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Sanders KM. Spontaneous Electrical Activity and Rhythmicity in Gastrointestinal Smooth Muscles. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:3-46. [PMID: 31183821 PMCID: PMC7035145 DOI: 10.1007/978-981-13-5895-1_1] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The gastrointestinal (GI) tract has multifold tasks of ingesting, processing, and assimilating nutrients and disposing of wastes at appropriate times. These tasks are facilitated by several stereotypical motor patterns that build upon the intrinsic rhythmicity of the smooth muscles that generate phasic contractions in many regions of the gut. Phasic contractions result from a cyclical depolarization/repolarization cycle, known as electrical slow waves, which result from intrinsic pacemaker activity. Interstitial cells of Cajal (ICC) are electrically coupled to smooth muscle cells (SMCs) and generate and propagate pacemaker activity and slow waves. The mechanism of slow waves is dependent upon specialized conductances expressed by pacemaker ICC. The primary conductances responsible for slow waves in mice are Ano1, Ca2+-activated Cl- channels (CaCCs), and CaV3.2, T-type, voltage-dependent Ca2+ channels. Release of Ca2+ from intracellular stores in ICC appears to be the initiator of pacemaker depolarizations, activation of T-type current provides voltage-dependent Ca2+ entry into ICC, as slow waves propagate through ICC networks, and Ca2+-induced Ca2+ release and activation of Ano1 in ICC amplifies slow wave depolarizations. Slow waves conduct to coupled SMCs, and depolarization elicited by these events enhances the open-probability of L-type voltage-dependent Ca2+ channels, promotes Ca2+ entry, and initiates contraction. Phasic contractions timed by the occurrence of slow waves provide the basis for motility patterns such as gastric peristalsis and segmentation. This chapter discusses the properties of ICC and proposed mechanism of electrical rhythmicity in GI muscles.
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Affiliation(s)
- Kenton M Sanders
- Department of Physiology and Cell Biology, University of Nevada, Reno School of Medicine, Reno, NV, USA.
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52
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Brandt C, Seja P, Töllner K, Römermann K, Hampel P, Kalesse M, Kipper A, Feit PW, Lykke K, Toft-Bertelsen TL, Paavilainen P, Spoljaric I, Puskarjov M, MacAulay N, Kaila K, Löscher W. Bumepamine, a brain-permeant benzylamine derivative of bumetanide, does not inhibit NKCC1 but is more potent to enhance phenobarbital's anti-seizure efficacy. Neuropharmacology 2018; 143:186-204. [DOI: 10.1016/j.neuropharm.2018.09.025] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 08/30/2018] [Accepted: 09/16/2018] [Indexed: 01/01/2023]
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Molecular characterization of Na+/K+/2Cl− cotransporter 1 alpha from Trachinotus ovatus (Linnaeus, 1758) and its expression responses to acute salinity stress. Comp Biochem Physiol B Biochem Mol Biol 2018; 223:29-38. [DOI: 10.1016/j.cbpb.2018.05.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Revised: 05/22/2018] [Accepted: 05/23/2018] [Indexed: 11/23/2022]
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54
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McNeill JK, Walton JC, Albers HE. Functional Significance of the Excitatory Effects of GABA in the Suprachiasmatic Nucleus. J Biol Rhythms 2018; 33:376-387. [PMID: 29974800 DOI: 10.1177/0748730418782820] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Over 90% of neurons within the suprachiasmatic nucleus (SCN) express γ-aminobutyric acid (GABA). Although GABA is primarily an inhibitory neurotransmitter, in vitro studies suggest that the activation of GABAA receptors (GABAAR) elicits excitation in the adult SCN. The ratio of excitatory to inhibitory responses to GABA depends on the balance of chloride influx by Na+-K+-Cl- cotransporter 1 (NKCC1) and chloride efflux by K+-Cl- cotransporters (KCCs). Excitatory responses to GABA can be blocked by inhibition of the inward chloride cotransporter, NKCC1, with the loop diuretic bumetanide. Here we investigated the role of NKCC1 activity in phase shifting the circadian pacemaker in response to photic and nonphotic signals in male Syrian hamsters housed in constant darkness. In the early subjective night (CT 13.5), injection of bumetanide into the SCN reduced light-induced phase delays. However, during the late subjective night (CT 19), bumetanide administration did not alter light-induced phase advances. Injection of bumetanide during the subjective day (CT 6) did not alter the phase of free-running circadian rhythms but attenuated phase advances induced by injection of the GABAAR agonist muscimol into the SCN. These data support the hypothesis that the excitatory effects of endogenously released GABA contribute to the ability of light to induce phase delays, thereby contributing to the most important function of the circadian system, its entrainment with the day-night cycle. Further, the finding that bumetanide inhibits the phase-advancing effects of muscimol during the subjective day supports the hypothesis that the excitatory responses to GABA also contribute to the ability of nonphotic stimuli to phase shift the circadian pacemaker.
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Affiliation(s)
- John K McNeill
- Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA
| | - James C Walton
- Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA
| | - H Elliott Albers
- Neuroscience Institute and Center for Behavioral Neuroscience, Georgia State University, Atlanta, GA, USA
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Azosemide is more potent than bumetanide and various other loop diuretics to inhibit the sodium-potassium-chloride-cotransporter human variants hNKCC1A and hNKCC1B. Sci Rep 2018; 8:9877. [PMID: 29959396 PMCID: PMC6026185 DOI: 10.1038/s41598-018-27995-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 06/14/2018] [Indexed: 12/31/2022] Open
Abstract
The Na+–K+–2Cl− cotransporter NKCC1 plays a role in neuronal Cl− homeostasis secretion and represents a target for brain pathologies with altered NKCC1 function. Two main variants of NKCC1 have been identified: a full-length NKCC1 transcript (NKCC1A) and a shorter splice variant (NKCC1B) that is particularly enriched in the brain. The loop diuretic bumetanide is often used to inhibit NKCC1 in brain disorders, but only poorly crosses the blood-brain barrier. We determined the sensitivity of the two human NKCC1 splice variants to bumetanide and various other chemically diverse loop diuretics, using the Xenopus oocyte heterologous expression system. Azosemide was the most potent NKCC1 inhibitor (IC50s 0.246 µM for hNKCC1A and 0.197 µM for NKCC1B), being about 4-times more potent than bumetanide. Structurally, a carboxylic group as in bumetanide was not a prerequisite for potent NKCC1 inhibition, whereas loop diuretics without a sulfonamide group were less potent. None of the drugs tested were selective for hNKCC1B vs. hNKCC1A, indicating that loop diuretics are not a useful starting point to design NKCC1B-specific compounds. Azosemide was found to exert an unexpectedly potent inhibitory effect and as a non-acidic compound, it is more likely to cross the blood-brain barrier than bumetanide.
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56
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Zacchia M, Capolongo G, Rinaldi L, Capasso G. The importance of the thick ascending limb of Henle's loop in renal physiology and pathophysiology. Int J Nephrol Renovasc Dis 2018; 11:81-92. [PMID: 29497325 PMCID: PMC5818843 DOI: 10.2147/ijnrd.s154000] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The thick ascending limb (TAL) of Henle’s loop is a crucial segment for many tasks of the nephron. Indeed, the TAL is not only a mainstay for reabsorption of sodium (Na+), potassium (K+), and divalent cations such as calcium (Ca2+) and magnesium (Mg2+) from the luminal fluid, but also has an important role in urine concentration, overall acid–base homeostasis, and ammonia cycle. Transcellular Na+ transport along the TAL is a prerequisite for Na+, K+, Ca2+, Mg2+ homeostasis, and water reabsorption, the latter through its contribution in the generation of the cortico-medullar osmotic gradient. The role of this nephron site in acid–base balance, via bicarbonate reabsorption and acid secretion, is sometimes misunderstood by clinicians. This review describes in detail these functions, reporting in addition to the well-known molecular mechanisms, some novel findings from the current literature; moreover, the pathophysiology and the clinical relevance of primary or acquired conditions caused by TAL dysfunction are discussed. Knowing the physiology of the TAL is fundamental for clinicians, for a better understanding and management of rare and common conditions, such as tubulopathies, hypertension, and loop diuretics abuse.
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Affiliation(s)
- Miriam Zacchia
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
| | - Giovanna Capolongo
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
| | - Luca Rinaldi
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
| | - Giovambattista Capasso
- Division of Nephrology, Department of Cardio-Thoracic and Respiratory Sciences, Università della Campania "Luigi Vanvitelli", Naples, Italy
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57
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Teng F, Guo M, Liu F, Wang C, Dong J, Zhang L, Zou Y, Chen R, Sun K, Fu H, Fu Z, Guo W, Ding G. Treatment with an SLC12A1 antagonist inhibits tumorigenesis in a subset of hepatocellular carcinomas. Oncotarget 2018; 7:53571-53582. [PMID: 27447551 PMCID: PMC5288206 DOI: 10.18632/oncotarget.10670] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2015] [Accepted: 07/06/2016] [Indexed: 01/23/2023] Open
Abstract
A central aim in cancer research is to identify genes with altered expression patterns in tumor specimens and their potential role in tumorigenesis. Most types of tumors, including hepatocellular carcinoma (HCC), are heterogeneous in terms of genotype and phenotype. Thus, traditional analytical methods like the t-test fail to identify all oncogenes from expression profiles. In this study, we performed a meta-Cancer Outlier Profile Analysis (meta-COPA) across six microarray datasets for HCC from the GEO database. We found that gene SLC12A1 was overexpressed in the Hep3B cell line, compared with five other HCC cell lines and L02 cells. We also found that the upregulation of SLC12A1 was mediated by histone methylation within its promoter region, and that SLC12A1 is a positive regulator of the WNK1/ERK5 pathway. Consistent with in vitro results, treatment with the SLC12A1 antagonist Bumetanide delayed tumor formation and reduced Hep3B cell tumor size in mouse xenografts. In summary, our research reveals a novel subset of HCCs that are sensitive to SLC12A1 antagonist treatment, thereby offering a new strategy for precision HCC treatment.
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Affiliation(s)
- Fei Teng
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Meng Guo
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Fang Liu
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Ce Wang
- Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Jiayong Dong
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Lei Zhang
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - You Zou
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Rui Chen
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Keyan Sun
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Hong Fu
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Zhiren Fu
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Wenyuan Guo
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
| | - Guoshan Ding
- Department of Liver Surgery and Organ Transplantation, Changzheng Hospital, Second Military Medical University, Shanghai 200003, China
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58
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McDermott JR, Geng X, Jiang L, Gálvez-Peralta M, Chen F, Nebert DW, Liu Z. Zinc- and bicarbonate-dependent ZIP8 transporter mediates selenite uptake. Oncotarget 2018; 7:35327-40. [PMID: 27166256 PMCID: PMC5085232 DOI: 10.18632/oncotarget.9205] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2015] [Accepted: 04/11/2016] [Indexed: 12/26/2022] Open
Abstract
Selenite (HSeO3−) is a monovalent anion of the essential trace element and micronutrient selenium (Se). In therapeutic concentrations, HSeO3− has been studied for treating certain cancers, serious inflammatory disorders, and septic shock. Little is known, however, about HSeO3− uptake into mammalian cells; until now, no mammalian HSeO3− uptake transporter has been identified. The ubiquitous mammalian ZIP8 divalent cation transporter (encoded by the SLC39A8 gene) is bicarbonate-dependent, moving endogenous substrates (Zn2+, Mn2+, Fe2+ or Co2+) and nonessential metals such as Cd2+ into the cell. Herein we studied HSeO3− uptake in: human and mouse cell cultures, shRNA-knockdown experiments, Xenopus oocytes, wild-type mice and two transgenic mouse lines having genetically altered ZIP8 expression, and mouse erythrocytes ex vivo. In mammalian cell culture, excess Zn2+ levels and/or ZIP8 over-expression can be associated with diminished viability in selenite-treated cells. Intraperitoneal HSeO3− causes the largest ZIP8-dependent increases in intracellular Se content in liver, followed by kidney, heart, lung and spleen. In every model system studied, HSeO3− uptake is tightly associated with ZIP8 protein levels and sufficient Zn2+ and HCO3− concentrations, suggesting that the ZIP8-mediated electroneutral complex transported contains three ions: Zn2+/(HCO3−)(HSeO3−). Transporters having three different ions in their transport complex are not without precedent. Although there might be other HSeO3− influx transporters as yet undiscovered, data herein suggest that mammalian ZIP8 plays a major role in HSeO3− uptake.
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Affiliation(s)
- Joseph R McDermott
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Xiangrong Geng
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Lan Jiang
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
| | - Marina Gálvez-Peralta
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH 45267, USA
| | - Fei Chen
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI 48201, USA
| | - Daniel W Nebert
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, OH 45267, USA
| | - Zijuan Liu
- Department of Biological Sciences, Oakland University, Rochester, MI 48309, USA
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59
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Abstract
Cell dehydration is a distinguishing characteristic of sickle cell disease and an important contributor to disease pathophysiology. Due to the unique dependence of Hb S polymerization on cellular Hb S concentration, cell dehydration promotes polymerization and sickling. In double heterozygosis for Hb S and C (SC disease) dehydration is the determining factor in disease pathophysiology. Three major ion transport pathways are involved in sickle cell dehydration: the K-Cl cotransport (KCC), the Gardos channel (KCNN4) and Psickle, the polymerization induced membrane permeability, most likely mediated by the mechano-sensitive ion channel PIEZO1. Each of these pathways exhibit unique characteristics in regulation by oxygen tension, intracellular and extracellular environment, and functional expression in reticulocytes and mature red cells. The unique dependence of K-Cl cotransport on intracellular Mg and the abnormal reduction of erythrocyte Mg content in SS and SC cells had led to clinical studies assessing the effect of oral Mg supplementation. Inhibition of Gardos channel by clotrimazole and senicapoc has led to Phase 1,2,3 trials in patients with sickle cell disease. While none of these studies has resulted in the approval of a novel therapy for SS disease, they have highlighted the key role played by these pathways in disease pathophysiology.
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Affiliation(s)
- Carlo Brugnara
- Department of Laboratory Medicine, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
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60
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Potassium Regulation in Medaka (Oryzias latipes) Larvae Acclimated to Fresh Water: Passive Uptake and Active Secretion by the Skin Cells. Sci Rep 2017; 7:16215. [PMID: 29176723 PMCID: PMC5701230 DOI: 10.1038/s41598-017-16381-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 11/13/2017] [Indexed: 01/29/2023] Open
Abstract
Molecular mechanisms of Na+, Cl−, and Ca2+ regulation in ionocytes of fish have been well investigated. However, the regulatory mechanism of K+ in fishes has been largely unknown. In this study, we investigated the mechanism of K+ regulation in medaka larvae acclimated to fresh water. Using a scanning ion-selective electrode technique (SIET) to measure the K+ fluxes at skin cells, significant K+ effluxes were found at ionocytes; in contrast, significant K+ influxes were found at the boundaries between keratinocytes. High K+ water (HK) acclimation induced the K+ effluxes at ionocytes and suppressed the K+ influxes at keratinocytes. The K+ effluxes of ionocytes were suppressed by VU591, bumetanide and ouabain. The K+ influxes of keratinocytes were suppressed by TAP. In situ hybridization analysis showed that mRNA of ROMKa was expressed by ionocytes in the skin and gills of medaka larvae. Quantitative PCR showed that mRNA levels of ROMKa and NKCC1a in gills of adult medaka were upregulated after HK acclimation. This study suggests that medaka obtain K+ through a paracellular pathway between keratinocytes and extrude K+ through ionocytes; apical ROMKa and basolateral NKCC1a are involved in the K+ secretion by ionocytes.
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61
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Watabe T, Xu M, Watanabe M, Nabekura J, Higuchi T, Hori K, Sato MP, Nin F, Hibino H, Ogawa K, Masuda M, Tanaka KF. Time-controllable Nkcc1 knockdown replicates reversible hearing loss in postnatal mice. Sci Rep 2017; 7:13605. [PMID: 29051615 PMCID: PMC5648887 DOI: 10.1038/s41598-017-13997-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/04/2017] [Indexed: 11/08/2022] Open
Abstract
Identification of the causal effects of specific proteins on recurrent and partially reversible hearing loss has been difficult because of the lack of an animal model that provides reversible gene knockdown. We have developed the transgenic mouse line Actin-tTS::Nkcc1 tetO/tetO for manipulatable expression of the cochlear K+ circulation protein, NKCC1. Nkcc1 transcription was blocked by the binding of a tetracycline-dependent transcriptional silencer to the tetracycline operator sequences inserted upstream of the Nkcc1 translation initiation site. Administration of the tetracycline derivative doxycycline reversibly regulated Nkcc1 knockdown. Progeny from pregnant/lactating mothers fed doxycycline-free chow from embryonic day 0 showed strong suppression of Nkcc1 expression (~90% downregulation) and Nkcc1 null phenotypes at postnatal day 35 (P35). P35 transgenic mice from mothers fed doxycycline-free chow starting at P0 (delivery) showed weaker suppression of Nkcc1 expression (~70% downregulation) and less hearing loss with mild cochlear structural changes. Treatment of these mice at P35 with doxycycline for 2 weeks reactivated Nkcc1 transcription to control levels and improved hearing level at high frequency; i.e., these doxycycline-treated mice exhibited partially reversible hearing loss. Thus, development of the Actin-tTS::Nkcc1 tetO/tetO transgenic mouse line provides a mouse model for the study of variable hearing loss through reversible knockdown of Nkcc1.
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Affiliation(s)
- Takahisa Watabe
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Ming Xu
- Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu city, Shizuoka, 431-3192, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, 38 Nishigonaka Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Taiga Higuchi
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Karin Hori
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Mitsuo P Sato
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
- Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata, 950-2181, Japan
| | - Kaoru Ogawa
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masatsugu Masuda
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
- Department of Otolaryngology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo, 181-8611, Japan.
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
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62
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Moreno E, Gayosso JA, Montejano JR, Almaguer G, Vázquez N, Cruz C, Mercado A, Bobadilla NA, Gamba G, Sierra A, Ramírez V. Geraniin is a diuretic by inhibiting the Na +-K +-2Cl - cotransporter NKCC2. Am J Physiol Renal Physiol 2017; 314:F240-F250. [PMID: 29046296 DOI: 10.1152/ajprenal.00221.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Geranium seemannii Peyr is a perennial plant endemic to central Mexico that has been widely used for its diuretic effect, but the responsible compound of this effect is unknown as well as the mechanism by which the diuretic effect is achieved. Geraniin is one of the compounds isolated from this kind of geranium. This study was designed to determinate whether geraniin possesses diuretic activity and to elucidate the mechanism of action. Geraniin was extracted and purified from Geranium seemannii Peyr. Male Wistar rats were divided into four groups: 1) Control, 2) 75 mg/kg of geraniin, 3) 20 mg/kg of furosemide, and 4) 10 mg/kg of hydrochlorothiazide. Each treatment was administered by gavage every 24 h for 7 days. The urinary excretion of electrolytes and the fractional excretion of sodium (FENa) were determined. To uncover the molecular target of geraniin, Xenopus laevis oocytes were microinjected with cRNAs encoding the Na+-Cl- cotransporter (NCC) and the Na+-K+-2Cl- cotransporter NKCC2 to functionally express these cotransporters. Geraniin significantly increased diuresis, natriuresis, and calciuresis to a similar extent as was observed in the furosemide-treated rats. Consistent with the furosemide-like effect, in X. laevis oocytes, geraniin significantly reduced the activity of NKCC2, with no effect on NCC activity. In contrast to furosemide, the effect of geraniin on NKCC2 was irreversible, apparently due to its inhibitory effect on heat shock protein 90. Our observations suggest that geraniin could have a potential role in the treatment of hypertension or edematous states.
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Affiliation(s)
- Erika Moreno
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - Juan A Gayosso
- Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo Pachuca, Hidalgo, Mexico
| | - José R Montejano
- Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo Pachuca, Hidalgo, Mexico
| | - Georgina Almaguer
- Instituto de Ciencias de la Salud, Universidad Autónoma del Estado de Hidalgo Pachuca, Hidalgo, Mexico
| | - Norma Vázquez
- Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Cristino Cruz
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
| | - Adriana Mercado
- Department of Nephrology, Instituto Nacional de Cardiología Ignacio Chávez, Tlalpan, Mexico City, Mexico
| | - Norma A Bobadilla
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico.,Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico
| | - Gerardo Gamba
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico.,Molecular Physiology Unit, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Mexico City, Mexico.,Tecnológico de Monterrey, Escuela de Medicina y de Ciencias de la Salud, Monterrey, Nuevo León , México
| | - Alfredo Sierra
- Escuela Superior de Medicina, Instituto Politécnico Nacional , Mexico City, Mexico
| | - Victoria Ramírez
- Department of Nephrology and Mineral Metabolism, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Tlalpan, Mexico City, Mexico
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63
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Hasegawa K, Sasaki S, Sakamoto Y, Takano A, Takayama M, Higashi T, Sugimoto Y, Yasuda Y. Furosemide loading test in a case of homozygous solute carrier family 12, member 1 (SLC12A1) mutation (g.62382825G>A, p.Pro372Leu) in Japanese Black cattle. Anim Sci J 2017; 88:1459-1464. [DOI: 10.1111/asj.12789] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2016] [Accepted: 12/22/2016] [Indexed: 12/24/2022]
Affiliation(s)
- Kiyotoshi Hasegawa
- Shimane Prefecture Livestock Technology Center; Koshi, Izumo, Shimane Japan
| | - Shinji Sasaki
- Shirakawa Institute of Animal Genetics; Japan Livestock Technology Association; Odakura, Nishigo, Fukushima Japan
| | - Yoichi Sakamoto
- Shimane Prefecture Livestock Technology Center; Koshi, Izumo, Shimane Japan
| | - Akifumi Takano
- Shimane Prefecture Livestock Technology Center; Koshi, Izumo, Shimane Japan
| | - Megumi Takayama
- Shimane Prefecture Livestock Technology Center; Koshi, Izumo, Shimane Japan
| | - Tomoko Higashi
- Shimane Prefecture Livestock Division Livestock Hygiene Research Office; Jinzaioki, Izumo, Shimane Japan
| | - Yoshikazu Sugimoto
- Shirakawa Institute of Animal Genetics; Japan Livestock Technology Association; Odakura, Nishigo, Fukushima Japan
| | - Yasuaki Yasuda
- Shimane Prefecture Livestock Technology Center; Koshi, Izumo, Shimane Japan
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64
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Wongsaengsak S, Vidmar AP, Addala A, Kamil ES, Sequeira P, Fass B, Pitukcheewanont P. A novel SLC12A1 gene mutation associated with hyperparathyroidism, hypercalcemia, nephrogenic diabetes insipidus, and nephrocalcinosis in four patients. Bone 2017; 97:121-125. [PMID: 28095294 DOI: 10.1016/j.bone.2017.01.011] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 12/25/2022]
Abstract
Solute Carrier Family 12 member 1 (SLC12A1) gene encodes the sodium-potassium-chloride co-transporter (NKCC2) at the apical membrane of the thick ascending loop of Henle (TAL). Bartter's syndrome (BS) type I is a rare, autosomal recessive, renal tubular disorder associated with mutation of the SLC12A1 gene. Presenting features include: hypokalemic metabolic alkalosis, hypercalciuria and nephrocalcinosis. The many allelic variants reported present with a spectrum of phenotypes, biochemical abnormalities and clinical severities. However, to date, only two reports have described hyperparathyroidism and hypercalcemia in patients with SLC12A1 gene mutations. We describe 4 patients with 4 novel mutation variants in the SLC12A1 gene (c.735C>G, c.1137del, c.2498-2499del, and c.1833delT) presenting with variable degrees of hyperparathyroidism, hypercalcemia, hypokalemic metabolic alkalosis, nephrocalcinosis, and nephrogenic diabetes insipidus. The link between calcium and parathyroid hormone abnormalities in patients with SLC12A1 mutations is unclear; the cases described suggest an association between primary hyperparathyroidism and loss of function mutation of SLC12A1, which may result in an aberrant threshold of the calcium sensing receptor at the level of the kidney.
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Affiliation(s)
- Sariya Wongsaengsak
- Center for Endocrinology, Diabetes and Metabolism, Division of Endocrinology, Children's Hospital Los Angeles, Los Angeles, CA, United States
| | - Alaina P Vidmar
- Center for Endocrinology, Diabetes and Metabolism, Division of Endocrinology, Children's Hospital Los Angeles, Los Angeles, CA, United States
| | - Ananta Addala
- Pediatric Endocrinology, Los Angeles County and University Medical Center University of Southern California, Los Angeles, California, United States
| | - Elaine S Kamil
- Department of Pediatric Nephrology, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Paola Sequeira
- Pediatric Endocrinology, Los Angeles County and University Medical Center University of Southern California, Los Angeles, California, United States; Keck School of Medicine of University of Southern California, Los Angeles, CA, United States
| | - Benjamin Fass
- Pediatric Endocrinology, Kaiser Permanente Medical Center Los Angeles, Los Angeles, CA, United States
| | - Pisit Pitukcheewanont
- Center for Endocrinology, Diabetes and Metabolism, Division of Endocrinology, Children's Hospital Los Angeles, Los Angeles, CA, United States; Keck School of Medicine of University of Southern California, Los Angeles, CA, United States.
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65
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Jiang C, Kawabe H, Rotin D. The Ubiquitin Ligase Nedd4L Regulates the Na/K/2Cl Co-transporter NKCC1/SLC12A2 in the Colon. J Biol Chem 2017; 292:3137-3145. [PMID: 28087701 DOI: 10.1074/jbc.m116.770065] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 01/03/2017] [Indexed: 01/06/2023] Open
Abstract
The ubiquitin ligase Nedd4-like (Nedd4L, or Nedd4-2) binds to and regulates stability of the epithelial Na+ channel (ENaC) in salt-absorbing epithelia in the kidney, lung, and other tissues. Its role in the distal colon, which also absorbs salt and fluid and expresses ENaC, is unknown. Using a conditional knock-out approach to knock out Nedd4L in mice intestinal epithelium (Nedd4Lf/f ;Vil-CreERT2 ) we show here that Nedd4L depletion leads to a higher steady-state short circuit current (Isc) in mouse distal colon tissue relative to controls. This higher Isc was partially reduced by the addition of apical amiloride and strongly reduced by basolateral bumetanide as well as by depletion of basolateral Cl-, suggesting that Na+/K+/2Cl- (NKCC1/SLC12A2) co-transporter and ENaC are targets of Nedd4L in the colon. In accordance, NKCC1 (and γENaC) protein abundance in the colon of the Nedd4L knock-out animals was increased, indicating that Nedd4L normally suppresses these proteins. However, we did not observe co-immunoprecipitation between Nedd4L and NKCC1, suggesting that Nedd4L indirectly suppresses NKCC1 expression. Low salt diet resulted in a strong increase in β and γ (but not α) ENaC mRNA and protein expression and ENaC activity. Although salt restriction also increased NKCC1 protein and mRNA abundance, it did not lead to its elevated activity (Isc). These results identify NKCC1 as a novel target for Nedd4L-mediated down-regulation in vivo, which modulates ion and fluid transport in the distal colon together with ENaC.
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Affiliation(s)
- Chong Jiang
- Hospital for Sick Children and University of Toronto, Toronto, Ontario M5G 0A4, Canada
| | - Hiroshi Kawabe
- Department of Molecular Neurobiology, Max Planck Institute of Experimental Medicine, Hermann-Rein-Strasse 3D, 37075 Goettingen, Germany
| | - Daniela Rotin
- Hospital for Sick Children and University of Toronto, Toronto, Ontario M5G 0A4, Canada.
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66
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Singh R, Kursan S, Almiahoub MY, Almutairi MM, Garzón-Muvdi T, Alvarez-Leefmans FJ, Di Fulvio M. Plasma Membrane Targeting of Endogenous NKCC2 in COS7 Cells Bypasses Functional Golgi Cisternae and Complex N-Glycosylation. Front Cell Dev Biol 2017; 4:150. [PMID: 28101499 PMCID: PMC5209364 DOI: 10.3389/fcell.2016.00150] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 12/14/2016] [Indexed: 12/04/2022] Open
Abstract
Na+K+2Cl− co-transporters (NKCCs) effect the electroneutral movement of Na+-K+ and 2Cl− ions across the plasma membrane of vertebrate cells. There are two known NKCC isoforms, NKCC1 (Slc12a2) and NKCC2 (Slc12a1). NKCC1 is a ubiquitously expressed transporter involved in cell volume regulation, Cl− homeostasis and epithelial salt secretion, whereas NKCC2 is abundantly expressed in kidney epithelial cells of the thick ascending loop of Henle, where it plays key roles in NaCl reabsorption and electrolyte homeostasis. Although NKCC1 and NKCC2 co-transport the same ions with identical stoichiometry, NKCC1 actively co-transports water whereas NKCC2 does not. There is growing evidence showing that NKCC2 is expressed outside the kidney, but its function in extra-renal tissues remains unknown. The present study shows molecular and functional evidence of endogenous NKCC2 expression in COS7 cells, a widely used mammalian cell model. Endogenous NKCC2 is primarily found in recycling endosomes, Golgi cisternae, Golgi-derived vesicles, and to a lesser extent in the endoplasmic reticulum. Unlike NKCC1, NKCC2 is minimally hybrid/complex N-glycosylated under basal conditions and yet it is trafficked to the plasma membrane region of hyper-osmotically challenged cells through mechanisms that require minimal complex N-glycosylation or functional Golgi cisternae. Control COS7 cells exposed to slightly hyperosmotic (~6.7%) solutions for 16 h were not shrunken, suggesting that either one or both NKCC1 and NKCC2 may participate in cell volume recovery. However, NKCC2 targeted to the plasma membrane region or transient over-expression of NKCC2 failed to rescue NKCC1 in COS7 cells where NKCC1 had been silenced. Further, COS7 cells in which NKCC1, but not NKCC2, was silenced exhibited reduced cell size compared to control cells. Altogether, these results suggest that NKCC2 does not participate in cell volume recovery and therefore, NKCC1 and NKCC2 are functionally different Na+K+2Cl− co-transporters.
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Affiliation(s)
- Richa Singh
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University Dayton, OH, USA
| | - Shams Kursan
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University Dayton, OH, USA
| | - Mohamed Y Almiahoub
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University Dayton, OH, USA
| | - Mohammed M Almutairi
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University Dayton, OH, USA
| | - Tomás Garzón-Muvdi
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University Dayton, OH, USA
| | - Francisco J Alvarez-Leefmans
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University Dayton, OH, USA
| | - Mauricio Di Fulvio
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University Dayton, OH, USA
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67
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Xu BP, Tu DD, Yan MC, Shu MA, Shao QJ. Molecular characterization of a cDNA encoding Na+/K+/2Cl− cotransporter in the gill of mud crab (Scylla paramamosain) during the molt cycle: Implication of its function in osmoregulation. Comp Biochem Physiol A Mol Integr Physiol 2017; 203:115-125. [DOI: 10.1016/j.cbpa.2016.08.019] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2016] [Revised: 08/19/2016] [Accepted: 08/19/2016] [Indexed: 01/17/2023]
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68
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Zhu MH, Sung TS, Kurahashi M, O'Kane LE, O'Driscoll K, Koh SD, Sanders KM. Na+-K+-Cl- cotransporter (NKCC) maintains the chloride gradient to sustain pacemaker activity in interstitial cells of Cajal. Am J Physiol Gastrointest Liver Physiol 2016; 311:G1037-G1046. [PMID: 27742704 PMCID: PMC5206290 DOI: 10.1152/ajpgi.00277.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 10/11/2016] [Indexed: 01/31/2023]
Abstract
Interstitial cells of Cajal (ICC) generate electrical slow waves by coordinated openings of ANO1 channels, a Ca2+-activated Cl- (CaCC) conductance. Efflux of Cl- during slow waves must be significant, as there is high current density during slow-wave currents and slow waves are of sufficient magnitude to depolarize the syncytium of smooth muscle cells and PDGFRα+ cells to which they are electrically coupled. We investigated how the driving force for Cl- current is maintained in ICC. We found robust expression of Slc12a2 (which encodes an Na+-K+-Cl- cotransporter, NKCC1) and immunohistochemical confirmation that NKCC1 is expressed in ICC. With the use of the gramicidin permeabilized-patch technique, which is reported to not disturb [Cl-]i, the reversal potential for spontaneous transient inward currents (ESTICs) was -10.5 mV. This value corresponds to the peak of slow waves when they are recorded directly from ICC in situ. Inhibition of NKCC1 with bumetanide shifted ESTICs to more negative potentials within a few minutes and reduced pacemaker activity. Bumetanide had no direct effects on ANO1 or CaV3.2 channels expressed in HEK293 cells or L-type Ca2+ currents. Reducing extracellular Cl- to 10 mM shifted ESTICs to positive potentials as predicted by the Nernst equation. The relatively rapid shift in ESTICs when NKCC1 was blocked suggests that significant changes in the transmembrane Cl- gradient occur during the slow-wave cycle, possibly within microdomains formed between endoplasmic reticulum and the plasma membrane in ICC. Recovery of Cl- via NKCC1 might have additional consequences on shaping the waveforms of slow waves via Na+ entry into microdomains.
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Affiliation(s)
- Mei Hong Zhu
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Tae Sik Sung
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Masaaki Kurahashi
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Lauren E. O'Kane
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Kate O'Driscoll
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Sang Don Koh
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
| | - Kenton M. Sanders
- Department of Physiology and Cell Biology, University of Nevada School of Medicine, Reno, Nevada
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69
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Delpire E, Wolfe L, Flores B, Koumangoye R, Schornak CC, Omer S, Pusey B, Lau C, Markello T, Adams DR. A patient with multisystem dysfunction carries a truncation mutation in human SLC12A2, the gene encoding the Na-K-2Cl cotransporter, NKCC1. Cold Spring Harb Mol Case Stud 2016; 2:a001289. [PMID: 27900370 PMCID: PMC5111002 DOI: 10.1101/mcs.a001289] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 10/10/2016] [Indexed: 12/30/2022] Open
Abstract
This study describes a 13-yr-old girl with orthostatic intolerance, respiratory weakness, multiple endocrine abnormalities, pancreatic insufficiency, and multiorgan failure involving the gut and bladder. Exome sequencing revealed a de novo, loss-of-function allele in SLC12A2, the gene encoding the Na-K-2Cl cotransporter-1. The 11-bp deletion in exon 22 results in frameshift (p.Val1026Phefs*2) and truncation of the carboxy-terminal tail of the cotransporter. Preliminary studies in heterologous expression systems demonstrate that the mutation leads to a nonfunctional transporter, which is expressed and trafficked to the plasma membrane alongside wild-type NKCC1. The truncated protein, visible at higher molecular sizes, indicates either enhanced dimerization or misfolded aggregate. No significant dominant-negative effect was observed. K+ transport experiments performed in fibroblasts from the patient showed reduced total and NKCC1-mediated K+ influx. The absence of a bumetanide effect on K+ influx in patient fibroblasts only under hypertonic conditions suggests a deficit in NKCC1 regulation. We propose that disruption in NKCC1 function might affect sensory afferents and/or smooth muscle cells, as their functions depend on NKCC1 creating a Cl- gradient across the plasma membrane. This Cl- gradient allows the γ-aminobutyric acid (GABA) receptor or other Cl- channels to depolarize the membrane affecting processes such as neurotransmission or cell contraction. Under this hypothesis, disrupted sensory and smooth muscle function in a diverse set of tissues could explain the patient's phenotype.
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Affiliation(s)
- Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Lynne Wolfe
- Undiagnosed Diseases Program, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Bianca Flores
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Rainelli Koumangoye
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Cara C Schornak
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Salma Omer
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | - Barbara Pusey
- Undiagnosed Diseases Program, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Christopher Lau
- Undiagnosed Diseases Program, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Thomas Markello
- Undiagnosed Diseases Program, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - David R Adams
- Undiagnosed Diseases Program, National Institutes of Health, Bethesda, Maryland 20892, USA
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70
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Gorrieri G, Scudieri P, Caci E, Schiavon M, Tomati V, Sirci F, Napolitano F, Carrella D, Gianotti A, Musante I, Favia M, Casavola V, Guerra L, Rea F, Ravazzolo R, Di Bernardo D, Galietta LJV. Goblet Cell Hyperplasia Requires High Bicarbonate Transport To Support Mucin Release. Sci Rep 2016; 6:36016. [PMID: 27786259 PMCID: PMC5081536 DOI: 10.1038/srep36016] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 10/05/2016] [Indexed: 12/15/2022] Open
Abstract
Goblet cell hyperplasia, a feature of asthma and other respiratory diseases, is driven by the Th-2 cytokines IL-4 and IL-13. In human bronchial epithelial cells, we find that IL-4 induces the expression of many genes coding for ion channels and transporters, including TMEM16A, SLC26A4, SLC12A2, and ATP12A. At the functional level, we find that IL-4 enhances calcium- and cAMP-activated chloride/bicarbonate secretion, resulting in high bicarbonate concentration and alkaline pH in the fluid covering the apical surface of epithelia. Importantly, mucin release, elicited by purinergic stimulation, requires the presence of bicarbonate in the basolateral solution and is defective in cells derived from cystic fibrosis patients. In conclusion, our results suggest that Th-2 cytokines induce a profound change in expression and function in multiple ion channels and transporters that results in enhanced bicarbonate transport ability. This change is required as an important mechanism to favor release and clearance of mucus.
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Affiliation(s)
- Giulia Gorrieri
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | - Paolo Scudieri
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | - Emanuela Caci
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | - Marco Schiavon
- Department of Thoracic Surgery, University of Padova, Italy
| | - Valeria Tomati
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | - Francesco Sirci
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | | | - Diego Carrella
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Ambra Gianotti
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | - Ilaria Musante
- Telethon Institute of Genetics and Medicine, Pozzuoli, Italy
| | - Maria Favia
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Italy
| | - Valeria Casavola
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Italy
| | - Lorenzo Guerra
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, Italy
| | - Federico Rea
- Department of Thoracic Surgery, University of Padova, Italy
| | - Roberto Ravazzolo
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy.,DINOGMI, University of Genova, Italy
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71
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Marunaka Y, Marunaka R, Sun H, Yamamoto T, Kanamura N, Taruno A. Na + homeostasis by epithelial Na + channel (ENaC) and Na x channel (Na x): cooperation of ENaC and Na x. ANNALS OF TRANSLATIONAL MEDICINE 2016; 4:S11. [PMID: 27867979 DOI: 10.21037/atm.2016.10.42] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Yoshinori Marunaka
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan;; Department of Bio-Ionomics, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan;; Japan Institute for Food Education and Health, St. Agnes' University, Kyoto 602-8013, Japan
| | - Rie Marunaka
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan;; Department of Dental Medicine, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan
| | - Hongxin Sun
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan
| | - Toshiro Yamamoto
- Department of Dental Medicine, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan
| | - Narisato Kanamura
- Department of Dental Medicine, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan
| | - Akiyuki Taruno
- Department of Molecular Cell Physiology, Kyoto Prefectural University of Medicine Graduate School of Medical Science, Kyoto 602-8566, Japan
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72
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Lykke K, Töllner K, Feit PW, Erker T, MacAulay N, Löscher W. The search for NKCC1-selective drugs for the treatment of epilepsy: Structure-function relationship of bumetanide and various bumetanide derivatives in inhibiting the human cation-chloride cotransporter NKCC1A. Epilepsy Behav 2016; 59:42-9. [PMID: 27088517 DOI: 10.1016/j.yebeh.2016.03.021] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Revised: 03/11/2016] [Accepted: 03/12/2016] [Indexed: 11/30/2022]
Abstract
The Na(+)-K(+)-Cl(-) cotransporter NKCC1 plays a major role in the regulation of intraneuronal Cl(-) concentration. Abnormal functionality of NKCC1 has been implicated in several brain disorders, including epilepsy. Bumetanide is the only available selective NKCC1 inhibitor, but also inhibits NKCC2, which can cause severe adverse effects during treatment of brain disorders. A NKCC1-selective bumetanide derivative would therefore be a desirable option. In the present study, we used the Xenopus oocyte heterologous expression system to compare the effects of bumetanide and several derivatives on the two major human splice variants of NKCCs, hNKCC1A and hNKCC2A. The derivatives were selected from a series of ~5000 3-amino-5-sulfamoylbenzoic acid derivatives, covering a wide range of structural modifications and diuretic potencies. To our knowledge, such structure-function relationships have not been performed before for NKCC1. Half maximal inhibitory concentrations (IC50s) of bumetanide were 0.68 (hNKCC1A) and 4.0μM (hNKCC2A), respectively, indicating that this drug is 6-times more potent to inhibit hNKCC1A than hNKCC2A. Side chain substitutions in the bumetanide molecule variably affected the potency to inhibit hNKCC1A. This allowed defining the minimal structural requirements necessary for ligand interaction. Unexpectedly, only a few of the bumetanide derivatives examined were more potent than bumetanide to inhibit hNKCC1A, and most of them also inhibited hNKCC2A, with a highly significant correlation between IC50s for the two NKCC isoforms. These data indicate that the structural requirements for inhibition of NKCC1 and NKCC2 are similar, which complicates development of bumetanide-related compounds with high selectivity for NKCC1.
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Affiliation(s)
- Kasper Lykke
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany
| | - Peter W Feit
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany
| | - Thomas Erker
- Department of Medicinal Chemistry, University of Vienna, Vienna, Austria
| | - Nanna MacAulay
- Department of Neuroscience and Pharmacology, University of Copenhagen, Copenhagen, Denmark.
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine Hannover, Germany; Center for Systems Neuroscience, Hannover, Germany.
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73
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Ragel P, Ródenas R, García-Martín E, Andrés Z, Villalta I, Nieves-Cordones M, Rivero RM, Martínez V, Pardo JM, Quintero FJ, Rubio F. The CBL-Interacting Protein Kinase CIPK23 Regulates HAK5-Mediated High-Affinity K+ Uptake in Arabidopsis Roots. PLANT PHYSIOLOGY 2015; 169:2863-73. [PMID: 26474642 PMCID: PMC4677917 DOI: 10.1104/pp.15.01401] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2015] [Accepted: 10/16/2015] [Indexed: 05/18/2023]
Abstract
Plant growth and development requires efficient acquisition of essential elements. Potassium (K(+)) is an important macronutrient present in the soil solution at a wide range of concentrations. Regulation of the K(+) uptake systems in the roots is essential to secure K(+) supply. It has been shown in Arabidopsis (Arabidopsis thaliana) that when the external K(+) concentration is very low (<10 µm), K(+) nutrition depends exclusively on the high-affinity K(+) transporter5 (HAK5). Low-K(+)-induced transcriptional activation of the gene encoding HAK5 has been previously reported. Here, we show the posttranscriptional regulation of HAK5 transport activity by phosphorylation. Expression in a heterologous system showed that the Ca(2+) sensors calcineurin B-like (CBL1), CBL8, CBL9, and CBL10, together with CBL-interacting protein kinase23 (CIPK23), activated HAK5 in vivo. This activation produced an increase in the affinity and the Vmax of K(+) transport. In vitro experiments show that the N terminus of HAK5 is phosphorylated by CIPK23. This supports the idea that phosphorylation of HAK5 induces a conformational change that increases its affinity for K(+). Experiments of K(+) (Rb(+)) uptake and growth measurements in low-K(+) medium with Arabidopsis single mutants hak5, akt1, and cipk23, double mutants hak5 akt1, hak5 cipk23, and akt1 cipk23, and the triple mutant hak5 akt1 cipk23 confirmed the regulatory role of CIPK23 in planta.
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Affiliation(s)
- Paula Ragel
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Reyes Ródenas
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Elena García-Martín
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Zaida Andrés
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Irene Villalta
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Manuel Nieves-Cordones
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Rosa M Rivero
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Vicente Martínez
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Jose M Pardo
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Francisco J Quintero
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
| | - Francisco Rubio
- Departamento de Biotecnología Vegetal, Instituto de Recursos Naturales y Agrobiología, Consejo Superior de Investigaciones Científicas, Sevilla E-41012, Spain (P.R., E.G.-M., Z.A., I.V., J.M.P., F.J.Q.);Departamento de Nutrición Vegetal, Centro de Edafología y Biología Aplicada del Segura, Consejo Superior de Investigaciones Científicas, Campus de Espinardo, Murcia 30100, Spain (R.R., R.M.R., V.M., F.R.); andBiochimie et Physiologie Moléculaire des Plantes, Institut de Biologie Intégrative des Plantes, Unité Mixte de Recherche 5004 Centre National de la Recherche Scientifique/Unité Mixte de Recherche 0386 Institut National de la Recherche Agronomique/Montpellier SupAgro/Université Montpellier 2, 34060 Montpellier cedex 2, France (M.N.-C.)
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Targeted Gene Resequencing (Astrochip) to Explore the Tripartite Synapse in Autism-Epilepsy Phenotype with Macrocephaly. Neuromolecular Med 2015; 18:69-80. [PMID: 26537360 DOI: 10.1007/s12017-015-8378-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Accepted: 10/27/2015] [Indexed: 12/26/2022]
Abstract
The frequent co-occurrence of autism spectrum disorders (ASD) and epilepsy, or paroxysmal EEG abnormalities, defines a condition termed autism-epilepsy phenotype (AEP). This condition results, in some cases , from dysfunctions of glial inwardly rectifying potassium channels (Kir), which are mainly expressed in astrocytes where they mediate neuron-glia communication. Macrocephaly is also often comorbid with autism-epilepsy (autism-epilepsy phenotype with macrocephaly, MAEP), and it is tempting to hypothesize that shared pathogenic mechanisms might explain concurrence of these conditions. In the present study, we assessed whether protein pathways involved, along with Kir channels, in astrocyte-neuron interaction at the tripartite synapse play a role in the etiopathogenesis of MAEP. Using a targeted resequencing methodology, we investigated the coding regions of 35 genes in 61 patients and correlated genetic results with clinical features. Variants were subdivided into 12 classes and clustered into four groups. We detected rare or previously unknown predicted deleterious missense changes in GJA1, SLC12A2, SNTA1, EFNA3, CNTNAP2, EPHA4, and STXBP1 in seven patients and two high-frequency variants in DLG1 in six individuals. We also found that a group of variants (predicted deleterious and non-coding), segregating with the comorbid MAEP/AEP subgroups, belong to proteins specifically involved in glutamate transport and metabolism (namely, SLC17A6, GRM8, and GLUL), as well as in potassium conductance (KCNN3). This "endophenotype-oriented" study, performed using a targeted strategy, helped to further delineate part of the complex genetic background of ASD, particularly in the presence of coexisting macrocephaly and/or epilepsy/paroxysmal EEG, and suggests that use of stringent clinical clustering might be an approach worth adopting in order to unravel the complex genomic data in neurodevelopmental disorders.
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Lykke K, Töllner K, Römermann K, Feit PW, Erker T, MacAulay N, Löscher W. Structure-activity relationships of bumetanide derivatives: correlation between diuretic activity in dogs and inhibition of the human NKCC2A transporter. Br J Pharmacol 2015; 172:4469-4480. [PMID: 26101812 PMCID: PMC4562508 DOI: 10.1111/bph.13231] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Revised: 05/28/2015] [Accepted: 06/12/2015] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND AND PURPOSE The N-K-Cl cotransporters (NKCCs) mediate the coupled, electroneutral movement of Na+ , K+ and Cl- ions across cell membranes. There are two isoforms of this cation co-transporter, NKCC1 and NKCC2. NKCC2 is expressed primarily in the kidney and is the target of diuretics such as bumetanide. Bumetanide was discovered by screening ∼5000 3-amino-5-sulfamoylbenzoic acid derivatives, long before NKCC2 was identified in the kidney. Therefore, structure-activity studies on effects of bumetanide derivatives on NKCC2 are not available. EXPERIMENTAL APPROACH In this study, the effect of a series of diuretically active bumetanide derivatives was investigated on human NKCC2 variant A (hNKCC2A) expressed in Xenopus laevis oocytes. KEY RESULTS Bumetanide blocked hNKCC2A transport with an IC50 of 4 μM. There was good correlation between the diuretic potency of bumetanide and its derivatives in dogs and their inhibition of hNKCC2A (r2 = 0.817; P < 0.01). Replacement of the carboxylic group of bumetanide by a non-ionic residue, for example, an anilinomethyl group, decreased inhibition of hNKCC2A, indicating that an acidic group was required for transporter inhibition. Exchange of the phenoxy group of bumetanide for a 4-chloroanilino group or the sulfamoyl group by a methylsulfonyl group resulted in compounds with higher potency to inhibit hNKCC2A than bumetanide. CONCLUSIONS AND IMPLICATIONS The X. laevis oocyte expression system used in these experiments allowed analysis of the structural requirements that determine relative potency of loop diuretics on human NKCC2 splice variants, and may lead to the discovery of novel high-ceiling diuretics.
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Affiliation(s)
- Kasper Lykke
- Department of Cellular and Molecular Medicine, University of CopenhagenCopenhagen, Denmark
| | - Kathrin Töllner
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine HannoverHannover, Germany
- Center for Systems NeuroscienceHannover, Germany
| | - Kerstin Römermann
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine HannoverHannover, Germany
- Center for Systems NeuroscienceHannover, Germany
| | - Peter W Feit
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine HannoverHannover, Germany
| | - Thomas Erker
- Department of Medicinal Chemistry, University of ViennaVienna, Austria
| | - Nanna MacAulay
- Department of Cellular and Molecular Medicine, University of CopenhagenCopenhagen, Denmark
| | - Wolfgang Löscher
- Department of Pharmacology, Toxicology, and Pharmacy, University of Veterinary Medicine HannoverHannover, Germany
- Center for Systems NeuroscienceHannover, Germany
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76
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Taylor CA, Juang YC, Earnest S, Sengupta S, Goldsmith EJ, Cobb MH. Domain-Swapping Switch Point in Ste20 Protein Kinase SPAK. Biochemistry 2015; 54:5063-71. [PMID: 26208601 PMCID: PMC5167558 DOI: 10.1021/acs.biochem.5b00593] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The related protein kinases SPAK and OSR1 regulate ion homeostasis in part by phosphorylating cation cotransporter family members. The structure of the kinase domain of OSR1 was determined in the unphosphorylated inactive form and, like some other Ste20 kinases, exhibited a domain-swapped activation loop. To further probe the role of domain swapping in SPAK and OSR1, we have determined the crystal structures of SPAK 63-403 at 3.1 Å and SPAK 63-390 T243D at 2.5 Å resolution. These structures encompass the kinase domain and different portions of the C-terminal tail, the longer without and the shorter with an activating T243D point mutation. The structure of the T243D protein reveals significant conformational differences relative to unphosphorylated SPAK and OSR1 but also has some features of an inactive kinase. Both structures are domain-swapped dimers. Sequences involved in domain swapping were identified and mutated to create a SPAK monomeric mutant with kinase activity, indicating that monomeric forms are active. The monomeric mutant is activated by WNK1 but has reduced activity toward its substrate NKCC2, suggesting regulatory roles for domain swapping. The structure of partially active SPAK T243D is consistent with a multistage activation process in which phosphorylation induces a SPAK conformation that requires further remodeling to build the active structure.
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Affiliation(s)
- Clinton A. Taylor
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Yu-Chi Juang
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Svetlana Earnest
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Samarpita Sengupta
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Elizabeth J. Goldsmith
- Department of Biophysics, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Melanie H. Cobb
- Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
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Kahle KT, Khanna AR, Alper SL, Adragna NC, Lauf PK, Sun D, Delpire E. K-Cl cotransporters, cell volume homeostasis, and neurological disease. Trends Mol Med 2015; 21:513-23. [PMID: 26142773 PMCID: PMC4834970 DOI: 10.1016/j.molmed.2015.05.008] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2015] [Revised: 05/10/2015] [Accepted: 05/29/2015] [Indexed: 11/24/2022]
Abstract
K(+)-Cl(-) cotransporters (KCCs) were originally characterized as regulators of red blood cell (RBC) volume. Since then, four distinct KCCs have been cloned, and their importance for volume regulation has been demonstrated in other cell types. Genetic models of certain KCCs, such as KCC3, and their inhibitory WNK-STE20/SPS1-related proline/alanine-rich kinase (SPAK) serine-threonine kinases, have demonstrated the evolutionary necessity of these molecules for nervous system cell volume regulation, structure, and function, and their involvement in neurological disease. The recent characterization of a swelling-activated dephosphorylation mechanism that potently stimulates the KCCs has pinpointed a potentially druggable switch of KCC activity. An improved understanding of WNK/SPAK-mediated KCC cell volume regulation in the nervous system might reveal novel avenues for the treatment of multiple neurological diseases.
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Affiliation(s)
- Kristopher T Kahle
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02114, USA; Manton Center for Orphan Disease Research, Children's Hospital Boston, 300 Longwood Avenue, Boston, MA 02114, USA.
| | - Arjun R Khanna
- Department of Neurosurgery, Boston Children's Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Seth L Alper
- Renal Division and Molecular and Vascular Medicine Division, Beth Israel Deaconess Medical Center; Department of Medicine, Harvard Medical School, Boston, MA 02215, USA
| | - Norma C Adragna
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Peter K Lauf
- Department of Pharmacology and Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA; Department of Pathology, Boonshoft School of Medicine, Wright State University, Dayton, OH 45435, USA
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA 15217, USA; Veterans Affairs Pittsburgh Health Care System, Geriatric Research, Educational and Clinical Center, Pittsburgh, PA 15213, USA
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
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Lin L, Yee SW, Kim RB, Giacomini KM. SLC transporters as therapeutic targets: emerging opportunities. Nat Rev Drug Discov 2015; 14:543-60. [PMID: 26111766 DOI: 10.1038/nrd4626] [Citation(s) in RCA: 501] [Impact Index Per Article: 55.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Solute carrier (SLC) transporters - a family of more than 300 membrane-bound proteins that facilitate the transport of a wide array of substrates across biological membranes - have important roles in physiological processes ranging from the cellular uptake of nutrients to the absorption of drugs and other xenobiotics. Several classes of marketed drugs target well-known SLC transporters, such as neurotransmitter transporters, and human genetic studies have provided powerful insight into the roles of more-recently characterized SLC transporters in both rare and common diseases, indicating a wealth of new therapeutic opportunities. This Review summarizes knowledge on the roles of SLC transporters in human disease, describes strategies to target such transporters, and highlights current and investigational drugs that modulate SLC transporters, as well as promising drug targets.
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Affiliation(s)
- Lawrence Lin
- Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California San Francisco, San Francisco, California 94158, USA
| | - Sook Wah Yee
- Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California San Francisco, San Francisco, California 94158, USA
| | - Richard B Kim
- Division of Clinical Pharmacology, Department of Medicine, University of Western Ontario, London Health Science Centre, London, Ontario N6A 5A5, Canada
| | - Kathleen M Giacomini
- 1] Department of Bioengineering and Therapeutic Sciences, Schools of Pharmacy and Medicine, University of California San Francisco, San Francisco, California 94158, USA. [2] Institute for Human Genetics, University of California San Francisco, San Francisco, California 94158, USA
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Abstract
The Na-K-2Cl cotransporter 2 (NKCC2) was thought to be kidney specific. Here we show expression in the brain hypothalamo-neurohypophyseal system (HNS), wherein upregulation follows osmotic stress. The HNS controls osmotic stability through the synthesis and release of the neuropeptide hormone, arginine vasopressin (AVP). AVP travels through the bloodstream to the kidney, where it promotes water conservation. Knockdown of HNS NKCC2 elicited profound effects on fluid balance following ingestion of a high-salt solution-rats produced significantly more urine, concomitant with increases in fluid intake and plasma osmolality. Since NKCC2 is the molecular target of the loop diuretics bumetanide and furosemide, we asked about their effects on HNS function following disturbed water balance. Dehydration-evoked GABA-mediated excitation of AVP neurons was reversed by bumetanide, and furosemide blocked AVP release, both in vivo and in hypothalamic explants. Thus, NKCC2-dependent brain mechanisms that regulate osmotic stability are disrupted by loop diuretics in rats.
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Orlov SN, Koltsova SV, Kapilevich LV, Gusakova SV, Dulin NO. NKCC1 and NKCC2: The pathogenetic role of cation-chloride cotransporters in hypertension. Genes Dis 2015; 2:186-196. [PMID: 26114157 PMCID: PMC4477834 DOI: 10.1016/j.gendis.2015.02.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/16/2015] [Indexed: 11/17/2022] Open
Abstract
This review summarizes the data on the functional significance of ubiquitous (NKCC1) and renal-specific (NKCC2) isoforms of electroneutral sodium, potassium and chloride cotransporters. These carriers contribute to the pathogenesis of hypertension via regulation of intracellular chloride concentration in vascular smooth muscle and neuronal cells and via sensing chloride concentration in the renal tubular fluid, respectively. Both NKCC1 and NKCC2 are inhibited by furosemide and other high-ceiling diuretics widely used for attenuation of extracellular fluid volume. However, the chronic usage of these compounds for the treatment of hypertension and other volume-expanded disorders may have diverse side-effects due to suppression of myogenic response in microcirculatory beds.
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Affiliation(s)
- Sergei N. Orlov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Russia
- Тomsk State University, Russia
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Thiazolidinediones and Edema: Recent Advances in the Pathogenesis of Thiazolidinediones-Induced Renal Sodium Retention. PPAR Res 2015; 2015:646423. [PMID: 26074951 PMCID: PMC4446477 DOI: 10.1155/2015/646423] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Accepted: 05/03/2015] [Indexed: 02/07/2023] Open
Abstract
Thiazolidinediones (TZDs) are one of the major classes of antidiabetic drugs that are used widely. TZDs improve insulin resistance by activating peroxisome proliferator-activated receptor gamma (PPARγ) and ameliorate diabetic and other nephropathies, at least, in experimental animals. However, TZDs have side effects, such as edema, congestive heart failure, and bone fracture, and may increase bladder cancer risk. Edema and heart failure, which both probably originate from renal sodium retention, are of great importance because these side effects make it difficult to continue the use of TZDs. However, the pathogenesis of edema remains a matter of controversy. Initially, upregulation of the epithelial sodium channel (ENaC) in the collecting ducts by TZDs was thought to be the primary cause of edema. However, the results of other studies do not support this view. Recent data suggest the involvement of transporters in the proximal tubule, such as sodium-bicarbonate cotransporter and sodium-proton exchanger. Other studies have suggested that sodium-potassium-chloride cotransporter 2 in the thick ascending limb of Henle and aquaporins are also possible targets for TZDs. This paper will discuss the recent advances in the pathogenesis of TZD-induced sodium reabsorption in the renal tubules and edema.
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Orlov SN, Koltsova SV, Kapilevich LV, Dulin NO, Gusakova SV. Cation-chloride cotransporters: Regulation, physiological significance, and role in pathogenesis of arterial hypertension. BIOCHEMISTRY (MOSCOW) 2015; 79:1546-61. [DOI: 10.1134/s0006297914130070] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Vorontsova I, Lam L, Delpire E, Lim J, Donaldson P. Identification of the WNK-SPAK/OSR1 signaling pathway in rodent and human lenses. Invest Ophthalmol Vis Sci 2014; 56:310-21. [PMID: 25515571 DOI: 10.1167/iovs.14-15911] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To identify whether the kinases that regulate the activity of cation chloride cotransporters (CCC) in other tissues are also expressed in rat and human lenses. METHODS The expression of with-no-lysine kinase (WNK 1, 3, 4), oxidative stress response kinase 1 (OSR1), and Ste20-like proline alanine rich kinase (SPAK) were determined at either the transcript or protein levels in the rat and human lenses by reverse-transcriptase PCR and/or Western blotting, respectively. Selected kinases were regionally and subcellularly characterized in rat and human lenses. The transparency, wet weight, and tissue morphology of lenses extracted from SPAK knock-out animals was compared with wild-type lenses. RESULTS WNK 1, 3, 4, SPAK, and OSR1 were identified at the transcript level in rat lenses and WNK1, 4, SPAK, and OSR1 expression confirmed at the protein level in both rat and human lenses. SPAK and OSR1 were found to associate with membranes as peripheral proteins and exhibited distinct subcellular and region-specific expression profiles throughout the lens. No significant difference in the wet weight of SPAK knock-out lenses was detected relative to wild-type lenses. However, SPAK knock-out lenses showed an increased susceptibility to opacification. CONCLUSIONS Our results show that the WNK 1, 3, 4, OSR1, and SPAK signaling system known to play a role in regulating the phosphorylation status, and hence activity of the CCCs in other tissues, is also present in the rat and human lenses. The increased susceptibility of SPAK lenses to opacification suggests that disruption of this signaling pathway may compromise the ability of the lens to control its volume, and its ability to maintain its transparency.
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Affiliation(s)
- Irene Vorontsova
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Leo Lam
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Eric Delpire
- Department of Anesthesiology, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Julie Lim
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand
| | - Paul Donaldson
- Department of Optometry and Vision Science, University of Auckland, New Zealand The New Zealand National Eye Centre, University of Auckland, New Zealand School of Medical Sciences, University of Auckland, New Zealand
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Hyodo S, Kakumura K, Takagi W, Hasegawa K, Yamaguchi Y. Morphological and functional characteristics of the kidney of cartilaginous fishes: with special reference to urea reabsorption. Am J Physiol Regul Integr Comp Physiol 2014; 307:R1381-95. [PMID: 25339681 DOI: 10.1152/ajpregu.00033.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
For adaptation to high-salinity marine environments, cartilaginous fishes (sharks, skates, rays, and chimaeras) adopt a unique urea-based osmoregulation strategy. Their kidneys reabsorb nearly all filtered urea from the primary urine, and this is an essential component of urea retention in their body fluid. Anatomical investigations have revealed the extraordinarily elaborate nephron system in the kidney of cartilaginous fishes, e.g., the four-loop configuration of each nephron, the occurrence of distinct sinus and bundle zones, and the sac-like peritubular sheath in the bundle zone, in which the nephron segments are arranged in a countercurrent fashion. These anatomical and morphological characteristics have been considered to be important for urea reabsorption; however, a mechanism for urea reabsorption is still largely unknown. This review focuses on recent progress in the identification and mapping of various pumps, channels, and transporters on the nephron segments in the kidney of cartilaginous fishes. The molecules include urea transporters, Na(+)/K(+)-ATPase, Na(+)-K(+)-Cl(-) cotransporters, and aquaporins, which most probably all contribute to the urea reabsorption process. Although research is still in progress, a possible model for urea reabsorption in the kidney of cartilaginous fishes is discussed based on the anatomical features of nephron segments and vascular systems and on the results of molecular mapping. The molecular anatomical approach thus provides a powerful tool for understanding the physiological processes that take place in the highly elaborate kidney of cartilaginous fishes.
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Affiliation(s)
- Susumu Hyodo
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Kawshiwa, Chiba, Japan
| | - Keigo Kakumura
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Kawshiwa, Chiba, Japan
| | - Wataru Takagi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Kawshiwa, Chiba, Japan
| | - Kumi Hasegawa
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Kawshiwa, Chiba, Japan
| | - Yoko Yamaguchi
- Laboratory of Physiology, Atmosphere and Ocean Research Institute, University of Tokyo, Kawshiwa, Chiba, Japan
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85
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Roy A, Goodman JH, Begum G, Donnelly BF, Pittman G, Weinman EJ, Sun D, Subramanya AR. Generation of WNK1 knockout cell lines by CRISPR/Cas-mediated genome editing. Am J Physiol Renal Physiol 2014; 308:F366-76. [PMID: 25477473 DOI: 10.1152/ajprenal.00612.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Sodium-coupled SLC12 cation chloride cotransporters play important roles in cell volume and chloride homeostasis, epithelial fluid secretion, and renal tubular salt reabsorption. These cotransporters are phosphorylated and activated indirectly by With-No-Lysine (WNK) kinases through their downstream effector kinases, Ste20- and SPS1-related proline alanine-rich kinase (SPAK) and oxidative stress-responsive kinase 1 (OSR1). Multiple WNK kinases can coexist within a single cell type, although their relative contributions to SPAK/OSR1 activation and salt transport remain incompletely understood. Deletion of specific WNKs from cells that natively express a functional WNK-SPAK/OSR1 network will help resolve these knowledge gaps. Here, we outline a simple method to selectively knock out full-length WNK1 expression from mammalian cells using RNA-guided clustered regularly interspaced short palindromic repeats/Cas9 endonucleases. Two clonal cell lines were generated by using a single-guide RNA (sgRNA) targeting exon 1 of the WNK1 gene, which produced indels that abolished WNK1 protein expression. Both cell lines exhibited reduced endogenous WNK4 protein abundance, indicating that WNK1 is required for WNK4 stability. Consistent with an on-target effect, the reduced WNK4 abundance was associated with increased expression of the KLHL3/cullin-3 E3 ubiquitin ligase complex and was rescued by exogenous WNK1 overexpression. Although the morphology of the knockout cells was indistinguishable from control, they exhibited low baseline SPAK/OSR1 activity and failed to trigger regulatory volume increase after hypertonic stress, confirming an essential role for WNK1 in cell volume regulation. Collectively, our data show how this new, powerful, and accessible gene-editing technology can be used to dissect and analyze WNK signaling networks.
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Affiliation(s)
- Ankita Roy
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Joshua H Goodman
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Gulnaz Begum
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Bridget F Donnelly
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Gabrielle Pittman
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Edward J Weinman
- Department of Medicine, University of Maryland Medical School, Baltimore, Maryland; and
| | - Dandan Sun
- Department of Neurology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
| | - Arohan R Subramanya
- Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; Veterans Affairs Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
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86
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Kaila K, Price TJ, Payne JA, Puskarjov M, Voipio J. Cation-chloride cotransporters in neuronal development, plasticity and disease. Nat Rev Neurosci 2014; 15:637-54. [PMID: 25234263 DOI: 10.1038/nrn3819] [Citation(s) in RCA: 498] [Impact Index Per Article: 49.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Electrical activity in neurons requires a seamless functional coupling between plasmalemmal ion channels and ion transporters. Although ion channels have been studied intensively for several decades, research on ion transporters is in its infancy. In recent years, it has become evident that one family of ion transporters, cation-chloride cotransporters (CCCs), and in particular K(+)-Cl(-) cotransporter 2 (KCC2), have seminal roles in shaping GABAergic signalling and neuronal connectivity. Studying the functions of these transporters may lead to major paradigm shifts in our understanding of the mechanisms underlying brain development and plasticity in health and disease.
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Affiliation(s)
- Kai Kaila
- 1] Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland. [2] Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland
| | - Theodore J Price
- University of Texas at Dallas, School of Behavior and Brain Sciences, Dallas, Texas 75093, USA
| | - John A Payne
- Department of Physiology and Membrane Biology, School of Medicine, University of California, Davis, California 95616, USA
| | - Martin Puskarjov
- 1] Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland. [2] Neuroscience Center, University of Helsinki, 00014 Helsinki, Finland
| | - Juha Voipio
- Department of Biosciences, University of Helsinki, 00014 Helsinki, Finland
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87
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Rasmussen LJH, Müller HSH, Jørgensen B, Pedersen SF, Hoffmann EK. Osmotic shrinkage elicits FAK- and Src phosphorylation and Src-dependent NKCC1 activation in NIH3T3 cells. Am J Physiol Cell Physiol 2014; 308:C101-10. [PMID: 25377086 DOI: 10.1152/ajpcell.00070.2014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The mechanisms linking cell volume sensing to volume regulation in mammalian cells remain incompletely understood. Here, we test the hypothesis that activation of nonreceptor tyrosine kinases Src, focal adhesion kinase (FAK), and Janus kinase-2 (Jak2) occurs after osmotic shrinkage of NIH3T3 fibroblasts and contributes to volume regulation by activation of NKCC1. FAK phosphorylation at Tyr397, Tyr576/577, and Tyr861 was increased rapidly after exposure to hypertonic (575 mOsm) saline, peaking after 10 (Tyr397, Tyr576/577) and 10-30 min (Tyr861). Shrinkage-induced Src family kinase autophosphorylation (pTyr416-Src) was induced after 2-10 min, and immunoprecipitation indicated that this reflected phosphorylation of Src itself, rather than Fyn and Yes. Phosphorylated Src and FAK partly colocalized with vinculin, a focal adhesion marker, after hypertonic shrinkage. The Src inhibitor pyrazolopyrimidine-2 (PP2, 10 μM) essentially abolished shrinkage-induced FAK phosphorylation at Tyr576/577 and Tyr861, yet not at Tyr397, and inhibited shrinkage-induced NKCC1 activity by ∼50%. The FAK inhibitor PF-573,228 augmented shrinkage-induced Src phosphorylation, and inhibited shrinkage-induced NKCC1 activity by ∼15%. The apparent role of Src in NKCC1 activation did not reflect phosphorylation of myosin light chain kinase (MLC), which was unaffected by shrinkage and by PP2, but may involve Jak2, a known target of Src, which was rapidly activated by osmotic shrinkage and inhibited by PP2. Collectively, our findings suggest a major role for Src and possibly the Jak2 axis in shrinkage-activation of NKCC1 in NIH3T3 cells, whereas no evidence was found for major roles for FAK and MLC in this process.
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Affiliation(s)
| | | | - Bente Jørgensen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | | | - Else Kay Hoffmann
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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Kemter E, Rathkolb B, Becker L, Bolle I, Busch DH, Dalke C, Elvert R, Favor J, Graw J, Hans W, Ivandic B, Kalaydjiev S, Klopstock T, Rácz I, Rozman J, Schrewe A, Schulz H, Zimmer A, Fuchs H, Gailus-Durner V, Hrabe de Angelis M, Wolf E, Aigner B. Standardized, systemic phenotypic analysis of Slc12a1I299F mutant mice. J Biomed Sci 2014; 21:68. [PMID: 25084970 PMCID: PMC4237776 DOI: 10.1186/s12929-014-0068-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Accepted: 07/17/2014] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Type I Bartter syndrome is a recessive human nephropathy caused by loss-of-function mutations in the SLC12A1 gene coding for the Na+-K+-2Cl- cotransporter NKCC2. We recently established the mutant mouse line Slc12a1I299F exhibiting kidney defects highly similar to the late-onset manifestation of this hereditary human disease. Besides the kidney defects, low blood pressure and osteopenia were revealed in the homozygous mutant mice which were also described in humans. Beside its strong expression in the kidney, NKCC2 has been also shown to be expressed in other tissues in rodents i.e. the gastrointestinal tract, pancreatic beta cells, and specific compartments of the ear, nasal tissue and eye. RESULTS To examine if, besides kidney defects, further organ systems and/or metabolic pathways are affected by the Slc12a1I299F mutation as primary or secondary effects, we describe a standardized, systemic phenotypic analysis of the mutant mouse line Slc12a1I299F in the German Mouse Clinic. Slc12a1I299F homozygous mutant mice and Slc12a1I299F heterozygous mutant littermates as controls were tested at the age of 4-6 months. Beside the already published changes in blood pressure and bone metabolism, a significantly lower body weight and fat content were found as new phenotypes for Slc12a1I299F homozygous mutant mice. Small additional effects included a mild erythropenic anemia in homozygous mutant males as well as a slight hyperalgesia in homozygous mutant females. For other functions, such as immunology, lung function and neurology, no distinct alterations were observed. CONCLUSIONS In this systemic analysis no clear primary effects of the Slc12a1I299F mutation appeared for the organs other than the kidneys where Slc12a1 expression has been described. On the other hand, long-term effects additional and/or secondary to the kidney lesions might also appear in humans harboring SLC12A1 mutations.
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