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ABSTRACT: The characteristic pathological change of Alzheimer's disease (AD) include deposits of β-amyloid protein (Aβ) in brain, neurofibrillary tangles (NFTs), as well as a few neuronal loss. Evidence shows that Aβ causes calcium influx and induces the cleavage of p35 into p25. Furthermore, the binding of p25 to cyclin-dependent kinase 5 (Cdk5) constitutively activates Cdk5. The p25/Cdk5 complex then hyperphosphorylates tau. Tanshinone IIA (tanIIA), a natural product extracted from Chinese herbal medicine Salvia miltiorrhiza BUNGE, has been reported to exert antioxidative activity. However, its neuroprotective activity remains unclear. The present study determined whether tanIIA protects neurons against Aβ(25-35)-induced cytotoxicity and detected the association of this protective effect with calpain and the p35/Cdk5 pathway. The results showed that tanIIA protected neurons against the neurotoxicity of Aβ(25-35), increased the viability of neurons, decreased expression of phosphorylated tau in neurons induced by Aβ(25-35), improved the impairment of the cell ultrastructure (such as nuclear condensation and fragmentation, and neurofibril collapse). Further more, we found that tanIIA maintained the normal expression of p35 on peripheral membranes, and decreased p25 expression in the cytoplasm. TanIIA also inhibited the translocation of Cdk5 from the nucleus into the cytoplasm of primary neurons induced by Aβ(25-35). These data suggested that tanIIA possessed neuroprotective action and the protection may involve in calpain and the p35/Cdk5 pathway.
Neurochemistry International 04/2012; 61(2):227-35. · 2.86 Impact Factor
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ABSTRACT: To construct the recombinant prokaryotic expression plasmid pET/c-ABCSP-Aβ(15-c);, and evaluate the immunogenicity of the fusion protein expressed in E.coli.
The gene fragment HBc88-144 was amplified by PCR and subcloned to pUC19. The APP beta cleavage site peptide(ABCSP) and Aβ(1-15); gene(ABCSP-Aβ(15);) was amplified by PCR and inserted downstream of HBc1-71 in pGEMEX/c1-71. After restriction enzyme digestion, c1-17-ABCSP-Aβ(15); were connected with HBc88-144, yielding the recombinant gene c-ABCSP-Aβ(15-c);. c-ABCSP-Aβ(15-c); gene was subcloned into pET-28a(+).The fusion protein expressed in transformed E.coli BL21 was induced with IPTG and analyzed by SDS-PAGE. The virus-like particles (VLP) formed by fusion protein was observed with Transmission Electron Microscope (TEM). 4 Kunming (KM) mice received intraperitoneal injection (i.p) of fusion protein VLP. The antibody was detected by indirect ELISA.
The recombinant gene was confirmed by restriction enzyme digestion and DNA sequencing. After IPTG induction, fusion protein was expressed and mainly existed in the sediment of the bacterial lysate. The expression level was 40% of all the proteins in the sediment. The fusion protein could form VLP. After 5 times of immunization, the titer of anti-ABCSP and anti-Aβantibody in sera of KM mice reached up to 1:5 000 and 1:10 000 respectively, while the anti-HBc antibody was undetectable.
Recombinant c-ABCSP-Aβ(15-c); gene can be expressed in E.coli. The expressed protein could form VLP and has a strong immunogenicity. This study lays the foundation for the study of AD genetic engineering vaccine.
Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology 11/2011; 27(11):1169-72.
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ABSTRACT: To investigate the effect of [Gly14]-Humanin overexpression on Abeta(25-35);-induced PC12 cell apoptosis.
Recombinant plasmid pcDNA3.1(-)/HNG-FLAG was transfected into PC12 cells by liposome method. The subclone cell lines were obtained by persistent G418 selection. The HNG gene expression of PC12 cells was detected by immunocytochemistry. After being treated with 25 micromol/L Abeta(25-35); for 24 h, cell viability was determined by MTT assay, and apoptosis rate was detected by using flow cytometric analysis. Hochest33258 staining was used to observe the morphological changes of cellular nuclei.
PC12 cell lines stably expressing HNG gene was successfully selected. After being treated with 25 micromol/L Abeta(25-35); for 24 h, cell viability of PC12 cells overexpression HNG was significant elevated compared with empty plasmid transfected cells (P<0.05), and the apoptosis rate was lower significantly (P<0.05). By Hoechst 33258 staining, the nuclei of empty plasmid transfected PC12 cells exhibited highly condensed and fragmented nuclei morphology which was the typical characteristics of apoptosis, and the nuclei of PC12 cells overexpression HNG were round and homogeneously stained.
Overexpression of HNG prevented the cell apoptosis induced by Abeta(25-35); in PC12 cells.
Xi bao yu fen zi mian yi xue za zhi = Chinese journal of cellular and molecular immunology 05/2010; 26(5):427-30.
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ABSTRACT: To investigate podocyte injury and the expression of nephrin and VEGF in rat nephrosis model induced by adriamycin.
The rat adriamycin induced nephrosis model was established, while the biochemical indicators in blood and urine were measured and the pathological changes of the renal tissue were evaluated by light microscope and electron microscope. The podocyte number was counted, and the expression levels of nephrin, VEGF were examined at different time by means of immunohistochemistry.
After second injected with adriamycin,the model group nephrin presented a weak signal in the end of the first week (P < 0.05), and the expression of VEGF started to increase at the end of the eighth week (P < 0.05). The podocyte number decreased at the end of the eighth week (P < 0.05). The expression of nephrin and the number of podocyte were negatively correlated with the 24-hour urine protein, blood urea nitrogen and serum creatinine; while the expression of VEGF was positively correlated with the 24-hour urine protein, blood urea nitrogen and serum creatinine.
The decrease of nephrin expression and the change of its distribution might be the significant factors resulting in considerable proteinuria. VEGF participated in the process of proteinuria and glomerular sclerosis in the development of rat adriamycin nephrosis.
Sichuan da xue xue bao. Yi xue ban = Journal of Sichuan University. Medical science edition 05/2010; 41(3):458-63.
