Department of Orthopedics, Qilu Hospital of Shandong University, Jinan 250000, Shandong, China.
Department of Orthopedics, Qilu Hospital of Shandong University, Jinan 250000, Shandong, China.
Life Sci. 2019 Jul 1;228:208-214. doi: 10.1016/j.lfs.2019.05.002. Epub 2019 May 2.
Current study aimed to investigate the effects of lncRNA SNHG1 on osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs) and explore the underlying mechanisms.
Mouse model of osteoporosis was created by ovariectomy (OVX). The BMD of mice spine, the serum level of β-CTX and the ALP activity were measured. The expression of SNHG1, JNK, p-JNK, p-38, p-p38 and Osterix were examined by qRT-PCR and Western blot. Co-IP assay was used to verify the effect of SNHG1 on the interaction between p-p38 and Nedd4. Ubiquitination assay was used to evaluate the roles of SNHG1 in ubiquitination of p-p38.
In the mice with osteoporosis, BMD was decreased and β-CTX concentration and SNHG1 expression were increased. ALP activity and p-p38 protein level were elevated and SNHG1 expression was down-regulated in BMSCs stimulated by osteogenic inducer, while the effects were reversed by SNHG1 over-expression. SNHG1 over-expression enhanced the interaction between Nedd4 and p-p38, disrupted protein stability of p-p38, and promoted the ubiquitination of p-p38. In addition, pcDNA-SNHG1 down-regulated p-p38 protein level, and sh-Nedd4 removed the trend. Nedd4 silencing elevated ALP activity and Osterix protein level, while p-38 inhibitor abrogated the effects. In vivo, SNHG1 silence increased BMD and Osterix protein level, and decreased endogenous SNHG1 expression in mice with OVX.
This study proved the regulation mechanism that lncRNA SNHG1 negatively regulates p38 MAPK signal pathway through ubiquitination mediated by Nedd4, and thus inhibits osteogenic differentiation of BMSCs.
本研究旨在探讨 lncRNA SNHG1 对骨髓间充质干细胞（BMSCs）成骨分化的影响，并探讨其潜在机制。
通过卵巢切除术（OVX）建立骨质疏松症小鼠模型。测量小鼠脊柱的 BMD、血清β-CTX 水平和 ALP 活性。通过 qRT-PCR 和 Western blot 检测 SNHG1、JNK、p-JNK、p-38、p-p38 和 Osterix 的表达。使用 co-IP 实验验证 SNHG1 对 p-p38 和 Nedd4 相互作用的影响。使用泛素化实验评估 SNHG1 在 p-p38 泛素化中的作用。
在骨质疏松症小鼠中，BMD 降低，β-CTX 浓度和 SNHG1 表达增加。成骨诱导剂刺激 BMSCs 时，ALP 活性和 p-p38 蛋白水平升高，SNHG1 表达下调，而过表达 SNHG1 则逆转了这些变化。SNHG1 过表达增强了 Nedd4 和 p-p38 之间的相互作用，破坏了 p-p38 蛋白的稳定性，并促进了 p-p38 的泛素化。此外，pcDNA-SNHG1 下调了 p-p38 蛋白水平，而 sh-Nedd4 消除了这种趋势。Nedd4 沉默增加了 ALP 活性和 Osterix 蛋白水平，而 p-38 抑制剂则阻断了这种作用。在体内，沉默 SNHG1 增加了 BMD 和 Osterix 蛋白水平，并降低了 OVX 小鼠内源性 SNHG1 的表达。
本研究证明了 lncRNA SNHG1 通过 Nedd4 介导的泛素化负调控 p38 MAPK 信号通路，从而抑制 BMSCs 的成骨分化。
