Characterizing the genetic basis of innate immune response in TLR4-activated human monocytes
NATURE COMMUNICATIONS
Authors: Kim, Sarah; Becker, Jessica; Bechheim, Matthias; Kaiser, Vera; Noursadeghi, Mahdad; Fricker, Nadine; Beier, Esther; Klaschik, Sven; Boor, Peter; Hess, Timo; Hofmann, Andrea; Holdenrieder, Stefan; Wendland, Jens R.; Froehlich, Holger; Hartmann, Gunther; Noethen, Markus M.; Mueller-Myhsok, Bertram; Puetz, Benno; Hornung, Veit; Schumacher, Johannes
Abstract
Toll-like receptors (TLRs) play a key role in innate immunity. Apart from their function in host defense, dysregulation in TLR signalling can confer risk to autoimmune diseases, septic shock or cancer. Here we report genetic variants and transcripts that are active only during TLR signalling and contribute to interindividual differences in immune response. Comparing unstimulated versus TLR4-stimulated monocytes reveals 1,471 expression quantitative trait loci (eQTLs) that are unique to TLR4 stimulation. Among these we find functional SNPs for the expression of NEU4, CCL14, CBX3 and IRF5 on TLR4 activation. Furthermore, we show that SNPs conferring risk to primary biliary cirrhosis (PBC), inflammatory bowel disease (IBD) and celiac disease are immune response eQTLs for PDGFB and IL18R1. Thus, PDGFB and IL18R1 represent plausible candidates for studying the pathophysiology of these disorders in the context of TLR4 activation. In summary, this study presents novel insights into the genetic basis of the innate immune response and exemplifies the value of eQTL studies in the context of exogenous cell stimulation.
Evaluation of candidate genes in a genome-wide association study of childhood asthma in Mexicans
JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY
Authors: Wu, Hao; Romieu, Isabelle; Shi, Min; Hancock, Dana B.; Li, Huiling; Sienra-Monge, Juan-Jose; Chiu, Grace Y.; Xu, Hong; Estela del Rio-Navarro, Blanca; London, Stephanie J.
Abstract
Background: More than 200 asthma candidate genes have been examined in human association studies or identified with knockout mouse approaches. However, many have not been systematically replicated in human populations, especially those containing a large number of tagging single nucleotide polymorphisms (SNPs). Objective: We comprehensively evaluated the association of previously implicated asthma candidate genes with childhood asthma in a Mexico City population. Methods: From the literature, we identified candidate genes with at least 1 positive report of association with asthma phenotypes in human subjects or implicated in asthma pathogenesis using knockout mouse experiments. We performed a genome-wide association study in 492 asthmatic children aged 5 to 17 years and both parents using the Illumina HumanHap 5500 BeadChip. Separate candidate gene analyses were performed for 2933 autosomal SNPs in the 237 selected genes by using the log-linear method with a log-additive risk model. Results: Sixty-one of the 237 genes had at least 1 SNP with a P value of less than .05 for association with asthma. The 9 most significant results were observed for rs2241715 in the gene encoding TGF-beta 1 (TCFB1; P = 3.3 x 10(-5)), rs13431828 and rs1041973 in the gene encoding IL-1 receptor-like 1 (IL1RL1; P = 2 x 10(-4) and 3.5 x 10(-4)), 5 SNPs in the gene encoding dipeptidyl-peptidase 10 (DPP10; P = 1.6 x 10(-4) to 4.5 x 10(-4)), and rs17599222 in the gene encoding cytoplasmic FMR1 interacting protein 2 (CYFIP2; P = 4.1 x 10(-4)). False discovery rates were less than 0.1 for all 9 SNPs. Multimarker analysis identified TGFB1, IL1RL1, the gene encoding IL-18 receptor 1 (IL18R1), and DPP10 as the genes most significantly associated with asthma. Conclusions: This comprehensive analysis of literature-based candidate genes suggests that SNPs in several candidate genes, including TGFBI, IL1RL1, IL18R1, and DPP10, might contribute to childhood asthma susceptibility in a Mexican population. (J Allergy Clin Immunol 2010;125:321-7.)