The relationship between complement C3 expression and the MUC5B genotype in pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a lung parenchymal disease of unknown cause usually occurring in older adults. It is a chronic and progressive condition with poor prognosis and diagnosis is largely clinical. Currently, there exist few biomarkers that can predict patient outcome or response to therapies. Together with lack of markers, the need for novel markers for the detection and monitoring of IPF, is paramount. We have performed label-free plasma proteomics of thirty six individuals, 17 of which had confirmed IPF. Proteomics data was analyzed by volcano plot, hierarchical clustering, Partial-least square discriminant analysis (PLS-DA) and Ingenuity pathway analysis. Univariate and multivariate statistical analysis overlap identified haptoglobin-related protein as a possible marker of IPF when compared to control samples (Area under the curve 0.851, ROC-analysis). LXR/RXR activation and complement activation pathways were enriched in t-test significant proteins and oxidative regulators, complement proteins and protease inhibitors were enriched in PLS-DA significant proteins. Our pilot study points towards aberrations in complement activation and oxidative damage in IPF patients and provides haptoglobin-related protein as a new candidate biomarker of IPF. Idiopathic pulmonary fibrosis is chronic, progressive, interstitial pneumonia of unknown cause usually occurring in older adults and presents with usual interstitial pneumonia (UIP) in histopathological and/or radiological findings. Current data suggests that the incidence of IPF has been increasing in some parts of the world including Europe 1. The diagnosis of IPF is largely clinical and radiological and laboratory investigations are often not helpful although they can be used to rule out other conditions. The common symptoms include breathlessness on exertion, decreasing pulmonary function, bibasilar inspiratory crackles and finger clubbing in 50% of the patients 2-4. Decline in respiratory function can be slow and progressive or rapid and accelerated giving rise to variable survival pattern. Damage in IPF is usually irreversible and unpredictable and prognosis is extremely poor 2-4. According to collaborative efforts of the American Thoracic Society, the European Respiratory Society, the Japanese Respiratory Society, and the Latin American Thoracic Association, diagnosis requires exclusion of other known causes of interstitial lung disease (environmental exposure, drug toxicities and connective tissue

Idiopathic pulmonary fibrosis (IPF) is a progressive and heterogeneous interstitial lung disease of unknown origin with a low survival rate. There are few treatment options available due to the fact that mechanisms underlying disease progression are not well understood, likely because they arise from dysregulation of complex signaling networks spanning multiple tissue compartments. To better characterize these networks, we used systems-focused data-driven modeling approaches to identify cross-tissue compartment (blood and bronchoalveolar lavage) and temporal proteomic signatures that differentiated IPF progressors and non-progressors. Partial least squares discriminant analysis identified a signature of 54 baseline (week 0) blood and lung proteins that differentiated IPF progression status by the end of 80 weeks of follow-up with 100% cross-validation accuracy. Overall we observed heterogeneous protein expression patterns in progressors compared to more homogenous signatures in non-progressors, and found that non-progressors were enriched for proteomic processes involving regulation of the immune/defense response. We also identified a temporal signature of blood proteins that was significantly different at early and late progressor time points (p < 0.0001), but not present in non-progressors. Overall, this approach can be used to generate new hypothesis for mechanisms associated with IPF progression and could readily be translated to other complex and heterogeneous diseases. Idiopathic pulmonary fibrosis (IPF) is a heterogeneous and irreversible interstitial pneumonia, with symptoms including progressive cough, shortness of breath, and ultimately respiratory failure, with a median survival of only 3-5 years post diagnosis 1. The disease is believed to be caused by a dysregulated wound healing response to various epithelial injuries leading to fibrosis of the lung interstitium 1. Two medications (nintedanib 2 and pirfenidone 3) are effective treatments for IPF; though neither can reverse the disease 4. Thus, lung transplantation is currently the only option for a cure 5 , even though this procedure has the highest failure rate of all organ transplantation options (54% at 5 years 6). Better understanding of mechanisms underpinning progression of pulmonary fibrosis could lead to improved outcomes via identification of new therapeutic targets. To add to the complexity surrounding IPF, disease progression is also heterogeneous, with some individual patients experiencing long-term stability and others rapid loss of lung function. A number of longitudinal cohort studies have been created with the goal of better characterizing IPF pathobiology using proteomic measurements 7-10. These efforts have identified individual proteins, including blood MMP-7 11,12 , CCL18 13 , and blood surfactant protein D 14,15 , as potential prognostic biomarkers. However, it has been difficult to replicate these findings across multiple cohorts 16,17 , especially when attempting to validate specific, prognostically-relevant cutoff concentrati...

Neutrophilic inflammation correlates with mortality in fibrotic interstitial lung disease (ILD) however, the underlying mechanisms remain unclear. We aimed to determine whether aberrant neutrophil activation is a feature of ILD and the relative role of hypoxia. We used lung biopsies and bronchoalveolar lavage (BAL) from ILD patients to investigate the extent of hypoxia and neutrophil activation in lungs of patients with ILD. We complemented these findings with ex vivo functional studies of neutrophils from healthy volunteers to determine the effects of hypoxia. We demonstrate for the first time HIF-1α staining in neutrophils and endothelial cells in ILD lung biopsies. Hypoxia enhanced both spontaneous and phorbol 12myristate 13-acetate (PMA)-induced neutrophil extracellular trap (NET) release (NETosis), neutrophil adhesion, and trans-endothelial migration. Hypoxia also increased neutrophil expression of the α M and α X integrin subunits. Interestingly, NETosis was induced by α M β 2 integrin activation and prevented by cation chelation. Finally, NETs were demonstrated in the BAL from ILD patients, and quantification showed significantly increased cell-free DNA content and MPO-citrullinated histone H3 complexes in ILD patients compared to non-ILD controls. Our work indicates that HIF-1α upregulation may augment neutrophil recruitment and activation within the lung interstitium through activation of β 2 integrins. Our results identify a novel HIF-1α-Integrin-NETosis axis for future exploration in therapeutic approaches to fibrotic ILD.