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Breslin JW. Edema and lymphatic clearance: molecular mechanisms and ongoing challenges. Clin Sci (Lond) 2023; 137:1451-1476. [PMID: 37732545 PMCID: PMC11025659 DOI: 10.1042/cs20220314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2023] [Revised: 08/18/2023] [Accepted: 08/31/2023] [Indexed: 09/22/2023]
Abstract
Resolution of edema remains a significant clinical challenge. Conditions such as traumatic shock, sepsis, or diabetes often involve microvascular hyperpermeability, which leads to tissue and organ dysfunction. Lymphatic insufficiency due to genetic causes, surgical removal of lymph nodes, or infections, leads to varying degrees of tissue swelling that impair mobility and immune defenses. Treatment options are limited to management of edema as there are no specific therapeutics that have demonstrated significant success for ameliorating microvascular leakage or impaired lymphatic function. This review examines current knowledge about the physiological, cellular, and molecular mechanisms that control microvascular permeability and lymphatic clearance, the respective processes for interstitial fluid formation and removal. Clinical conditions featuring edema, along with potential future directions are discussed.
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Affiliation(s)
- Jerome W Breslin
- Department of Molecular Pharmacology and Physiology, Morsani College of Medicine, University of South Florida, FL, U.S.A
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2
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Ostrom KF, LaVigne JE, Brust TF, Seifert R, Dessauer CW, Watts VJ, Ostrom RS. Physiological Roles of Mammalian Transmembrane Adenylyl Cyclase Isoforms. Physiol Rev 2021; 102:815-857. [PMID: 34698552 DOI: 10.1152/physrev.00013.2021] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adenylyl cyclases (ACs) catalyze the conversion of ATP to the ubiquitous second messenger cAMP. Mammals possess nine isoforms of transmembrane ACs, dubbed AC1-9, that serve as major effector enzymes of G protein-coupled receptors. The transmembrane ACs display varying expression patterns across tissues, giving potential for them having a wide array of physiologic roles. Cells express multiple AC isoforms, implying that ACs have redundant functions. Furthermore, all transmembrane ACs are activated by Gαs so it was long assumed that all ACs are activated by Gαs-coupled GPCRs. AC isoforms partition to different microdomains of the plasma membrane and form prearranged signaling complexes with specific GPCRs that contribute to cAMP signaling compartments. This compartmentation allows for a diversity of cellular and physiological responses by enabling unique signaling events to be triggered by different pools of cAMP. Isoform specific pharmacological activators or inhibitors are lacking for most ACs, making knockdown and overexpression the primary tools for examining the physiological roles of a given isoform. Much progress has been made in understanding the physiological effects mediated through individual transmembrane ACs. GPCR-AC-cAMP signaling pathways play significant roles in regulating functions of every cell and tissue, so understanding each AC isoform's role holds potential for uncovering new approaches for treating a vast array of pathophysiological conditions.
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Affiliation(s)
- Katrina F Ostrom
- W. M. Keck Science Department, Claremont McKenna College, Claremont, CA, United States
| | - Justin E LaVigne
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States
| | - Tarsis F Brust
- Department of Pharmaceutical Sciences, Palm Beach Atlantic University, West Palm Beach, FL, United States
| | - Roland Seifert
- Institute of Pharmacology, Hannover Medical School, Hannover, Germany
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, McGovern Medical School, The University of Texas Health Sciences Center at Houston, Houston, Texas, United States
| | - Val J Watts
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN, United States.,Purdue Institute for Drug Discovery, Purdue University, West Lafayette, IN, United States.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN, United States
| | - Rennolds S Ostrom
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA, United States
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3
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cAMP Compartmentalization in Cerebrovascular Endothelial Cells: New Therapeutic Opportunities in Alzheimer's Disease. Cells 2021; 10:cells10081951. [PMID: 34440720 PMCID: PMC8392343 DOI: 10.3390/cells10081951] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 07/19/2021] [Accepted: 07/28/2021] [Indexed: 12/20/2022] Open
Abstract
The vascular hypothesis used to explain the pathophysiology of Alzheimer’s disease (AD) suggests that a dysfunction of the cerebral microvasculature could be the beginning of alterations that ultimately leads to neuronal damage, and an abnormal increase of the blood–brain barrier (BBB) permeability plays a prominent role in this process. It is generally accepted that, in physiological conditions, cyclic AMP (cAMP) plays a key role in maintaining BBB permeability by regulating the formation of tight junctions between endothelial cells of the brain microvasculature. It is also known that intracellular cAMP signaling is highly compartmentalized into small nanodomains and localized cAMP changes are sufficient at modifying the permeability of the endothelial barrier. This spatial and temporal distribution is maintained by the enzymes involved in cAMP synthesis and degradation, by the location of its effectors, and by the existence of anchor proteins, as well as by buffers or different cytoplasm viscosities and intracellular structures limiting its diffusion. This review compiles current knowledge on the influence of cAMP compartmentalization on the endothelial barrier and, more specifically, on the BBB, laying the foundation for a new therapeutic approach in the treatment of AD.
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Abstract
There is a growing interest in understanding tissue organization, homeostasis, and inflammation. However, despite an abundance of data, the organizing principles of tissue biology remain poorly defined. Here, we present a perspective on tissue organization based on the relationships between cell types and the functions that they perform. We provide a formal definition of tissue homeostasis as a collection of circuits that regulate specific variables within the tissue environment, and we describe how the functional organization of tissues allows for the maintenance of both tissue and systemic homeostasis. This leads to a natural definition of inflammation as a response to deviations from homeostasis that cannot be reversed by homeostatic mechanisms alone. We describe how inflammatory signals act on the same cellular functions involved in normal tissue organization and homeostasis in order to coordinate emergency responses to perturbations and ultimately return the system to a homeostatic state. Finally, we consider the hierarchy of homeostatic and inflammatory circuits and the implications for the development of inflammatory diseases.
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Affiliation(s)
- Matthew L. Meizlish
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
| | - Ruth A. Franklin
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Current affiliation: Department of Stem Cell and Regenerative Biology, Harvard University, Cambridge, Massachusetts 02138, USA
| | - Xu Zhou
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Current affiliation: Division of Gastroenterology, Boston Children's Hospital, Boston, Massachusetts 02115, USA
| | - Ruslan Medzhitov
- Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA
- Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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5
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Genova T, Gaglioti D, Munaron L. Regulation of Vessel Permeability by TRP Channels. Front Physiol 2020; 11:421. [PMID: 32431625 PMCID: PMC7214926 DOI: 10.3389/fphys.2020.00421] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2020] [Accepted: 04/07/2020] [Indexed: 12/13/2022] Open
Abstract
The vascular endothelium constitutes a semi-permeable barrier between blood and interstitial fluids. Since an augmented endothelial permeability is often associated to pathological states, understanding the molecular basis for its regulation is a crucial biomedical and clinical challenge. This review focuses on the processes controlling paracellular permeability that is the permeation of fluids between adjacent endothelial cells (ECs). Cytosolic calcium changes are often detected as early events preceding the alteration of the endothelial barrier (EB) function. For this reason, great interest has been devoted in the last decades to unveil the molecular mechanisms underlying calcium fluxes and their functional relationship with vessel permeability. Beyond the dicotomic classification between store-dependent and independent calcium entry at the plasma membrane level, the search for the molecular components of the related calcium-permeable channels revealed a difficult task for intrinsic and technical limitations. The contribution of redundant channel-forming proteins including members of TRP superfamily and Orai1, together with the very complex intracellular modulatory pathways, displays a huge variability among tissues and along the vascular tree. Moreover, calcium-independent events could significantly concur to the regulation of vascular permeability in an intricate and fascinating multifactorial framework.
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Affiliation(s)
- Tullio Genova
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Deborah Gaglioti
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
| | - Luca Munaron
- Department of Life Sciences and Systems Biology, University of Turin, Turin, Italy
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6
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Mewes M, Lenders M, Stappers F, Scharnetzki D, Nedele J, Fels J, Wedlich-Söldner R, Brand SM, Schmitz B, Brand E. Soluble adenylyl cyclase (sAC) regulates calcium signaling in the vascular endothelium. FASEB J 2019; 33:13762-13774. [PMID: 31585052 DOI: 10.1096/fj.201900724r] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The vascular endothelium acts as a selective barrier between the bloodstream and extravascular tissues. Intracellular [Ca2+]i signaling is essential for vasoactive agonist-induced stimulation of endothelial cells (ECs), typically including Ca2+ release from the endoplasmic reticulum (ER). Although it is known that interactions of Ca2+ and cAMP as ubiquitous messengers are involved in this process, the individual contribution of cAMP-generating adenylyl cyclases (ACs), including the only soluble AC (sAC; ADCY10), remains less clear. Using life-cell microscopy and plate reader-based [Ca2+]i measurements, we found that human immortalized ECs, primary aortic and cardiac microvascular ECs, and primary vascular smooth muscle cells treated with sAC-specific inhibitor KH7 or anti-sAC-small interfering RNA did not show endogenous or exogenous ATP-induced [Ca2+]i elevation. Of note, a transmembrane AC (tmAC) inhibitor did not prevent ATP-induced [Ca2+]i elevation in ECs. Moreover, l-phenylephrine-dependent constriction of ex vivo mouse aortic ring segments was also reduced by KH7. Analysis of the inositol-1,4,5-trisphosphate (IP3) pathway revealed reduced IP3 receptor phosphorylation after KH7 application, which also prevented [Ca2+]i elevation induced by IP3 receptor agonist adenophostin A. Our results suggest that sAC rather than tmAC controls the agonist-induced ER-dependent Ca2+ response in ECs and may represent a treatment target in arterial hypertension and heart failure.-Mewes, M., Lenders, M., Stappers, F., Scharnetzki, D., Nedele, J., Fels, J., Wedlich-Söldner, R., Brand, S.-M., Schmitz, B., Brand, E. Soluble adenylyl cyclase (sAC) regulates calcium signaling in the vascular endothelium.
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Affiliation(s)
- Mirja Mewes
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Malte Lenders
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Franciska Stappers
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - David Scharnetzki
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Johanna Nedele
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
| | - Johannes Fels
- Institute for Cell Dynamics and Imaging, Medical Faculty, University of Muenster, Muenster, Germany.,Department of Physiology, Pathophysiology, and Toxicology and Center for Biomedical Education and Research (ZBAF), University of Witten/Herdecke, Witten, Germany
| | - Roland Wedlich-Söldner
- Institute for Cell Dynamics and Imaging, Medical Faculty, University of Muenster, Muenster, Germany
| | - Stefan-Martin Brand
- Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease, University Hospital Muenster, Muenster, Germany
| | - Boris Schmitz
- Institute of Sports Medicine, Molecular Genetics of Cardiovascular Disease, University Hospital Muenster, Muenster, Germany
| | - Eva Brand
- Internal Medicine D, Department of Nephrology, Hypertension, and Rheumatology, University Hospital Muenster, Muenster, Germany
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Curtis VF, Cartwright IM, Lee JS, Wang RX, Kao DJ, Lanis JM, Burney KM, Welch N, Hall CHT, Goldberg MS, Campbell EL, Colgan SP. Neutrophils as sources of dinucleotide polyphosphates and metabolism by epithelial ENPP1 to influence barrier function via adenosine signaling. Mol Biol Cell 2018; 29:2687-2699. [PMID: 30188771 PMCID: PMC6249842 DOI: 10.1091/mbc.e18-06-0377] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/20/2018] [Accepted: 08/27/2018] [Indexed: 12/15/2022] Open
Abstract
Extracellular adenosine signaling is established as a protective component in mucosal inflammatory responses. The sources of extracellular adenosine include enzymatic processing from nucleotides, such as ATP and AMP, that can be liberated from a variety of cell types, including infiltrating leukocytes. Here we demonstrate that activated human neutrophils are a source of diadenosine triphosphate (Ap3A), providing an additional source of nucleotides during inflammation. Profiling murine enteroids and intestinal epithelial cell lines revealed that intestinal epithelia prominently express apical and lateral ectonucleotide pyrophosphatase/phosphodiesterase-1 (ENPP1), a member of the ENPP family of enzymes that metabolize diadenosine phosphates, especially Ap3A. Extensions of these studies demonstrated that intestinal epithelia metabolize Ap3A to ADP and AMP, which are further metabolized to adenosine and made available to activate surface adenosine receptors. Using loss and gain of ENPP1 approaches, we revealed that ENPP1 coordinates epithelial barrier formation and promotes epithelial wound healing responses. These studies demonstrate the cooperative metabolism between Ap3A and ENPP1 function to provide a significant source of adenosine, subserving its role in inflammatory resolution.
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Affiliation(s)
- Valerie F. Curtis
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Ian M. Cartwright
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - J. Scott Lee
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Ruth X. Wang
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Daniel J. Kao
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Jordi M. Lanis
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Krista M. Burney
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Nichole Welch
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Caroline H. T. Hall
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Matthew S. Goldberg
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
| | - Eric L. Campbell
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Centre for Experimental Medicine, Queen’s University Belfast, Belfast BT7 1NN, Northern Ireland, UK
| | - Sean P. Colgan
- Mucosal Inflammation Program, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Department of Medicine, University of Colorado Anschutz Medical Campus, Aurora, CO 80045
- Rocky Mountain Veterans Affairs Hospital, Denver, CO 80220
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8
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Phuong TTT, Redmon SN, Yarishkin O, Winter JM, Li DY, Križaj D. Calcium influx through TRPV4 channels modulates the adherens contacts between retinal microvascular endothelial cells. J Physiol 2017; 595:6869-6885. [PMID: 28949006 DOI: 10.1113/jp275052] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Accepted: 09/18/2017] [Indexed: 12/17/2022] Open
Abstract
KEY POINTS Endothelial cells employ transient receptor potential isoform 4 (TRPV4) channels to sense ambient mechanical and chemical stimuli. In retinal microvascular endothelial cells, TRPV4 channels regulate calcium homeostasis, cytoskeletal signalling and the organization of adherens junctional contacts. Intracellular calcium increases induced by TRPV4 agonists include a significant contribution from calcium release from internal stores. Activation of TRPV4 channels regulates retinal endothelial barriers in vitro and in vivo. TRPV4 sensing may provide a feedback mechanism between sensing shear flow and eicosanoid modulators, vascular permeability and contractility at the inner retinal endothelial barrier. ABSTRACT The identity of microvascular endothelial (MVE) mechanosensors that sense blood flow in response to mechanical and chemical stimuli and regulate vascular permeability in the retina is unknown. Using immunohistochemistry, calcium imaging, electrophysiology, impedance measurements and vascular permeability assays, we show that the transient receptor potential isoform 4 (TRPV4) plays a major role in Ca2+ /cation signalling, cytoskeletal remodelling and barrier function in retinal microvasculature in vitro and in vivo. Human retinal MVE cells (HrMVECs) predominantly expressed Trpv1 and Trpv4 transcripts, and TRPV4 was broadly localized to the plasma membrane of cultured cells and intact blood vessels in the inner retina. Treatment with the selective TRPV4 agonist GSK1016790A (GSK101) activated a nonselective cation current, robustly elevated [Ca2+ ]i and reversibly increased the permeability of MVEC monolayers. This was associated with disrupted organization of endothelial F-actin, downregulated expression of occludin and remodelling of adherens contacts consisting of vascular endothelial cadherin (VE-cadherin) and β-catenin. In vivo, GSK101 increased the permeability of retinal blood vessels in wild type but not in TRPV4 knockout mice. Agonist-evoked effects on barrier permeability and cytoskeletal reorganization were antagonized by the selective TRPV4 blocker HC 067047. Human choroidal endothelial cells expressed lower TRPV4 mRNA/protein levels and showed less pronounced agonist-evoked calcium signals compared to MVECs. These findings indicate a major role for TRPV4 in Ca2+ homeostasis and barrier function in human retinal capillaries and suggest that TRPV4 may differentially contribute to the inner vs. outer blood-retinal barrier function.
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Affiliation(s)
- Tam T T Phuong
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Sarah N Redmon
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Oleg Yarishkin
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Jacob M Winter
- Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Dean Y Li
- Department of Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA.,Department of Neurobiology & Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA.,Department of Bioengineering, University of Utah School of Medicine, Salt Lake City, UT, USA
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9
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Ho YT, Adriani G, Beyer S, Nhan PT, Kamm RD, Kah JCY. A Facile Method to Probe the Vascular Permeability of Nanoparticles in Nanomedicine Applications. Sci Rep 2017; 7:707. [PMID: 28386096 PMCID: PMC5429672 DOI: 10.1038/s41598-017-00750-3] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2016] [Accepted: 03/09/2017] [Indexed: 12/22/2022] Open
Abstract
The effectiveness of nanoparticles (NP) in nanomedicine depends on their ability to extravasate from vasculature towards the target tissue. This is determined by their permeability across the endothelial barrier. Unfortunately, a quantitative study of the diffusion permeability coefficients (Pd) of NPs is difficult with in vivo models. Here, we utilize a relevant model of vascular-tissue interface with tunable endothelial permeability in vitro based on microfluidics. Human umbilical vein endothelial cells (HUVECs) grown in microfluidic devices were treated with Angiopoietin 1 and cyclic adenosine monophosphate (cAMP) to vary the Pd of the HUVECs monolayer towards fluorescent polystyrene NPs (pNPs) of different sizes, which was determined from image analysis of their fluorescence intensity when diffusing across the monolayer. Using 70 kDa dextran as a probe, untreated HUVECs yielded a Pd that approximated tumor vasculature while HUVECs treated with 25 μg/mL cAMP had Pd that approximated healthy vasculature in vivo. As the size of pNPs increased, its Pd decreased in tumor vasculature, but remained largely unchanged in healthy vasculature, demonstrating a trend similar to tumor selectivity for smaller NPs. This microfluidic model of vascular-tissue interface can be used in any laboratory to perform quantitative assessment of the tumor selectivity of nanomedicine-based systems.
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Affiliation(s)
- Yan Teck Ho
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore
| | - Giulia Adriani
- BioSyM Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore
| | - Sebastian Beyer
- BioSyM Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore.,Federal Institute for Materials Research and Testing, Germany, Germany
| | - Phan-Thien Nhan
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore.,Department of Mechanical Engineering, National University of Singapore, Singapore, Singapore
| | - Roger D Kamm
- BioSyM Interdisciplinary Research Group, Singapore-MIT Alliance for Research and Technology, Singapore, Singapore. .,Department of Biological Engineering and Department of Mechanical Engineering, Massachusetts Institute of Technology, Massachusetts, USA.
| | - James Chen Yong Kah
- NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore, Singapore. .,Department of Biomedical Engineering, National University of Singapore, Singapore, Singapore.
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10
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Supé S, Kohse F, Gembardt F, Kuebler WM, Walther T. Therapeutic time window for angiotensin-(1-7) in acute lung injury. Br J Pharmacol 2016; 173:1618-28. [PMID: 26895462 DOI: 10.1111/bph.13462] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 02/11/2016] [Accepted: 02/12/2016] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND AND PURPOSE There is presently no proven pharmacological therapy for the acute respiratory distress syndrome. Recently, we and others discovered that the heptapeptide angiotensin-(1-7) [Ang-(1-7)] shows significant beneficial effects in preclinical models of acute lung injury (ALI). Here, we aimed to identify the best time window for Ang-(1-7) administration to protect rats from oleic acid (OA) induced ALI. EXPERIMENTAL APPROACH The effects of i.v. infused Ang-(1-7) were examined over four different time windows before or after induction of ALI in male Sprague-Dawley rats. Haemodynamic effects were continuously monitored, and loss of barrier function, inflammation and lung peptidase activities were measured as experimental endpoints. KEY RESULTS Ang-(1-7) infusion provided the best protection against experimental ALI when administered by continuous infusion starting immediately after 30 min OA infusion till the end of the experiment (30-240 min). Both pretreatment (-60 to 0 min before OA) and short-term therapy (30-90 min) also had beneficial effects although less pronounced than the effects achieved with the optimal therapy window. Starting infusion of Ang-(1-7) 60 min after the end of OA treatment (90-240 min) did not protect barrier function or haemodynamics but still reduced myeloperoxidase activity and increased ACE2/ACE activity ratio respectively. CONCLUSIONS AND IMPLICATIONS Our findings indicate that early initiation of therapy after ALI and continuous drug delivery are most beneficial for optimal therapeutic efficiency of Ang-(1-7) treatment in experimental ALI and, presumably accordingly, in clinical acute respiratory distress syndrome.
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Affiliation(s)
- Stefanie Supé
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Franziska Kohse
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Center for Perinatal Medicine, Clinic of Paediatric Surgery, University of Leipzig, Leipzig, Germany
| | - Florian Gembardt
- Department of Cardiac Pathobiology, Excellence Cluster Cardiopulmonary System, Gießen, Germany.,Department of Nephrology-MK3, University Hospital Dresden, Dresden, Germany
| | - Wolfgang M Kuebler
- Institute of Physiology, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Keenan Research Centre for Biomedical Science, St Michael's Hospital, Toronto, ON, Canada.,Departments of Physiology and Surgery, University of Toronto, Ontario, Canada.,German Heart Institute, Berlin, Germany
| | - Thomas Walther
- Department of Pharmacology and Therapeutics, University College Cork, Cork, Ireland.,Center for Perinatal Medicine, Department of Obstetrics, University of Leipzig, Leipzig, Germany
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11
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Yan K, Gao LN, Cui YL, Zhang Y, Zhou X. The cyclic AMP signaling pathway: Exploring targets for successful drug discovery (Review). Mol Med Rep 2016; 13:3715-23. [PMID: 27035868 PMCID: PMC4838136 DOI: 10.3892/mmr.2016.5005] [Citation(s) in RCA: 122] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 02/08/2016] [Indexed: 12/03/2022] Open
Abstract
During development of disease, complex intracellular signaling pathways regulate an intricate series of events, including resistance to external toxins, the secretion of cytokines and the production of pathological phenomena. Adenosine 3′,5′-cyclic monophosphate (cAMP) is a nucleotide that acts as a key second messenger in numerous signal transduction pathways. cAMP regulates various cellular functions, including cell growth and differentiation, gene transcription and protein expression. This review aimed to provide an understanding of the effects of the cAMP signaling pathway and the associated factors on disease occurrence and development by examining the information from a new perspective. These novel insights aimed to promote the development of novel therapeutic approaches and aid in the development of new drugs.
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Affiliation(s)
- Kuo Yan
- Research Center of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Li-Na Gao
- Research Center of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Yuan-Lu Cui
- Research Center of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Yi Zhang
- Research Center of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
| | - Xin Zhou
- Research Center of Traditional Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin 300193, P.R. China
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12
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Morrow KA, Frank DW, Balczon R, Stevens T. The Pseudomonas aeruginosa Exoenzyme Y: A Promiscuous Nucleotidyl Cyclase Edema Factor and Virulence Determinant. Handb Exp Pharmacol 2016; 238:67-85. [PMID: 28181005 DOI: 10.1007/164_2016_5003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Exoenzyme Y (ExoY) was identified as a component of the Pseudomonas aeruginosa type 3 secretion system secretome in 1998. It is a common contributor to the arsenal of type 3 secretion system effectors, as it is present in approximately 90% of Pseudomonas isolates. ExoY has adenylyl cyclase activity that is dependent upon its association with a host cell cofactor. However, recent evidence indicates that ExoY is not just an adenylyl cyclase; rather, it is a promiscuous cyclase capable of generating purine and pyrimidine cyclic nucleotide monophosphates. ExoY's enzymatic activity causes a characteristic rounding of mammalian cells, due to microtubule breakdown. In endothelium, this cell rounding disrupts cell-to-cell junctions, leading to loss of barrier integrity and an increase in tissue edema. Microtubule breakdown seems to depend upon tau phosphorylation, where the elevation of cyclic nucleotide monophosphates activates protein kinases A and G and causes phosphorylation of endothelial microtubule associated protein tau. Phosphorylation is a stimulus for tau release from microtubules, leading to microtubule instability. Phosphorylated tau accumulates inside endothelium as a high molecular weight, oligomeric form, and is then released from the cell. Extracellular high molecular weight tau causes a transmissible cytotoxicity that significantly hinders cellular repair following infection. Thus, ExoY may contribute to bacterial virulence in at least two ways; first, by microtubule breakdown leading to loss of endothelial cell barrier integrity, and second, by promoting release of a high molecular weight tau cytotoxin that impairs cellular recovery following infection.
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Affiliation(s)
- K Adam Morrow
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL, 36688, USA
- The Center for Lung Biology, University of South Alabama, Mobile, AL, 36688, USA
| | - Dara W Frank
- Department of Microbiology and Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
- Center for Infectious Disease Research, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Ron Balczon
- The Center for Lung Biology, University of South Alabama, Mobile, AL, 36688, USA
- Department of Biochemistry and Molecular Biology, University of South Alabama, Mobile, AL, 36688, USA
| | - Troy Stevens
- Department of Physiology and Cell Biology, University of South Alabama, Mobile, AL, 36688, USA.
- The Center for Lung Biology, University of South Alabama, Mobile, AL, 36688, USA.
- Department of Medicine, University of South Alabama, Mobile, AL, 36688, USA.
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13
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Nickols J, Obiako B, Ramila KC, Putinta K, Schilling S, Sayner SL. Lipopolysaccharide-induced pulmonary endothelial barrier disruption and lung edema: critical role for bicarbonate stimulation of AC10. Am J Physiol Lung Cell Mol Physiol 2015; 309:L1430-7. [PMID: 26475732 DOI: 10.1152/ajplung.00067.2015] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 10/14/2015] [Indexed: 12/11/2022] Open
Abstract
Bacteria-induced sepsis is a common cause of pulmonary endothelial barrier dysfunction and can progress toward acute respiratory distress syndrome. Elevations in intracellular cAMP tightly regulate pulmonary endothelial barrier integrity; however, cAMP signals are highly compartmentalized: whether cAMP is barrier-protective or -disruptive depends on the compartment (plasma membrane or cytosol, respectively) in which the signal is generated. The mammalian soluble adenylyl cyclase isoform 10 (AC10) is uniquely stimulated by bicarbonate and is expressed in pulmonary microvascular endothelial cells (PMVECs). Elevated extracellular bicarbonate increases cAMP in PMVECs to disrupt the endothelial barrier and increase the filtration coefficient (Kf) in the isolated lung. We tested the hypothesis that sepsis-induced endothelial barrier disruption and increased permeability are dependent on extracellular bicarbonate and activation of AC10. Our findings reveal that LPS-induced endothelial barrier disruption is dependent on extracellular bicarbonate: LPS-induced barrier failure and increased permeability are exacerbated in elevated bicarbonate compared with low extracellular bicarbonate. The AC10 inhibitor KH7 attenuated the bicarbonate-dependent LPS-induced barrier disruption. In the isolated lung, LPS failed to increase Kf in the presence of minimal perfusate bicarbonate. An increase in perfusate bicarbonate to the physiological range (24 mM) revealed the LPS-induced increase in Kf, which was attenuated by KH7. Furthermore, in PMVECs treated with LPS for 6 h, there was a dose-dependent increase in AC10 expression. Thus these findings reveal that LPS-induced pulmonary endothelial barrier failure requires bicarbonate activation of AC10.
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Affiliation(s)
- Jordan Nickols
- Department of Physiology and Cell Biology, University South Alabama, Mobile, Alabama
| | - Boniface Obiako
- Department of Pharmacology, University South Alabama, Mobile, Alabama; Center for Lung Biology, University South Alabama, Mobile, Alabama; and
| | - K C Ramila
- Department of Physiology and Cell Biology, University South Alabama, Mobile, Alabama
| | - Kevin Putinta
- Department of Physiology and Cell Biology, University South Alabama, Mobile, Alabama
| | - Sarah Schilling
- University of Applied Sciences Bingen, Bingen am Rhein, Germany
| | - Sarah L Sayner
- Department of Physiology and Cell Biology, University South Alabama, Mobile, Alabama; Center for Lung Biology, University South Alabama, Mobile, Alabama; and
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Lamichhane SP, Arya N, Ojha N, Kohler E, Shastri VP. Glycosaminoglycan-functionalized poly-lactide-co-glycolide nanoparticles: synthesis, characterization, cytocompatibility, and cellular uptake. Int J Nanomedicine 2015; 10:775-89. [PMID: 25632234 PMCID: PMC4304601 DOI: 10.2147/ijn.s73508] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The efficient delivery of chemotherapeutics to the tumor via nanoparticle (NP)-based delivery systems remains a significant challenge. This is compounded by the fact that the tumor is highly dynamic and complex environment composed of a plurality of cell types and extracellular matrix. Since glycosaminoglycan (GAG) production is altered in many diseases (or pathologies), NPs bearing GAG moieties on the surface may confer some unique advantages in interrogating the tumor microenvironment. In order to explore this premise, in the study reported here poly-lactide-co-glycolide (PLGA) NPs in the range of 100-150 nm bearing various proteoglycans were synthesized by a single-step nanoprecipitation and characterized. The surface functionalization of the NPs with GAG moieties was verified using zeta potential measurements and X-ray photoelectron spectroscopy. To establish these GAG-bearing NPs as carriers of therapeutics, cellular toxicity assays were undertaken in lung epithelial adenocarcinoma (A549) cells, human pulmonary microvascular endothelial cells (HPMEC), and renal proximal tubular epithelial cells. In general NPs were well tolerated over a wide concentration range (100-600 μg/mL) by all cell types and were taken up to appreciable extents without any adverse cell response in A549 cells and HPMEC. Further, GAG-functionalized PLGA NPs were taken up to different extents in A459 cells and HPMEC. In both cell systems, the uptake of heparin-modified NPs was diminished by 50%-65% in comparison to that of unmodified PLGA. Interestingly, the uptake of chondroitin sulfate NPs was the highest in both cell systems with 40%-60% higher uptake when compared with that of PLGA, and this represented an almost twofold difference over heparin-modified NPs. These findings suggest that GAG modification can be explored as means of changing the uptake behavior of PLGA NPs and these NP systems have potential in cancer therapy.
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Affiliation(s)
- Surya P Lamichhane
- Institute for Macromolecular Chemistry, University of Freiburg, Freiburg, Germany
| | - Neha Arya
- Institute for Macromolecular Chemistry, University of Freiburg, Freiburg, Germany ; Helmholtz Virtual Institute on "Multifunctional Biomaterials for Medicine", University of Freiburg, Freiburg, Germany
| | - Nirdesh Ojha
- Laboratory for Process Technology, Department of Microsystems Engineering, University of Freiburg, Freiburg, Germany
| | - Esther Kohler
- Institute for Macromolecular Chemistry, University of Freiburg, Freiburg, Germany
| | - V Prasad Shastri
- Institute for Macromolecular Chemistry, University of Freiburg, Freiburg, Germany ; Helmholtz Virtual Institute on "Multifunctional Biomaterials for Medicine", University of Freiburg, Freiburg, Germany ; Centre for Biological Signaling Studies (BIOSS), University of Freiburg, Freiburg, Germany
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15
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Li Q, Chen B, Zeng C, Fan A, Yuan Y, Guo X, Huang X, Huang Q. Differential activation of receptors and signal pathways upon stimulation by different doses of sphingosine-1-phosphate in endothelial cells. Exp Physiol 2014; 100:95-107. [PMID: 25557733 DOI: 10.1113/expphysiol.2014.082149] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2014] [Accepted: 10/21/2014] [Indexed: 01/08/2023]
Abstract
NEW FINDINGS What is the central question of this study? Why do different doses of sphingosine-1-phosphate (S1P) induce distinct biological effects in endothelial cells? What is the main finding and its importance? S1P at physiological concentrations preserved endothelial barrier function by binding to S1P receptor 1, then triggering Ca(2+) release from endoplasmic reticulum through phosphoinositide phospholipase C and inositol triphosphate, and consequently strengthening tight junction and F-actin assembly through Rac1 activation. Excessive S1P induced endothelial malfunction by activating S1P receptor 2 and RhoA/ROCK pathway, causing F-actin and tight junction disorganisation. Extracellular Ca(2+) influx was involved in this process. Sphingosine-1-phosphate (S1P) is a bioactive sphingolipid in plasma, and its plasma concentration can be adjusted through a complex metabolic process. The alterations in S1P levels and the activation of receptors collaboratively regulate distinct biological effects. This study was performed to investigate comparatively the effect of different concentrations of S1P on endothelial barrier function and to explore the roles of S1P receptors (S1PRs), Rho GTPases and calcium in S1P-induced endothelial responses. Endothelial barrier function was studied using transendothelial electric resistance and a resistance meter in human umbilical vein endothelial cells. Specific agonists or antagonists were applied to control the activation of S1P receptors and the release of calcium from different cellular compartments. The results indicated that at physiological concentrations, S1P preserved endothelial barrier function by binding with S1PR1. The activation of S1PR1 triggered the release of intracellular Ca(2+) from the endoplasmic reticulum through the PI-phospholipase C and inositol trisphosphate pathways. Consequently, the Rho GTPase Rac1 was activated, strengthening the assembly of tight junction proteins and F-actin. However, excessive S1P induced endothelial barrier dysfunction by activating S1PR2 followed by the RhoA/RhoA kinase pathway, causing the disorganization of F-actin and the disassembly of the tight junction protein ZO-1. An influx of extracellular Ca(2+) was involved in this process. These data suggest that physiological and excessive amounts of S1P induce different responses in human umbilical vein endothelial cells; the activation of the 1PR1-PLC-IP3 R-Ca(2+) -Rac1 pathway governs the low-dose S1P-enhanced endothelial barrier integrity, and the activation of S1PR2-calcium influx-RhoA/ROCK dominates the high-dose S1P-induced endothelial monolayer hyperpermeability response.
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Affiliation(s)
- Qiang Li
- Department of Pathophysiology, Key Laboratory for Shock and Microcirculation Research of Guangdong Province, Southern Medical University, Guangzhou, 510515, PR China
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16
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Shi L, Zeng M, Fu BM. Temporal effects of vascular endothelial growth factor and 3,5-cyclic monophosphate on blood-brain barrier solute permeability in vivo. J Neurosci Res 2014; 92:1678-89. [PMID: 25066133 DOI: 10.1002/jnr.23457] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2014] [Revised: 06/11/2014] [Accepted: 07/03/2014] [Indexed: 12/11/2022]
Abstract
To test the hypothesis that vascular endothelial growth factor (VEGF) can transiently increase the blood-brain barrier permeability, P, as for peripheral microvessels and that the elevation of 3,5-cyclic monophosphate (cAMP) levels can inhibit the VEGF-induced acute hyperpermeability, we employed multiphoton microscopy to quantify the cerebral microvessel permeability P to various-sized solutes under VEGF and cAMP treatments. The cerebral microcirculation was observed through a section of frontoparietal bone thinned with a microgrinder. Fluorescein (MW 376Da), fluorescein isothioyanate-dextran-20k (FITC-Dex-20k), FITC-Dex-70k, or Alexa Fluor 488-IgG in 1% bovine serum albumin mammalian Ringer's solution was injected into the cerebral circulation via the ipsilateral carotid artery with a syringe pump. Simultaneously, temporal images were collected from the brain parenchyma ∼100-200 μm below the pia mater. P was determined from the rate of tissue solute accumulation around individual microvessels. Exposure to 1 nM VEGF transiently increased P to 2.2, 10.5, 9.8, and 12.8 times control values, for fluorescein, Dex-20k, Dex-70k, and IgG, respectively, within 30 sec, and all returned to control levels within 2 min. After 20 min of pretreatment with 2 mM of the cAMP analog 8-bromo-cAMP, the initial increase by 1 nM VEGF was completely abolished in P of all solutes. The response pattern of P to VEGF and cAMP and the ratios of the peak to control values for rat cerebral microvessels are similar to those for rat mesenteric (peripheral) microvessels, except that the ratios are higher in P of cerebral microvessels for the intermediate and large solutes. These results imply a new approach for delivering large therapeutic agents to the brain.
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Affiliation(s)
- Lingyan Shi
- Department of Biomedical Engineering, The City College of the City University of New York, New York, New York
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17
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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.
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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
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18
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Haidari M, Zhang W, Willerson JT, Dixon RA. Disruption of endothelial adherens junctions by high glucose is mediated by protein kinase C-β-dependent vascular endothelial cadherin tyrosine phosphorylation. Cardiovasc Diabetol 2014; 13:105. [PMID: 25927959 PMCID: PMC4223716 DOI: 10.1186/1475-2840-13-105] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 04/29/2014] [Indexed: 12/17/2022] Open
Abstract
Background Hyperglycemia has been recognized as a primary factor in endothelial barrier dysfunction and in the development of micro- and macrovascular diseases associated with diabetes, but the underlying biochemical mechanisms remain elusive. Tyrosine phosphorylation of vascular endothelial cadherin (VE-cad) leads to the disruption of endothelial adherens junctions and increases the transendothelial migration (TEM) of leukocytes. Methods VE-cad tyrosine phosphorylation, adherens junction integrity and TEM of monocytes in human umbilical vein endothelial cells (HUVECs) treated with high-concentration glucose were evaluated. The role of protein kinase C (PKC) in induction of endothelial cells adherence junction disruption by exposure of HUVECs to high concentration of glucose was explored. Results The treatment of HUVEC with high-concentration glucose increased VE-cad tyrosine phosphorylation, whereas mannitol or 3-O-methyl-D-glucose had no effect. In addition, high-concentration glucose increased the dissociation of the VE-cad–β-catenin complex, activation of the Wnt/β-catenin pathway, and the TEM of monocytes. These alterations were accompanied by the activation of endothelial PKC and increased phosphorylation of ERK and myosin light chain (MLC). High-concentration glucose-induced tyrosine phosphorylation of VE-cad was attenuated by: 1- the inhibition of PKC-β by overexpression of dominant-negative PKC-β 2- inhibition of MLC phosphorylation by overexpression of a nonphosphorylatable dominant-negative form of MLC, 3- the inhibition of actin polymerization by cytochalasin D and 4- the treatment of HUVECs with forskolin (an activator of adenylate cyclase). Conclusions Our findings show that the high-concentration glucose-induced disruption of endothelial adherens junctions is mediated by tyrosine phosphorylation of VE-cad through PKC-β and MLC phosphorylation.
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Affiliation(s)
- Mehran Haidari
- Department of Internal Medicine, Division of Cardiology, The University of Texas Medical School at Houston, 77030, Houston, TX, USA. .,Texas Heart Institute at St. Luke's Episcopal Hospital, PO Box 20345 C1000, 77030, Houston, TX, USA.
| | - Wei Zhang
- Texas Heart Institute at St. Luke's Episcopal Hospital, PO Box 20345 C1000, 77030, Houston, TX, USA.
| | - James T Willerson
- Department of Internal Medicine, Division of Cardiology, The University of Texas Medical School at Houston, 77030, Houston, TX, USA. .,Texas Heart Institute at St. Luke's Episcopal Hospital, PO Box 20345 C1000, 77030, Houston, TX, USA.
| | - Richard Af Dixon
- Texas Heart Institute at St. Luke's Episcopal Hospital, PO Box 20345 C1000, 77030, Houston, TX, USA.
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19
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Villalta PC, Townsley MI. Transient receptor potential channels and regulation of lung endothelial permeability. Pulm Circ 2014; 3:802-15. [PMID: 25006396 DOI: 10.1086/674765] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 08/22/2013] [Indexed: 12/19/2022] Open
Abstract
This review highlights our current knowledge regarding expression of transient receptor potential (TRP) cation channels in lung endothelium and evidence for their involvement in regulation of lung endothelial permeability. Six mammalian TRP families have been identified and organized on the basis of sequence homology: TRPC (canonical), TRPV (vanilloid), TRPM (melastatin), TRPML (mucolipin), TRPP (polycystin), and TRPA (ankyrin). To date, only TRPC1/4, TRPC6, TRPV4, and TRPM2 have been extensively studied in lung endothelium. Calcium influx through each of these channels has been documented to increase lung endothelial permeability, although their channel-gating mechanisms, downstream signaling mechanisms, and impact on endothelial structure and barrier integrity differ. While other members of the TRPC, TRPV, and TRPM families may be expressed in lung endothelium, we have little or no evidence linking these to regulation of lung endothelial permeability. Further, neither the expression nor functional role(s) of any TRPML, TRPP, and TRPA family members has been studied in lung endothelium. In addition to this assessment organized by TRP channel family, we also discuss TRP channels and lung endothelial permeability from the perspective of lung endothelial heterogeneity, using outcomes of studies focused on TRPC1/4 and TRPV4 channels. The diversity within the TRP channel family and the relative paucity of information regarding roles of a number of these channels in lung endothelium make this field ripe for continued investigation.
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Affiliation(s)
- Patricia C Villalta
- Departments of Physiology and Medicine, Center for Lung Biology, University of South Alabama, Mobile, Alabama, USA
| | - Mary I Townsley
- Departments of Physiology and Medicine, Center for Lung Biology, University of South Alabama, Mobile, Alabama, USA
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20
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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.
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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
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Ahmad A, Schaack JB, White CW, Ahmad S. Adenosine A2A receptor-dependent proliferation of pulmonary endothelial cells is mediated through calcium mobilization, PI3-kinase and ERK1/2 pathways. Biochem Biophys Res Commun 2013; 434:566-71. [PMID: 23583199 DOI: 10.1016/j.bbrc.2013.03.115] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 03/26/2013] [Indexed: 12/13/2022]
Abstract
Hypoxia and HIF-2α-dependent A2A receptor expression and activation increase proliferation of human lung microvascular endothelial cells (HLMVECs). This study was undertaken to investigate the signaling mechanisms that mediate the proliferative effects of A2A receptor. A2A receptor-mediated proliferation of HLMVECs was inhibited by intracellular calcium chelation, and by specific inhibitors of ERK1/2 and PI3-kinase (PI3K). The adenosine A2A receptor agonist CGS21680 caused intracellular calcium mobilization in controls and, to a greater extent, in A2A receptor-overexpressing HLMVECs. Adenoviral-mediated A2A receptor overexpression as well as receptor activation by CGS21680 caused increased PI3K activity and Akt phosphorylation. Cells overexpressing A2A receptor also manifested enhanced ERK1/2 phosphorylation upon CGS21680 treatment. A2A receptor activation also caused enhanced cAMP production. Likewise, treatment with 8Br-cAMP increased PI3K activity. Hence A2A receptor-mediated cAMP production and PI3K and Akt phosphorylation are potential mediators of the A2A-mediated proliferative response of HLMVECs. Cytosolic calcium mobilization and ERK1/2 phosphorylation are other critical effectors of HLMVEC proliferation and growth. These studies underscore the importance of adenosine A2A receptor in activation of survival and proliferative pathways in pulmonary endothelial cells that are mediated through PI3K/Akt and ERK1/2 pathways.
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Affiliation(s)
- Aftab Ahmad
- Pediatric Airway Research Center, Department of Pediatrics, Aurora, CO 80045, USA.
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Spatial coordination between cell and nuclear shape within micropatterned endothelial cells. Nat Commun 2012; 3:671. [PMID: 22334074 DOI: 10.1038/ncomms1668] [Citation(s) in RCA: 406] [Impact Index Per Article: 33.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Accepted: 01/09/2012] [Indexed: 12/20/2022] Open
Abstract
Growing evidence suggests that cytoplasmic actin filaments are essential factors in the modulation of nuclear shape and function. However, the mechanistic understanding of the internal orchestration between cell and nuclear shape is still lacking. Here we show that orientation and deformation of the nucleus are regulated by lateral compressive forces driven by tension in central actomyosin fibres. By using a combination of micro-manipulation tools, our study reveals that tension in central stress fibres is gradually generated by anisotropic force contraction dipoles, which expand as the cell elongates and spreads. Our findings indicate that large-scale cell shape changes induce a drastic condensation of chromatin and dramatically affect cell proliferation. On the basis of these findings, we propose a simple mechanical model that quantitatively accounts for our experimental data and provides a conceptual framework for the mechanistic coordination between cell and nuclear shape.
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Makarova AM, Lebedeva TV, Nassar T, Higazi AAR, Xue J, Carinato ME, Bdeir K, Cines DB, Stepanova V. Urokinase-type plasminogen activator (uPA) induces pulmonary microvascular endothelial permeability through low density lipoprotein receptor-related protein (LRP)-dependent activation of endothelial nitric-oxide synthase. J Biol Chem 2011; 286:23044-53. [PMID: 21540184 PMCID: PMC3123072 DOI: 10.1074/jbc.m110.210195] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2010] [Revised: 04/19/2011] [Indexed: 01/11/2023] Open
Abstract
Urokinase plasminogen activator (uPA) and PA inhibitor type 1 (PAI-1) are elevated in acute lung injury, which is characterized by a loss of endothelial barrier function and the development of pulmonary edema. Two-chain uPA and uPA-PAI-1 complexes (1-20 nM) increased the permeability of monolayers of human pulmonary microvascular endothelial cells (PMVECs) in vitro and lung permeability in vivo. The effects of uPA-PAI-1 were abrogated by the nitric-oxide synthase (NOS) inhibitor L-NAME (N(D)-nitro-L-arginine methyl ester). Two-chain uPA (1-20 nM) and uPA-PAI-1 induced phosphorylation of endothelial NOS-Ser(1177) in PMVECs, which was followed by generation of NO and the nitrosylation and dissociation of β-catenin from VE-cadherin. uPA-induced phosphorylation of eNOS was decreased by anti-low density lipoprotein receptor-related protein-1 (LRP) antibody and an LRP antagonist, receptor-associated protein (RAP), and when binding to the uPA receptor was blocked by the isolated growth factor-like domain of uPA. uPA-induced phosphorylation of eNOS was also inhibited by the protein kinase A (PKA) inhibitor, myristoylated PKI, but was not dependent on PI3K-Akt signaling. LRP blockade and inhibition of PKA prevented uPA- and uPA-PAI-1-induced permeability of PMVEC monolayers in vitro and uPA-induced lung permeability in vivo. These studies identify a novel pathway involved in regulating PMVEC permeability and suggest the utility of uPA-based approaches that attenuate untoward permeability following acute lung injury while preserving its salutary effects on fibrinolysis and airway remodeling.
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Affiliation(s)
- Anastasia M. Makarova
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Tatiana V. Lebedeva
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Taher Nassar
- the Department of Clinical Biochemistry, Hebrew University-Hadassah Medical Center, Jerusalem 91120, Israel, and
| | - Abd Al-Roof Higazi
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
- the Department of Clinical Biochemistry, Hebrew University-Hadassah Medical Center, Jerusalem 91120, Israel, and
| | - Jing Xue
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
- the Department of Laboratory Medicine, Tianjin Huanhu Hospital, Tianjin 300060, China
| | - Maria E. Carinato
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Khalil Bdeir
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Douglas B. Cines
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
| | - Victoria Stepanova
- From the Department of Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104
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Rentsendorj O, Damarla M, Aggarwal NR, Choi JY, Johnston L, D'Alessio FR, Crow MT, Pearse DB. Knockdown of lung phosphodiesterase 2A attenuates alveolar inflammation and protein leak in a two-hit mouse model of acute lung injury. Am J Physiol Lung Cell Mol Physiol 2011; 301:L161-70. [PMID: 21571906 DOI: 10.1152/ajplung.00073.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Phosphodiesterase 2A (PDE2A) is stimulated by cGMP to hydrolyze cAMP, a potent endothelial barrier-protective molecule. We previously found that lung PDE2A contributed to a mouse model of ventilator-induced lung injury (VILI). The purpose of the present study was to determine the contribution of PDE2A in a two-hit mouse model of 1-day intratracheal (IT) LPS followed by 4 h of 20 ml/kg tidal volume ventilation. Compared with IT water controls, LPS alone (3.75 μg/g body wt) increased lung PDE2A mRNA and protein expression by 6 h with a persistent increase in protein through day 4 before decreasing to control levels on days 6 and 10. Similar to the PDE2A time course, the peak in bronchoalveolar lavage (BAL) neutrophils, lactate dehydrogenase (LDH), and protein concentration also occurred on day 4 post-LPS. IT LPS (1 day) and VILI caused a threefold increase in lung PDE2A and inducible nitric oxide synthase (iNOS) and a 24-fold increase in BAL neutrophilia. Compared with a control adenovirus, PDE2A knockdown with an adenovirus expressing a short hairpin RNA administered IT 3 days before LPS/VILI effectively decreased lung PDE2A expression and significantly attenuated BAL neutrophilia, LDH, protein, and chemokine levels. PDE2A knockdown also reduced lung iNOS expression by 53%, increased lung cAMP by nearly twofold, and improved survival from 47 to 100%. We conclude that in a mouse model of LPS/VILI, a synergistic increase in lung PDE2A expression increased lung iNOS and alveolar inflammation and contributed significantly to the ensuing acute lung injury.
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Affiliation(s)
- Otgonchimeg Rentsendorj
- Division of Pulmonary and Critical Care Medicine, Department of Medicine, Johns Hopkins Medical Institutions, Baltimore, MD 21224, USA
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Xiao Z, Wang T, Qin H, Huang C, Feng Y, Xia Y. Endoplasmic reticulum Ca2+ release modulates endothelial nitric-oxide synthase via extracellular signal-regulated kinase (ERK) 1/2-mediated serine 635 phosphorylation. J Biol Chem 2011; 286:20100-8. [PMID: 21454579 DOI: 10.1074/jbc.m111.220236] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Endothelial nitric-oxide synthase (eNOS) plays a central role in cardiovascular regulation. eNOS function is critically modulated by Ca(2+) and protein phosphorylation, but the interrelationship between intracellular Ca(2+) mobilization and eNOS phosphorylation is poorly understood. Here we show that endoplasmic reticulum (ER) Ca(2+) release activates eNOS by selectively promoting its Ser-635/633 (bovine/human) phosphorylation. With bovine endothelial cells, thapsigargin-induced ER Ca(2+) release caused a dose-dependent increase in eNOS Ser-635 phosphorylation, leading to elevated NO production. ER Ca(2+) release also promoted eNOS Ser-633 phosphorylation in mouse vessels in vivo. This effect was independent of extracellular Ca(2+) and selective to Ser-635 because the phosphorylation status of other eNOS sites, including Ser-1179 or Thr-497, was unaffected in thapsigargin-treated cells. Blocking ERK1/2 abolished ER Ca(2+) release-induced eNOS Ser-635 phosphorylation, whereas inhibiting protein kinase A or Ca(2+)/calmodulin-dependent protein kinase II had no effect. Protein phosphorylation assay confirmed that ERK1/2 directly phosphorylated the eNOS Ser-635 residue in vitro. Further studies demonstrated that ER Ca(2+) release-induced ERK1/2 activation mediated the enhancing action of purine or bradykinin receptor stimulation on eNOS Ser-635/633 phosphorylation in bovine/human endothelial cells. Mutating the Ser-635 to nonphosphorylatable alanine prevented ATP from activating eNOS in cells. Taken together, these studies reveal that ER Ca(2+) release enhances eNOS Ser-635 phosphorylation and function via ERK1/2 activation. Because ER Ca(2+) is commonly mobilized by agonists or physicochemical stimuli, the identified ER Ca(2+)-ERK1/2-eNOS Ser-635 phosphorylation pathway may have a broad role in the regulation of endothelial function.
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Affiliation(s)
- Zhihong Xiao
- Davis Heart and Lung Research Institute, Division of Cardiovascular Medicine, Department of Molecular and Cellular Biochemistry, The Ohio State University College of Medicine, Columbus, Ohio 43210, USA
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27
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Sayner SL. Emerging themes of cAMP regulation of the pulmonary endothelial barrier. Am J Physiol Lung Cell Mol Physiol 2011; 300:L667-78. [PMID: 21335524 DOI: 10.1152/ajplung.00433.2010] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The presence of excess fluid in the interstitium and air spaces of the lung presents severe restrictions to gas exchange. The pulmonary endothelial barrier regulates the flux of fluid and plasma proteins from the vascular space into the underlying tissue. The integrity of this endothelial barrier is dynamically regulated by transitions in cAMP (3',5'-cyclic adenosine monophosphate), which are synthesized in discrete subcellular compartments. Cyclic AMP generated in the subplasma membrane compartment acts through PKA and Epac (exchange protein directly activated by cAMP) to tighten cell adhesions, strengthen cortical actin, reduce actomyosin contraction, and decrease permeability. Confining cAMP within the subplasma membrane space is critical to its barrier-protective properties. When cAMP escapes the near membrane compartment and gains access to the cytosolic compartment, or when soluble adenylyl cyclases generate cAMP within the cytosolic compartment, this second messenger activates established cytosolic cAMP signaling cascades to perturb the endothelial barrier through PKA-mediated disruption of microtubules. Thus the concept of cAMP compartmentalization in endothelial barrier regulation is gaining momentum and new possibilities are being unveiled for cytosolic cAMP signaling with the emergence of the bicarbonate-regulated mammalian soluble adenylyl cyclase (sAC or AC10).
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Affiliation(s)
- Sarah L Sayner
- Dept. of Cell Biology and Neuroscience, Member, Center for Lung Biology, College of Medicine, Univ. of South Alabama, Mobile, AL 36688, USA.
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28
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Rampersad SN, Ovens JD, Huston E, Umana MB, Wilson LS, Netherton SJ, Lynch MJ, Baillie GS, Houslay MD, Maurice DH. Cyclic AMP phosphodiesterase 4D (PDE4D) Tethers EPAC1 in a vascular endothelial cadherin (VE-Cad)-based signaling complex and controls cAMP-mediated vascular permeability. J Biol Chem 2010; 285:33614-22. [PMID: 20732872 PMCID: PMC2962459 DOI: 10.1074/jbc.m110.140004] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 08/17/2010] [Indexed: 12/28/2022] Open
Abstract
Vascular endothelial cell (VEC) permeability is largely dependent on the integrity of vascular endothelial cadherin (VE-cadherin or VE-Cad)-based intercellular adhesions. Activators of protein kinase A (PKA) or of exchange protein activated by cAMP (EPAC) reduce VEC permeability largely by stabilizing VE-Cad-based intercellular adhesions. Currently, little is known concerning the nature and composition of the signaling complexes that allow PKA or EPAC to regulate VE-Cad-based structures and through these actions control permeability. Using pharmacological, biochemical, and cell biological approaches we identified and determined the composition and functionality of a signaling complex that coordinates cAMP-mediated control of VE-Cad-based adhesions and VEC permeability. Thus, we report that PKA, EPAC1, and cyclic nucleotide phosphodiesterase 4D (PDE4D) enzymes integrate into VE-Cad-based signaling complexes in human arterial endothelial cells. Importantly, we show that protein-protein interactions between EPAC1 and PDE4D serve to foster their integration into VE-Cad-based complexes and allow robust local regulation of EPAC1-based stabilization of VE-Cad-based adhesions. Of potential translational importance, we mapped the EPAC1 peptide motif involved in binding PDE4D and show that a cell-permeable variant of this peptide antagonizes EPAC1-PDE4D binding and directly alters VEC permeability. Collectively, our data indicate that PDE4D regulates both the activity and subcellular localization of EPAC1 and identify a novel mechanism for regulated EPAC1 signaling in these cells.
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Affiliation(s)
| | | | - Elaine Huston
- the Molecular Pharmacology Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - M. Bibiana Umana
- Pharmacology & Toxicology, Queen's University, Kingston, Ontario K7L 3N6, Canada and
| | | | - Stuart J. Netherton
- Pharmacology & Toxicology, Queen's University, Kingston, Ontario K7L 3N6, Canada and
| | - Martin J. Lynch
- the Molecular Pharmacology Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - George S. Baillie
- the Molecular Pharmacology Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Miles D. Houslay
- the Molecular Pharmacology Group, Institute of Biomedical and Life Sciences, University of Glasgow, Glasgow, Scotland, United Kingdom
| | - Donald H. Maurice
- From the Departments of Pathology & Molecular Medicine and
- Pharmacology & Toxicology, Queen's University, Kingston, Ontario K7L 3N6, Canada and
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Zhu B, Zhang L, Creighton J, Alexeyev M, Strada SJ, Stevens T. Protein kinase A phosphorylation of tau-serine 214 reorganizes microtubules and disrupts the endothelial cell barrier. Am J Physiol Lung Cell Mol Physiol 2010; 299:L493-501. [PMID: 20639351 DOI: 10.1152/ajplung.00431.2009] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Intracellular cAMP is compartmentalized to near membrane domains in endothelium, where it strengthens endothelial cell barrier function. Phosphodiesterase 4D4 (PDE4D4) interacts with the spectrin membrane skeleton and prevents cAMP from accessing microtubules. Expression of a dominant-negative PDE4D4 peptide enables cAMP to access microtubules, where it results in phosphorylation of the nonneuronal microtubule-associated protein tau at serine 214. Presently, we sought to determine whether PKA is responsible for tau-Ser214 phosphorylation and furthermore whether PKA phosphorylation of tau-Ser214 is sufficient to reorganize microtubules and induce endothelial cell gaps. In cells expressing the dominant-negative PDE4D4 peptide, forskolin activated transmembrane adenylyl cyclases, increased cAMP, and induced tau-Ser214 phosphorylation that was accompanied by microtubule reorganization. PKA catalytic and regulatory I subunits, but not the regulatory II subunit, coassociated with reorganized microtubules. To determine the functional consequence of tau-Ser214 phosphorylation, wild-type human tau40 and tau40 engineered to possess an alanine point mutation (S214A) were stably expressed in endothelium. In cells expressing the dominant-negative PDE4D4 peptide and tau-S214A, PKA-dependent phosphorylation of both the endogenous and heterologously expressed tau were abolished. Expression of tau-S214A prevented forskolin from depolymerizing microtubules, inducing intercellular gaps, and increasing macromolecular permeability. These findings therefore identify nonneuronal tau as a critical cAMP-responsive microtubule-associated protein that controls microtubule architecture and endothelial cell barrier function.
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Affiliation(s)
- Bing Zhu
- Dept. of Pharmacology, Univ. of South Alabama, Mobile, 36688, USA.
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Ito S, Suki B, Kume H, Numaguchi Y, Ishii M, Iwaki M, Kondo M, Naruse K, Hasegawa Y, Sokabe M. Actin cytoskeleton regulates stretch-activated Ca2+ influx in human pulmonary microvascular endothelial cells. Am J Respir Cell Mol Biol 2009; 43:26-34. [PMID: 19648475 DOI: 10.1165/rcmb.2009-0073oc] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
During high tidal volume mechanical ventilation in patients with acute lung injury (ALI)/acute respiratory distress syndrome (ARDS), regions of the lung are exposed to excessive stretch, causing inflammatory responses and further lung damage. In this study, the effects of mechanical stretch on intracellular Ca(2+) concentration ([Ca(2+)](i)), which regulates a variety of endothelial properties, were investigated in human pulmonary microvascular endothelial cells (HPMVECs). HPMVECs grown on fibronectin-coated silicon chambers were exposed to uniaxial stretching, using a cell-stretching apparatus. After stretching and subsequent unloading, [Ca(2+)](i), as measured by fura-2 fluorescence, was transiently increased in a strain amplitude-dependent manner. The elevation of [Ca(2+)](i) induced by stretch was not evident in the Ca(2+)-free solution and was blocked by Gd(3+), a stretch-activated channel inhibitor, or ruthenium red, a transient receptor potential vanilloid inhibitor. The disruption of actin polymerization with cytochalasin D inhibited the stretch-induced elevation of [Ca(2+)](i). In contrast, increases in [Ca(2+)](i) induced by thapsigargin or thrombin were not affected by cytochalasin D. Increased actin polymerization with sphingosine-1-phosphate or jasplakinolide enhanced the stretch-induced elevation of [Ca(2+)](i). A simple network model of the cytoskeleton was also developed in support of the notion that actin stress fibers are required for efficient force transmission to open stretch-activated Ca(2+) channels. In conclusion, mechanical stretch activates Ca(2+) influx via stretch-activated channels which are tightly regulated by the actin cytoskeleton different from other Ca(2+) influx pathways such as receptor-operated and store-operated Ca(2+) entries in HPMVECs. These results suggest that abnormal Ca(2+) homeostasis because of excessive mechanical stretch during mechanical ventilation may play a role in the progression of ALI/ARDS.
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Affiliation(s)
- Satoru Ito
- Department of Respiratory Medicine, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
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31
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Molecular mechanisms of endothelial hyperpermeability: implications in inflammation. Expert Rev Mol Med 2009; 11:e19. [PMID: 19563700 DOI: 10.1017/s1462399409001112] [Citation(s) in RCA: 281] [Impact Index Per Article: 18.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Endothelial hyperpermeability is a significant problem in vascular inflammation associated with trauma, ischaemia-reperfusion injury, sepsis, adult respiratory distress syndrome, diabetes, thrombosis and cancer. An important mechanism underlying this process is increased paracellular leakage of plasma fluid and protein. Inflammatory stimuli such as histamine, thrombin, vascular endothelial growth factor and activated neutrophils can cause dissociation of cell-cell junctions between endothelial cells as well as cytoskeleton contraction, leading to a widened intercellular space that facilitates transendothelial flux. Such structural changes initiate with agonist-receptor binding, followed by activation of intracellular signalling molecules including calcium, protein kinase C, tyrosine kinases, myosin light chain kinase, and small Rho-GTPases; these kinases and GTPases then phosphorylate or alter the conformation of different subcellular components that control cell-cell adhesion, resulting in paracellular hypermeability. Targeting key signalling molecules that mediate endothelial-junction-cytoskeleton dissociation demonstrates a therapeutic potential to improve vascular barrier function during inflammatory injury.
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Prasain N, Alexeyev M, Balczon R, Stevens T. Soluble adenylyl cyclase-dependent microtubule disassembly reveals a novel mechanism of endothelial cell retraction. Am J Physiol Lung Cell Mol Physiol 2009; 297:L73-83. [PMID: 19395666 DOI: 10.1152/ajplung.90577.2008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Soluble adenylyl cyclase toxins, such as Pseudomonas aeruginosa exoY, generate a cAMP pool that retracts cell borders. However, the cytoskeletal basis by which this cAMP signal retracts cell borders is not known. We sought to determine whether activation of chimeric, soluble adenylyl cyclase I/II (sACI/II) reorganizes either microtubules or peripheral actin. Endothelial cells were stably transfected with either green fluorescent protein-labeled alpha-tubulin or beta-actin, and then infected with adenovirus to express sACI/II. Forskolin, which stimulates both the endogenously expressed transmembrane adenylyl cyclases and sACI/II, induced cell retraction accompanied by the reorganization of peripheral microtubules. However, cortical filamentous-actin (f-actin) did not reorganize into stress fibers, and myosin light-chain-20 phosphorylation was decreased. Isoproterenol, which activates endogenous adenylyl cyclases but does not activate sACI/II, did not induce endothelial cell gaps and did not influence microtubule or f-actin architecture. Thus, sACI/II generates a cAMP signal that reorganizes microtubules and induces cell retraction, without inducing f-actin stress fibers. These findings illustrate that endothelial cell gap formation can proceed without f-actin stress fiber formation, and provide mechanistic insight how bacterial adenylyl cyclase toxins reorganize the cytoskeleton to induce cell rounding.
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Affiliation(s)
- Nutan Prasain
- Departments of Pharmacology, Center for Lung Biology, University of South Alabama, Mobile, Alabama 36688, USA
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Cioffi DL, Lowe K, Alvarez DF, Barry C, Stevens T. TRPing on the lung endothelium: calcium channels that regulate barrier function. Antioxid Redox Signal 2009; 11:765-76. [PMID: 18783312 PMCID: PMC2850299 DOI: 10.1089/ars.2008.2221] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Rises in cytosolic calcium are sufficient to initiate the retraction of endothelial cell borders and to increase macromolecular permeability. Although endothelial cell biologists have recognized the importance of shifts in cytosolic calcium for several decades, only recently have we gained a rudimentary understanding of the membrane calcium channels that change cell shape. Members of the transient receptor potential family (TRP) are chief among the molecular candidates for permeability-coupled calcium channels. Activation of calcium entry through store-operated calcium entry channels, most notably TRPC1 and TRPC4, increases lung endothelial cell permeability, as does activation of calcium entry through the TRPV4 channel. However, TRPC1 and TRPC4 channels appear to influence the lung extraalveolar endothelial barrier most prominently, whereas TRPV4 channels appear to influence the lung capillary endothelial barrier most prominently. Thus, phenotypic heterogeneity in ion channel expression and function exists within the lung endothelium, along the arterial-capillary-venous axis, and is coupled to discrete control of endothelial barrier function.
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Affiliation(s)
- Donna L Cioffi
- Center for Lung Biology, University of South Alabama, Mobile, Alabama 36688, USA
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Role of prostaglandin D2 receptor DP as a suppressor of tumor hyperpermeability and angiogenesis in vivo. Proc Natl Acad Sci U S A 2008; 105:20009-14. [PMID: 19060214 DOI: 10.1073/pnas.0805171105] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although COX-dependent production of prostaglandins (PGs) is known to be crucial for tumor angiogenesis and growth, the role of PGD(2) remains virtually unknown. Here we show that PGD(2) receptor (DP) deficiency enhances tumor progression accompanied by abnormal vascular expansion. In tumors, angiogenic endothelial cells highly express DP receptor, and its deficiency accelerates vascular leakage and angiogenesis. Administration of a synthetic DP agonist, BW245C, markedly suppresses tumor growth as well as tumor hyperpermeability in WT mice, but not in DP-deficient mice. In a corneal angiogenesis assay and a modified Miles assay, host DP deficiency potentiates angiogenesis and vascular hyperpermeability under COX-2-active situation, whereas exogenous administration of BW245C strongly inhibits both angiogenic properties in WT mice. In an in vitro assay, BW245C does not affect endothelial migration and tube formation, processes that are necessary for angiogenesis; however, it strongly improves endothelial barrier function via an increase in intracellular cAMP production. Our results identify PGD(2)/DP receptor as a new regulator of tumor vascular permeability, indicating DP agonism may be exploited as a potential therapy for the treatment of cancer.
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35
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36
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Do TQ, Moshkani S, Castillo P, Anunta S, Pogosyan A, Cheung A, Marbois B, Faull KF, Ernst W, Chiang SM, Fujii G, Clarke CF, Foster K, Porter E. Lipids including cholesteryl linoleate and cholesteryl arachidonate contribute to the inherent antibacterial activity of human nasal fluid. THE JOURNAL OF IMMUNOLOGY 2008; 181:4177-87. [PMID: 18768875 DOI: 10.4049/jimmunol.181.6.4177] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Mucosal surfaces provide first-line defense against microbial invasion through their complex secretions. The antimicrobial activities of proteins in these secretions have been well delineated, but the contributions of lipids to mucosal defense have not been defined. We found that normal human nasal fluid contains all major lipid classes (in micrograms per milliliter), as well as lipoproteins and apolipoprotein A-I. The predominant less polar lipids were myristic, palmitic, palmitoleic, stearic, oleic, and linoleic acid, cholesterol, and cholesteryl palmitate, cholesteryl linoleate, and cholesteryl arachidonate. Normal human bronchioepithelial cell secretions exhibited a similar lipid composition. Removal of less-polar lipids significantly decreased the inherent antibacterial activity of nasal fluid against Pseudomonas aeruginosa, which was in part restored after replenishing the lipids. Furthermore, lipids extracted from nasal fluid exerted direct antibacterial activity in synergism with the antimicrobial human neutrophil peptide HNP-2 and liposomal formulations of cholesteryl linoleate and cholesteryl arachidonate were active against P. aeruginosa at physiological concentrations as found in nasal fluid and exerted inhibitory activity against other Gram-negative and Gram-positive bacteria. These data suggest that host-derived lipids contribute to mucosal defense. The emerging concept of host-derived antimicrobial lipids unveils novel roads to a better understanding of the immunology of infectious diseases.
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Affiliation(s)
- Thai Q Do
- Department of Biological Sciences, California State University, Los Angeles, CA 90032, USA
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Inhaled milrinone attenuates experimental acute lung injury. Intensive Care Med 2008; 35:171-8. [PMID: 18972099 DOI: 10.1007/s00134-008-1344-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Accepted: 10/11/2008] [Indexed: 12/14/2022]
Abstract
PURPOSE To test whether inhalation of the phosphodiesterase 3 inhibitor milrinone may attenuate experimental acute lung injury (ALI). METHODS In rats, ALI was induced by infusion of oleic acid (OA). After 30 min, milrinone was inhaled either as single dose, or repeatedly in 30 min intervals. In mice, ALI was induced by intratracheal instillation of hydrochloric acid, followed by a single milrinone inhalation. RESULTS Four hours after OA infusion, ALI was evident as lung inflammation, protein-rich edema and hypoxemia. A single inhalation of milrinone attenuated the increase in lung wet-to-dry weight ratio and myeloperoxidase activity, and reduced protein concentration, neutrophil counts and TNF-alpha levels in bronchoalveolar lavage. This effect was further pronounced when milrinone was repeatedly inhaled. In mice with acid-induced ALI, milrinone attenuated hypoxemia and prevented the increase in lung myeloperoxidase activity. CONCLUSIONS Inhalation of aerosolized milrinone may present a novel therapeutic strategy for the treatment of ALI.
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38
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Prasain N, Stevens T. The actin cytoskeleton in endothelial cell phenotypes. Microvasc Res 2008; 77:53-63. [PMID: 19028505 DOI: 10.1016/j.mvr.2008.09.012] [Citation(s) in RCA: 208] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Accepted: 09/26/2008] [Indexed: 10/21/2022]
Abstract
Endothelium forms a semi-permeable barrier that separates blood from the underlying tissue. Barrier function is largely determined by cell-cell and cell-matrix adhesions that define the limits of cell borders. Yet, such cell-cell and cell-matrix tethering is critically reliant upon the nature of adherence within the cell itself. Indeed, the actin cytoskeleton fulfills this essential function, to provide a strong, dynamic intracellular scaffold that organizes integral membrane proteins with the cell's interior, and responds to environmental cues to orchestrate appropriate cell shape. The actin cytoskeleton is comprised of three distinct, but inter-related structures, including actin cross-linking of spectrin within the membrane skeleton, the cortical actin rim, and actomyosin-based stress fibers. This review addresses each of these actin-based structures, and discusses cellular signals that control the disposition of actin in different endothelial cell phenotypes.
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Affiliation(s)
- Nutan Prasain
- Department of Molecular and Cellular Pharmacology, College of Medicine, University of South Alabama, Mobile, AL 36688, USA
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Dodd-o JM, Hristopoulos ML, Kibler K, Gutkowska J, Mukaddam-Daher S, Gonzalez A, Welsh-Servinsky LE, Pearse DB. The role of natriuretic peptide receptor-A signaling in unilateral lung ischemia-reperfusion injury in the intact mouse. Am J Physiol Lung Cell Mol Physiol 2008; 294:L714-23. [PMID: 18223163 DOI: 10.1152/ajplung.00185.2007] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ischemia-reperfusion (IR) causes human lung injury in association with the release of atrial and brain natriuretic peptides (ANP and BNP), but the role of ANP/BNP in IR lung injury is unknown. ANP and BNP bind to natriuretic peptide receptor-A (NPR-A) generating cGMP and to NPR-C, a clearance receptor that can decrease intracellular cAMP. To determine the role of NPR-A signaling in IR lung injury, we administered the NPR-A blocker anantin in an in vivo SWR mouse preparation of unilateral lung IR. With uninterrupted ventilation, the left pulmonary artery was occluded for 30 min and then reperfused for 60 or 150 min. Anantin administration decreased IR-induced Evans blue dye extravasation and wet weight in the reperfused left lung, suggesting an injurious role for NPR-A signaling in lung IR. In isolated mouse lungs, exogenous ANP (2.5 nM) added to the perfusate significantly increased the filtration coefficient sevenfold only if lungs were subjected to IR. This effect of ANP was also blocked by anantin. Unilateral in vivo IR increased endogenous plasma ANP, lung cGMP concentration, and lung protein kinase G (PKG(I)) activation. Anantin enhanced plasma ANP concentrations and attenuated the increase in cGMP and PKG(I) activation but had no effect on lung cAMP. These data suggest that lung IR triggered ANP release and altered endothelial signaling so that NPR-A activation caused increased pulmonary endothelial permeability.
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Affiliation(s)
- Jeffrey M Dodd-o
- Department of Anesthesia and Critical Care, School of Medicine, The Johns Hopkins Medical Institutions, Baltimore, MD 21287-9106, USA.
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Abstract
Extracellular adenosine has been implicated in adaptation to hypoxia and previous studies demonstrated a central role in vascular responses. Here, we examined the contribution of individual adenosine receptors (ARs: A1AR/A2AAR/A2BAR/A3AR) to vascular leak induced by hypoxia. Initial profiling studies revealed that siRNA-mediated repression of the A2BAR selectively increased endothelial leak in response to hypoxia in vitro. In parallel, vascular permeability was significantly increased in vascular organs of A2BAR(-/-)-mice subjected to ambient hypoxia (8% oxygen, 4 hours; eg, lung: 2.1 +/- 0.12-fold increase). By contrast, hypoxia-induced vascular leak was not accentuated in A1AR(-/-)-, A2AAR(-/-)-, or A3AR(-/-)-deficient mice, suggesting a degree of specificity for the A2BAR. Further studies in wild type mice revealed that the selective A2BAR antagonist PSB1115 resulted in profound increases in hypoxia-associated vascular leakage while A2BAR agonist (BAY60-6583 [2-[6-amino-3,5-dicyano-4-[4-(cyclopropylmethoxy)-. phenyl]pyridin-2-ylsulfanyl]acetamide]) treatment was associated with almost complete reversal of hypoxia-induced vascular leakage (eg, lung: 2.0 +/- 0.21-fold reduction). Studies in bone marrow chimeric A2BAR mice suggested a predominant role of vascular A2BARs in this response, while hypoxia-associated increases in tissue neutrophils were, at least in part, mediated by A2BAR expressing hematopoietic cells. Taken together, these studies provide pharmacologic and genetic evidence for vascular A2BAR signaling as central control point of hypoxia-associated vascular leak.
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Grootendorst DC, Gauw SA, Verhoosel RM, Sterk PJ, Hospers JJ, Bredenbröker D, Bethke TD, Hiemstra PS, Rabe KF. Reduction in sputum neutrophil and eosinophil numbers by the PDE4 inhibitor roflumilast in patients with COPD. Thorax 2007; 62:1081-7. [PMID: 17573446 PMCID: PMC2094292 DOI: 10.1136/thx.2006.075937] [Citation(s) in RCA: 218] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2006] [Accepted: 05/16/2007] [Indexed: 11/04/2022]
Abstract
BACKGROUND Roflumilast is a targeted oral once-daily administered phosphodiesterase 4 (PDE4) inhibitor with clinical efficacy in chronic obstructive pulmonary disease (COPD). Results from in vitro studies with roflumilast indicate that it has anti-inflammatory properties that may be applicable for the treatment of COPD. METHODS In a crossover study, 38 patients with COPD (mean (SD) age 63.1 (7.0) years, post-bronchodilator forced expiratory volume in 1 s (FEV(1)) 61.0 (12.6)% predicted) received 500 microg roflumilast or placebo once daily for 4 weeks. Induced sputum samples were collected before and after 2 and 4 weeks of treatment. Differential and absolute cell counts were determined in whole sputum samples. Markers of inflammation were determined in sputum supernatants and blood. Spirometry was performed weekly. RESULTS Roflumilast significantly reduced the absolute number of neutrophils and eosinophils/g sputum compared with placebo by 35.5% (95% CI 15.6% to 50.7%; p = 0.002) and 50.0% (95% CI 26.8% to 65.8%; p<0.001), respectively. The relative proportion of sputum neutrophils and eosinophils was not affected by treatment (p>0.05). Levels of soluble interleukin-8, neutrophil elastase, eosinophil cationic protein and alpha(2)-macroglobulin in sputum and the release of tumour necrosis factor alpha from blood cells were significantly reduced by roflumilast compared with placebo treatment (p<0.05 for all). Post-bronchodilator FEV(1) improved significantly during roflumilast compared with placebo treatment with a mean difference between treatments of 68.7 ml (95% CI 12.9 to 124.5; p = 0.018). CONCLUSION PDE4 inhibition by roflumilast treatment for 4 weeks reduced the number of neutrophils and eosinophils, as well as soluble markers of neutrophilic and eosinophilic inflammatory activity in induced sputum samples of patients with COPD. This anti-inflammatory effect may in part explain the concomitant improvement in post-bronchodilator FEV(1).
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Affiliation(s)
- Diana C Grootendorst
- Department of Pulmonology, Leiden University Medical Center, Leiden, The Netherlands.
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Hecquet CM, Ahmmed GU, Vogel SM, Malik AB. Role of TRPM2 channel in mediating H2O2-induced Ca2+ entry and endothelial hyperpermeability. Circ Res 2007; 102:347-55. [PMID: 18048770 DOI: 10.1161/circresaha.107.160176] [Citation(s) in RCA: 176] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Oxidative stress through the production of oxygen metabolites such as hydrogen peroxide (H2O2) increases vascular endothelial permeability. H2O2 stimulates ADP-ribose formation, which in turn opens transient receptor potential melastatin (TRPM)2 channels. Here, in endothelial cells, we demonstrate transcript and protein expression of TRPM2, a Ca2+-permeable, nonselective cation channel. We further show the importance of TRPM2 expression in signaling of increased endothelial permeability by oxidative stress. Exposure of endothelial cell monolayers to sublytic concentrations of H2O2 induced a cationic current measured by patch-clamp recording and Ca2+ entry detected by intracellular fura-2 fluorescence. H2O2 in a concentration-dependent manner also decreased trans-monolayer transendothelial electrical resistance for 3 hours (with maximal effect seen at 300 micromol/L H2O2), indicating opening of interendothelial junctions. The cationic current, Ca2+ entry, and transendothelial electrical resistance decrease elicited by H2O2 were inhibited by siRNA depleting TRPM2 or antibody blocking of TRPM2. H2O2 responses were attenuated by overexpression of the dominant-negative splice variant of TRPM2 or inhibition of ADP-ribose formation. Overexpression of the full-length TRPM2 enhanced H2O2-mediated Ca2+ entry, cationic current, and the transendothelial electrical resistance decrease. Thus, TRPM2 mediates H2O2-induced increase in endothelial permeability through the activation of Ca2+ entry via TRPM2. TRPM2 represents a novel therapeutic target directed against oxidant-induced endothelial barrier disruption.
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Affiliation(s)
- Claudie M Hecquet
- Department of Pharmacology and Center for Lung and Vascular Biology, University of Illinois College of Medicine, Chicago, IL 60612, USA
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Heterogeneity of barrier function in the lung reflects diversity in endothelial cell junctions. Microvasc Res 2007; 75:391-402. [PMID: 18068735 DOI: 10.1016/j.mvr.2007.10.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Accepted: 10/19/2007] [Indexed: 12/31/2022]
Abstract
Endothelial cells assemble unique barriers that confer specific permeability requirements at different vascular segments. We examined lung microvascular and artery endothelial cells to gain insight into mechanisms for segment-specific barrier functions. Transendothelial electrical resistance was significantly higher in microvascular barriers, and a 50% reduction in barrier function required 5-fold higher concentration of cytochalasin D in the microvascular compared to the arterial barrier. Transcriptional profiling studies identified N-cadherin and activated leukocyte cell adhesion molecule (ALCAM) to be most highly expressed in microvascular than in pulmonary artery endothelial cells. ALCAM was detected in microvascular endothelial cells in the alveolar septum but not in endothelial cells in larger pulmonary vessels in situ. This pattern was retained in culture as ALCAM was recruited to cell junctions in pulmonary microvascular endothelial cells but remained predominantly cytosolic in pulmonary artery endothelial cells. Confocal analysis revealed ALCAM in the lateral plasma membrane domain where it co-localized with N- and VE-cadherin. This finding was supported by co-immunoprecipitation studies demonstrating the presence of ALCAM in multiple adherens junction protein complexes. These functional, biophysical and molecular findings suggest specialization of the adherens junction as a basis for a highly restrictive endothelial barrier to control fluid flux into the alveolar airspace.
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Alvarez DF, King JA, Weber D, Addison E, Liedtke W, Townsley MI. Transient receptor potential vanilloid 4-mediated disruption of the alveolar septal barrier: a novel mechanism of acute lung injury. Circ Res 2006; 99:988-95. [PMID: 17008604 PMCID: PMC2562953 DOI: 10.1161/01.res.0000247065.11756.19] [Citation(s) in RCA: 229] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Disruption of the alveolar septal barrier leads to acute lung injury, patchy alveolar flooding, and hypoxemia. Although calcium entry into endothelial cells is critical for loss of barrier integrity, the cation channels involved in this process have not been identified. We hypothesized that activation of the vanilloid transient receptor potential channel TRPV4 disrupts the alveolar septal barrier. Expression of TRPV4 was confirmed via immunohistochemistry in the alveolar septal wall in human, rat, and mouse lung. In isolated rat lung, the TRPV4 activators 4alpha-phorbol-12,13-didecanoate and 5,6- or 14,15-epoxyeicosatrienoic acid, as well as thapsigargin, a known activator of calcium entry via store-operated channels, all increased lung endothelial permeability as assessed by measurement of the filtration coefficient, in a dose- and calcium-entry dependent manner. The TRPV antagonist ruthenium red blocked the permeability response to the TRPV4 agonists, but not to thapsigargin. Light and electron microscopy of rat and mouse lung revealed that TRPV4 agonists preferentially produced blebs or breaks in the endothelial and epithelial layers of the alveolar septal wall, whereas thapsigargin disrupted interendothelial junctions in extraalveolar vessels. The permeability response to 4alpha-phorbol-12,13-didecanoate was absent in TRPV4(-/-) mice, whereas the response to thapsigargin remained unchanged. Collectively, these findings implicate TRPV4 in disruption of the alveolar septal barrier and suggest its participation in the pathogenesis of acute lung injury.
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Affiliation(s)
- Diego F. Alvarez
- Department of Physiology, University of South Alabama
- Center for Lung Biology, University of South Alabama
| | - Judy A. King
- Department of Pharmacology and Pathology, University of South Alabama
- Center for Lung Biology, University of South Alabama
| | - David Weber
- Department of Physiology, University of South Alabama
| | - Emile Addison
- Department of Physiology, University of South Alabama
| | - Wolfgang Liedtke
- Departments of Medicine/Neurology and Neurobiology, Duke University
| | - Mary I. Townsley
- Department of Physiology, University of South Alabama
- Center for Lung Biology, University of South Alabama
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Sacks RS, Remillard CV, Agange N, Auger WR, Thistlethwaite PA, Yuan JXJ. Molecular Biology of Chronic Thromboembolic Pulmonary Hypertension. Semin Thorac Cardiovasc Surg 2006; 18:265-76. [PMID: 17185190 DOI: 10.1053/j.semtcvs.2006.09.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2006] [Indexed: 01/17/2023]
Abstract
Recent efforts have seen major advances in elucidating the mechanisms underlying pulmonary arterial hypertension. However, chronic thromboembolic pulmonary hypertension (CTEPH) often has been excluded from these studies. Consequently, whereas the clinical, radiographic, and hemodynamic characteristics of CTEPH have been well described, there remains a deficit in our understanding of the cellular, molecular, and genetic mechanisms underlying CTEPH. Furthermore, although prior venous thromboembolism may act as the inciting event, it is still unclear what predisposes some patients to develop CTEPH. CTEPH has two major pathogenic components. The first is the primary obstruction of central pulmonary arteries by accumulation of thrombotic material. The second is characterized by severe pulmonary vascular remodeling, similar to that seen in idiopathic pulmonary arterial hypertension. Other articles in this series describe the pathological, surgical, and therapeutic aspects of CTEPH. Here, we review the potential molecular and cellular mechanisms that may contribute to the pathogenesis of CTEPH.
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Affiliation(s)
- Richard S Sacks
- Department of Medicine, University of California, San Diego, La Jolla 92093-0725, USA
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Wang Y, Maciejewski BS, Lee N, Silbert O, McKnight NL, Frangos JA, Sanchez-Esteban J. Strain-induced fetal type II epithelial cell differentiation is mediated via cAMP-PKA-dependent signaling pathway. Am J Physiol Lung Cell Mol Physiol 2006; 291:L820-7. [PMID: 16751225 DOI: 10.1152/ajplung.00068.2006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The signaling pathways by which mechanical forces modulate fetal lung development remain largely unknown. In the present study, we tested the hypothesis that strain-induced fetal type II cell differentiation is mediated via the cAMP signaling pathway. Freshly isolated E19 fetal type II epithelial cells were cultured on collagen-coated silastic membranes and exposed to mechanical strain for varying intervals, to simulate mechanical forces during lung development. Unstretched samples were used as controls. Mechanical strain activated heterotrimeric G-protein alpha(s) subunit, cAMP, and the transcription factor cAMP response element binding protein (CREB). Incubation of E19 cells with the PKA inhibitor H-89 significantly decreased strain-induced CREB phosphorylation. Moreover, adenylate cyclase 5 and CREB genes were also mechanically induced. In contrast, components of the PKA-independent (Epac) pathway, including Rap-1 or B-Raf, were not phosphorylated by strain. The addition of forskolin or dibutyryl cAMP to unstretched E19 monolayers markedly upregulated expression of the type II cell differentiation marker surfactant protein C, whereas the Epac agonist 8-pCPT-2'-O-Me-cAMP had no effect. Furthermore, incubation of E19 cells with the PKA inhibitor Rp-2'-O-monobutyryladenosine 3',5'-cyclic monophosphorothioate or transient transfection with plasmid DNA containing a PKA inhibitor expression vector significantly decreased strain-induced surfactant protein C mRNA expression. In conclusion, these studies indicate that the cAMP-PKA-dependent signaling pathway is activated by force in fetal type II cells and participates in strain-induced fetal type II cell differentiation.
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Affiliation(s)
- Yulian Wang
- Department of Pediatrics, Women & Infants Hospital of Rhode Island, Brown Medical School, 101 Dudley St., Providence, RI 02905, USA
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Sayner SL, Alexeyev M, Dessauer CW, Stevens T. Soluble adenylyl cyclase reveals the significance of cAMP compartmentation on pulmonary microvascular endothelial cell barrier. Circ Res 2006; 98:675-81. [PMID: 16469954 DOI: 10.1161/01.res.0000209516.84815.3e] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Subtle elevations in cAMP localized to the plasma membrane intensely strengthen endothelial barrier function. Paradoxically, pathogenic bacteria insert adenylyl cyclases (ACs) into eukaryotic cells generating a time-dependent cytosolic cAMP-increase that disrupts rather than strengthens the endothelial barrier. These findings bring into question whether membrane versus cytosolic AC activity dominates in control of cell adhesion. To address this problem, a mammalian forskolin-sensitive soluble AC (sACI/II) was expressed in pulmonary microvascular endothelial cells. Forskolin stimulated this sACI/II construct generating a small cytosolic cAMP-pool that was not regulated by phosphodiesterases or Galphas. Whereas forskolin simultaneously activated the sACI/II construct and endogenous transmembrane ACs, the modest sACI/II activity overwhelmed the barrier protective effects of plasma membrane activity to induce endothelial gap formation. Retargeting sACI/II to the plasma membrane retained AC activity but protected the endothelial cell barrier. These findings demonstrate for the first time that the intracellular location of cAMP synthesis critically determines its physiological outcome.
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Affiliation(s)
- Sarah L Sayner
- Center for Lung Biology, Department of Pharmacology, University of South Alabama, College of Medicine, Mobile, AL 36688, USA
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Tiruppathi C, Ahmmed GU, Vogel SM, Malik AB. Ca2+Signaling, TRP Channels, and Endothelial Permeability. Microcirculation 2006; 13:693-708. [PMID: 17085428 DOI: 10.1080/10739680600930347] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Increased endothelial permeability is the hallmark of inflammatory vascular edema. Inflammatory mediators that bind to heptahelical G protein-coupled receptors trigger increased endothelial permeability by increasing the intracellular Ca2+ concentration ([Ca2+]i). The rise in [Ca2+]i activates key signaling pathways that mediate cytoskeletal reorganization (through myosin-light-chain-dependent contraction) and the disassembly of VE-cadherin at the adherens junctions. The Ca2+-dependent protein kinase C (PKC) isoform PKCalpha plays a crucial role in initiating endothelial cell contraction and disassembly of VE-cadherin junctions. The increase in [Ca2+]i induced by inflammatory agonists such as thrombin and histamine is achieved by the generation of inositol 1,4,5-trisphosphate (IP3), activation of IP3-receptors, release of stored intracellular Ca2+, and Ca2+ entry through plasma membrane channels. IP3-sensitive Ca2+-store depletion activates plasma membrane cation channels (i.e., store-operated cation channels [SOCs] or Ca2+ release-activated channels [CRACs]) to cause Ca2+ influx into endothelial cells. Recent studies have identified members of Drosophila transient receptor potential (TRP) gene family of channels that encode functional SOCs in endothelial cells. These studies also suggest that the canonical TRPC homologue TRPC1 is the predominant isoform expressed in human vascular endothelial cells, and is the essential component of the SOC in this cell type. Further, evidence suggests that the inflammatory cytokine tumor necrosis factor-alpha can induce the expression of TRPC1 in human vascular endothelial cells signaling via the nuclear factor-kappaB pathway. Increased expression of TRPC1 augments Ca2+ influx via SOCs and potentiates the thrombin-induced increase in permeability in human vascular endothelial cells. Deletion of the canonical TRPC homologue in mouse, TRPC4, caused impairment in store-operated Ca2+ current and Ca2+-store release-activated Ca2+ influx in aortic and lung endothelial cells. In TRPC4 knockout (TRPC4-/-) mice, acetylcholine-induced endothelium-dependent smooth muscle relaxation was drastically reduced. In addition, TRPC4-/- mouse-lung endothelial cells exhibited lack of actin-stress fiber formation and cell retraction in response to thrombin activation of protease-activated receptor-1 (PAR-1) in endothelial cells. The increase in lung microvascular permeability in response to PAR-1 activation was inhibited in TRPC4-/- mice. These results indicate that endothelial TRP channels such as TRPC1 and TRPC4 play an important role in signaling agonist-induced increases in endothelial permeability.
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Affiliation(s)
- Chinnaswamy Tiruppathi
- Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612, USA.
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Abstract
The microvascular endothelial cell monolayer localized at the critical interface between the blood and vessel wall has the vital functions of regulating tissue fluid balance and supplying the essential nutrients needed for the survival of the organism. The endothelial cell is an exquisite “sensor” that responds to diverse signals generated in the blood, subendothelium, and interacting cells. The endothelial cell is able to dynamically regulate its paracellular and transcellular pathways for transport of plasma proteins, solutes, and liquid. The semipermeable characteristic of the endothelium (which distinguishes it from the epithelium) is crucial for establishing the transendothelial protein gradient (the colloid osmotic gradient) required for tissue fluid homeostasis. Interendothelial junctions comprise a complex array of proteins in series with the extracellular matrix constituents and serve to limit the transport of albumin and other plasma proteins by the paracellular pathway. This pathway is highly regulated by the activation of specific extrinsic and intrinsic signaling pathways. Recent evidence has also highlighted the importance of the heretofore enigmatic transcellular pathway in mediating albumin transport via transcytosis. Caveolae, the vesicular carriers filled with receptor-bound and unbound free solutes, have been shown to shuttle between the vascular and extravascular spaces depositing their contents outside the cell. This review summarizes and analyzes the recent data from genetic, physiological, cellular, and morphological studies that have addressed the signaling mechanisms involved in the regulation of both the paracellular and transcellular transport pathways.
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Affiliation(s)
- Dolly Mehta
- Center of Lung and Vascular Biology, Dept. of Pharmacology (M/C 868), University of Illinois, 835 S. Wolcott Avenue, Chicago, IL 60612, USA
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