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Objective:To evaluate the role of Notch1/hairy and enhancer of split homolog1(Hes1) signaling pathway in high glucose and hypoxia-reoxygenation (H/R) injury to cardiomyocytes.Methods:H9c2 cardiomyocytes were cultured in low-glucose DMEM culture medium supplemented with 10% fetal bovine serum.The cells were divided into 6 groups ( n=12 each) using a random number table method: control group (group C), H/R group, H/R+ Jagged-1 group (group H/R+ J), high glucose group (group HG), high glucose+ H/R group (group HG+ H/R) and high glucose+ H/R+ Jagged-1 group (group HG+ H/R+ J). The cells were incubated in low-glucose culture medium for 72 h in group C. After incubated in low-glucose culture medium for 72 h, the cells were exposed to 24-h hypoxia in an incubator filled with 95% N 2-5% CO 2 at 37℃, immediately followed by 6-h reoxygenation in an incubator filled with 95% O 2-5% CO 2 at 37℃ in group H/R.In group H/R+ J, Jagged-1 (Notch1/Hes1 signaling pathway specific activator) 5μg/ml was added to low-glucose culture medium and the cells were incubated for 72h before H/R.In group HG, H9c2 cardiomyocytes were incubated in high-glucose culture medium containing 33 mmol/L glucose for 72 h. In group HG+ H/R, the cells were incubated in high-glucose medium for 72 h before H/R.In group HG+ H/R+ J, Jagged-1 5μg/ml was added to high-glucose culture medium, and the cells were incubated for 72 h before H/R.At 6 h of reoxygenation, the supernatant of the culture medium was collected for detection of the activities of superoxide dismutase (SOD) and lactic dehydrogenase (LDH), the cell viability (by CCK-8 assay) and the cell apoptosis rate (by flow cytometry) and for determination of expression of Notch1, Hes1 and c-caspase-3 (by Western blot). Results:Compared with group C, the cell survival rate and SOD activity were significantly decreased, and apoptosis rate and LDH activity were increased in H/R, H/R+ J and HG groups, expression of Notch1, Hes1 and c-caspase-3 was up-regulated in H/R and H/R+ J groups, and the expression of Notch1 and Hes1 was down-regulated and c-caspase-3 expression was up-regulated in group HG ( P<0.05). Compared with group H/R, the cell survival rate and SOD activity was significantly increased, apoptosis rate and LDH activity were decreased, expression of Notch1 and Hes1 was up-regulated, and c-caspase-3 expression was down-regulated in group H/R+ J, and the cell survival rate and SOD activity were significantly decreased, apoptosis rate and LDH activity were increased, expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG, the cell survival rate and SOD activity were significantly decreased, and apoptosis rate and LDH activity were increased in HG+ H/R and HG+ H/R+ J groups ( P<0.05), and expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R ( P<0.05). Compared with group HG+ H/R, the cell survival rate and SOD activity were significantly increased, apoptosis rate and LDH activity were decreased, expression of Notch1 and Hes1 was up-regulated, and c-caspase-3 expression was down-regulated in group HG+ H/R+ J ( P<0.05). Compared with group H/R+ J, the cell survival rate and SOD activity were significantly decreased, apoptosis rate and LDH activity were increased, expression of Notch1 and Hes1 was down-regulated, and c-caspase-3 expression was up-regulated in group HG+ H/R+ J ( P<0.05). Conclusion:Activation of Notch1/Hes1 signaling pathway is the endogenous protective mechanism of high glucose and H/R injury to cardiomyocytes.
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AIM: To investigate the role of transcription factor hairy and enhancer of split 1 (Hes1) in the malignant transformation of human bronchial epithelial cell line BEP2D induced by tobacco.METHODS: The BEP2D cells were chronically exposed to cigarette smoke condensate (CSC) at 1 cigarette per L until the 70th generation.The phenotype of malignant transformation of the cells induced by CSC was detected by soft agar clony formation assay.RT-PCR and Western blot were used to determined the expression of Hes1 at mRNA and protein levels in each generation of the cells.The proliferation and apoptosis of the BEP2D cells exposed to CSC were analyzed with the methods of MTT assay, flow cytometry and cell colony formation assay after treatment with Notch pathway bloker DAPT or liposome transfection with Hes1-siRNA.The expression of Hes1 in the peripheral small airway tissues of the smoking rats was evaluated by immunohistochemical staining.The expression of Hes1 in non-small-cell lung cancer and normal airway tissues was also detected by the methods of immunohistochemistry and RT-PCR.RESULTS: The BEP2D cells in the 70th generation had a malignant transformation phenotype.The expression of Hes1 in the BEP2D cells exposed to CSC for different time showed an increa-sing trend.DAPT and liposome transfection with Hes1-siRNA down-regulated the expression of Hes1, inhibited the cell proliferation and induced cell apoptosis.The expression of Hes1 in the airway mucosa of the rats exposed to cigarette smoke for 1 month and 6 months was significantly higher than that in control group.Cigarette smoking induced the expression of Hes1 in lung cancer and normal airway tissues.CONCLUSION: Hes1 may be involved in smoking-induced lung cancer by promoting the imbalance between apoptosis and proliferation.