BACKGROUND: Bone marrow mesenchymal stem cells (BMSCs) and BMSCs-derived exosomes have similar functions, but the regulatory mechanism underlying the release of exosomes is still unclear. OBJECTIVE: To investigate the role of GW4869, an inhibition of neutral sphingomyelinase 2, in the release of exosomes in BMSCs and the influence of GW4869 on BMSCs proliferation. METHODS: Rat BMSCs were divided into three groups: normal control group, 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (24-hour GW4869 treatment followed by 24-hour successive culture with drug withdrawal). Cultured cells were collected to extract exosomes by ultracentrifugation. Western blot was used to detect exosome-associated proteins CD63 and tumor susceptibility gene 101 (TSG101). The concentration and size distribution of exosomes were measured using nanoparticle tracking analysis. BCA was used to test the level of total proteins in exosomes. Live cell imaging system was used to observe the influence of GW4869 on BMSCs proliferation. RESULTS AND CONCLUSION: (1) Western blot results showed that exosomes expressed marker proteins such as CD63, TSG101. (2) Findings from the nanoparticle tracking analysis confirmed that the size of released exosomes was about 114 nm. (3) Significantly reduced release of exosomes was found in the two treatment groups compared with the normal control group (P < 0.01), but there was no significant difference between 24-hour GW4869 treatment group and withdrawal of GW4869 for 24 hours group (P > 0.05). (4) No significant difference in the proliferation of BMSCs was found among the three groups (P > 0.05). To conclude, 24-hour W4869 can inhibit the release of exosomes by BMSCs and this inhibitory effect is still sustained within 24 hours after drug withdrawal. However, GW4869 has no influence on the proliferation of BMSCs.

Objective To elucidate the genetic diversifications of avian influenza subtype H5N1 viruses in the boundary regions of Yunnan province during 2009 to July,2011.Methods Swab samples were collected from foreign poultry and wild birds in boundary regions of Yunnan province during 2009 to July,2011 and tested by H5/N1 subtype-specific multiplex RT-PCR.The HA genes of H5N1 virus from the positive samples were amplified by RT-PCR and cloned into pMD 18-T vectors for sequencing.Both alignment and phylogenetic analysis were performed with sequences of the known reference strains.Results Fifteen different HA sequences were obtained from 36 representative positive samples and could be divided into 2 distinct Clades (2.3.2 and 2.3.4).Through phylogenetic analysis,Clade 2.3.2 and 2.3.4 could then be further divided into 3 ( Ⅱ -1 to Ⅱ -3 ) and 2 smaller clades ( Ⅰ -1 and Ⅰ -2),respectively.The viruses of Clade 2.3.2 Ⅱ -1 and Ⅱ-2 were new variant strains of H5N 1 virus.The cleavage sites of HA from positive samples all possessed molecular characterization of highly pathogenic avian influenza virus.Mutation of key amino acids had been found among receptor binding sites,potential glycosylation sites,neutralizing epitopes and others.Conclusion It seemed evident that the H5N1 subtype viruses showed genetic diversifications and had undergone the evolution progress of multi-clade (2.3.2,2.3.4) to single caide (2.3.2) in the boundary regions of Yunnan province,during 2009 to July,2011.

OBJECTIVE: To investigate the effects of di-( 2-ethylhexyl) phthalate( DEHP) on the expression of the key genes involved in glucose and lipid metabolism,and explore the toxicity of DEHP on the glucose and lipid metabolism in HepG2 cells cultured in vitro. METHODS: HepG2 cells in logarithmic growth phase were divided into DEHP exposure group and control group. The exposure group was exposed to DEHP with different final concentrations( 5,10,50,100,500 and1 000 μmol / L),and the control group was exposed to dimethyl sulfoxide of corresponding concentrations. After 24 hours of DEHP exposure,real-time fluorescence quantitative polymerase chain reaction( Q-PCR) was applied to detect the level of mRNA transcription of peroxisome proliferators-activated receptor α( PPARα), which is an endogenous marker indicating the success of DEHP exposure. In addition,the level of mRNA transcription of key genes involved in glucose and lipid metabolism were also measured by Q-PCR,including glucose-6-phosphatase( G-6-Pase),phosphoenolpyruvate carboxykinase( PEPCK),stearoyl-coenzyme A desaturase 1( SCD1),fatty acid synthase,sterol regulatory elementbinding protein 1c and acetyl Co A carboxylase 1. P ≤0. 008 was considered as statistical significance. RESULTS: After DEHP exposure,the mRNA transcription level of PPARα was significantly elevated in all exposure groups( P < 0. 008)except for 5 μmol / L DEHP exposure group,which indicated the successful establishment of DEHP exposure model. The mRNA transcription level of G-6-Pase was significantly increased in 100 and 500 μmol / L DEHP exposure groups( P ≤0. 008) when compared with the controls; the PEPCK mRNA transcription level of showed no significant differences between the 6 DEHP exposure groups and their corresponding control groups( P > 0. 008). The mRNA transcription level of SCD1 was significantly down-regulated in 100 μmol / L DEHP exposure group( P < 0. 008) when compared with its control. The mRNA transcription level of other key genes involved in the lipid metabolism were not significantly altered after DEHP exposure( P > 0. 008). CONCLUSION: The effect of DEHP on glucose metabolism was mainly manifested by promoting G-6-Pase gene expression,which is the rate-limiting enzyme for gluconeogenesis. The effect of DEHP on the lipid metabolism of HepG2 cells was limited.