Divergent MicroRNA targetomes of closely related circulating strains of a polyomavirus

Hundreds of virus-encoded microRNAs (miRNAs) have been uncovered, but an in-depth functional understanding is lacking for most. A major challenge for the field is separating those miRNA targets that are biologically relevant from those that are not advantageous to the virus. Here, we show that miRNAs from related variants of the polyomavirus simian vacuolating virus 40 (SV40) have differing host target repertoires (targetomes) while their direct autoregulatory activity on virus-encoded early gene products is completely preserved. These results underscore the importance of miRNA-mediated viral gene autoregulation in some polyomavirus life cycles. More broadly, these findings imply that some host targets of virus-encoded miRNAs are likely to be of little selective advantage to the virus, and our approach provides a strategy for prioritizing relevant targets.

Production and biomedical applications of virus-like particles derived from polyomaviruses

Virus-like particles (VLPs), aggregates of capsid proteins devoid of viral genetic material, show great promise in the fields of vaccine development and gene therapy. These particles spontaneously self-assemble after heterologous expression of viral structural proteins. This review will focus on the use of virus-like particles derived from polyomavirus capsid proteins. Since their first recombinant production 27 years ago these particles have been investigated for a myriad of biomedical applications. These virus-like particles are safe, easy to produce, can be loaded with a broad range of diverse cargoes and can be tailored for specific delivery or epitope presentation. We will highlight the structural characteristics of polyomavirus-derived VLPs and give an overview of their applications in diagnostics, vaccine development and gene delivery.

The human virome: new tools and concepts

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New sequencing technologies increase our knowledge regarding the composition of the human virome.

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There are beneficial and detrimental viruses.

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The human virome can impact upon health at body surfaces (skin or gut) and within tissues.

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Some animal viruses are transmitted via the oral route by consumption of food.

The human virome is the viral component of the microbiome. Its composition, and interindividual and temporal variability are not precisely known. Its impact on human health has received less attention than that of the bacterial microbiome, but is likely to be equally important, both in homeostasis and disease. Here we review the recent advances in this field and the questions that arise in the context of our rapidly increasing knowledge regarding the composition and function of the human virome. With the ever-extending use of next-generation sequencing (NGS) on a variety of clinical samples, rapid progress on the composition of the human virome and its impact upon human health are to be expected in the coming years.

Prevalence of 10 human polyomaviruses in fecal samples from children with acute gastroenteritis: a case-control study

We conducted a case-control study to explore the prevalence of 10 human polyomaviruses in fecal specimens from hospitalized children with diarrhea and asymptomatic control subjects by using multiplex PCR detected by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The differences between cases and controls were not statistically significant.

Human polyomavirus reactivation: disease pathogenesis and treatment approaches

JC and BK polyomaviruses were discovered over 40 years ago and have become increasingly prevalent causes of morbidity and mortality in a variety of distinct, immunocompromised patient cohorts. The recent discoveries of eight new members of the Polyomaviridae family that are capable of infecting humans suggest that there are more to be discovered and raise the possibility that they may play a more significant role in human disease than previously understood. In spite of this, there remains a dearth of specific therapeutic options for human polyomavirus infections and an incomplete understanding of the relationship between the virus and the host immune system. This review summarises the human polyomaviruses with particular emphasis on pathogenesis in those directly implicated in disease aetiology and the therapeutic options available for treatment in the immunocompromised host.

A cornucopia of human polyomaviruses

During the past 6 years, focused virus hunting has led to the discovery of nine new human polyomaviruses, including Merkel cell polyomavirus, which has been linked to Merkel cell carcinoma, a lethal skin cell cancer. The discovery of so many new and highly divergent human polyomaviruses raises key questions regarding their evolution, tropism, latency, reactivation, immune evasion and contribution to disease. This Review describes the similarities and differences among the new human polyomaviruses and discusses how these viruses might interact with their human host.