Eighty-eight variants highlight the role of T cell regulation and airway remodeling in asthma pathogenesis
NATURE COMMUNICATIONS
Authors: Olafsdottir, Thorunn A.; Theodors, Fannar; Bjarnadottir, Kristbjorg; Bjornsdottir, Unnur Steina; Agustsdottir, Arna B.; Stefansson, Olafur A.; Ivarsdottir, Erna, V; Sigurdsson, Jon K.; Benonisdottir, Stefania; Eyjolfsson, Gudmundur, I; Gislason, David; Gislason, Thorarinn; Gudmundsdottir, Steinunn; Gylfason, Arnaldur; Halldorsson, Bjarni, V; Halldorsson, Gisli H.; Juliusdottir, Thorhildur; Kristinsdottir, Anna M.; Ludviksdottir, Dora; Ludviksson, Bjorn R.; Masson, Gisli; Norland, Kristjan; Onundarson, Pall T.; Olafsson, Isleifur; Sigurdardottir, Olof; Stefansdottir, Lilja; Sveinbjornsson, Gardar; Tragante, Vinicius; Gudbjartsson, Daniel F.; Thorleifsson, Gudmar; Sulem, Patrick; Thorsteinsdottir, Unnur; Norddahl, Gudmundur L.; Jonsdottir, Ingileif; Stefansson, Kari
Abstract
Asthma is one of the most common chronic diseases affecting both children and adults. We report a genome-wide association meta-analysis of 69,189 cases and 702,199 controls from Iceland and UK biobank. We find 88 asthma risk variants at 56 loci, 19 previously unreported, and evaluate their effect on other asthma and allergic phenotypes. Of special interest are two low frequency variants associated with protection against asthma; a missense variant in TNFRSF8 and 3' UTR variant in TGFBR1. Functional studies show that the TNFRSF8 variant reduces TNFRSF8 expression both on cell surface and in soluble form, acting as loss of function. eQTL analysis suggests that the TGFBR1 variant acts through gain of function and together with an intronic variant in a downstream gene, SMAD3, points to defective TGF beta R1 signaling as one of the biological perturbations increasing asthma risk. Our results increase the number of asthma variants and implicate genes with known role in T cell regulation, inflammation and airway remodeling in asthma pathogenesis.
Withaferin a associated Differential regulation of inflammatory cytokines
FRONTIERS IN IMMUNOLOGY
Authors: Dubey, Seema; Yoon, Hyunho; Cohen, Mark Steven; Nagarkatti, Prakash; Nagarkatti, Mitzi; Karan, Dev
Abstract
A role of inflammation-associated cytokines/chemokines has been implicated in a wide variety of human diseases. Here, we investigated the regulation of inflammatory cytokines released by monocyte-derived THP-1 cells following treatment with the dietary agent withaferin A (WFA). Membrane-based cytokine array profiling of the culture supernatant from adenosine triphosphate-stimulated WFA-treated THP-1 cells showed differential regulation of multiple cytokines/chemokines. A selected group of cytokines/chemokines [interleukin-1 beta (IL-1 beta), CCL2/MCP-1, granulocyte-macrophage colony stimulating factor, PDGF-AA, PTX3, cystatin-3, relaxin-2, TNFRSF8/CD30, and ACRP30] was validated at the transcription level using qPCR. In silico analysis for transcriptional binding factors revealed the presence of nuclear factor-kappa B (NF-kappa B) in a group of down-regulated cytokine gene promoters. WFA treatment of THP-1 cells blocks the nuclear translocation of NF-kB and corresponds with the reduced levels of cytokine secretion. To further understand the differential expression of cytokines/chemokines, we showed that WFA alters the nigericin-induced co-localization of NLRP3 and ASC proteins, thereby inhibiting caspase-1 activation, which is responsible for the cleavage and maturation of pro-inflammatory cytokines IL-1 beta and IL-18. These data suggest that dietary agent WFA concurrently targets NF-kappa B and the inflammasome complex, leading to inhibition of IL-1 beta and IL-18, respectively, in addition to differential expression of multiple cytokines/chemokines. Taken together, these results provide a rationale for using WFA to further explore the anti-inflammatory mechanism of cytokines/chemokines associated with inflammatory diseases.