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TMEM16A as a potential treatment target for head and neck cancer. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2022; 41:196. [PMID: 35668455 PMCID: PMC9172006 DOI: 10.1186/s13046-022-02405-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 05/26/2022] [Indexed: 01/02/2023]
Abstract
Transmembrane protein 16A (TMEM16A) forms a plasma membrane-localized Ca2+-activated Cl- channel. Its gene has been mapped to an area on chromosome 11q13, which is amplified in head and neck squamous cell carcinoma (HNSCC). In HNSCC, TMEM16A overexpression is associated with not only high tumor grade, metastasis, low survival, and poor prognosis, but also deterioration of clinical outcomes following platinum-based chemotherapy. Recent study revealed the interaction between TMEM16A and transforming growth factor-β (TGF-β) has an indirect crosstalk in clarifying the mechanism of TMEM16A-induced epithelial-mesenchymal transition. Moreover, human papillomavirus (HPV) infection can modulate TMEM16A expression along with epidermal growth factor receptor (EGFR), whose phosphorylation has been reported as a potential co-biomarker of HPV-positive cancers. Considering that EGFR forms a functional complex with TMEM16A and is a co-biomarker of HPV, there may be crosstalk between TMEM16A expression and HPV-induced HNSCC. EGFR activation can induce programmed death ligand 1 (PD-L1) synthesis via activation of the nuclear factor kappa B pathway and JAK/STAT3 pathway. Here, we describe an interplay among EGFR, PD-L1, and TMEM16A. Combination therapy using TMEM16A and PD-L1 inhibitors may improve the survival rate of HNSCC patients, especially those resistant to anti-EGFR inhibitor treatment. To the best of our knowledge, this is the first review to propose a biological validation that combines immune checkpoint inhibition with TMEM16A inhibition.
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Hawn MB, Akin E, Hartzell H, Greenwood IA, Leblanc N. Molecular mechanisms of activation and regulation of ANO1-Encoded Ca 2+-Activated Cl - channels. Channels (Austin) 2021; 15:569-603. [PMID: 34488544 PMCID: PMC8480199 DOI: 10.1080/19336950.2021.1975411] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 08/29/2021] [Indexed: 01/13/2023] Open
Abstract
Ca2+-activated Cl- channels (CaCCs) perform a multitude of functions including the control of cell excitability, regulation of cell volume and ionic homeostasis, exocrine and endocrine secretion, fertilization, amplification of olfactory sensory function, and control of smooth muscle cell contractility. CaCCs are the translated products of two members (ANO1 and ANO2, also known as TMEM16A and TMEM16B) of the Anoctamin family of genes comprising ten paralogs. This review focuses on recent progress in understanding the molecular mechanisms involved in the regulation of ANO1 by cytoplasmic Ca2+, post-translational modifications, and how the channel protein interacts with membrane lipids and protein partners. After first reviewing the basic properties of native CaCCs, we then present a brief historical perspective highlighting controversies about their molecular identity in native cells. This is followed by a summary of the fundamental biophysical and structural properties of ANO1. We specifically address whether the channel is directly activated by internal Ca2+ or indirectly through the intervention of the Ca2+-binding protein Calmodulin (CaM), and the structural domains responsible for Ca2+- and voltage-dependent gating. We then review the regulation of ANO1 by internal ATP, Calmodulin-dependent protein kinase II-(CaMKII)-mediated phosphorylation and phosphatase activity, membrane lipids such as the phospholipid phosphatidyl-(4,5)-bisphosphate (PIP2), free fatty acids and cholesterol, and the cytoskeleton. The article ends with a survey of physical and functional interactions of ANO1 with other membrane proteins such as CLCA1/2, inositol trisphosphate and ryanodine receptors in the endoplasmic reticulum, several members of the TRP channel family, and the ancillary Κ+ channel β subunits KCNE1/5.
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Affiliation(s)
- M. B. Hawn
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - E. Akin
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
| | - H.C. Hartzell
- Department of Cell Biology, Emory University School of Medicine, USA
| | - I. A. Greenwood
- Department of Vascular Pharmacology, St. George’s University of London, UK
| | - N. Leblanc
- Department of Pharmacology and Center of Biomedical Research Excellence for Molecular and Cellular Signal Transduction in the Cardiovascular System, University of Nevada, Reno School of Medicine, Reno, United States
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3
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Bai W, Liu M, Xiao Q. The diverse roles of TMEM16A Ca 2+-activated Cl - channels in inflammation. J Adv Res 2021; 33:53-68. [PMID: 34603778 PMCID: PMC8463915 DOI: 10.1016/j.jare.2021.01.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 12/17/2020] [Accepted: 01/24/2021] [Indexed: 12/14/2022] Open
Abstract
Background Transmembrane protein 16A (TMEM16A) Ca2+-activated Cl- channels have diverse physiological functions, such as epithelial secretion of Cl- and fluid and sensation of pain. Recent studies have demonstrated that TMEM16A contributes to the pathogenesis of infectious and non-infectious inflammatory diseases. However, the role of TMEM16A in inflammation has not been clearly elucidated. Aim of review In this review, we aimed to provide comprehensive information regarding the roles of TMEM16A in inflammation by summarizing the mechanisms underlying TMEM16A expression and activation under inflammatory conditions, in addition to exploring the diverse inflammatory signaling pathways activated by TMEM16A. This review attempts to develop the idea that TMEM16A plays a diverse role in inflammatory processes and contributes to inflammatory diseases in a cellular environment-dependent manner. Key scientific concepts of review Multiple inflammatory mediators, including cytokines (e.g., interleukin (IL)-4, IL-13, IL-6), histamine, bradykinin, and ATP/UTP, as well as bacterial and viral infections, promote TMEM16A expression and/or activity under inflammatory conditions. In addition, TMEM16A activates diverse inflammatory signaling pathways, including the IP3R-mediated Ca2+ signaling pathway, the NF-κB signaling pathway, and the ERK signaling pathway, and contributes to the pathogenesis of many inflammatory diseases. These diseases include airway inflammatory diseases, lipopolysaccharide-induced intestinal epithelial barrier dysfunction, acute pancreatitis, and steatohepatitis. TMEM16A also plays multiple roles in inflammatory processes by increasing vascular permeability and leukocyte adhesion, promoting inflammatory cytokine release, and sensing inflammation-induced pain. Furthermore, TMEM16A plays its diverse pathological roles in different inflammatory diseases depending on the disease severity, proliferating status of the cells, and its interacting partners. We herein propose cellular environment-dependent mechanisms that explain the diverse roles of TMEM16A in inflammation.
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Affiliation(s)
- Weiliang Bai
- Department of Otolaryngology Head and Neck Surgery, Shengjing Hospital of China Medical University, Shenyang 110004, China
| | - Mei Liu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, Shenyang 110122, China
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Chang-Graham AL, Perry JL, Engevik MA, Engevik KA, Scribano FJ, Gebert JT, Danhof HA, Nelson JC, Kellen JS, Strtak AC, Sastri NP, Estes MK, Britton RA, Versalovic J, Hyser JM. Rotavirus induces intercellular calcium waves through ADP signaling. Science 2020; 370:370/6519/eabc3621. [PMID: 33214249 PMCID: PMC7957961 DOI: 10.1126/science.abc3621] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Accepted: 10/16/2020] [Indexed: 01/14/2023]
Abstract
Rotavirus causes severe diarrheal disease in children by broadly dysregulating intestinal homeostasis. However, the underlying mechanism(s) of rotavirus-induced dysregulation remains unclear. We found that rotavirus-infected cells produce paracrine signals that manifested as intercellular calcium waves (ICWs), observed in cell lines and human intestinal enteroids. Rotavirus ICWs were caused by the release of extracellular adenosine 5'-diphosphate (ADP) that activated P2Y1 purinergic receptors on neighboring cells. ICWs were blocked by P2Y1 antagonists or CRISPR-Cas9 knockout of the P2Y1 receptor. Blocking the ADP signal reduced rotavirus replication, inhibited rotavirus-induced serotonin release and fluid secretion, and reduced diarrhea severity in neonatal mice. Thus, rotavirus exploited paracrine purinergic signaling to generate ICWs that amplified the dysregulation of host cells and altered gastrointestinal physiology to cause diarrhea.
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Affiliation(s)
- Alexandra L. Chang-Graham
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - Jacob L. Perry
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - Melinda A. Engevik
- Department of Pathology and Immunology, Baylor College of Medicine, USA,Department of Pathology, Texas Children’s Hospital, USA
| | - Kristen A. Engevik
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - Francesca J. Scribano
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - J. Thomas Gebert
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - Heather A. Danhof
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - Joel C. Nelson
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA
| | - Joseph S. Kellen
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - Alicia C. Strtak
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - Narayan P. Sastri
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA
| | - Mary K. Estes
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA,Department of Medicine, Gastroenterology and Hepatology, Baylor College of Medicine, USA
| | - Robert A. Britton
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA
| | - James Versalovic
- Department of Pathology and Immunology, Baylor College of Medicine, USA,Department of Pathology, Texas Children’s Hospital, USA
| | - Joseph M. Hyser
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, USA,Alkek Center for Metagenomic and Microbiome Research, Baylor College of Medicine, USA,Corresponding author. Correspondence and requests for materials should be addressed to J.H.
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Cell death in the gut epithelium and implications for chronic inflammation. Nat Rev Gastroenterol Hepatol 2020; 17:543-556. [PMID: 32651553 DOI: 10.1038/s41575-020-0326-4] [Citation(s) in RCA: 151] [Impact Index Per Article: 37.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/26/2020] [Indexed: 02/06/2023]
Abstract
The intestinal epithelium has one of the highest rates of cellular turnover in a process that is tightly regulated. As the transit-amplifying progenitors of the intestinal epithelium generate ~300 cells per crypt every day, regulated cell death and sloughing at the apical surface keeps the overall cell number in check. An aberrant increase in the rate of intestinal epithelial cell (IEC) death underlies instances of extensive epithelial erosion, which is characteristic of several intestinal diseases such as inflammatory bowel disease and infectious colitis. Emerging evidence points to a crucial role of necroptosis, autophagy and pyroptosis as important modes of programmed cell death in the intestine in addition to apoptosis. The mode of cell death affects tissue restitution responses and ultimately the long-term risks of intestinal fibrosis and colorectal cancer. A vicious cycle of intestinal barrier breach, misregulated cell death and subsequent inflammation is at the heart of chronic inflammatory and infectious gastrointestinal diseases. This Review discusses the underlying molecular and cellular underpinnings that control programmed cell death in IECs, which emerge during intestinal diseases. Translational aspects of cell death modulation for the development of novel therapeutic alternatives for inflammatory bowel diseases and colorectal cancer are also discussed.
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Bleibaum F, Sommer A, Veit M, Rabe B, Andrä J, Kunzelmann K, Nehls C, Correa W, Gutsmann T, Grötzinger J, Bhakdi S, Reiss K. ADAM10 sheddase activation is controlled by cell membrane asymmetry. J Mol Cell Biol 2020; 11:979-993. [PMID: 30753537 PMCID: PMC6927242 DOI: 10.1093/jmcb/mjz008] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 11/20/2018] [Accepted: 02/06/2019] [Indexed: 12/14/2022] Open
Abstract
Dysregulation of the disintegrin-metalloproteinase ADAM10 may contribute to the development of diseases including tumorigenesis and Alzheimer's disease. The mechanisms underlying ADAM10 sheddase activation are incompletely understood. Here, we show that transient exposure of the negatively charged phospholipid phosphatidylserine (PS) is necessarily required. The soluble PS headgroup was found to act as competitive inhibitor of substrate cleavage. Overexpression of the Ca2+-dependent phospholipid scramblase Anoctamin-6 (ANO6) led to increased PS externalization and substrate release. Transfection with a constitutively active form of ANO6 resulted in maximum sheddase activity in the absence of any stimulus. Calcium-dependent ADAM10 activation could not be induced in lymphocytes of patients with Scott syndrome harbouring a missense mutation in ANO6. A putative PS-binding motif was identified in the conserved stalk region. Replacement of this motif resulted in strong reduction of sheddase activity. In conjunction with the recently described 3D structure of the ADAM10 extracellular domain, a model is advanced to explain how surface-exposed PS triggers ADAM10 sheddase function.
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Affiliation(s)
| | - Anselm Sommer
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Martin Veit
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Björn Rabe
- Institute of Biochemistry, University of Kiel, Olshausenstraße 40, Kiel, Germany
| | - Jörg Andrä
- Hamburg University of Applied Science, Ulmenliet 20, Hamburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Universitätsstraße 31, Regensburg, Germany
| | - Christian Nehls
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Parkallee 10, Borstel, Germany
| | - Wilmar Correa
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Parkallee 10, Borstel, Germany
| | - Thomas Gutsmann
- Forschungszentrum Borstel, Leibniz-Zentrum für Medizin und Biowissenschaften, Parkallee 10, Borstel, Germany
| | - Joachim Grötzinger
- Institute of Biochemistry, University of Kiel, Olshausenstraße 40, Kiel, Germany
| | - Sucharit Bhakdi
- Department of Dermatology, University of Kiel, Kiel, Germany
| | - Karina Reiss
- Department of Dermatology, University of Kiel, Kiel, Germany
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Targeting of Intracellular TMEM16 Proteins to the Plasma Membrane and Activation by Purinergic Signaling. Int J Mol Sci 2020; 21:ijms21114065. [PMID: 32517157 PMCID: PMC7312528 DOI: 10.3390/ijms21114065] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 05/31/2020] [Accepted: 06/02/2020] [Indexed: 11/22/2022] Open
Abstract
Anoctamins such as TMEM16A and TMEM16B are Ca2+-dependent Cl− channels activated through purinergic receptor signaling. TMEM16A (ANO1), TMEM16B (ANO2) and TMEM16F (ANO6) are predominantly expressed at the plasma membrane and are therefore well accessible for functional studies. While TMEM16A and TMEM16B form halide-selective ion channels, TMEM16F and probably TMEM16E operate as phospholipid scramblases and nonselective ion channels. Other TMEM16 paralogs are expressed mainly in intracellular compartments and are therefore difficult to study at the functional level. Here, we report that TMEM16E (ANO5), -H (ANO8), -J (ANO9) and K (ANO10) are targeted to the plasma membrane when fused to a C-terminal CAAX (cysteine, two aliphatic amino acids plus methionin, serine, alanin, cystein or glutamin) motif. These paralogs produce Ca2+-dependent ion channels. Surprisingly, expression of the TMEM16 paralogs in the plasma membrane did not produce additional scramblase activity. In contrast, endogenous scrambling induced by stimulation of purinergic P2X7 receptors was attenuated, in parallel with reduced plasma membrane blebbing. This could suggest that intracellular TMEM16 paralogs operate differently when compared to plasma membrane-localized TMEM16F, and may even stabilize intracellular membranes. Alternatively, CAAX tagging, which leads to expression in non-raft compartments of the plasma membrane, may antagonize phosphatidylserine exposure by endogenous raft-located TMEM16F. CAAX-containing constructs may be useful to further investigate the molecular properties of intracellular TMEM16 proteins.
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Park JH, Ousingsawat J, Cabrita I, Bettels RE, Große-Onnebrink J, Schmalstieg C, Biskup S, Reunert J, Rust S, Schreiber R, Kunzelmann K, Marquardt T. TMEM16A deficiency: a potentially fatal neonatal disease resulting from impaired chloride currents. J Med Genet 2020; 58:247-253. [PMID: 32487539 DOI: 10.1136/jmedgenet-2020-106978] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2020] [Revised: 04/14/2020] [Accepted: 04/18/2020] [Indexed: 12/13/2022]
Abstract
INTRODUCTION TMEM16A is a calcium-activated chloride channel expressed in various secretory epithelia. Two siblings presented in early infancy with reduced intestinal peristalsis and recurrent episodes of haemorrhagic diarrhoea. In one of them, the episodes were characterised by hepatic pneumatosis with gas bubbles in the portal vein similar to necrotising enterocolitis of the newborn. METHODS Exome sequencing identified a homozygous truncating pathogenic variant in ANO1. Expression analysis was performed using reverse transcription PCR, western blot and immunohistochemistry. Electrophysiological and cell biological studies were employed to characterise the effects on ion transport both in patient respiratory epithelial cells and in transfected HEK293 cells. RESULTS The identified variant led to TMEM16A dysfunction, which resulted in abolished calcium-activated Cl- currents. Secondarily, CFTR function is affected due to the close interplay between both channels without inducing cystic fibrosis (CF). CONCLUSION TMEM16A deficiency is a potentially fatal disorder caused by abolished calcium-activated Cl- currents in secretory epithelia. Secondary impairment of CFTR function did not cause a CF phenotyp, which may have implications for CF treatment.
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Affiliation(s)
- Julien H Park
- Department of Paediatrics, University Hospital Münster, Münster, Nordrhein-Westfalen, Germany
| | | | - Inês Cabrita
- Department of Physiology, University of Regensburg, Regensburg, Bayern, Germany
| | - Ruth E Bettels
- Department of Paediatrics, University Hospital Münster, Münster, Nordrhein-Westfalen, Germany
| | - Jörg Große-Onnebrink
- Department of Paediatrics, University Hospital Münster, Münster, Nordrhein-Westfalen, Germany
| | - Christian Schmalstieg
- Department of Paediatrics, University Hospital Münster, Münster, Nordrhein-Westfalen, Germany
| | | | - Janine Reunert
- Department of Paediatrics, University Hospital Münster, Münster, Nordrhein-Westfalen, Germany
| | - Stephan Rust
- Department of Paediatrics, University Hospital Münster, Münster, Nordrhein-Westfalen, Germany
| | - Rainer Schreiber
- Department of Physiology, University of Regensburg, Regensburg, Bayern, Germany
| | - Karl Kunzelmann
- Department of Physiology, University of Regensburg, Regensburg, Bayern, Germany
| | - Thorsten Marquardt
- Department of Paediatrics, University Hospital Münster, Münster, Nordrhein-Westfalen, Germany
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Liu PY, Zhang Z, Liu Y, Tang XL, Shu S, Bao XY, Zhang Y, Gu Y, Xu Y, Cao X. TMEM16A Inhibition Preserves Blood-Brain Barrier Integrity After Ischemic Stroke. Front Cell Neurosci 2019; 13:360. [PMID: 31447648 PMCID: PMC6691060 DOI: 10.3389/fncel.2019.00360] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/23/2019] [Indexed: 12/23/2022] Open
Abstract
The inflammatory response plays a pivotal role in Blood–Brain Barrier (BBB) destruction following ischemic brain injury. Enhanced leukocyte adhesion to vascular endothelial cells is an essential event in the inflammatory process. TMEM16A, a newly discovered protein regulating calcium-activated chloride channels, is widely expressed in eukaryotes. Recent studies have suggested that upregulated expression of TMEM16A is associated with the occurrence and development of many diseases. However, the role of TMEM16A in regulating BBB integrity after ischemic stroke has not been fully investigated. In this study, we found that TMEM16A is mainly expressed in brain endothelial cells and upregulated after ischemic stroke in the mouse brain. Caccinh-A01, an TMEM16A inhibitor that reduced its upregulation, attenuated brain infarct size and neurological deficits after ischemic stroke. ICAM-1 and MPO expression and BBB permeability were decreased after TMEM16A inhibitor administration. In addition, TMEM16A silencing rescued oxygen-glucose deprivation/reoxygenation (OGD/R)-induced transendothelial permeability in vitro accompanied by decreased ICAM-1 expression and leukocyte adhesion. Furthermore, our mechanistic study showed that TMEM16A knockdown alleviated NF-κB activation and nuclear translocation, indicating that TMEM16A knockdown downregulated OGD/R-induced ICAM-1 expression in an NF-κB-dependent manner. Finally, NF-κB inhibitor treatment also alleviated OGD/ R-induced BBB permeability, confirming that activated NF-κB and increased ICAM-1 are essential factors involved in ischemia-induced BBB damage. Thus, our research provides a promising treatment strategy against BBB destruction after ischemic stroke, and TMEM16A may become a potential target for the treatment of ischemic stroke.
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Affiliation(s)
- Pin-Yi Liu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Zhi Zhang
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China
| | - Yi Liu
- Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Xue-Lian Tang
- Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Shu Shu
- Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Xin-Yu Bao
- Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Yan Zhang
- Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Yue Gu
- Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China
| | - Yun Xu
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China.,Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
| | - Xiang Cao
- Department of Neurology, Nanjing Drum Tower Hospital Clinical College of Nanjing Medical University, Nanjing, China.,Department of Neurology, Nanjing Drum Tower Hospital, Medical School and The State Key Laboratory of Pharmaceutical Biotechnology, Institute of Brain Science, Nanjing University, Nanjing, China.,Jiangsu Key Laboratory for Molecular Medicine, Nanjing University Medical School, Nanjing, China.,Jiangsu Province Stroke Center for Diagnosis and Therapy, Nanjing, China.,Nanjing Neuropsychiatry Clinic Medical Center, Nanjing, China
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Contribution of Anoctamins to Cell Survival and Cell Death. Cancers (Basel) 2019; 11:cancers11030382. [PMID: 30893776 PMCID: PMC6468699 DOI: 10.3390/cancers11030382] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 03/13/2019] [Accepted: 03/16/2019] [Indexed: 02/07/2023] Open
Abstract
Before anoctamins (TMEM16 proteins) were identified as a family of Ca2+-activated chloride channels and phospholipid scramblases, the founding member anoctamin 1 (ANO1, TMEM16A) was known as DOG1, a marker protein for gastrointestinal stromal tumors (GIST). Meanwhile, ANO1 has been examined in more detail, and the role of ANO1 in cell proliferation and the development of different types of malignomas is now well established. While ANO5, ANO7, and ANO9 may also be relevant for growth of cancers, evidence has been provided for a role of ANO6 (TMEM16F) in regulated cell death. The cellular mechanisms by which anoctamins control cell proliferation and cell death, respectively, are just emerging; however, the pronounced effects of anoctamins on intracellular Ca2+ levels are likely to play a significant role. Recent results suggest that some anoctamins control membrane exocytosis by setting Ca2+i levels near the plasma membrane, and/or by controlling the intracellular Cl- concentration. Exocytosis and increased membrane trafficking induced by ANO1 and ANO6 may enhance membrane expression of other chloride channels, such as CFTR and volume activated chloride channels (VRAC). Notably, ANO6-induced phospholipid scrambling with exposure of phosphatidylserine is pivotal for the sheddase function of disintegrin and metalloproteinase (ADAM). This may support cell death and tumorigenic activity of IL-6 by inducing IL-6 trans-signaling. The reported anticancer effects of the anthelminthic drug niclosamide are probably related to the potent inhibitory effect on ANO1, apart from inducing cell cycle arrest through the Let-7d/CDC34 axis. On the contrary, pronounced activation of ANO6 due to a large increase in intracellular calcium, activation of phospholipase A2 or lipid peroxidation, can lead to ferroptotic death of cancer cells. It therefore appears reasonable to search for both inhibitors and potent activators of TMEM16 in order to interfere with cancer growth and metastasis.
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11
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Okada Y, Okada T, Sato-Numata K, Islam MR, Ando-Akatsuka Y, Numata T, Kubo M, Shimizu T, Kurbannazarova RS, Marunaka Y, Sabirov RZ. Cell Volume-Activated and Volume-Correlated Anion Channels in Mammalian Cells: Their Biophysical, Molecular, and Pharmacological Properties. Pharmacol Rev 2019; 71:49-88. [PMID: 30573636 DOI: 10.1124/pr.118.015917] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
There are a number of mammalian anion channel types associated with cell volume changes. These channel types are classified into two groups: volume-activated anion channels (VAACs) and volume-correlated anion channels (VCACs). VAACs can be directly activated by cell swelling and include the volume-sensitive outwardly rectifying anion channel (VSOR), which is also called the volume-regulated anion channel; the maxi-anion channel (MAC or Maxi-Cl); and the voltage-gated anion channel, chloride channel (ClC)-2. VCACs can be facultatively implicated in, although not directly activated by, cell volume changes and include the cAMP-activated cystic fibrosis transmembrane conductance regulator (CFTR) anion channel, the Ca2+-activated Cl- channel (CaCC), and the acid-sensitive (or acid-stimulated) outwardly rectifying anion channel. This article describes the phenotypical properties and activation mechanisms of both groups of anion channels, including accumulating pieces of information on the basis of recent molecular understanding. To that end, this review also highlights the molecular identities of both anion channel groups; in addition to the molecular identities of ClC-2 and CFTR, those of CaCC, VSOR, and Maxi-Cl were recently identified by applying genome-wide approaches. In the last section of this review, the most up-to-date information on the pharmacological properties of both anion channel groups, especially their half-maximal inhibitory concentrations (IC50 values) and voltage-dependent blocking, is summarized particularly from the standpoint of pharmacological distinctions among them. Future physiologic and pharmacological studies are definitely warranted for therapeutic targeting of dysfunction of VAACs and VCACs.
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Affiliation(s)
- Yasunobu Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Toshiaki Okada
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Kaori Sato-Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Md Rafiqul Islam
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yuhko Ando-Akatsuka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Tomohiro Numata
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Machiko Kubo
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Takahiro Shimizu
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ranohon S Kurbannazarova
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Yoshinori Marunaka
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
| | - Ravshan Z Sabirov
- Departments of Physiology and Systems Bioscience (Y.O.) and Molecular Cell Physiology (Y.M.), Kyoto Prefectural University of Medicine, Kyoto, Japan; Division of Cell Signaling, National Institute for Physiological Sciences, Okazaki, Japan (Y.O., T.O., M.R.I., M.K., R.Z.S.); Department of Physiology, School of Medicine, Fukuoka University, Fukuoka, Japan (K.S.-N., T.N.); Department of Cell Physiology, Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, Suzuka, Japan (Y.A.-A.); Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, Japan (T.S.); Laboratory of Molecular Physiology, Institute of Bioorganic Chemistry, Academy of Sciences of Uzbekistan, Tashkent, Uzbekistan (R.S.K., R.Z.S.); and Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan (Y.M.)
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12
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Veit M, Koyro KI, Ahrens B, Bleibaum F, Munz M, Rövekamp H, Andrä J, Schreiber R, Kunzelmann K, Sommer A, Bhakdi S, Reiss K. Anoctamin-6 regulates ADAM sheddase function. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2018; 1865:1598-1610. [PMID: 30327201 DOI: 10.1016/j.bbamcr.2018.08.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2018] [Revised: 08/17/2018] [Accepted: 08/20/2018] [Indexed: 02/07/2023]
Abstract
ADAM17, a prominent member of the "Disintegrin and Metalloproteinase" (ADAM) family, controls vital cellular functions through cleavage of transmembrane substrates including TGF-alpha, Amphiregulin (AREG) and TNF-Receptor 1 (TNFR1). We recently presented evidence that surface exposure of phosphatidylserine (PS) is pivotal for ADAM17 to exert sheddase activity. Anoctamin-6 (ANO6) has Ca2+-dependent phospholipid scramblase activity and it followed that the functions of ANO6 and ADAM17 might be linked. We report that overexpression of ANO6 in HEK293T cells led to increased Ca2+-mediated PS-exposure that was indeed accompanied by enhanced release of AREG and TGF-alpha. The effect was not observed when cells were treated with the PKC-dependent ADAM17 activator PMA. Transformation of cells with a constitutively active ANO6 mutant led to spontaneous PS-exposure and to the release of ADAM17-substrates in the absence of any stimuli. Inhibitor experiments indicated that ANO6-mediated enhancement of substrate cleavage simultaneously broadened the spectrum of participating metalloproteinases. In complementary experiments, siRNA-mediated downregulation of ANO6 was shown to decrease ionophore-mediated release of TNFR1 in human umbilical vein endothelial cells (HUVECs). We conclude that ANO6, by virtue of its scramblase activity, may play a role as an important regulator of the ADAM-network in the plasma membrane.
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Affiliation(s)
- Martin Veit
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Björn Ahrens
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | | | - Martin Munz
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Hagen Rövekamp
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Jörg Andrä
- Hamburg University of Applied Science, Ulmenliet 20, 21033 Hamburg, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Universitätsstraße 31, 93053 Regensburg, Germany
| | - Anselm Sommer
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Sucharit Bhakdi
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany
| | - Karina Reiss
- Dept. of Dermatology, University of Kiel, 24105 Kiel, Germany.
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13
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Molinski SV, Ahmadi S, Ip W, Ouyang H, Villella A, Miller JP, Lee PS, Kulleperuma K, Du K, Di Paola M, Eckford PD, Laselva O, Huan LJ, Wellhauser L, Li E, Ray PN, Pomès R, Moraes TJ, Gonska T, Ratjen F, Bear CE. Orkambi® and amplifier co-therapy improves function from a rare CFTR mutation in gene-edited cells and patient tissue. EMBO Mol Med 2018; 9:1224-1243. [PMID: 28667089 PMCID: PMC5582412 DOI: 10.15252/emmm.201607137] [Citation(s) in RCA: 83] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The combination therapy of lumacaftor and ivacaftor (Orkambi®) is approved for patients bearing the major cystic fibrosis (CF) mutation: ΔF508. It has been predicted that Orkambi® could treat patients with rarer mutations of similar “theratype”; however, a standardized approach confirming efficacy in these cohorts has not been reported. Here, we demonstrate that patients bearing the rare mutation: c.3700 A>G, causing protein misprocessing and altered channel function—similar to ΔF508‐CFTR, are unlikely to yield a robust Orkambi® response. While in silico and biochemical studies confirmed that this mutation could be corrected and potentiated by lumacaftor and ivacaftor, respectively, this combination led to a minor in vitro response in patient‐derived tissue. A CRISPR/Cas9‐edited bronchial epithelial cell line bearing this mutation enabled studies showing that an “amplifier” compound, effective in increasing the levels of immature CFTR protein, augmented the Orkambi® response. Importantly, this “amplifier” effect was recapitulated in patient‐derived nasal cultures—providing the first evidence for its efficacy in augmenting Orkambi® in tissues harboring a rare CF‐causing mutation. We propose that this multi‐disciplinary approach, including creation of CRISPR/Cas9‐edited cells to profile modulators together with validation using primary tissue, will facilitate therapy development for patients with rare CF mutations.
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Affiliation(s)
- Steven V Molinski
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Saumel Ahmadi
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Wan Ip
- Programme in Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Hong Ouyang
- Programme in Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | | | | | - Po-Shun Lee
- Proteostasis Therapeutics, Cambridge, MA, USA
| | - Kethika Kulleperuma
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Kai Du
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Michelle Di Paola
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Paul Dw Eckford
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Onofrio Laselva
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Ling Jun Huan
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Leigh Wellhauser
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Ellen Li
- Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Peter N Ray
- Division of Molecular Genetics, Hospital for Sick Children, Toronto, ON, Canada
| | - Régis Pomès
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada.,Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada
| | - Theo J Moraes
- Programme in Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Paediatrics, University of Toronto, Toronto, ON, Canada
| | - Tanja Gonska
- Programme in Translational Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Paediatrics, University of Toronto, Toronto, ON, Canada
| | - Felix Ratjen
- Division of Respiratory Medicine, Hospital for Sick Children, Toronto, ON, Canada
| | - Christine E Bear
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada .,Programme in Molecular Medicine, Research Institute, Hospital for Sick Children, Toronto, ON, Canada.,Department of Physiology, University of Toronto, Toronto, ON, Canada
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14
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Sommer N. Anoctamin-1: A Novel Mitochondrial Ion Channel Regulating Cellular Apoptosis and Proliferation? Am J Respir Cell Mol Biol 2018; 58:558-559. [PMID: 29714635 DOI: 10.1165/rcmb.2017-0355ed] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Affiliation(s)
- Natascha Sommer
- 1 German Center for Lung Research Justus Liebig University Giessen, Germany
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15
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Pelz T, Drose DR, Fleck D, Henkel B, Ackels T, Spehr M, Neuhaus EM. An ancestral TMEM16 homolog from Dictyostelium discoideum forms a scramblase. PLoS One 2018; 13:e0191219. [PMID: 29444117 PMCID: PMC5812556 DOI: 10.1371/journal.pone.0191219] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 12/29/2017] [Indexed: 01/11/2023] Open
Abstract
TMEM16 proteins are a recently identified protein family comprising Ca2+-activated Cl- channels that generate outwardly rectifying ionic currents in response to intracellular Ca2+ elevations. Some TMEM16 family members, such as TMEM16F/ANO6 are also essential for Ca2+-dependent phospholipid scrambling. TMEM16-like genes are present in the genomes of most eukaryotic species, the function(s) of TMEM16 family members from evolutionary ancient eukaryotes is not completely clear. Here, we provide insight into the evolution of these TMEM16 proteins by similarity searches for ancestral sequences. All eukaryotic genomes contain TMEM16 homologs, but only vertebrates have the full repertoire of ten distinct subtypes. TMEM16 homologs studied so far belong to the opisthokont branch of the phylogenetic tree, which includes the animal and fungal kingdoms. An organism outside this group is Dictyostelium discoideum, a representative of the amoebozoa group that diverged from the metazoa before fungi. We here functionally investigated the TMEM16 family member from Dictyostelium discoideum. When recombinantly expressed in HEK293 cells, DdTMEM16 induces phospholipid scrambling. However, in several electrophysiological experiments we did not find evidence for a Ca2+-activated Cl- channel function of DdTMEM16.
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Affiliation(s)
- Thomas Pelz
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Daniela R. Drose
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - David Fleck
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Bastian Henkel
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Tobias Ackels
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Marc Spehr
- Department of Chemosensation, Institute for Biology II, RWTH-Aachen University, Aachen, Germany
| | - Eva M. Neuhaus
- Pharmacology and Toxicology, Jena University Hospital, Friedrich Schiller University Jena, Jena, Germany
- Cluster of Excellence NeuroCure, Charité-Universitätsmedizin Berlin, Berlin, Germany
- * E-mail:
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16
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Lérias J, Pinto M, Benedetto R, Schreiber R, Amaral M, Aureli M, Kunzelmann K. Compartmentalized crosstalk of CFTR and TMEM16A (ANO1) through EPAC1 and ADCY1. Cell Signal 2018; 44:10-19. [PMID: 29331508 DOI: 10.1016/j.cellsig.2018.01.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2017] [Revised: 12/11/2017] [Accepted: 01/08/2018] [Indexed: 02/08/2023]
Abstract
Airway epithelial cells express both Ca2+ activated TMEM16A/ANO1 and cAMP activated CFTR anion channels. Previous work suggested a significant crosstalk of intracellular Ca2+ and cAMP signaling pathways, leading to activation of both chloride channels. We demonstrate that in airway epithelial cells, stimulation of purinergic or muscarinic G-protein coupled receptors (GPCRs) activates TMEM16A and CFTR. Additional expression of Gq/11 and phospholipase C coupled GPCRs strongly enhanced the crosstalk between Ca2+- and cAMP-dependent signaling. Knockdown of endogenous GRCRs attenuated crosstalk and functional coupling between TMEM16A and CFTR. The number of receptors did not affect expression or membrane localization of TMEM16A or CFTR, but controlled assembly of the local signalosome. GPCRs translocate Ca2+-sensitive adenylate cyclase type 1 (ADCY1) and exchange protein directly activated by cAMP (EPAC1) to particular plasma membrane domains containing GPCRs, CFTR and TMEM16A, thereby producing compartmentalized Ca2+ and cAMP signals and significant crosstalk. While biosynthesis and membrane trafficking of CFTR requires a functional Golgi apparatus, maturation and membrane trafficking of TMEM16A may occur independent of the Golgi. Because Ca2+ activated TMEM16A currents are only transient, continuous Cl- secretion by airway epithelial cells requires CFTR. The present data also explain why receptor-dependent activation of TMEM16A is more efficient than direct stimulation by Ca2+.
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Affiliation(s)
- Joana Lérias
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal
| | - Madalena Pinto
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal
| | - Roberta Benedetto
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany
| | - Margarida Amaral
- University of Lisboa, Faculty of Sciences, BioISI - Biosystems & Integrative Sciences Institute, Campo Grande, C8, 1749-016 Lisboa, Portugal
| | - Massimo Aureli
- Department of Medical Biotechnology and Translational Medicine, University of Milano, Milano, Italy
| | - Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, D-93053 Regensburg, Germany.
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17
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Stumpff F. A look at the smelly side of physiology: transport of short chain fatty acids. Pflugers Arch 2018; 470:571-598. [PMID: 29305650 DOI: 10.1007/s00424-017-2105-9] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 12/19/2017] [Accepted: 12/20/2017] [Indexed: 12/14/2022]
Abstract
Fermentative organs such as the caecum, the colon, and the rumen have evolved to produce and absorb energy rich short chain fatty acids (SCFA) from otherwise indigestible substrates. Classical models postulate diffusional uptake of the undissociated acid (HSCFA). However, in net terms, a major part of SCFA absorption occurs with uptake of Na+ and resembles classical, coupled electroneutral NaCl transport. Considerable evidence suggests that the anion transporting proteins expressed by epithelia of fermentative organs are poorly selective and that their main function may be to transport acetate-, propionate-, butyrate- and HCO3- as the physiologically relevant anions. Apical uptake of SCFA thus involves non-saturable diffusion of the undissociated acid (HSCFA), SCFA-/HCO3- exchange via DRA (SLC26A3) and/or SCFA--H+ symport (MCT1, SLC16A1). All mechanisms lead to cytosolic acidification with stimulation of Na+/H+ exchange via NHE (SLC9A2/3). Basolaterally, Na+ leaves via the Na+/K+-ATPase with recirculation of K+. Na+ efflux drives the transport of SCFA- anions through volume-regulated anion channels, such as maxi-anion channels (possibly SLCO2A1), LRRC8, anoctamins, or uncoupled exchangers. When luminal buffering is inadequate, basolateral efflux will increasingly involve SCFA-/ HCO3- exchange (AE1/2, SCL4A1/2), or efflux of SCFA- with H+ (MCT1/4, SLC16A1/3). Furthermore, protons can be basolaterally removed by NHE1 (SCL9A1) or NBCe1 (SLC4A4). The purpose of these transport proteins is to maximize the amount of SCFA transported from the tightly buffered ingesta while minimizing acid transport through the epithelium. As known from the rumen for many decades, a disturbance of these processes is likely to cause severe colonic disease.
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Affiliation(s)
- Friederike Stumpff
- Institute of Veterinary Physiology, Department of Veterinary Medicine, Freie Universität Berlin, Oertzenweg 19b, 14163, Berlin, Germany.
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18
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Wang H, Zou L, Ma K, Yu J, Wu H, Wei M, Xiao Q. Cell-specific mechanisms of TMEM16A Ca 2+-activated chloride channel in cancer. Mol Cancer 2017; 16:152. [PMID: 28893247 PMCID: PMC5594453 DOI: 10.1186/s12943-017-0720-x] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 09/01/2017] [Indexed: 02/08/2023] Open
Abstract
TMEM16A (known as anoctamin 1) Ca2+-activated chloride channel is overexpressed in many tumors. TMEM16A overexpression can be caused by gene amplification in many tumors harboring 11q13 amplification. TMEM16A expression is also controlled in many cancer cells via transcriptional regulation, epigenetic regulation and microRNAs. In addition, TMEM16A activates different signaling pathways in different cancers, e.g. the EGFR and CAMKII signaling in breast cancer, the p38 and ERK1/2 signaling in hepatoma, the Ras-Raf-MEK-ERK1/2 signaling in head and neck squamous cell carcinoma and bladder cancer, and the NFκB signaling in glioma. Furthermore, TMEM16A overexpression has been reported to promote, inhibit, or produce no effects on cell proliferation and migration in different cancer cells. Since TMEM16A exerts different roles in different cancer cells via activation of distinct signaling pathways, we try to develop the idea that TMEM16A regulates cancer cell proliferation and migration in a cell-dependent mechanism. The cell-specific role of TMEM16A may depend on the cellular environment that is predetermined by TMEM16A overexpression mechanisms specific for a particular cancer type. TMEM16A may exert its cell-specific role via its associated protein networks, phosphorylation by different kinases, and involvement of different signaling pathways. In addition, we discuss the role of TMEM16A channel activity in cancer, and its clinical use as a prognostic and predictive marker in different cancers. This review highlights the cell-type specific mechanisms of TMEM16A in cancer, and envisions the promising use of TMEM16A inhibitors as a potential treatment for TMEM16A-overexpressing cancers.
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Affiliation(s)
- Hui Wang
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122 China
| | - Liang Zou
- Department of Anesthesiology, National Cancer Center/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100021 China
| | - Ke Ma
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122 China
| | - Jiankun Yu
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122 China
| | - Huizhe Wu
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, 110122 China
| | - Minjie Wei
- Department of Pharmacology, School of Pharmacy, China Medical University, Shenyang, 110122 China
| | - Qinghuan Xiao
- Department of Ion Channel Pharmacology, School of Pharmacy, China Medical University, No.77 Puhe Road, Shenyang North New Area, Shenyang, 110122 China
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19
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Kulkarni S, Bill A, Godse NR, Khan NI, Kass JI, Steehler K, Kemp C, Davis K, Bertrand CA, Vyas AR, Holt DE, Grandis JR, Gaither LA, Duvvuri U. TMEM16A/ANO1 suppression improves response to antibody-mediated targeted therapy of EGFR and HER2/ERBB2. Genes Chromosomes Cancer 2017; 56:460-471. [PMID: 28177558 DOI: 10.1002/gcc.22450] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 12/22/2022] Open
Abstract
TMEM16A, a Ca2+ -activated Cl- channel, contributes to tumor growth in breast cancer and head and neck squamous cell carcinoma (HNSCC). Here, we investigated whether TMEM16A influences the response to EGFR/HER family-targeting biological therapies. Inhibition of TMEM16A Cl- channel activity in breast cancer cells with HER2 amplification induced a loss of viability. Cells resistant to trastuzumab, a monoclonal antibody targeting HER2, showed an increase in TMEM16A expression and heightened sensitivity to Cl- channel inhibition. Treatment of HNSCC cells with cetuximab, a monoclonal antibody targeting EGFR, and simultaneous TMEM16A suppression led to a pronounced loss of viability. Biochemical analyses of cells subjected to TMEM16A inhibitors or expressing chloride-deficient forms of TMEM16A provide further evidence that TMEM16A channel function may play a role in regulating EGFR/HER2 signaling. These data demonstrate that TMEM16A regulates EGFR and HER2 in growth and survival pathways. Furthermore, in the absence of TMEM16A cotargeting, tumor cells may acquire resistance to EGFR/HER inhibitors. Finally, targeting TMEM16A improves response to biological therapies targeting EGFR/HER family members.
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Affiliation(s)
- Sucheta Kulkarni
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.,Veterans Affairs Pittsburgh Health System, Pittsburgh, Pennsylvania
| | - Anke Bill
- Novartis Institute for Biomedical Research, Cambridge, MA, 02139
| | - Neal R Godse
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Nayel I Khan
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Jason I Kass
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Kevin Steehler
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Carolyn Kemp
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.,Veterans Affairs Pittsburgh Health System, Pittsburgh, Pennsylvania
| | - Kara Davis
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Carol A Bertrand
- Department of Cell Biology, University of Pittsburgh, Pittsburgh, Pennsylvania
| | - Avani R Vyas
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Douglas E Holt
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - Jennifer R Grandis
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania
| | - L Alex Gaither
- Novartis Institute for Biomedical Research, Cambridge, MA, 02139
| | - Umamaheswar Duvvuri
- Department of Otolaryngology, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania.,Veterans Affairs Pittsburgh Health System, Pittsburgh, Pennsylvania
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20
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Cabrita I, Benedetto R, Fonseca A, Wanitchakool P, Sirianant L, Skryabin BV, Schenk LK, Pavenstädt H, Schreiber R, Kunzelmann K. Differential effects of anoctamins on intracellular calcium signals. FASEB J 2017; 31:2123-2134. [PMID: 28183802 DOI: 10.1096/fj.201600797rr] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 01/23/2017] [Indexed: 01/04/2023]
Abstract
The Ca2+-activated Cl- channel TMEM16A [anoctamin (ANO)1] is homologous to yeast Ist2 and has been shown to tether the cortical endoplasmic reticulum (ER) to the plasma membrane. We therefore examined whether ANO1 and other members of the ANO family affect intracellular Ca2+ ([Ca2+]i) signals. It is shown that expression of ANO1 augments Ca2+ store release upon stimulation of GPCRs, whereas knockdown of ANO1, or lack of Ano1 expression in Ano1-/- animals, as shown in an earlier report, inhibits Ca2+ release. ANO6, and -10 show similar effects, whereas expression of ANO4, -8, and -9 attenuate filling of the ER store. The impact of ANO1 and -4 were examined in more detail. ANO1 colocalized and interacted with IP3R, whereas ANO4 colocalized with SERCA Ca2+ pumps and interacted with ORAI-1 channels, respectively. ANO1 Cl currents were rapidly activated exclusively through Ca2+ store release, and remained untouched by influx of extracellular Ca2+ In contrast expression of ANO4 caused a delayed activation of membrane-localized ANO6 channels, solely through store-operated Ca2+ entry via ORAI. Ca2+ signals were inhibited by knocking down expression of endogenous ANO1, -5, -6, and -10 and were also reduced in epithelial cells from Ano10-/- mice. The data suggest that ANOs affect compartmentalized [Ca2+]i signals, which may explain some of the cellular defects related to ANO mutations.-Cabrita, I., Benedetto, R., Fonseca, A., Wanitchakool, P., Sirianant, L., Skryabin, B. V., Schenk, L. K., Pavenstädt, H., Schreiber, R., Kunzelmann, K. Differential effects of anoctamins on intracellular calcium signals.
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Affiliation(s)
- Inês Cabrita
- Physiological Institute, University of Regensburg, Regensburg, Germany;
| | - Roberta Benedetto
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Ana Fonseca
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | | | - Lalida Sirianant
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Boris V Skryabin
- Department of Medicine (TRAM), University of Münster, Münster, Germany; and
| | - Laura K Schenk
- Department of Internal Medicine D, Universitätsklinikum Münster, Albert-Schweitzer-Campus, Münster, Germany
| | - Hermann Pavenstädt
- Department of Internal Medicine D, Universitätsklinikum Münster, Albert-Schweitzer-Campus, Münster, Germany
| | - Rainer Schreiber
- Physiological Institute, University of Regensburg, Regensburg, Germany
| | - Karl Kunzelmann
- Physiological Institute, University of Regensburg, Regensburg, Germany;
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21
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Concepcion AR, Feske S. Regulation of epithelial ion transport in exocrine glands by store-operated Ca 2+ entry. Cell Calcium 2016; 63:53-59. [PMID: 28027799 DOI: 10.1016/j.ceca.2016.12.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2016] [Accepted: 12/17/2016] [Indexed: 02/08/2023]
Abstract
Store-operated Ca2+ entry (SOCE) is a conserved mechanism of Ca2+ influx that regulates Ca2+ signaling in many cell types. SOCE is activated by depletion of endoplasmic reticulum (ER) Ca2+ stores in response to physiological agonist stimulation. After it was first postulated by J.W. Putney Jr. in 1986, SOCE has been described in a large number of non-excitable cell types including secretory cells of different exocrine glands. Here we discuss the mechanisms by which SOCE controls salt and fluid secretion in exocrine glands, with a special focus on eccrine sweat glands. In sweat glands, SOCE plays an important, non-redundant role in regulating the function of Ca2+-activated Cl- channels (CaCC), Cl- secretion and sweat production. In the absence of key regulators of SOCE such as the CRAC channel pore subunit ORAI1 and its activator STIM1, the Ca2+-activated chloride channel TMEM16A is inactive and fails to secrete Cl-, resulting in anhidrosis in mice and human patients.
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Affiliation(s)
- Axel R Concepcion
- Department of Pathology, New York University School of Medicine, New York, NY, 10016, USA
| | - Stefan Feske
- Department of Pathology, New York University School of Medicine, New York, NY, 10016, USA.
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22
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Schreiber R, Kunzelmann K. Expression of anoctamins in retinal pigment epithelium (RPE). Pflugers Arch 2016; 468:1921-1929. [PMID: 27822608 DOI: 10.1007/s00424-016-1898-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 10/17/2016] [Accepted: 10/19/2016] [Indexed: 01/24/2023]
Abstract
The anoctamin (ANO, TMEM16) family of Ca2+-activated Cl- channels consists of ten members with different cellular functions (ANO1-10). ANO1 is a Ca2+-activated Cl- channel in secretory epithelial cells of exocrine pancreas, salivary glands, or enterocytes. Expression of ANO1 also promotes cell proliferation and migration of tumor cells. ANO6 is essential for Ca2+-dependent scrambling of membrane phospholipids in platelets, red blood cells, and lymphocytes. ANO10 modulates Ca2+ signals in macrophages and has a role in cerebellar ataxia and other neurological disorders. All three anoctamins have been proposed to control intracellular Ca2+ signals. Anoctamins may also form the basolateral Ca2+-activated Cl- channel in the retinal pigment epithelium (RPE). We show that native human, bovine, porcine, and mouse RPEs express ANO1, ANO6, and ANO10. Growth arrested and confluent RPR cells expressed ANO1 in the plasma membrane, whereas ANO6 and ANO10 were found in the primary cilium. Ussing chamber experiments showed that the application of ATP to the apical (retinal) side of porcine RPE induced a Ca2+-activated Cl- secretion. Activation was inhibited by basolateral (choroidal) administration of the ANO inhibitors AO1, niflumic acid (NFA), and 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS). The results suggest that ANO1 is responsible for basolateral Ca2+-dependent Cl- secretion in RPE, whereas ANO6 and ANO10 may have different functions, such as modulating Ca2+ signals.
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Affiliation(s)
- Rainer Schreiber
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
| | - Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
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23
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Exome sequencing in pooled DNA samples to identify maternal pre-eclampsia risk variants. Sci Rep 2016; 6:29085. [PMID: 27384325 PMCID: PMC4935848 DOI: 10.1038/srep29085] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Accepted: 06/14/2016] [Indexed: 02/04/2023] Open
Abstract
Pre-eclampsia is a common pregnancy disorder that is a major cause for maternal and perinatal mortality and morbidity. Variants predisposing to pre-eclampsia might be under negative evolutionary selection that is likely to keep their population frequencies low. We exome sequenced samples from a hundred Finnish pre-eclamptic women in pools of ten to screen for low-frequency, large-effect risk variants for pre-eclampsia. After filtering and additional genotyping steps, we selected 28 low-frequency missense, nonsense and splice site variants that were enriched in the pre-eclampsia pools compared to reference data, and genotyped the variants in 1353 pre-eclamptic and 699 non-pre-eclamptic women to test the association of them with pre-eclampsia and quantitative traits relevant for the disease. Genotypes from the SISu project (n = 6118 exome sequenced Finnish samples) were included in the binary trait association analysis as a population reference to increase statistical power. In these analyses, none of the variants tested reached genome-wide significance. In conclusion, the genetic risk for pre-eclampsia is likely complex even in a population isolate like Finland, and larger sample sizes will be necessary to detect risk variants.
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24
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Abstract
Activation of ion channels and pores are essential steps during regulated cell death. Channels and pores participate in execution of apoptosis, necroptosis and other forms of caspase-independent cell death. Within the program of regulated cell death, these channels are strategically located. Ion channels can shrink cells and drive them towards apoptosis, resulting in silent, i.e. immunologically unrecognized cell death. Alternatively, activation of channels can induce cell swelling, disintegration of the cell membrane, and highly immunogenic necrotic cell death. The underlying cell death pathways are not strictly separated as identical stimuli may induce cell shrinkage and apoptosis when applied at low strength, but may also cause cell swelling at pronounced stimulation, resulting in regulated necrosis. Nevertheless, the precise role of ion channels during regulated cell death is far from being understood, as identical channels may support regulated death in some cell types, but may cause cell proliferation, cancer development, and metastasis in others. Along this line, the phospholipid scramblase and Cl(-)/nonselective channel anoctamin 6 (ANO6) shows interesting features, as it participates in apoptotic cell death during lower levels of activation, thereby inducing cell shrinkage. At strong activation, e.g. by stimulation of purinergic P2Y7 receptors, it participates in pore formation, causes massive membrane blebbing, cell swelling, and membrane disintegration. The LRRC8 proteins deserve much attention as they were found to have a major role in volume regulation, apoptotic cell shrinkage and resistance towards anticancer drugs.
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Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany.
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25
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Modulating Ca²⁺ signals: a common theme for TMEM16, Ist2, and TMC. Pflugers Arch 2015; 468:475-90. [PMID: 26700940 DOI: 10.1007/s00424-015-1767-4] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/24/2015] [Accepted: 11/26/2015] [Indexed: 12/21/2022]
Abstract
Since the discovery of TMEM16A (anoctamin 1, ANO1) as Ca(2+)-activated Cl(-) channel, the protein was found to serve different physiological functions, depending on the type of tissue. Subsequent reports on other members of the anoctamin family demonstrated a broad range of yet poorly understood properties. Compromised anoctamin function is causing a wide range of diseases, such as hearing loss (ANO2), bleeding disorder (ANO6), ataxia and dystonia (ANO3, 10), persistent borrelia and mycobacteria infection (ANO10), skeletal syndromes like gnathodiaphyseal dysplasia and limb girdle muscle dystrophy (ANO5), and cancer (ANO1, 6, 7). Animal models demonstrate CF-like airway disease, asthma, and intestinal hyposecretion (ANO1). Although present data indicate that ANO1 is a Ca(2+)-activated Cl(-) channel, it remains unclear whether all anoctamins form plasma membrane-localized or intracellular chloride channels. We find Ca(2+)-activated Cl(-) currents appearing by expression of most anoctamin paralogs, including the Nectria haematococca homologue nhTMEM16 and the yeast homologue Ist2. As recent studies show a role of anoctamins, Ist2, and the related transmembrane channel-like (TMC) proteins for intracellular Ca(2+) signaling, we will discuss the role of these proteins in generating compartmentalized Ca(2+) signals, which may give a hint as to the broad range of cellular functions of anoctamins.
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26
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Hoffmann EK, Sørensen BH, Sauter DPR, Lambert IH. Role of volume-regulated and calcium-activated anion channels in cell volume homeostasis, cancer and drug resistance. Channels (Austin) 2015; 9:380-96. [PMID: 26569161 DOI: 10.1080/19336950.2015.1089007] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Volume-regulated channels for anions (VRAC) / organic osmolytes (VSOAC) play essential roles in cell volume regulation and other cellular functions, e.g. proliferation, cell migration and apoptosis. LRRC8A, which belongs to the leucine rich-repeat containing protein family, was recently shown to be an essential component of both VRAC and VSOAC. Reduced VRAC and VSOAC activities are seen in drug resistant cancer cells. ANO1 is a calcium-activated chloride channel expressed on the plasma membrane of e.g., secretory epithelia. ANO1 is amplified and highly expressed in a large number of carcinomas. The gene, encoding for ANO1, maps to a region on chromosome 11 (11q13) that is frequently amplified in cancer cells. Knockdown of ANO1 impairs cell proliferation and cell migration in several cancer cells. Below we summarize the basic biophysical properties of VRAC, VSOAC and ANO1 and their most important cellular functions as well as their role in cancer and drug resistance.
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Affiliation(s)
- Else K Hoffmann
- a Department of Biology ; Section for Cell Biology and Physiology; University of Copenhagen ; Copenhagen , Denmark
| | - Belinda H Sørensen
- a Department of Biology ; Section for Cell Biology and Physiology; University of Copenhagen ; Copenhagen , Denmark
| | - Daniel P R Sauter
- a Department of Biology ; Section for Cell Biology and Physiology; University of Copenhagen ; Copenhagen , Denmark
| | - Ian H Lambert
- a Department of Biology ; Section for Cell Biology and Physiology; University of Copenhagen ; Copenhagen , Denmark
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27
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Cherkashin AP, Kolesnikova AS, Tarasov MV, Romanov RA, Rogachevskaja OA, Bystrova MF, Kolesnikov SS. Expression of calcium-activated chloride channels Ano1 and Ano2 in mouse taste cells. Pflugers Arch 2015; 468:305-19. [DOI: 10.1007/s00424-015-1751-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Revised: 10/20/2015] [Accepted: 10/23/2015] [Indexed: 02/03/2023]
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28
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Strege PR, Bernard CE, Mazzone A, Linden DR, Beyder A, Gibbons SJ, Farrugia G. A novel exon in the human Ca2+-activated Cl- channel Ano1 imparts greater sensitivity to intracellular Ca2. Am J Physiol Gastrointest Liver Physiol 2015; 309:G743-9. [PMID: 26359375 PMCID: PMC4628966 DOI: 10.1152/ajpgi.00074.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 09/06/2015] [Indexed: 01/31/2023]
Abstract
Anoctamin 1 (Ano1; TMEM16A) is a Ca(2+)-activated Cl(-) channel (CACC) expressed in interstitial cells of Cajal. The mechanisms by which Ca(2+) regulates Ano1 are incompletely understood. In the gastrointestinal tract, Ano1 is required for normal slow wave activity and is involved in regulating cell proliferation. Splice variants of Ano1 have varying electrophysiological properties and altered expression in disease states. Recently, we identified a transcript for human Ano1 containing a novel exon-"exon 0" upstream of and in frame with exon 1. The electrophysiological properties of this longer Ano1 isoform are unknown. Our aim was to determine the functional contribution of the newly identified exon to the Ca(2+) sensitivity and electrophysiological properties of Ano1. Constructs with [Ano1(+0)] or without [Ano1(-0)] the newly identified exon were transfected into human embryonic kidney-293 cells. Voltage-clamp electrophysiology was used to determine voltage- and time-dependent parameters of whole cell Cl(-) currents between isoforms with varying concentrations of intracellular Ca(2+), extracellular anions, or Cl(-) channel inhibitors. We found that exon 0 did not change voltage sensitivity and had no impact on the relative permeability of Ano1 to most anions. Ano1(+0) exhibited greater changes in current density but lesser changes in kinetics than Ano1(-0) in response to varying intracellular Ca(2+). The CACC inhibitor niflumic acid inhibited current with greater efficacy and higher potency against Ano1(+0) compared with Ano1(-0). Likewise, the Ano1 inhibitor T16Ainh-A01 reduced Ano1(+0) more than Ano1(-0). In conclusion, human Ano1 containing exon 0 imparts its Cl(-) current with greater sensitivity to intracellular Ca(2+) and CACC inhibitors.
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29
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Chun H, Cho H, Choi J, Lee J, Kim SM, Kim H, Oh U. Protons inhibit anoctamin 1 by competing with calcium. Cell Calcium 2015; 58:431-41. [DOI: 10.1016/j.ceca.2015.06.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Revised: 06/13/2015] [Accepted: 06/28/2015] [Indexed: 01/30/2023]
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30
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Boedtkjer DMB, Kim S, Jensen AB, Matchkov VM, Andersson KE. New selective inhibitors of calcium-activated chloride channels - T16A(inh) -A01, CaCC(inh) -A01 and MONNA - what do they inhibit? Br J Pharmacol 2015; 172:4158-72. [PMID: 26013995 DOI: 10.1111/bph.13201] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 05/12/2015] [Accepted: 05/15/2015] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND AND PURPOSE T16A(inh)-A01, CaCC(inh)-A01 and MONNA are identified as selective inhibitors of the TMEM16A calcium-activated chloride channel (CaCC). The aim of this study was to examine the chloride-specificity of these compounds on isolated resistance arteries in the presence and absence (±) of extracellular chloride. EXPERIMENTAL APPROACH Isolated resistance arteries were maintained in a myograph and tension recorded, in some instances combined with microelectrode impalement for membrane potential measurements or intracellular calcium monitoring using fura-2. Voltage-dependent calcium currents (VDCC) were measured in A7r5 cells with voltage-clamp electrophysiology using barium as a charge carrier. KEY RESULTS Rodent arteries preconstricted with noradrenaline or U46619 were concentration-dependently relaxed by T16A(inh) -A01 (0.1-10 μM): IC50 and maximum relaxation were equivalent in ±chloride (30 min aspartate substitution) and the T16A(inh) -A01-induced vasorelaxation ±chloride were accompanied by membrane hyperpolarization and lowering of intracellular calcium. However, agonist concentration-response curves ±chloride, with 10 μM T16A(inh) -A01 present, achieved similar maximum constrictions although agonist-sensitivity decreased. Contractions induced by elevated extracellular potassium were concentration-dependently relaxed by T16A(inh)-A01 ±chloride. Moreover, T16A(inh) -A01 inhibited VDCCs in A7r5 cells in a concentration-dependent manner. CaCC(inh) -A01 and MONNA (0.1-10 μM) induced vasorelaxation ±chloride and both compounds lowered maximum contractility. MONNA, 10 μM, induced substantial membrane hyperpolarization under resting conditions. CONCLUSIONS AND IMPLICATIONS T16A(inh) -A01, CaCC(inh) -A01 and MONNA concentration-dependently relax rodent resistance arteries, but an equivalent vasorelaxation occurs when the transmembrane chloride gradient is abolished with an impermeant anion. These compounds therefore display poor selectivity for TMEM16A and inhibition of CaCC in vascular tissue in the concentration range that inhibits the isolated conductance.
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Affiliation(s)
- D M B Boedtkjer
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Skejby, Denmark.,Department of Gynaecology and Obstetrics, Aarhus University Hospital, Skejby, Denmark
| | - S Kim
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - A B Jensen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - V M Matchkov
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | - K E Andersson
- Department of Biomedicine, Aarhus University, Aarhus, Denmark.,Department of Gynaecology and Obstetrics, Aarhus University Hospital, Skejby, Denmark.,Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
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31
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Bradley E, Fedigan S, Webb T, Hollywood MA, Thornbury KD, McHale NG, Sergeant GP. Pharmacological characterization of TMEM16A currents. Channels (Austin) 2015; 8:308-20. [PMID: 24642630 DOI: 10.4161/chan.28065] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Recent studies have shown that transmembrane protein 16 A (TMEM16A) is a subunit of calcium-activated chloride channels (CACCs). Pharmacological agents have been used to probe the functional role of CACCs, however their effect on TMEM16A currents has not been systematically investigated. In the present study, we characterized the voltage and concentration-dependent effects of 2 traditional CACC inhibitors (niflumic acid and anthracene-9-carboxcylic acid) and 2 novel CACC / TMEM16A inhibitors (CACC(inh)A01 and T16A(inh)A01) on TMEM16A currents. The whole cell patch clamp technique was used to record TMEM16A currents from HE K 293 cells that stably expressed human TMEM16A. Niflumic acid, A-9-C, CACC(inh)A01 and T16A(inh)A01 inhibited TMEM16A currents with IC50 values of 12, 58, 1.7 and 1.5 μM, respectively, however, A-9-C and niflumic acid were less efficacious at negative membrane potentials. A-9-C and niflumic acid reduced the rate of TMEM16A tail current deactivation at negative membrane potentials and A-9-C (1 mM) enhanced peak TMEM16A tail current amplitude. In contrast, the inhibitory effects of CACC(inh)A01 and T16A(inh)A01 were independent of voltage and they did not prolong the rate of TMEM16A tail current deactivation. The effects of niflumic acid and A-9-C on TMEM16A currents were similar to previous observations on CACCs in vascular smooth muscle, strengthening the hypothesis that they are encoded by TMEM16A. However, CACC(inh)A01 and T16A(inh)A01 were more potent inhibitors of TMEM16A channels and their effects were not diminished at negative membrane potentials making them attractive candidates to interrogate the functional role of TMEM16A channels in future studies.
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Flegel C, Schöbel N, Altmüller J, Becker C, Tannapfel A, Hatt H, Gisselmann G. RNA-Seq Analysis of Human Trigeminal and Dorsal Root Ganglia with a Focus on Chemoreceptors. PLoS One 2015; 10:e0128951. [PMID: 26070209 PMCID: PMC4466559 DOI: 10.1371/journal.pone.0128951] [Citation(s) in RCA: 131] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 05/01/2015] [Indexed: 12/11/2022] Open
Abstract
The chemosensory capacity of the somatosensory system relies on the appropriate expression of chemoreceptors, which detect chemical stimuli and transduce sensory information into cellular signals. Knowledge of the complete repertoire of the chemoreceptors expressed in human sensory ganglia is lacking. This study employed the next-generation sequencing technique (RNA-Seq) to conduct the first expression analysis of human trigeminal ganglia (TG) and dorsal root ganglia (DRG). We analyzed the data with a focus on G-protein coupled receptors (GPCRs) and ion channels, which are (potentially) involved in chemosensation by somatosensory neurons in the human TG and DRG. For years, transient receptor potential (TRP) channels have been considered the main group of receptors for chemosensation in the trigeminal system. Interestingly, we could show that sensory ganglia also express a panel of different olfactory receptors (ORs) with putative chemosensory function. To characterize OR expression in more detail, we performed microarray, semi-quantitative RT-PCR experiments, and immunohistochemical staining. Additionally, we analyzed the expression data to identify further known or putative classes of chemoreceptors in the human TG and DRG. Our results give an overview of the major classes of chemoreceptors expressed in the human TG and DRG and provide the basis for a broader understanding of the reception of chemical cues.
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Affiliation(s)
- Caroline Flegel
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Nicole Schöbel
- Department of Animal Physiology, Ruhr-University Bochum, Bochum, Germany
| | | | | | | | - Hanns Hatt
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
| | - Günter Gisselmann
- Department of Cell Physiology, Ruhr-University Bochum, Bochum, Germany
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Leblanc N, Forrest AS, Ayon RJ, Wiwchar M, Angermann JE, Pritchard HAT, Singer CA, Valencik ML, Britton F, Greenwood IA. Molecular and functional significance of Ca(2+)-activated Cl(-) channels in pulmonary arterial smooth muscle. Pulm Circ 2015; 5:244-68. [PMID: 26064450 DOI: 10.1086/680189] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Accepted: 07/22/2014] [Indexed: 12/31/2022] Open
Abstract
Increased peripheral resistance of small distal pulmonary arteries is a hallmark signature of pulmonary hypertension (PH) and is believed to be the consequence of enhanced vasoconstriction to agonists, thickening of the arterial wall due to remodeling, and increased thrombosis. The elevation in arterial tone in PH is attributable, at least in part, to smooth muscle cells of PH patients being more depolarized and displaying higher intracellular Ca(2+) levels than cells from normal subjects. It is now clear that downregulation of voltage-dependent K(+) channels (e.g., Kv1.5) and increased expression and activity of voltage-dependent (Cav1.2) and voltage-independent (e.g., canonical and vanilloid transient receptor potential [TRPC and TRPV]) Ca(2+) channels play an important role in the functional remodeling of pulmonary arteries in PH. This review focuses on an anion-permeable channel that is now considered a novel excitatory mechanism in the systemic and pulmonary circulations. It is permeable to Cl(-) and is activated by a rise in intracellular Ca(2+) concentration (Ca(2+)-activated Cl(-) channel, or CaCC). The first section outlines the biophysical and pharmacological properties of the channel and ends with a description of the molecular candidate genes postulated to encode for CaCCs, with particular emphasis on the bestrophin and the newly discovered TMEM16 and anoctamin families of genes. The second section provides a review of the various sources of Ca(2+) activating CaCCs, which include stimulation by mobilization from intracellular Ca(2+) stores and Ca(2+) entry through voltage-dependent and voltage-independent Ca(2+) channels. The third and final section summarizes recent findings that suggest a potentially important role for CaCCs and the gene TMEM16A in PH.
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Affiliation(s)
- Normand Leblanc
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Abigail S Forrest
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Ramon J Ayon
- Department of Medicine, University of Illinois, Chicago, Illinois, USA
| | - Michael Wiwchar
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Jeff E Angermann
- School of Community Health Sciences, University of Nevada, Reno, Nevada, USA
| | - Harry A T Pritchard
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St. George's University of London, London, United Kingdom
| | - Cherie A Singer
- Department of Pharmacology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Maria L Valencik
- Department of Biochemistry and Molecular Biology, University of Nevada School of Medicine, Reno, Nevada, USA
| | - Fiona Britton
- Department of Physiology, School of Medical Sciences, University of New South Wales, Sydney, Australia
| | - Iain A Greenwood
- Vascular Biology Research Centre, Institute of Cardiovascular and Cell Sciences, St. George's University of London, London, United Kingdom
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Brune K, Frank J, Schwingshackl A, Finigan J, Sidhaye VK. Pulmonary epithelial barrier function: some new players and mechanisms. Am J Physiol Lung Cell Mol Physiol 2015; 308:L731-45. [PMID: 25637609 DOI: 10.1152/ajplung.00309.2014] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Accepted: 01/27/2015] [Indexed: 12/20/2022] Open
Abstract
The pulmonary epithelium serves as a barrier to prevent access of the inspired luminal contents to the subepithelium. In addition, the epithelium dictates the initial responses of the lung to both infectious and noninfectious stimuli. One mechanism by which the epithelium does this is by coordinating transport of diffusible molecules across the epithelial barrier, both through the cell and between cells. In this review, we will discuss a few emerging paradigms of permeability changes through altered ion transport and paracellular regulation by which the epithelium gates its response to potentially detrimental luminal stimuli. This review is a summary of talks presented during a symposium in Experimental Biology geared toward novel and less recognized methods of epithelial barrier regulation. First, we will discuss mechanisms of dynamic regulation of cell-cell contacts in the context of repetitive exposure to inhaled infectious and noninfectious insults. In the second section, we will briefly discuss mechanisms of transcellular ion homeostasis specifically focused on the role of claudins and paracellular ion-channel regulation in chronic barrier dysfunction. In the next section, we will address transcellular ion transport and highlight the role of Trek-1 in epithelial responses to lung injury. In the final section, we will outline the role of epithelial growth receptor in barrier regulation in baseline, acute lung injury, and airway disease. We will then end with a summary of mechanisms of epithelial control as well as discuss emerging paradigms of the epithelium role in shifting between a structural element that maintains tight cell-cell adhesion to a cell that initiates and participates in immune responses.
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Affiliation(s)
- Kieran Brune
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland
| | - James Frank
- The Division of Pulmonary and Critical Care Medicine, University of California, San Francisco, San Francisco VA Medical Center, and NCIRE/Veterans Health Research Institute, San Francisco, California
| | - Andreas Schwingshackl
- Department of Pediatrics, University of Tennessee Health Science Center, Memphis, Tennessee
| | - James Finigan
- Division of Oncology, Cancer Center, National Jewish Health, Denver, Colorado
| | - Venkataramana K Sidhaye
- Division of Pulmonary and Critical Care Medicine, Johns Hopkins University, Baltimore, Maryland;
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Cherian OL, Menini A, Boccaccio A. Multiple effects of anthracene-9-carboxylic acid on the TMEM16B/anoctamin2 calcium-activated chloride channel. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1005-13. [PMID: 25620774 DOI: 10.1016/j.bbamem.2015.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/04/2015] [Accepted: 01/13/2015] [Indexed: 10/24/2022]
Abstract
Ca(2+)-activated Cl(-) currents (CaCCs) play important roles in many physiological processes. Recent studies have shown that TMEM16A/anoctamin1 and TMEM16B/anoctamin2 constitute CaCCs in several cell types. Here we have investigated for the first time the extracellular effects of the Cl(-) channel blocker anthracene-9-carboxylic acid (A9C) and of its non-charged analogue anthracene-9-methanol (A9M) on TMEM16B expressed in HEK 293T cells, using the whole-cell patch-clamp technique. A9C caused a voltage-dependent block of outward currents and inhibited a larger fraction of the current as depolarization increased, whereas the non-charged A9M produced a small, not voltage dependent block of outward currents. A similar voltage-dependent block by A9C was measured both when TMEM16B was activated by 1.5 and 13μM Ca(2+). However, in the presence of 1.5μM Ca(2+) (but not in 13μM Ca(2+)), A9C also induced a strong potentiation of tail currents measured at -100mV after depolarizing voltages, as well as a prolongation of the deactivation kinetics. On the contrary, A9M did not produce potentiation of tail currents, showing that the negative charge is required for potentiation. Our results provide the first evidence that A9C has multiple effects on TMEM16B and that the negative charge of A9C is necessary both for voltage-dependent block and for potentiation. Future studies are required to identify the molecular mechanisms underlying these complex effects of A9C on TMEM16B. Understanding these mechanisms will contribute to the elucidation of the structure and functional properties of TMEM16B channels.
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Affiliation(s)
- O Lijo Cherian
- Neurobiology Group, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| | - Anna Menini
- Neurobiology Group, SISSA, International School for Advanced Studies, Via Bonomea 265, 34136 Trieste, Italy
| | - Anna Boccaccio
- Istituto di Biofisica, CNR, Via De Marini 6, 16149 Genova, Italy.
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Jin X, Shah S, Du X, Zhang H, Gamper N. Activation of Ca(2+) -activated Cl(-) channel ANO1 by localized Ca(2+) signals. J Physiol 2014; 594:19-30. [PMID: 25398532 PMCID: PMC4704509 DOI: 10.1113/jphysiol.2014.275107] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Accepted: 11/08/2014] [Indexed: 12/13/2022] Open
Abstract
Ca2+‐activated chloride channels (CaCCs) regulate numerous physiological processes including epithelial transport, smooth muscle contraction and sensory processing. Anoctamin‐1 (ANO1, TMEM16A) is a principal CaCC subunit in many cell types, yet our understanding of the mechanisms of ANO1 activation and regulation are only beginning to emerge. Ca2+ sensitivity of ANO1 is rather low and at negative membrane potentials the channel requires several micromoles of intracellular Ca2+ for activation. However, global Ca2+ levels in cells rarely reach such levels and, therefore, there must be mechanisms that focus intracellular Ca2+ transients towards the ANO1 channels. Recent findings indeed indicate that ANO1 channels often co‐localize with sources of intracellular Ca2+ signals. Interestingly, it appears that in many cell types ANO1 is particularly tightly coupled to the Ca2+ release sites of the intracellular Ca2+ stores. Such preferential coupling may represent a general mechanism of ANO1 activation in native tissues.
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Affiliation(s)
- Xin Jin
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Sihab Shah
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK
| | - Xiaona Du
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
| | - Nikita Gamper
- School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds, UK.,Department of Pharmacology, Hebei Medical University, Shijiazhuang, China
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37
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Betto G, Cherian OL, Pifferi S, Cenedese V, Boccaccio A, Menini A. Interactions between permeation and gating in the TMEM16B/anoctamin2 calcium-activated chloride channel. ACTA ACUST UNITED AC 2014; 143:703-18. [PMID: 24863931 PMCID: PMC4035747 DOI: 10.1085/jgp.201411182] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Extracellular anions more permeant than Cl− modulate TMEM16B gating to promote channel opening, whereas less permeant anions favor channel closure. At least two members of the TMEM16/anoctamin family, TMEM16A (also known as anoctamin1) and TMEM16B (also known as anoctamin2), encode Ca2+-activated Cl− channels (CaCCs), which are found in various cell types and mediate numerous physiological functions. Here, we used whole-cell and excised inside-out patch-clamp to investigate the relationship between anion permeation and gating, two processes typically viewed as independent, in TMEM16B expressed in HEK 293T cells. The permeability ratio sequence determined by substituting Cl− with other anions (PX/PCl) was SCN− > I− > NO3− > Br− > Cl− > F− > gluconate. When external Cl− was substituted with other anions, TMEM16B activation and deactivation kinetics at 0.5 µM Ca2+ were modified according to the sequence of permeability ratios, with anions more permeant than Cl− slowing both activation and deactivation and anions less permeant than Cl− accelerating them. Moreover, replacement of external Cl− with gluconate, or sucrose, shifted the voltage dependence of steady-state activation (G-V relation) to more positive potentials, whereas substitution of extracellular or intracellular Cl− with SCN− shifted G-V to more negative potentials. Dose–response relationships for Ca2+ in the presence of different extracellular anions indicated that the apparent affinity for Ca2+ at +100 mV increased with increasing permeability ratio. The apparent affinity for Ca2+ in the presence of intracellular SCN− also increased compared with that in Cl−. Our results provide the first evidence that TMEM16B gating is modulated by permeant anions and provide the basis for future studies aimed at identifying the molecular determinants of TMEM16B ion selectivity and gating.
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Affiliation(s)
- Giulia Betto
- Neurobiology Group, International School for Advanced Studies (SISSA), 34136 Trieste, Italy
| | - O Lijo Cherian
- Neurobiology Group, International School for Advanced Studies (SISSA), 34136 Trieste, Italy
| | - Simone Pifferi
- Neurobiology Group, International School for Advanced Studies (SISSA), 34136 Trieste, Italy
| | - Valentina Cenedese
- Neurobiology Group, International School for Advanced Studies (SISSA), 34136 Trieste, Italy
| | - Anna Boccaccio
- Istituto di Biofisica, Consiglio Nazionale delle Ricerche, 16149 Genova, Italy
| | - Anna Menini
- Neurobiology Group, International School for Advanced Studies (SISSA), 34136 Trieste, Italy
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38
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Domingue JC, Ao M, Sarathy J, George A, Alrefai WA, Nelson DJ, Rao MC. HEK-293 cells expressing the cystic fibrosis transmembrane conductance regulator (CFTR): a model for studying regulation of Cl- transport. Physiol Rep 2014; 2:2/9/e12158. [PMID: 25263207 PMCID: PMC4270233 DOI: 10.14814/phy2.12158] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Human Embryonic Kidney 293 cell line (HEK‐293) readily lends itself to genetic manipulation and is a common tool for biologists to overexpress proteins of interest and study their function and molecular regulation. Although these cells have some limitations, such as an inability to form resistive monolayers necessary for studying transepithelial ion transport, they are nevertheless valuable in studying individual epithelial ion transporters. We report the use of HEK‐293 cells to study the cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel. While HEK‐293 cells endogenously express mRNA for the Cl− channels, ClC‐2 and TMEM16A, they neither express CFTR mRNA nor protein. Therefore, we stably transfected HEK‐293 cells with EGFP‐CFTR (HEK‐CFTR) and demonstrated CFTR function by measuring forskolin‐stimulated iodide efflux. This efflux was inhibited by CFTRinh172, and the protein kinase A inhibitor H89, but not by Ca2+ chelation. In contrast to intestinal epithelia, forskolin stimulation does not increase surface CFTR expression and does not require intact microtubules in HEK‐CFTR. To investigate the role of an endogenous GαS‐coupled receptor, we examined the bile acid receptor, TGR5. Although HEK‐CFTR cells express TGR5, the potent TGR5 agonist lithocholic acid (LCA; 5–500 μmol/L) did not activate CFTR. Furthermore, forskolin, but not LCA, increased [cAMP]i in HEK‐CFTR suggesting that endogenous TGR5 may not be functionally linked to GαS. However, LCA did increase [Ca2+]i and interestingly, abolished forskolin‐stimulated iodide efflux. Thus, we propose that the stable HEK‐CFTR cell line is a useful model to study the multiple signaling pathways that regulate CFTR. In this study, we characterize a HEK‐293 cell line, stably transfected with EGFP‐CFTR (HEK‐CFTR). We examined its regulation by endogenously expressed signaling pathways, in particular the cAMP and the GαS‐coupled bile acid receptor, TGR5, signaling pathways.
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Affiliation(s)
- Jada C Domingue
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Mei Ao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Jayashree Sarathy
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois Department of Biological Sciences, Benedictine University, Lisle, Illinois
| | - Alvin George
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Waddah A Alrefai
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois Jesse Brown V.A. Medical Center, Chicago, Illinois
| | - Deborah J Nelson
- Department of Pharmacological and Physiological Sciences, The University of Chicago, Chicago, Illinois
| | - Mrinalini C Rao
- Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
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39
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Zheng Y, Zhou J, Tong Y. Gene signatures of drug resistance predict patient survival in colorectal cancer. THE PHARMACOGENOMICS JOURNAL 2014; 15:135-43. [PMID: 25179828 PMCID: PMC4381104 DOI: 10.1038/tpj.2014.45] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2014] [Revised: 05/12/2014] [Accepted: 06/25/2014] [Indexed: 01/05/2023]
Abstract
Different combinations of 5-fluorouracil (5-FU), oxaliplatin, irinotecan and other newly developed agents have been used to treat colorectal cancer. Despite the advent of new treatment regimens, the 5-year survival rate for metastatic colorectal cancer remains low (~10%). Knowing the drug sensitivity of a given tumor for a particular agent could significantly impact decision making and treatment planning. Biomarkers are proven to be successful in characterizing patients into different response groups. Using survival prediction analysis, we have identified three independent gene signatures, which are associated with sensitivity of colorectal cancer cells to 5-FU, oxaliplatin or irinotecan. On the basis of the three gene signatures, three score systems were developed to stratify patients from sensitive to resistance. These score systems exhibited robustness in stratify patients in two independent clinical studies. Patients with high scores in all three drugs exhibited the lowest survival.
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Affiliation(s)
- Y Zheng
- 1] Department of Medicine, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA, USA [2] Sun Yat-sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, Guangdong, China
| | - J Zhou
- Division of Epidemiology and Biostatistics, College of Public Health, University of Arizona, Tucson, AZ, USA
| | - Y Tong
- 1] Department of Medicine, Cedars-Sinai Medical Center, UCLA School of Medicine, Los Angeles, CA, USA [2] Department of Pathology, Xinxiang Medical University, Xinxiang, China
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40
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Sauter DRP, Novak I, Pedersen SF, Larsen EH, Hoffmann EK. ANO1 (TMEM16A) in pancreatic ductal adenocarcinoma (PDAC). Pflugers Arch 2014; 467:1495-1508. [PMID: 25163766 PMCID: PMC4464647 DOI: 10.1007/s00424-014-1598-8] [Citation(s) in RCA: 79] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 07/22/2014] [Accepted: 08/11/2014] [Indexed: 12/31/2022]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) has one of the worst survival rates of all cancers. ANO1 (TMEM16A) is a recently identified Ca2+-activated Cl− channel (CaCC) that is upregulated in several tumors. Although ANO1 was subject to extensive studies in the recent years, its pathophysiological function has only been poorly understood. The aim of the present study is to establish the significance of ANO1 in PDAC behavior and demarcate its roles in PDAC from those of the volume-regulated anion channel (VRAC). We performed qPCR and Western blot measurements on different PDAC cell lines (Panc-1, Mia PaCa 2, Capan-1, AsPC-1, BxPC-3) and compared the results to those obtained in a human pancreatic ductal epithelium (HPDE) cell line. All cancer cell lines showed an upregulation of ANO1 on mRNA and protein levels. Whole-cell patch-clamp recordings identified large Ca2+ and voltage-dependent Cl− currents in PDAC cells. Using siRNA knockdown of ANO1 and three ANO1 inhibitors (T16Ainh-A01, CaCCinh-A01, and NS3728), we found that ANO1 is the main constituent of CaCC current in PDAC cells. We further characterized these three inhibitors and found that they had unspecific effects on the free intracellular calcium concentration. Functional studies on PDAC behavior showed that surprisingly inhibition of ANO1 did not influence cellular proliferation. On the other hand, we found ANO1 channel to be pivotal in PDAC cell migration as assessed in wound healing experiments.
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Affiliation(s)
- D R P Sauter
- Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Ø, Denmark.
| | - I Novak
- Section for Molecular Integrative Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100 Copenhagen Ø, Denmark
| | - S F Pedersen
- Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Ø, Denmark
| | - E H Larsen
- Section for Molecular Integrative Physiology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100 Copenhagen Ø, Denmark
| | - E K Hoffmann
- Section for Cell and Developmental Biology, Department of Biology, University of Copenhagen, August Krogh Building, Universitetsparken 13, 2100, Copenhagen Ø, Denmark
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41
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van der Post S, Hansson GC. Membrane protein profiling of human colon reveals distinct regional differences. Mol Cell Proteomics 2014; 13:2277-87. [PMID: 24889196 PMCID: PMC4159649 DOI: 10.1074/mcp.m114.040204] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The colonic epithelium is a highly dynamic system important for the regulation of ion and water homeostasis via absorption and secretion and for the maintenance of a protective barrier between the outer milieu and the inside of the body. These processes are known to gradually change along the length of the colon, although a complete characterization at the protein level is lacking. We therefore analyzed the membrane proteome of isolated human (n = 4) colonic epithelial cells from biopsies obtained via routine colonoscopy for four segments along the large intestine: ascending, transverse, descending, and sigmoid colon. Label-free quantitative proteomic analyses using high-resolution mass spectrometry were performed on enriched membrane proteins. The results showed a stable level for the majority of membrane proteins but a distinct decrease in proteins associated with bacterial sensing, cation transport, and O-glycosylation in the proximal to distal regions. In contrast, proteins involved in microbial defense and anion transport showed an opposing gradient and increased toward the distal end. The gradient of ion-transporter proteins could be directly related to previously observed ion transport activities. All individual glycosyltransferases required for the O-glycosylation of the major colonic mucin MUC2 were observed and correlated with the known glycosylation variation along the colon axis. This is the first comprehensive quantitative dataset of membrane protein abundance along the human colon and will add to the knowledge of the physiological function of the different regions of the colonic mucosa. Mass spectrometry data have been deposited to the ProteomeXchange with the identifier PXD000987.
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Affiliation(s)
- Sjoerd van der Post
- From the ‡Department of Medical Biochemistry, University of Gothenburg, Box 440, 405 30 Gothenburg, Sweden
| | - Gunnar C Hansson
- From the ‡Department of Medical Biochemistry, University of Gothenburg, Box 440, 405 30 Gothenburg, Sweden
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42
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Hoffmann EK, Holm NB, Lambert IH. Functions of volume-sensitive and calcium-activated chloride channels. IUBMB Life 2014; 66:257-67. [PMID: 24771413 DOI: 10.1002/iub.1266] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Revised: 03/31/2014] [Accepted: 03/31/2014] [Indexed: 01/23/2023]
Abstract
The review describes molecular and functional properties of the volume regulated anion channel and Ca(2+)-dependent Cl(-) channels belonging to the anoctamin family with emphasis on physiological importance of these channels in regulation of cell volume, cell migration, cell proliferation, and programmed cell death. Finally, we discuss the role of Cl(-) channels in various diseases.
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Affiliation(s)
- Else Kay Hoffmann
- Department of Biology, University of Copenhagen, 13 Universitetsparken, Copenhagen Ø, Denmark
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43
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Abstract
TMEM16 proteins, also known as anoctamins, are involved in a variety of functions that include ion transport, phospholipid scrambling, and regulation of other membrane proteins. The first two members of the family, TMEM16A (anoctamin-1, ANO1) and TMEM16B (anoctamin-2, ANO2), function as Ca2+-activated Cl- channels (CaCCs), a type of ion channel that plays important functions such as transepithelial ion transport, smooth muscle contraction, olfaction, phototransduction, nociception, and control of neuronal excitability. Genetic ablation of TMEM16A in mice causes impairment of epithelial Cl- secretion, tracheal abnormalities, and block of gastrointestinal peristalsis. TMEM16A is directly regulated by cytosolic Ca2+ as well as indirectly by its interaction with calmodulin. Other members of the anoctamin family, such as TMEM16C, TMEM16D, TMEM16F, TMEM16G, and TMEM16J, may work as phospholipid scramblases and/or ion channels. In particular, TMEM16F (ANO6) is a major contributor to the process of phosphatidylserine translocation from the inner to the outer leaflet of the plasma membrane. Intriguingly, TMEM16F is also associated with the appearance of anion/cation channels activated by very high Ca2+ concentrations. Furthermore, a TMEM16 protein expressed in Aspergillus fumigatus displays both ion channel and lipid scramblase activity. This finding suggests that dual function is an ancestral characteristic of TMEM16 proteins and that some members, such as TMEM16A and TMEM16B, have evolved to a pure channel function. Mutations in anoctamin genes (ANO3, ANO5, ANO6, and ANO10) cause various genetic diseases. These diseases suggest the involvement of anoctamins in a variety of cell functions whose link with ion transport and/or lipid scrambling needs to be clarified.
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44
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Kunzelmann K, Nilius B, Owsianik G, Schreiber R, Ousingsawat J, Sirianant L, Wanitchakool P, Bevers EM, Heemskerk JWM. Molecular functions of anoctamin 6 (TMEM16F): a chloride channel, cation channel, or phospholipid scramblase? Pflugers Arch 2014; 466:407-14. [PMID: 23748496 DOI: 10.1007/s00424-013-1305-1] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 05/27/2013] [Accepted: 05/28/2013] [Indexed: 10/26/2022]
Abstract
Anoctamin 6 (Ano6; TMEM16F gene) is a ubiquitous protein; the expression of which is defective in patients with Scott syndrome, an inherited bleeding disorder based on defective scrambling of plasma membrane phospholipids. For Ano6, quite diverse functions have been described: (1) it can form an outwardly rectifying, Ca(2+)-dependent and a volume-regulated Cl(-) channel; (2) it was claimed to be a Ca(2+)-regulated nonselective cation channel permeable for Ca(2+); (3) it was shown to be essential for Ca(2+)-mediated scrambling of membrane phospholipids; and (4) it can regulate cell blebbing and microparticle shedding. Deficiency of Ano6 in blood cells from Scott patients or Ano6 null mice appears to affect all of these cell responses. Furthermore, Ano6 deficiency in mice impairs the mineralization of osteoblasts, resulting in reduced skeletal development. These diverse results have been obtained under different experimental conditions, which may explain some of the contradictions. This review therefore aims to summarize the currently available information on the diverse roles of Ano6 and tries to clear up some of the existing controversies.
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Affiliation(s)
- Karl Kunzelmann
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany,
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Grubb S, Poulsen KA, Juul CA, Kyed T, Klausen TK, Larsen EH, Hoffmann EK. TMEM16F (Anoctamin 6), an anion channel of delayed Ca(2+) activation. ACTA ACUST UNITED AC 2014; 141:585-600. [PMID: 23630341 PMCID: PMC3639583 DOI: 10.1085/jgp.201210861] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Members of the TMEM16 (Anoctamin) family of membrane proteins have been shown to be essential constituents of the Ca2+-activated Cl− channel (CaCC) in many cell types. In this study, we have investigated the electrophysiological properties of mouse TMEM16F. Heterologous expression of TMEM16F in HEK293 cells resulted in plasma membrane localization and an outwardly rectifying ICl,Ca that was activated with a delay of several minutes. Furthermore, a significant Na+ current was activated, and the two permeabilities were correlated according to PNa = 0.3 PCl. The current showed an EC50 of 100 µM intracellular free Ca2+ concentration and an Eisenman type 1 anion selectivity sequence of PSCN > PI > PBr > PCl > PAsp. The mTMEM16F-associated ICl,Ca was abolished in one mutant of the putative pore region (R592E) but retained in two other mutants (K616E and R636E). The mutant K616E had a lower relative permeability to iodide, and the mutant R636E had an altered anion selectivity sequence (PSCN = PI = PBr = PCl > PAsp). Our data provide evidence that TMEM16F constitutes a Ca2+-activated anion channel or a pore-forming subunit of an anion channel with properties distinct from TMEM16A.
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Affiliation(s)
- Søren Grubb
- Department of Biology, University of Copenhagen, DK-2100 Copenhagen Ø, Denmark
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Anoctamin 6 differs from VRAC and VSOAC but is involved in apoptosis and supports volume regulation in the presence of Ca2+. Pflugers Arch 2014; 466:1899-910. [PMID: 24419539 PMCID: PMC4159566 DOI: 10.1007/s00424-013-1428-4] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Revised: 12/17/2013] [Accepted: 12/19/2013] [Indexed: 10/25/2022]
Abstract
Anoctamin 6 (ANO6), also known as TMEM16F, has been shown to be a calcium-activated anion channel with delayed calcium activation. The cellular function of ANO6 is under debate, and different groups have come to different conclusions about ANO6's physiological role. Although it is now quite well established that ANO6 is distinct from the volume-regulated anion channel, it is still unclear whether ANO6 or other anoctamins can be activated by cell swelling. In this study, we suggest that ANO1, ANO6, and ANO10 do not contribute to the volume-activated current in ANO-overexpressing HEK293 cells. Furthermore, knock-down of ANO6 in Ehrlich ascites tumor cells (EATC) and Ehrlich-Lettre ascites (ELA) did not decrease but instead significantly increased swelling-activated membrane currents. Knock-down of ANO6 in EATC did not reduce regulatory volume decrease (RVD) in the absence of extracellular calcium, whereas it significantly reduced RVD in the presence of calcium. Interestingly, we found that knock-down of ANO6 in ELA cells resulted in a decrease in cisplatin-induced caspase-3 activity, confirming earlier findings that ANO6 is involved in apoptosis. Finally, knock-down of ANO1 and ANO6 did not affect the volume-sensitive release of taurine in ELA cells. Thus, our data provide evidence that ANO6 cannot be activated directly by cell swelling unless Ca(2+) is present. We also conclude that ANO6 carries a current during RVD, provided extracellular calcium is present. Thus, swelling activation of ANO6 requires the presence of free calcium.
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Wang Y, Alam T, Hill-Harfe K, Lopez AJ, Leung CK, Iribarne D, Bruggeman B, Miyamoto MM, Harfe BD, Choe KP. Phylogenetic, expression, and functional analyses of anoctamin homologs in Caenorhabditis elegans. Am J Physiol Regul Integr Comp Physiol 2013; 305:R1376-89. [DOI: 10.1152/ajpregu.00303.2012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ca2+-activated Cl− channels (CaCCs) are critical to processes such as epithelial transport, membrane excitability, and signal transduction. Anoctamin, or TMEM16, is a family of 10 mammalian transmembrane proteins, 2 of which were recently shown to function as CaCCs. The functions of other family members have not been firmly established, and almost nothing is known about anoctamins in invertebrates. Therefore, we performed a phylogenetic analysis of anoctamins across the animal kingdom and examined the expression and function of anoctamins in the genetically tractable nematode Caenorhabditis elegans. Phylogenetic analyses support five anoctamin clades that are at least as old as the deuterostome/protosome ancestor. This includes a branch containing two Drosophila paralogs that group with mammalian ANO1 and ANO2, the two best characterized CaCCs. We identify two anoctamins in C. elegans (ANOH-1 and ANOH-2) that are also present in basal metazoans. The anoh-1 promoter is active in amphid sensory neurons that detect external chemical and nociceptive cues. Within amphid neurons, ANOH-1::GFP fusion protein is enriched within sensory cilia. RNA interference silencing of anoh-1 reduced avoidance of steep osmotic gradients without disrupting amphid cilia development, chemotaxis, or withdrawal from noxious stimuli, suggesting that ANOH-1 functions in a sensory mode-specific manner. The anoh-2 promoter is active in mechanoreceptive neurons and the spermatheca, but loss of anoh-2 had no effect on motility or brood size. Our study indicates that at least five anoctamin duplicates are evolutionarily ancient and suggests that sensory signaling may be a basal function of the anoctamin protein family.
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Affiliation(s)
- Ying Wang
- Department of Biology, University of Florida, Gainesville, Florida
| | - Tashrique Alam
- Department of Biology, University of Florida, Gainesville, Florida
| | | | | | - Chi K. Leung
- Department of Biology, University of Florida, Gainesville, Florida
| | - Daniela Iribarne
- Department of Microbiology and Molecular Genetics, University of Florida, Gainesville, Florida; and
| | - Bradley Bruggeman
- Department of Microbiology and Molecular Genetics, University of Florida, Gainesville, Florida; and
| | | | - Brian D. Harfe
- Department of Microbiology and Molecular Genetics, University of Florida, Gainesville, Florida; and
- Genetics Institute, University of Florida, Gainesville, Florida
| | - Keith P. Choe
- Department of Biology, University of Florida, Gainesville, Florida
- Genetics Institute, University of Florida, Gainesville, Florida
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Kmit A, van Kruchten R, Ousingsawat J, Mattheij NJA, Senden-Gijsbers B, Heemskerk JWM, Schreiber R, Bevers EM, Kunzelmann K. Calcium-activated and apoptotic phospholipid scrambling induced by Ano6 can occur independently of Ano6 ion currents. Cell Death Dis 2013; 4:e611. [PMID: 23618909 PMCID: PMC3668637 DOI: 10.1038/cddis.2013.135] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Revised: 02/16/2013] [Accepted: 03/11/2013] [Indexed: 11/17/2022]
Abstract
Immune cells and platelets maintain plasma membrane phospholipid asymmetry. Upon activation, this asymmetry is disrupted by phospholipid scrambling (PS), which is a major step during activation of immune cells, hemostasis and apoptosis. Anoctamin 6 (Ano6; TMEM16F) causes chloride (Cl(-)) and cation currents and is required for Ca(2+)-dependent PS. It is defective in blood cells from patients with Scott syndrome, a rare bleeding disorder. We examined if Cl(-) currents and PS are related, whether both processes are Ca(2+) dependent, and whether Ca(2+)-independent scrambling during intrinsic and extrinsic apoptosis is controlled by Ano6. Ca(2+) increase by ionomycin activated Ano6 Cl(-) currents and PS in normal lymphocytes, but not in B-lymphocytes from two different patients with Scott syndrome. Fas ligand (FasL) did not increase intracellular Ca(2+), but activated Cl(-) currents in normal but not in Scott lymphocytes. Whole-cell currents were inhibited by Cl(-) channel blockers and by siRNA knockdown of Ano6. In contrast, intrinsic mitochondrial apoptosis by ABT-737 did not induce Cl(-) currents in lymphocytes. PS was not inhibited by blockers of Ano6 or removal of Cl(-) ions. Remarkably, Ca(2+)-independent scrambling due to extrinsic (FasL) or intrinsic (ABT-737) apoptosis was unchanged in Scott cells. We conclude that: (i) Ano6 Cl(-) currents are activated by increase in cytosolic Ca(2+), or Ca(2+) independent by stimulation of Fas receptors; (ii) Ca(2+)-dependent PS induced by Ano6 does not require Cl(-) currents; (iii) Ca(2+)-independent PS does not require Ano6; (iv) Ano6 is necessary for Ca(2+)-dependent PS, but not by increasing intracellular Ca(2+).
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Affiliation(s)
- A Kmit
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - R van Kruchten
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - J Ousingsawat
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - N J A Mattheij
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - B Senden-Gijsbers
- Department of Internal Medicine, Division of Haematology, Maastricht University Medical Center, Maastricht, The Netherlands
| | - J W M Heemskerk
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - R Schreiber
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
| | - E M Bevers
- Department of Biochemistry, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University, Maastricht, The Netherlands
| | - K Kunzelmann
- Institut für Physiologie, Universität Regensburg, Regensburg, Germany
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Adomaviciene A, Smith KJ, Garnett H, Tammaro P. Putative pore-loops of TMEM16/anoctamin channels affect channel density in cell membranes. J Physiol 2013; 591:3487-505. [PMID: 23613533 DOI: 10.1113/jphysiol.2013.251660] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The recently identified TMEM16/anoctamin protein family includes Ca(2+)-activated anion channels (TMEM16A, TMEM16B), a cation channel (TMEM16F) and proteins with unclear function. TMEM16 channels consist of eight putative transmembrane domains (TMs) with TM5-TM6 flanking a re-entrant loop thought to form the pore. In TMEM16A this region has also been suggested to contain residues involved in Ca(2+) binding. The role of the putative pore-loop of TMEM16 channels was investigated using a chimeric approach. Heterologous expression of either TMEM16A or TMEM16B resulted in whole-cell anion currents with very similar conduction properties but distinct kinetics and degrees of sensitivity to Ca(2+). Furthermore, whole-cell currents mediated by TMEM16A channels were ∼six times larger than TMEM16B-mediated currents. Replacement of the putative pore-loop of TMEM16A with that of TMEM16B (TMEM16A-B channels) reduced the currents by ∼six-fold, while the opposite modification (TMEM16B-A channels) produced a ∼six-fold increase in the currents. Unexpectedly, these changes were not secondary to variations in channel gating by Ca(2+) or voltage, nor were they due to changes in single-channel conductance. Instead, they depended on the number of functional channels present on the plasma membrane. Generation of additional, smaller chimeras within the putative pore-loop of TMEM16A and TMEM16B led to the identification of a region containing a non-canonical trafficking motif. Chimeras composed of the putative pore-loop of TMEM16F transplanted into the TMEM16A protein scaffold did not conduct anions or cations. These data suggest that the putative pore-loop does not form a complete, transferable pore domain. Furthermore, our data reveal an unexpected role for the putative pore-loop of TMEM16A and TMEM16B channels in the control of the whole-cell Ca(2+)-activated Cl(-) conductance.
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Affiliation(s)
- Aiste Adomaviciene
- Faculty of Life Sciences, The University of Manchester, 46 Grafton Street, Manchester M13 9NT, UK
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Schwab A, Fabian A, Hanley PJ, Stock C. Role of ion channels and transporters in cell migration. Physiol Rev 2013; 92:1865-913. [PMID: 23073633 DOI: 10.1152/physrev.00018.2011] [Citation(s) in RCA: 311] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Cell motility is central to tissue homeostasis in health and disease, and there is hardly any cell in the body that is not motile at a given point in its life cycle. Important physiological processes intimately related to the ability of the respective cells to migrate include embryogenesis, immune defense, angiogenesis, and wound healing. On the other side, migration is associated with life-threatening pathologies such as tumor metastases and atherosclerosis. Research from the last ≈ 15 years revealed that ion channels and transporters are indispensable components of the cellular migration apparatus. After presenting general principles by which transport proteins affect cell migration, we will discuss systematically the role of channels and transporters involved in cell migration.
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