Effects of B-cell lymphoma-2/adenovirus E1B 19 000 interacting protein 3 on the migration and motility of human dermal microvascular endothelial cells under hypoxia and the mechanism

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 (

<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 (

<0.05 or

<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 (

<0.01) and hypoxia+ BNIP3 knockdown group (

<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 (

<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 (

<0.05 or

<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.