Pulmonology
Abstract
Intravenous administration of a high affinity carbon monoxide (CO)-binding molecule, recombinant neuroglobin, can improve survival in CO poisoning mouse models. The current study aims to understand how biochemical variables of the scavenger determine the CO removal from the RBCs by evaluating three readily available hemoproteins, 2,3-diphosphoglycerate stripped human hemoglobin (StHb), N-ethylmaleimide modified hemoglobin (NEMHb), and equine myoglobin (Mb). These molecules efficiently sequester CO from hemoglobin in erythrocytes in vitro. A kinetic model was developed to predict the CO binding efficacy for hemoproteins, based on their measured in vitro oxygen and CO binding affinities, suggesting that the therapeutic efficacy of hemoproteins for CO poisoning relates to a high M value, which is the binding affinity for CO relative to oxygen (KA,CO/KA,O2). In a lethal CO poisoning mouse model, StHb, NEMHb, and Mb improved survival by 100%, 100%, and 60%, respectively, compared with saline controls, and were well tolerated in 48-hour toxicology assessments. In conclusion, both StHb and NEMHb have high CO binding affinities and M values and scavenge CO efficiently in vitro and in vivo, highlighting their therapeutic potential for point-of-care antidotal therapy of CO poisoning.
Authors
Qinzi Xu, Jason J. Rose, Xiukai Chen, Ling Wang, Anthony W. DeMartino, Matthew R. Dent, Sagarika Tiwari, Kaitlin Bocian, Xueyin N. Huang, Qin Tong, Charles F. McTiernan, Lanping Guo, Elmira Alipour, Trevor C. Jones, Kamil Burak Ucer, Daniel B. Kim-Shapiro, Jesus Tejero, Mark T. Gladwin
Abstract
Pulmonary fibrosis is a chronic and progressive interstitial lung disease associated with the decay of pulmonary function leading to a fatal outcome. As an essential epigenetic regulator of DNA methylation, the involvement of Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1) in fibroblast activation remains largely undefined in pulmonary fibrosis. In the present study, we found that growth factor–β1(TGF-β1)-mediated upregulation of UHRF1 repressed Beclin1 via its promoter methylation induction which finally results in fibroblast activation and lung fibrosis both in vitro and in vivo. Moreover, knockdown of UHRF1 significantly arrested fibroblast proliferation and reactivated Beclin 1 in lung fibroblasts. Henceforth, intravenous administration of UHRF1 siRNA-loaded liposomes significantly protected mice against experimental pulmonary fibrosis. Accordingly, our data suggested that UHRF1 might be a novel potential therapeutic target in the pathogenesis of pulmonary fibrosis.
Authors
Demin Cheng, Yue Wang, Ziwei Li, Haojie Xiong, Wenqing Sun, Sichuan Xi, Siyun Zhou, Yi Liu, Chunhui Ni
Abstract
Bronchiolitis obliterans syndrome (BOS) is the main reason for poor outcomes after lung transplantation (LTx). We and others have recently identified B cells as major contributors to BOS after LTx. The extent of B cell heterogeneity and the relative contributions of B cell subpopulations to BOS, however, remain unclear. Here, we provide a comprehensive analysis of cell population changes and their gene expression patterns during chronic rejection after orthotopic LTx in mice. Of 11 major cell types, Mzb1-expressing plasma cells (PCs) were the most prominently increased population in BOS lungs. These findings were validated in 2 different cohorts of human BOS after LTx. A Bhlhe41, Cxcr3, and Itgb1 triple-positive B cell subset, also expressing classical markers of the innate-like B-1 B cell population, served as the progenitor pool for Mzb1+ PCs. This subset accounted for the increase in IgG2c production within BOS lung grafts. A genetic lack of Igs decreased BOS severity after LTx. In summary, we provide a detailed analysis of cell population changes during BOS. IgG+ PCs and their progenitors — an innate B cell subpopulation — are the major source of local Ab production and a significant contributor to BOS after LTx.
Authors
Natalia F. Smirnova, Kent Riemondy, Marta Bueno, Susan Collins, Pavan Suresh, Xingan Wang, Kapil N. Patel, Carlyne Cool, Melanie Königshoff, Nirmal S. Sharma, Oliver Eickelberg
Abstract
Obesity-induced asthma responds poorly to all current pharmacological interventions, including steroids; suggesting that classic, eosinophilic inflammation is not a mechanism. As insulin resistance and hyperinsulinemia are common in obese individuals and associated with increased risk of asthma, we used diet-induced obese mice to study how insulin induces airway hyperreactivity. Inhaled 5-HT or methacholine induced dose dependent bronchoconstriction that was significantly potentiated in obese mice. Cutting the vagus nerves eliminated bronchoconstriction in both obese and non-obese animals indicating it was mediated by a neural reflex. There was significantly greater density of airway sensory nerves in obese than in non-obese mice. Deleting insulin receptors on sensory nerves prevented the increase in sensory nerve density and prevented airway hyperreactivity in obese mice with hyperinsulinemia. Our data demonstrate that high levels of insulin drives obesity-induced airway hyperreactivity by increasing sensory innervation of the lung. Therefore, pharmacological interventions to control metabolic syndrome and limit reflex-mediated bronchoconstriction may be a more effective approach to reduce asthma exacerbations in obese and asthmatic patients.
Authors
Gina N. Calco, Jessica N. Maung, David B. Jacoby, Allison D. Fryer, Zhenying Nie
Abstract
A central feature of progressive vascular remodeling is altered smooth muscle cell (SMC) homeostasis; however, the understanding of how different cell populations contribute to this process is limited. Here, we utilized single cell RNA sequencing to provide insight into cellular composition changes within isolated pulmonary arteries (PA) from pulmonary arterial hypertension (PAH) and donor lungs. Our results revealed that remodeling skewed the balanced communication network between immune and structural cells, in particular SMC. Comparative analysis with murine PA showed that human PA harbor heterogeneous SMC populations with an abundant intermediary cluster displaying a gradient transition between SMC and adventitial fibroblasts. Transcriptionally distinct SMC populations were enriched in specific biological processes and could be distinguished into four major clusters: oxygen sensing (enriched in pericytes), contractile, synthetic and fibroblast-like. End-stage remodeling was associated with phenotypic shift of pre-existing SMC populations and accumulation of synthetic SMC in neointima. Distinctly regulated genes in clusters built non-redundant regulatory hubs encompassing stress response and differentiation regulators. The current study provides a blueprint of cellular and molecular changes on a single cell level that are defining pathological vascular remodeling process.
Authors
Slaven Crnkovic, Francesco Valzano, Elisabeth Fließer, Juergen Gindlhuber, Helene Thekkekara Puthenparampil, Maria C. Basil, Michael P. Morley, Jeremy Katzen, Elisabeth Gschwandtner, Walter Klepetko, Edward Cantu, Heimo Wolinski, Horst Olschewski, Jorg Lindenmann, You-Yang Zhao, Edward E. Morrisey, Leigh M. Marsh, Grazyna Kwapiszewska
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic disease of unmet medical need. It is characterized by formation of scar tissue leading to a progressive and irreversible decline in lung function. IPF is associated with repeated injury, which may alter the composition of the extracellular matrix (ECM). Here, we demonstrate that IPF patient–derived pulmonary ECM drives profibrotic response in normal human lung fibroblasts (NHLF) in a 3D spheroid assay. Next, we reveal distinct alterations in composition of the diseased ECM, identifying potentially novel associations with IPF. Growth differentiation factor 15 (GDF15) was identified among the most significantly upregulated proteins in the IPF lung–derived ECM. In vivo, GDF15 neutralization in a bleomycin-induced lung fibrosis model led to significantly less fibrosis. In vitro, recombinant GDF15 (rGDF15) stimulated α smooth muscle actin (αSMA) expression in NHLF, and this was mediated by the activin receptor-like kinase 5 (ALK5) receptor. Furthermore, in the presence of rGDF15, the migration of NHLF in collagen gel was reduced. In addition, we observed a cell type–dependent effect of GDF15 on the expression of cell senescence markers. Our data suggest that GDF15 mediates lung fibrosis through fibroblast activation and differentiation, implicating a potential direct role of this matrix-associated cytokine in promoting aberrant cell responses in disease.
Authors
Agata Radwanska, Christopher Travis Cottage, Antonio Piras, Catherine Overed-Sayer, Carina Sihlbom, Ramachandramouli Budida, Catherine Wrench, Jane Connor, Susan Monkley, Petra Hazon, Holger Schluter, Matthew J. Thomas, Cory M. Hogaboam, Lynne A. Murray
Abstract
Chitinase 3-like 1 (CHI3L1) is the prototypic chitinase-like protein mediating inflammation, cell proliferation, and tissue remodeling. Limited data suggests CHI3L1 is elevated in human pulmonary arterial hypertension (PAH) and is associated with disease severity. Despite its importance as a regulator of injury/repair responses, the relationship between CHI3L1 and pulmonary vascular remodeling is not well understood. We hypothesize that CHI3L1 and its signaling pathways contribute to the vascular remodeling responses that occur in pulmonary hypertension (PH). We examined the relationship of plasma CHI3L1 levels and severity of PH in patients with various forms of PH, including Group 1 PAH and Group 3 PH, and found that circulating levels of serum CHI3L1 were associated with worse hemodynamics and correlated directly with mean pulmonary artery pressure and pulmonary vascular resistance. We also used transgenic mice with constitutive knockout and inducible overexpression of CHI3L1 to examine its role in hypoxia-, monocrotaline-, and bleomycin-induced models of pulmonary vascular disease. In all 3 mouse models of pulmonary vascular disease, pulmonary hypertensive responses were mitigated in CHI3L1 null mice and accentuated in transgenic mice that overexpress CHI3L1. Finally, CHI3L1 alone was sufficient to induce pulmonary arterial smooth muscle cell proliferation, inhibit pulmonary vascular endothelial cell apoptosis, induce the loss of endothelial barrier function, and induce endothelial-to-mesenchymal transition. These findings demonstrate that CHI3L1 and its receptors play an integral role in pulmonary vascular disease pathobiology and may offer a novel target for the treatment PAH and PH associated with fibrotic lung disease.
Authors
Xiuna Sun, Erika Nakajima, Carmelissa Norbrun, Parand Sorkhdini, Alina Xiaoyu Yang, Dongqin Yang, Corey E. Ventetuolo, Julie Braza, Alexander Vang, Jason Aliotta, Debasree Banerjee, Mandy Pereira, Grayson Baird, Qing Lu, Elizabeth O. Harrington, Sharon Rounds, Chun Geun Lee, Hongwei Yao, Gaurav Choudhary, James R. Klinger, Yang Zhou
Abstract
Increased red cell distribution width (RDW), which measures erythrocyte volume (MCV) variability (anisocytosis), has been linked to early mortality in many diseases and in older adults through unknown mechanisms. Hypoxic stress has been proposed as a potential mechanism. However, experimental models to investigate the link between increased RDW and reduced survival are lacking. Here, we show that lifelong hypobaric hypoxia (~10% O2) increases erythrocyte numbers, hemoglobin and RDW, while reducing longevity in male mice. Compound heterozygous knockout (chKO) mutations in succinate dehydrogenase (Sdh; mitochondrial complex II) genes Sdhb, Sdhc and Sdhd reduce Sdh subunit protein levels, RDW, and increase healthy lifespan compared to wild-type (WT) mice in chronic hypoxia. RDW-SD, a direct measure of MCV variability, and the standard deviation of MCV (1SD-RDW) show the most statistically significant reductions in Sdh hKO mice. Tissue metabolomic profiling of 147 common metabolites shows the largest increase in succinate with elevated succinate to fumarate and succinate to oxoglutarate (2-ketoglutarate) ratios in Sdh hKO mice. These results demonstrate that mitochondrial complex II level is an underlying determinant of both RDW and healthy lifespan in hypoxia, and suggest that therapeutic targeting of Sdh might reduce high RDW-associated clinical mortality in hypoxic diseases.
Authors
Bora E. Baysal, Abdulrahman A. Alahmari, Tori C. Rodrick, Debra Tabaczynski, Leslie Curtin, Mukund Seshadri, Drew R. Jones, Sandra Sexton
Abstract
There is a paucity of information about potential molecular brakes on the activation of fibroblasts that drive tissue fibrosis. The transcription factor Kruppel-like factor 4 (KLF4) is best known as a determinant of cell stemness and a tumor suppressor. We found that its expression was diminished in fibroblasts from fibrotic lung. Gain- and loss-of-function studies showed that KLF4 inhibits fibroblast proliferation, collagen synthesis, and differentiation to myofibroblasts, while restoring their sensitivity to apoptosis. Conditional deletion of KLF4 from fibroblasts potentiated the peak degree of pulmonary fibrosis and abrogated the subsequent spontaneous resolution that follows in a model of transient fibrosis. A small molecule inducer of KLF4 was able to restore its expression in fibrotic fibroblasts and elicit resolution in an experimental model characterized by more clinically relevant persistent pulmonary fibrosis. These data identify KLF4 as a pivotal brake on fibroblast activation whose induction represents a new therapeutic approach in fibrosis of the lung, and perhaps other organs.
Authors
Loka Raghu Kumar Penke, Jennifer M. Speth, Steven K. Huang, Sean M. Fortier, Jared Baas, Marc Peters-Golden
Abstract
Usual Interstitial Pneumonia (UIP) is a histological pattern characteristic of Idiopathic Pulmonary Fibrosis (IPF). The UIP pattern is patchy with histologically normal lung adjacent to dense fibrotic tissue. At this interface, fibroblastic foci (FF) are present and are sites where myofibroblasts and extracellular matrix (ECM) accumulate. Utilizing laser capture microdissection coupled mass spectrometry (LCM-MS), we interrogated the FF, adjacent mature scar, and adjacent alveoli in 6 fibrotic (UIP/IPF) specimens plus 6 non-fibrotic alveolar specimens as controls. The data were subject to qualitative and quantitative analysis, and histologically validated. We found that the fibrotic alveoli protein signature is defined by immune deregulation as the strongest category. The fibrotic mature scar classified as end-stage fibrosis whereas the FF contained an overabundance of a distinctive ECM compared to non-fibrotic control. Furthermore, the FF is positive for both TGFB1 and TGFB3, whereas the aberrant basaloid cell lining of the FF is predominantly positive for TGFB2. In conclusion, spatial proteomics demonstrated distinct protein compositions in the histologically defined regions of UIP/IPF tissue. These data revealed that the FF is the main site of collagen biosynthesis and that the adjacent alveoli are abnormal. This new and essential information will inform future mechanistic studies on fibrosis progression.
Authors
Jeremy A. Herrera, Lewis A. Dingle, M. Angeles Montero Fernandez, Rajamiyer V. Venkateswaran, John F. Blaikley, Craig Lawless, Martin A. Schwartz
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