Yoshida H, Kondratenko N, Green S, Steinberg D, Quehenberger O
University of California, San Diego, Department of Medicine, 0682, 9500 Gilman Drive, La Jolla, CA 92093, USA.
Biochem J. 1998 Aug 15;334 ( Pt 1)(Pt 1):9-13. doi: 10.1042/bj3340009.
A new receptor for oxidized low-density lipoprotein (LDL), lectin-like oxidized LDL receptor-1 (LOX-1), has recently been cloned from bovine endothelial cells and human lung. A limited tissue-distribution study suggested that the protein was mainly produced by the vascular endothelium. In the present study we demonstrate that LOX-1 is also expressed in macrophages, where it may function as a scavenger receptor. LOX-1 was not detected in undifferentiated THP-1 cells or in freshly isolated human blood monocytes. However, mature human monocyte-derived macrophages and differentiated THP-1 cells showed high levels of LOX-1 transcripts. Consistent with these results, immunofluorescence staining and FACS analysis demonstrated that LOX-1 protein is expressed on the plasma membrane of macrophages. Western-blot analysis of membranes from macrophages (but not those from monocytes) identified a single band, with an apparent molecular mass of about 40 kDa, that displayed oxidized LDL-binding activity. These results suggest that differentiation induces the expression of LOX-1 in macrophages, where it may play a role as a scavenger receptor and/or a receptor for oxidized LDL.
一种新的氧化型低密度脂蛋白（LDL）受体，即凝集素样氧化型LDL受体-1（LOX-1），最近已从牛内皮细胞和人肺中克隆出来。一项有限的组织分布研究表明，该蛋白主要由血管内皮产生。在本研究中，我们证明LOX-1也在巨噬细胞中表达，在那里它可能作为一种清道夫受体发挥作用。在未分化的THP-1细胞或新鲜分离的人血单核细胞中未检测到LOX-1。然而，成熟的人单核细胞衍生的巨噬细胞和分化的THP-1细胞显示出高水平的LOX-1转录本。与这些结果一致，免疫荧光染色和流式细胞术分析表明，LOX-1蛋白在巨噬细胞的质膜上表达。对巨噬细胞膜（而非单核细胞膜）进行的蛋白质印迹分析鉴定出一条单带，其表观分子量约为40 kDa，具有氧化型LDL结合活性。这些结果表明，分化诱导巨噬细胞中LOX-1的表达，在那里它可能作为清道夫受体和/或氧化型LDL受体发挥作用。
