MicroRNAs in infectious diseases: potential diagnostic biomarkers and therapeutic targets

Abstract

MicroRNAs (miRNAs) are conserved, short, non-coding RNAs that play a crucial role in the post-transcriptional regulation of gene expression. They have been implicated in the pathogenesis of cancer and neurological, cardiovascular, and autoimmune diseases. Several recent studies have suggested that miRNAs are key players in regulating the differentiation, maturation, and activation of immune cells, thereby influencing the host immune response to infection. The resultant upregulation or downregulation of miRNAs from infection influences the protein expression of genes responsible for the immune response and can determine the risk of disease progression. Recently, miRNAs have been explored as diagnostic biomarkers and therapeutic targets in various infectious diseases. This review summarizes our current understanding of the role of miRNAs during viral, fungal, bacterial, and parasitic infections from a clinical perspective, including critical functional mechanisms and implications for their potential use as biomarkers and therapeutic targets.

Keywords: bacterial infection; biomarker; fungal infection; microRNA; parasite infection; viral infection.

Fig 1

Functions of host-encoded miRNA during HCV infections. Illustrated here are examples of functional pathways of host-encoded miRNAs. Examples were chosen if they met the following criteria: (i) miRNA expression was compared to control populations or status without the infection; (ii) the target genes of the miRNA were identified in the study; (iii) the functional mechanisms reported had sufficient data; and (iv) the experiments were in human cell lines. In the left, miR-21 and miR-130a are upregulated and miR-182 is downregulated during HCV infection in a hepatocyte. In the right, miR-181a is downregulated during HCV infection in a CD4⁺ T cell. Abbreviations: CLDN1, claudin-1; DUSP6, dual specific phosphatase 6; IFITM1, interferon-induced transmembrane 1; IFN, interferon; IRAK1, interleukin-1 receptor-associated kinase; MyD88, myeloid differentiation factor 88; TCR, T-cell receptor.

Fig 2

Regulation pathway and functions of miR-146a and its related pathways during Aspergillus fumigatus infection in a macrophage cell line. Abbreviations: IL-6, interleukin 6; IRAK1, interleukin-1 receptor-associated kinase; NF-κB, nuclear factor-kappa B; p38 MARK, p38 mitogen-activated protein kinase; TLR, toll-like receptor; TNF-α, tumor necrosis factor alpha; TRAF6, TNF receptor-associated factor 6.