ALUMINUM-INDUCED MITOGENESIS IN MC3T3-E1 OSTEOBLASTS - POTENTIAL MECHANISM UNDERLYING NEOOSTEOGENESIS
ALUMINUM-INDUCED MITOGENESIS IN MC3T3-E1 OSTEOBLASTS - POTENTIAL MECHANISM UNDERLYING NEOOSTEOGENESIS
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DOI：
10.1210/endo-128-6-3144
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发表时间：
1991-06-01
期刊：
影响因子：
4.8
通讯作者：
DREZNER, MK
中科院分区：
文献类型：
--
作者：
QUARLES, LD;WENSTRUP, RJ;DREZNER, MK
我们最近报道说，给小猎犬注射铝可以刺激骨髓腔中非偶联骨的形成，从而增加骨小梁的体积，并在轴骨内产生新的骨网络。为了研究这种成骨过程是否源于直接刺激骨细胞复制，我们研究了铝对MC3T3-E1克隆细胞系的未分化成骨细胞的有丝分裂作用。在静止成骨细胞的无血清培养基中添加AlCl3 (1-50-mu-M)，导致[H3]胸腺嘧啶并入DNA的量呈剂量依赖性增加，细胞数量也随之增加，达到胎牛血清（FBS）诱导的最大复制率时密度的48%。铝诱导的有丝分裂过程与FBS相似，DNA合成开始于12小时，在48小时的研究期间观察到复制率的逐渐增加。此外，AlCl3和FBS对DNA合成的最大刺激并不是相加的，而铝与低浓度FBS结合时对细胞复制有额外的影响。细胞周期动力学分析表明，与FBS类似，铝通过诱导细胞周期从G0期过渡到S期来影响成骨细胞的复制活性。此外，细胞暴露于铝后30分钟c-fos mRNA快速积累，表明铝与胎牛血清一样，诱导了生长调节基因的表达。甲磺酸去铁胺，一种铝的螯合剂，以剂量依赖性的方式阻断铝的复制作用。相反，百日咳毒素作为某些g蛋白的特异性抑制剂，对铝的有丝分裂作用没有影响，表明铝诱导的有丝分裂发生是通过百日咳毒素不敏感途径发生的。虽然特定的细胞通路仍有待确定，但这些数据提供了初步证据，表明铝诱导的新骨形成可能依赖于直接刺激成骨细胞复制。
We recently reported that aluminum administration to beagles stimulates uncoupled bone formation in the marrow cavity which increases trabecular bone volume and generates new osseous networks within the axial skeleton. To investigate whether this osteogenic process results from direct stimulation of bone cell replication, we examined the mitogenic effects of aluminum on undifferentiated osteoblasts derived from the MC3T3-E1 clonal cell line. Addition of AlCl3 (1-50-mu-M) to serum-free culture medium of quiescent osteoblasts resulted in a dose-dependent increase in [H3] thymidine incorporation into DNA and a concordant increase in cell number to 48% of the density achieved at the maximum replicative rate induced by fetal bovine serum (FBS). The time course of aluminum-induced mitogenesis was similar to that of FBS, with onset of DNA synthesis detectable by 12 h and progressive increases in replicative rates observed over a 48-h study period. Moreover, maximal stimulation of DNA synthesis by AlCl3 and that by FBS were not additive, whereas aluminum exerted additional effects on cell replication when combined with low FBS concentrations. Analysis of cell cycle kinetics indicated that aluminum, analogous to FBS, influences the osteoblast replicative activity by inducing transition from the G0 to the S phase of the cell cycle. In addition, exposure of cells to aluminum resulted in rapid accumulation of c-fos mRNA by 30 min, indicating that aluminum, like fetal bovine serum, induced expression of growth-regulating genes.Deferoxamine mesylate, a chelator of aluminum, blocked the replicative actions of aluminum in a dose-dependent fashion. In contrast, pertussis toxin, a specific inhibitor of certain G-proteins, had no effect on the mitogenic effect of aluminum, indicating that aluminum-induced mitogenesis occurs by a pertussis toxin-insensitive pathway. Though the particular cellular pathway remains to be defined, these data provide initial evidence that aluminum-induced neosteogenesis may depend upon direct stimulation of osteoblast replication.