Sulfotransferases in the Synthesis on L-Selectin Ligands

L-选择素介导淋巴细胞与淋巴结高内皮微静脉的初始黏附 在淋巴细胞归巢的过程中。它还在白细胞与内皮细胞的相互作用中发挥作用。 白细胞向慢性炎症部位的运输。L-选择素通过以下途径发挥凝集素样受体的作用 识别HEV表达的一组离散的配体，包括GlyCAM-1、CD34和Podocalyin。这些 配体带有O-连接的碳水化合物链，这些碳水化合物链是硫化、岩藻糖化和唾液酸化的。这三个都是 L-选择素需要进行修改才能进行最佳识别。详细分析GlyCAM-1和 CD34揭示了L-选择素结合的片状识别决定因素是一种被称为6-硫酸盐的结构。 Slex是一种四糖，在N-乙酰氨基葡萄糖的C-6位上有一个硫酸酯。在 在HEV中寻找阐述这一关键修饰的磺基转移酶，罗森实验室已经 克隆了GlcNAc-6-O-磺基转移酶家族。其中两个，称为GST-2和GST-3，存在于 混合动力车。GST-3被命名为HEC-GlcNAc6ST，因为它在高表达 戊型肝炎病毒内皮细胞。HEC-GlcNAc6ST直接参与L-选择素的表达 通过破坏小鼠的这种基因，已经建立了配体。HEC-GIcNAc6ST基因敲除小鼠表现出 戊型肝炎病毒表达的L-选择素配体显著但不完全丢失和淋巴细胞损伤 归巢到淋巴结。目前的拨款将继续研究HEC-GlcNAc6ST和相关的 GST-2酶在淋巴细胞归巢和炎性白细胞中的作用 贩卖人口。具体目的是：1)确定HEC-GIcNAc6ST对L活动的贡献- 2)检测活化HEC-GlcNAc6ST的表达 炎症部位的内皮细胞；3)测定HEC-GlcNAc6ST对白细胞的贡献 在慢性炎症小鼠模型中的募集和疾病；以及4)确定 GST-2能够生成L-选择素配体。对这些磺基转移酶有了进一步的了解 相当大的生物医学相关性，因为这些酶是潜在的阻断治疗靶点 炎症性疾病。

L-selectin mediates the initial adhesion of lymphocytes to high endothelial venules (HEV) in lymph nodes during the process of lymphocyte homing. It also functions in leukocyte-endothelial interactions underlying the trafficking of leukocytes into chronic inflammatory sites. L-selectin functions as a lectin-like receptor by recognizing a discrete set of HEV-expressed ligands including GlyCAM-1, CD34, and podocalyxin. These ligands bear O-linked carbohydrate chains that are sulfated, fucosylated and sialylated. All three of these modifications are required for optimal recognition by L-selectin. A detailed analysis of GlyCAM- 1 and CD34 has revealed that tile recognition determinant for L-selectin binding is a sulfated structure known as 6- sulfo sLex, a tetrasaccharide that possesses a sulfate ester on the C-6 position of N-acetylglucosamine. In the search for the sulfotransferase that elaborates this critical modification within HEV, the Rosen laboratory has cloned a family of GlcNAc-6-O-sulfotransferases. Two of these, known as GST-2 and GST-3, are present in HEV. GST-3 has been given the name HEC-GlcNAc6ST because of its highly restricted expression in high endothelial cells (HEC) of HEV. The direct involvement of HEC-GlcNAc6ST in elaborating L-selectin ligands has been established by disrupting this gene in mice. HEC-GIcNAc6ST knockout mice exhibit a significant but incomplete loss of HEV-expressed ligands for L-selectin and an impairment of lymphocyte homing to lymph nodes. The present grant will continue the study of HEC-GlcNAc6ST and the related enzyme, GST-2, with respect to their functions in lymphocyte homing and inflammatory leukocyte trafficking. The specific aims are: 1) To determine the contribution of HEC-GIcNAc6ST to the activity of L- selectin ligands generated in situ; 2) To determine the expression of HEC-GlcNAc6ST in activated endothelium at sites of inflammation; 3) To determine the contribution of HEC-GlcNAc6ST to leukocyte recruitment and disease in mouse models of chronic inflammation; and 4) To determine the contribution of GST-2 to the generation of L-selectin ligands. Gaining further understanding of these sulfotransferases has considerable biomedical relevance, because these enzymes are potential therapeutic targets for blocking inflammatory diseases.