Localization of human neutrophil interleukin-8 (CXCL-8) to organelle(s) distinct from the classical granules and secretory vesicles
Localization of human neutrophil interleukin-8 (CXCL-8) to organelle(s) distinct from the classical granules and secretory vesicles
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DOI：
10.1189/jlb.0505248
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发表时间：
2006-03-01
影响因子：
5.5
通讯作者：
Karlsson, Anna
中科院分区：
文献类型：
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作者：
Pellme, Sara;Morgelin, Matthias;Karlsson, Anna
成熟的人中性粒细胞含有少量的白细胞介素-8 [CXC趋化因子配体8（CXCL-8）]，其在促炎活化后显著增加。已经表明，静息的人中性粒细胞的CXCL-8内容物储存在分泌囊泡中。在这里，我们已经使用了分馏技术，它允许这些囊泡的隔离，我们发现，CXCL-8既不与分泌囊泡，也不与任何经典的nenglomerase颗粒的标记物共定位。为了提高系统的分辨率，我们通过脂多糖诱导CXCL-8的产生。刺激8小时后，使用免疫电子显微镜在细胞内观察到CXCL-8。图像显示含有CXCL-8的结构类似于中性粒细胞颗粒，并且这些不同于所有已知的中性粒细胞器，如双重免疫染色所示。此外，CXCL-8细胞器存在于nonstimulated nenglomerulus细胞质，缺乏所有其他已知的颗粒和分泌囊泡的实体。在细胞质的分级分离中，发现CXCL-8与内质网（ER）的标记物钙连接蛋白（calnexin）部分结合。因此，部分CXCL-8可能定位于中性粒细胞的ER或ER样结构。
Mature human neutrophils contain small amounts of interleukin-8 [CXC chemokine ligand 8 (CXCL-8)], which upon proinflammatory activation, increases significantly. It has been suggested that the CXCL-8 content of resting human nentrophils is stored in the secretory vesicles. Here, we have used a fractionation technique, which allows isolation of these vesicles, and we find that CXCL-8 neither colocalizes with the secretory vesicles nor with markers of any of the classical nentrophil granules. To increase resolution in the system, we induced CXCL-8 production by lipopolysaccharide. After 8 h of stimulation, CXCL-8 was visualized within the cell using immunoelectron microscopy. The images revealed CXCL-8-containing stuctures resembling neutrophil granules, and these were distinct from all known neutrophil organelles, as shown by double immunostaining. Further, the CXCL-8 organelle was present in nonstimulated nentrophil cytoplasts, entities lacking all other known granules and secretory vesicles. Upon fractionation of the cytoplasts, CXCL-8 was found to partly cofractionate with calnexin, a marker for endoplasmic reticulum (ER). Thus, part of CXCL-8 may he localized to the ER or ER-like structures in the nentrophil.