Abnormal liver regeneration of T-cell-deficient mice after partial hepatectomy / 军事医学

Objective To investigate the regulation of T cells in the process of liver regeneration using a model of mice after 70% liver resection.Methods We performed 70% hepatectomy in T-cell-deficient mice and control mice.The liver mass and body mass ratio, BrdU infiltration level, proliferating cell nuclear antigen (PCNA),expression of M phase marker protein p-HDAC3, and serum transaminase levels were measured.Results The recovery of liver mass and body mass ratio of thymus-deficient mice occurred significantly later than that of control mice.The peak time of BrdU infiltration levels and the expression of PCNA and p-HDAC3 in T-cell-deficient mice were later than in control mice, but the degree of liver injury was lower.Conclusion T cells are involved in the regulation of liver regeneration, and the absence of T cells delays the process of liver regeneration.

Effect of tyrosine metabolites on cell proliferation,cell cycle and chemosensitivity of lung cancer cells / 军事医学

Objective To investigate the effects of four tyrosine metabolites on the proliferation, cell cycle and chemosensitivity of lung cancer cells.Methods A549 cells were cultured with different concentrations of tyrosine metabolites:tyrosine, 4-hydroxyphenylpyruvate(HPPA), homogentisic acid(HGA) and fumaric acid (FA) in vitro.High content imaging analysis system was used to monitor cell proliferation.Flow cytometry was used to detect cell cycle and apoptosis.Protein and mRNA level of Bax and Bcl-2 were measured by Western blot.Results Tyrosine metabolites had no effect on cell cycle and proliferation of A549 cells.HGA decreased the cell apoptosis of A549 cells induced by Gefitinib with depressed Bax expression and elevated Bcl-2 expression.However, FA increased the apoptosis of A549 cells induced by Gefitinib with up-regulation of Bax and down-regulation of Bcl-2.No obvious effect of tyrosine and HPPA was detected on Gefitinib induced cell apoptosis.Conclusion HGA and FA may play an important role in drug sensitivity of lung cancer cells, indicating a critical role of tyrosine metabolism in lung cancer.

Response of EDAG knockout mice to low-dose radiation-induced damage / 军事医学

Objective To generate the erythroid differentiation associated gene(EDAG) knockout mice and analyze their sensitivity to low dose radiation-induced damage.Methods Zinc finger nuclease technology ( ZFNs ) was used to produce the EDAG knockout mice.The low dose radiation-induced damage was evaluated by peripheral blood cell counts, DNA damage and colony formation of bone marrow cells.Wild-type and EDAG knockout mice were irradiated with 0.31 Gy/min X-ray, one minute per day for seven consecutive days, and the cumulative radiation dose was 2.17 Gy(n=7).The blood cell counts were measured by an automated hemocytometer.DNA damage was detected by immunofluorescence assay with a DNA damage marker p-H2A.x antibody (n=3).The colony formation ability of bone marrow cells was evaluated with a semi-solid culture medium(n=3).Results A model of EDAG knockout mice was established.Compared to wide type mice, white blood cell counts of EDAG knockout mice decreased significantly while the DNA damage marker p-H2A.x expression was increased on the third day after X-ray irradiation.The ability of colony-forming was reduced after 7 days of X-ray irradiation.Conclusion Our present study found that EDAG knockout mice are more sensitive to low dose radiation-induced damage as shown by decreased peripheral blood cells counts, reduced colony-forming ability of bone marrow cells, and increased DNA damage.These results suggest that EDAG knockout mice can serve as a powerful tool for evaluation of the biological effects of low-dose radiation damage.

Construction a lentiviral vector for RNA interference of glutathione peroxidase 2 gene and its effect on HepG2 cell apoptosis / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a RNA interference lentiviral vector for human glutathione peroxidase 2 (GPX2) gene and observe the effect of GPX2 knockdown on cell apoptosis.</p><p><b>METHODS</b>The sequence of the small interfering RNA (siRNA) for GPX2 interference was inserted into the pSicoR vector. HepG2 cells were infected by the packaged si-GPX2 lentivirus and the expression of GPX2 in the infected cells was detected by both RT-PCR and Western blotting. Changes of cell apoptosis following the infection were analyzed by flow cytometry.</p><p><b>RESULTS</b>The lentiviral particles pSicoR-GPX2 were successfully packaged. The expression of GPX2 in the infected cells was obviously down-regulated at both RNA and protein levels. GPX2 knockdown caused increased apoptosis rate, increased Bax expression and lowered Bcl-2 expression in HepG2 cells.</p><p><b>CONCLUSION</b>We have successfully constructed the lentiviral vector for RNA interference of human GPX2 gene.</p>

Hepassocin (HPS)-a new serum biomarker of liver injury in mice / 军事医学

Objective Acute liver failure is one of the significant causes of death clinically.It is important to explore new serum markers of liver injury for early diagnosis and prognosis prediction of severe liver disease.Hepassocin ( HPS) is a liver-specific mitogenic growth factor.Our study is intended to investigate the correlation between HPS serum levels and the degree of liver injury.Methods Firstly, a mouse model of acute liver injury was constructed via intraperitoneally injection with different doses of CCl4 .Then the survival rate, alanine aminotransferase ( ALT) , aspartate aminotransferase ( AST) and the pathological changes in the liver were detected.Meanwhile, ELISA assay was performed to detect the serum level of HPS.In addition, the mRNA level and protein level of HPS were detected by real-time PCR and Western blotting, respectively.Results The mortality rate was increased and the liver damage was aggravated with the increase of the CCl4 dose.Besides, the ALT and AST levels were also increased in a dose-dependent manner.Additionally, the mRNA and protein levels of HPS were significantly up-regulated and closely related to the degree of the liver injury in the model. Conclusion HPS can be used as a new marker of liver injury in mice.

Effect of ribosomal protein S3 Ser209 on NF-κB transcriptional activity and its DNA binding capacity / 军事医学

Objective To construct expression vectors of human ribosomal protein S 3(RPS3) and RPS3Ser209 mutant in orcler to investigate the effect of RPS3Ser209 mutant on NF-κB signaling pathway and DNA binding capacity .Methods The vector RPS3-myc was amplified by polymerase chain reaction ( PCR) from the human liver cDNA and subcloned into pcDNA-3.1myc-HisB.RPS3S209A represented mutant RPS3 expression vectors, in which the designated amino acid was mutated to an alanine residue .Dual luciferase reporter gene assay was used to detect the NF-κB transcription activity in HEK293 cells,immunofluorescence to detect RPS3 location, and EMSA to examine NF-κB DNA-binding activity.Results The expression vectors of RPS3-myc and RPS3S209A-myc were constructed.Compared with wild-type RPS3,the nucleus translocation, transactivation activity of NF-κB and DNA binding ability of RPS3S290A were reduced significantly .Conclu-sion The impact of RPS3 on NF-κB signaling pathway depend on its serine 209.

Lentivirus-mediated interference of E3 ubiquitin ligase RNF31 inhibits tumor-necrosis factor-α-induced activation of nuclear factor-κB pathway / 南方医科大学学报

<p><b>OBJECTIVE</b>To study the effect of E3 ubiquitin ligase RNF31 knockdown on nuclear factor-κB (NF-κB) pathway activation and cell apoptosis.</p><p><b>METHODS</b>Human RNF31 siRNA sequences were cloned into the lentiviral vector pGreenPuro and transiently transfected in HEK293T cells to screen the most effective fragments, which were co-transfected along with the packaging plasmids PMD and SPA in 293T cells. The cell supernatant was collected at 24 h and 48 h after the transfection and the viral titers were determined with flow cytometry. Real-time PCR and Western blotting were used to evaluate the effect of RNF31 knockdown on the expression of NF-κB downstream target genes and IκBα activity; the changes of NF-κB pathway transcriptional activity were assessed with dual luciferase reporter gene. Hochest dying was used to examine the influence of RNF31 down-regulation on cell apoptosis.</p><p><b>RESULTS</b>RNF31 knockdown mediated by the lentiviral vector pGreenPuro-RNF31 suppressed the transcriptional activity of NF-κB and the downstream target genes in HEK293 cells stimulated with TNF-α. RNF31 knockdown also resulted in suppression of NF-κB-stimulated expression of pIκBα and in increased apoptosis of cells stimulated with TNF-α for 24 h.</p><p><b>CONCLUSION</b>RNF31 down-regulation inhibits NF-κB pathway activation induced by TNF-α.</p>

NLK negatively regulate TGFβsignaling pathway via Smad4 / 重庆医学

Objective To study the effect of NLK on TGFβsignaling pathway and explore the molecular mechanism .Methods Protein stability assay was used to determine the influence of NLK on the degradation of Smad 4 .In vivo ubiquitination assay was applied to detect the effect of NLK on the ubiquitination of Smad4 .Luciferase reporter gene assay was used to detect the effect of NLK on CAGA‐luc and 3TP‐luc ,the responsive reporter of TGFβ signaling pathway .Real time PCR was applied to examine the effect of NLK on the expression of p21 and PAI‐1 ,the target genes of TGFβsignaling pathway .Results In HEK293T cell ,over ex‐pression of NLK promotes the degradation and ubiquitination of Smad4 .In HEK293T cells ,Ectopic expression of NLK inhibits the activity of CAGA luc and 3TP luc stimulated by TGFβ.In HepG2 cells ,over expression of NLK inhibits the expression of p21 and PAI 1 ,the target genes of TGFβsignaling pathway .Conclusion NLK promotes the ubiquitination and degradation of Smad4 ,conse‐quently inhibits TGFβsignaling pathway .

Construction of a GFP/Puro double-labeled lentiviral vector containing CK8 interfering RNA and its effect on cell apoptosis in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a GFP/Puro double-labeled lentiviral expression vector for CK8 silencing and assess the effects of CK8 silencing on cell apoptosis.</p><p><b>METHODS</b>The siRNA sequences of CK8 were inserted into the lentiviral expression vector GV248 and transfected into 293T cells with the packaging plasmids PMD and SPA. The lentivirus was collected at 24 and 36 h post-transfection. Flow cytometry was used to detect the virus titer and the positive cells were selected with puromycin. The knockdown of CK8 was examined by Western blotting. The effect of CK8 down-regulation on cell apoptosis induced by cisplatin was detected with Annexin V/PI staining.</p><p><b>RESULTS AND CONCLUSION</b>We successfully constructed CK8 interference lentiviral vector and obtained a stable cell line with CK8 knock-down that was sensitive to cisplatin-induced apoptosis.</p>

Construction of a lentiviral vector for RNA interference of glycerol kinase gene in human hepatocytes in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To construct a lentiviral vector for RNA interference (RNAi) of human glycerol kinase (GK) gene to stably down-regulate GK expression in human hepatocytes.</p><p><b>METHODS</b>The sequence of siRNA for GK interference were cloned into the pSicoR vector. Following packaging in 293T cells, the lentivirus was titrated using fluorescence activated cell sorting. Human hepatocyte L02 cells was infected with the lentivirus and the expression of GK was analyzed using Western blotting.</p><p><b>RESULTS</b>The lentiviral particle pSicoR-GK was successfully packaged with a virus titer reaching 3×10(7) pfu/ml. The expression level of GK protein was down-regulated to 20% of the control level in L02 cells infected with the lentivirus.</p><p><b>CONCLUSION</b>The lentiviral vector for RNAi of human GK gene has been successfully constructed, which can significantly down-regulate GK expression in human hepatocytes.</p>