title: Activation of toll-like receptors alters the microRNA expression profile of keratinocytes.
abstract: Keratinocytes recognize invading pathogens by various receptors, among them Toll-like receptors (TLRs), and provide the first line of defense in skin immunity. The role of microRNAs in this important defense mechanism has not been explored yet. Our aim was to identify microRNAs involved in the innate immune response of keratinocytes. MicroRNA expression profiling revealed that the TLR2 ligand zymosan, the TLR3 ligand poly(I:C) or the TLR5 ligand flagellin significantly altered the microRNA expression in keratinocytes. The regulation of microRNAs was concentration-dependent and it could be neutralized by siRNAs specific for TLR2, TLR3 and TLR5, respectively, confirming the specificity of the TLR response. Interestingly, one microRNA, miR-146a, was strongly induced by all studied TLR ligands, while other microRNAs were regulated in a TLR- or time point-specific manner. These findings suggest an important role for microRNAs in the innate immune response of keratinocytes and provide a basis for further investigations.
authors.affiliation: Unit of Dermatology and Venereology, Department of Medicine, Karolinska Institutet, Stockholm, Sweden.
authors.forename: Florian
authors.initials: F
authors.lastname: Meisgen
authors.forename: Ning
authors.initials: N
authors.lastname: Xu Landén
authors.forename: Charbel
authors.initials: C
authors.lastname: Bouez
authors.forename: Michela
authors.initials: M
authors.lastname: Zuccolo
authors.forename: Audrey
authors.initials: A
authors.lastname: Gueniche
authors.forename: Mona
authors.initials: M
authors.lastname: Ståhle
authors.forename: Enikö
authors.initials: E
authors.lastname: Sonkoly
authors.forename: Lionel
authors.initials: L
authors.lastname: Breton
authors.forename: Andor
authors.initials: A
authors.lastname: Pivarcsi
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism*; D008024:Ligands; D035683:MicroRNAs / Q000378:metabolism*; D051193:Toll-Like Receptors / Q000819:agonists / Q000378:metabolism*
chemical_list: D008024:Ligands; D035683:MicroRNAs; D051193:Toll-Like Receptors
keywords: Toll-like receptors; epidermis; host defense innate; immunity