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Nakamura K, Komagiri Y, Kubokawa M. Interleukin-1β suppresses activity of an inwardly rectifying K+ channel in human renal proximal tubule cells. J Physiol Sci 2013; 63:377-87. [PMID: 23797607 PMCID: PMC10717820 DOI: 10.1007/s12576-013-0275-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Accepted: 06/10/2013] [Indexed: 12/12/2022]
Abstract
We investigated the effect of interleukin-1β (IL-1β) on activity of an inwardly rectifying K+ channel in cultured human proximal tubule cells (RPTECs), using the patch-clamp technique and Fura-2 Ca2+ imaging. IL-1β (15 pg/ml) acutely reduced K+ channel activity in cell-attached patches. This effect was blocked by the IL-1 receptor antagonist (20 ng/ml), an inhibitor of phospholipase C, neomycin (300 μM), and an inhibitor of protein kinase C (PKC), GF109203X (500 nM). The Fura-2 Ca2+ imaging revealed that IL-1β increased intracellular Ca2+ concentration even after removal of extracellular Ca2+, which was blocked by an inhibitor of inositol 1,4,5-trisphosphate receptors, 2-aminoethoxydiphenyl borate (2-APB, 1 μM). Moreover, IL-1β suppressed channel activity in the presence of 2-APB without extracellular Ca2+. These results suggest that IL-1β suppresses K+ channel activity in RPTECs through binding to its specific receptor and activation of the PKC pathway even though intracellular Ca2+ does not increase.
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Affiliation(s)
- Kazuyoshi Nakamura
- Department of Physiology, Iwate Medical University School of Medicine, 2-1-1 Nishitokuta, Yahaba, 028-3694 Japan
| | - You Komagiri
- Department of Physiology, Iwate Medical University School of Medicine, 2-1-1 Nishitokuta, Yahaba, 028-3694 Japan
| | - Manabu Kubokawa
- Department of Physiology, Iwate Medical University School of Medicine, 2-1-1 Nishitokuta, Yahaba, 028-3694 Japan
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Carvalho JG, Leite ADL, Peres-Buzalaf C, Salvato F, Labate CA, Everett ET, Whitford GM, Buzalaf MAR. Renal proteome in mice with different susceptibilities to fluorosis. PLoS One 2013; 8:e53261. [PMID: 23308176 PMCID: PMC3537663 DOI: 10.1371/journal.pone.0053261] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2012] [Accepted: 11/27/2012] [Indexed: 11/19/2022] Open
Abstract
A/J and 129P3/J mouse strains have different susceptibilities to dental fluorosis due to their genetic backgrounds. They also differ with respect to several features of fluoride (F) metabolism and metabolic handling of water. This study was done to determine whether differences in F metabolism could be explained by diversities in the profile of protein expression in kidneys. Weanling, male A/J mice (susceptible to dental fluorosis, n = 18) and 129P3/J mice (resistant, n = 18) were housed in pairs and assigned to three groups given low-F food and drinking water containing 0, 10 or 50 ppm [F] for 7 weeks. Renal proteome profiles were examined using 2D-PAGE and LC-MS/MS. Quantitative intensity analysis detected between A/J and 129P3/J strains 122, 126 and 134 spots differentially expressed in the groups receiving 0, 10 and 50 ppmF, respectively. From these, 25, 30 and 32, respectively, were successfully identified. Most of the proteins were related to metabolic and cellular processes, followed by response to stimuli, development and regulation of cellular processes. In F-treated groups, PDZK-1, a protein involved in the regulation of renal tubular reabsorption capacity was down-modulated in the kidney of 129P3/J mice. A/J and 129P3/J mice exhibited 11 and 3 exclusive proteins, respectively, regardless of F exposure. In conclusion, proteomic analysis was able to identify proteins potentially involved in metabolic handling of F and water that are differentially expressed or even not expressed in the strains evaluated. This can contribute to understanding the molecular mechanisms underlying genetic susceptibility to dental fluorosis, by indicating key-proteins that should be better addressed in future studies.
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Affiliation(s)
- Juliane Guimarães Carvalho
- Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil
| | - Aline de Lima Leite
- Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil
| | - Camila Peres-Buzalaf
- Department of Biological Sciences, Bauru Dental School, University of São Paulo, Bauru, São Paulo, Brazil
| | - Fernanda Salvato
- Department of Genetics, Escola Superior de Agricultura “Luiz de Queiros”, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Carlos Alberto Labate
- Department of Genetics, Escola Superior de Agricultura “Luiz de Queiros”, University of São Paulo, Piracicaba, São Paulo, Brazil
| | - Eric T. Everett
- Department of Pediatric Dentistry, School of Dentistry, The Carolina Center for Genome Sciences, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, United States of America
| | - Gary Milton Whitford
- Department of Oral Biology, School of Dentistry, The Medical College of Georgia, Augusta, Georgia, United States of America
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Mori Y, Yoshida H, Miyamoto M, Sohma Y, Kubota T. Constitutive Activity of Inwardly Rectifying K+ Channel at Physiological [Ca]i Is Mediated by Ca2+/CaMK II Pathway in Opossum Kidney Proximal Tubule Cells. J Physiol Sci 2008; 58:199-207. [DOI: 10.2170/physiolsci.rp014507] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2007] [Accepted: 05/18/2008] [Indexed: 11/05/2022]
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Nakamura K, Hirano J, Itazawa SI, Kubokawa M. Protein kinase G activates inwardly rectifying K(+) channel in cultured human proximal tubule cells. Am J Physiol Renal Physiol 2002; 283:F784-91. [PMID: 12217870 DOI: 10.1152/ajprenal.00023.2002] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
An ATP-regulated inwardly rectifying K(+) channel, whose activity is enhanced by PKA, is present in the plasma membrane of cultured human proximal tubule cells. In this study, we investigated the effects of PKG on this K(+) channel, using the patch-clamp technique. In cell-attached patches, bath application of a membrane-permeant cGMP analog, 8-bromoguanosine 3',5'-monophosphate (8-BrcGMP; 100 microM), stimulated channel activity, whereas application of a PKG-specific inhibitor, KT-5823 (1 microM), reduced the activity. Channel activation induced by 8-BrcGMP was observed even in the presence of a PKA-specific inhibitor, KT-5720 (500 nM), which was abolished by KT-5823. Direct effects of cGMP and PKG were examined with inside-out patches in the presence of 1 mM MgATP. Although cytoplasmic cGMP (100 microM) alone had little effect on channel activity, subsequent addition of PKG (500 U/ml) enhanced it. Furthermore, bath application of atrial natriuretic peptide (ANP; 20 nM) in cell-attached patches stimulated channel activity, which was blocked by KT-5823. In conclusion, cGMP/PKG-dependent processes participate in activating the ATP-regulated K(+) channel and producing the stimulatory effect of ANP on channel activity.
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Affiliation(s)
- Kazuyoshi Nakamura
- Department of Physiology II, Iwate Medical University School of Medicine, Morioka 020-8505, Japan
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