Baghestanian M, Agis H, Bevec D, Bankl H C, Hofbauer R, Kress H G, Butterfield J H, Müller M R, Ashman L K, Füreder W, Willheim M, Lechner K, Valent P
Department of Internal Medicine I, University of Vienna, Austria.
Exp Hematol. 1996 Oct;24(12):1377-86.
Recent data suggest that local overexpression of the tissue-hormone c-kit ligand (stem cell factor [SCF]) is associated with accumulation of mast cells (MCs) and a decrease in expression of c-kit in the accumulated MCs [28]. In the present study, the effects of recombinant human (rh) SCF on expression of c-kit mRNA and c-kit protein in isolated human MCs and a human mast cell line, HMC-1, were analyzed. Incubation of isolated lung MC with rhSCF (100 ng/mL) for 120 minutes resulted in decreased expression of c-kit mRNA (optical density [OD], control: 100% vs. rhSCF: 37%). Almost identical results were obtained with HMC-1 cells (OD, control: 100% vs. rhSCF: 40 to 45%). As assessed by flow cytometry and monoclonal antibodies (mAbs) to c-kit, the SCF-induced decrease of c-kit mRNA in HMC-1 was associated with a substantial decrease in surface expression of c-kit (MFI, control: 100 +/- 21%, vs. MFI in cells incubated with rhSCF [100 ng/mL at 37 degrees C for 12 hours]: 8 +/- 2%, vs. MFI in cells incubated with rhSCF, 100 ng/mL, at 4 degrees C: 34 +/- 3%). The effects of rhSCF on c-kit expression in HMC-1 cells were dose- and time-dependent with maximum effects observed with 10-100 ng/mL of rhSCF after 4 to 12 hours. The SCF-dependent loss of c-kit was also accompanied by a decreased chemotactic response to rhSCF (control: 100%; rhSCF: 71 +/- 2%). This study shows that exposure of human lung MC and HMC-1 cells to recombinant SCF results in downregulation of c-kit mRNA and surface c-kit expression. These data may explain the partial loss of c-kit on MCs in areas of SCF overexpression.
近期数据表明，组织激素c-kit配体（干细胞因子[SCF]）的局部过表达与肥大细胞（MC）的积聚以及积聚的MC中c-kit表达的降低有关[28]。在本研究中，分析了重组人（rh）SCF对分离的人MC和人肥大细胞系HMC-1中c-kit mRNA和c-kit蛋白表达的影响。用rhSCF（100 ng/mL）孵育分离的肺MC 120分钟导致c-kit mRNA表达降低（光密度[OD]，对照：100% vs. rhSCF：37%）。HMC-1细胞也得到了几乎相同的结果（OD，对照：100% vs. rhSCF：40%至45%）。通过流式细胞术和针对c-kit的单克隆抗体（mAb）评估，SCF诱导的HMC-1中c-kit mRNA的降低与c-kit表面表达的显著降低相关（平均荧光强度[MFI]，对照：100±21%，与在37℃用rhSCF[100 ng/mL]孵育12小时的细胞中的MFI相比：8±2%，与在4℃用100 ng/mL rhSCF孵育的细胞中的MFI相比：34±3%）。rhSCF对HMC-1细胞中c-kit表达的影响呈剂量和时间依赖性，在4至12小时后用10 - 100 ng/mL rhSCF观察到最大效应。c-kit的SCF依赖性丧失还伴随着对rhSCF的趋化反应降低（对照：100%；rhSCF：71±2%）。本研究表明，人肺MC和HMC-1细胞暴露于重组SCF会导致c-kit mRNA和表面c-kit表达下调。这些数据可能解释了SCF过表达区域中MC上c-kit的部分丧失。
