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Zhang J, Liu Y. Epithelial stem cells and niches in lung alveolar regeneration and diseases. CHINESE MEDICAL JOURNAL PULMONARY AND CRITICAL CARE MEDICINE 2024; 2:17-26. [PMID: 38645714 PMCID: PMC11027191 DOI: 10.1016/j.pccm.2023.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
Alveoli serve as the functional units of the lungs, responsible for the critical task of blood-gas exchange. Comprising type I (AT1) and type II (AT2) cells, the alveolar epithelium is continuously subject to external aggressors like pathogens and airborne particles. As such, preserving lung function requires both the homeostatic renewal and reparative regeneration of this epithelial layer. Dysfunctions in these processes contribute to various lung diseases. Recent research has pinpointed specific cell subgroups that act as potential stem or progenitor cells for the alveolar epithelium during both homeostasis and regeneration. Additionally, endothelial cells, fibroblasts, and immune cells synergistically establish a nurturing microenvironment-or "niche"-that modulates these epithelial stem cells. This review aims to consolidate the latest findings on the identities of these stem cells and the components of their niche, as well as the molecular mechanisms that govern them. Additionally, this article highlights diseases that arise due to perturbations in stem cell-niche interactions. We also discuss recent technical innovations that have catalyzed these discoveries. Specifically, this review underscores the heterogeneity, plasticity, and dynamic regulation of these stem cell-niche systems. It is our aspiration that a deeper understanding of the fundamental cellular and molecular mechanisms underlying alveolar homeostasis and regeneration will open avenues for identifying novel therapeutic targets for conditions such as chronic obstructive pulmonary disease (COPD), fibrosis, coronavirus disease 2019 (COVID-19), and lung cancer.
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Affiliation(s)
- Jilei Zhang
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
| | - Yuru Liu
- Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL 60612, USA
- University of Illinois Cancer Center, Chicago, IL 60612, USA
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2
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Shen H, Chen W, Liu Y, Castaldi A, Castillo J, Horie M, Flodby P, Sundar S, Li C, Ji Y, Minoo P, Marconett CN, Zhou B, Borok Z. GRAMD2 + alveolar type I cell plasticity facilitates cell state transitions in organoid culture. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.560801. [PMID: 37905051 PMCID: PMC10614891 DOI: 10.1101/2023.10.17.560801] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
Alveolar epithelial regeneration is critical for normal lung function and becomes dysregulated in disease. While alveolar type 2 (AT2) and club cells are known distal lung epithelial progenitors, determining if alveolar epithelial type 1 (AT1) cells also contribute to alveolar regeneration has been hampered by lack of highly specific mouse models labeling AT1 cells. To address this, the Gramd2 CreERT2 transgenic strain was generated and crossed to Rosa mTmG mice. Extensive cellular characterization, including distal lung immunofluorescence and cytospin staining, confirmed that GRAMD2 + AT1 cells are highly enriched for green fluorescent protein (GFP). Interestingly, Gramd2 CreERT2 GFP + cells were able to form organoids in organoid co-culture with Mlg fibroblasts. Temporal scRNAseq revealed that Gramd2 + AT1 cells transition through numerous intermediate lung epithelial cell states including basal, secretory and AT2 cell in organoids while acquiring proliferative capacity. Our results indicate that Gramd2 + AT1 cells are highly plastic suggesting they may contribute to alveolar regeneration.
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3
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Mižíková I, Thébaud B. Perinatal origins of bronchopulmonary dysplasia-deciphering normal and impaired lung development cell by cell. Mol Cell Pediatr 2023; 10:4. [PMID: 37072570 PMCID: PMC10113423 DOI: 10.1186/s40348-023-00158-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 03/26/2023] [Indexed: 04/20/2023] Open
Abstract
Bronchopulmonary dysplasia (BPD) is a multifactorial disease occurring as a consequence of premature birth, as well as antenatal and postnatal injury to the developing lung. BPD morbidity and severity depend on a complex interplay between prenatal and postnatal inflammation, mechanical ventilation, and oxygen therapy as well as associated prematurity-related complications. These initial hits result in ill-explored aberrant immune and reparative response, activation of pro-fibrotic and anti-angiogenic factors, which further perpetuate the injury. Histologically, the disease presents primarily by impaired lung development and an arrest in lung microvascular maturation. Consequently, BPD leads to respiratory complications beyond the neonatal period and may result in premature aging of the lung. While the numerous prenatal and postnatal stimuli contributing to BPD pathogenesis are relatively well known, the specific cell populations driving the injury, as well as underlying mechanisms are still not well understood. Recently, an effort to gain a more detailed insight into the cellular composition of the developing lung and its progenitor populations has unfold. Here, we provide an overview of the current knowledge regarding perinatal origin of BPD and discuss underlying mechanisms, as well as novel approaches to study the perturbed lung development.
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Affiliation(s)
- I Mižíková
- Experimental Pulmonology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine and University Hospital Cologne, University of Cologne, Cologne, Germany.
| | - B Thébaud
- Sinclair Centre for Regenerative Medicine, Ottawa Hospital Research Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Pediatrics, Children's Hospital of Eastern Ontario (CHEO), CHEO Research Institute, University of Ottawa, Ottawa, ON, Canada
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4
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Burgess CL, Huang J, Bawa P, Alysandratos KD, Minakin K, Morley MP, Babu A, Villacorta-Martin C, Hinds A, Thapa BR, Wang F, Matschulat AM, Morrisey EE, Varelas X, Kotton DN. Generation of human alveolar epithelial type I cells from pluripotent stem cells. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.19.524655. [PMID: 36711505 PMCID: PMC9882278 DOI: 10.1101/2023.01.19.524655] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
In the distal lung, alveolar epithelial type I cells (AT1s) comprise the vast majority of alveolar surface area and are uniquely flattened to allow the diffusion of oxygen into the capillaries. This structure along with a quiescent, terminally differentiated phenotype has made AT1s particularly challenging to isolate or maintain in cell culture. As a result, there is a lack of established models for the study of human AT1 biology, and in contrast to alveolar epithelial type II cells (AT2s), little is known about the mechanisms regulating their differentiation. Here we engineer a human in vitro AT1 model system through the directed differentiation of induced pluripotent stem cells (iPSC). We first define the global transcriptomes of primary adult human AT1s, suggesting gene-set benchmarks and pathways, such as Hippo-LATS-YAP/TAZ signaling, that are enriched in these cells. Next, we generate iPSC-derived AT2s (iAT2s) and find that activating nuclear YAP signaling is sufficient to promote a broad transcriptomic shift from AT2 to AT1 gene programs. The resulting cells express a molecular, morphologic, and functional phenotype reminiscent of human AT1 cells, including the capacity to form a flat epithelial barrier which produces characteristic extracellular matrix molecules and secreted ligands. Our results indicate a role for Hippo-LATS-YAP signaling in the differentiation of human AT1s and demonstrate the generation of viable AT1-like cells from iAT2s, providing an in vitro model of human alveolar epithelial differentiation and a potential source of human AT1s that until now have been challenging to viably obtain from patients.
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Affiliation(s)
- Claire L Burgess
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Jessie Huang
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Pushpinder Bawa
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Konstantinos-Dionysios Alysandratos
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Kasey Minakin
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Michael P Morley
- Penn-CHOP Lung Biology Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Apoorva Babu
- Penn-CHOP Lung Biology Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Carlos Villacorta-Martin
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Anne Hinds
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Bibek R Thapa
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
| | - Feiya Wang
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
| | - Adeline M Matschulat
- Department of Biochemistry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Edward E Morrisey
- Penn-CHOP Lung Biology Institute, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Xaralabos Varelas
- Department of Biochemistry, Boston University Chobanian & Avedisian School of Medicine, Boston, MA, 02118, USA
| | - Darrell N Kotton
- Center for Regenerative Medicine of Boston University and Boston Medical Center, Boston, MA 02118, USA
- The Pulmonary Center and Department of Medicine, Boston University Chobanian & Avedisian School of Medicine, Boston, MA 02118, USA
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5
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Chan M, Liu Y. Function of epithelial stem cell in the repair of alveolar injury. Stem Cell Res Ther 2022; 13:170. [PMID: 35477551 PMCID: PMC9044382 DOI: 10.1186/s13287-022-02847-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 04/11/2022] [Indexed: 01/03/2023] Open
Abstract
Alveoli are the functional units of blood-gas exchange in the lung and thus are constantly exposed to outside environments and frequently encounter pathogens, particles and other harmful substances. For example, the alveolar epithelium is one of the primary targets of the SARS-CoV-2 virus that causes COVID-19 lung disease. Therefore, it is essential to understand the cellular and molecular mechanisms by which the integrity of alveoli epithelial barrier is maintained. Alveolar epithelium comprises two cell types: alveolar type I cells (AT1) and alveolar type II cells (AT2). AT2s have been shown to function as tissue stem cells that repair the injured alveoli epithelium. Recent studies indicate that AT1s and subgroups of proximal airway epithelial cells can also participate alveolar repair process through their intrinsic plasticity. This review discussed the potential mechanisms that drive the reparative behaviors of AT2, AT1 and some proximal cells in responses to injury and how an abnormal repair contributes to some pathological conditions.
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Affiliation(s)
- Manwai Chan
- Department of Biomedical Engineering, University of Illinois College of Medicine, Chicago, IL, 60612, USA
| | - Yuru Liu
- Department of Biomedical Engineering, University of Illinois College of Medicine, Chicago, IL, 60612, USA. .,Department of Pharmacology and Regenerative Medicine, University of Illinois College of Medicine, Chicago, IL, 60612, USA. .,University of Illinois Cancer Center, Chicago, IL60612, USA.
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6
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Zhang ZQ, Tian HT, Liu H, Xie R. The role of macrophage-derived TGF-β1 on SiO 2-induced pulmonary fibrosis: A review. Toxicol Ind Health 2021; 37:240-250. [PMID: 33588701 DOI: 10.1177/0748233721989896] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Silicosis is an occupational fibrotic lung disease caused by inhaling large amounts of crystalline silica dust. Transforming growth factor-β1 (TGF-β1), which is secreted from macrophages, has an important role in the development of this disease. Macrophages can recognize and capture silicon dust, undergo M2 polarization, synthesize TGF-β1 precursors, and secrete them out of the cell where they are activated. Activated TGF-β1 induces cells from different sources, transforming them into myofibroblasts through autocrine and paracrine mechanisms, ultimately causing silicosis. These processes involve complex molecular events, which are not yet fully understood. This systematic summary may further elucidate the location and development of pulmonary fibrosis in the formation of silicosis. In this review, we discussed the proposed cellular and molecular mechanisms of production, secretion, activation of TGF-β1, as well as the mechanisms through which TGF-β1 induces cells from three different sources into myofibroblasts during the pathogenesis of silicosis. This study furthers the medical understanding of the pathogenesis and theoretical basis for diagnosing silicosis, thereby promoting silicosis prevention and treatment.
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Affiliation(s)
- Zhao-Qiang Zhang
- Department of Public Health, 74496Jining Medical University, Jining, China
| | - Hai-Tao Tian
- Department of Public Health, 74496Jining Medical University, Jining, China.,Jining No. 1 People's Hospital, Jining, China
| | - Hu Liu
- Department of Public Health, 74496Jining Medical University, Jining, China
| | - Ruining Xie
- Department of Public Health, 74496Jining Medical University, Jining, China
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7
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Abstract
The mammalian lung epithelium is composed of a wide array of specialized cells that have adapted to survive environmental exposure and perform the tasks necessary for respiration. Although the majority of these cells are remarkably quiescent during adult lung homeostasis, a growing body of literature has demonstrated the capacity of these epithelial lineages to proliferate in response to injury and regenerate lost or damaged cells. In this review, we focus on the regionally distinct lung epithelial cell types that contribute to repair after injury, and we address current controversies regarding whether elite stem cells or frequent facultative progenitors are the predominant participants. We also shed light on the newly emerging approaches for exogenously generating similar lung epithelial lineages from pluripotent stem cells.
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Affiliation(s)
- Konstantinos-Dionysios Alysandratos
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts 02118, USA;
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Michael J Herriges
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts 02118, USA;
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
| | - Darrell N Kotton
- Center for Regenerative Medicine, Boston University and Boston Medical Center, Boston, Massachusetts 02118, USA;
- The Pulmonary Center and Department of Medicine, Boston University School of Medicine, Boston, Massachusetts 02118, USA
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8
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Yang YY, Lin CJ, Wang CC, Chen CM, Kao WJ, Chen YH. Consecutive Hypoxia Decreases Expression of NOTCH3, HEY1, CC10, and FOXJ1 via NKX2-1 Downregulation and Intermittent Hypoxia-Reoxygenation Increases Expression of BMP4, NOTCH1, MKI67, OCT4, and MUC5AC via HIF1A Upregulation in Human Bronchial Epithelial Cells. Front Cell Dev Biol 2020; 8:572276. [PMID: 33015064 PMCID: PMC7500169 DOI: 10.3389/fcell.2020.572276] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/17/2020] [Indexed: 01/11/2023] Open
Abstract
Previous studies have shown that the experimental models of hypoxia-reoxygenation (H/R) mimics the physiological conditions of ischemia-reperfusion and induce oxidative stress and injury in various types of organs, tissues, and cells, both in vivo and in vitro, including human lung adenocarcinoma epithelial cells. Nonetheless, it had not been reported whether H/R affected proliferation, apoptosis, and expression of stem/progenitor cell markers in the bronchial epithelial cells. In this study, we investigated differential effects of consecutive hypoxia and intermittent 24/24-h cycles of H/R on human bronchial epithelial (HBE) cells derived from the same-race and age-matched healthy subjects (i.e., NHBE) and subjects with chronic obstructive pulmonary disease (COPD) (i.e., DHBE). To analyze gene/protein expression during differentiation, both the NHBE and DHBE cells at the 2nd passage were cultured at the air-liquid interface (ALI) in the differentiation medium under normoxia for 3 days, followed by either culturing under hypoxia (1% O2) for consecutively 9 days and then returning to normoxia for another 9 days, or culturing under 24/24-h cycles of H/R (i.e., 24 h of 1% O2 followed by 24 h of 21% O2, repetitively) for 18 days in total, so that all differentiating HBE cells were exposed to hypoxia for a total of 9 days. In both the normal and diseased HBE cells, intermittent H/R significantly increased HIF1A, BMP4, NOTCH1, MKI67, OCT4, and MUC5AC expression, while consecutive hypoxia significantly decreased NKX2-1, NOTCH3, HEY1, CC10, and FOXJ1 expression. Inhibition of HIF1A or NKX2-1 expression by siRNA transfection respectively decreased BMP4/NOTCH1/MKI67/OCT4/MUC5AC and NOTCH3/HEY1/CC10/FOXJ1 expression in the HBE cells cultured under intermittent H/R to the same levels under normoxia. Overexpression of NKX2-1 via cDNA transfection caused more than 2.8-fold increases in NOTCH3, HEY1, and FOXJ1 mRNA levels in the HBE cells cultured under consecutive hypoxia compared to the levels under normoxia. Taken together, our results show for the first time that consecutive hypoxia decreased expression of the co-regulated gene module NOTCH3/HEY1/CC10 and the ciliogenesis-inducing transcription factor gene FOXJ1 via NKX2-1 mRNA downregulation, while intermittent H/R increased expression of the co-regulated gene module BMP4/NOTCH1/MKI67/OCT4 and the predominant airway mucin gene MUC5AC via HIF1A mRNA upregulation.
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Affiliation(s)
- Yung-Yu Yang
- Department of General Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Chao-Ju Lin
- Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Cheng-Chin Wang
- Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan.,Section of Respiratory Therapy, Rueifang Miner Hospital, New Taipei City, Taiwan
| | - Chieh-Min Chen
- Graduate Institute of Microbiology and Immunology, National Defense Medical Center, Taipei, Taiwan
| | - Wen-Jen Kao
- Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan
| | - Yi-Hui Chen
- Graduate Institute of Aerospace and Undersea Medicine, National Defense Medical Center, Taipei, Taiwan
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9
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Donati Y, Blaskovic S, Ruchonnet-Métrailler I, Lascano Maillard J, Barazzone-Argiroffo C. Simultaneous isolation of endothelial and alveolar epithelial type I and type II cells during mouse lung development in the absence of a transgenic reporter. Am J Physiol Lung Cell Mol Physiol 2020; 318:L619-L630. [PMID: 32022591 DOI: 10.1152/ajplung.00227.2019] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mouse lung developmental maturation and final alveolarization phase begin at birth. During this dynamic process, alveolar cells modify their morphology and anchorage to the extracellular matrix. In particular, alveolar epithelial cell (AEC) type I undergo cytoplasmic flattening and folding to ensure alveoli lining. We developed FACS conditions for simultaneous isolation of alveolar epithelial and endothelial cells in the absence of specific reporters during the early and middle alveolar phase. We evidenced for the first time a pool of extractable epithelial cell populations expressing high levels of podoplanin at postnatal day (pnd)2, and we confirmed by RT-qPCR that these cells are already differentiated but still immature AEC type I. Maturation causes a decrease in isolation yields, reflecting the morphological changes that these cell populations are undergoing. Moreover, we find that major histocompatibility complex II (MHCII), reported as a good marker of AEC type II, is poorly expressed at pnd2 but highly present at pnd8. Combined experiments using LysoTracker and MHCII demonstrate the de novo acquisition of MCHII in AEC type II during lung alveolarization. The lung endothelial populations exhibit FACS signatures from vascular and lymphatic compartments. They can be concomitantly followed throughout alveolar development and were obtained with a noticeable increased yield at the last studied time point (pnd16). Our results provide new insights into early lung alveolar cell isolation feasibility and represent a valuable tool for pure AEC type I preparation as well as further in vitro two- and three-dimensional studies.
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Affiliation(s)
- Yves Donati
- Department of Pediatrics, Gynecology, and Obstetrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Sanja Blaskovic
- Department of Pediatrics, Gynecology, and Obstetrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Isabelle Ruchonnet-Métrailler
- Department of Pediatrics, Gynecology, and Obstetrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | | | - Constance Barazzone-Argiroffo
- Department of Pediatrics, Gynecology, and Obstetrics, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Pathology and Immunology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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10
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Abstract
The epithelial lining of the lung is often the first point of interaction between the host and inhaled pathogens, allergens and medications. Epithelial cells are therefore the main focus of studies which aim to shed light on host-pathogen interactions, to dissect the mechanisms of local host immunity and study toxicology. If these studies are not to be conducted exclusively
in vivo, it is imperative that
in vitro models are developed with a high
in vitro-
in vivo correlation. We describe here a co-culture model of the bovine alveolus, designed to overcome some of the limitations encountered with mono-culture and live animal models. Our system includes bovine pulmonary arterial endothelial cells (BPAECs) seeded onto a permeable membrane in 24 well Transwell format. The BPAECs are overlaid with immortalised bovine alveolar type II epithelial cells and cultured at air-liquid interface for 14 days before use; in our case to study host-mycobacterial interactions. Characterisation of novel cell lines and the co-culture model have provided compelling evidence that immortalised bovine alveolar type II cells are an authentic substitute for primary alveolar type II cells and their co-culture with BPAECs provides a physiologically relevant
in vitro model of the bovine alveolus. The co-culture model may be used to study dynamic intracellular and extracellular host-pathogen interactions, using proteomics, genomics, live cell imaging, in-cell ELISA and confocal microscopy. The model presented in this article enables other researchers to establish an
in vitro model of the bovine alveolus that is easy to set up, malleable and serves as a comparable alternative to
in vivo models, whilst allowing study of early host-pathogen interactions, currently not feasible
in vivo. The model therefore achieves one of the 3Rs objectives in that it replaces the use of animals in research of bovine respiratory diseases.
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Affiliation(s)
- Diane Lee
- School of Veterinary Medicine, University of Surrey, Guildford, Surrey, GU2 7AL, UK
| | - Mark Chambers
- School of Veterinary Medicine, University of Surrey, Guildford, Surrey, GU2 7AL, UK
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11
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O'Reilly MA. Giving New Identities to Alveolar Epithelial Type I Cells. Am J Respir Cell Mol Biol 2018; 56:277-278. [PMID: 28248135 DOI: 10.1165/rcmb.2016-0383ed] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Affiliation(s)
- Michael A O'Reilly
- 1 Department of Pediatrics School of Medicine and Dentistry The University of Rochester Rochester, New York
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12
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Beers MF, Moodley Y. When Is an Alveolar Type 2 Cell an Alveolar Type 2 Cell? A Conundrum for Lung Stem Cell Biology and Regenerative Medicine. Am J Respir Cell Mol Biol 2017; 57:18-27. [PMID: 28326803 DOI: 10.1165/rcmb.2016-0426ps] [Citation(s) in RCA: 81] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Generating mature, differentiated, adult lung cells from pluripotent cells, such as induced pluripotent stem cells and embryonic stem cells, offers the hope of both generating disease-specific in vitro models and creating definitive and personalized therapies for a host of debilitating lung parenchymal and airway diseases. With the goal of advancing lung-regenerative medicine, several groups have developed and reported on protocols using defined media, coculture with mesenchymal components, or sequential treatments mimicking lung development, to obtain distal lung epithelial cells from stem cell precursors. However, there remains significant controversy about the degree of differentiation of these cells compared with their primary counterparts, coupled with a lack of consistency or uniformity in assessing the resultant phenotypes. Given the inevitable, exponential expansion of these approaches and the probable, but yet-to-emerge second and higher generation techniques to create such assets, we were prompted to pose the question, what makes a lung epithelial cell a lung epithelial cell? More specifically for this Perspective, we also posed the question, what are the minimum features that constitute an alveolar type (AT) 2 epithelial cell? In addressing this, we summarize a body of work spanning nearly five decades, amassed by a series of "lung epithelial cell biology pioneers," which carefully describes well characterized molecular, functional, and morphological features critical for discriminately assessing an AT2 phenotype. Armed with this, we propose a series of core criteria to assist the field in confirming that cells obtained following a differentiation protocol are indeed mature and functional AT2 epithelial cells.
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Affiliation(s)
- Michael F Beers
- 1 Lung Epithelial Biology Laboratories, Penn Center for Pulmonary Biology, Pulmonary and Critical Care Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; and
| | - Yuben Moodley
- 2 University of Western Australia, Harry Perkins Research Institute, Fiona Stanley Hospital, Murdoch, Western Australia, Australia
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13
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Cell-specific expression of aquaporin-5 (Aqp5) in alveolar epithelium is directed by GATA6/Sp1 via histone acetylation. Sci Rep 2017; 7:3473. [PMID: 28615712 PMCID: PMC5471216 DOI: 10.1038/s41598-017-03152-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 04/25/2017] [Indexed: 01/23/2023] Open
Abstract
Epigenetic regulation of differentiation-related genes is poorly understood. We previously reported that transcription factors GATA6 and Sp1 interact with and activate the rat proximal 358-bp promoter/enhancer (p358P/E) of lung alveolar epithelial type I (AT1) cell-specific gene aquaporin-5 (Aqp5). In this study, we found that histone deacetylase (HDAC) inhibitor suberoylanilide hydroxamic acid (SAHA) increased AQP5 expression and Sp1-mediated transcription of p358P/E. HDAC3 overexpression inhibited Sp1-mediated Aqp5 activation, while HDAC3 knockdown augmented AQP5 protein expression. Knockdown of GATA6 or transcriptional co-activator/histone acetyltransferase p300 decreased AQP5 expression, while p300 overexpression enhanced p358P/E activation by GATA6 and Sp1. GATA6 overexpression, SAHA treatment or HDAC3 knockdown increased histone H3 (H3) but not histone H4 (H4) acetylation within the homologous p358P/E region of mouse Aqp5. HDAC3 binds to Sp1 and HDAC3 knockdown increased interaction of GATA6/Sp1, GATA6/p300 and Sp1/p300. These results indicate that GATA6 and HDAC3 control Aqp5 transcription via modulation of H3 acetylation/deacetylation, respectively, through competition for binding to Sp1, and suggest that p300 modulates acetylation and/or interacts with GATA6/Sp1 to regulate Aqp5 transcription. Cooperative interactions among transcription factors and histone modifications regulate Aqp5 expression during alveolar epithelial cell transdifferentiation, suggesting that HDAC inhibitors may enhance repair by promoting acquisition of AT1 cell phenotype.
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14
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Yan Y, Tan MW, Xue X, Ding XY, Wang GK, Xu ZY. Involvement of Oct4 in the pathogenesis of thoracic aortic dissection via inducing the dedifferentiated phenotype of human aortic smooth muscle cells by directly upregulating KLF5. J Thorac Cardiovasc Surg 2016; 152:820-829.e4. [PMID: 27353340 DOI: 10.1016/j.jtcvs.2016.05.036] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 04/27/2016] [Accepted: 05/20/2016] [Indexed: 12/29/2022]
Abstract
OBJECTIVE To investigate the expression of Oct4 in human thoracic aortic dissection (TAD) and the regulation mechanisms of Oct4 on phenotype transition of human aortic smooth muscle cells (HASMCs). METHODS Aortic samples from TAD patients (n = 12) and organ donors (n = 6) were collected. qRT-PCR, western blot, and immunohistochemistry were performed to identify Oct4 expression in aortic media. Immunofluorescence was performed to analyze Oct4 expression in primary HASMCs. Oct4A and Oct4B isoforms were detected. Gain-of-function experiments were performed to determine the effects of Oct4 on HASMC phenotype transition. Chromatin immunoprecipitation, luciferase assay, and rescue experiments were performed to analyze mechanisms of Oct4 on HASMC phenotype transition. RESULTS Oct4 expression levels, especially the Oct4A isoform, were significantly higher in TAD patients compared with normal controls. Notably, Oct4 presented a strong and strict nuclear localization in primary HASMCs of TAD patients but a mild and diffuse distribution in both cytoplasm and nucleus in the control group. Overexpression of Oct4 induced dedifferentiation of HASMCs characterized by decreased contractile proteins and elevated migration capability. Krüppel-like factor 5 (KLF5) was found to be a directly regulated target gene of Oct4 in HASMCs. Furthermore, downregulation of KLF5 significantly alleviated the effects of Oct4 on phenotype transition of HASMCs. CONCLUSIONS Oct4 expression was significantly upregulated in aortic tissues and primary HASMCs of TAD patients. The increased Oct4 induced phenotype transition of HASMCs from the contractile type to the synthetic type by directly upregulating KLF5.
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Affiliation(s)
- Yan Yan
- Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, Zhejiang, China
| | - Meng-Wei Tan
- Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, Zhejiang, China.
| | - Xiang Xue
- Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, Zhejiang, China
| | - Xue-Yan Ding
- Cardiovascular Therapeutic Centre, The 117 Hospital of the Chinese People's Liberation Army, Hangzhou, Zhejiang, China
| | - Guo-Kun Wang
- Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, Zhejiang, China
| | - Zhi-Yun Xu
- Department of Cardiothoracic Surgery, Changhai Hospital, Second Military Medical University, Shanghai, Zhejiang, China.
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15
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Yee M, Gelein R, Mariani TJ, Lawrence BP, O'Reilly MA. The Oxygen Environment at Birth Specifies the Population of Alveolar Epithelial Stem Cells in the Adult Lung. Stem Cells 2016; 34:1396-406. [PMID: 26891117 DOI: 10.1002/stem.2330] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 11/20/2015] [Accepted: 12/17/2015] [Indexed: 12/11/2022]
Abstract
Alveolar epithelial type II cells (AEC2) maintain pulmonary homeostasis by producing surfactant, expressing innate immune molecules, and functioning as adult progenitor cells for themselves and alveolar epithelial type I cells (AEC1). How the proper number of alveolar epithelial cells is determined in the adult lung is not well understood. Here, BrdU labeling, genetic lineage tracing, and targeted expression of the anti-oxidant extracellular superoxide dismutase in AEC2s are used to show how the oxygen environment at birth influences postnatal expansion of AEC2s and AEC1s in mice. Birth into low (12%) or high (≥60%) oxygen stimulated expansion of AEC2s through self-renewal and differentiation of the airway Scgb1a1 + lineage. This non-linear or hormesis response to oxygen was specific for the alveolar epithelium because low oxygen stimulated and high oxygen inhibited angiogenesis as defined by changes in V-cadherin and PECAM (CD31). Although genetic lineage tracing studies confirmed adult AEC2s are stem cells for AEC1s, we found no evidence that postnatal growth of AEC1s were derived from self-renewing Sftpc + or the Scbg1a1 + lineage of AEC2s. Taken together, our results show how a non-linear response to oxygen at birth promotes expansion of AEC2s through two distinct lineages. Since neither lineage contributes to the postnatal expansion of AEC1s, the ability of AEC2s to function as stem cells for AEC1s appears to be restricted to the adult lung. Stem Cells 2016;34:1396-1406.
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Affiliation(s)
- Min Yee
- Department of Pediatrics, The University of Rochester, Rochester, New York, USA
| | - Robert Gelein
- Department of Environmental Medicine, School of Medicine and Dentistry, The University of Rochester, Rochester, New York, USA
| | - Thomas J Mariani
- Department of Pediatrics, The University of Rochester, Rochester, New York, USA
| | - B Paige Lawrence
- Department of Environmental Medicine, School of Medicine and Dentistry, The University of Rochester, Rochester, New York, USA
| | - Michael A O'Reilly
- Department of Pediatrics, The University of Rochester, Rochester, New York, USA
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16
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Lin SE, Barrette AM, Chapin C, Gonzales LW, Gonzalez RF, Dobbs LG, Ballard PL. Expression of human carcinoembryonic antigen-related cell adhesion molecule 6 and alveolar progenitor cells in normal and injured lungs of transgenic mice. Physiol Rep 2015; 3:3/12/e12657. [PMID: 26702074 PMCID: PMC4760449 DOI: 10.14814/phy2.12657] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Accepted: 11/18/2015] [Indexed: 01/11/2023] Open
Abstract
Carcinoembryonic antigen-related cell adhesion molecule 6 (CEACAM6) is expressed in the epithelium of various primate tissues, including lung airway and alveoli. In human lung, CEACAM6 is developmentally and hormonally regulated, protects surfactant function, has anti-apoptotic activity and is dysregulated in cancers. We hypothesized that alveolar CEACAM6 expression increases in lung injury and promotes cell proliferation during repair. Studies were performed in CEABAC transgenic mice-containing human CEACAM genes. The level of CEACAM6 in adult CEABAC lung was comparable to that in human infants; expression occurred in epithelium of airways and of some alveoli but rarely co-localized with markers of type I or type II cells. Ten days after bleomycin instillation, both the number of CEACAM6(+) cells and immunostaining intensity were elevated in injured lung areas, and there was increased co-localization with type I and II cell markers. To specifically address type II cells, we crossed CEABAC mice with animals expressing EGFP driven by the SP-C promoter. After bleomycin injury, partially flattened, elongated epithelial cells were observed that expressed type I cell markers and were primarily either EGFP(+) or CEACAM6(+). In cell cycle studies, mitosis was greater in CEACAM6(+) non-type II cells versus CEACAM6(+)/EGFP(+) cells. CEACAM6 epithelial expression was also increased after hyperoxic exposure and LPS instillation, suggesting a generalized response to acute lung injuries. We conclude that CEACAM6 expression is comparable in human lung and the CEABAC mouse. CEACAM6 in this model appears to be a marker of a progenitor cell population that contributes to alveolar epithelial cell replenishment after lung injury.
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Affiliation(s)
- Shin-E Lin
- Department of Pediatrics, University of California San Francisco, San Francisco, California
| | - Anne Marie Barrette
- Department of Pediatrics, University of California San Francisco, San Francisco, California
| | - Cheryl Chapin
- Department of Pediatrics, University of California San Francisco, San Francisco, California
| | - Linda W Gonzales
- Department of Pediatrics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Robert F Gonzalez
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
| | - Leland G Dobbs
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, California
| | - Philip L Ballard
- Department of Pediatrics, University of California San Francisco, San Francisco, California
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17
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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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18
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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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19
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Vanderbilt JN, Gonzalez RF, Allen L, Gillespie A, Leaffer D, Dean WB, Chapin C, Dobbs LG. High-efficiency type II cell-enhanced green fluorescent protein expression facilitates cellular identification, tracking, and isolation. Am J Respir Cell Mol Biol 2015; 53:14-21. [PMID: 25692334 DOI: 10.1165/rcmb.2014-0348ma] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
We have developed a transgenic mouse expressing enhanced green fluorescent protein (EGFP) in virtually all type II (TII) alveolar epithelial cells. The CBG mouse (SPC-BAC-EGFP) contains a bacterial artificial chromosome modified to express EGFP within the mouse surfactant protein (SP)-C gene 3' untranslated region. EGFP mRNA expression is limited to the lung. EGFP fluorescence is both limited to and exhibited by all cells expressing pro-SP-C; fluorescence is uniform throughout all lobes of the lung and does not change as mice age. EGFP(+) cells also express SP-B but do not express podoplanin, a type I (TI) cell marker. CBG mice show no evidence of lung disease with aging. In 3 hours, TII cells can be isolated in >99% purity from CBG mice by FACS; the yield of 3.7 ± 0.6 × 10(6) cells represents approximately 25 to 60% of the TII cells in the lung. By FACS analysis, approximately 0.9% of TII cells are in mitosis in uninjured lungs; after bleomycin injury, 4.1% are in mitosis. Because EGFP fluorescence can be detected for >14 days in culture, at a time that SP-C mRNA expression is essentially nil, this line may be useful for tracking TII cells in culture and in vivo. When CBG mice are crossed to transgenic mice expressing rat podoplanin, TI and TII cells can be easily simultaneously identified and isolated. When bred to other strains of mice, EGFP expression can be used to identify TII cells without the need for immunostaining for SP-C. These mice should be useful in models of mouse pulmonary disease and in studies of TII cell biology, biochemistry, and genetics.
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Affiliation(s)
| | | | | | | | | | | | | | - Leland G Dobbs
- 1 Cardiovascular Research Institute and.,Departments of 2 Pediatrics and.,3 Medicine, University of California, San Francisco, San Francisco, California
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20
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Domm W, Misra RS, O'Reilly MA. Affect of Early Life Oxygen Exposure on Proper Lung Development and Response to Respiratory Viral Infections. Front Med (Lausanne) 2015; 2:55. [PMID: 26322310 PMCID: PMC4530667 DOI: 10.3389/fmed.2015.00055] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/27/2015] [Indexed: 12/22/2022] Open
Abstract
Children born preterm often exhibit reduced lung function and increased severity of response to respiratory viruses, suggesting that premature birth has compromised proper development of the respiratory epithelium and innate immune defenses. Increasing evidence suggests that premature birth promotes aberrant lung development likely due to the neonatal oxygen transition occurring before pulmonary development has matured. Given that preterm infants are born at a point of time where their immune system is also still developing, early life oxygen exposure may also be disrupting proper development of innate immunity. Here, we review current literature in hopes of stimulating research that enhances understanding of how the oxygen environment at birth influences lung development and host defense. This knowledge may help identify those children at risk for disease and ideally culminate in the development of novel therapies that improve their health.
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Affiliation(s)
- William Domm
- Department of Pediatrics, School of Medicine and Dentistry, The University of Rochester , Rochester, NY , USA ; Department of Environmental Medicine, School of Medicine and Dentistry, The University of Rochester , Rochester, NY , USA
| | - Ravi S Misra
- Department of Pediatrics, School of Medicine and Dentistry, The University of Rochester , Rochester, NY , USA
| | - Michael A O'Reilly
- Department of Pediatrics, School of Medicine and Dentistry, The University of Rochester , Rochester, NY , USA ; Department of Environmental Medicine, School of Medicine and Dentistry, The University of Rochester , Rochester, NY , USA
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21
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Mutze K, Vierkotten S, Milosevic J, Eickelberg O, Königshoff M. Enolase 1 (ENO1) and protein disulfide-isomerase associated 3 (PDIA3) regulate Wnt/β-catenin-driven trans-differentiation of murine alveolar epithelial cells. Dis Model Mech 2015; 8:877-90. [PMID: 26035385 PMCID: PMC4527283 DOI: 10.1242/dmm.019117] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 05/12/2015] [Indexed: 12/30/2022] Open
Abstract
The alveolar epithelium represents a major site of tissue destruction during lung injury. It consists of alveolar epithelial type I (ATI) and type II (ATII) cells. ATII cells are capable of self-renewal and exert progenitor function for ATI cells upon alveolar epithelial injury. Cell differentiation pathways enabling this plasticity and allowing for proper repair, however, are poorly understood. Here, we applied proteomics, expression analysis and functional studies in primary murine ATII cells to identify proteins and molecular mechanisms involved in alveolar epithelial plasticity. Mass spectrometry of cultured ATII cells revealed a reduction of carbonyl reductase 2 (CBR2) and an increase in enolase 1 (ENO1) and protein disulfide-isomerase associated 3 (PDIA3) protein expression during ATII-to-ATI cell trans-differentiation. This was accompanied by increased Wnt/β-catenin signaling, as analyzed by qRT-PCR and immunoblotting. Notably, ENO1 and PDIA3, along with T1α (podoplanin; an ATI cell marker), exhibited decreased protein expression upon pharmacological and molecular Wnt/β-catenin inhibition in cultured ATII cells, whereas CBR2 levels were stabilized. Moreover, we analyzed primary ATII cells from mice with bleomycin-induced lung injury, a model exhibiting activated Wnt/β-catenin signaling in vivo. We observed reduced CBR2 significantly correlating with surfactant protein C (SFTPC), whereas ENO1 and PDIA3 along with T1α were increased in injured ATII cells. Finally, siRNA-mediated knockdown of ENO1, as well as PDIA3, in primary ATII cells led to reduced T1α expression, indicating diminished cell trans-differentiation. Our data thus identified proteins involved in ATII-to-ATI cell trans-differentiation and suggest a Wnt/β-catenin-driven functional role of ENO1 and PDIA3 in alveolar epithelial cell plasticity in lung injury and repair. Summary: The authors identified proteins involved in Wnt/β-catenin-driven alveolar epithelial plasticity in lung injury and repair.
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Affiliation(s)
- Kathrin Mutze
- Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany
| | - Sarah Vierkotten
- Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany
| | | | - Oliver Eickelberg
- Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany
| | - Melanie Königshoff
- Comprehensive Pneumology Center (CPC), Helmholtz Zentrum München, University Hospital, Ludwig-Maximilians University, 81377 Munich, Member of the German Center for Lung Research (DZL), Germany
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22
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Jain R, Barkauskas CE, Takeda N, Bowie EJ, Aghajanian H, Wang Q, Padmanabhan A, Manderfield LJ, Gupta M, Li D, Li L, Trivedi CM, Hogan BLM, Epstein JA. Plasticity of Hopx(+) type I alveolar cells to regenerate type II cells in the lung. Nat Commun 2015; 6:6727. [PMID: 25865356 PMCID: PMC4396689 DOI: 10.1038/ncomms7727] [Citation(s) in RCA: 211] [Impact Index Per Article: 23.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 02/23/2015] [Indexed: 12/22/2022] Open
Abstract
The plasticity of differentiated cells in adult tissues undergoing repair is an area of intense research. Pulmonary alveolar type II cells produce surfactant and function as progenitors in the adult, demonstrating both self-renewal and differentiation into gas exchanging type I cells. In vivo, type I cells are thought to be terminally differentiated and their ability to give rise to alternate lineages has not been reported. Here we show that Hopx becomes restricted to type I cells during development. However, unexpectedly, lineage-labelled Hopx(+) cells both proliferate and generate type II cells during adult alveolar regrowth following partial pneumonectomy. In clonal 3D culture, single Hopx(+) type I cells generate organoids composed of type I and type II cells, a process modulated by TGFβ signalling. These findings demonstrate unanticipated plasticity of type I cells and a bidirectional lineage relationship between distinct differentiated alveolar epithelial cell types in vivo and in single-cell culture.
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Affiliation(s)
- Rajan Jain
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Christina E Barkauskas
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke Medicine, Durham, North Carolina 27710, USA
| | - Norifumi Takeda
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Emily J Bowie
- Department of Cell Biology, Duke Medicine, Durham, North Carolina 27710, USA
| | - Haig Aghajanian
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Qiaohong Wang
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Arun Padmanabhan
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Lauren J Manderfield
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Mudit Gupta
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Deqiang Li
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Li Li
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke Medicine, Durham, North Carolina 27710, USA
| | - Chinmay M Trivedi
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Brigid L M Hogan
- Department of Cell Biology, Duke Medicine, Durham, North Carolina 27710, USA
| | - Jonathan A Epstein
- Department of Cell and Developmental Biology, Penn Cardiovascular Institute, Institute of Regenerative Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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23
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Mock JR, Garibaldi BT, Aggarwal NR, Jenkins J, Limjunyawong N, Singer BD, Chau E, Rabold R, Files DC, Sidhaye V, Mitzner W, Wagner EM, King LS, D’Alessio FR. Foxp3+ regulatory T cells promote lung epithelial proliferation. Mucosal Immunol 2014; 7:1440-51. [PMID: 24850425 PMCID: PMC4205163 DOI: 10.1038/mi.2014.33] [Citation(s) in RCA: 100] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Accepted: 04/06/2014] [Indexed: 02/04/2023]
Abstract
Acute respiratory distress syndrome (ARDS) causes significant morbidity and mortality each year. There is a paucity of information regarding the mechanisms necessary for ARDS resolution. Foxp3(+) regulatory T cells (Foxp3(+) T(reg) cells) have been shown to be an important determinant of resolution in an experimental model of lung injury. We demonstrate that intratracheal delivery of endotoxin (lipopolysaccharide) elicits alveolar epithelial damage from which the epithelium undergoes proliferation and repair. Epithelial proliferation coincided with an increase in Foxp3(+) T(reg) cells in the lung during the course of resolution. To dissect the role that Foxp3(+) T(reg) cells exert on epithelial proliferation, we depleted Foxp3(+) T(reg) cells, which led to decreased alveolar epithelial proliferation and delayed lung injury recovery. Furthermore, antibody-mediated blockade of CD103, an integrin, which binds to epithelial expressed E-cadherin decreased Foxp3(+) T(reg) numbers and decreased rates of epithelial proliferation after injury. In a non-inflammatory model of regenerative alveologenesis, left lung pneumonectomy, we found that Foxp3(+) T(reg) cells enhanced epithelial proliferation. Moreover, Foxp3(+) T(reg) cells co-cultured with primary type II alveolar cells (AT2) directly increased AT2 cell proliferation in a CD103-dependent manner. These studies provide evidence of a new and integral role for Foxp3(+) T(reg) cells in repair of the lung epithelium.
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Affiliation(s)
- Jason R. Mock
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Brian T. Garibaldi
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Neil R. Aggarwal
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - John Jenkins
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Nathachit Limjunyawong
- Department of Medicine and Department of Environmental Health Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Benjamin D. Singer
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Eric Chau
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Richard Rabold
- Department of Medicine and Department of Environmental Health Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Daniel C. Files
- Division of Pulmonary, Critical Care, Allergy, and Immunology, Department of Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina
| | - Venkataramana Sidhaye
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Wayne Mitzner
- Department of Medicine and Department of Environmental Health Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Elizabeth M. Wagner
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Landon S. King
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Franco R. D’Alessio
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland
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24
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Abstract
I am deeply honored to have been awarded an American Thoracic Society Recognition Award for Scientific Accomplishment for 2014. Over the last 20 years, it has become clear that the alveolar epithelium, my area of research focus, is not simply a gas exchange surface and barrier to leakage of fluid and protein into the alveoli, but is an active participant in the pathogenesis of a number of lung diseases, including pulmonary fibrosis. Recognition by this Award stimulates a review of the awardee's contributions to the field, as summarized in this perspective.
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Affiliation(s)
- Zea Borok
- Will Rogers Institute Pulmonary Research Center, Division of Pulmonary, Critical Care and Sleep Medicine, Department of Medicine, Keck School of Medicine, University of Southern California, Los Angeles, California
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25
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Bove PF, Dang H, Cheluvaraju C, Jones LC, Liu X, O'Neal WK, Randell SH, Schlegel R, Boucher RC. Breaking the in vitro alveolar type II cell proliferation barrier while retaining ion transport properties. Am J Respir Cell Mol Biol 2014; 50:767-76. [PMID: 24191670 DOI: 10.1165/rcmb.2013-0071oc] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Alveolar type (AT)I and ATII cells are central to maintaining normal alveolar fluid homeostasis. When disrupted, they contribute to the pathogenesis of acute lung injury (ALI) and acute respiratory distress syndrome. Research on ATII cells has been limited by the inability to propagate primary cells in vitro to study their specific functional properties. Moreover, primary ATII cells in vitro quickly transdifferentiate into nonproliferative "ATI-like" cells under traditional culture conditions. Recent studies have demonstrated that normal and tumor cells grown in culture with a combination of fibroblast (feeder cells) and a pharmacological Rho kinase inhibitor (Y-27632) exhibit indefinite cell proliferation that resembled a "conditionally reprogrammed cell" phenotype. Using this coculture system, we found that primary human ATII cells (1) proliferated at an exponential rate, (2) established epithelial colonies expressing ATII-specific and "ATI-like" mRNA and proteins after serial passage, (3) up-regulated genes important in cell proliferation and migration, and (4) on removal of feeder cells and Rho kinase inhibitor under air-liquid interface conditions, exhibited bioelectric and volume transport characteristics similar to freshly cultured ATII cells. Collectively, our results demonstrate that this novel coculture technique breaks the in vitro ATII cell proliferation barrier while retaining cell-specific functional properties. This work will allow for a significant increase in studies designed to elucidate ATII cell function with the goal of accelerating the development of novel therapies for alveolar diseases.
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Affiliation(s)
- Peter F Bove
- 1 Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center and
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26
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Calle EA, Ghaedi M, Sundaram S, Sivarapatna A, Tseng MK, Niklason LE. Strategies for whole lung tissue engineering. IEEE Trans Biomed Eng 2014; 61:1482-96. [PMID: 24691527 PMCID: PMC4126648 DOI: 10.1109/tbme.2014.2314261] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Recent work has demonstrated the feasibility of using decellularized lung extracellular matrix scaffolds to support the engineering of functional lung tissue in vitro. Rendered acellular through the use of detergents and other reagents, the scaffolds are mounted in organ-specific bioreactors where cells in the scaffold are provided with nutrients and appropriate mechanical stimuli such as ventilation and perfusion. Though initial studies are encouraging, a great deal remains to be done to advance the field and transition from rodent lungs to whole human tissue engineered lungs. To do so, a variety of hurdles must be overcome. In particular, a reliable source of human-sized scaffolds, as well as a method of terminal sterilization of scaffolds, must be identified. Continued research in lung cell and developmental biology will hopefully help identify the number and types of cells that will be required to regenerate functional lung tissue. Finally, bioreactor designs must be improved in order to provide more precise ventilation stimuli and vascular perfusion in order to avoid injury to or death of the cells cultivated within the scaffold. Ultimately, the success of efforts to engineer a functional lung in vitro will critically depend on the ability to create a fully endothelialized vascular network that provides sufficient barrier function and alveolar-capillary surface area to exchange gas at rates compatible with healthy lung function.
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Affiliation(s)
- Elizabeth A. Calle
- Department of Biomedical Engineering, Yale University, New Haven, CT 06519 USA
| | - Mahboobe Ghaedi
- Department of Anesthesia, Yale University, New Haven, CT 06519 USA
| | - Sumati Sundaram
- Department of Anesthesia, Yale University, New Haven, CT 06519 USA
| | - Amogh Sivarapatna
- Department of Biomedical Engineering, Yale University, New Haven, CT 06519 USA
| | - Michelle K. Tseng
- Department of Biomedical Engineering, Yale University, New Haven, CT 06519 USA
| | - Laura E. Niklason
- Department of Anesthesia and Department of Biomedical Engineering, Yale University, New Haven, CT 06519 USA
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27
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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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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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29
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Zhao L, Yee M, O'Reilly MA. Transdifferentiation of alveolar epithelial type II to type I cells is controlled by opposing TGF-β and BMP signaling. Am J Physiol Lung Cell Mol Physiol 2013; 305:L409-18. [PMID: 23831617 DOI: 10.1152/ajplung.00032.2013] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Alveolar epithelial type II (ATII) cells are essential for maintaining normal lung homeostasis because they produce surfactant, express innate immune proteins, and can function as progenitors for alveolar epithelial type I (ATI) cells. Although autocrine production of transforming growth factor (TGF)-β1 has been shown to promote the transdifferentiation of primary rat ATII to ATI cells in vitro, mechanisms controlling this process still remain poorly defined. Here, evidence is provided that Tgf-β1, -2, -3 mRNA and phosphorylated SMAD2 and SMAD3 significantly increase as primary cultures of mouse ATII cells transdifferentiate to ATI cells. Concomitantly, bone morphogenetic protein (Bmp)-2 and -4 mRNA, and phosphorylated SMAD1/5/8 expression decrease. Exogenously supplied recombinant human TGF-β1 inhibited BMP signaling and enhanced transdifferentiation by promoting the loss of ATII cell-specific gene expression and weakly stimulating ATI cell-specific gene expression. On the other hand, exogenously supplied recombinant human BMP-4 inhibited TGF-β signaling and delayed transdifferentiation by inhibiting the gain in ATI cell-specific gene expression and weakly delaying the loss of ATII cell-specific gene expression. In mouse lung epithelial (MLE15) cells, small-interfering RNA (siRNA) knockdown of TGF-β receptor type-1 enhanced basal expression of ATII genes while siRNA RNA knockdown of BMP receptors type-1a and -1b enhanced basal expression of ATI genes. Together, these results suggest that the rate of ATII cell transdifferentiation is controlled by the opposing actions of BMP and TGF-β signaling that switch during the process of transdifferentiation.
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Affiliation(s)
- Lan Zhao
- Dept. of Pediatrics, Box 850, The Univ. of Rochester, School of Medicine and Dentistry, 601 Elmwood Ave., Rochester NY 14642.
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30
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Barkauskas CE, Cronce MJ, Rackley CR, Bowie EJ, Keene DR, Stripp BR, Randell SH, Noble PW, Hogan BLM. Type 2 alveolar cells are stem cells in adult lung. J Clin Invest 2013; 123:3025-36. [PMID: 23921127 DOI: 10.1172/jci68782] [Citation(s) in RCA: 1137] [Impact Index Per Article: 103.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Accepted: 04/11/2013] [Indexed: 02/06/2023] Open
Abstract
Gas exchange in the lung occurs within alveoli, air-filled sacs composed of type 2 and type 1 epithelial cells (AEC2s and AEC1s), capillaries, and various resident mesenchymal cells. Here, we use a combination of in vivo clonal lineage analysis, different injury/repair systems, and in vitro culture of purified cell populations to obtain new information about the contribution of AEC2s to alveolar maintenance and repair. Genetic lineage-tracing experiments showed that surfactant protein C-positive (SFTPC-positive) AEC2s self renew and differentiate over about a year, consistent with the population containing long-term alveolar stem cells. Moreover, if many AEC2s were specifically ablated, high-resolution imaging of intact lungs showed that individual survivors undergo rapid clonal expansion and daughter cell dispersal. Individual lineage-labeled AEC2s placed into 3D culture gave rise to self-renewing "alveolospheres," which contained both AEC2s and cells expressing multiple AEC1 markers, including HOPX, a new marker for AEC1s. Growth and differentiation of the alveolospheres occurred most readily when cocultured with primary PDGFRα⁺ lung stromal cells. This population included lipofibroblasts that normally reside close to AEC2s and may therefore contribute to a stem cell niche in the murine lung. Results suggest that a similar dynamic exists between AEC2s and mesenchymal cells in the human lung.
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Affiliation(s)
- Christina E Barkauskas
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Duke University Medical Center, Durham, North Carolina, USA
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31
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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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32
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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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33
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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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Schmeckebier S, Mauritz C, Katsirntaki K, Sgodda M, Puppe V, Duerr J, Schubert SC, Schmiedl A, Lin Q, Paleček J, Draeger G, Ochs M, Zenke M, Cantz T, Mall MA, Martin U. Keratinocyte growth factor and dexamethasone plus elevated cAMP levels synergistically support pluripotent stem cell differentiation into alveolar epithelial type II cells. Tissue Eng Part A 2013; 19:938-51. [PMID: 23176317 DOI: 10.1089/ten.tea.2012.0066] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Alveolar epithelial type II (ATII)-like cells can be generated from murine embryonic stem cells (ESCs), although to date, no robust protocols applying specific differentiation factors are established. We hypothesized that the keratinocyte growth factor (KGF), an important mediator of lung organogenesis and primary ATII cell maturation and proliferation, together with dexamethasone, 8-bromoadenosine-cAMP, and isobutylmethylxanthine (DCI), which induce maturation of primary fetal ATII cells, also support the alveolar differentiation of murine ESCs. Here we demonstrate that the above stimuli synergistically potentiate the alveolar differentiation of ESCs as indicated by increased expression of the surfactant proteins (SP-) C and SP-B. This effect is most profound if KGF is supplied not only in the late stage, but at least also during the intermediate stage of differentiation. Our results indicate that KGF most likely does not enhance the generation of (mes)endodermal or NK2 homeobox 1 (Nkx2.1) expressing progenitor cells but rather, supported by DCI, accelerates further differentiation/maturation of respiratory progeny in the intermediate phase and maturation/proliferation of emerging ATII cells in the late stage of differentiation. Ultrastructural analyses confirmed the presence of ATII-like cells with intracellular composite and lamellar bodies. Finally, induced pluripotent stem cells (iPSCs) were generated from transgenic mice with ATII cell-specific lacZ reporter expression. Again, KGF and DCI synergistically increased SP-C and SP-B expression in iPSC cultures, and lacZ expressing ATII-like cells developed. In conclusion, ATII cell-specific reporter expression enabled the first reliable proof for the generation of murine iPSC-derived ATII cells. In addition, we have shown KGF and DCI to synergistically support the generation of ATII-like cells from ESCs and iPSCs. Combined application of these factors will facilitate more efficient generation of stem cell-derived ATII cells for future basic research and potential therapeutic application.
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Affiliation(s)
- Sabrina Schmeckebier
- Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Department for Cardiothoracic, Transplantation and Vascular Surgery, Hannover Medical School, Hannover, Germany
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35
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Zemans RL, McClendon J, Aschner Y, Briones N, Young SK, Lau LF, Kahn M, Downey GP. Role of β-catenin-regulated CCN matricellular proteins in epithelial repair after inflammatory lung injury. Am J Physiol Lung Cell Mol Physiol 2013; 304:L415-27. [PMID: 23316072 DOI: 10.1152/ajplung.00180.2012] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Repair of the lung epithelium after injury is integral to the pathogenesis and outcomes of diverse inflammatory lung diseases. We previously reported that β-catenin signaling promotes epithelial repair after inflammatory injury, but the β-catenin target genes that mediate this effect are unknown. Herein, we examined which β-catenin transcriptional coactivators and target genes promote epithelial repair after inflammatory injury. Transmigration of human neutrophils across cultured monolayers of human lung epithelial cells resulted in a fall in transepithelial resistance and the formation of discrete areas of epithelial denudation ("microinjury"), which repaired via cell spreading by 96 h. In mice treated with intratracheal (i.t.) LPS or keratinocyte chemokine, neutrophil emigration was associated with increased permeability of the lung epithelium, as determined by increased bronchoalveolar lavage (BAL) fluid albumin concentration, which decreased over 3-6 days. Activation of β-catenin/p300-dependent gene expression using the compound ICG-001 accelerated epithelial repair in vitro and in murine models. Neutrophil transmigration induced epithelial expression of the β-catenin/p300 target genes Wnt-induced secreted protein (WISP) 1 and cysteine-rich (Cyr) 61, as determined by real-time PCR (qPCR) and immunostaining. Purified neutrophil elastase induced WISP1 upregulation in lung epithelial cells, as determined by qPCR. WISP1 expression increased in murine lungs after i.t. LPS, as determined by ELISA of the BAL fluid and qPCR of whole lung extracts. Finally, recombinant WISP1 and Cyr61 accelerated repair, and Cyr61-neutralizing antibodies delayed repair of the injured epithelium in vitro. We conclude that β-catenin/p300-dependent expression of WISP1 and Cyr61 is critical for epithelial repair and represents a potential therapeutic target to promote epithelial repair after inflammatory injury.
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Affiliation(s)
- Rachel L Zemans
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, National Jewish Health, Denver, CO 80206, USA.
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36
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Alphonse RS, Rajabali S, Thébaud B. Lung injury in preterm neonates: the role and therapeutic potential of stem cells. Antioxid Redox Signal 2012; 17:1013-40. [PMID: 22400813 DOI: 10.1089/ars.2011.4267] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Continuous improvements in perinatal care have allowed the survival of ever more premature infants, making the task of protecting the extremely immature lung from injury increasingly challenging. Premature infants at risk of developing chronic lung disease or bronchopulmonary dysplasia (BPD) are now born at the late canalicular stage of lung development, just when the airways become juxtaposed to the lung vasculature and when gas-exchange becomes possible. Readily available strategies, including improved antenatal management (education, regionalization, steroids, and antibiotics), together with exogenous surfactant and exclusive/early noninvasive ventilatory support, will likely decrease the incidence/severity of BPD over the next few years. Nonetheless, because of the extreme immaturity of the developing lung, the extent to which disruption of lung growth after prematurity and neonatal management lead to an earlier or more aggravated decline in respiratory function in later life is a matter of concern. Consequently, much more needs to be learned about the mechanisms of lung development, injury, and repair. Recent insight into stem cell biology has sparked interest for stem cells to repair damaged organs. This review summarizes the exciting potential of stem cell-based therapies for lung diseases in general and BPD in particular.
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37
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Rackley CR, Stripp BR. Building and maintaining the epithelium of the lung. J Clin Invest 2012; 122:2724-30. [PMID: 22850882 DOI: 10.1172/jci60519] [Citation(s) in RCA: 178] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Airspaces of the lung are lined by an epithelium whose cellular composition changes along the proximal-to-distal axis to meet local functional needs for mucociliary clearance, hydration, host defense, and gas exchange. Advances in cell isolation, in vitro culture techniques, and genetic manipulation of animal models have increased our understanding of the development and maintenance of the pulmonary epithelium. This review discusses basic cellular mechanisms that regulate establishment of the conducting airway and gas exchange systems as well as the functional maintenance of the epithelium during postnatal life.
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Affiliation(s)
- Craig R Rackley
- Pulmonary, Allergy and Critical Care, Department of Medicine, Duke University Medical Center, Durham, NC, USA
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Peter Y, Sen N, Levantini E, Keller S, Ingenito EP, Ciner A, Sackstein R, Shapiro SD. CD45/CD11b positive subsets of adult lung anchorage-independent cells harness epithelial stem cells in culture. J Tissue Eng Regen Med 2012; 7:572-83. [PMID: 22585451 DOI: 10.1002/term.553] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2011] [Revised: 08/19/2011] [Accepted: 11/15/2011] [Indexed: 01/02/2023]
Abstract
Compensatory growth is mediated by multiple cell types that interact during organ repair. To elucidate the relationship between stem/progenitor cells that proliferate or differentiate and somatic cells of the lung, we used a novel organotypic ex vivo pneumoexplant system. Applying this technique, we identified a sustained culture of repopulating adult progenitors in the form of free-floating anchorage-independent cells (AICs). AICs did not express integrin proteins α5, β3 and β7, and constituted 37% of the total culture at day 14, yielding a mixed yet conservative population that recapitulated RNA expression patterns of the healthy lung. AICs exhibited rapid proliferation manifested by a marked 60-fold increase in cell numbers by day 21. More than 50% of the AIC population was c-KIT(+) or double-positive for CD45(+) and CD11b(+) antigenic determinants, consistent with cells of hematopoietic origin. The latter subset was found to be enriched with prosurfactant protein-C and SCGB1A1 expressing putative stem cells and with aquaporin-5 producing cells, characteristic of terminally differentiated alveolar epithelial type-1 pneumocytes. At the air/gel interface, AICs undergo remodeling to form a cellular lining, whereas TGF(β)1 treatment modifies protein expression properties to further imply a robust effect of the microenvironment on AIC phenotypic changes. These data confirm the active participation of clonogenic hematopoietic stem cells in a mammalian model of lung repair and validate mixed stem/somatic cell cultures, which license sustained cell viability, proliferation and differentiation, for use in studies of compensatory pulmonary growth.
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Affiliation(s)
- Yakov Peter
- Department of Pulmonary and Critical Care Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Abstract
The majority of epithelial cells in the distal lung of rodents and humans are quiescent in vivo, yet certain cell populations retain an intrinsic capacity to proliferate and differentiate in response to lung injury or in appropriate culture settings, thus giving them properties of stem/progenitor cells. Here, we describe the isolation of two such populations from adult mouse lung: alveolar epithelial type 2 cells (AEC2), which can generate alveolar epithelial type 1 cells, and bronchioalveolar stem cells (BASCs), which in culture can reproduce themselves, as well as generate a small number of other distal lung epithelial cell types. These primary epithelial cells are typically isolated using enzyme digestion, mechanical disruption, and serial filtration. AEC2 and BASCs are distinguished from other distal lung cells by expression of specific markers as detected by fluorescence-activated cell sorting, immunohistochemistry, or a combination of both of these techniques.
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Abstract
The pulmonary alveolar epithelium, comprised of alveolar Type I (TI) and Type II (TII) cells, covers more than 99% of the internal surface area of the lungs. The study of isolated and cultured alveolar epithelial TI and TII cells has provided a large amount of information about the functions of both cell types. This chapter provides information about methods for isolating and culturing both of these cell types from rat lungs.
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41
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Wong MH, Chapin OC, Johnson MD. LPS-stimulated cytokine production in type I cells is modulated by the renin-angiotensin system. Am J Respir Cell Mol Biol 2011; 46:641-50. [PMID: 22205632 DOI: 10.1165/rcmb.2011-0289oc] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The alveolar epithelium serves as a barrier to the entry of potential respiratory pathogens. Alveolar Type II (TII) cells have immunomodulatory functions, but whether Type I (TI) cells, which comprise approximately 95% of the alveolar epithelium, also play a role in immunity is unknown. Because the renin-angiotensin system (RAS) is emerging as an important mediator of inflammation, and angiotensin-converting enzyme 2 (ACE2), an element of the RAS, has been implicated in lung injury, we hypothesize that TI cells can produce cytokines in response to LPS stimulation, and that this inflammation can be modulated by the RAS. Alveolar TI cells were isolated from adult Sprague-Dawley rat lungs that had been injured with an intratracheal instillation of LPS. PCR was performed to determine whether TI cells expressed transcripts for TNF-α, IL-6, or IL-1β at baseline and after lung injury. Immunocytochemical and protein analysis detected angiotensin II (Ang II) and ACE2, as well as angiotensin Type 1 receptor (AT1R) and Type 2 receptor (AT2R), in TI cells. To separate cell-specific responses, primary TI cells were isolated, cultured, and exposed to LPS, Ang II, or specific inhibitors of AT1R or AT2R. Cytokine production was assayed by ELISA. LPS stimulated the production of all cytokines, whereas ACE2 and losartan, an AT1R inhibitor, blocked elements of the LPS-induced cytokine response. Primary TI cells produce cytokines when treated with LPS, contain important components of the RAS, and can modulate LPS-induced cytokine production via the RAS, suggesting a role for TI cells in the innate immune response of the lung.
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Affiliation(s)
- Mandi H Wong
- San Francisco VA Medical Center, 4150 Clement St., San Francisco, CA 94121, USA
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42
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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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43
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Downs CA, Montgomery DW, Merkle CJ. Cell culture models using rat primary alveolar type I cells. Pulm Pharmacol Ther 2011; 24:577-86. [PMID: 21624488 PMCID: PMC3205456 DOI: 10.1016/j.pupt.2011.05.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2010] [Revised: 04/04/2011] [Accepted: 05/14/2011] [Indexed: 11/29/2022]
Abstract
There is a lack of cell culture models using primary alveolar type I (AT I) cells. The purpose of this study was to develop cell culture models using rat AT I cells and microvascular endothelial cells from the lung (MVECL). Two types of model systems were developed: single and co-culture systems; additionally a 3-dimensional model system was developed. Pure AT I cell (96.3 ± 2.7%) and MVECL (97.9 ± 1.1%) preparations were used. AT I cell morphology, mitochondrial number and distribution, actin filament arrangement and number of apoptotic cells at confluence, and telomere attrition were characterized. AT I cells maintained their morphometric characteristics through at least population doubling (PD) 35, while demonstrating telomere attrition through at least PD 100. Furthermore, AT I cells maintained the expression of their specific markers, T1α and AQ-5, through PD 42. For the co-cultures, AT I cells were grown on the top and MVECL were grown on the bottom of fibronectin-coated 24-well Transwell Fluroblok™ filter inserts. Neither cell type transmigrated the 1 μm pores. Additionally, AT I cells were grown in a thick layer of Matrigel(®) to create a 3-dimensional model in which primary AT I cells form ring-like structures that resemble an alveolus. The development of these model systems offers the opportunities to investigate AT I cells and their interactions with MVECL in response to pharmacological interventions and in the processes of disease, repair and regeneration.
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Affiliation(s)
- Charles A. Downs
- The University of Arizona, College of Nursing, Tucson, Arizona
- The Southern Arizona VA HealthCare System, Tucson, Arizona
| | - David W. Montgomery
- The University of Arizona, College of Nursing, Tucson, Arizona
- The Southern Arizona VA HealthCare System, Tucson, Arizona
| | - Carrie J. Merkle
- The University of Arizona, College of Nursing, Tucson, Arizona
- The Southern Arizona VA HealthCare System, Tucson, Arizona
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Crosby LM, Luellen C, Zhang Z, Tague LL, Sinclair SE, Waters CM. Balance of life and death in alveolar epithelial type II cells: proliferation, apoptosis, and the effects of cyclic stretch on wound healing. Am J Physiol Lung Cell Mol Physiol 2011; 301:L536-46. [PMID: 21724858 DOI: 10.1152/ajplung.00371.2010] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
After acute lung injury, repair of the alveolar epithelium occurs on a substrate undergoing cyclic mechanical deformation. While previous studies showed that mechanical stretch increased alveolar epithelial cell necrosis and apoptosis, the impact of cell death during repair was not determined. We examined epithelial repair during cyclic stretch (CS) in a scratch-wound model of primary rat alveolar type II (ATII) cells and found that CS altered the balance between proliferation and cell death. We measured cell migration, size, and density; intercellular gap formation; cell number, proliferation, and apoptosis; cytoskeletal organization; and focal adhesions in response to scratch wounding followed by CS for up to 24 h. Under static conditions, wounds were closed by 24 h, but repair was inhibited by CS. Wounding stimulated cell motility and proliferation, actin and vinculin redistribution, and focal adhesion formation at the wound edge, while CS impeded cell spreading, initiated apoptosis, stimulated cytoskeletal reorganization, and attenuated focal adhesion formation. CS also caused significant intercellular gap formation compared with static cells. Our results suggest that CS alters several mechanisms of epithelial repair and that an imbalance occurs between cell death and proliferation that must be overcome to restore the epithelial barrier.
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Affiliation(s)
- Lynn M Crosby
- Department of Physiology, University of Tennessee Health Science Center, Memphis, USA
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Liu Y, Sadikot RT, Adami GR, Kalinichenko VV, Pendyala S, Natarajan V, Zhao YY, Malik AB. FoxM1 mediates the progenitor function of type II epithelial cells in repairing alveolar injury induced by Pseudomonas aeruginosa. ACTA ACUST UNITED AC 2011; 208:1473-84. [PMID: 21708928 PMCID: PMC3135362 DOI: 10.1084/jem.20102041] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The alveolar epithelium is composed of the flat type I cells comprising 95% of the gas-exchange surface area and cuboidal type II cells comprising the rest. Type II cells are described as facultative progenitor cells based on their ability to proliferate and trans-differentiate into type I cells. In this study, we observed that pneumonia induced by intratracheal instillation of Pseudomonas aeruginosa (PA) in mice increased the expression of the forkhead transcription factor FoxM1 in type II cells coincidentally with the induction of alveolar epithelial barrier repair. FoxM1 was preferentially expressed in the Sca-1(+) subpopulation of progenitor type II cells. In mice lacking FoxM1 specifically in type II cells, type II cells showed decreased proliferation and impaired trans-differentiation into type I cells. Lungs of these mice also displayed defective alveolar barrier repair after injury. Expression of FoxM1 in the knockout mouse lungs partially rescued the defective trans-differentiation phenotype. Thus, expression of FoxM1 in type II cells is essential for their proliferation and transition into type I cells and for restoring alveolar barrier homeostasis after PA-induced lung injury.
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Affiliation(s)
- Yuru Liu
- Department of Pharmacology, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, USA.
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46
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Kubo H. [Acute lung injury/acute respiratory distress syndrome: progress in diagnosis and treatment. Topics: IV. Recent topics: 3. Cell therapy for ARDS]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2011; 100:1613-8. [PMID: 21770287 DOI: 10.2169/naika.100.1613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Hiroshi Kubo
- Department of Advanced Preventive Medicine for Infectious Disease, Tohoku University Graduate School of Medicine, Japan
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47
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Relative efficacy of uptake and presentation of Mycobacterium bovis BCG antigens by type I mouse lung epithelial cells and peritoneal macrophages. Infect Immun 2011; 79:3159-67. [PMID: 21646448 DOI: 10.1128/iai.05406-11] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Flow cytometric studies indicated that both peritoneal macrophages (PMs) and primary lung epithelial (PLE) cells isolated from mouse lungs could take up fluorescence-tagged Mycobacterium bovis BCG. BCG uptake in both cases was significantly inhibited by cytochalasin D, indicating active internalization of BCG by these cells. Confocal microscopy data further confirmed that BCG was internalized by PLE cells. BCG sonicate antigen (sBCG) had marked toxicity toward PMs but was relatively nontoxic to PLE cells. Accordingly, BCG sonicate antigen induced a significantly higher apoptotic and necrotic response in PMs compared to that in PLE cells. Both PMs and PLE cells exposed to BCG antigens and fixed thereafter could efficiently present antigens to purified BCG-sensitized T helper cells, as assessed by the release of interleukin-2 (IL-2) and gamma interferon (IFN-γ). If, however, PLE cells were fixed before exposure to BCG, antigen presentation was abrogated, indicating that the PLE cells may in some way process the BCG antigen. A comparison of efficacies of BCG-pulsed PLE cells and PMs to present antigen at various antigen-presenting cell (APC)/T cell ratios indicated that PMs had only marginally greater APC function than that of PLE cells. Staining with specific monoclonal antibodies indicated that the cultured PLE cells used for antigen presentation essentially comprised type I epithelial cells. Our results suggest that type I lung epithelial cells may present BCG antigens to sensitized T helper cells and that their performance as APCs is comparable with that of PMs.
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48
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MOODLEY Y, MANUELPILLAI U, WEISS DJ. Cellular therapies for lung disease: A distant horizon. Respirology 2011; 16:223-37. [DOI: 10.1111/j.1440-1843.2010.01914.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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49
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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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50
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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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