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Aim To explore the effect of γ-ray on the mRNA,protein expression levels and metabolic activity level of the key drug metabolic enzyme CYP3A1 in rat liver. Methods Wistar rats were randomly divided into control group, 24 h post-radiation group and 72 h post-radiation group. The experimental group was exposed to total body irradiation of single 6 Gy γ-ray. Blood was collected from the orbital venous plexus for blood routine examination and biochemical analysis 24 h and 72 h after irradiation, and liver tissue was prepared for quantifying expression of CYP3A1 mRNA and liver-specific microRNA (miR-122-5p) through RT-PCR. The expression level of CYP3A1 protein was analyzed by Western blot, and the metabolic activity level of CYP3A1 detected by the specific substrate midazolam combined with LC-MS method. Results Com¬pared with the control group, the weights of the rats in the radiation group significantly decreased, and the number of white blood cells was markedly reduced. Simultaneously, the activities of alanine aminotrans-ferase and alkaline phosphatase continuously descended, as well as the levels of total bilirubin and bile acid significantly increased, which indicated that the liver may be damaged after radiation. The relative expression of CYP3A1 mRNA continued to increase significantly 24 h and 72 h after irradiation. CYP3A1 protein expression and metabolic activity levels showed an obvious increasing trend 24 h after irradiation, and rose significantly 72 h after irradiation compared with the control group. At the same time, the expression of miR-122-5p in liver of rats in the 24 h and 72 h post-radiation group continued to decrease rapidly compared with the control group. Conclusions γ-ray radiation may arouse damage effect on liver, which leads to the continuous up-regulation of the mRNA and protein expression levels of the capital metabolic enzyme CYP3A1 in liver tissue, as well as the elevation of the metabolic activity level. The regulatory mechanism might be related to miR-122-5p.
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Objective:To determine the effect of miR-122-5p on microglia polarization, apoptosis and inflammation after traumatic brain injury (TBI).Methods:A mouse model and an in vitro TBI model were established. Astrocytes were stimulated to synthesize and release exosomes by brain extracts. microRNA microarray analysis was used to analyze the significantly altered microRNAs. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was applied to detect the expression of miR-122-5p in the in vivo and in vitro TBI model. TUNEL, immunofluorescence, and Western blot were performed to detect the effects of miR-122-5p inhibitors on microglia apoptosis, microglia M1/M2 phenotype transformation and the activation of NLRP3 inflammasome pathway and the phosphorylation of NF-κB after TBI.Results:The results of microRNA microarray analysis showed that 83 miRNAs were downregulated significantly (altered more than 2 folds, P < 0.05), among which miR-122-5p was significantly down-regulated ( P < 0.01). Expression of miR-122-5p was significantly decreased in the in vivo and in vitro TBI model [(1.00±0.00) vs. (0.41±0.15), P < 0.001; (1.00±0.00) vs. (0.34±0.07), P < 0.001]. TUNEL and immunofluorescence showed that miR-122-5p inhibitor significantly alleviated microglia apoptosis[(8.03±1.30) vs. (3.17±0.34), P < 0.001] and promoted microglia M1→M2 phenotype transformation ,M1 phenotype polarization was reduced [(56.96±13.70) vs. (34.70±3.47), P =0.002] and M2 phenotype polarization was increased [(30.46±3.67) vs. (40.74±2.49), P =0.005]. Western blot showed that NLRP3 inflammasome activation was inhibited and NF-κB phosphorylation was decreased when miR-122-5p was downregulated[(0.77±0.10) vs. (0.51±0.11), P =0.02; (0.73±0.08) vs. (0.50±0.07), P =0.003]. Conclusions:miR-122-5p is downregulated in microglia and exosomes secreted by astrocytes after TBI. miR-122-5p inhibitor can attenuate the microglia inflammatory response after TBI by inhibiting the activation of NLRP3 inflammasome pathway and the phosphorylation of NF-κB, promoting the microglia M1→M2 phenotypic transformation and reducing microglia apoptosis, thereby reducing the microglia inflammatory injury after TBI.
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OBJECTIVE@#To investigate the expression profile of miR-122-5p in melanoma tissues and the effect of miR-122-5p on the proliferation, cell cycle and apoptosis of human melanoma cell lines SK-MEL-110 and A375.@*METHODS@#The expression profiles of miR-122-5p in melanoma and pigmented nevus tissues were detected using real-time fluorescence quantitative PCR (qRT-PCR). SK-MEL-110 and A375 cells transfected with miR-122-5p inhibitor or negative control inhibitor (NC) I were examined for miR-122- 5p expression using qRT-PCR and changes in cell proliferation, cell cycle and apoptosis using MTT assay or flow cytometry. NOP14 mRNA and protein expressions in the cells were detected using qRT- PCR and Western blotting, respectively. Luciferase reporter assay was used to confirm the identity of NOP14 as the direct target of miR-122-5p.@*RESULTS@#The relative expression of miR-122-5p in human pigmented nevus tissues and melanoma tissues was 1.23±0.270 and 7.65 ± 1.37, respectively. The relative expression of miR-122-5p in SK-MEL-110 and A375 cells transfected with miR-122-5p inhibitor was 0.21 ± 0.08 and 0.17 ± 0.05, respectively. miR-122-5p inhibitor obviously inhibited the cell proliferation and increased the percentage of cells in G1 stage in both SK-MEL-110 and A-375 cells, but did not cause obvious changes in the apoptosis of the two cells. miR-122-5p inhibitor did not significantly affect the expression level of NOP14 mRNA, but obviously increased the expression level of NOP14 protein. Luciferase reporter assay revealed a significantly lower luciferase activity in cells co-transfected with miR-122-5p mimics and wild-type psi-CHECK2-3'UTR plasmid than in the cells cotransfected with NC and wild-type psi-CHECK2-3'UTR plasmid (0.21 ± 0.14 0.56 ± 0.1, < 0.01).@*CONCLUSIONS@#miR-122-5p expression is upregulated in melanoma tissues, indicating its involvement in the development of melanoma. miR-122-5p inhibits the proliferation of SK-MEL-110 and A-375 cells possibly by affecting the cycle through NOP14.