1
|
Engelbrecht E, Kooistra T, Knipe RS. The Vasculature in Pulmonary Fibrosis. CURRENT TISSUE MICROENVIRONMENT REPORTS 2022; 3:83-97. [PMID: 36712832 PMCID: PMC9881604 DOI: 10.1007/s43152-022-00040-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 05/23/2022] [Indexed: 02/02/2023]
Abstract
Purpose of Review The current paradigm of idiopathic pulmonary fibrosis (IPF) pathogenesis involves recurrent injury to a sensitive alveolar epithelium followed by impaired repair responses marked by fibroblast activation and deposition of extracellular matrix. Multiple cell types are involved in this response with potential roles suggested by advances in single-cell RNA sequencing and lung developmental biology. Notably, recent work has better characterized the cell types present in the pulmonary endothelium and identified vascular changes in patients with IPF. Recent Findings Lung tissue from patients with IPF has been examined at single-cell resolution, revealing reductions in lung capillary cells and expansion of a population of vascular cells expressing markers associated with bronchial endothelium. In addition, pre-clinical models have demonstrated a fundamental role for aging and vascular permeability in the development of pulmonary fibrosis. Summary Mounting evidence suggests that the endothelium undergoes changes in the context of fibrosis, and these changes may contribute to the development and/or progression of pulmonary fibrosis. Additional studies will be needed to further define the functional role of these vascular changes.
Collapse
Affiliation(s)
| | - Tristan Kooistra
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| | - Rachel S. Knipe
- Division of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Harvard Medical School, Boston, MA
| |
Collapse
|
2
|
Extracellular vesicles in acute respiratory distress syndrome: Recent developments from bench to bedside. Int Immunopharmacol 2021; 100:108118. [PMID: 34492532 DOI: 10.1016/j.intimp.2021.108118] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Revised: 08/26/2021] [Accepted: 08/29/2021] [Indexed: 12/19/2022]
Abstract
Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), characterized by a large number of inflammatory cell aggregation and alveolar cell damage in pathophysiology, have extremely high morbidity and mortality in critically ill patients. In recent years, more and more studies have found that there are abundant extracellular vesicles (EVs) in animal models and patients with ALI/ARDS, and they play a critical role in the pathogenesis of lung injury. Clarifying the mechanisms of EVs in lung injury is of great significance in the diagnosis and treatment of ALI/ARDS. In this review, we will summarize the recent findings on the roles of EVs derived from different cells in ALI/ARDS, along with the formation, function, and related effects of EVs, and explore their potential clinical application for the diagnosis and treatment of ALI/ARDS.
Collapse
|
3
|
Bommakanti N, Isbatan A, Bavishi A, Dharmavaram G, Chignalia AZ, Dull RO. Hypercapnic acidosis attenuates pressure-dependent increase in whole-lung filtration coefficient (K f). Pulm Circ 2017; 7:719-726. [PMID: 28727979 PMCID: PMC5841912 DOI: 10.1177/2045893217724414] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Hypercapnic acidosis (HCA) has beneficial effects in experimental models of lung injury by attenuating inflammation and decreasing pulmonary edema. However, HCA increases pulmonary vascular pressure that will increase fluid filtration and worsen edema development. To reconcile these disparate effects, we tested the hypothesis that HCA inhibits endothelial mechanotransduction and protects against pressure-dependent increases in the whole lung filtration coefficient (Kf). Isolated perfused rat lung preparation was used to measure whole lung filtration coefficient (Kf) at two levels of left atrial pressure (PLA = 7.5 versus 15 cm H2O) and at low tidal volume (LVt) versus standard tidal volume (STVt) ventilation. The ratio of Kf2/Kf1 was used as the index of whole lung permeability. Double occlusion pressure, pulmonary artery pressure, pulmonary capillary pressures, and zonal characteristics (ZC) were measured to assess effects of HCA on hemodynamics and their relationship to Kf2/Kf1. An increase in PLA2 from 7.5 to 15 cm H2O resulted in a 4.9-fold increase in Kf2/Kf1 during LVt and a 4.8-fold increase during STVt. During LVt, HCA reduced Kf2/Kf1 by 2.7-fold and reduced STVt Kf2/Kf1 by 5.2-fold. Analysis of pulmonary hemodynamics revealed no significant differences in filtration forces in response to HCA. HCA interferes with lung vascular mechanotransduction and prevents pressure-dependent increases in whole lung filtration coefficient. These results contribute to a further understanding of the lung protective effects of HCA.
Collapse
Affiliation(s)
- Nikhil Bommakanti
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,2 Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Ayman Isbatan
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Avni Bavishi
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Gourisree Dharmavaram
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Andreia Z Chignalia
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| | - Randal O Dull
- 1 Department of Anesthesiology, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,2 Department of Bioengineering, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA.,3 Lung Vascular Biology Laboratory, University of Illinois at Chicago, College of Medicine, Chicago, IL, USA
| |
Collapse
|
4
|
Kuebler WM. The Flow-Dependent Transcription Factor KLF2 Protects Lung Vascular Barrier Function in Acute Respiratory Distress Syndrome. Am J Respir Crit Care Med 2017; 195:553-555. [DOI: 10.1164/rccm.201609-1946ed] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Affiliation(s)
- Wolfgang M. Kuebler
- Institute of PhysiologyCharité–Universitaetsmedizin BerlinBerlin, Germany
- The Keenan Research Centre for Biomedical Science at St. Michael’sToronto, Ontario, Canada
- Department of Surgeryand
- Department of PhysiologyUniversity of TorontoToronto, Ontario, Canada
| |
Collapse
|
5
|
Colbert JF, Schmidt EP. Endothelial and Microcirculatory Function and Dysfunction in Sepsis. Clin Chest Med 2016; 37:263-75. [PMID: 27229643 DOI: 10.1016/j.ccm.2016.01.009] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The microcirculation is a series of arterioles, capillaries, and venules that performs essential functions of oxygen and nutrient delivery, customized to the unique physiologic needs of the supplied organ. The homeostatic microcirculatory response to infection can become harmful if overactive and/or dysregulated. Pathologic microcirculatory dysfunction can be directly visualized by intravital microscopy or indirectly measured via detection of circulating biomarkers. Although several treatments have been shown to protect the microcirculation during sepsis, they have not improved patient outcomes when applied indiscriminately. Future outcomes-oriented studies are needed to test sepsis therapeutics when personalized to a patient's microcirculatory dysfunction.
Collapse
Affiliation(s)
- James F Colbert
- Division of Infectious Diseases, Department of Medicine, University of Colorado School of Medicine, 12700 E. 19th Avenue, Aurora, CO 80045, USA
| | - Eric P Schmidt
- Division of Pulmonary Sciences and Critical Care Medicine, Department of Medicine, Denver Health Medical Center, University of Colorado School of Medicine, 12700 E. 19th Avenue, Aurora, CO 80045, USA.
| |
Collapse
|
6
|
Goldenberg NM, Kuebler WM. Endothelial cell regulation of pulmonary vascular tone, inflammation, and coagulation. Compr Physiol 2016; 5:531-59. [PMID: 25880504 DOI: 10.1002/cphy.c140024] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The pulmonary endothelium represents a heterogeneous cell monolayer covering the luminal surface of the entire lung vasculature. As such, this cell layer lies at a critical interface between the blood, airways, and lung parenchyma, and must act as a selective barrier between these diverse compartments. Lung endothelial cells are able to produce and secrete mediators, display surface receptor, and cellular adhesion molecules, and metabolize circulating hormones to influence vasomotor tone, both local and systemic inflammation, and coagulation functions. In this review, we will explore the role of the pulmonary endothelium in each of these systems, highlighting key regulatory functions of the pulmonary endothelial cell, as well as novel aspects of the pulmonary endothelium in contrast to the systemic cell type. The interactions between pulmonary endothelial cells and both leukocytes and platelets will be discussed in detail, and wherever possible, elements of endothelial control over physiological and pathophysiological processes will be examined.
Collapse
Affiliation(s)
- Neil M Goldenberg
- The Keenan Research Centre for Biomedical Science of St. Michael's, Toronto, Ontario, Canada; Department of Anesthesia, University of Toronto, Ontario, Canada
| | - Wolfgang M Kuebler
- The Keenan Research Centre for Biomedical Science of St. Michael's, Toronto, Ontario, Canada; German Heart Institute Berlin, Germany; Institute of Physiology, Charité-Universitätsmedizin Berlin, Germany; Department of Surgery, University of Toronto, Ontario, Canada; Department of Physiology, University of Toronto, Ontario,Canada
| |
Collapse
|
7
|
Breitling S, Ravindran K, Goldenberg NM, Kuebler WM. The pathophysiology of pulmonary hypertension in left heart disease. Am J Physiol Lung Cell Mol Physiol 2015; 309:L924-41. [DOI: 10.1152/ajplung.00146.2015] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2015] [Accepted: 08/20/2015] [Indexed: 12/17/2022] Open
Abstract
Pulmonary hypertension (PH) is characterized by elevated pulmonary arterial pressure leading to right-sided heart failure and can arise from a wide range of etiologies. The most common cause of PH, termed Group 2 PH, is left-sided heart failure and is commonly known as pulmonary hypertension with left heart disease (PH-LHD). Importantly, while sharing many clinical features with pulmonary arterial hypertension (PAH), PH-LHD differs significantly at the cellular and physiological levels. These fundamental pathophysiological differences largely account for the poor response to PAH therapies experienced by PH-LHD patients. The relatively high prevalence of this disease, coupled with its unique features compared with PAH, signal the importance of an in-depth understanding of the mechanistic details of PH-LHD. The present review will focus on the current state of knowledge regarding the pathomechanisms of PH-LHD, highlighting work carried out both in human trials and in preclinical animal models. Adaptive processes at the alveolocapillary barrier and in the pulmonary circulation, including alterations in alveolar fluid transport, endothelial junctional integrity, and vasoactive mediator secretion will be discussed in detail, highlighting the aspects that impact the response to, and development of, novel therapeutics.
Collapse
Affiliation(s)
- Siegfried Breitling
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
- Institute for Chemistry and Biochemistry, Freie Universität Berlin, Germany
| | - Krishnan Ravindran
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
| | - Neil M. Goldenberg
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
- Department of Anesthesia, University of Toronto, Toronto, Ontario, Canada
| | - Wolfgang M. Kuebler
- Keenan Research Centre for Biomedical Science, St. Michael's Hospital, Toronto, Ontario, Canada
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Germany
- Departments of Surgery and Physiology, University of Toronto, Toronto, Ontario, Canada; and
- German Heart Institute Berlin, Berlin, Germany
| |
Collapse
|
8
|
Rentsendorj O, D'Alessio FR, Pearse DB. Phosphodiesterase 2A is a major negative regulator of iNOS expression in lipopolysaccharide-treated mouse alveolar macrophages. J Leukoc Biol 2014; 96:907-15. [PMID: 25063878 DOI: 10.1189/jlb.3a0314-152r] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
PDE2A is a dual-function PDE that is stimulated by cGMP to hydrolyze cAMP preferentially. In a two-hit model of ALI, we found previously that PDE2A decreased lung cAMP, up-regulated lung iNOS, and exacerbated ALI. Recent data suggest that macrophage iNOS expression contributes to ALI but later, promotes lung-injury resolution. However, macrophage iNOS is increased by cAMP, suggesting that PDE2A could negatively regulate macrophage iNOS expression. To test this, we examined the effects of manipulating PDE2A expression and function on LPS-induced iNOS expression in a mouse AM cell line (MH-S) and primary mouse AMs. In MH-S cells, LPS (100 ng/ml) increased PDE2A expression by 15% at 15 min and 50% at 6 h before decreasing at 24 h and 48 h. iNOS expression appeared at 6 h and remained increased 48 h post-LPS. Compared with control Ad, Ad.PDE2A-shRNA enhanced LPS-induced iNOS expression further by fourfold, an effect mimicked by the PDE2A inhibitor BAY 60-7550. Adenoviral PDE2A overexpression or treatment with ANP decreased LPS-induced iNOS expression. ANP-induced inhibition of iNOS was lost by knocking down PDE2A and was not mimicked by 8-pCPT-cGMP, a cGMP analog that does not stimulate PDE2A activity. Finally, we found that in primary AMs from LPS-treated mice, PDE2A knockdown also increased iNOS expression, consistent with the MH-S cell data. We conclude that increased AM PDE2A is an important negative regulator of macrophage iNOS expression.
Collapse
Affiliation(s)
- Otgonchimeg Rentsendorj
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Franco R D'Alessio
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - David B Pearse
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| |
Collapse
|
9
|
Abstract
OBJECTIVES Recently, recombinant angiotensin-converting enzyme 2 was shown to protect mice from acute lung injury, an effect attributed to reduced bioavailability of angiotensin II. Since angiotensin-converting enzyme 2 metabolizes angiotensin II to angiotensin-(1-7), we hypothesized that this effect is alternatively mediated by angiotensin-(1-7) and activation of its receptor(s). DESIGN To test this hypothesis, we investigated the effects of intravenously infused angiotensin-(1-7) in three experimental models of acute lung injury. SETTING Animal research laboratory. SUBJECTS Male Sprague-Dawley rats, Balb/c mice, and C57Bl6/J mice. INTERVENTIONS Angiotensin-(1-7) was administered with ventilator- or acid aspiration-induced lung injury in mice or 30 minutes after oleic acid infusion in rats. In vitro, the effect of angiotensin-(1-7) on transendothelial electrical resistance of human pulmonary microvascular endothelial cells was analyzed. MEASUREMENTS AND MAIN RESULTS Infusion of angiotensin-(1-7) starting 30 minutes after oleic acid administration protected rats from acute lung injury as evident by reduced lung edema, myeloperoxidase activity, histological lung injury score, and pulmonary vascular resistance while systemic arterial pressure was stabilized. Such effects were largely reproduced by the nonpeptidic angiotensin-(1-7) analog AVE0991. Infusion of angiotensin-(1-7) was equally protective in murine models of ventilator- or acid aspiration-induced lung injury. In the oleic acid model, the two distinct angiotensin-(1-7) receptor blockers A779 and D-Pro-angiotensin-(1-7) reversed the normalizing effects of angiotensin-(1-7) on systemic and pulmonary hemodynamics, but only D-Pro-angiotensin-(1-7) blocked the protection from lung edema and protein leak, whereas A779 restored the infiltration of neutrophils. Rats were also protected from acute lung injury by the AT1 antagonist irbesartan; however, this effect was again blocked by A779 and D-Pro-angiotensin-(1-7). In vitro, angiotensin-(1-7) protected pulmonary microvascular endothelial cells from thrombin-induced barrier failure, yet D-Pro-angiotensin-(1-7) or NO synthase inhibition blocked this effect. CONCLUSIONS Angiotensin-(1-7) or its analogs attenuate the key features of acute lung injury and may present a promising therapeutic strategy for the treatment of this disease.
Collapse
|
10
|
Herold S, Gabrielli NM, Vadász I. Novel concepts of acute lung injury and alveolar-capillary barrier dysfunction. Am J Physiol Lung Cell Mol Physiol 2013; 305:L665-81. [PMID: 24039257 DOI: 10.1152/ajplung.00232.2013] [Citation(s) in RCA: 137] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
In this review we summarize recent major advances in our understanding on the molecular mechanisms, mediators, and biomarkers of acute lung injury (ALI) and alveolar-capillary barrier dysfunction, highlighting the role of immune cells, inflammatory and noninflammatory signaling events, mechanical noxae, and the affected cellular and molecular entities and functions. Furthermore, we address novel aspects of resolution and repair of ALI, as well as putative candidates for treatment of ALI, including pharmacological and cellular therapeutic means.
Collapse
Affiliation(s)
- Susanne Herold
- Dept. of Internal Medicine, Justus Liebig Univ., Universities of Giessen and Marburg Lung Center, Klinikstrasse 33, 35392 Giessen, Germany.
| | | | | |
Collapse
|
11
|
Balczon R, Prasain N, Ochoa C, Prater J, Zhu B, Alexeyev M, Sayner S, Frank DW, Stevens T. Pseudomonas aeruginosa exotoxin Y-mediated tau hyperphosphorylation impairs microtubule assembly in pulmonary microvascular endothelial cells. PLoS One 2013; 8:e74343. [PMID: 24023939 PMCID: PMC3762819 DOI: 10.1371/journal.pone.0074343] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 08/01/2013] [Indexed: 12/21/2022] Open
Abstract
Pseudomonas aeruginosa uses a type III secretion system to introduce the adenylyl and guanylyl cyclase exotoxin Y (ExoY) into the cytoplasm of endothelial cells. ExoY induces Tau hyperphosphorylation and insolubility, microtubule breakdown, barrier disruption and edema, although the mechanism(s) responsible for microtubule breakdown remain poorly understood. Here we investigated both microtubule behavior and centrosome activity to test the hypothesis that ExoY disrupts microtubule dynamics. Fluorescence microscopy determined that infected pulmonary microvascular endothelial cells contained fewer microtubules than control cells, and further studies demonstrated that the microtubule-associated protein Tau was hyperphosphorylated following infection and dissociated from microtubules. Disassembly/reassembly studies determined that microtubule assembly was disrupted in infected cells, with no detectable effects on either microtubule disassembly or microtubule nucleation by centrosomes. This effect of ExoY on microtubules was abolished when the cAMP-dependent kinase phosphorylation site (Ser-214) on Tau was mutated to a non-phosphorylatable form. These studies identify Tau in microvascular endothelial cells as the target of ExoY in control of microtubule architecture following pulmonary infection by Pseudomonas aeruginosa and demonstrate that phosphorylation of tau following infection decreases microtubule assembly.
Collapse
Affiliation(s)
- Ron Balczon
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, Alabama, United States of America
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States of America
- * E-mail:
| | - Nutan Prasain
- Department of Pediatrics, University of Indiana School of Medicine, Indianapolis, Indiana, United States of America
| | - Cristhiaan Ochoa
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States of America
- Department of Pharmacology, University of South Alabama, Mobile, Alabama, United States of America
| | - Jason Prater
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States of America
- Department of Medicine, University of South Alabama, Mobile, Alabama, United States of America
| | - Bing Zhu
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States of America
- Department of Pharmacology, University of South Alabama, Mobile, Alabama, United States of America
| | - Mikhail Alexeyev
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, Alabama, United States of America
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States of America
| | - Sarah Sayner
- Department of Cell Biology and Neuroscience, University of South Alabama, Mobile, Alabama, United States of America
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States of America
| | - Dara W. Frank
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, Wisconsin, United States of America
| | - Troy Stevens
- Center for Lung Biology, University of South Alabama, Mobile, Alabama, United States of America
- Department of Pharmacology, University of South Alabama, Mobile, Alabama, United States of America
- Department of Medicine, University of South Alabama, Mobile, Alabama, United States of America
| |
Collapse
|
12
|
Wang WZ, Jones AW, Wang M, Durante W, Korthuis RJ. Preconditioning with soluble guanylate cyclase activation prevents postischemic inflammation and reduces nitrate tolerance in heme oxygenase-1 knockout mice. Am J Physiol Heart Circ Physiol 2013; 305:H521-32. [PMID: 23771693 DOI: 10.1152/ajpheart.00810.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previously we have shown that, unlike wild-type mice (WT), heme oxygenase-1 knockout (HO-1-/-) mice developed nitrate tolerance and were not protected from inflammation caused by ischemia-reperfusion (I/R) when preconditioned with a H2S donor. We hypothesized that stimulation (with BAY 41-2272) or activation (with BAY 60-2770) of soluble guanylate cyclase (sGC) would precondition HO-1-/- mice against an inflammatory effect of I/R and increase arterial nitrate responses. Intravital fluorescence microscopy was used to visualize leukocyte rolling and adhesion to postcapillary venules of the small intestine in anesthetized mice. Relaxation to ACh and BAY compounds was measured on superior mesenteric arteries isolated after I/R protocols. Preconditioning with either BAY compound 10 min (early phase) or 24 h (late phase) before I/R reduced postischemic leukocyte rolling and adhesion to sham control levels and increased superior mesenteric artery responses to ACh, sodium nitroprusside, and BAY 41-2272 in WT and HO-1-/- mice. Late-phase preconditioning with BAY 60-2770 was maintained in HO-1-/- and endothelial nitric oxide synthase knockout mice pretreated with an inhibitor (dl-propargylglycine) of enzymatically produced H2S. Pretreatment with BAY compounds also prevented the I/R increase in small intestinal TNF-α. We speculate that increasing sGC activity and related PKG acts downstream to H2S and disrupts signaling processes triggered by I/R in part by maintaining low cellular Ca²⁺. In addition, BAY preconditioning did not increase sGC levels, yet increased the response to agents that act on reduced heme-containing sGC. Collectively these actions would contribute to increased nitrate sensitivity and vascular function.
Collapse
Affiliation(s)
- Walter Z Wang
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; and
| | | | | | | | | |
Collapse
|
13
|
McVey M, Tabuchi A, Kuebler WM. Microparticles and acute lung injury. Am J Physiol Lung Cell Mol Physiol 2012; 303:L364-81. [PMID: 22728467 DOI: 10.1152/ajplung.00354.2011] [Citation(s) in RCA: 111] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The pathophysiology of acute lung injury (ALI) and its most severe form, acute respiratory distress syndrome (ARDS), is characterized by increased vascular and epithelial permeability, hypercoagulation and hypofibrinolysis, inflammation, and immune modulation. These detrimental changes are orchestrated by cross talk between a complex network of cells, mediators, and signaling pathways. A rapidly growing number of studies have reported the appearance of distinct populations of microparticles (MPs) in both the vascular and alveolar compartments in animal models of ALI/ARDS or respective patient populations, where they may serve as diagnostic and prognostic biomarkers. MPs are small cytosolic vesicles with an intact lipid bilayer that can be released by a variety of vascular, parenchymal, or blood cells and that contain membrane and cytosolic proteins, organelles, lipids, and RNA supplied from and characteristic for their respective parental cells. Owing to this endowment, MPs can effectively interact with other cell types via fusion, receptor-mediated interaction, uptake, or mediator release, thereby acting as intrinsic stimulators, modulators, or even attenuators in a variety of disease processes. This review summarizes current knowledge on the formation and potential functional role of different MPs in inflammatory diseases with a specific focus on ALI/ARDS. ALI has been associated with the formation of MPs from such diverse cellular origins as platelets, neutrophils, monocytes, lymphocytes, red blood cells, and endothelial and epithelial cells. Because of their considerable heterogeneity in terms of origin and functional properties, MPs may contribute via both harmful and beneficial effects to the characteristic pathological features of ALI/ARDS. A better understanding of the formation, function, and relevance of MPs may give rise to new promising therapeutic strategies to modulate coagulation, inflammation, endothelial function, and permeability either through removal or inhibition of "detrimental" MPs or through administration or stimulation of "favorable" MPs.
Collapse
Affiliation(s)
- Mark McVey
- The Keenan Research Centre, Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, Ontario, Canada
| | | | | |
Collapse
|
14
|
Ochoa CD, Alexeyev M, Pastukh V, Balczon R, Stevens T. Pseudomonas aeruginosa exotoxin Y is a promiscuous cyclase that increases endothelial tau phosphorylation and permeability. J Biol Chem 2012; 287:25407-18. [PMID: 22637478 DOI: 10.1074/jbc.m111.301440] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Exotoxin Y (ExoY) is a type III secretion system effector found in ~ 90% of the Pseudomonas aeruginosa isolates. Although it is known that ExoY causes inter-endothelial gaps and vascular leak, the mechanisms by which this occurs are poorly understood. Using both a bacteria-delivered and a codon-optimized conditionally expressed ExoY, we report that this toxin is a dual soluble adenylyl and guanylyl cyclase that results in intracellular cAMP and cGMP accumulation. The enzymatic activity of ExoY caused phosphorylation of endothelial Tau serine 214, accumulation of insoluble Tau, inter-endothelial cell gap formation, and increased macromolecular permeability. To discern whether the cAMP or cGMP signal was responsible for Tau phosphorylation and barrier disruption, pulmonary microvascular endothelial cells were engineered for the conditional expression of either wild-type guanylyl cyclase, which synthesizes cGMP, or a mutated guanylyl cyclase, which synthesizes cAMP. Sodium nitroprusside stimulation of the cGMP-generating cyclase resulted in transient Tau serine 214 phosphorylation and gap formation, whereas stimulation of the cAMP-generating cyclase induced a robust increase in Tau serine 214 phosphorylation, gap formation, and macromolecular permeability. These results indicate that the cAMP signal is the dominant stimulus for Tau phosphorylation. Hence, ExoY is a promiscuous cyclase and edema factor that uses cAMP and, to some extent, cGMP to induce the hyperphosphorylation and insolubility of endothelial Tau. Because hyperphosphorylated and insoluble Tau are hallmarks in neurodegenerative tauopathies such as Alzheimer disease, acute Pseudomonas infections cause a pathophysiological sequela in endothelium previously recognized only in chronic neurodegenerative diseases.
Collapse
Affiliation(s)
- Cristhiaan D Ochoa
- Department of Pharmacology, College of Medicine, University of South Alabama, Mobile, Alabama 36688, USA
| | | | | | | | | |
Collapse
|
15
|
Dull RO, Cluff M, Kingston J, Hill D, Chen H, Hoehne S, Malleske DT, Kaur R. Lung heparan sulfates modulate K(fc) during increased vascular pressure: evidence for glycocalyx-mediated mechanotransduction. Am J Physiol Lung Cell Mol Physiol 2011; 302:L816-28. [PMID: 22160307 DOI: 10.1152/ajplung.00080.2011] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lung endothelial cells respond to changes in vascular pressure through mechanotransduction pathways that alter barrier function via non-Starling mechanism(s). Components of the endothelial glycocalyx have been shown to participate in mechanotransduction in vitro and in systemic vessels, but the glycocalyx's role in mechanosensing and pulmonary barrier function has not been characterized. Mechanotransduction pathways may represent novel targets for therapeutic intervention during states of elevated pulmonary pressure such as acute heart failure, fluid overload, and mechanical ventilation. Our objective was to assess the effects of increasing vascular pressure on whole lung filtration coefficient (K(fc)) and characterize the role of endothelial heparan sulfates in mediating mechanotransduction and associated increases in K(fc). Isolated perfused rat lung preparation was used to measure K(fc) in response to changes in vascular pressure in combination with superimposed changes in airway pressure. The roles of heparan sulfates, nitric oxide, and reactive oxygen species were investigated. Increases in capillary pressure altered K(fc) in a nonlinear relationship, suggesting non-Starling mechanism(s). nitro-l-arginine methyl ester and heparanase III attenuated the effects of increased capillary pressure on K(fc), demonstrating active mechanotransduction leading to barrier dysfunction. The nitric oxide (NO) donor S-nitrosoglutathione exacerbated pressure-mediated increase in K(fc). Ventilation strategies altered lung NO concentration and the K(fc) response to increases in vascular pressure. This is the first study to demonstrate a role for the glycocalyx in whole lung mechanotransduction and has important implications in understanding the regulation of vascular permeability in the context of vascular pressure, fluid status, and ventilation strategies.
Collapse
Affiliation(s)
- Randal O Dull
- Department of Anesthesiology, Lung Vascular Biology Laboratory, University of Utah School of Medicine, Salt Lake City, UT 84132-2304, USA.
| | | | | | | | | | | | | | | |
Collapse
|