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Chen Y, Song W, Zhang H, Ji X. MICALL2 participates in the regulation of epithelial-mesenchymal transition in alveolar epithelial cells - Potential roles in pulmonary fibrosis. Arch Biochem Biophys 2023; 747:109730. [PMID: 37690696 DOI: 10.1016/j.abb.2023.109730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Revised: 08/10/2023] [Accepted: 08/23/2023] [Indexed: 09/12/2023]
Abstract
Epithelial-mesenchymal transition (EMT) of alveolar epithelial cells is a vital process in idiopathic pulmonary fibrosis (IPF), which results in the accumulation of fibroblasts and myofibroblasts and excessive extracellular matrix deposition. Based on RNA sequencing analysis and GEO dataset reanalysis, we screened out MICALL2, a gene upregulated in the lungs of IPF mice and alveolar epithelial type II (ATII) cells from IPF patients, and aimed to explore its role in IPF. We validated the expression of MICALL2 in bleomycin (BLM)-induced IPF mice and TGF-β1-stimulated ATII cells (primary murine ATII cells and A549 cells), and explored the role of MICALL2 in IPF by knockdown of MICALL2 in BLM-induced mice and TGF-β1-stimulated ATII cells. We found that MICALL2 was upregulated in the lungs of BLM-induced mice and TGF-β1-stimulated ATII cells. MICALL2-deficient mice had reduced fibrogenesis and restrained EMT upon BLM challenge. Knockdown of MICALL2 restrained the EMT process, in vitro, through impeding β-catenin nuclear translocation. Mechanistically, we demonstrated that NPAS2 is directly bound to the promoter of MICALL2. Altogether, our data revealed transactivation of MICALL2 induced by NPAS2, contributing to activation of the Wnt/β-catenin pathway in ATII cells, thus leading to the EMT process and subsequent pulmonary fibrosis. Interfering with MICALL2 may represent an innovative therapeutic target to mitigate the extent of IPF.
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Affiliation(s)
- Yingying Chen
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Shenyang, 110022, China
| | - Wei Song
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Shenyang, 110022, China
| | - He Zhang
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Shenyang, 110022, China
| | - Xinping Ji
- Department of Pulmonary and Critical Care Medicine, Shengjing Hospital of China Medical University, Shenyang, 110022, China.
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2
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Ortega FG, Rio C, Jahn A, Gayá A, Calvo J, Monjo M, Montes-Worboys A, Molina-Molina M, Sala-Llinas E, Ramis JM. Antifibrotic Effects of Extracellular Vesicles From Umbilical Cord-Mesenchymal Stem Cells on Lung Myofibroblast Cells. Arch Bronconeumol 2023:S0300-2896(23)00020-0. [PMID: 36822880 DOI: 10.1016/j.arbres.2023.01.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 01/06/2023] [Accepted: 01/30/2023] [Indexed: 02/07/2023]
Affiliation(s)
- Francisco G Ortega
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain; Cell Therapy and Tissue Engineering Group, Research Institute on Health Sciences (IUNICS), Ctra. Valldemossa km 7.5, 07122 Palma, Spain; IBS Granada, Instituto de Investigación Biosanitaria de Granada, 18012 Granada, Spain; Unidad de Gestión Clínica Cartuja, Distrito Sanitario Granada-Metropolitano, 18013 Granada, Spain
| | - Carlos Rio
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
| | - Andreas Jahn
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain
| | - Antonio Gayá
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain; Fundació Banc de Sang i Teixits de les Illes Balears (FBSTIB), 07004 Palma, Spain
| | - Javier Calvo
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain; Fundació Banc de Sang i Teixits de les Illes Balears (FBSTIB), 07004 Palma, Spain
| | - Marta Monjo
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain; Cell Therapy and Tissue Engineering Group, Research Institute on Health Sciences (IUNICS), Ctra. Valldemossa km 7.5, 07122 Palma, Spain; Department of Fundamental Biology and Health Sciences, University of the Balearic Islands (UIB), Ctra. Valldemossa km 7.5, 07122 Palma, Spain.
| | - Ana Montes-Worboys
- ILD Unit, Respiratory Department, University Hospital of Bellvitge, Pneumology Research Group, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Maria Molina-Molina
- ILD Unit, Respiratory Department, University Hospital of Bellvitge, Pneumology Research Group, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain
| | - Ernest Sala-Llinas
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain; ILD Unit, Respiratory Department, University Hospital of Bellvitge, Pneumology Research Group, IDIBELL, L'Hospitalet de Llobregat, Barcelona, Spain; Centro de Investigación en Red de Enfermedades Respiratorias (CIBERES), 28029 Madrid, Spain; Respiratory Department, Hospital Universitari Son Espases, 07010 Palma de Mallorca, Spain
| | - Joana M Ramis
- Health Research Institute of the Balearic Islands (IdISBa), Palma, Spain; Cell Therapy and Tissue Engineering Group, Research Institute on Health Sciences (IUNICS), Ctra. Valldemossa km 7.5, 07122 Palma, Spain; Department of Fundamental Biology and Health Sciences, University of the Balearic Islands (UIB), Ctra. Valldemossa km 7.5, 07122 Palma, Spain.
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3
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Davis-Hall D, Thomas E, Peña B, Magin CM. 3D-bioprinted, phototunable hydrogel models for studying adventitial fibroblast activation in pulmonary arterial hypertension. Biofabrication 2022; 15:10.1088/1758-5090/aca8cf. [PMID: 36533728 PMCID: PMC9933849 DOI: 10.1088/1758-5090/aca8cf] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 12/05/2022] [Indexed: 12/10/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a progressive disease of the lung vasculature, characterized by elevated pulmonary blood pressure, remodeling of the pulmonary arteries, and ultimately right ventricular failure. Therapeutic interventions for PAH are limited in part by the lack ofin vitroscreening platforms that accurately reproduce dynamic arterial wall mechanical properties. Here we present a 3D-bioprinted model of the pulmonary arterial adventitia comprised of a phototunable poly(ethylene glycol) alpha methacrylate (PEG-αMA)-based hydrogel and primary human pulmonary artery adventitia fibroblasts (HPAAFs). This unique biomaterial emulates PAH pathogenesisin vitrothrough a two-step polymerization reaction. First, PEG-αMA macromer was crosslinked off-stoichiometry by 3D bioprinting an acidic bioink solution into a basic gelatin support bath initiating a base-catalyzed thiol-ene reaction with synthetic and biodegradable crosslinkers. Then, matrix stiffening was induced by photoinitiated homopolymerization of unreacted αMA end groups. A design of experiments approach produced a hydrogel platform that exhibited an initial elastic modulus (E) within the range of healthy pulmonary arterial tissue (E= 4.7 ± 0.09 kPa) that was stiffened to the pathologic range of hypertensive tissue (E= 12.8 ± 0.47 kPa) and supported cellular proliferation over time. A higher percentage of HPAAFs cultured in stiffened hydrogels expressed the fibrotic marker alpha-smooth muscle actin than cells in soft hydrogels (88 ± 2% versus 65 ± 4%). Likewise, a greater percentage of HPAAFs were positive for the proliferation marker 5-ethynyl-2'-deoxyuridine (EdU) in stiffened models (66 ± 6%) compared to soft (39 ± 6%). These results demonstrate that 3D-bioprinted, phototunable models of pulmonary artery adventitia are a tool that enable investigation of fibrotic pathogenesisin vitro.
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Affiliation(s)
- Duncan Davis-Hall
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States of America
| | - Emily Thomas
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, United States of America
| | - Brisa Peña
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States of America
- CU-Cardiovascular Institute, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
| | - Chelsea M Magin
- Department of Bioengineering, University of Colorado Denver | Anschutz Medical Campus, Aurora, CO, United States of America
- Department of Pediatrics, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO, United States of America
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4
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Corteselli E, Aboushousha R, Janssen-Heininger Y. S-Glutathionylation-Controlled Apoptosis of Lung Epithelial Cells; Potential Implications for Lung Fibrosis. Antioxidants (Basel) 2022; 11:antiox11091789. [PMID: 36139863 PMCID: PMC9495907 DOI: 10.3390/antiox11091789] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/31/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
Glutathione (GSH), a major antioxidant in mammalian cells, regulates several vital cellular processes, such as nutrient metabolism, protein synthesis, and immune responses. In addition to its role in antioxidant defense, GSH controls biological processes through its conjugation to reactive protein cysteines in a post-translational modification known as protein S-glutathionylation (PSSG). PSSG has recently been implicated in the pathogenesis of multiple diseases including idiopathic pulmonary fibrosis (IPF). Hallmarks of IPF include repeated injury to the alveolar epithelium with aberrant tissue repair, epithelial cell apoptosis and fibroblast resistance to apoptosis, and the accumulation of extracellular matrix and distortion of normal lung architecture. Several studies have linked oxidative stress and PSSG to the development and progression of IPF. Additionally, it has been suggested that the loss of epithelial cell homeostasis and increased apoptosis, accompanied by the release of various metabolites, creates a vicious cycle that aggravates disease progression. In this short review, we highlight some recent studies that link PSSG to epithelial cell apoptosis and highlight the potential implication of metabolites secreted by apoptotic cells.
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5
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Nicholas TP, Boyes WK, Scoville DK, Workman TW, Kavanagh TJ, Altemeier WA, Faustman EM. The effects of gene × environment interactions on silver nanoparticle toxicity in the respiratory system: An adverse outcome pathway. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2021; 13:e1708. [PMID: 33768701 DOI: 10.1002/wnan.1708] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 01/07/2021] [Accepted: 01/30/2021] [Indexed: 11/07/2022]
Abstract
The Adverse Outcome Pathway (AOP) framework is serving as a basis to integrate new data streams in order to enhance the power of predictive toxicology. AOP development for engineered nanomaterials (ENM), including silver nanoparticles (AgNP), is currently lagging behind other chemicals of regulatory interest due to our limited understanding of the mechanism by which underlying genetics or diseases directly modify host response to AgNP exposures. This also highlights the importance of considering the Aggregate Exposure Pathway (AEP) framework, which precedes the AOP framework and outlines source to target site exposure. The AEP and AOP frameworks interface at the target site, where a molecular initiating event (MIE) occurs and is followed by key events (KE) for adverse cellular and organ responses along a biological pathway and ends with the adverse organism response. The primary goal of this study is to use AgNP to interrogate the AEP-AOP framework by organizing and integrating in vitro dose-response data and in vivo exposure-response data from previous studies to evaluate the effects of interactions between host genetic and acquired factors, or gene × environment interactions (G × E), on AgNP toxicity in the respiratory system. Using this framework will help us to identify plausible key event relationships (KER) between MIE and adverse organism responses when KE are not measured using the same assay in order to derive future predictive models, guide research, and support development of tools for making risk-based, regulatory decisions on ENM. This article is categorized under: Toxicology and Regulatory Issues in Nanomedicine > Toxicology of Nanomaterials Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine.
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Affiliation(s)
- Tyler P Nicholas
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington, USA
| | - William K Boyes
- Center for Public Health and Environmental Assessment, Office of Research and Development, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina, USA
| | - David K Scoville
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Tomomi W Workman
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington, USA
| | - William A Altemeier
- Department of Medicine, Division of Pulmonary, Critical Care, and Sleep Medicine, University of Washington, Seattle, Washington, USA
| | - Elaine M Faustman
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, USA
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6
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Wicher SA, Roos BB, Teske JJ, Fang YH, Pabelick C, Prakash YS. Aging increases senescence, calcium signaling, and extracellular matrix deposition in human airway smooth muscle. PLoS One 2021; 16:e0254710. [PMID: 34324543 PMCID: PMC8321097 DOI: 10.1371/journal.pone.0254710] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Accepted: 07/01/2021] [Indexed: 12/23/2022] Open
Abstract
Lung function declines as people age and their lungs become stiffer. With an increasing elderly population, understanding mechanisms that contribute to these structural and functional changes in the aging lung is important. Part of the aging process is characterized by thicker, more fibrotic airways, and senile emphysema caused by changes in lung parenchyma. There is also senescence, which occurs throughout the body with aging. Here, using human airway smooth muscle (ASM) cells from patients in different age groups, we explored senescence pathways and changes in intracellular calcium signaling and extracellular matrix (ECM) deposition to elucidate potential mechanisms by which aging leads to thicker and stiffer lungs. Senescent markers p21, γH2AX, and β-gal, and some senescence-associated secretory proteins (SASP) increased with aging, as shown by staining and biochemical analyses. Agonist-induced intracellular Ca2+ responses, measured using fura-2 loaded cells and fluorescence imaging, increased with age. However, biochemical analysis showed that expression of the following markers decreased with age: M3 muscarinic receptor, TRPC3, Orai1, STIM1, SERCA2, MMP2 and MMP9. In contrast, collagen III, and fibronectin deposition increased with age. These data show that senescence increases in the aging airways that is associated with a stiffer but surprisingly greater intracellular calcium signaling as a marker for contractility. ASM senescence may enhance fibrosis in a feed forward loop promoting remodeling and altered calcium storage and buffering.
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Affiliation(s)
- Sarah A. Wicher
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Benjamin B. Roos
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Jacob J. Teske
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States of America
| | - Yun Hua Fang
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States of America
| | - Christina Pabelick
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States of America
| | - Y. S. Prakash
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, MN, United States of America
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, MN, United States of America
- * E-mail:
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7
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Ji R, Zhu XJ, Wang ZR, Huang LQ. Cortactin in Epithelial-Mesenchymal Transition. Front Cell Dev Biol 2020; 8:585619. [PMID: 33195233 PMCID: PMC7606982 DOI: 10.3389/fcell.2020.585619] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 09/24/2020] [Indexed: 12/15/2022] Open
Abstract
Cortactin, a member of the actin-binding protein family, plays an important role in cell movement involving the cytoskeleton, as cell movement mediated by cortactin may induce the epithelial–mesenchymal transition. Cortactin participates in tumor proliferation, migration, and invasion and other related disease processes by binding to different proteins and participating in different pathways and mechanisms that induce the occurrence of these disease processes. Therefore, this article reviews the correlations between cortactin, the actin cytoskeleton, and the epithelial–mesenchymal transition and discusses its clinical importance in tumor therapy.
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Affiliation(s)
- Rong Ji
- Zhangjiagang TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Jiangsu, China
| | - Xiao-Juan Zhu
- Zhangjiagang TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Jiangsu, China
| | - Zhi-Rong Wang
- Zhangjiagang TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Jiangsu, China
| | - Li-Qiang Huang
- Zhangjiagang TCM Hospital Affiliated to Nanjing University of Chinese Medicine, Jiangsu, China
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8
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Petrou CL, D'Ovidio TJ, Bölükbas DA, Tas S, Brown RD, Allawzi A, Lindstedt S, Nozik-Grayck E, Stenmark KR, Wagner DE, Magin CM. Clickable decellularized extracellular matrix as a new tool for building hybrid-hydrogels to model chronic fibrotic diseases in vitro. J Mater Chem B 2020; 8:6814-6826. [PMID: 32343292 PMCID: PMC9020195 DOI: 10.1039/d0tb00613k] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fibrotic disorders account for over one third of mortalities worldwide. Despite great efforts to study the cellular and molecular processes underlying fibrosis, there are currently few effective therapies. Dual-stage polymerization reactions are an innovative tool for recreating heterogeneous increases in extracellular matrix (ECM) modulus, a hallmark of fibrotic diseases in vivo. Here, we present a clickable decellularized ECM (dECM) crosslinker incorporated into a dynamically responsive poly(ethylene glycol)-α-methacrylate (PEGαMA) hybrid-hydrogel to recreate ECM remodeling in vitro. An off-stoichiometry thiol-ene Michael addition between PEGαMA (8-arm, 10 kg mol-1) and the clickable dECM resulted in hydrogels with an elastic modulus of E = 3.6 ± 0.24 kPa, approximating healthy lung tissue (1-5 kPa). Next, residual αMA groups were reacted via a photo-initiated homopolymerization to increase modulus values to fibrotic levels (E = 13.4 ± 0.82 kPa) in situ. Hydrogels with increased elastic moduli, mimicking fibrotic ECM, induced a significant increase in the expression of myofibroblast transgenes. The proportion of primary fibroblasts from dual-reporter mouse lungs expressing collagen 1a1 and alpha-smooth muscle actin increased by approximately 60% when cultured on stiff and dynamically stiffened hybrid-hydrogels compared to soft. Likewise, fibroblasts expressed significantly increased levels of the collagen 1a1 transgene on stiff regions of spatially patterned hybrid-hydrogels compared to the soft areas. Collectively, these results indicate that hybrid-hydrogels are a new tool that can be implemented to spatiotemporally induce a phenotypic transition in primary murine fibroblasts in vitro.
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Affiliation(s)
- Cassandra L Petrou
- Department of Bioengineering, University of Colorado, Anschutz Medical Campus, 12700 E 19th Ave MS C272 Aurora, Denver, CO 80045, USA
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9
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Li X, Wong SS, Tan C, Espinoza CR, Hagood JS. Loss of Thy-1 may reduce lung regeneration after pneumonectomy in mice. Minerva Med 2020; 112:622-630. [PMID: 32696636 DOI: 10.23736/s0026-4806.20.06691-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND Lung regeneration plays an important role in lung repair after injury. It is reliant upon proliferation of multiple cell types in the lung, including endothelium, epithelium, and fibroblasts, as well as remodeling of the extracellular matrix. METHODS Lung regeneration following injury progresses via an initial infammatory response during which macrophages clear the tissue of cellular debris. This process continues through cellular proliferation when existing cells and progenitors act to repopulate cells lost during injury, followed by tissue maturation in which newly formed cells achieve a diferentiated phenotype. RESULTS Signaling pathways critical for lung regeneration include FGF, EGF, WNT, and NOTCH. In addition, HDACs, miRNAs, ELASTIN, and MMP14 have been shown to regulate lung regeneration. Partial pneumonectomy (PNX) has been used as a therapeutic and investigational tool for several decades. Following PNX the remaining lung increases in size to compensate for loss of volume and respiratory capacity. CONCLUSIONS Much has been learned about the triggers and mechanisms regulating pulmonary regeneration. However, the role of thymocyte differentiation antigen-1(thy-1) in post-PNX lung growth remains incompletely characterized. Thy-1 is a phosphatidylinositol glycoprotein with a relative molecular weight of 25000~37000 Da, which is expressed in almost all types of fibroblasts and regulates many biological functions. It not only supports the structure of fibroblasts, but also can balance cell proliferation, migration and regulate the synthesis of immune inflammatory mediators.
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Affiliation(s)
- Xiaoping Li
- Department of Thoracic Surgery, Tianjin First Central Hospital, Tianjin, China.,Department of Paediatrics, University of California San Diego, CA, USA
| | - Simon S Wong
- Department of Paediatrics, University of California San Diego, CA, USA
| | - Chunting Tan
- Department of Paediatrics, University of California San Diego, CA, USA
| | - Celia R Espinoza
- Department of Paediatrics, University of California San Diego, CA, USA
| | - James S Hagood
- Department of Pediatric Pulmonology, University of North Carolina, Chapel Hill, NC, USA -
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10
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Nicholas TP, Haick AK, Workman TW, Griffith WC, Nolin JD, Kavanagh TJ, Faustman EM, Altemeier WA. The effects of genotype × phenotype interactions on silver nanoparticle toxicity in organotypic cultures of murine tracheal epithelial cells. Nanotoxicology 2020; 14:908-928. [PMID: 32574512 DOI: 10.1080/17435390.2020.1777475] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Silver nanoparticles (AgNP) are used in multiple applications but primarily in the manufacturing of antimicrobial products. Previous studies have identified AgNP toxicity in airway epithelial cells, but no in vitro studies to date have used organotypic cultures as a high-content in vitro model of the conducting airway to characterize the effects of interactions between host genetic and acquired factors, or gene × phenotype interactions (G × P), on AgNP toxicity. In the present study, we derived organotypic cultures from primary murine tracheal epithelial cells (MTEC) to characterize nominal and dosimetric dose-response relationships for AgNPs with a gold core on barrier dysfunction, glutathione (GSH) depletion, reactive oxygen species (ROS) production, lipid peroxidation, and cytotoxicity across two genotypes (A/J and C57BL/6J mice), two phenotypes ('Normal' and 'Type 2 [T2]-Skewed'), and two exposures (an acute exposure of 24 h and a subacute exposure of 4 h, every other day, over 5 days [5 × 4 h]). We characterized the 'T2-Skewed' phenotype as an in vitro model of chronic respiratory diseases, which was marked by increased sensitivity to AgNP-induced barrier dysfunction, GSH depletion, ROS production, lipid peroxidation, and cytotoxicity, suggesting that asthmatics are a sensitive population to AgNP exposures in occupational settings. This also suggests that exposure limits, which should be based upon the most sensitive population, should be derived using in vitro and in vivo models of chronic respiratory diseases. This study highlights the importance of considering dosimetry as well as G × P effects when screening and prioritizing potential respiratory toxicants. Such in vitro studies can be used to inform regulatory policy aimed at special protections for all populations.
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Affiliation(s)
- Tyler P Nicholas
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.,Center for Lung Biology, University of Washington, Seattle, WA, USA
| | - Anoria K Haick
- Vaccine and Infectious Disease Division, Fred Hutchinson Cancer Research Center, Seattle, WA, USA
| | - Tomomi W Workman
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - William C Griffith
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - James D Nolin
- Center for Lung Biology, University of Washington, Seattle, WA, USA
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA.,Center for Lung Biology, University of Washington, Seattle, WA, USA
| | - Elaine M Faustman
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, WA, USA
| | - William A Altemeier
- Center for Lung Biology, University of Washington, Seattle, WA, USA.,Department of Medicine, University of Washington, Seattle, WA, USA
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11
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Parimon T, Yao C, Stripp BR, Noble PW, Chen P. Alveolar Epithelial Type II Cells as Drivers of Lung Fibrosis in Idiopathic Pulmonary Fibrosis. Int J Mol Sci 2020; 21:E2269. [PMID: 32218238 PMCID: PMC7177323 DOI: 10.3390/ijms21072269] [Citation(s) in RCA: 181] [Impact Index Per Article: 45.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/15/2020] [Accepted: 03/19/2020] [Indexed: 12/19/2022] Open
Abstract
: Alveolar epithelial type II cells (AT2) are a heterogeneous population that have critical secretory and regenerative roles in the alveolus to maintain lung homeostasis. However, impairment to their normal functional capacity and development of a pro-fibrotic phenotype has been demonstrated to contribute to the development of idiopathic pulmonary fibrosis (IPF). A number of factors contribute to AT2 death and dysfunction. As a mucosal surface, AT2 cells are exposed to environmental stresses that can have lasting effects that contribute to fibrogenesis. Genetical risks have also been identified that can cause AT2 impairment and the development of lung fibrosis. Furthermore, aging is a final factor that adds to the pathogenic changes in AT2 cells. Here, we will discuss the homeostatic role of AT2 cells and the studies that have recently defined the heterogeneity of this population of cells. Furthermore, we will review the mechanisms of AT2 death and dysfunction in the context of lung fibrosis.
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Affiliation(s)
- Tanyalak Parimon
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Women’s Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Changfu Yao
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Women’s Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Barry R Stripp
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Women’s Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Paul W Noble
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Women’s Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
| | - Peter Chen
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Women’s Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA 90048, USA
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12
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van der Velden JL, Alcorn JF, Chapman DG, Lundblad LKA, Irvin CG, Davis RJ, Butnor K, Janssen-Heininger YMW. Airway epithelial specific deletion of Jun-N-terminal kinase 1 attenuates pulmonary fibrosis in two independent mouse models. PLoS One 2020; 15:e0226904. [PMID: 31935227 PMCID: PMC6959564 DOI: 10.1371/journal.pone.0226904] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 12/07/2019] [Indexed: 01/06/2023] Open
Abstract
The stress-induced kinase, c-Jun-N-terminal kinase 1 (JNK1) has previously been implicated in the pathogenesis of lung fibrosis. However, the exact cell type(s) wherein JNK1 exerts its pro-fibrotic role(s) remained enigmatic. Herein we demonstrate prominent activation of JNK in bronchial epithelia using the mouse models of bleomycin- or AdTGFβ1-induced fibrosis. Furthermore, in lung tissues of patients with idiopathic pulmonary fibrosis (IPF), active JNK was observed in various regions including type I and type II pneumocytes and fibroblasts. No JNK activity was observed in adjacent normal tissue or in normal control tissue. To address the role of epithelial JNK1, we ablated Jnk1 form bronchiolar and alveolar type II epithelial cells using CCSP-directed Cre recombinase-mediated ablation of LoxP-flanked Jnk1 alleles. Our results demonstrate that ablation of Jnk1 from airway epithelia resulted in a strong protection from bleomycin- or adenovirus expressing active transforming growth factor beta-1 (AdTGFβ1)-induced fibrosis. Ablation of the Jnk1 allele at a time when collagen increases were already present showed a reversal of existing increases in collagen content. Epithelial Jnk1 ablation resulted in attenuation of mesenchymal genes and proteins in lung tissue and preserved expression of epithelial genes. Collectively, these data suggest that epithelial JNK1 contributes to the pathogenesis of pulmonary fibrosis. Given the presence of active JNK in lungs from patients with IPF, targeting JNK1 in airway epithelia may represent a potential treatment strategy to combat this devastating disease.
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Affiliation(s)
- Jos L. van der Velden
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont, United States of America
| | - John F. Alcorn
- Children’s Hospital of Pittsburgh University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania, United States of America
| | - David G. Chapman
- Departments of Medicine, University of Vermont, Burlington, Vermont, United States of America
| | - Lennart K. A. Lundblad
- Departments of Medicine, University of Vermont, Burlington, Vermont, United States of America
| | - Charles G. Irvin
- Departments of Medicine, University of Vermont, Burlington, Vermont, United States of America
| | - Roger J. Davis
- Howard Hughes Medical Institute, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Kelly Butnor
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont, United States of America
| | - Yvonne M. W. Janssen-Heininger
- Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, Vermont, United States of America
- * E-mail:
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13
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Parimon T, Yao C, Habiel DM, Ge L, Bora SA, Brauer R, Evans CM, Xie T, Alonso-Valenteen F, Medina-Kauwe LK, Jiang D, Noble PW, Hogaboam CM, Deng N, Burgy O, Antes TJ, Königshoff M, Stripp BR, Gharib SA, Chen P. Syndecan-1 promotes lung fibrosis by regulating epithelial reprogramming through extracellular vesicles. JCI Insight 2019; 5:129359. [PMID: 31393853 PMCID: PMC6777916 DOI: 10.1172/jci.insight.129359] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 08/01/2019] [Indexed: 12/13/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic and fatal lung disease. A maladaptive epithelium due to chronic injury is a prominent feature and contributor to pathogenic cellular communication in IPF. Recent data highlight the concept of a "reprogrammed" lung epithelium as critical in the development of lung fibrosis. Extracellular vesicles (EVs) are potent mediator of cellular crosstalk, and recent evidence supports their role in lung pathologies such as IPF. Here, we demonstrate that syndecan-1 is overexpressed by the epithelium in the lungs of IPF patients and in murine models after bleomycin injury. Moreover, we find that syndecan-1 is a pro-fibrotic signal that alters alveolar type II (ATII) cell phenotypes by augmenting TGFβ and Wnt signaling among other pro-fibrotic pathways. Importantly, we demonstrate that syndecan-1 controls the packaging of several anti-fibrotic microRNAs into EVs that have broad effects over several fibrogenic signaling networks as a mechanism of regulating epithelial plasticity and pulmonary fibrosis. Collectively, our work reveals new insight into how EVs orchestrate cellular signals that promote lung fibrosis and demonstrate the importance of syndecan-1 in coordinating these programs.
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Affiliation(s)
- Tanyalak Parimon
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Changfu Yao
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - David M. Habiel
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Lingyin Ge
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Stephanie A. Bora
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Rena Brauer
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Christopher M. Evans
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Ting Xie
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | | | | | - Dianhua Jiang
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Paul W. Noble
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Biomedical Sciences
| | - Cory M. Hogaboam
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Biomedical Sciences
| | - Nan Deng
- Samuel Oschin Comprehensive Cancer Institute, and
| | - Olivier Burgy
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Travis J. Antes
- Smidt Heart Institute, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Melanie Königshoff
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Barry R. Stripp
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Biomedical Sciences
| | - Sina A. Gharib
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Peter Chen
- Women’s Guild Lung Institute, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Cedars-Sinai Medical Center, Los Angeles, California, USA
- Department of Biomedical Sciences
- Samuel Oschin Comprehensive Cancer Institute, and
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14
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Nicholas TP, Kavanagh TJ, Faustman EM, Altemeier WA. The Effects of Gene × Environment Interactions on Silver Nanoparticle Toxicity in the Respiratory System. Chem Res Toxicol 2019; 32:952-968. [PMID: 31124663 DOI: 10.1021/acs.chemrestox.8b00234] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Silver nanoparticles (AgNP) are used in multiple applications but primarily in the manufacturing of antimicrobial products. AgNP toxicity in the respiratory system is well characterized, but few in vitro or in vivo studies have evaluated the effects of interactions between host genetic and acquired factors or gene × environment interactions (G × E) on AgNP toxicity in the respiratory system. The primary goal of this article is to review host genetic and acquired factors identified across in vitro and in vivo studies and prioritize those necessary for defining exposure limits to protect all populations. The impact of these exposures and the work being done to address the current limited protections are also discussed. Future research on G × E effects on AgNP toxicity is warranted and will assist with informing regulatory or recommended exposure limits that enforce special protections for all populations to AgNP exposures in occupational settings.
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Affiliation(s)
- Tyler P Nicholas
- Department of Environmental and Occupational Health Sciences , University of Washington , Seattle , Washington 98109 , United States
| | - Terrance J Kavanagh
- Department of Environmental and Occupational Health Sciences , University of Washington , Seattle , Washington 98109 , United States
| | - Elaine M Faustman
- Department of Environmental and Occupational Health Sciences , University of Washington , Seattle , Washington 98109 , United States
| | - William A Altemeier
- Department of Medicine, Division of Pulmonary, Critical Care and Sleep Medicine , University of Washington , Seattle , Washington 98109 , United States
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15
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Neveu WA, Staitieh BS, Mills ST, Guidot DM, Sueblinvong V. Alcohol-Induced Interleukin-17 Expression Causes Murine Lung Fibroblast-to-Myofibroblast Transdifferentiation via Thy-1 Down-Regulation. Alcohol Clin Exp Res 2019; 43:1427-1438. [PMID: 31081931 DOI: 10.1111/acer.14110] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2018] [Accepted: 05/06/2019] [Indexed: 12/11/2022]
Abstract
BACKGROUND Alcohol exposure induces TGFβ1 and renders the lung susceptible to injury and disrepair. We determined that TGFβ1 regulates myofibroblast differentiation through the loss of Thy-1 expression and consequent induction of α-SMA. TGFβ1 is important for T helper 17 (Th17) differentiation and IL-17 secretion, which in turn participates in tissue repair. We hypothesized that alcohol induces Th17 differentiation via TGFβ1 and that IL-17 produced by these cells contributes to the development of profibrotic lung myofibroblasts. METHODS Primary lung fibroblasts (PLFs) were treated with alcohol, TGFβ1, and IL-17 and then analyzed for Thy-1 expression and cell morphology. Naïve and Th17-polarized CD4+ T cells were exposed to alcohol and assessed for IL-17 expression. CD4+ T cells from alcohol-fed mice were analyzed for Th17 and IL-17 expression. Lungs of control-fed, bleomycin-treated and alcohol-fed, bleomycin-treated mice were analyzed for IL-17 protein expression. RESULTS Alcohol-treated PLFs expressed lower levels of Thy-1 than untreated cells. TGFβ1 or IL-17 exposure suppressed PLF Thy-1 expression. When administered together, TGFβ1 and IL-17 additively down-regulated Thy-1 expression. Exposure of naïve and Th17-polarized CD4+ T cells to alcohol induced the Th17 phenotype and augmented their production of IL-17. CD4+ Th17+ levels are elevated in the peripheral compartment but not in the lungs of alcohol-fed animals. Treatment of the PLFs with IL-17 and alcohol induced α-SMA expression. Induction of α-SMA and myofibroblast morphology by IL-17 occurred selectively in a Thy-1- fibroblast subpopulation. Chronic alcohol ingestion augmented lung-specific IL-17 expression following bleomycin-induced lung injury. CONCLUSIONS Alcohol exposure skews T cells toward a Th17 immune response that in turn primes the lung for fibroproliferative disrepair through loss of Thy-1 expression and induction of myofibroblast differentiation. These effects suggest that IL-17 and TGFβ1 contribute to fibroproliferative disrepair in the lung and targeting these proteins could limit morbidity and mortality following lung injury in alcoholic individuals.
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Affiliation(s)
- Wendy A Neveu
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Bashar S Staitieh
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - Stephen T Mills
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
| | - David M Guidot
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia.,Atlanta VAMC, Decatur, Georgia
| | - Viranuj Sueblinvong
- Division of Pulmonary, Allergy, Critical Care & Sleep Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
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16
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Rana MK, Aloisio FM, Choi C, Barber DL. Formin-dependent TGF-β signaling for epithelial to mesenchymal transition. Mol Biol Cell 2018; 29:1465-1475. [PMID: 29668357 PMCID: PMC6014098 DOI: 10.1091/mbc.e17-05-0325] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
The role of distinct actin filament architectures in epithelial plasticity remains incompletely understood. We therefore determined roles for formins and the Arp2/3 complex, which are actin nucleators generating unbranched and branched actin filaments, respectively, in the process of epithelial to mesenchymal transition (EMT). In clonal lung, mammary, and renal epithelial cells, the formin activity inhibitor SMIFH2 but not the Arp2/3 complex activity inhibitor CK666 blocked EMT induced by TGF-β. SMIFH2 prevented the proximal signal of increased Smad2 phosphorylation and hence also blocked downstream EMT markers, including actin filament remodeling, decreased expression of the adherens junction protein E-cadherin, and increased expression of the matrix protein fibronectin and the transcription factor Snail. The short hairpin RNA silencing of formins DIAPH1 and DIAPH3 but not other formins phenocopied SMIFH2 effects and inhibited Smad2 phosphorylation and changes in Snail and cadherin expression. Formin activity was not necessary for the cell surface expression or dimerization of TGF-β receptors, or for nuclear translocation of TAZ, a transcription cofactor in Hippo signaling also regulated by TGF-β. Our findings reveal a previously unrecognized role for formin-dependent actin architectures in proximal TGF-β signaling that is necessary for Smad2 phosphorylation but not for cross-talk to TAZ.
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Affiliation(s)
- Manish K Rana
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
| | - Francesca M Aloisio
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
| | - Changhoon Choi
- Department of Radiation Oncology, Samsung Medical Center, Seoul 06351, South Korea
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, San Francisco, CA 94143
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17
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Abstract
PURPOSE OF REVIEW The pathogenesis of lung cancer and pulmonary fibrotic disorders partially overlaps. This review focuses on the common features of the two disease categories, aimed at advancing our translational understanding of their pathobiology and at fostering the development of new therapies. RECENT FINDINGS Both malignant and collagen-producing lung cells display enhanced cellular proliferation, increased resistance to apoptosis, a propensity for invading and distorting the lung parenchyma, as well as stemness potential. These characteristics are reinforced by the tissue microenvironment and inflammation seems to play an important adjuvant role in both types of disorders. SUMMARY Unraveling the thread of the common and distinct characteristics of lung fibrosis and cancer might contribute to a more comprehensive approach of the pathobiology of both diseases and to a pathfinder for novel and personalized therapeutic strategies.
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18
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Weibel ER. Lung morphometry: the link between structure and function. Cell Tissue Res 2016; 367:413-426. [PMID: 27981379 DOI: 10.1007/s00441-016-2541-4] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2016] [Accepted: 11/18/2016] [Indexed: 10/20/2022]
Abstract
The study of the structural basis of gas exchange function in the lung depends on the availability of quantitative information that concerns the structures establishing contact between the air in the alveoli and the blood in the alveolar capillaries, which can be entered into physiological equations for predicting oxygen uptake. This information is provided by morphometric studies involving stereological methods and allows estimates of the pulmonary diffusing capacity of the human lung that agree, in experimental studies, with the maximal oxygen consumption. The basis for this "machine lung" structure lies in the complex design of the cells building an extensive air-blood barrier with minimal cell mass.
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Affiliation(s)
- Ewald R Weibel
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, CH-3000, Bern 9, Switzerland.
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19
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Barron L, Gharib SA, Duffield JS. Lung Pericytes and Resident Fibroblasts: Busy Multitaskers. THE AMERICAN JOURNAL OF PATHOLOGY 2016; 186:2519-31. [PMID: 27555112 DOI: 10.1016/j.ajpath.2016.07.004] [Citation(s) in RCA: 84] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 06/30/2016] [Accepted: 07/05/2016] [Indexed: 02/06/2023]
Abstract
Pericytes, resident fibroblasts, and mesenchymal stem cells are poorly described cell populations. They have recently been characterized in much greater detail in rodent lungs and have been shown to play important roles in development, homeostasis, response to injury and pathogens, as well as recovery from damage. These closely related mesenchymal cell populations form extensive connections to the lung's internal structure, as well as its internal and external surfaces. They generate and remodel extracellular matrix, coregulate the vasculature, help maintain and restore the epithelium, and act as sentries for the immune system. In this review, we revisit these functions in light of significant advances in characterizing and tracking lung fibroblast populations in rodents. Lineage tracing experiments have mapped the heritage, identified functions that discriminate lung pericytes from resident fibroblasts, identified a subset of mesenchymal stem cells, and shown these populations to be the predominant progenitors of pathological fibroblasts and myofibroblasts in lung diseases. These findings point to the importance of resident lung mesenchymal populations as therapeutic targets in acute lung injury as well as fibrotic and degenerative diseases. Far from being passive and quiescent, pericytes and resident fibroblasts are busily sensing and responding, through diverse mechanisms, to changes in lung health and function.
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Affiliation(s)
- Luke Barron
- Department of Research and Development, Biogen, Cambridge, Massachusetts
| | - Sina A Gharib
- Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, Washington
| | - Jeremy S Duffield
- Department of Research and Development, Biogen, Cambridge, Massachusetts; Division of Pulmonary and Critical Care Medicine, University of Washington, Seattle, Washington.
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20
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Horowitz JC, Osterholzer JJ, Marazioti A, Stathopoulos GT. "Scar-cinoma": viewing the fibrotic lung mesenchymal cell in the context of cancer biology. Eur Respir J 2016; 47:1842-54. [PMID: 27030681 DOI: 10.1183/13993003.01201-2015] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2015] [Accepted: 02/28/2016] [Indexed: 12/22/2022]
Abstract
Lung cancer and pulmonary fibrosis are common, yet distinct, pathological processes that represent urgent unmet medical needs. Striking clinical and mechanistic parallels exist between these distinct disease entities. The goal of this article is to examine lung fibrosis from the perspective of cancer-associated phenotypic hallmarks, to discuss areas of mechanistic overlap and distinction, and to highlight profibrotic mechanisms that contribute to carcinogenesis. Ultimately, we speculate that such comparisons might identify opportunities to leverage our current understanding of the pathobiology of each disease process in order to advance novel therapeutic approaches for both. We anticipate that such "outside the box" concepts could be translated to a more precise and individualised approach to fibrotic diseases of the lung.
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Affiliation(s)
- Jeffrey C Horowitz
- Division of Pulmonary and Critical Care Medicine, Dept of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - John J Osterholzer
- Division of Pulmonary and Critical Care Medicine, Dept of Internal Medicine, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Antonia Marazioti
- Laboratory for Molecular Respiratory Carcinogenesis, Dept of Physiology, Faculty of Medicine, University of Patras, Rio, Greece
| | - Georgios T Stathopoulos
- Laboratory for Molecular Respiratory Carcinogenesis, Dept of Physiology, Faculty of Medicine, University of Patras, Rio, Greece Comprehensive Pneumology Center and Institute for Lung Biology and Disease, University Hospital, Ludwig-Maximilians University and Helmholtz Zentrum München, Member of the German Center for Lung Research (DZL), Munich, Germany
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21
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Lin C, Yao E, Chuang PT. A conserved MST1/2-YAP axis mediates Hippo signaling during lung growth. Dev Biol 2015; 403:101-13. [PMID: 25912685 DOI: 10.1016/j.ydbio.2015.04.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Revised: 03/06/2015] [Accepted: 04/09/2015] [Indexed: 11/29/2022]
Abstract
Hippo signaling is a critical player in controlling the growth of several tissues and organs in diverse species. The current model of Hippo signaling postulates a cascade of kinase activity initiated by the MST1/2 kinases in response to external stimuli. This leads to inactivation of the transcriptional coactivators, YAP/TAZ, due to their cytoplasmic retention and degradation that is correlated with YAP/TAZ phosphorylation. In most tissues examined, YAP plays a more dominant role than TAZ. Whether a conserved Hippo pathway is utilized during lung growth and development is unclear. In particular, the regulatory relationship between MST1/2 and YAP/TAZ in the lung remains controversial. By employing the Shh-Cre mouse line to efficiently inactivate genes in the lung epithelium, we show that loss of MST1/2 kinases in the epithelium can lead to neonatal lethality caused by lung defects. This is manifested by perturbation of lung epithelial cell proliferation and differentiation. These phenotypes are more severe than those produced by Nkx2.1-Cre, highlighting the effects of differential Cre activity on phenotypic outcomes. Importantly, expression of YAP targets is upregulated and the ratio of phospho-YAP to total YAP protein levels is reduced in Mst1/2-deficient lungs, all of which are consistent with a negative role of MST1/2 in controlling YAP function. This model gains further support from both in vivo and in vitro studies. Genetic removal of one allele of Yap or one copy of both Yap and Taz rescues neonatal lethality and lung phenotypes due to loss of Mst1/2. Moreover, knockdown of Yap in lung epithelial cell lines restores diminished alveolar marker expression caused by Mst1/2 inactivation. These results demonstrate that MST1/2 inhibit YAP/TAZ activity and establish a conserved MST1/2-YAP axis in coordinating lung growth during development.
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Affiliation(s)
- Chuwen Lin
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, United States
| | - Erica Yao
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, United States
| | - Pao-Tien Chuang
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, United States.
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22
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Hofer CC, Woods PS, Davis IC. Infection of mice with influenza A/WSN/33 (H1N1) virus alters alveolar type II cell phenotype. Am J Physiol Lung Cell Mol Physiol 2015; 308:L628-38. [PMID: 25595651 DOI: 10.1152/ajplung.00373.2014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 01/12/2015] [Indexed: 11/22/2022] Open
Abstract
Influenza viruses cause acute respiratory disease of great importance to public health. Alveolar type II (ATII) respiratory epithelial cells are central to normal lung function and are a site of influenza A virus replication in the distal lung. However, the consequences of infection for ATII cell function are poorly understood. To determine the impact of influenza infection on ATII cells we used C57BL/6-congenic SP-C(GFP) mice that express green fluorescent protein (GFP) under the control of the surfactant protein-C (SP-C) promoter, which is only active in ATII cells. Most cells isolated from the lungs of uninfected SP-C(GFP) mice were GFP(+) but did not express the alveolar type I (ATI) antigen podoplanin (PODO). ATII cells were also EpCAM(+) and α2,3-linked sialosaccharide(+). Infection with influenza A/WSN/33 virus caused severe hypoxemia and pulmonary edema. This was accompanied by loss of whole lung GFP fluorescence, reduced ATII cell yields, increased ATII cell apoptosis, reduced SP-C gene and protein expression in ATII cell lysates, and increased PODO gene and protein levels. Flow cytometry indicated that infection decreased GFP(+)/PODO(-) cells and increased GFP(-)/PODO(+) and GFP(-)/PODO(-) cells. Very few GFP(+)/PODO(+) cells were detectable. Finally, infection resulted in a significant decline in EpCAM expression by PODO(+) cells, but had limited effects on α2,3-linked sialosaccharides. Our findings indicate that influenza infection results in a progressive differentiation of ATII cells into ATI-like cells, possibly via an SP-C(-)/PODO(-) intermediate, to replace dying or dead ATI cells. However, impaired SP-C synthesis is likely to contribute significantly to reduced lung compliance in infected mice.
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Affiliation(s)
- Christian C Hofer
- Department of Veterinary Preventive Medicine, The Ohio State University, Columbus, Ohio; and
| | - Parker S Woods
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
| | - Ian C Davis
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio
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23
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Jang JH, Bruse S, Huneidi S, Schrader RM, Monick MM, Lin Y, Carter AB, Klingelhutz AJ, Nyunoya T. Acrolein-exposed normal human lung fibroblasts in vitro: cellular senescence, enhanced telomere erosion, and degradation of Werner's syndrome protein. ENVIRONMENTAL HEALTH PERSPECTIVES 2014; 122:955-62. [PMID: 24747221 PMCID: PMC4154210 DOI: 10.1289/ehp.1306911] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 04/15/2014] [Indexed: 05/25/2023]
Abstract
BACKGROUND Acrolein is a ubiquitous environmental hazard to human health. Acrolein has been reported to activate the DNA damage response and induce apoptosis. However, little is known about the effects of acrolein on cellular senescence. OBJECTIVES We examined whether acrolein induces cellular senescence in cultured normal human lung fibroblasts (NHLF). METHODS We cultured NHLF in the presence or absence of acrolein and determined the effects of acrolein on cell proliferative capacity, senescence-associated β-galactosidase activity, the known senescence-inducing pathways (e.g., p53, p21), and telomere length. RESULTS We found that acrolein induced cellular senescence by increasing both p53 and p21. The knockdown of p53 mediated by small interfering RNA (siRNA) attenuated acrolein-induced cellular senescence. Acrolein decreased Werner's syndrome protein (WRN), a member of the RecQ helicase family involved in DNA repair and telomere maintenance. Acrolein-induced down-regulation of WRN protein was rescued by p53 knockdown or proteasome inhibition. Finally, we found that acrolein accelerated p53-mediated telomere shortening. CONCLUSIONS These results suggest that acrolein induces p53-mediated cellular senescence accompanied by enhanced telomere attrition and WRN protein down-regulation.
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Affiliation(s)
- Jun-Ho Jang
- Division of Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, University of New Mexico and New Mexico VA Health Care System, Albuquerque, New Mexico, USA
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24
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Rezaee F, Georas SN. Breaking barriers. New insights into airway epithelial barrier function in health and disease. Am J Respir Cell Mol Biol 2014; 50:857-69. [PMID: 24467704 DOI: 10.1165/rcmb.2013-0541rt] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Epithelial permeability is a hallmark of mucosal inflammation, but the molecular mechanisms involved remain poorly understood. A key component of the epithelial barrier is the apical junctional complex that forms between neighboring cells. Apical junctional complexes are made of tight junctions and adherens junctions and link to the cellular cytoskeleton via numerous adaptor proteins. Although the existence of tight and adherens junctions between epithelial cells has long been recognized, in recent years there have been significant advances in our understanding of the molecular regulation of junctional complex assembly and disassembly. Here we review the current thinking about the structure and function of the apical junctional complex in airway epithelial cells, emphasizing the translational aspects of relevance to cystic fibrosis and asthma. Most work to date has been conducted using cell culture models, but technical advancements in imaging techniques suggest that we are on the verge of important new breakthroughs in this area in physiological models of airway diseases.
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Affiliation(s)
- Fariba Rezaee
- 1 Division of Pediatric Pulmonary Medicine, Department of Pediatrics, and
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25
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Kotton DN, Morrisey EE. Lung regeneration: mechanisms, applications and emerging stem cell populations. Nat Med 2014; 20:822-32. [PMID: 25100528 PMCID: PMC4229034 DOI: 10.1038/nm.3642] [Citation(s) in RCA: 345] [Impact Index Per Article: 34.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 06/24/2014] [Indexed: 12/15/2022]
Abstract
Recent studies have shown that the respiratory system has an extensive ability to respond to injury and regenerate lost or damaged cells. The unperturbed adult lung is remarkably quiescent, but after insult or injury progenitor populations can be activated or remaining cells can re-enter the cell cycle. Techniques including cell-lineage tracing and transcriptome analysis have provided novel and exciting insights into how the lungs and trachea regenerate in response to injury and have allowed the identification of pathways important in lung development and regeneration. These studies are now informing approaches for modulating the pathways that may promote endogenous regeneration as well as the generation of exogenous lung cell lineages from pluripotent stem cells. The emerging advances, highlighted in this Review, are providing new techniques and assays for basic mechanistic studies as well as generating new model systems for human disease and strategies for cell replacement.
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Affiliation(s)
- Darrell N Kotton
- 1] Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA. [2] Pulmonary Center, Boston University, Boston, Massachusetts, USA. [3] Department of Medicine, Boston University, Boston, Massachusetts, USA
| | - Edward E Morrisey
- 1] Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA. [2] Department of Cell and Developmental Biology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. [3] Cardiovascular Institute, University of Pennsylvania, Philadelphia, Pennsylvania, USA. [4] Institute for Regenerative Medicine, University of Pennsylvania Philadelphia, Pennsylvania, USA
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Aoshiba K, Tsuji T, Itoh M, Semba S, Yamaguchi K, Nakamura H, Watanabe H. A murine model of airway fibrosis induced by repeated naphthalene exposure. EXPERIMENTAL AND TOXICOLOGIC PATHOLOGY : OFFICIAL JOURNAL OF THE GESELLSCHAFT FUR TOXIKOLOGISCHE PATHOLOGIE 2014; 66:169-77. [PMID: 24480153 DOI: 10.1016/j.etp.2014.01.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 12/16/2013] [Accepted: 01/03/2014] [Indexed: 02/07/2023]
Abstract
The airway epithelium serves as a biological barrier essential for host defense against inhaled pollutants. While chronic epithelial injury, commonly associated with chronic obstructive pulmonary disease and bronchiolitis obliterans syndrome, often results in airway fibrosis, limited animal models of airway fibrosis have been established. Club cells (Clara cells) in the small airways represent an important population of epithelial progenitor cells and also the principal site of localization of the cytochrome P-450 monooxygenase system, which metabolically activates xenobiotic chemicals such as naphthalene by converting them to toxic epoxide intermediates. We hypothesized that repeated exposure to naphthalene may cause prolonged loss of club cells, triggering aberrant local epithelial repair mechanisms that lead to peribronchial fibrosis. We administered intraperitoneal injections of naphthalene to C57/BL6J mice once a week for 14 consecutive weeks. Repeated club cell injury caused by naphthalene triggered regional hyperproliferation of epithelial progenitor cells, while other regions remained denuded or squamated, resulting in fibroblast proliferation and peribronchial collagen deposition associated with upregulation of the fibrogenic cytokines transforming growth factor-β and connective tissue growth factor. The total collagen content of the lung assessed by measurement of the hydroxyproline content was also increased after repeated exposure to naphthalene. These results lend support to the relevance of repeated injury of airway epithelial cells as a trigger for resting fibroblast proliferation and airway fibrosis. This model of airway fibrosis is simple and easy to reproduce, and may be expected to advance our understanding of the pathogenesis and potential treatment of airway fibrotic disorders.
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Affiliation(s)
- Kazutetsu Aoshiba
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Japan.
| | - Takao Tsuji
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Japan
| | - Masayuki Itoh
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Japan
| | - Seitaro Semba
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Japan
| | - Kazuhiro Yamaguchi
- Comprehensive and Internal Medicine, Tokyo Women's Medical University Medical Center East, Japan
| | - Hiroyuki Nakamura
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Japan
| | - Hidehiro Watanabe
- Department of Respiratory Medicine, Tokyo Medical University Ibaraki Medical Center, Japan
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Stem cells, cell therapies, and bioengineering in lung biology and diseases. Comprehensive review of the recent literature 2010-2012. Ann Am Thorac Soc 2014; 10:S45-97. [PMID: 23869446 DOI: 10.1513/annalsats.201304-090aw] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
A conference, "Stem Cells and Cell Therapies in Lung Biology and Lung Diseases," was held July 25 to 28, 2011 at the University of Vermont to review the current understanding of the role of stem and progenitor cells in lung repair after injury and to review the current status of cell therapy and ex vivo bioengineering approaches for lung diseases. These are rapidly expanding areas of study that provide further insight into and challenge traditional views of mechanisms of lung repair after injury and pathogenesis of several lung diseases. The goals of the conference were to summarize the current state of the field, to discuss and debate current controversies, and to identify future research directions and opportunities for basic and translational research in cell-based therapies for lung diseases. The goal of this article, which accompanies the formal conference report, is to provide a comprehensive review of the published literature in lung regenerative medicine from the last conference report through December 2012.
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Bernard K, Hecker L, Luckhardt TR, Cheng G, Thannickal VJ. NADPH oxidases in lung health and disease. Antioxid Redox Signal 2014; 20:2838-53. [PMID: 24093231 PMCID: PMC4026303 DOI: 10.1089/ars.2013.5608] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
SIGNIFICANCE The evolution of the lungs and circulatory systems in vertebrates ensured the availability of molecular oxygen (O2; dioxygen) for aerobic cellular metabolism of internal organs in large animals. O2 serves as the physiologic terminal acceptor of mitochondrial electron transfer and of the NADPH oxidase (Nox) family of oxidoreductases to generate primarily water and reactive oxygen species (ROS), respectively. RECENT ADVANCES The purposeful generation of ROS by Nox family enzymes suggests important roles in normal physiology and adaptation, most notably in host defense against invading pathogens and in cellular signaling. CRITICAL ISSUES However, there is emerging evidence that, in the context of chronic stress and/or aging, Nox enzymes contribute to the pathogenesis of a number of lung diseases. FUTURE DIRECTIONS Here, we review evolving functions of Nox enzymes in normal lung physiology and emerging pathophysiologic roles in lung disease.
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Affiliation(s)
- Karen Bernard
- Division of Pulmonary, Allergy and Critical Care Medicine, Department of Medicine, University of Alabama at Birmingham , Birmingham, Alabama
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Vaughan AE, Chapman HA. Regenerative activity of the lung after epithelial injury. Biochim Biophys Acta Mol Basis Dis 2013; 1832:922-30. [DOI: 10.1016/j.bbadis.2012.11.020] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2012] [Revised: 11/21/2012] [Accepted: 11/22/2012] [Indexed: 12/22/2022]
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Sen N, Weprin S, Peter Y. Discrimination between lung homeostatic and injury-induced epithelial progenitor subsets by cell-density properties. Stem Cells Dev 2013; 22:2036-46. [PMID: 23461422 DOI: 10.1089/scd.2012.0468] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Stem/progenitor cells and their lineage derivatives are often identified by patterns and intensity of cell clusters of differentiation presentation. However, the cell biochemical façade can prove to be elusive, transient, and subject to interlaboratory disparities. To enhance current methods of lung stem cell isolation and identification and to investigate biophysical changes, which occur during homeostasis and in response to acute lung injury, we separated cells on a discontinuous density gradient, of 1.025-1.074 g/cm(3), and characterized the eluted lineages. At homeostasis, surfactant protein-C (SFTPC)-expressing cells of the alveolar type (AT)-2 lineage possessed average densities ≥1.039 g/cm(3) and aquaporin-5 producing AT1 cells equilibrated at densities <1.039 g/cm(3). While 0.74%±0.32% of lung cells were determined proliferating or postmitotic by BrdU nucleotide uptake, 73% of CD49f-, 72% of c-KIT-, and 61% of SCA-1-positive cells (putative alveolar progenitor lineage markers) showed densities ≤1.039 g/cm(3). CD49f/EpCAM(hi) progenitors, as well as c-KIT(pos)/CD45(neg) cells, could be enriched at the 1.039 g/cm(3) interface. Following acute bleomycin-induced injury, the frequency of BrdU-incorporating cells rose to 0.92%±0.36% and density could largely explain cell-lineage distribution. Specifically, a decline in the density of mitotic/postmitotic SFTPC-positive cells to ≤1.029 g/cm(3), in conjunction with an increase in CD45-positive, and proliferating CD45 and c-KIT cells in the heaviest fraction (≥1.074 g/cm(3)) were observed. These data attest to the generation of AT2 cells from low-density precursors and emphasize a relationship between cell density and molecular expression following injury, expanding on our current understanding of lung and progenitor cell dynamics.
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Affiliation(s)
- Namita Sen
- Department of Biology, Yeshiva University, New York, NY 10033, USA
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Bitterman PB, Polunovsky VA. Attacking a nexus of the oncogenic circuitry by reversing aberrant eIF4F-mediated translation. Mol Cancer Ther 2013; 11:1051-61. [PMID: 22572598 DOI: 10.1158/1535-7163.mct-11-0530] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Notwithstanding their genetic complexity, different cancers share a core group of perturbed pathways converging upon a few regulatory nodes that link the intracellular-signaling network with the basic metabolic machinery. The clear implication of this view for cancer therapy is that instead of targeting individual genetic alterations one by one, the next generation of cancer therapeutics will target critical hubs in the cancer network. One such hub is the translation-initiation complex eIF4F, which integrates several cancer-related pathways into a self-amplifying signaling system. When hyperactivated by apical oncogenic signals, the eIF4F-driven translational apparatus selectively switches the translational repertoire of a cell toward malignancy. This central integrative role of pathologically activated eIF4F has motivated the development of small-molecule inhibitors to correct its function. A genome-wide, systems-level means to objectively evaluate the pharmacologic response to therapeutics targeting eIF4F remains an unmet challenge.
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Affiliation(s)
- Peter B Bitterman
- Department of Medicine, University of Minnesota, Minneapolis, MN 55455, USA
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Abstract
Airway epithelial healing is defined as restoration of health or soundness; to cure. Our research indicates that two types of progenitor cells participate in this process: the tissue-specific stem cell (TSC) and the facultative basal progenitor (FBP). The TSC restores the epithelium to its normal structure and function. Thus, the TSC regenerates the epithelium. In contrast, the FBP-derived epithelium is characterized by regions of cellular hyperplasia and hypoplasia. Since the FBP-derived epithelium deviates from normal, we term the FBP-mediated process repair. Our work indicates that the TSC responds to signals from other epithelial cells, including the FBP. These signals instruct the TSC to proliferate or to select one of several differentiation pathways. We interpret these data in the context of Stephen Padget's "seed and soil" paradigm. Therein, Padget explained that metastasis of a tumor, the seed, to a specific site, the soil, was determined by the growth and differentiation requirements of the tumor cell. By extending the seed and soil paradigm to airway epithelial healing, we suggest that proliferation and differentiation of the TSC, the seed, is determined by its interactions with other cell types, the soil. Based on this concept, we provide a set of suggestions for development of cell-based therapies that are directed toward chronic airways disease.
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