Role of Actin Microfilaments in Canine Distemper Virus Replication in Vero Cells

2004 ◽  
Vol 66 (4) ◽  
pp. 409-415 ◽  
Author(s):  
Hideo KATAYAMA ◽  
Masatoshi HORI ◽  
Koichi SATO ◽  
Masahiro KAJITA ◽  
Hiroshi OZAKI ◽  
...  
2006 ◽  
Vol 53 (6) ◽  
pp. 273-277 ◽  
Author(s):  
M. Kajita ◽  
H. Katayama ◽  
T. Murata ◽  
C. Kai ◽  
M. Hori ◽  
...  

Author(s):  
Yao Li ◽  
Li Yi ◽  
Sipeng Cheng ◽  
Yongshan Wang ◽  
Jiongjiong Wang ◽  
...  

Canine distemper virus (CDV) is the aetiological agent that causes canine distemper (CD). Currently, no antiviral drugs have been approved for CD treatment. A77 1726 is the active metabolite of the anti-rheumatoid arthritis (RA) drug leflunomide. It inhibits the activity of Janus kinases (JAKs) and dihydroorotate dehydrogenase (DHO-DHase), a rate-limiting enzyme in de novo pyrimidine nucleotide synthesis. A77 1726 also inhibits the activity of p70 S6 kinase (S6K1), a serine/threonine kinase that phosphorylates and activates carbamoyl-phosphate synthetase (CAD), a second rate-limiting enzyme in the de novo pathway of pyrimidine nucleotide synthesis. Our present study focuses on the ability of A77 1726 to inhibit CDV replication and its underlying mechanisms. Here we report that A77 1726 decreased the levels of the N and M proteins of CDV and lowered the virus titres in the conditioned media of CDV-infected Vero cells. CDV replication was not inhibited by Ruxolitinib (Rux), a JAK-specific inhibitor, but by brequinar sodium (BQR), a DHO-DHase-specific inhibitor, and PF-4708671, an S6K1-specific inhibitor. Addition of exogenous uridine, which restores intracellular pyrimidine nucleotide levels, blocked the antiviral activity of A77 1726, BQR and PF-4708671. A77 1726 and PF-4708671 inhibited the activity of S6K1 in CDV-infected Vero cells, as evidenced by the decreased levels of CAD and S6 phosphorylation. S6K1 knockdown suppressed CDV replication and enhanced the antiviral activity of A77 1726. These observations collectively suggest that the antiviral activity of A77 1726 against CDV is mediated by targeting pyrimidine nucleotide synthesis via inhibiting DHO-DHase activity and S6K1-mediated CAD activation.


2015 ◽  
Vol 90 (3) ◽  
pp. 1622-1637 ◽  
Author(s):  
Mojtaba Khosravi ◽  
Fanny Bringolf ◽  
Silvan Röthlisberger ◽  
Maria Bieringer ◽  
Jürgen Schneider-Schaulies ◽  
...  

ABSTRACTMeasles virus (MeV) and canine distemper virus (CDV) possess tetrameric attachment proteins (H) and trimeric fusion proteins, which cooperate with either SLAM or nectin 4 receptors to trigger membrane fusion for cell entry. While the MeV H-SLAM cocrystal structure revealed the binding interface, two distinct oligomeric H assemblies were also determined. In one of the conformations, two SLAM units were sandwiched between two discrete H head domains, thus spotlighting two binding interfaces (“front” and “back”). Here, we investigated the functional relevance of both interfaces in activating the CDV membrane fusion machinery. While alanine-scanning mutagenesis identified five critical regulatory residues in the front H-binding site of SLAM, the replacement of a conserved glutamate residue (E at position 123, replaced with A [E123A]) led to the most pronounced impact on fusion promotion. Intriguingly, while determination of the interaction of H with the receptor using soluble constructs revealed reduced binding for the identified SLAM mutants, no effect was recorded when physical interaction was investigated with the full-length counterparts of both molecules. Conversely, although mutagenesis of three strategically selected residues within the back H-binding site of SLAM did not substantially affect fusion triggering, nevertheless, the mutants weakened the H-SLAM interaction recorded with the membrane-anchored protein constructs. Collectively, our findings support a mode of binding between the attachment protein and the V domain of SLAM that is common to all morbilliviruses and suggest a major role of the SLAM residue E123, located at the front H-binding site, in triggering the fusion machinery. However, our data additionally support the hypothesis that other microdomain(s) of both glycoproteins (including the back H-binding site) might be required to achieve fully productive H-SLAM interactions.IMPORTANCEA complete understanding of the measles virus and canine distemper virus (CDV) cell entry molecular framework is still lacking, thus impeding the rational design of antivirals. Both viruses share many biological features that partially rely on the use of analogous Ig-like host cell receptors, namely, SLAM and nectin 4, for entering immune and epithelial cells, respectively. Here, we provide evidence that the mode of binding between the membrane-distal V domain of SLAM and the attachment protein (H) of morbilliviruses is very likely conserved. Moreover, although structural information revealed two discrete conformational states of H, one of the structures displayed two H-SLAM binding interfaces (“front” and “back”). Our data not only spotlight the front H-binding site of SLAM as the main determinant of membrane fusion promotion but suggest that the triggering efficiency of the viral entry machinery may rely on a local conformational change within the front H-SLAM interactive site rather than the binding affinity.


1992 ◽  
Vol 4 (3) ◽  
pp. 258-263 ◽  
Author(s):  
Max J. G. Appel ◽  
Susan Pearce-Kelling ◽  
Brian A. Summers

Optimal conditions for the isolation and growth of virulent canine distemper virus (CDV) in canine thymic and peripheral blood lymphocyte cultures were determined. Peak virus titers were seen from 3 to 6 days postinoculation of lymphocytes and depended on the multiplicity of infection. Dog lymphocytes were at least as susceptible as canine macrophages to infection with virulent CDV. Virus replication in lymphocytes resulted in higher virus titers than in dog lung macrophages. Peripheral blood lymphocytes (PBL) from CDV-immune dogs were as susceptible to CDV as were PBL from susceptible dogs.


2010 ◽  
Vol 30 (2) ◽  
pp. 139-144 ◽  
Author(s):  
Helen L. Del Puerto ◽  
Anilton C. Vasconcelos ◽  
Luciana Moro ◽  
Fabiana Alves ◽  
Gissandra F. Braz ◽  
...  

A quantitative real time polymerase chain reaction (PCR) revealed canine distemper virus presence in peripheral blood samples from asymptomatic and non vaccinated dogs. Samples from eleven domestic dogs with no signs of canine distemper and not vaccinated at the month of collection were used. Canine distemper virus vaccine samples in VERO cells were used as positive controls. RNA was isolated with Trizol®, and treated with a TURBO DNA-free kit. Primers were designed for canine distemper virus nucleocapsid protein coding region fragment amplification (84 bp). Canine b-actin (93 bp) was utilized as the endogenous control for normalization. Quantitative results of real time PCR generated by ABI Prism 7000 SDS Software showed that 54.5% of dogs with asymptomatic canine distemper were positive for canine distemper virus. Dissociation curves confirmed the specificity of the real time PCR fragments. This technique could detect even a few copies of viral RNA and identificate subclinically infected dogs providing accurate diagnosis of this disease at an early stage.


1985 ◽  
Vol 66 (1) ◽  
pp. 149-157 ◽  
Author(s):  
N. Hirayama ◽  
M. Senda ◽  
K. Kurata ◽  
Y. Yoshikawa ◽  
K. Yamanouchi

2018 ◽  
Vol 92 (17) ◽  
Author(s):  
Vishakha Tiwarekar ◽  
Julia Wohlfahrt ◽  
Markus Fehrholz ◽  
Claus-Jürgen Scholz ◽  
Susanne Kneitz ◽  
...  

ABSTRACTWe found earlier that ectopic expression of the cytidine deaminase APOBEC3G (A3G) in Vero cells inhibits measles virus (MV), respiratory syncytial virus, and mumps virus, while the mechanism of inhibition remained unclear. A microarray analysis revealed that in A3G-transduced Vero cells, several cellular transcripts were differentially expressed, suggesting that A3G regulates the expression of host factors. One of the most upregulated host cell factors, REDD1 (regulated in development and DNA damage response-1, also called DDIT4), reduced MV replication ∼10-fold upon overexpression in Vero cells. REDD1 is an endogenous inhibitor of mTORC1 (mammalian target of rapamycin complex-1), the central regulator of cellular metabolism. Interestingly, rapamycin reduced the MV replication similarly to REDD1 overexpression, while the combination of both did not lead to further inhibition, suggesting that the same pathway is affected. REDD1 silencing in A3G-expressing Vero cells abolished the inhibitory effect of A3G. In addition, silencing of A3G led to reduced REDD1 expression, confirming that its expression is regulated by A3G. In primary human peripheral blood lymphocytes (PBL), expression of A3G and REDD1 was found to be stimulated by phytohemagglutinin (PHA) and interleukin-2. Small interfering RNA (siRNA)-mediated depletion of A3G in PHA-stimulated PBL reduced REDD1 expression and increased viral titers, which corroborates our findings in Vero cells. Silencing of REDD1 also increased viral titers, confirming the antiviral role of REDD1. Finally, pharmacological inhibition of mTORC1 by rapamycin in PHA-stimulated PBL reduced viral replication to the level found in unstimulated lymphocytes, indicating that mTORC1 activity supports MV replication as a proviral host factor.IMPORTANCEKnowledge about host factors supporting or restricting virus replication is required for a deeper understanding of virus-cell interactions and may eventually provide the basis for therapeutic intervention. This work was undertaken predominantly to explain the mechanism of A3G-mediated inhibition of MV, a negative-strand RNA virus that is not affected by the deaminase activity of A3G acting on single-stranded DNA. We found that A3G regulates the expression of several cellular proteins, which influences the capacity of the host cell to replicate MV. One of these, REDD1, which modulates the cellular metabolism in a central position by regulating the kinase complex mTORC1, was identified as the major cellular factor impairing MV replication. These findings show interesting aspects of the function of A3G and the dependence of the MV replication on the metabolic state of the cell. Interestingly, pharmacological inhibition of mTORC1 can be utilized to inhibit MV replication in Vero cells and primary human peripheral blood lymphocytes.


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