Takeshita A, Hanazawa S, Amano S, Matumoto T, Kitano S
Department of Oral Microbiology, Meikai University School of Dentistry, Saitama, Japan.
J Immunol. 1993 Feb 15;150(4):1554-62.
Recent studies demonstrated that platelet-derived growth factor-inducible JE is an inflammatory cytokine that directs chemotaxis of monocytes, and is a homolog of monocyte chemoattractant protein-1, which is a human monocyte chemotactic factor. Migration and accumulation of monocyte lineage cells in bone tissue sites are very important for the recruitment of multinucleate osteoclasts, because the origin of osteoclasts is derived from monocyte lineage cells in hemopoietic cells. Because IL-1 is a potent regulator in bone remodeling, we examined whether IL-1 beta induces JE expression in a clonal mouse osteoblastic cell line, MC3T3-E1. Significant chemotactic activity for human monocytes was detected in conditioned medium of the cells at 6 h after initiation of IL-1 beta treatment, and the chemotactic activity increased in both a culture time- and dose-dependent manner. The peak of the chemotactic activity in the conditioned medium was observed in fractions corresponding to a m.w. of 26 kDa when the conditioned medium was fractionated by gel filtration. The chemotactic activity in the peak fraction was completely neutralized by antiserum specific for JE protein. And the JE gene product in the conditioned medium was detected as a microheterogeneous protein with a m.w. of 21 to 33 kDa by immunoprecipitation with the specific antiserum. IL-1 beta induced a maximal JE gene expression in the cells at 3 h after initiation of the cytokine treatment. This significant expression was observed when IL-1 beta was used at a concentration of 10 U/ml, and the expression was dose dependent. The run-on assay showed that the cytokine-induced JE gene expression increased at the transcriptional level. IL-1 beta and TNF-alpha acted synergistically to stimulate JE gene expression in the cells. Expression and product of the JE gene were also observed in an osteoblast-enriched cell population prepared from mouse calvariae. These results suggest the possibility that osteoblastic cells can participate in osteoclast recruitment via the JE gene product.
最近的研究表明，血小板衍生生长因子诱导的JE是一种炎症细胞因子，可引导单核细胞的趋化作用，并且是单核细胞趋化蛋白-1的同源物，后者是一种人类单核细胞趋化因子。单核细胞系细胞在骨组织部位的迁移和聚集对于多核破骨细胞的募集非常重要，因为破骨细胞起源于造血细胞中的单核细胞系细胞。由于白细胞介素-1是骨重塑的有效调节因子，我们研究了白细胞介素-1β是否能在克隆的小鼠成骨细胞系MC3T3-E1中诱导JE表达。在白细胞介素-1β处理开始后6小时，在细胞的条件培养基中检测到对人单核细胞有显著的趋化活性，并且趋化活性呈培养时间和剂量依赖性增加。当通过凝胶过滤对条件培养基进行分级分离时，在对应于分子量为26 kDa的级分中观察到条件培养基中趋化活性的峰值。峰值级分中的趋化活性被针对JE蛋白的特异性抗血清完全中和。通过用特异性抗血清进行免疫沉淀，在条件培养基中检测到JE基因产物是一种分子量为21至33 kDa的微不均一蛋白。白细胞介素-1β在细胞因子处理开始后3小时诱导细胞中JE基因的最大表达。当白细胞介素-1β以10 U/ml的浓度使用时观察到这种显著表达，并且表达呈剂量依赖性。连续分析表明细胞因子诱导的JE基因表达在转录水平上增加。白细胞介素-1β和肿瘤坏死因子-α协同作用以刺激细胞中JE基因的表达。在从小鼠颅骨制备的富含成骨细胞的细胞群体中也观察到JE基因的表达和产物。这些结果提示成骨细胞可能通过JE基因产物参与破骨细胞募集的可能性。
