OBJECTIVE: To investigate the effect of silencing CD46 and desmoglein 2 (DSG2) in host A549 cells on the entry of human adenovirus type 3 (HAdV-3) and type 7 (HAdV-7) and host cell secretion of inflammatory cytokines. METHODS: RNA interference technique was use to silence the expression of CD46 or DSG2 in human epithelial alveolar A549 cells as the host cells of HAdV-3 or HAdV-7. The binding of the viruses with CD46 and DSG2 were observed with immunofluorescence staining at 0.5 and 1 h after viral infection. The viral load in the host cells was determined with qRT-PCR, and IL-8 secretion level was measured using ELISA. RESULTS: In infected A549 cells, immunofluorescent staining revealed colocalization of HAdV-3 and HAdV-37 with their receptors CD46 and DSG2 at 0.5 h and 2 h after infection, and the copy number of the viruses increased progressively after the infection in a time-dependent manner. In A549 cells with CD46 silencing, the virus titers were significantly lower at 2, 6, 12 and 24 h postinfection in comparison with the cells without gene silencing; the virus titers were also significantly decreased in the cells with DSG2 silencing. The secretion level of IL-8 increased significantly in A549 cells without siRNA transfection following infection with HAdV-3 and HAdV-7 (P < 0.0001), but decreased significantly in cells with CD46 and DSG2 silencing (P < 0.0001). CONCLUSION HAdV-3 and HAdV-7 enter host cells by binding to their receptors CD46 and DSG2, and virus titer and cytokines release increase with infection time. Silencing CD46 and DSG2 can inhibit virus entry and cytokine IL-8 production in host cells.
A549 Cells ; Adenoviruses, Human/metabolism* ; Desmoglein 2/metabolism* ; Humans ; Interleukin-8 ; Membrane Cofactor Protein/genetics* ; RNA, Small Interfering

We wished to study the intracellular transport of adenoviruses. We constructed a novel recombinant adenovirus in which the structural protein IX was labeled with a mini-singlet oxygen generator (miniSOG). The miniSOG gene was synthesized by overlapping extension polymerase chain reaction (PCR), cloned to the pcDNA3 vector, and expressed in 293 cells. Activation of miniSOG generated sufficient numbers of singlet oxygen molecules to catalyze polymerization of diaminobenzidine into an osmiophilic reaction product resolvable by transmission electron microscopy (TEM). To construct miniSOG-labelled recombinant adenoviruses, the miniSOG gene was subcloned downstream of the IX gene in a pShuttle plasmid. Adenoviral plasmid pAd5-IXSOG was generated by homologous recombination of the modified shuttle plasmid (pShuttle-IXSOG) with the backbone plasmid (pAdeasy-1) in the BJ5183 strain of Eschericia coli. Adenovirus HAdV-5-IXSOG was rescued by transfection of 293 cells with the linearized pAd5-IXSOG. After propagation, virions were purified using the CsC1 ultracentrifugation method. Finally, HAdV-5-IXSOG in 2.0 mL with a particle titer of 6 x 1011 vp/mL was obtained. Morphology of HAdV-5-IXSOG was verified by TEM. Fusion of IX with the miniSOG gene was confirmed by PCR. In conclusion, miniSOG-labeled recombinant adenoviruses were constructed, which could be valuable tools for virus tracking by TEM.
Adenoviruses, Human ; chemistry ; genetics ; metabolism ; Arabidopsis Proteins ; chemistry ; genetics ; metabolism ; Flavoproteins ; chemistry ; genetics ; metabolism ; Humans ; Phototropins ; chemistry ; genetics ; metabolism ; Singlet Oxygen ; chemistry ; Staining and Labeling ; Transfection

Reducing lactate accumulation has always been a goal of the mammalian cell biotechnology industry. When animal cells are cultured in vitro, the accumulation of lactate is mainly the combined result of two metabolic pathways. On one hand, glucose generates lactate under the function of lactate dehydrogenase A (LDHA); on the other hand, lactate can be oxidized to pyruvate by LDHB or LDHC and re-enter the TCA cycle. This study comprehensively evaluated the effects of LDH manipulation on the growth, metabolism and human adenovirus (HAdV) production of human embryonic kidney 293 (HEK-293) cells, providing a theoretical basis for engineering the lactate metabolism in mammalian cells. By knocking out ldha gene and overexpression of ldhb and ldhc genes, the metabolic efficiency of HEK-293 cells was effectively improved, and HAdV production was significantly increased. Compared with the control cell, LDH manipulation promoted cell growth, reduced the accumulation of lactate and ammonia, significantly enhanced the efficiency of substrate and energy metabolism of cells, and significantly increased the HAdV production capacity of HEK-293 cells. Among these LDH manipulation measures, ldhc gene overexpression performed the best, with the maximum cell density increased by about 38.7%. The yield of lactate to glucose and ammonia to glutamine decreased by 33.8% and 63.3%, respectively; and HAdV titer increased by at least 16 times. In addition, the ATP production rate, ATP/O₂ ratio, ATP/ADP ratio and NADH content of the modified cell lines were increased to varying degrees, and the energy metabolic efficiency was significantly improved.
Animals ; Humans ; L-Lactate Dehydrogenase/genetics* ; Lactic Acid ; Adenoviruses, Human ; Ammonia ; HEK293 Cells ; Glucose/metabolism* ; Adenosine Triphosphate/metabolism* ; Kidney/metabolism* ; Mammals/metabolism*

To investigate the components of fibrillous inclusion body (FIB), which was formed in packaging cells during the replication of human adenovirus type 41 (Ad41), Ad41 long fiber knob (LFK) and short fiber knob (SFK) proteins were expressed in prokaryote respectively and then used to immunize BALI mice for preparation of anti-LFK serum and anti-SFK sera. The activity and specificity of anti-LFK and an ti-SFK sera were confirmed with Western blot, indirect immunofluorescence assay (IFA) and immunonegative staining, suggesting these sera could be applied in immuno-colloidal gold labelling electron microscopy (EM). 293TE cells were infected with wild-type Ad41. Ultrathin sections of infected cells were made, and labelled with immuno-colloidal gold technique using anti-Ad41 sera, anti-LFK sera, anti-SFK sera, or anti-fiber monoclonal antibody 4D2, respectively. The labelled sections were observed under EM, and the results demonstrated that both Ad41 long fiber protein and short fiber protein were included FIB.
Adenovirus Infections, Human ; virology ; Adenoviruses, Human ; genetics ; metabolism ; ultrastructure ; Animals ; Female ; Humans ; Inclusion Bodies, Viral ; ultrastructure ; Mice ; Mice, Inbred BALB C ; Microscopy, Immunoelectron

Human adenovirus type 41 (HAdV-41) is considered to be a "fastidious adenovirus". E1-deleted HAdV-41 cannot be rescued or amplified in 293 cells. To propagate recombinant HAdV-41 in 293 cells, the backbone plasmid pAdbone41 was reconstructed. That is, the E3 coding sequence of HAdV-41 was deleted and replaced with the HAdV-5 E4orf6 gene; and the E1A enhancer of HAdV-5 was inserted upstream of the E4 promoter of HAdV-41. Novel adenoviral plasmid pAd41E4EE-GFP was generated by homologous recombination of the shuttle plasmid pSh41-GFP with the modified backbone plasmid in the Escherichia coli BJ5183 strain. Adenovirus HAdV-41-E4EE-GFP was rescued by transfecting 293 cells with linearized pAd41E4EE-GFP. After seven rounds of propagation, viruses were purified by the CsCl ultracentrifugation method. HAdV-41-E4EE-GFP in 1.0 ml with a particle titer of 8 x 10(10) vp/mL was obtained which had a particle-to-infectious ratio of 50 : 1. The genome of HAdV-41-E4EE-GFP was confirmed by restriction analyses and polymerase chain reaction. These results showed that a novel HAdV-41 vector system was established in which recombinant HAdV-41 could be constructed and packaged in 293 cells.
Adenoviruses, Human ; genetics ; growth & development ; physiology ; Cell Line ; Genetic Vectors ; genetics ; physiology ; Green Fluorescent Proteins ; genetics ; metabolism ; Humans ; Plasmids ; genetics ; metabolism ; Recombination, Genetic ; Transfection ; Virus Assembly

OBJECTIVETo explore the effect of recombinant human adenovirus p53 (rAd-p53) combined with cisplatin on the expression of human lung adenocarcinoma A549 cells.

METHODSHuman lung adenocarcinoma A549 cells were treated with rAd-p53 combined with cisplatin (combination group) or with cisplatin alone(cisplatin group). The expressions of the cell genes were compared between these two groups and the results were analyzed by SAM software.

RESULTA total of 43 differential genes were found, 15 of which were up-regulated and 28 were down-regulated.

CONCLUSIONFollowing introduction of rAd-p53, many genes regulating cell cycle, proliferation and apoptosis expresses up or down which significantly enhance chemosensitivity and killing efficiency of cisplatin on human lung adenocarcinoma A549 cells.

Adenocarcinoma ; metabolism ; pathology ; Adenoviruses, Human ; genetics ; Cell Line, Tumor ; Cisplatin ; pharmacology ; Gene Expression Profiling ; Genes, p53 ; genetics ; Humans ; Lung Neoplasms ; metabolism ; pathology ; Transfection

OBJECTIVETo construct the adenoviral vector containing human Bcl-2 gene and to study the expression of the gene in the spiral ganglion cells (SGC) in vitro.

METHODSHuman Bcl-2 cDNA obtained from the plasmid pUC-CAGGS/Bcl-2 was cloned into the plasmid pAdTrack-CMV. Then, pAdTrack/Bcl-2 was cotransferred with adenoviral backbone vector into E. coli strain BJ5183. The recombinant adenoviral plasmid was identified by restriction analysis with Pac I and transfected into HEK293 cells to package and amplify recombinant adenovirus particles which would be identified by Electron microscope. After the adenovirus infected the rat spiral ganglion cells, the expression of Bcl-2 gene was detected by Western Blot and RT-PCR.

RESULTSThe recombinant AdEGFP/Bcl-2 plasmid was correctly constructed and confirmed by restriction endonuclease analysis. The viral particles in HEK293 cells were identified by Electron microscope. RT-PCR and Western blot showed that Bcl-2 gene was exactly transcripted and expressed in transgene SGC.

CONCLUSIONSThe method based on homologous recombination in bacteria is simple and high efficient. The recombinant adenoviral vector containing human Bcl-2 cDNA was constructed and the transgene SGC expressed human Bcl-2 gene in vitro successfully. It provided foundation for the further study of protection for the impaired SGC by hBcl-2 gene.

Adenoviruses, Human ; genetics ; Animals ; Cells, Cultured ; Genes, Homeobox ; Genes, bcl-2 ; Genetic Vectors ; Humans ; Rats ; Rats, Sprague-Dawley ; Recombination, Genetic ; Spiral Ganglion ; metabolism ; Transfection ; Transgenes

Adenovirus type 40 and 41 (Ad40, Ad41), which belong to human adenovirus subgroup F, are called fastidious adenoviruses due to their property of poor growth in cultured cell lines in vitro The effect of expression of exogenous E1B55K in Hep2 on Ad41 replication in this cell line was investigated. E1B55K gene was amplified by PCR with DNA extracted from Ad41-positive feces supernatant as template. Eukaryotic expression plasmid (pcDNA3) carrying E1B55K was constructed, purified, and transferred into Hep2 cell. Expression of E1B55K in G418-resistant clones was assayed by RT-PCR, and one clone named as Hep2-E1B4#4 could produce more Ad41 progenies when compared with other clones by the method of inducing complete cytopathic effect (CPE) in 293 cells. Infection of equivalent Ad41 caused more significant cytopathic effect (CPE) in Hep2-E1B#4 than that in the control cells of Hep2 or Hep2-DNA3, also suggesting enhanced viral replication in Hep2-E1B#4. The titer of Ad41 was further determined by method of immunocytochemical staining, and semi-quantity PCR was employed to compare the copy number of Ad41 genome DNA. The results showed that the yield of Ad41 in Hep2-E1B#4 was more than 9 times of that in control cells when equal amount of seed viruses were incubated, and the copy number of Ad41 genome increased 4 times in the raw extract from the infected Hep2-E1B#4 when compared with that from control cells. In conclusion, E1B55K gene transfer improved the ability of Hep2 in packaging Ad41, and the Hep2-E1B#4 cell line, which expressed E1B55K constitutively, would be helpful in isolation, cultivation and amplification of Ad41.
Adenovirus E1B Proteins ; genetics ; metabolism ; Adenoviruses, Human ; genetics ; Cell Line, Tumor ; Gene Expression ; Humans ; Immunohistochemistry ; Reverse Transcriptase Polymerase Chain Reaction ; Virus Replication ; genetics

Objective: To express DNA-binding protein (DBP) of human adenovirus (HAdV) type 7 using the prokaryotic expression system, and product anti-HAdV-7 DBP rabbit polyclonal antibody. Methods: The HAdV-7 DBP gene was synthesized and cloned into prokaryotic expressing vector pET30a, and the recombinant plasmid was transformed into E. coli BL21 (DE3) competent cell. The recombinant protein DBP was expressed by induced Isopropyl-beta-D-thiogalactopyranoside (IPTG) and purified with Ni-NTA affinity column. The titer of anti-DBP polyclonal antibody produced in immunized rabbit was measured by indirect ELISA, and the specificity of the antibody was identified by Western blotting and indirect immunofluorescence assay (IFA). In addition, purified rDBP was used as coating antigen for indirect ELISA assay to detect specific IgM and IgG antibodies against DBP in the serum of children infected with HAdV. Results: The HAdV-7 DBP plasmid was constructed successfully. The purified recombinant DBP was more than 95% after purification. The titer of polyclonal antibody was 1∶1 024 000. The polyclonal antibody showed high specificity in vitro using Western blotting and IFA. The positive rate of specific anti-DBP IgM and IgG antibody in acute-phase serum samples collected from children infected with HAdV were 50.0% (19/38) and 63.2% (24/38), respectively, using indirect ELISA. Conclusion: In summary, the HAdV-7 rDBP is expressed using prokaryotic expression system, and the recombinant HAdV-7 DBP protein and the anti-DBP rabbit polyclonal antibody with high titer are prepared.
Adenoviruses, Human/genetics* ; Animals ; Antibody Specificity ; Blotting, Western ; DNA-Binding Proteins/metabolism* ; Enzyme-Linked Immunosorbent Assay ; Escherichia coli/genetics* ; Immunoglobulin G ; Rabbits

OBJECTIVETo construct the recombinant adenovirus encoding antisense c-myc fragment and to investigate its effect on the chemotherapy sensitivity of osteosarcoma MG-63 cells to cisplatin.

METHODSThe recombinant adenovirus (Ad-Asc-myc) encoding antisense c-myc fragment was constructed by cloning c-myc cDNA of about 720 base pairs in a reverse direction into adenovirus vector, then undergoing recombination, amplifying and being complemented in vivo. The osteosarcoma MG-63 cells were transfected by the Ad-Asc-myc in vitro, and Wright staining, Acridine Orange staining, Western Blot, MTT, Flow Cytometry (FCM) were used to study cell morphology, expression of c-myc protein, tumor cell proliferation in vitro, apoptosis and cell cycle change.

RESULTSAd-Asc-myc encoding antisense c-myc fragment was obtained with the titer of 2 x 10(9) pfu/ml. Ad-Asc-myc down-regulated the expression of c-myc protein after transfected MG-63 cells for 48 h, combined with the treatment of 2.0, 5.0 microg/ml cisplatin for 2 h could inhibit tumor cells proliferation in vitro by 33.4% and 54.2% respectively, which were significantly difference compared with control recombinant adenovirus (Ad-LacZ) groups (P < 0.05). Acridine Orange staining and FCM analysis showed that Ad-Asc-myc could induce apoptosis of transfected cells, which was enhanced by the treatment of cisplatin cell. Cycle analysis showed that obvious G2/M phase arrested in transfected cells.

CONCLUSIONAd-Asc-myc increases the chemotherapy sensitivity of osteosarcoma MG-63 cells to cisplatin as well as induced apoptosis.

Adenoviruses, Human ; genetics ; Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; genetics ; Cisplatin ; pharmacology ; DNA, Antisense ; genetics ; Genes, myc ; Genetic Vectors ; Humans ; Osteosarcoma ; genetics ; metabolism ; pathology ; Proto-Oncogene Proteins c-myc ; metabolism ; Recombination, Genetic ; Transfection ; Tumor Cells, Cultured