Objective: To investigate the expression of peptidylarginine deiminase 4 (PADI4) during the process of differentiation into granulocyte of NB4 cells induced by all-trans-retinoic acid (ATRA) and whether PADI4 is involved in the inflammatory cytokines expression.
Methods: Granulocyte differentiation model of NB4 cells induced by ATRA was established. The cell morphology changes were observed by Wright-Giemsa staining. The expression of cell differentiation marker CD11b was analyzed by flow cytometry. The mRNA and protein expression of PADI4 was detected by RT-PCR and Western blot, respectively. The expression of tumor necrosis factor (TNF) α and interleukin (IL) 1β was analyzed by ELISA, and also examined with the knockdown of PADI4 expression by siRNA.
Results: After NB4 cells induced by ATRA, the cytoplasm increased and the ratio of nuclear to cytoplasmic was reduced. Nuclear dented, and rod-shaped nucleus, lobulated phenomenon increased (P<0.05). Flow cytometry analysis results showed that the cell surface molecule CD11b expression increased (P<0.01). RT-PCR and Western blot showed the expression of PADI4 increased at both transcriptional and translational levels during the process of the differentiation. ELISA showed TNF-α and IL-1β secretion increased in differentiated macrophages, while they could be inhibited by PADI4-specific siRNA.
Conclusion: During the differentiation into granulocyte of NB4 cells induced by ATRA, PADI4 expression increased. Furthermore, PADI4 appeared to play a critical role in inflammatory cytokines secretion.
题目: PADI4对NB4细胞分化过程中炎性因子表达水平的影响.
目的: 探讨全反式维甲酸（ATRA）诱导人急性早幼粒细胞白血病细胞株NB4向粒细胞分化过程中肽酰基精氨酸脱亚胺酶4（PADI4）的表达变化及其是否参与炎性因子的表达.
方法: 建立ATRA诱导的NB4细胞分化模型，采用Wright-Giemsa染色观察细胞形态学变化；采用流式细胞术检测细胞表面分化抗原CD11b的表达；RT-PCR方法检测PADI4基因转录水平的表达；Western bolt方法检测PADI4翻译水平的表达；ELISA检测培养液中肿瘤坏死因子（TNF）-α和白细胞介素（IL）-1β的表达；siRNA技术干扰PADI4表达后ELISA检测TNF-α和IL-1β的表达.
结果: ATRA诱导后NB4细胞胞浆增多，核浆比例降低，核有凹陷，杆状和分叶现象增多。流式细胞术检测结果显示细胞表面分子CD11b表达明显升高(P<0.01)。在分化模型中，RT-PCR及Western blot检测结果显示PADI4转录水平和翻译水平表达均明显升高(P<0.05)。ELISA方法检测培养液中TNF-α和IL-1β的表达水平明显升高(P<0.05)，而siRNA技术干扰PADI4表达后TNF-α和IL-1β的表达水平明显下降(P<0.05).
结论: ATRA诱导NB4细胞向粒细胞分化过程中PADI4的表达升高，同时PADI4参与了NB4细胞分化过程中炎性因子的表达.