1
|
Karki P, Birukova AA. Microtubules as Major Regulators of Endothelial Function: Implication for Lung Injury. Front Physiol 2021; 12:758313. [PMID: 34777018 PMCID: PMC8582326 DOI: 10.3389/fphys.2021.758313] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/06/2021] [Indexed: 01/04/2023] Open
Abstract
Endothelial dysfunction has been attributed as one of the major complications in COVID-19 patients, a global pandemic that has already caused over 4 million deaths worldwide. The dysfunction of endothelial barrier is characterized by an increase in endothelial permeability and inflammatory responses, and has even broader implications in the pathogenesis of acute respiratory syndromes such as ARDS, sepsis and chronic illnesses represented by pulmonary arterial hypertension and interstitial lung disease. The structural integrity of endothelial barrier is maintained by cytoskeleton elements, cell-substrate focal adhesion and adhesive cell junctions. Agonist-mediated changes in endothelial permeability are directly associated with reorganization of actomyosin cytoskeleton leading to cell contraction and opening of intercellular gaps or enhancement of cortical actin cytoskeleton associated with strengthening of endothelial barrier. The role of actin cytoskeleton remodeling in endothelial barrier regulation has taken the central stage, but the impact of microtubules in this process remains less explored and under-appreciated. This review will summarize the current knowledge on the crosstalk between microtubules dynamics and actin cytoskeleton remodeling, describe the signaling mechanisms mediating this crosstalk, discuss epigenetic regulation of microtubules stability and its nexus with endothelial barrier maintenance, and overview a role of microtubules in targeted delivery of signaling molecules regulating endothelial permeability and inflammation.
Collapse
Affiliation(s)
- Pratap Karki
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Anna A Birukova
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, MD, United States
| |
Collapse
|
2
|
Karki P, Ke Y, Zhang CO, Li Y, Tian Y, Son S, Yoshimura A, Kaibuchi K, Birukov KG, Birukova AA. SOCS3-microtubule interaction via CLIP-170 and CLASP2 is critical for modulation of endothelial inflammation and lung injury. J Biol Chem 2021; 296:100239. [PMID: 33372035 PMCID: PMC7949054 DOI: 10.1074/jbc.ra120.014232] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 11/23/2020] [Accepted: 12/28/2020] [Indexed: 12/12/2022] Open
Abstract
Proinflammatory cytokines such as IL-6 induce endothelial cell (EC) barrier disruption and trigger an inflammatory response in part by activating the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. The protein suppressor of cytokine signaling-3 (SOCS3) is a negative regulator of JAK-STAT, but its role in modulation of lung EC barrier dysfunction caused by bacterial pathogens has not been investigated. Using human lung ECs and EC-specific SOCS3 knockout mice, we tested the hypothesis that SOCS3 confers microtubule (MT)-mediated protection against endothelial dysfunction. SOCS3 knockdown in cultured ECs or EC-specific SOCS3 knockout in mice resulted in exacerbated lung injury characterized by increased permeability and inflammation in response to IL-6 or heat-killed Staphylococcus aureus (HKSA). Ectopic expression of SOCS3 attenuated HKSA-induced EC dysfunction, and this effect required assembled MTs. SOCS3 was enriched in the MT fractions, and treatment with HKSA disrupted SOCS3-MT association. We discovered that-in addition to its known partners gp130 and JAK2-SOCS3 interacts with MT plus-end binding proteins CLIP-170 and CLASP2 via its N-terminal domain. The resulting SOCS3-CLIP-170/CLASP2 complex was essential for maximal SOCS3 anti-inflammatory effects. Both IL-6 and HKSA promoted MT disassembly and disrupted SOCS3 interaction with CLIP-170 and CLASP2. Moreover, knockdown of CLIP-170 or CLASP2 impaired SOCS3-JAK2 interaction and abolished the anti-inflammatory effects of SOCS3. Together, these findings demonstrate for the first time an interaction between SOCS3 and CLIP-170/CLASP2 and reveal that this interaction is essential to the protective effects of SOCS3 in lung endothelium.
Collapse
Affiliation(s)
- Pratap Karki
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yunbo Ke
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Chen-Ou Zhang
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yue Li
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Yufeng Tian
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Sophia Son
- Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois, USA
| | - Akihiko Yoshimura
- Department of Microbiology and Immunology, Keio University, Tokyo, Japan
| | - Kozo Kaibuchi
- Department of Cell Pharmacology, Nagoya University, Nagoya, Japan
| | - Konstantin G Birukov
- Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Anna A Birukova
- Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland, USA.
| |
Collapse
|
3
|
Li Y, Cui X, Shiloach J, Wang J, Suffredini DA, Xu W, Liu W, Fitz Y, Sun J, Eichacker PQ. Hydrocortisone decreases lethality and inflammatory cytokine and nitric oxide production in rats challenged with B. anthracis cell wall peptidoglycan. Intensive Care Med Exp 2020; 8:67. [PMID: 33206255 PMCID: PMC7674536 DOI: 10.1186/s40635-020-00358-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Accepted: 11/06/2020] [Indexed: 11/16/2022] Open
Abstract
Background Lethal B. anthracis infection produces high proinflammatory peptidoglycan (PGN) burdens in hosts. We investigated whether the lethality and inflammation anthrax PGN can produce are related. Methods At 6 h before and the start of 24 h anthrax PGN infusions, rats (n = 198) were treated with diluent (controls) or one of three IV-doses of either hydrocortisone (125, 12.5 or 1.25 mg/kg) or TNF-soluble receptor (TNFsr; 2000, 1000 or 333 μg/kg), non-selective and selective anti-inflammatory agents, respectively. Results Compared to controls, hydrocortisone 125 and 12.5 mg/kg each decreased 7-day lethality (p ≤ 0.004). Hydrocortisone 125 mg/kg decreased IL-1β, IL-6, TNFα, MCP, MIP-1α, MIP-2, RANTES and nitric oxide (NO) blood levels at 4 and 24 h after starting PGN (except MCP at 24 h). Each decrease was significant at 4 h (except MIP-1α that was significant at 24 h) (p ≤ 0.05). Similarly, hydrocortisone 12.5 mg/kg decreased each measure at 4, 24 and 48 h (except TNFα at 24 h and MIP-1α at 24 and 48 h and NO at 48 h). Decreases were significant for IL-6 and NO at 4 h and RANTES at 48 h (p ≤ 0.05). Hydrocortisone 1.25 mg/kg had non-significant effects. Each TNFsr dose decreased lethality but non-significantly. However, when doses were analyzed together, TNFsr decreased lethality in a potential trend (p = 0.16) and IL-6 and NO significantly at 4 h (p = 0.05). Conclusions Peptidoglycan-stimulated host inflammation may contribute to B. anthracis lethality.
Collapse
Affiliation(s)
- Yan Li
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Xizhong Cui
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Joseph Shiloach
- Biotechnology Core Laboratory, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Jeffrey Wang
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Dante A Suffredini
- Section of Critical Care, Department of Medicine, St. Agnes Hospital, Baltimore, MD, 21229, USA
| | - Wanying Xu
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Wancang Liu
- Biotechnology Core Laboratory, National Institute of Diabetes, Digestive, and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892, USA
| | - Yvonne Fitz
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Junfeng Sun
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA
| | - Peter Q Eichacker
- Critical Care Medicine Department, NIH Clinical Center, National Institutes of Health, Building 10, Room 2C145, 10 Center Drive, Bethesda, MD, 20892, USA.
| |
Collapse
|
4
|
Joo E, Olson MF. Regulation and functions of the RhoA regulatory guanine nucleotide exchange factor GEF-H1. Small GTPases 2020; 12:358-371. [PMID: 33126816 PMCID: PMC8583009 DOI: 10.1080/21541248.2020.1840889] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Since the discovery by Madaule and Axel in 1985 of the first Ras homologue (Rho) protein in Aplysia and its human orthologue RhoB, membership in the Rho GTPase family has grown to 20 proteins, with representatives in all eukaryotic species. These GTPases are molecular switches that cycle between active (GTP bound) and inactivate (GDP bound) states. The exchange of GDP for GTP on Rho GTPases is facilitated by guanine exchange factors (GEFs). Approximately 80 Rho GEFs have been identified to date, and only a few GEFs associate with microtubules. The guanine nucleotide exchange factor H1, GEF-H1, is a unique GEF that associates with microtubules and is regulated by the polymerization state of microtubule networks. This review summarizes the regulation and functions of GEF-H1 and discusses the roles of GEF-H1 in human diseases.
Collapse
Affiliation(s)
- Emily Joo
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| | - Michael F Olson
- Department of Chemistry and Biology, Ryerson University, Toronto, ON, Canada
| |
Collapse
|
5
|
Sun Z, Li L, Qu J, Li H, Chen H. Proteomic analysis of therapeutic effects of Qingyi pellet on rodent severe acute pancreatitis-associated lung injury. Biomed Pharmacother 2019; 118:109300. [DOI: 10.1016/j.biopha.2019.109300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Revised: 07/25/2019] [Accepted: 07/31/2019] [Indexed: 12/13/2022] Open
|
6
|
Karki P, Ke Y, Tian Y, Ohmura T, Sitikov A, Sarich N, Montgomery CP, Birukova AA. Staphylococcus aureus-induced endothelial permeability and inflammation are mediated by microtubule destabilization. J Biol Chem 2019; 294:3369-3384. [PMID: 30622143 DOI: 10.1074/jbc.ra118.004030] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 12/13/2018] [Indexed: 12/18/2022] Open
Abstract
Staphylococcus aureus is a major etiological agent of sepsis and induces endothelial cell (EC) barrier dysfunction and inflammation, two major hallmarks of acute lung injury. However, the molecular mechanisms of bacterial pathogen-induced EC barrier disruption are incompletely understood. Here, we investigated the role of microtubules (MT) in the mechanisms of EC barrier compromise caused by heat-killed S. aureus (HKSA). Using a customized monolayer permeability assay in human pulmonary EC and MT fractionation, we observed that HKSA-induced barrier disruption is accompanied by MT destabilization and increased histone deacetylase-6 (HDAC6) activity resulting from elevated reactive oxygen species (ROS) production. Molecular or pharmacological HDAC6 inhibition rescued barrier function in HKSA-challenged vascular endothelium. The HKSA-induced EC permeability was associated with impaired MT-mediated delivery of cytoplasmic linker-associated protein 2 (CLASP2) to the cell periphery, limiting its interaction with adherens junction proteins. HKSA-induced EC barrier dysfunction was also associated with increased Rho GTPase activity via activation of MT-bound Rho-specific guanine nucleotide exchange factor-H1 (GEF-H1) and was abolished by HDAC6 down-regulation. HKSA activated the NF-κB proinflammatory pathway and increased the expression of intercellular and vascular cell adhesion molecules in EC, an effect that was also HDAC6-dependent and mediated, at least in part, by a GEF-H1/Rho-dependent mechanism. Of note, HDAC6 knockout mice or HDAC6 inhibitor-treated WT mice were partially protected from vascular leakage and inflammation caused by both HKSA or methicillin-resistant S. aureus (MRSA). Our results indicate that S. aureus-induced, ROS-dependent up-regulation of HDAC6 activity destabilizes MT and thereby activates the GEF-H1/Rho pathway, increasing both EC permeability and inflammation.
Collapse
Affiliation(s)
- Pratap Karki
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Yunbo Ke
- the Department of Anesthesiology, University of Maryland School of Medicine, Baltimore, Maryland 21201
| | - Yufeng Tian
- the Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, and
| | - Tomomi Ohmura
- the Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, and
| | - Albert Sitikov
- the Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, and
| | - Nicolene Sarich
- the Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, and
| | - Christopher P Montgomery
- the Section of Pulmonary and Critical Care Medicine, Department of Medicine, University of Chicago, Chicago, Illinois 60637, and.,the Department of Critical Care Medicine, Nationwide Children's Hospital, Columbus, Ohio 43205
| | - Anna A Birukova
- From the Division of Pulmonary and Critical Care Medicine, Department of Medicine, University of Maryland School of Medicine, Baltimore, Maryland 21201,
| |
Collapse
|
7
|
Karki P, Birukova AA. Microtubules-associated Rac regulation of endothelial barrier: a role of Asef in acute lung injury. J Investig Med 2017; 65:1089-1092. [PMID: 28923883 DOI: 10.1136/jim-2017-000571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/03/2017] [Indexed: 12/13/2022]
Abstract
The endothelial barrier function regulated by the cytoskeletal reorganizations has been implicated in the pathogenesis of multiple lung diseases including asthma, sepsis, edema, and acute respiratory distress syndrome. The extensive studies have established that activation of small GTPase Rac is a key mechanism in endothelial barrier protection but the role of microtubules-associated Rac in the endothelial functions remains poorly understood. With the emerging evidences that microtubules disassembly also plays a critical role in actin cytoskeleton remodeling leading to endothelial permeability, the knowledge on microtubules-mediated regulation of endothelial barrier is imperative to better understand the etiology of lung injuries as well as to develop novel therapeutics against these disorders. In this regard, our recent studies have revealed some novel aspects of microtubules-mediated regulation of endothelial barrier functions and unraveled a putative role of Rac-specific guanine nucleotide exchange factor Asef in mediating the barrier protective effects of hepatocyte growth factor. In this review, we will discuss the role of this novel Rac activator Asef in endothelial barrier protection and its regulation by microtubules.
Collapse
Affiliation(s)
- Pratap Karki
- Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| | - Anna A Birukova
- Department of Medicine, School of Medicine, University of Maryland, Baltimore, Maryland, USA
| |
Collapse
|
8
|
Mehaffey JH, Charles EJ, Sharma AK, Salmon M, Money D, Schubert S, Stoler MH, Tribble CG, Laubach VE, Roeser ME, Kron IL. Ex Vivo Lung Perfusion Rehabilitates Sepsis-Induced Lung Injury. Ann Thorac Surg 2017; 103:1723-1729. [PMID: 28434548 DOI: 10.1016/j.athoracsur.2017.01.018] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Revised: 12/08/2016] [Accepted: 01/03/2017] [Indexed: 12/12/2022]
Abstract
BACKGROUND Sepsis is the number one cause of lung injury in adults. Ex vivo lung perfusion (EVLP) is gaining clinical acceptance for donor lung evaluation and rehabilitation and may expand the use of marginal organs for transplantation. We hypothesized that 4 hours of normothermic EVLP would improve compliance and oxygenation in a porcine model of sepsis-induced lung injury. METHODS We used intravenous lipopolysaccharide (LPS) to induce a systemic inflammatory response in a porcine model of lung injury. Two groups of 4 animals each received a 2-hour infusion of LPS through the external jugular vein. Serial measurements of blood gases were performed every 30 minutes until the partial pressure of oxygen/fraction of inspired oxygen ratio dropped below 150 on two consecutive readings. Lungs were then randomized to treatment with 4 hours of normothermic EVLP with STEEN Solution (XVIVO Perfusion Inc, Englewood, CO) or 4 additional hours of in vivo perfusion (control). Airway pressures and blood gases were recorded for calculation of dynamic lung compliance and partial pressure of oxygen/fraction of inspired oxygen ratios. EVLP was performed with hourly recruitment maneuvers and oxygen challenge. RESULTS All animals reached a partial pressure of oxygen/fraction of inspired oxygen ratio of less than 150 mm Hg within 3 hours after start of the LPS infusion. Oxygenation and compliance in the control animals continued to decline during the 4-hour in vivo perfusion period, and 3 of the 4 animals died of severe hypoxia within 4 hours. The EVLP group demonstrated significant improvements hour 1 to hour 4 in oxygenation (365.8 ± 53.0 vs 584.4 ± 21.0 mm Hg, p = 0.02) and dynamic compliance (9.0 ± 2.8 vs 15.0 ± 3.6, p = 0.02 mL/cm H2O). CONCLUSIONS EVLP successfully rehabilitated LPS-induced lung injury in this preclinical porcine model and may thus provide a means to rehabilitate many types of acute lung injury.
Collapse
Affiliation(s)
- J Hunter Mehaffey
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Eric J Charles
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Ashish K Sharma
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Morgan Salmon
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Dustin Money
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Sarah Schubert
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Mark H Stoler
- Department of Pathology, University of Virginia, Charlottesville, Virginia
| | - Curtis G Tribble
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Victor E Laubach
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Mark E Roeser
- Department of Surgery, University of Virginia, Charlottesville, Virginia
| | - Irving L Kron
- Department of Surgery, University of Virginia, Charlottesville, Virginia.
| |
Collapse
|
9
|
Balda MS, Matter K. Tight junctions as regulators of tissue remodelling. Curr Opin Cell Biol 2016; 42:94-101. [PMID: 27236618 DOI: 10.1016/j.ceb.2016.05.006] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2016] [Revised: 05/08/2016] [Accepted: 05/10/2016] [Indexed: 12/20/2022]
Abstract
Formation of tissue barriers by epithelial and endothelial cells requires neighbouring cells to interact via intercellular junctions, which includes tight junctions. Tight junctions form a semipermeable paracellular diffusion barrier and act as signalling hubs that guide cell behaviour and differentiation. Components of tight junctions are also expressed in cell types not forming tight junctions, such as cardiomyocytes, where they associate with facia adherens and/or gap junctions. This review will focus on tight junction proteins and their importance in tissue homeostasis and remodelling with a particular emphasis on what we have learned from animal models and human diseases.
Collapse
Affiliation(s)
- Maria S Balda
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, London, United Kingdom.
| | - Karl Matter
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, London, United Kingdom
| |
Collapse
|
10
|
Millar FR, Summers C, Griffiths MJ, Toshner MR, Proudfoot AG. The pulmonary endothelium in acute respiratory distress syndrome: insights and therapeutic opportunities. Thorax 2016; 71:462-73. [DOI: 10.1136/thoraxjnl-2015-207461] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2015] [Accepted: 02/12/2016] [Indexed: 01/23/2023]
|
11
|
Werner F, Kojonazarov B, Gaßner B, Abeßer M, Schuh K, Völker K, Baba HA, Dahal BK, Schermuly RT, Kuhn M. Endothelial actions of atrial natriuretic peptide prevent pulmonary hypertension in mice. Basic Res Cardiol 2016; 111:22. [PMID: 26909880 PMCID: PMC4766231 DOI: 10.1007/s00395-016-0541-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 02/16/2016] [Indexed: 11/30/2022]
Abstract
The cardiac hormone atrial natriuretic peptide (ANP) regulates systemic and pulmonary arterial blood pressure by activation of its cyclic GMP-producing guanylyl cyclase-A (GC-A) receptor. In the lung, these hypotensive effects were mainly attributed to smooth muscle-mediated vasodilatation. It is unknown whether pulmonary endothelial cells participate in the homeostatic actions of ANP. Therefore, we analyzed GC-A/cGMP signalling in lung endothelial cells and the cause and functional impact of lung endothelial GC-A dysfunction. Western blot and cGMP determinations showed that cultured human and murine pulmonary endothelial cells exhibit prominent GC-A expression and activity which were markedly blunted by hypoxia, a condition known to trigger pulmonary hypertension (PH). To elucidate the consequences of impaired endothelial ANP signalling, we studied mice with genetic endothelial cell-restricted ablation of the GC-A receptor (EC GC-A KO). Notably, EC GC-A KO mice exhibit PH already under resting, normoxic conditions, with enhanced muscularization of small arteries and perivascular infiltration of inflammatory cells. These alterations were aggravated on exposure of mice to chronic hypoxia. Lung endothelial GC-A dysfunction was associated with enhanced expression of angiotensin converting enzyme (ACE) and increased pulmonary levels of Angiotensin II. Angiotensin II/AT1-blockade with losartan reversed pulmonary vascular remodelling and perivascular inflammation of EC GC-A KO mice, and prevented their increment by chronic hypoxia. This experimental study indicates that endothelial effects of ANP are critical to prevent pulmonary vascular remodelling and PH. Chronic endothelial ANP/GC-A dysfunction, e.g. provoked by hypoxia, is associated with activation of the ACE-angiotensin pathway in the lung and PH.
Collapse
Affiliation(s)
- Franziska Werner
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Baktybek Kojonazarov
- Department of Internal Medicine, University of Gießen and Marburg Lung Center (UGMLC), Justus-Liebig University Gießen, Giessen, Germany.,German Center for Lung Research, Heidelberg, Germany
| | - Birgit Gaßner
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Marco Abeßer
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Kai Schuh
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Katharina Völker
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, 97070, Würzburg, Germany
| | - Hideo A Baba
- Institute of Pathology, University Hospital of Essen, University of Duisburg-Essen, Essen, Germany
| | - Bhola K Dahal
- Department of Internal Medicine, University of Gießen and Marburg Lung Center (UGMLC), Justus-Liebig University Gießen, Giessen, Germany.,German Center for Lung Research, Heidelberg, Germany
| | - Ralph T Schermuly
- Department of Internal Medicine, University of Gießen and Marburg Lung Center (UGMLC), Justus-Liebig University Gießen, Giessen, Germany.,German Center for Lung Research, Heidelberg, Germany
| | - Michaela Kuhn
- Physiologisches Institut der Universität Würzburg, Röntgenring 9, 97070, Würzburg, Germany.
| |
Collapse
|