Wang Zheng, Fu Changfeng, Chen Yong, Xu Feng, Wang Zhenyu, Qu Zhigang, Liu Yi
Department of Spinal Surgery,The First Hospital of Jilin University, No.71,Xinmin Avenue, Chaoyang District, Changchun, Jilin Province 130021,China.
Department of Neurosurgery, The First Hospital of Jilin University, No.71, Xinmin Avenue, Chaoyang District, Changchun, Jilin Province 130021, China.
PLoS One. 2016 Jan 29;11(1):e0147764. doi: 10.1371/journal.pone.0147764. eCollection 2016.
Bone-morphogenetic protein-7 (BMP-7) is a growth factor that plays a major role in mediating anabolism and anti-catabolism of the intervertebral disc matrix and cell homeostasis. In osteoblasts, Forkhead box protein C2 (FoxC2) is a downstream target of BMPs and promotes cell proliferation and differentiation. However, the role FoxC2 may play in degenerative human intervertebral disc tissue and the relationship between FoxC2 and BMP-7 in nucleus pulposus (NP) cells remain to be elucidated. This study aims to investigate the presence and signaling mechanisms of FoxC2 in degenerative human intervertebral disc tissue and NP cells. Western blot and real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) analyses were used to measure FoxC2 expression in the NP tissue and cells. Transfections were carried out to measure the effect of FoxC2 on BMP-7-mediated extracellular matrix upregulation. Adenoviral knock-down of Smad1 was performed to investigate the mechanism of BMP-7-induced FoxC2 expression. In degenerative NP tissue, FoxC2 was markedly upregulated and positively correlated with increased disc degeneration. Induction of NP cell proliferation was confirmed by using cell counting kit-8 assay, immunocytochemistry and real-time qRT-PCR for Ki67. FoxC2 led to decreased noggin expression and increased Smad1/5/8 phosphorylation. During combined treatment with BMP-7, FoxC2 greatly potentiated anabolism through synergistic mechanisms on ECM formation. Combination therapy using BMP-7 and FoxC2 may be beneficial to the treatment of intervertebral disc degeneration.
骨形态发生蛋白-7（BMP-7）是一种生长因子，在介导椎间盘基质的合成代谢和抗分解代谢以及细胞稳态中起主要作用。在成骨细胞中，叉头框蛋白C2（FoxC2）是骨形态发生蛋白的下游靶点，可促进细胞增殖和分化。然而，FoxC2在人类退变椎间盘组织中可能发挥的作用以及在髓核（NP）细胞中FoxC2与BMP-7之间的关系仍有待阐明。本研究旨在探讨FoxC2在人类退变椎间盘组织和NP细胞中的存在情况及其信号传导机制。采用蛋白质免疫印迹法和实时定量逆转录聚合酶链反应（qRT-PCR）分析来检测NP组织和细胞中FoxC2的表达。进行转染以检测FoxC2对BMP-7介导的细胞外基质上调的影响。通过腺病毒敲低Smad1来研究BMP-7诱导FoxC2表达的机制。在退变的NP组织中，FoxC2明显上调，且与椎间盘退变加重呈正相关。使用细胞计数试剂盒-8检测、免疫细胞化学和针对Ki67的实时qRT-PCR证实了NP细胞增殖的诱导。FoxC2导致头蛋白表达降低，Smad1/5/8磷酸化增加。在与BMP-7联合处理期间，FoxC2通过对细胞外基质形成的协同机制极大地增强了合成代谢。使用BMP-7和FoxC2的联合治疗可能有益于椎间盘退变的治疗。
