Idiopathic Pulmonary Fibrosis Is Associated with Common Genetic Variants and Limited Rare Variants.

Rationale: Idiopathic pulmonary fibrosis (IPF) is a rare, irreversible, and progressive disease of the lungs. Common genetic variants, in addition to nongenetic factors, have been consistently associated with IPF. Rare variants identified by candidate gene, family-based, and exome studies have also been reported to associate with IPF. However, the extent to which rare variants, genome-wide, may contribute to the risk of IPF remains unknown. Objectives: We used whole-genome sequencing to investigate the role of rare variants, genome-wide, on IPF risk. Methods: As part of the Trans-Omics for Precision Medicine Program, we sequenced 2,180 cases of IPF. Association testing focused on the aggregated effect of rare variants (minor allele frequency ⩽0.01) within genes or regions. We also identified individual rare variants that are influential within genes and estimated the heritability of IPF on the basis of rare and common variants. Measurements and Main Results: Rare variants in both TERT and RTEL1 were significantly associated with IPF. A single rare variant in each of the TERT and RTEL1 genes was found to consistently influence the aggregated test statistics. There was no significant evidence of association with other previously reported rare variants. The SNP heritability of IPF was estimated to be 32% (SE = 3%). Conclusions: Rare variants within the TERT and RTEL1 genes and well-established common variants have the largest contribution to IPF risk overall. Efforts in risk profiling or the development of therapies for IPF that focus on TERT, RTEL1, common variants, and environmental risk factors are likely to have the largest impact on this complex disease.

Candidate Role for Toll-like Receptor 3 L412F Polymorphism and Infection in Acute Exacerbation of Idiopathic Pulmonary Fibrosis.

Rationale: The Toll-like receptor 3 Leu412Phe (TLR3 L412F) polymorphism attenuates cellular antiviral responses and is associated with accelerated disease progression in idiopathic pulmonary fibrosis (IPF). The role of TLR3 L412F in bacterial infection in IPF or in acute exacerbations (AE) has not been reported. Objectives: To characterize the association between TLR3 L412F and AE-related death in IPF. To determine the effect of TLR3 L412F on the lung microbiome and on antibacterial TLR responses of primary lung fibroblasts from patients with IPF. Methods: TLR-mediated antibacterial and antiviral responses were quantitated in L412F wild-type and 412F-heterozygous primary lung fibroblasts from patients with IPF using ELISA, Western blot analysis, and quantitative PCR. Hierarchical heatmap analysis was employed to establish bacterial and viral clustering in nasopharyngeal lavage samples from patients with AE-IPF. 16S ribosomal RNA quantitative PCR and pyrosequencing were used to determine the effect of TLR3 L412F on the IPF lung microbiome. Measurements and Main Results: A significant increase in AE-related death in patients with 412F-variant IPF was reported. We established that 412F-heterozygous IPF lung fibroblasts have reduced antibacterial TLR responses to LPS (TLR4), Pam3CYSK4 (TLR1/2), flagellin (TLR5), and FSL-1 (TLR6/1) and have reduced responses to live Pseudomonas aeruginosa infection. Using 16S ribosomal RNA sequencing, we demonstrated that 412F-heterozygous patients with IPF have a dysregulated lung microbiome with increased frequencies of Streptococcus and Staphylococcus spp. Conclusions: This study reveals that TLR3 L412F dysregulates the IPF lung microbiome and reduces the responses of IPF lung fibroblasts to bacterial TLR agonists and live bacterial infection. These findings identify a candidate role for TLR3 L412F in viral- and bacterial-mediated AE death.

Aerosolized drug-loaded nanoparticles targeting migration inhibitory factors inhibit Pseudomonas aeruginosa-induced inflammation and biofilm formation.

Aim: Macrophage migration inhibitory factor (MIF) is a pro-inflammatory cytokine, which has been shown to promote disease severity in cystic fibrosis. Methods: In this study, aerosolized drug-loaded nanoparticles containing SCD-19, an inhibitor of MIF's tautomerase enzymatic activity, were developed and characterized. Results: The aerosolized nanoparticles had an optimal droplet size distribution for deep lung deposition, with a high degree of biocompatibility and significant cellular uptake. Conclusion: For the first time, we have developed an aerosolized nano-formulation against MIF's enzymatic activity that achieved a significant reduction in the inflammatory response of macrophages, and inhibited Pseudomonas aeruginosa biofilm formation on airway epithelial cells. This represents a potential novel adjunctive therapy for the treatment of P. aeruginosa infection in cystic fibrosis.

Detection of Hepatitis E Virus Antibodies in Dogs in the United Kingdom.

Hepatitis E virus (HEV) genotypes 3 and 4 are zoonotic pathogens, with pigs predominantly implicated in disease transmission. The rapid rise in human cases in developed countries over the past decade indicates a change in epidemiology of HEV, and it has been suggested that additional animal species may be involved in transmission of infection. Multiple studies have identified contact with dogs as a risk factor for HEV infection in industrialised nations, and a low seroprevalence to HEV has previously been reported in dogs in low-income countries. In this study we aimed to evaluate the possibility that dogs are susceptible to HEV, and determine the frequency with which this occurs. Serum samples from UK dogs with and without hepatitis were screened for HEV-specific antibodies, and canine liver and stool samples were analysed by qPCR for the presence of HEV RNA. We describe evidence to show HEV infection occurs at low levels in dogs in the UK, but the strain of origin is undetermined. The low seroprevalence level of HEV in dogs implies the risk of zoonotic disease transmission is likely to be limited, but further investigations will be required to determine if HEV-infected dogs can transmit HEV to man.