MicroRNAs: Small Molecules with Significant Functions, Particularly in the Context of Viral Hepatitis B and C Infection

Abstract

A MicroRNA (miRNA) is defined as a small molecule of non-coding RNA (ncRNA). Its molecular size is about 20 nucleotides (nt), and it acts on gene expression’s regulation at the post-transcription level through binding to the 3’untranslated regions (UTR), coding sequences, or 5’UTR of the target messenger RNAs (mRNAs), which leads to the suppression or degradation of the mRNA. In recent years, a huge evolution has identified the origin and function of miRNAs, focusing on their important effects in research and clinical applications. For example, microRNAs are key players in HCV infection and have important host cellular factors required for HCV replication and cell growth. Altered expression of miRNAs affects the pathogenicity associated with HCV infection through regulating different signaling pathways that control HCV/immunity interactions, proliferation, and cell death. On the other hand, circulating miRNAs can be used as novel biomarkers and diagnostic tools for HCV pathogenesis and early therapeutic response. Moreover, microRNAs (miRNA) have been involved in hepatitis B virus (HBV) gene expression and advanced antiviral discovery. They regulate HBV/HCV replication and pathogenesis with different pathways involving facilitation, inhibition, activation of the immune system (innate and adaptive), and epigenetic modifications. In this short review, we will discuss how microRNAs can be used as prognostic, diagnostic, and therapeutic tools, especially for chronic hepatitis viruses (HBV and HCV), as well as how they could be used as new biomarkers during infection and advanced treatment.

Hepatitis B Virus and microRNAs: A Bioinformatics Approach

“…Consequently, identifying the precise role of a specific miRNA is complex, representing one of the main challenges [37]. The abovementioned host (human) miRNAs are indeed also implicated in other diseases and functions not related to HBV (e.g., miR-122 in HCV) [40,187]. In this context, it makes even more sense to focus more on the study of viral miRNAs, which may show greater sensitivity and specificity.…”

“…The identification and characterization of viral/host miRNAs and their gene targets can aid in understanding the complex interactions between viruses and their host. Consequently, they might serve as diagnostic biomarkers based on their presence and levels in patient samples [185][186][187], offer insights into disease prognosis through their different expression during infection [188], and present opportunities as therapeutic targets for the development of antiviral drugs (i.e., anti-miR therapy) [189,190]. Furthermore, their use could extend to monitoring treatment response by evaluating the treatment efficacy [191].…”

IGF2BP1—An Oncofetal RNA-Binding Protein Fuels Tumor Virus Propagation

“…Another important class of molecules involved in regulating viral RNAs are microRNAs (miRNAs), small non-coding RNAs that direct the post-transcriptional repression of mRNA targets [ 7 ]. Cellular miRNAs can exert anti- or proviral effects and they are often dysregulated upon viral infections [ 8 , 9 ]. For example, miRNA-128 limits the replication and dissemination of the human immunodeficiency virus type 1 (HIV-1), whereas miRNA-34 promotes HIV-1 pathogenesis by inducing the accelerated decay of host proteins influencing the HIV-1 life cycle [ 10 , 11 ].…”