Tao Ke, Xiao Deming, Weng Jian, Xiong Ao, Kang Bin, Zeng Hui
Department of Orthopaedics, Peking University Shenzhen Hospital, Shenzhen 518036, PR China.
Department of Orthopaedics, Peking University Shenzhen Hospital, Shenzhen 518036, PR China.
Toxicol Lett. 2016 Jan 5;240(1):68-80. doi: 10.1016/j.toxlet.2015.10.007. Epub 2015 Oct 22.
Berberine (BBR) has recently been reported to be extensively used for musculoskeletal disorders such as osteoporosis through enhancing osteogenic differentiation, inhibiting osteoclastogenesis and bone resorption and repressing adipogenesis. Although canonical Wnt signaling plays a crucial role in suppressing bone marrow-derived mesenchymal stem cells (MSCs) commitment to the chondrogenic and adipogenic lineage and enhancing osteogenic differentiation, no previous reports have shown an association between BBR-induced osteogenesis and Wnt/β-catenin signaling pathway. In this study, we aimed to investigate the stimulatory effect and the mechanism of BBR on osteogenic differentiation of human bone marrow-derived MSCs. MSCs were isolated from bone marrow specimens and treated with different concentration of BBR. Cell viability was measured by the WST-8 assay. Effects of BBR on osteogenic differentiation of MSCs were assessed by von Kossa staining, ALP staining and ALP activity. Osteogenic specific genes, chondrogenic and adipogenic related marker genes were determined by quantitative real-time polymerase chain reaction analysis. Western blot and Immunofluorescence staining were performed to analyze OCN and OPN, and β-catenin expression in the presence or absence of BBR combined with DKK-1 or β-catenin siRNA transfection. Increasing concentration of BBR (3, 10 and 30 μM) promoted osteogenic differentiation and osteogenic genes expression after incubation for various days compared with DMSO group, whereas expression levels of chondrogenic and adipogenic related marker genes were dramatically suppressed. After treated with 10μM BBR for 7 days, β-catenin, OPN and OCN expression were significantly induced, which could be effectively suppressed by the addition of DKK-1 or β-catenin siRNA β-catenin. Interestingly, the expression level of Runx2 gene was also decreased by inhibiting the transduction of Wnt/β-catenin signaling. These findings suggest that BBR can stimulate osteogenic differentiation of MSCs not only by enhancing Runx2 expression but also by activating canonical Wnt/β-catenin signaling pathway, and canonical Wnt/β-catenin signaling pathway is in part responsible for BBR-induced osteogenic differentiation of MSCs in vitro. BBR is a potential pharmaceutical medicine by enhancing osteogenic differentiation for bone disorders, such as osteoporosis.
黄连素(BBR)最近被报道可广泛用于治疗肌肉骨骼疾病,如骨质疏松症,其作用机制包括增强成骨分化、抑制破骨细胞生成和骨吸收以及抑制脂肪生成。虽然经典Wnt信号通路在抑制骨髓间充质干细胞(MSCs)向软骨生成和脂肪生成谱系分化以及增强成骨分化方面起着关键作用,但此前尚无报道表明BBR诱导的成骨与Wnt/β-连环蛋白信号通路之间存在关联。在本研究中,我们旨在探讨BBR对人骨髓来源MSCs成骨分化的刺激作用及其机制。从骨髓标本中分离出MSCs,并用不同浓度的BBR进行处理。通过WST-8法检测细胞活力。通过冯科萨染色、碱性磷酸酶(ALP)染色和ALP活性评估BBR对MSCs成骨分化的影响。通过定量实时聚合酶链反应分析确定成骨特异性基因、软骨生成和脂肪生成相关标记基因。进行蛋白质免疫印迹和免疫荧光染色,以分析在存在或不存在BBR并联合DKK-1或β-连环蛋白小干扰RNA(siRNA)转染的情况下骨钙素(OCN)、骨桥蛋白(OPN)和β-连环蛋白的表达。与二甲基亚砜(DMSO)组相比,不同浓度的BBR(3、10和30μM)在孵育不同天数后促进了成骨分化和成骨基因表达,而软骨生成和脂肪生成相关标记基因的表达水平则显著受到抑制。用10μM BBR处理7天后,β-连环蛋白、OPN和OCN的表达明显诱导,添加DKK-1或β-连环蛋白siRNA可有效抑制β-连环蛋白的表达。有趣的是,通过抑制Wnt/β-连环蛋白信号转导,Runx2基因的表达水平也降低了。这些发现表明,BBR不仅可以通过增强Runx2表达来刺激MSCs的成骨分化,还可以通过激活经典Wnt/β-连环蛋白信号通路来实现,并且经典Wnt/β-连环蛋白信号通路在一定程度上负责BBR诱导的体外MSCs成骨分化。BBR通过增强成骨分化,是治疗骨质疏松等骨疾病的一种潜在药物。