Effects of interleukin-1, tumor necrosis factor-β, and forskolin on tissue plasminogen activator activity in human osteoblastic osteosarcoma cells

Summary The effects of interleukin-1 (IL-1), forskolin, and tumor necrosis factor (TNF-) on tissue plasminogen activator (t-PA) activity were studied in the human osteoblastic osteosarcoma cell line, G292. t-PA activity was measured in the cell media using the chromogenic substrate, S-2251. After a 24 hour incubation period, IL-1 increased t-PA in a dose-dependent manner. The effect of IL-1 at 10.0 U/ml was partially inhibited in the presence of indomethacin. Forskolin (1.0 M) increased t-PA activity after 24 hours with the effects of combined treatment of IL-1 (1.0 U/ml, 10.0 U/ml) and forskolin being apparently additive in nature. TNF- (10^-8–10^-7 M) also produced increased t-PA activity in the cell medial after a 24 hour incubation period. These results suggest that the cytokines, IL-1 and TNF-, can increase t-PA activity in G292 cells and that there is both a cAMP-dependent as well as a cAMP-independent pathway involved in the regulation of this osteoblastic cell function.     

The Effect of Carboxyl-Terminal Propeptide of Type I Collagen (c-Propeptide) on Collagen Synthesis of Preosteoblasts and Osteoblasts

Recently we found that the carboxyl-terminal propeptide of type I collagen (c-propeptide) is a major secretory protein of osteoblasts. Mature osteoblasts secreted 64 nM c-propeptide, and it was reported that 40 nM c-propeptide inhibited collagen synthesis at 80% of the control level. In this study, we investigated the effect of c-propeptide on collagen synthesis of preosteoblasts and osteoblasts, and found that preosteoblasts downregulated collagen synthesis by 40 nM c-propeptide, but osteoblasts were not affected by the same condition. When the binding activities of c-propeptide for preosteoblasts and osteoblasts were compared, osteoblasts showed weak affinity to c-propeptide compared with preosteoblasts, and the number of receptors for c-propeptide decreased in osteoblasts. These results imply that a decrease of receptors in osteoblasts might reduce the sensitivity of osteoblasts to c-propeptide. Received: 6 August 1999 / Accepted: 9 May 2000 / Online publication: 22 September 2000     

孕酮对离体胎鼠头盖骨成骨细胞增殖与分化的影响

目的：从细胞、基因水平探讨孕酮对成骨细胞增殖及分化的影响。方法：胎鼠头盖骨成骨细胞在体外经不同浓度（１０－９ｍｏｌ／Ｌ～１０－６ｍｏｌ／Ｌ）的孕酮作用后，对其细胞增殖、碱性磷酸酶（ＡＬＰ）活性、骨钙素ｍＲＮＡ表达、骨钙素分泌及骨小结形成进行检测分析。结果：（１）孕酮对成骨细胞增殖无明显促进作用；（２）孕酮增加细胞ＡＬＰ活性；（３）孕酮提高骨钙素ｍＲＮＡ表达及骨钙素的分泌，孕酮对骨钙素基因表达的刺激作用呈剂量依赖性；（４）孕酮增加骨小结形成的数量及面积。结论：孕酮对离体胎鼠头盖骨成骨细胞的分化具有多重促进效果，但对细胞的增殖无影响。     

健骨二仙丸介导间充质干细胞的成骨细胞定向诱导及其成骨活性

目的:研究健骨二仙丸对间充质干细胞(Mesenchymal Stem Cells,MSCs)成骨细胞定向分化及其成骨活牲的影响.方法:采用标准Ficoll-Hypaque技术分离人脐血MSCs,以地塞米松、β-磷酸甘油和维生素C为辅剂定向诱导成骨细胞,碱性磷酸酶、骨矿化结节、骨钙素及上清钙含量与Ⅰ型胶原作为成骨细胞鉴定与活性评价的指标.另以健骨二仙丸或健骨二仙丸合地寒米松、β-磷酸甘油与维生素C为辅剂诱导,用正常培养液作为空白对照,15 d后观测对比上述相关指标.结果:健骨二仙丸不能单独诱导MSCs向成骨细胞转化,对MSCs成骨细胞诱导前后的细胞形态无任何影响.定向成骨细胞诱导后,健骨二仙丸能显著提高其标志性产物碱性磷酸酶、骨矿化结节和上清钙、骨钙素以及Ⅰ型胶原的表达.结论:健骨二仙丸作为补肾益气药能促进MSCs成骨细胞定向转化,提高其成骨活性.     

rhBMP_2不同动物异位诱导成骨及其小鼠体内诱导成骨的剂量依赖性

目的对大肠杆菌表达的hBMP2在小鼠体内进行剂量依赖性研究,并观察其在大鼠和家兔体内异位诱导成骨情况,为临床应用提供参考。方法大鼠、家兔股部肌袋植入rhBMP21.5和3.0mg,植入后1、2、4周取材观察成骨情况;小鼠股部肌袋植入100~1000μg的rhBMP2,植入后1、2、3周取材,行组织学检查,成骨量分析,碱性磷酸酶和钙含量测定。结果大鼠植入1.5mgrhBMP2植入2周、家兔3.0mgrhBMP2植入4周表现为高效成骨活性。rhBMP2小鼠体内诱导成骨实验表现为成骨量,碱性磷酸酶活性和钙含量显著的剂量依赖性。结论原核表达的hBMP在小鼠、大鼠和家兔体内有高效的诱导成骨活性,小鼠体内实验rhBMP2表现为明显的剂量依赖性。     

丹参对大鼠成骨细胞增殖和分化的影响

目的：了解丹参对SD大鼠成骨细胞增殖和分化的影响。方法：取新生的SD大鼠头盖骨，胶原酶法培养成骨细胞，用MTT法来测定不同浓度丹参对体外培养成骨细胞在24、48、72h不同时段的促细胞增殖作用；采用碱性磷酸（ALP）活性观察上述药物的促细胞分化作用。结果：0．05％、0．10％、0．15％的丹参可促进成骨细胞增殖率提高（P〈0．05）；不同浓度丹参可使碱性磷酸酶（ALP）活性增强（P〈0．05）。结论：丹参具有促进成骨细胞增殖及分化的作用。     

成骨细胞中NO及c-fos对流体剪切力的响应

目的：研究NO及c—fos对不同流体剪切力作用时间的生理响应。方法：分离新生SD大鼠颅盖骨中的成骨细胞并分成三组，分别使用含10％FBS、0．3mmol／L L—NMMA和0．1mmol／L SNP的DMEM培养液预处理24h，加载大小为1．2Pa的剪切力。每组在加载剪切力0min、10min、15min、30min、60min后分别测试c—fos mRNA、NOS的表达。结果：c—fos mRNA表达在水平剪切力加载15min时明显增高（P〈0．05），在使用L—NMMA后明显降低（P〈0．05），而使用SNP后明显升高（P〈0．05）。结论：c—fos和NO参与了力学刺激引发细胞响应的过程，特别是在外界信号刺激引起的信息传递级联反应中起重要的偶联作用。     

Identification of Genes Differentially Expressed in Cultured Human Osteoblasts Versus Human Fibroblasts by DNA Microarray Analysis

Little is known about patterns of gene expression from cells populating the connective tissues. This study investigated the possible variance of gene expression profile between human osteoblasts (HO) and human fibroblasts (HF) in vitro, using DNA microarray technology. Clustering identification was used to compare expression patterns between HO and HF for biological significance. Our results showed that genes encoding the extracellular matrix or apoptosis-related proteins tended to be expressed in greater abundance in HO, while more proteolysis-related proteins were expressed in higher level in HF. Significant differences in expression were also noted with genes related to signaling pathways. To confirm the array results, three genes (periostin, MFG-E8, MMP-10) were selected and analyzed independently by RT-PCR and northern blot. The results were found consistent with the array data in HO and HF. The present findings suggest that HO and HF differ not only phenotypically but in the expression level of tissue specific genes to assure the turnover and homeostasis of their respective tissues.     

Crosstalk Between Mucosal Inflammation and Bone Metabolism in Chronic Rhinosinusitis

Chronic rhinosinusitis (CRS) is a multifactorial and highly heterogeneous upper airway disease that affects approximately 12% of the general population. There is increasing evidence supporting the impact of osteitis on the pathophysiology of CRS. Osteitis is frequently observed in patients with CRS, and is associated with severe sinonasal inflammation and recalcitrant cases. The overlying inflammatory sinonasal mucosa plays a critical role in the initiation of osteitis; however, the underlying molecular mechanisms and functional significance remain unclear. Increasingly many studies have suggested that immune cells play a crucial role in the bone remodeling process in CRS. The purpose of this review is to summarize the current state of knowledge regarding the specific role of sinonasal inflammation in bone remodeling in CRS patients.     

脂多糖诱导成骨细胞增殖的Notch信号通路研究

目的:探讨脂多糖(LPS)对成骨细胞增殖的Notch信号通路的诱导激活作用.方法:以MC3T3-E1细胞为模型,设计正常对照组、LPS浓度梯度组(5、10μg组)、DAPT组(先加入DAPT,随后加入10μg LPS)和DMSO组(先加入DMSO,随后加入10μg LPS).分别于OBDM培养基中诱导分化5d和15d时加入不同浓度的脂多糖、DAPT和DMSO,培养3d后进行MTT实验,随后采用PCR检测各组细胞中HES1mRNA表达量.结果:与对照组相比,加入脂多糖5μg组第5天,脂多糖10 μg组第5、6、7天时细胞吸光度显著降低(P＜0.01);与正常对照组相比,5μg组和10 μg组脂多糖均能够使MC3T3-E1细胞和成骨细胞前体细胞增殖能力降低(P＜0.01),而仅5μg组LPS能够使成骨细胞增殖分化能力降低(P＜0.01);不同浓度LPS均能够诱导HES1mRNA的表达,与对照组相比,差异有统计学意义(P＜0.01);随着LPS浓度增加,HES1mRNA表达量显著增加(P＜0.01);与对照组相比,DM-SO组HES1mRNA量显著较高,差异具有统计学差异(P＜0.05).结论:脂多糖抑制骨头发育和愈合,可能是通过激活经典的Notch信号通路,诱导HES1mRNA的表达,抑制成骨细胞及其前体细胞的增殖分化造成.