IL-6显著调节亚油酸棕榈酸联合诱导脂肪肝细胞模型中脂代谢的通路表达

IL-6 trans-signaling in an L-02 fatty liver cell model induced with sodium oleate and sodium palmitate

目的:探讨白介素-6(interleukin-6,IL-6)在亚油酸(sodium oleate)、棕榈酸(sodium palmitate)联合诱导L-02脂肪肝细胞模型中的可能作用机理.方法:将亚油酸和棕榈酸作用于人肝细胞株L-02形成脂肪浸润的肝脏细胞模型.实时定量PCR和ELISA检测细胞内及外分泌IL-1β、IL-6和IL-17α的表达水平,Western blot检测细胞胰岛素受体底物1(insulin receptor substrate 1,IRS-1),Grb2相关结合蛋白2(Grb2-associated binder 2,Gab2),磷脂酰肌醇3-激酶(phosphoinositide-3-kinase,PI3K),蛋白激酶B(protein kinase B,AKT)和细胞因子信号抑制因子-3(suppressor of cytokine signaling-3,S O C S3)的信号表达.蛋白芯片方法检测对照组以及脂肪肝模型组中IL-6下游信号通路蛋白质分子的磷酸化水平.结果:在脂肪酸处理的肝脏L-02细胞中,IL-6在细胞内外表达均明显升高,IL-17α在体外肝脏细胞表达无变化,IL-1β在体外肝脏细胞内m RNA水平表达显著升高,但是在细胞外无分泌(P<0.05).IRS-1、Gab2、a-tubulin、PI3K、A K T和S O C S3在两者细胞中表达差异无统计学意义.蛋白芯片研究发现IL-6下游Shc/E R K信号通路(S h c,E R K)、m TO R信号通路(p70S6K)及P I3K/A K T信号通路(A K T2)均有激活,而下游核因子-κB(nuclear factor-κB,NF-κB)信号通路可能受到抑制(IKKβ).此外,IL-6能够引起磷酸化的GSK3β、PKCζ、e IF4E等分子的磷酸化水平也显著上调.结论:IL-6在脂代谢中发挥重要的作用.L-02细胞脂肪浸润过程中,IL-6表达量上调并分泌后,其下游信号通路被广泛激活.

AIM： To investigate interleukin-6（IL-6） transsignaling in an L-02 fatty liver cell model induced with sodium oleate and sodium palmitate. METHODS： Sodium oleate and sodium palmitate were added into L-02 cells to induce fat accumulation in liver cells. Real-time PCR and enzyme-linked immunosorbent assay（ELISA） were used to detect the concentrations of IL-1β, IL-6 and IL-17α in model cells. The expression of insulin receptor substrate-1（IRS-1）, Grb2-associated binder 2（Gab2）, α-tubulin, phosphoinositide-3-kinase（PI3K）, protein kinase B（AKT） and suppressor of cytokine signaling-3（SOCS3） was detected by Western blot. Phosphorylation of IL-6 trans-signaling associated proteins was detected with protein chip. RESULTS： The concentration of IL-6 was significantly elevated in the L-02 fatty liver cell model, while there was no significant increase in IL-17α concentration（P 〈 0.05）. The m RNA level of IL-1β was significantly elevated in the L-02 fatty liver cell model, although it was not detectable in cell culture medium（P 〈 0.05）. The expression of IRS-1, Gab2, α-tubulin, PI3 K, AKT and SOCS3 showed no differences between model and control cells. IL-6 downstream signaling molecules Shc/ERK（Shc, ERK）, m TOR（p70S6K）, and PI3K/AKT（AKT2） were all activated, while nuclear factor-κB（NF-κB） was inhibited（IKKβ）. Furthermore, the phosphorylation of GSK3β, PKCζ and e IF4 E was significantly up-regulated. CONCLUSION： IL-6 plays a key role in fat acid metabolism. The expression of IL-6 is significantly elevated and its downstream signaling molecules are widely activated in the L-02 fatty liver cell model.