Expression and function of TNF-family proteins and receptors in human osteoblasts
Expression and function of TNF-family proteins and receptors in human osteoblasts
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DOI：
10.1016/j.bone.2003.07.006
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发表时间：
2003-11-01
期刊：
影响因子：
4.1
通讯作者：
Blair, HC
中科院分区：
文献类型：
--
作者：
Bu, RF;Borysenko, CW;Blair, HC
我们研究了肿瘤坏死因子（TNF）家族蛋白如何与成骨细胞相互作用，以解决几个有争议的问题。我们测量的表达TNF，TNF受体，和非信号（诱饵）TNF受体在人成骨细胞来源于间充质干细胞和MG 63人骨肉瘤细胞使用未扩增的mRNA筛选，二次Western或PCR分析，如有指示，并研究了肿瘤坏死因子对成骨细胞在细胞培养的影响。TNF及其受体在MG 63细胞和成骨细胞中的表达相似。表达TNF-R1（p55）、TRAIL受体1和2（DR 4和5）以及Fas;未检测到RANK。TNF家族配体RANKL、TRAIL和TNF α表达，但mRNA相对于受体通常处于低水平，表明成骨细胞TNF信号（包括RANKL）需要特定刺激。MG 63细胞的流式细胞术证实了TNF α受体，并鉴定了具有高表面结合TNF α的亚群。表达的诱饵受体包括一种新的可溶性形式的TNFRSF 25（以前称为DR 3或Apo 3），涉及类风湿性关节炎联系研究，以及骨保护素，一种结合TRAIL和RANKL的良好特征的成骨细胞蛋白，以及结合TRAIL的DcR 2。用末端脱氧核苷酸转移酶标记和膜联蛋白V结合研究成骨细胞凋亡。MG 63细胞对外源性TNF α诱导的凋亡有抵抗力，除非生长在促进成骨细胞样生长或基质结节的培养基中。然而，在支持成骨细胞样表型的培养基中，抗Fas或TNF诱导细胞凋亡，与其他人成骨细胞研究相反。TRAIL引起细胞收缩，支持细胞分化中的功能性TRAIL应答，但不引起细胞凋亡。我们的结论是，人成骨细胞有功能受体的FasL，TNF α，TRAIL，但不是RANKL，成骨细胞的保护，由多种非信号TNF受体对破坏的TNF家族蛋白的条件下，有利于细胞生长。(C)2003年爱思唯尔公司All rights reserved.
We studied how tumor necrosis-factor (TNF)-family proteins interact with osteoblasts to resolve several controversial points. We measured expression of TNFs, TNF-receptors, and nonsignaling (decoy) TNF receptors in human ostcoblasts derived from mesenchymal stem cells and in MG63 human osteosarcoma cells using unamplified mRNA screening, with secondary Western or PCR analysis where indicated, and studied the effects of TNFs on osteoblasts in cell culture. Expression of TNFs and receptors was similar in MG63 cells and osteoblasts. TNF-R1 (p55), TRAIL receptor 1 and 2 (DR4 and 5), and Fas were expressed; RANK was undetectable. TNF-family ligands RANKL, TRAIL, and TNFalpha were expressed, but mRNAs were typically at low levels relative to receptors, suggesting that osteoblastic TNF signals, including RANKL, require specific stimuli. Flow cytometry of MG63 cells confirmed TNFalpha receptors and identified subpopulations with high surface-bound TNFalpha. Decoy receptors expressed included a novel soluble form of TNFRSF25 (formerly DR3 or Apo3), implicated in rheumatoid-arthritis linkage studies, as well as osteoprotegerin, a well-characterized osteoblast protein that binds TRAIL and RANKL, and DcR2, which binds TRAIL. Osteoblast apoptosis was studied using terminal deoxynucleotidyl transferase labeling and annexin V binding. MG63 cells were resistant to apoptosis by exogenous TNFalpha except when grown in media promoting osteoblast-like growth or matrix nodules. However, in media supporting osteoblast-like phenotype, apoptosis was induced by anti-Fas or TNF, in contrast to other studies with human osteoblasts. TRAIL caused cell retraction, supporting functional TRAIL response in cell differentiation, but did not cause apoptosis. We conclude that human osteoblasts have functional receptors for FasL, TNFalpha, TRAIL, but not RANKL, and that osteoblasts are protected by multiple nonsignaling TNF receptors against destruction by TNF-family proteins under conditions favoring cell growth. (C) 2003 Elsevier Inc. All rights reserved.