The IP-10 chemokine binds to a specific cell surface heparan sulfate site shared with platelet factor 4 and inhibits endothelial cell proliferation.
The IP-10 chemokine binds to a specific cell surface heparan sulfate site shared with platelet factor 4 and inhibits endothelial cell proliferation.
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DOI：
10.1084/jem.182.1.219
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发表时间：
1995-07-01
期刊：
影响因子：
--
通讯作者：
Leder P
中科院分区：
文献类型：
--
作者：
Luster AD;Greenberg SM;Leder P
IP-10是细胞因子趋化因子家族的一员，可在干扰素、γ干扰素和脂多糖的刺激下在多种细胞中诱导表达。包括IP-10在内的许多趋化因子所共有的自我聚集现象阻碍了对特定IP-10受体的识别。使用IP-10碱性磷酸酶融合蛋白，幸运地阻止了这种自我聚集，我们已经确定了包括内皮细胞、上皮细胞和造血细胞在内的各种细胞上的IP-10结合位点。该结合位点的Kd为25 nM，可被重组小鼠或人IP-10抑制，并依赖于细胞表面硫酸乙酰肝素蛋白多糖(HSPG)的存在。这一结论是基于以下发现：(A)IP-10与细胞的结合被肝素和肝素硫酸盐抑制；(B)对1M的氯化钠洗涤敏感；(C)用肝素酶和胰酶处理消除；(D)在不表达细胞表面HSPG的突变CHO细胞中缺失。而IL-8、单核细胞趋化蛋白-1、RANTES、单核细胞炎性蛋白(MIP)-1α或MIP-1β不能有效地与IP-10竞争结合到细胞表面。此外，IP-10与PF4一样具有抑制内皮细胞增殖的能力(IC50=150 nM)。这些研究显示了趋化因子和HSPG相互作用的特异性，它们将IP-10和PF4定义为具有HSPG结合位点和血管抑制特性的趋化因子的不同子集。
IP-10 is a member of the chemokine family of cytokines and is induced in a variety of cells in response to interferon gamma and lipopolysaccharide. The self-aggregation common to many chemokines, including IP-10, has hindered the identification of a specific IP-10 receptor. Using an IP-10 alkaline phosphatase fusion protein that fortuitously blocks this self-aggregation, we have identified an IP-10 binding site on a variety of cells including endothelial, epithelial, and hematopoietic cells. This binding site has a Kd of 25 nM, is inhibited by recombinant murine or human IP-10, and is dependent on the presence of cell surface heparan sulfate proteoglycans (HSPG). This conclusion is based on the findings that IP-10 binding to cells is: (a) inhibited by heparin and heparan sulfate; (b) sensitive to a 1 M NaCl wash; (c) eliminated by treatment with heparinase and trypsin; and (d) absent on mutant CHO cells that do not express cell surface HSPG. Platelet factor 4 (PF4), but not IL-8, monocyte chemoattractant protein- 1, RANTES, monocyte inflammatory protein (MIP)-1 alpha, or MIP-1 beta, can compete effectively with IP-10 for binding to the cell surface. Furthermore, IP-10 shares with PF4 the ability to inhibit endothelial cell proliferation (IC50 = 150 nM). These studies demonstrate specificity in the interaction of chemokines and HSPG, and they define IP-10 and PF4 as a distinct subset of chemokines sharing an HSPG- binding site and angiostatic properties.