Lou Ye-jiang, Pan Xiao-rong, Xu Gui-ping, Zhuang Li-kun, Jia Pei-min, Tong Jian-hua
Shanghai Jiaotong University School of Medicine, Shanghai, China.
Zhonghua Yi Xue Za Zhi. 2012 Jan 10;92(2):124-7.
To explore the relationship between interferon (IFN) α and all-trans retinoic acid (ATRA)-induced signaling pathways in the expression of retinoic acid-induced gene G (RIG-G).
Acute promyelocytic leukemia cell line NB4 and signal transducer and activator of transcription (STAT)1-deficient U3A cells were used. The protein levels of tyrosine-phosphorylated STAT2 in ATRA-treated NB4 cells were detected by Western blot. The culture supernatants of NB4 cells treated with ATRA for different time or U3A cells transfected with interferon regulatory factor (IRF)-1 were respectively collected. And the concentration of IFN-α was determined by enzyme-linked immunosorbent assay (ELISA). The effects of NB4 cell culture supernatants on the phosphorylation of STAT2 and the expression of RIG-G were detected by Western blot.
The level of phosphorylated-STAT2 was obviously up-regulated in NB4 cells treated with ATRA for 72 hours, as well as the concentration of IFN-α in culture supernatants. The concentration of IFN-α increased from (1.5 ± 0.5) pg/ml in the untreated group to (7.6 ± 0.3) pg/ml (P < 0.05). After a 96-hour treatment, the concentration of IFN-α was up to (63.8 ± 5.8) pg/ml. And these culture supernatants could induce the tyrosine phosphorylation of STAT2 and up-regulate the protein level of RIG-G. As for U3A cells transfected with IRF-1, the concentration of IFN-α from the culture supernatant also increased 3-fold versus the control group transfected with empty vectors [(8.8 ± 1.4) pg/ml vs (3.4 ± 0.4) pg/ml, P < 0.05].
RIG-G gene expression is closely correlated with the cross-talk between ATRA and IFN-α-induced signaling pathways. ATRA increases the secretion of IFN-α by up-regulating the protein level of IRF-1. Then the secreted IFN-α may induce the phosphorylation of STAT2 and reinforce the expression of RIG-G.
探讨干扰素（IFN）α与全反式维甲酸（ATRA）诱导的信号通路在维甲酸诱导基因G（RIG-G）表达中的关系。
使用急性早幼粒细胞白血病细胞系NB4和信号转导及转录激活因子（STAT）1缺陷的U3A细胞。通过蛋白质印迹法检测经ATRA处理的NB4细胞中酪氨酸磷酸化STAT2的蛋白水平。分别收集经不同时间ATRA处理的NB4细胞或转染了干扰素调节因子（IRF）-1的U3A细胞的培养上清液。采用酶联免疫吸附测定（ELISA）法测定IFN-α的浓度。通过蛋白质印迹法检测NB4细胞培养上清液对STAT2磷酸化及RIG-G表达的影响。
经ATRA处理72小时的NB4细胞中，磷酸化STAT2水平明显上调，培养上清液中IFN-α浓度也升高。IFN-α浓度从未处理组的（1.5±0.5）pg/ml增加至（7.6±0.3）pg/ml（P<0.05）。处理96小时后，IFN-α浓度高达（63.8±5.8）pg/ml。这些培养上清液可诱导STAT2的酪氨酸磷酸化并上调RIG-G的蛋白水平。对于转染了IRF-1的U3A细胞，其培养上清液中IFN-α浓度较转染空载体的对照组也增加了3倍[（8.8±1.4）pg/ml对（3.4±0.4）pg/ml，P<0.05]。
RIG-G基因表达与ATRA和IFN-α诱导的信号通路之间的相互作用密切相关。ATRA通过上调IRF-1蛋白水平增加IFN-α的分泌。然后分泌的IFN-α可能诱导STAT2磷酸化并增强RIG-G的表达。
