title: RNA recognition by human TLR8 can lead to autoimmune inflammation.
abstract: Studies on the role of the RNA receptor TLR8 in inflammation have been limited by its different function in human versus rodents. We have generated multiple lines of transgenic mice expressing different levels of human TLR8. The high copy number chimeras were unable to pass germline; developed severe inflammation targeting the pancreas, salivary glands, and joints; and the severity of the specific phenotypes closely correlated with the huTLR8 expression levels. Mice with relatively low expression levels survived and bred successfully but had increased susceptibility to collagen-induced arthritis, and the levels of huTLR8 correlated with proinflammatory cytokines in the joints of the animals. At the cellular level, huTLR8 signaling exerted a DC-intrinsic effect leading to up-regulation of co-stimulatory molecules and subsequent T cell activation. A pathogenic role for TLR8 in human diseases was suggested by its increased expression in patients with systemic arthritis and the correlation of TLR8 expression with the elevation of IL-1β levels and disease status. We found that the consequence of self-recognition via TLR8 results in a constellation of diseases, strikingly distinct from those related to TLR7 signaling, and points to specific inflammatory diseases that may benefit from inhibition of TLR8 in humans.
authors.affiliation: Dynavax Technologies Corporation, Berkeley, CA 94710.
authors.forename: Cristiana
authors.initials: C
authors.lastname: Guiducci
authors.forename: Mei
authors.initials: M
authors.lastname: Gong
authors.forename: Alma-Martina
authors.initials: AM
authors.lastname: Cepika
authors.forename: Zhaohui
authors.initials: Z
authors.lastname: Xu
authors.forename: Claudio
authors.initials: C
authors.lastname: Tripodo
authors.forename: Lynda
authors.initials: L
authors.lastname: Bennett
authors.forename: Chad
authors.initials: C
authors.lastname: Crain
authors.forename: Pierre
authors.initials: P
authors.lastname: Quartier
authors.forename: John J
authors.initials: JJ
authors.lastname: Cush
authors.forename: Virginia
authors.initials: V
authors.lastname: Pascual
authors.forename: Robert L
authors.initials: RL
authors.lastname: Coffman
authors.forename: Franck J
authors.initials: FJ
authors.lastname: Barrat
mesh_terms: D000818:Animals; D001169:Arthritis, Experimental / Q000378:metabolism / Q000503:physiopathology; D001171:Arthritis, Juvenile / Q000378:metabolism* / Q000503:physiopathology; D015551:Autoimmunity; D002648:Child; D003094:Collagen / Q000737:chemistry; D005260:Female; D020869:Gene Expression Profiling; D006801:Humans; D007249:Inflammation / Q000473:pathology*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012313:RNA / Q000737:chemistry*; D016032:Randomized Controlled Trials as Topic; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000276:immunology; D051199:Toll-Like Receptor 7 / Q000378:metabolism; D051200:Toll-Like Receptor 8 / Q000235:genetics / Q000378:metabolism*; D019076:Transgenes
chemical_list: C495348:TLR7 protein, human; C495349:TLR8 protein, human; D051199:Toll-Like Receptor 7; D051200:Toll-Like Receptor 8; D012313:RNA; D003094:Collagen