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（HEV）的初始粘附 在淋巴细胞归巢的过程中。它还在白细胞-内皮细胞相互作用中起作用， 将白细胞运送到慢性炎症部位。L-选择素作为一种凝集素样受体， 识别HEV表达的配体的离散集合，包括GlyCAM-1、CD 34和足糖萼蛋白。这些 配体带有O-连接的糖链，其被硫酸化、岩藻糖基化和唾液酸化。所有这三 需要进行修饰以获得L-选择素的最佳识别。GlyCAM- 1和GlyCAM-2的详细分析 CD 34已经揭示了L-选择素结合的识别决定簇是一种称为6-氨基-3-甲基-N-甲基-N-硫代磷酸酯的硫酸化结构。 磺基sLex，一种在N-乙酰葡糖胺的C-6位上具有硫酸酯的四糖。在 罗森实验室为了寻找在戊型肝炎病毒中阐述这种关键修饰的磺基转移酶， 克隆了GlcNAc-6-O-磺基转移酶家族。其中两种，称为GST-2和GST-3，存在于 HEV。GST-3被命名为HEC-GlcNAc 6ST，因为其在高表达细胞中的高度限制性表达。 内皮细胞（HEC）的HEV。HEC-GlcNAc 6ST直接参与L-选择素的表达 通过在小鼠中破坏该基因已经建立了配体。HEC-GlcNAc 6ST敲除小鼠表现出 HEV表达的L-选择素配体显著但不完全丧失，淋巴细胞受损 回到淋巴结目前的拨款将继续HEC-GlcNAc 6ST和相关的研究。 GST-2在淋巴细胞归巢和炎症性白细胞中的功能 贩卖人口具体目的是：1）确定HEC-GlcNAc 6ST对L-半乳糖苷酶活性的贡献。 原位产生的选择素配体; 2）测定HEC-GlcNAc 6ST在活化的HEC-GlcNAc 6ST中的表达， 3）确定HEC-GlcNAc 6ST对白细胞的贡献 在慢性炎症小鼠模型中的募集和疾病;和4）为了确定 GST-2与L-选择素配体的产生有关。对这些磺基转移酶的进一步了解， 相当大的生物医学相关性，因为这些酶是潜在的治疗靶点， 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.