Controlling systems of nucleic acid sensing-TLRs restrict homeostatic inflammation.

Nucleic acid sensing-TLRs recognize pathogen-derived nucleic acids (NAs) and induce anti-microbial immune responses. NA-sensing TLRs are reported to have a risk of mistakenly responding to self-derived NAs and causing a variety of autoimmune diseases. To warrant innate immune responses without detrimental inflammation, NA-sensing TLRs need to be tightly controlled in multiple aspects including expression and downstream signaling pathways. Along this line, TLR7 vs 9 balance has emerged as a new mechanism that controls activation of RNA-sensor TLR7. In this review, we discuss mechanisms controlling NA-sensing TLRs and autoimmune diseases as consequences of the dysregulated control mechanisms.