Profiling heparin-chemokine interactions using synthetic tools
Profiling heparin-chemokine interactions using synthetic tools
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DOI：
10.1021/cb700159m
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发表时间：
2007-11-01
影响因子：
4
通讯作者：
Seeberger, Peter H.
中科院分区：
文献类型：
--
作者：
de Paz, Lose L.;Moseman, E. Ashley;Seeberger, Peter H.
糖胺多聚糖(GAG)，如肝素或硫酸肝素，是趋化因子在体内发挥作用所必需的。趋化因子在白细胞亚群向炎症和淋巴细胞转运部位的募集中起着至关重要的作用。GAG-趋化因子相互作用调节细胞迁移，并决定哪些白细胞亚群进入组织。识别与特定趋化因子结合的准确GAC序列是在分子水平上理解趋化因子功能和开发干扰趋化因子介导的过程的策略的关键。在这里，我们通过使用包含合成肝素低聚糖小文库的肝素微阵列来表征八种趋化因子(CCL21、IL-8、CXCL12、CXCL13、CCL19、CCL25、CCL28和CXCL16)的肝素结合谱。趋化因子与肝素低聚糖的相互作用显著不同：某些趋化因子(如CCL21)与含有GlcNSO3(6-OSO3)-IDOA(2-OSO3)重复单位的六糖强结合，而CCL19不结合，而CXCL12仅弱结合。通过表面等离子体共振实验验证了碳水化合物微阵列的结合结果。体外趋化实验表明，包被完全硫酸化的肝素六糖的树状大分子抑制淋巴细胞向CCL21的迁移。向CXCL12或CCL19的迁移不受影响。这些体外归巢试验表明，多价合成肝素树状大分子通过阻断GAG包膜链上趋化因子浓度梯度的形成，抑制淋巴细胞向某些趋化因子梯度的迁移。这些发现与对循环淋巴细胞的初步活体测量结果一致。本文提出的结果有助于理解Gag-趋化因子的相互作用，这是设计调节趋化因子活性的新药的第一步。
Glycosaminoglycans (GAGs), such as heparin or heparan sulfate, are required for the in vivo function of chemokines. Chemokines play a crucial role in the recruitment of leukocyte subsets to sites of inflammation and lymphocytes trafficking. GAG-chemokine interactions mediate cell migration and determine which leukocyte subsets enter tissues. Identifying the exact GAC sequences that bind to particular chemokines is key to understand chemokine function at the molecular level and develop strategies to interfere with chemokine-mediated processes. Here, we characterize the heparin binding profiles of eight chemokines (CCL21, IL-8, CXCL12, CXCL13, CCL19, CCL25, CCL28, and CXCL16) by employing heparin microarrays containing a small library of synthetic heparin oligosaccharides. The chemokines differ significantly in their interactions with heparin oligosaccharides: While some chemokines, (e.g., CCL21) strongly bind to a hexasaccharide containing the GlcNSO3(6-OSO3)-IdoA(2-OSO3) repeating unit, CCL19 does not bind and CXCL12 binds only weakly. The carbohydrate microarray binding results were validated by surface plasmon resonance experiments. In vitro chemotaxis assays revealed that dendrimers coated with the fully sulfated heparin hexasaccharide inhibit lymphocyte migration toward CCL21. Migration toward CXCL12 or CCL19 was not affected. These in vitro homing assays indicate that multivalent synthetic heparin dendrimers inhibit the migration of lymphocytes toward certain chemokine gradients by blocking the formation of a chemokine concentration gradient on GAG enclothetial chains. These findings are in agreement with preliminary in vivo measurements of circulating lymphocytes. The results presented here contribute to the understanding of GAG-chemokine interactions, a first step toward the design of novel drugs that modulate chemokine activity.