Regulation of TLR signaling pathways by microRNAs: implications in inflammatory diseases

The control of the immune response during the development of some diseases is crucial for the maintenance or restoration of homeostasis. Several mechanisms can initiate inflammation, one of which is the activation of toll-like receptors (TLRs), necessary to initiate the immune response to eliminate an infection. However, inappropriate activation can compromise immunological homeostasis, leading to pathologies such as autoimmune diseases, chronic inflammation, and even cancer. Regulatory mechanisms that intervene in the initiation or modulation of inflammation include microRNAs (miRNAs), which have emerged as key post-transcriptional regulators of proteins involved in distinct cellular processes, such as regulation of the immune response. The focus of this review is on the diverse roles of miRNAs in the regulation of TLR-signaling pathways by targeting multiple molecules, including TLRs, the signaling proteins and cytokines induced by TLRs. It will also address the relationships of these molecules with some diseases that involve inflammation such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), cancer, as well as bacterial or viral infections.