We performed a genome-wide association study in non-Hispanic white subjects with fibrotic idiopathic interstitial pneumonias (N=1616) and controls (N=4683); replication was assessed in 876 cases and 1890 controls. We confirmed association with TERT and MUC5B on chromosomes 5p15 and 11p15, respectively, the chromosome 3q26 region near TERC, and identified 7 novel loci (PMeta = 2.4×10−8 to PMeta = 1.1×10−19). The novel loci include FAM13A (4q22), DSP (6p24), OBFC1 (10q24), ATP11A (13q34), DPP9 (19p13), and chromosomal regions 7q22 and 15q14-15. Our results demonstrate that genes involved in host defense, cell-cell adhesion, and DNA repair contribute to the risk of fibrotic IIP.
Summary Background Idiopathic pulmonary fibrosis (IPF) is a devastating disease that probably involves several genetic loci. Several rare genetic variants and one common single nucleotide polymorphism (SNP) of MUC5B have been associated with the disease. Our aim was to identify additional common variants associated with susceptibility and ultimately mortality in IPF. Methods First, we did a three-stage genome-wide association study (GWAS): stage one was a discovery GWAS; and stages two and three were independent case-control studies. DNA samples from European-American patients with IPF meeting standard criteria were obtained from several US centres for each stage. Data for European-American control individuals for stage one were gathered from the database of genotypes and phenotypes; additional control individuals were recruited at the University of Pittsburgh to increase the number. For controls in stages two and three, we gathered data for additional sex-matched European-American control individuals who had been recruited in another study. DNA samples from patients and from control individuals were genotyped to identify SNPs associated with IPF. SNPs identified in stage one were carried forward to stage two, and those that achieved genome-wide significance (p<5 × 10−8) in a meta-analysis were carried forward to stage three. Three case series with follow-up data were selected from stages one and two of the GWAS using samples with follow-up data. Mortality analyses were done in these case series to assess the SNPs associated with IPF that had achieved genome-wide significance in the meta-analysis of stages one and two. Finally, we obtained gene-expression profiling data for lungs of patients with IPF from the Lung Genomics Research Consortium and analysed correlation with SNP genotypes. Findings In stage one of the GWAS (542 patients with IPF, 542 control individuals matched one-by-one to cases by genetic ancestry estimates), we identified 20 loci. Six SNPs reached genome-wide significance in stage two (544 patients, 687 control individuals): three TOLLIP SNPs (rs111521887, rs5743894, rs5743890) and one MUC5B SNP (rs35705950) at 11p15.5; one MDGA2 SNP (rs7144383) at 14q21.3; and one SPPL2C SNP (rs17690703) at 17q21.31. Stage three (324 patients, 702 control individuals) confirmed the associations for all these SNPs, except for rs7144383. Linkage disequilibrium between the MUC5B SNP (rs35705950) and TOLLIP SNPs (rs111521887 [r2=0.07], rs5743894 [r2=0.16], and rs5743890 [r2=0.01]) was low. 683 patients from the GWAS were included in the mortality analysis. Individuals who developed IPF despite having the protective TOLLIP minor allele of rs5743890 carried an increased mortality risk (meta-analysis with fixed-effect model: hazard ratio 1.72 [95% CI 1.24–2.38]; p=0.0012). TOLLIP expression was decreased by 20% in individuals carrying the minor allele of rs5743890 (p=0.097), 40% in those with the minor allele of rs111521887 (p=3.0 × 10−4), and 50% in those with the minor allele of rs5743894 (p=2.93 × 10−5) compa...
Deletion of uridylates from the 3'-most editing site of synthetic ATPase 6 pre-mRNA can be visualized directly by coincubation of a radiolabeled substrate RNA and a synthetic gRNA in 20S fractions of T.brucie mitochondrial lysates. Substrate RNA cleavage is gRNA directed and occurs 3' to the uridylates to be deleted. U residues appear to be sequentially removed from the 3' end of the 5' cleavage product prior to religation of the two pre-mRNA halves. gRNA/mRNA chimeric molecules are also produced. Time course experiments indicate that chimeras appear after cleavage intermediates and edited product. Furthermore, a mutant gRNA promotes formation of edited product but not detectable chimeras. Our results suggest a model for kinetoplastid RNA editing in which chimeric molecules are nonproductive end products of editing and not intermediates that serve as a repository for deleted U's.
Pirfenidone is an orally active small molecule that has recently been evaluated in large clinical trials for the treatment of idiopathic pulmonary fibrosis, a fatal disease in which the uncontrolled deposition of extracellular matrix leads to progressive loss of lung function. This review describes the activity of pirfenidone in several well-characterised animal models of fibrosis in the lung, liver, heart and kidney. In these studies, treatment-related reductions in fibrosis are associated with modulation of cytokines and growth factors, with the most commonly reported effect being reduction of transforming growth factor-b. The consistent antifibrotic activity of pirfenidone in a broad array of animal models provides a strong preclinical rationale for the clinical characterisation of pirfenidone in pulmonary fibrosis and, potentially, other conditions with a significant fibrotic component. KEYWORDS: Animal model, antifibrotic, fibrosis, idiopathic pulmonary fibrosis, pirfenidone F ibrosis, the dysregulated deposition of extracellular matrix (ECM) with progressive destruction of normal tissue, is a primary or contributing factor in chronic disease states in several organs. Pulmonary fibrosis is associated with numerous diffuse parenchymal lung diseases, of which the most common are idiopathic pulmonary fibrosis (IPF) and sarcoidosis [1]. Cardiac fibrosis is associated with chronic heart failure, atrial fibrillation, and cardiac remodelling following acute myocardial infarction [2,3]. Renal fibrosis is associated with multiple forms of chronic kidney disease and correlates with impairment of kidney function [4,5]. Hepatic fibrosis is associated with chronic hepatitis B and C viral infections and nonalcoholic steatohepatitis [6]. Each of these conditions represents a significant unmet medical need, warranting significant research and clinical study into treatment for fibrotic disease.Pirfenidone (Esbriet1, Pirespa1) is an orally active small molecule comprising a modified phenyl pyridone ( fig. 1). The compound exhibits well documented antifibrotic and anti-inflammatory activities in a variety of animal and cellbased models, although its molecular target has not been elucidated. Pirfenidone was initially identified as having anti-inflammatory activity in animal models and evaluated for use as an antiinflammatory drug [7,8]. However, the unexpected identification of antifibrotic effects in animals treated with pirfenidone redefined the interest in the compound [9]. Subsequently, pirfenidone has been shown to attenuate fibrosis in numerous animal models, including fibrosis of the lung, liver, heart and kidney.The most extensive clinical studies of pirfenidone are for treatment of IPF, a chronic interstitial lung disease characterised by the unregulated deposition of ECM leading to the unremitting destruction of normal lung. Patients diagnosed with IPF typically experience progressive pulmonary insufficiency, and most die of respiratory failure. The estimated median survival upon diagnosis is approximately ...
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