Huang Yao, Mei Wei, Chen Jian, Jiang Tao, Zhou Zheng, Yin Guoyong, Fan Jin
Department of Orthopaedics, Institute of Sport Medicine, Affiliated Hospital of Nanjing University of TCM, Nanjing, China.
Department of Orthopaedics, Institute of Traumatology Department, Affiliated Hospital of Nanjing University of TCM, Nanjing, China.
J Cell Biochem. 2019 Feb;120(2):1903-1915. doi: 10.1002/jcb.27504. Epub 2018 Oct 26.
In this experiment, the cross-talk betweenNotch and the NF-κB signaling pathway was examined to reveal the mechanism of slowing down the type II collagen (ColII) and aggrecan degeneration affected by inflammatory cytokines. The expression levels of ColII and aggrecan in the intervertebral disc were observed through immunohistochemistry and hematoxylin-eosin staining+alcian blue staining, respectively. The expression levels of ColII, aggrecan, Runx2, and NF-κB in the nuclei of human nucleus pulposus cells (hNPCs) in each group, as well as the phosphorylation and acetylation levels of p65, were examined through Western blot analysis. The 293T cells were transfected with a plasmid containing the overexpressed relative domain of Notch1 intracellular domain (NICD1), and immunoprecipitation (IP) was performed to observe the combination of NICD1 and p65. HNPCs were transfected with a lentiviral-contained overexpression lacking the ANK region of NICD1, and IP was performed to observe the combination of NICD1 and p65. The expression of ColII and aggrecan in the intervertebral disc culture increased when γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-Sphenylglycine t-butyl ester (DAPT) was added to the disc culture medium. Western blot revealed that DAPT inhibited p65 phosphorylation and acetylation, and the p65 and p50 levels in the nucleus decreased. NICD1 was found to be combined with p65 in contrast to the reverse consequences after ANK domain deletion in hNPCs. In nucleus pulposus cells, the combination of p65 and the ANK domain of NICD1 is a critical procedure for the degeneration related to the NF-κB signaling pathway activation induced by IL-1β and TNF-α.
在本实验中,研究了Notch与NF-κB信号通路之间的相互作用,以揭示减缓炎性细胞因子影响的II型胶原蛋白(ColII)和聚集蛋白聚糖退变的机制。分别通过免疫组织化学和苏木精-伊红染色+阿尔辛蓝染色观察椎间盘内ColII和聚集蛋白聚糖的表达水平。通过蛋白质印迹分析检测每组人髓核细胞(hNPCs)细胞核中ColII、聚集蛋白聚糖、Runx2和NF-κB的表达水平,以及p65的磷酸化和乙酰化水平。用含有Notch1细胞内结构域(NICD1)过表达相关结构域的质粒转染293T细胞,并进行免疫沉淀(IP)以观察NICD1与p65的结合情况。用含有缺失NICD1ANK区域的过表达慢病毒转染hNPCs,并进行IP以观察NICD1与p65的结合情况。当向椎间盘培养基中添加γ-分泌酶抑制剂N-[N-(3,5-二氟苯乙酰基)-1-丙氨酰基]-S-苯甘氨酸叔丁酯(DAPT)时,椎间盘培养物中ColII和聚集蛋白聚糖的表达增加。蛋白质印迹显示,DAPT抑制p65磷酸化和乙酰化,细胞核中p65和p50水平降低。与hNPCs中ANK结构域缺失后的相反结果相比,发现NICD1与p65结合。在髓核细胞中,p65与NICD1的ANK结构域结合是IL-1β和TNF-α诱导的与NF-κB信号通路激活相关的退变的关键过程。