固醇。我们发现，α1,4GlcNAc封端的核心2分支O-聚糖对HP0421的竞争性抑制比新合成的α-葡糖基胆固醇的非竞争性抑制效率高得多。利用合成寡糖、α-葡糖基胆固醇和单糖，我们发现α1,4GlcNAc封端的核心2分支O-聚糖最有效地抑制幽门螺杆菌的生长。这些发现共同表明，α1,4GlcNAc封端的O-聚糖通过抑制HP0421来抑制幽门螺杆菌的生长，并且α1,4GlcNAc封端的核心2 O-聚糖可能对治疗幽门螺杆菌感染的患者有用。
