期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1991
卷号：88
期号：9
页码：3705-3709
DOI：10.1073/pnas.88.9.3705
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Enkephalins, a group of small peptides with opiate-like activity, have been defined originally as neuropeptides. Recent reports showed, using in situ hybridization, that the enkephalin-encoding gene, proenkephalin A (pEnkA), is expressed in nondifferentiated cells of diverse mesodermal lineages. The transient expression of pEnkA in these tissues during organogenesis suggests that this gene is involved in processes such as differentiation and/or cell proliferation. In situ hybridization revealed that bone and cartilage are among the tissues that express pEnkA most actively during organogenesis. Here we show that pEnkA mRNA is abundant in normal calvaria-derived cells and in osteosarcoma-derived cell lines ROS 17/2.8 and ROS 25/1. In addition, pEnkA-derived peptides are synthesized and secreted by these cells, as revealed by specific RIA. pEnkA expression in ROS cells is decreased by osteogenin, an osteoinductive factor, and by the calcium-regulating hormone, 1,25-dihydroxyvitamin D3, whereas the osteoblastic phenotype marker, alkaline phosphatase, is increased by these factors. These results together with the inhibitory effects of pEnkA-derived peptides on alkaline phosphatase activity in ROS 17/2.8 cells suggest that pEnkA is involved in bone development and provide a model system for further analysis of pEnkA expression during this process.
