scholarly journals Inhibition of dengue virus replication by mycophenolic acid and ribavirin

2006 ◽  
Vol 87 (7) ◽  
pp. 1947-1952 ◽  
Author(s):  
Ratree Takhampunya ◽  
Sukathida Ubol ◽  
Huo-Shu Houng ◽  
Craig E. Cameron ◽  
Radhakrishnan Padmanabhan
Keyword(s):  
Mycophenolic Acid ◽  
Viral Rna ◽  
Guanine Nucleotide ◽  
Inosine Monophosphate Dehydrogenase ◽  
Human Pathogens ◽  
Rt Pcr ◽  
Rna Translation ◽  
The Family ◽  
Viral Replicase

Dengue viruses (DEN), mosquito-borne members of the family Flaviviridae, are human pathogens of global significance. The effects of mycophenolic acid (MPA) and ribavirin (RBV) on DEN replication in monkey kidney (LLC-MK2) cells were examined. MPA (IC50=0.4±0.3 μM) and RBV (IC50=50.9±18 μM) inhibited DEN2 replication. Quantitative real-time RT-PCR of viral RNA and plaque assays of virions from DEN2-infected and MPA (10 μM)- and RBV (⩾200 μM)-treated cells showed a fivefold increase in defective viral RNA production by cells treated with each drug. Moreover, a dramatic reduction of intracellular viral replicase activity was seen by in vitro replicase assays. Guanosine reversed the inhibition of these compounds, suggesting that one mode of antiviral action of MPA and RBV is by inhibition of inosine monophosphate dehydrogenase and thereby depletion of the intracellular GTP pool. In addition, RBV may act by competing with guanine-nucleotide precursors in viral RNA translation, replication and 5′ capping.

scholarly journals Multiple Types of Novel Enteric Bopiviruses (Picornaviridae) with the Possibility of Interspecies Transmission Identified from Cloven-Hoofed Domestic Livestock (Ovine, Caprine and Bovine) in Hungary

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 66
Author(s):  
Zoltán László ◽  
Péter Pankovics ◽  
Gábor Reuter ◽  
Attila Cságola ◽  
Ádám Bálint ◽  
...  
Keyword(s):  
Novel Species ◽  
Phylogenetic Analyses ◽  
Interspecies Transmission ◽  
Background Information ◽  
Type Ii ◽  
Rt Pcr ◽  
Faecal Samples ◽  
The Family ◽  
Domestic Livestock

Most picornaviruses of the family Picornaviridae are relatively well known, but there are certain “neglected” genera like Bopivirus, containing a single uncharacterised sequence (bopivirus A1, KM589358) with very limited background information. In this study, three novel picornaviruses provisionally called ovipi-, gopi- and bopivirus/Hun (MW298057-MW298059) from enteric samples of asymptomatic ovine, caprine and bovine respectively, were determined using RT-PCR and dye-terminator sequencing techniques. These monophyletic viruses share the same type II-like IRES, NPGP-type 2A, similar genome layout (4-3-4) and cre-localisations. Culture attempts of the study viruses, using six different cell lines, yielded no evidence of viral growth in vitro. Genomic and phylogenetic analyses show that bopivirus/Hun of bovine belongs to the species Bopivirus A, while the closely related ovine-origin ovipi- and caprine-origin gopivirus could belong to a novel species “Bopivirus B” in the genus Bopivirus. Epidemiological investigation of N = 269 faecal samples of livestock (ovine, caprine, bovine, swine and rabbit) from different farms in Hungary showed that bopiviruses were most prevalent among <12-month-old ovine, caprine and bovine, but undetectable in swine and rabbit. VP1 capsid-based phylogenetic analyses revealed the presence of multiple lineages/genotypes, including closely related ovine/caprine strains, suggesting the possibility of ovine–caprine interspecies transmission of certain bopiviruses.

A phase I trial of AVN944 in patients with advanced hematologic malignancies

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 14026-14026 ◽  
Author(s):  
R. B. Klisovic ◽  
G. Tricot ◽  
S. Coutre ◽  
T. Kovacsovics ◽  
F. Giles ◽  
...  
Keyword(s):  
Gene Expression ◽  
Phase I ◽  
Hematologic Malignancies ◽  
Guanine Nucleotide ◽  
Inosine Monophosphate Dehydrogenase ◽  
Open Label ◽  
Serious Adverse Events ◽  
Peripheral Blood Mononuclear ◽  
Nucleotide Synthesis

14026 Background: AVN-944 is an inhibitor of inosine monophosphate dehydrogenase (IMPDH), an enzyme that catalyzes the rate- limiting step in guanine nucleotide synthesis, and induces apoptosis in malignant hematopoietic cell lines in vitro. Methods: This phase I study employed open-label dose escalations in patients (pts) with relapsed, refractory hematologic cancers with safety, pharmacokinetic (PK), pharmacodynamic, & efficacy endpoints. Between 12/05 and 1/07 a total of 70 cycles of AVN944 at 25 (7pts), 50 (6pts), 75 (7pts), 100 (7pts) or 125 mg (3pts) b.i.d. orally X 21d every 28d were administered to 30 pts with AML (12), ALL (2), CLL (3), and multiple myeloma (13). Peripheral blood mononuclear cell (PBMC) or leukemic blast samples were obtained from all pts pre and post-receiving AVN944 to determine effects on GTP pools, IMPDH activity, and to correlate these changes to response in a 32-gene set that relates directly to cellular pathways dependent upon guanine nucleotide biosynthesis. Results: Pharmacokinetics were dose proportional with mean Tmax=1 hour, T1/2=1.5 hours, Cmax=2800 ng/ml and AUC=7228 hr.ng/ml at the 100 mg b.i.d. dose. Toxicities were generally mild-moderate and/or not attributed to AVN944. Twelve serious adverse events (SAEs) occurred in 8 pts; 7 of 8 had AML. No SAEs was attributed to AVN944. DLT was not seen. No protocol defined responses were seen. Twelve of 24 assessable pts had stable disease of 2 to 10 months duration. Changes in the gene expression set correlated with disease stability. Conclusions: AVN944 is well tolerated with oral b.i.d. dosing. Stabilization of disease was observed in half of the pts. Gene expression correlated with stable versus progressive disease. [Table: see text]

scholarly journals Hantavirus N Protein Exhibits Genus-Specific Recognition of the Viral RNA Panhandle

2006 ◽  
Vol 80 (22) ◽  
pp. 11283-11292 ◽  
Author(s):  
M. A. Mir ◽  
B. Brown ◽  
B. Hjelle ◽  
W. A. Duran ◽  
A. T. Panganiban
Keyword(s):  
Viral Rna ◽  
Genomic Rna ◽  
N Protein ◽  
High Affinity ◽  
The Andes ◽  
The Family ◽  
Viral Genomic Rna ◽  
Negative Sense

ABSTRACT A key genomic characteristic that helps define Hantavirus as a genus of the family Bunyaviridae is the presence of distinctive terminal complementary nucleotides that promote the folding of the viral genomic segments into “panhandle” hairpin structures. The hantavirus nucleocapsid protein (N protein), which is encoded by the smallest of the three negative-sense genomic RNA segments, undergoes in vivo and in vitro trimerization. Trimeric hantavirus N protein specifically recognizes the panhandle structure formed by complementary base sequence of 5′ and 3′ ends of viral genomic RNA. N protein trimers from the Andes, Puumala, Prospect Hill, Seoul, and Sin Nombre viruses recognize their individual homologous panhandles as well as other hantavirus panhandles with high affinity. In contrast, these hantavirus N proteins bind with markedly reduced affinity to the panhandles from the genera Bunyavirus, Tospovirus, and Phlebovirus or Nairovirus. Interactions between most hantavirus N and heterologous hantavirus viral RNA panhandles are mediated by the nine terminal conserved nucleotides of the panhandle, whereas Sin Nombre virus N requires the first 23 nucleotides for high-affinity binding. Trimeric hantavirus N complexes undergo a prominent conformational change while interacting with panhandles from members of the genus Hantavirus but not while interacting with panhandles from viruses of other genera of the family Bunyaviridae. These data indicate that high-affinity interactions between trimeric N and hantavirus panhandles are conserved within the genus Hantavirus.

scholarly journals Establishment of an antiviral assay system and identification of severe fever with thrombocytopenia syndrome virus inhibitors

2017 ◽  
Vol 25 (3) ◽  
pp. 83-89 ◽  
Author(s):  
Masanori Baba ◽  
Masaaki Toyama ◽  
Norikazu Sakakibara ◽  
Mika Okamoto ◽  
Naomichi Arima ◽  
...  
Keyword(s):  
Antiviral Agents ◽  
Vero Cells ◽  
Assay System ◽  
Viral Rna ◽  
University Hospital ◽  
Selective Inhibitors ◽  
Reverse Transcription Pcr ◽  
The Family ◽  
Severe Fever

Aims Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease. SFTS is epidemic in Asia, and its fatality rate is around 30% in Japan. The causative virus severe fever with thrombocytopenia syndrome virus (SFTSV) is a phlebovirus of the family Phenuiviridae (the order Bunyavirales). Although effective treatments are required, there are no antiviral agents currently approved for clinical use. Ribavirin and favipiravir were examined for their anti-SFTSV activity and found to be selective inhibitors of SFTSV replication in vitro. However, their activity was not sufficient. Therefore, it is mandatory to identify novel compounds active against SFTSV. To this end, we have established a safe and rapid assay system for screening selective inhibitors of SFTSV. Methods The virus was isolated from SFTS patients treated in Kagoshima University Hospital. Vero cells were infected with SFTSV and incubated in the presence of various concentrations of test compounds. After three days, the cells were examined for their intracellular viral RNA levels by real-time reverse transcription-PCR without extracting viral RNA. The cytotoxicity of test compounds was determined by a tetrazolium dye method. Results Among the test compounds, the antimalarial agent amodiaquine was identified as a selective inhibitor of SFTSV replication. Its 50% effective concentration (EC50) and cytotoxic concentration (CC50) were 19.1 ± 5.1 and >100 µM, respectively. The EC50 value of amodiaquine was comparable to those of ribavirin and favipiravir. Conclusion Amodiaquine is considered to be a promising lead of novel anti-SFTSV agents, and evaluating the anti-SFTSV activity of its derivatives is in progress.

scholarly journals Viral RNA switch mediates the dynamic control of flavivirus replicase recruitment by genome cyclization

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Zhong-Yu Liu ◽  
Xiao-Feng Li ◽  
Tao Jiang ◽  
Yong-Qiang Deng ◽  
Qing Ye ◽  
...  
Keyword(s):  
Virus Replication ◽  
Rna Synthesis ◽  
Rna Viruses ◽  
Rna Virus ◽  
Dynamic Control ◽  
Viral Rna ◽  
Human Pathogens ◽  
Cis Acting ◽  
Viral Replicase ◽  
Rna Switch

Viral replicase recruitment and long-range RNA interactions are essential for RNA virus replication, yet the mechanism of their interplay remains elusive. Flaviviruses include numerous important human pathogens, e.g., dengue virus (DENV) and Zika virus (ZIKV). Here, we revealed a highly conserved, conformation-tunable cis-acting element named 5′-UAR-flanking stem (UFS) in the flavivirus genomic 5′ terminus. We demonstrated that the UFS was critical for efficient NS5 recruitment and viral RNA synthesis in different flaviviruses. Interestingly, stabilization of the DENV UFS impaired both genome cyclization and vRNA replication. Moreover, the UFS unwound in response to genome cyclization, leading to the decreased affinity of NS5 for the viral 5′ end. Thus, we propose that the UFS is switched by genome cyclization to regulate dynamic RdRp binding for vRNA replication. This study demonstrates that the UFS enables communication between flavivirus genome cyclization and RdRp recruitment, highlighting the presence of switch-like mechanisms among RNA viruses.

scholarly journals Assessment of Mycophenolic Acid-induced Immunosuppression: A New Approach

2000 ◽  
Vol 46 (9) ◽  
pp. 1376-1383 ◽  
Author(s):  
Olga Millan ◽  
Federic Oppenheimer ◽  
Merce Brunet ◽  
Jordi Vilardell ◽  
Isabel Rojo ◽  
...  
Keyword(s):  
Cell Line ◽  
Mycophenolic Acid ◽  
Mononuclear Cells ◽  
Renal Transplant Recipients ◽  
Inosine Monophosphate Dehydrogenase ◽  
Peripheral Blood Mononuclear ◽  
Impdh Activity ◽  
Inhibitory Capacity

Abstract Background: Mycophenolic acid (MPA), a metabolite of mycophenolate mofetil (MMF), is an immunosuppressive agent that inhibits inosine monophosphate dehydrogenase (IMPDH), a key enzyme in the ex novo synthesis of GTP. We measured IMPDH activity in peripheral blood mononuclear cells (PBMCs) from MMF-treated patients to evaluate the efficacy of MMF in individual patients. Methods: IMPDH activity was measured by 3H released from [2,8-3H]IMP that had been formed in the cells from added [2,8-3H]hypoxanthine in PBMCs of 35 renal transplant recipients treated with cyclosporin A and corticoids plus MMF: 2 g (n = 10), 1.5 g (n = 7), 1 g (n = 10), or 0 g (n = 8) per day. An alternative method, based on the capacity of the patients’ sera to inhibit spontaneous proliferation of the CEM cell line, was also analyzed. Results: The IMPDH activity of PBMCs in transplanted patients was highly variable. For the method based on CEM cell line proliferation: (a) cell proliferation was inhibited only in MMF-treated patients; (b) there was a clear postdose increase in inhibition; (c) inhibition was not affected by other immunosuppressants in vitro or in vivo; (d) inhibition from predose to predose sample was correlated; and (e) when the MMF dosage was &lt;20 mg · kg−1 · day−1, two groups of patients were identified, one that maintained a high inhibitory capacity in all dose intervals, and one with periods of low inhibitory capacity. Conclusions: Measurement of the inhibition of CEM cell line proliferation by sera from MMF-treated patients may be useful for evaluating the relative efficacy of MMF treatment in individual patients, especially those receiving low doses of MMF.

scholarly journals Staufen1 Protein Participates Positively in the Viral RNA Replication of Enterovirus 71

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 142 ◽  
Author(s):  
Young-Mao Chen ◽  
Bo-Ting Ou ◽  
Chao-Ying Chen ◽  
Han-Hsiang Chan ◽  
Chih-Jung Chen ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Virus ◽  
Rna Stability ◽  
Enterovirus 71 ◽  
Viral Rna ◽  
Viral Translation ◽  
Rna Translation ◽  
Rna Accumulation

The double-stranded RNA-binding protein Staufen1 (Stau1) has multiple functions during RNA virus infection. In this study, we investigated the role of Stau1 in viral translation by using a combination of enterovirus 71 (EV-A71) infection, RNA reporter transfection, and in vitro functional and biochemical assays. We demonstrated that Stau1 specifically binds to the 5′-untranslated region of EV-A71 viral RNA. The RNA-binding domain 2-3 of Stau1 is responsible for this binding ability. Subsequently, we created a Stau1 knockout cell line using the CRISPR/Cas9 approach to further characterize the functional role of Stau1’s interaction with viral RNA in the EV-A71-infected cells. Both the viral RNA accumulation and viral protein expression were downregulated in the Stau1 knockout cells compared with the wild-type naïve cells. Moreover, dysregulation of viral RNA translation was observed in the Stau1 knockout cells using ribosome fractionation assay, and a reduced RNA stability of 5′-UTR of the EV-A71 was also identified using an RNA stability assay, which indicated that Stau1 has a role in facilitating viral translation during EV-A71 infection. In conclusion, we determined the functional relevance of Stau1 in the EV-A71 infection cycle and herein describe the mechanism of Stau1 participation in viral RNA translation through its interaction with viral RNA. Our results suggest that Stau1 is an important host factor involved in viral translation and influential early in the EV-A71 replication cycle.

scholarly journals Mutagenic analysis of Potato Virus X movement protein (TGBp1) and the coat protein (CP): in vitro TGBp1–CP binding and viral RNA translation activation

2007 ◽  
Vol 0 (0) ◽  
pp. 071127144754003-??? ◽  
Author(s):  
OLGA ZAYAKINA ◽  
MARINA ARKHIPENKO ◽  
STANISLAV KOZLOVSKY ◽  
NIKOLAI NIKITIN ◽  
ALEXANDER SMIRNOV ◽  
...  
Keyword(s):  
Coat Protein ◽  
Potato Virus ◽  
Movement Protein ◽  
Potato Virus X ◽  
Viral Rna ◽  
Rna Translation

scholarly journals Modulation of Dengue Virus Infection in Human Cells by Alpha, Beta, and Gamma Interferons

2000 ◽  
Vol 74 (11) ◽  
pp. 4957-4966 ◽  
Author(s):  
Michael S. Diamond ◽  
T. Guy Roberts ◽  
Dianna Edgil ◽  
Betty Lu ◽  
Joel Ernst ◽  
...  
Keyword(s):  
Dengue Virus ◽  
Plaque Assay ◽  
Cell Types ◽  
Viral Rna ◽  
Rt Pcr ◽  
Cell Infection ◽  
Variable Effect ◽  
Dependent Cell ◽  
Low Passage

ABSTRACT A role for interferon (IFN) in modulating infection by dengue virus (DV) has been suggested by studies in DV-infected patients and IFN receptor-deficient mice. To address how IFN modulates DV type 2 infection, we have assayed IFN-α, -β, and -γ for the ability to enhance or diminish antibody-independent and antibody-dependent cell infection using a competitive, asymmetric reverse transcriptase-mediated PCR (RT-PCR) assay that quantitates positive and negative strands of viral RNA, a flow cytometric assay that measures viral antigen, and a plaque assay that analyzes virion production. Our data suggest that IFN-α and -β protect cells against DV infection in vitro. Treatment of hepatoma cells with IFN-α or -β decreases viral RNA levels greater than 1,000-fold, the percentage of cells infected 90 to 95%, and the amount of infectious virus secreted 150- to 100,000-fold. These results have been reproduced with several cell types and viral strains, including low-passage isolates. In contrast, IFN-γ has a more variable effect depending on the cell type and pathway of infection. Quantitative RT-PCR experiments indicate that IFN inhibits DV infection by preventing the accumulation of negative-strand viral RNA.

Sign in / Sign up

Export Citation Format

Share Document