Sulfotransferases in the Synthesis on L-Selectin Ligands

L-选择素配体合成中的磺基转移酶

• 批准号: 7006660
• 负责人: STEVEN D ROSEN
• 金额: $ 31.01万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN FRANCISCO
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-01-01 至 2007-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7006660
• 关键词: Sulfotransferases; Synthesis; Selectin; Ligands

DESCRIPTION (provided by applicant): 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.

描述（申请人提供）：L-选择素在淋巴细胞归巢过程中介导淋巴细胞与淋巴结中高内皮微静脉（HEV）的初始粘附。它还在白细胞-内皮相互作用中发挥作用，从而将白细胞运输到慢性炎症部位。 L-选择素通过识别一组离散的 HEV 表达的配体（包括 GlyCAM-1、CD34 和足萼蛋白）发挥凝集素样受体的作用。这些配体带有硫酸化、岩藻糖基化和唾液酸化的 O-连接碳水化合物链。所有这三种修饰都是 L-选择素最佳识别所必需的。对 GlyCAM-1 和 CD34 的详细分析表明，L-选择素结合的识别决定簇是一种称为 6-磺基 sLex 的硫酸化结构，它是一种在 N-乙酰氨基葡萄糖的 C-6 位上具有硫酸酯的四糖。在寻找在 HEV 中实现这一关键修饰的磺基转移酶的过程中，Rosen 实验室克隆了一个 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 中。 GST-3 被命名为 HEC-GlcNAc6ST，因为它在 HEV 的高内皮细胞 (HEC) 中表达高度受限。通过破坏小鼠体内的该基因，已确定 HEC-GlcNAc6ST 直接参与 L-选择素配体的制作。 HEC-GlcNAc6ST 敲除小鼠表现出 HEV 表达的 L-选择素配体显着但不完全丧失，并且淋巴细胞归巢至淋巴结的能力受损。目前的资助将继续研究 HEC-GlcNAc6ST 和相关酶 GST-2 在淋巴细胞归巢和炎症白细胞运输中的功能。具体目标是：1）确定HEC-GlcNAc6ST对原位产生的L-选择素配体活性的贡献； 2) 测定炎症部位活化内皮细胞中HEC-GlcNAc6ST的表达； 3) 确定 HEC-GlcNAc6ST 对慢性炎症小鼠模型白细胞募集和疾病的贡献； 4)确定GST-2对L-选择素配体生成的贡献。进一步了解这些磺基转移酶具有相当大的生物医学意义，因为这些酶是阻止炎症性疾病的潜在治疗靶点。