Biver Galadrielle, Wang Ning, Gartland Alison, Orriss Isabel, Arnett Timothy R, Boeynaems Jean-Marie, Robaye Bernard
Institute of Interdisciplinary Research, Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, Gosselies, Belgium.
Stem Cells. 2013 Dec;31(12):2747-58. doi: 10.1002/stem.1411.
Accumulating evidence indicates that extracellular nucleotides, signaling through purinergic receptors, play a significant role in bone remodeling. Mesenchymal stem cells (MSCs) express functional P2Y receptors whose expression level is regulated during osteoblast or adipocyte differentiation. P2Y13 -deficient mice were previously shown to exhibit a decreased bone turnover associated with a reduction in the number of both osteoblasts and osteoclasts on the bone surfaces. We therefore examined whether P2Y13 R activation was involved in the osteogenic differentiation of MSC. Our study demonstrated that ADP stimulation of P2Y13 R(+/+) (but not P2Y13 R(-/-) ) adherent bone marrow stromal cells (BMSCs) increased significantly the formation of alkaline phosphatase-colony-forming units (CFU-ALP) as well as the expression of osteoblastic markers (osterix, alkaline phosphatase, and collagen I) involved in the maturation of preosteoblasts into osteoblasts. The number of CFU-ALP obtained from P2Y13 R(-/-) BMSC and the level of osteoblastic gene expression after osteogenic stimulation were strongly reduced compared to those obtained in wild-type cell cultures. In contrast, when P2Y13 R(-/-) BMSCs were incubated in an adipogenic medium, the number of adipocytes generated and the level of adipogenic gene expression (PPARγ2 and Adipsin) were higher than those obtained in P2Y13 R(+/+) MSC. Interestingly, we observed a significant increase of the number of bone marrow adipocytes in tibia of P2Y13 R(-/-) mice. In conclusion, our findings indicate that the P2Y13 R plays an important role in the balance of osteoblast and adipocyte terminal differentiation of bone marrow progenitors. Therefore, the P2Y13 receptor can be considered as a new pharmacological target for the treatment of bone diseases like osteoporosis. STEM Cells 2013;31:2747-2758.
越来越多的证据表明，细胞外核苷酸通过嘌呤能受体进行信号传导，在骨重塑中发挥重要作用。间充质干细胞（MSC）表达功能性P2Y受体，其表达水平在成骨细胞或脂肪细胞分化过程中受到调节。先前研究表明，P2Y13基因缺陷小鼠的骨转换率降低，同时骨表面的成骨细胞和破骨细胞数量减少。因此，我们研究了P2Y13R激活是否参与了MSC的成骨分化。我们的研究表明，ADP刺激P2Y13R(+/+)（而非P2Y13R(-/-)）贴壁骨髓基质细胞（BMSC）可显著增加碱性磷酸酶集落形成单位（CFU-ALP）的形成，以及参与前成骨细胞成熟为成骨细胞的成骨细胞标志物（osterix、碱性磷酸酶和I型胶原）的表达。与野生型细胞培养物相比，从P2Y13R(-/-)BMSC获得的CFU-ALP数量以及成骨刺激后的成骨细胞基因表达水平显著降低。相反，当P2Y13R(-/-)BMSC在脂肪生成培养基中培养时，产生的脂肪细胞数量和脂肪生成基因表达水平（PPARγ2和脂肪酶）高于P2Y13R(+/+)MSC。有趣的是，我们观察到P2Y13R(-/-)小鼠胫骨中的骨髓脂肪细胞数量显著增加。总之，我们的研究结果表明，P2Y13R在骨髓祖细胞成骨细胞和脂肪细胞终末分化的平衡中起重要作用。因此，P2Y13受体可被视为治疗骨质疏松症等骨疾病的新药物靶点。《干细胞》2013年；31卷：2747 - 2758页
