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Objective:To study the role of miRNA-15b and vascular endothelial growth factor (VEGF) in the pathogenesis of novel bronchopulmonary dysplasia (nBPD) in rats.Methods:A total of 100 newborn SD rats were randomly assigned into BPD group and control group with 50 rats in each group. The BPD group was placed in oxygen chamber with 60% oxygen concentration and the control group received atmospheric air. The morphological changes of lung tissues were observed on 1 d, 7 d, 14 d and 21 d and the radial alveolar counts (RAC) and alveolar septal thickness (AST) were measured. The expression of miR-15b was measured using real-time quantitative PCR and the expression of VEGF in lung tissue was examined using ELISA method.Results:With prolonged oxygen exposure, the lung tissue of the BPD group showed a decrease in the number of alveoli, a gradual loss of the normal structure of alveoli and a significant widening of the alveolar septum. On 7 d, 14 d and 21 d, RAC values [(6.19±0.29) vs. (6.86±0.92), (5.35±0.67) vs.(9.75±0.34), (3.96±0.45) vs. (10.04±0.52)] were significantly lower in the BPD group than the control group ( P<0.05). On 7 d, 14 d and 21 d,the levels of AST in BPD group were significantly higher than the control group [(6.87±0.41) μm vs. (6.43±0.31) μm, (8.94±0.25) μm vs. (5.36±0.26) μm, (9.61±0.30) μm vs. (4.55±0.32) μm] ( P<0.05). On 7 d, 14 d and 21 d,the miR-15b expression in BPD group were significantly higher than the control group [(1.12±0.11) vs. (0.84±0.09), (1.33±0.09) vs. (0.73±0.07), (1.66±0.15) vs. (0.45±0.10)] ( P<0.05).On 7 d, 14 d and 21 d, VEGF in BPD group were significantly lower than the control group [(10.89±1.67) pg/ml vs. (23.86±4.38) pg/ml, (8.75±1.28) pg/ml vs. (53.94±3.49) pg/ml, (4.66±1.12) pg/ml vs. (70.37±3.10) pg/ml] ( P<0.05). Conclusions:MiR-15b and VEGF may play a role in the development of nBPD.
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Objective To explore the inhibitory effects of miR-15 b-5 p on choroid melanoma cell line proliferation by targeting CDK4.Methods Dual-luciferase assay was used to verify the direct binding site between miR-15 b-5 p and CDK4 3'-UTR. MUM-2 B cells were cultured in vitro and transfected with negative control RNA, miR-15 b-5 p mimics, inhibitor normal control (nc) RNA, and miR-15 b-5 p inhibitor. qRT-PCR was used to detect miR-15 b-5 p expression, Western blotting was used to measure the expression levels of CDK4 in the cells, CCK-8 assay was used to detect proliferation capacity, and flow cytometry was used to detect cell cycle. Results Dual-luciferase assay verified that miR-15 b-5 p could bind to CDK4 mRNA 3'-UTR successfully. Compared to the negative control group, the mimics group showed significantly increased miR-15 b-5 p expression, decreased CDK4 levels, decreased cell proliferation rate, and increased proportion of G1-phase cells. Compared to the inhibitor nc group, the inhibitor group showed significantly decreased miR-15 b-5 p expression (t = 25.01, P ＜ 0.000 1), increased CDK4 protein level, increased cell proliferation rate, and decreased proportion of G1-phase cells.Conclusion miR-15 b-5 p can target CDK4, induce G1 phase arrest in cells, and thus, reduce the proliferation rate of choroid melanoma cells.
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@#Objective To construct dual-luciferase reporter plasmids containing the wild type and mutant rat extracellular signal-regulat-ed kinase 1 (ERK1) gene 3' untranslated regions (UTR) which were used to detect rno-miR-15b-5p's putative target gene. Methods The rat ERK1 gene 3' UTR fragment was amplified by polymerase chain reaction (PCR) from PC12 cell cDNA and cloned into pmiR-RB-ReportTM vector. The mutant rat ERK1 gene 3' UTR fragment was obtained by overlap PCR and inserted into pmiR-RB-ReportTM vector. Successful wild type and mutant recombinant plasmids were confirmed by DNA sequencing. PC12 cells were co-transfected with rno-miR-15b-5p mim-ic and pmiR-ERK13' UTR or pmiR-ERK1-mut 3' UTR and then analyzed by dual-luciferase reporter assay system. The achieved mutation sequence of the target site TGCTGCT was mutated to CGAACGT and GTACACG, respectively. Results The wild-type reporter vector pmiR-ERK13' UTR and the mutant reporter vector pmiR-ERK1-mut 3' UTR were successfully constructed. The rno-miR-15b-5p mimic de-creased the activity of pmiR-ERK13' UTR plasmid (P<0.001) but did not decrease the activity of pmiR-ERK1-mut 3' UTR plasmid. Conclu-sion The recombinant pmiR-ERK13' UTR and pmiR-ERK1-mut 3' UTR plasmids were constructed successfully, and luciferase activities demonstrated that the 3' UTR of ERK1 gene might be a potential target of rno-miR-15b-5p.