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BACKGROUND:High-methionine diet can cause liver injury in Cbs+/-mice,and hyperhomocystinemia is related to the occurrence and progression of various liver-related diseases,such as hepatic steatosis,autoimmune hepatitis,and alcoholic fatty liver disease.MicroRNAs(miRNAs)are involved in various cellular processes including cell survival,differentiation and autophagy,which are of great significance. OBJECTIVE:To investigate the critical role of miR-144-3p on Cbs+/-mouse hepatocyte autophagy induced by high methionine die. METHODS:(1)Ten male cystathione-β-synthase normal(Cbs+/+)mice and another 10 male mice with single gene knockout(Cbs+/-)of similar body mass,4 weeks of age,were fed a high-methionine diet and executed after 12 weeks to take liver tissue.(2)Human hepatocytes(HL-7702)were cultured in vitro and divided into control[0 μmol/L homocysteine(Hcy)],Hcy(100 μmol/L Hcy),mimic-NC(transfected with mimic-NC),mimic-NC + Hcy(mimic-NC transfecton+100 μmol/L Hcy),miR-144-3p mimic(transfected with miR-144-3p mimic),and miR-144-3p mimic + Hcy(miR-144-3p mimic transfection+100 μ mol/L Hcy),inhibitor-NC(transfected with inhibitor-NC),inhibitor-NC + Hcy(inhibitor-NC transfection + 100 μmol/L Hcy),miR-144-3p inhibitor(transfected with miR-144-3p inhibitor),and miR-144-3p inhibitor + Hcy(miR-144-3p inhibitor transfection + 100 μmol/L Hcy).Quantitative real-time PCR was used to detect the expression of miR-144-3p in liver tissue and hepatocytes.After transfection of miR-144-3p mimic or inhibitor,quantitative real-time PCR and western blot were used to detect the transfection efficiency of miR-144-3p and its effect on the expression of autophagy-related proteins LC3B and p62.The levels of alanine transferase and aspartate aminotransferase in hepatocyte supernatants were determined by enzyme linked immunosorbent assay.The correlation between the expression of miR-144-3 in hepatocyte and the levels of alanine transferase and aspartate aminotransferase in hepatocyte supernatants were analyzed by Pearson correlation analysis. RESULTS AND CONCLUSION:Compared with the Cbs+/+ group and control group,the expression of miR-144-3p in the liver tissue of the Cbs+/-group and in hepatocytes of the Hcy group was decreased(P<0.01).The expression of LC3B-Ⅱ/Ⅰ was decreased in hepatocyte after transfection of miR-144-3p mimic,while the protein expression of p62 was increased(P<0.01).The opposite results were obtained after transfection of miR-144-3p inhibitor(P<0.01).Compared with the mimic-NC group,the levels of alanine transferase and aspartate aminotransferase were decreased in the miR-144-3p mimic group(P<0.01),while the opposite results were obtained in the inhibitor-NC group(P<0.01).The expression of miR-144-3p in hepatocytes was negatively correlated with the levels of alanine transferase(P<0.01,r=-0.887 6)and aspartate aminotransferase(P<0.01,r=-0.829 9)in the supernatant of hepatocytes.To conclude,Hcy promotes hepatocyte autophagy by inhibiting the expression of miR-144-3p,which subsequently aggravates liver injury.
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BACKGROUND:Ischemic postconditioning is one of the effective ways to reduce ischemia-reperfusion injury and has been more and more widely used in clinical practice in recent years,but its specific molecular mechanism has yet to be studied. OBJECTIVE:To investigate the role and mechanism of piRNA-005854 in the aging cardiomyocytes caused by hypoxic postconditioning. METHODS:In vitro,cardiomyocytes were administered 8 mg/mL D-galactose for 9 days to induce their aging.β-Galactosidase staining was used to observe the aging of cardiomyocytes.Senescent cells were treated with hypoxia/reoxygenation and hypoxic postconditioning.ELISA was utilized to detect changes in myocardial injury markers creatine kinase isoenzyme MB and lactate dehydrogenase levels.Western blot assay was applied to detect the expression changes of autophagy-related proteins LC3II,p62,ULK1 and phosphorylated ULK1 in aging cardiomyocytes.qRT-PCR was employed to determine the expression level of piRNA-005854.piRNA-005854 inhibitor and piRNA-005854 mimics were transferred into aging cardiomyocytes and followed with hypoxic postconditioning.Western blot assay was used to examine the expression of LC3II,p62,ULK1 and phosphorylated ULK1. RESULTS AND CONCLUSION:(1)D-galactose induced obvious senescence of cardiomyocytes 9 days later.(2)Compared with the normoxia group,creatine kinase isoenzyme MB and lactate dehydrogenase levels increased in the hypoxia/reoxygenation group(P<0.01);LC3 II/I expression was increased;p62 expression was decreased;ULK1 phosphorylation level was increased,and piRNA-005854 expression was increased(P<0.01).(3)Compared with the hypoxia/reoxygenation group,creatine kinase isoenzyme MB and lactate dehydrogenase levels significantly reduced in the hypoxic postconditioning group(P<0.01);LC3 II/I expression significantly decreased(P<0.05);p62 expression increased(P<0.01);ULK1 phosphorylation level decreased(P<0.05),and piRNA-005854 expression decreased(P<0.01).(4)After transfection of piRNA-005854 inhibitor,LC3II/I expression was decreased(P<0.01);the expression of p62 was increased significantly(P<0.05);the phosphorylation level of ULK1 was decreased significantly(P<0.01).After transfection of piRNA-005854 mimics,LC3II/I expression was increased significantly;the expression of p62 was decreased,and the phosphorylation level of ULK1 was increased significantly(P<0.01).(5)The results show that piRNA-005854-mediated reduction of ULK1-dependent autophagy level is a possible mechanism that hypoxic postconditioning exerts its protective effect on aging cardiomyocytes.
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BACKGROUND:Increased homocysteine level induces apoptosis of human umbilical vein endothelial cells,but the mechanism remains unclear. OBJECTIVE:To investigate the role of hsa-circ-0001360 in human umbilical vein endothelial cell apoptosis induced by homocysteine. METHODS:In vitro cultured human umbilical vein endothelial cells were divided into control group,homocysteine group,interference control group,interference control + homocysteine group,hsa-circ-0001360 interference group,hsa-circ-0001360 + homocysteine interference group,overexpression control group,overexpression control + homocysteine group,hsa-circ-0001360 overexpression group and hsa-circ-0001360 + homocysteine overexpression group.All groups were treated with 100 μmol/L homocysteine.After 72 hours of intervention,the expressions of apoptosis-related proteins Bax,Bcl-2,and Caspase-3 were detected by western blot assay.The apoptotic rate was detected by flow cytometry.Quantitative real-time PCR was used to detect the expression of hsa-circ-0001360. RESULTS AND CONCLUSION:(1)Compared with the control group,the expression of Caspase-3 and Bax was significantly increased(P<0.01),and the expression of Bcl-2 was significantly decreased(P<0.01),and the apoptotic rate was significantly increased(P<0.01)in the homocysteine group.(2)Compared with control group,the expression of hsa-circ-0001360 was significantly increased in the homocysteine group(P<0.01).(3)The expression of hsa-circ-0001360 was significantly higher in the cytoplasm than that in the nucleus(P<0.01).(4)Compared with the interference control C group and interference control + homocysteine group,the expressions of Caspase-3 and Bax were significantly decreased(P<0.01),while the expression of Bcl-2 was significantly increased(P<0.01);the apoptotic rate was significantly decreased(P<0.01)in sh-hsa-circ-0001360 interference group and sh-hsa-circ-0001360 + homocysteine interference group.(5)Compared with overexpression control group and overexpression control + homocysteine group,the expressions of Caspase-3 and Bax were significantly increased(P<0.01),while the expression of Bcl-2 was significantly decreased(P<0.01);the apoptotic rate was significantly increased(P<0.01)in the hsa-circ-0001360 overexpression group and the hsa-circ-0001360 + homocysteine overexpression group.(6)In conclusion,hsa-circ-0001360 can promote the apoptosis of human umbilical vein endothelial cells induced by homocysteine.
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Homocysteine (Hcy) is an independent risk factor for cardiovascular disease, but the molecular mechanisms causing atherosclerosis in monocytes remain poorly characterized. The objective of the present study was to investigate the effects of Hcy on DNA methylation of PPARalpha,gamma and the underlying mechanism of PPARalpha,gamma expression that was induced by Hcy in monocytes. About 50, 100, 200, and 500 microM Hcy were added to the monocytes cultured for 48 h. PPARalpha,gamma that acted as lipid sensors and bind with mM affinities to ligands of antiatherosclerosis were determined by real-time reverse transcription-polymerase chain reaction and Western blotting in monocytes. Here, we used a high-throughput quantitative methylation assay that utilizes fluorescence-based real-time polymerase chain reaction to determine the levels of the PPARalpha,gamma DNA methylation. S-adenosylmethionine (SAM) level and S-adenosylhomocysteine (SAH) level were detected by high performance liquid chromatography. Results indicated that the levels of PPARalpha,gamma promoter methylation in monocytes cultured with Hcy were increased in comparison with the control group, and the peak was in the 100 muM Hcy group, however, a dose-dependent increase with increasing Hcy was not seen. Hcy also decreased mRNA and protein levels of PPARalpha,gamma in monocytes. Further, with the addition of Hcy, the levels of SAH were elevated, the levels of SAM and the ratio of SAM/SAH were lower, and the activity of C-5MT-ase was increased. In conclusion, these results suggest that PPARalpha,gamma DNA methylation induced by Hcy may represent an important mechanism to explain atherosclerosis, which may become a therapeutic target for preventing atherosclerosis induced by Hcy.