食品科学 ›› 2017, Vol. 38 ›› Issue (17): 26-31.doi: 10.7506/spkx1002-6630-201717005

• 基础研究 • 上一篇    下一篇

乳源酪蛋白糖巨肽对NF-κB信号通路中关键蛋白的调控作用

王 泳,龚建苗,贾 彦,赵 培,庞广昌,阎亚丽*,陈庆森*   

  1. 天津市食品生物技术重点实验室,天津商业大学生物技术与食品科学学院,天津 300134
  • 出版日期:2017-09-15 发布日期:2017-09-12
  • 基金资助:
    国家自然科学基金面上项目(31071522)

Regulatory Effect of Milk-Derived Casein Glycomacropeptide on Key Enzymes Involved in NF-κB Signaling Pathway

WANG Yong, GONG Jianmiao, JIA Yan, ZHAO Pei, PANG Guangchang, YAN Yali*, CHEN Qingsen*   

  1. Tianjin Key Laboratory of Food Biotechnology, College of Biotechnology and Food Science,Tianjin University of Commerce, Tianjin 300134, China
  • Online:2017-09-15 Published:2017-09-12

摘要: 以结肠癌细胞HT-29为细胞系,在确定乳源性酪蛋白糖巨肽(casein glycomacropeptide,CGMP)对脂多糖(lipopolysaccharides,LPS)诱导的HT-29细胞核因子-κB(nuclear factor-κB,NF-κB)亚单位p65蛋白影响的基础上,在最适作用时间条件下,利用Western blotting技术进一步检测乳源CGMP对NF-κB信号通路上关键蛋白IκBα、p-IκBα、E3RSIκB、UBC5表达水平的影响,以阐述乳源CGMP调控NF-κB信号通路中关键蛋白的作用机制。结果表明:乳源CGMP组的3 种质量浓度(0.001、0.010、0.100 μg/mL)均可在一定程度上抑制LPS诱导的HT-29细胞NF-κB信号通路上IκBα蛋白的降解,0.100 μg/mL作用较为明显,与空白对照组比较有显著性差异(P<0.01)。研究明确地证实了乳源CGMP可通过抑制p-IκBα、E3RSIκB、UBC5蛋白的表达来抑制IκBα蛋白的降解,进而抑制NF-κB信号通路的激活。结论:乳源CGMP可显著降低NF-κB信号通路关键蛋白IκBα的降解,其机制是抑制了IκBα的磷酸化和泛素化,使p-IκBα和泛素化关键蛋白E3RSIκB和UBC5的表达均有所下降,进而减少了IκBα的降解,增加了IκBα-p65-p50蛋白三聚体的数量,使p65蛋白核移位效应降低,进而减少下游基因的表达。因此,研究结果科学地阐释了乳源CGMP是通过调控NF-κB信号通路发挥抗炎的作用。

关键词: 酪蛋白糖巨肽, 结肠癌细胞, 核因子-κB, 磷酸化核因子-κB抑制因子α, 泛素-蛋白连接酶亚单位

Abstract: This study was undertaken to determine the effect of casein glycomacropeptide (CGMP) on the p65 subunit of nuclear factor-κB (NF-κB) of HT-29 human colon cancer cells challenged with lipopolysaccharide (LPS). Furthermore, Western blotting technology was used to detect and compared the expression levels of the key proteins involved in the NF-κB signaling pathway such as IκBα, p-IκBα, E3RSIκB and UBC5 in the control group, milk-derived CGMP group and LPS group to uncover the molecular mechanism of CGMP in regulating the NF-κB signaling pathway. The results showed that all three doses of CGMP (0.001, 0.010 and 0.100 μg/mL) could suppress the degradation of IκBα in some degree, which is involved in the NF-κB signaling pathway of HT-29 cells challenged with LPS and this effect was more significant at the dose of 0.100 μg/mL, which was significantly different when compared with the control group (P < 0.01). Therefore, it was confirmed that CGMP could suppress the degradation of IκBα by repressing the expression of p-IκBα, E3RSIκB and UBC5, thereby inhibiting the activation of the NF-κB signaling pathway. As a result, CGMP can significantly reduce the degradation of IκBα in the NF-κB signal pathway, increase the amount of protein trimer-IκBα-p65-p50 and decrease nuclear translocation of p65 and downstream gene expression by inhibiting the phosphorylation and ubiquitination of IκBα and reducing the expression of p-IκBα and key ubiquitin proteins (E3RSIκB and UBC5). This study illustrates that milk-derived CGMP plays an anti-inflammatory role by regulating the NF-κB signal pathway.

Key words: casein glycomacropeptide, colon cancer cells (HT-29), nuclear factor-κB, IκBα, ubiquitin-protein ligase subunit

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