Functional Variants in NFKBIE and RTKN2 Involved in Activation of the NF-kappa B Pathway Are Associated with Rheumatoid Arthritis in Japanese
PLOS GENETICS
Authors: Myouzen, Keiko; Kochi, Yuta; Okada, Yukinori; Terao, Chikashi; Suzuki, Akari; Ikari, Katsunori; Tsunoda, Tatsuhiko; Takahashi, Atsushi; Kubo, Michiaki; Taniguchi, Atsuo; Matsuda, Fumihiko; Ohmura, Koichiro; Momohara, Shigeki; Mimori, Tsuneyo; Yamanaka, Hisashi; Kamatani, Naoyuki; Yamada, Ryo; Nakamura, Yusuke; Yamamoto, Kazuhiko
Abstract
Rheumatoid arthritis is an autoimmune disease with a complex etiology, leading to inflammation of synovial tissue and joint destruction. Through a genome-wide association study (GWAS) and two replication studies in the Japanese population (7,907 cases and 35,362 controls), we identified two gene loci associated with rheumatoid arthritis susceptibility (NFKBIE at 6p21.1, rs2233434, odds ratio (OR) = 1.20, P = 1.3 x 10(-15); RTKN2 at 10q21.2, rs3125734, OR = 1.20, P = 4.6 x 10(-9)). In addition to two functional non-synonymous SNPs in NFKBIE, we identified candidate causal SNPs with regulatory potential in NFKBIE and RTKN2 gene regions by integrating in silico analysis using public genome databases and subsequent in vitro analysis. Both of these genes are known to regulate the NF-kappa B pathway, and the risk alleles of the genes were implicated in the enhancement of NF-kappa B activity in our analyses. These results suggest that the NF-kappa B pathway plays a role in pathogenesis and would be a rational target for treatment of rheumatoid arthritis.
Relationship between gene expression and lung function in Idiopathic Interstitial Pneumonias
BMC GENOMICS
Authors: Steele, Mark P.; Luna, Leah G.; Coldren, Christopher D.; Murphy, Elissa; Hennessy, Corinne E.; Heinz, David; Evans, Christopher M.; Groshong, Steve; Cool, Carlyne; Cosgrove, Gregory P.; Brown, Kevin K.; Fingerlin, Tasha E.; Schwarz, Marvin I.; Schwartz, David A.; Yang, Ivana V.
Abstract
Background: Idiopathic interstitial pneumonias (IIPs) are a group of heterogeneous, somewhat unpredictable diseases characterized by progressive scarring of the interstitium. Since lung function is a key determinant of survival, we reasoned that the transcriptional profile in IIP lung tissue would be associated with measures of lung function, and could enhance prognostic approaches to IIPs. Results: Using gene expression profiling of 167 lung tissue specimens with IIP diagnosis and 50 control lungs, we identified genes whose expression is associated with changes in lung function (% predicted FVC and % predicted DLCO) modeled as categorical (severe vs mild disease) or continuous variables while adjusting for smoking status and IIP subtype; false discovery rate (FDR) approach was used to correct for multiple comparisons. This analysis identified 58 transcripts that are associated with mild vs severe disease (categorical analysis), including those with established role in fibrosis (ADAMTS4, ADAMTS9, AGER, HIF-1 alpha, SERPINA3, SERPINE2, and SELE) as well as novel IIP candidate genes such as rhotekin 2 (RTKN2) and peptidase inhibitor 15 (PI15). Protein-protein interactome analysis of 553 genes whose expression is significantly associated with lung function when modeled as continuous variables demonstrates that more severe presentation of IIPs is characterized by an increase in cell cycle progression and apoptosis, increased hypoxia, and dampened innate immune response. Our findings were validated in an independent cohort of 131 IIPs and 40 controls at the mRNA level and for one gene (RTKN2) at the protein level by immunohistochemistry in a subset of samples. Conclusions: We identified commonalities and differences in gene expression among different subtypes of IIPs. Disease progression, as characterized by lower measures of FVC and DLCO, results in marked changes in expression of novel and established genes and pathways involved in IIPs. These genes and pathways represent strong candidates for biomarker studies and potential therapeutic targets for IIP severity.