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Alveal M, Méndez A, García A, Henríquez M. Purinergic regulation of pulmonary vascular tone. Purinergic Signal 2024:10.1007/s11302-024-10010-5. [PMID: 38713328 DOI: 10.1007/s11302-024-10010-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 04/16/2024] [Indexed: 05/08/2024] Open
Abstract
Purinergic signaling is a crucial determinant in the regulation of pulmonary vascular physiology and presents a promising avenue for addressing lung diseases. This intricate signaling system encompasses two primary receptor classes: P1 and P2 receptors. P1 receptors selectively bind adenosine, while P2 receptors exhibit an affinity for ATP, ADP, UTP, and UDP. Functionally, P1 receptors are associated with vasodilation, while P2 receptors mediate vasoconstriction, particularly in basally relaxed vessels, through modulation of intracellular Ca2+ levels. The P2X subtype receptors facilitate extracellular Ca2+ influx, while the P2Y subtype receptors are linked to endoplasmic reticulum Ca2+ release. Notably, the primary receptor responsible for ATP-induced vasoconstriction is P2X1, with α,β-meATP and UDP being identified as potent vasoconstrictor agonists. Interestingly, ATP has been shown to induce endothelium-dependent vasodilation in pre-constricted vessels, associated with nitric oxide (NO) release. In the context of P1 receptors, adenosine stimulation of pulmonary vessels has been unequivocally demonstrated to induce vasodilation, with a clear dependency on the A2B receptor, as evidenced in studies involving guinea pigs and rats. Importantly, evidence strongly suggests that this vasodilation occurs independently of endothelium-mediated mechanisms. Furthermore, studies have revealed variations in the expression of purinergic receptors across different vessel sizes, with reports indicating notably higher expression of P2Y1, P2Y2, and P2Y4 receptors in small pulmonary arteries. While the existing evidence in this area is still emerging, it underscores the urgent need for a comprehensive examination of the specific characteristics of purinergic signaling in the regulation of pulmonary vascular tone, particularly focusing on the disparities observed across different intrapulmonary vessel sizes. Consequently, this review aims to meticulously explore the current evidence regarding the role of purinergic signaling in pulmonary vascular tone regulation, with a specific emphasis on the variations observed in intrapulmonary vessel sizes. This endeavor is critical, as purinergic signaling holds substantial promise in the modulation of vascular tone and in the proactive prevention and treatment of pulmonary vascular diseases.
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Affiliation(s)
- Marco Alveal
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile
| | - Andrea Méndez
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile
- Escuela de Kinesiología, Facultad de Salud y Ciencias Sociales, Campus Providencia, Sede Santiago, Universidad de Las Américas, Santiago, Chile
| | - Aline García
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile
- Escuela de Graduados, Facultad de Ciencias Veterinarias,, Universidad Austral de Chile, Valdivia, Chile
| | - Mauricio Henríquez
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas (ICBM), Facultad de Medicina Universidad de Chile, Independencia 1027, 7500975, Independencia, Santiago, Chile.
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2
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Tang S, De Jesus AC, Chavez D, Suthakaran S, Moore SK, Suthakaran K, Homami S, Rathnasinghe R, May AJ, Schotsaert M, Britto CJ, Bhattacharya J, Hook JL. Rescue of alveolar wall liquid secretion blocks fatal lung injury due to influenza-staphylococcal coinfection. J Clin Invest 2023; 133:e163402. [PMID: 37581936 PMCID: PMC10541650 DOI: 10.1172/jci163402] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/10/2023] [Indexed: 08/17/2023] Open
Abstract
Secondary lung infection by inhaled Staphylococcus aureus (SA) is a common and lethal event for individuals infected with influenza A virus (IAV). How IAV disrupts host defense to promote SA infection in lung alveoli, where fatal lung injury occurs, is not known. We addressed this issue using real-time determinations of alveolar responses to IAV in live, intact, perfused lungs. Our findings show that IAV infection blocked defensive alveolar wall liquid (AWL) secretion and induced airspace liquid absorption, thereby reversing normal alveolar liquid dynamics and inhibiting alveolar clearance of inhaled SA. Loss of AWL secretion resulted from inhibition of the cystic fibrosis transmembrane conductance regulator (CFTR) ion channel in the alveolar epithelium, and airspace liquid absorption was caused by stimulation of the alveolar epithelial Na+ channel (ENaC). Loss of AWL secretion promoted alveolar stabilization of inhaled SA, but rescue of AWL secretion protected against alveolar SA stabilization and fatal SA-induced lung injury in IAV-infected mice. These findings reveal a central role for AWL secretion in alveolar defense against inhaled SA and identify AWL inhibition as a critical mechanism of IAV lung pathogenesis. AWL rescue may represent a new therapeutic approach for IAV-SA coinfection.
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Affiliation(s)
- Stephanie Tang
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
- Graduate School of Biomedical Sciences
| | - Ana Cassandra De Jesus
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Deebly Chavez
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Sayahi Suthakaran
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
- Graduate School of Biomedical Sciences
| | - Sarah K.L. Moore
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Keshon Suthakaran
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
| | - Sonya Homami
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
- Graduate School of Biomedical Sciences
| | - Raveen Rathnasinghe
- Graduate School of Biomedical Sciences
- Global Health and Emerging Pathogens Institute, Department of Microbiology
| | - Alison J. May
- Department of Cell, Developmental and Regenerative Biology
- Department of Otolaryngology, and
- Institute of Regenerative Medicine, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | - Michael Schotsaert
- Global Health and Emerging Pathogens Institute, Department of Microbiology
| | - Clemente J. Britto
- Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jahar Bhattacharya
- Departments of Medicine and Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York, USA
| | - Jaime L. Hook
- Lung Imaging Laboratory, Division of Pulmonary, Critical Care, and Sleep Medicine, Department of Medicine
- Global Health and Emerging Pathogens Institute, Department of Microbiology
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3
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Cusack R, Bos LD, Povoa P, Martin-Loeches I. Endothelial dysfunction triggers acute respiratory distress syndrome in patients with sepsis: a narrative review. Front Med (Lausanne) 2023; 10:1203827. [PMID: 37332755 PMCID: PMC10272540 DOI: 10.3389/fmed.2023.1203827] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2023] [Accepted: 05/16/2023] [Indexed: 06/20/2023] Open
Abstract
Acute respiratory distress syndrome (ARDS) is a severe organ failure occurring mainly in critically ill patients as a result of different types of insults such as sepsis, trauma or aspiration. Sepsis is the main cause of ARDS, and it contributes to a high mortality and resources consumption both in hospital setting and in the community. ARDS develops mainly an acute respiratory failure with severe and often refractory hypoxemia. ARDS also has long term implications and sequelae. Endothelial damage plays an important role in the pathogenesis of ARDS. Understanding the mechanisms of ARDS presents opportunities for novel diagnostic and therapeutic targets. Biochemical signals can be used in concert to identify and classify patients into ARDS phenotypes allowing earlier effective treatment with personalised therapies. This is a narrative review where we aimed to flesh out the pathogenetic mechanisms and heterogeneity of ARDS. We examine the links between endothelium damage and its contribution to organ failure. We have also investigated future strategies for treatment with a special emphasis in endothelial damage.
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Affiliation(s)
- Rachael Cusack
- Department of Intensive Care, St. James’s Hospital, Dublin, Ireland
- School of Medicine, Trinity College Dublin, Dublin, Ireland
| | - Lieuwe D. Bos
- Intensive Care, Amsterdam UMC Location AMC, University of Amsterdam, Amsterdam, Netherlands
| | - Pedro Povoa
- NOVA Medical School, CHRC, New University of Lisbon, Lisbon, Portugal
- Center for Clinical Epidemiology and Research Unit of Clinical Epidemiology, OUH Odense University Hospital, Odense, Denmark
- Department of Intensive Care, Hospital de São Francisco Xavier, CHLO, Lisbon, Portugal
| | - Ignacio Martin-Loeches
- Department of Intensive Care, St. James’s Hospital, Dublin, Ireland
- School of Medicine, Trinity College Dublin, Dublin, Ireland
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4
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Bos LDJ, Ware LB. Acute respiratory distress syndrome: causes, pathophysiology, and phenotypes. Lancet 2022; 400:1145-1156. [PMID: 36070787 DOI: 10.1016/s0140-6736(22)01485-4] [Citation(s) in RCA: 158] [Impact Index Per Article: 79.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 07/14/2022] [Accepted: 07/27/2022] [Indexed: 12/15/2022]
Abstract
Acute respiratory distress syndrome (ARDS) is a common clinical syndrome of acute respiratory failure as a result of diffuse lung inflammation and oedema. ARDS can be precipitated by a variety of causes. The pathophysiology of ARDS is complex and involves the activation and dysregulation of multiple overlapping and interacting pathways of injury, inflammation, and coagulation, both in the lung and systemically. Mechanical ventilation can contribute to a cycle of lung injury and inflammation. Resolution of inflammation is a coordinated process that requires downregulation of proinflammatory pathways and upregulation of anti-inflammatory pathways. The heterogeneity of the clinical syndrome, along with its biology, physiology, and radiology, has increasingly been recognised and incorporated into identification of phenotypes. A precision-medicine approach that improves the identification of more homogeneous ARDS phenotypes should lead to an improved understanding of its pathophysiological mechanisms and how they differ from patient to patient.
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Affiliation(s)
- Lieuwe D J Bos
- Intensive Care, Amsterdam UMC-location AMC, University of Amsterdam, Amsterdam, Netherlands
| | - Lorraine B Ware
- Vanderbilt University School of Medicine, Medical Center North, Vanderbilt University, Nashville, TN, USA.
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5
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Hennigs JK, Lüneburg N, Stage A, Schmitz M, Körbelin J, Harbaum L, Matuszcak C, Mienert J, Bokemeyer C, Böger RH, Kiefmann R, Klose H. The P2-receptor-mediated Ca 2+ signalosome of the human pulmonary endothelium - implications for pulmonary arterial hypertension. Purinergic Signal 2019; 15:299-311. [PMID: 31396838 DOI: 10.1007/s11302-019-09674-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Accepted: 07/18/2019] [Indexed: 02/07/2023] Open
Abstract
Dysfunction of the pulmonary endothelium is associated with most lung diseases. Extracellular nucleotides modulate a plethora of endothelial functions in the lung such as vessel integrity, vasodilatation, inflammatory, and thrombotic responses as well as survival and DNA repair, mostly via Ca2+ signaling pathways. However, a comprehensive analysis of the molecular components of the underlying P2 receptor-mediated Ca2+ signaling pathways in the lung has not been conducted so far. Therefore, our aim was to identify the principal P2 receptor Ca2+ signalosome in the human pulmonary endothelium and investigate potential dysregulation in pulmonary vascular disease. Comparative transcriptomics and quantitative immunohistochemistry were performed on publicly available RNA sequencing and protein datasets to identify the specific expression profile of the P2-receptor Ca2+ signalosome in the healthy human pulmonary endothelium and endothelial cells (EC) dysfunctional due to loss of or defective bone morphogenetic protein receptor (BMPR2). Functional expression of signalosome components was tested by single cell Ca2+ imaging. Comparative transcriptome analysis of 11 endothelial cell subtypes revealed a specific P2 receptor Ca2+ signalosome signature for the pulmonary endothelium. Pulmonary endothelial expression of the most abundantly expressed Ca2+ toolkit genes CALM1, CALM2, VDAC1, and GNAS was confirmed by immunohistochemistry (IHC). P2RX1, P2RX4, P2RY6, and P2YR11 showed strong lung endothelial staining by IHC, P2X5, and P2Y1 were found to a much lesser extent. Very weak or no signals were detected for all other P2 receptors. Stimulation of human pulmonary artery (HPA) EC by purine nucleotides ATP, ADP, and AMP led to robust intracellular Ca2+ signals mediated through both P2X and P2Y receptors. Pyrimidine UTP and UDP-mediated Ca2+ signals were generated almost exclusively by activation of P2Y receptors. HPAEC made dysfunctional by siRNA-mediated BMPR2 depletion showed downregulation of 18 and upregulation of 19 P2 receptor Ca2+ signalosome genes including PLCD4, which was found to be upregulated in iPSC-EC from BMPR2-mutant patients with pulmonary arterial hypertension. In conclusion, the human pulmonary endothelium expresses a distinct functional subset of the P2 receptor Ca2+ signalosome. Composition of the P2 receptor Ca2+ toolkit in the pulmonary endothelium is susceptible to genetic disturbances likely contributing to an unfavorable pulmonary disease phenotype found in pulmonary arterial hypertension.
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Affiliation(s)
- Jan K Hennigs
- Department of Pneumology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany. .,Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany. .,II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.
| | - Nicole Lüneburg
- Institute of Clinical Pharmacology, Center of Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Annett Stage
- Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Institute of Clinical Pharmacology, Center of Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Melanie Schmitz
- Department of Pneumology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Jakob Körbelin
- Department of Pneumology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Lars Harbaum
- Department of Pneumology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Christiane Matuszcak
- Department of Pneumology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Julia Mienert
- Department of Pneumology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Carsten Bokemeyer
- II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Rainer H Böger
- Institute of Clinical Pharmacology, Center of Experimental Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Rainer Kiefmann
- Department of Anesthesiology, Center of Anesthesiology and Critical Care Medicine, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
| | - Hans Klose
- Department of Pneumology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,Center for Pulmonary Arterial Hypertension Hamburg, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany.,II. Department of Internal Medicine, Center of Oncology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246, Hamburg, Germany
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6
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Kiefmann M, Tank S, Tritt MO, Keller P, Heckel K, Schulte-Uentrop L, Olotu C, Schrepfer S, Goetz AE, Kiefmann R. Dead space ventilation promotes alveolar hypocapnia reducing surfactant secretion by altering mitochondrial function. Thorax 2019; 74:219-228. [PMID: 30636196 DOI: 10.1136/thoraxjnl-2018-211864] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/29/2018] [Accepted: 09/10/2018] [Indexed: 11/03/2022]
Abstract
BACKGROUND In acute respiratory distress syndrome (ARDS), pulmonary perfusion failure increases physiologic dead space ventilation (VD/VT), leading to a decline of the alveolar CO2 concentration [CO2]iA. Although it has been shown that alveolar hypocapnia contributes to formation of atelectasis and surfactant depletion, a typical complication in ARDS, the underlying mechanism has not been elucidated so far. METHODS In isolated perfused rat lungs, cytosolic or mitochondrial Ca2+ concentrations ([Ca2+]cyt or [Ca2+]mito, respectively) of alveolar epithelial cells (AECs), surfactant secretion and the projected area of alveoli were quantified by real-time fluorescence or bright-field imaging (n=3-7 per group). In ventilated White New Zealand rabbits, the left pulmonary artery was ligated and the size of subpleural alveoli was measured by intravital microscopy (n=4 per group). Surfactant secretion was determined in the bronchoalveolar lavage (BAL) by western blot. RESULTS Low [CO2]iA decreased [Ca2+]cyt and increased [Ca2+]mito in AECs, leading to reduction of Ca2+-dependent surfactant secretion, and alveolar ventilation in situ. Mitochondrial inhibition by ruthenium red or rotenone blocked these responses indicating that mitochondria are key players in CO2 sensing. Furthermore, ligature of the pulmonary artery of rabbits decreased alveolar ventilation, surfactant secretion and lung compliance in vivo. Addition of 5% CO2 to the inspiratory gas inhibited these responses. CONCLUSIONS Accordingly, we provide evidence that alveolar hypocapnia leads to a Ca2+ shift from the cytosol into mitochondria. The subsequent decline of [Ca2+]cyt reduces surfactant secretion and thus regional ventilation in lung regions with high VD/VT. Additionally, the regional hypoventilation provoked by perfusion failure can be inhibited by inspiratory CO2 application.
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Affiliation(s)
- Martina Kiefmann
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Sascha Tank
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Marc-Oliver Tritt
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Paula Keller
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Kai Heckel
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | | | - Cynthia Olotu
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Sonja Schrepfer
- Division of Adult Cardiothoracic Surgery, University of California San Francisco, San Francisco, California, USA.,Department of Cardiac Surgery, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Alwin E Goetz
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Rainer Kiefmann
- Department of Anesthesiology, University Hospital Hamburg-Eppendorf, Hamburg, Germany
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7
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Preissner M, Murrie RP, Bresee C, Carnibella RP, Fouras A, Weir EK, Dubsky S, Pinar IP, Jones HD. Application of a novel in vivo imaging approach to measure pulmonary vascular responses in mice. Physiol Rep 2018; 6:e13875. [PMID: 30284390 PMCID: PMC6170880 DOI: 10.14814/phy2.13875] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 08/24/2018] [Indexed: 12/19/2022] Open
Abstract
Noninvasive imaging of the murine pulmonary vasculature is challenging due to the small size of the animal, limits of resolution of the imaging technology, terminal nature of the procedure, or the need for intravenous contrast. We report the application of laboratory-based high-speed, high-resolution x-ray imaging, and image analysis to detect quantitative changes in the pulmonary vascular tree over time in the same animal without the need for intravenous contrast. Using this approach, we detected an increased number of vessels in the pulmonary vascular tree of animals after 30 min of recovery from a brief exposure to inspired gas with 10% oxygen plus 5% carbon dioxide (mean ± standard deviation: 2193 ± 382 at baseline vs. 6177 ± 1171 at 30 min of recovery; P < 0.0001). In a separate set of animals, we showed that the total pulmonary blood volume increased (P = 0.0412) while median vascular diameter decreased from 0.20 mm (IQR: 0.15-0.28 mm) to 0.18 mm (IQR: 0.14-0.26 mm; P = 0.0436) over the respiratory cycle from end-expiration to end-inspiration. These findings suggest that the noninvasive, nonintravenous contrast imaging approach reported here can detect dynamic responses of the murine pulmonary vasculature and may be a useful tool in studying these responses in models of disease.
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Affiliation(s)
- Melissa Preissner
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Rhiannon P. Murrie
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Catherine Bresee
- Cedars‐Sinai Medical CenterBiostatistics & Bioinformatics Research InstituteLos AngelesCalifornia
| | | | - Andreas Fouras
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
- 4Dx LimitedMelbourneVictoriaAustralia
- Department of Biomedical SciencesCedars‐Sinai Medical CenterBiomedical Imaging Research InstituteLos AngelesCalifornia
| | - E. Kenneth Weir
- Department of MedicineUniversity of MinnesotaMinneapolisMinnesota
| | - Stephen Dubsky
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Isaac P. Pinar
- Department of Mechanical and Aerospace EngineeringMonash UniversityMelbourneVictoriaAustralia
| | - Heather D. Jones
- Department of Biomedical SciencesCedars‐Sinai Medical CenterBiomedical Imaging Research InstituteLos AngelesCalifornia
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8
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Abstract
Crosstalk signaling between the closely juxtaposed epithelial and endothelial membranes of pulmonary alveoli establishes the lung's immune defense against inhaled and blood-borne pathogens. The crosstalk can occur in a forward direction, as from alveolus to capillary, or in a reverse direction, as from capillary to alveolus. The crosstalk direction likely depends on the site at which pathogens first initiate signaling. Thus, forward crosstalk may occur when inhaled pathogens encounter the alveolar epithelium, while reverse crosstalk may result from interactions of blood-borne pathogens with the endothelium. Here, we review the factors that regulate these two directions of signaling.
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Affiliation(s)
- Rebecca F Hough
- 1 Lung Biology Lab, Columbia University College of Physicians & Surgeons, New York, NY, USA.,2 Department of Pediatrics, Columbia University College of Physicians & Surgeons, New York, NY, USA
| | - Sunita Bhattacharya
- 1 Lung Biology Lab, Columbia University College of Physicians & Surgeons, New York, NY, USA.,2 Department of Pediatrics, Columbia University College of Physicians & Surgeons, New York, NY, USA
| | - Jahar Bhattacharya
- 1 Lung Biology Lab, Columbia University College of Physicians & Surgeons, New York, NY, USA.,3 Department of Medicine, Columbia University College of Physicians & Surgeons, New York, NY, USA
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9
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Huertas A, Guignabert C, Barberà JA, Bärtsch P, Bhattacharya J, Bhattacharya S, Bonsignore MR, Dewachter L, Dinh-Xuan AT, Dorfmüller P, Gladwin MT, Humbert M, Kotsimbos T, Vassilakopoulos T, Sanchez O, Savale L, Testa U, Wilkins MR. Pulmonary vascular endothelium: the orchestra conductor in respiratory diseases. Eur Respir J 2018; 51:13993003.00745-2017. [DOI: 10.1183/13993003.00745-2017] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Accepted: 02/03/2018] [Indexed: 12/15/2022]
Abstract
The European Respiratory Society (ERS) Research Seminar entitled “Pulmonary vascular endothelium: orchestra conductor in respiratory diseases - highlights from basic research to therapy” brought together international experts in dysfunctional pulmonary endothelium, from basic science to translational medicine, to discuss several important aspects in acute and chronic lung diseases. This review will briefly sum up the different topics of discussion from this meeting which was held in Paris, France on October 27–28, 2016. It is important to consider that this paper does not address all aspects of endothelial dysfunction but focuses on specific themes such as: 1) the complex role of the pulmonary endothelium in orchestrating the host response in both health and disease (acute lung injury, chronic obstructive pulmonary disease, high-altitude pulmonary oedema and pulmonary hypertension); and 2) the potential value of dysfunctional pulmonary endothelium as a target for innovative therapies.
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10
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Hook JL, Islam MN, Parker D, Prince AS, Bhattacharya S, Bhattacharya J. Disruption of staphylococcal aggregation protects against lethal lung injury. J Clin Invest 2018; 128:1074-1086. [PMID: 29431734 DOI: 10.1172/jci95823] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Accepted: 01/04/2018] [Indexed: 01/23/2023] Open
Abstract
Infection by Staphylococcus aureus strain USA300 causes tissue injury, multiorgan failure, and high mortality. However, the mechanisms by which the bacteria adhere to, then stabilize on, mucosal surfaces before causing injury remain unclear. We addressed these issues through the first real-time determinations of USA300-alveolar interactions in live lungs. We found that within minutes, inhaled USA300 established stable, self-associated microaggregates in niches at curved, but not at flat, regions of the alveolar wall. The microaggregates released α-hemolysin toxin, causing localized alveolar injury, as indicated by epithelial dye loss, mitochondrial depolarization, and cytosolic Ca2+ increase. Spread of cytosolic Ca2+ through intercellular gap junctions to adjoining, uninfected alveoli caused pulmonary edema. Systemic pretreatment with vancomycin, a USA300-cidal antibiotic, failed to protect mice infected with inhaled WT USA300. However, vancomycin pretreatment markedly abrogated mortality in mice infected with mutant USA300 that lacked the aggregation-promoting factor PhnD. We interpret USA300-induced mortality as having resulted from rapid bacterial aggregation in alveolar niches. These findings indicate, for the first time to our knowledge, that alveolar microanatomy is critical in promoting the aggregation and, hence, in causing USA300-induced alveolar injury. We propose that in addition to antibiotics, strategies for bacterial disaggregation may constitute novel therapy against USA300-induced lung injury.
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Affiliation(s)
- Jaime L Hook
- Lung Biology Laboratory, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | - Mohammad N Islam
- Lung Biology Laboratory, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine
| | | | | | - Sunita Bhattacharya
- Lung Biology Laboratory, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine.,Department of Pediatrics, and
| | - Jahar Bhattacharya
- Lung Biology Laboratory, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine.,Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University Medical Center, New York, New York, USA
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11
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Furuya K, Tan JJ, Boudreault F, Sokabe M, Berthiaume Y, Grygorczyk R. Real-time imaging of inflation-induced ATP release in the ex vivo rat lung. Am J Physiol Lung Cell Mol Physiol 2016; 311:L956-L969. [PMID: 27638905 DOI: 10.1152/ajplung.00425.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 09/13/2016] [Indexed: 12/25/2022] Open
Abstract
Extracellular ATP and other nucleotides are important autocrine/paracrine mediators that regulate diverse processes critical for lung function, including mucociliary clearance, surfactant secretion, and local blood flow. Cellular ATP release is mechanosensitive; however, the impact of physical stimuli on ATP release during breathing has never been tested in intact lungs in real time and remains elusive. In this pilot study, we investigated inflation-induced ATP release in rat lungs ex vivo by real-time luciferin-luciferase (LL) bioluminescence imaging coupled with simultaneous infrared tissue imaging to identify ATP-releasing sites. With LL solution introduced into air spaces, brief inflation of such edematous lung (1 s, ∼20 cmH2O) induced transient (<30 s) ATP release in a limited number of air-inflated alveolar sacs during their recruitment/opening. Released ATP reached concentrations of ∼10-6 M, relevant for autocrine/paracrine signaling, but it remained spatially restricted to single alveolar sacs or their clusters. ATP release was stimulus dependent: prolonged (100 s) inflation evoked long-lasting ATP release that terminated upon alveoli deflation/derecruitment while cyclic inflation/suction produced cyclic ATP release. With LL introduced into blood vessels, inflation induced transient ATP release in many small patchlike areas the size of alveolar sacs. Findings suggest that inflation induces ATP release in both alveoli and the surrounding blood capillary network; the functional units of ATP release presumably consist of alveolar sacs or their clusters. Our study demonstrates the feasibility of real-time ATP release imaging in ex vivo lungs and provides the first direct evidence of inflation-induced ATP release in lung air spaces and in pulmonary blood capillaries, highlighting the importance of purinergic signaling in lung function.
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Affiliation(s)
- Kishio Furuya
- Mechanobiology Laboratory, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Ju Jing Tan
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Francis Boudreault
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada
| | - Masahiro Sokabe
- Mechanobiology Laboratory, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Yves Berthiaume
- Department of Medicine, Université de Montréal, Montreal, Quebec, Canada; and.,Institut de recherches cliniques de Montréal (IRCM), Quebec, Canada
| | - Ryszard Grygorczyk
- Centre de recherche, Centre hospitalier de l'Université de Montréal (CRCHUM), Montreal, Quebec, Canada; .,Department of Medicine, Université de Montréal, Montreal, Quebec, Canada; and
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12
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Henry CO, Dalloneau E, Pérez-Berezo MT, Plata C, Wu Y, Guillon A, Morello E, Aimar RF, Potier-Cartereau M, Esnard F, Coraux C, Börnchen C, Kiefmann R, Vandier C, Touqui L, Valverde MA, Cenac N, Si-Tahar M. In vitro and in vivo evidence for an inflammatory role of the calcium channel TRPV4 in lung epithelium: Potential involvement in cystic fibrosis. Am J Physiol Lung Cell Mol Physiol 2016; 311:L664-75. [PMID: 27496898 DOI: 10.1152/ajplung.00442.2015] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 07/26/2016] [Indexed: 12/22/2022] Open
Abstract
Cystic fibrosis (CF) is an inherited disease associated with chronic severe lung inflammation, leading to premature death. To develop innovative anti-inflammatory treatments, we need to characterize new cellular and molecular components contributing to the mechanisms of lung inflammation. Here, we focused on the potential role of "transient receptor potential vanilloid-4" (TRPV4), a nonselective calcium channel. We used both in vitro and in vivo approaches to demonstrate that TRPV4 expressed in airway epithelial cells triggers the secretion of major proinflammatory mediators such as chemokines and biologically active lipids, as well as a neutrophil recruitment in lung tissues. We characterized the contribution of cytosolic phospholipase A2, MAPKs, and NF-κB in TRPV4-dependent signaling. We also showed that 5,6-, 8,9-, 11,12-, and 14,15-epoxyeicosatrienoic acids, i.e., four natural lipid-based TRPV4 agonists, are present in expectorations of CF patients. Also, TRPV4-induced calcium mobilization and inflammatory responses were enhanced in cystic fibrosis transmembrane conductance regulator-deficient cellular and animal models, suggesting that TRPV4 is a promising target for the development of new anti-inflammatory treatments for diseases such as CF.
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Affiliation(s)
- Clémence O Henry
- Inserm U1100, Centre d'Etude des Pathologies Respiratoires, Tours, France; Université François Rabelais, Tours, France
| | - Emilie Dalloneau
- Inserm U1100, Centre d'Etude des Pathologies Respiratoires, Tours, France; Université François Rabelais, Tours, France
| | - Maria-Teresa Pérez-Berezo
- Centre de Physiopathologie de Toulouse Purpan, Inserm U1043, Toulouse, France; CNRS U5282, Toulouse, France; Université Toulouse III Paul-Sabatier, Toulouse, France
| | - Cristina Plata
- Laboratory of Molecular Physiology and Channelopathies, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Yongzheng Wu
- Unité de Défense Innée et Inflammation, Inserm U874, Institut Pasteur, Paris, France
| | - Antoine Guillon
- Inserm U1100, Centre d'Etude des Pathologies Respiratoires, Tours, France; Université François Rabelais, Tours, France; Service de Réanimation Polyvalente, Centre Hospitalier Régional Universitaire de Tours, Tours, France
| | - Eric Morello
- Inserm U1100, Centre d'Etude des Pathologies Respiratoires, Tours, France; Université François Rabelais, Tours, France
| | - Rose-France Aimar
- Inserm U1100, Centre d'Etude des Pathologies Respiratoires, Tours, France; Université François Rabelais, Tours, France
| | - Marie Potier-Cartereau
- Université François Rabelais, Tours, France; Inserm UMR1069, Nutrition, Croissance et Cancer, Tours, France; Ion Channels and Cancer network-Canceropole Grand Ouest, Tours, France
| | - Frédéric Esnard
- Inserm U1100, Centre d'Etude des Pathologies Respiratoires, Tours, France; Université François Rabelais, Tours, France
| | - Christelle Coraux
- Inserm UMR-S 903, SFR CAP-SANTE (FED 4231), Université de Champagne-Ardenne, Reims, France
| | - Christian Börnchen
- Cardiovascular Research Center Hamburg and German Center for Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and Department of Anaesthesiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rainer Kiefmann
- Cardiovascular Research Center Hamburg and German Center for Cardiovascular Research, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; and Department of Anaesthesiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Christophe Vandier
- Université François Rabelais, Tours, France; Inserm UMR1069, Nutrition, Croissance et Cancer, Tours, France; Ion Channels and Cancer network-Canceropole Grand Ouest, Tours, France
| | - Lhousseine Touqui
- Unité de Défense Innée et Inflammation, Inserm U874, Institut Pasteur, Paris, France
| | - Miguel A Valverde
- Laboratory of Molecular Physiology and Channelopathies, Department of Experimental and Health Sciences, Universitat Pompeu Fabra, Barcelona, Spain
| | - Nicolas Cenac
- Centre de Physiopathologie de Toulouse Purpan, Inserm U1043, Toulouse, France; CNRS U5282, Toulouse, France; Université Toulouse III Paul-Sabatier, Toulouse, France
| | - Mustapha Si-Tahar
- Inserm U1100, Centre d'Etude des Pathologies Respiratoires, Tours, France; Université François Rabelais, Tours, France;
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13
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Kirby PL, Buerk DG, Parikh J, Barbee KA, Jaron D. Mathematical model for shear stress dependent NO and adenine nucleotide production from endothelial cells. Nitric Oxide 2016; 52:1-15. [PMID: 26529478 PMCID: PMC4703509 DOI: 10.1016/j.niox.2015.10.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 10/21/2015] [Accepted: 10/27/2015] [Indexed: 11/19/2022]
Abstract
We developed a mass transport model for a parallel-plate flow chamber apparatus to predict the concentrations of nitric oxide (NO) and adenine nucleotides (ATP, ADP) produced by cultured endothelial cells (ECs) and investigated how the net rates of production, degradation, and mass transport for these three chemical species vary with changes in wall shear stress (τw). These simulations provide an improved understanding of experimental results obtained with parallel-plate flow chambers and allows quantitative analysis of the relationship between τw, adenine nucleotide concentrations, and NO produced by ECs. Experimental data obtained after altering ATP and ADP concentrations with apyrase were analyzed to quantify changes in the rate of NO production (RNO). The effects of different isoforms of apyrase on ATP and ADP concentrations and nucleotide-dependent changes in RNO could be predicted with the model. A decrease in ATP was predicted with apyrase, but an increase in ADP was simulated due to degradation of ATP. We found that a simple proportional relationship relating a component of RNO to the sum of ATP and ADP provided a close match to the fitted curve for experimentally measured changes in RNO with apyrase. Estimates for the proportionality constant ranged from 0.0067 to 0.0321 μM/s increase in RNO per nM nucleotide concentration, depending on which isoform of apyrase was modeled, with the largest effect of nucleotides on RNO at low τw (<6 dyn/cm(2)).
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Affiliation(s)
- Patrick L Kirby
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA
| | - Donald G Buerk
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA
| | - Jaimit Parikh
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA
| | - Kenneth A Barbee
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA
| | - Dov Jaron
- School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, PA 19104, USA.
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14
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Ito S, Furuya K, Sokabe M, Hasegawa Y. Cellular ATP release in the lung and airway. AIMS BIOPHYSICS 2016. [DOI: 10.3934/biophy.2016.4.571] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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15
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Mehta D, Ravindran K, Kuebler WM. Novel regulators of endothelial barrier function. Am J Physiol Lung Cell Mol Physiol 2014; 307:L924-35. [PMID: 25381026 PMCID: PMC4269690 DOI: 10.1152/ajplung.00318.2014] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 11/05/2014] [Indexed: 12/15/2022] Open
Abstract
Endothelial barrier function is an essential and tightly regulated process that ensures proper compartmentalization of the vascular and interstitial space, while allowing for the diffusive exchange of small molecules and the controlled trafficking of macromolecules and immune cells. Failure to control endothelial barrier integrity results in excessive leakage of fluid and proteins from the vasculature that can rapidly become fatal in scenarios such as sepsis or the acute respiratory distress syndrome. Here, we highlight recent advances in our understanding on the regulation of endothelial permeability, with a specific focus on the endothelial glycocalyx and endothelial scaffolds, regulatory intracellular signaling cascades, as well as triggers and mediators that either disrupt or enhance endothelial barrier integrity, and provide our perspective as to areas of seeming controversy and knowledge gaps, respectively.
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Affiliation(s)
- Dolly Mehta
- Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois at Chicago, Chicago, Illinois;
| | - Krishnan Ravindran
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
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16
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P2X7 receptor polymorphisms do not influence endothelial function and vascular tone in neo-diagnosed, treatment-naive essential hypertensive patients. J Hypertens 2013; 31:2362-9. [DOI: 10.1097/hjh.0b013e3283653ff5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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17
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Abstract
Mechanical ventilation (MV) is, by definition, the application of external forces to the lungs. Depending on their magnitude, these forces can cause a continuum of pathophysiological alterations ranging from the stimulation of inflammation to the disruption of cell-cell contacts and cell membranes. These side effects of MV are particularly relevant for patients with inhomogeneously injured lungs such as in acute lung injury (ALI). These patients require supraphysiological ventilation pressures to guarantee even the most modest gas exchange. In this situation, ventilation causes additional strain by overdistension of the yet non-injured region, and additional stress that forms because of the interdependence between intact and atelectatic areas. Cells are equipped with elaborate mechanotransduction machineries that respond to strain and stress by the activation of inflammation and repair mechanisms. Inflammation is the fundamental response of the host to external assaults, be they of mechanical or of microbial origin and can, if excessive, injure the parenchymal tissue leading to ALI. Here, we will discuss the forces generated by MV and how they may injure the lungs mechanically and through inflammation. We will give an overview of the mechanotransduction and how it leads to inflammation and review studies demonstrating that ventilator-induced lung injury can be prevented by blocking pathways of mechanotransduction or inflammation.
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Affiliation(s)
- Ulrike Uhlig
- Department of Pharmacology & Toxicology, Medical Faculty, RWTH Aachen University, Aachen, Germany
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18
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Abstract
Live lung imaging has spanned the discovery of capillaries in the frog lung by Malpighi to the current use of single and multiphoton imaging of intravital and isolated perfused lung preparations incorporating fluorescent molecular probes and transgenic reporter mice. Along the way, much has been learned about the unique microcirculation of the lung, including immune cell migration and the mechanisms by which cells at the alveolar-capillary interface communicate with each other. In this review, we highlight live lung imaging techniques as applied to the role of mitochondria in lung immunity, mechanisms of signal transduction in lung compartments, studies on the composition of alveolar wall liquid, and neutrophil and platelet trafficking in the lung under homeostatic and inflammatory conditions. New applications of live lung imaging and the limitations of current techniques are discussed.
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Affiliation(s)
- Mark R. Looney
- Departments of Medicine and Laboratory Medicine, University of California, San Francisco, California 94143
| | - Jahar Bhattacharya
- Division of Pulmonary Allergy and Critical Care, Department of Medicine, and Department of Physiology & Cellular Biophysics, Columbia University College of Physicians & Surgeons, New York, New York 10032
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19
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Islam MN, Gusarova GA, Monma E, Das SR, Bhattacharya J. F-actin scaffold stabilizes lamellar bodies during surfactant secretion. Am J Physiol Lung Cell Mol Physiol 2013; 306:L50-7. [PMID: 24213916 DOI: 10.1152/ajplung.00252.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Alveolar type 2 (AT2) cells secrete surfactant that forms a protective layer on the lung's alveolar epithelium. Vesicles called lamellar bodies (LBs) store surfactant. Failure of surfactant secretion, which causes severe lung disease, relates to the manner in which LBs undergo exocytosis during the secretion. However, the dynamics of LBs during the secretion process are not known in intact alveoli. Here, we addressed this question through real-time confocal microscopy of single AT2 cells in live alveoli of mouse lungs. Using a combination of phospholipid and aqueous fluorophores that localize to LBs, we induced surfactant secretion by transiently hyperinflating the lung, and we quantified the secretion in terms of loss of bulk LB fluorescence. In addition, we quantified inter-LB phospholipid flow through determinations of fluorescence recovery after photobleaching. Furthermore, we determined the role of F-actin in surfactant secretion through expression of the fluorescent F-actin probe Lifeact. Our findings indicate that, in AT2 cells in situ, LBs are held in an F-actin scaffold. Although F-actin transiently decreases during surfactant secretion, the LBs remain stationary, forming a chain of vesicles connected by intervesicular channels that convey surfactant to the secretion site on the plasma membrane. This is the first instance of a secretory process in which the secretory vesicles are immobile, but form a conduit for the secretory material.
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20
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Lipopolysaccharide induces endoplasmic store Ca2+-dependent inflammatory responses in lung microvessels. PLoS One 2013; 8:e63465. [PMID: 23675486 PMCID: PMC3651233 DOI: 10.1371/journal.pone.0063465] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2013] [Accepted: 04/03/2013] [Indexed: 01/06/2023] Open
Abstract
The pulmonary microvasculature plays a critical role in endotoxin-induced acute lung injury. However, the relevant signaling remain unclear. Specifically the role of endothelial Ca2+ in the induction of endotoxin-mediated responses in lung microvessels remains undefined. Toward elucidating this, we used the isolated blood-perfused rat lung preparation. We loaded microvessels with the Ca2+ indicator, Fura 2 AM and then determined Ca2+ responses to infusions of lipopolysaccharide (LPS) into the microvessels. LPS induced a more than two-fold increase in the amplitude of cytosolic Ca2+ oscillations. Inhibiting inositol 1,4,5 trisphosphate receptors on endoplasmic reticulum (ER) Ca2+ stores with Xestospongin C (XeC), blocked the LPS-induced increase in the Ca2+ oscillation amplitude. However, XeC did not affect entry of external Ca2+ via plasma membrane Ca2+ channels in lung microvascular endothelial cells. This suggested that LPS augmented the oscillations via release of Ca2+ from ER stores. In addition, XeC also blocked LPS-mediated activation and nuclear translocation of nuclear factor-kappa B in lung microvessels. Further, inhibiting ER Ca2+ release blunted increases in intercellular adhesion molecule-1 expression and retention of naïve leukocytes in LPS-treated microvessels. Taken together, the data suggest that LPS-mediated Ca2+ release from ER stores underlies nuclear factor-kappa B activation and downstream inflammatory signaling in lung microvessels. Thus, we show for the first time a role for inositol 1,4,5 trisphosphate-mediated ER Ca2+ release in the induction of LPS responses in pulmonary microvascular endothelium. Mechanisms that blunt this signaling may mitigate endotoxin-induced morbidity.
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21
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Burnstock G, Brouns I, Adriaensen D, Timmermans JP. Purinergic signaling in the airways. Pharmacol Rev 2012; 64:834-68. [PMID: 22885703 DOI: 10.1124/pr.111.005389] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Evidence for a significant role and impact of purinergic signaling in normal and diseased airways is now beyond dispute. The present review intends to provide the current state of knowledge of the involvement of purinergic pathways in the upper and lower airways and lungs, thereby differentiating the involvement of different tissues, such as the epithelial lining, immune cells, airway smooth muscle, vasculature, peripheral and central innervation, and neuroendocrine system. In addition to the vast number of well illustrated functions for purinergic signaling in the healthy respiratory tract, increasing data pointing to enhanced levels of ATP and/or adenosine in airway secretions of patients with airway damage and respiratory diseases corroborates the emerging view that purines act as clinically important mediators resulting in either proinflammatory or protective responses. Purinergic signaling has been implicated in lung injury and in the pathogenesis of a wide range of respiratory disorders and diseases, including asthma, chronic obstructive pulmonary disease, inflammation, cystic fibrosis, lung cancer, and pulmonary hypertension. These ostensibly enigmatic actions are based on widely different mechanisms, which are influenced by the cellular microenvironment, but especially the subtypes of purine receptors involved and the activity of distinct members of the ectonucleotidase family, the latter being potential protein targets for therapeutic implementation.
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Affiliation(s)
- Geoffrey Burnstock
- Autonomic Neuroscience Centre, University College Medical School, Royal Free Campus, London, UK.
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22
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Parthasarathi K. Endothelial connexin43 mediates acid-induced increases in pulmonary microvascular permeability. Am J Physiol Lung Cell Mol Physiol 2012; 303:L33-42. [PMID: 22561459 DOI: 10.1152/ajplung.00219.2011] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Acid aspiration, a common cause of acute lung injury, leads to alveolar edema. Increase in lung vascular permeability underlies this pathology. To define mechanisms, isolated rat lungs were perfused with autologous blood. Hydrochloric acid and rhodamine-dextran 70 kDa (RDx70) were coinstilled into an alveolus by micropuncture. RDx70 fluorescence was used to establish the spatial distribution of acid. Subsequently, FITC-dextran 20 kDa (FDx20) was infused into microvessels for 60 min followed by a 10-min HEPES-buffered saline wash. During the infusion, FITC fluorescence changes were recorded to quantify the ratio of peak to postwash fluorescence. The ratio, termed normalized fluorescence, was low for acid compared with buffer instillation both in microvessels abutting acid-treated alveoli and those located more than 700 μm away. In contrast, the normalized fluorescence was similar to buffer controls when a higher molecular weight tracer (FITC-dextran 70 kDa) was infused instead of FDx20, suggesting that normalized FDx20 fluorescence faithfully represented microvascular permeability. Inhibiting endothelial connexin43 (Cx43) gap junction communication with Gap27 blunted the acid-induced reduction in normalized fluorescence, although scrambled Gap27 did not have any effect. The blunting was evident not only in microvessels away from the site of injury, but also in those abutting directly injured alveoli. Thus the new fluorescence-based method reveals that acid increases microvascular permeability both at acid-instilled and away sites. Inhibiting endothelial Cx43 blocked the permeability increase even at the direct injury sites. These data indicate for the first time that Cx43-dependent mechanisms mediate acid-induced increases in microvascular permeability. Cx43 may be a therapeutic target in acid injury.
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23
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Rose JE, Dehkordi O, Fatemi M, Raghupathi R, Millis RM, Jayam-Trouth A. Neuroanatomical evidence for a putative autocrine/paracrine signaling system involving nicotinic acetylcholine receptors, purinergic receptors, and nitric oxide synthase in the airways. J Neurosci Res 2011; 90:849-59. [DOI: 10.1002/jnr.22817] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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The role of purinergic signaling on deformation induced injury and repair responses of alveolar epithelial cells. PLoS One 2011; 6:e27469. [PMID: 22087324 PMCID: PMC3210789 DOI: 10.1371/journal.pone.0027469] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Accepted: 10/17/2011] [Indexed: 01/11/2023] Open
Abstract
Cell wounding is an important driver of the innate immune response of ventilator-injured lungs. We had previously shown that the majority of wounded alveolus resident cells repair and survive deformation induced insults. This is important insofar as wounded and repaired cells may contribute to injurious deformation responses commonly referred to as biotrauma. The central hypothesis of this communication states that extracellular adenosine-5′ triphosphate (ATP) promotes the repair of wounded alveolus resident cells by a P2Y2-Receptor dependent mechanism. Using primary type 1 alveolar epithelial rat cell models subjected to micropuncture injury and/or deforming stress we show that 1) stretch causes a dose dependent increase in cell injury and ATP media concentrations; 2) enzymatic depletion of extracellular ATP reduces the probability of stretch induced wound repair; 3) enriching extracellular ATP concentrations facilitates wound repair; 4) purinergic effects on cell repair are mediated by ATP and not by one of its metabolites; and 5) ATP mediated cell salvage depends at least in part on P2Y2-R activation. While rescuing cells from wounding induced death may seem appealing, it is possible that survivors of membrane wounding become governors of a sustained pro-inflammatory state and thereby perpetuate and worsen organ function in the early stages of lung injury syndromes. Means to uncouple P2Y2-R mediated cytoprotection from P2Y2-R mediated inflammation and to test the preclinical efficacy of such an undertaking deserve to be explored.
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25
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Koval M, Billaud M, Straub AC, Johnstone SR, Zarbock A, Duling BR, Isakson BE. Spontaneous lung dysfunction and fibrosis in mice lacking connexin 40 and endothelial cell connexin 43. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 178:2536-46. [PMID: 21641379 PMCID: PMC3124229 DOI: 10.1016/j.ajpath.2011.02.045] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2010] [Revised: 12/30/2010] [Accepted: 02/01/2011] [Indexed: 12/31/2022]
Abstract
Gap junction proteins (connexins) facilitate intercellular communication and serve several roles in regulation of tissue function and remodeling. To examine the physiologic effects of depleting two prominent endothelial connexins, Cx40 and Cx43, transgenic mice were generated by breeding Cx40-deficient mice (Cx40(-/-)) with a vascular endothelial cell (VEC)-specific Cx43-deficient mouse strain (VEC Cx43(-/-)) to produce double-connexin knockout mice (VEC Cx43(-/-)/Cx40(-/-)). The life span in VEC Cx43(-/-)/Cx40(-/-) mice was dramatically shortened, which correlated with severe spontaneous lung abnormalities as the mice aged including increased fibrosis, aberrant alveolar remodeling, and increased lung fibroblast content. Moreover, VEC Cx43(-/-)/Cx40(-/-) mice exhibited cardiac hypertrophy and hypertension. Because VEC Cx43(-/-)/Cx40(-/-) mice demonstrated phenotypic hallmarks that were remarkably similar to those in mice deficient in caveolin-1, pulmonary caveolin expression was examined. Lungs from VEC Cx43(-/-)/Cx40(-/-) mice demonstrated significantly decreased expression of caveolin-1 and caveolin-2. This suggests that expression of caveolin-1 may be linked to expression of Cx40 and endothelial Cx43. Moreover, the phenotype of caveolin-1(-/-) mice and VEC Cx43(-/-)/Cx40(-/-) mice may arise via a common mechanism.
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Affiliation(s)
- Michael Koval
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Emory University School of Medicine, Atlanta, Georgia
- Department of Cell Biology, Emory University School of Medicine, Atlanta, Georgia
| | - Marie Billaud
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Adam C. Straub
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Scott R. Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Alexander Zarbock
- Department of Anesthesiology and Critical Care Medicine, University of Münster, Münster, Germany
- Max-Planck-Institute of Molecular Biomedicine, Münster, Germany
| | - Brian R. Duling
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Brant E. Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
- Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, Virginia
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Rowlands DJ, Islam MN, Das SR, Huertas A, Quadri SK, Horiuchi K, Inamdar N, Emin MT, Lindert J, Ten VS, Bhattacharya S, Bhattacharya J. Activation of TNFR1 ectodomain shedding by mitochondrial Ca2+ determines the severity of inflammation in mouse lung microvessels. J Clin Invest 2011; 121:1986-99. [PMID: 21519143 DOI: 10.1172/jci43839] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Accepted: 02/09/2011] [Indexed: 12/25/2022] Open
Abstract
Shedding of the extracellular domain of cytokine receptors allows the diffusion of soluble receptors into the extracellular space; these then bind and neutralize their cytokine ligands, thus dampening inflammatory responses. The molecular mechanisms that control this process, and the extent to which shedding regulates cytokine-induced microvascular inflammation, are not well defined. Here, we used real-time confocal microscopy of mouse lung microvascular endothelium to demonstrate that mitochondria are key regulators of this process. The proinflammatory cytokine soluble TNF-α (sTNF-α) increased mitochondrial Ca2+, and the purinergic receptor P2Y2 prolonged the response. Concomitantly, the proinflammatory receptor TNF-α receptor-1 (TNFR1) was shed from the endothelial surface. Inhibiting the mitochondrial Ca2+ increase blocked the shedding and augmented inflammation, as denoted by increases in endothelial expression of the leukocyte adhesion receptor E-selectin and in microvascular leukocyte recruitment. The shedding was also blocked in microvessels after knockdown of a complex III component and after mitochondria-targeted catalase overexpression. Endothelial deletion of the TNF-α converting enzyme (TACE) prevented the TNF-α receptor shedding response, which suggests that exposure of microvascular endothelium to sTNF-α induced a Ca2+-dependent increase of mitochondrial H2O2 that caused TNFR1 shedding through TACE activation. These findings provide what we believe to be the first evidence that endothelial mitochondria regulate TNFR1 shedding and thereby determine the severity of sTNF-α-induced microvascular inflammation.
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Affiliation(s)
- David J Rowlands
- Lung Biology Laboratory, Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, Columbia University College of Physicians and Surgeons, New York, New York, USA
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Bove PF, Grubb BR, Okada SF, Ribeiro CMP, Rogers TD, Randell SH, O'Neal WK, Boucher RC. Human alveolar type II cells secrete and absorb liquid in response to local nucleotide signaling. J Biol Chem 2010; 285:34939-49. [PMID: 20801871 PMCID: PMC2966108 DOI: 10.1074/jbc.m110.162933] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2010] [Revised: 08/23/2010] [Indexed: 12/21/2022] Open
Abstract
A balance sheet describing the integrated homeostasis of secretion, absorption, and surface movement of liquids on pulmonary surfaces has remained elusive. It remains unclear whether the alveolus exhibits an intra-alveolar ion/liquid transport physiology or whether it secretes ions/liquid that may communicate with airway surfaces. Studies employing isolated human alveolar type II (AT2) cells were utilized to investigate this question. Human AT2 cells exhibited both epithelial Na(+) channel-mediated Na(+) absorption and cystic fibrosis transmembrane conductance regulator-mediated Cl(-) secretion, both significantly regulated by extracellular nucleotides. In addition, we observed in normal AT2 cells an absence of cystic fibrosis transmembrane conductance regulator regulation of epithelial Na(+) channel activity and an absence of expression/activity of reported calcium-activated chloride channels (TMEM16A, Bestrophin-1, ClC2, and SLC26A9), both features strikingly different from normal airway epithelial cells. Measurements of alveolar surface liquid volume revealed that normal AT2 cells: 1) achieved an extracellular nucleotide concentration-dependent steady state alveolar surface liquid height of ∼4 μm in vitro; 2) absorbed liquid when the lumen was flooded; and 3) secreted liquid when treated with UTP or forskolin or subjected to cyclic compressive stresses mimicking tidal breathing. Collectively, our studies suggest that human AT2 cells in vitro have the capacity to absorb or secrete liquid in response to local alveolar conditions.
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Affiliation(s)
- Peter F. Bove
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Barbara R. Grubb
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Seiko F. Okada
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Carla M. P. Ribeiro
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Troy D. Rogers
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Scott H. Randell
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Wanda K. O'Neal
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
| | - Richard C. Boucher
- From the Department of Medicine, Cystic Fibrosis/Pulmonary Research and Treatment Center, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599
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Lyubchenko T, Woodward H, Veo KD, Burns N, Nijmeh H, Liubchenko GA, Stenmark KR, Gerasimovskaya EV. P2Y1 and P2Y13 purinergic receptors mediate Ca2+ signaling and proliferative responses in pulmonary artery vasa vasorum endothelial cells. Am J Physiol Cell Physiol 2010; 300:C266-75. [PMID: 20962269 DOI: 10.1152/ajpcell.00237.2010] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Extracellular ATP and ADP have been shown to exhibit potent angiogenic effects on pulmonary artery adventitial vasa vasorum endothelial cells (VVEC). However, the molecular signaling mechanisms of extracellular nucleotide-mediated angiogenesis remain not fully elucidated. Since elevation of intracellular Ca(2+) concentration ([Ca(2+)](i)) is required for cell proliferation and occurs in response to extracellular nucleotides, this study was undertaken to delineate the purinergic receptor subtypes involved in Ca(2+) signaling and extracellular nucleotide-mediated mitogenic responses in VVEC. Our data indicate that stimulation of VVEC with extracellular ATP resulted in the elevation of [Ca(2+)](i) via Ca(2+) influx through plasma membrane channels as well as Ca(2+) mobilization from intracellular stores. Moreover, extracellular ATP induced simultaneous Ca(2+) responses in both cytosolic and nuclear compartments. An increase in [Ca(2+)](i) was observed in response to a wide range of purinergic receptor agonists, including ATP, ADP, ATPγS, ADPβS, UTP, UDP, 2-methylthio-ATP (MeSATP), 2-methylthio-ADP (MeSADP), and BzATP, but not adenosine, AMP, diadenosine tetraphosphate, αβMeATP, and βγMeATP. Using RT-PCR, we identified mRNA for the P2Y1, P2Y2, P2Y4, P2Y13, P2Y14, P2X2, P2X5, P2X7, A1, A2b, and A3 purinergic receptors in VVEC. Preincubation of VVEC with the P2Y1 selective antagonist MRS2179 and the P2Y13 selective antagonist MRS2211, as well as with pertussis toxin, attenuated at varying degrees agonist-induced intracellular Ca(2+) responses and activation of ERK1/2, Akt, and S6 ribosomal protein, indicating that P2Y1 and P2Y13 receptors play a major role in VVEC growth responses. Considering the broad physiological implications of purinergic signaling in the regulation of angiogenesis and vascular homeostasis, our findings suggest that P2Y1 and P2Y13 receptors may represent novel and specific targets for treatment of pathological vascular remodeling involving vasa vasorum expansion.
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Affiliation(s)
- Taras Lyubchenko
- Dept. of Pediatrics, University of Colorado Denver, Research 2, Box B131, Aurora, CO 80045, USA
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Dassow C, Wiechert L, Martin C, Schumann S, Müller-Newen G, Pack O, Guttmann J, Wall WA, Uhlig S. Biaxial distension of precision-cut lung slices. J Appl Physiol (1985) 2010; 108:713-21. [PMID: 20075265 DOI: 10.1152/japplphysiol.00229.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanical forces acting on lung parenchyma during (mechanical) ventilation and its (patho)physiological consequences are currently under intense scrutiny. Several in vivo and cell culture models have been developed to study the pulmonary responses to mechanical stretch. While providing extremely useful information, these models do also suffer from limitations in being either too complex for detailed mechanical or mechanistic studies, or in being devoid of the full complexity present in vivo (e.g., different cell types and interstitial matrix). Therefore in the present study it was our aim to develop a new model, based on the biaxial stretching of precision-cut lung slices (PCLS). Single PCLS were mounted on a thin and flexible carrier membrane of polydimethylsiloxane (PDMS) in a bioreactor, and the membrane was stretched by applying varying pressures under static conditions. Distension of the membrane-PCLS construct was modeled via finite element simulation. According to this analysis, lung tissue was stretched by up to 38% in the latitudinal and by up to 44% in the longitudinal direction, resulting in alveolar distension similar to what has been described in intact lungs. Stretch for 5 min led to increased cellular calcium levels. Lung slices were stretched dynamically with a frequency of 15/min for 4 h without causing cell injury {3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) test; live/dead straining}. These findings suggest that stretching of PCLS on PDMS-membranes may represent a useful model to investigate lung stretch in intact lung tissue in vitro for several hours.
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Affiliation(s)
- C Dassow
- Institute of Pharmacology and Toxicology, Medical Faculty, RWTH Aachen University, Wendlingweg 2, 52074 Aachen, Germany
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Corriden R, Insel PA. Basal release of ATP: an autocrine-paracrine mechanism for cell regulation. Sci Signal 2010; 3:re1. [PMID: 20068232 DOI: 10.1126/scisignal.3104re1] [Citation(s) in RCA: 263] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Cells release adenosine triphosphate (ATP), which activates plasma membrane-localized P2X and P2Y receptors and thereby modulates cellular function in an autocrine or paracrine manner. Release of ATP and the subsequent activation of P2 receptors help establish the basal level of activation (sometimes termed "the set point") for signal transduction pathways and regulate a wide array of responses that include tissue blood flow, ion transport, cell volume regulation, neuronal signaling, and host-pathogen interactions. Basal release and autocrine or paracrine responses to ATP are multifunctional, evolutionarily conserved, and provide an economical means for the modulation of cell, tissue, and organismal biology.
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Affiliation(s)
- Ross Corriden
- Departments of Pharmacology and Medicine, University of California, San Diego, La Jolla, CA 92093, USA
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