Objective: To explore the effects of B-cell lymphoma-2/adenovirus E1B 19 000 interacting protein 3 (BNIP3) on the migration and motility of human dermal microvascular endothelial cells (HDMECs) under hypoxia and the mechanism. Methods: The experimental research method was applied. (1) HDMECs were divided into normoxia group received routine culture and hypoxia 6, 12, 24 h groups treated under hypoxia with oxygen volume fraction of 2% for corresponding time according to the random number table (the same grouping method below). Western blotting was used to detect the protein expressions of BNIP3 and microtubule-associated protein 1 light chain 3Ⅱ (LC3Ⅱ) in HDMECs. (2) HDMECs were divided into normoxia+ unloaded group, normoxia+ BNIP3 knockdown group, hypoxia+ unloaded group, and hypoxia+ BNIP3 knockdown group which were transfected with unloaded virus or BNIP3 knockdown virus and were subjected to normoxic or hypoxic treatment. The BNIP3 protein expression was detected by Western blotting and immunofluorescence staining. The scratch area at 24 h post scratching was detected by scratch test, and the healing rate of scratch was calculated. The curve distance of cell movement was measured with the living cell workstation, and the speed of movement was calculated within 3 hours. (3) HDMECs were grouped and treated as experiment (2). Western blotting and immunofluorescence staining were performed to detect the protein expression of LC3Ⅱ. The number of sample was 3 in the above-mentioned experiments. Data were statistically analyzed with one-way analysis of variance and least significant difference test. Results: (1) Compared with those of normoxia group, the protein expressions of BNIP3 and LC3Ⅱ of cells in hypoxia 6, 12, 24 h groups were significantly increased (P<0.01). (2) After 6 hours of culture, compared with that of hypoxia+ unloaded group, the BNIP3 protein expressions of cells in normoxia+ unloaded group and hypoxia+ BNIP3 knockdown group were significantly decreased (P<0.05 or P<0.01). The red fluorescence denoting BNIP3 protein expression of cells in normoxia+ unloaded group and normoxia+ BNIP3 knockdown group was weak, the red fluorescence of cells in hypoxia+ unloaded group was strong, and the red fluorescence of cells in hypoxia+ BNIP3 knockdown group was significantly decreased compared with that in hypoxia+ unloaded group. After scratching for 24 hours, the scratch of cells in hypoxia+ unloaded group basically healed, while the remaining scratch area in the other three groups were large. The healing rates of scratch of cells in normoxia+ unloaded group, normoxia+ BNIP3 knockdown group, hypoxia+ unloaded group, and hypoxia+ BNIP3 knockdown group were (61±4)%, (58±4)%, (88±4)%, and (57±4)%, respectively. The healing rate of scratch of cells in hypoxia+ unloaded group was significantly higher than that in normoxia+ unloaded group (P<0.01) and hypoxia+ BNIP3 knockdown group (P<0.05). Within 3 hours of observation, the range of cell movement in hypoxia+ unloaded group was significantly larger than that in normoxia+ unloaded group, the range of cell movement in hypoxia+ BNIP3 knockdown group was significantly smaller than that in hypoxia+ unloaded group, and the curve movement velocity of cells in hypoxia+ unloaded group was significantly higher than that in normoxia+ unloaded group and hypoxia+ BNIP3 knockdown group (P<0.01). (3) After 6 hours of culture, compared with hypoxia+ unloaded group, the LC3Ⅱ protein expressions of cells in hypoxia+ unloaded group and hypoxia+ BNIP3 knockdown group were decreased significantly (P<0.05 or P<0.01). After 6 hours of culture, the red fluorescence denoting LC3 protein expressions of cells was weak in normoxia+ unloaded group and normoxia+ BNIP3 knockdown group, the red fluorescence of cells was significantly enhanced in hypoxia+ unloaded group, and the red fluorescence of cells was significantly inhibited in hypoxia+ BNIP3 knockdown group. Conclusions: BNIP3 can promote the migration and motility of HDMECs under hypoxia, and autophagy may be involved in the regulation migration of HDMECs by BNIP3.
目的： 探讨低氧条件下B淋巴细胞瘤-2/腺病毒E1B 19 000相互作用蛋白3(BNIP3)对人真皮微血管内皮细胞(HDMEC)迁移和运动性的影响及其机制。 方法： 采用实验研究方法。(1)取HDMEC，采用随机数字表法(下同)分成行常规培养的常氧组及采用体积分数2%氧气低氧处理相应时间点的低氧6、12、24 h组，采用蛋白质印迹法检测细胞中BNIP3及微管相关蛋白1轻链3Ⅱ(LC3Ⅱ)的蛋白表达。(2)取HDMEC，分成常氧＋空载组、常氧＋BNIP3敲减组、低氧＋空载组、低氧＋BNIP3敲减组，分别转染空载病毒或BNIP3敲减病毒并进行常氧或低氧处理6 h，采用蛋白质印迹法和免疫荧光染色法检测BNIP3的蛋白表达；采用划痕试验检测划痕后24 h的划痕面积，并计算划痕愈合率；在活细胞工作站测算3 h内细胞运动的曲线距离，计算运动速度。(3)取HDMEC，同实验(2)分组及处理，采用蛋白质印迹法和免疫荧光染色法检测LC3Ⅱ的蛋白表达。以上实验样本数均为3。对数据行单因素方差分析及LSD检验。 结果： (1)与常氧组比较，低氧6、12、24 h组细胞BNIP3及LC3Ⅱ的蛋白表达量显著增加(P<0.01)。(2)培养6 h，与低氧＋空载组比较，常氧＋空载组和低氧＋BNIP3敲减组细胞BNIP3的蛋白表达量显著下降(P<0.05或P<0.01)。常氧＋空载组和常氧＋BNIP3敲减组细胞中表示BNIP3蛋白表达的红色荧光较弱，低氧＋空载组细胞红色荧光较强，低氧＋BNIP3敲减组细胞中红色荧光较低氧＋空载组明显减弱。划痕后24 h，低氧＋空载组细胞划痕基本愈合，其他3组细胞剩余划痕面积较大。常氧＋空载组、常氧＋BNIP3敲减组、低氧＋空载组、低氧＋BNIP3敲减组细胞划痕愈合率分别为(61±4)%、(58±4)%、(88±4)%、(57±4)%。低氧＋空载组细胞划痕愈合率明显高于常氧＋空载组(P<0.01)和低氧＋BNIP3敲减组(P<0.05)。观察3 h内，低氧＋空载组细胞运动范围较常氧＋空载组显著增大，低氧＋BNIP3敲减组细胞运动范围较低氧＋空载组明显缩小；低氧＋空载组细胞曲线运动速度较常氧＋空载组和低氧＋BNIP3敲减组明显增加(P<0.01)。(3)培养6 h，与低氧＋空载组比较，常氧＋空载组和低氧＋BNIP3敲减组细胞LC3Ⅱ的蛋白表达量显著下降(P<0.05或P<0.01)。培养6 h，常氧＋空载组和常氧＋BNIP3敲减组细胞中表示LC3蛋白表达的红色荧光较弱，低氧＋空载组细胞红色荧光明显增强，低氧＋BNIP3敲减组细胞红色荧光被显著抑制。 结论： 低氧条件下BNIP3可促进HDMEC的迁移和运动性，且自噬可能参与BNIP3对HDMEC迁移和运动性的调节。.
Keywords: Autophagy; B-cell lymphoma-2/adenovirus E1B 19 000 interacting protein 3; Cell hypoxia; Cell migration assays; Cell movement; Human dermal microvascular endothelial cell.