CAJ | 학술논문

目的探讨激活视黄醇类X受体(RXR)对轻度氧化低密度脂蛋白(LoxLDL)诱导巨噬细胞增殖的影响及其作用机制.方法饥饿处理后的小鼠巨噬细胞系RAW264.7经LoxLDL(20μg/ml)刺激24 h诱导细胞增殖,干预组同时给予不同浓度的RXR特异性激动剂顺式维甲酸9(9-cisRA),四甲基偶氮唑蓝方法检测细胞活力,脱氧尿嘧啶核苷免疫组化方法检测细胞DNA合成,流式细胞仪PI单染法检测细胞凋亡,Western印迹方法检测Nur77和RARB蛋白表达.结果 LoxLDL诱导24 h后,细胞活力和DNA合成(A值)分别升高0.79±0.12和1.81±0.31,RXR的特异性配体9-cisRA能够显著抑制LoxLDL的作用,在10-8mol/L和10-7mol/L浓度分别使细胞活力下降到0.43±0.10和0.26±0.07(P＜0.05),DNA合成升高为1.14±0.43和0.72±0.06(P＜0.05),且对细胞凋亡没有影响.Western印迹检测表明,孤儿核受体Nur77蛋白表达在LoxLDL刺激后显著升高5倍以上,9-cisRA显著下调Nur77表达,同时上调下游靶基因RARB蛋白表达.结论激活核受体RXR能够显著抑制LoxLDL刺激引起的巨噬细胞增殖,其机制可能与调控RXR/Nur77异源二聚体及其下游靶基因RARβ有关.
목적 탐토격활시황순류X수체(RXR)대경도양화저밀도지단백(LoxLDL)유도거서세포증식적영향급기작용궤제.방법 기아처리후적소서거서세포계RAW264.7경LoxLDL(20μg/ml)자격24 h유도세포증식,간예조동시급여불동농도적RXR특이성격동제순식유갑산9(9-cisRA),사갑기우담서람방법검측세포활력,탈양뇨밀정핵감면역조화방법검측세포DNA합성,류식세포의PI단염법검측세포조망,Western인적방법검측Nur77화RARB단백표체.결과 LoxLDL유도24 h후,세포활력화DNA합성(A치)분별승고0.79±0.12화1.81±0.31,RXR적특이성배체9-cisRA능구현저억제LoxLDL적작용,재10-8mol/L화10-7mol/L농도분별사세포활력하강도0.43±0.10화0.26±0.07(P＜0.05),DNA합성승고위1.14±0.43화0.72±0.06(P＜0.05),차대세포조망몰유영향.Western인적검측표명,고인핵수체Nur77단백표체재LoxLDL자격후현저승고5배이상,9-cisRA현저하조Nur77표체,동시상조하유파기인RARB단백표체.결론 격활핵수체RXR능구현저억제LoxLDL자격인기적거서세포증식,기궤제가능여조공RXR/Nur77이원이취체급기하유파기인RARβ유관.
Objective To investigate the effects and mechanism of retinoid X receptor (RXR) activation on macrophages proliferation induced by lightly oxidized low-density lipoprotein (LoxLDL).Methods Serum-starved mouse macrophages of the line RAW264. 7 were stimulated with 20 μg/mLLoxLDL for 24 h to induce proliferation in the absence or presence of varying doses of RXR special agonist 9-cis retinoid acid (RA). The cell viability was assayed by MTT method. The DNA synthesis was assayed by BrdU ELISA. The apoptotic percentage of cells was measured by flow cytometry using propidium iodide (PI) staining. Nur77 and RARβ protein expressions were detected by Western blotting. Results After treated by LoxLDL for 24 h, the cell viability and DNA synthesis ( A value) of the RAW264.7 ceils were increased by 0.79±0.12 and 1.81±0.31 respectively. Co-incubated with LoxLDL and 10-s mol/L and 10-7 mol/L 9-cisRA the ceil viability decreased to 0.43±0.10 and 0.26±0.07 respectively( both P＜0. 05 ), and the DNA synthesis decreased to 1.14±0.43 and 0.72±0.06 respectively(both P＜0.05 ) The apoptotic rate of the ceils treated with LoxLDL was (3.08±0.30) %, not significantly different from those of the cells cocultured with LoxLDL and 10-9-10-7 mol/L 9-cisRA (2.74±0.13 ) % , (2.94±0.24) % , and (2.48±0.42) % respectively, all P＞0.05. The orphan nuclear receptor Nur77 protein expression was up-regulated by more than 5 times after LoxLDL treatment. 9-cisRA down-regulates the Nut77 expression and increased the expression of the downstream gene RARβ. Condnsion RXR activation significantly inhibits the macrophage proliferation induced by LoxLDL. The mechanism may be related to the regulation of RXR/Nur77 heterodimer and its downstream gene RARβ.