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Stölting G, Scholl UI. Adrenal Anion Channels: New Roles in Zona Glomerulosa Physiology and in the Pathophysiology of Primary Aldosteronism. Handb Exp Pharmacol 2024; 283:59-79. [PMID: 37495852 DOI: 10.1007/164_2023_680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/28/2023]
Abstract
The mineralocorticoid aldosterone is produced in the zona glomerulosa of the adrenal cortex. Its synthesis is regulated by the serum concentrations of the peptide hormone angiotensin II and potassium. The primary role of aldosterone is to control blood volume and electrolytes. The autonomous production of aldosterone (primary aldosteronism, PA) is considered the most frequent cause of secondary hypertension. Aldosterone-producing adenomas and (micro-)nodules are frequent causes of PA and often carry somatic mutations in ion channels and transporters. Rare familial forms of PA are due to germline mutations. Both somatic and germline mutations in the chloride channel gene CLCN2, encoding ClC-2, have been identified in PA. Clinical findings and results from cell culture and animal models have advanced our knowledge about the role of anions in PA. The zona glomerulosa of the adrenal gland has now been firmly established as a tissue in which anions play a significant role for signaling. In this overview, we aim to summarize the current knowledge and highlight novel concepts as well as open questions.
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Affiliation(s)
- Gabriel Stölting
- Center of Functional Genomics, Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Ute I Scholl
- Center of Functional Genomics, Berlin Institute of Health at Charité - Universitätsmedizin Berlin, Berlin, Germany.
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2
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Linsdell P. Role of Hydrophobic Amino-Acid Side-Chains in the Narrow Selectivity Filter of the CFTR Chloride Channel Pore in Conductance and Selectivity. J Membr Biol 2023; 256:433-442. [PMID: 37823914 DOI: 10.1007/s00232-023-00294-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023]
Abstract
Cystic fibrosis is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) anion channel. Structural analysis of CFTR has identified a narrow, hydrophobic region close to the extracellular end of the open channel pore that may function as a selectivity filter. The present study combines comprehensive mutagenesis of hydrophobic amino-acid side-chains within the selectivity filter with functional evaluation of channel Cl- conductance and anion selectivity. Among these hydrophobic amino-acids, one (F337) appears to play a dominant role in determining both conductance and selectivity. Anion selectivity appears to depend on both side-chain size and hydrophobicity at this position. In contrast, conductance is disrupted by all F337 mutations, suggesting that unique interactions between permeating Cl- ions and the native phenylalanine side-chain are important for conductance. Surprisingly, a positively charged lysine side-chain can be substituted for several hydrophobic residues within the selectivity filter (including F337) with only minor changes in pore function, arguing against a crucial role for overall hydrophobicity. These results suggest that localized interactions between permeating anions and amino-acid side-chains within the selectivity filter may be more important in determining pore functional properties than are global features such as overall hydrophobicity.
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Affiliation(s)
- Paul Linsdell
- Department of Physiology & Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada.
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3
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Eisenhut M. Rhinorrhea and increased chloride secretion through the CFTR chloride channel-a systematic review. Eur Arch Otorhinolaryngol 2023; 280:4309-4318. [PMID: 37338585 DOI: 10.1007/s00405-023-08067-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2023] [Accepted: 06/12/2023] [Indexed: 06/21/2023]
Abstract
PURPOSE Allergic and non-allergic rhinorrhea in the forms of acute or chronic rhinosinusitis can mean a watery nasal discharge that is disabling. Primary objective was to review the evidence supporting the hypothesis that rhinorrhea is due to increased chloride secretion through the CFTR chloride channel. METHODS The structure of the evidence review followed the EQUATOR Reporting Guidelines. Databases searched from inception to February 2022 included Pubmed, EMBASE and the Cochrane library using keywords "Rhinorrhea", "chloride", "chloride channel", "CFTR" and "randomized controlled trial". Quality assessment was according to the Oxford Centre for Evidence-based Medicine. RESULTS 49 articles were included. They included randomized controlled trials out of which subsets of data with the outcome of rhinorrhea on 6038 participants were analysed and in vitro and animal studies. The review revealed that drugs, which activate CFTR are associated with rhinorrhea. Viruses, which cause rhinorrhea like rhinovirus were found to activate CFTR. The chloride concentration in nasal fluid showed an increase in patients with viral upper respiratory tract infection. Increased hydrostatic tissue pressure, which is an activator of CFTR was observed in allergic upper airway inflammation. In this condition exhaled breath condensate chlorine concentration was found to be significantly increased. Drugs, which can reduce CFTR function including steroids, anti-histamines, sympathomimetic and anticholinergic drugs reduced rhinorrhea in randomized controlled trials. CONCLUSIONS A model of CFTR activation-mediated rhinorrhea explains the effectiveness of anticholinergic, sympathomimetic, anti-histamine and steroid drugs in reducing rhinorrhea and opens up avenues for further improvement of treatment by already known specific CFTR inhibitors.
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Affiliation(s)
- Michael Eisenhut
- Paediatric Department, Luton and Dunstable University Hospital, Luton, LU40DZ, UK.
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4
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Zhan E, Jiang J, Wang Y, Zhang K, Tang T, Chen Y, Jia Z, Wang Q, Zhao C. Shisa reduces the sensitivity of homomeric RDL channel to GABA in the two-spotted spider mite, Tetranychus urticae Koch. Pestic Biochem Physiol 2023; 192:105414. [PMID: 37105623 DOI: 10.1016/j.pestbp.2023.105414] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 03/08/2023] [Accepted: 03/28/2023] [Indexed: 06/19/2023]
Abstract
The γ-aminobutyric acid receptors (GABARs) mediate fast inhibitory transmission in central nervous system of insects and are important targets of insecticides. An auxiliary subunit, Shisa7, was identified in mammals as a single-passing transmembrane protein. However, the homology gene(s) of Shisa in invertebrates has not been reported to date. In the present study, a homolog Shisa gene was identified from the two-spotted spider mite, Tetranychus urticae Koch. Its open reading frame had 927 base pairs and encoded 308 amino acid residues, which has a typical Shisa domain at 13th-181st amino acid residues. According to the phylogenetic tree, the invertebrate Shisa was categorized apart with those of vertebrate, and TuShisa showed closest relationship with the Shisa9 of velvet mite, Dinothrombium tinctorium (L.). In the electrophysiological assay with two-electrode voltage clamp, the GABA-activated TuRDL channel was functionally formed in the Africa clawed frog Xenopus laevis (Daudin) oocytes (EC50 = 53.34 μM). No GABA-activated current could be observed in TuShisa-expressed oocytes, whereas TuShisa could reduce the sensitivity of TuRDL/TuShisa (mass ratio of 1: 4) channel to GABA. The homology structural models of TuRDL and TuShisa were built by the SWISS-MODEL server, their interaction was predicted using Z-DOCK and three predicted hydrogen bonds and interface residues were analysed by PyMOL. Meanwhile, the key interface residues of TuShisa affected the stability of complex were calculated by Discovery Studio 2019. In conclusion, the TuShisa, as the first reported invertebrate Shisa, was explored and functionally examined as the GABARs auxiliary subunit. Our findings provide a basis for research of invertebrate Shisa.
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Affiliation(s)
- Enling Zhan
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Jie Jiang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Ying Wang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Kexin Zhang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Tao Tang
- Institute of Plant Protection, Hunan Academy of Agricultural Sciences, Changsha 410125, PR China.
| | - Yiqu Chen
- College of Plant Science, Tibet Agricultural and Animal Husbandry University, Nyingchi 860000, PR China.
| | - Zhongqiang Jia
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Qiuxia Wang
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
| | - Chunqing Zhao
- Key Laboratory of Integrated Pest Management on Crops in East China, Ministry of Agriculture, College of Plant Protection, Nanjing Agricultural University, Nanjing 210095, PR China.
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Huang Y, Wang Q, Peng Y, Du W, Wang Q, Qi J, Hao Z, Wang Y. Spatiotemporal expression patterns of genes coding for plasmalemmal chloride transporters and channels in neurological diseases. Mol Brain 2023; 16:30. [PMID: 36934242 PMCID: PMC10024392 DOI: 10.1186/s13041-023-01018-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Accepted: 03/07/2023] [Indexed: 03/19/2023] Open
Abstract
Neuronal voltage changes which are dependent on chloride transporters and channels are involved in forming neural functions during early development and maintaining their stability until adulthood. The intracellular chloride concentration maintains a steady state, which is delicately regulated by various genes coding for chloride transporters and channels (GClTC) on the plasmalemma; however, the synergistic effect of these genes in central nervous system disorders remains unclear. In this study, we first defined 10 gene clusters with similar temporal expression patterns, and identified 41 GClTC related to brain developmental process. Then, we found 4 clusters containing 22 GClTC were enriched for the neuronal functions. The GClTC from different clusters presented distinct cell type preferences and anatomical heterogeneity. We also observed strong correlations between clustered genes and diseases, most of which were nervous system disorders. Finally, we found that one of the most well-known GClTC, SLC12A2, had a more profound effect on glial cell-related diseases than on neuron-related diseases, which was in accordance with our observation that SLC12A2 was mainly expressed in oligodendrocytes during brain development. Our findings provide a more comprehensive understanding of the temporal and spatial expression characteristics of GClTC, which can help us understand the complex roles of GClTC in the development of the healthy human brain and the etiology of brain disorders.
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Affiliation(s)
- Yanruo Huang
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Qihang Wang
- State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Center for Excellence in Molecular Cell Science, Chinese Academy of Sciences, Shanghai, 200031, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yunsong Peng
- Division of Life Sciences and Medicine, School of Biomedical Engineering (Suzhou), University of Science and Technology of China, Hefei, 230026, China
- Medical Imaging Department, Suzhou Institute of Biomedical Engineering and Technology, Chinese Academy of Sciences, Suzhou, 215163, China
| | - Wenjie Du
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Qi Wang
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Jiangtao Qi
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China
| | - Zijian Hao
- Institute of Science and Technology for Brain-Inspired Intelligence, Fudan University, Shanghai, 200433, China.
- MOE Frontiers Center for Brain Science, Fudan University, Shanghai, 200433, China.
| | - Yingwei Wang
- Department of Anesthesiology, Huashan Hospital, Fudan University, Shanghai, 200040, China.
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Stauber T, Wartosch L, Vishnolia S, Schulz A, Kornak U. CLCN7, a gene shared by autosomal recessive and autosomal dominant osteopetrosis. Bone 2023; 168:116639. [PMID: 36513280 DOI: 10.1016/j.bone.2022.116639] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/27/2022] [Accepted: 11/30/2022] [Indexed: 12/14/2022]
Abstract
After the discovery of abundant v-ATPase complexes in the osteoclast ruffled membrane it was obvious that in parallel a negative counter-ion needs to be transported across this membrane to allow for efficient transport of protons into the resorption lacuna. While different candidate proteins were discussed the osteopetrosis phenotype of Clcn7 knockout mice suggested that the chloride/proton-exchanger ClC-7 might be responsible for transporting the negative charge. In the following, individuals with autosomal recessive osteopetrosis (ARO) were found to carry biallelic CLCN7 pathogenic variants. Shortly thereafter, heterozygous pathogenic variants were identified as the exclusive cause of autosomal dominant osteopetrosis type 2 (ADO2). Since in most cell types other than osteoclasts ClC-7 resides in late endosomes and lysosomes, it took some time until the electrophysiological properties of ClC-7 were elucidated. Whereas most missense variants lead to reduced chloride currents, several variants with accelerated kinetics have been identified. Evidence for folding problems is also known for several missense variants. Paradoxically, a heterozygous activating variant in ClC-7 was described to cause lysosomal alteration, pigmentation defects, and intellectual disability without osteopetrosis. The counter-intuitive 2 Cl-/H+ exchange function of ClC-7 was shown to be physiologically important for intravesicular ion homeostasis. The lysosomal function of ClC-7 is also the reason why individuals with CLCN7-ARO can develop a storage disorder and neurodegeneration, a feature that is variable and difficult to predict. Furthermore, the low penetrance of heterozygous pathogenic CLCN7 variants and the clinical variability of ADO2 are incompletely understood. We aim to give an overview not only of the current knowledge about ClC-7 and its related pathologies, but also of the scientists and clinicians that paved the way for these discoveries.
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Affiliation(s)
- Tobias Stauber
- Institute for Molecular Medicine, MSH Medical School Hamburg, Hamburg, Germany
| | - Lena Wartosch
- Department of Meiosis, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Svenja Vishnolia
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany
| | - Ansgar Schulz
- Department of Pediatrics and Adolescent Medicine, University Medical Center Ulm, Ulm, Germany
| | - Uwe Kornak
- Institute of Human Genetics, University Medical Center Göttingen, Göttingen, Germany.
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Yuan L, Tang Y, Yin L, Lin X, Luo Z, Wang S, Li J, Liang P, Jiang B. The role of Transmembrane Protein 16A (TMEM16A) in pulmonary hypertension. Cardiovasc Pathol 2023; 65:107525. [PMID: 36781068 DOI: 10.1016/j.carpath.2023.107525] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 02/04/2023] [Accepted: 02/06/2023] [Indexed: 02/13/2023] Open
Abstract
Transmembrane protein 16A (TMEM16A), a member of the TMEM16 family, is the molecular basis of Ca2+-activated chloride channels (CaCCs) and is involved in a variety of physiological and pathological processes. Previous studies have focused more on respiratory-related diseases and tumors. However, recent studies have identified an important role for TMEM16A in cardiovascular diseases, especially in pulmonary hypertension. TMEM16A is expressed in both pulmonary artery smooth muscle cells and pulmonary artery endothelial cells and is involved in the development of pulmonary hypertension. This paper presents the structure and function of TMEM16A, the pathogenesis of pulmonary hypertension, and highlights the role and mechanism of TMEM16A in pulmonary hypertension, summarizing the controversies in this field and taking into account hypertension and portal hypertension, which have similar pathogenesis. It is hoped that the unique role of TMEM16A in pulmonary hypertension will be illustrated and provide ideas for research in this area.
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Affiliation(s)
- Ludong Yuan
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Yuting Tang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Leijing Yin
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Xiaofang Lin
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Zhengyang Luo
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Shuxin Wang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Jing Li
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China
| | - Pengfei Liang
- Department of Burns and Plastic Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Bimei Jiang
- Department of Pathophysiology, Sepsis Translational Medicine Key Laboratory of Hunan Province, Xiangya School of Medicine, Central South University, Changsha, Hunan, China; National Medicine Functional Experimental Teaching Center, Central South University, Changsha, Hunan China.
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8
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Chen B, Xie C, Shi T, Yue S, Li W, Huang G, Zhang Y, Liu W. Activation of Swell1 in microglia suppresses neuroinflammation and reduces brain damage in ischemic stroke. Neurobiol Dis 2023; 176:105936. [PMID: 36511337 DOI: 10.1016/j.nbd.2022.105936] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 10/17/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
Cl- movement and Cl--sensitive signal pathways contributes to the survival and switch of inflammatory phenotype of microglia and are believed to play a key role in the inflammatory brain injury after ischemic stroke. Here, we demonstrated an important role of Cl- transmembrane transporter Swell1, in the survival and M2-like polarization of microglia in ischemic stroke. Knockdown or overexpression of Swell1 in cultured microglia inhibited or increased hypotonic-activated Cl- currents, respectively, and these changes were completely blocked by the volume-regulated anion channels (VRACs) inhibitor DCPIB. Swell1 conditional knock-in mice promoted microglia survival in ischemic brain region and resulted in significant reductions in neural cell death, infarction volume and neurological deficits following transient middle cerebral artery occlusion (tMCAO). Using gene manipulating technique and pharmacological inhibitors, we further revealed that Swell1 opening led to SGK1 (a Cl--sensitive kinase)-mediated activation of FOXO3a/CREB as well as WNK1 (another Cl--sensitive kinase)-mediated SPAK/OSR1-CCCs activation, which promoted microglia survival and M2-like polarization, thereby attenuating neuroinflammation and ischemic brain injury. Taken together, our results demonstrated that Swell1 is an essential component of microglia VRACs and its activation protects against ischemic brain injury through promoting microglia survival and M2-like polarization.
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Affiliation(s)
- Baoyi Chen
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China
| | - Cong Xie
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China; Department of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Graduate School of Guangzhou Medical University, Shenzhen 518035, China
| | - Tengrui Shi
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China
| | - Shiqin Yue
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China; School of Pharmaceutical Sciences, Health Science Center, Shenzhen University, Shenzhen 518035, China
| | - Weiping Li
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China
| | - Guodong Huang
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China
| | - Yuan Zhang
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China.
| | - Wenlan Liu
- Department of Neurosurgery, Shenzhen Key Laboratory of Neurosurgery, The First Affiliated Hospital of Shenzhen University, Shenzhen Second People's Hospital, Shenzhen 518035, China.
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9
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Vivekanandam V, Jayaseelan D, Hanna MG. Muscle channelopathies. Handb Clin Neurol 2023; 195:521-532. [PMID: 37562884 DOI: 10.1016/b978-0-323-98818-6.00006-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/12/2023]
Abstract
Muscle channelopathies encompass a wide range of mainly episodic conditions that are characterized by muscle stiffness and weakness. The myotonic conditions, characterized predominantly by stiffness, include myotonia congenita, paramyotonia congenita, and sodium channel myotonia. The periodic paralysis conditions include hypokalemic periodic paralysis, hyperkalemic periodic paralysis, and Andersen-Tawil syndrome. Clinical history is key, and diagnosis is confirmed by next-generation genetic sequencing of a panel of known genes but can also be supplemented by neurophysiology studies and MRI. As genetic testing expands, so have the spectrum of phenotypes seen including pediatric presentations and congenital myopathies. Management of these conditions requires a multidisciplinary approach with extra support needed when patients require anesthetics or when pregnant. Patients with Andersen-Tawil syndrome will also need cardiac input. Diagnosis is important as symptomatic treatment is available for all of these conditions but need to be tailored to the gene and variant of the patient.
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Affiliation(s)
- Vinojini Vivekanandam
- Centre for Neuromuscular Disorders, Queen Square UCL Institute of Neurology, London, United Kingdom
| | | | - Michael G Hanna
- Centre for Neuromuscular Disorders, Queen Square UCL Institute of Neurology, London, United Kingdom.
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10
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Borgo C, D'Amore C, Capurro V, Tomati V, Sondo E, Cresta F, Castellani C, Pedemonte N, Salvi M. Targeting the E1 ubiquitin-activating enzyme (UBA1) improves elexacaftor/tezacaftor/ivacaftor efficacy towards F508del and rare misfolded CFTR mutants. Cell Mol Life Sci 2022; 79:192. [PMID: 35292885 PMCID: PMC8924136 DOI: 10.1007/s00018-022-04215-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 02/08/2023]
Abstract
The advent of Trikafta (Kaftrio in Europe) (a triple-combination therapy based on two correctors—elexacaftor/tezacaftor—and the potentiator ivacaftor) has represented a revolution for the treatment of patients with cystic fibrosis (CF) carrying the most common misfolding mutation, F508del-CFTR. This therapy has proved to be of great efficacy in people homozygous for F508del-CFTR and is also useful in individuals with a single F508del allele. Nevertheless, the efficacy of this therapy needs to be improved, especially in light of the extent of its use in patients with rare class II CFTR mutations. Using CFBE41o- cells expressing F508del-CFTR, we provide mechanistic evidence that targeting the E1 ubiquitin-activating enzyme (UBA1) by TAK-243, a small molecule in clinical trials for other diseases, boosts the rescue of F508del-CFTR induced by CFTR correctors. Moreover, TAK-243 significantly increases the F508del-CFTR short-circuit current induced by elexacaftor/tezacaftor/ivacaftor in differentiated human primary airway epithelial cells, a gold standard for the pre-clinical evaluation of patients’ responsiveness to pharmacological treatments. This new combinatory approach also leads to an improvement in CFTR conductance on cells expressing other rare CF-causing mutations, including N1303K, for which Trikafta is not approved. These findings show that Trikafta therapy can be improved by the addition of a drug targeting the misfolding detection machinery at the beginning of the ubiquitination cascade and may pave the way for an extension of Trikafta to low/non-responding rare misfolded CFTR mutants.
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Affiliation(s)
- Christian Borgo
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy.
| | - Claudio D'Amore
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy
| | - Valeria Capurro
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genova, Italy
| | - Valeria Tomati
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genova, Italy
| | - Elvira Sondo
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genova, Italy
| | - Federico Cresta
- Centro Fibrosi Cistica, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Carlo Castellani
- Centro Fibrosi Cistica, IRCCS Istituto Giannina Gaslini, Genova, Italy
| | - Nicoletta Pedemonte
- UOC Genetica Medica, IRCCS Istituto Giannina Gaslini, Via Gerolamo Gaslini 5, 16147, Genova, Italy.
| | - Mauro Salvi
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi 58/B, 35131, Padova, Italy.
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McComic SE, Rault LC, Anderson TD, Swale DR. Toxicological analysis of stilbenes against the fall armyworm, Spodoptera frugiperda. Pestic Biochem Physiol 2021; 179:104965. [PMID: 34802515 DOI: 10.1016/j.pestbp.2021.104965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 08/17/2021] [Accepted: 09/14/2021] [Indexed: 06/13/2023]
Abstract
The fall armyworm (FAW), Spodoptera frugiperda, is a global pest of multiple economically important row crops and the development of resistance to commercially available insecticidal classes has inhibited FAW control. Thus, there is a need to identify chemical scaffolds that can provide inspiration for the development of novel insecticides for FAW management. This study aimed to assess the sensitivity of central neurons and susceptibility of FAW to chloride channel modulators to establish a platform for repurposing existing insecticides or designing new chemicals capable of controlling FAW. Potency of select chloride channel modulators were initially studied against FAW central neuron firing rate and rank order of potency was determined to be fipronil > lindane > Z-stilbene > DIDS > GABA > E-stilbene. Toxicity bioassays identified fipronil and lindane as the two most toxic modulators studied with topical LD50's of 41 and 75 ng/mg of caterpillar, respectively. Interestingly, Z-stilbene was toxic at 300 ng/mg of caterpillar, but no toxicity was observed with DIDS or E-stilbene. The significant shift in potency between stilbene isomers indicates structure-activity relationships between stilbene chemistry and the binding site in FAW may exist. The data presented in this study defines the potency of select chloride channel modulators to FAW neural activity and survivorship to establish a platform for development of novel chemical agents to control FAW populations. Although stilbenes may hold promise for insecticide development, the low toxicity of the scaffolds tested in this study dampen enthusiasm for their development into FAW specific insecticides.
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Affiliation(s)
- Sarah E McComic
- Louisiana State University AgCenter, Department of Entomology, Baton Rouge, LA 70803, United States of America
| | - Leslie C Rault
- University of Nebraska, Department of Entomology, 103 Entomology Hall, Lincoln, NE 68583, United States of America
| | - Troy D Anderson
- University of Nebraska, Department of Entomology, 103 Entomology Hall, Lincoln, NE 68583, United States of America
| | - Daniel R Swale
- Louisiana State University AgCenter, Department of Entomology, Baton Rouge, LA 70803, United States of America.
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12
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Ye X, Liu X, Wei W, Yu H, Jin X, Yu J, Li C, Xu B, Guo X, Mao J. Volume-activated chloride channels contribute to lipopolysaccharide plus nigericin-induced pyroptosis in bone marrow-derived macrophages. Biochem Pharmacol 2021; 193:114791. [PMID: 34582774 DOI: 10.1016/j.bcp.2021.114791] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/17/2021] [Accepted: 09/24/2021] [Indexed: 01/15/2023]
Abstract
The representative morphological features of pyroptosis are excessive cell swelling and subsequent membrane rupture. However, the mechanism underlying the cell's inherent inability to regulate volume during the progression of pyroptosis is poorly understood. In the current study, we found that both volume-activated chloride currents (Icl, vol) and the regulatory volume decrease (RVD) were markedly decreased in bone marrow-derived macrophages (BMDMs) undergoing pyroptosis induced by lipopolysaccharides (LPS) and nigericin. The inhibition of ICl, vol and RVD by the chloride channel blockers, tamoxifen or DCPIB, led to the emergence of pyroptosis-like phenotypes such as activated-caspase-1, pyroptotic-body-like bubbles, and a fried-egg-like appearance. Moreover, the expression of the volume-activated chloride channel (VRAC) constituent protein Leucine-Rich Repeat-Containing 8A (LRRC8A) was significantly down-regulated in pyroptotic BMDMs treated with LPS and nigericin. The silencing of LRRC8A expression by small interfering RNA (si)-LRRC8A transfection not only reduced ICl, vol and RVD, but also caused BMDMs to show pyroptosis-like manifestations such as activated-caspase-1, membrane bubbles, and have a fried-egg-like appearance. These results reveal a new mechanism for the loss of volume regulation in the process of pyroptotic cell swelling and strongly suggest that a functional deficiency of VRAC/LRRC8A plays a key role in this disorder.
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Affiliation(s)
- Xiaomin Ye
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Xiaoyong Liu
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Wenjun Wei
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Huiping Yu
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Xiaobao Jin
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Jinwei Yu
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Chunmei Li
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Bin Xu
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China
| | - Xinmin Guo
- Department of Ultrasound, Guangzhou Red Cross Hospital, Medical College, Jinan University, Guangzhou, Guangdong 510220, PR China.
| | - Jianwen Mao
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Life Sciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, PR China.
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13
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Kasahara Y, Narukawa M, Ishimaru Y, Kanda S, Umatani C, Takayama Y, Tominaga M, Oka Y, Kondo K, Kondo T, Takeuchi A, Misaka T, Abe K, Asakura T. TMC4 is a novel chloride channel involved in high-concentration salt taste sensation. J Physiol Sci 2021; 71:23. [PMID: 34429071 PMCID: PMC10717410 DOI: 10.1186/s12576-021-00807-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 07/16/2021] [Indexed: 12/27/2022]
Abstract
"Salty taste" sensation is evoked when sodium and chloride ions are present together in the oral cavity. The presence of an epithelial cation channel that receives Na+ has previously been reported. However, no molecular entity involving Cl- receptors has been elucidated. We report the strong expression of transmembrane channel-like 4 (TMC4) in the circumvallate and foliate papillae projected to the glossopharyngeal nerve, mediating a high-concentration of NaCl. Electrophysiological analysis using HEK293T cells revealed that TMC4 was a voltage-dependent Cl- channel and the consequent currents were completely inhibited by NPPB, an anion channel blocker. TMC4 allowed permeation of organic anions including gluconate, but their current amplitudes at positive potentials were less than that of Cl-. Tmc4-deficient mice showed significantly weaker glossopharyngeal nerve response to high-concentration of NaCl than the wild-type littermates. These results indicated that TMC4 is a novel chloride channel that responds to high-concentration of NaCl.
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Affiliation(s)
- Yoichi Kasahara
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Masataka Narukawa
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Department of Food and Nutrition, Kyoto Women's University, 35 Kitahiyoshicho Imakumano Higashiyama, Kyoto, 605-8501, Japan
| | - Yoshiro Ishimaru
- Department of Agricultural Chemistry, Meiji University, 1-1-1 Higashimita, Tama-ku, Kawasaki, Kanagawa, 214-8571, Japan
| | - Shinji Kanda
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Chie Umatani
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Yasunori Takayama
- Division of Cell Signaling, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1 Aza-Higashiyama, Myodaijicho, Okazaki, Aichi, 444-8787, Japan
| | - Makoto Tominaga
- Division of Cell Signaling, National Institute for Physiological Sciences, National Institutes of Natural Sciences, 5-1 Aza-Higashiyama, Myodaijicho, Okazaki, Aichi, 444-8787, Japan
- Thermal Biology Research Group, Exploratory Research Center On Life and Living Systems (ExCELLS), National Institutes of Natural Sciences, 5-1 Aza-Higashiyama, Myodaijicho, Okazaki, Aichi, 444-8787, Japan
| | - Yoshitaka Oka
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan
| | - Kaori Kondo
- Laboratory for Developmental Genetics, RIKEN-IMS, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Takashi Kondo
- Laboratory for Developmental Genetics, RIKEN-IMS, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Ayako Takeuchi
- Department of Integrative and Systems Physiology, Faculty of Medical Sciences, and Life Science Innovation Center, University of Fukui, Fukui, 910-1193, Japan
| | - Takumi Misaka
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
| | - Keiko Abe
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan
- Kanagawa Institute of Industrial Science and Technology (KISTEC), LiSE 4F C-4, 3-25-13 Tonomachi, Kawasaki-ku, Kawasaki, Kanagawa, 210-0821, Japan
| | - Tomiko Asakura
- Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
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14
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Banderali U, Leanza L, Eskandari N, Gentile S. Potassium and Chloride Ion Channels in Cancer: A Novel Paradigm for Cancer Therapeutics. Rev Physiol Biochem Pharmacol 2021. [PMID: 34291318 DOI: 10.1007/112_2021_62] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Cancer is a collection of diseases caused by specific changes at the genomic level that support cell proliferation indefinitely. Traditionally, ion channels are known to control a variety of cellular processes including electrical signal generation and transmission, secretion, and contraction by controlling ionic gradients. However, recent studies had brought to light important facts on ion channels in cancer biology.In this review we discuss the mechanism linking potassium or chloride ion channel activity to biochemical pathways controlling proliferation in cancer cells and the potential advantages of targeting ion channels as an anticancer therapeutic option.
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15
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Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel shows only weak selectivity between different small monovalent anions, however, little is known about its ability to discriminate between monovalent and divalent anions. The present study uses patch clamp recording to investigate the interaction between the small divalent anions S2O32- and SO42- and wild-type and pore-mutant forms of human CFTR. Binding of these anions to wild-type CFTR appears weak; at 10 mM, intracellular S2O32- and SO42- blocked <20 and <5% of macroscopic Cl- current respectively, while these same concentrations had no discernible blocking effect when present in the extracellular solution. However, introduction of additional positive charge into the inner vestibule of the pore (in I344K and S1141K mutant channels) drastically strengthened block by intracellular (but not extracellular) S2O32- and SO42-. Block of these mutant channels was highly voltage-dependent; at very negative membrane potentials, apparent binding affinities were ~100 µM for S2O32- and <1 mM for SO42-. Permeability of S2O32- and SO42- was too small to be quantified in wild-type CFTR, but was <1% of Cl- permeability. Mutants that strengthened divalent binding (I344K, S1141K), as well as the selectivity-altering mutant F337A, also showed immeasurably low S2O32- and SO42- permeabilities. Overall CFTR selects well for monovalent over divalent anions, both in terms of binding and permeability. The number or density of fixed positive charges in the pore appears well optimized to disfavour binding of divalent anions, which may be an important facet of the monovalent Cl- permeation mechanism.
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Affiliation(s)
- Paul Linsdell
- Department of Physiology & Biophysics, Dalhousie University, Halifax, NS, Canada.
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16
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Linsdell P, Irving CL, Cowley EA, El Hiani Y. Two positively charged amino acid side-chains in the inner vestibule of the CFTR channel pore play analogous roles in controlling anion binding and anion conductance. Cell Mol Life Sci 2021; 78:5213-5223. [PMID: 34023918 DOI: 10.1007/s00018-021-03859-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 05/06/2021] [Accepted: 05/15/2021] [Indexed: 12/18/2022]
Abstract
Positively charged amino acid side-chains play important roles in anion binding and permeation through the CFTR chloride channel. One pore-lining lysine residue in particular (K95) has been shown to be indispensable for anion binding, conductance, and selectivity. Here, we use functional investigation of CFTR to show that a nearby arginine (R134) plays a functionally analogous role. Removal of this positive charge (in the R134Q mutant) drastically reduces single-channel conductance, weakens binding of both permeant and blocking anions, and abolishes the normal anion conductance selectivity pattern. Each of these functional effects was reversed by a second-site mutation (S1141K) that introduces an ectopic positive charge to a nearby pore-lining residue. Substituted cysteine accessibility experiments confirm that R134-but not nearby residues in the same transmembrane helix-is accessible within the pore lumen. These results suggest that K95 and R134, which are very close together within the inner vestibule of the pore, play analogous, important roles, and that both are required for the normal anion binding and anion conductance properties of the pore. Nevertheless, that fact that both positive charges can be "transplanted" to other sites in the inner vestibule with little effect on channel permeation properties indicates that it is the overall number of charges-rather than their exact locations-that controls pore function.
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Affiliation(s)
- Paul Linsdell
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada.
| | - Christina L Irving
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Elizabeth A Cowley
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Yassine El Hiani
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
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17
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Linsdell P. On the relationship between anion binding and chloride conductance in the CFTR anion channel. Biochim Biophys Acta Biomembr 2021; 1863:183558. [PMID: 33444622 DOI: 10.1016/j.bbamem.2021.183558] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/21/2020] [Accepted: 12/29/2020] [Indexed: 12/26/2022]
Abstract
Mutations at many sites within the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel pore region result in changes in chloride conductance. Although chloride binding in the pore - as well as interactions between concurrently bound chloride ions - are thought to be important facets of the chloride permeation mechanism, little is known about the relationship between anion binding and chloride conductance. The present work presents a comprehensive investigation of a number of anion binding properties in different pore mutants with differential effects on chloride conductance. When multiple pore mutants are compared, conductance appears best correlated with the ability of anions to bind to the pore when it is already occupied by chloride ions. In contrast, conductance was not correlated with biophysical measures of anion:anion interactions inside the pore. Although these findings suggest anion binding is required for high conductance, mutations that strengthened anion binding had very little effect on conductance, especially at high chloride concentrations, suggesting that the wild-type CFTR pore is already close to saturated with chloride ions. These results are used to support a revised model of chloride permeation in CFTR in which the overall chloride occupancy of multiple loosely-defined chloride binding sites results in high chloride conductance through the pore.
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Affiliation(s)
- Paul Linsdell
- Department of Physiology & Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada.
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18
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Tsujimura M, Noji T, Saito K, Kojima K, Sudo Y, Ishikita H. Mechanism of absorption wavelength shifts in anion channelrhodopsin-1 mutants. Biochim Biophys Acta Bioenerg 2020; 1862:148349. [PMID: 33248117 DOI: 10.1016/j.bbabio.2020.148349] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/07/2020] [Revised: 11/05/2020] [Accepted: 11/21/2020] [Indexed: 12/11/2022]
Abstract
Using a quantum mechanical/molecular mechanical approach, we show the mechanisms of how the protein environment of Guillardia theta anion channelrhodopsin-1 (GtACR1) can shift the absorption wavelength. The calculated absorption wavelengths for GtACR1 mutants, M105A, C133A, and C237A are in agreement with experimentally measured wavelengths. Among 192 mutant structures investigated, mutations at Thr101, Cys133, Pro208, and Cys237 are likely to increase the absorption wavelength. In particular, T101A GtACR1 was expressed in HEK293T cells. The measured absorption wavelength is 10 nm higher than that of wild type, consistent with the calculated wavelength. (i) Removal of a polar residue from the Schiff base moiety, (ii) addition of a polar or acidic residue to the β-ionone ring moiety, and (iii) addition of a bulky residue to increase the planarity of the β-ionone and Schiff base moieties are the basis of increasing the absorption wavelength.
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Affiliation(s)
- Masaki Tsujimura
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan
| | - Tomoyasu Noji
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Keisuke Saito
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan
| | - Keiichi Kojima
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Yuki Sudo
- Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama 700-8530, Japan
| | - Hiroshi Ishikita
- Department of Applied Chemistry, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan; Research Center for Advanced Science and Technology, The University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8904, Japan.
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19
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Chen L, König B, Stauber T. LRRC8 channel activation and reduction in cytosolic chloride concentration during early differentiation of C2C12 myoblasts. Biochem Biophys Res Commun 2020; 532:482-488. [PMID: 32892951 DOI: 10.1016/j.bbrc.2020.08.080] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 08/23/2020] [Indexed: 01/09/2023]
Abstract
Leucine-rich repeat containing family 8 (LRRC8) proteins form the volume-regulated anion channel (VRAC). Recently, they were shown to be required for normal differentiation and fusion of C2C12 myoblasts, by promoting membrane hyperpolarization and intracellular Ca2+ signals. However, the mechanism by which they are involved remained obscure. Here, using a FRET-based sensor for VRAC activity, we show temporary activation of VRAC within the first 2 h of myogenic differentiation. During this period, we also observed a significant decrease in the intracellular Cl- concentration that was abolished by the VRAC inhibitor carbenoxolone. However, lowering the intracellular Cl- concentration by extracellular Cl- depletion did not promote differentiation as judged by the percentage of myogenin-positive nuclei or total myogenin levels in C2C12 cells. Instead, it inhibited myosin expression and myotube formation. Together, these data suggest that VRAC is activated and mediates Cl- efflux early on during myogenic differentiation, and a moderate intracellular Cl- concentration is necessary for myoblast fusion.
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Affiliation(s)
- Lingye Chen
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Benjamin König
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany
| | - Tobias Stauber
- Institute of Chemistry and Biochemistry, Freie Universität Berlin, Thielallee 63, 14195, Berlin, Germany; Department of Human Medicine and Institute for Molecular Medicine, MSH Medical School Hamburg, Am Kaiserkai 1, 20457, Hamburg, Germany.
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20
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Shi J, Shi S, Yuan G, Jia Q, Shi S, Zhu X, Zhou Y, Chen T, Hu Y. Bibliometric analysis of chloride channel research (2004-2019). Channels (Austin) 2020; 14:393-402. [PMID: 33103563 PMCID: PMC7588193 DOI: 10.1080/19336950.2020.1835334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Affiliation(s)
- Jingjing Shi
- China Academy of Chinese Medical Sciences, Guanganmen Hospital , Beijing, China
| | - Shuqing Shi
- Graduate School, Beijing University of Chinese Medicine , Beijing, China
| | - Guozhen Yuan
- China Academy of Chinese Medical Sciences, Guanganmen Hospital , Beijing, China
| | - QiuLei Jia
- Graduate School, Beijing University of Chinese Medicine , Beijing, China
| | - Shuai Shi
- China Academy of Chinese Medical Sciences, Guanganmen Hospital , Beijing, China
| | - Xueping Zhu
- China Academy of Chinese Medical Sciences, Guanganmen Hospital , Beijing, China
| | - Yan Zhou
- Graduate School, Beijing University of Chinese Medicine , Beijing, China
| | - Ting Chen
- Graduate School, Beijing University of Chinese Medicine , Beijing, China
| | - Yuanhui Hu
- China Academy of Chinese Medical Sciences, Guanganmen Hospital , Beijing, China
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21
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Rodrigues DDJ, Damasceno AD, Araújo CETD, Torelli SR, Fonseca LGH, Delfiol DJZ, Oliveira-Filho JPD, Araújo-Júnior JP, Borges AS. Hereditary myotonia in American Bulldog associated with a novel frameshift mutation in the CLCN1 gene. Neuromuscul Disord 2020; 30:991-998. [PMID: 33246886 DOI: 10.1016/j.nmd.2020.10.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 10/06/2020] [Accepted: 10/16/2020] [Indexed: 11/19/2022]
Abstract
Hereditary myotonia (HM) is a genetic disorder that occurs due to mutations in the chloride channel and results in delayed relaxation of the skeletal muscles. HM has been described in 12 dog breeds, and in five of them, molecular studies of this disorder were performed and mutations in the CLCN1 gene were described. In this study, an affected American Bulldog with HM clinically characterized by muscle hypertrophy, myotonic discharges, and nondystrophic myotonia with a "warm-up" phenomenon was evaluated, and the candidate canine CLCN1 gene was sequenced. The molecular analysis revealed a frameshift mutation NM_001003124.2:c.436_437insCTCT that resulted in a frameshift and a premature stop codon NP_001003124.1:pTyr146SerfsTer49 . Two aberrant alternative CLCN1 transcripts were observed in an affected dog, the expected transcript with the 4 bp insertion, NM_001003124.2:r.436_437insctct, and an unexpected transcript containing parts of intron 6 in addition to the insertion in exon 4, NM_001003124.2:[r.436_437insctct;r.774_775ins79]. In conclusion, the frameshift mutation in the CLCN1 gene is associated with autosomal recessive HM in American Bulldog and this study constitutes the first description of the disease in this breed.
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Affiliation(s)
- Daiane de Jesus Rodrigues
- Department of Veterinary Clinical Science, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. Rua Prof. Dr. Walter Maurício Corrêa, s/n, Botucatu, SP, Brazil
| | - Adilson Donizeti Damasceno
- School of Veterinary and Animal Science, Universidade Federal de Goiás, Goiânia, Goiás, Brazil. Rodovia Goiânia, km 8 s/n Campus - Samambaia, Goiânia, GO 74001-970, Brazil
| | - César Erineudo Tavares de Araújo
- University Center UNILEAO, Juazeiro do Norte, Ceará, Brazil. Av. Maria Letícia Leite Pereira s/n, Lagoa Seca - Cidade Universitária, Juazeiro do Norte, CE 63040-405, Brazil
| | - Sandra Regina Torelli
- CALE - Animal Surgery and Specialized Diagnostic Laboratory, Jundiaí, São Paulo, Brazil, Rua Itália, 106 - Jardim Bonfiglioli, Jundiaí, SP 13207-280, Brazil
| | - Luine Gabriela Hilário Fonseca
- Self-employed Veterinary, Catalão, Goiás, Brazil, Rua Paraná, 330 - Nossa senhora de Fátima, Catalão, GO 75709-240, Brazil
| | - Diego José Zanzarini Delfiol
- School of Veterinary Medicine, Universidade Federal de Uberlândia, Uberlândia, Minas Gerais, Brazil, Av. Mato Grosso, 3289 - Bloco 2S - Umuarama, Uberlândia, MG 38405-314, Brazil
| | - José Paes de Oliveira-Filho
- Department of Veterinary Clinical Science, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. Rua Prof. Dr. Walter Maurício Corrêa, s/n, Botucatu, SP 18618-681, Brazil
| | - João Pessoa Araújo-Júnior
- Institute of Biotechnology, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. Alameda das Tecomarias, s/n - Chácara Capão Bonito, Botucatu, SP 18607-440, Brazil
| | - Alexandre Secorun Borges
- Department of Veterinary Clinical Science, School of Veterinary Medicine and Animal Science, Universidade Estadual Paulista, Botucatu, São Paulo, Brazil. Rua Prof. Dr. Walter Maurício Corrêa, s/n, Botucatu, SP 18618-681, Brazil.
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Shin DH, Kim M, Kim Y, Jun I, Jung J, Nam JH, Cheng MH, Lee MG. Bicarbonate permeation through anion channels: its role in health and disease. Pflugers Arch 2020; 472:1003-1018. [PMID: 32621085 DOI: 10.1007/s00424-020-02425-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Revised: 06/19/2020] [Accepted: 06/26/2020] [Indexed: 12/31/2022]
Abstract
Many anion channels, frequently referred as Cl- channels, are permeable to different anions in addition to Cl-. As the second-most abundant anion in the human body, HCO3- permeation via anion channels has many important physiological roles. In addition to its classical role as an intracellular pH regulator, HCO3- also controls the activity and stability of dissolved proteins in bodily fluids such as saliva, pancreatic juice, intestinal fluid, and airway surface liquid. Moreover, HCO3- permeation through these channels affects membrane potentials that are the driving forces for transmembrane transport of solutes and water in epithelia and affect neuronal excitability in nervous tissue. Consequently, aberrant HCO3- transport via anion channels causes a number of human diseases in respiratory, gastrointestinal, genitourinary, and neuronal systems. Notably, recent studies have shown that the HCO3- permeabilities of several anion channels are not fixed and can be altered by cellular stimuli, findings which may have both physiological and pathophysiological significance. In this review, we summarize recent progress in understanding the molecular mechanisms and the physiological roles of HCO3- permeation through anion channels. We hope that the present discussions can stimulate further research into this very important topic, which will provide the basis for human disorders associated with aberrant HCO3- transport.
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Affiliation(s)
- Dong Hoon Shin
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Minjae Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Yonjung Kim
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Ikhyun Jun
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- The Institute of Vision Research, Department of Ophthalmology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Jinsei Jung
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, 03722, South Korea
| | - Joo Hyun Nam
- Department of Physiology, Dongguk University College of Medicine, 123 Dongdae-ro, Kyungju, 780-714, Republic of Korea
| | - Mary Hongying Cheng
- Department of Computational & Systems Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Min Goo Lee
- Department of Pharmacology, Brain Korea 21 PLUS Project for Medical Sciences, Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea.
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23
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Sánchez-Solano A, Corral N, Segura-Covarrubias G, Guzmán-Hernández ML, Arechiga-Figueroa I, Cruz-Rangel S, Pérez-Cornejo P, Arreola J. Regulation of the Ca 2+-activated chloride channel Anoctamin-1 (TMEM16A) by Ca 2+-induced interaction with FKBP12 and calcineurin. Cell Calcium 2020; 89:102211. [PMID: 32422433 DOI: 10.1016/j.ceca.2020.102211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Revised: 03/30/2020] [Accepted: 04/23/2020] [Indexed: 12/26/2022]
Abstract
Chloride fluxes through the calcium-gated chloride channel Anoctamin-1 (TMEM16A) control blood pressure, secretion of saliva, mucin, insulin, and melatonin, gastrointestinal motility, sperm capacitation and motility, and pain sensation. Calcium activates a myriad of regulatory proteins but how these proteins affect TMEM16A activity is unresolved. Here we show by co-immunoprecipitation that increasing intracellular calcium with ionomycin or by activating sphingosine-1-phosphate receptors, induces coupling of calcium/calmodulin-dependent phosphatase calcineurin and prolyl isomerase FK506-binding protein 12 (FKBP12) to TMEM16A in HEK-293 cells. Application of drugs that target either calcineurin (cyclosporine A) or FKBP12 (tacrolimus known as FK506 and sirolimus known as rapamycin) caused a decrease in TMEM16A activity. In addition, FK506 and BAPTA-AM prevented co-immunoprecipitation between FKBP12 and TMEM16A. FK506 rendered the channel insensitive to cyclosporine A without altering its apparent calcium sensitivity whereas zero intracellular calcium blocked the effect of FK506. Rapamycin decreased TMEM16A activity in cells pre-treated with cyclosporine A or FK506. These results suggest the formation of a TMEM16A-FKBP12-calcineurin complex that regulates channel function. We conclude that upon a cytosolic calcium increase the TMEM16A-FKPB12-calcineurin trimers are assembled. Such hetero-oligomerization enhances TMEM16A channel activity but is not mandatory for activation by calcium.
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Affiliation(s)
- Alfredo Sánchez-Solano
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP 78290, Mexico
| | - Nancy Corral
- Department of Physiology and Biophysics, Universidad Autónoma de San Luis Potosí School of Medicine, Ave. V. Carranza 2405, San Luis Potosí, SLP 78290, Mexico
| | - Guadalupe Segura-Covarrubias
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP 78290, Mexico
| | - María Luisa Guzmán-Hernández
- Cátedra CONACYT, School of Medicine, Universidad Autónoma de San Luis Potosí, Ave. V. Carranza 2405, San Luis Potosí, SLP 78290, Mexico
| | - Ivan Arechiga-Figueroa
- Cátedra CONACYT, School of Medicine, Universidad Autónoma de San Luis Potosí, Ave. V. Carranza 2405, San Luis Potosí, SLP 78290, Mexico
| | - Silvia Cruz-Rangel
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP 78290, Mexico
| | - Patricia Pérez-Cornejo
- Department of Physiology and Biophysics, Universidad Autónoma de San Luis Potosí School of Medicine, Ave. V. Carranza 2405, San Luis Potosí, SLP 78290, Mexico
| | - Jorge Arreola
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, San Luis Potosí, SLP 78290, Mexico.
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24
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Abstract
PURPOSE OF REVIEW Megalin is well known for its role in the reabsorption of proteins from the ultrafiltrate. Recent studies suggest that megalin also reabsorbs renin and angiotensinogen. Indeed, without megalin urinary renin and angiotensinogen levels massively increase, and even prorenin becomes detectable in urine. RECENT FINDINGS Intriguingly, megalin might also contribute to renal angiotensin production, as evidenced from studies in megalin knockout mice. This review discusses these topics critically, concluding that urinary renin-angiotensin system components reflect diminished reabsorption rather than release from renal tissue sites and that alterations in renal renin levels or megalin-dependent signaling need to be ruled out before concluding that angiotensin production at renal tissue sites is truly megalin dependent. Future studies should evaluate megalin-mediated renin/angiotensinogen transcytosis (allowing interstitial angiotensin generation), and determine whether megalin prefers prorenin over renin, thus explaining why urine normally contains no prorenin.
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Affiliation(s)
- Yuan Sun
- Department of Internal Medicine, Division of Pharmacology and Vascular Medicine, Erasmus MC, room EE1418b, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
- Translational Medicine Collaborative Innovation Center, The Second Clinical Medical College (Shenzhen People's Hospital) of Jinan University, Shenzhen, China
| | - Xifeng Lu
- Department of Physiology, Shenzhen University Health Science Center, Shenzhen University, Shenzhen, China
| | - A H Jan Danser
- Department of Internal Medicine, Division of Pharmacology and Vascular Medicine, Erasmus MC, room EE1418b, Wytemaweg 80, 3015 CN, Rotterdam, The Netherlands.
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25
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Kawai S, Fujii T, Shimizu T, Sukegawa K, Hashimoto I, Okumura T, Nagata T, Sakai H, Fujii T. Pathophysiological properties of CLIC3 chloride channel in human gastric cancer cells. J Physiol Sci 2020; 70:15. [PMID: 32066374 PMCID: PMC7026216 DOI: 10.1186/s12576-020-00740-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 02/04/2020] [Indexed: 11/24/2022]
Abstract
Pathophysiological functions of chloride intracellular channel protein 3 (CLIC3) in human gastric cancer have been unclear. In the tissue microarray analysis using 107 gastric cancer specimens, CLIC3 expression was negatively correlated with pathological tumor depth, and the patients with lower expression of CLIC3 exhibited poorer prognosis. CLIC3 was expressed in the plasma membrane of cancer cells in the tissue. CLIC3 expression was also found in a human gastric cancer cell line (MKN7). In whole-cell patch-clamp recordings of the cells expressing CLIC3, NPPB-sensitive outwardly rectifying Cl− currents were observed. Cell proliferation was significantly accelerated by knockdown of CLIC3 in MKN7 cells. On the other hand, the proliferation was attenuated by exogenous CLIC3 expression in human gastric cancer cells (KATOIII and NUGC-4) in which endogenous CLIC3 expression is negligible. Our results suggest that CLIC3 functions as a Cl− channel in the plasma membrane of gastric cancer cells and that decreased expression of CLIC3 results in unfavorable prognosis of gastric cancer patients.
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Affiliation(s)
- Shunsuke Kawai
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Takuto Fujii
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Takahiro Shimizu
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan
| | - Kenta Sukegawa
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Isaya Hashimoto
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Tomoyuki Okumura
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Takuya Nagata
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
| | - Hideki Sakai
- Department of Pharmaceutical Physiology, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, 2630 Sugitani, Toyama, 930-0194, Japan.
| | - Tsutomu Fujii
- Department of Surgery and Sciences, Graduate School of Medicine and Pharmaceutical Sciences, University of Toyama, Toyama, 930-0194, Japan
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26
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Linsdell P, Negoda A, Cowley EA, El Hiani Y. Electrostatic Tuning of Anion Attraction from the Cytoplasm to the Pore of the CFTR Chloride Channel. Cell Biochem Biophys 2020; 78:15-22. [PMID: 31893350 DOI: 10.1007/s12013-019-00899-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 12/17/2019] [Indexed: 10/25/2022]
Abstract
Anions enter from the cytoplasm into the channel pore of the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel not via a central pathway but via a single lateral portal or fenestration. High Cl- conductance is dependent on electrostatic attraction of cytoplasmic Cl- ions by four positively charged amino acid side-chains located within this portal. Here we use a mutagenic approach to investigate the functional effects of transplanting or supplementing these positive charges at nearby portal-lining sites. Using patch clamp recording, we find that the functionally important positive charges at K190 and R303 can be transplanted to four nearby sites (N186, L197, W356, and A367) with little loss of Cl- conductance. Introduction of additional positive charge at these sites had almost no effect on Cl- conductance, but did increase the sensitivity to channel block by intracellular suramin and Pt(NO2)42- anions. We suggest that it is the number of positive charges within the portal, rather than their exact location, that is the most important factor influencing Cl- conductance. The portal appears well optimized in terms of charge distribution to maximize Cl- conductance.
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27
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Zhong J, Qin Z, Yu H, Liu X, Li C, Shi J, Mao J, Xu B. NPPB prevents postoperative peritoneal adhesion formation by blocking volume-activated Cl - current. Naunyn Schmiedebergs Arch Pharmacol 2019; 393:501-510. [PMID: 31659404 DOI: 10.1007/s00210-019-01740-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/20/2019] [Indexed: 12/11/2022]
Abstract
5-Nitro-2-(3-phenylpropylamino)-benzoic acid (NPPB) is a non-specific chloride channel blocker. Peritoneal adhesion is an inevitable complication of abdominal surgery and remains an important clinical problem, leading to chronic pain, intestinal obstruction, and female infertility. The aim of this study is to observe the effects of NPPB on peritoneal adhesions and uncover the underlying mechanism. The formation of postoperative peritoneal adhesions was induced by mechanical injury to the peritoneum of rats. MTT assay and wound-healing assay were used to evaluate proliferation and migration of primary cultured adhesion fibroblasts (AFB) respectively. Whole-cell chloride currents were measured using a fully automated patch-clamp workstation. Cell volume changes were monitored by light microscopy and video imaging. Our results demonstrated that NPPB could significantly prevent the formation of peritoneal adhesion in rats and inhibit the proliferation of AFB in a concentration-dependent manner. NPPB also reduced the migration of AFB cells with an IC50 of 53.09 μM. A 47% hypotonic solution successfully activated the ICl,vol in AFB cells. The current could be blocked by extracellular treatment with NPPB. Moreover, 100 μM NPPB almost completely eliminated the capacity of regulatory volume decrease (RVD) in these cells. These data indicate that NPPB could prevent the formation of postoperative peritoneal adhesions. The possible mechanism may be through the inhibition of the proliferation and migration of AFB cells by modulating ICl,vol and cell volume. These results suggest a potential clinical use of NPPB for preventing the formation of peritoneal adhesions.
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Affiliation(s)
- Jie Zhong
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Zhuan Qin
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Huiping Yu
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Xueqiang Liu
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Chunmei Li
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Jingwen Shi
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China
| | - Jianwen Mao
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China.
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China.
| | - Bin Xu
- School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China.
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances, Guangdong Pharmaceutical University, Guangzhou, 510006, Guangdong, People's Republic of China.
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28
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Xu X, Xu J, Zhao C, Hou X, Li M, Wang L, Chen L, Chen Y, Zhu L, Yang H. Antitumor effects of disulfiram/copper complex in the poorly-differentiated nasopharyngeal carcinoma cells via activating ClC-3 chloride channel. Biomed Pharmacother 2019; 120:109529. [PMID: 31606620 DOI: 10.1016/j.biopha.2019.109529] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 09/30/2019] [Accepted: 10/01/2019] [Indexed: 12/17/2022] Open
Abstract
The enhancement of the anticancer activity by disulfiram (DSF) chelated with copper (DSF/Cu2+) has been investigated recently, while the underlying molecular mechanisms still need to be fully elucidated. Chloride channel-3 (ClC-3) is over-expressed in a variety of cancers and involves multiple tumor biological events. However, whether the over-expression of ClC-3 in tumor cells affects the sensitivity of anti-tumor drugs remains unclear. Here, we showed that the involvement of ClC-3 chloride channel in the selective cytotoxicity of DSF/Cu2+ in the poorly-differentiated nasopharyngeal carcinoma. The EC50 of DSF alone and DSF/Cu2+ in activating the Cl- channel were 95.36 μM and 0.31 μM in the CNE-2Z cells, respectively. DSF/Cu2+ exhibited a positive correlation between the induction of the Cl- currents and the inhibition of cell proliferation. DSF/Cu2+ increased the ClC-3 protein expression and induced the cell apoptosis. Cl- channel blockers, NPPB and DIDS, and ClC-3 siRNA partially inhibited the cell apoptosis, and depleted the Cl- currents induced by DSF/Cu2+ in CNE-2Z cells. However, these effects could not be observed in the normal nasopharyngeal epithelium NP69-SV40 T cells. In vivo, the transplanted human nasopharyngeal carcinoma tumors size in the DSF/Cu2+ group decreased about 73.2% of those in the solvent control group. The chloride blockers partially inhibited the antitumor action of DSF/Cu2+. These data demonstrated that the selective cytotoxicity of DSF/Cu2+ may relate to its selective activation of ClC-3 Cl- channel pathways in CNE-2Z cells. ClC-3 Cl- channel can be viewed as a new and promising target for the treatment of nasopharyngeal carcinoma.
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Affiliation(s)
- Xiao Xu
- Department of Physiology, School of Medicine, Henan University, Kaifeng, 475000, China; Department of Physiology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Jingkui Xu
- Department of Physiology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Chongyu Zhao
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Xiuying Hou
- Department of Physiology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Mengjia Li
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Liwei Wang
- Department of Physiology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Lixin Chen
- Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, 510632, China
| | - Yehui Chen
- Department of Urology, Guangzhou First People's Hospital, Guangzhou, 510180, China
| | - Linyan Zhu
- Department of Physiology, School of Medicine, Jinan University, Guangzhou, 510632, China; Department of Pharmacology, School of Medicine, Jinan University, Guangzhou, 510632, China.
| | - Haifeng Yang
- Department of Pathology, The Second Affiliated Hospital of Guangzhou University of Chinese Medicine (Guangdong Provincial Hospital of Chinese Medicine), Guangzhou, 510120, China.
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29
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Farkas B, Tordai H, Padányi R, Tordai A, Gera J, Paragi G, Hegedűs T. Discovering the chloride pathway in the CFTR channel. Cell Mol Life Sci 2019; 77:765-778. [PMID: 31327045 PMCID: PMC7039865 DOI: 10.1007/s00018-019-03211-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 06/22/2019] [Accepted: 06/26/2019] [Indexed: 12/15/2022]
Abstract
Cystic fibrosis (CF), a lethal monogenic disease, is caused by pathogenic variants of the CFTR chloride channel. The majority of CF mutations affect protein folding and stability leading overall to diminished apical anion conductance of epithelial cells. The recently published cryo-EM structures of full-length human and zebrafish CFTR provide a good model to gain insight into structure–function relationships of CFTR variants. Although, some of the structures were determined in the phosphorylated and ATP-bound active state, none of the static structures showed an open pathway for chloride permeation. Therefore, we performed molecular dynamics simulations to generate a conformational ensemble of the protein and used channel detecting algorithms to identify conformations with an opened channel. Our simulations indicate a main intracellular entry at TM4/6, a secondary pore at TM10/12, and a bottleneck region involving numerous amino acids from TM1, TM6, and TM12 in accordance with experiments. Since chloride ions entered the pathway in our equilibrium simulations, but did not traverse the bottleneck region, we performed metadynamics simulations, which revealed two possible exits. One of the chloride ions exits includes hydrophobic lipid tails that may explain the lipid-dependency of CFTR function. In summary, our in silico study provides a detailed description of a potential chloride channel pathway based on a recent cryo-EM structure and may help to understand the gating of the CFTR chloride channel, thus contributing to novel strategies to rescue dysfunctional mutants.
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Affiliation(s)
- Bianka Farkas
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.,Faculty of Information Technology, Pázmány Péter Catholic University, Budapest, Hungary
| | - Hedvig Tordai
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary
| | - Rita Padányi
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary.,MTA-SE Molecular Biophysics Research Group, Hungarian Academy of Sciences, Budapest, Hungary
| | - Attila Tordai
- Department of Pathophysiology, Semmelweis University, Budapest, Hungary
| | - János Gera
- Department of Medical Chemistry, University of Szeged, Szeged, Hungary
| | - Gábor Paragi
- MTA-SZTE Biomimetic System Research Group, Hungarian Academy of Sciences, Szeged, Hungary.,Institute of Physics, University of Pécs, Pecs, Hungary
| | - Tamás Hegedűs
- Department of Biophysics and Radiation Biology, Semmelweis University, Budapest, Hungary. .,MTA-SE Molecular Biophysics Research Group, Hungarian Academy of Sciences, Budapest, Hungary.
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30
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Pérez-Rius C, Castellanos A, Gaitán-Peñas H, Navarro A, Artuch R, Barrallo-Gimeno A, Estévez R. Role of zebrafish ClC-K/barttin channels in apical kidney chloride reabsorption. J Physiol 2019; 597:3969-3983. [PMID: 31177533 DOI: 10.1113/jp278069] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Accepted: 05/29/2019] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS We have characterized the zebrafish clc-k and barttin proteins, demonstrating that they form a protein complex mediating chloride flux in a similar manner to their mammalian counterparts. As in mammals, in zebrafish, clc-k and barttin are basically expressed in the kidney. Contrary to what is found in mammals, in zebrafish both proteins show an apical localization in the kidney. We have generated the first knockout in zebrafish of a CLC protein. Lack of clc-k in zebrafish resulted in embryonic lethality, possibly caused by a reduction in total chloride content. As a consequence, there is an up-regulation of other chloride channels and other regulatory mechanisms such as renin or the uro-guanylin receptor in the kidney. barttin is mislocalized in vivo when clc-k is not present, indicating that there is a mutual dependence of the protein expression and localization between barttin and clc-k proteins. ABSTRACT ClC-K/barttin channels are very important for salt transport in the kidney. This function can be clearly seen since mutations in CLCNKB or BSND cause Bartter's syndrome types III and IV, respectively. Working with the freshwater teleost zebrafish, we characterized the genes homologous to the mammalian chloride channel ClC-K and its obligate subunit barttin and we obtained and studied clc-k knockout zebrafish. The zebrafish clc-k/barttin proteins are very similar to their mammalian counterparts, and both proteins are necessary to mediate chloride currents. Localization studies indicated that both proteins are exclusively expressed in the apical membranes of zebrafish kidney tubules. Knockout of clc-k resulted in embryonic lethality. These animals showed barttin mislocalization and a reduction in whole-body chloride concentration, as well as up-regulation of the expression of other chloride channels and renin, and an increase in the kidney expression of the uroguanylin receptor. Our results indicate that apical kidney chloride reabsorption through clc-k/barttin channels is crucial for chloride homeostasis in zebrafish as it is in humans. The zebrafish model could be used as a new in vivo system to study ClC-K function.
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Affiliation(s)
- Carla Pérez-Rius
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Aida Castellanos
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Héctor Gaitán-Peñas
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Almudena Navarro
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain
| | - Rafael Artuch
- Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain.,Clinical Biochemistry Department, Institut de Recerca Sant Joan de Déu, Hospital Sant Joan de Déu, Esplugues de Llobregat, Spain
| | - Alejandro Barrallo-Gimeno
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
| | - Raúl Estévez
- Unitat de Fisiologia, Departament de Ciències Fisiològiques, Genes, Disease and Therapy Program, IDIBELL-Institute of Neurosciences, Universitat de Barcelona, L'Hospitalet de Llobregat, Barcelona, Spain.,Centro de Investigación en Red de Enfermedades Raras (CIBERER), ISCIII, Madrid, Spain
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31
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Haworth AS, Brackenbury WJ. Emerging roles for multifunctional ion channel auxiliary subunits in cancer. Cell Calcium 2019; 80:125-140. [PMID: 31071485 PMCID: PMC6553682 DOI: 10.1016/j.ceca.2019.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Revised: 04/16/2019] [Accepted: 04/16/2019] [Indexed: 02/07/2023]
Abstract
Several superfamilies of plasma membrane channels which regulate transmembrane ion flux have also been shown to regulate a multitude of cellular processes, including proliferation and migration. Ion channels are typically multimeric complexes consisting of conducting subunits and auxiliary, non-conducting subunits. Auxiliary subunits modulate the function of conducting subunits and have putative non-conducting roles, further expanding the repertoire of cellular processes governed by ion channel complexes to processes such as transcellular adhesion and gene transcription. Given this expansive influence of ion channels on cellular behaviour it is perhaps no surprise that aberrant ion channel expression is a common occurrence in cancer. This review will focus on the conducting and non-conducting roles of the auxiliary subunits of various Ca2+, K+, Na+ and Cl- channels and the burgeoning evidence linking such auxiliary subunits to cancer. Several subunits are upregulated (e.g. Cavβ, Cavγ) and downregulated (e.g. Kvβ) in cancer, while other subunits have been functionally implicated as oncogenes (e.g. Navβ1, Cavα2δ1) and tumour suppressor genes (e.g. CLCA2, KCNE2, BKγ1) based on in vivo studies. The strengthening link between ion channel auxiliary subunits and cancer has exposed these subunits as potential biomarkers and therapeutic targets. However further mechanistic understanding is required into how these subunits contribute to tumour progression before their therapeutic potential can be fully realised.
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Affiliation(s)
- Alexander S Haworth
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK
| | - William J Brackenbury
- Department of Biology, University of York, Heslington, York, YO10 5DD, UK; York Biomedical Research Institute, University of York, Heslington, York, YO10 5DD, UK.
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Park M, Jung HG, Kweon HJ, Kim YE, Park JY, Hwang EM. The E3 ubiquitin ligase, NEDD4L (NEDD4-2) regulates bestrophin-1 (BEST1) by ubiquitin-dependent proteolysis. Biochem Biophys Res Commun 2019; 514:344-350. [PMID: 31036321 DOI: 10.1016/j.bbrc.2019.04.078] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 04/11/2019] [Indexed: 11/26/2022]
Abstract
The bestrophin family comprises well-known Ca2+-activated chloride channels (CaCC) that are expressed in a variety tissues including the brain, eye, gastrointestinal tract, and muscle tissues. Among the family members, bestrophin-1 (BEST1) is known to exist mainly in retinal pigment epithelium cells, but we recently reported that BEST1 mediates Ca2+-activated Cl- currents in hippocampal astrocytes. Despite its critical roles in physiological processes, including tonic γ-aminobutyric acid release and glutamate transport, the mechanisms that regulate BEST1 are poorly understood. In this study, we identified NEDD4L (NEDD4-2), an E3 ubiquitin ligase, as a binding partner of BEST1. A series of deletion constructs revealed that the WW3-4 domains of NEDD4L were important for interaction with BEST1. We observed that BEST1 underwent ubiquitin-dependent proteolysis and found that the conserved lysine370 residue in the C-terminus of BEST1 was important for its ubiquitination. Finally, we demonstrated that NEDD4L inhibited whole cell currents mediated by BEST1 but not by the BEST1(K370R) mutant. Collectively, our data demonstrated that NEDD4L played a critical role in regulating the surface expression of BEST1 by promoting its internalization and degradation.
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Affiliation(s)
- Myeongki Park
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea
| | - Hyun-Gug Jung
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, 02841, Republic of Korea
| | - Hae-Jin Kweon
- Neuroscience Discovery, Janssen Pharmaceutical Companies of Johnson & Johnson, 3210 Merryfield Row, San Diego, CA, 92121, USA
| | - Yeong-Eun Kim
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea
| | - Jae-Yong Park
- School of Biosystem and Biomedical Science, College of Health Science, Korea University, Seoul, 02841, Republic of Korea.
| | - Eun Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, 02792, Republic of Korea; Neuroscience Program, University of Science and Technology (UST), Daejeon, 305-350, Republic of Korea.
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Stowasser M, Wolley M, Wu A, Gordon RD, Schewe J, Stölting G, Scholl UI. Pathogenesis of Familial Hyperaldosteronism Type II: New Concepts Involving Anion Channels. Curr Hypertens Rep 2019; 21:31. [PMID: 30949771 DOI: 10.1007/s11906-019-0934-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
PURPOSE OF REVIEW The application of advanced genetic techniques has recently begun to unravel the genetic basis for familial primary aldosteronism type 2 (FH-II). RECENT FINDINGS Whole-exome sequencing in a large family with FH-II revealed a shared rare damaging heterozygous variant in CLCN2 (chr.3: g.184075850C>T, p.Arg172Gln) in three severely affected members. The gene encodes a chloride channel, ClC-2. A cohort of 80 unrelated individuals diagnosed with early-onset primary aldosteronism was also examined for CLCN2 mutations finding three further occurrences of p.Arg172Gln mutations and four single cases of other potentially damaging heterozygous mutations for an overall prevalence of 9.9%. A concurrent report also found a different CLCN2 mutation (p.Gly24Asp) in a single severely affected patient from a cohort of 12 with early-onset PA for a prevalence of 8.3%. Cases of primary aldosteronism associated with CLCN2 mutations appear to be bilateral and respond well to medical treatment. In the adrenal, ClC-2 has been demonstrated to localize predominantly to the zona glomerulosa (ZG), and functional analysis suggests that mutations in ClC-2 predispose ZG cells to depolarization, thus leading to calcium influx via activation of voltage-gated calcium channels and increased aldosterone production. Germline CLCN2 mutations appear to account for a substantial proportion of early-onset primary aldosteronism cases, and genetic testing for mutations in this gene should be considered in appropriate cases.
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Negoda A, Hogan MS, Cowley EA, Linsdell P. Contribution of the eighth transmembrane segment to the function of the CFTR chloride channel pore. Cell Mol Life Sci 2019; 76:2411-2423. [PMID: 30758641 DOI: 10.1007/s00018-019-03043-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/18/2019] [Accepted: 02/06/2019] [Indexed: 12/20/2022]
Abstract
Our molecular understanding of the cystic fibrosis transmembrane conductance regulator (CFTR)-the chloride channel that is mutated in cystic fibrosis-has been greatly enhanced by a number of recent atomic-level structures of the protein in different conformations. One surprising aspect of these structures was the finding that the eighth of CFTR's 12 membrane-spanning segments (TM8) appeared close to the channel pore. Although functional evidence supports a role for other TMs in forming the pore, such a role for TM8 has not previously been reported. Here, we use patch-clamp recording to investigate the functional role of TM8. Using substituted cysteine accessibility mutagenesis, we find that three amino acid side-chains in TM8 (Y913, Y914, and Y917) are exposed to the extracellular, but not the intracellular, solution. Cysteine cross-linking experiments suggest that Y914 and Y917 are in close proximity to L102 (TM1) and F337 (TM6), respectively, suggesting that TM8 contributes to the narrow selectivity filter region of the pore. Different amino acid substitutions suggest that Y914, and to a lesser extent Y917, play important roles in controlling anion flux through the open channel. Furthermore, substitutions that reduce side-chain volume at Y917 severely affect channel gating, resulting in a channel with an extremely unstable open state. Our results suggest that pore-lining TM8 is among the most important TMs controlling the permeation phenotype of the CFTR channel, and also that movement of TM8 may be critically involved in channel gating.
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Affiliation(s)
- Alexander Negoda
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Mairin S Hogan
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Elizabeth A Cowley
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada
| | - Paul Linsdell
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada.
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Negoda A, Cowley EA, El Hiani Y, Linsdell P. Conformational change of the extracellular parts of the CFTR protein during channel gating. Cell Mol Life Sci 2018; 75:3027-38. [PMID: 29441426 DOI: 10.1007/s00018-018-2777-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Revised: 01/24/2018] [Accepted: 02/08/2018] [Indexed: 12/21/2022]
Abstract
Cystic fibrosis can be treated by potentiators, drugs that interact directly with the cystic fibrosis transmembrane conductance regulator (CFTR) Cl- channel to increase its open probability. These substances likely target key conformational changes occurring during channel opening and closing, however, the molecular bases of these conformational changes, and their susceptibility to manipulation are poorly understood. We have used patch clamp recording to identify changes in the three-dimensional organization of the extracellularly accessible parts of the CFTR protein during channel opening and closing. State-dependent formation of both disulfide bonds and Cd2+ bridges occurred for pairs of cysteine side-chains introduced into the extreme extracellular ends of transmembrane helices (TMs) 1, 6, and 12. Between each of these three TMs, we found that both disulfide bonds and metal bridges formed preferentially or exclusively in the closed state and that these inter-TM cross-links stabilized the closed state. These results indicate that the extracellular ends of these TMs are close together when the channel is closed and that they separate from each other when the channel opens. These findings identify for the first time key conformational changes in the extracellular parts of the CFTR protein that can potentially be manipulated to control channel activity.
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Li C, Huang D, Tang J, Chen M, Lu Q, Li H, Zhang M, Xu B, Mao J. ClC-3 chloride channel is involved in isoprenaline-induced cardiac hypertrophy. Gene 2017; 642:335-342. [PMID: 29158167 DOI: 10.1016/j.gene.2017.11.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2017] [Revised: 10/26/2017] [Accepted: 11/15/2017] [Indexed: 01/01/2023]
Abstract
Isoprenaline, an activator of β-adrenergic receptor, has been found to induce cardiac hypertrophy in vivo and in vitro, but the exact mechanism is still unclear. ClC-3 is a member of the chloride channel family and is highly expressed in mammalian myocardium. In the present study, the role of ClC-3 in isopronaline-induced cardiac hypertrophy was investigated. We found that ClC-3 expression was reduced in isoprenaline-induced hypertrophic H9c2 cells, primary rat neonatal cardiomyocytes and myocardium of C57/BL/6 mice, and this reduction was prevented by the pretreatment of propranolol. Adeno-associated virus 9 (AAV9)-mediated ClC-3 expression in myocardium decreased heart mass index, thinned interventricular septum and left ventricular wall and lowered the mRNA expression of natriuretic peptide type A (ANF) and β-myosin heavy chain (β-MHC). Our results showed that ClC-3 played an important role in β-adrenergic cardiac hypertrophy which could be associated with ANF and β-MHC, and all these findings suggested that ClC-3 may be a novel therapeutic target for the prevention or treatment of myocardiac hypertrophy.
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Affiliation(s)
- Chunmei Li
- Department of Biochemistry and Molecular Biology, Guangdong Pharmaceutical University, Guangzhou 510006, China; Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Basic Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Dan Huang
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Basic Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China; Hunan Traditional Chinese Medical College, Zhuzhou, 412012, China
| | - Jing Tang
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Basic Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Mengqing Chen
- Department of Biochemistry and Molecular Biology, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - Qun Lu
- Department of Biochemistry and Molecular Biology, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | - He Li
- Department of Biochemistry and Molecular Biology, Guangdong Pharmaceutical University, Guangzhou 510006, China
| | | | - Bin Xu
- Guangdong Province Key Laboratory for Biotechnology Drug Candidates and School of Biosciences and Biopharmaceutics, Guangdong Pharmaceutical University, Guangzhou 510006, China.
| | - Jianwen Mao
- Guangdong Provincial Key Laboratory of Pharmaceutical Bioactive Substances and School of Basic Medicine, Guangdong Pharmaceutical University, Guangzhou 510006, China.
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Pongkorpsakol P, Yimnual C, Chatsudthipong V, Rukachaisirikul V, Muanprasat C. Cellular mechanisms underlying the inhibitory effect of flufenamic acid on chloride secretion in human intestinal epithelial cells. J Pharmacol Sci 2017; 134:93-100. [PMID: 28651800 DOI: 10.1016/j.jphs.2017.05.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/09/2017] [Accepted: 05/19/2017] [Indexed: 01/10/2023] Open
Abstract
Intestinal Cl- secretion is involved in the pathogenesis of secretory diarrheas including cholera. We recently demonstrated that flufenamic acid (FFA) suppressed Vibrio cholerae El Tor variant-induced intestinal fluid secretion via mechanisms involving AMPK activation and NF-κB-suppression. The present study aimed to investigate the effect of FFA on transepithelial Cl- secretion in human intestinal epithelial (T84) cells. FFA inhibited cAMP-dependent Cl- secretion in T84 cell monolayers with IC50 of ∼8 μM. Other fenamate drugs including tolfenamic acid, meclofenamic acid and mefenamic acid exhibited the same effect albeit with lower potency. FFA also inhibited activities of CFTR, a cAMP-activated apical Cl- channel, and KCNQ1/KCNE3, a cAMP-activated basolateral K+ channel. Mechanisms of CFTR inhibition by FFA did not involve activation of its negative regulators. Interestingly, FFA inhibited Ca2+-dependent Cl- secretion with IC50 of ∼10 μM. FFA inhibited activities of Ca2+-activated Cl- channels and KCa3.1, a Ca2+-activated basolateral K+ channels, but had no effect on activities of Na+-K+-Cl- cotransporters and Na+-K+ ATPases. These results indicate that FFA inhibits both cAMP and Ca2+-dependent Cl- secretion by suppressing activities of both apical Cl- channels and basolateral K+ channels. FFA and other fenamate drugs may be useful in the treatment of secretory diarrheas.
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Affiliation(s)
- Pawin Pongkorpsakol
- Translational Medicine Graduate Program, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand
| | - Chantapol Yimnual
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand
| | - Varanuj Chatsudthipong
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand
| | - Vatcharin Rukachaisirikul
- Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Prince of Songkla University, Hat Yai, Songkhla 90112, Thailand
| | - Chatchai Muanprasat
- Department of Physiology, Faculty of Science, Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand; Excellent Center for Drug Discovery (ECDD), Mahidol University, Rama VI Road, Rajathevi, Bangkok 10400, Thailand.
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Peckys DB, Stoerger C, Latta L, Wissenbach U, Flockerzi V, de Jonge N. The stoichiometry of the TMEM16A ion channel determined in intact plasma membranes of COS-7 cells using liquid-phase electron microscopy. J Struct Biol 2017; 199:102-113. [PMID: 28559167 DOI: 10.1016/j.jsb.2017.05.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 05/24/2017] [Accepted: 05/25/2017] [Indexed: 11/29/2022]
Abstract
TMEM16A is a membrane protein forming a calcium-activated chloride channel. A homodimeric stoichiometry of the TMEM16 family of proteins has been reported but an important question is whether the protein resides always in a dimeric configuration in the plasma membrane or whether monomers of the protein are also present in its native state within in the intact plasma membrane. We have determined the stoichiometry of the human (h)TMEM16A within whole COS-7 cells in liquid. For the purpose of detecting TMEM16A subunits, single proteins were tagged by the streptavidin-binding peptide within extracellular loops accessible by streptavidin coated quantum dot (QD) nanoparticles. The labeled proteins were then imaged using correlative light microscopy and environmental scanning electron microscopy (ESEM) using scanning transmission electron microscopy (STEM) detection. The locations of 19,583 individual proteins were determined of which a statistical analysis using the pair correlation function revealed the presence of a dimeric conformation of the protein. The amounts of detected label pairs and single labels were compared between experiments in which the TMEM16A SBP-tag position was varied, and experiments in which tagged and non-tagged TMEM16A proteins were present. It followed that hTMEM16A resides in the plasma membrane as dimer only and is not present as monomer. This strategy may help to elucidate the stoichiometry of other membrane protein species within the context of the intact plasma membrane in future.
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Affiliation(s)
- Diana B Peckys
- Department of Biophysics, Saarland University, 66421 Homburg, Germany
| | - Christof Stoerger
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Lorenz Latta
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Ulrich Wissenbach
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Veit Flockerzi
- Experimental and Clinical Pharmacology and Toxicology, Saarland University, 66421 Homburg, Germany
| | - Niels de Jonge
- INM - Leibniz Institute for New Materials, Saarland University, 66123 Saarbrücken, Germany; Department of Physics, Saarland University, 66123 Saarbrücken, Germany.
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Islam R, Zhang Y, Xu L, Sah P, Lynch JW. A Chemogenetic Receptor That Enhances the Magnitude and Frequency of Glycinergic Inhibitory Postsynaptic Currents without Inducing a Tonic Chloride Flux. ACS Chem Neurosci 2017; 8:460-467. [PMID: 27958714 DOI: 10.1021/acschemneuro.6b00382] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The gene transfer-mediated expression of inhibitory ion channels in nociceptive neurons holds promise for treating intractable pain. Chemogenetics, which involves expressing constructs activated by biologically inert molecules, is of particular interest as it permits tunable neuromodulation. However, current chloride-permeable chemogenetic constructs are problematic as they mediate a tonic chloride influx which over time would deplete the chloride electrochemical gradient and reduce inhibitory efficacy. Inflammatory pain sensitization can be caused by prostaglandin E2-mediated inhibition of glycinergic inhibitory postsynaptic currents in spinal nociceptive neurons. We developed a highly conducting (100 pS) inhibitory chemogenetic construct based on a human glycine receptor (α1Y279F,A288G) with high ivermectin sensitivity. When virally infected into spinal neurons, 10 nM ivermectin increased the magnitude and frequency of glycinergic postsynaptic currents without activating a tonic chloride flux. The construct should thus produce analgesia. Its human origin and the well-established biocompatibility of its ligand suggest it may be suited to human use.
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Affiliation(s)
- Robiul Islam
- Queensland Brain Institute and ‡School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Yan Zhang
- Queensland Brain Institute and ‡School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Li Xu
- Queensland Brain Institute and ‡School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Pankaj Sah
- Queensland Brain Institute and ‡School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Joseph W. Lynch
- Queensland Brain Institute and ‡School of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
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Islam R, Keramidas A, Xu L, Durisic N, Sah P, Lynch JW. Ivermectin-Activated, Cation-Permeable Glycine Receptors for the Chemogenetic Control of Neuronal Excitation. ACS Chem Neurosci 2016; 7:1647-1657. [PMID: 27611437 DOI: 10.1021/acschemneuro.6b00168] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
The ability to control neuronal activation is rapidly advancing our understanding of brain function and is widely viewed as having eventual therapeutic application. Although several highly effective optogenetic, optochemical genetic, and chemogenetic techniques have been developed for this purpose, new approaches may provide better solutions for addressing particular questions and would increase the number of neuronal populations that can be controlled independently. An early chemogenetic neuronal silencing method employed a glutamate receptor Cl- channel engineered for activation by 1-3 nM ivermectin. This construct has been validated in vivo. Here, we sought to develop cation-permeable ivermectin-gated receptors that were either maximally Ca2+-permeable so as to induce neuro-excitotoxic cell death or minimally Ca2+-permeable so as to depolarize neurons with minimal excitotoxic risk. Our constructs were based on the human α1 glycine receptor Cl- channel due to its high conductance, human origin, high ivermectin sensitivity (once mutated), and because pore mutations that render it permeable to Na+ alone or Na+ plus Ca2+ are well characterized. We developed a Ca2+-impermeable excitatory receptor by introducing the F207A/P-2'Δ/A-1'E/T13'V/A288G mutations and a Ca2+-permeable excitatory receptor by introducing the F207A/A-1'E/A288G mutations. The latter receptor efficiently induces cell death and strongly depolarizes neurons at nanomolar ivermectin concentrations.
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Affiliation(s)
- Robiul Islam
- Queensland
Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Angelo Keramidas
- Queensland
Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Li Xu
- Queensland
Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Nela Durisic
- Queensland
Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Pankaj Sah
- Queensland
Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Joseph W. Lynch
- Queensland
Brain Institute, The University of Queensland, Brisbane, QLD 4072, Australia
- School
of Biomedical Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
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Abstract
The main function of the cystic fibrosis transmembrane conductance regulator (CFTR) is as an ion channel for the movement of small anions across epithelial cell membranes. As an ion channel, CFTR must form a continuous pathway across the cell membrane-referred to as the channel pore-for the rapid electrodiffusional movement of ions. This review summarizes our current understanding of the architecture of the channel pore, as defined by electrophysiological analysis and molecular modeling studies. This includes consideration of the characteristic functional properties of the pore, definition of the overall shape of the entire extent of the pore, and discussion of how the molecular structure of distinct regions of the pore might control different facets of pore function. Comparisons are drawn with closely related proteins that are not ion channels, and also with structurally unrelated proteins with anion channel function. A simple model of pore function is also described.
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Affiliation(s)
- Paul Linsdell
- Department of Physiology and Biophysics, Dalhousie University, PO Box 15000, Halifax, NS, B3H 4R2, Canada.
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Kumagai K, Toyoda F, Staunton C, Maeda T, Okumura N, Matsuura H, Matsusue Y, Imai S, Barrett-Jolley R. Activation of a chondrocyte volume-sensitive Cl(-) conductance prior to macroscopic cartilage lesion formation in the rabbit knee anterior cruciate ligament transection osteoarthritis model. Osteoarthritis Cartilage 2016; 24:1786-1794. [PMID: 27266646 PMCID: PMC5756537 DOI: 10.1016/j.joca.2016.05.019] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 04/29/2016] [Accepted: 05/25/2016] [Indexed: 02/02/2023]
Abstract
OBJECTIVE The anterior cruciate ligament transection (ACLT) rabbit osteoarthritis (OA) model confers permanent knee instability and induces joint degeneration. The degeneration process is complex, but includes chondrocyte apoptosis and OA-like loss of cartilage integrity. Previously, we reported that activation of a volume-sensitive Cl(-) current (ICl,vol) can mediate cell shrinkage and apoptosis in rabbit articular chondrocytes. Our objective was therefore to investigate whether ICl,vol was activated in the early stages of the rabbit ACLT OA model. DESIGN Adult Rabbits underwent unilateral ACLT and contralateral arthrotomy (sham) surgery. Rabbits were euthanized at 2 or 4 weeks. Samples were analyzed histologically and with assays of cell volume, apoptosis and electrophysiological characterization of ICl,vol. RESULTS At 2 and 4 weeks post ACLT cartilage appeared histologically normal, nevertheless cell swelling and caspase 3/7 activity were both significantly increased compared to sham controls. In cell-volume experiments, exposure of chondrocytes to hypotonic solution led to a greater increase in cell size in ACLT compared to controls. Caspase-3/7 activity, an indicator of apoptosis, was elevated in both ACLT 2wk and 4wk. Whole-cell currents were recorded with patch clamp of chondrocytes in iso-osmotic and hypo-osmotic external solutions under conditions where Na(+), K(+) and Ca(2+) currents were minimized. ACLT treatment resulted in a large increase in hypotonic-activated chloride conductance. CONCLUSION Changes in chondrocyte ion channels take place prior to the onset of apparent cartilage loss in the ACLT rabbit model of OA. Further studies are needed to investigate if pharmacological inhibition of ICl,vol decreases progression of OA in animal models.
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Affiliation(s)
- K. Kumagai
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, UK,Department of Orthopedic Surgery, Shiga University of Medical Science, Japan
| | - F. Toyoda
- Department of Physiology, Shiga University of Medical Science, Japan
| | - C.A. Staunton
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, UK
| | - T. Maeda
- Department of Orthopedic Surgery, Shiga University of Medical Science, Japan
| | - N. Okumura
- Department of Orthopedic Surgery, Shiga University of Medical Science, Japan
| | - H. Matsuura
- Department of Physiology, Shiga University of Medical Science, Japan
| | - Y. Matsusue
- Department of Orthopedic Surgery, Shiga University of Medical Science, Japan
| | - S. Imai
- Department of Orthopedic Surgery, Shiga University of Medical Science, Japan
| | - R. Barrett-Jolley
- Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, UK,Address correspondence and reprint requests to: R. Barrett-Jolley, Department of Musculoskeletal Biology, Institute of Aging and Chronic Disease, University of Liverpool, UK.Department of Musculoskeletal BiologyInstitute of Aging and Chronic DiseaseUniversity of LiverpoolUK
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Wanitchakool P, Ousingsawat J, Sirianant L, MacAulay N, Schreiber R, Kunzelmann K. Cl - channels in apoptosis. Eur Biophys J 2016; 45:599-610. [PMID: 27270446 DOI: 10.1007/s00249-016-1140-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Revised: 05/06/2016] [Accepted: 05/14/2016] [Indexed: 12/28/2022]
Abstract
A remarkable feature of apoptosis is the initial massive cell shrinkage, which requires opening of ion channels to allow release of K+, Cl-, and organic osmolytes to drive osmotic water movement and cell shrinkage. This article focuses on the role of the Cl- channels LRRC8, TMEM16/anoctamin, and cystic fibrosis transmembrane conductance regulator (CFTR) in cellular apoptosis. LRRC8A-E has been identified as a volume-regulated anion channel expressed in many cell types. It was shown to be required for regulatory and apoptotic volume decrease (RVD, AVD) in cultured cell lines. Its presence also determines sensitivity towards cytostatic drugs such as cisplatin. Recent data point to a molecular and functional relationship of LRRC8A and anoctamins (ANOs). ANO6, 9, and 10 (TMEM16F, J, and K) augment apoptotic Cl- currents and AVD, but it remains unclear whether these anoctamins operate as Cl- channels or as regulators of other apoptotic Cl- channels, such as LRRC8. CFTR has been known for its proapoptotic effects for some time, and this effect may be based on glutathione release from the cell and increase in cytosolic reactive oxygen species (ROS). Although we find that CFTR is activated by cell swelling, it is possible that CFTR serves RVD/AVD through accumulation of ROS and activation of independent membrane channels such as ANO6. Thus activation of ANO6 will support cell shrinkage and induce additional apoptotic events, such as membrane phospholipid scrambling.
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Affiliation(s)
- Podchanart Wanitchakool
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Jiraporn Ousingsawat
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Lalida Sirianant
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Nanna MacAulay
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - 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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Ousingsawat J, Cabrita I, Wanitchakool P, Sirianant L, Krautwald S, Linkermann A, Schreiber R, Kunzelmann K. Ca 2+ signals, cell membrane disintegration, and activation of TMEM16F during necroptosis. Cell Mol Life Sci 2016; 74:173-181. [PMID: 27535660 DOI: 10.1007/s00018-016-2338-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 08/08/2016] [Accepted: 08/09/2016] [Indexed: 11/29/2022]
Abstract
Activated receptor-interacting protein kinase 3 (RIPK3) and mixed lineage kinase domain like (MLKL) are essential components of the necroptotic pathway. Phosphorylated MLKL (pMLKL) is thought to induce membrane leakage, leading to cell swelling and disintegration of the cell membrane. However, the molecular identity of the necroptotic membrane pore remains unclear, and the role of pMLKL for membrane permeabilization is currently disputed. We observed earlier that the phospholipid scramblase and ion channel TMEM16F/anoctamin 6 cause large membrane currents, cell swelling, and cell death when activated by a strong increase in intracellular Ca2+. We, therefore, asked whether TMEM16F is also central to necroptotic cell death and other cellular events during necroptosis. Necroptosis was induced by TNFα, smac mimetic, and Z-VAD (TSZ) in NIH3T3 fibroblasts and the four additional cell lines HT29, 16HBE, H441, and L929. Time-dependent changes in intracellular Ca2+, cell morphology, and membrane currents were recorded. TSZ induced a small and only transient oscillatory rise in intracellular Ca2+, which was paralleled by the activation of outwardly rectifying Cl- currents, which were typical for TMEM16F/ANO6. Ca2+ oscillations were due to Ca2+ release from endoplasmic reticulum, and were independent of extracellular Ca2+. The initial TSZ-induced cell swelling was followed by cell shrinkage. Using typical channel blockers and siRNA-knockdown, the Cl- currents were shown to be due to the activation of ANO6. However, the knockdown of ANO6 or inhibitors of ANO6 did not inhibit necroptotic cell death. The present data demonstrate the activation of ANO6 during necroptosis, which, however, is not essential for cell death.
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Affiliation(s)
- Jiraporn Ousingsawat
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Inês Cabrita
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Podchanart Wanitchakool
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Lalida Sirianant
- Institut für Physiologie, Universität Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Stefan Krautwald
- Division of Nephrology and Hypertension, Christian-Albrechts-University, Kiel, Germany
| | - Andreas Linkermann
- Division of Nephrology and Hypertension, Christian-Albrechts-University, Kiel, Germany
| | - 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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Kato H, Kokunai Y, Dalle C, Kubota T, Madokoro Y, Yuasa H, Uchida Y, Ikeda T, Mochizuki H, Nicole S, Fontaine B, Takahashi MP, Mitake S. A case of non-dystrophic myotonia with concomitant mutations in the SCN4A and CLCN1 genes. J Neurol Sci 2016; 369:254-258. [PMID: 27653901 DOI: 10.1016/j.jns.2016.08.030] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2015] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 11/17/2022]
Abstract
Non-dystrophic myotonias are caused by mutations of either the skeletal muscle chloride (CLCN1) or sodium channel (SCN4A) gene. They exhibit several distinct phenotypes, including myotonia congenita, paramyotonia congenita and sodium channel myotonia, and a genotype-phenotype correlation has been established. However, there are atypical cases that do not fit with the standard classification. We report a case of 27-year-old male who had non-dystrophic myotonia with periodic paralysis and two heterozygous mutations, E950K in CLCN1 and F1290L in SCN4A. His mother, who exhibited myotonia without paralytic attack, only harbored E950K, and no mutations were identified in his asymptomatic father. Therefore, the E950K mutation was presumed to be pathogenic, although it was reported as an extremely rare genetic variant. The proband experienced paralytic attacks that lasted for weeks and were less likely to be caused by CLCN1 mutation alone. Functional analysis of the F1290L mutant channel heterologously expressed in cultured cells revealed enhanced activation inducing membrane hyperexcitability. We therefore propose that the two mutations had additive effects on membrane excitability that resulted in more prominent myotonia in the proband. Our case stresses the value of performing genetic analysis of both CLCN1 and SCN4A genes for myotonic patients with an atypical phenotype.
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Affiliation(s)
- Hideki Kato
- Department of Neurology, Tosei General Hospital, Japan
| | - Yosuke Kokunai
- Department of Neurology, Osaka University Graduate School of Medicine, Japan; INSERM U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière - ICM and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, France
| | - Carine Dalle
- INSERM U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière - ICM and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, France
| | - Tomoya Kubota
- Department of Neurology, Osaka University Graduate School of Medicine, Japan; Department of Biochemistry and Molecular Biology, The University of Chicago, United States; Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Japan
| | - Yuta Madokoro
- Department of Neurology, Tosei General Hospital, Japan
| | | | - Yuto Uchida
- Department of Neurology, Tosei General Hospital, Japan
| | | | - Hideki Mochizuki
- Department of Neurology, Osaka University Graduate School of Medicine, Japan
| | - Sophie Nicole
- INSERM U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière - ICM and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, France
| | - Bertrand Fontaine
- INSERM U1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, Institut du Cerveau et de la Moelle Épinière - ICM and National Reference Center for Muscular Channelopathies, University Hospital Pitié-Salpêtrière, France
| | - Masanori P Takahashi
- Department of Neurology, Osaka University Graduate School of Medicine, Japan; Department of Functional Diagnostic Science, Osaka University Graduate School of Medicine, Japan.
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Li J, Chang Q, Li X, Li X, Qiao J, Gao T. Enhancement of an outwardly rectifying chloride channel in hippocampal pyramidal neurons after cerebral ischemia. Brain Res 2016; 1644:107-17. [PMID: 27181516 DOI: 10.1016/j.brainres.2016.05.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 05/08/2016] [Accepted: 05/09/2016] [Indexed: 10/21/2022]
Abstract
Cerebral ischemia induces delayed, selective neuronal death in the CA1 region of the hippocampus. The underlying molecular mechanisms remain unclear, but it is known that apoptosis is involved in this process. Chloride efflux has been implicated in the progression of apoptosis in various cell types. Using both the inside-out and whole-cell configurations of the patch-clamp technique, the present study characterized an outwardly rectifying chloride channel (ORCC) in acutely dissociated pyramid neurons in the hippocampus of adult rats. The channel had a nonlinear current-voltage relationship with a conductance of 42.26±1.2pS in the positive voltage range and 18.23±0.96pS in the negative voltage range, indicating an outward rectification pattern. The channel is Cl(-) selective, and the open probability is voltage-dependent. It can be blocked by the classical Cl(-) channel blockers DIDS, SITS, NPPB and glibenclamide. We examined the different changes in ORCC activity in CA1 and CA3 pyramidal neurons at 6, 24 and 48h after transient forebrain ischemia. In the vulnerable CA1 neurons, ORCC activity was persistently enhanced after ischemic insult, whereas in the invulnerable CA3 neurons, no significant changes occurred. Further analysis of channel kinetics suggested that multiple openings are a major contributor to the increase in channel activity after ischemia. Pharmacological blockade of the ORCC partly attenuated cell death in the hippocampal neurons. We propose that the enhanced activity of ORCC might contribute to selective neuronal damage in the CA1 region after cerebral ischemia, and that ORCC may be a therapeutic target against ischemia-induced cell death.
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Affiliation(s)
- Jianguo Li
- Department of Physiology, Shanxi Medical University, Taiyuan 030001, China.
| | - Quanzhong Chang
- Department of Neurobiology, Southern Medical University, Guangzhou 510515, China
| | - Xiaoming Li
- Department of Neurobiology, Southern Medical University, Guangzhou 510515, China
| | - Xiawen Li
- Department of Neurobiology, Southern Medical University, Guangzhou 510515, China
| | - Jiantian Qiao
- Department of Physiology, Shanxi Medical University, Taiyuan 030001, China
| | - Tianming Gao
- Department of Neurobiology, Southern Medical University, Guangzhou 510515, China.
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Rahmati N, Vinueza Veloz MF, Xu J, Barone S, Rodolfo Ben Hamida N, Schonewille M, Hoebeek FE, Soleimani M, De Zeeuw CI. SLC26A11 (KBAT) in Purkinje Cells Is Critical for Inhibitory Transmission and Contributes to Locomotor Coordination. eNeuro 2016; 3:ENEURO. [PMID: 27390771 DOI: 10.1523/ENEURO.0028-16.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 05/21/2016] [Accepted: 05/24/2016] [Indexed: 11/24/2022] Open
Abstract
Chloride homeostasis determines the impact of inhibitory synaptic transmission and thereby mediates the excitability of neurons. Even though cerebellar Purkinje cells (PCs) receive a pronounced inhibitory GABAergic input from stellate and basket cells, the role of chloride homeostasis in these neurons is largely unknown. Here we studied at both the cellular and systems physiological level the function of a recently discovered chloride channel, SLC26A11 or kidney brain anion transporter (KBAT), which is prominently expressed in PCs. Using perforated patch clamp recordings of PCs, we found that a lack of KBAT channel in PC-specific KBAT KO mice (L7-KBAT KOs) induces a negative shift in the reversal potential of chloride as reflected in the GABAA-receptor-evoked currents, indicating a decrease in intracellular chloride concentration. Surprisingly, both in vitro and in vivo PCs in L7-KBAT KOs showed a significantly increased action potential firing frequency of simple spikes, which correlated with impaired motor performance on the Erasmus Ladder. Our findings support an important role for SLC26A11 in moderating chloride homeostasis and neuronal activity in the cerebellum.
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Contreras-Vite JA, Cruz-Rangel S, De Jesús-Pérez JJ, Figueroa IAA, Rodríguez-Menchaca AA, Pérez-Cornejo P, Hartzell HC, Arreola J. Revealing the activation pathway for TMEM16A chloride channels from macroscopic currents and kinetic models. Pflugers Arch 2016; 468:1241-1257. [PMID: 27138167 DOI: 10.1007/s00424-016-1830-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Revised: 04/19/2016] [Accepted: 04/21/2016] [Indexed: 01/11/2023]
Abstract
TMEM16A (ANO1), the pore-forming subunit of calcium-activated chloride channels, regulates several physiological and pathophysiological processes such as smooth muscle contraction, cardiac and neuronal excitability, salivary secretion, tumour growth and cancer progression. Gating of TMEM16A is complex because it involves the interplay between increases in intracellular calcium concentration ([Ca(2+)]i), membrane depolarization, extracellular Cl(-) or permeant anions and intracellular protons. Our goal here was to understand how these variables regulate TMEM16A gating and to explain four observations. (a) TMEM16A is activated by voltage in the absence of intracellular Ca(2+). (b) The Cl(-) conductance is decreased after reducing extracellular Cl(-) concentration ([Cl(-)]o). (c) ICl is regulated by physiological concentrations of [Cl(-)]o. (d) In cells dialyzed with 0.2 μM [Ca(2+)]i, Cl(-) has a bimodal effect: at [Cl(-)]o <30 mM TMEM16A current activates with a monoexponential time course, but above 30 mM, [Cl(-)]o ICl activation displays fast and slow kinetics. To explain the contribution of Vm, Ca(2+) and Cl(-) to gating, we developed a 12-state Markov chain model. This model explains TMEM16A activation as a sequential, direct, and Vm-dependent binding of two Ca(2+) ions coupled to a Vm-dependent binding of an external Cl(-) ion, with Vm-dependent transitions between states. Our model predicts that extracellular Cl(-) does not alter the apparent Ca(2+) affinity of TMEM16A, which we corroborated experimentally. Rather, extracellular Cl(-) acts by stabilizing the open configuration induced by Ca(2+) and by contributing to the Vm dependence of activation.
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Affiliation(s)
- Juan A Contreras-Vite
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, Zona Universitaria, San Luis Potosí, SLP 78290, México
| | - Silvia Cruz-Rangel
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, Zona Universitaria, San Luis Potosí, SLP 78290, México
| | - José J De Jesús-Pérez
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, Zona Universitaria, San Luis Potosí, SLP 78290, México
| | - Iván A Aréchiga Figueroa
- CONACYT - Universidad Autónoma de San Luis Potosí School of Medicine, Ave. V. Carranza 2405, San Luis Potosí, SLP 78290, México
| | - Aldo A Rodríguez-Menchaca
- Department of Physiology, Universidad Autónoma de San Luis Potosí School of Medicine, Ave. V. Carranza 2405, San Luis Potosí, SLP 78290, México
| | - Patricia Pérez-Cornejo
- Department of Physiology, Universidad Autónoma de San Luis Potosí School of Medicine, Ave. V. Carranza 2405, San Luis Potosí, SLP 78290, México
| | - H Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Jorge Arreola
- Physics Institute, Universidad Autónoma de San Luis Potosí, Ave. Dr. Manuel Nava #6, Zona Universitaria, San Luis Potosí, SLP 78290, México.
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Pesce E, Gorrieri G, Sirci F, Napolitano F, Carrella D, Caci E, Tomati V, Zegarra-Moran O, di Bernardo D, Galietta LJV. Evaluation of a systems biology approach to identify pharmacological correctors of the mutant CFTR chloride channel. J Cyst Fibros 2016; 15:425-35. [PMID: 26971626 DOI: 10.1016/j.jcf.2016.02.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 01/21/2016] [Accepted: 02/22/2016] [Indexed: 11/28/2022]
Abstract
BACKGROUND Mistrafficking of CFTR protein caused by F508del, the most frequent mutation in cystic fibrosis (CF), can be corrected by cell incubation at low temperature, an effect that may be mediated by altered expression of proteostasis genes. METHODS To identify small molecules mimicking low temperature, we compared gene expression profiles of cells kept at 27°C with those previously generated from more than 1300 compounds. The resulting candidates were tested with a functional assay on a bronchial epithelial cell line. RESULTS We found that anti-inflammatory glucocorticoids, such as mometasone, budesonide, and fluticasone, increased mutant CFTR function. However, this activity was not confirmed in primary bronchial epithelial cells. Actually, glucocorticoids enhanced Na(+) absorption, an effect that could further impair mucociliary clearance in CF airways. CONCLUSIONS Our results suggest that rescue of F508del-CFTR by low temperature cannot be easily mimicked by small molecules and that compounds with closer transcriptional and functional effects need to be found.
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Affiliation(s)
- Emanuela Pesce
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | - Giulia Gorrieri
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | - Francesco Sirci
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Francesco Napolitano
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Diego Carrella
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Emanuela Caci
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | - Valeria Tomati
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
| | | | - Diego di Bernardo
- Telethon Institute of Genetics and Medicine, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| | - Luis J V Galietta
- Istituto Giannina Gaslini, via Gerolamo Gaslini 5, 16147 Genova, Italy
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50
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Whitlock JM, Hartzell HC. A Pore Idea: the ion conduction pathway of TMEM16/ANO proteins is composed partly of lipid. Pflugers Arch 2016; 468:455-73. [PMID: 26739711 PMCID: PMC4751199 DOI: 10.1007/s00424-015-1777-2] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/14/2015] [Accepted: 12/16/2015] [Indexed: 01/04/2023]
Abstract
Since their first descriptions, ion channels have been conceived as proteinaceous conduits that facilitate the passage of ionic cargo between segregated environments. This concept is reinforced by crystallographic structures of cation channels depicting ion conductance pathways completely lined by protein. Although lipids are sometimes present in fenestrations near the pore or may be involved in channel gating, there is little or no evidence that lipids inhabit the ion conduction pathway. Indeed, the presence of lipid acyl chains in the conductance pathway would curse the design of the channel's aqueous pore. Here, we make a speculative proposal that anion channels in the TMEM16/ANO superfamily have ion conductance pathways composed partly of lipids. Our reasoning is based on the idea that TMEM16 ion channels evolved from a kind of lipid transporter that scrambles lipids between leaflets of the membrane bilayer and the modeled structural similarity between TMEM16 lipid scramblases and TMEM16 anion channels. This novel view of the TMEM16 pore offers explanation for the biophysical and pharmacological oddness of TMEM16A. We build upon the recent X-ray structure of nhTMEM16 and develop models of both TMEM16 ion channels and lipid scramblases to bolster our proposal. It is our hope that this model of the TMEM16 pore will foster innovative investigation into TMEM16 function.
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Affiliation(s)
- Jarred M Whitlock
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - H Criss Hartzell
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA.
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