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Tozzi M, Hansen JB, Novak I. Pannexin-1 mediated ATP release in adipocytes is sensitive to glucose and insulin and modulates lipolysis and macrophage migration. Acta Physiol (Oxf) 2020; 228:e13360. [PMID: 31400255 DOI: 10.1111/apha.13360] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 07/29/2019] [Accepted: 08/07/2019] [Indexed: 12/15/2022]
Abstract
AIM Extracellular ATP signalling is involved in many physiological and pathophysiological processes in several tissues, including adipose tissue. Adipocytes have crucial functions in lipid and glucose metabolism and they express purinergic receptors. However, the sources of extracellular ATP in adipose tissue are not well characterized. In the present study, we investigated the mechanism and regulation of ATP release in white adipocytes, and evaluated the role of extracellular ATP as potential autocrine and paracrine signal. METHODS Online ATP release was monitored in C3H10T1/2 cells and freshly isolated murine adipocytes. The ATP release mechanism and its regulation were tested in cells exposed to adrenergic agonists, insulin, glucose load and pharmacological inhibitors. Cell metabolism was monitored using Seahorse respirometry and expression analysis of pannexin-1 was performed on pre- and mature adipocytes. The ATP signalling was evaluated in live cell imaging (Ca2+ , pore formation), glycerol release and its effect on macrophages was tested in co-culture and migration assays. RESULTS Here, we show that upon adrenergic stimulation white murine adipocytes release ATP through the pannexin-1 pore that is regulated by a cAMP-PKA-dependent pathway. The ATP release correlates with increased cell metabolism and is sensitive to glucose. Extracellular ATP induces Ca2+ signalling and lipolysis in adipocytes and promotes macrophage migration. Importantly, ATP release is markedly inhibited by insulin, which operates via the activation of phosphodiesterase 3. CONCLUSIONS Our findings reveal an insulin-pannexin-1-purinergic signalling crosstalk in adipose tissue and we propose that deregulation of this signalling may contribute to adipose tissue inflammation and type 2 diabetes.
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Affiliation(s)
- Marco Tozzi
- Section for Cell Biology and Physiology, Department of Biology University of Copenhagen Copenhagen Denmark
| | - Jacob B. Hansen
- Section for Cell Biology and Physiology, Department of Biology University of Copenhagen Copenhagen Denmark
| | - Ivana Novak
- Section for Cell Biology and Physiology, Department of Biology University of Copenhagen Copenhagen Denmark
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52
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A Genetic Polymorphism in the Pannexin1 Gene Predisposes for The Development of Endothelial Dysfunction with Increasing BMI. Biomolecules 2020; 10:biom10020208. [PMID: 32023876 PMCID: PMC7072696 DOI: 10.3390/biom10020208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/16/2020] [Accepted: 01/26/2020] [Indexed: 01/07/2023] Open
Abstract
Endothelial dysfunction worsens when body mass index (BMI) increases. Pannexin1 (Panx1) ATP release channels regulate endothelial function and lipid homeostasis in mice. We investigated whether the Panx1-400A>C single nucleotide polymorphism (SNP), encoding for a gain-of-function channel, associates with endothelial dysfunction in non-obese and obese individuals. Myocardial blood flow (MBF) was measured by 13N-ammonia positron emission/computed tomography at rest, during cold pressor test (CPT) or dipyridamole-induced hyperemia. Myocardial flow reserve (MFR) and endothelial function were compared in 43 non-obese (BMI < 30 kg/m2) vs. 29 obese (BMI 30 kg/m2) participants and genotyping for the Panx1-400A>C SNP was performed. Groups comprised subjects homozygous for the C allele (n = 40) vs. subjects with at least one A allele (n = 32). MBF (during CPT or hyperemia), MFR and endothelial function correlated negatively with BMI in the full cohort. BMI correlated negatively with MFR and endothelial function in non-obese Panx1-400C subjects, but not in Panx1-400A individuals nor in obese groups. BMI correlated positively with serum triglycerides, insulin or HOMA. MFR correlated negatively with these factors in non-obese Panx1-400C but not in Panx1-400A individuals. Here, we demonstrated that Panx1-400C SNP predisposes to BMI-dependent endothelial dysfunction in non-obese subjects. This effect may be masked by excessive dysregulation of metabolic factors in obese individuals.
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Nielsen BS, Toft-Bertelsen TL, Lolansen SD, Anderson CL, Nielsen MS, Thompson RJ, MacAulay N. Pannexin 1 activation and inhibition is permeant-selective. J Physiol 2020; 598:361-379. [PMID: 31698505 DOI: 10.1113/jp278759] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 11/05/2019] [Indexed: 01/14/2023] Open
Abstract
KEY POINTS The large-pore channel pannexin 1 (Panx1) is expressed in many cell types and can open upon different, yet not fully established, stimuli. Panx1 permeability is often inferred from channel permeability to fluorescent dyes, but it is currently unknown whether dye permeability translates to permeability to other molecules. Cell shrinkage and C-terminal cleavage led to a Panx1 open-state with increased permeability to atomic ions (current), but did not alter ethidium uptake. Panx1 inhibitors affected Panx1-mediated ion conduction differently from ethidium permeability, and inhibitor efficiency towards a given molecule therefore cannot be extrapolated to its effects on the permeability of another. We conclude that ethidium permeability does not reflect equal permeation of other molecules and thus is no measure of general Panx1 activity. ABSTRACT Pannexin 1 (Panx1) is a large-pore membrane channel connecting the extracellular milieu with the cell interior. While several activation regimes activate Panx1 in a variety of cell types, the selective permeability of an open Panx1 channel remains unresolved: does a given activation paradigm increase Panx1's permeability towards all permeants equally and does fluorescent dye flux serve as a proxy for biological permeation through an open channel? To explore permeant-selectivity of Panx1 activation and inhibition, we employed Panx1-expressing Xenopus laevis oocytes and HEK293T cells. We report that different mechanisms of activation of Panx1 differentially affected ethidium and atomic ion permeation. Most notably, C-terminal truncation or cell shrinkage elevated Panx1-mediated ion conductance, but had no effect on ethidium permeability. In contrast, extracellular pH changes predominantly affected ethidium permeability but not ionic conductance. High [K+ ]o did not increase the flux of either of the two permeants. Once open, Panx1 demonstrated preference for anionic permeants, such as Cl- , lactate and glutamate, while not supporting osmotic water flow. Panx1 inhibitors displayed enhanced potency towards Panx1-mediated currents compared to that of ethidium uptake. We conclude that activation or inhibition of Panx1 display permeant-selectivity and that permeation of ethidium does not necessarily reflect an equal permeation of smaller biological molecules and atomic ions.
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Affiliation(s)
- Brian Skriver Nielsen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Trine Lisberg Toft-Bertelsen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara Diana Lolansen
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Connor L Anderson
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Morten Schak Nielsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Roger J Thompson
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada.,Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Nanna MacAulay
- Department of Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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54
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Molica F, Meens MJ, Pelli G, Hautefort A, Emre Y, Imhof BA, Fontana P, Scemes E, Morel S, Kwak BR. Selective inhibition of Panx1 channels decreases hemostasis and thrombosis in vivo. Thromb Res 2019; 183:56-62. [PMID: 31669824 DOI: 10.1016/j.thromres.2019.09.028] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 08/30/2019] [Accepted: 09/16/2019] [Indexed: 01/01/2023]
Abstract
BACKGROUND Hemostasis is a tightly regulated physiological process to rapidly induce hemostatic plugs at sites of vascular injury. Inappropriate activation of this process may lead to thrombosis, i.e. pathological blood clot formation in uninjured vessels or on atherosclerotic lesions. ATP release through Pannexin1 (Panx1) membrane channels contributes to collagen-induced platelet aggregation in vitro. OBJECTIVE To investigate the effects of genetic and pharmacological inhibition of Panx1 on hemostasis and thrombosis in vivo. RESULTS Bleeding time after tail clipping was increased by 2.5-fold in Panx1-/- mice compared to wild-type controls, suggesting that Panx1 deficiency impairs primary hemostasis. Wire myography on mesenteric arteries revealed diminished vasoconstriction in response to phenylephrine or U446619 in Panx1-/- mice. Mice with platelet-specific deletion of Panx1 (Panx1PDel) displayed 2-fold longer tail bleeding times than Panx1fl/fl controls. Moreover, venous thromboembolism (VTE) after injection of collagen/epinephrine in the jugular vein was reduced in Panx1-/- and Panx1PDel mice. Panx1PDel mice also showed reduced FeCl3-induced thrombosis in mesenteric arteries. BrilliantBlue-FCF, a Panx1 channel inhibitor, decreased collagen-induced platelet aggregation in vitro, increased tail bleeding time and reduced VTE in wild-type mice. Furthermore, we developed a specific Panx1 blocking antibody targeting a Panx1 extracellular loop, which reduced ATP release from platelets in vitro. Treating wild-type mice with this antibody increased tail bleeding time and decreased VTE compared to control antibody. CONCLUSIONS Panx1 channel deletion or inhibition diminishes clot formation during hemostasis and thrombosis in vivo. Blocking Panx1 channels may be an attractive strategy for modulating platelet aggregation in thrombotic disease.
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Affiliation(s)
- Filippo Molica
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Merlijn J Meens
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Graziano Pelli
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Aurélie Hautefort
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Yalin Emre
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Beat A Imhof
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Pierre Fontana
- Division of Angiology and Haemostasis, Geneva University Hospitals and Geneva Platelet Group, University of Geneva, Geneva, Switzerland
| | - Eliana Scemes
- Dept of Cell Biology and Anatomy, New York Medical College, Valhalla, NY, USA
| | - Sandrine Morel
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland
| | - Brenda R Kwak
- Dept of Pathology and Immunology, University of Geneva, Geneva, Switzerland; Dept of Medical Specializations - Cardiology, University of Geneva, Geneva, Switzerland.
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Living on the Edge: Efferocytosis at the Interface of Homeostasis and Pathology. Immunity 2019; 50:1149-1162. [PMID: 31117011 DOI: 10.1016/j.immuni.2019.04.018] [Citation(s) in RCA: 223] [Impact Index Per Article: 44.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Revised: 04/13/2019] [Accepted: 04/29/2019] [Indexed: 01/23/2023]
Abstract
Nearly every tissue in the body undergoes routine turnover of cells as part of normal healthy living. The majority of these cells undergoing turnover die via apoptosis, and then are rapidly removed by phagocytes by the process of efferocytosis that is anti-inflammatory. However, a number of pathologies have recently been linked to defective clearance of apoptotic cells. Perturbed clearance arises for many reasons, including overwhelming of the clearance machinery, disruptions at different stages of efferocytosis, and responses of phagocytes during efferocytosis, all of which can alter the homeostatic tissue environment. This review covers linkages of molecules involved in the different phases of efferocytosis to disease pathologies that can arise due to their loss or altered function.
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56
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Vallon V, Unwin R, Inscho EW, Leipziger J, Kishore BK. Extracellular Nucleotides and P2 Receptors in Renal Function. Physiol Rev 2019; 100:211-269. [PMID: 31437091 DOI: 10.1152/physrev.00038.2018] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The understanding of the nucleotide/P2 receptor system in the regulation of renal hemodynamics and transport function has grown exponentially over the last 20 yr. This review attempts to integrate the available data while also identifying areas of missing information. First, the determinants of nucleotide concentrations in the interstitial and tubular fluids of the kidney are described, including mechanisms of cellular release of nucleotides and their extracellular breakdown. Then the renal cell membrane expression of P2X and P2Y receptors is discussed in the context of their effects on renal vascular and tubular functions. Attention is paid to effects on the cortical vasculature and intraglomerular structures, autoregulation of renal blood flow, tubuloglomerular feedback, and the control of medullary blood flow. The role of the nucleotide/P2 receptor system in the autocrine/paracrine regulation of sodium and fluid transport in the tubular and collecting duct system is outlined together with its role in integrative sodium and fluid homeostasis and blood pressure control. The final section summarizes the rapidly growing evidence indicating a prominent role of the extracellular nucleotide/P2 receptor system in the pathophysiology of the kidney and aims to identify potential therapeutic opportunities, including hypertension, lithium-induced nephropathy, polycystic kidney disease, and kidney inflammation. We are only beginning to unravel the distinct physiological and pathophysiological influences of the extracellular nucleotide/P2 receptor system and the associated therapeutic perspectives.
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Affiliation(s)
- Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Robert Unwin
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Edward W Inscho
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Jens Leipziger
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Bellamkonda K Kishore
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
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57
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Brown IAM, Diederich L, Good ME, DeLalio LJ, Murphy SA, Cortese-Krott MM, Hall JL, Le TH, Isakson BE. Vascular Smooth Muscle Remodeling in Conductive and Resistance Arteries in Hypertension. Arterioscler Thromb Vasc Biol 2019; 38:1969-1985. [PMID: 30354262 DOI: 10.1161/atvbaha.118.311229] [Citation(s) in RCA: 147] [Impact Index Per Article: 29.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Cardiovascular disease is a leading cause of death worldwide and accounts for >17.3 million deaths per year, with an estimated increase in incidence to 23.6 million by 2030. 1 Cardiovascular death represents 31% of all global deaths 2 -with stroke, heart attack, and ruptured aneurysms predominantly contributing to these high mortality rates. A key risk factor for cardiovascular disease is hypertension. Although treatment or reduction in hypertension can prevent the onset of cardiovascular events, existing therapies are only partially effective. A key pathological hallmark of hypertension is increased peripheral vascular resistance because of structural and functional changes in large (conductive) and small (resistance) arteries. In this review, we discuss the clinical implications of vascular remodeling, compare the differences between vascular smooth muscle cell remodeling in conductive and resistance arteries, discuss the genetic factors associated with vascular smooth muscle cell function in hypertensive patients, and provide a prospective assessment of current and future research and pharmacological targets for the treatment of hypertension.
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Affiliation(s)
- Isola A M Brown
- From the Robert M. Berne Cardiovascular Research Center (I.A.M.B., M.E.G., L.J.D., S.A.M., B.E.I.)
| | - Lukas Diederich
- Cardiovascular Research Laboratory, Division of Cardiology, Pneumology and Angiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany (L.D., M.M.C.-K.)
| | - Miranda E Good
- From the Robert M. Berne Cardiovascular Research Center (I.A.M.B., M.E.G., L.J.D., S.A.M., B.E.I.)
| | - Leon J DeLalio
- From the Robert M. Berne Cardiovascular Research Center (I.A.M.B., M.E.G., L.J.D., S.A.M., B.E.I.).,Department of Pharmacology (L.J.D.)
| | - Sara A Murphy
- From the Robert M. Berne Cardiovascular Research Center (I.A.M.B., M.E.G., L.J.D., S.A.M., B.E.I.)
| | - Miriam M Cortese-Krott
- Cardiovascular Research Laboratory, Division of Cardiology, Pneumology and Angiology, Medical Faculty, Heinrich Heine University, Dusseldorf, Germany (L.D., M.M.C.-K.)
| | - Jennifer L Hall
- Lillehei Heart Institute (J.L.H.).,Division of Cardiology, Department of Medicine (J.L.H.), University of Minnesota, Minneapolis.,American Heart Association, Dallas, TX (J.L.H.)
| | - Thu H Le
- Division of Nephrology, Department of Medicine (T.H.L.)
| | - Brant E Isakson
- From the Robert M. Berne Cardiovascular Research Center (I.A.M.B., M.E.G., L.J.D., S.A.M., B.E.I.).,Department of Molecular Physiology and Biophysics (B.E.I.), University of Virginia School of Medicine, Charlottesville
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58
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Novielli-Kuntz NM, Jelen M, Barr K, DeLalio LJ, Feng Q, Isakson BE, Gros R, Laird DW. Ablation of both Cx40 and Panx1 results in similar cardiovascular phenotypes exhibited in Cx40 knockout mice. Biosci Rep 2019; 39:BSR20182350. [PMID: 30745457 PMCID: PMC6393227 DOI: 10.1042/bsr20182350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Revised: 01/10/2019] [Accepted: 02/05/2019] [Indexed: 11/30/2022] Open
Abstract
Connexins (Cxs) and pannexins (Panxs) are highly regulated large-pore channel-forming proteins that participate in cellular communication via small molecular exchange with the extracellular microenvironment, or in the case of connexins, directly between cells. Given the putative functional overlap between single membrane-spanning connexin hemichannels and Panx channels, and cardiovascular system prevalence, we generated the first Cx40-/-Panx1-/- mouse with the anticipation that this genetic modification would lead to a severe cardiovascular phenotype. Mice null for both Cx40 and Panx1 produced litter sizes and adult growth progression similar to wild-type (WT), Cx40-/- and Panx1-/- mice. Akin to Cx40-/- mice, Cx40-/-Panx1-/- mice exhibited cardiac hypertrophy and elevated systolic, diastolic, and mean arterial blood pressure compared with WT and Panx1-/- mice; however assessment of left ventricular ejection fraction and fractional shortening revealed no evidence of cardiac dysfunction between groups. Furthermore, Cx40-/-, Panx1-/-, and Cx40-/-Panx1-/- mice demonstrated impaired endothelial-mediated vasodilation of aortic segments to increasing concentrations of methacholine (MCh) compared with WT, highlighting roles for both Cx40 and Panx1 in vascular endothelial cell (EC) function. Surprisingly, elevated kidney renin mRNA expression, plasma renin activity, and extraglomerular renin-producing cell populations found in Cx40-/- mice was further exaggerated in double knockout mice. Thus, while gestation and gross development were conserved in Cx40-/-Panx1-/- mice, they exhibit cardiac hypertrophy, hypertension, and impaired endothelial-mediated vasodilation that phenocopies Cx40-/- mice. Nevertheless, the augmented renin homeostasis observed in the double knockout mice suggests that both Cx40 and Panx1 may play an integrative role.
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Affiliation(s)
| | - Meghan Jelen
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
| | - Kevin Barr
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
| | - Leon J DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, U.S.A
| | - Qingping Feng
- Department of Physiology and Pharmacology London, ON, Canada
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, U.S.A
| | - Robert Gros
- Department of Physiology and Pharmacology London, ON, Canada
- Robarts Research Institute, Schulich School of Medicine & Dentistry, University of Western Ontario, London, ON, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Canada
- Department of Physiology and Pharmacology London, ON, Canada
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59
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DeLalio LJ, Billaud M, Ruddiman CA, Johnstone SR, Butcher JT, Wolpe AG, Jin X, Keller TCS, Keller AS, Rivière T, Good ME, Best AK, Lohman AW, Swayne LA, Penuela S, Thompson RJ, Lampe PD, Yeager M, Isakson BE. Constitutive SRC-mediated phosphorylation of pannexin 1 at tyrosine 198 occurs at the plasma membrane. J Biol Chem 2019; 294:6940-6956. [PMID: 30814251 DOI: 10.1074/jbc.ra118.006982] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/15/2019] [Indexed: 11/06/2022] Open
Abstract
Pannexin 1 (PANX1)-mediated ATP release in vascular smooth muscle coordinates α1-adrenergic receptor (α1-AR) vasoconstriction and blood pressure homeostasis. We recently identified amino acids 198-200 (YLK) on the PANX1 intracellular loop that are critical for α1-AR-mediated vasoconstriction and PANX1 channel function. We report herein that the YLK motif is contained within an SRC homology 2 domain and is directly phosphorylated by SRC proto-oncogene, nonreceptor tyrosine kinase (SRC) at Tyr198 We demonstrate that PANX1-mediated ATP release occurs independently of intracellular calcium but is sensitive to SRC family kinase (SFK) inhibition, suggestive of channel regulation by tyrosine phosphorylation. Using a PANX1 Tyr198-specific antibody, SFK inhibitors, SRC knockdown, temperature-dependent SRC cells, and kinase assays, we found that PANX1-mediated ATP release and vasoconstriction involves constitutive phosphorylation of PANX1 Tyr198 by SRC. We specifically detected SRC-mediated Tyr198 phosphorylation at the plasma membrane and observed that it is not enhanced or induced by α1-AR activation. Last, we show that PANX1 immunostaining is enriched in the smooth muscle layer of arteries from hypertensive humans and that Tyr198 phosphorylation is detectable in these samples, indicative of a role for membrane-associated PANX1 in small arteries of hypertensive humans. Our discovery adds insight into the regulation of PANX1 by post-translational modifications and connects a significant purinergic vasoconstriction pathway with a previously identified, yet unexplored, tyrosine kinase-based α1-AR constriction mechanism. This work implicates SRC-mediated PANX1 function in normal vascular hemodynamics and suggests that Tyr198-phosphorylated PANX1 is involved in hypertensive vascular pathology.
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Affiliation(s)
- Leon J DeLalio
- From the Robert M. Berne Cardiovascular Research Center.,Department of Pharmacology
| | - Marie Billaud
- the Department of Cardiothoracic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15213
| | - Claire A Ruddiman
- From the Robert M. Berne Cardiovascular Research Center.,Department of Pharmacology
| | | | - Joshua T Butcher
- the Department of Physiology, Augusta University, Augusta, Georgia 30912
| | - Abigail G Wolpe
- From the Robert M. Berne Cardiovascular Research Center.,Department of Cell Biology, and
| | - Xueyao Jin
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - T C Stevenson Keller
- From the Robert M. Berne Cardiovascular Research Center.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Alexander S Keller
- From the Robert M. Berne Cardiovascular Research Center.,Department of Pharmacology
| | - Thibaud Rivière
- the Department of Life and Health Sciences, University of Bordeaux, 33000 Bordeaux, France
| | | | - Angela K Best
- From the Robert M. Berne Cardiovascular Research Center
| | - Alexander W Lohman
- the Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Leigh Anne Swayne
- the Division of Medical Sciences, Centre for Biomedical Research, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Silvia Penuela
- the Departments of Anatomy and Cell Biology and Oncology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, Ontario N6A 3K7, Canada, and
| | - Roger J Thompson
- the Hotchkiss Brain Institute and.,Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta T2N 4N1, Canada
| | - Paul D Lampe
- the Fred Hutchinson Cancer Research Center, Seattle, Washington 98109
| | - Mark Yeager
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
| | - Brant E Isakson
- From the Robert M. Berne Cardiovascular Research Center, .,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, Virginia 22908
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60
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Michalski K, Henze E, Nguyen P, Lynch P, Kawate T. The weak voltage dependence of pannexin 1 channels can be tuned by N-terminal modifications. J Gen Physiol 2018; 150:1758-1768. [PMID: 30377218 PMCID: PMC6279361 DOI: 10.1085/jgp.201711804] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 09/29/2018] [Accepted: 10/16/2018] [Indexed: 12/13/2022] Open
Abstract
Voltage stimulation is commonly used to study pannexin 1 (Panx1). However, whether Panx1 is a voltage-gated channel remains controversial. Michalski et al. demonstrate that Panx1 is a channel with weak voltage dependence, whose activity can be tuned by N-terminal modifications. Pannexins are a family of ATP release channels important for physiological and pathological processes like blood pressure regulation, epilepsy, and neuropathic pain. To study these important channels in vitro, voltage stimulation is the most common and convenient tool, particularly for pannexin 1 (Panx1). However, whether Panx1 is a voltage-gated channel remains controversial. Here, we carefully examine the effect of N-terminal modification on voltage-dependent Panx1 channel activity. Using a whole-cell patch-clamp recording technique, we demonstrate that both human and mouse Panx1, with their nativeN termini, give rise to voltage-dependent currents, but only at membrane potentials larger than +100 mV. This weak voltage-dependent channel activity profoundly increases when a glycine–serine (GS) motif is inserted immediately after the first methionine. Single-channel recordings reveal that the addition of GS increases the channel open probability as well as the number of unitary conductance classes. We also find that insertions of other amino acid(s) at the same position mimics the effect of GS. On the other hand, tagging the N terminus with GFP abolishes voltage-dependent channel activity. Our results suggest that Panx1 is a channel with weak voltage dependence whose activity can be tuned by N-terminal modifications.
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Affiliation(s)
- Kevin Michalski
- Department of Molecular Medicine, Fields of Biochemistry, Molecular, and Cell Biology (BMCB), and Biophysics, Cornell University, Ithaca, NY
| | - Erik Henze
- Department of Molecular Medicine, Fields of Biochemistry, Molecular, and Cell Biology (BMCB), and Biophysics, Cornell University, Ithaca, NY
| | - Phillip Nguyen
- Department of Molecular Medicine, Fields of Biochemistry, Molecular, and Cell Biology (BMCB), and Biophysics, Cornell University, Ithaca, NY
| | - Patrick Lynch
- Department of Molecular Medicine, Fields of Biochemistry, Molecular, and Cell Biology (BMCB), and Biophysics, Cornell University, Ithaca, NY
| | - Toshimitsu Kawate
- Department of Molecular Medicine, Fields of Biochemistry, Molecular, and Cell Biology (BMCB), and Biophysics, Cornell University, Ithaca, NY
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61
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Abstract
The connexin family of channel-forming proteins is present in every tissue type in the human anatomy. Connexins are best known for forming clustered intercellular channels, structurally known as gap junctions, where they serve to exchange members of the metabolome between adjacent cells. In their single-membrane hemichannel form, connexins can act as conduits for the passage of small molecules in autocrine and paracrine signalling. Here, we review the roles of connexins in health and disease, focusing on the potential of connexins as therapeutic targets in acquired and inherited diseases as well as wound repair, while highlighting the associated clinical challenges.
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62
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Li S, Li J, Wang N, Zhang T, Xu Y, Sun J. Expression analysis of Pannexin1 channel gene in response to immune challenges and its role in infection-induced ATP release in tilapia (Oreochromis niloticus). FISH & SHELLFISH IMMUNOLOGY 2018; 81:470-475. [PMID: 30064016 DOI: 10.1016/j.fsi.2018.07.050] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 07/21/2018] [Accepted: 07/27/2018] [Indexed: 06/08/2023]
Abstract
ATP released from immune cells plays an important role in activation of host innate immunity. However, the molecular mechanisms for pathogen infection-induced ATP release in fish remains unclear. Pannexin1 (Panx1) is a recently identified ATP release channel important for controlling immune responses. The immune relevance of Panx1 in fish, however, is still poorly understood. In this study, we characterized a Panx1 gene homologue (termed tPanx1) from Nile tilapia (Oreochromis niloticus) and analyzed its expression in response to different immune challenges. We also investigated the role of tPanx1 channel in bacterial infection-induced ATP release. Real-time quantitative PCR analysis revealed that tPanx1 gene is expressed in all tested tissues with predominant expression in intestine. Immune challenges with lipopolysaccharide, polyinosinic-polycytidylic acid and zymosan led to increased gene expression of tPanx1 in tilapia head kidney cells and peripheral blood leucocytes. In addition, tPanx1 gene was up-regulated in hepatopancreas, muscle, spleen, gill, head kidney and blood after Aeromonas hydrophila infection. Furthermore, pharmacological inhibition of tPanx1 channel activity with Panx1 channel inhibitor, carbenoxolone, significantly attenuated A. hydrophila infection-induced ATP release in tilapia head kidney cells. Taken together, our findings suggested that tPanx1 is an important immune response gene involved in bacterial infection-induced ATP release in tilapia O. niloticus.
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Affiliation(s)
- Shuo Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China.
| | - Jiafang Li
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China
| | - Nan Wang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China
| | - Tianxu Zhang
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China
| | - Yaqi Xu
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China
| | - Jinsheng Sun
- Tianjin Key Laboratory of Animal and Plant Resistance, College of Life Sciences, Tianjin Normal University, 393 West Binshui Road, Xiqing District, Tianjin 300387, China.
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63
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DeLalio LJ, Keller AS, Chen J, Boyce AK, Artamonov M, Askew-Page HR, Keller TS, Johnstone SR, Weaver RB, Good ME, Murphy S, Best AK, Mintz EL, Penuela S, Greenwood I, Machado RF, Somlyo AV, Swayne LA, Minshall R, Isakson BE. Interaction Between Pannexin 1 and Caveolin-1 in Smooth Muscle Can Regulate Blood Pressure. Arterioscler Thromb Vasc Biol 2018; 38:2065-2078. [PMID: 30026274 PMCID: PMC6202122 DOI: 10.1161/atvbaha.118.311290] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 06/19/2018] [Indexed: 12/31/2022]
Abstract
Objective- Sympathetic nerve innervation of vascular smooth muscle cells (VSMCs) is a major regulator of arteriolar vasoconstriction, vascular resistance, and blood pressure. Importantly, α-adrenergic receptor stimulation, which uniquely couples with Panx1 (pannexin 1) channel-mediated ATP release in resistance arteries, also requires localization to membrane caveolae. Here, we test whether localization of Panx1 to Cav1 (caveolin-1) promotes channel function (stimulus-dependent ATP release and adrenergic vasoconstriction) and is important for blood pressure homeostasis. Approach and Results- We use in vitro VSMC culture models, ex vivo resistance arteries, and a novel inducible VSMC-specific Cav1 knockout mouse to probe interactions between Panx1 and Cav1. We report that Panx1 and Cav1 colocalized on the VSMC plasma membrane of resistance arteries near sympathetic nerves in an adrenergic stimulus-dependent manner. Genetic deletion of Cav1 significantly blunts adrenergic-stimulated ATP release and vasoconstriction, with no direct influence on endothelium-dependent vasodilation or cardiac function. A significant reduction in mean arterial pressure (total=4 mm Hg; night=7 mm Hg) occurred in mice deficient for VSMC Cav1. These animals were resistant to further blood pressure lowering using a Panx1 peptide inhibitor Px1IL2P, which targets an intracellular loop region necessary for channel function. Conclusions- Translocalization of Panx1 to Cav1-enriched caveolae in VSMCs augments the release of purinergic stimuli necessary for proper adrenergic-mediated vasoconstriction and blood pressure homeostasis.
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Affiliation(s)
- Leon J. DeLalio
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Alexander S. Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Jiwang Chen
- Department of Medicine, The University of Illinois at Chicago, Chicago, IL
| | - Andrew K.J. Boyce
- Division of Medical Sciences, Centre for Biomedical Research, University of Victoria, Victoria, BC Canada
| | - Mykhaylo Artamonov
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
| | - Henry R. Askew-Page
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - T.C. Stevenson Keller
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
| | - Scott R. Johnstone
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Rachel B. Weaver
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Miranda E. Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Sara Murphy
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Angela K. Best
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
| | - Ellen L. Mintz
- Department of Biomedical Engineering, University of Virginia School of Engineering, Charlottesville, VA
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, Schulich Scholl of Medicine and Dentistry, University of Western Ontario, London ON, Canada
| | - Iain Greenwood
- Molecular and Clinical Sciences Research Institute, St. George’s University London UK
| | - Roberto F. Machado
- Division of Pulmonary, Critical Care, Sleep, & Occupational Medicine, Indiana University School of Medicine, Indianapolis, IN
| | - Avril V. Somlyo
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
| | - Leigh Anne Swayne
- Division of Medical Sciences, Centre for Biomedical Research, University of Victoria, Victoria, BC Canada
| | - Richard Minshall
- Department of Pharmacology and Department of Anesthesiology, The University of Illinois at Chicago, Chicago, IL
| | - Brant E. Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA
- Department of Molecular Physiology and Biophysics, University of Virginia, Charlottesville, VA
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64
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Htet M, Nally JE, Shaw A, Foote BE, Martin PE, Dempsie Y. Connexin 43 Plays a Role in Pulmonary Vascular Reactivity in Mice. Int J Mol Sci 2018; 19:E1891. [PMID: 29954114 PMCID: PMC6073802 DOI: 10.3390/ijms19071891] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Revised: 06/07/2018] [Accepted: 06/20/2018] [Indexed: 11/25/2022] Open
Abstract
Pulmonary arterial hypertension (PAH) is a chronic condition characterized by vascular remodeling and increased vaso-reactivity. PAH is more common in females than in males (~3:1). Connexin (Cx)43 has been shown to be involved in cellular communication within the pulmonary vasculature. Therefore, we investigated the role of Cx43 in pulmonary vascular reactivity using Cx43 heterozygous (Cx43+/−) mice and 37,43Gap27, which is a pharmacological inhibitor of Cx37 and Cx43. Contraction and relaxation responses were studied in intra-lobar pulmonary arteries (IPAs) derived from normoxic mice and hypoxic mice using wire myography. IPAs from male Cx43+/− mice displayed a small but significant increase in the contractile response to endothelin-1 (but not 5-hydroxytryptamine) under both normoxic and hypoxic conditions. There was no difference in the contractile response to endothelin-1 (ET-1) or 5-hydroxytryptamine (5-HT) in IPAs derived from female Cx43+/−mice compared to wildtype mice. Relaxation responses to methacholine (MCh) were attenuated in IPAs from male and female Cx43+/− mice or by pre-incubation of IPAs with 37,43Gap27. Nω-Nitro-L-arginine methyl ester (l-NAME) fully inhibited MCh-induced relaxation. In conclusion, Cx43 is involved in nitric oxide (NO)-induced pulmonary vascular relaxation and plays a gender-specific and agonist-specific role in pulmonary vascular contractility. Therefore, reduced Cx43 signaling may contribute to pulmonary vascular dysfunction.
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Affiliation(s)
- Myo Htet
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Jane E Nally
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Andrew Shaw
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Bradley E Foote
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Patricia E Martin
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
| | - Yvonne Dempsie
- Department of Life Sciences, School of Health and Life Sciences, Glasgow Caledonian University, Glasgow G4 0BA, UK.
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65
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Makarenkova HP, Shah SB, Shestopalov VI. The two faces of pannexins: new roles in inflammation and repair. J Inflamm Res 2018; 11:273-288. [PMID: 29950881 PMCID: PMC6016592 DOI: 10.2147/jir.s128401] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Pannexins belong to a family of ATP-release channels expressed in almost all cell types. An increasing body of literature on pannexins suggests that these channels play dual and sometimes contradictory roles, contributing to normal cell function, as well as to the pathological progression of disease. In this review, we summarize our understanding of pannexin "protective" and "harmful" functions in inflammation, regeneration and mechanical signaling. We also suggest a possible basis for pannexin's dual roles, related to extracellular ATP and K+ levels and the activation of various types of P2 receptors that are associated with pannexin. Finally, we speculate upon therapeutic strategies related to pannexin using eyes, lacrimal glands, and peripheral nerves as examples of interesting therapeutic targets.
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Affiliation(s)
| | - Sameer B Shah
- Departments of Orthopaedic Surgery and Bioengineering, University of California.,Research Division, Veterans Affairs San Diego Healthcare System, San Diego, CA
| | - Valery I Shestopalov
- Bascom Eye Institute, Department of Ophthalmology, University of Miami, Miami, FL, USA.,Vavilov Institute for General Genetics, Russian Academy of Sciences.,Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow, Russia
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66
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Molica F, Figueroa XF, Kwak BR, Isakson BE, Gibbins JM. Connexins and Pannexins in Vascular Function and Disease. Int J Mol Sci 2018; 19:ijms19061663. [PMID: 29874791 PMCID: PMC6032213 DOI: 10.3390/ijms19061663] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/28/2018] [Accepted: 05/31/2018] [Indexed: 12/24/2022] Open
Abstract
Connexins (Cxs) and pannexins (Panxs) are ubiquitous membrane channel forming proteins that are critically involved in many aspects of vascular physiology and pathology. The permeation of ions and small metabolites through Panx channels, Cx hemichannels and gap junction channels confers a crucial role to these proteins in intercellular communication and in maintaining tissue homeostasis. This review provides an overview of current knowledge with respect to the pathophysiological role of these channels in large arteries, the microcirculation, veins, the lymphatic system and platelet function. The essential nature of these membrane proteins in vascular homeostasis is further emphasized by the pathologies that are linked to mutations and polymorphisms in Cx and Panx genes.
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Affiliation(s)
- Filippo Molica
- Department of Pathology and Immunology, University of Geneva, CH-1211 Geneva, Switzerland.
| | - Xavier F Figueroa
- Departamento de Fisiología, Faculdad de Ciencias Biológicas, Pontifica Universidad Católica de Chile, Santiago 8330025, Chile.
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, CH-1211 Geneva, Switzerland.
| | - Brant E Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA 22908, USA.
| | - Jonathan M Gibbins
- Institute for Cardiovascular & Metabolic Research, School of Biological Sciences, Harborne Building, University of Reading, Reading RG6 6AS, UK.
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67
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Yamada T, Strange K. Intracellular and extracellular loops of LRRC8 are essential for volume-regulated anion channel function. J Gen Physiol 2018; 150:1003-1015. [PMID: 29853476 PMCID: PMC6028502 DOI: 10.1085/jgp.201812016] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 04/02/2018] [Accepted: 05/01/2018] [Indexed: 12/13/2022] Open
Abstract
The volume-regulated anion channel (VRAC) is expressed ubiquitously in vertebrate cells and mediates swelling-induced release of Cl- and organic solutes. Recent studies by several laboratories have demonstrated conclusively that VRAC is encoded by members of the leucine-rich repeat containing 8 (Lrrc8) gene family, which comprises five members, termed Lrrc8a-e. Numerous observations indicate that VRAC is a heteromeric channel comprising the essential subunit LRRC8A and one or more of the other LRRC8 paralogs. Here we demonstrate that the intracellular loop (IL) connecting transmembrane domains 2 and 3 of LRRC8A and the first extracellular loop (EL1) connecting transmembrane domains 1 and 2 of LRRC8C, LRRC8D, or LRRC8E are both essential for VRAC activity. We generate homomeric VRACs by replacing EL1 of LRRC8A with that of LRRC8C and demonstrate normal regulation by cell swelling and shrinkage. We also observe normal volume-dependent regulation in VRAC homomers in which the IL of LRRC8C, LRRC8D, or LRRC8E is replaced with the LRRC8A IL. A 25-amino acid sequence unique to the LRRC8A IL is sufficient to generate homomeric VRAC activity when inserted into the corresponding region of LRRC8C and LRRC8E. LRRC8 chimeras containing these partial LRRC8A IL sequences exhibit altered anion permeability, rectification, and voltage sensitivity, suggesting that the LRRC8A IL plays a role in VRAC pore structure and function. Our studies provide important new insights into the structure/function roles of the LRRC8 EL1 and IL. Homomeric LRRC8 channels will simplify future studies aimed at understanding channel structure and the longstanding and vexing problem of how VRAC is regulated by cell volume changes.
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68
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Good ME, Chiu YH, Poon IKH, Jaffe IZ, Bayliss DA, Isakson BE, Ravichandran KS. Response by Good et al to Letter Regarding Article, "Pannexin-1 Channels as an Unexpected New Target of the Antihypertensive Drug Spironolactone". Circ Res 2018; 122:e88-e89. [PMID: 29798905 DOI: 10.1161/circresaha.118.313080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Miranda E Good
- Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville
| | - Ivan K H Poon
- Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia
| | - Iris Z Jaffe
- Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville
| | - Brant E Isakson
- Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, and Cancer Biology, University of Virginia School of Medicine, Charlottesville
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69
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Wang J, Dahl G. Pannexin1: a multifunction and multiconductance and/or permeability membrane channel. Am J Physiol Cell Physiol 2018; 315:C290-C299. [PMID: 29719171 DOI: 10.1152/ajpcell.00302.2017] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Of the three pannexins in vertebrate proteomes, pannexin1 (Panx1) is the only one well characterized, and it is generally accepted that Panx1 functions as an ATP release channel for signaling to other cells. However, the ATP permeability of the channel is only observed with certain stimuli, including low oxygen, mechanical stress, and elevated extracellular potassium ion concentration. Otherwise, the Panx1 channel is selective for chloride ions and exhibits no ATP permeability when stimulated simply by depolarization to positive potentials. A third, irreversible activation of Panx1 follows cleavage of carboxyterminal amino acids by caspase 3. The selectivity/permeability properties of the caspase cleaved channel are unclear as it reportedly has features of both channel conformations. Here we describe the biophysical properties of the channel formed by the truncation mutant Panx1Δ378, which is identical to the caspase-cleaved protein. Consistent with previous findings for the caspase-activated channel, the Panx1Δ378 channel was constitutively active. However, like the voltage-gated channel, the Panx1Δ378 channel had high chloride selectivity, lacked cation permeability, and did not mediate ATP release unless stimulated by extracellular potassium ions. Thus, the caspase-cleaved Panx1 channel should be impermeable to ATP, contrary to previous claims.
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Affiliation(s)
- Junjie Wang
- Department of Physiology and Biophysics, University of Miami School of Medicine , Miami, Florida
| | - Gerhard Dahl
- Department of Physiology and Biophysics, University of Miami School of Medicine , Miami, Florida
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70
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Good ME, Eucker SA, Li J, Bacon HM, Lang SM, Butcher JT, Johnson TJ, Gaykema RP, Patel MK, Zuo Z, Isakson BE. Endothelial cell Pannexin1 modulates severity of ischemic stroke by regulating cerebral inflammation and myogenic tone. JCI Insight 2018; 3:96272. [PMID: 29563335 PMCID: PMC5926909 DOI: 10.1172/jci.insight.96272] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 02/16/2018] [Indexed: 12/24/2022] Open
Abstract
Ischemic stroke is a leading cause of morbidity and mortality in the US; however, there currently exists only one effective acute pharmacological therapeutic intervention. Purinergic signaling has been shown to regulate vascular function and pathological processes, including inflammation and arterial myogenic reactivity, and plays a role in ischemic stroke outcome. Purinergic signaling requires extracellular purines; however, the mechanism of purine release from cells is unclear. Pannexin1 (Panx1) channels are potentially novel purine release channels expressed throughout the vascular tree that couples regulated purine release with purinergic signaling. Therefore, we examined the role of smooth muscle and endothelial cell Panx1, using conditional cell type-specific transgenic mice, in cerebral ischemia/reperfusion injury outcomes. Deletion of endothelial cell Panx1, but not smooth muscle cell Panx1, significantly reduced cerebral infarct volume after ischemia/reperfusion. Infiltration of leukocytes into brain tissue and development of cerebral myogenic tone were both significantly reduced when mice lacked endothelial Panx1. Panx1 regulation of myogenic tone was unique to the cerebral circulation, as mesenteric myogenic reactivity and blood pressure were independent of endothelial Panx1. Overall, deletion of endothelial Panx1 mitigated cerebral ischemic injury by reducing inflammation and myogenic tone development, indicating that endothelial Panx1 is a possible novel target for therapeutic intervention of ischemic stroke.
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Affiliation(s)
- Miranda E Good
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Stephanie A. Eucker
- Division of Emergency Medicine, Department of Surgery, Duke University, Durham, North Carolina, USA
| | - Jun Li
- Department of Anesthesiology and
| | - Hannah M. Bacon
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Susan M. Lang
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Joshua T. Butcher
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - Tyler J. Johnson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | | | | | | | - Brant E. Isakson
- Robert M. Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia, USA
- Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, University of Virginia School of Medicine, Charlottesville, Virginia, USA
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71
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Nyberg M, Piil P, Kiehn OT, Maagaard C, Jørgensen TS, Egelund J, Isakson BE, Nielsen MS, Gliemann L, Hellsten Y. Probenecid Inhibits α-Adrenergic Receptor-Mediated Vasoconstriction in the Human Leg Vasculature. Hypertension 2018; 71:151-159. [PMID: 29084879 PMCID: PMC5876717 DOI: 10.1161/hypertensionaha.117.10251] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Revised: 09/11/2017] [Accepted: 10/09/2017] [Indexed: 01/07/2023]
Abstract
Coordination of vascular smooth muscle cell tone in resistance arteries plays an essential role in the regulation of peripheral resistance and overall blood pressure. Recent observations in animals have provided evidence for a coupling between adrenoceptors and Panx1 (pannexin-1) channels in the regulation of sympathetic nervous control of peripheral vascular resistance and blood pressure; however, evidence for a functional coupling in humans is lacking. We determined Panx1 expression and effects of treatment with the pharmacological Panx1 channel inhibitor probenecid on the vasoconstrictor response to α1- and α2-adrenergic receptor stimulation in the human forearm and leg vasculature of young healthy male subjects (23±3 years). By use of immunolabeling and confocal microscopy, Panx1 channels were found to be expressed in vascular smooth muscle cells of arterioles in human leg skeletal muscle. Probenecid treatment increased (P<0.05) leg vascular conductance at baseline by ≈15% and attenuated (P<0.05) the leg vasoconstrictor response to arterial infusion of tyramine (α1- and α2-adrenergic receptor stimulation) by ≈15%, whereas the response to the α1-agonist phenylephrine was unchanged. Inhibition of α1-adrenoceptors prevented the probenecid-induced increase in baseline leg vascular conductance, but did not alter the effect of probenecid on the vascular response to tyramine. No differences with probenecid treatment were detected in the forearm. These observations provide the first line of evidence in humans for a functional role of Panx1 channels in setting resting tone via α1-adrenoceptors and in the constrictive effect of noradrenaline via α2-adrenoceptors, thereby contributing to the regulation of peripheral vascular resistance and blood pressure in humans.
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Affiliation(s)
- Michael Nyberg
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Peter Piil
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Oliver T Kiehn
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Christian Maagaard
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Tue S Jørgensen
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Jon Egelund
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Brant E Isakson
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Morten S Nielsen
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Lasse Gliemann
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.)
| | - Ylva Hellsten
- From the Department of Nutrition, Exercise and Sports (M.N., P.P., O.T.K., C.M., T.S.J., J.E., L.G., Y.H.) and Department of Biomedical Sciences, Faculty of Health and Medical Sciences (M.S.N.), University of Copenhagen, Denmark; Department of Orthopedics, Herlev and Gentofte Hospital, Hellerup, Denmark (T.S.J.); and Department of Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville (B.E.I.).
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Good ME, Chiu YH, Poon IKH, Medina CB, Butcher JT, Mendu SK, DeLalio LJ, Lohman AW, Leitinger N, Barrett E, Lorenz UM, Desai BN, Jaffe IZ, Bayliss DA, Isakson BE, Ravichandran KS. Pannexin 1 Channels as an Unexpected New Target of the Anti-Hypertensive Drug Spironolactone. Circ Res 2017; 122:606-615. [PMID: 29237722 DOI: 10.1161/circresaha.117.312380] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2017] [Revised: 12/06/2017] [Accepted: 12/12/2017] [Indexed: 12/16/2022]
Abstract
RATIONALE Resistant hypertension is a major health concern with unknown cause. Spironolactone is an effective antihypertensive drug, especially for patients with resistant hypertension, and is considered by the World Health Organization as an essential medication. Although spironolactone can act at the mineralocorticoid receptor (MR; NR3C2), there is increasing evidence of MR-independent effects of spironolactone. OBJECTIVE Here, we detail the unexpected discovery that Panx1 (pannexin 1) channels could be a relevant in vivo target of spironolactone. METHODS AND RESULTS First, we identified spironolactone as a potent inhibitor of Panx1 in an unbiased small molecule screen, which was confirmed by electrophysiological analysis. Next, spironolactone inhibited α-adrenergic vasoconstriction in arterioles from mice and hypertensive humans, an effect dependent on smooth muscle Panx1, but independent of the MR NR3C2. Last, spironolactone acutely lowered blood pressure, which was dependent on smooth muscle cell expression of Panx1 and independent of NR3C2. This effect, however, was restricted to steroidal MR antagonists as a nonsteroidal MR antagonist failed to reduced blood pressure. CONCLUSIONS These data suggest new therapeutic modalities for resistant hypertension based on Panx1 inhibition.
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Affiliation(s)
- Miranda E Good
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Yu-Hsin Chiu
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Ivan K H Poon
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Christopher B Medina
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Joshua T Butcher
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Suresh K Mendu
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Leon J DeLalio
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Alexander W Lohman
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Norbert Leitinger
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Eugene Barrett
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Ulrike M Lorenz
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Bimal N Desai
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Iris Z Jaffe
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Douglas A Bayliss
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
| | - Brant E Isakson
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.).
| | - Kodi S Ravichandran
- From the Department of Molecular Physiology and Biophysics, Robert M. Berne Cardiovascular Research Center (M.E.G., J.T.B., L.J.D., A.W.L., B.E.I.), Department of Pharmacology (Y.-H.C., S.K.M., N.L., B.N.D., D.A.B.), Department of Microbiology, Immunology and Cancer Biology, the Center for Cell Clearance, and the Beirne B. Carter Center for Immunology Research (C.B.M., U.M.L., K.S.R.), and Division of Endocrinology (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Biochemistry and Genetics, La Trobe University, Melbourne, Australia (I.K.H.P.); and Molecular Cardiology Research Institute, Tufts Medical Center, Boston, MA (I.Z.J.)
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Chiu YH, Schappe MS, Desai BN, Bayliss DA. Revisiting multimodal activation and channel properties of Pannexin 1. J Gen Physiol 2017; 150:19-39. [PMID: 29233884 PMCID: PMC5749114 DOI: 10.1085/jgp.201711888] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2017] [Accepted: 11/09/2017] [Indexed: 12/23/2022] Open
Abstract
Pannexin 1 (Panx1) forms plasma membrane ion channels that are widely expressed throughout the body. Panx1 activation results in the release of nucleotides such as adenosine triphosphate and uridine triphosphate. Thus, these channels have been implicated in diverse physiological and pathological functions associated with purinergic signaling, such as apoptotic cell clearance, blood pressure regulation, neuropathic pain, and excitotoxicity. In light of this, substantial attention has been directed to understanding the mechanisms that regulate Panx1 channel expression and activation. Here we review accumulated evidence for the various activation mechanisms described for Panx1 channels and, where possible, the unitary channel properties associated with those forms of activation. We also emphasize current limitations in studying Panx1 channel function and propose potential directions to clarify the exciting and expanding roles of Panx1 channels.
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Affiliation(s)
- Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Michael S Schappe
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Bimal N Desai
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia School of Medicine, Charlottesville, VA
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74
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Lohman AW, Weilinger NL, Santos SM, Bialecki J, Werner AC, Anderson CL, Thompson RJ. Regulation of pannexin channels in the central nervous system by Src family kinases. Neurosci Lett 2017; 695:65-70. [PMID: 28911820 DOI: 10.1016/j.neulet.2017.09.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 07/24/2017] [Accepted: 09/10/2017] [Indexed: 02/06/2023]
Abstract
Pannexins form single membrane channels that regulate the passage of ions, small molecules and metabolites between the intra- and extracellular compartments. In the central nervous system, these channels are integrated into numerous signaling cascades that shape brain physiology and pathology. Post-translational modification of pannexins is complex, with phosphorylation emerging as a prominent form of functional regulation. While much is still not known regarding the specific kinases and modified amino acids, recent reports support a role for Src family tyrosine kinases (SFK) in regulating pannexin channel activity. This review outlines the current evidence supporting SFK-dependent pannexin phosphorylation in the CNS and examines the importance of these modifications in the healthy and diseased brain.
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Affiliation(s)
- Alexander W Lohman
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Nicholas L Weilinger
- Djavad Mowafaghian Centre for Brain Health, Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Silva Mf Santos
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Jennifer Bialecki
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Allison C Werner
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Connor L Anderson
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
| | - Roger J Thompson
- Department of Cell Biology and Anatomy, University of Calgary, Calgary, Alberta, Canada; Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada.
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75
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Shestopalov VI, Panchin Y, Tarasova OS, Gaynullina D, Kovalzon VM. Pannexins Are Potential New Players in the Regulation of Cerebral Homeostasis during Sleep-Wake Cycle. Front Cell Neurosci 2017; 11:210. [PMID: 28769767 PMCID: PMC5511838 DOI: 10.3389/fncel.2017.00210] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Accepted: 07/03/2017] [Indexed: 12/18/2022] Open
Abstract
During brain homeostasis, both neurons and astroglia release ATP that is rapidly converted to adenosine in the extracellular space. Pannexin-1 (Panx1) hemichannels represent a major conduit of non-vesicular ATP release from brain cells. Previous studies have shown that Panx1−/− mice possess severe disruption of the sleep-wake cycle. Here, we review experimental data supporting the involvement of pannexins (Panx) in the coordination of fundamental sleep-associated brain processes, such as neuronal activity and regulation of cerebrovascular tone. Panx1 hemichannels are likely implicated in the regulation of the sleep-wake cycle via an indirect effect of released ATP on adenosine receptors and through interaction with other somnogens, such as IL-1β, TNFα and prostaglandin D2. In addition to the recently established role of Panx1 in the regulation of endothelium-dependent arterial dilation, similar signaling pathways are the major cellular component of neurovascular coupling. The new discovered role of Panx in sleep regulation may have broad implications in coordinating neuronal activity and homeostatic housekeeping processes during the sleep-wake cycle.
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Affiliation(s)
- Valery I Shestopalov
- Institute for Information Transmission Problems, Russian Academy of SciencesMoscow, Russia.,Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of MedicineMiami, FL, United States.,Microbiology and Bioengineering Laboratory, Department of Genomics and Biotechnology, Vavilov Institute of General Genetics, Russian Academy of SciencesMoscow, Russia
| | - Yuri Panchin
- Institute for Information Transmission Problems, Russian Academy of SciencesMoscow, Russia.,Department of Mathematical Methods in Biology, Belozersky Institute, M.V. Lomonosov Moscow State UniversityMoscow, Russia
| | - Olga S Tarasova
- Institute for Information Transmission Problems, Russian Academy of SciencesMoscow, Russia.,Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State UniversityMoscow, Russia.,State Research Center of the Russian Federation, Institute for Biomedical Problems, Russian Academy of SciencesMoscow, Russia
| | - Dina Gaynullina
- Department of Human and Animal Physiology, Faculty of Biology, M.V. Lomonosov Moscow State UniversityMoscow, Russia.,Department of Physiology, Russian National Research Medical UniversityMoscow, Russia
| | - Vladimir M Kovalzon
- Institute for Information Transmission Problems, Russian Academy of SciencesMoscow, Russia.,Severtsov Institute Ecology and Evolution, Russian Academy of SciencesMoscow, Russia
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76
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Molica F, Stierlin FB, Fontana P, Kwak BR. Pannexin- and Connexin-Mediated Intercellular Communication in Platelet Function. Int J Mol Sci 2017; 18:E850. [PMID: 28420171 PMCID: PMC5412434 DOI: 10.3390/ijms18040850] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Revised: 04/06/2017] [Accepted: 04/12/2017] [Indexed: 12/11/2022] Open
Abstract
The three major blood cell types, i.e., platelets, erythrocytes and leukocytes, are all produced in the bone marrow. While red blood cells are the most numerous and white cells are the largest, platelets are small fragments and account for a minor part of blood volume. However, platelets display a crucial function by preventing bleeding. Upon vessel wall injury, platelets adhere to exposed extracellular matrix, become activated, and form a platelet plug preventing hemorrhagic events. However, when platelet activation is exacerbated, as in rupture of an atherosclerotic plaque, the same mechanism may lead to acute thrombosis causing major ischemic events such as myocardial infarction or stroke. In the past few years, major progress has been made in understanding of platelet function modulation. In this respect, membrane channels formed by connexins and/or pannexins are of particular interest. While it is still not completely understood whether connexins function as hemichannels or gap junction channels to inhibit platelet aggregation, there is clear-cut evidence for a specific implication of pannexin1 channels in collagen-induced aggregation. The focus of this review is to summarize current knowledge of the role of connexins and pannexins in platelet aggregation and to discuss possible pharmacological approaches along with their limitations and future perspectives for new potential therapies.
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Affiliation(s)
- Filippo Molica
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
| | - Florian B Stierlin
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
- Geneva Platelet Group, University of Geneva, 1211 Geneva, Switzerland.
| | - Pierre Fontana
- Geneva Platelet Group, University of Geneva, 1211 Geneva, Switzerland.
- Division of Angiology and Haemostasis, Geneva University Hospitals, 1211 Geneva, Switzerland.
| | - Brenda R Kwak
- Department of Pathology and Immunology, University of Geneva, 1211 Geneva, Switzerland.
- Department of Medical Specializations, Cardiology, University of Geneva, 1211 Geneva, Switzerland.
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77
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Boyce AKJ, Epp AL, Nagarajan A, Swayne LA. Transcriptional and post-translational regulation of pannexins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:72-82. [PMID: 28279657 DOI: 10.1016/j.bbamem.2017.03.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Revised: 03/02/2017] [Accepted: 03/03/2017] [Indexed: 12/21/2022]
Abstract
Pannexins are a 3-membered family of proteins that form large pore ion and metabolite channels in vertebrates. The impact of pannexins on vertebrate biology is intricately tied to where and when they are expressed, and how they are modified, once produced. The purpose of this review is therefore to outline our current understanding of transcriptional and post-translational regulation of pannexins. First, we briefly summarize their discovery and characteristics. Next, we describe several aspects of transcriptional regulation, including cell and tissue-specific expression, dynamic expression over development and disease, as well as new insights into the underlying molecular machinery involved. Following this, we delve into the role of post-translational modifications in the regulation of trafficking and channel properties, highlighting important work on glycosylation, phosphorylation, S-nitrosylation and proteolytic cleavage. Embedded throughout, we also highlight important knowledge gaps and avenues of future research. This article is part of a Special Issue entitled: Gap Junction Proteins edited by Jean Claude Herve.
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Affiliation(s)
- Andrew K J Boyce
- Division of Medical Sciences and Island Medical Program, University of Victoria, Victoria V8P 5C2, Canada
| | - Anna L Epp
- Division of Medical Sciences and Island Medical Program, University of Victoria, Victoria V8P 5C2, Canada
| | - Archana Nagarajan
- Division of Medical Sciences and Island Medical Program, University of Victoria, Victoria V8P 5C2, Canada
| | - Leigh Anne Swayne
- Division of Medical Sciences and Island Medical Program, University of Victoria, Victoria V8P 5C2, Canada; Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver V6T 1Z3, Canada.
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Weaver JL, Arandjelovic S, Brown G, K Mendu S, S Schappe M, Buckley MW, Chiu YH, Shu S, Kim JK, Chung J, Krupa J, Jevtovic-Todorovic V, Desai BN, Ravichandran KS, Bayliss DA. Hematopoietic pannexin 1 function is critical for neuropathic pain. Sci Rep 2017; 7:42550. [PMID: 28195232 PMCID: PMC5307344 DOI: 10.1038/srep42550] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 01/12/2017] [Indexed: 12/13/2022] Open
Abstract
Neuropathic pain symptoms respond poorly to available therapeutics, with most treated patients reporting unrelieved pain and significant impairment in daily life. Here, we show that Pannexin 1 (Panx1) in hematopoietic cells is required for pain-like responses following nerve injury in mice, and a potential therapeutic target. Panx1 knockout mice (Panx1-/-) were protected from hypersensitivity in two sciatic nerve injury models. Bone marrow transplantation studies show that expression of functional Panx1 in hematopoietic cells is necessary for mechanical hypersensitivity following nerve injury. Reconstitution of irradiated Panx1 knockout mice with hematopoietic Panx1-/- cells engineered to re-express Panx1 was sufficient to recover hypersensitivity after nerve injury; this rescue required expression of a Panx1 variant that can be activated by G protein-coupled receptors (GPCRs). Finally, chemically distinct Panx1 inhibitors blocked development of nerve injury-induced hypersensitivity and partially relieved this hypersensitivity after it was established. These studies indicate that Panx1 expressed in immune cells is critical for pain-like effects following nerve injury in mice, perhaps via a GPCR-mediated activation mechanism, and suggest that inhibition of Panx1 may be useful in treating neuropathic pain.
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Affiliation(s)
- Janelle L Weaver
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Sanja Arandjelovic
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Gregory Brown
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Suresh K Mendu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Michael S Schappe
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Monica W Buckley
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Yu-Hsin Chiu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Shaofang Shu
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Jin K Kim
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Joyce Chung
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Julia Krupa
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | | | - Bimal N Desai
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Kodi S Ravichandran
- Department of Microbiology, Immunology, Cancer Biology, University of Virginia, Charlottesville, Virginia 22908, USA.,Carter Immunology Center, University of Virginia, Charlottesville, Virginia 22908, USA.,Center for Cell Clearance, University of Virginia, Charlottesville, Virginia 22908, USA
| | - Douglas A Bayliss
- Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908, USA
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79
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Bol M, Wang N, De Bock M, Wacquier B, Decrock E, Gadicherla A, Decaluwé K, Vanheel B, van Rijen HVM, Krysko DV, Bultynck G, Dupont G, Van de Voorde J, Leybaert L. At the cross-point of connexins, calcium, and ATP: blocking hemichannels inhibits vasoconstriction of rat small mesenteric arteries. Cardiovasc Res 2017; 113:195-206. [PMID: 27677282 DOI: 10.1093/cvr/cvw215] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Revised: 09/22/2016] [Accepted: 09/25/2016] [Indexed: 02/07/2023] Open
Abstract
AIMS Connexins form gap-junctions (GJs) that directly connect cells, thereby coordinating vascular cell function and controlling vessel diameter and blood flow. GJs are composed of two hemichannels contributed by each of the connecting cells. Hemichannels also exist as non-junctional channels that, when open, lead to the entry/loss of ions and the escape of ATP. Here we investigated cross-talk between hemichannels and Ca2+/purinergic signalling in controlling blood vessel contraction. We hypothesized that hemichannel Ca2+ entry and ATP release contributes to smooth muscle cell (SMC) Ca2+ dynamics, thereby influencing vessel contractility. We applied several peptide modulators of hemichannel function and inhibitors of Ca2+ and ATP signalling to investigate their influence on SMC Ca2+ dynamics and vessel contractility. METHODS AND RESULTS Confocal Ca2+ imaging studies on small mesenteric arteries (SMAs) from rat demonstrated that norepinephrine-induced SMC Ca2+ oscillations were inhibited by blocking IP3 receptors with xestospongin-C and by interfering with hemichannel function, most notably by the specific Cx43 hemichannel blocking peptide TAT-L2 and by TAT-CT9 that promotes Cx43 hemichannel opening. Evidence for hemichannel involvement in SMC function was supported by the fact that TAT-CT9 significantly increased SMC resting cytoplasmic Ca2+ concentration, indicating it facilitated Ca2+ entry, and by the observation that norepinephrine-triggered vessel ATP release was blocked by TAT-L2. Myograph tension measurements on isolated SMAs showed significant inhibition of norepinephrine-triggered contractility by the ATP receptor antagonist suramin, but the strongest effect was observed with TAT-L2 that gave ∼80% inhibition at 37 °C. TAT-L2 inhibition of vessel contraction was significantly reduced in conditional Cx43 knockout animals, indicating the effect was Cx43 hemichannel-dependent. Computational modelling suggested these results could be explained by the opening of a single hemichannel per SMC. CONCLUSIONS These results indicate that Cx43 hemichannels contribute to SMC Ca2+ dynamics and contractility, by facilitating Ca2+ entry, ATP release, and purinergic signalling.
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MESH Headings
- Adenosine Triphosphate/metabolism
- Animals
- Calcium/metabolism
- Calcium Signaling/drug effects
- Cell Communication/drug effects
- Computer Simulation
- Connexin 43/antagonists & inhibitors
- Connexin 43/deficiency
- Connexin 43/genetics
- Connexin 43/metabolism
- Connexins/antagonists & inhibitors
- Connexins/metabolism
- Female
- Gap Junctions/drug effects
- Gap Junctions/metabolism
- Genotype
- In Vitro Techniques
- Inositol 1,4,5-Trisphosphate Receptors/agonists
- Inositol 1,4,5-Trisphosphate Receptors/metabolism
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/metabolism
- Mice, Knockout
- Microscopy, Confocal
- Models, Cardiovascular
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Norepinephrine/pharmacology
- Peptides/pharmacology
- Phenotype
- Purinergic Antagonists/pharmacology
- Rats, Wistar
- Time Factors
- Vasoconstriction/drug effects
- Vasoconstrictor Agents/pharmacology
- Vasodilator Agents/pharmacology
- Gap Junction alpha-4 Protein
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Affiliation(s)
- Mélissa Bol
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, De Pintelaan 185 (Block B, Room 031), 9000 Ghent, Belgium
| | - Nan Wang
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, De Pintelaan 185 (Block B, Room 031), 9000 Ghent, Belgium
| | - Marijke De Bock
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, De Pintelaan 185 (Block B, Room 031), 9000 Ghent, Belgium
| | - Benjamin Wacquier
- Unité de Chronobiologie Théorique, Faculté des Sciences, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
| | - Elke Decrock
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, De Pintelaan 185 (Block B, Room 031), 9000 Ghent, Belgium
| | - Ashish Gadicherla
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, De Pintelaan 185 (Block B, Room 031), 9000 Ghent, Belgium
| | - Kelly Decaluwé
- Department of Pharmacology, Vascular Research Unit, Faculty of Medicine & Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Bert Vanheel
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, De Pintelaan 185 (Block B, Room 031), 9000 Ghent, Belgium
| | - Harold Victor Maria van Rijen
- Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, 3508 GA Utrecht, The Netherlands
| | - Dmitri Vadim Krysko
- Molecular Signaling and Cell Death Unit, VIB Inflammation Research Center, 9000 Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, 9000 Ghent, Belgium
| | - Geert Bultynck
- Laboratory of Molecular and Cellular Signalling, Department of Cellular and Molecular Medicine, KULeuven, 3000 Leuven, Belgium
| | - Geneviève Dupont
- Unité de Chronobiologie Théorique, Faculté des Sciences, Université Libre de Bruxelles (ULB), 1000 Brussels, Belgium
| | - Johan Van de Voorde
- Department of Pharmacology, Vascular Research Unit, Faculty of Medicine & Health Sciences, Ghent University, 9000 Ghent, Belgium
| | - Luc Leybaert
- Department of Basic Medical Sciences, Physiology Group, Faculty of Medicine & Health Sciences, Ghent University, De Pintelaan 185 (Block B, Room 031), 9000 Ghent, Belgium;
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80
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A quantized mechanism for activation of pannexin channels. Nat Commun 2017; 8:14324. [PMID: 28134257 PMCID: PMC5290276 DOI: 10.1038/ncomms14324] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2016] [Accepted: 12/16/2016] [Indexed: 11/18/2022] Open
Abstract
Pannexin 1 (PANX1) subunits form oligomeric plasma membrane channels that mediate nucleotide release for purinergic signalling, which is involved in diverse physiological processes such as apoptosis, inflammation, blood pressure regulation, and cancer progression and metastasis. Here we explore the mechanistic basis for PANX1 activation by using wild type and engineered concatemeric channels. We find that PANX1 activation involves sequential stepwise sojourns through multiple discrete open states, each with unique channel gating and conductance properties that reflect contributions of the individual subunits of the hexamer. Progressive PANX1 channel opening is directly linked to permeation of ions and large molecules (ATP and fluorescent dyes) and occurs during both irreversible (caspase cleavage-mediated) and reversible (α1 adrenoceptor-mediated) forms of channel activation. This unique, quantized activation process enables fine tuning of PANX1 channel activity and may be a generalized regulatory mechanism for other related multimeric channels. Pannexins are oligomeric plasma membrane channels that allow permeation of ions and large molecules. Here the authors show that human Pannexin 1 activation is a multistep event, where modification of each monomer opens the channel to a unique conductance state and fine tunes its activity.
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81
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Begandt D, Good ME, Keller AS, DeLalio LJ, Rowley C, Isakson BE, Figueroa XF. Pannexin channel and connexin hemichannel expression in vascular function and inflammation. BMC Cell Biol 2017; 18:2. [PMID: 28124621 PMCID: PMC5267334 DOI: 10.1186/s12860-016-0119-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Control of blood flow distribution and tissue homeostasis depend on the tight regulation of and coordination between the microvascular network and circulating blood cells. Channels formed by connexins or pannexins that connect the intra- and extracellular compartments allow the release of paracrine signals, such as ATP and prostaglandins, and thus play a central role in achieving fine regulation and coordination of vascular function. This review focuses on vascular connexin hemichannels and pannexin channels. We review their expression pattern within the arterial and venous system with a special emphasis on how post-translational modifications by phosphorylation and S-nitrosylation of these channels modulate their function and contribute to vascular homeostasis. Furthermore, we highlight the contribution of these channels in smooth muscle cells and endothelial cells in the regulation of vasomotor tone as well as how these channels in endothelial cells regulate inflammatory responses such as during ischemic and hypoxic conditions. In addition, this review will touch on recent evidence implicating a role for these proteins in regulating red blood cell and platelet function.
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Affiliation(s)
- Daniela Begandt
- Robert M Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Miranda E Good
- Robert M Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Alex S Keller
- Robert M Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Leon J DeLalio
- Robert M Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Carol Rowley
- Robert M Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA
| | - Brant E Isakson
- Robert M Berne Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, VA, 22908, USA.,Department of Molecular Physiology and Biophysics, University of Virginia School of Medicine, Charlottesville, VA, USA
| | - Xavier F Figueroa
- Departamento de Fisiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile.
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82
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Matos R, Cordeiro JM, Coelho A, Ferreira S, Silva C, Igawa Y, Cruz F, Charrua A. Bladder pain induced by prolonged peripheral alpha 1A adrenoceptor stimulation involves the enhancement of transient receptor potential vanilloid 1 activity and an increase of urothelial adenosine triphosphate release. Acta Physiol (Oxf) 2016; 218:265-275. [PMID: 27370818 DOI: 10.1111/apha.12744] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/22/2016] [Accepted: 06/28/2016] [Indexed: 12/24/2022]
Abstract
AIM Pathophysiological mechanisms of chronic visceral pain (CVP) are unknown. This study explores the association between the sympathetic system and bladder nociceptors activity by testing the effect of a prolonged adrenergic stimulation on transient receptor potential vanilloid 1 (TRPV1) activity and on urothelial adenosine triphosphate (ATP) release. METHODS Female Wistar rats received saline, phenylephrine (PHE), PHE + silodosin, PHE + naftopidil or PHE + prazosin. TRPV1 knockout and wild-type mice received saline or PHE. Visceral pain behaviour tests were performed before and after treatment. Cystometry was performed, during saline and capsaicin infusion. Fos immunoreactivity was assessed in L6 spinal cord segment. Human urothelial ATP release induced by mechanical and thermal stimulation was evaluated. RESULTS Subcutaneous, but not intrathecal, PHE administration induced pain, which was reversed by silodosin, a selective alpha 1A adrenoceptor antagonist, but not by naftopidil, a relatively selective antagonist for alpha 1D adrenoceptor. Silodosin also reversed PHE-induced bladder hyperactivity and L6 spinal cord Fos expression. Thus, in subsequent experiments, only silodosin was used. Wild-type, but not TRPV1 knockout, mice exhibited phenylephrine-induced pain. Capsaicin induced a greater increase in voiding contractions in PHE-treated rats than in control animals, and silodosin reversed this effect. When treated with PHE, ATP release from human urothelial cells was enhanced either by mechanical stimulation or by lowering the thermal threshold of urothelial TRPV1, which becomes abnormally responsive at body temperature. CONCLUSION This study suggests that the activation of peripheral alpha 1A adrenoceptors induces CVP, probably through its interaction with TRPV1 and ATP release.
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Affiliation(s)
- R. Matos
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; University of Porto; Porto Portugal
- Department of Experimental Biology; Faculty of Medicine of University of Porto; Porto Portugal
| | - J. M. Cordeiro
- CIMAR/CIIMAR-Interdisciplinary Centre of Marine and Environmental Research; University of Porto; Porto Portugal
| | - A. Coelho
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; University of Porto; Porto Portugal
- Department of Experimental Biology; Faculty of Medicine of University of Porto; Porto Portugal
- Department of Renal, Urologic and Infectious diseases; Faculty of Medicine of University of Porto; Porto Portugal
| | - S. Ferreira
- Department of Experimental Biology; Faculty of Medicine of University of Porto; Porto Portugal
| | - C. Silva
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; University of Porto; Porto Portugal
- Department of Renal, Urologic and Infectious diseases; Faculty of Medicine of University of Porto; Porto Portugal
- Department of Urology; Hospital S. João; Porto Portugal
| | - Y. Igawa
- Department of Continence Medicine; The University of Tokyo Graduate School of Medicine; Tokyo Japan
| | - F. Cruz
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; University of Porto; Porto Portugal
- Department of Renal, Urologic and Infectious diseases; Faculty of Medicine of University of Porto; Porto Portugal
- Department of Urology; Hospital S. João; Porto Portugal
| | - A. Charrua
- i3S - Instituto de Investigação e Inovação em Saúde; Universidade do Porto; Porto Portugal
- IBMC - Instituto de Biologia Molecular e Celular; University of Porto; Porto Portugal
- Department of Experimental Biology; Faculty of Medicine of University of Porto; Porto Portugal
- Department of Renal, Urologic and Infectious diseases; Faculty of Medicine of University of Porto; Porto Portugal
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83
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Keller TCS, Butcher JT, Broseghini-Filho GB, Marziano C, DeLalio LJ, Rogers S, Ning B, Martin JN, Chechova S, Cabot M, Shu X, Best AK, Good ME, Simão Padilha A, Purdy M, Yeager M, Peirce SM, Hu S, Doctor A, Barrett E, Le TH, Columbus L, Isakson BE. Modulating Vascular Hemodynamics With an Alpha Globin Mimetic Peptide (HbαX). Hypertension 2016; 68:1494-1503. [PMID: 27802421 PMCID: PMC5159279 DOI: 10.1161/hypertensionaha.116.08171] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2016] [Revised: 07/22/2016] [Accepted: 10/04/2016] [Indexed: 02/07/2023]
Abstract
The ability of hemoglobin to scavenge the potent vasodilator nitric oxide (NO) in the blood has been well established as a mechanism of vascular tone homeostasis. In endothelial cells, the alpha chain of hemoglobin (hereafter, alpha globin) and endothelial NO synthase form a macromolecular complex, providing a sink for NO directly adjacent to the production source. We have developed an alpha globin mimetic peptide (named HbαX) that displaces endogenous alpha globin and increases bioavailable NO for vasodilation. Here we show that, in vivo, HbαX administration increases capillary oxygenation and blood flow in arterioles acutely and produces a sustained decrease in systolic blood pressure in normal and angiotensin II-induced hypertensive states. HbαX acts with high specificity and affinity to endothelial NO synthase, without toxicity to liver and kidney and no effect on p50 of O2 binding in red blood cells. In human vasculature, HbαX blunts vasoconstrictive response to cumulative doses of phenylephrine, a potent constricting agent. By binding to endothelial NO synthase and displacing endogenous alpha globin, HbαX modulates important metrics of vascular function, increasing vasodilation and flow in the resistance vasculature.
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Affiliation(s)
- T C Stevenson Keller
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Joshua T Butcher
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Gilson Brás Broseghini-Filho
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Corina Marziano
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Leon J DeLalio
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Stephen Rogers
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Bo Ning
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Jennifer N Martin
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Sylvia Chechova
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Maya Cabot
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Xiahong Shu
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Angela K Best
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Miranda E Good
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Alessandra Simão Padilha
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Michael Purdy
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Mark Yeager
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Shayn M Peirce
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Song Hu
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Allan Doctor
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Eugene Barrett
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Thu H Le
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Linda Columbus
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.)
| | - Brant E Isakson
- From the Department of Molecular Physiology and Biological Physics (T.C.S.K., C.M., M.C., M.P., M.Y., B.E.I.), Robert M. Berne Cardiovascular Research Center (T.C.S.K., J.T.B., G.B.B.-F., C.M., L.J.D., X.S., A.K.B., M.E.G., B.E.I.), Department of Pharmacology (L.J.D.), Division of Nephrology, Department of Medicine (S.C., T.H.L.), and Division of Endocrinology, Department of Medicine (E.B.), University of Virginia School of Medicine, Charlottesville; Department of Physiological Sciences, Federal University of Espirito Santa, Brazil (G.B.B.-F., A.S.P.); Departments of Pediatrics and Biochemistry, Washington University in Saint Louis, MO (S.R., A.D.); Department of Biomedical Engineering (B.N., S.M.P., S.H.) and Department of Chemistry (J.N.M., L.C.), University of Virginia, Charlottesville; and College of Pharmacy, Dalian Medical University, Dalian, China (X.S.).
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Esseltine JL, Laird DW. Next-Generation Connexin and Pannexin Cell Biology. Trends Cell Biol 2016; 26:944-955. [PMID: 27339936 DOI: 10.1016/j.tcb.2016.06.003] [Citation(s) in RCA: 93] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 06/02/2016] [Accepted: 06/06/2016] [Indexed: 01/17/2023]
Abstract
Connexins and pannexins are two families of large-pore channel forming proteins that are capable of passing small signaling molecules. While connexins serve the seminal task of direct gap junctional intercellular communication, pannexins are far less understood but function primarily as single membrane channels in autocrine and paracrine signaling. Advancements in connexin and pannexin biology in recent years has revealed that in addition to well-described classical functions at the plasma membrane, exciting new evidence suggests that connexins and pannexins participate in alternative pathways involving multiple intracellular compartments. Here we briefly highlight classical functions of connexins and pannexins but focus our attention mostly on the transformative findings that suggest that these channel-forming proteins may serve roles far beyond our current understandings.
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Affiliation(s)
- Jessica L Esseltine
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, The University of Western Ontario, London, ON, Canada.
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85
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Abstract
Communication among cells via direct cell-cell contact by connexin gap junctions, or between cell and extracellular environment via pannexin channels or connexin hemichannels, is a key factor in cell function and tissue homeostasis. Upon malignant transformation in different cancer types, the dysregulation of these connexin and pannexin channels and their effect in cellular communication, can either enhance or suppress tumorigenesis and metastasis. In this review, we will highlight the latest reports on the role of the well characterized connexin family and its ability to form gap junctions and hemichannels in cancer. We will also introduce the more recently discovered family of pannexin channels and our current knowledge about their involvement in cancer progression.
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Affiliation(s)
- Jean X Jiang
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, 78229, USA
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, University of Western Ontario, London, Ontario, N6A5C1, Canada.
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86
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Shao Q, Lindstrom K, Shi R, Kelly J, Schroeder A, Juusola J, Levine KL, Esseltine JL, Penuela S, Jackson MF, Laird DW. A Germline Variant in the PANX1 Gene Has Reduced Channel Function and Is Associated with Multisystem Dysfunction. J Biol Chem 2016; 291:12432-12443. [PMID: 27129271 DOI: 10.1074/jbc.m116.717934] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Indexed: 12/20/2022] Open
Abstract
Pannexin1 (PANX1) is probably best understood as an ATP release channel involved in paracrine signaling. Given its ubiquitous expression, PANX1 pathogenic variants would be expected to lead to disorders involving multiple organ systems. Using whole exome sequencing, we discovered the first patient with a homozygous PANX1 variant (c.650G→A) resulting in an arginine to histidine substitution at position 217 (p.Arg217His). The 17-year-old female has intellectual disability, sensorineural hearing loss requiring bilateral cochlear implants, skeletal defects, including kyphoscoliosis, and primary ovarian failure. Her consanguineous parents are each heterozygous for this variant but are not affected by the multiorgan syndromes noted in the proband. Expression of the p.Arg217His mutant in HeLa, N2A, HEK293T, and Ad293 cells revealed normal PANX1 glycosylation and cell surface trafficking. Dye uptake, ATP release, and electrophysiological measurements revealed p.Arg217His to be a loss-of-function variant. Co-expression of the mutant with wild-type PANX1 suggested the mutant was not dominant-negative to PANX1 channel function. Collectively, we demonstrate a PANX1 missense change associated with human disease in the first report of a "PANX1-related disorder."
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Affiliation(s)
- Qing Shao
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Kristin Lindstrom
- Division of Genetics and Metabolism, Phoenix Children's Hospital, Phoenix, Arizona 85016
| | - Ruoyang Shi
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba R3E 0Z3, Canada,; Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, Manitoba R3E 0Z3, Canada
| | - John Kelly
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Audrey Schroeder
- Division of Genetics, University of Rochester Medical Center, Rochester, New York 14642
| | | | | | - Jessica L Esseltine
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Silvia Penuela
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada
| | - Michael F Jackson
- Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba R3E 0Z3, Canada,; Kleysen Institute for Advanced Medicine, Health Sciences Centre, Winnipeg, Manitoba R3E 0Z3, Canada
| | - Dale W Laird
- Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario N6A 5C1, Canada.
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87
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Pan L, Tang J, Liu H, Cheng B. Sympathetic nerves: How do they affect angiogenesis, particularly during wound healing of soft tissues? Clin Hemorheol Microcirc 2016; 62:181-91. [PMID: 26484721 DOI: 10.3233/ch-152019] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Liangli Pan
- Southern Medical University, Guangzhou, China
- Department of Plastic Surgery, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, China
| | - Jianbing Tang
- Department of Plastic Surgery, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, China
| | - Hongwei Liu
- Department of Plastic Surgery, the First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Biao Cheng
- Southern Medical University, Guangzhou, China
- Department of Plastic Surgery, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, China
- Center of Wound Treatment, Guangzhou General Hospital of Guangzhou Military Command, Guangzhou, China
- The Key Laboratory of Trauma Treatment & Tissue Repair of Tropical Area, PLA, Guangzhou, China
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88
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Abstract
Pannexin channels are newly discovered ATP release channels expressed throughout the body. Pannexin 1 (Panx1) channels have become of great interest as they appear to participate in a multitude of signalling cascades, including regulation of vascular function. Although numerous Panx1 pharmacological inhibitors have been discovered, these inhibitors are not specific for Panx1 and have additional effects on other proteins. Therefore, molecular tools, such as RNA interference and knockout animals, are needed to demonstrate the role of pannexins in various cellular functions. This review focuses on the known roles of Panx1 related to purinergic signalling in the vasculature focusing on post-translational modifications and channel gating mechanisms that may participate in the regulated release of ATP.
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89
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Do not let death do us part: 'find-me' signals in communication between dying cells and the phagocytes. Cell Death Differ 2016; 23:979-89. [PMID: 26891690 DOI: 10.1038/cdd.2016.13] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 01/04/2016] [Accepted: 01/07/2016] [Indexed: 12/12/2022] Open
Abstract
The turnover and clearance of cells is an essential process that is part of many physiological and pathological processes. Improper or deficient clearance of apoptotic cells can lead to excessive inflammation and autoimmune disease. The steps involved in cell clearance include: migration of the phagocyte toward the proximity of the dying cells, specific recognition and internalization of the dying cell, and degradation of the corpse. The ability of phagocytes to recognize and react to dying cells to perform efficient and immunologically silent engulfment has been well-characterized in vitro and in vivo. However, how apoptotic cells themselves initiate the corpse removal and also influence the cells within the neighboring environment during clearance was less understood. Recent exciting observations suggest that apoptotic cells can attract phagocytes through the regulated release of 'find-me' signals. More recent studies also suggest that these find-me signals can have additional roles outside of phagocyte attraction to help orchestrate engulfment. This review will discuss our current understanding of the different find-me signals released by apoptotic cells, how they may be relevant in vivo, and their additional roles in facilitating engulfment.
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90
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Marsh A, Casey-Green K, Probert F, Withall D, Mitchell DA, Dilly SJ, James S, Dimitri W, Ladwa SR, Taylor PC, Singer DRJ. Simvastatin Sodium Salt and Fluvastatin Interact with Human Gap Junction Gamma-3 Protein. PLoS One 2016; 11:e0148266. [PMID: 26863535 PMCID: PMC4749215 DOI: 10.1371/journal.pone.0148266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Accepted: 01/15/2016] [Indexed: 11/26/2022] Open
Abstract
Finding pleiomorphic targets for drugs allows new indications or warnings for treatment to be identified. As test of concept, we applied a new chemical genomics approach to uncover additional targets for the widely prescribed lipid-lowering pro-drug simvastatin. We used mRNA extracted from internal mammary artery from patients undergoing coronary artery surgery to prepare a viral cardiovascular protein library, using T7 bacteriophage. We then studied interactions of clones of the bacteriophage, each expressing a different cardiovascular polypeptide, with surface-bound simvastatin in 96-well plates. To maximise likelihood of identifying meaningful interactions between simvastatin and vascular peptides, we used a validated photo-immobilisation method to apply a series of different chemical linkers to bind simvastatin so as to present multiple orientations of its constituent components to potential targets. Three rounds of biopanning identified consistent interaction with the clone expressing part of the gene GJC3, which maps to Homo sapiens chromosome 7, and codes for gap junction gamma-3 protein, also known as connexin 30.2/31.3 (mouse connexin Cx29). Further analysis indicated the binding site to be for the N-terminal domain putatively 'regulating' connexin hemichannel and gap junction pores. Using immunohistochemistry we found connexin 30.2/31.3 to be present in samples of artery similar to those used to prepare the bacteriophage library. Surface plasmon resonance revealed that a 25 amino acid synthetic peptide representing the discovered N-terminus did not interact with simvastatin lactone, but did bind to the hydrolysed HMG CoA inhibitor, simvastatin acid. This interaction was also seen for fluvastatin. The gap junction blockers carbenoxolone and flufenamic acid also interacted with the same peptide providing insight into potential site of binding. These findings raise key questions about the functional significance of GJC3 transcripts in the vasculature and other tissues, and this connexin's role in therapeutic and adverse effects of statins in a range of disease states.
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Affiliation(s)
- Andrew Marsh
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | | | - Fay Probert
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - David Withall
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Daniel A. Mitchell
- Division of Metabolic and Vascular Health, Clinical Sciences Research Laboratories, Warwick Medical School, University of Warwick, Coventry, CV2 2DX, United Kingdom
| | - Suzanne J. Dilly
- Tangent Reprofiling Ltd, c/o SEEK, Central Point, 45 Beech Street, London, EC2Y 8AD, United Kingdom
| | - Sean James
- University Hospital Coventry and Warwickshire, Clifford Bridge Road, Coventry CV2 2DX, United Kingdom
| | - Wade Dimitri
- University Hospital Coventry and Warwickshire, Clifford Bridge Road, Coventry CV2 2DX, United Kingdom
| | - Sweta R. Ladwa
- Tangent Reprofiling Ltd, c/o SEEK, Central Point, 45 Beech Street, London, EC2Y 8AD, United Kingdom
| | - Paul C. Taylor
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, United Kingdom
| | - Donald R. J. Singer
- University Hospital Coventry and Warwickshire, Clifford Bridge Road, Coventry CV2 2DX, United Kingdom
- Fellowship of Postgraduate Medicine, 11 Chandos St, London W1G 9EB, United Kingdom
- Division of Metabolic and Vascular Health, Clinical Sciences Research Laboratories, Warwick Medical School, University of Warwick, Coventry, CV2 2DX, United Kingdom
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91
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Michalski K, Kawate T. Carbenoxolone inhibits Pannexin1 channels through interactions in the first extracellular loop. ACTA ACUST UNITED AC 2016; 147:165-74. [PMID: 26755773 PMCID: PMC4727946 DOI: 10.1085/jgp.201511505] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/18/2015] [Indexed: 12/15/2022]
Abstract
A chimeric approach combined with extensive site-directed mutagenesis reveals new information about the interaction of the toxin carbenoxolone with the ATP release channel Pannexin1 and the role of the first extracellular loop in channel gating. Pannexin1 (Panx1) is an ATP release channel important for controlling immune responses and synaptic strength. Various stimuli including C-terminal cleavage, a high concentration of extracellular potassium, and voltage have been demonstrated to activate Panx1. However, it remains unclear how Panx1 senses and integrates such diverse stimuli to form an open channel. To provide a clue on the mechanism underlying Panx1 channel gating, we investigated the action mechanism of carbenoxolone (CBX), the most commonly used small molecule for attenuating Panx1 function triggered by a wide range of stimuli. Using a chimeric approach, we discovered that CBX reverses its action polarity and potentiates the voltage-gated channel activity of Panx1 when W74 in the first extracellular loop is mutated to a nonaromatic residue. A systematic mutagenesis study revealed that conserved residues in this loop also play important roles in CBX function, potentially by mediating CBX binding. We extended our experiments to other Panx1 inhibitors such as probenecid and ATP, which also potentiate the voltage-gated channel activity of a Panx1 mutant at position 74. Notably, probenecid alone can activate this mutant at a resting membrane potential. These data suggest that CBX and other inhibitors, including probenecid, attenuate Panx1 channel activity through modulation of the first extracellular loop. Our experiments are the first step toward identifying a previously unknown mode of CBX action, which provide insight into the role of the first extracellular loop in Panx1 channel gating.
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Affiliation(s)
- Kevin Michalski
- Department of Molecular Medicine, Field of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, NY 14853
| | - Toshimitsu Kawate
- Department of Molecular Medicine, Field of Biochemistry, Molecular, and Cell Biology, Cornell University, Ithaca, NY 14853
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92
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Angus JA, Wright CE. ATP is not involved in α1-adrenoceptor-mediated vasoconstriction in resistance arteries. Eur J Pharmacol 2015; 769:162-6. [PMID: 26593428 DOI: 10.1016/j.ejphar.2015.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 10/12/2015] [Accepted: 11/12/2015] [Indexed: 12/13/2022]
Abstract
Recent publications suggest that α1-adrenoceptor stimulation by exogenous agonists such as phenylephrine in resistance arteries cause contraction through the release of ATP from within the vascular smooth muscle cells. This ATP exits the cell through pannexin-1 channels to act back "autocrine-like" on P2 receptors on the smooth muscle that cause the contraction. In this work we directly test this hypothesis by using a selective P2X1 purinoceptor antagonist NF449 (1-10µM) against phenylephrine and ATP concentration-response curves in small mesenteric arteries of the rat and thoracodorsal arteries of the mouse. We show that NF449 is a simple competitive antagonist of ATP with a pKB of 6.43 and 6.41 in rat and mouse arteries, respectively, but did not antagonise phenylephrine concentration-response curves. This work cautions against the growing overstated role of the reputed pannexin-1/ATP release axis following α1-adrenoceptor activation in small resistance arteries.
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Affiliation(s)
- James A Angus
- Cardiovascular Therapeutics Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Victoria 3010, Australia.
| | - Christine E Wright
- Cardiovascular Therapeutics Unit, Department of Pharmacology and Therapeutics, University of Melbourne, Victoria 3010, Australia.
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93
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Pannexin 1 channels regulate leukocyte emigration through the venous endothelium during acute inflammation. Nat Commun 2015; 6:7965. [PMID: 26242575 PMCID: PMC4824045 DOI: 10.1038/ncomms8965] [Citation(s) in RCA: 141] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 06/30/2015] [Indexed: 12/18/2022] Open
Abstract
Inflammatory cell recruitment to local sites of tissue injury and/or infection is controlled by a plethora of signalling processes influencing cell-to-cell interactions between the vascular endothelial cells (ECs) in post-capillary venules and circulating leukocytes. Recently, ATP-sensitive P2Y purinergic receptors have emerged as downstream regulators of EC activation in vascular inflammation. However, the mechanism(s) regulating cellular ATP release in this response remains elusive. Here we report that the ATP-release channel Pannexin1 (Panx1) opens downstream of EC activation by TNF-α. This process involves activation of type-1 TNF receptors, recruitment of Src family kinases (SFK) and SFK-dependent phosphorylation of Panx1. Using an inducible, EC-specific Panx1 knockout mouse line, we report a previously unidentified role for Panx1 channels in promoting leukocyte adhesion and emigration through the venous wall during acute systemic inflammation, placing Panx1 channels at the centre of cytokine crosstalk with purinergic signalling in the endothelium. Endothelial cell activation by inflammation requires extracellular ATP release. Here the authors show that TNF-α induces Src-family kinase-dependent ATP release by Pannexin1 channels in endothelial cells, and that Pannexin1 is required for leukocyte adhesion and emigration into the inflamed tissue.
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94
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Meens MJ, Kwak BR, Duffy HS. Role of connexins and pannexins in cardiovascular physiology. Cell Mol Life Sci 2015; 72:2779-92. [PMID: 26091747 PMCID: PMC11113959 DOI: 10.1007/s00018-015-1959-2] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 06/11/2015] [Indexed: 12/26/2022]
Abstract
Connexins and pannexins form connexons, pannexons and membrane channels, which are critically involved in many aspects of cardiovascular physiology. For that reason, a vast number of studies have addressed the role of connexins and pannexins in the arterial and venous systems as well as in the heart. Moreover, a role for connexins in lymphatics has recently also been suggested. This review provides an overview of the current knowledge regarding the involvement of connexins and pannexins in cardiovascular physiology.
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Affiliation(s)
- Merlijn J. Meens
- Department of Pathology and Immunology, University of Geneva, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
- Department of Medical Specializations-Cardiology, University of Geneva, Geneva, Switzerland
| | - Brenda R. Kwak
- Department of Pathology and Immunology, University of Geneva, Rue Michel-Servet 1, 1211 Geneva 4, Switzerland
- Department of Medical Specializations-Cardiology, University of Geneva, Geneva, Switzerland
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95
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Pannexin 1 is required for full activation of insulin-stimulated glucose uptake in adipocytes. Mol Metab 2015; 4:610-8. [PMID: 26413467 PMCID: PMC4563021 DOI: 10.1016/j.molmet.2015.06.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2015] [Accepted: 06/27/2015] [Indexed: 02/08/2023] Open
Abstract
Objective Defective glucose uptake in adipocytes leads to impaired metabolic homeostasis and insulin resistance, hallmarks of type 2 diabetes. Extracellular ATP-derived nucleotides and nucleosides are important regulators of adipocyte function, but the pathway for controlled ATP release from adipocytes is unknown. Here, we investigated whether Pannexin 1 (Panx1) channels control ATP release from adipocytes and contribute to metabolic homeostasis. Methods We assessed Panx1 functionality in cultured 3T3-L1 adipocytes and in adipocytes isolated from murine white adipose tissue by measuring ATP release in response to known activators of Panx1 channels. Glucose uptake in cultured 3T3-L1 adipocytes was measured in the presence of Panx1 pharmacologic inhibitors and in adipocytes isolated from white adipose tissue from wildtype (WT) or adipocyte-specific Panx1 knockout (AdipPanx1 KO) mice generated in our laboratory. We performed in vivo glucose uptake studies in chow fed WT and AdipPanx1 KO mice and assessed insulin resistance in WT and AdipPanx1 KO mice fed a high fat diet for 12 weeks. Panx1 channel function was assessed in response to insulin by performing electrophysiologic recordings in a heterologous expression system. Finally, we measured Panx1 mRNA in human visceral adipose tissue samples by qRT-PCR and compared expression levels with glucose levels and HOMA-IR measurements in patients. Results Our data show that adipocytes express functional Pannexin 1 (Panx1) channels that can be activated to release ATP. Pharmacologic inhibition or selective genetic deletion of Panx1 from adipocytes decreased insulin-induced glucose uptake in vitro and in vivo and exacerbated diet-induced insulin resistance in mice. Further, we identify insulin as a novel activator of Panx1 channels. In obese humans Panx1 expression in adipose tissue is increased and correlates with the degree of insulin resistance. Conclusions We show that Panx1 channel activity regulates insulin-stimulated glucose uptake in adipocytes and thus contributes to control of metabolic homeostasis. Adipocytes express Pannexin 1 channels that can be activated to release ATP. Inhibition of Pannexin 1 decreased insulin-induced glucose uptake in adipocytes. Adipocyte Pannexin 1 knockout mice are more insulin resistant on high fat diet. We identify insulin as a novel activator of Pannexin 1 channels. Pannexin 1 expression in human adipose tissue correlates with insulin resistance.
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96
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Abstract
Sympathetic vasoconstriction plays an important role in the control of blood pressure and the distribution of blood flow. In this issue of Science Signaling, Billaud et al. show that sympathetic vasoconstriction occurs through a complex scheme involving the activation of large-pore pannexin 1 channels and the subsequent release of adenosine triphosphate that promotes contraction in an autocrine and paracrine manner. This elaborate mechanism may function as a point of intercept for other signaling pathways—for example, in relation to the phenomenon "functional sympatholysis," in which exercise abrogates sympathetic vasoconstriction in skeletal muscle. Because pannexin 1 channels are inhibited by nitric oxide, they may function as a switch to turn off adrenergic signaling in skeletal muscle during exercise.
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Affiliation(s)
- Morten Schak Nielsen
- The Danish National Research Foundation Centre for Cardiac Arrhythmia and Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Denmark.
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