Murine cytomegalovirus (MCMV) infection upregulates P38 MAP kinase in aortas of Apo E KO mice: a molecular mechanism for MCMV-induced acceleration of atherosclerosis.

Multiple studies suggest an association between cytomegalovirus (CMV) infection and atherogenesis; however, the molecular mechanisms by which viral infection might exacerbate atherosclerosis are not well understood. Aortas of MCMV-infected and uninfected Apo E knockout (KO) mice were analyzed for atherosclerotic lesion development and differential gene expression. Lesions in the infected mice were larger and showed more advanced disease compared to the uninfected mice. Sixty percent of the genes in the MAPK pathway were upregulated in the infected mice. p38 and ERK 1/2 MAPK genes were 5.6- and 2.0-fold higher, respectively, in aortas of infected vs. uninfected mice. Levels of VCAM-1, ICAM-1, and MCP-1 were ~2.0-2.6-fold higher in aortas of infected vs. uninfected mice. Inhibition of p38 with SB203580 resulted in lower levels of pro-atherogenic molecules and MCMV viral load in aortas of infected mice. MCMV-induced upregulation of p38 may drive the virus-induced acceleration of atherogenesis observed in our model.

Paradoxical response to prophylactic Didox (N-3, 4 trihydroxybenzamide) treatment in murine cytomegalovirus-infected mice.

BACKGROUND: In this study, we investigated the effect of Didox (DX) on the pathogenicity of and host responses to murine cytomegalovirus (MCMV) infection. METHODS: In vitro efficacy of DX against MCMV was determined using plaque reduction assays. For in vivo studies, mice infected with a sublethal dose (10(4) PFU) of MCMV were treated daily with DX (200 mg/kg) using either a prophylactic or delayed protocol. At predetermined intervals, target organs were removed for histopathology. Cytokine transcription and viral load were performed using real-time PCR. Serum cytokine levels were determined by ELISA, and T-cell markers by real-time PCR. RESULTS: DX (0.5-50 µM) inhibited MCMV plaque formation in vitro. However, in vivo, prophylactic DX treatment did not decrease viral load and prolonged hepatic proinflammatory cytokine transcription at days 3 and 5 post-infection, which corresponded with more severe histopathological changes observed in the liver. Significant CD8(+) T-cell marker suppression was seen, in accordance with DX-induced inhibition of lymphocyte proliferation observed in vitro. DX prolonged the recovery of MCMV-infected mice when given after infection was established. CONCLUSIONS: Despite promising MCMV inhibition in vitro, DX had no beneficial effect on MCMV disease in our model and paradoxically had adverse effects when administered prophylactically. The lack of correlation between in vitro activity and in vivo efficacy emphasizes the importance of selecting appropriate antiviral targets and of using animal models when testing new drugs.

Interleukin-10 repletion suppresses pro-inflammatory cytokines and decreases liver pathology without altering viral replication in murine cytomegalovirus (MCMV)-infected IL-10 knockout mice.

OBJECTIVE AND DESIGN: To determine the role of interleukin-10 (IL-10) in protecting against the deleterious pro-inflammatory cytokine response to murine cytomegalovirus (MCMV), we studied the impact of IL-10 repletion in MCMV-infected IL-10 knockout (KO) mice. MATERIALS AND METHODS: IL-10 KO mice were infected with a sub-lethal dose of MCMV and treated daily with 5 µg of mouse recombinant IL-10 (mrIL-10). Cytokine transcription, viral load, cytokine expression and liver histopathology were assessed in IL-10 treated and untreated mice. RESULTS: mrIL-10 repletion suppressed the exaggerated pro-inflammatory cytokine response observed in IL-10 KO mice (vs. control) both systemically and at the organ level, without affecting viral load. Levels of IFN-γ and TNF-α mRNA in livers of treated mice were ~50-70-fold lower than in untreated mice at day 5 post-infection (p ≤ 0.05). In spleens and sera, levels of IFN-γ and IL-6 were significantly lower in treated mice than in untreated mice at day 5-7 post-infection (p ≤ 0.05). IL-10 blunting of cytokine responses was accompanied by attenuation of inflammation in livers of treated mice. CONCLUSIONS: Repletion of IL-10 modulates the exaggerated pro-inflammatory cytokine responses that characterize IL-10 KO mice and protects against liver damage without altering viral load. IL-10 may be useful to control dysregulated pro-inflammatory cytokines responses during CMV infection.

Related to ubiquitin 1 and 2 are redundant and essential and regulate vegetative growth, auxin signaling, and ethylene production in Arabidopsis.

Related to Ubiquitin (RUB)/Nedd8 is a ubiquitin-like protein that covalently attaches to cullins, a subunit of the SCF (for Skp, Cdc53p/Cul1, and F-box protein) complex, an E3 ubiquitin ligase, and has been shown to be required for robust function of the complex. The effects of reducing protein levels for two Rub proteins, RUB1 and RUB2, were characterized in Arabidopsis thaliana. T-DNA insertional null lines homozygous at a single RUB-encoding locus were analyzed and found to have a wild-type phenotype. A double mutant was never recovered. More than one-quarter of the progeny from the self-fertilization of plants with a single functional RUB-encoding gene died as embryos at the two-cell stage. Outcrosses demonstrated reduced inheritance of the null allele from both the male and female parent. Hemigglutinin-tagged forms of RUB1 and RUB2 conjugate to the same cullin protein, CUL1, and produce the same conjugation pattern. To further understand the function of the RUB proteins, a construct designed to produce a double-stranded RUB1 mRNA was introduced into plants, and three lines with reduced levels of RUB1- and RUB2-encoding mRNA and RUB1/2 protein content were analyzed in detail. Mature plants were severely dwarfed, seedlings were insensitive to auxin in root assays, and dark-grown seedlings had a partial triple-response phenotype that was suppressed when seedlings were grown on ethylene perception or synthesis inhibitors. The dsrub lines produced threefold to fivefold more ethylene than the wild type. This study illustrates that RUB1 and RUB2 are genetically and biochemically redundant and demonstrates that RUB1/2 proteins are essential for early embryonic cell divisions and that they regulate diverse processes.