microRNAs in mycobacterial disease: friend or foe?

Abstract

As the role of microRNA in all aspects of biology continues to be unraveled, the interplay between microRNAs and human disease is becoming clearer. It should come of no surprise that microRNAs play a major part in the outcome of infectious diseases, since early work has implicated microRNAs as regulators of the immune response. Here, we provide a review on how microRNAs influence the course of mycobacterial infections, which cause two of humanity’s most ancient infectious diseases: tuberculosis and leprosy. Evidence derived from profiling and functional experiments suggests that regulation of specific microRNAs during infection can either enhance the immune response or facilitate pathogen immune evasion. Now, it remains to be seen if the manipulation of host cell microRNA profiles can be an opportunity for therapeutic intervention for these difficult-to-treat diseases.

The role of host miRNAs on Mycobacterium tuberculosis

“…The use of immune inhibitors, for example, using anti-TNF-α in rheumatoid arthritis patients or people with Acquired Immune Deficiency Syndrome (HIV) may lead latent bacteria to reactivate [7]. Currently, the attenuated strain of Mycobacterium bovis (M. bovis), Calmette-Guérin (BCG) is used as a vaccine against TB, which is extremely ineffective [8]. Nowadays, the prevalence of this illness has declined through serious human efforts in research and medical care, although the occurrence of multi-drug-resistant (MDR) and extensive drug resistance (XDR) strain is increasing, and reports on the emergence of totally drug-resistant strains (TDR) have been documented [9].…”

“…While macrophages are target cells for Mycobacterium infection but are not affected by miRNAs, during infection. The critical point of the inherent and acquired immune responses is dendritic cells that can activate and polarize the topical T cell responses, regulated by miRNAs [8]. miRNAs play an essential role in regulating the primary function of macrophages, dendritic cells, and Natural Killer Cells (NKCs) [46,47].…”

The Identification of Circulating MiRNA in Bovine Serum and Their Potential as Novel Biomarkers of Early Mycobacterium avium subsp paratuberculosis Infection

“…These short (~22 nt) non-coding RNAs regulate mRNA expression and are predicted to target at least one-third of known mammalian genes [ 12 , 13 ]. Some of the key miRNAs that are known to regulate immune responses to intracellular pathogens have been reported to be upregulated in several cell types in response to mycobacterial infections [ 14 , 15 ]. Thus, specific miRNA expression signatures in tissue samples appear to reflect the underlying host-defence processes in different tissues/cells, and it is possible that different stages of infection have distinct miRNA signatures.…”

Comprehensive identification and profiling of Nile tilapia (Oreochromis niloticus) microRNAs response to Streptococcus agalactiae infection through high-throughput sequencing

“…It should come of no surprise that microRNAs play a major part in the outcome of infectious diseases, since early work has implicated miRNAs as regulators of the immune response [7]. Evidence derived from profiling and functional experiments suggests that regulation of specific miRNAs during infection can either enhance the immune response or facilitate pathogen immune evasion [8]. Consequently, investigations on miRNAs of immune relevance are indispensable for understanding the host-pathogen interactions, and it remain to be seen an opportunity for therapeutic intervention for difficult-to-treat diseases [9,10].…”