BACKGROUNDClinical combination of some traditional Chinese medical herbs, including berberine, with irradiation is demonstrated to improve efficacy of tumor radiotherapy, yet the mechanisms for such effect remain largely unknown. The present study investigated the effect of berberine on apoptosis induced by X-rays irradiation and the relation between this effect and gap junction intercellular communication (GJIC).

METHODSThe role of gap junctions in the modulation of X-rays irradiation-induced apoptosis was explored by manipulation of connexin (Cx) expression, and gap junction function, using oleamide, a GJIC inhibitor, and berberine.

RESULTSIn transfected HeLa cells, Cx32 expression increased apoptosis induced by X-rays irradiation, while inhibition of gap junction by oleamide reduced the irradiation responses, indicating the dependence of X-rays irradiation-induced apoptosis on GJIC. Berberine, at the concentrations without cytotoxicity, enhanced apoptosis induced by irradiation only in the presence of functional gap junctions.

CONCLUSIONSThese results suggest that berberine potentizes cell apoptosis induced by X-rays irradiation, probably through enhancement of gap junction activity.

Apoptosis ; drug effects ; Berberine ; pharmacology ; Gap Junctions ; drug effects ; metabolism ; radiation effects ; HeLa Cells ; Humans ; Oleic Acids ; pharmacology ; X-Rays

We isolated three secondary metabolites by silica gel column chromatography from endophytic fungus 12.3.2 that was isolated from Taxus yunnanensis and could produce taxanes. They were identified as cembrene (3,7,11-trimethyl-14-(1-methylethyl)-1,3,6,10-cyclotetradecatetraene), diisooctyl phthalate (1,2-benzenedicarboxylic acid diisooctylester) and ethyl oleate (9-octadecenoic acid-ethyl ester) by infrared spectra (IR), mass spectra (MS) and 1H-nuclear magnetic resonance (NMR). Their antibacterial activities against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa and Candida albicans were examined. Results show that all of the three compounds could inhibit the growth of those pathogenic bacteria. Especially, cembrene showed stronger inhibition to S. aureus, B. subtilis and C. albicans. This is the first report on cembrene produced by plant endophytic fungus.
Anti-Bacterial Agents ; isolation & purification ; Diterpenes ; isolation & purification ; pharmacology ; Fungi ; metabolism ; Oleic Acids ; isolation & purification ; pharmacology ; Phthalic Acids ; isolation & purification ; pharmacology ; Taxus ; microbiology

OBJECTIVETo establish an in vitro cell model to investigate hepatic steatosis of non-alcoholic fatty liver disease.

METHODSHepG2 cells cultured in MEM containing 10 % fetal bovine serum were divided into control group and model group. At 7 0%-80 % confluency, HepG2 cells in model group were exposed to a long-chain mixture of free fatty acids (oleate and palmitate) for 24 h, cells in control group were subject to fresh medium. Lipid droplets were observed with oil red O stain and electron microscope, triglyceride and malonaldehyde were detected by respective assay kits.

RESULTA large number of lipid droplet were detected in model HepG2 cells; the level of triglyceride increased. However,malonaldehyde did not increase significantly compared with control group.

CONCLUSIONA large number of lipid droplet were detected in model HepG2 cells; the level of triglyceride increased. However, malonaldehyde did not increase significantly compared with control group.

Culture Media ; pharmacology ; Fatty Acids, Nonesterified ; pharmacology ; Fatty Liver ; Hep G2 Cells ; Humans ; Models, Biological ; Non-alcoholic Fatty Liver Disease ; Oleic Acid ; pharmacology ; Palmitates ; pharmacology

OBJECTIVETo determine the expression of connexin 43 (Cx43) protein and explore the functional modulation of gap junction intercellular communication in astrocytes.

METHODSCultured neonatal SD rat astrocytes were divided into normal control group, all-trans retinoic acid (ATRA) group (treated with 10 µmol/L ATRA for 24 h) and oleamide group (treated with 25 µmol/L oleamide for 2 h). Western blotting and immunofluorescence assay were used to detect total cellular Cx43 protein expression and Cx43 expression on the surface of the astrocytes, respectively. Parachute assay was used to evaluate the functional changes of gap junction intercellular communication of the astrocytes.

RESULTSCompared with the normal control cells, ATRA treatment resulted in a significantly increased expression of total Cx43 protein in the astrocytes (P<0.01), and oleamide significantly suppressed its expression (P<0.01). Similarly, ATRA obviously enhanced while oleamide suppressed Cx43 protein expression on the surface of the astrocytes. The gap junction intercellular communication of the astrocytes was enhanced by ATRA (P<0.01) and inhibited by oleamide (P<0.01).

CONCLUSIONATRA and oleamide can modulate gap junction intercellular communication of the astrocytes possibly by regulating the expression of Cx43 protein.

Animals ; Astrocytes ; metabolism ; Cell Communication ; drug effects ; Cells, Cultured ; Connexin 43 ; metabolism ; Gap Junctions ; metabolism ; Oleic Acids ; pharmacology ; Rats ; Rats, Sprague-Dawley ; Tretinoin ; pharmacology

To examine the role of glycogen synthase kinase 3 (GSK-3) in the apoptosis of pancreatic beta-cells to better understand the pathogenesis and to find new approach to the treatment of type 2 diabetes, apoptosis was induced by oleic acid (OA) in INS-1 cells and the activity of GSK-3 was inhibited by LiCl. The PI staining and flow cytometry were employed for the evaluation of apoptosis. The phosphorylation level of GSK-3 was detected by Western blotting. The results showed that OA at 0.4 mmol/L could cause conspicuous apoptosis of INS-1 cells and the activity of GSK-3 was significantly increased. After the treatment with 24 mmol/L of LiCl, a inhibitor of GSK-3, the OA-induced apoptosis of INS-1 cells was lessened and the phosphorylation of GSK-3 was increased remarkably. It is concluded that GSK-3 activation plays an important role in OA-induced apoptosis in pancreatic beta-cells and inhibition of the GSK-3 activity can effectively protect INS-1 cells from the OA-induced apoptosis. Our study provides a new experimental basis and target for the clinical treatment of type-2 diabetes.
Apoptosis/*drug effects ; Cell Line ; Fatty Acids, Nonesterified/*pharmacology ; Glycogen Synthase Kinase 3/*metabolism ; Insulin-Secreting Cells/*cytology ; Oleic Acid/pharmacology ; Phosphorylation

To observe a PPAR-alpha agonist effect of N-oleoylethanolamine (OEA) on CB2 (cannabinoid receptor 2), an anti-inflammatory receptor in vascular endothelial cell, healthy HUVECs and TNF-alpha induced HUVECs were used to establish a human vascular endothelial cell inflammatory model. Different doses of OEA (10, 50 and 100 micromol x L(-1)) had been given to HUVECs, cultured at 37 degrees C for 7 h and then collected the total protein and total mRNA. CB2 protein expression was detected by Western blotting and CB2 mRNA expression was assayed by real-time PCR. As the results shown, OEA (10 and 50 micromol x L(-1)) could induce the CB2 protein and mRNA expression, but not 100 micromol x L(-1). To detect if anti-inflammation effect of OEA is partly through CB2, CB2 inhibitor AM630 was used to inhibit HUVEC CB2 expression, then the VCAM-1 expression induced by TNF-alpha was detected, or THP-1 adhere to TNF-alpha induced HUVECs was examined. OEA (50 micromol x L(-1)) could inhibit TNF-alpha induced VCAM-1 expression and THP-1 adhere to HUVECs, these effects could be partly inhibited by a CB2 inhibitor AM630. The anti-inflammation effect of OEA is induced by PPAR-alpha and CB2, suggesting that CB2 signaling could be a target for anti-atherosclerosis, OEA have wide effect in anti-inflammation, it may have better therapeutic potential in anti-inflammation in HUVECs, thus achieving anti-atherosclerosis effect.
Anti-Inflammatory Agents ; pharmacology ; Atherosclerosis ; pathology ; Cell Adhesion ; drug effects ; Cells, Cultured ; Endocannabinoids ; pharmacology ; Endothelial Cells ; cytology ; metabolism ; Ethanolamines ; pharmacology ; Humans ; Indoles ; pharmacology ; Monocytes ; drug effects ; Oleic Acids ; pharmacology ; PPAR alpha ; antagonists & inhibitors ; RNA, Messenger ; metabolism ; Receptor, Cannabinoid, CB2 ; antagonists & inhibitors ; genetics ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology ; Vascular Cell Adhesion Molecule-1 ; metabolism

We investigated the mechanism of spontaneous cholesterol efflux induced by acyl-coenzyme A:cholesterol acyltransferase (ACAT) inhibition, and how an alteration of cholesterol metabolism in macrophages impacts on that in HepG2 cells. Oleic acid anilide (OAA), a known ACAT inhibitor reduced lipid storage substantially by promotion of cholesterol catabolism and repression of cholesteryl ester accumulation without further increase of cytotoxicity in acetylated low-density lipoprotein-loaded THP-1 macrophages. Analysis of expressed mRNA and protein revealed that cholesterol 7alpha-hydroxylase (CYP7A1), oxysterol 7alpha- hydroxylase (CYP7B1), and cholesterol 27-hydroxylase (CYP27) were highly induced by ACAT inhibition. The presence of a functional cytochrome P450 pathway was confirmed by quantification of the biliary cholesterol mass in cell monolayers and extracelluar medium. Notably, massively secreted biliary cholesterol from macrophages suppressed the expression of CYP7 proteins in a farnesoid X receptor (FXR)-dependent manner in HepG2 cells. The findings reported here provide new insight into mechanisms of spontaneous cholesterol efflux, and suggest that ACAT inhibition may stimulate cholesterol-catabolic (cytochrome P450) pathway in lesion-macrophages, in contrast, suppress it in hepatocyte via FXR induced by biliary cholesterol (BC).
Anilides/*pharmacology ; Bile/metabolism ; Cells, Cultured ; Cholesterol/*metabolism ; Cholesterol Esters/metabolism ; DNA-Binding Proteins/agonists/*metabolism ; Enzyme Inhibitors/pharmacology ; Gene Expression Regulation, Enzymologic/drug effects ; Hepatocytes/*drug effects/metabolism ; Humans ; Lipid Metabolism/drug effects/genetics ; Macrophages/*drug effects/metabolism ; Models, Biological ; Oleic Acids/*pharmacology ; Receptors, Cytoplasmic and Nuclear/agonists/*metabolism ; Sterol O-Acyltransferase/*antagonists & inhibitors/physiology ; Transcription Factors/agonists/*metabolism

The Escherichia coli fadR protein product, a paradigm/prototypical FadR regulator, positively regulates fabA and fabB, the two critical genes for unsaturated fatty acid (UFA) biosynthesis. However the scenario in the other Ɣ-proteobacteria, such as Shewanella with the marine origin, is unusual in that Rodionov and coworkers predicted that only fabA (not fabB) has a binding site for FadR protein. It raised the possibility of fad regulon contraction. Here we report that this is the case. Sequence alignment of the FadR homologs revealed that the N-terminal DNA-binding domain exhibited remarkable similarity, whereas the ligand-accepting motif at C-terminus is relatively-less conserved. The FadR homologue of S. oneidensis (referred to FadR_she) was over-expressed and purified to homogeneity. Integrative evidence obtained by FPLC (fast protein liquid chromatography) and chemical cross-linking analyses elucidated that FadR_she protein can dimerize in solution, whose identity was determined by MALDI-TOF-MS. In vitro data from electrophoretic mobility shift assays suggested that FadR_she is almost functionally-exchangeable/equivalent to E. coli FadR (FadR_ec) in the ability of binding the E. coli fabA (and fabB) promoters. In an agreement with that of E. coli fabA, S. oneidensis fabA promoter bound both FadR_she and FadR_ec, and was disassociated specifically with the FadR regulatory protein upon the addition of long-chain acyl-CoA thioesters. To monitor in vivo effect exerted by FadR on Shewanella fabA expression, the native promoter of S. oneidensis fabA was fused to a LacZ reporter gene to engineer a chromosome fabA-lacZ transcriptional fusion in E. coli. As anticipated, the removal of fadR gene gave about 2-fold decrement of Shewanella fabA expression by β-gal activity, which is almost identical to the inhibitory level by the addition of oleate. Therefore, we concluded that fabA is contracted to be the only one member of fad regulon in the context of fatty acid synthesis in the marine bacteria Shewanella genus.
Amino Acid Sequence ; Bacterial Proteins ; chemistry ; metabolism ; Base Sequence ; Binding Sites ; DNA, Bacterial ; metabolism ; Escherichia coli ; genetics ; metabolism ; Fatty Acid Synthase, Type II ; genetics ; metabolism ; Fatty Acids ; biosynthesis ; Gene Expression Regulation, Bacterial ; drug effects ; Molecular Sequence Data ; Oleic Acid ; pharmacology ; Protein Binding ; drug effects ; Regulon ; genetics ; Repressor Proteins ; chemistry ; metabolism ; Shewanella ; genetics ; metabolism