ABSTRACT
Objective To observe the effect of inhibiting the abnormal activation of cdc2 gene on the coordination of mice with Niemann-Pick disease type C(NPC).Methods Recombinant adeno-associated virus(rAAV) encoding cdc2-siRNA was packaged,and then was injected into the cerebellum of 2 weeks old npc-/-mice.Footprint test and vertical screen test were performed to assess the coordination of mice at the age of 8 weeks.Purkinje cells visualized by HE staining in cerebellum were counted,and the phosphorylation of microtubule-associated protein Tau recognized by PHF-1 antibody was detected by immunoblotting technology.Results (1) Footprint test showed that the stride length in cdc2-siRNA npc-/-group((4.92±0.31)cm) was markedly longer than that in empty vector npc-/-group((4.05 ± 0.19) cm) (P＜ 0.05).(2) Vertical screen test showed that the latency to turn head upwards or reach the upper edge of the screen in cdc2-siRNA npc-/-group((26.01± 1.82) s,(50.93±1.98) s) was significantly shorter than that in the empty vector npc-/-group ((31.96± 3.47) s,(56.89 ± 2.97) s),respectively (P＜ 0.05 for all comparisons).(3) The number of Purkinje cells in cerebellum was dramatically increased in cdc2-siRNA npc-/-group(11.0±2.5) compared with the empty vector npc-/-group (5.1 ± 2.2) (P＜0.05).(4)The relative optical densities of cdc2 and phosphorylated Tau immunoreactive bands in cdc2-siRNA npc-/-group(1.42±0.22,0.95±0.31)were significantly lower than those in the empty vector npc-/-group(2.11±0.29,2.61±0.62),respectively (P＜0.05 for all comparisons).Conclusion Inhibiting the abnormal activation of cdc2 gene can improve the coordination of npc-/-mice by ameliorating Purkinje cell's loss and reducing the hyperphosphorylation of Tau in cerebellum.
ABSTRACT
BACKGROUND: Cell division cycle 2 (cdc2) plays an important role in the course of neuronal degeneration in neurodegenerative diseases such as Alzheimer's disease. The silencing of cdc2 gene with adeno-associated virus vector might protect the neurons in neurodegenerative diseases.OBJECTIVE: To pack recombinant adeno-associated virus (rAAV) encoding cdc2-siRNA. DESIGN, TIME AND SETTING: Blank control experiment was performed in the laboratory of Department of Neurology at Wuhan Tongji Hospital between October 2007 and August 2008. MATERIALS: Helper Free adeno-associated virus system (pAAV-MCS-EGFP, p-RC, p-Helper) and AAV-293 cells were purchased from Stratagene. METHODS: The pAAV-MCS-U6-cdc2-siRNA-EGFP expressing plasmid was constructed by molecular biological techniques. The cotransfection of this plasmid, together with p-RC and p-Helper into AAV-293 calls was mediated by calcium acid phosphate. The rAAV encoding cdc2-siRNA (rAAV-U6-cdc2-siRNA-EGFP) was packed and harvested. The silencing effect of this virus on cdc2 gene expression in AAV-293 cells was assessed by Western Blot, and its titer was determined by spot hybridization method. MAIN OUTCOME MEASURES: sequencing of pAAV-MCS-U6-cdc2-siRNA-EGFP plasmid inserting U6-cdc2-siRNA; 3 plasmid pAAV-MCS-U6-cdc2-siRNA-EGFP, p-RC, p-Helper cotransfecting AAV-293 cells; cdc2 expression after rAAV-U6-cdc2-siRNA-EGFP infected AAV-293 cells.RESULTS: ①The successful construction of U6-cdc2-siRNA in pAAV-MCS-EGFP plasmid was proved by DNA sequencing. ②Green fluorescent protein was expressed in AAV-293 cells, and the contransfection was working well. ③The cdc2 gene expression in AAV-293 cells was down-regulated markedly after infection of rAAV-U6-cdc2-siRNA-EGFP. ④The titer of rAAV-U6-cdc2-siRNA-EGFP was 1×10<'12> v.g/mL.CONCLUSION: The package of rAAV encoding cdc2-siRNA is successful. It can silence cdc2 gene effectively.
ABSTRACT
In order to investigate the neuroprotective effects of cyclin-dependent kinase-5 (cdk-5) inhibition in mice with Niemann-Pick disease type C (NPC) (npc(-/-)), recombinant adeno-associated virus (rAAV) carrying the small interfering RNA (siRNA) specific for cdk-5 gene was injected into 3-day-old npc(-/-) mice intracerebroventricularly. The rAAV-GFP-injected age-matched npc(-/-) mice and non-surgery age-matched npc(-/-) mice were employed as controls (n=6-10/group). From the 4th to 8th week after the treatment, mice were weighed, and evaluated for limb motor activity by using the coat hanger test once a week. Eight-week-old npc(-/-) mice were sacrificed by decapitation, and brains were quickly dissected and halved sagittally. Immunohistochemistry, Western blotting, and HE staining were used to evaluate the neuropathology in npc(-/-) mice. The results showed that rAAV-cdk-5-siRNA-GFP significantly reduced the number of axonal spheroids, delayed the death of Purkinje neurons, ameliorated motor defects in npc(-/-) mice, and significantly attenuated the hyperphosphorylation of tau proteins. These data suggested that inhibition of cdk-5 activity has neuroprotective effect on neurons in NPC mice.
ABSTRACT
BACKGROUND: As a main gene engineering vector, adeno-associated virus (AAV) is characterized by its extensive host cells, lasting and stable expression and less immune response to hosts, and is applied widely. But AAV is a kind of defective virus, and need incasing cells to supply E1 protein. As important and special AAV incasing cells, AAV-293 cells can produce E1 in trans. But AAV-293 cells are delicated and cultivated difficultly, and the biological character is easy to be changed. Therefore, it is necessary to establish a culture method of AAV-293 cells to meet the need of gene engineering.OBJECTIVE: To establish a culture method of AAV-293 cells in vitro.DESIGN: An opening study.SETTING: Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology.MATERIALS: AAV-293 cells line was provided by Stratagene Corporation; high-carbohydrate OMEM (H-DMEM) powder by Gibco Company; there plasmids in AAV Helper-Free by Stratagene Company.METHODS: This experiment was carried out in the neurology laboratory of Tongji Hospital in Wuhan during the period from October 2006 to April 2007. AAV-293 cells were resuscitated and cultivated with H-DMEM growth medium in vitro, and were passaged and stored in liquid nitrogen when the cells monolayer confluence reached 50%. At the same time, their growing state was observed by inverted microscope, and their growth curve was noted. According to whether AAV-293 cells could give out green fluorescence or not (observed by fluorescence inverted microscope) after they were cotransfected with the there AAV system plasmids and infected with AAV supernatant, their biological character of packing AAV was assessed.MAIN OUTCOME MEASURES: ① Morphological observation of AAV-293 cells; ② the growth curve; ③ the package of AAV.RESULTS: ① AAV-293 cells observed by fluorescence inverted microscope were growing adhesively well with irregular polygons, light endochylemas and ambiguous nuclei appearances. ②The growth curve showed that the growing adaptive phase was the first day after AAV-293 cells were passaged, the actively growing phase was from the second day to the fifth day, and the growing platform phase was after the sixth day. ③ AAV-293 cells with green fluorescence observed by fluorescence inverted microscope, and cotransfection of the there AAV system plasmids was successful. AAV-293 cells gave out green fluorescence after infected with AAV supernatant, and AAV package succeeded.CONCLUSION: The culture method established by the authors in the experiment is simple and useful, and the cultured AAV-293 cells remain a good function of AAV package.