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Chen GL, Li JY, Chen X, Liu JW, Zhang Q, Liu JY, Wen J, Wang N, Lei M, Wei JP, Yi L, Li JJ, Ling YP, Yi HQ, Hu Z, Duan J, Zhang J, Zeng B. Mechanosensitive channels TMEM63A and TMEM63B mediate lung inflation-induced surfactant secretion. J Clin Invest 2024; 134:e174508. [PMID: 38127458 PMCID: PMC10904053 DOI: 10.1172/jci174508] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Accepted: 12/20/2023] [Indexed: 12/23/2023] Open
Abstract
Pulmonary surfactant is a lipoprotein complex lining the alveolar surface to decrease the surface tension and facilitate inspiration. Surfactant deficiency is often seen in premature infants and in children and adults with respiratory distress syndrome. Mechanical stretch of alveolar type 2 epithelial (AT2) cells during lung expansion is the primary physiological factor that stimulates surfactant secretion; however, it is unclear whether there is a mechanosensor dedicated to this process. Here, we show that loss of the mechanosensitive channels TMEM63A and TMEM63B (TMEM63A/B) resulted in atelectasis and respiratory failure in mice due to a deficit of surfactant secretion. TMEM63A/B were predominantly localized at the limiting membrane of the lamellar body (LB), a lysosome-related organelle that stores pulmonary surfactant and ATP in AT2 cells. Activation of TMEM63A/B channels during cell stretch facilitated the release of surfactant and ATP from LBs fused with the plasma membrane. The released ATP evoked Ca2+ signaling in AT2 cells and potentiated exocytic fusion of more LBs. Our study uncovered a vital physiological function of TMEM63 mechanosensitive channels in preparing the lungs for the first breath at birth and maintaining respiration throughout life.
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Affiliation(s)
- Gui-Lan Chen
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Jing-Yi Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Xin Chen
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Jia-Wei Liu
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Qian Zhang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Jie-Yu Liu
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Jing Wen
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Na Wang
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Ming Lei
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Jun-Peng Wei
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Li Yi
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Jia-Jia Li
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - Yu-Peng Ling
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
| | - He-Qiang Yi
- Department of Cardiothoracic Surgery, The Affiliated Traditional Chinese Medicine Hospital, Southwest Medical University, Luzhou, Sichuan, China
| | - Zhenying Hu
- Human Aging Research Institute and School of Life Sciences and
| | - Jingjing Duan
- Human Aging Research Institute and School of Life Sciences and
| | - Jin Zhang
- School of Basic Medical Sciences, Nanchang University, Nanchang, Jiangxi, China
| | - Bo Zeng
- Key Laboratory of Medical Electrophysiology, Ministry of Education and Medical Electrophysiological Key Laboratory of Sichuan Province, Institute of Cardiovascular Research, and
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2
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Yin X, Vesvoranan O, Andreopoulos F, Dauer EA, Gu W, Huang CYC. Analysis of Extracellular ATP Distribution in the Intervertebral Disc. Ann Biomed Eng 2024; 52:542-555. [PMID: 37934317 DOI: 10.1007/s10439-023-03398-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2023] [Accepted: 10/25/2023] [Indexed: 11/08/2023]
Abstract
Progressive loss of proteoglycans (PGs) is the major biochemical change during intervertebral disc (IVD) degeneration. Adenosine triphosphate (ATP) as the primary energy source is not only critical for cell survival but also serves as a building block in PG synthesis. Extracellular ATP can mediate a variety of physiological functions and was shown to promote extracellular matrix (ECM) production in the IVD. Therefore, the objective of this study was to develop a 3D finite element model to predict extracellular ATP distribution in the IVD and evaluate the impact of degeneration on extracellular ATP distribution. A novel 3D finite element model of the IVD was developed by incorporating experimental measurements of ATP metabolism and ATP-PG binding kinetics into the mechano-electrochemical mixture theory. The new model was validated by experimental data of porcine IVD, and then used to analyze the extracellular distribution of ATP in human IVDs. Extracellular ATP was shown to bind specifically with PGs in IVD ECM. It was found that annulus fibrosus cells hydrolyze ATP faster than that of nucleus pulposus (NP) cells whereas NP cells exhibited a higher ATP release. The distribution of extracellular ATP in a porcine model was consistent with experimental data in our previous study. The predictions from a human IVD model showed a high accumulation of extracellular ATP in the NP region, whereas the extracellular ATP level was reduced with tissue degeneration. This study provides an understanding of extracellular ATP metabolism and its potential biological influences on the IVD via purinergic signaling.
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Affiliation(s)
- Xue Yin
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Oraya Vesvoranan
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Fotios Andreopoulos
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Edward A Dauer
- Department of Biomedical Engineering, University of Miami, Coral Gables, FL, USA
| | - Weiyong Gu
- Department of Mechanical and Aerospace Engineering, University of Miami, Coral Gables, FL, USA
| | - C-Y Charles Huang
- Department of Biomedical Engineering, College of Engineering, University of Miami, P.O. Box 248294, Coral Gables, FL, 33124-0621, USA.
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Hook JL. A role for TMEM63 in the lung. J Clin Invest 2024; 134:e178948. [PMID: 38426500 PMCID: PMC10904035 DOI: 10.1172/jci178948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2024] Open
Abstract
Surfactants are essential for breathing. Although major progress has been made in the past half century toward an understanding of surfactant secretion mechanisms, the identity of the mechanosensor that couples breathing to surfactant secretion has remained elusive. In this issue of the JCI, Chen, Li, and colleagues provide evidence that the mechanosensor is the transmembrane 63 (TMEM63) ion channel. These findings open new avenues for future research into lung mechanobiology.
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Affiliation(s)
- Jaime L. Hook
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine and
- Global Health and Emerging Pathogens Institute, Department of Microbiology, Icahn School of Medicine at Mount Sinai, New York, New York, USA
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4
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Aubin Vega M, Girault A, Meunier É, Chebli J, Privé A, Robichaud A, Adam D, Brochiero E. Function of KvLQT1 potassium channels in a mouse model of bleomycin-induced acute lung injury. Front Physiol 2024; 15:1345488. [PMID: 38444763 PMCID: PMC10912346 DOI: 10.3389/fphys.2024.1345488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Accepted: 01/30/2024] [Indexed: 03/07/2024] Open
Abstract
Acute respiratory distress syndrome (ARDS) is characterized by an exacerbated inflammatory response, severe damage to the alveolar-capillary barrier and a secondary infiltration of protein-rich fluid into the airspaces, ultimately leading to respiratory failure. Resolution of ARDS depends on the ability of the alveolar epithelium to reabsorb lung fluid through active transepithelial ion transport, to control the inflammatory response, and to restore a cohesive and functional epithelium through effective repair processes. Interestingly, several lines of evidence have demonstrated the important role of potassium (K+) channels in the regulation of epithelial repair processes. Furthermore, these channels have previously been shown to be involved in sodium/fluid absorption across alveolar epithelial cells, and we have recently demonstrated the contribution of KvLQT1 channels to the resolution of thiourea-induced pulmonary edema in vivo. The aim of our study was to investigate the role of the KCNQ1 pore-forming subunit of KvLQT1 channels in the outcome of ARDS parameters in a model of acute lung injury (ALI). We used a molecular approach with KvLQT1-KO mice challenged with bleomycin, a well-established ALI model that mimics the key features of the exudative phase of ARDS on day 7. Our data showed that KvLQT1 deletion exacerbated the negative outcome of bleomycin on lung function (resistance, elastance and compliance). An alteration in the profile of infiltrating immune cells was also observed in KvLQT1-KO mice while histological analysis showed less interstitial and/or alveolar inflammatory response induced by bleomycin in KvLQT1-KO mice. Finally, a reduced repair rate of KvLQT1-KO alveolar cells after injury was observed. This work highlights the complex contribution of KvLQT1 in the development and resolution of ARDS parameters in a model of ALI.
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Affiliation(s)
- Mélissa Aubin Vega
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Alban Girault
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
- Laboratoire de Physiologie Cellulaire et Moléculaire (LPCM UR UPJV 4667), Amiens, France
| | - Émilie Meunier
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Jasmine Chebli
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Anik Privé
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
| | | | - Damien Adam
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
| | - Emmanuelle Brochiero
- Centre de recherche du Centre hospitalier de l’Université de Montréal (CRCHUM), Montréal, QC, Canada
- Département de Médecine, Université de Montréal, Montréal, QC, Canada
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Cash E, Goodwin AT, Tatler AL. Adenosine receptor signalling as a driver of pulmonary fibrosis. Pharmacol Ther 2023; 249:108504. [PMID: 37482099 DOI: 10.1016/j.pharmthera.2023.108504] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 06/30/2023] [Accepted: 07/20/2023] [Indexed: 07/25/2023]
Abstract
Pulmonary fibrosis is a debilitating and life-limiting lung condition in which the damage- response mechanisms of mixed-population cells within the lungs go awry. The tissue microenvironment is drastically remodelled by aberrantly activated fibroblasts which deposit ECM components into the surrounding lung tissue, detrimentally affecting lung function and capacity for gas exchange. Growing evidence suggests a role for adenosine signalling in the pathology of tissue fibrosis in a variety of organs, including the lung, but the molecular pathways through which this occurs remain largely unknown. This review explores the role of adenosine in fibrosis and evaluates the contribution of the different adenosine receptors to fibrogenesis. Therapeutic targeting of the adenosine receptors is also considered, along with clinical observations pointing towards a role for adenosine in fibrosis. In addition, the interaction between adenosine signalling and other profibrotic signalling pathways, such as TGFβ1 signalling, is discussed.
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Affiliation(s)
- Emily Cash
- Centre for Respiratory Research, Translational Medical Sciences, School of Medicine, University of Nottingham, UK; NIHR Nottingham Biomedical Research Centre, Nottingham, UK
| | - Amanda T Goodwin
- Centre for Respiratory Research, Translational Medical Sciences, School of Medicine, University of Nottingham, UK; NIHR Nottingham Biomedical Research Centre, Nottingham, UK
| | - Amanda L Tatler
- Centre for Respiratory Research, Translational Medical Sciences, School of Medicine, University of Nottingham, UK; NIHR Nottingham Biomedical Research Centre, Nottingham, UK.
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6
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Wang Y, Singer R, Liu X, Inman SJ, Cao Q, Zhou Q, Noble A, Li L, Arizpe Tafoya AV, Babi M, Ask K, Kolb MR, Ramsay S, Geng F, Zhang B, Shargall Y, Moran-Mirabal JM, Dabaghi M, Hirota JA. The CaT stretcher: An open-source system for delivering uniaxial strain to cells and tissues (CaT). Front Bioeng Biotechnol 2022; 10:959335. [DOI: 10.3389/fbioe.2022.959335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 09/29/2022] [Indexed: 11/13/2022] Open
Abstract
Integration of mechanical cues in conventional 2D or 3D cell culture platforms is an important consideration for in vivo and ex vivo models of lung health and disease. Available commercial and published custom-made devices are frequently limited in breadth of applications, scalability, and customization. Herein we present a technical report on an open-source, cell and tissue (CaT) stretcher, with modularity for different in vitro and ex vivo systems, that includes the following features: 1) Programmability for modeling different breathing patterns, 2) scalability to support low to high-throughput experimentation, and 3) modularity for submerged cell culture, organ-on-chips, hydrogels, and live tissues. The strategy for connecting the experimental cell or tissue samples to the stretching device were designed to ensure that traditional biomedical outcome measurements including, but not limited to microscopy, soluble mediator measurement, and gene and protein expression remained possible. Lastly, to increase the uptake of the device within the community, the system was built with economically feasible and available components. To accommodate diverse in vitro and ex vivo model systems we developed a variety of chips made of compliant polydimethylsiloxane (PDMS) and optimized coating strategies to increase cell adherence and viability during stretch. The CaT stretcher was validated for studying mechanotransduction pathways in lung cells and tissues, with an increase in alpha smooth muscle actin protein following stretch for 24 h observed in independent submerged monolayer, 3D hydrogel, and live lung tissue experiments. We anticipate that the open-source CaT stretcher design will increase accessibility to studies of the dynamic lung microenvironment through direct implementation by other research groups or custom iterations on our designs.
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7
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Vultaggio-Poma V, Falzoni S, Salvi G, Giuliani AL, Di Virgilio F. Signalling by extracellular nucleotides in health and disease. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2022; 1869:119237. [PMID: 35150807 DOI: 10.1016/j.bbamcr.2022.119237] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 02/03/2022] [Accepted: 02/06/2022] [Indexed: 01/04/2023]
Abstract
Nucleotides are released from all cells through regulated pathways or as a result of plasma membrane damage or cell death. Outside the cell, nucleotides act as signalling molecules triggering multiple responses via specific plasma membrane receptors of the P2 family. In the nervous system, purinergic signalling has a key function in neurotransmission. Outside the nervous system, purinergic signalling is one of the major modulators of basal tissue homeostasis, while its dysregulation contributes to the pathogenesis of various disease, including inflammation and cancer. Pre-clinical and clinical evidence shows that selective P2 agonists or antagonists are effective treatments for many pathologies, thus highlighting the relevance of extracellular nucleotides and P2 receptors as therapeutic targets.
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Affiliation(s)
| | | | - Giada Salvi
- Department of Medical Sciences, University of Ferrara, Italy
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8
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Kolb P, Schundner A, Frick M, Gottschalk KE. In Vitro Measurements of Cellular Forces and their Importance in the Lung-From the Sub- to the Multicellular Scale. Life (Basel) 2021; 11:691. [PMID: 34357063 PMCID: PMC8307149 DOI: 10.3390/life11070691] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Revised: 07/09/2021] [Accepted: 07/09/2021] [Indexed: 02/07/2023] Open
Abstract
Throughout life, the body is subjected to various mechanical forces on the organ, tissue, and cellular level. Mechanical stimuli are essential for organ development and function. One organ whose function depends on the tightly connected interplay between mechanical cell properties, biochemical signaling, and external forces is the lung. However, altered mechanical properties or excessive mechanical forces can also drive the onset and progression of severe pulmonary diseases. Characterizing the mechanical properties and forces that affect cell and tissue function is therefore necessary for understanding physiological and pathophysiological mechanisms. In recent years, multiple methods have been developed for cellular force measurements at multiple length scales, from subcellular forces to measuring the collective behavior of heterogeneous cellular networks. In this short review, we give a brief overview of the mechanical forces at play on the cellular level in the lung. We then focus on the technological aspects of measuring cellular forces at many length scales. We describe tools with a subcellular resolution and elaborate measurement techniques for collective multicellular units. Many of the technologies described are by no means restricted to lung research and have already been applied successfully to cells from various other tissues. However, integrating the knowledge gained from these multi-scale measurements in a unifying framework is still a major future challenge.
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Affiliation(s)
- Peter Kolb
- Institute of Experimental Physics, Ulm University, 89069 Ulm, Germany;
| | - Annika Schundner
- Institute of General Physiology, Ulm University, 89069 Ulm, Germany;
| | - Manfred Frick
- Institute of General Physiology, Ulm University, 89069 Ulm, Germany;
| | - Kay-E. Gottschalk
- Institute of Experimental Physics, Ulm University, 89069 Ulm, Germany;
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9
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Lazarowski ER, Boucher RC. Purinergic receptors in airway hydration. Biochem Pharmacol 2021; 187:114387. [PMID: 33358825 DOI: 10.1016/j.bcp.2020.114387] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2020] [Revised: 12/16/2020] [Accepted: 12/17/2020] [Indexed: 02/08/2023]
Abstract
Airway epithelial purinergic receptors control key components of the mucociliary clearance (MCC), the dominant component of pulmonary host defense. In healthy airways, the periciliary liquid (PCL) is optimally hydrated, thus acting as an efficient lubricant layer over which the mucus layer moves by ciliary force. When the hydration of the airway surface decreases, the mucus becomes hyperconcentrated, the PCL collapses, and the "thickened" mucus layer adheres to cell surfaces, causing plaque/plug formation. Mucus accumulation is a major contributing factor to the progression of chronic obstructive lung diseases such as cystic fibrosis (CF) and chronic bronchitis (CB). Mucus hydration is regulated by finely tuned mechanisms of luminal Cl- secretion and Na+ absorption with concomitant osmotically driven water flow. These activities are regulated by airway surface liquid (ASL) concentrations of adenosine and ATP, acting on airway epithelial A2B and P2Y2 receptors, respectively. The goal of this article is to provide an overview of our understanding of the role of purinergic receptors in the regulation of airway epithelial ion/fluid transport and the mechanisms of nucleotide release and metabolic activities that contribute to airway surface hydration in healthy and chronically obstructed airways.
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Affiliation(s)
- Eduardo R Lazarowski
- Marsico Lung Institute/Cystic Fibrosis Center, School of Medicine, University of North Carolina, Chapel Hill, NC, United States.
| | - Richard C Boucher
- Marsico Lung Institute/Cystic Fibrosis Center, School of Medicine, University of North Carolina, Chapel Hill, NC, United States
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10
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Diem K, Fauler M, Fois G, Hellmann A, Winokurow N, Schumacher S, Kranz C, Frick M. Mechanical stretch activates piezo1 in caveolae of alveolar type I cells to trigger ATP release and paracrine stimulation of surfactant secretion from alveolar type II cells. FASEB J 2020; 34:12785-12804. [PMID: 32744386 DOI: 10.1096/fj.202000613rrr] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 12/12/2022]
Abstract
Secretion of pulmonary surfactant in the alveoli of the lungs is essential to maintain lung function. Stretching of alveoli during lung inflation is the main trigger for surfactant secretion. Yet, the molecular mechanisms how mechanical distension of alveoli results in surfactant secretion are still elusive. The alveolar epithelium consists of alveolar epithelial type I (ATI) and surfactant secreting type II (ATII) cells. ATI, but not ATII cells, express caveolae, small plasma membrane invaginations that can respond to plasma membrane stresses and serve mechanotransductive roles. Within this study, we investigated the role of caveolae as mechanosensors in the alveolus. We generated a human caveolin-1 knockout ATI cell (hAELVicav-/- ) using CRISPR/Cas9. Wildtype (hAELViwt ) and hAELVicav-/- cells grown on flexible membranes responded to increasing stretch amplitudes with rises in intracellular Ca2+ . The response was less frequent and started at higher stretch amplitudes in hAELVicav-/- cells. Stretch-induced Ca2+ -signals depended on Ca2+ -entry via piezo1 channels, localized within caveolae in hAELViwt and primary ATI cells. Ca2+ -entry via piezo1 activated pannexin-1 hemichannels resulting in ATP release from ATI cells. ATP release was reduced in hAELVicav-/- cells. In co-cultures resembling the alveolar epithelium, released ATP stimulated Ca2+ signals and surfactant secretion from neighboring ATII cells when co-cultured with hAELViwt but not hAELVicav-/- cells. In summary, we propose that caveolae in ATI cells are mechanosensors within alveoli regulating stretch-induced surfactant secretion from ATII cells.
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Affiliation(s)
- Kathrin Diem
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Michael Fauler
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Giorgio Fois
- Institute of General Physiology, Ulm University, Ulm, Germany
| | - Andreas Hellmann
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | - Natalie Winokurow
- Institute of Molecular and Cellular Anatomy, Ulm University, Ulm, Germany
| | - Stefan Schumacher
- Institute of Molecular and Cellular Anatomy, Ulm University, Ulm, Germany
| | - Christine Kranz
- Institute of Analytical and Bioanalytical Chemistry, Ulm University, Ulm, Germany
| | - Manfred Frick
- Institute of General Physiology, Ulm University, Ulm, Germany
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11
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Wirsching E, Fauler M, Fois G, Frick M. P2 Purinergic Signaling in the Distal Lung in Health and Disease. Int J Mol Sci 2020; 21:E4973. [PMID: 32674494 PMCID: PMC7404078 DOI: 10.3390/ijms21144973] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 07/07/2020] [Accepted: 07/10/2020] [Indexed: 12/13/2022] Open
Abstract
The distal lung provides an intricate structure for gas exchange in mammalian lungs. Efficient gas exchange depends on the functional integrity of lung alveoli. The cells in the alveolar tissue serve various functions to maintain alveolar structure, integrity and homeostasis. Alveolar epithelial cells secrete pulmonary surfactant, regulate the alveolar surface liquid (ASL) volume and, together with resident and infiltrating immune cells, provide a powerful host-defense system against a multitude of particles, microbes and toxicants. It is well established that all of these cells express purinergic P2 receptors and that purinergic signaling plays important roles in maintaining alveolar homeostasis. Therefore, it is not surprising that purinergic signaling also contributes to development and progression of severe pathological conditions like pulmonary inflammation, acute lung injury/acute respiratory distress syndrome (ALI/ARDS) and pulmonary fibrosis. Within this review we focus on the role of P2 purinergic signaling in the distal lung in health and disease. We recapitulate the expression of P2 receptors within the cells in the alveoli, the possible sources of ATP (adenosine triphosphate) within alveoli and the contribution of purinergic signaling to regulation of surfactant secretion, ASL volume and composition, as well as immune homeostasis. Finally, we summarize current knowledge of the role for P2 signaling in infectious pneumonia, ALI/ARDS and idiopathic pulmonary fibrosis (IPF).
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Affiliation(s)
| | | | | | - Manfred Frick
- Institute of General Physiology, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany; (E.W.); (M.F.); (G.F.)
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12
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Analysis of purine receptor expression and functionality in alveolar epithelial cells. Purinergic Signal 2020; 16:213-229. [PMID: 32236789 DOI: 10.1007/s11302-020-09696-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/06/2020] [Indexed: 02/07/2023] Open
Abstract
Despite its fundamental role in providing an extensive surface for gas exchange, the alveolar epithelium (AE) serves as an immunological barrier through, e.g., the release of proinflammatory cytokines and secretion of surfactant to prevent alveolar collapse. Thus, AE is important for sustaining lung homeostasis. Extracellular ATP secreted by alveolar epithelial cells (AECs) is involved in physiological and pathological conditions and acts mainly through the activation of purine receptors (P2Rs). When studying P2R-mediated processes, primary isolated type II AECs (piAECs) still represent the gold standard in in vitro research, although their preparation is time-consuming and requires the sacrifice of many animals. Hence, cultivated immortalized and tumor-derived AEC lines may constitute a valuable alternative. In this work, we examined P2R expression and functionality in piAECs, in immortalized and tumor-derived AEC lines with the purpose of gaining a better understanding of purinergic signaling in different cell systems and assisting researchers in the choice of a suitable cell line with a certain P2R in demand. We combined mRNA and protein analysis to evaluate the expression of P2R. For pharmacological testing, we conducted calcium ([Ca2+]) measurements and siRNA receptor knockdown. Interestingly, the mRNA and protein levels of P2Y2, P2Y6, and P2X4 were detected on all cell lines. Concerning functionality, P2XR could be narrowed to L2 and piAECs while P2YR were active in all cell lines.
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