Department of Orthopaedics, Medical Center of Hip, Luoyang Orthopedic-Traumatological Hospital (Orthopedics Hospital of Henan Province), No.82, Qiming South Road, Fuhe District, Luoyang, 471002, Henan, People's Republic of China.
Postdoctoral Mobile Station, Guangzhou University of Traditional Chinese Medicine, Guangzhou, 510405, Guangdong, People's Republic of China.
Hum Cell. 2022 Jan;35(1):133-149. doi: 10.1007/s13577-021-00629-6. Epub 2021 Oct 11.
Fracture healing is a complex event with the involvement of many cell systems, cytokines, as well as mRNAs. Herein, we report the interactions among long noncoding RNA X-inactive specific transcript (XIST)/microRNA-135 (miR-135)/cAMP response element-binding protein 1 (CREB1) axis during fracture healing. We observed increased expression of XIST in patients with long-term unhealed fracture by microarray analysis. Subsequently, a mouse model with tibial fracture and a cell model using osteoblast-like MC3T3-E1 cells were generated. The XIST overexpression during fracture healing decreased proliferation and differentiation of MC3T3-E1 cells, while silencing of XIST facilitated MC3T3-E1 cell growth. Furthermore, miR-135 targeted CREB1 and negatively regulated its expression. XIST acted as a sponge for miR-135, thereby upregulating CREB1 and promoting the activity of the TNF-α/RANKL pathway. Transfection of miR-135 inhibitor or CREB1 overexpression blocked the stimulating effects of XIST knockdown on MC3T3-E1 cell growth. Besides, specific inhibitors of the TNF-α/RANKL pathway reversed the repressive role of XIST in cell osteogenic differentiation. All in all, these findings suggest that XIST knockdown induces the differentiation of osteoblast-like cells via regulation of the miR-135/CREB1/TNF-α/RANKL axis. XIST, as a consequence, represents an attractive therapeutic strategy to accelerate fracture healing.
骨折愈合是一个涉及多种细胞系统、细胞因子和 mRNAs 的复杂事件。在此,我们报告了长非编码 RNA X 失活特异性转录物(XIST)/微小 RNA-135(miR-135)/环腺苷酸反应元件结合蛋白 1(CREB1)轴在骨折愈合过程中的相互作用。通过微阵列分析,我们观察到长期未愈合骨折患者 XIST 的表达增加。随后,建立了胫骨骨折的小鼠模型和成骨样 MC3T3-E1 细胞的细胞模型。骨折愈合过程中 XIST 的过表达降低了 MC3T3-E1 细胞的增殖和分化,而 XIST 的沉默促进了 MC3T3-E1 细胞的生长。此外,miR-135 靶向 CREB1 并负调控其表达。XIST 作为 miR-135 的海绵,上调 CREB1 并促进 TNF-α/RANKL 通路的活性。miR-135 抑制剂的转染或 CREB1 的过表达阻断了 XIST 敲低对 MC3T3-E1 细胞生长的刺激作用。此外,TNF-α/RANKL 通路的特异性抑制剂逆转了 XIST 对细胞成骨分化的抑制作用。总之,这些发现表明 XIST 敲低通过调节 miR-135/CREB1/TNF-α/RANKL 轴诱导成骨样细胞的分化。因此,XIST 可作为加速骨折愈合的有吸引力的治疗策略。