Lack of evidence for caveolin-1 and CD147 interaction before and after bleomycin-induced lung injury
Lack of evidence for caveolin-1 and CD147 interaction before and after bleomycin-induced lung injury
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DOI：
10.1007/s00418-006-0192-3
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发表时间：
2006-11-01
影响因子：
2.3
通讯作者：
Kasper, M.
中科院分区：
文献类型：
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作者：
Barth, K.;Blaesche, R.;Kasper, M.
免疫组织化学和体外研究表明，小窝蛋白-1在肺泡上皮细胞和肺微血管内皮细胞中大量表达，在博莱霉素作用下，肺泡上皮细胞中小窝蛋白-1的表达选择性下调。博莱霉素还可以增强肺细胞中金属蛋白酶及其诱导物CD147/EMMPRIN的表达水平。体外实验数据表明，CD147诱导基质金属蛋白酶的活性受小窝蛋白-1的调控。我们利用兼具I型和II型肺泡上皮细胞特性的大鼠肺泡上皮细胞系R3/1和移植的大鼠肺切片，研究了博莱霉素对小窝蛋白-1、CD147和金属蛋白酶表达的影响。同时，将博莱霉素诱导的大鼠和小鼠肝纤维化的回顾性样本以及野生型和小窝蛋白-1基因敲除动物的样本包括在内，用于免疫组织化学与体外数据的比较。通过RT-PCR、Western印迹分析、MMP2活性测定和免疫细胞化学方法，我们报道了博莱霉素组R3/1细胞小窝蛋白-1的表达下调，CD147、MMP2和-9的表达/活性增加。免疫荧光双标记法显示，小窝蛋白-1和CD147在体外没有共定位。通过对石蜡包埋的精密切割大鼠肺切片和纤维化大鼠肺组织中蛋白质的免疫组织化学研究，证实了体外发现。小窝蛋白-1阴性的增生性ATII细胞对CD147和基质金属蛋白酶-2的免疫反应增强。纤维组织中Caveolin-1阴性的ATI细胞多为CD147阴性。CD147在正常和小窝蛋白1缺陷动物肺组织中的表达差异无统计学意义。结果表明，博莱霉素性肺损伤与肺泡上皮细胞CD147表达和基质金属蛋白酶活性增加有关。此外，我们的数据排除了CD147和肺泡上皮细胞小窝蛋白-1之间的任何功能相互作用。
Immunohistochemical and in vitro studies indicate that caveolin-1, which occurs abundantly in alveolar epithelial type I cells and microvascular endothelial cells of the lung, is selectively downregulated in the alveolar epithelium following exposure to bleomycin. Bleomycin is also known to enhance the expression levels of metalloproteinases and of the metalloproteinase inducer CD147/EMMPRIN in lung cells. Experimental in vitro data has showed that MMP-inducing activity of CD147 is under the control of caveolin-1. We studied the effects of bleomycin on the expression of caveolin-1, CD147 and metalloproteinases using an alveolar epithelial rat cell line R3/1 with properties of both alveolar type I and type II cells and explanted rat lung slices. In parallel, retrospective samples of bleomycin-induced fibrosis in rats and mice as well as samples of wild type and caveolin-1 knockout animals were included for immunohistochemical comparison with in vitro data. Here we report that treatment with bleomycin downregulates caveolin-1 and increases CD147 and MMP-2 and -9 expression/activity in R3/1 cells using RT-PCR, Western blot analysis, MMP-2 activity assay and immunocytochemistry. Immunofluorescence double labeling revealed that caveolin-1 and CD147 were not colocalized in vitro. The in vitro findings were confirmed through immunohistochemical studies of the proteins in paraffin embedded precision-cut rat lung slices and in fibrotic rat lung tissues. The caveolin-1-negative hyperplastic ATII cells exhibited enhanced immunoreactivity for CD147 and MMP-2. Caveolin-1-negative ATI cells of fibrotic samples were mostly CD147 negative. There were no differences in the pulmonary expression of CD147 between the normal and caveolin-1 deficient animals. The results demonstrate that bleomycin-induced lung injury is associated with an increase in CD147 expression and MMP activity, particularly in alveolar epithelial cells. In addition, our data exclude any functional interaction between CD147 and alveolar epithelial caveolin-1.