Harris Rebecca Louise, van den Berg Carmen Wilma, Bowen Derrick John
Institute of Molecular and Experimental Medicine, Cardiff University School of Medicine, Heath Park, Cardiff CF14 4XN, UK.
Mol Biol Int. 2012;2012:283974. doi: 10.1155/2012/283974. Epub 2012 Aug 2.
Background. The asialoglycoprotein receptor (ASGPR) is a hepatic receptor that mediates removal of potentially hazardous glycoconjugates from blood in health and disease. The receptor comprises two proteins, asialoglycoprotein receptor 1 and 2 (ASGR1 and ASGR2), encoded by the genes ASGR1 and ASGR2. Design and Methods. Using reverse transcription amplification (RT-PCR), expression of ASGR1 and ASGR2 was investigated in human peripheral blood monocytes. Results. Monocytes were found to express ASGR1 and ASGR2 transcripts. Correctly spliced transcript variants encoding different isoforms of ASGR1 and ASGR2 were present in monocytes. The profile of transcript variants from both ASGR1 and ASGR2 differed among individuals. Transcript expression levels were compared with the hepatocyte cell line HepG2 which produces high levels of ASGPR. Monocyte transcripts were 4 to 6 orders of magnitude less than in HepG2 but nonetheless readily detectable using standard RT-PCR. The monocyte cell line THP1 gave similar results to monocytes harvested from peripheral blood, indicating it may provide a suitable model system for studying ASGPR function in this cell type. Conclusions. Monocytes transcribe and correctly process transcripts encoding the constituent proteins of the ASGPR. Monocytes may therefore represent a mobile pool of the receptor, capable of reaching sites remote from the liver.
背景。去唾液酸糖蛋白受体（ASGPR）是一种肝脏受体，在健康和疾病状态下介导从血液中清除潜在有害的糖缀合物。该受体由两种蛋白质组成，即去唾液酸糖蛋白受体1和2（ASGR1和ASGR2），由基因ASGR1和ASGR2编码。设计与方法。使用逆转录扩增（RT-PCR）技术，研究了ASGR1和ASGR2在人外周血单核细胞中的表达情况。结果。发现单核细胞表达ASGR1和ASGR2转录本。单核细胞中存在编码ASGR1和ASGR2不同异构体的正确剪接的转录本变体。ASGR1和ASGR2的转录本变体谱在个体之间存在差异。将转录本表达水平与产生高水平ASGPR的肝细胞系HepG2进行比较。单核细胞转录本比HepG2中的低4至6个数量级，但使用标准RT-PCR仍可轻松检测到。单核细胞系THP1的结果与从外周血中分离的单核细胞相似，表明它可能为研究该细胞类型中ASGPR的功能提供一个合适的模型系统。结论。单核细胞转录并正确加工编码ASGPR组成蛋白的转录本。因此，单核细胞可能代表受体的一个流动库，能够到达远离肝脏的部位。
