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Stransky N, Ganser K, Quintanilla-Martinez L, Gonzalez-Menendez I, Naumann U, Eckert F, Koch P, Huber SM, Ruth P. Efficacy of combined tumor irradiation and K Ca3.1-targeting with TRAM-34 in a syngeneic glioma mouse model. Sci Rep 2023; 13:20604. [PMID: 37996600 PMCID: PMC10667541 DOI: 10.1038/s41598-023-47552-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2023] [Accepted: 11/15/2023] [Indexed: 11/25/2023] Open
Abstract
The intermediate-conductance calcium-activated potassium channel KCa3.1 has been proposed to be a new potential target for glioblastoma treatment. This study analyzed the effect of combined irradiation and KCa3.1-targeting with TRAM-34 in the syngeneic, immune-competent orthotopic SMA-560/VM/Dk glioma mouse model. Whereas neither irradiation nor TRAM-34 treatment alone meaningfully prolonged the survival of the animals, the combination significantly prolonged the survival of the mice. We found an irradiation-induced hyperinvasion of glioma cells into the brain, which was inhibited by concomitant TRAM-34 treatment. Interestingly, TRAM-34 did neither radiosensitize nor impair SMA-560's intrinsic migratory capacities in vitro. Exploratory findings hint at increased TGF-β1 signaling after irradiation. On top, we found a marginal upregulation of MMP9 mRNA, which was inhibited by TRAM-34. Last, infiltration of CD3+, CD8+ or FoxP3+ T cells was not impacted by either irradiation or KCa3.1 targeting and we found no evidence of adverse events of the combined treatment. We conclude that concomitant irradiation and TRAM-34 treatment is efficacious in this preclinical glioma model.
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Affiliation(s)
- Nicolai Stransky
- Department of Radiation Oncology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, 72076, Tübingen, Germany
| | - Katrin Ganser
- Department of Radiation Oncology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
| | - Leticia Quintanilla-Martinez
- Institute of Pathology and Neuropathology, Comprehensive Cancer Center, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University, Tübingen, Germany
| | - Irene Gonzalez-Menendez
- Institute of Pathology and Neuropathology, Comprehensive Cancer Center, Eberhard Karls University of Tübingen, 72076, Tübingen, Germany
- Cluster of Excellence iFIT (EXC 2180) "Image-Guided and Functionally Instructed Tumor Therapies", Eberhard Karls University, Tübingen, Germany
| | - Ulrike Naumann
- Molecular Neurooncology, Hertie Institute for Clinical Brain Research and Center Neurology, University of Tübingen, 72076, Tübingen, Germany
- Faculty of Medicine University, Gene and RNA Therapy Center (GRTC), Tübingen, Germany
| | - Franziska Eckert
- Department of Radiation Oncology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany
- Department of Radiation Oncology, Comprehensive Cancer Center, Medical University Vienna, AKH, Wien, Austria
| | - Pierre Koch
- Department of Pharmaceutical/Medicinal Chemistry II, Institute of Pharmacy, University of Regensburg, 93040, Regensburg, Germany
| | - Stephan M Huber
- Department of Radiation Oncology, University of Tübingen, Hoppe-Seyler-Str. 3, 72076, Tübingen, Germany.
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical Pharmacy, Institute of Pharmacy, University of Tübingen, 72076, Tübingen, Germany
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2
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Orfali R, AlFaiz A, Rahman MA, Lau L, Nam YW, Zhang M. K Ca2 and K Ca3.1 Channels in the Airways: A New Therapeutic Target. Biomedicines 2023; 11:1780. [PMID: 37509419 PMCID: PMC10376499 DOI: 10.3390/biomedicines11071780] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 06/08/2023] [Accepted: 06/13/2023] [Indexed: 07/30/2023] Open
Abstract
K+ channels are involved in many critical functions in lung physiology. Recently, the family of Ca2+-activated K+ channels (KCa) has received more attention, and a massive amount of effort has been devoted to developing selective medications targeting these channels. Within the family of KCa channels, three small-conductance Ca2+-activated K+ (KCa2) channel subtypes, together with the intermediate-conductance KCa3.1 channel, are voltage-independent K+ channels, and they mediate Ca2+-induced membrane hyperpolarization. Many KCa2 channel members are involved in crucial roles in physiological and pathological systems throughout the body. In this article, different subtypes of KCa2 and KCa3.1 channels and their functions in respiratory diseases are discussed. Additionally, the pharmacology of the KCa2 and KCa3.1 channels and the link between these channels and respiratory ciliary regulations will be explained in more detail. In the future, specific modulators for small or intermediate Ca2+-activated K+ channels may offer a unique therapeutic opportunity to treat muco-obstructive lung diseases.
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Affiliation(s)
- Razan Orfali
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
- Biomedical Research Administration, Research Centre, King Fahad Medical City, Riyadh Second Health Cluster, Riyadh 12231, Saudi Arabia
| | - Ali AlFaiz
- Biomedical Research Administration, Research Centre, King Fahad Medical City, Riyadh Second Health Cluster, Riyadh 12231, Saudi Arabia
| | - Mohammad Asikur Rahman
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
| | - Liz Lau
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
| | - Young-Woo Nam
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
| | - Miao Zhang
- Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, Irvine, CA 92618, USA
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3
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Lew VL. The circulatory dynamics of human red blood cell homeostasis: Oxy-deoxy and PIEZO1-triggered changes. Biophys J 2023; 122:484-495. [PMID: 36588342 PMCID: PMC9941722 DOI: 10.1016/j.bpj.2022.12.038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/14/2022] [Accepted: 12/30/2022] [Indexed: 01/02/2023] Open
Abstract
The vital function of red blood cells (RBCs) is to mediate the transport of oxygen from lungs to tissues and of CO2 from tissues to lungs. The gas exchanges occur during capillary transits within fractions of a second. Each oxygenation-deoxygenation and deoxygenation-reoxygenation transition on hemoglobin triggers sharp changes in RBC pH, leading to downstream changes in ion fluxes, membrane potential, and cell volume. The dynamics of these changes during the variable periods between capillary transits in vivo remains a mystery inaccessible to study by current methodologies, a knowledge gap on a fundamental physiological process that is the focus of the present study. The use of a computational model of human RBC homeostasis of tested accreditation enabled a detailed investigation of the expected RBC changes during intercapillary transits, with results advancing novel insights and predictions. The predicted rates of relative RBC volume change on oxygenation-deoxygenation (oxy-deoxy) and deoxygenation-reoxygenation transitions were about 1.5%/min and -0.9%/min, respectively, far too slow to allow the cells to reach steady states in the intervals between capillary transits. The amplitude of the oxy-deoxy-reoxygenation volume fluctuations varied in proportion with the duration of the intercapillary transit intervals. Upon capillary entry, oxy-deoxy-induced changes occur concurrently with deformation-induced PIEZO1 channel activation, both processes affecting cell pH, membrane potential, and cell volume during intertransit periods. The model showed that the effects were strictly additive as expected from processes operating independently on the cell's homeostatic fabric. Analysis of the mechanisms behind these predictions revealed, for the first time, the complex interactions between oxy-deoxy and ion transport processes that ensure the long-term homeostatic stability of RBCs for optimal gas transport in physiological conditions and how these may become altered in diseased states. Possible designs of microfluidic devices to test the model predictions are discussed.
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Affiliation(s)
- Virgilio L Lew
- Physiological Laboratory, Department of Physiology, Development and Neuroscience, University of Cambridge, Downing Site, Cambridge, United Kingdom.
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4
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Yan P, Ke B, Fang X. Ion channels as a therapeutic target for renal fibrosis. Front Physiol 2022; 13:1019028. [PMID: 36277193 PMCID: PMC9581181 DOI: 10.3389/fphys.2022.1019028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 09/20/2022] [Indexed: 11/13/2022] Open
Abstract
Renal ion channel transport and electrolyte disturbances play an important role in the process of functional impairment and fibrosis in the kidney. It is well known that there are limited effective drugs for the treatment of renal fibrosis, and since a large number of ion channels are involved in the renal fibrosis process, understanding the mechanisms of ion channel transport and the complex network of signaling cascades between them is essential to identify potential therapeutic approaches to slow down renal fibrosis. This review summarizes the current work of ion channels in renal fibrosis. We pay close attention to the effect of cystic fibrosis transmembrane conductance regulator (CFTR), transmembrane Member 16A (TMEM16A) and other Cl− channel mediated signaling pathways and ion concentrations on fibrosis, as well as the various complex mechanisms for the action of Ca2+ handling channels including Ca2+-release-activated Ca2+ channel (CRAC), purinergic receptor, and transient receptor potential (TRP) channels. Furthermore, we also focus on the contribution of Na+ transport such as epithelial sodium channel (ENaC), Na+, K+-ATPase, Na+-H+ exchangers, and K+ channels like Ca2+-activated K+ channels, voltage-dependent K+ channel, ATP-sensitive K+ channels on renal fibrosis. Proposed potential therapeutic approaches through further dissection of these mechanisms may provide new therapeutic opportunities to reduce the burden of chronic kidney disease.
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5
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Rivera A, Nasburg JA, Shim H, Shmukler BE, Kitten J, Wohlgemuth JG, Dlott JS, Snyder LM, Brugnara C, Wulff H, Alper SL. The erythroid K-Cl cotransport inhibitor [(dihydroindenyl)oxy]acetic acid blocks erythroid Ca 2+-activated K + channel KCNN4. Am J Physiol Cell Physiol 2022; 323:C694-C705. [PMID: 35848620 PMCID: PMC9448282 DOI: 10.1152/ajpcell.00240.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/22/2022]
Abstract
Red cell volume is a major determinant of HbS concentration in sickle cell disease. Cellular deoxy-HbS concentration determines the delay time, the interval between HbS deoxygenation and deoxy-HbS polymerization. Major membrane transporter protein determinants of sickle red cell volume include the SLC12/KCC K-Cl cotransporters KCC3/SLC12A6 and KCC1/SLC12A4, and the KCNN4/KCa3.1 Ca2+-activated K+ channel (Gardos channel). Among standard inhibitors of KCC-mediated K-Cl cotransport, only [(dihydroindenyl)oxy]acetic acid (DIOA) has been reported to lack inhibitory activity against the related bumetanide-sensitive erythroid Na-K-2Cl cotransporter NKCC1/SLC12A2. DIOA has been often used to inhibit K-Cl cotransport when studying the expression and regulation of other K+ transporters and K+ channels. We report here that DIOA at concentrations routinely used to inhibit K-Cl cotransport can also abrogate activity of the KCNN4/KCa3.1 Gardos channel in human and mouse red cells and in human sickle red cells. DIOA inhibition of A23187-stimulated erythroid K+ uptake (Gardos channel activity) was chloride-independent and persisted in mouse red cells genetically devoid of the principal K-Cl cotransporters KCC3 and KCC1. DIOA also inhibited YODA1-stimulated, chloride-independent erythroid K+ uptake. In contrast, DIOA exhibited no inhibitory effect on K+ influx into A23187-treated red cells of Kcnn4-/- mice. DIOA inhibition of human KCa3.1 was validated (IC50 42 µM) by whole cell patch clamp in HEK-293 cells. RosettaLigand docking experiments identified a potential binding site for DIOA in the fenestration region of human KCa3.1. We conclude that DIOA at concentrations routinely used to inhibit K-Cl cotransport can also block the KCNN4/KCa3.1 Gardos channel in normal and sickle red cells.
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Affiliation(s)
- Alicia Rivera
- Division of Nephrology and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | - Joshua A Nasburg
- Department of Pharmacology, School of Medicine, University of California, Davis, California
| | - Heesung Shim
- Department of Pharmacology, School of Medicine, University of California, Davis, California
| | - Boris E Shmukler
- Division of Nephrology and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
| | | | | | | | | | - Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Boston, Massachusetts
- Department of Pathology, Harvard Medical School, Boston, Massachusetts
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, California
| | - Seth L Alper
- Division of Nephrology and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, Massachusetts
- Department of Medicine, Harvard Medical School, Boston, Massachusetts
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6
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Laska MJ, Møller JB, Graversen JH, Strøbæk D, Blomster L, Christophersen P, Bahrami S. Retroviral glycoprotein-mediated immune suppression via the potassium channel KCa3.1 - A new strategy for amelioration of inflammatory bowel diseases. Clin Immunol 2022; 242:109081. [PMID: 35905828 DOI: 10.1016/j.clim.2022.109081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 07/01/2022] [Accepted: 07/20/2022] [Indexed: 11/03/2022]
Abstract
Peptides derived from retroviral envelope proteins have been shown to possess a wide range of immunosuppressive and anti-inflammatory activities. We have previously reported identification of such a peptide derived from the envelope protein coded by a human endogenous retrovirus (HERV). In this study, we identified that in vitro the peptide inhibits the KCa3.1 potassium channel, a potential target for therapy of immune diseases. We describe in vitro ENV59-GP3 effects with respect to potency of inhibition on KCa3.1 channels and calcium influx. Furthermore, we asses in vivo the effect of blocking KCa3.1 with ENV59-GP3 peptide or KCa3.1-blocker NS6180 on protection against DSS-induced acute colitis. ENV59-GP3 peptide treatment showed reduction of the disease score in the DSS-induced acute colitis mice model, which was comparable to effects of the KCa3.1 channel blocker NS6180. Analysis of cytokine production from DSS-mice model treated animals revealed equipotent inhibitory effects of the ENV59-GP3 and NS6180 compounds on the production of IL-6, TNF-α, IL-1β. These findings altogether suggest that ENV59-GP3 functions as a KCa3.1 channel inhibitor and underline the implications of using virus derived channel blockers for treatment of autoimmune diseases. Additionally, they open the possibilities whether KCa3.1 inhibition is efficacious in patients with inflammatory bowel diseases.
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Affiliation(s)
- Magdalena J Laska
- Department of Molecular Biology and Genetics, Aarhus University, Denmark.
| | - Jesper Bonnet Møller
- Department of Cancer and Inflammation Research, University of Southern Denmark, Denmark
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7
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Philp AR, Miranda F, Gianotti A, Mansilla A, Scudieri P, Musante I, Vega G, Figueroa CD, Galietta LJV, Sarmiento JM, Flores CA. KCa3.1 differentially regulates trachea and bronchi epithelial gene expression in a chronic-asthma mouse model. Physiol Genomics 2022; 54:273-282. [PMID: 35658672 DOI: 10.1152/physiolgenomics.00134.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Ion channels are potentially exploitable as pharmacological targets to treat asthma. This study evaluated the role of KCa3.1 channels, encoded by Kcnn4, in regulating the gene expression of mouse airway epithelium and the development of asthma traits. We used the ovalbumin (OVA) challenge as an asthma model in wild type and Kcnn4-/- mice, performed histological analysis, and measured serum IgE to evaluate asthma traits. We analyzed gene expression of isolated epithelial cells of trachea or bronchi using mRNA sequencing and gene ontology and performed Ussing chamber experiments in mouse trachea to evaluate anion secretion. Gene expression of epithelial cells from mouse airways differed between trachea and bronchi, indicating regional differences in the inflammatory and transepithelial transport properties of proximal and distal airways. We found that Kcnn4 silencing reduced mast cell numbers, mucus, and collagen in the airways, and reduced the amount of epithelial anion secretion in the OVA-challenged animals. Additionally, gene expression was differentially modified in the trachea and bronchi, with Kcnn4 genetic silencing significantly altering the expression of genes involved in the TNF pathway, supporting the potential of KCa3.1 as a therapeutic target for asthma.
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Affiliation(s)
- Amber R Philp
- Centro de Estudios Científicos, Valdivia, Los Rios, Chile.,Austral University of Chile, Valdivia, Chile
| | - Fernando Miranda
- Departamento de Fisiología, Austral University of Chile, Valdivia, Chile
| | | | - Agustín Mansilla
- Centro de Estudios Científicos, Valdivia, Los Rios, Chile.,Austral University of Chile, Valdivia, Chile
| | | | | | - Génesis Vega
- Centro de Estudios Científicos, Valdivia, Los Rios, Chile
| | | | - Luis J V Galietta
- TIGEM, Pozzuoli, Italia.,Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - José M Sarmiento
- Departamento de Fisiología, Austral University of Chile, Valdivia, Chile
| | - Carlos A Flores
- Centro de Estudios Científicos, Valdivia, Los Rios, Chile.,Universidad San Sebastián, Valdivia, Chile
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8
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Chibly AM, Aure MH, Patel VN, Hoffman MP. Salivary Gland Function, Development and Regeneration. Physiol Rev 2022; 102:1495-1552. [PMID: 35343828 DOI: 10.1152/physrev.00015.2021] [Citation(s) in RCA: 35] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Salivary glands produce and secrete saliva, which is essential for maintaining oral health and overall health. Understanding both the unique structure and physiological function of salivary glands, as well as how they are affected by disease and injury will direct the development of therapy to repair and regenerate them. Significant recent advances, particularly in the OMICS field, increase our understanding of how salivary glands develop at the cellular, molecular and genetic levels; the signaling pathways involved, the dynamics of progenitor cell lineages in development, homeostasis and regeneration and the role of the extracellular matrix microenvironment. These provide a template for cell and gene therapies as well as bioengineering approaches to repair or regenerate salivary function.
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Affiliation(s)
- Alejandro Martinez Chibly
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
| | - Marit H Aure
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
| | - Vaishali N Patel
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
| | - Matthew Philip Hoffman
- Matrix and Morphogenesis Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
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9
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Fuchs AA, Balne PK, Giuliano EA, Sinha NR, Mohan RR. Evaluation of a novel combination of TRAM-34 and ascorbic acid for the treatment of corneal fibrosis in vivo. PLoS One 2022; 17:e0262046. [PMID: 35007294 PMCID: PMC8746773 DOI: 10.1371/journal.pone.0262046] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 12/15/2021] [Indexed: 01/05/2023] Open
Abstract
Corneal injury and aberrant wound healing commonly result in corneal fibrosis and subsequent vision loss. Intermediate-conductance calmodulin/calcium-activated K+ channels (KCa3.1) have been shown to promote fibrosis in non-ocular and ocular tissues via upregulation of transforming growth factor beta (TGFβ). TRAM-34 is a selective inhibitor of KCa3.1 and reduces fibrosis by downregulation of TGFβ-induced transdifferentiation of stromal fibroblasts to myofibroblasts. Ascorbic acid has been demonstrated to be effective in promoting corneal re-epithelialization and reduction of neovascularization via anti-VEGF and anti-MMP mechanisms. This study evaluates tolerability and efficacy of a novel combination of TRAM-34 (25μM) and ascorbic acid (10%) topical treatment for corneal fibrosis using an established in vivo rabbit model and conducting clinical eye examinations. Markers of corneal fibrosis were evaluated in all corneas at study endpoint via histopathology, immunofluorescence, and quantitative real-time PCR. The eyedrop treated eyes showed significantly improved clinical outcomes based on modified McDonald Shadduck scores, reduction of clinical haze on Fantes scores, and reduction of central corneal thickness (CCT). At cellular and molecular levels, eyedrop treatment also significantly reduced expression of alpha smooth muscle actin (α-SMA) mRNA and protein, collagen III mRNA, and fibronectin mRNA compared to non-treated eyes. Our study suggests that a tested new bimodal eyedrop is well tolerated and effectively reduces corneal fibrosis/haze in rabbits in vivo.
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Affiliation(s)
- Allison A. Fuchs
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Praveen K. Balne
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States of America
| | - Elizabeth A. Giuliano
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Nishant R. Sinha
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States of America
| | - Rajiv R. Mohan
- Departments of Veterinary Medicine and Surgery and Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- Harry S. Truman Memorial Veterans Hospital, Columbia, Missouri, United States of America
- Mason Eye Institute, School of Medicine, University of Missouri, Columbia, Missouri, United States of America
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10
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Seo CH, Cui HS, Kim JB. Altered K Ca3.1 expression following burn injury and the therapeutic potential of TRAM-34 in post-burn hypertrophic scar formation. Transl Res 2021; 236:133-146. [PMID: 33905948 DOI: 10.1016/j.trsl.2021.04.007] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Revised: 04/09/2021] [Accepted: 04/18/2021] [Indexed: 01/16/2023]
Abstract
Hypertrophic scars are the most common post-burn complications characterized by fibroblast proliferation and excessive extracellular matrix deposition. The intermediate-conductance Ca2+-activated K+ channel (KCa3.1) mediates fibroblast activation, resulting in several fibrotic diseases; however, this channel's role in the formation of post-burn hypertrophic skin scars remains unknown. Herein, we investigated the role of KCa3.1 and the therapeutic potential of TRAM-34, a selective inhibitor of KCa3.1, in hypertrophic skin scar formation following burn injury. Cytosolic Ca2+ levels, the expression of KCa3.1 and hypertrophic markers, and the proliferation of skin fibroblasts obtained directly from patients with third-degree burns who consequently developed post-burn hypertrophic scars were assessed. The anti-fibrotic effect of KCa3.1 inhibition by TRAM-34 was evaluated in vitro (fibroblasts) and in vivo (mouse burn models). Fibroblasts from burn wounds exhibited remarkably higher levels of cytosolic Ca2+ than normal cells. KCa3.1 expression was markedly higher in the membrane fraction but lower in the cytosolic fraction of burn wound fibroblasts than in normal cells. Selective inhibition of KCa3.1 by TRAM-34 markedly reduced not only the proliferation of burn wound fibroblasts but also the expression of hypertrophic markers in these cells. Anti-scarring molecular, histological, and visual effects of TRAM-34 were confirmed in murine burn models. Altered subcellular expression of KCa3.1 is a novel mechanism underlying the cellular response to burn injury. Our results suggest that selective inhibition of KCa3.1 by TRAM-34 has therapeutic potential against post-burn hypertrophic scar formation.
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Affiliation(s)
- Cheong Hoon Seo
- Department of Rehabilitation Medicine, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - Hui Song Cui
- Burn Institute, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea
| | - June-Bum Kim
- Department of Pediatrics, Hangang Sacred Heart Hospital, Hallym University College of Medicine, Seoul, Republic of Korea.
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11
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Therapeutic Antibodies Targeting Potassium Ion Channels. Handb Exp Pharmacol 2021; 267:507-545. [PMID: 33963460 DOI: 10.1007/164_2021_464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Monoclonal antibodies combine specificity and high affinity binding with excellent pharmacokinetic properties and are rapidly being developed for a wide range of drug targets including clinically important potassium ion channels. Nonetheless, while therapeutic antibodies come with great promise, K+ channels represent particularly difficult targets for biologics development for a variety of reasons that include their dynamic structures and relatively small extracellular loops, their high degree of sequence conservation (leading to immune tolerance), and their generally low-level expression in vivo. The process is made all the more difficult when large numbers of antibody candidates must be screened for a given target, or when lead candidates fail to cross-react with orthologous channels in animal disease models due to their highly selective binding properties. While the number of antibodies targeting potassium channels in preclinical or clinical development is still modest, significant advances in the areas of protein expression and antibody screening are converging to open the field to an avalanche of new drugs. Here, the opportunities and constraints associated with the discovery of antibodies against K+ channels are discussed, with an emphasis on novel technologies that are opening the field to exciting new possibilities for biologics development.
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12
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Šterk M, Križančić Bombek L, Skelin Klemen M, Slak Rupnik M, Marhl M, Stožer A, Gosak M. NMDA receptor inhibition increases, synchronizes, and stabilizes the collective pancreatic beta cell activity: Insights through multilayer network analysis. PLoS Comput Biol 2021; 17:e1009002. [PMID: 33974632 PMCID: PMC8139480 DOI: 10.1371/journal.pcbi.1009002] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 05/21/2021] [Accepted: 04/26/2021] [Indexed: 12/15/2022] Open
Abstract
NMDA receptors promote repolarization in pancreatic beta cells and thereby reduce glucose-stimulated insulin secretion. Therefore, NMDA receptors are a potential therapeutic target for diabetes. While the mechanism of NMDA receptor inhibition in beta cells is rather well understood at the molecular level, its possible effects on the collective cellular activity have not been addressed to date, even though proper insulin secretion patterns result from well-synchronized beta cell behavior. The latter is enabled by strong intercellular connectivity, which governs propagating calcium waves across the islets and makes the heterogeneous beta cell population work in synchrony. Since a disrupted collective activity is an important and possibly early contributor to impaired insulin secretion and glucose intolerance, it is of utmost importance to understand possible effects of NMDA receptor inhibition on beta cell functional connectivity. To address this issue, we combined confocal functional multicellular calcium imaging in mouse tissue slices with network science approaches. Our results revealed that NMDA receptor inhibition increases, synchronizes, and stabilizes beta cell activity without affecting the velocity or size of calcium waves. To explore intercellular interactions more precisely, we made use of the multilayer network formalism by regarding each calcium wave as an individual network layer, with weighted directed connections portraying the intercellular propagation. NMDA receptor inhibition stabilized both the role of wave initiators and the course of waves. The findings obtained with the experimental antagonist of NMDA receptors, MK-801, were additionally validated with dextrorphan, the active metabolite of the approved drug dextromethorphan, as well as with experiments on NMDA receptor KO mice. In sum, our results provide additional and new evidence for a possible role of NMDA receptor inhibition in treatment of type 2 diabetes and introduce the multilayer network paradigm as a general strategy to examine effects of drugs on connectivity in multicellular systems.
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Affiliation(s)
- Marko Šterk
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | | | | | - Marjan Slak Rupnik
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Alma Mater Europaea–ECM, Maribor, Slovenia
| | - Marko Marhl
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Education, University of Maribor, Maribor, Slovenia
| | - Andraž Stožer
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Marko Gosak
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
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13
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14
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Vega G, Guequén A, Philp AR, Gianotti A, Arzola L, Villalón M, Zegarra-Moran O, Galietta LJ, Mall MA, Flores CA. Lack of Kcnn4 improves mucociliary clearance in muco-obstructive lung disease. JCI Insight 2020; 5:140076. [PMID: 32814712 PMCID: PMC7455130 DOI: 10.1172/jci.insight.140076] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 07/08/2020] [Indexed: 12/11/2022] Open
Abstract
Airway mucociliary clearance (MCC) is the main mechanism of lung defense keeping airways free of infection and mucus obstruction. Airway surface liquid volume, ciliary beating, and mucus are central for proper MCC and critically regulated by sodium absorption and anion secretion. Impaired MCC is a key feature of muco-obstructive diseases. The calcium-activated potassium channel KCa.3.1, encoded by Kcnn4, participates in ion secretion, and studies showed that its activation increases Na+ absorption in airway epithelia, suggesting that KCa3.1-induced hyperpolarization was sufficient to drive Na+ absorption. However, its role in airway epithelium is not fully understood. We aimed to elucidate the role of KCa3.1 in MCC using a genetically engineered mouse. KCa3.1 inhibition reduced Na+ absorption in mouse and human airway epithelium. Furthermore, the genetic deletion of Kcnn4 enhanced cilia beating frequency and MCC ex vivo and in vivo. Kcnn4 silencing in the Scnn1b-transgenic mouse (Scnn1btg/+), a model of muco-obstructive lung disease triggered by increased epithelial Na+ absorption, improved MCC, reduced Na+ absorption, and did not change the amount of mucus but did reduce mucus adhesion, neutrophil infiltration, and emphysema. Our data support that KCa3.1 inhibition attenuated muco-obstructive disease in the Scnn1btg/+ mice. K+ channel modulation may be a therapeutic strategy to treat muco-obstructive lung diseases. Silencing the calcium-activated potassium channel KCa.3.1 improves mucociliary clearance in muco-obstructive lung disease by decreasing sodium absorption in the airways.
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Affiliation(s)
| | - Anita Guequén
- Centro de Estudios Científicos, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | - Amber R Philp
- Centro de Estudios Científicos, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | | | - Llilian Arzola
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Manuel Villalón
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Santiago, Chile
| | | | - Luis Jv Galietta
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy.,Department of Translational Medical Sciences, University of Naples Federico II, Naples, Italy
| | - Marcus A Mall
- Department of Pediatric Pulmonology, Immunology and Critical Care Medicine, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Berlin, Germany.,German Center for Lung Research, Berlin, Germany
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15
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Abstract
Ion channels and transporters (ICT) play important roles in almost all basic cellular processes. During last decades, abundant evidences have been provided that ICT (e.g., Ca2+ and K+ channels) are notable for regulating physiological pancreatic duct cellular function and deregulation of ICT is closely associated with the widely accepted hallmarks of pancreatic ductal adenocarcinoma (PDAC) such as proliferation, apoptosis resistance, invasion, and metastasis. Hence this review focuses on the role of ICT malfunctions in context with the hallmarks of PDAC. After briefly introducing epidemiology and history of molecular oncology of PDAC and summarizing the recent studies on molecular classification systems, we focus then on the exocrine pancreas as a very active secretory gland which considerably impacts the changes in the ion transport system (the transportome) upon malignant transformation. We highlight multiplicity of ICT members (H+ transporters, Ca2+, K+, Na+ and Cl- channels) and their functional impact in PDAC. We also present some selective therapeutic options to interfere with transportome functions and thereby with key mechanisms of malignant progression. This will hopefully contribute to a better clinical outcome based on improved therapeutic strategies for this still extremely deadly disease.
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Abstract
Protein Kinase A-Mediated Suppression of the Slow After Hyperpolarizing KCa3.1 Current in Temporal Lobe Epilepsy Tiwari MN, Mohan S, Biala Y, Yaari Y. J Neurosci . 2019;39(50):9914-9926. doi: https://doi.org/10.1523/JNEUROSCI.1603-19 . Brain insults, such as trauma, stroke, anoxia, and status epilepticus (SE), cause multiple changes in synaptic function and intrinsic properties of surviving neurons that may lead to the development of epilepsy. Experimentally, a single SE episode, induced by the convulsant pilocarpine, initiates the development of an epileptic condition resembling human temporal lobe epilepsy (TLE). Principal hippocampal neurons from such epileptic animals display enhanced spike output in response to excitatory stimuli compared with neurons from nonepileptic animals. This enhanced firing is negatively related to the size of the slow afterhyperpolarization (sAHP), which is reduced in the epileptic neurons. The sAHP is an intrinsic neuronal negative feedback mechanism consisting normally of 2 partially overlapping components produced by disparate mechanisms. One component is generated by activation of Ca2+-gated K+ (KCa) channels, likely KCa3.1, consequent to spike Ca2+ influx (the KCa-sAHP component). The second component is generated by enhancement of the electrogenic Na+/K+ ATPase (NKA) by spike Na+ influx (NKA-sAHP component). Here we show that the KCa-sAHP component is markedly reduced in male rat epileptic neurons, whereas the NKA-sAHP component is not altered. The KCa-sAHP reduction is due to the downregulation of KCa3.1 channels, mediated by cAMP-dependent protein kinase A (PKA). This sustained effect can be acutely reversed by applying PKA inhibitors, leading also to normalization of the spike output of epileptic neurons. We propose that the novel “acquired channelopathy” described here, namely, PKA-mediated downregulation of KCa3.1 activity, provides an innovative target for developing new treatments for TLE, hopefully overcoming the pharmacoresistance to traditional drugs. Significance Statement: Epilepsy, a common neurological disorder, often develops following a brain insult. Identifying key molecular and cellular mechanisms underlying acquired epilepsy is critical for developing effective antiepileptic therapies. In an experimental model of acquired epilepsy, we show that principal hippocampal neurons become intrinsically hyperexcitable. This alteration is due predominantly to the downregulation of a ubiquitous class of potassium ion channels, KCa3.1, whose main function is to dampen neuronal excitability. KCa3.1 downregulation is mediated by the cAMP-dependent PKA signaling pathway. Most importantly, it can be acutely reversed by PKA inhibitors, leading to recovery of KCa3.1 function and normalization of neuronal excitability. The discovery of this novel epileptogenic mechanism hopefully will facilitate the development of more efficient pharmacotherapy for acquired epilepsy.
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Amador-Muñoz D, Gutiérrez ÁM, Payán-Gómez C, Matheus LM. In silico and in vitro analysis of cation-activated potassium channels in human corneal endothelial cells. Exp Eye Res 2020; 197:108114. [PMID: 32561484 DOI: 10.1016/j.exer.2020.108114] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 06/02/2020] [Accepted: 06/07/2020] [Indexed: 12/31/2022]
Abstract
The corneal endothelium is the inner cell monolayer involved in the maintenance of corneal transparence by the generation of homeostatic dehydration. The glycosaminoglycans of the corneal stroma develop a continuous swelling pressure that should be counteracted by the corneal endothelial cells through active transport mechanisms to move the water to the anterior chamber. Protein transporters for sodium (Na+), potassium (K+), chloride (Cl-) and bicarbonate (HCO3-) are involved in this endothelial "pump function", however despite its physiological importance, the efflux mechanism is not completely understood. There is experimental evidence describing transendothelial diffusion of water in the absence of osmotic gradients. Therefore, it is important to get a deeper understanding of alternative models that drive the fluid transport across the endothelium such as the electrochemical gradients. Three transcriptomic datasets of the corneal endothelium were used in this study to analyze the expression of genes that encode proteins that participate in the transport and the reestablishment of the membrane potential across the semipermeable endothelium. Subsequently, the expression of the identified channels was validated in vitro both at mRNA and protein levels. The results of this study provide the first evidence of the expression of KCNN2, KCNN3 and KCNT2 genes in the corneal endothelium. Differences among the level of expression of KCNN2, KCNT2 and KCNN4 genes were found in a differentially expressed gene analysis of the dataset. Taken together these results underscore the potential importance of the ionic channels in the pathophysiology of corneal diseases. Moreover, we elucidate novel mechanisms that might be involved in the pivotal dehydrating function of the endothelium and in others physiologic functions of these cells using in silico pathways analysis.
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Affiliation(s)
- Diana Amador-Muñoz
- Neuroscience (NEUROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 No. 63 C 69, P.O 111221, Bogotá, Colombia.
| | - Ángela María Gutiérrez
- Escuela Superior de Oftalmología, Instituto Barraquer de América, Calle 100 No. 18 A 51, Bogotá, Colombia.
| | - César Payán-Gómez
- Department of Biology, Faculty of Natural Sciences, Universidad del Rosario, Carrera 24 No. 63 C 69, Bogotá, P.O 111221, Colombia.
| | - Luisa Marina Matheus
- Neuroscience (NEUROS) Research Group, School of Medicine and Health Sciences, Universidad del Rosario, Carrera 24 No. 63 C 69, P.O 111221, Bogotá, Colombia.
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Therapeutic Effects of Apamin as a Bee Venom Component for Non-Neoplastic Disease. Toxins (Basel) 2020; 12:toxins12030195. [PMID: 32204567 PMCID: PMC7150898 DOI: 10.3390/toxins12030195] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 03/15/2020] [Accepted: 03/17/2020] [Indexed: 02/06/2023] Open
Abstract
Bee venom is a natural toxin produced by honeybees and plays an important role in defending bee colonies. Bee venom has several kinds of peptides, including melittin, apamin, adolapamine, and mast cell degranulation peptides. Apamin accounts for about 2%-3% dry weight of bee venom and is a peptide neurotoxin that contains 18 amino acid residues that are tightly crosslinked by two disulfide bonds. It is well known for its pharmacological functions, which irreversibly block Ca2+-activated K+ (SK) channels. Apamin regulates gene expression in various signal transduction pathways involved in cell development. The aim of this study was to review the current understanding of apamin in the treatment of apoptosis, fibrosis, and central nervous system diseases, which are the pathological processes of various diseases. Apamin's potential therapeutic and pharmacological applications are also discussed.
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19
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Andolfo I, Rosato BE, Manna F, De Rosa G, Marra R, Gambale A, Girelli D, Russo R, Iolascon A. Gain-of-function mutations in PIEZO1 directly impair hepatic iron metabolism via the inhibition of the BMP/SMADs pathway. Am J Hematol 2020; 95:188-197. [PMID: 31737919 DOI: 10.1002/ajh.25683] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 02/06/2023]
Abstract
Dehydrated hereditary stomatocytosis (DHS), or xerocytosis, is an autosomal dominant hemolytic anemia. Most patients with DHS carry mutations in the PIEZO1 gene encoding a mechanosensitive cation channel. We here demonstrate that patients with DHS have low levels of hepcidin and only a slight increase of ERFE, the erythroid negative regulator of hepcidin. We demonstrated that at the physiological level, PIEZO1 activation induced Ca2+ influx and suppression of HAMP expression in primary hepatocytes. In two hepatic cellular models expressing PIEZO1 WT and two PIEZO1 gain-of-function mutants (R2456H and R2488Q), we highlight altered expression of a few genes/proteins involved in iron metabolism. Mutant cells showed increased intracellular Ca2+ compared to WT, which was correlated to increased phosphorylation of ERK1/2, inhibition of the BMP-SMADs pathway, and suppression of HAMP transcription. Moreover, the HuH7 cells, treated with PD0325901, a potent inhibitor of ERK1/2 phosphorylation, reduced the phosphorylation of ERK1/2 with the consequent increased phosphorylation of SMAD1/5/8, confirming the link between the two pathways. Another "proof of concept" for the mechanism that links PIEZO1 to HAMP regulation was obtained by mimicking PIEZO1 activation by cell Ca2+ overload, by the Ca2+ ionophore A23187. There was strong down-regulation of HAMP gene expression after this Ca2+ overload. Finally, the inhibition of PIEZO1 by GsMTx4 leads to phenotype rescue. This is the first demonstration of a direct link between PIEZO1 and iron metabolism, which defines the channel as a new hepatic iron metabolism regulator and as a possible therapeutic target of iron overload in DHS and other iron-loading anemias.
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Affiliation(s)
- Immacolata Andolfo
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
| | - Barbara Eleni Rosato
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
| | - Francesco Manna
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
| | - Gianluca De Rosa
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
| | - Roberta Marra
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
| | - Antonella Gambale
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
| | - Domenico Girelli
- Section of Internal Medicine, Department of MedicineUniversity of Verona Verona Italy
| | - Roberta Russo
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
| | - Achille Iolascon
- Dipartimento di Medicina Molecolare e Biotecnologie MedicheUniversità degli Studi di Napoli ‘Federico II’ Naples Italy
- CEINGE, Biotecnologie Avanzate Naples Italy
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20
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Sikimic J, Hoffmeister T, Gresch A, Kaiser J, Barthlen W, Wolke C, Wieland I, Lendeckel U, Krippeit-Drews P, Düfer M, Drews G. Possible New Strategies for the Treatment of Congenital Hyperinsulinism. Front Endocrinol (Lausanne) 2020; 11:545638. [PMID: 33193079 PMCID: PMC7653201 DOI: 10.3389/fendo.2020.545638] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Accepted: 10/02/2020] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVE Congenital hyperinsulinism (CHI) is a rare disease characterized by persistent hypoglycemia as a result of inappropriate insulin secretion, which can lead to irreversible neurological defects in infants. Poor efficacy and strong adverse effects of the current medications impede successful treatment. The aim of the study was to investigate new approaches to silence β-cells and thus attenuate insulin secretion. RESEARCH DESIGN AND METHODS In the scope of our research, we tested substances more selective and more potent than the gold standard diazoxide that also interact with neuroendocrine ATP-sensitive K+ (KATP) channels. Additionally, KATP channel-independent targets as Ca2+-activated K+ channels of intermediate conductance (KCa3.1) and L-type Ca2+ channels were investigated. Experiments were performed using human islet cell clusters isolated from tissue of CHI patients (histologically classified as pathological) and islet cell clusters obtained from C57BL/6N (WT) or SUR1 knockout (SUR1-/-) mice. The cytosolic Ca2+ concentration ([Ca2+]c) was used as a parameter for the pathway regulated by electrical activity and was determined by fura-2 fluorescence. The mitochondrial membrane potential (ΔΨ) was determined by rhodamine 123 fluorescence and single channel currents were measured by the patch-clamp technique. RESULTS The selective KATP channel opener NN414 (5 µM) diminished [Ca2+]c in isolated human CHI islet cell clusters and WT mouse islet cell clusters stimulated with 10 mM glucose. In islet cell clusters lacking functional KATP channels (SUR1-/-) the drug was without effect. VU0071063 (30 µM), another KATP channel opener considered to be selective, lowered [Ca2+]c in human CHI islet cell clusters. The compound was also effective in islet cell clusters from SUR1-/- mice, showing that [Ca2+]c is influenced by additional effects besides KATP channels. Contrasting to NN414, the drug depolarized ΔΨ in murine islet cell clusters pointing to severe interference with mitochondrial metabolism. An opener of KCa3.1 channels, DCEBIO (100 µM), significantly decreased [Ca2+]c in SUR1-/- and human CHI islet cell clusters. To target L-type Ca2+ channels we tested two already approved drugs, dextromethorphan (DXM) and simvastatin. DXM (100 µM) efficiently diminished [Ca2+]c in stimulated human CHI islet cell clusters as well as in stimulated SUR1-/- islet cell clusters. Similar effects on [Ca2+]c were observed in experiments with simvastatin (7.2 µM). CONCLUSIONS NN414 seems to provide a good alternative to the currently used KATP channel opener diazoxide. Targeting KCa3.1 channels by channel openers or L-type Ca2+ channels by DXM or simvastatin might be valuable approaches for treatment of CHI caused by mutations of KATP channels not sensitive to KATP channel openers.
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Affiliation(s)
- Jelena Sikimic
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Theresa Hoffmeister
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Anne Gresch
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Julia Kaiser
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
| | - Winfried Barthlen
- Department of Pediatric Surgery, University Medicine Greifswald, Greifswald, Germany
| | - Carmen Wolke
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Ilse Wieland
- Institute of Human Genetics, University Hospital Magdeburg, Magdeburg, Germany
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, Greifswald, Germany
| | - Peter Krippeit-Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
- *Correspondence: Peter Krippeit-Drews,
| | - Martina Düfer
- Department of Pharmacology, Institute of Pharmaceutical and Medicinal Chemistry, University of Münster, Münster, Germany
| | - Gisela Drews
- Department of Pharmacology, Institute of Pharmacy, University of Tübingen, Tübingen, Germany
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21
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Derseh HB, Dewage SNV, Perera KUE, Pagel CN, Koumoundouros E, Organ L, Snibson KJ. K Ca3.1 channel blockade attenuates microvascular remodelling in a large animal model of bleomycin-induced pulmonary fibrosis. Sci Rep 2019; 9:19893. [PMID: 31882807 PMCID: PMC6934539 DOI: 10.1038/s41598-019-56412-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Accepted: 12/11/2019] [Indexed: 11/16/2022] Open
Abstract
Idiopathic pulmonary fibrosis (IPF) is a chronic progressive lung disease with limited therapeutic options and poor prognosis. IPF has been associated with aberrant vascular remodelling, however the role of vascular remodelling in pulmonary fibrosis is poorly understood. Here, we used a novel segmental challenge model of bleomycin-induced pulmonary fibrosis in sheep to evaluate the remodelling of the pulmonary vasculature, and to investigate the changes to this remodelling after the administration of the KCa3.1 channel inhibitor, senicapoc, compared to the FDA-approved drug pirfenidone. We demonstrate that in vehicle-treated sheep, bleomycin-infused lung segments had significantly higher blood vessel density when compared to saline-infused control segments in the same sheep. These microvascular density changes were significantly attenuated by senicapoc treatment. The increases in vascular endothelial growth factor (VEGF) expression and endothelial cell proliferation in bleomycin-infused lung segments were significantly reduced in sheep treated with the senicapoc, when compared to vehicle-treated controls. These parameters were not significantly suppressed with pirfenidone treatment. Senicapoc treatment attenuated vascular remodelling through inhibition of capillary endothelial cell proliferation and VEGF expression. These findings suggest a potential new mode of action for the novel drug senicapoc which may contribute to its efficacy in combatting pulmonary fibrosis.
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Affiliation(s)
- Habtamu B Derseh
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia.
| | - Sasika N Vithana Dewage
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Kopiyawaththage U E Perera
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Charles N Pagel
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
| | - Emmanuel Koumoundouros
- Department of Electrical and Electronic Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Louise Organ
- Division of Respiratory Medicine, University of Nottingham, Nottingham, UK
| | - Ken J Snibson
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Parkville, Victoria, Australia
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22
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Hynes D, Harvey BJ. Dexamethasone reduces airway epithelial Cl - secretion by rapid non-genomic inhibition of KCNQ1, KCNN4 and KATP K + channels. Steroids 2019; 151:108459. [PMID: 31330137 DOI: 10.1016/j.steroids.2019.108459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/05/2019] [Accepted: 07/07/2019] [Indexed: 11/26/2022]
Abstract
Basolateral membrane K+ channels play a key role in basal and agonist stimulated Cl- transport across airway epithelial cells by generating a favourable electrical driving force for Cl- efflux. The K+ channel sub-types and molecular mechanisms of regulation by hormones and secretagoues are still poorly understood. Here we have identified the type of K+ channels involved in cAMP and Ca2+ stimulated Cl- secretion and uncovered a novel anti-secretory effect of dexamethasone mediated by inhibition of basolateral membrane K+ channels in a human airway cell model of 16HBE14o- cells commonly used for ion transport studies. Dexamethasone produced a rapid inhibition of transepithelial chloride ion secretion under steady state conditions and after stimulation with cAMP agonist (forskolin) or a Ca2+ mobilizing agonist (ATP). Our results show three different types of K+ channels are targeted by dexamethasone to reduce airway secretion, namely Ca2+-activated secretion via KCNN4 (KCa3.1) channels and cAMP-activated secretion via KCNQ1 (Kv7.1) and KATP (Kir6.1,6.2) channels. The down-regulation of KCNN4 and KCNQ1 channel activities by dexamethasone involves rapid non-genomic activation of PKCα and PKA signalling pathways, respectively. Dexamethasone signal transduction for PKC and PKA activation was demonstrated to occur through a rapid non-genomic pathway that did not implicate the classical nuclear receptors for glucocorticoids or mineralocorticoids but occurred via a novel signalling cascade involving sequentially a Gi-protein coupled receptor, PKC, adenylyl cyclase Type IV, cAMP, PKA and ERK1/2 activation. The rapid, non-genomic, effects of dexamethasone on airway epithelial ion transport and cell signalling introduces a new paradigm for glucocorticoid actions in lung epithelia which may serve to augment the anti-inflammatory activity of the steroid and enhance its therapeutic potential in treating airway hypersecretion in asthma and COPD.
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Affiliation(s)
- Darina Hynes
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland
| | - Brian J Harvey
- Department of Molecular Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin 9, Ireland; Centro di Estudios Cientificos CECs, Valdivia, Chile.
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23
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Shmukler BE, Rivera A, Bhargava P, Nishimura K, Hsu A, Kim EH, Trudel M, Rust MB, Hubner CA, Brugnara C, Alper SL. Combined genetic disruption of K-Cl cotransporters and Gardos channel KCNN4 rescues erythrocyte dehydration in the SAD mouse model of sickle cell disease. Blood Cells Mol Dis 2019; 79:102346. [PMID: 31352162 PMCID: PMC6744291 DOI: 10.1016/j.bcmd.2019.102346] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 07/09/2019] [Accepted: 07/09/2019] [Indexed: 10/26/2022]
Abstract
Excessive red cell dehydration contributes to the pathophysiology of sickle cell disease (SCD). The densest fraction of sickle red cells (with the highest corpuscular hemoglobin concentration) undergoes the most rapid polymerization of deoxy-hemoglobin S, leading to accelerated cell sickling and increased susceptibility to endothelial activation, red cell adhesion, and vaso-occlusion. Increasing red cell volume in order to decrease red cell density can thus serve as an adjunct therapeutic goal in SCD. Regulation of circulating mouse red cell volume and density is mediated largely by the Gardos channel, KCNN4, and the K-Cl cotransporters, KCC3 and KCC1. Whereas inhibition of the Gardos channel in subjects with sickle cell disease increased red cell volume, decreased red cell density, and improved other hematological indices in subjects with SCD, specific KCC inhibitors have not been available for testing. We therefore investigated the effect of genetic inactivation of KCC3 and KCC1 in the SAD mouse model of sickle red cell dehydration, finding decreased red cell density and improved hematological indices. We describe here generation of mice genetically deficient in the three major red cell volume regulatory gene products, KCNN4, KCC3, and KCC1 in C57BL6 non-sickle and SAD sickle backgrounds. We show that combined loss-of-function of all three gene products in SAD mice leads to incrementally increased MCV, decreased CHCM and % hyperchromic cells, decreased red cell density (phthalate method), increased resistance to hypo-osmotic lysis, and increased cell K content. The data show that combined genetic deletion of the Gardos channel and K-Cl cotransporters in a mouse SCD model decreases red cell density and improves several hematological parameters, supporting the strategy of combined pharmacological inhibition of these ion transport pathways in the adjunct treatment of human SCD.
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Affiliation(s)
- Boris E Shmukler
- Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America; Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA 02115, United States of America
| | - Alicia Rivera
- Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America; Department of Medicine, Harvard Medical School, Boston, MA 02115, United States of America; Department of Pathology, Harvard Medical School, Boston, MA 02115, United States of America
| | - Parul Bhargava
- Department of Laboratory Medicine, UCSF, San Francisco, CA, United States of America
| | - Katherine Nishimura
- Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America
| | - Ann Hsu
- Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America
| | - Edward H Kim
- Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America
| | - Marie Trudel
- Institut de Recherches Cliniques de Montreal, Molecular Genetics and Development, Faculte de Medecine, Universite of Montreal, Montreal, Quebec, Canada
| | - Marco B Rust
- Institute of Physiological Chemistry, Philipps-Universität Marburg, Marburg, Germany
| | | | - Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Boston, MA 02115, United States of America; Department of Pathology, Harvard Medical School, Boston, MA 02115, United States of America
| | - Seth L Alper
- Renal Division and Vascular Biology Research Center, Beth Israel Deaconess Medical Center, Boston, MA, United States of America; Department of Medicine, Harvard Medical School, Boston, MA 02115, United States of America.
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24
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Iolascon A, Andolfo I, Russo R. Advances in understanding the pathogenesis of red cell membrane disorders. Br J Haematol 2019; 187:13-24. [PMID: 31364155 DOI: 10.1111/bjh.16126] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hereditary erythrocyte membrane disorders are caused by mutations in genes encoding various transmembrane or cytoskeletal proteins of red blood cells. The main consequences of these genetic alterations are decreased cell deformability and shortened erythrocyte survival. Red blood cell membrane defects encompass a heterogeneous group of haemolytic anaemias caused by either (i) altered membrane structural organisation (hereditary spherocytosis, hereditary elliptocytosis, hereditary pyropoikilocytosis and Southeast Asian ovalocytosis) or (ii) altered membrane transport function (overhydrated hereditary stomatocytosis, dehydrated hereditary stomatocytosis or xerocytosis, familial pseudohyperkalaemia and cryohydrocytosis). Herein we provide a comprehensive review of the recent literature on the molecular genetics of erythrocyte membrane defects and their reported clinical consequences. We also describe the effect of low-expression genetic variants on the high inter- and intra-familial phenotype variability of erythrocyte structural defects.
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Affiliation(s)
- Achille Iolascon
- Department of Molecular Medicine and Medical Biotechnologies, Federico II" University of Naples, Naples, Italy.,CEINGE - Biotecnologie Avanzate, Naples, Italy
| | - Immacolata Andolfo
- Department of Molecular Medicine and Medical Biotechnologies, Federico II" University of Naples, Naples, Italy.,CEINGE - Biotecnologie Avanzate, Naples, Italy
| | - Roberta Russo
- Department of Molecular Medicine and Medical Biotechnologies, Federico II" University of Naples, Naples, Italy.,CEINGE - Biotecnologie Avanzate, Naples, Italy
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25
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Evidence against a Role of Elevated Intracellular Ca 2+ during Plasmodium falciparum Preinvasion. Biophys J 2019; 114:1695-1706. [PMID: 29642038 DOI: 10.1016/j.bpj.2018.02.023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 01/19/2018] [Accepted: 02/09/2018] [Indexed: 12/11/2022] Open
Abstract
Severe malaria is primarily caused by Plasmodium falciparum parasites during their asexual reproduction cycle within red blood cells. One of the least understood stages in this cycle is the brief preinvasion period during which merozoite-red cell contacts lead to apical alignment of the merozoite in readiness for penetration, a stage of major relevance in the control of invasion efficiency. Red blood cell deformations associated with this process were suggested to be active plasma membrane responses mediated by transients of elevated intracellular calcium. Few studies have addressed this hypothesis because of technical challenges, and the results remained inconclusive. Here, Fluo-4 was used as a fluorescent calcium indicator with optimized protocols to investigate the distribution of the dye in red blood cell populations used as P. falciparum invasion targets in egress-invasion assays. Preinvasion dynamics was observed simultaneously under bright-field and fluorescence microscopy by recording egress-invasion events. All the egress-invasion sequences showed red blood cell deformations of varied intensities during the preinvasion period and the echinocytic changes that follow during invasion. Intraerythrocytic calcium signals were absent throughout this interval in over half the records and totally absent during the preinvasion period, regardless of deformation strength. When present, calcium signals were of a punctate modality, initiated within merozoites already poised for invasion. These results argue against a role of elevated intracellular calcium during the preinvasion stage. We suggest an alternative mechanism of merozoite-induced preinvasion deformations based on passive red cell responses to transient agonist-receptor interactions associated with the formation of adhesive coat filaments.
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Kondo Y, Melvin JE, Catalan MA. Physiological cAMP-elevating secretagogues differentially regulate fluid and protein secretions in mouse submandibular and sublingual glands. Am J Physiol Cell Physiol 2019; 316:C690-C697. [PMID: 30840492 DOI: 10.1152/ajpcell.00421.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The mechanisms underlying the functional differences in sympathetic and parasympathetic regulation of the major salivary glands have received little attention. The acute effects of parasympathetic muscarinic (carbachol)-dependent and combined parasympathetic-dependent plus cAMP-dependent pathways on fluid secretion rates, ion composition, and protein content were assessed using a newly developed ex vivo preparation that allows the simultaneous perfusion of the mouse submandibular (SMGs) and sublingual glands (SLGs). Our results confirm that the muscarinic-dependent pathway accounts for the bulk of salivation in SMGs and SLGs, whereas costimulation with a cAMP-increasing agent (forskolin, isoproterenol, or vasoactive intestinal peptide) did not increase the flow rate. Costimulation with carbachol plus the β-adrenergic agonist isoproterenol decreased the concentration of NaCl and produced a substantial increase in the protein and Ca2+ content of SMG but not SLG saliva, consistent with a sparse sympathetic innervation of the SLGs. On the other hand, forskolin, which bypasses receptors to increase intracellular cAMP by directly activating the enzyme adenylate cyclase, enhanced the secretion of protein and Ca2+ by both the SMGs and SLGs. In contrast, isoproterenol and vasoactive intestinal peptide specifically stimulated protein secretion in SMG and SLG salivas, respectively. In summary, cAMP-dependent signaling does not play a major role in the stimulation of fluid secretion in SMGs and SLGs, whereas each cAMP-increasing agonist behaves differently in a gland-specific manner suggesting differential expression of G protein-coupled receptors in the epithelial cells of SMGs and SLGs.
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Affiliation(s)
- Yusuke Kondo
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda, Maryland.,Division of Oral Reconstruction and Rehabilitation, Kyushu Dental University , Fukuoka , Japan
| | - James E Melvin
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda, Maryland
| | - Marcelo A Catalan
- Secretory Mechanisms and Dysfunction Section, Division of Intramural Research, National Institute of Dental and Craniofacial Research, National Institutes of Health , Bethesda, Maryland.,Facultad de Ciencias de la Salud, Universidad Arturo Prat , Iquique , Chile
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27
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Identification of Clotrimazole Derivatives as Specific Inhibitors of Arenavirus Fusion. J Virol 2019; 93:JVI.01744-18. [PMID: 30626681 DOI: 10.1128/jvi.01744-18] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Accepted: 12/21/2018] [Indexed: 02/06/2023] Open
Abstract
Arenaviruses are a large family of emerging enveloped negative-strand RNA viruses that include several causative agents of viral hemorrhagic fevers. For cell entry, human-pathogenic arenaviruses use different cellular receptors and endocytic pathways that converge at the level of acidified late endosomes, where the viral envelope glycoprotein mediates membrane fusion. Inhibitors of arenavirus entry hold promise for therapeutic antiviral intervention and the identification of "druggable" targets is of high priority. Using a recombinant vesicular stomatitis virus pseudotype platform, we identified the clotrimazole-derivative TRAM-34, a highly selective antagonist of the calcium-activated potassium channel KCa3.1, as a specific entry inhibitor for arenaviruses. TRAM-34 specifically blocked entry of most arenaviruses, including hemorrhagic fever viruses, but not Lassa virus and other enveloped viruses. Anti-arenaviral activity was likewise observed with the parental compound clotrimazole and the derivative senicapoc, whereas structurally unrelated KCa3.1 inhibitors showed no antiviral effect. Deletion of KCa3.1 by CRISPR/Cas9 technology did not affect the antiarenaviral effect of TRAM-34, indicating that the observed antiviral effect of clotrimazoles was independent of the known pharmacological target. The drug affected neither virus-cell attachment, nor endocytosis, suggesting an effect on later entry steps. Employing a quantitative cell-cell fusion assay that bypasses endocytosis, we demonstrate that TRAM-34 specifically inhibits arenavirus-mediated membrane fusion. In sum, we uncover a novel antiarenaviral action of clotrimazoles that currently undergo in vivo evaluation in the context of other human diseases. Their favorable in vivo toxicity profiles and stability opens the possibility to repurpose clotrimazole derivatives for therapeutic intervention against human-pathogenic arenaviruses.IMPORTANCE Emerging human-pathogenic arenaviruses are causative agents of severe hemorrhagic fevers with high mortality and represent serious public health problems. The current lack of a licensed vaccine and the limited treatment options makes the development of novel antiarenaviral therapeutics an urgent need. Using a recombinant pseudotype platform, we uncovered that clotrimazole drugs, in particular TRAM-34, specifically inhibit cell entry of a range of arenaviruses, including important emerging human pathogens, with the exception of Lassa virus. The antiviral effect was independent of the known pharmacological drug target and involved inhibition of the unusual membrane fusion mechanism of arenaviruses. TRAM-34 and its derivatives currently undergo evaluation against a number of human diseases and show favorable toxicity profiles and high stability in vivo Our study provides the basis for further evaluation of clotrimazole derivatives as antiviral drug candidates. Their advanced stage of drug development will facilitate repurposing for therapeutic intervention against human-pathogenic arenaviruses.
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Brown BM, Pressley B, Wulff H. KCa3.1 Channel Modulators as Potential Therapeutic Compounds for Glioblastoma. Curr Neuropharmacol 2018; 16:618-626. [PMID: 28676010 PMCID: PMC5997873 DOI: 10.2174/1570159x15666170630164226] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2017] [Revised: 06/01/2017] [Accepted: 06/22/2017] [Indexed: 12/31/2022] Open
Abstract
Background The intermediate-conductance Ca2+-activated K+ channel KCa3.1 is widely expressed in cells of the immune system such as T- and B-lymphocytes, mast cells, macrophages and microglia, but also found in dedifferentiated vascular smooth muscle cells, fibroblasts and many cancer cells including pancreatic, prostate, leukemia and glioblastoma. In all these cell types KCa3.1 plays an important role in cellular activation, migration and proliferation by regulating membrane potential and Ca2+ signaling. Methods and Results KCa3.1 therefore constitutes an attractive therapeutic target for diseases involving excessive proliferation or activation of one more of these cell types and researchers both in academia and in the pharmaceutical industry have developed several potent and selective small molecule inhibitors of KCa3.1. This article will briefly review the available compounds (TRAM-34, senicapoc, NS6180), their binding sites and mechanisms of action, and then discuss the potential usefulness of these compounds for the treatment of brain tumors based on their brain penetration and their efficacy in reducing microglia activation in animal models of ischemic stroke and Alzheimer’s disease. Conclusion Senicapoc, which has previously been in Phase III clinical trials, would be available for repurposing, and could be used to quickly translate findings made with other KCa3.1 blocking tool compounds into clinical trials.
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Affiliation(s)
- Brandon M Brown
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Brandon Pressley
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
| | - Heike Wulff
- Department of Pharmacology, School of Medicine, University of California, Davis, CA 95616, United States
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D'Alessandro G, Limatola C, Catalano M. Functional Roles of the Ca2+-activated K+ Channel, KCa3.1, in Brain Tumors. Curr Neuropharmacol 2018; 16:636-643. [PMID: 28707595 PMCID: PMC5997864 DOI: 10.2174/0929867324666170713103621] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Revised: 06/22/2017] [Accepted: 07/12/2017] [Indexed: 12/23/2022] Open
Abstract
BACKGROUND Glioblastoma is the most aggressive and deadly brain tumor, with low disease-free period even after surgery and combined radio and chemotherapies. Among the factors contributing to the devastating effect of this tumor in the brain are the elevated proliferation and invasion rate, and the ability to induce a local immunosuppressive environment. The intermediateconductance Ca2+-activated K+ channel KCa3.1 is expressed in glioblastoma cells and in tumorinfiltrating cells. METHODS We first describe the researches related to the role of KCa3.1 channels in the invasion of brain tumor cells and the regulation of cell cycle. In the second part we review the involvement of KCa3.1 channel in tumor-associated microglia cell behaviour. RESULTS In tumor cells, the functional expression of KCa3.1 channels is important to substain cell invasion and proliferation. In tumor infiltrating cells, KCa3.1 channel activity is required to regulate their activation state. Interfering with KCa3.1 activity can be an adjuvant therapeutic approach in addition to classic chemotherapy and radiotherapy, to counteract tumor growth and prolong patient's survival. CONCLUSION In this mini-review we discuss the evidence of the functional roles of KCa3.1 channels in glioblastoma biology.
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Affiliation(s)
- Giuseppina D'Alessandro
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,IRCCS Neuromed, Pozzilli, Italy
| | - Cristina Limatola
- IRCCS Neuromed, Pozzilli, Italy.,Department of Physiology and Pharmacology, Laboratory affiliated to Istituto Pasteur Italia-Fondazione Cenci Bolognetti, Sapienza University of Rome, Rome, Italy
| | - Myriam Catalano
- Department of Physiology and Pharmacology, Sapienza University of Rome, Rome, Italy.,IRCCS Neuromed, Pozzilli, Italy
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Xie H, Lu J, Zhu Y, Meng X, Wang R. The KCa3.1 blocker TRAM-34 inhibits proliferation of fibroblasts in paraquat-induced pulmonary fibrosis. Toxicol Lett 2018; 295:408-415. [PMID: 30036685 DOI: 10.1016/j.toxlet.2018.07.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 07/15/2018] [Accepted: 07/19/2018] [Indexed: 01/30/2023]
Abstract
KCa3.1, a Ca2+-activated K+ channel, plays an important role in modulating calcium signaling and maintaining membrane potential during cell activation. It has been reported to promote fibroblast function in many fibrotic diseases. However, the role of KCa3.1 in the pathophysiology of pulmonary fibrosis after paraquat (PQ) poisoning has not been studied. A rat model of PQ poisoning was used. After treatment with TRAM-34, which is a highly selective KCa3.1 blocker, the expression of KCa3.1, TGF-β1 and α-SMA were evaluated via Western blot, histology and other assays. Bromodeoxyuridine (BrdU) marking and MTT assay were used to measure primary rat pulmonary fibroblast proliferation. The results showed that KCa3.1 expression was elevated after PQ poisoning. Blockade of KCa3.1 alleviated PQ-induced pulmonary inflammation and fibrosis. Blockade of KCa3.1 also attenuated the level of collagen I and α-SMA and the proliferation of fibroblasts. However, TGF-β1 expression remained unaffected by blockade of KCa3.1 in rat lung tissues after PQ poisoning. The present study suggests that KCa3.1 expression increased and might promote pulmonary fibroblast proliferation in PQ-induced pulmonary fibrosis. In addition, we confirmed that TRAM-34 attenuates proliferation and collagen secretion of fibroblasts. Our findings indicated that TRAM-34 might inhibit PQ-induced proliferation of pulmonary fibroblasts and prevent progression of lung fibrosis.
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Affiliation(s)
- Hui Xie
- Department of Critical Care Medicine, Shanghai General Hospital of Nanjing Medical University, Shanghai 201620, China
| | - Jian Lu
- Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 201620, China
| | - Yong Zhu
- Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 201620, China
| | - Xiaoxiao Meng
- Department of Critical Care Medicine, Shanghai General Hospital, Shanghai Jiaotong University, School of Medicine, Shanghai 201620, China
| | - Ruilan Wang
- Department of Critical Care Medicine, Shanghai General Hospital of Nanjing Medical University, Shanghai 201620, China.
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Rauner G, Kudinov T, Gilad S, Hornung G, Barash I. High Expression of CD200 and CD200R1 Distinguishes Stem and Progenitor Cell Populations within Mammary Repopulating Units. Stem Cell Reports 2018; 11:288-302. [PMID: 29937142 PMCID: PMC6067058 DOI: 10.1016/j.stemcr.2018.05.013] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Revised: 05/23/2018] [Accepted: 05/23/2018] [Indexed: 01/13/2023] Open
Abstract
Aiming to unravel the top of the mammary epithelial cell hierarchy, a subset of the CD49fhighCD24med mammary repopulating units (MRUs) was identified by flow cytometry, expressing high levels of CD200 and its receptor CD200R1. These MRUCD200/CD200R1 repopulated a larger area of de-epithelized mammary fat pads than the rest of the MRUs, termed MRUnot CD200/CD200R1. MRUCD200/CD200R1 maintained a much lower number of divergently defined, highly expressed genes and pathways that support better cell growth, development, differentiation, and progenitor activity than their MRUnot CD200/CD200R1 counterparts. A defined profile of hierarchically associated genes supporting a single-lineage hypothesis was confirmed by in vitro mammosphere analysis that assembled 114 genes with decreased expression from MRUCD200/CD200R1 via MRUnot CD200/CD200R1 toward CD200+CD200R1- and CD200R1+CD200- cells. About 40% of these genes were shared by a previously published database of upregulated genes in mammary/breast stem cells and may represent the core genes involved in mammary stemness.
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Affiliation(s)
- Gat Rauner
- Institute of Animal Science, ARO, The Volcani Center, Bet-Dagan 50250, Israel; The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Jerusalem 7610001, Israel
| | - Tania Kudinov
- Institute of Animal Science, ARO, The Volcani Center, Bet-Dagan 50250, Israel; The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Jerusalem 7610001, Israel
| | - Shlomit Gilad
- The Nancy & Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Gil Hornung
- The Nancy & Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Itamar Barash
- Institute of Animal Science, ARO, The Volcani Center, Bet-Dagan 50250, Israel.
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32
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Philp AR, Riquelme TT, Millar-Büchner P, González R, Sepúlveda FV, Cid LP, Flores CA. Kcnn4 is a modifier gene of intestinal cystic fibrosis preventing lethality in the Cftr-F508del mouse. Sci Rep 2018; 8:9320. [PMID: 29915289 PMCID: PMC6006244 DOI: 10.1038/s41598-018-27465-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 06/04/2018] [Indexed: 02/07/2023] Open
Abstract
Nearly 70% of cystic fibrosis (CF) patients bear the phenylalanine-508 deletion but disease severity differs greatly, and is not explained by the existence of different mutations in compound heterozygous. Studies demonstrated that genes other than CFTR relate to intestinal disease in humans and CF-mouse. Kcnn4, the gene encoding the calcium-activated potassium channel KCa3.1, important for intestinal secretion, is present in a locus linked with occurrence of intestinal CF-disease in mice and humans. We reasoned that it might be a CF-modifier gene and bred a CF-mouse with Kcnn4 silencing, finding that lethality was almost abolished. Silencing of Kcnn4 did not improve intestinal secretory functions, but rather corrected increased circulating TNF-α level and reduced intestinal mast cell increase. Given the importance of mast cells in intestinal disease additional double mutant CF-animals were tested, one lacking mast cells (C-kitW-sh/W-sh) and Stat6-/- to block IgE production. While mast cell depletion had no effect, silencing Stat6 significantly reduced lethality. Our results show that Kcnn4 is an intestinal CF modifier gene partially acting through a STAT6-dependent mechanism.
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Affiliation(s)
- Amber R Philp
- Centro de Estudios Científicos (CECs), Arturo Prat 514, Valdivia, Chile
- Universidad Austral de Chile, Valdivia, Chile
| | - Texia T Riquelme
- Centro de Estudios Científicos (CECs), Arturo Prat 514, Valdivia, Chile
| | - Pamela Millar-Büchner
- Centro de Estudios Científicos (CECs), Arturo Prat 514, Valdivia, Chile
- Department of Translational Pulmonology, Translational Lung Research Center Heidelberg (TLRC), Member of the German Center for Lung Research (DZL), University of Heidelberg, Heidelberg, Germany
| | - Rodrigo González
- Centro de Estudios Científicos (CECs), Arturo Prat 514, Valdivia, Chile
| | | | - L Pablo Cid
- Centro de Estudios Científicos (CECs), Arturo Prat 514, Valdivia, Chile
| | - Carlos A Flores
- Centro de Estudios Científicos (CECs), Arturo Prat 514, Valdivia, Chile.
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Regulatory Effect of General Anesthetics on Activity of Potassium Channels. Neurosci Bull 2018; 34:887-900. [PMID: 29948841 PMCID: PMC6129254 DOI: 10.1007/s12264-018-0239-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2017] [Accepted: 04/12/2018] [Indexed: 12/19/2022] Open
Abstract
General anesthesia is an unconscious state induced by anesthetics for surgery. The molecular targets and cellular mechanisms of general anesthetics in the mammalian nervous system have been investigated during past decades. In recent years, K+ channels have been identified as important targets of both volatile and intravenous anesthetics. This review covers achievements that have been made both on the regulatory effect of general anesthetics on the activity of K+ channels and their underlying mechanisms. Advances in research on the modulation of K+ channels by general anesthetics are summarized and categorized according to four large K+ channel families based on their amino-acid sequence homology. In addition, research achievements on the roles of K+ channels in general anesthesia in vivo, especially with regard to studies using mice with K+ channel knockout, are particularly emphasized.
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34
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Kaestner L, Wang X, Hertz L, Bernhardt I. Voltage-Activated Ion Channels in Non-excitable Cells-A Viewpoint Regarding Their Physiological Justification. Front Physiol 2018; 9:450. [PMID: 29755371 PMCID: PMC5934782 DOI: 10.3389/fphys.2018.00450] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Accepted: 04/10/2018] [Indexed: 01/27/2023] Open
Affiliation(s)
- Lars Kaestner
- Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany.,Experimental Physics, Saarland University, Saarbrücken, Germany
| | - Xijia Wang
- Laboratory of Biophysics, Saarland University, Saarbrücken, Germany
| | - Laura Hertz
- Medical Faculty, Institute for Molecular Cell Biology, Saarland University, Homburg, Germany
| | - Ingolf Bernhardt
- Laboratory of Biophysics, Saarland University, Saarbrücken, Germany
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35
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Anumanthan G, Gupta S, Fink MK, Hesemann NP, Bowles DK, McDaniel LM, Muhammad M, Mohan RR. KCa3.1 ion channel: A novel therapeutic target for corneal fibrosis. PLoS One 2018; 13:e0192145. [PMID: 29554088 PMCID: PMC5858751 DOI: 10.1371/journal.pone.0192145] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2017] [Accepted: 01/17/2018] [Indexed: 12/16/2022] Open
Abstract
Vision impairment from corneal fibrosis is a common consequence of irregular corneal wound healing after injury. Intermediate-conductance calmodulin/calcium-activated K+ channels 3.1 (KCa3.1) play an important role in cell cycle progression and cellular proliferation. Proliferation and differentiation of corneal fibroblasts to myofibroblasts can lead to corneal fibrosis after injury. KCa3.1 has been shown in many non-ocular tissues to promote fibrosis, but its role in corneal fibrosis is still unknown. In this study, we characterized the expression KCa3.1 in the human cornea and its role in corneal wound healing in vivo using a KCa3.1 knockout (KCa3.1-/-) mouse model. Additionally, we tested the hypothesis that blockade of KCa3.1 by a selective KCa3.1 inhibitor, TRAM-34, could augment a novel interventional approach for controlling corneal fibrosis in our established in vitro model of corneal fibrosis. The expression of KCa3.1 gene and protein was analyzed in human and murine corneas. Primary human corneal fibroblast (HCF) cultures were used to examine the potential of TRAM-34 in treating corneal fibrosis by measuring levels of pro-fibrotic genes, proteins, and cellular migration using real-time quantitative qPCR, Western blotting, and scratch assay, respectively. Cytotoxicity of TRAM-34 was tested with trypan blue assay, and pro-fibrotic marker expression was tested in KCa3.1-/-. Expression of KCa3.1 mRNA and protein was detected in all three layers of the human cornea. The KCa3.1-/- mice demonstrated significantly reduced corneal fibrosis and expression of pro-fibrotic marker genes such as collagen I and α-smooth muscle actin (α-SMA), suggesting that KCa3.1 plays an important role corneal wound healing in vivo. Pharmacological treatment with TRAM-34 significantly attenuated corneal fibrosis in vitro, as demonstrated in HCFs by the inhibition TGFβ-mediated transcription of pro-fibrotic collagen I mRNA and α-SMA mRNA and protein expression (p<0.001). No evidence of cytotoxicity was observed. Our study suggests that KCa3.1 regulates corneal wound healing and that blockade of KCa3.1 by TRAM-34 offers a potential therapeutic strategy for developing therapies to cure corneal fibrosis in vivo.
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Affiliation(s)
- Govindaraj Anumanthan
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Suneel Gupta
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Michael K. Fink
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Nathan P. Hesemann
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Mason Eye Institute, University of Missouri School of Medicine, Columbia, Missouri, United States of America
| | - Douglas K. Bowles
- Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
| | - Lindsey M. McDaniel
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Mason Eye Institute, University of Missouri School of Medicine, Columbia, Missouri, United States of America
| | - Maaz Muhammad
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
| | - Rajiv R. Mohan
- Harry S. Truman Memorial Veteran Hospital, Columbia, Missouri, United States of America
- Veterinary Medicine and Surgery, University of Missouri, Columbia, Missouri, United States of America
- Mason Eye Institute, University of Missouri School of Medicine, Columbia, Missouri, United States of America
- Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
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36
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Abstract
Cell dehydration is a distinguishing characteristic of sickle cell disease and an important contributor to disease pathophysiology. Due to the unique dependence of Hb S polymerization on cellular Hb S concentration, cell dehydration promotes polymerization and sickling. In double heterozygosis for Hb S and C (SC disease) dehydration is the determining factor in disease pathophysiology. Three major ion transport pathways are involved in sickle cell dehydration: the K-Cl cotransport (KCC), the Gardos channel (KCNN4) and Psickle, the polymerization induced membrane permeability, most likely mediated by the mechano-sensitive ion channel PIEZO1. Each of these pathways exhibit unique characteristics in regulation by oxygen tension, intracellular and extracellular environment, and functional expression in reticulocytes and mature red cells. The unique dependence of K-Cl cotransport on intracellular Mg and the abnormal reduction of erythrocyte Mg content in SS and SC cells had led to clinical studies assessing the effect of oral Mg supplementation. Inhibition of Gardos channel by clotrimazole and senicapoc has led to Phase 1,2,3 trials in patients with sickle cell disease. While none of these studies has resulted in the approval of a novel therapy for SS disease, they have highlighted the key role played by these pathways in disease pathophysiology.
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Affiliation(s)
- Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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Sforna L, Megaro A, Pessia M, Franciolini F, Catacuzzeno L. Structure, Gating and Basic Functions of the Ca2+-activated K Channel of Intermediate Conductance. Curr Neuropharmacol 2018; 16:608-617. [PMID: 28875832 PMCID: PMC5997868 DOI: 10.2174/1570159x15666170830122402] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2017] [Revised: 07/21/2017] [Accepted: 07/22/2017] [Indexed: 01/04/2023] Open
Abstract
BACKGROUND The KCa3.1 channel is the intermediate-conductance member of the Ca2+- activated K channel superfamily. It is widely expressed in excitable and non-excitable cells, where it plays a major role in a number of cell functions. This paper aims at illustrating the main structural, biophysical and modulatory properties of the KCa3.1 channel, and providing an account of experimental data on its role in volume regulation and Ca2+ signals. METHODS Research and online content related to the structure, structure/function relationship, and physiological role of the KCa3.1 channel are reviewed. RESULTS Expressed in excitable and non-excitable cells, the KCa3.1 channel is voltage independent, its opening being exclusively gated by the binding of intracellular Ca2+ to calmodulin, a Ca2+- binding protein constitutively associated with the C-terminus of each KCa3.1 channel α subunit. The KCa3.1 channel activates upon high affinity Ca2+ binding, and in highly coordinated fashion giving steep Hill functions and relatively low EC50 values (100-350 nM). This high Ca2+ sensitivity is physiologically modulated by closely associated kinases and phosphatases. The KCa3.1 channel is normally activated by global Ca2+ signals as resulting from Ca2+ released from intracellular stores, or by the refilling influx through store operated Ca2+ channels, but cases of strict functional coupling with Ca2+-selective channels are also found. KCa3.1 channels are highly expressed in many types of cells, where they play major roles in cell migration and death. The control of these complex cellular processes is achieved by KCa3.1 channel regulation of the driving force for Ca2+ entry from the extracellular medium, and by mediating the K+ efflux required for cell volume control. CONCLUSION Much work remains to be done to fully understand the structure/function relationship of the KCa3.1 channels. Hopefully, this effort will provide the basis for a beneficial modulation of channel activity under pathological conditions.
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Affiliation(s)
| | | | | | - Fabio Franciolini
- Address correspondence to these authors at the Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Pascoli, 8-06123, Perugia; Tel: 39.075.585.5751; E-mails: and
| | - Luigi Catacuzzeno
- Address correspondence to these authors at the Department of Chemistry, Biology and Biotechnology, University of Perugia, Via Pascoli, 8-06123, Perugia; Tel: 39.075.585.5751; E-mails: and
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Andolfo I, Russo R, Gambale A, Iolascon A. Hereditary stomatocytosis: An underdiagnosed condition. Am J Hematol 2018; 93:107-121. [PMID: 28971506 DOI: 10.1002/ajh.24929] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 09/26/2017] [Accepted: 09/27/2017] [Indexed: 12/11/2022]
Abstract
Hereditary stomatocytoses are a wide class of hemolytic anemias characterized by alterations of ionic flux with increased cation permeability that results in inappropriate shrinkage or swelling of the erythrocytes, and water lost or gained osmotically. The last few years have been crucial for new acquisitions in this field in terms of identifying new causative genes and of studying their pathogenetic mechanisms. This review summarizes the main features of erythrocyte membrane transport diseases, dividing them into forms with either isolated erythroid phenotype (nonsyndromic) or extra-hematological manifestations (syndromic), and focusing particularly on the most recent advances regarding dehydrated forms of hereditary stomatocytosis and familial pseudohyperkalemia.
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Affiliation(s)
- Immacolata Andolfo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
| | - Roberta Russo
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
| | - Antonella Gambale
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
| | - Achille Iolascon
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II; Napoli Italy
- CEINGE Biotecnologie Avanzate; Napoli Italy
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Julio-Kalajzić F, Villanueva S, Burgos J, Ojeda M, Cid LP, Jentsch TJ, Sepúlveda FV. K 2P TASK-2 and KCNQ1-KCNE3 K + channels are major players contributing to intestinal anion and fluid secretion. J Physiol 2017; 596:393-407. [PMID: 29143340 DOI: 10.1113/jp275178] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2017] [Accepted: 11/08/2017] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS K+ channels are important in intestinal epithelium as they ensure the ionic homeostasis and electrical potential of epithelial cells during anion and fluid secretion. Intestinal epithelium cAMP-activated anion secretion depends on the activity of the (also cAMP dependent) KCNQ1-KCNE3 K+ channel, but the secretory process survives after genetic inactivation of the K+ channel in the mouse. Here we use double mutant mice to investigate which alternative K+ channels come into action to compensate for the absence of KCNQ1-KCNE3 K+ channels. Our data establish that whilst Ca2+ -activated KCa 3.1 channels are not involved, K2P two-pore domain TASK-2 K+ channels are major players providing an alternative conductance to sustain the intestinal secretory process. Work with double mutant mice lacking both TASK-2 and KCNQ1-KCNE3 channels nevertheless points to yet-unidentified K+ channels that contribute to the robustness of the cAMP-activated anion secretion process. ABSTRACT Anion and fluid secretion across the intestinal epithelium, a process altered in cystic fibrosis and secretory diarrhoea, is mediated by cAMP-activated CFTR Cl- channels and requires the simultaneous activity of basolateral K+ channels to maintain cellular ionic homeostasis and membrane potential. This function is fulfilled by the cAMP-activated K+ channel formed by the association of pore-forming KCNQ1 with its obligatory KCNE3 β-subunit. Studies using mice show sizeable cAMP-activated intestinal anion secretion in the absence of either KCNQ1 or KCNE3 suggesting that an alternative K+ conductance must compensate for the loss of KCNQ1-KCNE3 activity. We used double mutant mouse and pharmacological approaches to identify such a conductance. Ca2+ -dependent anion secretion can also be supported by Ca2+ -dependent KCa 3.1 channels after independent CFTR activation, but cAMP-dependent anion secretion is not further decreased in the combined absence of KCa 3.1 and KCNQ1-KCNE3 K+ channel activity. We show that the K2P K+ channel TASK-2 is expressed in the epithelium of the small and large intestine. Tetrapentylammonium, a TASK-2 inhibitor, abolishes anion secretory current remaining in the absence of KCNQ1-KCNE3 activity. A double mutant mouse lacking both KCNQ1-KCNE3 and TASK-2 showed a much reduced cAMP-mediated anion secretion compared to that observed in the single KCNQ1-KCNE3 deficient mouse. We conclude that KCNQ1-KCNE3 and TASK-2 play major roles in the intestinal anion and fluid secretory phenotype. The persistence of an, admittedly reduced, secretory activity in the absence of these two conductances suggests that further additional K+ channel(s) as yet unidentified contribute to the robustness of the intestinal anion secretory process.
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Affiliation(s)
| | - Sandra Villanueva
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | - Johanna Burgos
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia, Chile.,Universidad Austral de Chile, Valdivia, Chile
| | - Margarita Ojeda
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia, Chile
| | - L Pablo Cid
- Centro de Estudios Científicos (CECs), Avenida Arturo Prat 514, Valdivia, Chile
| | - Thomas J Jentsch
- Leibniz-Institut für Molekulare Pharmakologie (FMP) and Max-Delbrück-Centrum für Molekulare Medizin (MDC), Berlin, Germany
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Danielczok JG, Terriac E, Hertz L, Petkova-Kirova P, Lautenschläger F, Laschke MW, Kaestner L. Red Blood Cell Passage of Small Capillaries Is Associated with Transient Ca 2+-mediated Adaptations. Front Physiol 2017; 8:979. [PMID: 29259557 PMCID: PMC5723316 DOI: 10.3389/fphys.2017.00979] [Citation(s) in RCA: 70] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2017] [Accepted: 11/16/2017] [Indexed: 12/15/2022] Open
Abstract
When red blood cells (RBCs) pass constrictions or small capillaries they need to pass apertures falling well below their own cross section size. We used different means of mechanical stimulations (hypoosmotic swelling, local mechanical stimulation, passing through microfluidic constrictions) to observe cellular responses of human RBCs in terms of intracellular Ca2+-signaling by confocal microscopy of Fluo-4 loaded RBCs. We were able to confirm our in vitro results in a mouse dorsal skinfold chamber model showing a transiently increased intracellular Ca2+ when RBCs were passing through small capillaries in vivo. Furthermore, we performed the above-mentioned in vitro experiments as well as measurements of RBCs filterability under various pharmacological manipulations (GsMTx-4, TRAM-34) to explore the molecular mechanism of the Ca2+-signaling. Based on these experiments we conclude that mechanical stimulation of RBCs activates mechano-sensitive channels most likely Piezo1. This channel activity allows Ca2+ to enter the cell, leading to a transient activation of the Gardos-channel associated with K+, Cl-, and water loss, i.e., with a transient volume adaptation facilitating the passage of the RBCs through the constriction.
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Affiliation(s)
- Jens G Danielczok
- Institute for Molecular Cell Biology, Saarland University, Homburg, Germany
| | - Emmanuel Terriac
- Experimental Physics, Saarland University, Saarbrücken, Germany.,Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Laura Hertz
- Institute for Molecular Cell Biology, Saarland University, Homburg, Germany
| | | | - Franziska Lautenschläger
- Experimental Physics, Saarland University, Saarbrücken, Germany.,Leibniz Institute for New Materials, Saarbrücken, Germany
| | - Matthias W Laschke
- Institute for Clinical and Experimental Surgery, Saarland University, Homburg, Germany
| | - Lars Kaestner
- Experimental Physics, Saarland University, Saarbrücken, Germany.,Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany
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Yi M, Wei T, Wang Y, Lu Q, Chen G, Gao X, Geller HM, Chen H, Yu Z. The potassium channel KCa3.1 constitutes a pharmacological target for astrogliosis associated with ischemia stroke. J Neuroinflammation 2017; 14:203. [PMID: 29037241 PMCID: PMC5644250 DOI: 10.1186/s12974-017-0973-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 09/27/2017] [Indexed: 12/11/2022] Open
Abstract
Background Reactive astrogliosis is one of the significantly pathological features in ischemic stroke accompanied with changes in gene expression, morphology, and proliferation. KCa3.1 was involved in TGF-β-induced astrogliosis in vitro and also contributed to astrogliosis-mediated neuroinflammation in neurodegeneration disease. Methods Wild type mice and KCa3.1−/− mice were subjected to permanent middle cerebral artery occlusion (pMCAO) to evaluate the infarct areas by 2,3,5-triphenyltetrazolium hydrochloride staining and neurological deficit. KCa3.1 channels expression and cell localization in the brain of pMCAO mice model were measured by immunoblotting and immunostaining. Glia activation and neuron loss was measured by immunostaining. DiBAC4 (3) and Fluo-4AM were used to measure membrane potential and cytosolic Ca2+ level in oxygen-glucose deprivation induced reactive astrocytes in vitro. Results Immunohistochemistry on pMCAO mice infarcts showed strong upregulation of KCa3.1 immunoreactivity in reactive astrogliosis. KCa3.1−/− mice exhibited significantly smaller infarct areas on pMCAO and improved neurological deficit. Both activated gliosis and neuronal loss were attenuated in KCa3.1−/− pMCAO mice. In the primary cultured astrocytes, the expressions of KCa3.1 and TRPV4 were increased associated with upregulation of astrogliosis marker GFAP induced by oxygen-glucose deprivation. The activation of KCa3.1 hyperpolarized membrane potential and, by promoting the driving force for calcium, induced calcium entry through TRPV4, a cation channel of the transient receptor potential family. Double-labeled staining showed that KCa3.1 and TRPV4 channels co-localized in astrocytes. Blockade of KCa3.1 or TRPV4 inhibited the phenotype switch of reactive astrogliosis. Conclusions Our data suggested that KCa3.1 inhibition might represent a promising therapeutic strategy for ischemia stroke. Electronic supplementary material The online version of this article (10.1186/s12974-017-0973-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Mengni Yi
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Tianjiao Wei
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Yanxia Wang
- Experimental Teaching Center of Basic Medicine, School of Medicine, Shanghai Jiao Tong University, Shanghai, 200025, China
| | - Qin Lu
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Gaoxian Chen
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Xiaoling Gao
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China
| | - Herbert M Geller
- Developmental Neurobiology Section, Division of Intramural Research, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Hongzhuan Chen
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
| | - Zhihua Yu
- Department of Pharmacology, Institute of Medical Sciences, Shanghai Jiao Tong University School of Medicine, Shanghai, 200025, China.
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Steudel FA, Mohr CJ, Stegen B, Nguyen HY, Barnert A, Steinle M, Beer‐Hammer S, Koch P, Lo W, Schroth W, Hoppe R, Brauch H, Ruth P, Huber SM, Lukowski R. SK4 channels modulate Ca 2+ signalling and cell cycle progression in murine breast cancer. Mol Oncol 2017; 11:1172-1188. [PMID: 28557306 PMCID: PMC5579333 DOI: 10.1002/1878-0261.12087] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/27/2017] [Accepted: 05/16/2017] [Indexed: 01/08/2023] Open
Abstract
Oncogenic signalling via Ca2+ -activated K+ channels of intermediate conductance (SK4, also known as KCa 3.1 or IK) has been implicated in different cancer entities including breast cancer. Yet, the role of endogenous SK4 channels for tumorigenesis is unclear. Herein, we generated SK4-negative tumours by crossing SK4-deficient (SK4 KO) mice to the polyoma middle T-antigen (PyMT) and epidermal growth factor receptor 2 (cNeu) breast cancer models in which oncogene expression is driven by the retroviral promoter MMTV. Survival parameters and tumour progression were studied in cancer-prone SK4 KO in comparison with wild-type (WT) mice and in a syngeneic orthotopic mouse model following transplantation of SK4-negative or WT tumour cells. SK4 activity was modulated by genetic or pharmacological means using the SK4 inhibitor TRAM-34 in order to establish the role of breast tumour SK4 for cell growth, electrophysiological signalling, and [Ca2+ ]i oscillations. Ablation of SK4 and TRAM-34 treatment reduced the SK4-generated current fraction, growth factor-dependent Ca2+ entry, cell cycle progression and the proliferation rate of MMTV-PyMT tumour cells. In vivo, PyMT oncogene-driven tumorigenesis was only marginally affected by the global lack of SK4, whereas tumour progression was significantly delayed after orthotopic implantation of MMTV-PyMT SK4 KO breast tumour cells. However, overall survival and progression-free survival time in the MMTV-cNeu mouse model were significantly extended in the absence of SK4. Collectively, our data from murine breast cancer models indicate that SK4 activity is crucial for cell cycle control. Thus, the modulation of this channel should be further investigated towards a potential improvement of existing antitumour strategies in human breast cancer.
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Affiliation(s)
- Friederike A. Steudel
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Corinna J. Mohr
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Benjamin Stegen
- Department of Radiation OncologyUniversity of TuebingenGermany
| | - Hoang Y. Nguyen
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Andrea Barnert
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Marc Steinle
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | - Sandra Beer‐Hammer
- Department of Pharmacology and Experimental TherapyInstitute of Experimental and Clinical Pharmacology and ToxicologyUniversity Hospital TuebingenGermany
| | - Pierre Koch
- Pharmaceutical and Medicinal ChemistryInstitute of PharmacyUniversity of TuebingenGermany
| | - Wing‐Yee Lo
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Werner Schroth
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Reiner Hoppe
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
| | - Hiltrud Brauch
- Dr. Margarete Fischer‐Bosch‐Institute of Clinical PharmacologyStuttgart and University of TuebingenGermany
- German Cancer Consortium (DKTK)German Cancer Research Center (DKFZ)HeidelbergGermany
| | - Peter Ruth
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
| | | | - Robert Lukowski
- Department of Pharmacology, Toxicology and Clinical PharmacyInstitute of PharmacyUniversity of TuebingenGermany
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The Slo(w) path to identifying the mitochondrial channels responsible for ischemic protection. Biochem J 2017; 474:2067-2094. [PMID: 28600454 DOI: 10.1042/bcj20160623] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2017] [Revised: 02/10/2017] [Accepted: 02/13/2017] [Indexed: 12/19/2022]
Abstract
Mitochondria play an important role in tissue ischemia and reperfusion (IR) injury, with energetic failure and the opening of the mitochondrial permeability transition pore being the major causes of IR-induced cell death. Thus, mitochondria are an appropriate focus for strategies to protect against IR injury. Two widely studied paradigms of IR protection, particularly in the field of cardiac IR, are ischemic preconditioning (IPC) and volatile anesthetic preconditioning (APC). While the molecular mechanisms recruited by these protective paradigms are not fully elucidated, a commonality is the involvement of mitochondrial K+ channel opening. In the case of IPC, research has focused on a mitochondrial ATP-sensitive K+ channel (mitoKATP), but, despite recent progress, the molecular identity of this channel remains a subject of contention. In the case of APC, early research suggested the existence of a mitochondrial large-conductance K+ (BK, big conductance of potassium) channel encoded by the Kcnma1 gene, although more recent work has shown that the channel that underlies APC is in fact encoded by Kcnt2 In this review, we discuss both the pharmacologic and genetic evidence for the existence and identity of mitochondrial K+ channels, and the role of these channels both in IR protection and in regulating normal mitochondrial function.
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Organ L, Bacci B, Koumoundouros E, Kimpton WG, Samuel CS, Nowell CJ, Bradding P, Roach KM, Westall G, Jaffar J, Snibson KJ. Inhibition of the KCa3.1 Channel Alleviates Established Pulmonary Fibrosis in a Large Animal Model. Am J Respir Cell Mol Biol 2017; 56:539-550. [DOI: 10.1165/rcmb.2016-0092oc] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Affiliation(s)
- Louise Organ
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Barbara Bacci
- School of Veterinary Medicine, University of Surrey, Guildford, United Kingdom
| | - Emmanuel Koumoundouros
- Department of Electrical and Electronic Engineering, The University of Melbourne, Parkville, Victoria, Australia
| | - Wayne G. Kimpton
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Parkville, Victoria, Australia
| | - Chrishan S. Samuel
- Cardiovascular Disease Program, Biomedical Discovery Institute and Department of Pharmacology, Monash University, Clayton, Victoria, Australia
| | - Cameron J. Nowell
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia
| | - Peter Bradding
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom; and
| | - Katy M. Roach
- Department of Infection, Immunity and Inflammation, Institute for Lung Health, University of Leicester, Leicester, United Kingdom; and
| | - Glen Westall
- Department of Allergy, Immunology and Respiratory Medicine, Alfred Hospital Melbourne, Victoria, Australia
| | - Jade Jaffar
- Department of Allergy, Immunology and Respiratory Medicine, Alfred Hospital Melbourne, Victoria, Australia
| | - Ken J. Snibson
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Parkville, Victoria, Australia
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KCa3.1 mediates dysfunction of tubular autophagy in diabetic kidneys via PI3k/Akt/mTOR signaling pathways. Sci Rep 2016; 6:23884. [PMID: 27029904 PMCID: PMC4814925 DOI: 10.1038/srep23884] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 02/16/2016] [Indexed: 02/06/2023] Open
Abstract
Autophagy is emerging as an important pathway in many diseases including diabetic nephropathy. It is acknowledged that oxidative stress plays a critical role in autophagy dysfunction and diabetic nephropathy, and KCa3.1 blockade ameliorates diabetic renal fibrosis through inhibiting TGF-β1 signaling pathway. To identify the role of KCa3.1 in dysfunctional tubular autophagy in diabetic nephropathy, human proximal tubular cells (HK2) transfected with scrambled or KCa3.1 siRNAs were exposed to TGF-β1 for 48 h, then autophagosome formation, the autophagy marker LC3, signaling molecules PI3K, Akt and mTOR, and oxidative stress marker nitrotyrosine were examined respectively. In vivo, LC3, nitrotyrosine and phosphorylated mTOR were examined in kidneys of diabetic KCa3.1+/+ and KCa3.1-/- mice. The results demonstrated that TGF-β1 increased the formation of autophagic vacuoles, LC3 expression, and phosphorylation of PI3K, Akt and mTOR in scrambled siRNA transfected HK2 cells compared to control cells, which was reversed in KCa3.1 siRNA transfected HK2 cells. In vivo, expression of LC3 and nitrotyrosine, and phosphorylation of mTOR were significantly increased in kidneys of diabetic KCa3.1+/+ mice compared to non-diabetic mice, which were attenuated in kidneys of diabetic KCa3.1-/- mice. These results suggest that KCa3.1 activation contributes to dysfunctional tubular autophagy in diabetic nephropathy through PI3K/Akt/mTOR signaling pathways.
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Petho Z, Balajthy A, Bartok A, Bene K, Somodi S, Szilagyi O, Rajnavolgyi E, Panyi G, Varga Z. The anti-proliferative effect of cation channel blockers in T lymphocytes depends on the strength of mitogenic stimulation. Immunol Lett 2016; 171:60-9. [PMID: 26861999 DOI: 10.1016/j.imlet.2016.02.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 01/29/2016] [Accepted: 02/04/2016] [Indexed: 11/15/2022]
Abstract
Ion channels are crucially important for the activation and proliferation of T lymphocytes, and thus, for the function of the immune system. Previous studies on the effects of channel blockers on T cell proliferation reported variable effectiveness due to differing experimental systems. Therefore our aim was to investigate how the strength of the mitogenic stimulation influences the efficiency of cation channel blockers in inhibiting activation, cytokine secretion and proliferation of T cells under standardized conditions. Human peripheral blood lymphocytes were activated via monoclonal antibodies targeting the TCR-CD3 complex and the co-stimulator CD28. We applied the blockers of Kv1.3 (Anuroctoxin), KCa3.1 (TRAM-34) and CRAC (2-Apb) channels of T cells either alone or in combination with rapamycin, the inhibitor of the mammalian target of rapamycin (mTOR). Five days after the stimulation ELISA and flow cytometric measurements were performed to determine IL-10 and IFN-γ secretion, cellular viability and proliferation. Our results showed that ion channel blockers and rapamycin inhibit IL-10 and IFN-γ secretion and cell division in a dose-dependent manner. Simultaneous application of the blockers for each channel along with rapamycin was the most effective, indicating synergy among the various activation pathways. Upon increasing the extent of mitogenic stimulation the anti-proliferative effect of the ion channel blockers diminished. This phenomenon may be important in understanding the fine-tuning of T cell activation.
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Affiliation(s)
- Zoltan Petho
- Department of Biophysics and Cell Biology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary
| | - Andras Balajthy
- Department of Biophysics and Cell Biology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary
| | - Adam Bartok
- Department of Biophysics and Cell Biology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary
| | - Krisztian Bene
- Department of Immunology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary
| | - Sandor Somodi
- 1st Department of Internal Medicine, University of Debrecen, Debrecen, Hungary
| | - Orsolya Szilagyi
- Department of Biophysics and Cell Biology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary
| | - Eva Rajnavolgyi
- Department of Immunology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary
| | - Gyorgy Panyi
- Department of Biophysics and Cell Biology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary.
| | - Zoltan Varga
- Department of Biophysics and Cell Biology, Faculty of General Medicine, University of Debrecen, Debrecen, Hungary; MTA-DE-NAP B Ion Channel Structure-Function Research Group, RCMM, University of Debrecen, Debrecen, Egyetem tér 1, H-4032, Hungary
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Wang K, Mateos-Aparicio P, Hönigsperger C, Raghuram V, Wu WW, Ridder MC, Sah P, Maylie J, Storm JF, Adelman JP. IK1 channels do not contribute to the slow afterhyperpolarization in pyramidal neurons. eLife 2016; 5:e11206. [PMID: 26765773 PMCID: PMC4733036 DOI: 10.7554/elife.11206] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Accepted: 12/01/2015] [Indexed: 11/16/2022] Open
Abstract
In pyramidal neurons such as hippocampal area CA1 and basolateral amygdala, a slow afterhyperpolarization (sAHP) follows a burst of action potentials, which is a powerful regulator of neuronal excitability. The sAHP amplitude increases with aging and may underlie age related memory decline. The sAHP is due to a Ca2+-dependent, voltage-independent K+ conductance, the molecular identity of which has remained elusive until a recent report suggested the Ca2+-activated K+ channel, IK1 (KCNN4) as the sAHP channel in CA1 pyramidal neurons. The signature pharmacology of IK1, blockade by TRAM-34, was reported for the sAHP and underlying current. We have examined the sAHP and find no evidence that TRAM-34 affects either the current underling the sAHP or excitability of CA1 or basolateral amygdala pyramidal neurons. In addition, CA1 pyramidal neurons from IK1 null mice exhibit a characteristic sAHP current. Our results indicate that IK1 channels do not mediate the sAHP in pyramidal neurons. DOI:http://dx.doi.org/10.7554/eLife.11206.001 Neurons carry signals in the form of electrical impulses called action potentials. These nerve impulses result from ions flowing through proteins called ion channels in the neuron’s membrane, and they determine how the neuron communicates with neighboring neurons. The number of action potentials a neuron can produce can vary over a wide range. In the brain, a particular kind of ion channel limits the number of action potentials that many neurons produce via a negative feedback mechanism. That is to say, nerve impulses activate this ion channel and the activated channel then makes the neuron less able to send further nerve impulses for a while.The activity of this ion channel increases with age and it may be responsible for some forms of age-related decline in cognitive abilities. However, the exact identity of the ion channel responsible was unclear. Recent research has suggested the ion channel in question was a protein called IK1. This conclusion was largely based on how this ion channel responded to drugs in the laboratory. Wang, Materos-Aparico et al. sought to verify this conclusion and, in contrast with the previous reports, found that the IK1 ion channel did not respond to these drugs in the same way when it was in neurons in the brains of mice. In further experiments, mice that had been engineered to lack the IK1 ion channel still showed the characteristic negative feedback that regulates the firing of action potentials. Thus, Wang, Materos-Aparico et al. found no evidence to support the previous conclusion, and instead conclude that the exact identity of this important ion channel in the brain has yet to be defined. DOI:http://dx.doi.org/10.7554/eLife.11206.002
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Affiliation(s)
- Kang Wang
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Pedro Mateos-Aparicio
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Christoph Hönigsperger
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Vijeta Raghuram
- Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Wendy W Wu
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, United States
| | - Margreet C Ridder
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Pankaj Sah
- Queensland Brain Institute, The University of Queensland, Brisbane, Australia
| | - Jim Maylie
- Department of Obstetrics and Gynecology, Oregon Health and Science University, Portland, United States
| | - Johan F Storm
- Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - John P Adelman
- Vollum Institute, Oregon Health and Science University, Portland, United States
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48
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Currò D. The Modulation of Potassium Channels in the Smooth Muscle as a Therapeutic Strategy for Disorders of the Gastrointestinal Tract. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2016; 104:263-305. [PMID: 27038377 DOI: 10.1016/bs.apcsb.2015.12.002] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Alterations of smooth muscle contractility contribute to the pathophysiology of important functional gastrointestinal disorders (FGIDs) such as functional dyspepsia and irritable bowel syndrome. Consequently, drugs that decrease smooth muscle contractility are effective treatments for these diseases. Smooth muscle contraction is mainly triggered by Ca(2+) influx through voltage-dependent channels located in the plasma membrane. Thus, the modulation of the membrane potential results in the regulation of Ca(2+) influx and cytosolic levels. K(+) channels play fundamental roles in these processes. The open probability of K(+) channels increases in response to various stimuli, including membrane depolarization (voltage-gated K(+) [K(V)] channels) and the increase in cytosolic Ca(2+) levels (Ca(2+)-dependent K(+) [K(Ca)] channels). K(+) channel activation is mostly associated with outward K(+) currents that hyperpolarize the membrane and reduce cell excitability and contractility. In addition, some K(+) channels are open at the resting membrane potential values of the smooth muscle cells in some gut segments and contribute to set the resting membrane potential itself. The closure of these channels induces membrane depolarization and smooth muscle contraction. K(V)1.2, 1.5, 2.2, 4.3, 7.4 and 11.1, K(Ca)1.1 and 2.3, and inwardly rectifying type 6K(+) (K(ir)6) channels play the most important functional roles in the gastrointestinal smooth muscle. Activators of all these channels may theoretically relax the gastrointestinal smooth muscle and could therefore be promising new therapeutic options for FGID. The challenge of future drug research and development in this area will be to synthesize molecules selective for the channel assemblies expressed in the gastrointestinal smooth muscle.
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Affiliation(s)
- Diego Currò
- Institute of Pharmacology, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy.
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Henríquez C, Riquelme TT, Vera D, Julio-Kalajzić F, Ehrenfeld P, Melvin JE, Figueroa CD, Sarmiento J, Flores CA. The calcium-activated potassium channel KCa3.1 plays a central role in the chemotactic response of mammalian neutrophils. Acta Physiol (Oxf) 2016; 216:132-45. [PMID: 26138196 DOI: 10.1111/apha.12548] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 02/13/2015] [Accepted: 06/24/2015] [Indexed: 12/27/2022]
Abstract
AIM Neutrophils are the first cells to arrive at sites of injury. Nevertheless, many inflammatory diseases are characterized by an uncontrolled infiltration and action of these cells. Cell migration depends on volume changes that are governed by ion channel activity, but potassium channels in neutrophil have not been clearly identified. We aim to test whether KCa3.1 participates in neutrophil migration and other relevant functions of the cell. METHODS Cytometer and confocal measurements to determine changes in cell volume were used. Cells isolated from human, mouse and horse were tested for KCa3.1-dependent chemotaxis. Chemokinetics, calcium handling and release of reactive oxygen species were measured to determine the role of KCa3.1 in those processes. A mouse model was used to test for neutrophil recruitment after acute lung injury in vivo. RESULTS We show for the first time that KCa3.1 is expressed in mammalian neutrophils. When the channel is inhibited by a pharmacological blocker or by genetic silencing, it profoundly affects cell volume regulation, and chemotactic and chemokinetic properties of the cells. We also demonstrated that pharmacological inhibition of KCa3.1 did not affect calcium entry or reactive oxygen species production in neutrophils. Using a mouse model of acute lung injury, we observed that Kca3.1(-/-) mice are significantly less effective at recruiting neutrophils into the site of inflammation. CONCLUSIONS These results demonstrate that KCa3.1 channels are key actors in the migration capacity of neutrophils, and its inhibition did not affect other relevant cellular functions.
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Affiliation(s)
- C. Henríquez
- Instituto de Farmacología; Facultad de Medicina Veterinaria; Universidad Austral de Chile; Valdivia Chile
| | | | - D. Vera
- Centro de Estudios Científicos (CECs); Valdivia Chile
| | - F. Julio-Kalajzić
- Centro de Estudios Científicos (CECs); Valdivia Chile
- Pontificia Universidad Católica de Valparaíso; Valparaíso Chile
| | - P. Ehrenfeld
- Institutos de Anatomía; Histología y Patología; Universidad Austral de Chile; Valdivia Chile
| | - J. E. Melvin
- Secretory Mechanisms and Dysfunction Section; National Institute of Dental and Craniofacial Research; National Institutes of Health; Bethesda MD USA
| | - C. D. Figueroa
- Institutos de Anatomía; Histología y Patología; Universidad Austral de Chile; Valdivia Chile
| | - J. Sarmiento
- Instituto de Fisiología; Facultad de Medicina; Universidad Austral de Chile; Valdivia Chile
| | - C. A. Flores
- Centro de Estudios Científicos (CECs); Valdivia Chile
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50
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Cui CY, Sima J, Yin M, Michel M, Kunisada M, Schlessinger D. Identification of potassium and chloride channels in eccrine sweat glands. J Dermatol Sci 2015; 81:129-31. [PMID: 26627722 DOI: 10.1016/j.jdermsci.2015.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 10/16/2015] [Accepted: 11/04/2015] [Indexed: 11/29/2022]
Affiliation(s)
- Chang-Yi Cui
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd., Suite 100, Baltimore, MD, USA.
| | - Jian Sima
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd., Suite 100, Baltimore, MD, USA
| | - Mingzhu Yin
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd., Suite 100, Baltimore, MD, USA
| | - Marc Michel
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd., Suite 100, Baltimore, MD, USA
| | - Makoto Kunisada
- Division of Dermatology, Department of Internal Related, Graduate School of Medicine, Kobe University, Kobe, Japan
| | - David Schlessinger
- Laboratory of Genetics, National Institute on Aging, National Institutes of Health, 251 Bayview Blvd., Suite 100, Baltimore, MD, USA
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