Pulmonology
Abstract
Alpha-1 antitrypsin (AAT) deficiency (AATD) is the most common genetic cause and risk factor for chronic obstructive pulmonary disease, but the field lacks a large animal model that allows for longitudinal assessment of pulmonary function. We hypothesized that ferrets would model human AATD-related lung and hepatic disease. AAT-knockout (AAT-KO) and PiZZ (E342K, the most common mutation in humans) ferrets were generated and compared to matched controls using custom-designed flexiVent modules to perform pulmonary function tests (PFTs), quantitative computed tomography (QCT), bronchoalveolar lavage (BAL) proteomics, and alveolar morphometry. Complete loss of AAT (AAT-KO) led to increased pulmonary compliance and expiratory airflow limitation, consistent with obstructive lung disease. QCT and morphometry confirmed emphysema and airspace enlargement, respectively. Pathway analysis of BAL proteomics data revealed inflammatory lung disease and impaired cellular migration. The PiZ mutation resulted in altered AAT protein folding in the liver, hepatic injury, reduced plasma concentrations of AAT, and PiZZ ferrets developed obstructive lung disease. In summary, AAT-KO and PiZZ ferrets model the progressive obstructive pulmonary disease seen in AAT-deficient patients and may serve as a platform for preclinical testing of therapeutics including gene therapy.
Authors
Nan He, Xiaoming Liu, Amber R. Vegter, T. Idil A. Evans, Jaimie S. Gray, Junfeng Guo, Shashanna R. Moll, Lydia J. Guo, Meihui Luo, Ningxia Ma, Xingshen Sun, Bo Liang, Ziying Yan, Zehua Feng, Lisi Qi, Arnav S. Joshi, Weam Shahin, Yaling Yi, Katherine N. Gibson-Corley, Eric A. Hoffman, Kai Wang, Christian Mueller, John F. Engelhardt, Bradley H. Rosen
Abstract
COPD is a debilitating chronic disease and the third cause of mortality worldwide. It is characterized by airway neutrophilia, promoting tissue injury through release of toxic mediators and proteases. Recently, it has been shown that neutrophil-derived extracellular vesicles (EVs) from COPD patient lungs can cause a neutrophil elastase (NE)-dependent COPD-like disease upon transfer to mouse airways. However in vivo preclinical models elucidating the impact of EVs on disease are lacking, delaying opportunities for therapeutic testing. Here, we developed an in vivo preclinical mouse model of lung EV-induced COPD. EVs from in vivo LPS activated mouse neutrophils induced COPD-like disease in naive recipients through an alpha-1 antitrypsin resistant, NE-dependent mechanism. Together, these results show a key pathogenic and mechanistic role for neutrophil-derived EVs in a new mouse model of COPD. Broadly, the in vivo model described herein could be leveraged to develop targeted therapies for severe lung disease.
Authors
Camilla Margaroli, Matthew C. Madison, Liliana Viera, Derek W. Russell, Amit Gaggar, Kristopher R. Genschmer, J. Edwin Blalock
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal disease characterized by collagen deposition within the lung interstitium. Bacterial infection is associated with increased morbidity and more rapid mortality in IPF patient populations and pathogens such as methicillin-resistant Staphylococcus aureus (MRSA) are commonly isolated from the lungs of hospitalized IPF patients. Despite this, the effects of fibrotic lung injury on critical immune responses to infection remain unknown. In the present study, we show that, like human IPF, fibrotic mice infected with MRSA exhibit increased morbidity and mortality compared to uninfected fibrotic mice. We determine that fibrosis confers a defect in MRSA clearance compared to non-fibrotic mice, resulting from blunted innate immune responses. We show that fibrosis inhibits neutrophil intracellular killing of MRSA through impaired neutrophil elastase (NE) release and oxidative radical production. Additionally, we demonstrate that lung macrophages from fibrotic mice have impaired phagocytosis of MRSA. Our study describes potentially novel impairments to antimicrobial responses upon the development of pulmonary fibrosis and our findings suggest a possible mechanism for why IPF patients are at greater risk of morbidity and mortality related to infection.
Authors
Helen I. Warheit-Niemi, Summer J. Edwards, Shuvasree SenGupta, Carole A. Parent, Xiaofeng Zhou, David N. O'Dwyer, Bethany B. Moore
Abstract
Fibroproliferative disorders such as systemic sclerosis (SSc) have no effective therapies and result in significant morbidity and mortality. We recently demonstrated that the C-terminal domain of endostatin, known as E4, prevented and reversed both dermal and pulmonary fibrosis. Our goal was to identify the mechanism by which E4 abrogates fibrosis and its cell surface binding partner(s). Our findings show that E4 activated the urokinase pathway and increased the urokinase plasminogen activator (uPA) to type 1 plasminogen activator inhibitor (PAI-1) ratio. In addition, E4 substantially increased MMP-1 and MMP-3 expression and activity. In vivo, E4 reversed bleomycin induction of PAI-1 and increased uPA activity. In patients with SSc, the uPA/PAI-1 ratio was decreased in both lung tissues and pulmonary fibroblasts compared with normal donors. Proteins bound to biotinylated-E4 were identified as enolase-1 (ENO) and uPA receptor (uPAR). The antifibrotic effects of E4 required uPAR. Further, ENO mediated the fibrotic effects of TGF-β1 and exerted TGF-β1–independent fibrotic effects. Our findings suggest that the antifibrotic effect of E4 is mediated, in part, by regulation of the urokinase pathway and induction of MMP-1 and MMP-3 levels and activity in a uPAR-dependent manner, thus promoting extracellular matrix degradation. Further, our findings identify a moonlighting function for the glycolytic enzyme ENO in fibrosis.
Authors
Shailza Sharma, Tomoya Watanabe, Tetsuya Nishimoto, Takahisa Takihara, Logan Mlakar, Xinh-Xinh Nguyen, Matthew Sanderson, Yunyun Su, Roger A. Chambers, Carol Feghali-Bostwick
Abstract
Acute Respiratory Distress Syndrome (ARDS) is a common cause of respiratory failure yet has few pharmacologic therapies, reflecting the mechanistic heterogeneity of lung injury. We hypothesized that damage to the alveolar epithelial glycocalyx, a layer of glycosaminoglycans interposed between the epithelium and surfactant, contributes to lung injury in ARDS patients. Using mass spectrometry of airspace fluid noninvasively collected from mechanically-ventilated patients, we found that airspace glycosaminoglycan shedding (an index of glycocalyx degradation) occurred predominantly in patients with direct lung injury and was associated with duration of mechanical ventilation. Male patients had increased shedding which correlated with airspace concentrations of matrix metalloproteinases. Selective epithelial glycocalyx degradation in mice was sufficient to induce surfactant dysfunction, a key characteristic of ARDS, leading to microatelectasis and decreased lung compliance. Rapid colorimetric quantification of airspace glycosaminoglycans was feasible and could provide point-of-care prognostic information to clinicians and/or be used for predictive enrichment in clinical trials.
Authors
Alicia N. Rizzo, Sarah M. Haeger, Kaori Oshima, Yimu Yang, Alison M. Wallbank, Ying Jin, Marie Lettau, Lynda A. McCaig, Nancy E. Wickersham, J. Brennan McNeil, Igor Zakharevich, Sarah A. McMurtry, Christophe J. Langouët-Astrié, Katrina W. Kopf, Dennis R. Voelker, Kirk C. Hansen, Ciara M. Shaver, V. Eric Kerchberger, Ryan A. Peterson, Wolfgang M. Kuebler, Matthias Ochs, Ruud A.W. Veldhuizen, Bradford J. Smith, Lorraine B. Ware, Julie A. Bastarache, Eric P. Schmidt
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with limited treatment options. Despite endothelial cells (ECs) comprising 30% of the lung cellular composition, the role of EC dysfunction in pulmonary fibrosis (PF) remains unclear. We hypothesize that sterol regulatory element-binding protein 2 (SREBP2) plays a critical role in the pathogenesis of PF via EC phenotypic modifications. Transcriptome data demonstrate that SREBP2 overexpression in ECs led to the induction of the TGF, Wnt, and cytoskeleton remodeling gene ontology pathways and the increased expression of mesenchymal genes, such as snail family transcriptional repressor 1 (snai1), α-smooth muscle actin, vimentin, and neural cadherin. Furthermore, SREBP2 directly bound to the promoter regions and transactivated these mesenchymal genes. This transcriptomic change was associated with an epigenetic and phenotypic switch in ECs, leading to increased proliferation, stress fiber formation, and ECM deposition. Mice with endothelial-specific transgenic overexpression of SREBP2 (EC-SREBP2[N]-Tg mice) that were administered bleomycin to induce PF demonstrated exacerbated vascular remodeling and increased mesenchymal transition in the lung. SREBP2 was also found to be markedly increased in lung specimens from patients with IPF. These results suggest that SREBP2, induced by lung injury, can exacerbate PF in rodent models and in human patients with IPF.
Authors
Marcy Martin, Jiao Zhang, Yifei Miao, Ming He, Jian Kang, Hsi-Yuan Huang, Chih-Hung Chou, Tse-Shun Huang, Hsiao-Chin Hong, Shu-Han Su, Simon S. Wong, Rebecca L. Harper, Lingli Wang, Rakesh Bhattacharjee, Hsien-Da Huang, Zhen Bouman Chen, Atul Malhotra, Marlene Rabinovitch, James S. Hagood, John Y-J. Shyy
Abstract
Lung allograft rejection results in the accumulation of low molecular weight hyaluronic acid (LMW-HA), which further propagates inflammation and tissue injury. We have previously shown that therapeutic lymphangiogenesis in a murine model of lung allograft rejection reduced tissue LMW-HA and was associated with improved transplant outcomes. Herein we investigated the use of 4-Methylumbelliferone, a known inhibitor of HA synthesis, to alleviate acute allograft rejection in a murine model of lung transplantation. We found that treating mice with 4MU from day 20-30 post-transplant was sufficient to significantly improve outcomes, characterized by a reduction in T-cell mediated lung inflammation, LMW-HA content, and improved pathology scores. In vitro, 4MU directly attenuated activation, proliferation, and differentiation of naïve CD4+ T-cells into Th1 cells. As 4MU has already been demonstrated to be safe for human use, we believe examining 4MU for the treatment of acute lung allograft rejection may be of clinical significance.
Authors
Jewel Imani, Kaifeng Liu, Ye Cui, Jean-Pierre Assaker, Junwen Han, Auyon J. Ghosh, Julie Ng, Shikshya Shrestha, Anthony M. Lamattina, Pierce H. Louis, Anne Hentschel, Anthony J. Esposito, Ivan O. Rosas, Xiaoli Liu, Mark A. Perrella, Jamil Azzi, Gary Visner, Souheil El-Chemaly
Abstract
Asthma is a common disease with profoundly variable natural history and patient morbidity. Heterogeneity has long been appreciated and much work has focused on identifying subgroups of patients with similar pathobiological underpinnings. Previous studies of the Severe Asthma Research Program (SARP) cohort linked gene expression changes to specific clinical and physiologic characteristics. While invaluable for hypothesis generation, these data include extensive candidate gene lists that complicate target identification and validation. In this analysis, we performed unsupervised clustering of the SARP cohort using bronchial epithelial cell gene expression data, identifying a transcriptional signature for participants suffering exacerbation prone asthma with impaired lung function. Clinically, participants in this asthma cluster exhibited a mixed inflammatory process and bore transcriptional hallmarks of nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1) activation despite high corticosteroid exposure. Using supervised machine learning, we found a set of 31 genes that classified patients with high accuracy and could reconstitute clinical and transcriptional hallmarks of our patient clustering in an external cohort. Of these genes, IL18R1 (IL-18 Receptor 1) negatively associated with lung function and was highly expressed in the most severe patient cluster. We validated IL18R1 protein expression in lung tissue and identified downstream NF-κB and AP-1 activity, supporting IL-18 signaling in severe asthma pathogenesis and highlighting this approach for gene/pathway discovery.
Authors
Matthew J. Camiolo, Xiuxia Zhou, Qi Wei, Humberto E. Trejo Bittar, Naftali Kaminski, Anuradha Ray, Sally Wenzel
Abstract
Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disease associated with unremitting fibroblast activation including fibroblast-to-myofibroblast transformation (FMT), migration, resistance to apoptotic clearance, and excessive deposition of extracellular matrix (ECM) proteins in the distal lung parenchyma. Aberrant activation of lung-developmental pathways is associated with severe fibrotic lung disease; however, the mechanisms through which these pathways activate fibroblasts in IPF remain unclear. Sox9 is a member of the HMG box family of DNA-binding transcription factors that are selectively expressed by epithelial cell progenitors to modulate branching morphogenesis during lung development. We demonstrate that Sox9 is upregulated via MAPK/PI3K-dependent signaling and by the transcription factor Wilms’ tumor 1 in distal lung-resident fibroblasts in IPF. Mechanistically, using fibroblast activation assays, we demonstrate that Sox9 functions as a positive regulator of FMT, migration, survival, and ECM production. Importantly, our in vivo studies demonstrate that fibroblast-specific deletion of Sox9 is sufficient to attenuate collagen deposition and improve lung function during TGFα-induced pulmonary fibrosis. Using a mouse model of bleomycin-induced pulmonary fibrosis, we show that myofibroblast-specific Sox9 overexpression augments fibroblast activation and pulmonary fibrosis. Thus, Sox9 functions as a profibrotic transcription factor in activating fibroblasts, illustrating the potential utility of targeting Sox9 in IPF treatment.
Authors
Prathibha R. Gajjala, Rajesh K. Kasam, Divyalakshmi Soundararajan, Debora Sinner, Steven K. Huang, Anil G. Jegga, Satish K. Madala
Abstract
Pulmonary hypertension (PH) is a severe cardiopulmonary disease characterized by complement-dependent, fibroblast-induced perivascular accumulation and pro-inflammatory activation of macrophages. We hypothesized that, in PH, nanoscale-sized small extracellular vesicles (sEVs), released by perivascular/adventitial fibroblasts, are critical mediators of complement-dependent pro-inflammatory activation of macrophages. Pulmonary adventitial fibroblasts were isolated from calves with severe PH (PH-Fibs) and age-matched controls (CO-Fibs). PH-Fibs exhibited increased secretion of sEVs, compared to CO-Fibs, and sEV biological activity was tested on mouse and bovine bone marrow-derived macrophages (BMDMs) and showed similar responses. PH-Fib-sEVs induced augmented expression of pro-inflammatory cytokines/chemokines and metabolic genes in BMDMs, compared to CO-Fib-sEVs. Pharmacological blockade of exosome release from PH-Fibs resulted in significant attenuation of pro-inflammatory activation of BMDMs. “Bottom-up” proteomic analyses revealed significant enrichment of complement and Coagulation cascades in PH-Fib-sEVs, including augmented expression of complement component C3. We therefore examined whether PH-Fib-sEVs-mediated pro-inflammatory activation of BMDMs was complement C3-dependent. Treatment of PH-Fibs with siC3-RNA significantly attenuated the capacity of PH-Fib-sEVs for pro-inflammatory activation of BMDMs. PH-Fib-sEVs mediated pro-glycolytic alterations and complement-dependent activation of macrophages toward a pro-inflammatory phenotype, as confirmed by metabolomic studies. Thus, fibroblast-released sEVs can serve as critical mediators of complement-induced perivascular/microenvironmental inflammation in PH.
Authors
Sushil Kumar, Maria G. Frid, Hui Zhang, Min Li, Suzette Riddle, R. Dale Brown, Subhash Chandra Yadav, Micaela K. Roy, Monika E. Dzieciatkowska, Angelo D’Alessandro, Kirk C. Hansen, Kurt R. Stenmark
No posts were found with this tag.
