Department of Pharmacology, Faculty and Graduate School of Dental Medicine, Hokkaido University, Kita13 Nishi7, Kita-Ku, Sapporo, 060-8586, Japan.
Department of Stomatology, The Fourth Affiliated Hospital of Harbin Medical University, Harbin, 150001, People's Republic of China.
Cell Commun Signal. 2024 Nov 22;22(1):561. doi: 10.1186/s12964-024-01945-8.
Understanding the intricate cellular interactions involved in bone restoration is crucial for developing effective strategies to promote bone healing and mitigate conditions such as osteoporosis and fractures. Here, we provide compelling evidence supporting the anabolic effects of a pharmacological Pyk2 inhibitor (Pyk2-Inh) in promoting bone restoration. In vitro, Pyk2 signaling inhibition markedly enhances alkaline phosphatase (ALP) activity, a hallmark of osteoblast differentiation, through activation of canonical Wnt/β-catenin signaling. Notably, analysis of human mesenchymal stem cells through RNA-seq revealed a novel candidate, SCARA5, identified through Pyk2-Inh treatment. We demonstrate that Scara5 plays a crucial role in suppressing the differentiation from stromal cells into adipocytes, and accelerates lineage commitment to osteoblasts, establishing Scara5 as a negative regulator of bone formation. Additionally, Pyk2 inhibition significantly impedes osteoclast differentiation and bone resorption. In a co-culture system comprising osteoblasts and osteoclasts, Pyk2-Inh effectively suppressed osteoclast differentiation, accompanied by a substantial increase in the transcriptional expression of Tnfrsf11b and Csf1 in osteoblasts, highlighting a dual regulatory role in osteoblast-osteoclast crosstalk. In an ovariectomized mouse model of osteoporosis, oral administration of Pyk2-Inh significantly increased bone mass by simultaneously reducing bone resorption, promoting bone formation and decreasing bone marrow fat. These results suggest Pyk2 as a potential therapeutic target for both adipogenesis and osteogenesis in bone marrow. Our findings underscore the importance of Pyk2 signaling inhibition as a key regulator of bone remodeling, offering promising prospects for the development of novel osteoporosis therapies.
了解骨修复中复杂的细胞相互作用对于开发有效的策略来促进骨愈合以及减轻骨质疏松症和骨折等疾病至关重要。在这里,我们提供了令人信服的证据,支持药理学 Pyk2 抑制剂 (Pyk2-Inh) 在促进骨修复中的合成代谢作用。在体外,Pyk2 信号抑制通过激活经典的 Wnt/β-连环蛋白信号显著增强碱性磷酸酶 (ALP) 活性,ALP 活性是成骨细胞分化的标志。值得注意的是,通过 RNA-seq 对人间充质干细胞进行分析发现了一种新的候选物 SCARA5,它是通过 Pyk2-Inh 处理鉴定的。我们证明 Scara5 在抑制基质细胞向脂肪细胞分化方面起着关键作用,并加速向成骨细胞的谱系承诺,确立 Scara5 作为骨形成的负调节剂。此外,Pyk2 抑制显著阻碍破骨细胞分化和骨吸收。在成骨细胞和破骨细胞组成的共培养系统中,Pyk2-Inh 有效地抑制破骨细胞分化,同时成骨细胞中转录表达 Tnfrsf11b 和 Csf1 显著增加,突出了在成骨细胞-破骨细胞串扰中的双重调节作用。在去卵巢骨质疏松症小鼠模型中,Pyk2-Inh 的口服给药通过同时减少骨吸收、促进骨形成和减少骨髓脂肪来显著增加骨量。这些结果表明 Pyk2 是骨髓中脂肪生成和成骨的潜在治疗靶点。我们的研究结果强调了抑制 Pyk2 信号作为骨重塑关键调节剂的重要性,为开发新的骨质疏松症治疗方法提供了有希望的前景。