Oates T W, Xie J F, Clinton S, Hoang A M, Graves D T, Cochran D L
Department of Periodontics, University of Texas Health Science Center, San Antonio 78284, USA.
J Dent Res. 1998 Oct;77(10):1791-8. doi: 10.1177/00220345980770100601.
The responses of cells to the distinct PDGF isoforms have been correlated directly to the relative numbers of specific PDGF receptor subunits on the cell surface. The modulation of PDGF-alpha receptor subunits, the major subunit expressed in human periodontal ligament (PDL) cells, by cytokines present in the periodontal wound site, such as interleukin-1 (IL-1), may be an important factor influencing regenerative outcomes. The purpose of the present study was to examine the effects of IL-1 beta on PDGF-alpha receptor subunit expression in human PDL cells. Primary cultures of human PDL cells were treated with IL-1 beta over a range of concentrations. We assessed PDGF-alpha receptor subunits by examining the mitogenic responses of cells to PDGF-AA, specific binding of 125I-labeled PDGF-AA, immunofluorescent analysis of PDGF-alpha receptor subunits, and PDGF-alpha receptor subunit mRNA levels using Northern blot analysis. The results demonstrate a significant concentration-dependent decrease in 3H-thymidine incorporation in response to PDGF-AA following IL-1 beta treatment (p < 0.001). This decreased response correlated directly with IL-1-induced decreases in 125I-labeled PDGF-AA binding (p < 0.01), the numbers of immunolabeled PDGF-alpha receptor subunits, and in PDGF-alpha receptor subunit mRNA levels. However, when combined with TGF-beta, IL-1 beta did not show additional down-regulation in proliferative response to PDGF-AA or PDGF-alpha receptor subunits beyond that achieved with these factors individually. These experiments identify IL-1 beta, along with TGF-beta, as significant inhibitors of PDGF stimulation in human PDL cells, acting through the down-regulation of PDGF-alpha receptor subunit expression.
细胞对不同血小板衍生生长因子（PDGF）亚型的反应已直接与细胞表面特定PDGF受体亚基的相对数量相关联。牙周伤口部位存在的细胞因子，如白细胞介素-1（IL-1），对人牙周膜（PDL）细胞中表达的主要亚基PDGF-α受体亚基的调节，可能是影响再生结果的一个重要因素。本研究的目的是检测IL-1β对人PDL细胞中PDGF-α受体亚基表达的影响。用人PDL细胞的原代培养物在一系列浓度下用IL-1β处理。我们通过检测细胞对PDGF-AA的促有丝分裂反应、125I标记的PDGF-AA的特异性结合、PDGF-α受体亚基的免疫荧光分析以及使用Northern印迹分析检测PDGF-α受体亚基mRNA水平来评估PDGF-α受体亚基。结果表明，IL-1β处理后，对PDGF-AA的3H-胸腺嘧啶掺入量显著呈浓度依赖性降低（p<0.001）。这种降低的反应与IL-1诱导的125I标记的PDGF-AA结合减少（p<0.01）、免疫标记的PDGF-α受体亚基数量以及PDGF-α受体亚基mRNA水平直接相关。然而，当与转化生长因子-β（TGF-β）联合使用时，IL-1β在对PDGF-AA或PDGF-α受体亚基的增殖反应中并未显示出比单独使用这些因子时更大的下调作用。这些实验确定IL-1β与TGF-β一样，是人类PDL细胞中PDGF刺激的重要抑制剂，通过下调PDGF-α受体亚基表达发挥作用。
