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Objective ::To investigate the role of trehalose in hepatic ischemia-reperfusion injury and its underlying mechanisms.Methods:C57BL/6J mice were randomly divided into no-ischemia group, ischemia-reperfusion group, trehalose-treated group and normal saline control group. After ischemia for 90 minutes, reperfusion immediately or 6h, blood and liver tissues were collected, and serum was separated. The liver function parameters of ALT, AST, the inflammatory factors of TNF-α, IL-1β and IL-2, and the pathological changes of liver were detected to study the role of trehalose during hepatic ischemia-reperfusion injury. Hypoxia-reoxygenation cell model was established by AML12 mouse hepatocyte line, and divided into experimental group and control group. The experimental group was divided into low dose group and high dose group according to the concentration of trehalose administrated. And the control group had no use of trehalose. The level of apoptosis was measured to study the effect of trehalose on apoptosis induced by hepatic ischemia-reperfusion injury with flow cytometry. Western blot was utilized for detecting the levels of Caspase-3, Cleaved Caspase-3 and Bcl-2 protein to understand the molecular mechanisms of trehalose in apoptosis during hepatic ischemia-reperfusion injury.Results:In vivo animal experiments showed that liver function and such inflammatory factors as ALT, AST, TNF-α, IL-1β and IL-2 increased in ischemia-reperfusion group after hepatic ischemia-reperfusion ( P<0.05), and liver tissue became necrotic. After a treatment of trehalose, the levels of ALT, AST, TNF-α, IL-1β and IL-2 were lower than those of normalsaline control group and the area of liver tissue necrosis also decreased ( P<0.05). In vitro cell experiments showed that the apoptosis level of hepatocytes in the experimental group decreased compared with the control group.And the level of activated pro-apoptotic protein Cleaved Caspase-3 decreased, the level of anti-apoptotic protein Bcl-2 increased. Conclusions:Trehalose has protective effects on hepatic ischemia-reperfusion injury in vivo and in vitro. The mechanism may be involved in inhibiting inflammation induced by hepatic ischemia-reperfusion injury, suppressing the activation of Caspase-3 and promoting the expression of Bcl-2, thus played a protective role by extenuation of hepatocyteapoptosis.
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Objective To establish a mouse model of hepatocyte-specific TM6SF2 knockout, and to investigate the role of TM6SF2 in the development of nonalcoholic fatty liver disease (NAFLD). Methods The CRISPR/Cas9 technique and the Cre/LoxP strategy were used to establish a stable mouse model of hepatocyte-specific TM6SF2 knockout. The mice with hepatocyte-specific TM6SF2 knockout and the control mice were given a normal diet or a high-fat diet (HFD) for 16 weeks, and related indices were measured, including general status (body weight and liver weight), glucose metabolic indices (fasting blood glucose and insulin), and lipid metabolism (plasma triglyceride, cholesterol, and liver triglyceride). The t -test was used for comparison of normally distributed continuous data between two groups. Results Under the condition of HFD, compared with the control mice, the mice with hepatocyte-specific TM6SF2 knockout had significantly higher liver weight (2.235±0.175 g vs 1.258±0.106 g, t =4.789, P 0.05). Under the condition of HFD, there were no significant differences in the levels of plasma triglyceride and cholesterol between the mice with hepatocyte-specific TM6SF2 knockout and the control group ( P > 0.05), while the mice with hepatocyte-specific TM6SF2 knockout had a significant increase in the level of liver triglyceride compared with the control mice (23.969±0.978 mg/g vs 18.229±1.633 mg/g, t =3.015, P =0.024). Conclusion Hepatocyte-specific knockout of TM6SF2 can aggravate liver lipid accumulation and liver injury in mice with NAFLD.
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<p><b>OBJECTIVE</b>To investigate the mechanisms by which retinoic acid-induced gene G (RIG-G) protein regulates p21 gene expression.</p><p><b>METHODS</b>Western blot was used to detect the effects of RIG-G protein overexpression on p21 protein expression level in leukemia cell line NB4 cells and the phosphorylation of both c-Jun and JNK in U937 cells. The c-Jun expression plasmid and p21 gene promoter-containing reporter plasmid were co-transfected into 293T cells, to explore the regulatory effect of c-Jun protein on p21 gene expression by luciferase reporter assay.</p><p><b>RESULTS</b>Western blot showed that the overexpression of RIG-G protein significantly upregulated p21 protein level in the NB4 cells, and the level of p21 protein largely increased along with the induction of endogenous RIG-G protein during the differentiation of NB4 cells treated by all-trans retinoic acid (ATRA). Moreover, the phosphorylation of both c-Jun and JNK decreased in RIG-G-overexpressing U937 cells while total c-Jun and JNK proteins remained unchanged. After using the JNK inhibitor SP600125 to block JNK phosphorylation, the level of c-Jun phosphorylation was still dramatically reduced in the RIG-G-overexpressing U937T-RIG-G cells, compared with the control U937T-pTRE cells. These results indicated that the inhibitory effect of Rig-G protein on c-Jun phosphorylation could not only be through the JNK pathway, but also via some JNK-independent pathways. Luciferase reporter assay showed that when 0.1, 0.5, 1.0 and 2.0 µg c-Jun-expressing plasmids were respectively transfected into 293T cells, compared with the empty vector-transfected group, the relative luciferase activities were (83.0 ± 1.7)%, (73.7 ± 0.7)%, (68.9 ± 0.9)% and (64.1 ± 0.9)%, indicating that the transcriptional activity of p21 gene could be inhibited by c-Jun protein.</p><p><b>CONCLUSIONS</b>RIG-G protein may suppress the phosphorylation of c-Jun protein through different signal pathways, thereby increasing the expression of p21 gene, arresting the cell cycle and inhibiting the cell growth in U937 cells.</p>