1
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Wang F, Ting C, Riemondy KA, Douglas M, Foster K, Patel N, Kaku N, Linsalata A, Nemzek J, Varisco BM, Cohen E, Wilson JA, Riches DW, Redente EF, Toivola DM, Zhou X, Moore BB, Coulombe PA, Omary MB, Zemans RL. Regulation of epithelial transitional states in murine and human pulmonary fibrosis. J Clin Invest 2023; 133:e165612. [PMID: 37768734 PMCID: PMC10645382 DOI: 10.1172/jci165612] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 09/21/2023] [Indexed: 09/29/2023] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a progressive scarring disease arising from impaired regeneration of the alveolar epithelium after injury. During regeneration, type 2 alveolar epithelial cells (AEC2s) assume a transitional state that upregulates multiple keratins and ultimately differentiate into AEC1s. In IPF, transitional AECs accumulate with ineffectual AEC1 differentiation. However, whether and how transitional cells cause fibrosis, whether keratins regulate transitional cell accumulation and fibrosis, and why transitional AECs and fibrosis resolve in mouse models but accumulate in IPF are unclear. Here, we show that human keratin 8 (KRT8) genetic variants were associated with IPF. Krt8-/- mice were protected from fibrosis and accumulation of the transitional state. Keratin 8 (K8) regulated the expression of macrophage chemokines and macrophage recruitment. Profibrotic macrophages and myofibroblasts promoted the accumulation of transitional AECs, establishing a K8-dependent positive feedback loop driving fibrogenesis. Finally, rare murine transitional AECs were highly senescent and basaloid and may not differentiate into AEC1s, recapitulating the aberrant basaloid state in human IPF. We conclude that transitional AECs induced and were maintained by fibrosis in a K8-dependent manner; in mice, most transitional cells and fibrosis resolved, whereas in human IPF, transitional AECs evolved into an aberrant basaloid state that persisted with progressive fibrosis.
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Affiliation(s)
- Fa Wang
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Christopher Ting
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Kent A. Riemondy
- RNA Bioscience Initiative, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Michael Douglas
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Nisha Patel
- College of Literature, Science, and the Arts
| | - Norihito Kaku
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Jean Nemzek
- Unit for Laboratory Animal Medicine, School of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Brian M. Varisco
- Division of Critical Care Medicine, Cincinnati Children’s Hospital Medical Center, Cincinnati, Ohio, USA
- Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, Ohio, USA
| | - Erez Cohen
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jasmine A. Wilson
- Program in Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colorado, USA
| | - David W.H. Riches
- Program in Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
- Department of Research, Veterans Affairs Eastern Colorado Health Care System, Denver Colorado, USA
| | - Elizabeth F. Redente
- Program in Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Diana M. Toivola
- Cell Biology, Biosciences, Faculty of Science and Engineering, and InFLAMES Research Flagship Center, Åbo Akademi University, Turku, Finland
| | - Xiaofeng Zhou
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Bethany B. Moore
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan, USA
| | - Pierre A. Coulombe
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - M. Bishr Omary
- Department of Medicine, Robert Wood Johnson Medical School, New Brunswick, New Jersey, USA
| | - Rachel L. Zemans
- Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Program in Cellular and Molecular Biology, School of Medicine, and
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2
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Alysandratos KD, Garcia-de-Alba C, Yao C, Pessina P, Huang J, Villacorta-Martin C, Hix OT, Minakin K, Burgess CL, Bawa P, Murthy A, Konda B, Beers MF, Stripp BR, Kim CF, Kotton DN. Culture impact on the transcriptomic programs of primary and iPSC-derived human alveolar type 2 cells. JCI Insight 2023; 8:e158937. [PMID: 36454643 PMCID: PMC9870086 DOI: 10.1172/jci.insight.158937] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 11/21/2022] [Indexed: 12/02/2022] Open
Abstract
Dysfunction of alveolar epithelial type 2 cells (AEC2s), the facultative progenitors of lung alveoli, is implicated in pulmonary disease pathogenesis, highlighting the importance of human in vitro models. However, AEC2-like cells in culture have yet to be directly compared to their in vivo counterparts at single-cell resolution. Here, we performed head-to-head comparisons among the transcriptomes of primary (1°) adult human AEC2s, their cultured progeny, and human induced pluripotent stem cell-derived AEC2s (iAEC2s). We found each population occupied a distinct transcriptomic space with cultured AEC2s (1° and iAEC2s) exhibiting similarities to and differences from freshly purified 1° cells. Across each cell type, we found an inverse relationship between proliferative and maturation states, with preculture 1° AEC2s being most quiescent/mature and iAEC2s being most proliferative/least mature. Cultures of either type of human AEC2s did not generate detectable alveolar type 1 cells in these defined conditions; however, a subset of iAEC2s cocultured with fibroblasts acquired a transitional cell state described in mice and humans to arise during fibrosis or following injury. Hence, we provide direct comparisons of the transcriptomic programs of 1° and engineered AEC2s, 2 in vitro models that can be harnessed to study human lung health and disease.
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Affiliation(s)
- Konstantinos-Dionysios Alysandratos
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Carolina Garcia-de-Alba
- Stem Cell Program and Divisions of Hematology/Oncology and Pulmonary Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Changfu Yao
- Women’s Guild Lung Institute
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Patrizia Pessina
- Stem Cell Program and Divisions of Hematology/Oncology and Pulmonary Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
- Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, Texas, USA
| | - Jessie Huang
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Carlos Villacorta-Martin
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Olivia T. Hix
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
| | - Kasey Minakin
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
| | - Claire L. Burgess
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
| | - Pushpinder Bawa
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
| | - Aditi Murthy
- Pulmonary, Allergy, and Critical Care Division, Department of Medicine, and
- PENN-CHOP Lung Biology Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Bindu Konda
- Women’s Guild Lung Institute
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Michael F. Beers
- Pulmonary, Allergy, and Critical Care Division, Department of Medicine, and
- PENN-CHOP Lung Biology Institute, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania, USA
| | - Barry R. Stripp
- Women’s Guild Lung Institute
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, and
- Regenerative Medicine Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Carla F. Kim
- Stem Cell Program and Divisions of Hematology/Oncology and Pulmonary Medicine, Boston Children’s Hospital, Boston, Massachusetts, USA
- Harvard Stem Cell Institute, Cambridge, Massachusetts, USA
- Department of Genetics, Harvard Medical School, Boston, Massachusetts, USA
| | - Darrell N. Kotton
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, Massachusetts, USA
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3
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Yamano S, Takeda T, Goto Y, Hirai S, Furukawa Y, Kikuchi Y, Misumi K, Suzuki M, Takanobu K, Senoh H, Saito M, Kondo H, Kobashi Y, Okamoto K, Kishimoto T, Umeda Y. Mechanisms of pulmonary disease in F344 rats after workplace-relevant inhalation exposure to cross-linked water-soluble acrylic acid polymers. Respir Res 2023; 24:47. [PMID: 36782232 PMCID: PMC9926550 DOI: 10.1186/s12931-023-02355-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 02/01/2023] [Indexed: 02/15/2023] Open
Abstract
BACKGROUND Recently in Japan, six workers at a chemical plant that manufactures resins developed interstitial lung diseases after being involved in loading and packing cross-linked water-soluble acrylic acid polymers (CWAAPs). The present study focused on assessing lung damage in rats caused by workplace-relevant inhalation exposure to CWAAP and investigated the molecular and cellular mechanisms involved in lung lesion development. METHODS Using a whole-body inhalation exposure system, male F344 rats were exposed once to 40 or 100 mg/m3 of CWAAP-A for 4 h or to 15 or 40 mg/m3 of CWAAP-A for 4 h per day once per week for 2 months (9 exposures). In a separate set of experiments, male F344 rats were administered 1 mg/kg CWAAP-A or CWAAP-B by intratracheal instillation once every 2 weeks for 2 months (5 doses). Lung tissues, mediastinal lymph nodes, and bronchoalveolar lavage fluid were collected and subjected to biological and histopathological analyses. RESULTS A single 4-h exposure to CWAAP-A caused alveolar injury, and repeated exposures resulted in regenerative changes in the alveolar epithelium with activation of TGFβ signaling. During the recovery period after the last exposure, some alveolar lesions were partially healed, but other lesions developed into alveolitis with fibrous thickening of the alveolar septum. Rats administered CWAAP-A by intratracheal instillation developed qualitatively similar pulmonary pathology as rats exposed to CWAAP-A by inhalation. At 2 weeks after intratracheal instillation, rats administered CWAAP-B appeared to have a slightly higher degree of lung lesions compared to rats administered CWAAP-A, however, there was no difference in pulmonary lesions in the CWAAP-A and CWAAP-B exposed rats examined 18 weeks after administration of these materials. CONCLUSIONS The present study reports our findings on the cellular and molecular mechanisms of pulmonary disease in rats after workplace-relevant inhalation exposure to CWAAP-A. This study also demonstrates that the lung pathogenesis of rats exposed to CWAAP-A by systemic inhalation was qualitatively similar to that of rats administered CWAAP-A by intratracheal instillation.
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Affiliation(s)
- Shotaro Yamano
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa, 257-0015, Japan.
| | - Tomoki Takeda
- Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa, 257-0015, Japan.
| | - Yuko Goto
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Shigeyuki Hirai
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Yusuke Furukawa
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Yoshinori Kikuchi
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Kyohei Misumi
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Masaaki Suzuki
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Kenji Takanobu
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Hideki Senoh
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Misae Saito
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Hitomi Kondo
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
| | - Yoichiro Kobashi
- grid.416952.d0000 0004 0378 4277Department of Pathology, Tenri Hospital, Tenri, Nara 632-8552 Japan
| | - Kenzo Okamoto
- grid.505713.50000 0000 8626 1412Department of Pathology, Hokkaido Chuo Rosai Hospital, Japan Organization of Occupational Health and Safety, Iwamizawa, Hokkaido 068-0004 Japan
| | - Takumi Kishimoto
- Director of Research and Training Center for Asbestos-Related Diseases, Okayama, Okayama 702-8055 Japan
| | - Yumi Umeda
- grid.505713.50000 0000 8626 1412Japan Bioassay Research Center, Japan Organization of Occupational Health and Safety, Hadano, Kanagawa 257-0015 Japan
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4
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Gonzalez R, Leaffer D, Chapin C, Gillespie AM, Eckalbar W, Dobbs L. Cell fate analysis in fetal mouse lung reveals distinct pathways for TI and TII cell development. Am J Physiol Lung Cell Mol Physiol 2019; 317:L653-L666. [PMID: 31432712 DOI: 10.1152/ajplung.00503.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alveolar type I (TI) cells are large squamous cells that cover >95% of the internal surface area of the lung; type II (TII) cells are small cuboidal cells with distinctive intracellular surfactant storage organelles. Based on autoradiographic studies in the 1970s, the long-held paradigm of alveolar epithelial development has been a linear progression from undifferentiated progenitor cells through TII cells to TI cells. Subsequent data support the existence of more complex pathways. Recently, a bipotent TI/TII progenitor cell at embryonic day E18 has been inferred both from marker expression in developing airways and from statistical analyses of gene expression data obtained from single-lung embryonic cells. To study cell lineage directly by fate mapping, we developed new transgenic mouse models in which rtTA is driven either by the rat podoplanin or the mouse Sftpc gene to mark cells irreversibly in development. Using these models, we found two distinct lineage pathways. One pathway, evident as early as E12-15, is devoted almost exclusively to TI cell development; a second pathway gives rise predominantly to TII cells but also a subpopulation of TI cells. We have defined the molecular phenotypes of these distinct progenitor populations and have identified potential regulatory factors in TI and TII cell differentiation. By analyzing gene pathways in mature TI and TII cells, we identified potential novel functions of each cell type. These results provide novel insights into lung development and suggest a basis for testing strategies to promote alveolar differentiation and repair, including potential transplantation of lineage-specific progenitor cells.
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Affiliation(s)
- Robert Gonzalez
- Cardiovascular Research Institute, University of California, San Francisco, California
| | - David Leaffer
- Cardiovascular Research Institute, University of California, San Francisco, California
| | - Cheryl Chapin
- Department of Pediatrics, University of California, San Francisco, California
| | - Anne Marie Gillespie
- Cardiovascular Research Institute, University of California, San Francisco, California
| | - Walter Eckalbar
- Department of Medicine, University of California, San Francisco, California
| | - Leland Dobbs
- Cardiovascular Research Institute, University of California, San Francisco, California.,Department of Pediatrics, University of California, San Francisco, California.,Department of Medicine, University of California, San Francisco, California
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5
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Correll KA, Edeen KE, Zemans RL, Redente EF, Serban KA, Curran-Everett D, Edelman BL, Mikels-Vigdal A, Mason RJ. Transitional human alveolar type II epithelial cells suppress extracellular matrix and growth factor gene expression in lung fibroblasts. Am J Physiol Lung Cell Mol Physiol 2019; 317:L283-L294. [PMID: 31166130 DOI: 10.1152/ajplung.00337.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Epithelial-fibroblast interactions are thought to be very important in the adult lung in response to injury, but the specifics of these interactions are not well defined. We developed coculture systems to define the interactions of adult human alveolar epithelial cells with lung fibroblasts. Alveolar type II cells cultured on floating collagen gels reduced the expression of type 1 collagen (COL1A1) and α-smooth muscle actin (ACTA2) in fibroblasts. They also reduced fibroblast expression of hepatocyte growth factor (HGF), fibroblast growth factor 7 (FGF7, KGF), and FGF10. When type II cells were cultured at an air-liquid interface to maintain high levels of surfactant protein expression, this inhibitory activity was lost. When type II cells were cultured on collagen-coated tissue culture wells to reduce surfactant protein expression further and increase the expression of some type I cell markers, the epithelial cells suppressed transforming growth factor-β (TGF-β)-stimulated ACTA2 and connective tissue growth factor (CTGF) expression in lung fibroblasts. Our results suggest that transitional alveolar type II cells and likely type I cells but not fully differentiated type II cells inhibit matrix and growth factor expression in fibroblasts. These cells express markers of both type II cells and type I cells. This is probably a normal homeostatic mechanism to inhibit the fibrotic response in the resolution phase of wound healing. Defining how transitional type II cells convert activated fibroblasts into a quiescent state and inhibit the effects of TGF-β may provide another approach to limiting the development of fibrosis after alveolar injury.
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Affiliation(s)
| | | | - Rachel L Zemans
- National Jewish Health, Denver, Colorado.,Division of Pulmonary and Critical Care Medicine/Department of Medicine, University of Michigan, Ann Arbor, Michigan
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6
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Riemondy KA, Jansing NL, Jiang P, Redente EF, Gillen AE, Fu R, Miller AJ, Spence JR, Gerber AN, Hesselberth JR, Zemans RL. Single cell RNA sequencing identifies TGFβ as a key regenerative cue following LPS-induced lung injury. JCI Insight 2019; 5:123637. [PMID: 30913038 PMCID: PMC6538357 DOI: 10.1172/jci.insight.123637] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Accepted: 03/07/2019] [Indexed: 12/12/2022] Open
Abstract
Many lung diseases result from a failure of efficient regeneration of damaged alveolar epithelial cells (AECs) after lung injury. During regeneration, AEC2s proliferate to replace lost cells, after which proliferation halts and some AEC2s transdifferentiate into AEC1s to restore normal alveolar structure and function. Although the mechanisms underlying AEC2 proliferation have been studied, the mechanisms responsible for halting proliferation and inducing transdifferentiation are poorly understood. To identify candidate signaling pathways responsible for halting proliferation and inducing transdifferentiation, we performed single cell RNA sequencing on AEC2s during regeneration in a murine model of lung injury induced by intratracheal LPS. Unsupervised clustering revealed distinct subpopulations of regenerating AEC2s: proliferating, cell cycle arrest, and transdifferentiating. Gene expression analysis of these transitional subpopulations revealed that TGFβ signaling was highly upregulated in the cell cycle arrest subpopulation and relatively downregulated in transdifferentiating cells. In cultured AEC2s, TGFβ was necessary for cell cycle arrest but impeded transdifferentiation. We conclude that during regeneration after LPS-induced lung injury, TGFβ is a critical signal halting AEC2 proliferation but must be inactivated to allow transdifferentiation. This study provides insight into the molecular mechanisms regulating alveolar regeneration and the pathogenesis of diseases resulting from a failure of regeneration.
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Affiliation(s)
- Kent A. Riemondy
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Nicole L. Jansing
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado, USA
| | - Peng Jiang
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Elizabeth F. Redente
- Program in Cell Biology, Department of Pediatrics, National Jewish Health, Denver, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Austin E. Gillen
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Rui Fu
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Alyssa J. Miller
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jason R. Spence
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA
- Division of Gastroenterology, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Department of Cell and Developmental Biology, University of Michigan, Ann Arbor, Michigan, USA
| | - Anthony N. Gerber
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Jay R. Hesselberth
- RNA Bioscience Initiative, University of Colorado School of Medicine, Aurora, Colorado, USA
| | - Rachel L. Zemans
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, Colorado, USA
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA
- Division of Pulmonary Sciences and Critical Care Medicine, University of Colorado Denver, Aurora, Colorado, USA
- Program in Cellular and Molecular Biology, University of Michigan, Ann Arbor, Michigan, USA
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7
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Rizvi ZA, Puri N, Saxena RK. Evidence of CD1d pathway of lipid antigen presentation in mouse primary lung epithelial cells and its up-regulation upon Mycobacterium bovis BCG infection. PLoS One 2018; 13:e0210116. [PMID: 30596774 PMCID: PMC6312317 DOI: 10.1371/journal.pone.0210116] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Accepted: 12/17/2018] [Indexed: 01/01/2023] Open
Abstract
Presentation of a prototype lipid antigen α-Galactosylceramide (αGC) was examined on primary epithelial cells derived from mouse lungs and on bronchoalveolar lavage (BAL) cells that essentially comprise alveolar macrophages. Presence of CD1d molecules coupled to αGC was demonstrated on both types of cells pre-treated with αGC, suggesting that both cell types are equipped to present lipid antigens. Internalization of Mycobacterium bovis Bacillus Calmette–Guérin (BCG: a prototype pathogen), a pre-requisite to the processing and presentation of protein as well as lipid antigens, was clearly demonstrated in primary lung epithelial (PLE) cells as well as BAL cells. Both PLE and BAL cells expressed CD1d molecule and a significant up-regulation of its expression occurred upon infection of these cells with BCG. Besides CD1d, the expression of other important molecules that participate in lipid antigen presentation pathway (i.e. microsomal triglyceride transfer protein (MTTP), scavenger receptor B1 (SR-B1) and Saposin) was also significantly upregulated in PLE and BAL cells upon BCG infection. In situ up-regulation of CD1d expression on lung epithelial cells was also demonstrated in the lungs of mice exposed intra-tracheally to BCG. Taken together these results suggest that lung epithelial cells may have the ability to present lipid antigens and this pathway seems to get significantly upregulated in response to BCG infection.
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Affiliation(s)
- Zaigham Abbas Rizvi
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, Delhi, India
| | - Niti Puri
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, Delhi, India
- * E-mail:
| | - Rajiv K. Saxena
- Faculty of Life Sciences and Biotechnology, South Asian University, New Delhi, Delhi, India
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8
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Sapich S, Hittinger M, Hendrix-Jastrzebski R, Repnik U, Griffiths G, May T, Wirth D, Bals R, Schneider-Daum N, Lehr CM. Murine alveolar epithelial cells and their lentivirus-mediated immortalisation. Altern Lab Anim 2018; 46:73-89. [PMID: 29856645 DOI: 10.1177/026119291804600207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study, we describe the isolation and immortalisation of primary murine alveolar epithelial cells (mAEpC), as well as their epithelial differentiation and barrier properties when grown on Transwell® inserts. Like human alveolar epithelial cells (hAEpC), mAEpC transdifferentiate in vitro from an alveolar type II (ATII) phenotype to an ATI-like phenotype and exhibit features of the air-blood barrier, such as the establishment of a thin monolayer with functional tight junctions (TJs). This is demonstrated by the expression of TJ proteins (ZO-1 and occludin) and the development of high transepithelial electrical resistance (TEER), peaking at 1800Ω ·cm². Transport across the air-blood barrier, for general toxicity assessments or preclinical drug development, is typically studied in mice. The aim of this work was the generation of novel immortalised murine lung cell lines, to help meet Three Rs requirements in experimental testing and research. To achieve this goal, we lentivirally transduced mAEpC of two different mouse strains with a library of 33 proliferation-promoting genes. With this immortalisation approach, we obtained two murine alveolar epithelial lentivirus-immortalised (mAELVi) cell lines. Both showed similar TJ protein localisation, but exhibited less prominent barrier properties (TEERmax ~250Ω·cm²) when compared to their primary counterparts. While mAEpC demonstrated their suitability for use in the assessment of paracellular transport rates, mAELVi cells could potentially replace mice for the prediction of acute inhalation toxicity during early ADMET studies.
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Affiliation(s)
- Sandra Sapich
- Department of Drug Delivery (DDEL), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz-Centre for Infection Research (HZI ), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | | | - Remi Hendrix-Jastrzebski
- Department of Drug Delivery (DDEL), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz-Centre for Infection Research (HZI ), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany
| | - Urska Repnik
- Department of Biosciences, University of Oslo, Oslo, Norway
| | | | | | - Dagmar Wirth
- Research Group Model Systems for Infection and Immunity (MSYS), Helmholtz-Centre for Infection Research (HZI), Braunschweig, Germany; Institute of Experimental Haematology, Medical School Hannover, Hannover, Germany
| | - Robert Bals
- Department of Internal Medicine V - Pulmonology, Allergology and Respiratory Critical Care Medicine, Saarland University, Homburg (Saar), Germany
| | - Nicole Schneider-Daum
- Department of Drug Delivery (DDEL), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz-Centre for Infection Research (HZI ), Saarbrücken, Germany
| | - Claus-Michael Lehr
- Department of Drug Delivery (DDEL), Helmholtz-Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz-Centre for Infection Research (HZI ), Saarbrücken, Germany; Department of Pharmacy, Saarland University, Saarbrücken, Germany; PharmBioTec GmbH, Saarbrücken, Germany
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9
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Bonniaud P, Fabre A, Frossard N, Guignabert C, Inman M, Kuebler WM, Maes T, Shi W, Stampfli M, Uhlig S, White E, Witzenrath M, Bellaye PS, Crestani B, Eickelberg O, Fehrenbach H, Guenther A, Jenkins G, Joos G, Magnan A, Maitre B, Maus UA, Reinhold P, Vernooy JHJ, Richeldi L, Kolb M. Optimising experimental research in respiratory diseases: an ERS statement. Eur Respir J 2018; 51:13993003.02133-2017. [PMID: 29773606 DOI: 10.1183/13993003.02133-2017] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 04/02/2018] [Indexed: 12/15/2022]
Abstract
Experimental models are critical for the understanding of lung health and disease and are indispensable for drug development. However, the pathogenetic and clinical relevance of the models is often unclear. Further, the use of animals in biomedical research is controversial from an ethical perspective.The objective of this task force was to issue a statement with research recommendations about lung disease models by facilitating in-depth discussions between respiratory scientists, and to provide an overview of the literature on the available models. Focus was put on their specific benefits and limitations. This will result in more efficient use of resources and greater reduction in the numbers of animals employed, thereby enhancing the ethical standards and translational capacity of experimental research.The task force statement addresses general issues of experimental research (ethics, species, sex, age, ex vivo and in vitro models, gene editing). The statement also includes research recommendations on modelling asthma, chronic obstructive pulmonary disease, pulmonary fibrosis, lung infections, acute lung injury and pulmonary hypertension.The task force stressed the importance of using multiple models to strengthen validity of results, the need to increase the availability of human tissues and the importance of standard operating procedures and data quality.
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Affiliation(s)
- Philippe Bonniaud
- Service de Pneumologie et Soins Intensifs Respiratoires, Centre Hospitalo-Universitaire de Bourgogne, Dijon, France.,Faculté de Médecine et Pharmacie, Université de Bourgogne-Franche Comté, Dijon, France.,INSERM U866, Dijon, France
| | - Aurélie Fabre
- Dept of Histopathology, St Vincent's University Hospital, UCD School of Medicine, University College Dublin, Dublin, Ireland
| | - Nelly Frossard
- Laboratoire d'Innovation Thérapeutique, Université de Strasbourg, Strasbourg, France.,CNRS UMR 7200, Faculté de Pharmacie, Illkirch, France.,Labex MEDALIS, Université de Strasbourg, Strasbourg, France
| | - Christophe Guignabert
- INSERM UMR_S 999, Le Plessis-Robinson, France.,Université Paris-Sud and Université Paris-Saclay, Le Kremlin-Bicêtre, France
| | - Mark Inman
- Dept of Medicine, Firestone Institute for Respiratory Health at St Joseph's Health Care MDCL 4011, McMaster University, Hamilton, ON, Canada
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Tania Maes
- Dept of Respiratory Medicine, Laboratory for Translational Research in Obstructive Pulmonary Diseases, Ghent University Hospital, Ghent, Belgium
| | - Wei Shi
- Developmental Biology and Regenerative Medicine Program, The Saban Research Institute of Children's Hospital Los Angeles, Los Angeles, CA, USA.,Dept of Surgery, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Martin Stampfli
- Dept of Medicine, Firestone Institute for Respiratory Health at St Joseph's Health Care MDCL 4011, McMaster University, Hamilton, ON, Canada.,Dept of Pathology and Molecular Medicine, McMaster Immunology Research Centre, McMaster University
| | - Stefan Uhlig
- Institute of Pharmacology and Toxicology, RWTH Aachen University, Aachen, Germany
| | - Eric White
- Division of Pulmonary and Critical Care Medicine, Dept of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, USA
| | - Martin Witzenrath
- Dept of Infectious Diseases and Respiratory Medicine And Division of Pulmonary Inflammation, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Pierre-Simon Bellaye
- Département de Médecine nucléaire, Plateforme d'imagerie préclinique, Centre George-François Leclerc (CGFL), Dijon, France
| | - Bruno Crestani
- Assistance Publique-Hôpitaux de Paris, Hôpital Bichat, DHU FIRE, Service de Pneumologie A, Paris, France.,INSERM UMR 1152, Paris, France.,Université Paris Diderot, Paris, France
| | - Oliver Eickelberg
- Division of Pulmonary Sciences and Critical Care Medicine, Dept of Medicine, University of Colorado, Aurora, CO, USA
| | - Heinz Fehrenbach
- Priority Area Asthma & Allergy, Research Center Borstel, Airway Research Center North (ARCN), German Center for Lung Research (DZL), Borstel, Germany.,Member of the Leibniz Research Alliance Health Technologies
| | - Andreas Guenther
- Justus-Liebig-University Giessen, Universitary Hospital Giessen, Agaplesion Lung Clinic Waldhof-Elgershausen, German Center for Lung Research, Giessen, Germany
| | - Gisli Jenkins
- Nottingham Biomedical Research Centre, Respiratory Research Unit, City Campus, University of Nottingham, Nottingham, UK
| | - Guy Joos
- Dept of Respiratory Medicine, Ghent University Hospital, Ghent, Belgium
| | - Antoine Magnan
- Institut du thorax, CHU de Nantes, Université de Nantes, Nantes, France
| | - Bernard Maitre
- Hôpital H Mondor, AP-HP, Centre Hospitalier Intercommunal de Créteil, Service de Pneumologie et de Pathologie Professionnelle, DHU A-TVB, Université Paris Est - Créteil, Créteil, France
| | - Ulrich A Maus
- Hannover School of Medicine, Division of Experimental Pneumology, Hannover, Germany
| | - Petra Reinhold
- Institute of Molecular Pathogenesis at the 'Friedrich-Loeffler-Institut' (Federal Research Institute for Animal Health), Jena, Germany
| | - Juanita H J Vernooy
- Dept of Respiratory Medicine, Maastricht University Medical Center+ (MUMC+), AZ Maastricht, The Netherlands
| | - Luca Richeldi
- UOC Pneumologia, Università Cattolica del Sacro Cuore, Fondazione Policlinico Universitario "A. Gemelli", Rome, Italy
| | - Martin Kolb
- Dept of Medicine, Firestone Institute for Respiratory Health at St Joseph's Health Care MDCL 4011, McMaster University, Hamilton, ON, Canada
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10
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Receptor for advanced glycation endproducts (RAGE) maintains pulmonary structure and regulates the response to cigarette smoke. PLoS One 2017; 12:e0180092. [PMID: 28678851 PMCID: PMC5497997 DOI: 10.1371/journal.pone.0180092] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 06/09/2017] [Indexed: 12/15/2022] Open
Abstract
The receptor for advanced glycation endproducts (RAGE) is highly expressed in the lung but its physiological functions in this organ is still not completely understood. To determine the contribution of RAGE to physiological functions of the lung, we analyzed pulmonary mechanics and structure of wildtype and RAGE deficient (RAGE-/-) mice. RAGE deficiency spontaneously resulted in a loss of lung structure shown by an increased mean chord length, increased respiratory system compliance, decreased respiratory system elastance and increased concentrations of serum protein albumin in bronchoalveolar lavage fluids. Pulmonary expression of RAGE was mainly localized on alveolar epithelial cells and alveolar macrophages. Primary murine alveolar epithelial cells isolated from RAGE-/- mice revealed an altered differentiation and defective barrier formation under in vitro conditions. Stimulation of interferone-y (IFNy)-activated alveolar macrophages deficient for RAGE with Toll-like receptor (TLR) ligands resulted in significantly decreased release of proinflammatory cytokines and chemokines. Exposure to chronic cigarette smoke did not affect emphysema-like changes in lung parenchyma in RAGE-/- mice. Acute cigarette smoke exposure revealed a modified inflammatory response in RAGE-/- mice that was characterized by an influx of macrophages and a decreased keratinocyte-derived chemokine (KC) release. Our data suggest that RAGE regulates the differentiation of alveolar epithelial cells and impacts on the development and maintenance of pulmonary structure. In cigarette smoke-induced lung pathology, RAGE mediates inflammation that contributes to lung damage.
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11
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12
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13
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Yang J, Hernandez BJ, Martinez Alanis D, Narvaez del Pilar O, Vila-Ellis L, Akiyama H, Evans SE, Ostrin EJ, Chen J. The development and plasticity of alveolar type 1 cells. Development 2015; 143:54-65. [PMID: 26586225 DOI: 10.1242/dev.130005] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Accepted: 11/11/2015] [Indexed: 12/16/2022]
Abstract
Alveolar type 1 (AT1) cells cover >95% of the gas exchange surface and are extremely thin to facilitate passive gas diffusion. The development of these highly specialized cells and its coordination with the formation of the honeycomb-like alveolar structure are poorly understood. Using new marker-based stereology and single-cell imaging methods, we show that AT1 cells in the mouse lung form expansive thin cellular extensions via a non-proliferative two-step process while retaining cellular plasticity. In the flattening step, AT1 cells undergo molecular specification and remodel cell junctions while remaining connected to their epithelial neighbors. In the folding step, AT1 cells increase in size by more than 10-fold and undergo cellular morphogenesis that matches capillary and secondary septa formation, resulting in a single AT1 cell spanning multiple alveoli. Furthermore, AT1 cells are an unexpected source of VEGFA and their normal development is required for alveolar angiogenesis. Notably, a majority of AT1 cells proliferate upon ectopic SOX2 expression and undergo stage-dependent cell fate reprogramming. These results provide evidence that AT1 cells have both structural and signaling roles in alveolar maturation and can exit their terminally differentiated non-proliferative state. Our findings suggest that AT1 cells might be a new target in the pathogenesis and treatment of lung diseases associated with premature birth.
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Affiliation(s)
- Jun Yang
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Belinda J Hernandez
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Denise Martinez Alanis
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | | | - Lisandra Vila-Ellis
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA Tecnologico de Monterrey - Escuela de Medicina, Monterrey 64710, Mexico
| | - Haruhiko Akiyama
- Department of Orthopedics, Kyoto University, Sakyo, Kyoto 606-8507, Japan
| | - Scott E Evans
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Edwin J Ostrin
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Jichao Chen
- Department of Pulmonary Medicine, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA Center for Stem Cells and Developmental Biology, The University of Texas M. D. Anderson Cancer Center, Houston, TX 77030, USA
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14
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Xu W, Xu B, Zhao Y, Yang N, Liu C, Wen G, Zhang B. Wnt5a reverses the inhibitory effect of hyperoxia on transdifferentiation of alveolar epithelial type II cells to type I cells. J Physiol Biochem 2015; 71:823-38. [PMID: 26547443 DOI: 10.1007/s13105-015-0446-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 10/27/2015] [Indexed: 11/26/2022]
Abstract
Transdifferentiation of alveolar epithelial type II cells (AECIIs) to type I cells (AECIs) is critical for reestablishment and maintenance of an intact alveolar epithelium. However, this process is frequently destroyed by hyperoxia treatment, which is commonly used in respiratory distress syndrome therapy in preterm infants. Wnt5a is considered to participate in this physiopathologic process, but the clear mechanisms still need to be further investigated. In this study, preterm rats and primary rat AECIIs were exposed to hyperoxia. Hematoxylin and eosin staining was used to examine the histological changes of the lungs. Real-time PCR and western blotting were used to examine Wnt5a expression and biomarkers of AECII and AECI expression. Immunohistochemistry and immunofluorescence were also used to determine the expression and location of selected biomarkers. Furthermore, AECIIs transfected with Wnt5a gene and exogenous Wnt5a were used to examine whether Wnt5a contributes to the transdifferentiation of AECIIs to AECIs. Results showed that hyperoxia inhibited the transdifferentiation of AECIIs to AECIs in vitro, which is represented by biomarkers of two types of cell that remained unchanged. In addition, Wnt5a protein expression was found to be decreased after hyperoxia exposure in vitro and in vivo. Furthermore, both the overexpression of Wnt5a and exogenous Wnt5a addition blocked the inhibitory effect of hyperoxia in vitro. In conclusion, our results suggest that the transdifferentiation of AECIIs to AECIs is impaired by hyperoxia, and this process may be associated with Wnt5a downregulation. Targeting Wnt5a may have the potential for the therapy of lung injury in preterm infants induced by hyperoxia.
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Affiliation(s)
- Wei Xu
- Department of Pediatrics, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China.
| | - Bo Xu
- Department of Ophthalmology, The Affiliated People's Hospital of Jiangsu University, Zhenjiang, Jiangsu, 212002, People's Republic of China
| | - Ying Zhao
- Department of Pediatrics, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Ni Yang
- Department of Pediatrics, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Chunfeng Liu
- Department of Pediatrics, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Guangfu Wen
- Department of Pediatrics, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
| | - Binglun Zhang
- Department of Pediatrics, Shengjing Hospital of China Medical University, 36 Sanhao Street, Shenyang, Liaoning, 110004, People's Republic of China
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15
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Abstract
Pulmonary edema clearance is necessary for patients with lung injury to recover and survive. The mechanisms regulating edema clearance from the lungs are distinct from the factors contributing edema formation during injury. Edema clearance is effected via vectorial transport of Na(+) out of the airspaces which generates an osmotic gradient causing water to follow the gradient out of the cells. This Na(+) transport across the alveolar epithelium is mostly effected via apical Na(+) and chloride channels and basolateral Na,K-ATPase. The Na,K-ATPase pumps Na(+) out of the cell and K(+) into the cell against their respective gradients in an ATP-consuming reaction. Two mechanisms contribute to the regulation of the Na,K-ATPase activity:recruitment of its subunits from intracellular compartments into the basolateral membrane, and transcriptional/translational regulation. Na,K-ATPase activity and edema clearance are increased by catecholamines, aldosterone, vasopressin, overexpression of the pump genes, and others. During lung injury, mechanisms regulating edema clearance are inhibited by yet unclear pathways. Better understanding of the mechanisms that regulate pulmonary edema clearance may lead to therapeutic interventions that counterbalance the inhibition of edema clearance during lung injury and improve the lungs' ability to clear fluid, which is crucial for patient survival.
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Affiliation(s)
- Zaher S. Azzam
- Internal Medicine “B”, Rambam Health Care Campus, Department of Physiology and Biophysics, The Rappaport Family Faculty of Medicine and Research Institute, Technion, Israel Institute of Technology, Haifa, Israel
| | - Jacob I. Sznajder
- Division of Pulmonary and Critical Care Medicine, Northwestern University, Chicago, IL, USA
- To whom correspondence should be addressed. E-mail:
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16
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Kebaabetswe LP, Haick AK, Gritsenko MA, Fillmore TL, Chu RK, Purvine SO, Webb-Robertson BJ, Matzke MM, Smith RD, Waters KM, Metz TO, Miura TA. Proteomic analysis reveals down-regulation of surfactant protein B in murine type II pneumocytes infected with influenza A virus. Virology 2015; 483:96-107. [PMID: 25965799 DOI: 10.1016/j.virol.2015.03.045] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 01/13/2015] [Accepted: 03/18/2015] [Indexed: 11/29/2022]
Abstract
Infection of type II alveolar epithelial (ATII) cells by influenza A viruses (IAV) correlates with severe respiratory disease in humans and mice. To understand pathogenic mechanisms during IAV infection of ATII cells, murine ATII cells were cultured to maintain a differentiated phenotype, infected with IAV-PR8, which causes severe lung pathology in mice, and proteomics analyses were performed using liquid chromatography-mass spectrometry. PR8 infection increased levels of proteins involved in interferon signaling, antigen presentation, and cytoskeleton regulation. Proteins involved in mitochondrial membrane permeability, energy metabolism, and chromatin formation had reduced levels in PR8-infected cells. Phenotypic markers of ATII cells in vivo were identified, confirming the differentiation status of the cultures. Surfactant protein B had decreased levels in PR8-infected cells, which was confirmed by immunoblotting and immunofluorescence assays. Analysis of ATII cell protein profiles will elucidate cellular processes in IAV pathogenesis, which may provide insight into potential therapies to modulate disease severity.
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Affiliation(s)
- Lemme P Kebaabetswe
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Anoria K Haick
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA
| | - Marina A Gritsenko
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Thomas L Fillmore
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Rosalie K Chu
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Samuel O Purvine
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Bobbie-Jo Webb-Robertson
- Computational and Statistical Analytics Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Melissa M Matzke
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Richard D Smith
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Katrina M Waters
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Thomas O Metz
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | - Tanya A Miura
- Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA.
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17
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Calle EA, Mendez JJ, Ghaedi M, Leiby KL, Bove PF, Herzog EL, Sundaram S, Niklason LE. Fate of distal lung epithelium cultured in a decellularized lung extracellular matrix. Tissue Eng Part A 2015; 21:1916-28. [PMID: 25789725 DOI: 10.1089/ten.tea.2014.0511] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Type II cells are the defenders of the alveolus. They produce surfactant to prevent alveolar collapse, they actively transport water to prevent filling of the air sacs that would otherwise prevent gas exchange, and they differentiate to type I epithelial cells. They are an indispensable component of functional lung tissue. To understand the functionality of type II cells in isolation, we sought to track their fate in decellularized matrices and to assess their ability to contribute to barrier function by differentiation to type I alveolar epithelial cells. Rat type II cells were isolated from neonatal rat lungs by labeling with the RTII-70 surface marker and separation using a magnetic column. This produced a population of ∼50% RTII-70-positive cells accompanied by few type I epithelial cells or α-actin-positive mesenchymal cells. This population was seeded into decellularized rat lung matrices and cultured for 1 or 7 days. Culture in Dulbecco's modified Eagle's medium +10% fetal bovine serum (FBS) resulted in reduced expression of epithelial markers and increased expression of mesenchymal markers. By 7 days, no epithelial markers were visible by immunostaining; nearly all cells were α-actin positive. Gene expression for the mesenchymal markers, α-actin, vimentin, and TGF-βR, was significantly upregulated on day 1 (p=0.0005, 0.0005, and 2.342E-5, respectively). Transcript levels of α-actin and TGF-βR remained high at 7 days (p=1.364E-10 and 0.0002). Interestingly, human type II cells cultured under the same conditions showed a similar trend in the loss of epithelial markers, but did not display high expression of mesenchymal markers. Rat cells additionally showed the ability to produce and degrade the basement membrane and extracellular matrix components, such as fibronectin, collagen IV, and collagen I. Quantitative real-time reverse transcription polymerase chain reaction (RT-PCR) showed significant increases in expression of the fibronectin and matrix metalloprotease-2 (MMP-2) genes after 1 day in culture (p=0.0135 and 0.0128, respectively) and elevated collagen I expression at 7 days (p=0.0016). These data suggest that the original type II-enriched population underwent a transition to increased expression of mesenchymal markers, perhaps as part of a survival or wound-healing program. These results suggest that additional medium components and/or the application of physiologically appropriate stimuli such as ventilation may be required to promote lung-specific epithelial phenotypes.
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Affiliation(s)
- Elizabeth A Calle
- 1Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Julio J Mendez
- 2Department of Anesthesia, Yale University School of Medicine, New Haven, Connecticut
| | - Mahboobe Ghaedi
- 2Department of Anesthesia, Yale University School of Medicine, New Haven, Connecticut
| | - Katherine L Leiby
- 1Department of Biomedical Engineering, Yale University, New Haven, Connecticut
| | - Peter F Bove
- 3Cystic Fibrosis/Pulmonary Research Treatment Center, University of North Carolina, Chapel Hill, North Carolina
| | - Erica L Herzog
- 4Section of Pulmonary, Critical Care, and Sleep Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut
| | - Sumati Sundaram
- 2Department of Anesthesia, Yale University School of Medicine, New Haven, Connecticut
| | - Laura E Niklason
- 1Department of Biomedical Engineering, Yale University, New Haven, Connecticut.,2Department of Anesthesia, Yale University School of Medicine, New Haven, Connecticut
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18
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Nandkumar MA, Ashna U, Thomas LV, Nair PD. Pulmonary surfactant expression analysis—Role of cell–cell interactions and 3‐D tissue‐like architecture. Cell Biol Int 2014; 39:272-82. [DOI: 10.1002/cbin.10389] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Accepted: 07/31/2014] [Indexed: 01/24/2023]
Affiliation(s)
- Maya A. Nandkumar
- Department of Microbial TechnologyBio Medical Technology WingSree Chitra Tirunal Institute for Medical Sciences and TechnologyPoojappuraThiruvananthapuramKerala695 012India
| | - U. Ashna
- Department of Microbial TechnologyBio Medical Technology WingSree Chitra Tirunal Institute for Medical Sciences and TechnologyPoojappuraThiruvananthapuramKerala695 012India
| | - Lynda V. Thomas
- Division of Tissue Engineering and Regenerative TechnologiesBiomedical Technology WingSree Chitra Tirunal Institute for Medical Sciences and TechnologyPoojappuraThiruvananthapuramKerala695 012India
| | - Prabha D. Nair
- Division of Tissue Engineering and Regenerative TechnologiesBiomedical Technology WingSree Chitra Tirunal Institute for Medical Sciences and TechnologyPoojappuraThiruvananthapuramKerala695 012India
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19
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Reconstructing lineage hierarchies of the distal lung epithelium using single-cell RNA-seq. Nature 2014; 509:371-5. [PMID: 24739965 PMCID: PMC4145853 DOI: 10.1038/nature13173] [Citation(s) in RCA: 957] [Impact Index Per Article: 95.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Accepted: 02/19/2014] [Indexed: 01/04/2023]
Abstract
The mammalian lung is a highly branched network, in which the distal regions of the bronchial tree transform during development into a densely packed honeycomb of alveolar air sacs that mediate gas exchange. Although this transformation has been studied by marker expression analysis and fate-mapping, the mechanisms that control the progression of lung progenitors along distinct lineages into mature alveolar cell types remain obscure, in part due to the limited number of lineage markers1-3 and the effects of ensemble averaging in conventional transcriptome analysis experiments on cell populations1–5. We used microfluidic single cell RNA sequencing (RNA-seq) on 198 individual cells at 4 different stages encompassing alveolar differentiation to measure the transcriptional states which define the developmental and cellular hierarchy of the distal mouse lung epithelium. We empirically classified cells into distinct groups using an unbiased genome-wide approach that did not require a priori knowledge of the underlying cell types or prior purification of cell populations. The results confirmed the basic outlines of the classical model of epithelial cell type diversity in the distal lung and led to the discovery of many novel cell type markers and transcriptional regulators that discriminate between the different populations. We reconstructed the molecular steps during maturation of bipotential progenitors along both alveolar lineages and elucidated the full lifecycle of the alveolar type 2 cell lineage. This single cell genomics approach is applicable to any developing or mature tissue to robustly delineate molecularly distinct cell types, define progenitors and lineage hierarchies, and identify lineage-specific regulatory factors.
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20
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Johansson HM, Newman DR, Sannes PL. Whole-genome analysis of temporal gene expression during early transdifferentiation of human lung alveolar epithelial type 2 cells in vitro. PLoS One 2014; 9:e93413. [PMID: 24690998 PMCID: PMC3972118 DOI: 10.1371/journal.pone.0093413] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2013] [Accepted: 03/05/2014] [Indexed: 12/21/2022] Open
Abstract
It is generally accepted that the surfactant-producing pulmonary alveolar epithelial type II (AT2) cell acts as the progenitor of the type I (AT1) cell, but the regulatory mechanisms involved in this relationship remain the subject of active investigation. While previous studies have established a number of specific markers that are expressed during transdifferentiation from AT2 to AT1 cells, we hypothesized that additional, previously unrecognized, signaling pathways and relevant cellular functions are transcriptionally regulated at early stages of AT2 transition. In this study, a discovery-based gene expression profile analysis was undertaken of freshly isolated human AT2 (hAT2) cells grown on extracellular matrix (ECM) substrata known to either support (type I collagen) or retard (Matrigel) the early transdifferentiation process into hAT1-like cells over the first three days. Cell type-specific expression patterns analyzed by Illumina Human HT-12 BeadChip yielded over 300 genes that were up- or down-regulated. Candidate genes significantly induced or down-regulated during hAT2 transition to hAT1-like cells compared to non-transitioning hAT2 cells were identified. Major functional groups were also recognized, including those of signaling and cytoskeletal proteins as well as genes of unknown function. Expression of established signatures of hAT2 and hAT1 cells, such as surfactant proteins, caveolin-1, and channels and transporters, was confirmed. Selected novel genes further validated by qRT-PCR, protein expression analysis, and/or cellular localization included SPOCK2, PLEKHO1, SPRED1, RAB11FIP1, PTRF/CAVIN-1 and RAP1GAP. These results further demonstrate the utility of genome-wide analysis to identify relevant, novel cell type-specific signatures of early ECM-regulated alveolar epithelial transdifferentiation processes in vitro.
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Affiliation(s)
- Helena Morales Johansson
- Department of Molecular Biomedical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Donna R. Newman
- Department of Molecular Biomedical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
| | - Philip L. Sannes
- Department of Molecular Biomedical Sciences, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States of America
- * E-mail:
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21
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Rozycki HJ. Potential contribution of type I alveolar epithelial cells to chronic neonatal lung disease. Front Pediatr 2014; 2:45. [PMID: 24904906 PMCID: PMC4032902 DOI: 10.3389/fped.2014.00045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2014] [Accepted: 05/05/2014] [Indexed: 12/16/2022] Open
Abstract
The alveolar surface is covered by large flat Type I cells (alveolar epithelial cells 1, AEC1). The normal physiological function of AEC1s involves gas exchange, based on their location in approximation to the capillary endothelium and their thinness, and in ion and water flux, as shown by the presence of solute active transport proteins, water channels, and impermeable tight junctions between cells. With the recent ability to produce relatively pure cultures of AEC1 cells, new functions have been described. These may be relevant to lung injury, repair, and the abnormal development that characterizes bronchopulmonary dysplasia (BPD). To hypothesize a potential role for AEC1 in the development of lung injury and abnormal repair/development in premature lungs, evidence is presented for their presence in the developing lung, how their source may not be the Type II cell (AEC2) as has been assumed for 40 years, and how the cell can be damaged by same type of stressors as those which lead to BPD. Recent work shows that the cells are part of the innate immune response, capable of producing pro-inflammatory mediators, which could contribute to the increase in inflammation seen in early BPD. One of the receptors found exclusively on AEC1 cells in the lung, called RAGE, may also have a role in increased inflammation and alveolar simplification. While the current evidence for AEC1 involvement in BPD is circumstantial and limited at present, the accumulating data supports several hypotheses and questions regarding potential differences in the behavior of AEC1 cells from newborn and premature lung compared with the adult lung.
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Affiliation(s)
- Henry J Rozycki
- Division of Neonatal Medicine, Children's Hospital of Richmond at Virginia Commonwealth University , Richmond, VA , USA
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Establishment and evaluation of a stable cattle type II alveolar epithelial cell line. PLoS One 2013; 8:e76036. [PMID: 24086682 PMCID: PMC3784436 DOI: 10.1371/journal.pone.0076036] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2013] [Accepted: 08/25/2013] [Indexed: 12/05/2022] Open
Abstract
Macrophages and dendritic cells are recognized as key players in the defense against mycobacterial infection. Recent research has confirmed that alveolar epithelial cells (AECs) also play important roles against mycobacterium infections. Thus, establishing a stable cattle AEC line for future endogenous immune research on bacterial invasion is necessary. In the present study, we first purified and immortalized type II AECs (AEC II cells) by transfecting them with a plasmid containing the human telomerase reverse trancriptase gene. We then tested whether or not the immortalized cells retained the basic physiological properties of primary AECs by reverse-transcription polymerase chain reaction and Western blot. Finally, we tested the secretion capacity of immortalized AEC II cells upon stimulation by bacterial invasion. The cattle type II alveolar epithelial cell line (HTERT-AEC II) that we established retained lung epithelial cell characteristics: the cells were positive for surfactants A and B, and they secreted tumor necrosis factor-α and interleukin-6 in response to bacterial invasion. Thus, the cell line we established is a potential tool for research on the relationship between AECs and Mycobacterium tuberculosis.
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Davidovich N, DiPaolo BC, Lawrence GG, Chhour P, Yehya N, Margulies SS. Cyclic stretch-induced oxidative stress increases pulmonary alveolar epithelial permeability. Am J Respir Cell Mol Biol 2013; 49:156-64. [PMID: 23526210 DOI: 10.1165/rcmb.2012-0252oc] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Mechanical ventilation with high tidal volumes has been associated with pulmonary alveolar flooding. Understanding the mechanisms underlying cyclic stretch-induced increases in alveolar epithelial permeability may be important in designing preventive measures for acute lung injury. In this work, we assessed whether cyclic stretch leads to the generation of reactive oxygen species in type I-like alveolar epithelial cells, which increase monolayer permeability via activation of NF-κB and extracellular signal-regulated kinase (ERK). We cyclically stretched type I-like rat primary alveolar epithelial cells at magnitudes of 12, 25, and 37% change in surface area (ΔSA) for 10 to 120 minutes. High levels of reactive oxygen species and of superoxide and NO specifically were detected in cells stretched at 37% ΔSA for 10 to 120 minutes. Exogenous superoxide and NO stimulation increased epithelial permeability in unstretched cells, which was preventable by the NF-κB inhibitor MG132. The cyclic stretch-induced increase in permeability was decreased by the superoxide scavenger tiron and by MG132. Furthermore, tiron had a dramatic protective effect on in vivo lung permeability under mechanical ventilation conditions. Cyclic stretch increased the activation of the NF-κB signaling pathway, which was significantly decreased with the ERK inhibitor U0126. Altogether, our in vitro and in vivo data demonstrate the sensitivity of permeability to stretch- and ventilation-induced superoxide production, suggesting that using antioxidants may be helpful in the prevention and treatment of ventilator-induced lung injury.
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Affiliation(s)
- Nurit Davidovich
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104, USA
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Qian Z, Travanty EA, Oko L, Edeen K, Berglund A, Wang J, Ito Y, Holmes KV, Mason RJ. Innate immune response of human alveolar type II cells infected with severe acute respiratory syndrome-coronavirus. Am J Respir Cell Mol Biol 2013; 48:742-8. [PMID: 23418343 PMCID: PMC3727876 DOI: 10.1165/rcmb.2012-0339oc] [Citation(s) in RCA: 211] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2012] [Accepted: 11/16/2012] [Indexed: 12/14/2022] Open
Abstract
Severe acute respiratory syndrome (SARS)-coronavirus (CoV) produces a devastating primary viral pneumonia with diffuse alveolar damage and a marked increase in circulating cytokines. One of the major cell types to be infected is the alveolar type II cell. However, the innate immune response of primary human alveolar epithelial cells infected with SARS-CoV has not been defined. Our objectives included developing a culture system permissive for SARS-CoV infection in primary human type II cells and defining their innate immune response. Culturing primary human alveolar type II cells at an air-liquid interface (A/L) improved their differentiation and greatly increased their susceptibility to infection, allowing us to define their primary interferon and chemokine responses. Viral antigens were detected in the cytoplasm of infected type II cells, electron micrographs demonstrated secretory vesicles filled with virions, virus RNA concentrations increased with time, and infectious virions were released by exocytosis from the apical surface of polarized type II cells. A marked increase was evident in the mRNA concentrations of interferon-β and interferon-λ (IL-29) and in a large number of proinflammatory cytokines and chemokines. A surprising finding involved the variability of expression of angiotensin-converting enzyme-2, the SARS-CoV receptor, in type II cells from different donors. In conclusion, the cultivation of alveolar type II cells at an air-liquid interface provides primary cultures in which to study the pulmonary innate immune responses to infection with SARS-CoV, and to explore possible therapeutic approaches to modulating these innate immune responses.
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Affiliation(s)
- Zhaohui Qian
- Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado; and
| | | | - Lauren Oko
- Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Karen Edeen
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Andrew Berglund
- Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Jieru Wang
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Yoko Ito
- Department of Medicine, National Jewish Health, Denver, Colorado
| | - Kathryn V. Holmes
- Department of Microbiology, University of Colorado School of Medicine, Aurora, Colorado; and
| | - Robert J. Mason
- Department of Medicine, National Jewish Health, Denver, Colorado
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25
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Ghosh MC, Gorantla V, Makena PS, Luellen C, Sinclair SE, Schwingshackl A, Waters CM. Insulin-like growth factor-I stimulates differentiation of ATII cells to ATI-like cells through activation of Wnt5a. Am J Physiol Lung Cell Mol Physiol 2013; 305:L222-8. [PMID: 23709620 DOI: 10.1152/ajplung.00014.2013] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Alveolar type II (ATII) epithelial cells play a crucial role in the repair and remodeling of the lung following injury. ATII cells have the capability to proliferate and differentiate into alveolar type I (ATI) cells in vivo and into an ATI-like phenotype in vitro. While previous reports indicate that the differentiation of ATII cells into ATI cells is a complex biological process, the underlying mechanism responsible for differentiation is not fully understood. To investigate factors involved in this differentiation in culture, we used a PCR array and identified several genes that were either up- or downregulated in ATI-like cells (day 6 in culture) compared with day 2 ATII cells. Insulin-like growth factor-I (IGF-I) mRNA was increased nearly eightfold. We found that IGF-I was increased in the culture media of ATI-like cells and demonstrated a significant role in the differentiation process. Treatment of ATII cells with recombinant IGF-I accelerated the differentiation process, and this effect was abrogated by the IGF-I receptor blocker PQ401. We found that Wnt5a, a member of the Wnt-Frizzled pathway, was activated during IGF-I-mediated differentiation. Both protein kinase C and β-catenin were transiently activated during transdifferentiation. Knocking down Wnt5a using small-interfering RNA abrogated the differentiation process as indicated by changes in the expression of an ATII cell marker (prosurfactant protein-C). Treatment of wounded cells with either IGF-I or Wnt5a stimulated wound closure. These results suggest that IGF-I promotes differentiation of ATII to ATI cells through the activation of a noncanonical Wnt pathway.
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Affiliation(s)
- Manik C Ghosh
- Department of Physiology, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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26
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Kebaabetswe LP, Haick AK, Miura TA. Differentiated phenotypes of primary murine alveolar epithelial cells and their susceptibility to infection by respiratory viruses. Virus Res 2013; 175:110-9. [PMID: 23639425 PMCID: PMC3683362 DOI: 10.1016/j.virusres.2013.04.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2012] [Revised: 04/11/2013] [Accepted: 04/12/2013] [Indexed: 12/31/2022]
Abstract
Alveolar epithelial cells are important targets in severe respiratory viral infection. Murine ATI and ATII cultures are an in vitro model for viral pathogenesis. ATI cells are infected by IAV and MHV-1, not mouse-adapted SARS-CoV. ATII cells are infected by IAV, MHV-1, and mouse-adapted SARS-CoV. ATI and ATII cells express cytokines upon infection by respiratory viruses.
Severe respiratory viral infections are associated with spread to the alveoli of the lungs. There are multiple murine models of severe respiratory viral infections that have been used to identify viral and host factors that contribute to disease severity. Primary cultures of murine alveolar epithelial cells provide a robust in vitro model to perform mechanistic studies that can be correlated with in vivo studies to identify cell type-specific factors that contribute to pathology within the alveoli of the lung during viral infection. In this study, we established an in vitro model to compare the responses of type I (ATI) and type II (ATII) alveolar epithelial cells to infection by respiratory viruses used in murine models: mouse-adapted severe acute respiratory syndrome-associated coronavirus (SARS-CoV, v2163), murine coronavirus MHV-1, and influenza A (H1N1) virus, strain PR8. Murine alveolar cells cultured to maintain an ATII cell phenotype, determined by expression of LBP180, were susceptible to infection by all three viruses. In contrast, ATII cells that were cultured to trans-differentiate into an ATI-like cell phenotype were susceptible to MHV-1 and PR8, but not mouse-adapted SARS-CoV. Epithelial cells produce cytokines in response to viral infections, thereby activating immune responses. Thus, virus-induced cytokine expression was quantified in ATI and ATII cells. Both cell types had increased expression of IL-1β mRNA upon viral infection, though at different levels. While MHV-1 and PR8 induced expression of a number of shared cytokines in ATI cells, there were several cytokines whose expression was induced uniquely by MHV-1 infection. In summary, ATI and ATII cells exhibited differential susceptibilities and cytokine responses to infection by respiratory viruses. This in vitro model will be critical for future studies to determine the roles of these specialized cell types in the pathogenesis of respiratory viral infection.
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Affiliation(s)
| | | | - Tanya A. Miura
- Corresponding author at: 875 Perimeter Drive, MS 3051, Moscow, ID 83844-3051, USA. Tel.: +1 208 885 4940; fax: +1 208 885 7905.
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27
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Lee JH, Kim J, Gludish D, Roach RR, Saunders AH, Barrios J, Woo AJ, Chen H, Conner DA, Fujiwara Y, Stripp BR, Kim CF. Surfactant protein-C chromatin-bound green fluorescence protein reporter mice reveal heterogeneity of surfactant protein C-expressing lung cells. Am J Respir Cell Mol Biol 2013; 48. [PMID: 23204392 PMCID: PMC3604082 DOI: 10.1165/rcmb.2011-0403oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The regeneration of alveolar epithelial cells is a critical aspect of alveolar reorganization after lung injury. Although alveolar Type II (AT2) cells have been described as progenitor cells for alveolar epithelia, more remains to be understood about how their progenitor cell properties are regulated. A nuclear, chromatin-bound green fluorescence protein reporter (H2B-GFP) was driven from the murine surfactant protein-C (SPC) promoter to generate SPC H2B-GFP transgenic mice. The SPC H2B-GFP allele allowed the FACS-based enrichment and gene expression profiling of AT2 cells. Approximately 97% of AT2 cells were GFP-labeled on Postnatal Day 1, and the percentage of GFP-labeled AT2 cells decreased to approximately 63% at Postnatal Week 8. Isolated young adult SPC H2B-GFP(+) cells displayed proliferation, differentiation, and self-renewal capacity in the presence of lung fibroblasts in a Matrigel-based three-dimensional culture system. Heterogeneity within the GFP(+) population was revealed, because cells with distinct alveolar and bronchiolar gene expression arose in three-dimensional cultures. CD74, a surface marker highly enriched on GFP(+) cells, was identified as a positive selection marker, providing 3-fold enrichment for AT2 cells. In vivo, GFP expression was induced within other epithelial cell types during maturation of the distal lung. The utility of the SPC H2B-GFP murine model for the identification of AT2 cells was greatest in early postnatal lungs and more limited with age, when some discordance between SPC and GFP expression was observed. In adult mice, this allele may allow for the enrichment and future characterization of other SPC-expressing alveolar and bronchiolar cells, including putative stem/progenitor cell populations.
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Affiliation(s)
- Joo-Hyeon Lee
- Stem Cell Program and
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
- Harvard Stem Cell Institute, Cambridge, Massachusetts; and
| | - Jonghwan Kim
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
| | - David Gludish
- Stem Cell Program and
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
- Harvard Stem Cell Institute, Cambridge, Massachusetts; and
| | - Rebecca R. Roach
- Stem Cell Program and
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
- Harvard Stem Cell Institute, Cambridge, Massachusetts; and
| | - Arven H. Saunders
- Stem Cell Program and
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
- Harvard Stem Cell Institute, Cambridge, Massachusetts; and
| | - Juliana Barrios
- Stem Cell Program and
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
- Harvard Stem Cell Institute, Cambridge, Massachusetts; and
| | - Andrew Jonghan Woo
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
| | - Huaiyong Chen
- Department of Medicine and Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
| | - David A. Conner
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Yuko Fujiwara
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
| | - Barry R. Stripp
- Department of Medicine and Department of Cell Biology, Duke University Medical Center, Durham, North Carolina
| | - Carla F. Kim
- Stem Cell Program and
- Division of Hematology/Oncology, Boston Children’s Hospital, Boston, Massachusetts
- Department of Genetics, Harvard Medical School, Boston, Massachusetts
- Harvard Stem Cell Institute, Cambridge, Massachusetts; and
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Wong MH, Johnson MD. Differential response of primary alveolar type I and type II cells to LPS stimulation. PLoS One 2013; 8:e55545. [PMID: 23383221 PMCID: PMC3561226 DOI: 10.1371/journal.pone.0055545] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2012] [Accepted: 12/30/2012] [Indexed: 12/31/2022] Open
Abstract
The alveolar epithelium serves as a barrier between organism and environment and functions as the first line of protection against potential respiratory pathogens. Alveolar type II (TII) cells have traditionally been considered the immune cells of the alveolar epithelium, as they possess immunomodulatory functions; however, the precise role of alveolar type I (TI) cells, which comprise ∼95% of the alveolar epithelial surface area, in lung immunity is not clear. We sought to determine if there was a difference in the response of TI and TII cells to lung injury and if TI cells could actively participate in the alveolar immune response. TI cells isolated via fluorescence activated cell sorting (FACS) from LPS-injured rats demonstrated greater fold-induction of multiple inflammatory mediators than TII cells isolated in the same manner from the same animals. Levels of the cytokines TNF-α, IL-6 and IL-1β from cultured primary rat TI cells after LPS stimulation were significantly increased compared to similarly studied primary rat TII cells. We found that contrary to published reports, cultured TII cells produce relatively small amounts of TNF-α, IL-6 and IL-1β after LPS treatment; the higher levels of cytokine expression from cultured TII cells reported in the literature were likely from macrophage contamination due to traditional non-FACS TII cell isolation methods. Co-culture of TII cells with macrophages prior to LPS stimulation increased TNF-α and IL-6 production to levels reported by other investigators for TII cells, however, co-culture of TI cells and macrophages prior to LPS treatment resulted in marked increases in TNF-α and IL-6 production. Finally, exogenous surfactant blunted the IL-6 response to LPS in cultured TI cells. Taken together, these findings advocate a role for TI cells in the innate immune response and suggest that both TI and TII cells are active players in host defense mechanisms in the lung.
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Affiliation(s)
- Mandi H. Wong
- San Francisco Veterans Affairs Medical Center, San Francisco, California, United States of America
- Northern California Institute for Research and Education, San Francisco, California, United States of America
| | - Meshell D. Johnson
- San Francisco Veterans Affairs Medical Center, San Francisco, California, United States of America
- Northern California Institute for Research and Education, San Francisco, California, United States of America
- Department of Medicine, University of California San Francisco, San Francisco, California, United States of America
- * E-mail:
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Wu CJ, Huang WC, Chen LC, Shen CR, Kuo ML. Pseudotyped adeno-associated virus 2/9-delivered CCL11 shRNA alleviates lung inflammation in an allergen-sensitized mouse model. Hum Gene Ther 2012; 23:1156-65. [PMID: 22913580 DOI: 10.1089/hum.2012.012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Airway infiltration by eosinophils is a major characteristic of chronic asthma. CCL11 (eotaxin-1) is secreted by lung epithelial cells and functions as the major chemokine for eosinophil recruitment. Pseudotyped adeno-associated virus (AAV) 2/9, composed by the AAV2 rep and AAV9 cap genes, can efficiently target lung epithelial cells and might carry gene sequences with therapeutic potential for asthma. This study aimed to determine whether pseudotyped AAV2/9 virus carrying the small hairpin RNA targeting CCL11 and expressed by CMV/U6 promoter could reduce eosinophilia and asthmatic responses in mite allergen-sensitized mice. Mice were sensitized by intraperitoneal and challenged by intratracheal injection with recombinant Dermatophagoides pteronyssinus group 2 allergen (rDp2). AAV2/9 viral vectors were intratracheally injected three days before the first challenge. AAV2/9 sh47 virus significantly reduced airway hyperresponsiveness, airway resistance, CCL11 levels, and eosinophilia in the lungs of sensitized mice. Th2 cytokines, including interleukins (IL)-4, IL-5, and IL-10, were also significantly reduced in the bronchoalveolar lavage fluid of AAV2/9 sh47 virus-treated mice. Th2 cytokine levels were also reduced in rDp2-stimulated mediastinal lymphocytes in treated mice. However, serum levels of rDp2-specific IgG1 and IgE, as well as Th2 cytokine levels in rDp2-stimulated splenocyte culture supernatants, were comparable to the sensitized control group. The results suggest that AAV2/9 sh47 virus relieved local instead of systemic inflammatory responses. Therefore, the CMV/U6 promoter with AAV2/9 viral vector, which is preferable to target lung epithelia cells, might be applied as a novel therapeutic approach for asthma.
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Affiliation(s)
- Chia-Jen Wu
- Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Taoyuan, Taiwan
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Kosmider B, Messier EM, Janssen WJ, Nahreini P, Wang J, Hartshorn KL, Mason RJ. Nrf2 protects human alveolar epithelial cells against injury induced by influenza A virus. Respir Res 2012; 13:43. [PMID: 22672594 PMCID: PMC3520784 DOI: 10.1186/1465-9921-13-43] [Citation(s) in RCA: 120] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 05/16/2012] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Influenza A virus (IAV) infection primarily targets respiratory epithelial cells and produces clinical outcomes ranging from mild upper respiratory infection to severe pneumonia. Recent studies have shown the importance of lung antioxidant defense systems against injury by IAV. Nuclear factor-erythroid 2 related factor 2 (Nrf2) activates the majority of antioxidant genes. METHODS Alveolar type II (ATII) cells and alveolar macrophages (AM) were isolated from human lungs not suitable for transplantation and donated for medical research. In some studies ATII cells were transdifferentiated to alveolar type I-like (ATI-like) cells. Alveolar epithelial cells were infected with A/PR/8/34 (PR8) virus. We analyzed PR8 virus production, influenza A nucleoprotein levels, ROS generation and expression of antiviral genes. Immunocytofluorescence was used to determine Nrf2 translocation and western blotting to detect Nrf2, HO-1 and caspase 1 and 3 cleavage. We also analyzed ingestion of PR8 virus infected apoptotic ATII cells by AM, cytokine levels by ELISA, glutathione levels, necrosis and apoptosis by TUNEL assay. Moreover, we determined the critical importance of Nrf2 using adenovirus Nrf2 (AdNrf2) or Nrf2 siRNA to overexpress or knockdown Nrf2, respectively. RESULTS We found that IAV induced oxidative stress, cytotoxicity and apoptosis in ATI-like and ATII cells. We also found that AM can ingest PR8 virus-induced apoptotic ATII cells (efferocytosis) but not viable cells, whereas ATII cells did not ingest these apoptotic cells. PR8 virus increased ROS production, Nrf2, HO-1, Mx1 and OAS1 expression and Nrf2 translocation to the nucleus. Nrf2 knockdown with siRNA sensitized ATI-like cells and ATII cells to injury induced by IAV and overexpression of Nrf2 with AdNrf2 protected these cells. Furthermore, Nrf2 overexpression followed by infection with PR8 virus decreased virus replication, influenza A nucleoprotein expression, antiviral response and oxidative stress. However, AdNrf2 did not increase IFN-λ1 (IL-29) levels. CONCLUSIONS Our results indicate that IAV induces alveolar epithelial injury and that Nrf2 protects these cells from the cytopathic effects of IAV likely by increasing the expression of antioxidant genes. Identifying the pathways involved in protecting cells from injury during influenza infection may be particularly important for developing new therapeutic strategies.
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Affiliation(s)
- Beata Kosmider
- Department of Medicine, National Jewish Health, 1400 Jackson Street, Denver, CO 80206, USA.
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Hobi N, Ravasio A, Haller T. Interfacial stress affects rat alveolar type II cell signaling and gene expression. Am J Physiol Lung Cell Mol Physiol 2012; 303:L117-29. [PMID: 22610352 DOI: 10.1152/ajplung.00340.2011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Previous work from our group (Ravasio A, Hobi N, Bertocchi C, Jesacher A, Dietl P, Haller T. Am J Physiol Cell Physiol 300: C1456-C1465, 2011.) showed that contact of alveolar epithelial type II cells with an air-liquid interface (I(AL)) leads to a paradoxical situation. It is a potential threat that can cause cell injury, but also a Ca(2+)-dependent stimulus for surfactant secretion. Both events can be explained by the impact of interfacial tensile forces on cellular structures. Here, the strength of this mechanical stimulus became also apparent in microarray studies by a rapid and significant change on the transcriptional level. Cells challenged with an I(AL) in two different ways showed activation/inactivation of cellular pathways involved in stress response and defense, and a detailed Pubmatrix search identified genes associated with several lung diseases and injuries. Altogether, they suggest a close relationship of interfacial stress sensation with current models in alveolar micromechanics. Further similarities between I(AL) and cell stretch were found with respect to the underlying signaling events. The source of Ca(2+) was extracellular, and the transmembrane Ca(2+) entry pathway suggests the involvement of a mechanosensitive channel. We conclude that alveolar type II cells, due to their location and morphology, are specific sensors of the I(AL), but largely protected from interfacial stress by surfactant release.
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Affiliation(s)
- Nina Hobi
- Department of Physiology and Medical Physics, Division of Physiology, Innsbruck Medical University, Austria
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32
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Ion transport by pulmonary epithelia. J Biomed Biotechnol 2011; 2011:174306. [PMID: 22131798 PMCID: PMC3205707 DOI: 10.1155/2011/174306] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2011] [Accepted: 08/16/2011] [Indexed: 12/13/2022] Open
Abstract
The lung surface of air-breathing vertebrates is formed by a continuous epithelium that is covered by a fluid layer. In the airways, this epithelium is largely pseudostratified consisting of diverse cell types such as ciliated cells, goblet cells, and undifferentiated basal cells, whereas the alveolar epithelium consists of alveolar type I and alveolar type II cells. Regulation and maintenance of the volume and viscosity of the fluid layer covering the epithelium is one of the most important functions of the epithelial barrier that forms the outer surface area of the lungs. Therefore, the epithelial cells are equipped with a wide variety of ion transport proteins, among which Na+, Cl−, and K+ channels have been identified to play a role in the regulation of the fluid layer. Malfunctions of pulmonary epithelial ion transport processes and, thus, impairment of the liquid balance in our lungs is associated with severe diseases, such as cystic fibrosis and pulmonary oedema. Due to the important role of pulmonary epithelial ion transport processes for proper lung function, the present paper summarizes the recent findings about composition, function, and ion transport properties of the airway epithelium as well as of the alveolar epithelium.
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Wilkinson WJ, Benjamin AR, De Proost I, Orogo-Wenn MC, Yamazaki Y, Staub O, Morita T, Adriaensen D, Riccardi D, Walters DV, Kemp PJ. Alveolar epithelial CNGA1 channels mediate cGMP-stimulated, amiloride-insensitive, lung liquid absorption. Pflugers Arch 2011; 462:267-79. [PMID: 21559843 DOI: 10.1007/s00424-011-0971-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Revised: 04/21/2011] [Accepted: 04/22/2011] [Indexed: 11/25/2022]
Abstract
Impairment of lung liquid absorption can lead to severe respiratory symptoms, such as those observed in pulmonary oedema. In the adult lung, liquid absorption is driven by cation transport through two pathways: a well-established amiloride-sensitive Na(+) channel (ENaC) and, more controversially, an amiloride-insensitive channel that may belong to the cyclic nucleotide-gated (CNG) channel family. Here, we show robust CNGA1 (but not CNGA2 or CNGA3) channel expression principally in rat alveolar type I cells; CNGA3 was expressed in ciliated airway epithelial cells. Using a rat in situ lung liquid clearance assay, CNG channel activation with 1 mM 8Br-cGMP resulted in an approximate 1.8-fold stimulation of lung liquid absorption. There was no stimulation by 8Br-cGMP when applied in the presence of either 100 μM L: -cis-diltiazem or 100 nM pseudechetoxin (PsTx), a specific inhibitor of CNGA1 channels. Channel specificity of PsTx and amiloride was confirmed by patch clamp experiments showing that CNGA1 channels in HEK 293 cells were not inhibited by 100 μM amiloride and that recombinant αβγ-ENaC were not inhibited by 100 nM PsTx. Importantly, 8Br-cGMP stimulated lung liquid absorption in situ, even in the presence of 50 μM amiloride. Furthermore, neither L: -cis-diltiazem nor PsTx affected the β(2)-adrenoceptor agonist-stimulated lung liquid absorption, but, as expected, amiloride completely ablated it. Thus, transport through alveolar CNGA1 channels, located in type I cells, underlies the amiloride-insensitive component of lung liquid reabsorption. Furthermore, our in situ data highlight the potential of CNGA1 as a novel therapeutic target for the treatment of diseases characterised by lung liquid overload.
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Affiliation(s)
- William J Wilkinson
- Division of Pathophysiology and Repair, School of Biosciences, Cardiff University, Museum Avenue, Cardiff, UK
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Mitchell LA, Overgaard CE, Ward C, Margulies SS, Koval M. Differential effects of claudin-3 and claudin-4 on alveolar epithelial barrier function. Am J Physiol Lung Cell Mol Physiol 2011; 301:L40-9. [PMID: 21515662 DOI: 10.1152/ajplung.00299.2010] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Alveolar barrier function depends critically on the claudin family tight junction proteins. Of the major claudins expressed by alveolar epithelial cells, claudin (Cldn)-3 and Cldn-4 are the most closely related by amino acid homology, yet they differ dramatically in the pattern of expression. Previously published reports have shown that Cldn-3 is predominantly expressed by type II alveolar epithelial cells; Cldn-4 is expressed throughout the alveolar epithelium and is specifically upregulated in response to acute lung injury. Using primary rat alveolar epithelial cells transduced with yellow fluorescent protein-tagged claudin constructs, we have identified roles for Cldn-3 and Cldn-4 in alveolar epithelial barrier function. Surprisingly, increasing expression of Cldn-3 decreased alveolar epithelial barrier function, as assessed by transepithelial resistance and dye flux measurements. Conversely, increasing Cldn-4 expression improved alveolar epithelial transepithelial resistance compared with control cells. Other alveolar epithelial tight junction proteins were largely unaffected by increased expression of Cldn-3 and Cldn-4. Taken together, these results demonstrate that, in the context of the alveolar epithelium, Cldn-3 and Cldn-4 have different effects on paracellular permeability, despite significant homology in their extracellular loop domains.
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Affiliation(s)
- Leslie A Mitchell
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Emory University, Atlanta, Georgia 30322, USA
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Mishra A, Chintagari NR, Guo Y, Weng T, Su L, Liu L. Purinergic P2X7 receptor regulates lung surfactant secretion in a paracrine manner. J Cell Sci 2011; 124:657-68. [PMID: 21266468 DOI: 10.1242/jcs.066977] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Alveolar epithelium is composed of alveolar epithelial cells of type I (AEC I) and type II (AEC II). AEC II secrete lung surfactant by means of exocytosis. P2X(7) receptor (P2X(7)R), a P2 purinergic receptor, has been implicated in the regulation of synaptic transmission and inflammation. Here, we report that P2X(7)R, which is expressed in AEC I but not AEC II, is a novel mediator for the paracrine regulation of surfactant secretion in AEC II. In primary co-cultures of AEC I and AEC II benzoyl ATP (BzATP; an agonist of P2X(7)R) increased surfactant secretion, which was blocked by the P2X(7)R antagonist Brilliant Blue G. This effect was observed in AEC II co-cultured with human embryonic kidney HEK-293 cells stably expressing rat P2X(7)R, but not when co-cultured with AEC I in which P2X(7)R was knocked down or in co-cultures of AEC I and AEC II isolated from P2X(7)R(-/-) mice. BzATP-mediated secretion involved P2Y(2) receptor signaling because it was reduced by the addition of the ATP scavengers apyrase and adenosine deaminase and the P2Y(2) receptor antagonist suramin. However, the stimulation with BzATP might also release other substances that potentially increase surfactant secretion as a greater stimulation of secretion was observed in AEC II incubated with BzATP when co-cultured with E10 or HEK-293-P2X(7)R cells than with ATP alone. P2X(7)R(-/-) mice failed to increase surfactant secretion in response to hyperventilation, pointing to the physiological relevance of P2X(7)R in maintaining surfactant homeostasis in the lung. These results suggest that the activation of P2X(7)R increases surfactant secretion by releasing ATP from AEC I and subsequently stimulating P2Y(2) receptors in AEC II.
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Affiliation(s)
- Amarjit Mishra
- Lundberg-Kienlen Lung Biology and Toxicology Laboratory, Department of Physiological Sciences, Oklahoma State University, Stillwater, OK 74078, USA
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Godin LM, Vergen J, Prakash YS, Pagano RE, Hubmayr RD. Spatiotemporal dynamics of actin remodeling and endomembrane trafficking in alveolar epithelial type I cell wound healing. Am J Physiol Lung Cell Mol Physiol 2011; 300:L615-23. [PMID: 21216977 DOI: 10.1152/ajplung.00265.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Alveolar epithelial type I cell (ATI) wounding is prevalent in ventilator-injured lungs and likely contributes to pathogenesis of "barotrauma" and "biotrauma." In experimental models most wounded alveolar cells repair plasma membrane (PM) defects and survive insults. Considering the force balance between edge energy at the PM wound margins and adhesive interactions of the lipid bilayer with the underlying cytoskeleton (CSK), we tested the hypothesis that subcortical actin depolymerization is a key facilitator of PM repair. Using real-time fluorescence imaging of primary rat ATI transfected with a live cell actin-green fluorescent protein construct (Lifeact-GFP) and loaded with N-rhodamine phosphatidylethanolamine (PE), we examined the spatial and temporal coordination between cytoskeletal remodeling and PM repair following micropuncture. Membrane integrity was inferred from the fluorescence intensity profiles of the cytosolic label calcein AM. Wounding led to rapid depolymerization of the actin CSK near the wound site, concurrent with accumulation of endomembrane-derived N-rhodamine PE. Both responses were sustained until PM integrity was reestablished, which typically occurs between ∼10 and 40 s after micropuncture. Only thereafter did the actin CSK near the wound begin to repolymerize, while the rate of endomembrane lipid accumulation decreased. Between 60 and 90 s after successful PM repair, after translocation of the actin nucleation factor cortactin, a dense actin fiber network formed. In cells that did not survive micropuncture injury, actin remodeling did not occur. These novel results highlight the importance of actin remodeling in ATI cell repair and suggest molecular targets for modulating the repair process.
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Affiliation(s)
- Lindsay M Godin
- Department of Physiology and Biomedical Engineering, Mayo Clinic, Rochester, Minnesota, USA
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Takano M, Ryoko Y. Transport of Proteins and Peptides and its Regulation in Alveolar Epithelial Cells. ACTA ACUST UNITED AC 2011. [DOI: 10.5360/membrane.36.145] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Eisenberg JL, Safi A, Wei X, Espinosa HD, Budinger GS, Takawira D, Hopkinson SB, Jones JC. Substrate stiffness regulates extracellular matrix deposition by alveolar epithelial cells. ACTA ACUST UNITED AC 2011. [PMID: 23204878 DOI: 10.2147/rrb.s13178] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
AIM: The aim of the study was to address whether a stiff substrate, a model for pulmonary fibrosis, is responsible for inducing changes in the phenotype of alveolar epithelial cells (AEC) in the lung, including their deposition and organization of extracellular matrix (ECM) proteins. METHODS: Freshly isolated lung AEC from male Sprague Dawley rats were seeded onto polyacrylamide gel substrates of varying stiffness and analyzed for expression and organization of adhesion, cytoskeletal, differentiation, and ECM components by Western immunoblotting and confocal immunofluorescence microscopy. RESULTS: We observed that substrate stiffness influences cell morphology and the organization of focal adhesions and the actin cytoskeleton. Surprisingly, however, we found that substrate stiffness has no influence on the differentiation of type II into type I AEC, nor does increased substrate stiffness lead to an epithelial-mesenchymal transition. In contrast, our data indicate that substrate stiffness regulates the expression of the α3 laminin subunit by AEC and the organization of both fibronectin and laminin in their ECM. CONCLUSIONS: An increase in substrate stiffness leads to enhanced laminin and fibronectin assembly into fibrils, which likely contributes to the disease phenotype in the fibrotic lung.
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Affiliation(s)
- Jessica L Eisenberg
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA ; Division of Pulmonary Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Koval M. Keratinocyte growth factor improves alveolar barrier function: keeping claudins in line. Am J Physiol Lung Cell Mol Physiol 2010; 299:L721-3. [PMID: 20952495 DOI: 10.1152/ajplung.00365.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Gonzalez RF, Allen L, Gonzales L, Ballard PL, Dobbs LG. HTII-280, a biomarker specific to the apical plasma membrane of human lung alveolar type II cells. J Histochem Cytochem 2010; 58:891-901. [PMID: 20566753 PMCID: PMC2942742 DOI: 10.1369/jhc.2010.956433] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2010] [Accepted: 06/10/2010] [Indexed: 11/22/2022] Open
Abstract
The pulmonary alveolar epithelium is composed of two morphologically distinct cell types, type I (TI) and type II (TII) cells. Alveolar TII cells synthesize, secrete, and recycle surfactant components; contain ion transporters; and secrete immune effector molecules. In response to alveolar injury, TII cells have the capacity to act as progenitor cells, proliferating and transdifferentiating into TI cells. Although various proteins are associated with TII cells, a plasma membrane marker specific to human TII cells that would be useful for identification in tissue and for isolating this cell type has not been described previously. We devised a strategy to produce a monoclonal antibody (MAb) specific to the apical surface of human TII cells and developed an MAb that appears to be specific for human TII cells. The antibody recognizes a 280- to 300-kDa protein, HTII-280, which has the biochemical characteristics of an integral membrane protein. HTII-280 is detected by week 11 of gestation and is developmentally regulated. HTII-280 is useful for isolating human TII cells with purities and viabilities >95%. HTII-280 is likely to be a useful morphological and biochemical marker of human TII cells that may help to advance our understanding of various lung pathological conditions, including the origin and development of various lung tumors.
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Affiliation(s)
- Robert F Gonzalez
- Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA 94118, USA
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LaFemina MJ, Rokkam D, Chandrasena A, Pan J, Bajaj A, Johnson M, Frank JA. Keratinocyte growth factor enhances barrier function without altering claudin expression in primary alveolar epithelial cells. Am J Physiol Lung Cell Mol Physiol 2010; 299:L724-34. [PMID: 20833776 DOI: 10.1152/ajplung.00233.2010] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Keratinocyte growth factor (KGF) has efficacy in several experimental models of lung injury; however, the mechanisms underlying KGF's protective effect remain incompletely understood. This study was undertaken to determine whether KGF augments barrier function in primary rat alveolar epithelial cells grown in culture, specifically whether KGF alters tight junction function via claudin expression. KGF significantly increased alveolar epithelial barrier function in culture as assessed by transepithelial electrical resistance (TER) and paracellular permeability. Fluorescence-activated cell sorting of freshly isolated type 1 (AT1) and type 2 (AT2) cells followed by quantitative real-time RT-PCR revealed that more than 97% of claudin mRNA transcripts in these cells were for claudins-3, -4, and -18. Using cultured AT2 cells, we then examined the effect of KGF on the protein levels of the claudins with the highest mRNA levels: -3, -4, -5, -7, -12, -15, and -18. KGF did not alter the levels of any of the claudins tested, nor of zona occludens-1 (ZO-1) or occludin. Moreover, localization of claudins-3, -4, -18, and ZO-1 was unchanged. KGF did induce a marked increase in the apical perijunctional F-actin ring. Actin depolymerization with cytochalasin D blocked the KGF-mediated increase in TER without significantly changing TER in control cells. Together, these data support a novel mechanism by which KGF enhances alveolar barrier function, modulation of the actin cytoskeleton. In addition, these data demonstrate the complete claudin expression profile for AT1 and AT2 cells and indicate that claudins-3, -4, and -18 are the primary claudins expressed in these cell types.
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Wang S, Hubmayr RD. Type I alveolar epithelial phenotype in primary culture. Am J Respir Cell Mol Biol 2010; 44:692-9. [PMID: 20616357 DOI: 10.1165/rcmb.2009-0359oc] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Type I alveolar epithelial cells (ATIs) are very large, thin cells, which extend across several air sacs and cover more than 95% of the alveolar surface area. ATIs are the target of many insults, including ventilator-induced lung injury, and are generally considered terminally differentiated cells arising from type II cell (ATII) lineage. ATIs have proven difficult to harvest and maintain in primary culture, which is why much of ATI biology has been inferred from studies on ex vivo, ATII-derived, so-called ATI-like cells. We report on a modified approach to rat ATI harvest and primary culture, which yielded the following observations: (1) rat ATI can be harvested and maintained with a high degree of purity in primary culture; (2) in vitro growth characteristics of primary ATIs differ from those of ATII-derived ATI-like cells; ATIs, but not ex vivo, ATII-derived ATI-like cells, are capable of cell division; (3) ATIs readily repair plasma membrane wounds without the subsequent loss of their ability to divide; (4) ATI monolayers heal scratch wounds primarily by cell spreading and migration. Although the ability of ATIs to divide may be limited to the in vitro environment, we do believe that their role in alveolar wound repair deserves to be revisited, and the molecular control of ATI-ATII plasticity further explored.
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Affiliation(s)
- Shaohua Wang
- Thoracic Diseases Research Unit, Division of Pulmonary and Critical Care Medicine, Department of Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Ballard PL, Lee JW, Fang X, Chapin C, Allen L, Segal MR, Fischer H, Illek B, Gonzales LW, Kolla V, Matthay MA. Regulated gene expression in cultured type II cells of adult human lung. Am J Physiol Lung Cell Mol Physiol 2010; 299:L36-50. [PMID: 20382749 DOI: 10.1152/ajplung.00427.2009] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Alveolar type II cells have multiple functions, including surfactant production and fluid clearance, which are critical for lung function. Differentiation of type II cells occurs in cultured fetal lung epithelial cells treated with dexamethasone plus cAMP and isobutylmethylxanthine (DCI) and involves increased expression of 388 genes. In this study, type II cells of human adult lung were isolated at approximately 95% purity, and gene expression was determined (Affymetrix) before and after culturing 5 days on collagen-coated dishes with or without DCI for the final 3 days. In freshly isolated cells, highly expressed genes included SFTPA/B/C, SCGB1A, IL8, CXCL2, and SFN in addition to ubiquitously expressed genes. Transcript abundance was correlated between fetal and adult cells (r = 0.88), with a subset of 187 genes primarily related to inflammation and immunity that were expressed >10-fold higher in adult cells. During control culture, expression increased for 8.1% of expressed genes and decreased for approximately 4% including 118 immune response and 10 surfactant-related genes. DCI treatment promoted lamellar body production and increased expression of approximately 3% of probed genes by > or =1.5-fold; 40% of these were also induced in fetal cells. Highly induced genes (> or =10-fold) included PGC, ZBTB16, DUOX1, PLUNC, CIT, and CRTAC1. Twenty-five induced genes, including six genes related to surfactant (SFTPA/B/C, PGC, CEBPD, and ADFP), also had decreased expression during control culture and thus are candidates for hormonal regulation in vivo. Our results further define the adult human type II cell molecular phenotype and demonstrate that a subset of genes remains hormone responsive in cultured adult cells.
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Affiliation(s)
- Philip L Ballard
- Department of Pediatrics, University of California San Francisco, San Francisco, USA.
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Flozak AS, Lam AP, Russell S, Jain M, Peled ON, Sheppard KA, Beri R, Mutlu GM, Budinger GRS, Gottardi CJ. Beta-catenin/T-cell factor signaling is activated during lung injury and promotes the survival and migration of alveolar epithelial cells. J Biol Chem 2009; 285:3157-67. [PMID: 19933277 DOI: 10.1074/jbc.m109.070326] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The Wnt/beta-catenin signaling cascade activates genes that allow cells to adopt particular identities throughout development. In adult self-renewing tissues like intestine and blood, activation of the Wnt pathway maintains a progenitor phenotype, whereas forced inhibition of this pathway promotes differentiation. In the lung alveolus, type 2 epithelial cells (AT2) have been described as progenitors for the type 1 cell (AT1), but whether AT2 progenitors use the same signaling mechanisms to control differentiation as rapidly renewing tissues is not known. We show that adult AT2 cells do not exhibit constitutive beta-catenin signaling in vivo, using the AXIN2(+/LacZ) reporter mouse, or after fresh isolation of an enriched population of AT2 cells. Rather, this pathway is activated in lungs subjected to bleomycin-induced injury, as well as upon placement of AT2 cells in culture. Forced inhibition of beta-catenin/T-cell factor signaling in AT2 cultures leads to increased cell death. Cells that survive show reduced migration after wounding and reduced expression of AT1 cell markers (T1alpha and RAGE). These results suggest that AT2 cells may function as facultative progenitors, where activation of Wnt/beta-catenin signaling during lung injury promotes alveolar epithelial survival, migration, and differentiation toward an AT1-like phenotype.
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Affiliation(s)
- Annette S Flozak
- Department of Medicine, Division of Pulmonary and Critical Care, Northwestern University Feinberg School of Medicine, Chicago, Illinois 60611, USA
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Abstract
The human lung produces considerable amounts of H(2)O(2). In the normal uninflamed epithelium of both the airways and the alveoli, mucosal release of H(2)O(2) is readily detected both in cell cultures in vitro and in the exhaled breath of humans. The dual oxidases DUOX1 and DUOX2 are the H(2)O(2)-producing isoforms of the NADPH oxidase family found in epithelial cells. The DUOXs are prominently expressed at the apical cell pole of ciliated cells in the airways and in type II cells of the alveoli. Recent studies focused on the functional consequences of H(2)O(2) release by DUOX into the lung lining fluid. In the airways, a major function of DUOX is to support lactoperoxidase (LPO) to generate bactericidal OSCN(-), and there are indications that the DUOX/LPO defense system is critically dependent on the function of the CFTR Cl(-) channel, which provides both SCN(-) (for LPO function) and HCO(3)(-) (for pH adjustment) to the airway surface liquid. Although DUOX is also functional in the alveolar epithelium, no comparable heme peroxidase is present in the alveolus, and thus DUOX-mediated H(2)O(2) release by alveolar cells may have other functions, such as cellular signaling.
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Affiliation(s)
- Horst Fischer
- Children's Hospital Oakland Research Institute, Oakland, California 94609, USA.
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Eaton DC, Helms MN, Koval M, Bao HF, Jain L. The contribution of epithelial sodium channels to alveolar function in health and disease. Annu Rev Physiol 2009; 71:403-23. [PMID: 18831683 DOI: 10.1146/annurev.physiol.010908.163250] [Citation(s) in RCA: 139] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Amiloride-sensitive epithelial sodium channels (ENaC) play an important role in lung sodium transport. Sodium transport is closely regulated to maintain an appropriate fluid layer on the alveolar surface. Both alveolar type I and II cells have several different sodium-permeable channels in their apical membranes that play a role in normal lung physiology and pathophysiology. In many epithelial tissues, ENaC is formed from three subunit proteins: alpha, beta, and gamma ENaC. Part of the diversity of sodium-permeable channels in lung arises from assembling different combinations of these subunits to form channels with different biophysical properties and different mechanisms for regulation. Thus, lung epithelium has enormous flexibility to alter the magnitude of salt and water transport. In lung, ENaC is regulated by many transmitter and hormonal agents. Regulation depends upon the type of sodium channel but involves controlling the number of apical channels and/or the activity of individual channels.
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Affiliation(s)
- Douglas C Eaton
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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Flodby P, Borok Z, Banfalvi A, Zhou B, Gao D, Minoo P, Ann DK, Morrisey EE, Crandall ED. Directed expression of Cre in alveolar epithelial type 1 cells. Am J Respir Cell Mol Biol 2009; 43:173-8. [PMID: 19767448 DOI: 10.1165/rcmb.2009-0226oc] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Pulmonary alveolar epithelium is comprised of two morphologically and functionally distinct cell types, alveolar epithelial type (AT) I and AT2 cells. Genetically modified mice with cell-specific Cre/loxP-mediated knockouts of relevant genes in each respective cell type would be useful to help elucidate the relative contributions of AT1 versus AT2 cells to alveolar homeostasis. Cre has previously been efficiently expressed in AT2 cells in mouse lung with the surfactant protein (SP)-C promoter; however, no transgenic mouse expressing Cre in AT1 cells has so far been available. To develop an AT1 cell-specific transgenic Cre mouse, we generated a knockin of a Cre-IRES-DsRed cassette into exon 1 of the endogenous aquaporin 5 (Aqp5) gene, a gene expressed specifically in AT1 cells in the distal lung epithelium, resulting in the mouse line, Aqp5-Cre-IRES-DsRed (ACID). Endogenous Aqp5 and transgenic Cre in ACID mice showed a very similar pattern of tissue distribution by RT-PCR. To analyze Cre activity, ACID was crossed to two Cre reporter strains, R26LacZ and mT/mG. Double-transgenic offspring demonstrated reporter gene expression in a very high fraction of AT1 cells in the distal lung, whereas AT2 cells were negative. As expected, variable reporter expression was detected in several other tissues where endogenous Aqp5 is expressed (e.g., submandibular salivary gland and stomach). ACID mice should be of major utility in analyzing the functional contribution of AT1 cells to alveolar epithelial properties in vivo with Cre/loxP-mediated gene deletion technology.
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Affiliation(s)
- Per Flodby
- Will Rogers Institute Pulmonary Research Center, Department of Medicine, University of Southern California, Los Angeles, USA.
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Gonzalez RF, Allen L, Dobbs LG. Rat alveolar type I cells proliferate, express OCT-4, and exhibit phenotypic plasticity in vitro. Am J Physiol Lung Cell Mol Physiol 2009; 297:L1045-55. [PMID: 19717550 DOI: 10.1152/ajplung.90389.2008] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Alveolar type I (TI) cells are large, squamous cells that cover 95-99% of the internal surface area of the lung. Although TI cells are believed to be terminally differentiated, incapable of either proliferation or phenotypic plasticity, TI cells in vitro both proliferate and express phenotypic markers of other differentiated cell types. Rat TI cells isolated in purities of >99% proliferate in culture, with a sixfold increase in cell number before the cells reach confluence; >50% of the cultured TI cells are Ki67+. At cell densities of 1-2 cells/well, approximately 50% of the cells had the capacity to form colonies. Under the same conditions, type II cells do not proliferate. Cultured TI cells express RTI40 and aquaporin 5, phenotypic markers of the TI cell phenotype. By immunofluorescence, Western blotting, and Q-PCR, TI cells express OCT-4A (POU5F1), a transcription factor associated with maintenance of the pluripotent state in stem cells. Based on the expression patterns of various marker proteins, TI cells are distinct from either of two recently described putative pulmonary multipotent cell populations, the bronchoalveolar stem cell or the OCT-4+ stem/progenitor cell. Although TI cells in adult rat lung tissue do not express either surfactant protein C (SP-C) or CC10, respective markers of the TII and Clara cell phenotypes, in culture TI cells can be induced to express both SP-C and CC10. Together, the findings that TI cells proliferate and exhibit phenotypic plasticity in vitro raise the possibility that TI cells may have similar properties in vivo.
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Affiliation(s)
- Robert F Gonzalez
- Cardiovascular Research Institute, University of California San Francisco, 94118, USA
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Howard BE, Sick B, Heber S. Unsupervised assessment of microarray data quality using a Gaussian mixture model. BMC Bioinformatics 2009; 10:191. [PMID: 19545436 PMCID: PMC2717951 DOI: 10.1186/1471-2105-10-191] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2008] [Accepted: 06/22/2009] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Quality assessment of microarray data is an important and often challenging aspect of gene expression analysis. This task frequently involves the examination of a variety of summary statistics and diagnostic plots. The interpretation of these diagnostics is often subjective, and generally requires careful expert scrutiny. RESULTS We show how an unsupervised classification technique based on the Expectation-Maximization (EM) algorithm and the naïve Bayes model can be used to automate microarray quality assessment. The method is flexible and can be easily adapted to accommodate alternate quality statistics and platforms. We evaluate our approach using Affymetrix 3' gene expression and exon arrays and compare the performance of this method to a similar supervised approach. CONCLUSION This research illustrates the efficacy of an unsupervised classification approach for the purpose of automated microarray data quality assessment. Since our approach requires only unannotated training data, it is easy to customize and to keep up-to-date as technology evolves. In contrast to other "black box" classification systems, this method also allows for intuitive explanations.
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Affiliation(s)
- Brian E Howard
- Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA.
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Koval M, Ward C, Findley MK, Roser-Page S, Helms MN, Roman J. Extracellular matrix influences alveolar epithelial claudin expression and barrier function. Am J Respir Cell Mol Biol 2009; 42:172-80. [PMID: 19423774 DOI: 10.1165/rcmb.2008-0270oc] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
The lung is dynamically remodeled in response to injury, which alters extracellular matrix composition, and can lead to either healthy or impaired lung regeneration. To determine how changes in extracellular matrix can influence alveolar epithelial barrier function, we examined the expression and function of tight junction proteins by rat alveolar epithelial type II cells cultured on one of three different matrix components: type I collagen or fibronectin, matrix glycoproteins which are highly expressed in injured lungs, or laminin, a basement membrane matrix component. Of note, alveolar epithelial cells cultured for 2 days on fibronectin formed high-resistance barriers and showed continuous claudin-3 and claudin-18 localization to the plasma membrane, as opposed to cells cultured on either type I collagen or laminin, which had low resistance monolayers and had areas of cell-cell contact that were claudin deficient. The barrier formed by cells cultured on fibronectin also had preferential permeability to chloride as compared with sodium. Regardless of the initial matrix composition, alveolar epithelial cells cultured for 5 days formed high-resistance barriers, which correlated with increased claudin-18 localization to the plasma membrane and an increase in zonula occludens-1. Day 5 cells on laminin had significantly higher resistance than cells on either fibronectin or type I collagen. Thus, although alveolar epithelial cells on fibronectin formed rapid barriers, it was at the expense of producing an optimized barrier.
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Affiliation(s)
- Michael Koval
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, Emory University School of Medicine, Whitehead Biomedical Research Building, 615 Michael St., Suite 205, Atlanta, GA 30322, USA.
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