Browsing by Subject "Respiratory System"
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Item Open Access Airway basal stem cells: a perspective on their roles in epithelial homeostasis and remodeling.(Dis Model Mech, 2010-09) Rock, Jason R; Randell, Scott H; Hogan, Brigid LMThe small airways of the human lung undergo pathological changes in pulmonary disorders, such as chronic obstructive pulmonary disease (COPD), asthma, bronchiolitis obliterans and cystic fibrosis. These clinical problems impose huge personal and societal healthcare burdens. The changes, termed 'pathological airway remodeling', affect the epithelium, the underlying mesenchyme and the reciprocal trophic interactions that occur between these tissues. Most of the normal human airway is lined by a pseudostratified epithelium of ciliated cells, secretory cells and 6-30% basal cells, the proportion of which varies along the proximal-distal axis. Epithelial abnormalities range from hypoplasia (failure to differentiate) to basal- and goblet-cell hyperplasia, squamous- and goblet-cell metaplasia, dysplasia and malignant transformation. Mesenchymal alterations include thickening of the basal lamina, smooth muscle hyperplasia, fibrosis and inflammatory cell accumulation. Paradoxically, given the prevalence and importance of airway remodeling in lung disease, its etiology is poorly understood. This is due, in part, to a lack of basic knowledge of the mechanisms that regulate the differentiation, maintenance and repair of the airway epithelium. Specifically, little is known about the proliferation and differentiation of basal cells, a multipotent stem cell population of the pseudostratified airway epithelium. This Perspective summarizes what we know, and what we need to know, about airway basal cells to evaluate their contributions to normal and abnormal airway remodeling. We contend that exploiting well-described model systems using both human airway epithelial cells and the pseudostratified epithelium of the genetically tractable mouse trachea will enable crucial discoveries regarding the pathogenesis of airway disease.Item Open Access Efficacy of Hyperbaric Oxygen for Carbon Monoxide Poisoning.(Chest, 2018-03) Moon, Richard E; Hampson, Neil BItem Open Access Give Me Some Room to Breathe! Can Targeting SPHK2 Reduce Airway Smooth Muscle Thickening in Asthma?(American journal of respiratory cell and molecular biology, 2020-01) Ingram, Jennifer LItem Open Access Interactions of oxygen radicals with airway epithelium.(Environ Health Perspect, 1994-12) Wright, DT; Cohn, LA; Li, H; Fischer, B; Li, CM; Adler, KBReactive oxygen species (ROS) have been implicated in the pathogenesis of numerous disease processes. Epithelial cells lining the respiratory airways are uniquely vulnerable regarding potential for oxidative damage due to their potential for exposure to both endogenous (e.g., mitochondrial respiration, phagocytic respiratory burst, cellular oxidases) and exogenous (e.g., air pollutants, xenobiotics, catalase negative organisms) oxidants. Airway epithelial cells use several nonenzymatic and enzymatic antioxidant mechanisms to protect against oxidative insult. Nonenzymatic defenses include certain vitamins and low molecular weight compounds such as thiols. The enzymes superoxide dismutase, catalase, and glutatione peroxidase are major sources of antioxidant protection. Other materials associated with airway epithelium such as mucus, epithelial lining fluid, and even the basement membrane/extracellular matrix may have protective actions as well. When the normal balance between oxidants and antioxidants is upset, oxidant stress ensues and subsequent epithelial cell alterations or damage may be a critical component in the pathogenesis of several respiratory diseases. Oxidant stress may profoundly alter lung physiology including pulmonary function (e.g., forced expiratory volumes, flow rates, and maximal inspiratory capacity), mucociliary activity, and airway reactivity. ROS may induce airway inflammation; the inflammatory process may serve as an additional source of ROS in airways and provoke the pathophysiologic responses described. On a more fundamental level, cellular mechanisms in the pathogenesis of ROS may involve activation of intracellular signaling enzymes including phospholipases and protein kinases stimulating the release of inflammatory lipids and cytokines. Respiratory epithelium may be intimately involved in defense against, and pathophysiologic changes invoked by, ROS.Item Open Access Overdue to understand anticoagulation in pulmonary arterial hypertension.(Pulmonary circulation, 2018-01) Parikh, Kishan S; Gray, Michael P; Rubin, Lewis J; Badesch, David; Krasuski, Richard AItem Open Access Pathogenic triad in COPD: oxidative stress, protease-antiprotease imbalance, and inflammation.(Int J Chron Obstruct Pulmon Dis, 2011) Fischer, Bernard M; Pavlisko, Elizabeth; Voynow, Judith APatients with chronic obstructive pulmonary disease (COPD) exhibit dominant features of chronic bronchitis, emphysema, and/or asthma, with a common phenotype of airflow obstruction. COPD pulmonary physiology reflects the sum of pathological changes in COPD, which can occur in large central airways, small peripheral airways, and the lung parenchyma. Quantitative or high-resolution computed tomography is used as a surrogate measure for assessment of disease progression. Different biological or molecular markers have been reported that reflect the mechanistic or pathogenic triad of inflammation, proteases, and oxidants and correspond to the different aspects of COPD histopathology. Similar to the pathogenic triad markers, genetic variations or polymorphisms have also been linked to COPD-associated inflammation, protease-antiprotease imbalance, and oxidative stress. Furthermore, in recent years, there have been reports identifying aging-associated mechanistic markers as downstream consequences of the pathogenic triad in the lungs from COPD patients. For this review, the authors have limited their discussion to a review of mechanistic markers and genetic variations and their association with COPD histopathology and disease status.Item Open Access Single-cell meta-analysis of SARS-CoV-2 entry genes across tissues and demographics.(Nature medicine, 2021-03) Muus, Christoph; Luecken, Malte D; Eraslan, Gökcen; Sikkema, Lisa; Waghray, Avinash; Heimberg, Graham; Kobayashi, Yoshihiko; Vaishnav, Eeshit Dhaval; Subramanian, Ayshwarya; Smillie, Christopher; Jagadeesh, Karthik A; Duong, Elizabeth Thu; Fiskin, Evgenij; Torlai Triglia, Elena; Ansari, Meshal; Cai, Peiwen; Lin, Brian; Buchanan, Justin; Chen, Sijia; Shu, Jian; Haber, Adam L; Chung, Hattie; Montoro, Daniel T; Adams, Taylor; Aliee, Hananeh; Allon, Samuel J; Andrusivova, Zaneta; Angelidis, Ilias; Ashenberg, Orr; Bassler, Kevin; Bécavin, Christophe; Benhar, Inbal; Bergenstråhle, Joseph; Bergenstråhle, Ludvig; Bolt, Liam; Braun, Emelie; Bui, Linh T; Callori, Steven; Chaffin, Mark; Chichelnitskiy, Evgeny; Chiou, Joshua; Conlon, Thomas M; Cuoco, Michael S; Cuomo, Anna SE; Deprez, Marie; Duclos, Grant; Fine, Denise; Fischer, David S; Ghazanfar, Shila; Gillich, Astrid; Giotti, Bruno; Gould, Joshua; Guo, Minzhe; Gutierrez, Austin J; Habermann, Arun C; Harvey, Tyler; He, Peng; Hou, Xiaomeng; Hu, Lijuan; Hu, Yan; Jaiswal, Alok; Ji, Lu; Jiang, Peiyong; Kapellos, Theodoros S; Kuo, Christin S; Larsson, Ludvig; Leney-Greene, Michael A; Lim, Kyungtae; Litviňuková, Monika; Ludwig, Leif S; Lukassen, Soeren; Luo, Wendy; Maatz, Henrike; Madissoon, Elo; Mamanova, Lira; Manakongtreecheep, Kasidet; Leroy, Sylvie; Mayr, Christoph H; Mbano, Ian M; McAdams, Alexi M; Nabhan, Ahmad N; Nyquist, Sarah K; Penland, Lolita; Poirion, Olivier B; Poli, Sergio; Qi, CanCan; Queen, Rachel; Reichart, Daniel; Rosas, Ivan; Schupp, Jonas C; Shea, Conor V; Shi, Xingyi; Sinha, Rahul; Sit, Rene V; Slowikowski, Kamil; Slyper, Michal; Smith, Neal P; Sountoulidis, Alex; Strunz, Maximilian; Sullivan, Travis B; Sun, Dawei; Talavera-López, Carlos; Tan, Peng; Tantivit, Jessica; Travaglini, Kyle J; Tucker, Nathan R; Vernon, Katherine A; Wadsworth, Marc H; Waldman, Julia; Wang, Xiuting; Xu, Ke; Yan, Wenjun; Zhao, William; Ziegler, Carly GK; NHLBI LungMap Consortium; Human Cell Atlas Lung Biological NetworkAngiotensin-converting enzyme 2 (ACE2) and accessory proteases (TMPRSS2 and CTSL) are needed for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cellular entry, and their expression may shed light on viral tropism and impact across the body. We assessed the cell-type-specific expression of ACE2, TMPRSS2 and CTSL across 107 single-cell RNA-sequencing studies from different tissues. ACE2, TMPRSS2 and CTSL are coexpressed in specific subsets of respiratory epithelial cells in the nasal passages, airways and alveoli, and in cells from other organs associated with coronavirus disease 2019 (COVID-19) transmission or pathology. We performed a meta-analysis of 31 lung single-cell RNA-sequencing studies with 1,320,896 cells from 377 nasal, airway and lung parenchyma samples from 228 individuals. This revealed cell-type-specific associations of age, sex and smoking with expression levels of ACE2, TMPRSS2 and CTSL. Expression of entry factors increased with age and in males, including in airway secretory cells and alveolar type 2 cells. Expression programs shared by ACE2+TMPRSS2+ cells in nasal, lung and gut tissues included genes that may mediate viral entry, key immune functions and epithelial-macrophage cross-talk, such as genes involved in the interleukin-6, interleukin-1, tumor necrosis factor and complement pathways. Cell-type-specific expression patterns may contribute to the pathogenesis of COVID-19, and our work highlights putative molecular pathways for therapeutic intervention.Item Open Access The role of reactive oxygen and nitrogen species in the response of airway epithelium to particulates.(Environ Health Perspect, 1997-09) Martin, LD; Krunkosky, TM; Dye, JA; Fischer, BM; Jiang, NF; Rochelle, LG; Akley, NJ; Dreher, KL; Adler, KBEpidemiologic and occupational studies indicate adverse health effects due to inhalation of particulate air pollutants, but precise biologic mechanisms responsible have yet to be fully established. The tracheobronchial epithelium forms the body's first physiologic barrier to such airborne pollutants, where ciliary movement functions to remove the offending substances caught in the overlying mucus layer. Resident and infiltrating phagocytic cells also function in this removal process. In this paper, we examine the role of reactive oxygen and nitrogen species (ROS/RNS) in the response of airway epithelium to particulates. Some particulates themselves can generate ROS, as can the epithelial cells, in response to appropriate stimulation. In addition, resident macrophages in the airways and the alveolar spaces can release ROS/RNS after phagocytosis of inhaled particles. These macrophages also release large amounts of tumor necrosis factor alpha (TNF-alpha), a cytokine that can generate responses within the airway epithelium dependent upon intracellular generation of ROS/RNS. As a result, signal transduction pathways are set in motion that may contribute to inflammation and other pathobiology in the airway. Such effects include increased expression of intercellular adhesion molecule 1, interleukin-6, cytosolic and inducible nitric oxide synthase, manganese superoxide dismutase, cytosolic phospholipase A2, and hypersecretion of mucus. Ultimately, ROS/RNS may play a role in the global response of the airway epithelium to particulate pollutants via activation of kinases and transcription factors common to many response genes. Thus, defense mechanisms involved in responding to offending particulates may result in a complex cascade of events that can contribute to airway pathology.Item Open Access Type III Interferons in Antiviral Defenses at Barrier Surfaces.(Trends in immunology, 2018-10) Wells, Alexandra I; Coyne, Carolyn BBarrier surfaces such as the epithelium lining the respiratory and gastrointestinal (GI) tracts, the endothelium comprising the blood-brain barrier (BBB), and placental trophoblasts provide key physical and immunological protection against viruses. These barriers utilize nonredundant mechanisms to suppress viral infections including the production of interferons (IFNs), which induce a strong antiviral state following receptor binding. However, whereas type I IFNs control infection systemically, type III IFNs (IFN-λs) control infection locally at barrier surfaces and are often preferentially induced by these cells. In this review we focus on the role of IFN-λ at barrier surfaces, focusing on the respiratory and GI tracts, the BBB, and the placenta, and on how these IFNs act to suppress viral infections.