Neonatal cortical astrocytes possess intrinsic potential in neuronal conversion in defined media.

Astrocytes are multifunctional brain cells responsible for maintaining the health and function of the central nervous system. Accumulating evidence suggests that astrocytes might be complementary source across different brain regions to supply new neurons during adult neurogenesis. In this study, we found that neonatal mouse cortical astrocytes can be directly converted into neurons when exposed to neurogenic differentiation culture conditions, with insulin being the most critical component. Detailed comparison studies between mouse cortical astrocytes and neuronal progenitor cells (NPCs) demonstrated the converted neuronal cells originate indeed from the astrocytes rather than NPCs. The neurons derived from mouse cortical astrocytes display typical neuronal morphologies, express neuronal markers and possess typical neuronal electrophysiological properties. More importantly, these neurons can survive and mature in the mouse brain in vivo. Finally, by comparing astrocytes from different brain regions, we found that only cortical astrocytes but not astrocytes from other brain regions such as hippocampus and cerebellum can be converted into neurons under the current condition. Altogether, our findings suggest that neonatal astrocytes from certain brain regions possess intrinsic potential to differentiate/transdifferentiate into neurons which may have clinical relevance in the future.

Molecular PET/CT Imaging with 18F-FDG for Diagnosis of SD Rat’s Liver Fibrosis / 中山大学学报(医学科学版)

@#【Objective】To assess the value of 18F-FDG PET/CT for imaging liver fibrosis.【Methods】12 male SD rats （170±10 g）were divided into model group（TAA group）and control group. In the model group，200 mg/kg thioacetamide dissolved in sterile saline was administered to rats by means of intraperitoneal injection twice a week for a total of 6 weeks. In the control group，rats were treated with the same volume of saline. At week 6 after injection，18F- FDG PET/CT imaging was performed on two groups and measurement of the liver 18F-FDG uptake in two groups was taken. After PET/ CT scans， all rats were sacrificed to observe anatomical morphological changes. Liver tissues were harvested for hematoxylin and eosin （H&E） staining，Masson staining and measurement of hydroxyproline levels. 【Results】 Liver anatomical morphology of the TAA-induced rats was roughness with brunt margins and coarse surfaces ，while control rats showed sharp margins and smooth surfaces. HE staining showed visible histological changes that hepatocyte and liver sinus area surrounded by plentiful recruited hepatocyte neutrophils in the model group. Masson staining showed that obvious proliferation of fibroblasts and deposition of collagen in liver tissues in the model group. Model group showed higher hydroxyproline content than that in the control group（P<0.001）. The results of 18F- FDG imaging indicated that apparent liver radioactivity concentration in the model group. 18F-FDG uptake value of liver tissues in the model group was higher than that in the control group（P<0.001）.【Conclusion】18F- FDG PET/CT imaging could be used for diagnosis of liver fibrosis noninvasively.

[Cell proteins that potentially interact with HBV polymerase were identified by co-immunoprecipitation-based LC-MS/MS identification and IPA].

Hepatitis B virus (HBV) is a major cause of chronic liver disease, and frequently results in hepatitis, cirrhosis, and ultimately hepatocellular carcinoma. HBV polymerase (Pol) is an essential viral protein that is important for HBV replication and might be involved in the development of hepatocellular carcinoma. Protein-protein interactions appears to be crucial for its role. The aim of this study was to screen and identify the proteins that interact with Pol using a co-immunoprecipitation-based LC-MS/MS identification technique. The HBV Pol gene was amplified by polymerase chain reaction (PCR) and cloned into pCDNA3.1(+). The recombinant plasmid pCDNA3. 1(+)-Pol-flag was transfected into HeLa cells. Liquid chromatography and tandem mass spectrometry (LC-MS/MS) identified 45 proteins that co-immunoprecipitated with flag-tagged HBV Pol. Eleven of these have previously been reported as proteins that interact with HBV Pol. A proof-of-concept-based Ingenuity Pathway Analysis (IPA, www.ingenuity.com) was used to characterize the functions and pathways of these 45 identified proteins and HBV Pol. Among these proteins, four proteins may play a role in three major molecular cellular networks, and are therefore worthy of further investigation.

Enhanced immune response of a bicistronic DNA vaccine expressing fusion antigen Hsp65-Esat-6 of Mycobacterium Tuberculosis with GM-CSF as a molecular adjuvant

This study aimed to construct a bicistronic DNA vaccine expressing fusion antigen Hsp65-Esat-6 of Mycobacterium tuberculosis with cytokine GM-CSF as a molecular adjuvant (pIRES-Hsp65-ESAT-6-GM-CSF, pIRHEG), and the immune response in mice. C57BL/6 mice were immunized with the recombinant plasmid to detect the titer of antibodies, lymphocyte proliferation, the ratio of CD4+, CD8+T cell and IFN ~ γﻌIL-2 secretion. The titer of antibody, lymphocyte proliferation, the ratio of CD4+T and CD8+T cells and IFN ~ γ, IL-2 secretion of pIRHEG group was significant higher than other recombinant plasmid groups, which significant differed by statistical mean. The bicistronic DNA vaccine could induce an effective immune response in mice and could be used as vital ingredient of a new tuberculosis vaccine candidate.

Construction and expression of a recombinant eukaryotic expression plasmid containing the preS1-preS2-S genes of hepatitis B virus and the granulocyte-macrophage colony stimulating factor gene: A study of its immunomodulatory effects.

A total of 10-20% of the population remains unresponsive or weakly responsive to hepatitis B vaccine, which is composed of hepatitis B surface antigen HBsAg (S protein). Therefore, it is necessary to develop a hepatitis B vaccine with a better penetrating and responsive rate. In the present study, a plasmid pVAX1-L-GM was constructed and its immunomodulatory effect of as hepatitis B virus (HBV) DNA vaccine was analyzed through the immunization of BALB/c mice. Immune responses were measured after immunization by anti-HBsAg, proliferation of splenocytes, the number of CD4+ and CD8+ molecules, CTL cytotoxicity, cytokines of IFN-γ and IL-2 secretion assays. Following the immunization, mice in the pVAX1-L-GM group produced antibody 2 weeks earlier compared to the control plasmid pVAX1 and pVAX1HBsAg groups and antibody levels showed significant differences. Enhanced HBsAg-specific splenocyte proliferation as well as specific cytotoxic activities of splenic CTLs were also detected. Furthermore, pVAX1-L-GM plasmid increased the number of CD4+ and CD8+ molecules on the surface of the spleen T cell and the level of IFN-γ, IL-2 secretion. pVAX1-L-GM induced a specific immune response in mice and enhanced the immune effect. Thus, a foundation was laid for developing immunogenicity of a better prevention and treatment of HBV via a hepatitis B vaccine.

Construction of a fusion expression plasmid containing the G250 gene and human granulocyte-macrophage colony stimulating factor and its significance in renal cell carcinoma.

This study aimed to construct a eukaryotic expression plasmid containing the G250/MN/CA IX (G250) and human granulocyte-macrophage colony stimulating factor (hGM-CSF) genes, and to detect the expression of these proteins in vitro by recombinant plasmids in eukaryotic cells. pORF-hGM-CSF and pcDNA3.0-G250 were used as the template to amplify G250 and hGM-CSF by routine polymerase chain reaction (PCR). The two PCR products were cloned into the eukaryotic vector pVAX1, in order to construct a recombinant plasmid pVAX1-G250-hGM, and the plasmid was transfected into human embryonic kidney 293 cells. The protein expression was then determined by immunocytochemistry, atomic force microscopy, ELISA and Western blotting. DNA sequencing showed that the cloned G250 and hGM-CSF sequences were consistent with the reported Gene Bank ones. Moreover, a high expression was noted following recombinant plasmid transfection of the G250 and hGM-CSF proteins. Thus, the eukaryotic expression vector pVAX1-G250-hGM containing G250 and hGM-CSF was constructed, allowing for the investigation of the anti-G250 antigen vaccine and immune response mechanisms of biological immunotherapy in renal cell carcinoma.