OBJECTIVETo detect whether the murine T-cell lymphoma cell line EL4 could be infected by murine cytomegalovirus (MCMV), and to observe the morphological changes and apoptosis of El4 cells before and after infection.

METHODSEL4 cells were infected with MCMV smith strain with 1, 10 and 100 multiplicity of infection (MOI) respectively. The morphology of the cells was observed by light microscopy and Wright's-Giemsa staining. The survival rate was calculated by trypan blue staining. RT-PCR-based assay was used to detect the copy number of MCMV-DNA in the infected ELA cells. Flow cytometry was used to detect apoptosis. RT-qPCR was used to detect the mRNA expression levels of P53, P21, cFlip and Caspase 8. The protein expression levels of Caspase8, P53, BAX, BCL-2 and Cleaved Caspase3 proteins were detected by Western blot.

RESULTSAfter Wright-Giemsa staining, it was found that the infected EL4 cells displayed larger volume, irregular nuclei and the folded twist under light microscopy. Compared with the normal control group, the survival rate of EL4 cells decreased, and the apoptosis rate statistically significantly (P<0.05) increased with the increasing MOI and the infected time in each group. While, the level of apoptosis protein P53, BAX/BCL-2, Cleaved-caspase3 and Caspase8 were up-regulated. And the survival rate, apoptosis rate and the apoptosis protein level of infected EL4 cells with MOI=10 were the most obvious at the 5day. Compared with MCMV infection group (MOI=60), the content of MCMV DNA in EL4 cells was decreased in MCMV+GGV group ［MOI=60, GCV 25 (g/ml)］, and the cell apoptosis rate and apoptosis protein expression of P53, Caspase8, BAX/BCL-2 were decreased (P<0.05).

CONCLUSIONMurine T-cell lymphoma cell line EL4 can be infected by MCMV and displayes an obvious apoptosis phenomenon. MCMV may up-regulate the expression levels of apoptosis protein P53, BAX-BCL-2, Cleaved-caspase3 and Caspase8 in EL4 cells. The drug ganciclovir reduces the copy mumber of MCMV DNA in infected EL4 cells and inhibited the killing effect of MCMV on EL4 cells.

Animals ; Apoptosis ; Caspase 8 ; Ganciclovir ; Lymphoma, T-Cell ; Mice ; Muromegalovirus

BACKGROUNDMurine cytomegalovirus (MCMV) early protein M112-113 is involved in viral DNA replication and believed to play a crucial role in the viral pathogenesis. To investigate the biological function of M112-113 protein in the pathogenesis of the brain disorders caused by cytomegalovirus (CMV), a screening for proteins interacting with M112-113 was performed by a yeast two-hybrid system.

METHODSBait plasmid pGBKT7-M112-113 was constructed and transformed into AH109 yeast. After confirmation of the expression of MCMV M112-113 in yeast, the bait yeast was mated with a prey yeast containing mouse brain cDNA library plasmid to screen the proteins interacting with M112-113. Interactions between M112-113 and the obtained proteins were verified by yeast two-hybrid assay and chemiluminescent co-immunoprecipitaion.

RESULTSTwo proteins interacting with M112-113 were identified, including metastasis-associated 1 (MTA1) and zinc finger, CCHC domain containing 18 (ZCCHC18). M112-113 protein could interact with MTA1 or ZCCHC18 in yeast and mammalian cells.

CONCLUSIONThe interactions of M112-113 with MTA1 or ZCCHC18 may be related to the pathogenesis of MCMV-associated disease in central nervous system.

Animals ; Brain ; metabolism ; Cell Line ; Humans ; Immunoprecipitation ; Mice ; Muromegalovirus ; metabolism ; Plasmids ; Protein Binding ; Two-Hybrid System Techniques ; Viral Proteins ; metabolism

OBJECTIVETo establish a BALB/c mice model system of cytomegalovirus-induced myocarditis.

METHODSTwenty five specific pathogen-free inbred female BALB/c mice (5 weeks old, 16 - 18 g, seronegative for MCMV) were infected with 1 x 10(4) PFU MCMV by the intraperitoneal (i.p.) route. All experimental mice were sacrificed at 3, 5, 7, 10, 14 days i.p. (n = 5 per time point). Hearts were removed under aseptic conditions, and were transected along the midline. One part of each heart was processed with Bouin's fixative for histological examination. The other part of each heart was immediately frozen in liquid nitrogen and stored at -80 degrees C until MCMV titre was determined by plaque assay. Serum cTnI level was assayed by ELISA.

RESULTSMCMV was detected in the hearts at extremely low levels on 3 days i.p. and could not be detected on 10 days i.p. A mixed cellular infiltrate composed of polymorphonuclear neutrophils and mononuclear lymphocytes was observed on 3 days, which reached a peak at 7 to 10 days after MCMV infection and was maintained for at least 3 - 4 months postinfection. Serum cTnI levels were elevated on 3 days i.p., reaching a peak at 7 to 10 days i.p..

CONCLUSIONSThese data highlight the possible therapeutic uses of antiviral drugs in viral myocarditis as well as further elucidating the pathogenic nature of the disease.

Animals ; Disease Models, Animal ; Female ; Herpesviridae Infections ; pathology ; Mice ; Mice, Inbred BALB C ; Muromegalovirus ; Myocarditis ; virology ; Troponin I ; metabolism

To study the effects of mouse cytomegalovirus (MCMV) on the in vitro maturation, fertilization, cleavage and blastula formation of mouse oocytes, the immature oocytes were infected in vitro by MCMVs of different dosages (100 TCID(50), 10 TCID(50) and 1 TCID(50)). The oocytes were then observed for in vitro maturation, fertilization, cleavage and blastula formation and the ultrastructural changes after the culture with the viruses. Our results showed that no significant differences were found in IVM, IVF, cleavage and blastula formation among the groups treated with of virus of various dosages. And ultrastructural abnormality was observed in the oocytes treated by 100 TCID(50) of viruses. It is concluded that MCMV did not have any conspicuous effects on IVM, IVF, cleavage and blastula formation of murine immature oocytes.
Blastocyst ; Cells, Cultured ; Cleavage Stage, Ovum ; Cytomegalovirus Infections ; Fertilization ; Muromegalovirus/*pathogenicity ; Oocytes/cytology ; Oocytes/growth & development ; Oocytes/*virology

This study was aimed to explore the infection characteristics of murine mononuclear cell subpopulations in bone marrow with murine cytomegalovirus (MCMV). Subpopulations of mononuclear cells, including lin(+), lin(-), lin(-)CD117(+) and lin(-)CD117(-) cells, were infected with MCMV after being separated by MACS, and induced to differentiation by adding cytokines or inducer, then nucleic acid and proteins were detected. The results indicated that the MCMV DNA, IE transcripts and IE protein could be detected in the lin(+) cells infected with MCMV; no virus products were detected in infected lin(-) cells without adding any stimulating factors, while IE and E transcripts and proteins were detected after adding GM-CSF, rhEPO or phorbol ester in the lin(-) cells infected with MCMV. Furthermore, no IE or E gene transcripts were detected in the lin(-)CD117(+) and lin(-)CD117(-) cells, but the cell colony formation of lin(-)CD117(+) hematopoietic stem and progenitor cells was inhibited after MCMV infection and expression of CD117 antigen on cell surface of the lin(-) cells was downregulated. It is concluded that MCMV can latently infect subpopulations of mononuclear cells in the murine bone marrow. Cells which are of characteristics of primitive stem and progenitor cells are not susceptible to MCMV, but infection of these cells with MCMV can inhibit functions of cells and downregulate the expression of antigen on cells surface.
Animals ; Bone Marrow ; virology ; Cytomegalovirus Infections ; Mice ; Mice, Inbred BALB C ; Monocytes ; virology ; Muromegalovirus ; physiology ; Proto-Oncogene Proteins c-kit ; Stem Cells ; virology

Cytomegalovirus (CMV) is distinct among members of the Herpesviridae family for having the largest dsDNA genome (230 kb). Packaging of large dsDNA genome is known to give rise to a highly pressurized viral capsid, but molecular interactions conducive to the formation of CMV capsid resistant to pressurization have not been described. Here, we report a cryo electron microscopy (cryoEM) structure of the murine cytomegalovirus (MCMV) capsid at a 9.1 Å resolution and describe the molecular interactions among the ∼3000 protein molecules in the MCMV capsid at the secondary structure level. Secondary structural elements are resolved to provide landmarks for correlating with results from sequence-based prediction and for structure-based homology modeling. The major capsid protein (MCP) upper domain (MCPud) contains α-helices and β-sheets conserved with those in MCPud of herpes simplex virus type 1 (HSV-1), with the largest differences identified as a "saddle loop" region, located at the tip of MCPud and involved in interaction with the smallest capsid protein (SCP). Interactions among the bacteriophage HK97-like floor domain of MCP, the middle domain of MCP, the hook and clamp domains of the triplex proteins (hoop and clamp domains of TRI-1 and clamp domain of TRI-2) contribute to the formation of a mature capsid. These results offer a framework for understanding how cytomegalovirus uses various secondary structural elements of its capsid proteins to build a robust capsid for packaging its large dsDNA genome inside and for attaching unique functional tegument proteins outside.
Amino Acid Sequence ; Capsid Proteins ; chemistry ; metabolism ; ultrastructure ; Cryoelectron Microscopy ; Models, Molecular ; Molecular Sequence Data ; Muromegalovirus ; chemistry ; ultrastructure ; Protein Binding ; Protein Multimerization ; Protein Structure, Quaternary ; Protein Structure, Tertiary

OBJECTIVEThe goal of this study was to investigate whether murine cytomegalovirus (MCMV) is able to exacerbate the atherosclerotic process in apolipoprotein E knockout (apoE -/-) mice, and the effect of fluvastatin on the atherogenesis.

METHODSThe apoE-/- mice kept on a west diet were given low dosage of MCMV. At 14,18 and 24 weeks post infection, AS lesion were measured on aorta. The fluvastatin was administered, and AS lesion were measured accordingly above.

RESULTSWe observed that in the chronic phase of the infection, AS lesion area was significantly increased. MCMV gB mRNA was not amplified by real-time PCR from the arterial wall. The IgG antibody level of MCMV in blood plasma and the content of virus DNA in salivary gland were not correlated with AS lesions. After the administration of fluvastatin, there was no significant difference of AS lesions between MCMV infected group and mock-infected group.

CONCLUSIONMCMV may aggravate the AS lesion in apoE -/- mice in the chronic phase of infection, and promote more severe type of AS lesions. But it might not be the direct effects of mechanism of MCMV on the local lesion of AS. Fluvastatin could meliorate the progression of AS after MCMV infection, but this was not accomplished by decreasing MCMV duplication.

Animals ; Aorta ; drug effects ; Apolipoproteins E ; deficiency ; genetics ; Atherosclerosis ; blood ; drug therapy ; genetics ; virology ; Fatty Acids, Monounsaturated ; pharmacology ; Herpesviridae Infections ; blood ; drug therapy ; virology ; Immunoglobulin G ; blood ; Indoles ; pharmacology ; Male ; Mice ; Mice, Knockout ; Muromegalovirus ; genetics

OBJECTIVETo investigate whether allitridin could interfere with the effects of murine cytomegalovirus (MCMV) infection on the transcription, expression and function of IL-12 genes in order to further explore the mechanism of allitridin against MCMV.

METHODSixty mice were randomly divided into allitridin treated group, placebo and blank controls. Allitridin was intra-peritoneal injected to mice in treated group once a day with general dosage (25 mg x kg(-1)) at 24 hours after MCMV infection, and the same dosage of physiological saline were given to placebo and blank groups. Four experimental mice were sacrificed at 3, 5, 7, 10, 14 days after treatment (n = 4 per time point), respectively. The expression of IL-12 p70 and IFN-gamma in supernatant of spleen cell cultures were measured by double-antibody sandwich ELISA, and IL-12 p35 and p40 mRNAs in spleen cells were analyzed by RT-PCR.

RESULTIn systemic infection mice, the expression of both IL-12 p70 protein and p35 mRNA significantly increased on day 3 post-infection (pi); then rapidly and markedly decreased on day 5 pi and later. The level of IFN-gamma reached the peak on day 3 pi, then gradually dropped and returned to normal levels during the period of day 10 to 14 pi, and IL-12 p40 mRNA level was persistently and significantly higher after infection. In allitridin treated mice, the levels of IL-12 p70 protein, IL-12 p35 and p40 mRNAs reached the peak on day 3 after treatment (P < 0.05), and then rapidly dropped to the normal levels during the period of 5-14 days. Level of IFN-gamma was also reached the peak on day 3 after treatment; however, it dropped a little on day 5 and then gradually increased and was much higher than those of both placebo and bland controls during the period of day 7 to 14 after treatment (P < 0.01).

CONCLUSIONAllitridin could completely correct the disturbance of expression of IL-12 gene caused by MCMV and persistently promote IFN-gamma expression, which was useful for enhancing the specific cellular immune reactions against CMV and clearance of CMV viruses from host. The result suggests another mechanism of allitridin against CMV.

Allyl Compounds ; therapeutic use ; Animals ; Antiviral Agents ; therapeutic use ; Enzyme-Linked Immunosorbent Assay ; Female ; Herpesviridae Infections ; drug therapy ; metabolism ; Interleukin-12 ; genetics ; metabolism ; Mice ; Mice, Inbred BALB C ; Muromegalovirus ; drug effects ; pathogenicity ; Reverse Transcriptase Polymerase Chain Reaction ; Sulfides ; therapeutic use

In order to investigate the human cytomegalovirus (HCMV) infection, the mouse cytomegalovirus (MCMV) infected mice were experimentally studied. 6 to 8 week old female BALB/C mice with immunosuppression were selected to undergo the MCMV inoculations: intracranial inoculation and peritoneal inoculation. MCMV of the infected mice in various organs and tissues were detected by using beta-gal staining and in situ nucleic acid hybridization assay. The pathological changes were observed in HE staining paraffin-embedded sections. It was found that all the MCMV infected mice showed the retardation of growth and development, and feather looseness. Both intracranial inoculation of 10(4) PFU viruses or peritoneal inoculation of 10(6) PFU viruses resulted in the pathological changes, to some extent, of various organs and tissues in the mice. The pathological changes in liver were consistent with the amount of beta-gal staining positive cells, indicating the liver lesions were mainly caused by viral proliferation. It was also found that the viruses in the immunosuppressed mice subjected to intracranial inoculation could spread to whole body organs, while the viruses in the immunosuppressed mice subjected to intrapeitoneal inoculation couldn't spread to the brain, suggesting blood-brain barrier could prevent the virus from spreading to the brain.
Blood-Brain Barrier ; Brain/pathology ; Brain/virology ; Disease Models, Animal ; *Herpesviridae Infections/pathology ; *Herpesviridae Infections/virology ; Immunocompromised Host ; Liver/pathology ; Liver/virology ; Lung/pathology ; Lung/virology ; Mice, Inbred BALB C ; *Muromegalovirus

In order to investigate the human cytomegalovirus (HCMV) infection, the mouse cytomegalovirus (MCMV) infected mice were experimentally studied. 6 to 8 week old female BALB/C mice with immunosuppression were selected to undergo the MCMV inoculations: intracranial inoculation and peritoneal inoculation. MCMV of the infected mice in various organs and tissues were detected by using beta-gal staining and in situ nucleic acid hybridization assay. The pathological changes were observed in HE staining paraffin-embedded sections. It was found that all the MCMV infected mice showed the retardation of growth and development, and feather looseness. Both intracranial inoculation of 10(4) PFU viruses or peritoneal inoculation of 10(6) PFU viruses resulted in the pathological changes, to some extent, of various organs and tissues in the mice. The pathological changes in liver were consistent with the amount of beta-gal staining positive cells, indicating the liver lesions were mainly caused by viral proliferation. It was also found that the viruses in the immunosuppressed mice subjected to intracranial inoculation could spread to whole body organs, while the viruses in the immunosuppressed mice subjected to intrapeitoneal inoculation couldn't spread to the brain, suggesting blood-brain barrier could prevent the virus from spreading to the brain.
Animals ; Blood-Brain Barrier ; Brain ; pathology ; virology ; Disease Models, Animal ; Female ; Herpesviridae Infections ; pathology ; virology ; Immunocompromised Host ; Liver ; pathology ; virology ; Lung ; pathology ; virology ; Mice ; Mice, Inbred BALB C ; Muromegalovirus