Inhibitory effect of schisandrin B on free fatty acid-induced steatosis in L-02 cells

AIM:To investigate the effects of schisandrin B (Sch B) on free fatty acid (FFA)-induced steatosis in L-02 cells.METHODS:Cellular steatosis was induced by incubating L-02 cells with a FFA mixture (oleate and palmitate at the ratio of 2:1) for 24 h.Cytotoxicity and apoptosis were evaluated by 3-(4,5-dmethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide assay and Annexin V/propidium iodide staining,respectively.Cellular total lipid was determined using a photocolorimetric method after Nile red staining,and triglyceride content was measured using an enzymatic kit.To study the effects of Sch B on steatosis,L-02 cells were treated with Sch B (1-100 μmol/L) in the absence or presence of 1 mmol/L FFA for 24 h,and cellular total lipid and triglyceride levels were measured.To explore the mechanisms of action of Sch B in the steatotic L-02 cells,mRNA levels of several regulators of hepatic lipid metabolism including adipose differentiation related protein (ADRP),sterol regulatory element binding protein 1 (SREBP-1),peroxisome proliferator-activated receptor (PPAR)-α and PPAR-γ were measured by quantitative real-time polymerase chain reaction (PCR),and protein levels of ADRP and SREBP-1 were measured by immunoblotting.RESULTS:Treatment with 1 mmol/L FFA for 24 h induced intracellular lipid accumulation in L-02 cells comparable to that in human steatotic livers without causing apparent apoptosis and cytotoxicity.Sch B mitigated cellular total lipid and triglyceride accumulations in the steatotic L-02 cells in a dose-dependent manner.Quantitative real-time PCR and Western blot analyses revealed that treatment of L-02 cells with 100 μmol/L Sch B reverted the FFA-stimulated up-regulation of ADRP and SREBP-1.CONCLUSION:Sch B inhibits FFA-induced steatosis in L-02 cells by,at least in part,reversing the up-regulation of ADRP and SREBP-1.

Herpes Simplex Virus 1 Infection Alters the mRNA Translation Processing in L-02 Cells

HSV-1 infection-mediated regulation of mRNA translation in host cells is a systematic and complicated process. Investigation of the details of this mechanism will facilitate understanding of biological variations in the viral replication process and host cells. In this study, a comparative proteomics technology platform was applied by two-dimension electrophoresis of HSV-1 infected normal human L-02 cell and control cell lysates. The observed protein spots were analyzed qualitatively and quantitatively by the PDQuest software package. A number of the different observed protein spots closely associated with cellular protein synthesis were identified by matrix-assisted laser-desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS). The expression levels of the RPLP1 protein, which is required for mRNA translation, and KHSRP protein, which is involved in rapid decay of mRNA, were up-regulated, whereas the expression level of RNP H2, which is involved in positive regulation on the mRNA splicing process, was down-regulated. All of these results suggest that HSV-1 infection can influence cellular protein synthesis via modulation of cellular regulatory proteins involved in RNA splicing, translation and decay, resulting in optimisation of viral protein synthesis when cellular protein synthesis is shut off. Although there is need for further investigations regarding the detailed mechanisms of cellular protein control, our studies provide new insight into the targeting of varied virus signaling pathways involved in host cellular protein synthesis.

Trichloroethylene Induces Biphasic Concentration-dependent Changes in Cell Proliferation and the Expression of SET-Associated Proteins in Human Hepatic L-02 Cells

Trichloroethylene （TCE） is a major pollutant that affects both occupational and general environments. The liver is an important target organ of TCEE. Substantial efforts and remarkable progress into understanding TCE cytotoxicity have been made in cultured liver cells. However, the molecular mechanisms by which TCE induces hepatotoxicity are not well understood. SET （also known as protein phosphatase 2A inhibitor, 12PP2A, or template-activating factor-I, TAF-D is a nuclear protein that regulates histone modification, gene transcription, DNA replication, nucleosome assembly,

Protection of Compatibility of Saikosapon d and Baicalin on Carbon Tetrachloride Injured L-02 Cells Based on TLR4-NFκB Signaling Pathway

[Objectives] To study the protection of compatibility of Saikosapon d and Baicalin on carbon tetrachloride( CCl_4) injured L-02 cells. [Methods] Normal human hepatocyte cell line L-02 cells were cultured in vitro,and CCl_4 was used to induce hepatocellular injury. Interventions were carried out with Saikosaponin d and Baicalin at different dosage. The proliferation of L-02 cells in each group was determined by methylthiazolyl tetrazolium( MTT) assay; the levels of AST and ALT in the culture supernatants were detected by enzyme-linked immunosorbent assay( ELISA); the expressions of TLR4 and NFκBp65 proteins in each group were determined by immunohistochemistry.[Results] In the CCl_4 injured group,the proliferation of L-02 cells was significantly declined,the levels of AST and ALT in cell culture medium were significantly increased,and the expressions of TLR4 and NFκBp65 in L-02 cells were increased; after the intervention of Saikosaponin d and Baicalin,1. 75 μg/mL group and 1. 5 μg/mL group had an effect of promoting the proliferation of L-02 cells and could reduce the levels of AST and ALT in the cell culture medium,and TLR4 and NFκBp65 proteins in L-02 cells also had a certain inhibitory effect. [Conclusions] The compatibility of Saikosapon d and Baicalin has a certain protective effect on CCl_4 injured L-02 cells. The protection mechanism may be related with its down-regulating TLR4-NFκB signaling pathway and reducing the inflammation.

Effects of sodium arsenite on the expression of microRNA-191 and tissue inhibitor of metalloproteinase 3 in L-02 cells

Objective To investigate the effects of sodium arsenite（NaAsO2）on the expression of microRNA-191（miR-191）and tissue inhibitor of metalloproteinase 3（TIMP-3）in human normal hepatic cells（L-02 cells）.Methods L-02 cells were exposed to different doses of Na2As O2[0（control group）,5,25,50 and 75μmol/L]