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The Journal of General Virology Nov 2023Human astroviruses (HAstVs) are small, non-enveloped icosahedral RNA viruses that are a significant cause of diarrhoea in young children. Despite their worldwide...
Human astroviruses (HAstVs) are small, non-enveloped icosahedral RNA viruses that are a significant cause of diarrhoea in young children. Despite their worldwide prevalence, HAstV pathogenesis studies and vaccine development remain challenging due to the lack of an animal model for HAstV infection. The recent development of a murine astrovirus (MuAstV) infection model in mice provides the opportunity to test proof-of-concept vaccines based on MuAstV antigens. To help establish a system in which an astrovirus capsid spike-based vaccine could be tested , we designed and produced a recombinant MuAstV capsid spike protein based on predicted secondary structure homology to HAstV spike proteins. The recombinant MuAstV spike can be expressed with high efficiency in and retains antigenicity to polyclonal antibodies elicited by MuAstV infection. We determined the crystal structure of the MuAstV spike to 1.75 Å and assessed its structural conservation with HAstV capsid spike. Despite low sequence identity between the MuAstV and HAstV spikes and differences in their overall shapes, they share related structural folds. Additionally, we found that vaccination with MuAstV spike induced anti-MuAstV-spike antibodies, highlighting that the recombinant spike is immunogenic. These studies lay a foundation for future MuAstV challenge studies to test whether MuAstV spike can be the basis of an effective vaccine.
Topics: Child; Humans; Animals; Mice; Child, Preschool; Capsid; Capsid Proteins; Astroviridae; Astroviridae Infections; Vaccines
PubMed: 37910165
DOI: 10.1099/jgv.0.001913 -
Viruses Jun 2022Porcine astrovirus (PAstV) has been identified as an important diarrheic pathogen with a broad global distribution. The PAstV is a potential pathogen to human beings and...
Porcine astrovirus (PAstV) has been identified as an important diarrheic pathogen with a broad global distribution. The PAstV is a potential pathogen to human beings and plays a role in public health. Until now, the divergence characteristics and pathogenesis of the PAstV are still not well known. In this study, the PAstV-4 strain PAstV/CH/2022/CM1 was isolated from the diarrheal feces of a piglet in Shanghai, which was identified to be a recombination of PAstV4/JPN (LC201612) and PAstV4/CHN (JX060808). A time tree based on the ORF2 protein of the astrovirus demonstrated that type 2-5 PAstV (PAstV-2 to 5) diverged from type 1 PAstV (PAstV-1) at a point from 1992 to 2000. To better understand the molecular basis of the virus, we sought to explore the host cell response to the PAstV/CH/2022/CM1 infection using proteomics. The results demonstrate that viral infection elicits global protein changes, and that the mitochondria seems to be a primary and an important target in viral infection. Importantly, there was crosstalk between autophagy and apoptosis, in which ATG7 might be the key mediator. In addition, the NOD-like receptor X1 (NLRX1) in the mitochondria was activated and participated in several important antiviral signaling pathways after the PAstV/CH/2022/CM1 infection, which was closely related to mitophagy. The NLRX1 may be a crucial protein for antagonizing a viral infection through autophagy, but this has yet to be validated. In conclusion, the data in this study provides more information for understanding the virus genomic characterization and the potential antiviral targets in a PAstV infection.
Topics: Animals; Antiviral Agents; Astroviridae Infections; China; Genomics; Humans; Mamastrovirus; Mitochondrial Proteins; Phylogeny; Proteomics; Swine; Swine Diseases
PubMed: 35891364
DOI: 10.3390/v14071383 -
Viruses Jun 2023Astroviruses are small nonenveloped single-stranded RNA viruses with a positive sense genome. They are known to cause gastrointestinal disease in a broad spectrum of...
Astroviruses are small nonenveloped single-stranded RNA viruses with a positive sense genome. They are known to cause gastrointestinal disease in a broad spectrum of species. Although astroviruses are distributed worldwide, a gap in knowledge of their biology and disease pathogenesis persists. Many positive-sense single-stranded RNA viruses show conserved and functionally important structures in their 5' and 3' untranslated regions (UTRs). However, not much is known about the role of the 5' and 3' UTRs in the viral replication of HAstV-1. We analyzed the UTRs of HAstV-1 for secondary RNA structures and mutated them, resulting in partial or total UTR deletion. We used a reverse genetic system to study the production of infectious viral particles and to quantify protein expression in the 5' and 3' UTR mutants, and we established an HAstV-1 replicon system containing two reporter cassettes in open reading frames 1a and 2, respectively. Our data show that 3' UTR deletions almost completely abolished viral protein expression and that 5' UTR deletions led to a reduction in infectious virus particles in infection experiments. This indicates that the presence of the UTRs is essential for the life cycle of HAstV-1 and opens avenues for further research.
Topics: Humans; 3' Untranslated Regions; Mamastrovirus; Viral Proteins; Virus Replication; 5' Untranslated Regions; RNA, Viral
PubMed: 37376701
DOI: 10.3390/v15061402 -
Journal of Virology Oct 2015Astroviruses are small, nonenveloped viruses with a single-stranded positive-sense RNA genome causing acute gastroenteritis in children and immunocompromised patients....
UNLABELLED
Astroviruses are small, nonenveloped viruses with a single-stranded positive-sense RNA genome causing acute gastroenteritis in children and immunocompromised patients. Since positive-sense RNA viruses have frequently been found to replicate in association with membranous structures, in this work we characterized the replication of the human astrovirus serotype 8 strain Yuc8 in Caco-2 cells, using density gradient centrifugation and free-flow zonal electrophoresis (FFZE) to fractionate cellular membranes. Structural and nonstructural viral proteins, positive- and negative-sense viral RNA, and infectious virus particles were found to be associated with a distinct population of membranes separated by FFZE. The cellular proteins associated with this membrane population in infected and mock-infected cells were identified by tandem mass spectrometry. The results indicated that membranes derived from multiple cell organelles were present in the population. Gene ontology and protein-protein interaction network analysis showed that groups of proteins with roles in fatty acid synthesis and ATP biosynthesis were highly enriched in the fractions of this population in infected cells. Based on this information, we investigated by RNA interference the role that some of the identified proteins might have in the replication cycle of the virus. Silencing of the expression of genes involved in cholesterol (DHCR7, CYP51A1) and fatty acid (FASN) synthesis, phosphatidylinositol (PI4KIIIβ) and inositol phosphate (ITPR3) metabolism, and RNA helicase activity (DDX23) significantly decreased the amounts of Yuc8 genomic and antigenomic RNA, synthesis of the structural protein VP90, and virus yield. These results strongly suggest that astrovirus RNA replication and particle assembly take place in association with modified membranes potentially derived from multiple cell organelles.
IMPORTANCE
Astroviruses are common etiological agents of acute gastroenteritis in children and immunocompromised patients. More recently, they have been associated with neurological diseases in mammals, including humans, and are also responsible for different pathologies in birds. In this work, we provide evidence that astrovirus RNA replication and virus assembly occur in contact with cell membranes potentially derived from multiple cell organelles and show that membrane-associated cellular proteins involved in lipid metabolism are required for efficient viral replication. Our findings provide information to enhance our knowledge of astrovirus biology and provide information that might be useful for the development of therapeutic interventions to prevent virus replication.
Topics: Adenosine Triphosphate; Astroviridae; Caco-2 Cells; Cell Fractionation; DEAD-box RNA Helicases; Fatty Acid Synthase, Type I; Fatty Acids; Gene Expression Regulation; Host-Pathogen Interactions; Humans; Inositol 1,4,5-Trisphosphate Receptors; Intracellular Membranes; Molecular Sequence Annotation; Oxidoreductases Acting on CH-CH Group Donors; Phosphotransferases (Alcohol Group Acceptor); Protein Interaction Mapping; RNA, Small Interfering; RNA, Viral; Signal Transduction; Sterol 14-Demethylase; Viral Proteins; Virus Replication
PubMed: 26246569
DOI: 10.1128/JVI.01225-15 -
Journal of Clinical Microbiology Oct 1985Three isolates of bovine astrovirus, one from the United Kingdom and two from the United States, possessed common antigens by immunofluorescence and strain-specific...
Three isolates of bovine astrovirus, one from the United Kingdom and two from the United States, possessed common antigens by immunofluorescence and strain-specific antigens by neutralization and were designated as two, and probably three, distinct serotypes. The isolate US2, despite being a different serotype, possessed the same restrictive cell tropism and cytopathology as previously reported for isolate US1, of the M cells of the dome epithelium of the Peyer's patches. Serotyping of 16 field isolates indicated the presence of more undefined serotypes.
Topics: Animals; Antigens, Viral; Cattle; Cattle Diseases; Fluorescent Antibody Technique; Intestinal Mucosa; Intestine, Small; Mamastrovirus; Neutralization Tests; Serotyping; United Kingdom; United States; Virus Diseases; Viruses, Unclassified
PubMed: 3935665
DOI: 10.1128/jcm.22.4.668-670.1985 -
Journal of Veterinary Diagnostic... Mar 2018Astroviruses are small, nonenveloped RNA viruses that have been linked to numerous diseases in a variety of species, including enteric disease in humans and cheetahs....
Astroviruses are small, nonenveloped RNA viruses that have been linked to numerous diseases in a variety of species, including enteric disease in humans and cheetahs. Species Mamastrovirus 2, previously known as feline astrovirus, has been isolated from the feces of domestic cats and cheetahs. A total of 122 cat fecal samples from Alachua County, FL Animal Services and the Veterinary Community Outreach Program at the University of Florida were analyzed, and 35 contained astroviral RNA that was amplified and identified using consensus RT-PCR and sequence analysis. Using phylogenetic analysis, 19 of the astroviral sequences were identified as Mamastrovirus 2, making it the most prevalent astrovirus in this population. Three samples were identified as an astrovirus similar to viruses previously identified in foxes in The Netherlands and a cat in California, and one was similar to a bat astrovirus. One astroviral sequence was identified as an Avastrovirus. Although a causative relationship between mamastroviruses and enteric disease in cats has yet to be established, it is clear that mamastroviruses are prevalent, and an understanding of prevalence of astroviral types may help direct future test development.
Topics: Acinonyx; Animals; Astroviridae Infections; Cat Diseases; Cats; Feces; Female; Florida; Male; Mamastrovirus; Prevalence
PubMed: 29202674
DOI: 10.1177/1040638717747322 -
Molecular Biology Reports Feb 2019Human astrovirus (HAstV) constitutes a major cause of acute gastroenteritis in children. The viral 5' and 3' untranslated regions (UTR) have been involved in the... (Review)
Review
Human astrovirus (HAstV) constitutes a major cause of acute gastroenteritis in children. The viral 5' and 3' untranslated regions (UTR) have been involved in the regulation of several molecular mechanisms. However, in astrovirues have been less characterized. Here, we analyzed the secondary structures of the 5' and 3' UTR of HAstV, as well as their putative target sites that might be recognized by cellular factors. To our knowledge, this is the first bioinformatic analysis that predicts the HAstV 5' UTR secondary structure. The analysis showed that both the UTR sequence and secondary structure are highly conserved in all HAstVs analyzed, suggesting their regulatory role of viral activities. Notably, the UTRs of HAstVs contain putative binding sites for the serine/arginine-rich factors SRSF2, SRSF5, SRSF6, SRSF3, and the multifunctional hnRNPE2 protein. More importantly, putative binding sites for PTB were localized in single-stranded RNA sequences, while hnRNPE2 sites were localized in double-stranded sequence of the HAstV 5' and 3' UTR structures. These analyses suggest that the combination of SRSF proteins, hnRNPE2 and PTB described here could be involved in the maintenance of the secondary structure of the HAstVs, possibly allowing the recruitment of the replication complex that selects and recruits viral RNA replication templates.
Topics: Base Sequence; Binding Sites; Computer Simulation; Mamastrovirus; Nucleic Acid Conformation; Proteins; Untranslated Regions
PubMed: 30448895
DOI: 10.1007/s11033-018-4498-8 -
Viruses Jun 2023Astroviruses (AstVs) have been detected in a wide range of animal species, including mammals and birds. Recently, a novel AstV associated with neurological symptoms has...
Astroviruses (AstVs) have been detected in a wide range of animal species, including mammals and birds. Recently, a novel AstV associated with neurological symptoms has been detected in the brains of some mammals. Raccoon dog AstV has been reported recently in China. However, there have been no reports in South Korea. Therefore, the present study aimed to detect and genetically characterize AstVs in the intestine and brain tissues of 133 wild raccoon dogs collected in Korea between 2017 and 2019. Of the seven raccoon dogs, AstVs were detected in six intestinal tissues and four brain tissues. Analysis of the capsid protein amino acid sequences of raccoon dog AstVs detected in Korea revealed a high similarity to canine AstVs, suggesting possible interspecies transmission between raccoon dogs and dogs. Phylogenetic and capsid protein amino acid sequence analysis of raccoon dog AstVs detected in the brain the 17-148B strain belonging to the HMO clade and exhibiting conserved sequences found in neurotropic AstVs (NT-AstVs), indicating their potential as NT-AstVs. However, the pathogenicity and transmission routes of the raccoon dog AstV detected in Korea have not yet been elucidated, so further research and continued surveillance for AstV in wild raccoon dogs are needed.
Topics: Animals; Dogs; Astroviridae Infections; Phylogeny; Raccoon Dogs; Capsid Proteins; Astroviridae
PubMed: 37515175
DOI: 10.3390/v15071488 -
Poultry Science Nov 2023Goose astroviruses (GoAstVs) are causative agents that account for fatal infection of goslings characterized by visceral urate deposition, resulting in severe economic...
Goose astroviruses (GoAstVs) are causative agents that account for fatal infection of goslings characterized by visceral urate deposition, resulting in severe economic losses in major goose-producing regions in China since 2017. In this study, we sought to unravel the intrinsic properties associated with adaptation and evolution in the host environment of GoAstVs. Consistent results from phylogenetic analysis and correspondence analysis performed on the codon usage patterns (CUPs) reveal 2 clusters of GoAstVs, namely, GoAstV-1 and GoAstV-2. However, multiple similar compositional characteristics were found, despite the high divergence between GoAstV-1 and GoAstV-2. Studies on the base composition of GoAstVs reveal an A/U bias, indicating a compositional constraint, while natural selection prevailed in determining the CUPs in the virus genome based on our neutrality plot analysis, reflecting high adaptive pressure to fit the host environment. Codon adaptation index (CAI) analysis revealed a higher degree of fitness to the CUPs of the corresponding host for GoAstVs than avian influenza virus and betacoronaviruses, which may be a favorable factor contributing to the high pathogenicity and wide distribution of GoAstVs in goslings. In addition, GoAstVs were less adapted to ducks and chickens, with significantly lower CAI values than to geese, which may be a reason for the different prevalence of GoAstVs among these species. Extensive investigations on dinucleotide distribution revealed a significant suppression of the CpG and UpA motifs in the virus genome, which may facilitate adaptation to the host's innate immune system by evading surveillance. In addition, our study reported the trends of increasing fitness to the host's microenvironment for GoAstVs through increasing adaptation to host CUPs and ongoing reduction of CpG motifs in the virus genome. The present analysis deepens our understanding of the basic biology, pathogenesis, adaptation and evolutionary pattern of GoAstVs, and contributes to the development of novel antiviral strategies.
Topics: Animals; Geese; Base Composition; Phylogeny; Chickens; Codon; Avastrovirus
PubMed: 37713803
DOI: 10.1016/j.psj.2023.103029 -
Virology Sep 2021Despite the ongoing interest in virus discovery, little is known about the factors that shape communities of viruses within individual hosts. Here, we address how virus...
Despite the ongoing interest in virus discovery, little is known about the factors that shape communities of viruses within individual hosts. Here, we address how virus communities might be impacted by the age of the hosts they infect, using total RNA sequencing to reveal the RNA viromes of different age groups of Ruddy Turnstones (Arenaria interpres). From oropharyngeal and cloacal swabs we identified 14 viruses likely infecting birds, 11 of which were novel, including members of the Reoviridae, Astroviridae, and Picornaviridae. Strikingly, 12 viruses identified were from juvenile birds sampled in the first year of their life, compared to only two viruses in adult birds. Both viral abundance and alpha diversity were marginally higher in juvenile than adult birds. As well as informing studies of virus ecology, that host age might be associated with viral composition is an important consideration for the future surveillance of novel and emerging viruses.
Topics: Aging; Animals; Astroviridae; Charadriiformes; Cloaca; Double Stranded RNA Viruses; Genome, Viral; Oropharynx; Phylogeny; Picornaviridae; RNA Viruses; Reoviridae; Transcriptome; Virome
PubMed: 34182259
DOI: 10.1016/j.virol.2021.06.007