RESUMO
A novel bunyavirus was recently found to cause severe febrile illness with high mortality in agricultural regions of China, Japan, and South Korea. This virus, named severe fever with thrombocytopenia syndrome virus (SFTSV), represents a new group within the Phlebovirus genus of the Bunyaviridae. Little is known about the viral entry requirements beyond showing dependence on dynamin and endosomal acidification. A haploid forward genetic screen was performed to identify host cell requirements for SFTSV entry. The screen identified dependence on glucosylceramide synthase (ugcg), the enzyme responsible for initiating de novo glycosphingolipid biosynthesis. Genetic and pharmacological approaches confirmed that UGCG expression and enzymatic activity were required for efficient SFTSV entry. Furthermore, inhibition of UGCG affected a post-internalization stage of SFTSV entry, leading to the accumulation of virus particles in enlarged cytoplasmic structures, suggesting impaired trafficking and/or fusion of viral and host membranes. These findings specify a role for glucosylceramide in SFTSV entry and provide a novel target for antiviral therapies.
Assuntos
Infecções por Bunyaviridae/metabolismo , Febre/virologia , Glicolipídeos/metabolismo , Trombocitopenia/virologia , Internalização do Vírus , Animais , Infecções por Bunyaviridae/virologia , China , Humanos , Japão , Orthobunyavirus/isolamento & purificação , Orthobunyavirus/metabolismo , Phlebovirus/isolamento & purificação , Phlebovirus/metabolismo , República da CoreiaRESUMO
The Bunyaviridae comprise a large family of RNA viruses with worldwide distribution and includes the pathogenic New World hantavirus, Andes virus (ANDV). Host factors needed for hantavirus entry remain largely enigmatic and therapeutics are unavailable. To identify cellular requirements for ANDV infection, we performed two parallel genetic screens. Analysis of a large library of insertionally mutagenized human haploid cells and a siRNA genomic screen converged on components (SREBP-2, SCAP, S1P and S2P) of the sterol regulatory pathway as critically important for infection by ANDV. The significance of this pathway was confirmed using functionally deficient cells, TALEN-mediated gene disruption, RNA interference and pharmacologic inhibition. Disruption of sterol regulatory complex function impaired ANDV internalization without affecting virus binding. Pharmacologic manipulation of cholesterol levels demonstrated that ANDV entry is sensitive to changes in cellular cholesterol and raises the possibility that clinically approved regulators of sterol synthesis may prove useful for combating ANDV infection.
Assuntos
Colesterol/metabolismo , Infecções por Hantavirus/metabolismo , Interações Hospedeiro-Parasita/fisiologia , Orthohantavírus/patogenicidade , Internalização do Vírus , Linhagem Celular , Citometria de Fluxo , Humanos , Microscopia Confocal , Mutagênese Sítio-Dirigida , Reação em Cadeia da Polimerase , Transdução de Sinais/fisiologia , Esteróis/metabolismo , Transdução Genética , Replicação Viral/fisiologiaRESUMO
Zinc is an essential trace element required in the diet of all species. While the effects of zinc have been studied in growing calves, little is known about the effect of zinc on the microbiota of the gestating cow or her neonatal calf. Understanding factors that shape the gut health of neonatal animals and evaluating the effect of dietary supplements in adult gestating animals is important in promoting animal health and informing feeding practices. The aims of this study were to determine the effect of dietary zinc on the microbiota and resistome of the gestating cow and calf. Gestating cows received standard (40 ppm) or high (205 ppm) dietary zinc levels from dry off to calving. Fecal samples were collected from cows upon enrollment and at calving and from neonatal calves. Fecal samples underwent 16S rRNA sequencing and a subset also underwent shotgun metagenomic sequencing. The effect of zinc supplementation on the diversity and composition of the cow and calf microbiome and resistome was assessed. Alpha and beta diversity and composition of the microbiota were significantly altered over time but not by treatment in the cows, with alpha diversity decreasing and 14 genera found at significantly higher relative abundances at calving compared to enrollment. Levels of 27 antimicrobial resistance genes significantly increased over time. Only a small number of taxa were differentially expressed at calving in treatment and control groups, including Faecalibacterium, Bacteroides, Turicibacter, and Bifidobacterium pseudolongum. No effect of the dam's treatment group was observed on the diversity or composition of the neonatal calf microbiota. The calf resistome, which was relatively rich and diverse compared to the cow, was also unaffected by the dam's treatment group. The impact of high levels of dietary zinc thus appeared to be minimal, with no observed changes in alpha or beta diversity, and few changes in the relative abundance of a small number of taxa and antimicrobial resistance genes.
Assuntos
Pigmentos Biológicos , Doenças dos Ovinos , Animais , Feminino , Ovinos , Pigmentos Biológicos/urinaRESUMO
PURPOSE OF REVIEW: This review will highlight some of the recent advances in genome engineering with applications for both clinical and basic science investigations of HIV-1. RECENT FINDINGS: Over the last year, the field of HIV cure research has seen major breakthroughs with the success of the first phase I clinical trial involving gene editing of CCR5 in patient-derived CD4(+) T cells. This first human use of gene-editing technology was accomplished using zinc finger nucleases (ZFNs). Zinc finger nucleases and the advent of additional tools for genome engineering, including transcription activator-like effector nucleases (TALENS) and the clustered regularly interspaced short palindromic repeat (CRISPR)/Cas9 system, have made gene editing remarkably simple and affordable. Here we will discuss the different gene-editing technologies, the use of gene editing in HIV research over the past year, and potential applications of gene editing for both in-vitro and in-vivo studies. SUMMARY: Genome-engineering technologies have rapidly progressed over the past few years such that these systems can be easily applied in any laboratory for a variety of purposes. For HIV-1, upcoming clinical trials will determine if gene editing can provide the long-awaited functional cure. In addition, manipulation of host genomes, whether in vivo or in vitro, can facilitate development of better animal models and culture methods for studying HIV-1 transmission, pathogenesis, and virus-host interactions.