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Hu T, Li C, Wang T, Liu H, Geng J, Gong A. Serum osmolality was non-linearly associated with the risk of all-cause and cardiovascular mortality in patients with diabetes. BMJ Open Diabetes Res Care 2023; 11:e003826. [PMID: 38135453 DOI: 10.1136/bmjdrc-2023-003826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/06/2023] [Indexed: 12/24/2023] Open
Abstract
AIMS This study aimed to evaluate the relationship between both low and high osmolarity and the risk of all-cause and cause-specific mortality in diabetic population. METHODS All participants were included from the National Health and Nutrition Examination Survey 1999-2014. Baseline serum osmolality was determined from laboratory tests and cause of death from national death records. HRs and 95% CIs for all-cause mortality and cardiovascular mortality in diabetes were estimated using Cox proportional regression analysis. The non-linear relationship was explored using restricted cubic splines regression. RESULTS Among 7622 individuals with diabetes, 1983 (12.4%) died during a total of 3.26 thousand person-years of follow-up. Compared with the reference category (281-284 mmol/kg), the multivariable-adjusted HRs and 95% CIs for all-cause mortality were 1.27 (1.16-1.40; p<0.001) in the lowest osmolality category (<201 mmol/kg) and 1.18 (1.09-1.28; p<0.001) in the highest osmolality category (>312 mmol/kg). Restricted cubic splines results showed that serum levels of osmolality had a U-shaped association with the risk of all-cause mortality, and L-shaped relationship with the risk of cardiovascular death. CONCLUSIONS Both low osmolality and high osmolality were predictive of increased all-cause mortality in patients with diabetes, supporting a U-shaped relationship. Also, a lower serum osmolality increased the risk of cardiovascular mortality.
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Affiliation(s)
- Tingting Hu
- Departmet of Cardiology, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an 223300, Jiangsu, China
| | - Chenglin Li
- Department of Cardiothoracic Surgery, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu, China
| | - Tao Wang
- Jiangsu College of Nursing, Huai'an, Jiangsu, China
| | - Hailang Liu
- Departmet of Cardiology, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an 223300, Jiangsu, China
| | - Jin Geng
- Departmet of Cardiology, The Affiliated Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an 223300, Jiangsu, China
| | - Aifeng Gong
- Department of General Practice, The Affiliated Hospital Huai'an No.1 People's Hospital of Nanjing Medical University, Huai'an, Jiangsu, China
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2
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Abstract
The with no lysine (K) (WNK) kinases are an evolutionarily ancient group of kinases with atypical placement of the catalytic lysine and diverse physiological roles. Recent studies have shown that WNKs are directly regulated by chloride, potassium, and osmotic pressure. Here, we review the discovery of WNKs as chloride-sensitive kinases and discuss physiological contexts in which chloride regulation of WNKs has been demonstrated. These include the kidney, pancreatic duct, neurons, and inflammatory cells. We discuss the interdependent relationship of osmotic pressure and intracellular chloride in cell volume regulation. We review the recent demonstration of potassium regulation of WNKs and speculate on possible physiological roles. Finally, structural and mechanistic aspects of intracellular ion and osmotic pressure regulation of WNKs are discussed.
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Affiliation(s)
- Elizabeth J Goldsmith
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Aylin R Rodan
- Molecular Medicine Program, University of Utah, Salt Lake City, Utah, USA; .,Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Department of Human Genetics, University of Utah, Salt Lake City, Utah, USA.,Medical Service, Veterans Affairs Salt Lake City Healthcare System, Salt Lake City, Utah, USA
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3
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A Cardioplegic Solution with an Understanding of a Cardiochannelopathy. Antioxidants (Basel) 2021; 10:antiox10121878. [PMID: 34942981 PMCID: PMC8698488 DOI: 10.3390/antiox10121878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2021] [Revised: 11/16/2021] [Accepted: 11/23/2021] [Indexed: 01/11/2023] Open
Abstract
Cardiac surgeries have been improved by accompanying developing cardioplegia solutions. However, the cardioplegia application presents an ongoing challenge with a view of a sufficiently restored cardiac function. In this review, we focus on the cardioplegia-induced mechanism and summarize the findings of studies undertaken to improve cardioprotective strategies. Currently, and somewhat surprisingly, relatively little is known about cardiac electrolyte regulation through channel physiology. We hope that an improved understanding of the electrolyte transport through ion channels/transporters and modulations of water channel aquaporins will provide an insight into cardiac channel physiology and a channel-based cardiac pathology of a cardiochannelopathy.
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4
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Shiozaki A, Konishi T, Kosuga T, Kudou M, Kurashima K, Inoue H, Shoda K, Arita T, Konishi H, Morimura R, Komatsu S, Ikoma H, Toma A, Kubota T, Fujiwara H, Okamoto K, Otsuji E. Roles of voltage‑gated potassium channels in the maintenance of pancreatic cancer stem cells. Int J Oncol 2021; 59:76. [PMID: 34414448 PMCID: PMC8425586 DOI: 10.3892/ijo.2021.5256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 06/16/2021] [Indexed: 11/10/2022] Open
Abstract
The targeting of membrane proteins that are activated in cancer stem cells (CSCs) represents one of the key recent strategies in cancer therapy. The present study analyzed ion channel expression profiles and functions in pancreatic CSCs (PCSCs). Cells strongly expressing aldehyde dehydrogenase 1 family member A1 (ALDH1A1) were isolated from the human pancreatic PK59 cell line using fluorescence-activated cell sorting, and PCSCs were identified based on tumorsphere formation. Microarray analysis was performed to investigate the gene expression profiles in PCSCs. ALDH1A1 messenger RNA levels were higher in PCSCs compared with non-PCSCs. PCSCs were resistant to 5-fluorouracil and capable of redifferentiation. The results of the microarray analysis revealed that gene expression related to ion channels, including voltage-gated potassium channels (Kv), was upregulated in PCSCs compared with non-PCSCs. 4-Aminopyridine (4-AP), a potent Kv inhibitor, exhibited greater cytotoxicity in PCSCs compared with non-PCSCs. In a xenograft model in nude mice, tumor volumes were significantly lower in mice inoculated with PK59 cells pre-treated with 4-AP compared with those in mice injected with non-treated cells. The present results identified a role of Kv in the persistence of PCSCs and suggested that the Kv inhibitor 4-AP may have potential as a therapeutic agent for pancreatic carcinoma.
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Affiliation(s)
- Atsushi Shiozaki
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Tomoki Konishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Toshiyuki Kosuga
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Michihiro Kudou
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Kento Kurashima
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Hiroyuki Inoue
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Katsutoshi Shoda
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Tomohiro Arita
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Hirotaka Konishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Ryo Morimura
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Shuhei Komatsu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Hisashi Ikoma
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Atsushi Toma
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Takeshi Kubota
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Hitoshi Fujiwara
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Kazuma Okamoto
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
| | - Eigo Otsuji
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602‑8566, Japan
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5
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Mayes-Hopfinger L, Enache A, Xie J, Huang CL, Köchl R, Tybulewicz VLJ, Fernandes-Alnemri T, Alnemri ES. Chloride sensing by WNK1 regulates NLRP3 inflammasome activation and pyroptosis. Nat Commun 2021; 12:4546. [PMID: 34315884 PMCID: PMC8316491 DOI: 10.1038/s41467-021-24784-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 06/30/2021] [Indexed: 01/05/2023] Open
Abstract
The NLRP3 inflammasome mediates the production of proinflammatory cytokines and initiates inflammatory cell death. Although NLRP3 is essential for innate immunity, aberrant NLRP3 inflammasome activation contributes to a wide variety of inflammatory diseases. Understanding the pathways that control NLRP3 activation will help develop strategies to treat these diseases. Here we identify WNK1 as a negative regulator of the NLRP3 inflammasome. Macrophages deficient in WNK1 protein or kinase activity have increased NLRP3 activation and pyroptosis compared with control macrophages. Mice with conditional knockout of WNK1 in macrophages have increased IL-1β production in response to NLRP3 stimulation compared with control mice. Mechanistically, WNK1 tempers NLRP3 activation by balancing intracellular Cl- and K+ concentrations during NLRP3 activation. Collectively, this work shows that the WNK1 pathway has a critical function in suppressing NLRP3 activation and suggests that pharmacological inhibition of this pathway to treat hypertension might have negative clinical implications.
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Affiliation(s)
- Lindsey Mayes-Hopfinger
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Aura Enache
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Jian Xie
- Department of Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Chou-Long Huang
- Department of Medicine, Division of Nephrology, University of Iowa Carver College of Medicine, Iowa City, IA, USA
| | - Robert Köchl
- The Francis Crick Institute, London, UK
- Kings College London, London, UK
| | | | - Teresa Fernandes-Alnemri
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Emad S Alnemri
- Department of Biochemistry and Molecular Biology, Thomas Jefferson University, Philadelphia, PA, USA.
- Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA.
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6
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Touchard A, Mendel HC, Boulogne I, Herzig V, Braga Emidio N, King GF, Triquigneaux M, Jaquillard L, Beroud R, De Waard M, Delalande O, Dejean A, Muttenthaler M, Duplais C. Heterodimeric Insecticidal Peptide Provides New Insights into the Molecular and Functional Diversity of Ant Venoms. ACS Pharmacol Transl Sci 2020; 3:1211-1224. [PMID: 33344898 DOI: 10.1021/acsptsci.0c00119] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Indexed: 12/14/2022]
Abstract
Ants use venom for predation, defense, and communication; however, the molecular diversity, function, and potential applications of ant venom remains understudied compared to other venomous lineages such as arachnids, snakes and cone snails. In this work, we used a multidisciplinary approach that encompassed field work, proteomics, sequencing, chemical synthesis, structural analysis, molecular modeling, stability studies, and in vitro and in vivo bioassays to investigate the molecular diversity of the venom of the Amazonian Pseudomyrmex penetrator ants. We isolated a potent insecticidal heterodimeric peptide Δ-pseudomyrmecitoxin-Pp1a (Δ-PSDTX-Pp1a) composed of a 27-residue long A-chain and a 33-residue long B-chain cross-linked by two disulfide bonds in an antiparallel orientation. We chemically synthesized Δ-PSDTX-Pp1a, its corresponding parallel AA and BB homodimers, and its monomeric chains and demonstrated that Δ-PSDTX-Pp1a had the most potent insecticidal effects in blowfly assays (LD50 = 3 nmol/g). Molecular modeling and circular dichroism studies revealed strong α-helical features, indicating its cytotoxic effects could derive from cell membrane pore formation or disruption. The native heterodimer was substantially more stable against proteolytic degradation (t 1/2 = 13 h) than its homodimers or monomers (t 1/2 < 20 min), indicating an evolutionary advantage of the more complex structure. The proteomic analysis of Pseudomyrmex penetrator venom and in-depth characterization of Δ-PSDTX-Pp1a provide novel insights in the structural complexity of ant venom and further exemplifies how nature exploits disulfide-bond formation and dimerization to gain an evolutionary advantage via improved stability, a concept that is highly relevant for the design and development of peptide therapeutics, molecular probes, and bioinsecticides.
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Affiliation(s)
- Axel Touchard
- CNRS, UMR Ecofog, AgroParisTech, Cirad, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
| | - Helen C Mendel
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Isabelle Boulogne
- Université de ROUEN, UFR des Sciences et Techniques, Laboratoire Glycobiologie et Matrice Extracellulaire Végétale, UPRES-EA 4358, Fédération de Recherche Normandie Végétal FED 4277, Mont-Saint-Aignan 76821, France
| | - Volker Herzig
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia.,GeneCology Research Centre, School of Science, Technology and Engineering, University of the Sunshine Coast, Sippy Downs, Queensland 4556, Australia
| | - Nayara Braga Emidio
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | - Glenn F King
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia
| | | | - Lucie Jaquillard
- Smartox Biotechnology, 6 rue des Platanes, Saint Egrève 38120, France
| | - Rémy Beroud
- Smartox Biotechnology, 6 rue des Platanes, Saint Egrève 38120, France
| | - Michel De Waard
- Smartox Biotechnology, 6 rue des Platanes, Saint Egrève 38120, France.,Université de Nantes, CNRS, INSERM, L'institut du thorax, Nantes 44000, France.,LabEx, Ion Channels, Science & Therapeutics, Valbonne 06560, France
| | - Olivier Delalande
- Institute of Genetics and Development of Rennes (IGDR), CNRS UMR 6290, Université de Rennes Faculté de Pharmacie, 2 avenue du Professeur Léon Bernard, Rennes 35043, France
| | - Alain Dejean
- CNRS, UMR Ecofog, AgroParisTech, Cirad, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France.,Ecolab, Université de Toulouse, CNRS, INPT, UPS, Toulouse 31058, France
| | - Markus Muttenthaler
- Institute for Molecular Bioscience, The University of Queensland, St. Lucia, Queensland 4072, Australia.,Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Vienna 1090, Austria
| | - Christophe Duplais
- CNRS, UMR Ecofog, AgroParisTech, Cirad, INRAE, Université des Antilles, Université de Guyane, Kourou 97310, France
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7
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Katsurahara K, Shiozaki A, Kosuga T, Kudou M, Shoda K, Arita T, Konishi H, Komatsu S, Kubota T, Fujiwara H, Okamoto K, Kishimoto M, Konishi E, Marunaka Y, Otsuji E. ANO9 Regulated Cell Cycle in Human Esophageal Squamous Cell Carcinoma. Ann Surg Oncol 2020; 27:3218-3230. [PMID: 32227267 DOI: 10.1245/s10434-020-08368-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Indexed: 12/14/2022]
Abstract
BACKGROUND Few studies have reported the function and activation mechanism of ANO9 in esophageal squamous cell carcinoma (ESCC). The current study aimed to investigate the role of ANO9 in the regulation of tumor progression. METHODS Knockdown experiments with human ESCC cell lines were performed using ANO9 siRNA, and the effects on cell proliferation, the cell cycle, apoptosis, and cellular movement were analyzed. Immunohistochemistry (IHC) analysis was performed on 57 primary tumor samples obtained from ESCC patients. RESULTS In an in vitro study, depletion of ANO9 reduced cell proliferation, invasion, and migration in KYSE150 and KYSE 790 cells. In the cell cycle analysis, depletion of ANO9 increased the number of cells in G0/G1 arrest. In addition, the knockdown of ANO9 increased apoptosis. The results of the microarray analysis indicated that various centrosome-related genes such as CEP120, CNTRL, and SPAST were up- or downregulated in ANO9-depleted KYSE150 cells. The IHC results showed that high expression of ANO9 was associated with poor prognosis. CONCLUSIONS The results of the current study suggest that ANO9 regulates the cell cycle via centrosome-related genes in ESCC.
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Affiliation(s)
- Keita Katsurahara
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Atsushi Shiozaki
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan.
| | - Toshiyuki Kosuga
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Michihiro Kudou
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Katsutoshi Shoda
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomohiro Arita
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hirotaka Konishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shuhei Komatsu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Takeshi Kubota
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hitoshi Fujiwara
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazuma Okamoto
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Mitsuo Kishimoto
- Department of Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Eiichi Konishi
- Department of Pathology, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan.,Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, Ritsumeikan University, Kusatsu, Japan.,International Research Center for Food Nutrition and Safety, College of Food and Biological Engineering, Jiangsu University, Zhenjiang, China
| | - Eigo Otsuji
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
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8
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Abstract
Cl- is the major extracellular (Cl-out) and intracellular (Cl-in) anion whose concentration is actively regulated by multiple transporters. These transporters generate Cl- gradients across the plasma membrane and between the cytoplasm and intracellular organelles. [Cl-]in changes rapidly in response to cell stimulation and influences many physiological functions, as well as cellular and systemic homeostasis. However, less appreciated is the signaling function of Cl-. Cl- interacts with multiple proteins to directly modify their activity. This review highlights the signaling function of Cl- and argues that Cl- is a bona fide signaling ion, a function deserving extensive exploration.
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Affiliation(s)
- Benjamin P Lüscher
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Laura Vachel
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
| | - Ehud Ohana
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer-Sheva, Israel
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland
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9
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Lu P, Ding Q, Li X, Ji X, Li L, Fan Y, Xia Y, Tian D, Liu M. SWELL1 promotes cell growth and metastasis of hepatocellular carcinoma in vitro and in vivo. EBioMedicine 2019; 48:100-116. [PMID: 31597595 PMCID: PMC6838441 DOI: 10.1016/j.ebiom.2019.09.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 12/20/2022] Open
Abstract
Background SWELL1 was recently demonstrated to be an indispensable part of the volume-regulated anion channel (VRAC). VRAC is reported to participate in cell proliferation, survival, and migration. However, the correlation between SWELL1 and hepatocellular carcinoma (HCC) remains poorly-understood. In this study, we tried to explore the role of SWELL1 in HCC. Methods Immunohistochemistry and quantitative real-time-PCR (qRT-PCR) was used to measure SWELL1 expression in HCC samples obtained from patients with HCC. The effects of SWELL1 on HCC cell proliferation, apoptosis, and metastasis were analysed by corresponding cytological experiments including Cell Counting Kit-8 (CCK8), colony-forming, 5-ethynyl-2′-deoxyuridine (EdU), cell cycle analysis, TUNEL, Annexin V and PI staining, wound healing, transwell, and so on. BALB/c nude mice were used for the in vivo assays. qRT-PCR and western blotting was performed for molecular mechanisms. Findings SWELL1 was highly expressed in HCC tissues, and related to the poor prognosis. In vitro, the over-expression of SWELL1 significantly induced cell proliferation and migration, and inhibited apoptosis, whereas suppressing SWELL1 had the opposite effects. Moreover, knockdown of SWELL1 suppressed the growth and metastasis of HCC in vivo. Further experiments revealed that SWELL1 induced cell growth by activating the cyclinD1/CDK2 pathway via the connection with PKCa at the signalling level, and regulated cell migration through the JNK pathway in HCC. Interpretation SWELL1 acts as a promoter in the growth and metastasis of HCC cells and may be a potential intervention target for HCC. Fund This work is supported by the National Natural Science Foundation of China (No. 81572422, 81700515).
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Affiliation(s)
- Panpan Lu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Qiang Ding
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Xin Li
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Xiaoyu Ji
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Lili Li
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Yuhui Fan
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China; Department of Gastroenterology, Internal Medicine II, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Yujia Xia
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Dean Tian
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China
| | - Mei Liu
- Department of Gastroenterology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei Province, China.
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10
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Shiozaki A, Yamazato Y, Kosuga T, Kudou M, Shoda K, Arita T, Konishi H, Komatsu S, Kubota T, Fujiwara H, Okamoto K, Marunaka Y, Otsuji E. Effect of low temperature on the regulation of cell volume after hypotonic shock in gastric cancer cells. Int J Oncol 2019; 55:905-914. [PMID: 31432150 DOI: 10.3892/ijo.2019.4853] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Accepted: 06/20/2019] [Indexed: 11/05/2022] Open
Abstract
Although peritoneal lavage with distilled water performed after surgery prevents peritoneal seeding, cancer cells may avoid rupture under mild hypotonicity through regulatory volume decrease (RVD), which is the homeostatic regulation of ion and water transport. The aim of the present study was to investigate the effect of low temperature on cell volume and cell death under hypoosmolal conditions and determine the underlying molecular mechanisms in gastric cancer (GC). Three human GC cell lines (NUGC4, KATO‑III and MKN45) were exposed to hypotonic solutions, and the effects of low temperature on cell volume and viability were examined. Low temperature‑induced changes in membrane transporters were evaluated, and knockdown and overexpression experiments were conducted to determine their effects on cell volume during hypotonic stimulation. Low temperature (24˚C) during hypotonic stimulation inhibited RVD and enhanced the cytocidal effects on GC cells. The expression of leucine‑rich repeat containing protein A (LRRC8A), a component of a Cl‑ channel, was decreased, and aquaporin 5 (AQP5) expression was increased at low temperatures. LRRC8A knockdown markedly slowed the decrease in cell volume following cell swelling by hypotonic shock. AQP5 overexpression enhanced initial cell swelling after hypotonic shock and increased the final cell volume. These results suggest that a hypotonic solution at low temperature increased initial water influx via activation of AQP5 and decreased Cl‑ efflux via inhibition of LRRC8A. Therefore, low temperature enhanced the hypotonicity‑induced cytocidal effects on GC cells, and these results may contribute to the development of a novel lavage method effective in reducing peritoneal recurrence in GC.
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Affiliation(s)
- Atsushi Shiozaki
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Yuzo Yamazato
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Toshiyuki Kosuga
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Michihiro Kudou
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Katsutoshi Shoda
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Tomohiro Arita
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Hirotaka Konishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Shuhei Komatsu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Takeshi Kubota
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Hitoshi Fujiwara
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Kazuma Okamoto
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
| | - Eigo Otsuji
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Kyoto 602‑8566, Japan
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11
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Inui TA, Yasuda M, Hirano S, Ikeuchi Y, Kogiso H, Inui T, Marunaka Y, Nakahari T. Enhancement of ciliary beat amplitude by carbocisteine in ciliated human nasal epithelial cells. Laryngoscope 2019; 130:E289-E297. [PMID: 31294840 DOI: 10.1002/lary.28185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 05/29/2019] [Accepted: 06/24/2019] [Indexed: 12/15/2022]
Abstract
OBJECTIVE Carbocisteine (CCis), a mucoactive agent, is used to improve the symptoms of sinonasal diseases. However, the effect of CCis on nasal ciliary beating remains uncertain. We examined the effects of CCis on ciliary beat distance (CBD, an index of amplitude), and ciliary beat frequency (CBF) in ciliated human nasal epithelial cells (cHNECs) in primary culture. METHODS The cHNECs were prepared from the nasal tissue resected from patients required surgery for chronic sinusitis (CS) or allergic rhinitis (AR). CBD and CBF were measured using videomicroscopy equipped with a high-speed camera. RESULTS CCis increased CBD by 30%, but not CBF, and decreased intracellular Cl- concentration ([Cl- ]i ) in cHNECs. The CCis' actions were mimicked by the Cl- -free NO3 - solution. In contrast, prior treatment of NPPB (20 μM) or CFTR(inh)-172 (1 μM), which increased [Cl- ]i by 20%, decreased CBF by 10% and CBD by 25% and inhibited the CCis' actions. However, prior treatment of T16Ainh-A01 (10 μM) did not inhibit the CCis' actions, although it decreased [Cl- ]i by 10% and CBD by 15%. Thus, CCis stimulates Cl- channels including cystic fibrosis transmembrane conductance regulator (CFTR). Moreover, CCis enhanced the transport of microbeads driven by the beating cilia in cHNECs. The CCis actions were similar in cHNECs from both types of pateints. CONCLUSION CCis increased CBD by 30% in cHNECs via an [Cl- ]i decrease stimulated by activation of Cl- channels, including CFTR. CCis may stimulate nasal mucociliary clearance by increasing CBD in patients contracting CS or AR. LEVEL OF EVIDENCE NA. Laryngoscope, 130:E289-E297, 2020.
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Affiliation(s)
- Taka-Aki Inui
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Makoto Yasuda
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shigeru Hirano
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yukiko Ikeuchi
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Haruka Kogiso
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Toshio Inui
- Research Laboratory for Epithelial Physiology, Research Organization of Science and Technology, BKC, Ritsumeikan University, Kusatsu, Japan.,Saisei Mirai Clinics, Moriguchi, Japan
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Research Laboratory for Epithelial Physiology, Research Organization of Science and Technology, BKC, Ritsumeikan University, Kusatsu, Japan.,Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto, Japan
| | - Takashi Nakahari
- Research Laboratory for Epithelial Physiology, Research Organization of Science and Technology, BKC, Ritsumeikan University, Kusatsu, Japan
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12
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Inui TA, Yasuda M, Hirano S, Ikeuchi Y, Kogiso H, Inui T, Marunaka Y, Nakahari T. Daidzein-Stimulated Increase in the Ciliary Beating Amplitude via an [Cl -] i Decrease in Ciliated Human Nasal Epithelial Cells. Int J Mol Sci 2018; 19:ijms19123754. [PMID: 30486295 PMCID: PMC6321431 DOI: 10.3390/ijms19123754] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/22/2018] [Accepted: 11/22/2018] [Indexed: 01/26/2023] Open
Abstract
The effects of the isoflavone daidzein on the ciliary beat distance (CBD, which is a parameter assessing the amplitude of ciliary beating) and the ciliary beat frequency (CBF) were examined in ciliated human nasal epithelial cells (cHNECs) in primary culture. Daidzein decreased [Cl−]i and enhanced CBD in cHNECs. The CBD increase that was stimulated by daidzein was mimicked by Cl−-free NO3− solution and bumetanide (an inhibitor of Na+/K+/2Cl− cotransport), both of which decreased [Cl−]i. Moreover, the CBD increase was inhibited by 5-Nitro-2-(3-phenylpropylamino)benzoic acid (NPPB, a Cl− channel blocker), which increased [Cl−]i. CBF was also decreased by NPPB. The rate of [Cl−]i decrease evoked by Cl−-free NO3− solution was enhanced by daidzein. These results suggest that daidzein activates Cl− channels in cHNECs. Moreover, daidzein enhanced the microbead transport driven by beating cilia in the cell sheet of cHNECs, suggesting that an increase in CBD enhances ciliary transport. An [Cl−]i decrease enhanced CBD, but not CBF, in cHNECs at 37 °C, although it enhanced both at 25 °C. Intracellular Cl− affects both CBD and CBF in a temperature-dependent manner. In conclusion, daidzein, which activates Cl− channels to decrease [Cl−]i, stimulated CBD increase in cHNECs at 37 °C. CBD is a crucial factor that can increase ciliary transport in the airways under physiological conditions.
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Affiliation(s)
- Taka-Aki Inui
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Makoto Yasuda
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Shigeru Hirano
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Yukiko Ikeuchi
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Haruka Kogiso
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
| | - Toshio Inui
- Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, BKC, Ritsumeikan University, Kusatsu 525-8577, Japan.
- Saisei Mirai Clinics, Moriguchi 570-0012, Japan.
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
- Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, BKC, Ritsumeikan University, Kusatsu 525-8577, Japan.
- Research Institute for Clinical Physiology, Kyoto Industrial Health Association, Kyoto 604-8472, Japan.
| | - Takashi Nakahari
- Research Center for Drug Discovery and Pharmaceutical Development Science, Research Organization of Science and Technology, BKC, Ritsumeikan University, Kusatsu 525-8577, Japan.
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13
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Vachel L, Shcheynikov N, Yamazaki O, Fremder M, Ohana E, Son A, Shin DM, Yamazaki-Nakazawa A, Yang CR, Knepper MA, Muallem S. Modulation of Cl - signaling and ion transport by recruitment of kinases and phosphatases mediated by the regulatory protein IRBIT. Sci Signal 2018; 11:11/554/eaat5018. [PMID: 30377224 DOI: 10.1126/scisignal.aat5018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
IRBIT is a multifunctional protein that controls the activity of various epithelial ion transporters including NBCe1-B. Interaction with IRBIT increases NBCe1-B activity and exposes two cryptic Cl--sensing GXXXP sites that enable regulation of NBCe1-B by intracellular Cl- (Cl- in). Here, phosphoproteomic analysis revealed that IRBIT controlled five phosphorylation sites in NBCe1-B that determined both the active conformation of the transporter and its regulation by Cl- in Mutational analysis suggested that the phosphorylation status of Ser232, Ser233, and Ser235 was regulated by IRBIT and determined whether NBCe1 transporters are in active or inactive conformations. The absence of phosphorylation at Ser232, Ser233, or Ser235 produced NBCe1-B in the conformations pSer233/pSer235, pSer232/pSer235, or pSer232/pSer233, respectively. The activity of the pSer233/pSer235 form was similar to that of IRBIT-activated NBCe1-B, but it was insensitive to inhibition by Cl- in The properties of the pSer232/pSer235 form were similar to those of wild-type NBCe1-B, whereas the pSer232/pSer233 form was partially active, further activated by IRBIT, but retained inhibition by Cl- in Furthermore, IRBIT recruited the phosphatase PP1 and the kinase SPAK to control phosphorylation of Ser65, which affected Cl- in sensing by the 32GXXXP36 motif. IRBIT also recruited the phosphatase calcineurin and the kinase CaMKII to control phosphorylation of Ser12, which affected Cl- in sensing by the 194GXXXP198 motif. Ser232, Ser233, and Ser235 are conserved in all NBCe1 variants and affect their activity. These findings reveal how multiple kinase and phosphatase pathways use phosphorylation sites to fine-tune a transporter, which have important implications for epithelial fluid and HCO3 - secretion.
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Affiliation(s)
- Laura Vachel
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Nikolay Shcheynikov
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Osamu Yamazaki
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.,Apheresis and Dialysis Center/General Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-0016, Japan
| | - Moran Fremder
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Ehud Ohana
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben Gurion University of the Negev, 84105 Beer Sheva, Israel
| | - Aran Son
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Dong Min Shin
- Department of Oral Biology, BK 21 PLUS Project, Yonsei University College of Dentistry, Seoul 120-752, Korea
| | - Ai Yamazaki-Nakazawa
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA
| | - Chin-Rang Yang
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Mark A Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Shmuel Muallem
- Epithelial Signaling and Transport Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD 20892, USA.
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14
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Rodan AR. WNK-SPAK/OSR1 signaling: lessons learned from an insect renal epithelium. Am J Physiol Renal Physiol 2018; 315:F903-F907. [PMID: 29923766 DOI: 10.1152/ajprenal.00176.2018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
WNK [with no lysine (K)] kinases regulate renal epithelial ion transport to maintain homeostasis of electrolyte concentrations, extracellular volume, and blood pressure. The SLC12 cation-chloride cotransporters, including the sodium-potassium-2-chloride (NKCC) and sodium chloride cotransporters (NCC), are targets of WNK regulation via the intermediary kinases SPAK (Ste20-related proline/alanine-rich kinase) and OSR1 (oxidative stress response). The pathway is activated by low dietary potassium intake, resulting in increased phosphorylation and activity of NCC. Chloride regulates WNK kinases in vitro by binding to the active site and inhibiting autophosphorylation and has been proposed to modulate WNK activity in the distal convoluted tubule in response to low dietary potassium. WNK-SPAK/OSR1 regulation of NKCC-dependent ion transport is evolutionarily ancient, and it occurs in the Drosophila Malpighian (renal) tubule. Here, we review recent studies from the Drosophila tubule demonstrating cooperative roles for chloride and the scaffold protein Mo25 (mouse protein-25, also known as calcium-binding protein-39) in the regulation of WNK-SPAK/OSR1 signaling in a transporting renal epithelium. Insights gained from this genetically manipulable and physiologically accessible epithelium shed light on molecular mechanisms of regulation of the WNK-SPAK/OSR1 pathway, which is important in human health and disease.
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Affiliation(s)
- Aylin R Rodan
- Department of Internal Medicine, Division of Nephrology and Hypertension, Molecular Medicine Program, University of Utah , Salt Lake City, Utah
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15
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Sun Q, Wu Y, Jonusaite S, Pleinis JM, Humphreys JM, He H, Schellinger JN, Akella R, Stenesen D, Krämer H, Goldsmith EJ, Rodan AR. Intracellular Chloride and Scaffold Protein Mo25 Cooperatively Regulate Transepithelial Ion Transport through WNK Signaling in the Malpighian Tubule. J Am Soc Nephrol 2018; 29:1449-1461. [PMID: 29602832 DOI: 10.1681/asn.2017101091] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 02/07/2018] [Indexed: 12/17/2022] Open
Abstract
Background With No Lysine kinase (WNK) signaling regulates mammalian renal epithelial ion transport to maintain electrolyte and BP homeostasis. Our previous studies showed a conserved role for WNK in the regulation of transepithelial ion transport in the Drosophila Malpighian tubule.Methods Using in vitro assays and transgenic Drosophila lines, we examined two potential WNK regulators, chloride ion and the scaffold protein mouse protein 25 (Mo25), in the stimulation of transepithelial ion flux.ResultsIn vitro, autophosphorylation of purified Drosophila WNK decreased as chloride concentration increased. In conditions in which tubule intracellular chloride concentration decreased from 30 to 15 mM as measured using a transgenic sensor, Drosophila WNK activity acutely increased. Drosophila WNK activity in tubules also increased or decreased when bath potassium concentration decreased or increased, respectively. However, a mutation that reduces chloride sensitivity of Drosophila WNK failed to alter transepithelial ion transport in 30 mM chloride. We, therefore, examined a role for Mo25. In in vitro kinase assays, Drosophila Mo25 enhanced the activity of the Drosophila WNK downstream kinase Fray, the fly homolog of mammalian Ste20-related proline/alanine-rich kinase (SPAK), and oxidative stress-responsive 1 protein (OSR1). Knockdown of Drosophila Mo25 in the Malpighian tubule decreased transepithelial ion flux under stimulated but not basal conditions. Finally, whereas overexpression of wild-type Drosophila WNK, with or without Drosophila Mo25, did not affect transepithelial ion transport, Drosophila Mo25 overexpressed with chloride-insensitive Drosophila WNK increased ion flux.Conclusions Cooperative interactions between chloride and Mo25 regulate WNK signaling in a transporting renal epithelium.
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Affiliation(s)
- Qifei Sun
- Division of Nephrology, Department of Internal Medicine and
| | - Yipin Wu
- Division of Nephrology, Department of Internal Medicine and
| | - Sima Jonusaite
- Division of Nephrology and Hypertension, Department of Internal Medicine, Molecular Medicine Program, University of Utah, Salt Lake City, Utah
| | - John M Pleinis
- Division of Nephrology and Hypertension, Department of Internal Medicine, Molecular Medicine Program, University of Utah, Salt Lake City, Utah
| | | | | | | | | | - Drew Stenesen
- Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Helmut Krämer
- Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | | | - Aylin R Rodan
- Division of Nephrology, Department of Internal Medicine and .,Division of Nephrology and Hypertension, Department of Internal Medicine, Molecular Medicine Program, University of Utah, Salt Lake City, Utah
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16
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Ikeuchi Y, Kogiso H, Hosogi S, Tanaka S, Shimamoto C, Inui T, Nakahari T, Marunaka Y. Measurement of [Cl -] i unaffected by the cell volume change using MQAE-based two-photon microscopy in airway ciliary cells of mice. J Physiol Sci 2018; 68:191-199. [PMID: 29332212 PMCID: PMC10717022 DOI: 10.1007/s12576-018-0591-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 01/04/2018] [Indexed: 11/28/2022]
Abstract
MQAE is a 'non-ratiometric' chloride ion (Cl-)-quenched fluorescent indicator that is used to determine intracellular Cl- concentration ([Cl-]i). MQAE-based two-photon microscopy is reported to be a useful method to measure [Cl-]i, but it is still controversial because a change in cell volume may alter the MQAE concentration, leading to a change in the fluorescence intensity without any change in [Cl-]i. In an attempt to elucidate the effect or lack of effect of cell volume on MQAE concentration, we studied the effects of changes in cell volume, achieved by applying different levels of osmotic stress, on the intensity of MQAE fluorescence in airway ciliary cells. To study solely the effect of changes in cell volume on MQAE fluorescence intensity, i.e., excluding the effect of any change in [Cl-]i, we first conducted the experiments in a Cl--free nitrate (NO3-) solution to substitute NO3- (non-quenching anion for MQAE fluorescence) for Cl- in the intracellular fluid. Hypo- (- 30 mM NaNO3) or hyper-osmotic stress (+ 30 mM NaNO3) effected changes in cell volume, but the stress did not result in any significant change in MQAE fluorescence intensity. The experiments were also carried out in Cl--containing solution. Hypo-osmotic stress (- 30 mM NaCl) increased both MQAE fluorescence intensity and cell volume, while hyper-osmotic stress (+ 30 mM NaCl) decreased both of these properties. These results suggest that the osmotic stress-induced change in MQAE fluorescence intensity was caused by the change in [Cl-]i and not by the MQAE concentration. Moreover, the intracellular distribution of MQAEs was heterogeneous and not affected by the changes in osmotic stress-induced cell volume, suggesting that MQAEs are bound to un-identified subcellular structures. These bound MQAEs appear to have enabled the measurement of [Cl-]i in airway ciliary cells, even under conditions of cell volume change.
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Affiliation(s)
- Yukiko Ikeuchi
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Haruka Kogiso
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shigekuni Hosogi
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Saori Tanaka
- Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | - Chikao Shimamoto
- Laboratory of Pharmacotherapy, Osaka University of Pharmaceutical Sciences, Takatsuki, Japan
| | | | - Takashi Nakahari
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.
- Japan Institute for Food Education and Health, St Agnes' University, Kyoto, Japan.
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
- Japan Institute for Food Education and Health, St Agnes' University, Kyoto, Japan
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17
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Kosuga T, Shiozaki A, Kudou M, Yamazato Y, Ichikawa D, Komatsu S, Konishi H, Okamoto K, Shoda K, Arita T, Morimura R, Murayama Y, Kuriu Y, Ikoma H, Nakanishi M, Fujiwara H, Marunaka Y, Otsuji E. Blockade of potassium ion transports enhances hypotonicity-induced cytocidal effects in gastric cancer. Oncotarget 2017; 8:101394-101405. [PMID: 29254173 PMCID: PMC5731883 DOI: 10.18632/oncotarget.20736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Accepted: 08/07/2017] [Indexed: 01/01/2023] Open
Abstract
Background Peritoneal lavage with distilled water has been used for surgeries of various cancers to reduce peritoneal recurrence. This study examined whether blockade of potassium ion transports enhances hypotonicity-induced cytocidal effects in gastric cancer (GC). Results A potassium channel blocker inhibited the occurrence of regulatory volume decrease (RVD) induced by mild hypotonic stimulation, and significantly enhanced cytocidal effects on GC cells. Incubating MKN45 cells with hypotonic solutions containing a potassium channel blocker significantly reduced the formation of peritoneal metastases in nude mice. Methods The three human GC cell lines (HGC-27, Kato III, and MKN45) were exposed to mild hypotonic solutions, and the effects of blockade of potassium ion transports during hypotonic stimulation on cell volume changes and cell viabilities were examined. In the in vivo study, MKN45 cells stimulated with mild hypotonic solutions were intraperitoneally injected into nude mice, and the effects of blockade of potassium ion transports during hypotonic stimulation on the formation of peritoneal metastases were evaluated. Conclusions Blockade of potassium ion transports enhances hypotonicity-induced cytocidal effects on GC cells, which may contribute to development of a novel lavage method for further reduction of peritoneal recurrence in GC.
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Affiliation(s)
- Toshiyuki Kosuga
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Atsushi Shiozaki
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Michihiro Kudou
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yuzo Yamazato
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Daisuke Ichikawa
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Shuhei Komatsu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hirotaka Konishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Kazuma Okamoto
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Katsutoshi Shoda
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Tomohiro Arita
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Ryo Morimura
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yasutoshi Murayama
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshiaki Kuriu
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hisashi Ikoma
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Masayoshi Nakanishi
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Hitoshi Fujiwara
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan.,Japan Institute for Food Education and Health, St. Agnes' University, Kyoto, Japan
| | - Eigo Otsuji
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, Japan
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18
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Marunaka Y. The Mechanistic Links between Insulin and Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) Cl - Channel. Int J Mol Sci 2017; 18:ijms18081767. [PMID: 28805732 PMCID: PMC5578156 DOI: 10.3390/ijms18081767] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 07/31/2017] [Accepted: 08/10/2017] [Indexed: 12/30/2022] Open
Abstract
The cystic fibrosis transmembrane conductance regulator (CFTR) Cl− channel belongs to the ATP-binding cassette (ABC) transporter superfamily and regulates Cl− secretion in epithelial cells for water secretion. Loss-of-function mutations to the CFTR gene cause dehydrated mucus on the apical side of epithelial cells and increase the susceptibility of bacterial infection, especially in the airway and pulmonary tissues. Therefore, research on the molecular properties of CFTR, such as its gating mechanism and subcellular trafficking, have been intensively pursued. Dysregulated CFTR trafficking is one of the major pathological hallmarks in cystic fibrosis (CF) patients bearing missense mutations in the CFTR gene. Hormones that activate cAMP signaling, such as catecholamine, have been found to regulate the intracellular trafficking of CFTR. Insulin is one of the hormones that regulate cAMP production and promote trafficking of transmembrane proteins to the plasma membrane. The functional interactions between insulin and CFTR have not yet been clearly defined. In this review article, I review the roles of CFTR in epithelial cells, its regulatory role in insulin secretion, and a mechanism of CFTR regulation by insulin.
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Affiliation(s)
- Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan.
- Japan Institute for Food Education and Health, St. Agnes' University, Kyoto 602-8013, Japan.
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19
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Shiozaki A, Ichikawa D, Kosuga T, Marunaka Y, Otsuji E. Regulation of osmolality for cancer treatment. J Physiol Sci 2017; 67:353-360. [PMID: 28185236 PMCID: PMC10716996 DOI: 10.1007/s12576-017-0528-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Accepted: 01/23/2017] [Indexed: 02/08/2023]
Abstract
Disseminated metastasis is associated with a poor prognosis, and its management in the peritoneal or pleural cavity is crucial in the treatment of cancer. Recent studies show that ion and water transporters play important roles in fundamental cellular functions, including the regulation of cell volume that would be involved in the cancer process. Here, we review the evidence for hypotonic treatments of cancer and evaluate the potential of the cellular physiological approach in clinical management. The regulation of extracellular osmolality is a promising method, with several studies demonstrating the cytocidal effects of hypotonic solution on cancer cells. Peritoneal lavage with distilled water (DW) during surgery is reported to improve the survival rate of patients with spontaneously ruptured hepatocellular carcinoma. The in vitro studies included in this review also indicate the cytocidal effects of hypotonic shock on esophageal, gastric, colonic, pancreatic, and liver cancer cells with several unique methods and apparatuses, such as a differential interference contrast microscope connected to a digital video camera, a high-resolution flow cytometer and re-incubation analysis. The in vivo studies demonstrate the safeness of a peritoneal injection of DW into mice and indicate that the development of dissemination nodules can be prevented by the pre-incubation of cancer cells with DW or the peritoneal injection of DW. We also demonstrate that the blockade of Cl- channels/transporters enhances the cytocidal effects of hypotonic shock by inhibiting regulatory volume decrease in various cancer cells. A deeper understanding of molecular mechanisms may lead to the discovery of these cellular physiological approaches as a novel therapeutic strategy for disseminated metastasis.
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Affiliation(s)
- Atsushi Shiozaki
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan.
| | - Daisuke Ichikawa
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Toshiyuki Kosuga
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
| | - Yoshinori Marunaka
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan.
- Department of Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan.
- Japan Institute for Food Education and Health, St. Agnes' University, Kyoto, 602-8013, Japan.
| | - Eigo Otsuji
- Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, 465 Kajii-cho, Kamigyo-ku, Kyoto, 602-8566, Japan
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Nakajima KI, Marunaka Y. Intracellular chloride ion concentration in differentiating neuronal cell and its role in growing neurite. Biochem Biophys Res Commun 2016; 479:338-342. [DOI: 10.1016/j.bbrc.2016.09.075] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Accepted: 09/15/2016] [Indexed: 02/07/2023]
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21
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Kudou M, Shiozaki A, Kosuga T, Ichikawa D, Konishi H, Morimura R, Komatsu S, Ikoma H, Fujiwara H, Okamoto K, Hosogi S, Nakahari T, Marunaka Y, Otsuji E. Inhibition of Regulatory Volume Decrease Enhances the Cytocidal Effect of Hypotonic Shock in Hepatocellular Carcinoma. J Cancer 2016; 7:1524-33. [PMID: 27471568 PMCID: PMC4964136 DOI: 10.7150/jca.15181] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 06/04/2016] [Indexed: 12/16/2022] Open
Abstract
Background: Hypotonic shock induces cytocidal effects through cell rupture, and cancer therapy based on this mechanism has been clinically administered to hepatocellular carcinoma patients. We herein investigated the effectiveness of hypotonic shock combined with the inhibition of regulatory volume decrease as cancer therapy for hepatocellular carcinoma. Methods: Morphological changes in human hepatocellular carcinoma cell lines were observed under a differential interference contrast microscope connected to a high-speed digital video camera. Cell volume changes under hypotonic shock with or without chloride, potassium, or water channel blockers were observed using a high-resolution flow cytometer. In order to investigate cytocidal effects, the number of surviving cells was compared after exposure to hypotonic solution with and without each channel blocker (re-incubation experiment). Results: Video recordings showed that cells exposed to distilled water rapidly swelled and then ruptured. Cell volume measurements revealed regulatory volume decrease under mild hypotonic shock, whereas severe hypotonic shock increased the number of broken fragments as a result of cell rupture. Moreover, regulatory volume decrease was inhibited in cells treated with each channel blocker. Re-incubation experiments showed the cytocidal effects of hypotonic shock in cells exposed to hypotonic solution, and additional treatments with each channel blocker enhanced these effects. Conclusion: The inhibition of regulatory volume decrease with chloride, potassium, or water channel blockers may enhance the cytocidal effects of hypotonic shock in hepatocellular carcinoma. Hypotonic shock combined with the inhibition of regulatory volume decrease was a more effective therapy than hypotonic shock alone.
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Affiliation(s)
- Michihiro Kudou
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Atsushi Shiozaki
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Toshiyuki Kosuga
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Daisuke Ichikawa
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Hirotaka Konishi
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Ryo Morimura
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shuhei Komatsu
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Hisashi Ikoma
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Hitoshi Fujiwara
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Kazuma Okamoto
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Shigekuni Hosogi
- 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Takashi Nakahari
- 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
| | - Yoshinori Marunaka
- 2. Departments of Molecular Cell Physiology and Bio-Ionomics, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan;; 3. Japan Institute for Food Education and Health, Heian Jogakuin (St. Agnes') University, Kyoto, 602-8013, Japan
| | - Eigo Otsuji
- 1. Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto, 602-8566, Japan
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Paredes JM, Idilli AI, Mariotti L, Losi G, Arslanbaeva LR, Sato SS, Artoni P, Szczurkowska J, Cancedda L, Ratto GM, Carmignoto G, Arosio D. Synchronous Bioimaging of Intracellular pH and Chloride Based on LSS Fluorescent Protein. ACS Chem Biol 2016; 11:1652-60. [PMID: 27031242 DOI: 10.1021/acschembio.6b00103] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Ion homeostasis regulates critical physiological processes in the living cell. Intracellular chloride concentration not only contributes in setting the membrane potential of quiescent cells but it also plays a role in modulating the dynamic voltage changes during network activity. Dynamic chloride imaging demands new tools, allowing faster acquisition rates and correct accounting of concomitant pH changes. Joining a long-Stokes-shift red-fluorescent protein to a GFP variant with high sensitivity to pH and chloride, we obtained LSSmClopHensor, a genetically encoded fluorescent biosensor optimized for the simultaneous chloride and pH imaging and requiring only two excitation wavelengths (458 and 488 nm). LSSmClopHensor allowed us to monitor the dynamic changes of intracellular pH and chloride concentration during seizure like discharges in neocortical brain slices. Only cells with tightly controlled resting potential revealed a narrow distribution of chloride concentration peaking at about 5 and 8 mM, in neocortical neurons and SK-N-SH cells, respectively. We thus showed that LSSmClopHensor represents a new versatile tool for studying the dynamics of chloride and proton concentration in living systems.
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Affiliation(s)
- Jose M. Paredes
- Institute of Biophysics, CNR, Via
alla Cascata 56/C, 38123 Trento, Italy
- Bruno Kessler Foundation, Via
Sommarive 18, 38123 Trento, Italy
| | - Aurora I. Idilli
- Institute of Biophysics, CNR, Via
alla Cascata 56/C, 38123 Trento, Italy
| | - Letizia Mariotti
- Neuroscience Institute, CNR, Viale
G. Colombo 3, 35121 Padova, Italy
| | - Gabriele Losi
- Neuroscience Institute, CNR, Viale
G. Colombo 3, 35121 Padova, Italy
| | - Lyaysan R. Arslanbaeva
- Institute of Biophysics, CNR, Via
alla Cascata 56/C, 38123 Trento, Italy
- CIBIO, University of Trento, Via delle Regole 101, 38123 Trento, Italy
| | | | | | | | | | - Gian Michele Ratto
- Nanoscience Institute, CNR, Pisa, Italy
- Scuola Normale Superiore, Pisa, Italy
| | | | - Daniele Arosio
- Institute of Biophysics, CNR, Via
alla Cascata 56/C, 38123 Trento, Italy
- CIBIO, University of Trento, Via delle Regole 101, 38123 Trento, Italy
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23
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Kim N, Duncan GA, Hanes J, Suk JS. Barriers to inhaled gene therapy of obstructive lung diseases: A review. J Control Release 2016; 240:465-488. [PMID: 27196742 DOI: 10.1016/j.jconrel.2016.05.031] [Citation(s) in RCA: 78] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 05/11/2016] [Accepted: 05/12/2016] [Indexed: 12/29/2022]
Abstract
Knowledge of genetic origins of obstructive lung diseases has made inhaled gene therapy an attractive alternative to the current standards of care that are limited to managing disease symptoms. Initial lung gene therapy clinical trials occurred in the early 1990s following the discovery of the genetic defect responsible for cystic fibrosis (CF), a monogenic disorder. However, despite over two decades of intensive effort, gene therapy has yet to help patients with CF or any other obstructive lung disease. The slow progress is due in part to poor understanding of the biological barriers to inhaled gene therapy. Encouragingly, clinical trials have shown that inhaled gene therapy with various viral vectors and non-viral gene vectors is well tolerated by patients, and continued research has provided valuable lessons and resources that may lead to future success of this therapeutic strategy. In this review, we first introduce representative obstructive lung diseases and examine limitations of currently available therapeutic options. We then review key components for successful execution of inhaled gene therapy, including gene delivery systems, primary physiological barriers and strategies to overcome them, and advances in preclinical disease models with which the most promising systems may be identified for human clinical trials.
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Affiliation(s)
- Namho Kim
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Gregg A Duncan
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA
| | - Justin Hanes
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Environmental and Health Sciences, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Oncology, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Neurosurgery, Johns Hopkins University, Baltimore, MD 21205, USA; Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Jung Soo Suk
- The Center for Nanomedicine, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA; Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, MD 21231, USA.
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24
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Membrane transport: ionic environments, signal transduction, and development of therapeutic targets. BIOMED RESEARCH INTERNATIONAL 2015; 2015:581626. [PMID: 25954754 PMCID: PMC4410503 DOI: 10.1155/2015/581626] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 12/24/2014] [Accepted: 12/24/2014] [Indexed: 11/17/2022]
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25
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Intracellular Cl- as a signaling ion that potently regulates Na+/HCO3- transporters. Proc Natl Acad Sci U S A 2015; 112:E329-37. [PMID: 25561556 DOI: 10.1073/pnas.1415673112] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cl(-) is a major anion in mammalian cells involved in transport processes that determines the intracellular activity of many ions and plasma membrane potential. Surprisingly, a role of intracellular Cl(-) (Cl(-) in) as a signaling ion has not been previously evaluated. Here we report that Cl(-) in functions as a regulator of cellular Na(+) and HCO3 (-) concentrations and transepithelial transport through modulating the activity of several electrogenic Na(+)-HCO3 (-) transporters. We describe the molecular mechanism(s) of this regulation by physiological Cl(-) in concentrations highlighting the role of GXXXP motifs in Cl(-) sensing. Regulation of the ubiquitous Na(+)-HCO3(-) co-transport (NBC)e1-B is mediated by two GXXXP-containing sites; regulation of NBCe2-C is dependent on a single GXXXP motif; and regulation of NBCe1-A depends on a cryptic GXXXP motif. In the basal state NBCe1-B is inhibited by high Cl(-) in interacting at a low affinity GXXXP-containing site. IP3 receptor binding protein released with IP3 (IRBIT) activation of NBCe1-B unmasks a second high affinity Cl(-) in interacting GXXXP-dependent site. By contrast, NBCe2-C, which does not interact with IRBIT, has a single high affinity N-terminal GXXP-containing Cl(-) in interacting site. NBCe1-A is unaffected by Cl(-) in between 5 and 140 mM. However, deletion of NBCe1-A residues 29-41 unmasks a cryptic GXXXP-containing site homologous with the NBCe1-B low affinity site that is involved in inhibition of NBCe1-A by Cl(-) in. These findings reveal a cellular Cl(-) in sensing mechanism that plays an important role in the regulation of Na(+) and HCO3 (-) transport, with critical implications for the role of Cl(-) in cellular ion homeostasis and epithelial fluid and electrolyte secretion.
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26
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Wu Y, Schellinger JN, Huang CL, Rodan AR. Hypotonicity stimulates potassium flux through the WNK-SPAK/OSR1 kinase cascade and the Ncc69 sodium-potassium-2-chloride cotransporter in the Drosophila renal tubule. J Biol Chem 2014; 289:26131-26142. [PMID: 25086033 DOI: 10.1074/jbc.m114.577767] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The ability to osmoregulate is fundamental to life. Adult Drosophila melanogaster maintain hemolymph osmolarity within a narrow range. Osmolarity modulates transepithelial ion and water flux in the Malpighian (renal) tubules of the fly, which are in direct contact with hemolymph in vivo, but the mechanisms causing increased transepithelial flux in response to hypotonicity are unknown. Fly renal tubules secrete a KCl-rich fluid. We have previously demonstrated a requirement for Ncc69, the fly sodium-potassium-2-chloride cotransporter (NKCC), in tubule K(+) secretion. Mammalian NKCCs are regulated by a kinase cascade consisting of the with-no-lysine (WNK) and Ste20-related proline/alanine-rich (SPAK)/oxidative stress response (OSR1) kinases. Here, we show that decreasing Drosophila WNK activity causes a reduction in K(+) flux. Similarly, knocking down the SPAK/OSR1 homolog fray also decreases K(+) flux. We demonstrate that a hierarchical WNK-Fray signaling cascade regulates K(+) flux through Ncc69, because (i) a constitutively active Fray mutant rescues the wnk knockdown phenotype, (ii) Fray directly phosphorylates Ncc69 in vitro, and (iii) the effect of wnk and fray knockdown is abolished in Ncc69 mutants. The stimulatory effect of hypotonicity on K(+) flux is absent in wnk, fray, or Ncc69 mutant tubules, suggesting that the Drosophila WNK-SPAK/OSR1-NKCC cascade is an essential molecular pathway for osmoregulation, through its effect on transepithelial ion flux and fluid generation by the renal tubule.
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Affiliation(s)
- Yipin Wu
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856
| | - Jeffrey N Schellinger
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856
| | - Chou-Long Huang
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856
| | - Aylin R Rodan
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75390-8856.
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27
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Efficacy of a hypotonic treatment for peritoneal dissemination from gastric cancer cells: an in vivo evaluation. BIOMED RESEARCH INTERNATIONAL 2014; 2014:707089. [PMID: 25093178 PMCID: PMC4100448 DOI: 10.1155/2014/707089] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Accepted: 06/13/2014] [Indexed: 01/05/2023]
Abstract
The aim of the present study was to determine the efficacy of a hypotonic treatment for peritoneal dissemination from gastric cancer cells using an in vivo model. We firstly evaluated the toxicity of a peritoneal injection of distilled water (DW) (2 mL for 3 days) in mice. Macroscopic and microscopic examinations revealed that the peritoneal injection of DW did not severely damage the abdominal organs of these mice. MKN45 gastric cancer cells preincubated with NaCl buffer or DW for 20 minutes in vitro were then intraperitoneally injected into nude mice, and the development of dissemination nodules was analyzed. The total number, weight, and volume of the dissemination nodules were significantly decreased by the DW preincubation. We then determined whether the peritoneal injection of DW inhibited the establishment of peritoneal dissemination. After a peritoneal injection of MKN45 cells into nude mice, NaCl buffer or DW was injected into the abdominal cavity for 3 days. The total volume of dissemination nodules was significantly lower in DW-injected mice than in NaCl-injected mice. In conclusion, we demonstrated the safeness of a peritoneal injection of DW. Furthermore, the development of dissemination nodules from gastric cancer cells was prevented by a preincubation with or peritoneal injection of DW.
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28
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Piala AT, Moon TM, Akella R, He H, Cobb MH, Goldsmith EJ. Chloride sensing by WNK1 involves inhibition of autophosphorylation. Sci Signal 2014; 7:ra41. [PMID: 24803536 DOI: 10.1126/scisignal.2005050] [Citation(s) in RCA: 280] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
WNK1 [with no lysine (K)] is a serine-threonine kinase associated with a form of familial hypertension. WNK1 is at the top of a kinase cascade, leading to phosphorylation of several cotransporters, in particular those transporting sodium, potassium, and chloride (NKCC), sodium and chloride (NCC), and potassium and chloride (KCC). The responsiveness of NKCC, NCC, and KCC to changes in extracellular chloride parallels their phosphorylation state, provoking the proposal that these transporters are controlled by a chloride-sensitive protein kinase. We found that chloride stabilizes the inactive conformation of WNK1, preventing kinase autophosphorylation and activation. Crystallographic studies of inactive WNK1 in the presence of chloride revealed that chloride binds directly to the catalytic site, providing a basis for the unique position of the catalytic lysine. Mutagenesis of the chloride-binding site rendered the kinase less sensitive to inhibition of autophosphorylation by chloride, validating the binding site. Thus, these data suggest that WNK1 functions as a chloride sensor through direct binding of a regulatory chloride ion to the active site, which inhibits autophosphorylation.
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Affiliation(s)
- Alexander T Piala
- 1Department of Biophysics, The University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
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29
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Marunaka Y. Characteristics and Pharmacological Regulation of Epithelial Na+ Channel (ENaC) and Epithelial Na+ Transport. J Pharmacol Sci 2014. [DOI: 10.1254/jphs.14r01sr] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
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30
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Dagenais A, Tessier MC, Tatur S, Brochiero E, Grygorczyk R, Berthiaume Y. Hypotonic shock modulates Na(+) current via a Cl(-) and Ca(2+)/calmodulin dependent mechanism in alveolar epithelial cells. PLoS One 2013; 8:e74565. [PMID: 24019969 PMCID: PMC3760838 DOI: 10.1371/journal.pone.0074565] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Accepted: 08/05/2013] [Indexed: 12/02/2022] Open
Abstract
Alveolar epithelial cells are involved in Na+ absorption via the epithelial Na+ channel (ENaC), an important process for maintaining an appropriate volume of liquid lining the respiratory epithelium and for lung oedema clearance. Here, we investigated how a 20% hypotonic shock modulates the ionic current in these cells. Polarized alveolar epithelial cells isolated from rat lungs were cultured on permeant filters and their electrophysiological properties recorded. A 20% bilateral hypotonic shock induced an immediate, but transient 52% rise in total transepithelial current and a 67% increase in the amiloride-sensitive current mediated by ENaC. Amiloride pre-treatment decreased the current rise after hypotonic shock, showing that ENaC current is involved in this response. Since Cl- transport is modulated by hypotonic shock, its contribution to the basal and hypotonic-induced transepithelial current was also assessed. Apical NPPB, a broad Cl- channel inhibitor and basolateral DIOA a potassium chloride co-transporter (KCC) inhibitor reduced the total and ENaC currents, showing that transcellular Cl- transport plays a major role in that process. During hypotonic shock, a basolateral Cl- influx, partly inhibited by NPPB is essential for the hypotonic-induced current rise. Hypotonic shock promoted apical ATP secretion and increased intracellular Ca2+. While apyrase, an ATP scavenger, did not inhibit the hypotonic shock current response, W7 a calmodulin antagonist completely prevented the hypotonic current rise. These results indicate that a basolateral Cl- influx as well as Ca2+/calmodulin, but not ATP, are involved in the acute transepithelial current rise elicited by hypotonic shock.
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Affiliation(s)
- André Dagenais
- Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
- * E-mail:
| | | | - Sabina Tatur
- Centre de Recherche du CHUM (CRCHUM), Centre Hospitalier de l’Université de Montréal, Montreal, Quebec, Canada
| | - Emmanuelle Brochiero
- Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
- Centre de Recherche du CHUM (CRCHUM), Centre Hospitalier de l’Université de Montréal, Montreal, Quebec, Canada
| | - Ryszard Grygorczyk
- Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
- Centre de Recherche du CHUM (CRCHUM), Centre Hospitalier de l’Université de Montréal, Montreal, Quebec, Canada
| | - Yves Berthiaume
- Institut de Recherches Cliniques de Montréal (IRCM), Montreal, Quebec, Canada
- Département de Médecine, Université de Montréal, Montreal, Quebec, Canada
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31
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Baturina GS, Katkova LE, Ilyaskin AV, Solenov EI, Ivanova LN. Effect of hypoosmotic shock on the volume of renal collecting duct epithelial cells of brattleboro rats with hereditarily defective vasopressin synthesis. DOKL BIOCHEM BIOPHYS 2013; 449:102-4. [PMID: 23657658 DOI: 10.1134/s1607672913020130] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2012] [Indexed: 11/23/2022]
Affiliation(s)
- G S Baturina
- Institute of Cytology and Genetics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent'eva 10, Novosibirsk, 630090 Russia
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32
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Seale AP, Watanabe S, Breves JP, Lerner DT, Kaneko T, Gordon Grau E. Differential regulation of TRPV4 mRNA levels by acclimation salinity and extracellular osmolality in euryhaline tilapia. Gen Comp Endocrinol 2012; 178:123-30. [PMID: 22569116 DOI: 10.1016/j.ygcen.2012.04.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2012] [Revised: 04/20/2012] [Accepted: 04/23/2012] [Indexed: 11/26/2022]
Abstract
Prolactin (PRL) cells of the euryhaline Mozambique tilapia, Oreochromis mossambicus, are osmoreceptors. Hyposmotically-induced PRL release is mediated by the inward movement of extracellular Ca(2+) through a stretch-activated Ca(2+) channel, which has been recently identified as the transient receptor potential vanilloid 4 (TRPV4). In the present study, changes in plasma PRL, as well as PRL and TRPV4 mRNA expression from the rostral pars distalis (RPD), were measured in fish transferred from seawater (SW) to fresh water (FW) and in fish transferred from FW to SW. The in vitro effects of osmolality on PRL release and on PRL and TRPV4 mRNA expression in dispersed PRL cells were compared between fish adapted to SW and FW. Both the release and expression of PRL fell when fish were transferred to SW and rose when fish were transferred to FW. By contrast, TRPV4 expression increased by 48h after fish were transferred from FW to SW and declined as early as 6h after transfer from SW to FW. A similar pattern was observed in vitro where TRPV4 expression responded positively to an increase in medium osmolality while PRL expression declined. Incubation with the Ca(2+) ionophore, A23187, and the phosphodiesterase inhibitor, IBMX, stimulated PRL release. While both IBMX and A23187 inhibited TRPV4 expression, only A23187 reduced PRL expression. Together, these findings indicate that the expression of TRPV4 mRNA is osmosensitive, increasing as extracellular osmolality rises. Furthermore, these data suggest that TRPV4 expression may be regulated through the same second messenger pathways involved in hyposmotically-induced PRL release.
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Affiliation(s)
- Andre P Seale
- Hawaii Institute of Marine Biology, University of Hawaii, Kaneohe, HI 96744, USA.
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33
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Cesetti T, Fila T, Obernier K, Bengtson CP, Li Y, Mandl C, Hölzl-Wenig G, Ciccolini F. GABAA receptor signaling induces osmotic swelling and cell cycle activation of neonatal prominin+ precursors. Stem Cells 2011; 29:307-19. [PMID: 21732488 DOI: 10.1002/stem.573] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Signal-regulated changes in cell size affect cell division and survival and therefore are central to tissue morphogenesis and homeostasis. In this respect, GABA receptors (GABA(A)Rs) are of particular interest because allowing anions flow across the cell membrane modulates the osmolyte flux and the cell volume. Therefore, we have here investigated the hypothesis that GABA may regulate neural stem cell proliferation by inducing cell size changes. We found that, besides neuroblasts, also neural precursors in the neonatal murine subependymal zone sense GABA via GABA(A) Rs. However, unlike in neuroblasts, where it induced depolarization-mediated [Ca(2+)](i) increase, GABA(A) Rs activation in precursors caused hyperpolarization. This resulted in osmotic swelling and increased surface expression of epidermal growth factor receptors (EGFRs). Furthermore, activation of GABA(A) Rs signaling in vitro in the presence of EGF modified the expression of the cell cycle regulators, phosphatase and tensin homolog and cyclin D1, increasing the pool of cycling precursors without modifying cell cycle length. A similar effect was observed on treatment with diazepam. We also demonstrate that GABA and diazepam responsive precursors represent prominin(+) stem cells. Finally, we show that as in in vitro also in in vivo a short administration of diazepam promotes EGFR expression in prominin(+) stem cells causing activation and cell cycle entry. Thus, our data indicate that endogenous GABA is a part of a regulatory mechanism of size and cell cycle entry of neonatal stem cells. Our results also have potential implications for the therapeutic practices that involve exposure to GABA(A) Rs modulators during neurodevelopment.
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Affiliation(s)
- Tiziana Cesetti
- Department of Neurobiology, Interdisciplinary Center for Neurosciences (IZN), University of Heidelberg, Heidelberg, Germany
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34
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Rodighiero S, Bottà G, Bazzini C, Meyer G. Pendrin overexpression affects cell volume recovery, intracellular pH and chloride concentration after hypotonicity-induced cell swelling. Cell Physiol Biochem 2011; 28:559-70. [PMID: 22116371 DOI: 10.1159/000335120] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/04/2011] [Indexed: 11/19/2022] Open
Abstract
The pendrin (SLC26A4 or PDS) gene is responsible, when mutated, for the Pendred syndrome, a recessive disorder characterized by sensorineural hearing loss often accompanied by thyroid dysfunctions. Pendrin protein is an anion exchanger and we focused on a still unexplored function that it might play in view of its importance in the inner ear: Cl(-) fluxes regulation during cellular volume control. We challenged HEK-293 Phoenix cells over-expressing wild type pendrin (PDS HEK cells) together with the EYFP (Enhanced Yellow Fluorescent Protein) or over-expressing the EYFP alone (control HEK cells) with hypo-osmolar solutions. Taking advantage of the confocal optical sectioning we measured the cell volume. In addition, we determined the intracellular pH and chloride concentration with fluorescent probes (EYFP and seminaphthorhodafluor-5F, SNARF-5F). Consequently, we could estimate simultaneously Cl(-) fluxes, cellular volume and intracellular pH variations. Cl(-) movements markedly differed between PDS and control HEK cells upon hypotonic shock and are accompanied by an attenuation of the swelling induced pH drop in PDS HEK cells. The contemporary measurements of the three variables not yet reported in living cells, allowed to assess a possible influence of pendrin upregulation in volume homeostasis and evidenced its participation to Cl(-) fluxes.
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Regulation of epithelial sodium transport via epithelial Na+ channel. J Biomed Biotechnol 2011; 2011:978196. [PMID: 22028593 PMCID: PMC3196915 DOI: 10.1155/2011/978196] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2011] [Revised: 07/09/2011] [Accepted: 08/03/2011] [Indexed: 12/02/2022] Open
Abstract
Renal epithelial Na+ transport plays an important role in homeostasis of our body fluid content and blood pressure. Further, the Na+ transport in alveolar epithelial cells essentially controls the amount of alveolar fluid that should be kept at an appropriate level for normal gas exchange. The epithelial Na+ transport is generally mediated through two steps: (1) the entry step of Na+ via epithelial Na+ channel (ENaC) at the apical membrane and (2) the extrusion step of Na+ via the Na+, K+-ATPase at the basolateral membrane. In general, the Na+ entry via ENaC is the rate-limiting step. Therefore, the regulation of ENaC plays an essential role in control of blood pressure and normal gas exchange. In this paper, we discuss two major factors in ENaC regulation: (1) activity of individual ENaC and (2) number of ENaC located at the apical membrane.
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Steier R, Aradi M, Pál J, Bukovics P, Perlaki G, Orsi G, Janszky J, Schwarcz A, Sulyok E, Dóczi T. The influence of benzamil hydrochloride on the evolution of hyponatremic brain edema as assessed by in vivo MRI study in rats. Acta Neurochir (Wien) 2011; 153:2091-7; discussion 2097. [PMID: 21445679 DOI: 10.1007/s00701-011-0996-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Accepted: 03/09/2011] [Indexed: 11/29/2022]
Abstract
OBJECTIVE The present study was undertaken to reveal the influence of intracerebroventricular (ICV) benzamil on the dynamics of brain water accumulation in hyponatremic rats. Parameters of brain water homeostasis were continuously monitored, using in vivo magnetic resonance imaging (MRI) methods. The results were compared with those obtained in a previous study by tissue desiccation. METHODS A 3-T MRI instrument was applied to perform serial diffusion-weighted imaging to measure the apparent diffusion coefficient (ADC) and MR spectroscopy to determine water signal. A decrease of ADC is thought to represent an increase of intracellular water, whereas water signal is used to quantify brain water content. Five groups of male Wistar rats were studied as follows: normonatremic, native animals (group NN, n = 7), hyponatremic animals (group HN, n = 8), hyponatremic animals treated with ICV benzamil (group HNB, n = 8), hyponatremic animals treated with ICV saline (group HNS, n = 5) and normonatremic animals treated with ICV benzamil (group NNB, n = 5). Hyponatremia was induced by intraperitoneal administration of 140 mmol/l dextrose solution in a dose of 20% of body weight. Benzamil hydrochloride (4 μg) was injected ICV to the treated animals. RESULTS During the course of hyponatemia, ADC declined steadily from the baseline (100%) to reach a minimum of 92.32 ± 3.20% at 90 min (p < 0.0005). This process was associated with an increase in water signal to a maximum of 5.95 ± 2.62% at 100 min (p < 0.0005). After pretreatment with benzamil, no consistent changes occurred either in ADC or in water signal. CONCLUSIONS These findings suggest that sodium channel blockade with ICV benzamil has an immediate protective effect against the development of hyponatremic brain edema. Sodium channels, therefore, appear to be intimately involved in the initiation and progression of brain water accumulation in severe hyponatremia.
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Affiliation(s)
- Roy Steier
- Department of Neurosurgery, Faculty of Medicine, University of Pécs, Rét Street 2, 7623, Pécs, Hungary.
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Shiozaki A, Otsuji E, Marunaka Y. Intracellular chloride regulates the G 1/S cell cycle progression in gastric cancer cells. World J Gastrointest Oncol 2011; 3:119-22. [PMID: 22007274 PMCID: PMC3192220 DOI: 10.4251/wjgo.v3.i8.119] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Revised: 07/25/2011] [Accepted: 08/01/2011] [Indexed: 02/05/2023] Open
Abstract
Recent studies show that ion channels/transporters play important roles in fundamental cellular functions. Several reports indicating the important roles of Cl- channels/transporters on cell proliferation suggest that the intracellular chloride concentration ([Cl-]i) regulated by them would be one of critical messengers. We investigated whether the [Cl-]i controls cell proliferation and cell cycle progression in human gastric cancer cells. Our studies indicated that furosemide, a blocker of Na+/K+/2Cl- cotransporter (NKCC), diminished cell growth by delaying the G1-S phase progression in gastric cancer cells with high expression and activity of NKCC. Furthermore, we found that the culture in the low Cl- medium (replacement of Cl- by NO3-) decreased the [Cl-]i and inhibited cell growth of gastric cancer cells and that this inhibition of cell growth was due to cell cycle arrest at the G0/G1 phase caused by diminution of CDK2 and phosphorylated Rb. The culture of cells in the low Cl- medium significantly increased expressions of p21 mRNA and protein. In addition, the low Cl- medium induced phosphorylation of mitogen activated protein kinases (MAPKs). Treatment with an inhibitor of p38 or JNK significantly suppressed p21 upregulation caused by culture in a low Cl- medium and rescued gastric cancer cells from the low Cl--induced G1 cell cycle arrest. These findings revealed that the [Cl-]i affects the cell proliferation via activation of MAPKs through upregulation of p21 in gastric cancer cells. Our results suggest that the [Cl-]i regulates important cellular functions in gastric cancer cells, leading to the development of novel therapeutic strategies.
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Affiliation(s)
- Atsushi Shiozaki
- Atsushi Shiozaki, Eigo Otsuji, Division of Digestive Surgery, Department of Surgery, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Taruno A, Marunaka Y. Analysis of blocker-labeled channels reveals the dependence of recycling rates of ENaC on the total amount of recycled channels. Cell Physiol Biochem 2011; 26:925-34. [PMID: 21220923 DOI: 10.1159/000324001] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/15/2010] [Indexed: 11/19/2022] Open
Abstract
Trafficking is one of the primary mechanisms of epithelial Na(+) channel (ENaC) regulation. Although it is known that ENaCs are recycled between the apical membrane and the intracellular channel pool, it has been difficult to investigate the recycling of ENaCs; especially endogenously expressed ENaCs. The aim of the present study is to investigate if the recycling rates of ENaCs depend on the total amount of recycled ENaCs. To accomplish this point, we established a novel method to estimate the total amount of recycled ENaCs and the ENaC recycling rates by using a specific blocker (benzamil) of ENaC with a high-affinity for functional label of the channels in recycling. Applying this method, we studied if a decrease in the total amount of ENaCs caused by brefeldin A (5 μg/mL, 1 h) affects respectively the rates of insertion and endocytosis of ENaCs to and from the apical membrane in monolayers of renal epithelial A6 cells. Our observations indicate that: 1) both insertion and endocytosis rates of ENaC increase when the total amount of ENaCs decreases, 2) the increase in the insertion rate is larger than that in the endocytosis rate, and 3) this larger increase in the insertion rate than the endocytosis rate caused by the decrease in the total amount of ENaCs plays an important role in preventing Na(+) transport from drastically diminishing due to a decrease in the total amount of ENaCs. The newly established analysis of blocker-labeled ENaCs in the present study provides a useful tool to investigate the recycling of endogenously expressed ENaCs.
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Affiliation(s)
- Akiyuki Taruno
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Green Fluorescent Protein-Based Chloride Ion Sensors for In Vivo Imaging. FLUORESCENT PROTEINS II 2011. [DOI: 10.1007/4243_2011_27] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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Ohsawa R, Miyazaki H, Niisato N, Shiozaki A, Iwasaki Y, Otsuji E, Marunaka Y. Intracellular chloride regulates cell proliferation through the activation of stress-activated protein kinases in MKN28 human gastric cancer cells. J Cell Physiol 2010; 223:764-70. [PMID: 20205250 DOI: 10.1002/jcp.22088] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Recently, we reported that reduction of intracellular Cl(-) concentration ([Cl(-)](i)) inhibited proliferation of MKN28 gastric cancer cells by diminishing the transition rate from G(1) to S cell-cycle phase through upregulation of p21, cyclin-dependent kinase inhibitor, in a p53-independent manner. However, it is still unknown how intracellular Cl(-) regulates p21 expression level. In this study, we demonstrate that mitogen-activated protein kinases (MAPKs) are involved in the p21 upregulation and cell-cycle arrest induced by reduction of [Cl(-)](i). Culture of MKN28 cells in a low Cl(-) medium significantly induced phosphorylation (activation) of MAPKs (ERK, p38, and JNK) and G(1)/S cell-cycle arrest. To clarify the involvement of MAPKs in p21 upregulation and cell growth inhibition in the low Cl(-) medium, we studied effects of specific MAPKs inhibitors on p21 upregulation and G(1)/S cell-cycle arrest in MKN28 cells. Treatment with an inhibitor of p38 or JNK significantly suppressed p21 upregulation caused by culture in a low Cl(-) medium and rescued MKN28 cells from the low Cl(-)-induced G(1) cell-cycle arrest, whereas treatment with an ERK inhibitor had no significant effect on p21 expression or the growth of MKN28 cells in the low Cl(-) medium. These results strongly suggest that the intracellular Cl(-) affects the cell proliferation via activation of p38 and/or JNK cascades through upregulation of the cyclin-dependent kinase inhibitor (p21) in a p53-independent manner in MKN28 cells.
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Affiliation(s)
- Rumi Ohsawa
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Bregestovski P, Waseem T, Mukhtarov M. Genetically encoded optical sensors for monitoring of intracellular chloride and chloride-selective channel activity. Front Mol Neurosci 2009; 2:15. [PMID: 20057911 PMCID: PMC2802328 DOI: 10.3389/neuro.02.015.2009] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2009] [Accepted: 08/28/2009] [Indexed: 12/31/2022] Open
Abstract
This review briefly discusses the main approaches for monitoring chloride (Cl−), the most abundant physiological anion. Noninvasive monitoring of intracellular Cl− ([Cl−]i) is a challenging task owing to two main difficulties: (i) the low transmembrane ratio for Cl−, approximately 10:1; and (ii) the small driving force for Cl−, as the Cl− reversal potential (ECl) is usually close to the resting potential of the cells. Thus, for reliable monitoring of intracellular Cl−, one has to use highly sensitive probes. From several methods for intracellular Cl− analysis, genetically encoded chloride indicators represent the most promising tools. Recent achievements in the development of genetically encoded chloride probes are based on the fact that yellow fluorescent protein (YFP) exhibits Cl−-sensitivity. YFP-based probes have been successfully used for quantitative analysis of Cl− transport in different cells and for high-throughput screening of modulators of Cl−-selective channels. Development of a ratiometric genetically encoded probe, Clomeleon, has provided a tool for noninvasive estimation of intracellular Cl− concentrations. While the sensitivity of this protein to Cl− is low (EC50 about 160 mM), it has been successfully used for monitoring intracellular Cl− in different cell types. Recently a CFP–YFP-based probe with a relatively high sensitivity to Cl− (EC50 about 30 mM) has been developed. This construct, termed Cl-Sensor, allows ratiometric monitoring using the fluorescence excitation ratio. Of particular interest are genetically encoded probes for monitoring of ion channel distribution and activity. A new molecular probe has been constructed by introducing into the cytoplasmic domain of the Cl−-selective glycine receptor (GlyR) channel the CFP–YFP-based Cl-Sensor. This construct, termed BioSensor-GlyR, has been successfully expressed in cell lines. The new genetically encoded chloride probes offer means of screening pharmacological agents, analysis of Cl− homeostasis and functions of Cl−-selective channels under different physiological and pathological conditions.
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Viengchareun S, Kamenicky P, Teixeira M, Butlen D, Meduri G, Blanchard-Gutton N, Kurschat C, Lanel A, Martinerie L, Sztal-Mazer S, Blot-Chabaud M, Ferrary E, Cherradi N, Lombès M. Osmotic stress regulates mineralocorticoid receptor expression in a novel aldosterone-sensitive cortical collecting duct cell line. Mol Endocrinol 2009; 23:1948-62. [PMID: 19846540 DOI: 10.1210/me.2009-0095] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Aldosterone effects are mediated by the mineralocorticoid receptor (MR), a transcription factor highly expressed in the distal nephron. Given that MR expression level constitutes a key element controlling hormone responsiveness, there is much interest in elucidating the molecular mechanisms governing MR expression. To investigate whether hyper- or hypotonicity could affect MR abundance, we established by targeted oncogenesis a novel immortalized cortical collecting duct (CCD) cell line and examined the impact of osmotic stress on MR expression. KC3AC1 cells form domes, exhibit a high transepithelial resistance, express 11beta-hydroxysteroid dehydrogenase 2 and functional endogenous MR, which mediates aldosterone-stimulated Na(+) reabsorption through the epithelial sodium channel activation. MR expression is tightly regulated by osmotic stress. Hypertonic conditions induce expression of tonicity-responsive enhancer binding protein, an osmoregulatory transcription factor capable of binding tonicity-responsive enhancer response elements located in MR regulatory sequences. Surprisingly, hypertonicity leads to a severe reduction in MR transcript and protein levels. This is accompanied by a concomitant tonicity-induced expression of Tis11b, a mRNA-destabilizing protein that, by binding to the AU-rich sequences of the 3'-untranslated region of MR mRNA, may favor hypertonicity-dependent degradation of labile MR transcripts. In sharp contrast, hypotonicity causes a strong increase in MR transcript and protein levels. Collectively, we demonstrate for the first time that optimal adaptation of CCD cells to changes in extracellular fluid composition is accompanied by drastic modification in MR abundance via transcriptional and posttranscriptional mechanisms. Osmotic stress-regulated MR expression may represent an important molecular determinant for cell-specific MR action, most notably in renal failure, hypertension, or mineralocorticoid resistance.
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Yamada T, Niisato N, Marunaka Y. Effects of extracellular chloride ion on epithelial sodium channel (ENaC) in arginine vasotocin (AVT)-stimulated renal epithelial cells. ACTA ACUST UNITED AC 2009; 30:193-8. [PMID: 19574722 DOI: 10.2220/biomedres.30.193] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The epithelial Na(+) channel (ENaC) contributes to control of blood pressure by reabsorbing Na(+) in the cortical collecting duct of the kidney. The luminal Cl(-) concentration in the duct varies under physiological conditions. As the body Na(+) content is lower, the luminal Cl(-) concentration in the duct becomes lower. Thus, we hypothesized that the extracellular Cl(-) elevates ENaC activity in AVT-stimulated renal epithelial A6 cells (a model cell line of the cortical collecting duct) leading to recovery from a low body Na(+) content. To clarify this point, we studied effects of extracellular Cl(-) concentration on ENaC activity using cell-attached patch clamp technique. We found that ENaC had a single-channel conductance of 4.6 +/- 0.1 pS (mean +/- SE) and channel activity (open probability, Po) of 0.30 +/- 0.02 at a pipette potential of 60 mV. Lowering pipette Cl(-) concentration diminished Po to 0.23 +/- 0.02 associated with a significant decrease in open time from 0.78 +/- 0.03 to 0.61 +/- 0.02 s with no significant change in closed time, and shifted the current-voltage relationship leftward. These results suggest that the extracellular Cl(-) regulates the ENaC-mediated Na(+) reabsorption by affecting ENaC properties in AVT-stimulated renal epithelial cells.
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Affiliation(s)
- Toshiki Yamada
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto, Japan
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Tokuda S, Niisato N, Nagai T, Taruno A, Nakajima KI, Miyazaki H, Yamada T, Hosogi S, Ohta M, Nishio K, Iwasaki Y, Marunaka Y. Regulation of paracellular Na+ and Cl(-) conductances by hydrostatic pressure. Cell Biol Int 2009; 33:949-56. [PMID: 19524694 DOI: 10.1016/j.cellbi.2009.06.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 04/24/2009] [Accepted: 06/03/2009] [Indexed: 11/30/2022]
Abstract
The effect of hydrostatic pressure on the paracellular ion conductance (Gp) composed of the Na(+) conductance (G(Na)) and the Cl(-) conductance (G(Cl)) has been Investigated. Gp, G(Na) and G(Cl) were time-dependently increased after applying an osmotic gradient generated by NaCl with basolateral hypotonicity. Hydrostatic pressure (1-4cm H2O) applied from the basolateral side enhanced the osmotic gradient-induced increase in Gp, G(Na) and G(Cl) in a magnitude-dependent manner, while the hydrostatic pressure applied from the apical side diminished the osmotic gradient-induced increase in Gp, G(Na) and G(Cl). How the hydrostatic pressure influences Gp, G(Na) and G(Cl) under an isosmotic condition was also investigated. Gp, G(Na) and G(Cl) were stably constant under a condition with basolateral application of sucrose canceling the NaCl-generated osmotic gradient (an isotonic condition). Even under this stable condition, the basolaterally applied hydrostatic pressure drastically elevated Gp, G(Na) and G(Cl), while apically applied hydrostatic pressure had little effect on Gp, G(Na) or G(Cl). Taken together, these observations suggest that certain factors controlled by the basolateral osmolality and the basolaterally applied hydrostatic pressure mainly regulate the Gp, G(Na) and G(Cl).
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Affiliation(s)
- Shinsaku Tokuda
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Maki M, Miyazaki H, Niisato N, Morihara T, Marunaka Y, Kubo T. Blockers of K+/Cl- transporter/channels diminish proliferation of osteoblastic cells. Biomed Res 2009; 30:137-40. [DOI: 10.2220/biomedres.30.137] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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46
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Tokuda S, Niisato N, Nakajima KI, Marunaka Y. Regulation of the paracellular Na+ and Cl− conductances by the NaCl-generated osmotic gradient in a manner dependent on the direction of osmotic gradients. Biochem Biophys Res Commun 2008; 366:464-70. [DOI: 10.1016/j.bbrc.2007.11.167] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Accepted: 11/27/2007] [Indexed: 10/22/2022]
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Miyazaki H, Shiozaki A, Niisato N, Ohsawa R, Itoi H, Ueda Y, Otsuji E, Yamagishi H, Iwasaki Y, Nakano T, Nakahari T, Marunaka Y. Chloride ions control the G1/S cell-cycle checkpoint by regulating the expression of p21 through a p53-independent pathway in human gastric cancer cells. Biochem Biophys Res Commun 2007; 366:506-12. [PMID: 18067855 DOI: 10.1016/j.bbrc.2007.11.144] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Accepted: 11/29/2007] [Indexed: 12/11/2022]
Abstract
The aim of the present study is to investigate whether the chloride affects cell growth and cell-cycle progression of cancer cells. In human gastric cancer MKN28 cells, the culture in the Cl(-)-replaced medium (replacement of Cl(-) by NO(3)(-)) decreased the intracellular chloride concentration ([Cl(-)](i)) and inhibited cell growth. The inhibition of cell growth was due to cell-cycle arrest at the G(0)/G(1) phase caused by diminution of CDK2 and phosphorylated Rb. The culture of cells in the Cl(-)-replaced medium significantly increased expressions of p21 mRNA and protein without any effects on p53. These observations indicate that chloride ions play important roles in cell-cycle progression by regulating the expression of p21 through a p53-independent pathway in human gastric cancer cells, leading to a novel, unique therapeutic strategy for gastric cancer treatment via control of [Cl(-)](i).
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Affiliation(s)
- Hiroaki Miyazaki
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Maki M, Miyazaki H, Nakajima KI, Yamane J, Niisato N, Morihara T, Kubo T, Marunaka Y. Chloride-dependent acceleration of cell cycle via modulation of Rb and cdc2 in osteoblastic cells. Biochem Biophys Res Commun 2007; 361:1038-43. [PMID: 17679140 DOI: 10.1016/j.bbrc.2007.07.131] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2007] [Accepted: 07/24/2007] [Indexed: 01/13/2023]
Abstract
In the present study, we investigated if Cl(-) regulates the proliferation of the MC3T3-E1 osteoblastic cells. The proliferation of MC3T3-E1 osteoblastic cells was diminished by lowering the extracellular Cl(-) concentration ([Cl(-)](o)) in the culture medium. The lowered in [Cl(-)](o) increased the periods of the G(0)/G(1) and the G(2)/M phases in cell cycle. We further studied the effects of [Cl(-)](o) on the key enzymes, Rb and cdc2, playing key roles in checking points of the G(0)/G(1) and the G(2)/M phases in cell cycle. The lowered in [Cl(-)](o) diminished the active forms of enzymes, Rb and cdc2. We further found that the action of lowered [Cl(-)](o) on the cell proliferation, the cell cycle, Rb and cdc2 was abolished by the presence of 2mM glutamine, but not by that of pyruvate as another Krebs cycle substrate. Taken together, these observations indicate here for the first time that Cl(-) modulates Rb and cdc2, enhancing the proliferation of the MC3T3-E1 osteoblastic cells.
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Affiliation(s)
- Masahiro Maki
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Niisato N, Taruno A, Marunaka Y. Aldosterone-induced modification of osmoregulated ENaC trafficking. Biochem Biophys Res Commun 2007; 361:162-8. [PMID: 17658480 DOI: 10.1016/j.bbrc.2007.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 07/03/2007] [Indexed: 11/25/2022]
Abstract
Aldosterone and osmotic stress are well known to regulate the epithelial Na(+) channel (ENaC)-mediated Na(+) transport in renal epithelial cells. However, we have no information on how aldosterone and osmotic stress interact on stimulation of ENaC-mediated Na(+) transport in renal epithelium. In the present report, we studied how application of aldosterone (1 microM for 1 day) modifies the action of hypotonic stress on the ENaC-mediated Na(+) transport in renal A6 epithelial cells by measuring the benzamil (a specific inhibitor for ENaC)-sensitive short-circuit current. The present study suggests that: (1) most ENaCs in cells without aldosterone treatment are translocated to Golgi apparatus, (2) major parts of aldosterone-generated ENaCs are located at the endoplasmic reticulum, (3) aldosterone diminishes the endocytosis rate of ENaCs from the apical membrane without any significant changes in the insertion rate of ENaCs into the apical membrane, and (4) application of sucrose after hypotonic stress stimulates the endocytosis of ENaCs, and elongates the functional life time of ENaCs by enhancing recycle of ENaCs into the endoplasmic reticulum in a retrograde manner.
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Affiliation(s)
- Naomi Niisato
- Department of Molecular Cell Physiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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Niisato N, Taruno A, Marunaka Y. Involvement of p38 MAPK in hypotonic stress-induced stimulation of beta- and gamma-ENaC expression in renal epithelium. Biochem Biophys Res Commun 2007; 358:819-24. [PMID: 17506993 DOI: 10.1016/j.bbrc.2007.04.192] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2007] [Accepted: 04/28/2007] [Indexed: 12/13/2022]
Abstract
We investigated a role of p38 MAPK in the regulation of transepithelial Na(+) reabsorption by chronic application (20-24h) of hypotonicity (hypotonic stress) in renal epithelial A6 cells. Pretreatment with a specific p38 MAPK inhibitor (SB202190) significantly reduced the chronic hypotonicity-stimulated transepithelial Na(+) reabsorption by diminishing the Na(+) entry through epithelial Na(+) channel (ENaC) in the apical membrane and the Na(+) extrusion via the Na(+)/K(+) ATPase (pump), although the rate limiting step was still the Na(+) entry step. We further examined whether the inhibitory effects of SB202190 on the transepithelial Na(+) reabsorption is caused through suppression of mRNA expression of ENaC participating in the transepithelial Na(+) reabsorption as the Na(+) entry pathway. The chronic hypotonicity increased the mRNA expression of alpha-, beta-, and gamma-subunits of ENaC. Moreover, we found that inhibition of p38 MAPK by SB202190 diminished the mRNA expression of beta- and gamma-ENaC but not alpha-ENaC. Based on these observations, it is suggested that the chronic hypotonicity stimulates the renal transepithelial Na(+) reabsorption by upregulating the mRNA expression of beta- and gamma-ENaC via a p38 MAPK-dependent pathway.
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Affiliation(s)
- Naomi Niisato
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
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