Cyclooxygenase-2 gene disruption promotes proliferation of murine calvarial osteoblasts in vitro.
Cyclooxygenase-2 gene disruption promotes proliferation of murine calvarial osteoblasts in vitro.
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DOI：
10.1016/j.bone.2007.03.009
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发表时间：
2007-07
期刊：
影响因子：
4.1
通讯作者：
Zheng Xu;S. Choudhary;Y. Okada;O. Voznesensky;C. Alander;L. Raisz;C. Pilbeam
中科院分区：
文献类型：
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作者：
Zheng Xu;S. Choudhary;Y. Okada;O. Voznesensky;C. Alander;L. Raisz;C. Pilbeam
环加氧酶-2（COX-2）在成骨细胞中高表达，COX-2产生的前列腺素（PGs）可以增加体外成骨细胞的分化。本研究的目的是检查COX-2表达对颅骨成骨细胞增殖和凋亡的影响。原代成骨细胞 (POB) 从 COX-2 野生型 (WT) 和基因敲除 (KO) 小鼠的颅骨中培养。通过3 H-胸苷掺入评估POB增殖并通过流式细胞术分析细胞复制和细胞周期分布。 POB 细胞凋亡通过流式细胞仪上的膜联蛋白和 PI 染色进行评估。正如预期的那样，与 KO 培养物相比，WT 培养物中的 PGE2 产量和碱性磷酸酶 (ALP) 活性有所增加。相反，在培养第 4 天时，与 KO 细胞相比，WT 细胞的细胞数量有所减少。在培养第 3-7 天测量的增殖能力，KO 中的增殖比 WT POB 中的增殖高 2 倍，并且与 Go/G1 减少和 S 细胞周期分布增加相关。基础培养条件下培养第5天COX-2基因型对细胞凋亡无显着影响。通过添加 PGE2 或蛋白激酶 A 激动剂，KO POB 中的细胞生长会减少，而通过添加选择性 COX-2 抑制剂 NS398 可以增加 WT POB 中的细胞生长。相比之下，分别通过ALP和结晶紫染色评估的骨髓基质细胞(MSC)培养物中的分化和细胞生长，与来自KO小鼠的MSC相比，来自WT小鼠的MSC增加，并且外源性PGE2增加了KO MSC培养物中的细胞生长。我们得出的结论是，继发于COX-2表达的PGs降低了培养的颅盖细胞中的成骨细胞增殖，但增加了MSC培养物中的成骨细胞前体细胞的生长。
Cyclooxygenase-2 (COX-2) is highly expressed in osteoblasts, and COX-2 produced prostaglandins (PGs) can increase osteoblastic differentiation in vitro. The goal of this study was to examine effects of COX-2 expression on calvarial osteoblastic proliferation and apoptosis. Primary osteoblasts (POBs) were cultured from calvariae of COX-2 wild-type (WT) and knockout (KO) mice. POB proliferation was evaluated by3H-thymidine incorporation and analysis of cell replication and cell cycle distribution by flow cytometry. POB apoptosis was evaluated by annexin and PI staining on flow cytometry. As expected, PGE2production and alkaline phosphatase (ALP) activity were increased in WT cultures compared to KO cultures. In contrast, cell numbers were decreased in WT compared to KO cells by day 4 of culture. Proliferation, measured on days 3–7 of culture, was 2-fold greater in KO than in WT POBs and associated with decreased Go/G1 and increased S cell cycle distribution. There was no significant effect of COX-2 genotype on apoptosis under basal culture conditions on day 5 of culture. Cell growth was decreased in KO POBs by the addition of PGE2or a protein kinase A agonist and increased in WT POBs by the addition of NS398, a selective COX-2 inhibitor. In contrast, differentiation and cell growth in marrow stromal cell (MSC) cultures, evaluated by ALP and crystal violet staining respectively, were increased in MSCs from WT mice compared to MSCs from KO mice, and exogenous PGE2increased cell growth in KO MSC cultures. We conclude that PGs secondary to COX-2 expression decrease osteoblastic proliferation in cultured calvarial cells but increase growth of osteoblastic precursors in MSC cultures.