[Impact and mechanism of CHL1 in insulin resistant adipocytes and insulin resistant mouse model induced by high glucose and high fat].

Objective: To investigate the role and mechanism of cell adhesion molecule L1 like (CHL1) in insulin resistant adipocytes and insulin resistant mouse model induced by high glucose and high fat. Methods: The 3T3-L1 preadipocytes were randomly divided into control group (transfected with empty vector) and CHL1 overexpression group (transfected with CHL1 vector), cells were then induced to mature adipocytes by insulin, and insulin resistance was then induced by high sugar and high fat. The glucose content was measured to determine the glucose consumption of cells from the two groups. Protein expression levels of CHL1 and glucose transporter 4 (GLUT4), serine/threonine protein kinase (AKT) phosphorylation levels were detected by Western blot (WB), the mRNA expression levels of TNF-α and IL-6 were detected by real-time quantitative PCR (RT-qPCR). 24 C57BL/6 adult male mouse were randomly divided into conventional diet group (regular group), high-fat diet group (high-fat group), empty vector overexpression+high-fat group and CHL1 overexpression+high-fat group (n=6 each group). CHL1 overexpression was induced by tail vein injection of lentivirus. Four months later, mice were sacrificed, body weight was determined, and the epididymal white adipose tissue was collect. Hematoxylin-eosin staining (HE) was used to observe the pathology of mouse epididymal white adipose tissue, the expression of CHL1 was evaluated by immunohistochemical staining(IHC), RT-qPCR was used to detect the mRNA expression levels of CHL1, TNF-α and IL-6 in mouse epididymal white adipose tissue. Results: In vitro, glucose consumption was significantly higher in the CHL1 overexpression group than in the control group (P<0.05), and the protein expressions of CHL1 and GLUT4 were higher in the CHL1 overexpression group than those in the control group (P<0.01), and the mRNA expressions levels of TNF-α and IL-6 were lower in the CHL1 overexpression group than those in the control group (P<0.01). In vivo, the body weight and epididymal white adipose tissue of mouse were higher in the high-fat group and the empty vector overexpression+high-fat group than those in the conventional group (P<0.01), which were lower in the CHL1 overexpression+high fat group than in the empty vector overexpression+high fat group (P<0.01). HE results showed that the volume of epididymal white adipocytes was larger in the high-fat group and the overexpression control+high-fat group than that in the conventional group, which was smaller in the CHL1 overexpression+high fat group than in the empty vector overexpression+high fat group (P<0.01). The mRNA expression levels of IL-6 and TNF-α in epididymal white adipose tissue of mice were higher in the high-fat group and the empty vector overexpression+high-fat group than those in the conventional group (P<0.01), which were lower in the CHL1 overexpression+high fat group than in the empty vector overexpression+high fat group (P<0.05). IHC results showed that protein expression of CHL1 in epididymal white adipose tissue was lower in the high-fat group and the empty vector overexpression+high-fat group than in regular group, which was upregulated in the CHL1 overexpression+high fat group than in the empty vector overexpression+high-fat group (P<0.01). RT-qPCR results showed that mRNA expression of CHL1 in epididymal white adipose tissue was lower in the high-fat group and the empty vector overexpression+high-fat group than in regular group (P<0.01), which was higher in the CHL1 overexpression+high fat group than in the empty vector overexpression+high fat group (P<0.01). Conclusion: Overexpression of CHL1 can improve insulin resistance in adipocytes and mouse insulin resistance model induced by high glucose and high fat, and the beneficial effects might be mediated by the inhibition of AKT activation and the reduction of related inflammatory responses.

[Analysis of key genes and signal pathways of human papilloma virus-related head and neck squamous cell carcinoma].

Objective: To explore differentially expressed genes (DEG) and pathways between human papilloma virus (HPV) positive and negative head and neck squamous cell carcinoma (HNSCC) and to search gene targets for diagnosis and treatment of HPV-related HNSCC. Methods: HPV-related HNSCC expression profile chips of GSE3292 (including 8 HPV-positive and 28 HPV-negative HNSCC tissues, of which 15 collected from oral cavity cancer, 9 from oropharyngeal cancer, 9 from laryngeal cancer and 3 from hypopharyngeal cancer) were selected from Gene Expression Omnibus (GEO) database of National Center for Biotechnology Information and DEG were screened out using Gene-Cloud of Biotechnology Informs (GCBI). Gene ontology and pathway enrichment analysis were performed using DAVID and protein-to-protein interaction (PPI) network was constructed by STRING. Hub genes were identified by Cytoscape and then performed pathway enrichment analysis. Finally, expression differences of hub genes in the cancer genome atlas (TCGA) database were checked using UALCAN. Results: Five hundred and seventy-three DEG were screened out from more than 25 000 genes detected in the chips including 539 up-regulated genes and 34 down regulated ones. Twenty-seven hub genes including cyclin-dependent kinases 1(CDK1), proliferating cell nuclear antigen (PCNA), minichromosome maintenance proteins (MCM) family (MCM2, MCM3, MCM6 and MCM7), replication factor C subunit 4 (RFC4) and kinesin family member 11 (KIF11) were identified after two rounds of Cytoscape screening. Gene ontology and pathway analysis showed that DEG were mainly distributed in chromosome, nucleoplasm, nuclear lumen and membrane-enclosed lumen and participated in biological processes such as DNA replication, DNA metabolism, cell cycle and cell division, and also 6 major signaling pathways centered on p53 signaling pathway （P<0.01）. All hub genes were expressed differently between HPV-positive and negative HNSCC in TCGA database（P<0.01）. Conclusions: Hub genes including CDK1, PCNA, MCM family (MCM2, MCM3, MCM6 and MCM7) act as an important part on HPV-induced HNSCC and the p53 pathway is the key of this process and plays different regulatory roles between two subtypes of HNSCC. CDK1, MCM7 and RFC4 are expected to be potential treatment targets for HPV-positive HNSCC while MCM2, MCM3, PCNA and KIF11 may be employed as biomarkers for diagnosis and prognosis.

Biodegradation of nicotine from tobacco waste extract by Ochrobactrum intermedium DN2.

Ochrobactrum intermedium DN2 was used to degrade nicotine in tobacco waste extracts. The optimal temperature and pH of nicotine degradation by strain DN2 was 30-37 degrees C and 7.0, respectively. Under these optimal conditions, the average degradation rate of nicotine in a 30L fed-batch culture was 140.5 mg 1(-1) h(-1). The results of this study indicate that strain DN2 may be useful for reducing the nicotine content of reconstituted tobacco.

Sphingosine kinase 1 participates in insulin signalling and regulates glucose metabolism and homeostasis in KK/Ay diabetic mice.

AIMS/HYPOTHESIS: The aim of this study was to determine the potential role of sphingosine kinase 1 (SPHK1), a key sphingolipid metabolic enzyme, in glucose metabolism and homeostasis. METHODS: SMMC-7721 hepatoma cells and C2C12 myotube cells were used to explore the role of SPHK1 in glucose uptake in vitro. KK/Ay type 2 diabetic mice, which were transfected with adenovirus harbouring the human SPHK1 gene by i.v. injection, were used to investigate the glucose-lowering effects of SPHK1 in vivo. RESULTS: The basal glucose uptake and the insulin-stimulated glucose uptake in both 7721 cells and C2C12 cells were markedly enhanced when SPHK1 was overexpressed by adenovirus-mediated gene transfer, whereas they were substantially reduced when the expression of SPHK1 was inhibited or the activity of SPHK1 was blocked. Insulin could activate SPHK1 of both cell lines in a dose-dependent manner. SPHK1 gene delivery significantly reduced the blood glucose level of KK/Ay diabetic mice, but had no effect on that of normal animals. It also attenuated elevated levels of plasma insulin, NEFA, triacylglycerol, cholesterol and LDL, significantly ameliorated hyperglycaemia-induced injury of liver, heart and kidney, and enhanced phosphorylation of insulin-signalling kinases such as Akt and glycogen synthase kinase 3beta in livers of the diabetic animals. CONCLUSIONS/INTERPRETATION: SPHK1 is involved in insulin signalling and plays an important role in the regulation of glucose and fat metabolism; adenovirus-mediated SPHK1 gene transfer might provide a novel strategy in the treatment of type 2 diabetes mellitus.

Optimization of a medium for enhancing nicotine biodegradation by Ochrobactrum intermedium DN2.

AIMS: To optimize a medium for nicotine degradation by Ochrobactrum intermedium DN2 in presence of yeast extract, glucose and Tween 80 using response surface methodology (RSM). METHODS AND RESULTS: In this study, the effects of yeast extract, glucose and Tween 80 on nicotine degradation were investigated in flasks using a novel nicotine-degrading bacterium, O. intermedium DN2. A full factorial central composite design was applied in the design of experiments and in the analysis of the experimental data. The results showed that the most significant variable influencing nicotine degradation was yeast extract, followed by glucose, and then Tween 80. Moreover these three factors interacted with each other and combined to produce positive effects on nicotine degradation. The experimental data also allowed the development of an empirical model (P < 0.0001) describing the inter-relationship between independent and dependent variables. By solving the regression equation, the optimal values of the variables were determined as: yeast extracts 0.094%, glucose 0.101% and Tween 80 0.080%. Using the medium obtained, about 1,220 mg l(-1) of nicotine was degraded (95.55%) within 10 h at the specific biodegradation of 116.59 mg l(-1) h(-1) in 30-l bioreactor containing 25-l tobacco extract. CONCLUSIONS: An optimal medium of nicotine degradation by the strain DN2 was obtained. SIGNIFICANCE AND IMPACT OF THE STUDY: RSM proved to be reliable in developing the model, optimizing factors and analysing interaction effects. The results provide better understanding on the interactions between yeast extract, glucose and Tween 80 for nicotine biodegradation.

[Effects of fungal elicitor on cell status and taxol production in cells suspension cultures of Taxus chinesis var. mairei].

Effects of fungal elicitor on cell redox status and taxol production were studied in suspension cultures of Taxus chinesis var. mairei in the late exponential stage. The results show that fungal elicitor induced oxygen burst, changes of the cell redox status, alkalinization of medium and the fluctuation of the activity of redox enzymes with a sequence. The content of protein representing the quantity of enzymes increased. The activity of SOD increased quickly after treatment by fungal elicitor and that of POD could be kept at a higher level in contrast to the control. The activity of CAT was inhibited at first and followed by an obvious increase, while the activity of PAL was promoted. The taxol yield was 5 folds of the control, reaching to 67 mg/L.

[Study on the effects of salicylic acid on taxol biosynthesis].

The influence of salicylic acid on the production of taxanes in plant cell culture was studied. Experimental results showed that addition of salicylic acid at concentration of 0.1 mg/L could enhance the production of taxol to three-fold. The concentration of 10-DAB and baccatin III was also increasing while taxol concentration increases under salicylic acid elicitation. On the basis of the kinetic analysis about the simplified taxol biosynthesis pathway, a probable reason that salicylic acid improves the rate of 10-DAB producing reaction was introduced. The results above can direct its inducing mechanic research and provide the basis of multiple-elicitors synergism. The concentration of taxol arrives at 39 mg.L-1 induced by salicylic acid with silver nitrate, being 150 percent of the sum of taxol obtained under elicitation of salicylic acid and silver nitrate respectively.

[Study on taxol release in the two-liquid-phase cultures of Taxus cuspidata].

Effects of rare earth compound (ammonium sulphate), organic solvents(oleic acid and dibutylphthalate) and the integrated function of the rare earth compound and organic solvents were studied on taxol release in the Taxus cuspidata suspension cultures. And then effects of different organic solvents(paraffin, organic acid, alcohol and ester), their volumetric fraction and phase toxicity were studied on taxol release in the two-liquid-phase cultures of Taxus cuspidata. The results showed that the addition of the rare earth compound or the organic solvents could strengthen obviously taxol release, especially the organic solvents. But the addition of the rare earth compound could not strengthen further taxol release in the twoliquid-phase cultures of Taxus cuspidata. Therefore the organic solvents were very good permeabilizing reagents, which could enhance obviously secondary metabolite in the twoliquid-phase cultures of plant cells. Release percentage of taxol was increased into more than 75% from 40% of the control.