scholarly journals Transition from Acute to Persistent Theiler's Virus Infection Requires Active Viral Replication That Drives Proinflammatory Cytokine Expression and Chronic Demyelinating Disease

2004 ◽  
Vol 78 (22) ◽  
pp. 12480-12488 ◽  
Author(s):  
Mark Trottier ◽  
Brian P. Schlitt ◽  
Aisha Y. Kung ◽  
Howard L. Lipton
Keyword(s):  
Spinal Cord ◽  
Viral Replication ◽  
Proinflammatory Cytokine ◽  
Viral Genome ◽  
Demyelinating Disease ◽  
Rna Replication ◽  
Viral Rna ◽  
Mrna Levels ◽  
Active Viral Replication ◽  
The Brain

ABSTRACT The dynamics of Theiler's murine encephalomyelitis virus (TMEV) RNA replication in the central nervous systems of susceptible and resistant strains of mice were examined by quantitative real-time reverse transcription-PCR and were found to correlate with host immune responses. During the acute phase of infection in both susceptible and resistant mice, levels of viral replication were high in the brain and brain stem, while levels of viral genome equivalents were 10- to 100-fold lower in the spinal cord. In the brain, viral RNA replication decreased after a peak at 5 days postinfection (p.i.), in parallel with the appearance of virus-specific antibody responses; however, by 15 days p.i., viral RNA levels began to increase in the spinal cords of susceptible mice. During the transition to and the persistent phase of infection, the numbers of viral genome equivalents in the spinal cord varied substantially for individual mice, but high levels were consistently associated with high levels of proinflammatory Th1 cytokine and chemokine mRNAs. Moreover, a large number of viral genome equivalents and high proinflammatory cytokine mRNA levels in spinal cords were only observed for susceptible SJL/J mice who developed demyelinating disease. These results suggest that TMEV persistence requires active viral replication beginning about day 11 p.i. and that active viral replication with high viral genome loads leads to increased levels of Th1 cytokines that drive disease progression in infected mice.

scholarly journals Human Choline Kinase-α Promotes Hepatitis C Virus RNA Replication through Modulation of Membranous Viral Replication Complex Formation

2016 ◽  
Vol 90 (20) ◽  
pp. 9075-9095 ◽  
Author(s):  
Mun-Teng Wong ◽  
Steve S. Chen
Keyword(s):  
Viral Replication ◽  
Rna Replication ◽  
Hcv Infection ◽  
Viral Rna ◽  
Choline Kinase ◽  
Replication Complex ◽  
Active Viral Replication ◽  
Infected Cells ◽  
Viral Replication Complex ◽  
Replication Site

ABSTRACTHepatitis C virus (HCV) infection reorganizes cellular membranes to create an active viral replication site named the membranous web (MW). The role that human choline kinase-α (hCKα) plays in HCV replication remains elusive. Here, we first showed that hCKα activity, not the CDP-choline pathway, promoted viral RNA replication. Confocal microscopy and subcellular fractionation of HCV-infected cells revealed that a small fraction of hCKα colocalized with the viral replication complex (RC) on the endoplasmic reticulum (ER) and that HCV infection increased hCKα localization to the ER. In the pTM-NS3-NS5B model, NS3-NS5B expression increased the localization of the wild-type, not the inactive D288A mutant, hCKα on the ER, and hCKα activity was required for effective trafficking of hCKα and NS5A to the ER. Coimmunoprecipitation showed that hCKα was recruited onto the viral RC presumably through its binding to NS5A domain 1 (D1). hCKα silencing or treatment with CK37, an hCKα activity inhibitor, abolished HCV-induced MW formation. In addition, hCKα depletion hindered NS5A localization on the ER, interfered with NS5A and NS5B colocalization, and mitigated NS5A-NS5B interactions but had no apparent effect on NS5A-NS4B and NS4B-NS5B interactions. Nevertheless, hCKα activity was not essential for the binding of NS5A to hCKα or NS5B. These findings demonstrate that hCKα forms a complex with NS5A and that hCKα activity enhances the targeting of the complex to the ER, where hCKα protein, not activity, mediates NS5A binding to NS5B, thereby promoting functional membranous viral RC assembly and viral RNA replication.IMPORTANCEHCV infection reorganizes the cellular membrane to create an active viral replication site named the membranous web (MW). Here, we report that human choline kinase-α (hCKα) acts as an essential host factor for HCV RNA replication. A fraction of hCKα colocalizes with the viral replication complex (RC) on the endoplasmic reticulum (ER) in HCV-infected cells. NS3-NS5B expression increases ER localization of wild-type, but not D288A mutant, hCKα, and hCKα activity facilitates the transport of itself and NS5A to the ER. Silencing or inactivation of hCKα abrogates MW formation. Moreover, hCKα is recruited by NS5A independent of hCKα activity, presumably through binding to NS5A D1. hCKα activity then mediates the ER targeting of the hCKα-NS5A complex. On the ER membrane, hCKα protein,per se, induces NS5A binding to NS5B, thereby promoting membranous RC formation and viral RNA replication. Our study may benefit the development of hCKα-targeted anti-HCV therapeutics.

Abstract 229: Determination of Phase-specific Biomarkers of Viral Myocarditis Induced by Theiler’s virus Using Multivariate Analyses of Viral Genome, Troponin, Transcriptome and Echocardiography Data

2013 ◽  
Vol 113 (suppl_1) ◽  
Author(s):  
Eiichiro Kawai ◽  
Seiichi Omura ◽  
Fumitaka Sato ◽  
Nicholas E Martinez ◽  
Viromi Fernando ◽  
...  
Keyword(s):  
Immune Responses ◽  
Viral Replication ◽  
Microarray Data ◽  
Viral Genome ◽  
Troponin I ◽  
Multivariate Analyses ◽  
Viral Myocarditis ◽  
Myocardial Damage ◽  
Heart Tissue ◽  
Viral Rna

Viral myocarditis has been proposed to be initiated by viral replication in the heart (acute phase), followed by immune-mediated damage (subacute phase), where each phase requires anti-viral and immunomodulatory treatments, respectively. There are no specific biomarkers to distinguish acute from subacute phases of myocarditis while serum troponin, echocardiography, and myocardial biopsy data have been used for diagnosis clinically. To determine the phase-specific biomarkers, we used a mouse model for myocarditis induced by Theiler’s murine encephalomyelitis virus (TMEV), which belongs to the genus Cardiovirus, the family Picornaviridae. We conducted multivariate analyses of viral genome, serum cardiac troponin I, echocardiography, histology, and transcriptome using microarray data of the heart tissue harvested on 4 (acute) and 7 (subacute) days post infection (dpi). The level of viral RNA semi-quantified by RT-PCR was 10-fold higher on 4 dpi (ΔCt = 2.5×10-2 ± 4.9×10-3) than 7 dpi (ΔCt = 2.6×10-3 ± 3.0×10-4) (P < 0.05). Serum troponin was undetectable in 4 of 10 mice on 4 dpi and only in 1 of 10 mice on 7 dpi; the serum troponin levels (ng/ml) on 4 dpi (42.9 ± 15.6) were significantly lower than 7 dpi (249.9 ± 62.8) (P < 0.05). The levels of viral RNA and troponin were strongly correlated on 4 dpi (r = 0.79, P < 0.05), but not 7 dpi (P = 0.12), suggesting that viral replication could be a major cause of myocardial damage only on 4 dpi. We found multiple high intensity cardiac lesions using echocardiography with histological myocarditis on 7 dpi, but not 4 dpi. Transcriptome analyses of microarray data showed upregulation of genes associated with innate immune responses in samples from 4 and 7 dpi, compared with controls. Samples from 7 dpi showed upregulation of genes associated with T, B, and antigen presenting cells and downregulation of cardiac myosin-related genes (Myl4, Myl7, and Mybphl), compared with 4 dpi, suggesting that acquired immune responses contribute to cardiomyocyte damage on 7 dpi. In summary, the chronological order of emergence of biomarker candidates was 1) viral genome and innate immunity, 2) troponin, and 3) acquired immunity and echo and histological changes.

scholarly journals BothcisandtransActivities of Foot-and-Mouth Disease Virus 3D Polymerase Are Essential for Viral RNA Replication

2016 ◽  
Vol 90 (15) ◽  
pp. 6864-6883 ◽  
Author(s):  
Morgan R. Herod ◽  
Cristina Ferrer-Orta ◽  
Eleni-Anna Loundras ◽  
Joseph C. Ward ◽  
Nuria Verdaguer ◽  
...  
Keyword(s):  
Disease Virus ◽  
Viral Genome ◽  
Foot And Mouth Disease ◽  
Rna Replication ◽  
Mouth Disease ◽  
Viral Rna ◽  
Genome Replication ◽  
Replication Complex ◽  
Mouth Disease Virus ◽  
Foot And Mouth

ABSTRACTThePicornaviridaeis a large family of positive-sense RNA viruses that contains numerous human and animal pathogens, including foot-and-mouth disease virus (FMDV). The picornavirus replication complex comprises a coordinated network of protein-protein and protein-RNA interactions involving multiple viral and host-cellular factors. Many of the proteins within the complex possess multiple roles in viral RNA replication, some of which can be provided intrans(i.e., via expression from a separate RNA molecule), while others are required incis(i.e., expressed from the template RNA molecule).In vitrostudies have suggested that multiple copies of the RNA-dependent RNA polymerase (RdRp) 3D are involved in the viral replication complex. However, it is not clear whether all these molecules are catalytically active or what other function(s) they provide. In this study, we aimed to distinguish between catalytically active 3D molecules and those that build a replication complex. We report a novel nonenzymaticcis-acting function of 3D that is essential for viral-genome replication. Using an FMDV replicon in complementation experiments, our data demonstrate that thiscis-acting role of 3D is distinct from the catalytic activity, which is predominantlytransacting. Immunofluorescence studies suggest that bothcis- andtrans-acting 3D molecules localize to the same cellular compartment. However, our genetic and structural data suggest that 3D interacts inciswith RNA stem-loops that are essential for viral RNA replication. This study identifies a previously undescribed aspect of picornavirus replication complex structure-function and an important methodology for probing such interactions further.IMPORTANCEFoot-and-mouth disease virus (FMDV) is an important animal pathogen responsible for foot-and-mouth disease. The disease is endemic in many parts of the world with outbreaks within livestock resulting in major economic losses. Propagation of the viral genome occurs within replication complexes, and understanding this process can facilitate the development of novel therapeutic strategies. Many of the nonstructural proteins involved in replication possess multiple functions in the viral life cycle, some of which can be supplied to the replication complex from a separate genome (i.e., intrans) while others must originate from the template (i.e., incis). Here, we present an analysis ofcisandtransactivities of the RNA-dependent RNA polymerase 3D. We demonstrate a novelcis-acting role of 3D in replication. Our data suggest that this role is distinct from its enzymatic functions and requires interaction with the viral genome. Our data further the understanding of genome replication of this important pathogen.

scholarly journals The induced dose of experimental autoimmune encephalomyelitis was not determinant and proportional to histopathological findings

2021 ◽  
Vol 31 (Supplement_2) ◽  
Author(s):  
Maiara Carolina Perussolo ◽  
Bassam Felipe Mogharbel ◽  
Lucia de Noronha ◽  
Katherine Athayde Teixeira de Carvalho
Keyword(s):  
Spinal Cord ◽  
Experimental Autoimmune Encephalomyelitis ◽  
Demyelinating Disease ◽  
Clinical Signs ◽  
Signs And Symptoms ◽  
Control Group ◽  
Autoimmune Encephalomyelitis ◽  
Histopathological Findings ◽  
The Brain ◽  
Experimental Autoimmune

Abstract Background Multiple sclerosis (MS) is an autoimmune disease of the central nervous system, characterized as an inflammatory demyelinating disease. It presents a diversity of neurologic signs and symptoms as well the incapacities. Since the need for advances in MS treatment, many studies are for new therapeutic technologies, mainly through using preclinical models as experimental autoimmune encephalomyelitis (EAE). This study aimed to observe and analyze the development in Lewis rats-induced model of EAE. Methods It was used 23 females of Rattus norvegicus, from 6 to 8 weeks, weighing around 170 g. Of 23 rats, 19 underwent EAE induction distributed in six groups to establish the evolution of clinical signs. B. pertussis toxin (PTX) doses were 200, 250, 300, 350–400 ng, and four animals as the control group. The animals had weight and scores analyzed daily, starting seven and ending 24 days after induction. Then, all animals were euthanized, and the brain and spinal cord were collected for histopathological analyses. Results The results showed that the dose of 250 ng of PTX induced de higher score and weight reduction. All groups who received the PTX demonstrated histopathological findings. Those characterized as leukocyte infiltration, activation of microglia and astrocytes, and demyelinated plaques in the brain. In the spinal cord, the loosening of the myelinated fibers was observed by increasing the axonal space in all tested doses of PTX. Conclusions EAE was not dose-dependent. Histopathological findings do not proportionally related to clinical signs, as in human patients with MS.

scholarly journals Noise-induced bistability in the quasineutral coexistence of viral RNA under different replication modes

2018 ◽  
Author(s):  
Josep Sardanyés ◽  
Andreu Arderiu ◽  
Santiago F. Elena ◽  
Tomás Alarcón
Keyword(s):  
Viral Replication ◽  
Evolutionary Dynamics ◽  
Rna Viruses ◽  
Initial Conditions ◽  
Rna Replication ◽  
Viral Rna ◽  
Stochastic Simulations ◽  
Strong Impact ◽  
Deterministic Models ◽  
The Impact

Evolutionary and dynamical investigations on real viral populations indicate that RNA replication can range between two extremes given by so-called stamping machine replication (SMR) and geometric replication (GR). The impact of asymmetries in replication for single-stranded, (+) sense RNA viruses has been up to now studied with deterministic models. However, viral replication should be better described by including stochasticity, since the cell infection process is typically initiated with a very small number of RNA macromolecules, and thus largely influenced by intrinsic noise. Under appropriate conditions, deterministic theoretical descriptions of viral RNA replication predict a quasineutral coexistence scenario, with a line of fixed points involving different strands’ equilibrium ratios depending on the initial conditions. Recent research on the quasineutral coexistence in two competing populations reveals that stochastic fluctuations fundamentally alters the mean-field scenario, and one of the two species outcompetes the other one. In this manuscript we study this phenomenon for RNA viral replication modes by means of stochastic simulations and a diffusion approximation. Our results reveal that noise has a strong impact on the amplification of viral RNA, also causing the emergence of noise-induced bistability. We provide analytical criteria for the dominance of (+) sense strands depending on the initial populations on the line of equilibria, which are in agreement with direct stochastic simulation results. The biological implications of this noise-driven mechanism are discussed within the framework of the evolutionary dynamics of RNA viruses with different modes of replication.

scholarly journals Jacques Jean Lhermitte and the syndrome of peduncular hallucinosis

2019 ◽  
Vol 47 (3) ◽  
pp. E9 ◽  
Author(s):  
Jennifer A. Kosty ◽  
Juan Mejia-Munne ◽  
Rimal Dossani ◽  
Amey Savardekar ◽  
Bharat Guthikonda
Keyword(s):  
Spinal Cord ◽  
Demyelinating Disease ◽  
Historical Review ◽  
Neurosurgical Procedures ◽  
Visual Hallucinations ◽  
Electrical Shock ◽  
Peduncular Hallucinosis ◽  
The Mind ◽  
The Relationship ◽  
The Brain

Jacques Jean Lhermitte (1877–1959) was among the most accomplished neurologists of the 20th century. In addition to working as a clinician and instructor, he authored more than 800 papers and 16 books on neurology, neuropathology, psychiatry, and mystical phenomena. In addition to the well-known “Lhermitte’s sign,” an electrical shock–like sensation caused by spinal cord irritation in demyelinating disease, Lhermitte was a pioneer in the study of the relationship between the physical substance of the brain and the experience of the mind. A fascinating example of this is the syndrome of peduncular hallucinosis, characterized by vivid visual hallucinations occurring in fully lucid patients. This syndrome, which was initially described as the result of a midbrain insult, also may occur with injury to the thalamus or pons. It has been reported as a presenting symptom of various tumors and as a complication of neurosurgical procedures. Here, the authors review the life of Lhermitte and provide a historical review of the syndrome of peduncular hallucinosis.

scholarly journals Uncoupled Expression of p33 and p92 Permits Amplification of Tomato Bushy Stunt Virus RNAs

1998 ◽  
Vol 72 (7) ◽  
pp. 5845-5851 ◽  
Author(s):  
Sara K. Oster ◽  
Baodong Wu ◽  
K. Andrew White
Keyword(s):  
Viral Genome ◽  
Stop Codon ◽  
Rna Virus ◽  
Rna Replication ◽  
Tomato Bushy Stunt Virus ◽  
Viral Rna ◽  
Rna Amplification ◽  
Viral Rnas ◽  
Reading Frame ◽  
Translational Enhancer

ABSTRACT Tomato bushy stunt virus (TBSV) is a plus-sense RNA virus which encodes a 33-kDa protein in its 5′-most open reading frame (ORF). Readthrough of the amber stop codon of the p33 ORF results in the production of a 92-kDa fusion protein. Both of these products are expressed directly from the viral genome and are suspected to be involved in viral RNA replication. We have investigated further the roles of these proteins in the amplification of viral RNAs by using a complementation system in which p33 and p92 are expressed from different viral RNAs. Our results indicate that (i) both of these proteins are necessary for viral RNA amplification; (ii) translation of these proteins can be uncoupled while maintaining amplification of viral RNAs; (iii) if compatibility requirements exist between p33 and p92, they are not exceptionally strict; and (iv) the C-terminal ∼6% of p33 is necessary for its functional activity. Interestingly, no complementation was observed when a p33-encoding replicon containing a deletion of a 3′-located segment, region 3.5, was tested. However, when 5′-capped transcripts of the same replicon were analyzed, complementation allowing for RNA amplification was observed. This ability to compensate functionally for the absence of region 3.5 by the addition of a 5′ cap suggests that this RNA segment may act as a translational enhancer for the expression of virally encoded products.

scholarly journals Ascorbic Acid Promotes Functional Restoration after Spinal Cord Injury Partly by Epigenetic Modulation

Cells ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 1310 ◽  
Author(s):  
Jin Young Hong ◽  
Ganchimeg Davaa ◽  
Hyunjin Yoo ◽  
Kwonho Hong ◽  
Jung Keun Hyun
Keyword(s):  
Spinal Cord ◽  
Dna Methylation ◽  
Spinal Cord Injury ◽  
Ascorbic Acid ◽  
Motor Cortex ◽  
Functional Restoration ◽  
Mrna Levels ◽  
Cord Injury ◽  
Epigenetic Modulation ◽  
The Brain

Axonal regeneration after spinal cord injury (SCI) is difficult to achieve, and no fundamental treatment can be applied in clinical settings. DNA methylation has been suggested to play a role in regeneration capacity and neuronal growth after SCI by controlling the expression of regeneration-associated genes (RAGs). The aim of this study was to examine changes in neuronal DNA methylation status after SCI and to determine whether modulation of DNA methylation with ascorbic acid can enhance neuronal regeneration or functional restoration after SCI. Changes in epigenetic marks (5-hydroxymethylcytosine (5hmC) and 5-methylcytosine (5mC)); the expression of Ten-eleven translocation (Tet) family genes; and the expression of genes related to inflammation, regeneration, and degeneration in the brain motor cortex were determined following SCI. The 5hmC level within the brain was increased after SCI, especially in the acute and subacute stages, and the mRNA levels of Tet gene family members (Tet1, Tet2, and Tet3) were also increased. Administration of ascorbic acid (100 mg/kg) to SCI rats enhanced 5hmC levels; increased the expression of the Tet1, Tet2, and Tet3 genes within the brain motor cortex; promoted axonal sprouting within the lesion cavity of the spinal cord; and enhanced recovery of locomotor function until 12 weeks. In conclusion, we found that epigenetic status in the brain motor cortex is changed after SCI and that epigenetic modulation using ascorbic acid may contribute to functional recovery after SCI.

scholarly journals High Numbers of Viral RNA Copies in the Central Nervous System of Mice during Persistent Infection with Theiler's Virus

2001 ◽  
Vol 75 (16) ◽  
pp. 7420-7428 ◽  
Author(s):  
Mark Trottier ◽  
Pat Kallio ◽  
Wei Wang ◽  
Howard L. Lipton
Keyword(s):  
Spinal Cord ◽  
Central Nervous System ◽  
Infectious Virus ◽  
Rna Replication ◽  
Cell Types ◽  
Viral Rna ◽  
Minus Strand ◽  
Viral Genomes ◽  
The Central Nervous System ◽  
Low Levels

ABSTRACT The low-neurovirulence Theiler's murine encephalomyelitis viruses (TMEV), such as BeAn virus, cause a persistent infection of the central nervous system (CNS) in susceptible mouse strains that results in inflammatory demyelination. The ability of TMEV to persist in the mouse CNS has traditionally been demonstrated by recovering infectious virus from the spinal cord. Results of infectivity assays led to the notion that TMEV persists at low levels. In the present study, we analyzed the copy number of TMEV genomes, plus- to minus-strand ratios, and full-length species in the spinal cords of infected mice and infected tissue culture cells by using Northern hybridization. Considering the low levels of infectious virus in the spinal cord, a surprisingly large number of viral genomes (mean of 3.0 × 109) was detected in persistently infected mice. In the transition from the acute (approximately postinfection [p.i.] day 7) to the persistent (beginning on p.i. day 28) phase of infection, viral RNA copy numbers steadily increased, indicating that TMEV persistence involves active viral RNA replication. Further, BeAn viral genomes were full-length in size; i.e., no subgenomic species were detected and the ratio of BeAn virus plus- to minus-strand RNA indicated that viral RNA replication is unperturbed in the mouse spinal cord. Analysis of cultured macrophages and oligodendrocytes suggests that either of these cell types can potentially synthesize high numbers of viral RNA copies if infected in the spinal cord and therefore account for the heavy viral load. A scheme is presented for the direct isolation of both cell types directly from infected spinal cords for further viral analyses.

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