Objective To observe the effect of human umbilical cord-derived mesenchymal stem cells (hMSCs) on type 2 diabetic rats, and to explore the possible mechanism. Methods Type 2 diabetic rats were induced by high-fat diet combined with a low dosage of streptozotocin ( STZ, 25 mg/ kg). After 3 × 106 hMSCs suspended in 1 ml PBS or 1ml 10-fold concentrated hMSC supernatant were intravenously infused into the rats via the tail vein, the blood glucose levels were measured every day. One week later, intraperitoneal glucose tolerance test and insulin tolerance test were performed to evaluate the effects of hMSCs on diabetic rats. Pancreatic tissues were collected for insulin/ glucagon immunofluorescence staining. Results After hMSCs infusion, blood glucose level and homeostasis model of assessment for insulin resistance index were significantly decreased in type 2 diabetic rats(both P<0. 01). The glucose tolerance and insulin tolerance were greatly alleviated by hMSCs(all P<0. 01). Intravenously infused 1ml 10-fold concentrated hMSC supernatant showed a similar result to hMSCs. Conclusion In type 2 diabetic rats, hMSCs are able to effectively lower the blood glucose level, improve insulin sensitivity, and increase the number of β cells, which seems to be mediated by their secreted molecules.

Objective:To prepare Streptococcus pneumonia type 3 capsular polysaccharide conjugate vaccine.Methods:Strep-tococcus pneumonia type 3 capsular polysaccharide was covalently linked to protein CRM197 and its immunogenicity was evaluated in infant mice.Results:Through the preliminary research, we found that the polysaccharide was treated with 0.2 mol/L acetic acid at 85℃ for 1 h,activation grade reached to 10.0,and the radio of polysaccharide and protein was 20∶10,could induce infant mice to produce the high titers of antibodies.Conclusion:This result shows that conjugate vaccine prepared under this condition retained intact antigenicity.It is applicable to prepare Streptococcus pneumonia type 3 capsular polysaccharide conjugate vaccine by the process condi-tions.

In order to establish an efficient and low-cost production procedure of recombinant glycerol kinase (r-GK), we expressed the r-GK gene at high level in E. coli by induction with lactose on a large-scale fermentation of 300L. The results showed that the biomass concentration reached OD600 of 42 and the expression of r-GK in E. coli accounted for about 30% of total soluble protein. The cell-free extract was processed by selective thermo-denaturation and then purified with Ni sepharose FF column chromatography. Finally, highly purified r-GK was obtained and its purity reached 97% by using analysis on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), polyacrylamide gel electrophoresis (PAGE) and gradient polyacrylamide gel electrophoresis (Gradient PAGE). Further identification study showed that the molecular weight of r-GK was 120kDa with two subunit of 58kDa. Contaminants of NADH oxidase and catalase were not detected in the sample pool of r-GK. The purified r-GK was able to retain about 85% of its initial activity at 4 degrees C for 30 days. After lyophilized, it can retain 93% of its initial activity at 4 degrees C for one year.
Escherichia coli ; genetics ; metabolism ; Fermentation ; Glycerol Kinase ; biosynthesis ; genetics ; isolation & purification ; Recombinant Proteins ; biosynthesis ; genetics ; isolation & purification

BACKGROUNDProstate specific membrane antigen (PSMA) can facilitate the growth, migration, and invasion of the LNCaP prostate cancer cell lines, but the underlying molecular mechanisms have not yet been clearly defined. Here, we investigated whether PSMA serves as a novel regulator of the phosphatidylinositol 3-kinase (PI3K)/Akt signaling by employing PSMA knockdown model and PI3K pharmacological inhibitor (LY294002) in LNCaP prostate cancer cells.

METHODSPSMA knockdown had been stably established by transfecting with lentivirus-mediated siRNA in our previous study. Then, LNCaP cells were divided into interference, non-interference, and blank groups. We first testified the efficacy of PSMA knockdown in our LNCaP cell line. Then, we compared the expression of PSMA and total/activated Akt by Western blotting in the above three groups with or without LY294002 treatment. Furthermore, immunocytochemistry was performed to confirm the changes of activated Akt (p-Akt, Ser473) in groups. Besides, cell proliferation, migration, and cell cycle were measured by CCK-8 assay, Transwell analysis, and Flow cytometry respectively.

RESULTSAfter PSMA knockdown, the level of p-Akt (Ser473) but not of total-Akt (Akt1/2) was significantly decreased when compared with the non-interference and blank groups. However, LY294002 administration significantly reduced the expression of p-Akt (Ser473) in all the three groups. The results of immunocytochemistry further confirmed that PSMA knockdown or LY294002 treatment was associated with p-Akt (Ser473) down-regulation. Decrease of cell proliferation, migration, and survival were also observed upon PSMA knockdown and LY294002 treatment.

CONCLUSIONSTaken together, our results reveal that PI3K/Akt signaling pathway inhibition may serve as a novel molecular mechanism in LNCaP prostate cancer cells of PSMA knockdown and suggest that Akt (Ser473) may play a critical role as a downstream signaling target effector of PSMA in this cellular model.

Antigens, Surface ; genetics ; metabolism ; Cell Line, Tumor ; Glutamate Carboxypeptidase II ; genetics ; metabolism ; Humans ; Male ; Phosphatidylinositol 3-Kinases ; metabolism ; Prostatic Neoplasms ; enzymology ; genetics ; therapy ; Proto-Oncogene Proteins c-akt ; metabolism ; RNA Interference ; Signal Transduction ; genetics ; physiology