Interplay between microRNAs, Toll-like receptors, and HIV-1: potential implications in HIV-1 replication and chronic immune activation.

MicroRNAs (miRNAs) are important cellular, small non-coding RNAs that regulate host gene expression and have well-characterized roles in inflammation and infectious diseases. It has become apparent as well that cellular miRNAs can play crucial roles in controlling HIV-1 infection and replication. Whether HIV-1 encodes and is able to express viral miRNAs in infected cells remains controversial. HIV-1 can manipulate the biogenesis of miRNAs as well as the expression profiles of cellular miRNAs. Toll-Like receptors (TLRs) are important pathogen recognition receptors that sense invading pathogens orchestrating innate and adaptive immune responses. Innate immune recognition of HIV-1 infection leads to activation of TLR7/8. Recent evidence has shown that certain miRNAs can also be recognized by TLR7/8 leading to immune activation. However, the potential TLR7/8-mediated recognition of HIV-1 encoded miRNAs and/or cellular miRNAs modulated in HIV-1 infected cells has not been experimentally explored. In this review, we summarize the current literature on HIV-1 infection and miRNAs. Furthermore, we underscore the need for future research on potential miRNA-induced activation of TLR7/8, which might contribute to the chronic immune activation observed in HIV-1 infected patients.