Inhibition of RhoA/MRTF-A signaling alleviates nucleus pulposus fibrosis induced by mechanical stress overload
Inhibition of RhoA/MRTF-A signaling alleviates nucleus pulposus fibrosis induced by mechanical stress overload
复制标题
抑制 RhoA/MRTF-A 信号传导可减轻机械应力过载引起的髓核纤维化
DOI：
10.1080/03008207.2021.1952193
复制
发表时间：
2021-08-22
影响因子：
2.9
通讯作者：
Ma, Xuexiao
中科院分区：
文献类型：
--
作者：
Song, Mengxiong;Zhang, Yiran;Ma, Xuexiao
目的/目的：椎间盘退变（IDD）是腰痛的主要原因，临床上治疗IDD的药物缺乏。机械应力超载诱导的纤维化在IDD中起关键作用。已知RhoA/MRTF-A信号可调节组织纤维化；然而，RhoA/MRTF-A对IDD发展的影响尚不清楚。材料与方法：采用免疫组化染色法检测IDD患者和对照组髓核（NP）样品中聚集蛋白、I型胶原、II型胶原、MMP-12、CTGF、MRTF-A的表达。分离培养初代髓核细胞（NPCs），建立加CCG-1423或不加CCG-1423的过载应变模型。western blotting和免疫荧光法检测RhoA、ROCK2、MRTF-A、CTGF、MMP-12蛋白及纤维化相关蛋白水平。结果：IDD样品中I型胶原、MMP-12、CTGF显著上调，聚集蛋白和II型胶原显著下调。MRTF-A的细胞定位与椎间盘退变有关。超载应变增强了MRTF-A的核易位，使NPC形态由纺锤形变为长条状。另外实验显示RhoA、ROCK2、MRTF-A、SRF、MMP-12、CTGF上调；而在超载应变下，npc中聚集蛋白和II型胶原蛋白表达下调。CCG-1423， RhoA/MRTF-A途径抑制剂，逆转菌株诱导的纤维化。结论：机械应力激活RhoA/MRTF-A信号，促进NP细胞外基质（ECM）变性，这与IDD的发生有关。我们的研究结果表明，RhoA/MRTF-A抑制剂CCG-1423可以减轻过度应激引起的NPC变性，并有可能作为IDD的治疗药物。
Purpose/Aim : Intervertebral disc degeneration (IDD) is the leading cause of lower back pain, and clinically useful drugs for IDD are unavailable. Mechanical stress overload-induced fibrosis plays a critical role in IDD. RhoA/MRTF-A signaling is known to regulate tissue fibrosis; however, the effect of RhoA/MRTF-A on the development of IDD is unclear. Materials and methods : The expression of aggrecan, collagen I, collagen II, MMP-12, CTGF, and MRTF-A in nucleus pulposus (NP) samples from IDD patients and controls was detected by immunohistochemical staining. Primary nucleus pulposus cells (NPCs) were isolated and cultured to establish an overload strain model treated with or without CCG-1423. The protein levels of RhoA, ROCK2, MRTF-A, CTGF, and MMP-12 as well as fibrosis-associated proteins were detected by western blotting and immunofluorescence. Results : Collagen I, MMP-12, and CTGF were significantly upregulated, and aggrecan and collagen II were significantly downregulated in the IDD samples. The cellular localization of MRTF-A was associated with intervertebral disc (IVD) degeneration. Overloaded strain enhanced the nuclear translocation of MRTF-A and changed the NPC morphology from spindle-shaped to long strips. Additional experiments showed that RhoA, ROCK2, MRTF-A, SRF, MMP-12, and CTGF were upregulated; however, aggrecan and collagen II were downregulated in NPCs under overload strain. CCG-1423, a RhoA/MRTF-A pathway inhibitor, reversed strain-induced fibrosis. Conclusion : Mechanical stress activates RhoA/MRTF-A signaling to promote extracellular matrix (ECM) degeneration in the NP, which is associated with the development of IDD. Our findings suggest that the RhoA/MRTF-A inhibitor CCG-1423 can alleviate NPC degeneration caused by overload stress and has potential as a therapeutic agent for IDD.