Sulfotransferases in the Synthesis on L-Selectin Ligands

超出提供的空间。在淋巴细胞归巢过程中，L-选择素介导了淋巴细胞与高内皮微静脉的初始黏附。它还在白细胞与内皮细胞的相互作用中发挥作用，这是白细胞向慢性炎症部位运输的基础。L-选择素通过识别HEV表达的一组离散的配体，包括GlyCAM-1，CD34和Podocalysin，发挥凝集素样受体的作用。这些配体含有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。所有这三个修饰都是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与选择素结合的识别决定因素是一种被称为6-磺基SLeX的硫酸化结构，这是一种四糖，在N-乙酰氨基葡萄糖的C-6位上具有硫酸酯。在寻找阐述HEV内这一关键修饰的磺基转移酶的过程中，罗森实验室克隆了一组GlcNAc-6-O-磺基转移酶。其中两种被称为GST-2和GST-3，存在于混合动力汽车中。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。通过在小鼠中破坏L-选择素配体基因，证实了HEC-GlcNAc6ST直接参与了L-选择素配体的形成。HEC-GIcNAc6ST基因敲除小鼠表现出明显但不完全的L选择素HEV表达配体的丢失，以及淋巴细胞归巢到淋巴结的障碍。这笔赠款将继续研究HEC-GlcNAc6ST和相关酶GST-2在淋巴细胞归巢和炎性白细胞运输中的功能。其具体目的是：1)确定HEC-GIcNAc6ST对原位生成的L-选择素配体活性的贡献；2)测定炎症部位激活的内皮细胞中HEC-GlcNAc6ST的表达；3)确定HEC-GlcNAc6ST对慢性炎症模型小鼠白细胞募集和疾病的贡献；以及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，因为这些酶是阻断炎症性疾病的潜在治疗靶点。表演网站========================================Section End===========================================

EXCEED THE SPACE PROVIDED. 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. PERFORMANCE SITE ========================================Section End===========================================