A previously unrecognized protein-protein interaction between TWEAK and CD163:: Potential biological implications
A previously unrecognized protein-protein interaction between TWEAK and CD163:: Potential biological implications
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DOI：
10.4049/jimmunol.178.12.8183
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发表时间：
2007-06-15
影响因子：
4.4
通讯作者：
Pasqualini, Renata
中科院分区：
文献类型：
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作者：
Bover, Laura C.;Cardo-Vila, Marina;Pasqualini, Renata
TWEAK（TNF样弱凋亡诱导剂）是TNF超家族成员，参与多种机制。虽然成纤维细胞生长因子诱导型14（Fn 14）/TweakR已被报道为其受体，但尚未识别的表面分子可能调节TWEAK功能。因此，我们着手通过筛选组合肽文库来鉴定TWEAK结合蛋白。含有与TWEAK特异性结合的共有基序（WXDDG）的环肽。这些肽类似于CD 163，其是清道夫受体富含半胱氨酸的结构域家族成员，仅限于单核细胞/巨噬细胞谱系，并负责循环触珠蛋白-血红蛋白（Hp-Hb）复合物的摄取。序列分析表明，TWEAK模拟CD 163天然配体（Hp-Hb）。因此，我们显示了剂量依赖性TWEAK与CD 163的结合和抗CD 163 Ab的阻断。在竞争测定中，可溶性CD 163和Fn 14/ TweakR两者都能够分别竞争TWEAK与包被的Fn 14/TweakR或CD 163的结合。流式细胞术和免疫荧光测定显示，人单核细胞（Fnl 4/TweakR阴性和CD 163阳性）结合TWEAK，从而阻断CD 163的识别并降低这些细胞中由特异性mAb介导的活化。我们证明单核细胞可以从上清液中隔离TWEAK，从而防止肿瘤细胞凋亡;这种作用通过与模拟CD 163的肽或与mAb抗CD 163预孵育而恢复，表明特异性。最后，我们表明，重组人TWEAK与CD 163转染的中国仓鼠卵巢细胞的结合受到抑制的存在下，无论是未标记的TWEAK或Hp血红蛋白复合物。总之，这些数据与CD 163在病理条件下充当TWEAK清除剂或在缺乏Fnl 4/TweakR的细胞中充当TWEAK的替代受体的假设一致。
TWEAK (TNF-like weak inducer of apoptosis) is a TNF superfamily member implicated in several mechanisms. Although fibroblast growth factor inducible 14 (Fn14)/TweakR has been reported as its receptor, an as yet unrecognized surface molecule(s) might modulate TWEAK function(s). Thus, we set out to identify TWEAK-binding proteins by screening a combinatorial peptide library. Cyclic peptides containing a consensus motif (WXDDG) bound to TWEAK specifically. These peptides were similar to CD163, a scavenger receptor cysteine-rich domain family member, restricted to the monocyte/ macrophage lineage and responsible for the uptake of circulating haptoglobin-hemoglobin (Hp-Hb) complexes. Sequence profile analysis suggested that TWEAK mimicked the CD163 natural ligand (Hp-Hb). Consistently, we show dose-dependent TWEAK binding to CD163 and blockade by an anti-CD163 Ab. In a competition assay, both soluble CD163 and Fn14/ TweakR were able to compete off TWEAK binding to coated Fnl4/TweakR or CD163, respectively. Flow-cytometry and immunofluorescence assays showed that human monocytes (Fnl4/TweakR negative and CD163 positive) bind TWEAK, thus blocking the recognition of CD163 and reducing the activation mediated by a specific mAb in these cells. We demonstrate that monocytes can sequester TWEAK from supernatants, thus preventing tumor cell apoptosis; this effect was reverted by preincubation with the peptide mimicking CD163 or with a mAb anti-CD163, indicating specificity. Finally, we show that recombinant human TWEAK binding to CD163-transfected Chinese hamster ovary cells is inhibited by the presence of either unlabeled TWEAK or the Hp-Hb complex. Together, these data are consistent with the hypothesis that CD163 either acts as a TWEAK scavenger in pathological conditions or serves as an alternate receptor for TWEAK in cells lacking Fnl4/TweakR.