Host-virus interaction: a new role for microRNAs

Abstract

MicroRNAs (miRNAs) are a new class of 18-23 nucleotide long non-coding RNAs that play critical roles in a wide spectrum of biological processes. Recent reports also throw light into the role of microRNAs as critical effectors in the intricate host-pathogen interaction networks. Evidence suggests that both virus and hosts encode microRNAs. The exclusive dependence of viruses on the host cellular machinery for their propagation and survival also make them highly susceptible to the vagaries of the cellular environment like small RNA mediated interference. It also gives the virus an opportunity to fight and/or modulate the host to suite its needs. Thus the range of interactions possible through miRNA-mRNA cross-talk at the host-pathogen interface is large. These interactions can be further fine-tuned in the host by changes in gene expression, mutations and polymorphisms. In the pathogen, the high rate of mutations adds to the complexity of the interaction network. Though evidence regarding microRNA mediated cross-talk in viral infections is just emerging, it offers an immense opportunity not only to understand the intricacies of hostpathogen interactions, and possible explanations to viral tropism, latency and oncogenesis, but also to develop novel biomarkers and therapeutics.

Stimulation of Inducible Nitric Oxide by Hepatitis B Virus Transactivator Protein HBx Requires MTA1 Coregulator

“…This is particularly novel because miR-661 was able to control the expression of iNOS in a manner that is dependent on MTA1 or could be rescued by MTA1 overexpression. Our observation that HBx inhibits miR-661 level is important because, in most cases, cellular miRNA acts as a defense mechanism against viruses by restricting viral accumulation or targeting viral nucleic acids/genes (32). For example, hepatitis C virus utilizes cellular miRNA to target the 5Ј-UTR of the viral genome, leading to RNA accumulation (43).…”

“…MicroRNA, a small RNA with an average length between 18 and 23 nucleotides, is involved in a gamut of cellular processes, including cell differentiation, apoptosis, neoplasia, develop-ment and pathophysiological events, such as host-virus interaction, viral oncogenesis, and tumorigenesis (31)(32)(33). For example, cellular miRNAs have been demonstrated to target foreign nucleic acids of the viruses (e.g.…”

“…For example, cellular miRNAs have been demonstrated to target foreign nucleic acids of the viruses (e.g. primate foamy virus, human immunodeficiency virus, and influenza virus) (32,34). MicroRNA also acts as a post-transcriptional modifier of the target gene regulation (35).…”

Viral epigenomes in human tumorigenesis

“…All of the herpesviruses analyzed until now express miRNAs and, in particular, EBV is known to encode 420 miRNAs (Cai et al, 2006;Grundhoff et al, 2006;Gurtsevitch, 2008;Cullen, 2009) that are differentially expressed in the different phases of the viral life cycle and between types of latency (Cai et al, 2006). EBVencoded miRNAs regulate both host and viral genes, hence an investigation of these relationships is very important for our understanding of the biological processes involved in viral latency, which could be exploited to design strategies for combating potential harm to the host (Pfeffer et al, 2004;Nair and Zavolan, 2006;Scaria et al, 2006;Gottwein and Cullen, 2008). In this regard, the interactions between BART miRNAs, such as miR-BART16, and LMP1, the most oncogenic known gene in EBV (Table 1), have been demonstrated (Grey et al, 2008;Cullen, 2009 …”

Deepening the Conception of Functional Information in the Description of Zoonotic Infectious Diseases

“…These interactions can be further fine-tuned in the host by changes in gene expression, mutations and polymorphisms. In the pathogen, the high rate of mutations adds to the complexity of the interaction network [60].…”