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Balczon R, Lin MT, Voth S, Nelson AR, Schupp JC, Wagener BM, Pittet JF, Stevens T. Lung endothelium, tau, and amyloids in health and disease. Physiol Rev 2024; 104:533-587. [PMID: 37561137 PMCID: PMC11281824 DOI: 10.1152/physrev.00006.2023] [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: 02/02/2023] [Revised: 06/26/2023] [Accepted: 08/04/2023] [Indexed: 08/11/2023] Open
Abstract
Lung endothelia in the arteries, capillaries, and veins are heterogeneous in structure and function. Lung capillaries in particular represent a unique vascular niche, with a thin yet highly restrictive alveolar-capillary barrier that optimizes gas exchange. Capillary endothelium surveys the blood while simultaneously interpreting cues initiated within the alveolus and communicated via immediately adjacent type I and type II epithelial cells, fibroblasts, and pericytes. This cell-cell communication is necessary to coordinate the immune response to lower respiratory tract infection. Recent discoveries identify an important role for the microtubule-associated protein tau that is expressed in lung capillary endothelia in the host-pathogen interaction. This endothelial tau stabilizes microtubules necessary for barrier integrity, yet infection drives production of cytotoxic tau variants that are released into the airways and circulation, where they contribute to end-organ dysfunction. Similarly, beta-amyloid is produced during infection. Beta-amyloid has antimicrobial activity, but during infection it can acquire cytotoxic activity that is deleterious to the host. The production and function of these cytotoxic tau and amyloid variants are the subject of this review. Lung-derived cytotoxic tau and amyloid variants are a recently discovered mechanism of end-organ dysfunction, including neurocognitive dysfunction, during and in the aftermath of infection.
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Affiliation(s)
- Ron Balczon
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Mike T Lin
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Sarah Voth
- Department of Cell Biology and Physiology, Edward Via College of Osteopathic Medicine, Monroe, Louisiana, United States
| | - Amy R Nelson
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
| | - Jonas C Schupp
- Pulmonary and Critical Care Medicine, Department of Internal Medicine, Yale University, New Haven, Connecticut, United States
- Department of Respiratory Medicine, Hannover Medical School, Hannover, Germany
- German Center for Lung Research (DZL), Hannover, Germany
| | - Brant M Wagener
- Department of Anesthesiology and Perioperative Medicine, University of Alabama-Birmingham, Birmingham, Alabama, United States
| | - Jean-Francois Pittet
- Department of Anesthesiology and Perioperative Medicine, University of Alabama-Birmingham, Birmingham, Alabama, United States
| | - Troy Stevens
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, Alabama, United States
- Department of Internal Medicine, University of South Alabama, Mobile, Alabama, United States
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States
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Ng LG, Liu Z, Kwok I, Ginhoux F. Origin and Heterogeneity of Tissue Myeloid Cells: A Focus on GMP-Derived Monocytes and Neutrophils. Annu Rev Immunol 2023; 41:375-404. [PMID: 37126421 DOI: 10.1146/annurev-immunol-081022-113627] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Myeloid cells are a significant proportion of leukocytes within tissues, comprising granulocytes, monocytes, dendritic cells, and macrophages. With the identification of various myeloid cells that perform separate but complementary functions during homeostasis and disease, our understanding of tissue myeloid cells has evolved significantly. Exciting findings from transcriptomics profiling and fate-mapping mouse models have facilitated the identification of their developmental origins, maturation, and tissue-specific specializations. This review highlights the current understanding of tissue myeloid cells and the contributing factors of functional heterogeneity to better comprehend the complex and dynamic immune interactions within the healthy or inflamed tissue. Specifically, we discuss the new understanding of the contributions of granulocyte-monocyte progenitor-derived phagocytes to tissue myeloid cell heterogeneity as well as the impact of niche-specific factors on monocyte and neutrophil phenotype and function. Lastly, we explore the developing paradigm of myeloid cell heterogeneity during inflammation and disease.
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Affiliation(s)
- Lai Guan Ng
- Shanghai Immune Therapy Institute, Renji Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China;
- Singapore Immunology Network (SIgN), A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore; ,
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Zhaoyuan Liu
- Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Immanuel Kwok
- Singapore Immunology Network (SIgN), ASTAR (Agency for Science, Technology and Research), Biopolis, Singapore; ,
| | - Florent Ginhoux
- Singapore Immunology Network (SIgN), ASTAR (Agency for Science, Technology and Research), Biopolis, Singapore; ,
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Shanghai Institute of Immunology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Institut Gustave Roussy, INSERM U1015, Villejuif, France
- Translational Immunology Institute, SingHealth Duke-NUS Academic Medical Centre, Singapore
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3
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Calabrese F, Pezzuto F, Fortarezza F, Lunardi F, Faccioli E, Lorenzoni G, Boscolo A, Sella N, Gregori D, Schiavon M, Navalesi P, Dell’Amore A, Rea F. Evaluation of Tissue Ischemia/Reperfusion Injury in Lung Recipients Supported by Intraoperative Extracorporeal Membrane Oxygenation: A Single-Center Pilot Study. Cells 2022; 11:cells11223681. [PMID: 36429108 PMCID: PMC9688824 DOI: 10.3390/cells11223681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2022] [Revised: 11/10/2022] [Accepted: 11/17/2022] [Indexed: 11/22/2022] Open
Abstract
Intraoperative veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) as intraoperative hemodynamic support during lung transplantation is becoming a standard practice due to promising clinical results. Nevertheless, studies on tissue/molecular pathways investigating ischemia/reperfusion injury are still lacking. Patients receiving a bilateral lung transplantation between January 2012 and December 2018 at the University Hospital of Padova were included in this retrospective single-center observational study. The present study aimed to investigate ischemia/reperfusion injury in 51 tissue specimens obtained from 13 recipients supported by intraoperative VA-ECMO and 38 who were not. Several tissue analyses, including apoptosis evaluation and inducible nitric oxide synthase expression, were performed on the biopsies at the time of transplantation. Lung samples from the ECMO group (both pre- and post-reperfusion) were comparable, or for some parameters better, than samples from the non-ECMO group. Leukocyte margination was significantly lower in the ECMO group than in the non-ECMO group. Primary graft dysfunction, mainly at 24 and 48 h, was correlated with the tissue injury score of the post-reperfusion biopsy. The interquartile ranges for all morphological parameters showed high grade variability between pre- and post-reperfusion in the non-ECMO group. These preliminary data support the use of intraoperative ECMO based on lower lung tissue ischemia/reperfusion injury. Larger case series are mandatory to confirm our findings.
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Affiliation(s)
- Fiorella Calabrese
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
- Correspondence: ; Tel.: +39-0498272268
| | - Federica Pezzuto
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Francesco Fortarezza
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Francesca Lunardi
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Eleonora Faccioli
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Giulia Lorenzoni
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Annalisa Boscolo
- Institute of Anesthesia and Intensive Care, Padova University Hospital, 35128 Padova, Italy
- Department of Medicine, University of Padova, 35128 Padova, Italy
| | - Nicolò Sella
- Institute of Anesthesia and Intensive Care, Padova University Hospital, 35128 Padova, Italy
| | - Dario Gregori
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Marco Schiavon
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Paolo Navalesi
- Institute of Anesthesia and Intensive Care, Padova University Hospital, 35128 Padova, Italy
- Department of Medicine, University of Padova, 35128 Padova, Italy
| | - Andrea Dell’Amore
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
| | - Federico Rea
- Department of Cardiac, Thoracic, Vascular Sciences, and Public Health, University of Padova, 35128 Padova, Italy
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Chignalia AZ, Isbatan A, Patel M, Ripper R, Sharlin J, Shosfy J, Borlaug BA, Dull RO. Pressure-dependent NOS activation contributes to endothelial hyperpermeability in a model of acute heart failure. Biosci Rep 2018; 38:BSR20181239. [PMID: 30355657 PMCID: PMC6250809 DOI: 10.1042/bsr20181239] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 10/11/2018] [Accepted: 10/21/2018] [Indexed: 12/12/2022] Open
Abstract
Aims: Acute increases in left ventricular end diastolic pressure (LVEDP) can induce pulmonary edema (PE). The mechanism(s) for this rapid onset edema may involve more than just increased fluid filtration. Lung endothelial cell permeability is regulated by pressure-dependent activation of nitric oxide synthase (NOS). Herein, we demonstrate that pressure-dependent NOS activation contributes to vascular failure and PE in a model of acute heart failure (AHF) caused by hypertension.Methods and results: Male Sprague-Dawley rats were anesthetized and mechanically ventilated. Acute hypertension was induced by norepinephrine (NE) infusion and resulted in an increase in LVEDP and pulmonary artery pressure (Ppa) that were associated with a rapid fall in PaO2, and increases in lung wet/dry ratio and injury scores. Heart failure (HF) lungs showed increased nitrotyrosine content and ROS levels. L-NAME pretreatment mitigated the development of PE and reduced lung ROS concentrations to sham levels. Apocynin (Apo) pretreatment inhibited PE. Addition of tetrahydrobiopterin (BH4) to AHF rats lung lysates and pretreatment of AHF rats with folic acid (FA) prevented ROS production indicating endothelial NOS (eNOS) uncoupling.Conclusion: Pressure-dependent NOS activation leads to acute endothelial hyperpermeability and rapid PE by an increase in NO and ROS in a model of AHF. Acute increases in pulmonary vascular pressure, without NOS activation, was insufficient to cause significant PE. These results suggest a clinically relevant role of endothelial mechanotransduction in the pathogenesis of AHF and further highlights the concept of active barrier failure in AHF. Therapies targetting the prevention or reversal of endothelial hyperpermeability may be a novel therapeutic strategy in AHF.
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Affiliation(s)
- Andreia Z Chignalia
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL 60612, U.S.A.
| | - Ayman Isbatan
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL 60612, U.S.A
| | - Milan Patel
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL 60612, U.S.A
| | - Richard Ripper
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL 60612, U.S.A
- Research and Development Service, Jesse Brown Veterans Affairs Medical Center, 820 S Damen Ave., Chicago, IL 60612, U.S.A
| | - Jordan Sharlin
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL 60612, U.S.A
| | - Joelle Shosfy
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL 60612, U.S.A
| | - Barry A Borlaug
- Department of Cardiovascular Medicine, Mayo Clinic and Foundation, 200 First St SW, Rochester, MN 55905, U.S.A
| | - Randal O Dull
- Department of Anesthesiology, University of Illinois at Chicago, Chicago, IL 60612, U.S.A
- Department of Anesthesiology, University of Arizona College of Medicine and Banner-University Medical Center, Tucson, AZ 85724, U.S.A
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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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Middleton EA, Rondina MT, Schwertz H, Zimmerman GA. Amicus or Adversary Revisited: Platelets in Acute Lung Injury and Acute Respiratory Distress Syndrome. Am J Respir Cell Mol Biol 2018; 59:18-35. [PMID: 29553813 PMCID: PMC6039872 DOI: 10.1165/rcmb.2017-0420tr] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2017] [Accepted: 02/20/2018] [Indexed: 12/21/2022] Open
Abstract
Platelets are essential cellular effectors of hemostasis and contribute to disease as circulating effectors of pathologic thrombosis. These are their most widely known biologic activities. Nevertheless, recent observations demonstrate that platelets have a much more intricate repertoire beyond these traditional functions and that they are specialized for contributions to vascular barrier integrity, organ repair, antimicrobial host defense, inflammation, and activities across the immune continuum. Paradoxically, on the basis of clinical investigations and animal models of disease, some of these newly discovered activities of platelets appear to contribute to tissue injury. Studies in the last decade indicate unique interactions of platelets and their precursor, the megakaryocyte, in the lung and implicate platelets as essential effectors in experimental acute lung injury and clinical acute respiratory distress syndrome. Additional discoveries derived from evolving work will be required to precisely define the contributions of platelets to complex subphenotypes of acute lung injury and to determine if these remarkable and versatile blood cells are therapeutic targets in acute respiratory distress syndrome.
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Affiliation(s)
- Elizabeth A. Middleton
- Division of Pulmonary and Critical Care Medicine, and
- Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Matthew T. Rondina
- Division of General Internal Medicine, Department of Internal Medicine
- Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Hansjorg Schwertz
- Division of Vascular Surgery, Department of Surgery, and
- Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, Utah
| | - Guy A. Zimmerman
- Division of Pulmonary and Critical Care Medicine, and
- Program in Molecular Medicine, University of Utah School of Medicine, Salt Lake City, Utah
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7
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Pinar IP, Jones HD. Novel imaging approaches for small animal models of lung disease (2017 Grover Conference series). Pulm Circ 2018; 8:2045894018762242. [PMID: 29480066 PMCID: PMC5888832 DOI: 10.1177/2045894018762242] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Imaging in small animal models of lung disease is challenging, as existing technologies are limited either by resolution or by the terminal nature of the imaging approach. Here, we describe the current state of small animal lung imaging, the technological advances of laboratory-sourced phase contrast X-ray imaging, and the application of this novel technology and its attendant image analysis techniques to the in vivo imaging of the large airways and pulmonary vasculature in murine models of lung health and disease.
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Affiliation(s)
- Isaac P Pinar
- 1 Department of Mechanical and Aerospace Engineering, Monash University, Melbourne, VIC, Australia.,2 Division of Biological Engineering, Faculty of Engineering, Monash University, Melbourne, VIC, Australia
| | - Heather D Jones
- 3 Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, USA
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Abstract
In the United States trauma is the leading cause of mortality among those under the age of 45, claiming approximately 192,000 lives each year. Significant personal disability, lost productivity, and long-term healthcare needs are common and contribute 580 billion dollars in economic impact each year. Improving resuscitation strategies and the early acute care of trauma patients has the potential to reduce the pathological sequelae of combined exuberant inflammation and immune suppression that can co-exist, or occur temporally, and adversely affect outcomes. The endothelial and epithelial glycocalyx has emerged as an important participant in both inflammation and immunomodulation. Constituents of the glycocalyx have been used as biomarkers of injury severity and have the potential to be target(s) for therapeutic interventions aimed at immune modulation. In this review, we provide a contemporary understanding of the physiologic structure and function of the glycocalyx and its role in traumatic injury with a particular emphasis on lung injury.
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Burgstaller G, Vierkotten S, Lindner M, Königshoff M, Eickelberg O. Multidimensional immunolabeling and 4D time-lapse imaging of vital ex vivo lung tissue. Am J Physiol Lung Cell Mol Physiol 2015; 309:L323-32. [PMID: 26092995 DOI: 10.1152/ajplung.00061.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 06/10/2015] [Indexed: 11/22/2022] Open
Abstract
During the last decades, the study of cell behavior was largely accomplished in uncoated or extracellular matrix (ECM)-coated plastic dishes. To date, considerable cell biological efforts have tried to model in vitro the natural microenvironment found in vivo. For the lung, explants cultured ex vivo as lung tissue cultures (LTCs) provide a three-dimensional (3D) tissue model containing all cells in their natural microenvironment. Techniques for assessing the dynamic live interaction between ECM and cellular tissue components, however, are still missing. Here, we describe specific multidimensional immunolabeling of living 3D-LTCs, derived from healthy and fibrotic mouse lungs, as well as patient-derived 3D-LTCs, and concomitant real-time four-dimensional multichannel imaging thereof. This approach allowed the evaluation of dynamic interactions between mesenchymal cells and macrophages with their ECM. Furthermore, fibroblasts transiently expressing focal adhesions markers incorporated into the 3D-LTCs, paving new ways for studying the dynamic interaction between cellular adhesions and their natural-derived ECM. A novel protein transfer technology (FuseIt/Ibidi) shuttled fluorescently labeled α-smooth muscle actin antibodies into the native cells of living 3D-LTCs, enabling live monitoring of α-smooth muscle actin-positive stress fibers in native tissue myofibroblasts residing in fibrotic lesions of 3D-LTCs. Finally, this technique can be applied to healthy and diseased human lung tissue, as well as to adherent cells in conventional two-dimensional cell culture. This novel method will provide valuable new insights into the dynamics of ECM (patho)biology, studying in detail the interaction between ECM and cellular tissue components in their natural microenvironment.
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Affiliation(s)
- Gerald Burgstaller
- Comprehensive Pneumology Center, University Hospital of the Ludwig-Maximilians-University Munich and Helmholtz Zentrum München, Member of the German Center for Lung Research, Munich, Germany; and
| | - Sarah Vierkotten
- Comprehensive Pneumology Center, University Hospital of the Ludwig-Maximilians-University Munich and Helmholtz Zentrum München, Member of the German Center for Lung Research, Munich, Germany; and
| | - Michael Lindner
- Center for Thoracic Surgery, Asklepios Biobank for Lung Diseases, Comprehensive Pneumology Center, Asklepios Clinic Munich-Gauting, Germany
| | - Melanie Königshoff
- Comprehensive Pneumology Center, University Hospital of the Ludwig-Maximilians-University Munich and Helmholtz Zentrum München, Member of the German Center for Lung Research, Munich, Germany; and
| | - Oliver Eickelberg
- Comprehensive Pneumology Center, University Hospital of the Ludwig-Maximilians-University Munich and Helmholtz Zentrum München, Member of the German Center for Lung Research, Munich, Germany; and
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10
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Chakraborty S, Tewari S, Sharma RK, Narula SC, Ghalaut PS, Ghalaut V. Impact of iron deficiency anemia on chronic periodontitis and superoxide dismutase activity: a cross-sectional study. J Periodontal Implant Sci 2014; 44:57-64. [PMID: 24778899 PMCID: PMC3999353 DOI: 10.5051/jpis.2014.44.2.57] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2013] [Accepted: 02/28/2014] [Indexed: 11/16/2022] Open
Abstract
PURPOSE Both chronic periodontitis (CP) and iron deficiency anemia (IDA) induce oxidative stress in the body and cause an imbalance between reactive oxygen species and antioxidants, such as superoxide dismutase (SOD). This study explored the SOD enzyme activity of saliva and serum in CP patients with and without IDA and analyzed the impact of IDA on CP. METHODS A total of 82 patients were divided into four groups: control group (CG, 22), periodontally healthy IDA patients (IDA-PH, 20), CP patients (CP, 20), and IDA patients with CP (IDA-CP, 20). After clinical measurements and samplings, serum and salivary SOD levels were determined using an SOD assay kit. RESULTS IDA-CP patients exhibited a higher gingival index, bleeding on probing, probing pocket depth, and percentage (%) of sites with a clinical attachment loss (CAL) of ≥6 mm (P<0.008) than CP patients. The mean salivary and serum SOD levels were significantly lower in the IDA-PH, CP, and IDA-CP patients than in the CG group (P<0.008). A significant positive correlation between salivary and serum SOD activity was observed in IDA (P<0.05). Furthermore, serum and salivary SOD levels were significantly and negatively correlated with all periodontal parameters including the percentage of sites with CAL of 4-5 and ≥6 mm (P<0.05) except the significant correlation between salivary SOD activity and mean CAL and the percentage of sites with CAL of 4-5 mm (P>0.05) in these patients. CONCLUSIONS Within the limits of this study, it may be suggested that IDA patients with chronic periodontitis have more periodontal breakdowns than patients with chronic periodontitis. Serum and salivary SOD activity levels were lower in the IDA-PH, CP and IDA-CP groups than in the CG. Iron deficiency anemia influenced the serum SOD activity but did not seem to affect the salivary SOD activity in these patients.
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Affiliation(s)
- Souvik Chakraborty
- Department of Periodontics and Oral Implantology, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
| | - Shikha Tewari
- Department of Periodontics and Oral Implantology, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
| | - Rajinder Kumar Sharma
- Department of Periodontics and Oral Implantology, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
| | - Satish Chander Narula
- Department of Periodontics and Oral Implantology, Post Graduate Institute of Dental Sciences, Rohtak, Haryana, India
| | - Pratap Singh Ghalaut
- Department of Medicine, Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
| | - Veena Ghalaut
- Department of Biochemistry, Post Graduate Institute of Medical Sciences, Rohtak, Haryana, India
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11
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Bou Saab J, Losa D, Chanson M, Ruez R. Connexins in respiratory and gastrointestinal mucosal immunity. FEBS Lett 2014; 588:1288-96. [PMID: 24631537 DOI: 10.1016/j.febslet.2014.02.059] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 02/27/2014] [Accepted: 02/27/2014] [Indexed: 12/18/2022]
Abstract
The mucosal lining forms the physical and chemical barrier that protects against pathogens and hostile particles and harbors its own population of bacteria, fungi and archea, known as the microbiota. The immune system controls tolerance of this population of microorganisms that have proven to be beneficial for its host. Keeping its physical integrity and a correct balance with the microbiota, the mucosa preserves its homeostasis and its protective function and maintains host's health. However, in some conditions, pathogens may succeed in breaching mucosal homeostasis and successfully infecting the host. In this review we will discuss the role the mucosa plays in the defense against bacterial pathogens by considering the gap junction protein connexins. We will detail their implication in mucosal homeostasis and upon infection with bacteria in the respiratory and the gastrointestinal tracts.
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Affiliation(s)
- Joanna Bou Saab
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Davide Losa
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland
| | - Marc Chanson
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland.
| | - Richard Ruez
- Geneva University Hospitals and University of Geneva, Geneva, Switzerland
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12
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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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13
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Emin MT, Sun L, Huertas A, Das S, Bhattacharya J, Bhattacharya S. Platelets induce endothelial tissue factor expression in a mouse model of acid-induced lung injury. Am J Physiol Lung Cell Mol Physiol 2012; 302:L1209-20. [PMID: 22505671 DOI: 10.1152/ajplung.00189.2011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Although the lung expresses procoagulant proteins under inflammatory conditions, underlying mechanisms remain unclear. Here, we addressed lung endothelial expression of tissue factor (TF), which initiates the coagulation cascade and expression of which signifies development of a procoagulant phenotype in the vasculature. To establish the model of acid-induced acute lung injury (ALI), we intranasally instilled anesthetized mice with saline or acid. Then 2 h later, we isolated pulmonary vascular cells for flow cytometry and confocal microscopy to detect the leukocyte antigen, CD45 and the endothelial markers VE-cadherin and von Willebrand factor (vWf). Acid increased both the number of vWf-expressing cells as well as TF and P-selectin expressions on these cells. All of these effects were markedly inhibited by treating mice with antiplatelet serum, suggesting the involvement of platelets. The increased expressions of TF, vWf, and P-selectin in response to acid also occurred in platelets. Moreover, the effects were replicated in endothelial cells derived from isolated, blood-perfused lungs. However, the effect was inhibited completely in lungs perfused with platelet-depleted and, to a lesser extent, with leukocyte-depleted blood. Acid injury increased endothelial expressions of the platelet proteins, CD41 and CD42b, providing evidence that platelet proteins were transferred to the vascular surface. Reactive oxygen species (ROS) were implicated in these responses, in that the endothelial and platelet protein expressions were inhibited. We conclude that acid-induced ALI causes NOX2-mediated ROS generation that activates platelets, which then generate a procoagulant endothelial surface.
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Affiliation(s)
- Memet T Emin
- Department of Pediatrics, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA
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14
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Kandasamy K, Sahu G, Parthasarathi K. Real-time imaging reveals endothelium-mediated leukocyte retention in LPS-treated lung microvessels. Microvasc Res 2012; 83:323-31. [PMID: 22342350 DOI: 10.1016/j.mvr.2012.01.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2011] [Revised: 12/31/2011] [Accepted: 01/31/2012] [Indexed: 01/01/2023]
Abstract
Endotoxemia, a major feature of sepsis, is a common cause of acute lung injury and initiates rapid accumulation of leukocytes in the lung vasculature. Endothelial mechanisms that underlie this accumulation remain unclear, as current experimental models of endotoxemia are less suitable for targeted activation of the endothelium. Toward elucidating this, we used the isolated blood-perfused rat lung preparation. With a microcatheter inserted through a left atrial cannula, we cleared blood cells from a small lung region and then infused lipopolysaccharide (LPS) into microvessels. After a Ringer's wash to remove residual LPS, we infused fluorescently-labeled autologous leukocytes and imaged their transit through the treated microvessels. Image analysis revealed that leukocytes infused 90 min after LPS treatment were retained more in treated venules and capillaries than untreated vessels. Further, pretreatment with either the intercellular adhesion molecule-1 (ICAM-1) mAb or polymyxin-B blunted LPS-induced leukocyte retention in both microvessel segments. In addition, retention of leukocytes treated ex vivo with LPS in LPS-treated microvessels was higher compared to retention of untreated leukocytes. In situ immunofluorescence experiments revealed that LPS significantly increased microvessel ICAM-1 expression at 90 min post treatment. Polymyxin pretreatment inhibited this increase. Taken together, the data suggest that LPS increased leukocyte retention in both venules and capillaries and this response was mediated by the increased expression of endothelial ICAM-1. Thus, endothelial mechanisms may themselves play a major role in LPS-induced leukocyte retention in lung microvessels. Blunting the endothelial responses may mitigate endotoxin-induced morbidity.
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Affiliation(s)
- Kathirvel Kandasamy
- Department of Physiology, The University of Tennessee Health Science Center, Memphis, TN 38163, USA
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15
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Parthasarathi K, Bhattacharya J. Localized acid instillation by a wedged-catheter method reveals a role for vascular gap junctions in spatial expansion of acid injury. Anat Rec (Hoboken) 2011; 294:1585-91. [PMID: 21809471 DOI: 10.1002/ar.21460] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2010] [Revised: 05/31/2011] [Accepted: 06/22/2011] [Indexed: 01/23/2023]
Abstract
Acid aspiration is a major cause of acute lung injury. However, the mechanisms that underlie this spatial expansion of the injury remain undefined. In current animal models of acid injury, intratracheal acid instillation replicates the lung injury. However intratracheal instillation causes a global effect, precluding studies of how the injury spreads. Here, we report an airway catheter-based method for localized acid delivery in the isolated blood-perfused rat lung. We co-instilled hydrochloric acid with evans blue through the catheter into one lung and determined blood-free extravascular lung water in tissue samples from regions that either received, or did not receive the instilled acid. Tissue samples from the noncatheterized contralateral lung were used as controls. Lung water increased both in the regions that received acid, as well as in adjacent regions that did not. Pretreating the lung with vascular infusions of the gap junctional blocker, glycerrhetinic acid, blunted the acid-induced lung water increase at the adjacent regions. These findings indicate that endothelial gap junction communication causes spread of lung injury from regions that were directly acid injured, to adjacent sites that did not directly receive acid. Our new method for establishing localized acid injury provides evidence for a novel role for vascular gap junctions in the spatial expansion of acid injury.
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Affiliation(s)
- Kaushik Parthasarathi
- Departments of Physiology and Biomedical Engineering, University of Tennessee Health Science Center, Memphis, TN 38163, USA
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16
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Sarieddine MZR, Scheckenbach KEL, Foglia B, Maass K, Garcia I, Kwak BR, Chanson M. Connexin43 modulates neutrophil recruitment to the lung. J Cell Mol Med 2009; 13:4560-70. [PMID: 19166484 PMCID: PMC4515071 DOI: 10.1111/j.1582-4934.2008.00654.x] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Transmigration of neutrophils through the microvascular endothelium is a cardinal event of acute inflammation. It has been suggested that gap junctions made of connexin43 (Cx43) may serve as a conducting pathway to spread inflammatory signals within the lung capillary network. To determine whether Cx43 contributes to neutrophil transmigration in vivo, the number of transmigrated neutrophils was monitored in lungs of Cx43 mouse models subjected to inflammation by intratracheal instillations of Pseudomonas aeruginosa lipopolysaccharide (LPS). Cx43 was detected in inflamed lungs independently of neutrophil recruitment, whereas Cx43 up-regulation was not detected in mice genetically protected from inflammation. Mice heterozygous for the Cx43 gene (gja1) showed a 56% (P < 0.01) reduction in airway neutrophil count. In contrast, increased (P < 0.05) neutrophil recruitment in response to LPS was observed in a mouse model expressing a mutant Cx43 with enhanced channel conductivity. In vitro adhesion assays showed that reduced conductivity of Cx43 channels with (43)Gap26, a Cx43 blocking peptide, decreased adhesion of neutrophils to endothelial cells. Finally, we found that instillation of (43)Gap26 in inflamed lungs reduced neutrophil transmigration by 65% (P < 0.05). These results indicate that inflammatory mediators up-regulate alveolar Cx43 to promote neutrophil recruitment to the airspace. Cx43 may therefore represent a pharmacological target in lung diseases characterized by excessive neutrophil recruitment to the airways.
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Affiliation(s)
- Maya Z Richani Sarieddine
- Laboratory of Clinical Investigation III, Department of Pediatrics, Geneva University Hospitals and University of Geneva, Geneva, Switzerland
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17
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Maniatis NA, Kotanidou A, Catravas JD, Orfanos SE. Endothelial pathomechanisms in acute lung injury. Vascul Pharmacol 2008; 49:119-33. [PMID: 18722553 PMCID: PMC7110599 DOI: 10.1016/j.vph.2008.06.009] [Citation(s) in RCA: 155] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2008] [Accepted: 06/09/2008] [Indexed: 12/14/2022]
Abstract
Acute lung injury (ALI) and its most severe extreme the acute respiratory distress syndrome (ARDS) refer to increased-permeability pulmonary edema caused by a variety of pulmonary or systemic insults. ALI and in particular ARDS, are usually accompanied by refractory hypoxemia and the need for mechanical ventilation. In most cases, an exaggerated inflammatory and pro-thrombotic reaction to an initial stimulus, such as systemic infection, elicits disruption of the alveolo-capillary membrane and vascular fluid leak. The pulmonary endothelium is a major metabolic organ promoting adequate pulmonary and systemic vascular homeostasis, and a main target of circulating cells and humoral mediators under injury; pulmonary endothelium is therefore critically involved in the pathogenesis of ALI. In this review we will discuss mechanisms of pulmonary endothelial dysfunction and edema generation in the lung with special emphasis on the interplay between the endothelium, the immune and hemostatic systems, and highlight how these principles apply in the context of defined disorders and specific insults implicated in ALI pathogenesis.
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Affiliation(s)
| | - Anastasia Kotanidou
- “M. Simou” Laboratory, University of Athens Medical School, Athens, Greece
- 1st Department of Critical Care, Evangelismos Hospital, University of Athens Medical School, Athens, Greece
| | - John D. Catravas
- Vascular Biology Center, Medical College of Georgia, Augusta, GA, United States
| | - Stylianos E. Orfanos
- “M. Simou” Laboratory, University of Athens Medical School, Athens, Greece
- 2nd Department of Critical Care, Attikon Hospital, University of Athens Medical School, Athens, Greece
- Corresponding author. 2nd Department of Critical Care, Attikon Hospital, 1, Rimini St., 124 62, Haidari, Athens, Greece. Tel.: +30 210 7235521; fax: +30 210 7239127.
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18
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Parker JC, Townsley MI. Physiological determinants of the pulmonary filtration coefficient. Am J Physiol Lung Cell Mol Physiol 2008; 295:L235-7. [PMID: 18502816 DOI: 10.1152/ajplung.00064.2008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Current emphasis on translational application of genetic models of lung disease has renewed interest in the measurement of the gravimetric filtration coefficient (K(f)) as a means to assess vascular permeability changes in isolated perfused lungs. The K(f) is the product of the hydraulic conductivity and the filtration surface area, and is a sensitive measure of vascular fluid permeability when the pulmonary vessels are fully recruited and perfused. We have observed a remarkable consistency of the normalized baseline K(f) values between species with widely varying body weights from mice to sheep. Uniformity of K(f) values can be attributed to the thin alveolar capillary barrier required for gas exchange and the conserved matching of lung vascular surface area to the oxygen requirements of the body mass. An allometric correlation between the total lung filtration coefficient (K(f,t)) and body weight in several species (r(2)=1.00) had a slope that was similar to those reported for alveolar and pulmonary capillary surface areas and pulmonary diffusion coefficients determined by morphometric methods in these species. A consistent K(f) is dependent on accurately separating the filtration and vascular volume components of lung weight gain, then K(f) is a consistent and repeatable index of lung vascular permeability.
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Affiliation(s)
- James C Parker
- Department of Physiology and Center for Lung Biology, College of Medicine, University of South Alabama, Mobile, Alabama 36688, USA.
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19
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Kiefmann R, Rifkind JM, Nagababu E, Bhattacharya J. Red blood cells induce hypoxic lung inflammation. Blood 2008; 111:5205-14. [PMID: 18270324 PMCID: PMC2384143 DOI: 10.1182/blood-2007-09-113902] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Accepted: 01/30/2008] [Indexed: 01/03/2023] Open
Abstract
Hypoxia, which commonly associates with respiratory and cardiovascular diseases, provokes an acute inflammatory response. However, underlying mechanisms are not well understood. Here we report that red blood cells (RBCs) induce hypoxic inflammation by producing reactive oxygen species (ROS) that diffuse to endothelial cells of adjoining blood vessels. Real-time fluorescence imaging of rat and mouse lungs revealed that in the presence of RBC-containing vascular perfusion, hypoxia increased microvascular ROS, and cytosolic Ca(2+), leading to P-selectin-dependent leukocyte recruitment. However, in the presence of RBC-free perfusion, all hypoxia-induced responses were completely inhibited. Because hemoglobin (Hb) autoxidation causes RBC superoxide formation that readily dismutates to H(2)O(2), hypoxia-induced responses were lost when we inhibited Hb autoxidation with CO or nitrite, or when the H(2)O(2) inhibitor, catalase was added to the infusion to neutralize the RBC-derived ROS. By contrast, perfusion with RBCs from BERK-trait mice that are more susceptible to Hb autoxidation and to hypoxia-induced superoxide production enhanced the hypoxia-induced responses. We conclude that in hypoxia, increased Hb autoxidation augments superoxide production in RBCs. Consequently, RBCs release H(2)O(2) that diffuses to the lung microvascular endothelium, thereby initiating Ca(2+)-dependent leukocyte recruitment. These findings are the first evidence that RBCs contribute to hypoxia-induced inflammation.
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Affiliation(s)
- Rainer Kiefmann
- Lung Biology Laboratory, College of Physicians & Surgeons, Columbia University, St Luke's Roosevelt Hospital Center, New York, NY, USA
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20
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Bertuglia S, Ichimura H, Fossati G, Parthasarathi K, Leoni F, Modena D, Cremonesi P, Bhattacharya J, Mascagni P. ITF1697, a stable Lys-Pro-containing peptide, inhibits weibel-palade body exocytosis induced by ischemia/reperfusion and pressure elevation. Mol Med 2008; 13:615-24. [PMID: 17948065 DOI: 10.2119/2007-00079.bertuglia] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Accepted: 10/09/2007] [Indexed: 11/06/2022] Open
Abstract
A number of Lys-Pro-containing short peptides have been described as possessing a variety of biological activities in vitro. Because of limited metabolic stability, however, their efficacy in vivo is uncertain. To exploit the pharmacological potential of Lys-Pro-containing short peptides, we synthesized a series of chemically modified forms of these peptides. One of them, ITF1697 (Gly-(Nalpha-Et)Lys-Pro-Arg) was stable in vivo and particularly efficacious in experimental models of disseminated endotoxemia and of cardiovascular disorders. Using intravital fluorescence microscopy, we studied the peptide cellular and molecular basis of protection in the Syrian hamster cheek pouch microcirculation subjected to ischemia/reperfusion (I/R) and in pressure elevation-induced proinflammatory responses in isolated Sprague-Dawley rat lungs. Continuous intravenous infusion of ITF1697 at 0.1 to 100 mug/kg/min nearly completely protected the cheek pouch microcirculation from I/R injury as measured by decreased vascular permeability and increased capillary perfusion. Adhesion of leukocytes and platelets to blood vessels was strongly inhibited by the peptide. ITF1697 exerted its activity at the early stages of endothelial activation and inhibited P-selectin and von Willebrand factor secretion. Further mechanistic studies in the rat lung preparation revealed that the peptide inhibited the intracellular Ca(2+)-dependent fusion of Weibel-Palade bodies with the plasma membrane. The ability of ITF1697 to inhibit the early functions of activated endothelial cells, such as the exocytosis of Weibel-Palade bodies, represents a novel and promising pharmacological tool in model of pathologies of a variety of microvascular disorders.
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Affiliation(s)
- Silvia Bertuglia
- CNR Institute of Clinical Physiology, Medical School, University of Pisa, Pisa, Italy
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21
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Bhattacharya J. Interpreting the lung microvascular filtration coefficient. Am J Physiol Lung Cell Mol Physiol 2007; 293:L9-L10. [PMID: 17468133 DOI: 10.1152/ajplung.00148.2007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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22
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Dull RO, Mecham I, McJames S. Heparan sulfates mediate pressure-induced increase in lung endothelial hydraulic conductivity via nitric oxide/reactive oxygen species. Am J Physiol Lung Cell Mol Physiol 2007; 292:L1452-8. [PMID: 17351062 DOI: 10.1152/ajplung.00376.2006] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated the nonlinear dynamics of the pressure vs. hydraulic conductivity (Lp) relationship in lung microvascular endothelial cells and demonstrate that heparan sulfates, an important component of the endothelial glycocalyx, participate in pressure-sensitive mechanotransduction that results in barrier dysfunction. The pressure vs. Lp relationship was complex, possessing both time- and pressure-dependent components. Pretreatment of lung capillary endothelial cells with heparanase III completely abolished the pressure-induced increase in Lp. This extends our ( 7 ) previous observation regarding heparan sulfates as mechanotransducers for shear stress. Inhibition of nitric oxide (NO) synthase with l-NAME ( NG-nitro-l-arginine methyl ester HCl) and intracellular scavenging of reactive oxygen species (ROS) by TBAP [tetrakis-(4-benzoic acid) porphorin] significantly attenuated the pressure-induced Lp response. Intracellular NO/ROS were visualized using the fluorescent dye, 2′7′-dichlorofluorescein diacetate (DCFA), and cells demonstrated a pressure-induced increase in intracellular fluorescence. Heparanase pretreatment significantly reduced the pressure-induced increase in intracellular fluorescence, suggesting that cell-surface heparan sulfates directly participate in mechanotransduction that results in NO/ROS production and increased permeability. This is the first report to demonstrate a role for heparan sulfates in pressure-mediated mechanotransduction and barrier regulation. These observations may have important clinical implications during conditions where pulmonary microvascular pressure is elevated.
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Affiliation(s)
- Randal O Dull
- Univ. of Utah School of Medicine, Dept. of Anesthesiology, Lung Vascular Biology Laboratory, 30 North 1900 East, 3C444 SOM, Salt Lake City, UT 84132, USA.
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23
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Abstract
Although proinflammatory cell signaling in the alveolo-capillary region predisposes to acute lung injury, key cell-signaling mechanisms remain inadequately understood. Alveolo-capillary inflammation is likely to involve coordinated signaling among cells of different phenotypes. For example, migration of inflammatory cells into the alveolus might entail coordinated signaling between adjoining alveolar epithelial and microvascular endothelial cells. The popular cultured cell experimental strategy fails to replicate this multicellular environment. Cultured lung cells, both alveolar and endothelial, undergo phenotypic transformations; hence they might inadequately reflect innate responses of native cells. Consequently, new approaches are required for the investigation of cell signaling in the native setting. Here we summarize new developments in classical intravital microscopy and discuss real-time fluorescence imaging as a novel technique for studying second-messenger mechanisms in the alveolo-capillary region.
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Parthasarathi K, Ichimura H, Monma E, Lindert J, Quadri S, Issekutz A, Bhattacharya J. Connexin 43 mediates spread of Ca2+-dependent proinflammatory responses in lung capillaries. J Clin Invest 2006; 116:2193-200. [PMID: 16878174 PMCID: PMC1518791 DOI: 10.1172/jci26605] [Citation(s) in RCA: 127] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2005] [Accepted: 06/06/2006] [Indexed: 01/11/2023] Open
Abstract
Acute lung injury (ALI), which is associated with a mortality of 30-40%, is attributable to inflammation that develops rapidly across the lung's vast vascular surface, involving an entire lung or even both lungs. No specific mechanism explains this extensive inflammatory spread, probably because of the lack of approaches for detecting signal conduction in lung capillaries. Here, we addressed this question by applying the photolytic uncaging approach to induce focal increases in Ca2+ levels in targeted endothelial cells of alveolar capillaries. Uncaging caused Ca2+ levels to increase not only in the targeted cell, but also in vascular locations up to 150 microm from the target site, indicating that Ca2+ was conducted from the capillary to adjacent vessels. No such conduction was evident in mouse lungs lacking endothelial connexin 43 (Cx43), or in rat lungs in which we pretreated vessels with peptide inhibitors of Cx43. These findings provide the first direct evidence to our knowledge that interendothelial Ca2+ conduction occurs in the lung capillary bed and that Cx43-containing gap junctions mediate the conduction. A proinflammatory effect was evident in that induction of increases in Ca2+ levels in the capillary activated expression of the leukocyte adherence receptor P-selectin in venules. Further, peptide inhibitors of Cx43 completely blocked thrombin-induced microvascular permeability increases. Together, our findings reveal a novel role for Cx43-mediated gap junctions, namely as conduits for the spread of proinflammatory signals in the lung capillary bed. Gap junctional mechanisms require further consideration in the understanding of ALI.
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Affiliation(s)
- Kaushik Parthasarathi
- Lung Biology Laboratory, St. Luke's-Roosevelt Hospital Center, Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University, New York, New York 10019, USA.
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