Involvement and Roles of Long Noncoding RNAs in the Molecular Mechanisms of Emerging and Reemerging Viral Infections

The studies on the mechanisms of viral–host interactions in infections have been focusing on protein-coding sequences of the genome. Although it is essential to consider the nonprotein-coding part that represents approximately 80% of the human genome. Thus advances in sequencing techniques have led to the discovery of thousands of RNAs with low or no capacity to encode proteins but are exhibiting crucial biological functions. Long noncoding RNAs (ncRNAs) (lncRNAs) are a heterogeneous class of these ncRNAs that are longer than 200 nt. Accumulating evidences have demonstrated the involvement of these molecules in development and physiological processes, especially through their regulation of gene expression. LncRNAs are encoded in mammalian cells as well as in microorganisms and viruses. Several studies have found differential expressions of lncRNAs in response to viral infection of emerging viruses, which suggest important roles. In fact, they are involved in promoting viral replication, evading host immunity and regulating the host response to the infection. In addition, lncRNAs do not induce immune response compared to viral proteins; thus viruses might employ them as an effective strategy to invade their hosts. In this chapter, we discuss particularly the emerging virus–host interaction associated lncRNAs through addressing their involvement in the mechanisms underlying emerging viral infections as well as in the pathways of immune system in response to these infections. We also discuss the promising role of these noncoding transcripts as biomarkers for diagnosing viral pathologies.