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Lang E, Bissinger R, Fajol A, Salker MS, Singh Y, Zelenak C, Ghashghaeinia M, Gu S, Jilani K, Lupescu A, Reyskens KMSE, Ackermann TF, Föller M, Schleicher E, Sheffield WP, Arthur JSC, Lang F, Qadri SM. Accelerated apoptotic death and in vivo turnover of erythrocytes in mice lacking functional mitogen- and stress-activated kinase MSK1/2. Sci Rep 2015; 5:17316. [PMID: 26611568 PMCID: PMC4661433 DOI: 10.1038/srep17316] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 10/28/2015] [Indexed: 12/25/2022] Open
Abstract
The mitogen- and stress-activated kinase MSK1/2 plays a decisive role in apoptosis. In analogy to apoptosis of nucleated cells, suicidal erythrocyte death called eryptosis is characterized by cell shrinkage and cell membrane scrambling leading to phosphatidylserine (PS) externalization. Here, we explored whether MSK1/2 participates in the regulation of eryptosis. To this end, erythrocytes were isolated from mice lacking functional MSK1/2 (msk−/−) and corresponding wild-type mice (msk+/+). Blood count, hematocrit, hemoglobin concentration and mean erythrocyte volume were similar in both msk−/− and msk+/+ mice, but reticulocyte count was significantly increased in msk−/− mice. Cell membrane PS exposure was similar in untreated msk−/− and msk+/+ erythrocytes, but was enhanced by pathophysiological cell stressors ex vivo such as hyperosmotic shock or energy depletion to significantly higher levels in msk−/− erythrocytes than in msk+/+ erythrocytes. Cell shrinkage following hyperosmotic shock and energy depletion, as well as hemolysis following decrease of extracellular osmolarity was more pronounced in msk−/− erythrocytes. The in vivo clearance of autologously-infused CFSE-labeled erythrocytes from circulating blood was faster in msk−/− mice. The spleens from msk−/− mice contained a significantly greater number of PS-exposing erythrocytes than spleens from msk+/+ mice. The present observations point to accelerated eryptosis and subsequent clearance of erythrocytes leading to enhanced erythrocyte turnover in MSK1/2-deficient mice.
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Affiliation(s)
- Elisabeth Lang
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany.,Department of Gastroenterology, Hepatology and Infectious Diseases, University of Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
| | - Rosi Bissinger
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Abul Fajol
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Madhuri S Salker
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Yogesh Singh
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Christine Zelenak
- Charité Medical University Berlin, Charitéplatz 1, 10117 Berlin, Germany
| | - Mehrdad Ghashghaeinia
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Shuchen Gu
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany.,Life Sciences Institute, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Kashif Jilani
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany.,Department of Biochemistry, University of Agriculture, 38040 Faisalabad, Pakistan
| | - Adrian Lupescu
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Kathleen M S E Reyskens
- MRC Phosphorylation Unit, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom.,Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Teresa F Ackermann
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Michael Föller
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany.,nstitute of Agricultural and Nutritional Sciences, Martin Luther University Halle-Wittenberg, Von-Danckelmann-Platz 2, 06120 Halle (Saale), Germany
| | - Erwin Schleicher
- Department of Internal Medicine, University of Tübingen, Otfried-Müller-Straβe 10, 72076 Tübingen, Germany
| | - William P Sheffield
- Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.,Centre for Innovation, Canadian Blood Services, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada
| | - J Simon C Arthur
- MRC Phosphorylation Unit, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom.,Division of Cell Signaling and Immunology, College of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, United Kingdom
| | - Florian Lang
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany
| | - Syed M Qadri
- Department of Physiology, University of Tübingen, Gmelinstr. 5, 72076 Tübingen, Germany.,Department of Pathology and Molecular Medicine, McMaster University, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada.,Centre for Innovation, Canadian Blood Services, 1280 Main Street West, Hamilton, Ontario L8S4K1, Canada
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Lang UE, Ackermann TF, Wolfer D, Schubert F, Sohr R, Hörtnagl H, Lang F, Gallinat J. Phosphoinositide-Dependent Protein Kinase 1 (PDK1). Zeitschrift für Psychologie 2015. [DOI: 10.1027/2151-2604/a000217] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Abstract. Phosphatidylinositol-3-kinase (PI3K) signaling influences susceptibility to virus infections, anoxia, obstetric complications, and cancer; which are changed in patients with schizophrenia and their first degree relatives. Therefore PI3K signaling might have impact on the pathophysiology of schizophrenia. PI3K signaling crucially involves phosphoinositide-dependent protein kinase (PDK1). Increased anxiety behavior is observed in PDK1 hypomorphic mice. Here we show enhanced prevalence of schizophrenia in carriers of the PDK1 CC genotype in human beings. Moreover, decreased parietal P300 amplitude, which is a well-studied schizophrenic endophenotype, was observed in PDK1 CC carriers. Glutamate and glutamine concentrations are increased in the frontal lobe of PDK1 dysmorphic mice and human CC individuals. Our results demonstrate that the PDK1 CC genotype is associated with increased risk to develop schizophrenia, a typical endophenotype profile observed in the disease and modified neurotransmitter concentrations in brain regions associated with the disease.
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Affiliation(s)
- Undine E. Lang
- Department of Psychiatry and Psychotherapy, University of Basel, Switzerland
| | | | - David Wolfer
- Institute of Anatomy, University of Zurich and Department of Biology, ETH Zurich, Switzerland
| | | | - Reinhard Sohr
- Department of Pharmacology, Charité University Medicine Berlin, Germany
| | - Heide Hörtnagl
- Department of Pharmacology, University of Innsbruck, Austria
| | - Florian Lang
- Department of Physiology I, University of Tuebingen, Germany
| | - Juergen Gallinat
- Department of Psychiatry and Psychotherapy, University Hospital Hamburg, Germany
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Leibrock C, Ackermann TF, Hierlmeier M, Lang F, Borgwardt S, Lang UE. Akt2 deficiency is associated with anxiety and depressive behavior in mice. Cell Physiol Biochem 2013; 32:766-77. [PMID: 24080829 DOI: 10.1159/000354478] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/26/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND The economic burden associated with major depressive disorder and anxiety disorders render both disorders the most common and debilitating psychiatric illnesses. To date, the exact cellular and molecular mechanisms underlying the pathophysiology, successful treatment and prevention of these highly associated disorders have not been identified. Akt2 is a key protein in the phosphatidylinositide-3 (PI3K) / glycogen synthase 3 kinase (GSK3) signaling pathway, which in turn is involved in brain-derived neurotrophic factor (BDNF) effects on fear memory, mood stabilisation and action of several antidepressant drugs. The present study thus explored the impact of Akt2 on behaviour of mice. METHODS Behavioural studies (Open-Field, Light-Dark box, O-Maze, Forced Swimming Test, Emergence Test, Object Exploration Test, Morris Water Maze, Radial Maze) have been performed with Akt2 knockout mice (akt(-/-)) and corresponding wild type mice (akt(+/+)). RESULTS Anxiety and depressive behavior was significantly higher in akt(-/-) than in akt(+/+) mice. The akt(-/-) mice were cognitively unimpaired but displayed increased anxiety in several behavioral tests (O-Maze test, Light-Dark box, Open Field test). Moreover, akt(-/-) mice spent more time floating in the Forced Swimming test, which is a classical feature of experimental depression. CONCLUSION Akt2 might be a key factor in the pathophysiology of depression and anxiety.
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Gulbins E, Palmada M, Reichel M, Lüth A, Böhmer C, Amato D, Müller CP, Tischbirek CH, Groemer TW, Tabatabai G, Becker KA, Tripal P, Staedtler S, Ackermann TF, van Brederode J, Alzheimer C, Weller M, Lang UE, Kleuser B, Grassmé H, Kornhuber J. Acid sphingomyelinase-ceramide system mediates effects of antidepressant drugs. Nat Med 2013; 19:934-8. [PMID: 23770692 DOI: 10.1038/nm.3214] [Citation(s) in RCA: 243] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2012] [Accepted: 04/23/2013] [Indexed: 01/18/2023]
Abstract
Major depression is a highly prevalent severe mood disorder that is treated with antidepressants. The molecular targets of antidepressants require definition. We investigated the role of the acid sphingomyelinase (Asm)-ceramide system as a target for antidepressants. Therapeutic concentrations of the antidepressants amitriptyline and fluoxetine reduced Asm activity and ceramide concentrations in the hippocampus, increased neuronal proliferation, maturation and survival and improved behavior in mouse models of stress-induced depression. Genetic Asm deficiency abrogated these effects. Mice overexpressing Asm, heterozygous for acid ceramidase, treated with blockers of ceramide metabolism or directly injected with C16 ceramide in the hippocampus had higher ceramide concentrations and lower rates of neuronal proliferation, maturation and survival compared with controls and showed depression-like behavior even in the absence of stress. The decrease of ceramide abundance achieved by antidepressant-mediated inhibition of Asm normalized these effects. Lowering ceramide abundance may thus be a central goal for the future development of antidepressants.
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Affiliation(s)
- Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany.
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Towhid ST, Liu GL, Ackermann TF, Beier N, Scholz W, Fuchß T, Toulany M, Rodemann HP, Lang F. Inhibition of Colonic Tumor Growth by the Selective SGK Inhibitor EMD638683. Cell Physiol Biochem 2013; 32:838-48. [DOI: 10.1159/000354486] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2013] [Indexed: 11/19/2022] Open
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Nasir O, Umbach AT, Rexhepaj R, Ackermann TF, Bhandaru M, Ebrahim A, Artunc F, Kempe DS, Puchchakayala G, Siraskar B, Föller M, Saeed A, Lang F. Effects of gum arabic (Acacia senegal) on renal function in diabetic mice. Kidney Blood Press Res 2012; 35:365-72. [PMID: 22473073 DOI: 10.1159/000336359] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2011] [Accepted: 01/05/2012] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Gum arabic (GA) is a Ca(2+)-, Mg(2+)- and K(+)-rich dietary fiber used for the treatment of patients with chronic kidney disease in Middle Eastern countries. In healthy mice, GA treatment increases creatinine clearance, renal ADH excretion, as well as intestinal and renal excretion of Mg(2+) and Ca(2+). GA decreases plasma Pi concentration, urinary Pi and Na(+) excretion. The present study explored the effects of GA on renal function in diabetic mice. METHODS Metabolic cage experiments were performed on Akita mice (akita(+/-)), which spontaneously develop insulin deficiency and thus hyperglycemia. Plasma and urinary concentrations of Na(+), K(+) and Ca(2+) were measured by flame photometry (AFM 5051, Eppendorf, Germany), creatinine by the Jaffé method, phosphate photometrically, urea by an enzymatic method, glucose utilizing a glucometer and an enzymatic kit, aldosterone using an RIA, urinary albumin fluorometrically, and blood pressure by the tail-cuff method. RESULTS GA (10% in drinking water) significantly increased urinary excretion of Ca(2+) and significantly decreased plasma phosphate and urea concentrations, urinary flow rate, urinary Na(+), phosphate and glucose excretion, blood pressure and proteinuria. CONCLUSIONS GA treatment decreases blood pressure and proteinuria in diabetic mice and may thus prove beneficial in diabetic nephropathy.
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Affiliation(s)
- Omaima Nasir
- Departments of Physiology, University of Tübingen, Tübingen, Germany
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Ackermann TF, Boini KM, Beier N, Scholz W, Fuchss T, Lang F. EMD638683, a novel SGK inhibitor with antihypertensive potency. Cell Physiol Biochem 2011; 28:137-46. [PMID: 21865856 DOI: 10.1159/000331722] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2011] [Indexed: 12/11/2022] Open
Abstract
UNLABELLED The serum- and glucocorticoid-inducible kinase 1 (SGK1) is transcriptionally upregulated by mineralocorticoids and activated by insulin. The kinase enhances renal tubular Na(+)-reabsorption and accounts for blood pressure increase following high salt diet in mice made hyperinsulinemic by dietary fructose or fat. The present study describes the in vitro and in vivo efficacy of a novel SGK1 inhibitor (EMD638683). EMD638683 was tested in vitro by determination of SGK1-dependent phosphorylation of NDRG1 (N-Myc downstream-regulated gene 1) in human cervical carcinoma HeLa-cells. In vivo EMD638683 (4460 ppm in chow, i.e. approx. 600 mg/kg/day) was administered to mice drinking tap water or isotonic saline containing 10% fructose. Blood pressure was determined by the tail cuff method, and urinary electrolyte (flame photometry) concentrations determined in metabolic cages. In vitro testing disclosed EMD638683 as a SGK1 inhibitor with an IC50 of 3 μM. Within 24 hours in vivo EMD638683 treatment significantly decreased blood pressure in fructose/saline-treated mice but not in control animals or in SGK1 knockout mice. EMD638683 failed to alter the blood pressure in SGK1 knockout mice. Following chronic (4 weeks) fructose/high salt treatment, additional EMD638683 treatment again decreased blood pressure. EMD638683 thus abrogates the salt sensitivity of blood pressure in hyperinsulinism without appreciably affecting blood pressure in the absence of hyperinsulinism. EMD638683 tended to increase fluid intake and urinary excretion of Na(+), significantly increased urinary flow rate and significantly decreased body weight. CONCLUSION EMD638683 could serve as a template for drugs counteracting hypertension in individuals with type II diabetes and metabolic syndrome.
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Föller M, Kempe DS, Boini KM, Pathare G, Siraskar B, Capuano P, Alesutan I, Sopjani M, Stange G, Mohebbi N, Bhandaru M, Ackermann TF, Judenhofer MS, Pichler BJ, Biber J, Wagner CA, Lang F. PKB/SGK-resistant GSK3 enhances phosphaturia and calciuria. J Am Soc Nephrol 2011; 22:873-80. [PMID: 21493770 DOI: 10.1681/asn.2010070757] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Insulin and IGF1-dependent signaling activates protein kinase B and serum and glucocorticoid inducible kinase (PKB/SGK), which together phosphorylate and inactivate glycogen synthase kinase GSK3. Because insulin and IGF1 increase renal tubular calcium and phosphorus reabsorption, we examined GSK3 regulation of phosphate transporter activity and determined whether PKB/SGK inactivates GSK3 to enhance renal phosphate and calcium transport. Overexpression of GSK3 and the phosphate transporter NaPi-IIa in Xenopus oocytes decreased electrogenic phosphate transport compared with NaPi-IIa-expressing oocytes. PKB/SGK serine phosphorylation sites in GSK3 were mutated to alanine to create gsk3(KI) mice resistant to PKB/SGK inactivation. Compared with wildtype animals, gsk3(KI) animals exhibited greater urinary phosphate and calcium clearances with higher excretion rates and lower plasma concentrations. Isolated brush border membranes from gsk3(KI) mice showed less sodium-dependent phosphate transport and Na-phosphate co-transporter expression. Parathyroid hormone, 1,25-OH vitamin D levels, and bone mineral density were decreased in gsk3(KI) mice, suggesting a global dysregulation of bone mineral metabolism. Taken together, PKB/SGK phosphorylation of GSK3 increases phosphate transporter activity and reduces renal calcium and phosphate loss.
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Affiliation(s)
- Michael Föller
- Department of Physiology, University of Tübingen, Tübingen, Germany
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9
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Kempe DS, Ackermann TF, Boini KM, Klaus F, Umbach AT, Dërmaku-Sopjani M, Judenhofer MS, Pichler BJ, Capuano P, Stange G, Wagner CA, Birnbaum MJ, Pearce D, Föller M, Lang F. Akt2/PKBbeta-sensitive regulation of renal phosphate transport. Acta Physiol (Oxf) 2010; 200:75-85. [PMID: 20236253 DOI: 10.1111/j.1748-1716.2010.02109.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
AIM The protein kinase B (PKB)/Akt is known to stimulate the cellular uptake of glucose and amino acids. The kinase is expressed in proximal renal tubules. The present study explored the influence of Akt/PKB on renal tubular phosphate transport. METHODS The renal phosphate transporter NaPi-IIa was expressed in Xenopus oocytes with or without PKB/Akt and Na(+) phosphate cotransport determined using dual electrode voltage clamp. Renal phosphate excretion was determined in Akt2/PKBbeta knockout mice (akt2(-/-)) and corresponding wild-type mice (akt2(+/+)). Transporter protein abundance was determined using Western blotting and phosphate transport by (32)P uptake into brush border membrane vesicles. RESULTS The phosphate-induced current in NaPi-IIa-expressing Xenopus oocytes was significantly increased by the coexpression of Akt/PKB. Phosphate excretion [micromol per 24 h per g BW] was higher by 91% in akt2(-/-) than in akt2(+/+) mice. The phosphaturia of akt2(-/-) mice occurred despite normal transport activity and expression of the renal phosphate transporters NaPi-IIa, NaPi-IIc and Pit2 in the brush border membrane, a significantly decreased plasma PTH concentration (by 46%) and a significantly enhanced plasma 1,25-dihydroxyvitamin D(3) concentration (by 46%). Moreover, fractional renal Ca(2+) excretion was significantly enhanced (by 53%) and bone density significantly reduced (by 11%) in akt2(-/-) mice. CONCLUSIONS Akt2/PKBbeta plays a role in the acute regulation of renal phosphate transport and thus contributes to the maintenance of phosphate balance and adequate mineralization of bone.
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Affiliation(s)
- D S Kempe
- Department of Physiology, University of Tübingen, Tübingen, Germany
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Fischer SS, Kempe DS, Leibrock CB, Rexhepaj R, Siraskar B, Boini KM, Ackermann TF, Föller M, Hocher B, Rosenblatt KP, Kuro-O M, Lang F. Hyperaldosteronism in Klotho-deficient mice. Am J Physiol Renal Physiol 2010; 299:F1171-7. [PMID: 20719979 DOI: 10.1152/ajprenal.00233.2010] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Klotho is a membrane protein participating in the inhibitory effect of FGF23 on the formation of 1,25-dihydroxyvitamin-D(3) [1,25(OH)(2)D(3)]. It participates in the regulation of renal tubular phosphate reabsorption and stimulates renal tubular Ca(2+) reabsorption. Klotho hypomorphic mice (klotho(hm)) suffer from severe growth deficit, rapid aging, and early death, events largely reversed by a vitamin D-deficient diet. The present study explored the role of Klotho deficiency in mineral and electrolyte metabolism. To this end, klotho(hm) mice and wild-type mice (klotho(+/+)) were subjected to a normal (D(+)) or vitamin D-deficient (D(-)) diet or to a vitamin D-deficient diet for 4 wk and then to a normal diet (D(-/+)). At the age of 8 wk, body weight was significantly lower in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice, klotho(hm)D(-) mice, and klotho(hm)D(-/+) mice. Plasma concentrations of 1,25(OH)(2)D(3,) adrenocorticotropic hormone (ACTH), antidiuretic hormone (ADH), and aldosterone were significantly higher in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice. Plasma volume was significantly smaller in klotho(hm)D(-/+) mice, and plasma urea, Ca(2+), phosphate and Na(+), but not K(+) concentrations were significantly higher in klotho(hm)D(+) mice than in klotho(+/+)D(+) mice. The differences were partially abrogated by a vitamin D-deficient diet. Moreover, the hyperaldosteronism was partially reversed by Ca(2+)-deficient diet. Ussing chamber experiments revealed a marked increase in amiloride-sensitive current across the colonic epithelium, pointing to enhanced epithelial sodium channel (ENaC) activity. A salt-deficient diet tended to decrease and a salt-rich diet significantly increased the life span of klotho(hm)D(+) mice. In conclusion, the present observation disclose that the excessive formation of 1,25(OH)(2)D(3) in Klotho-deficient mice results in extracellular volume depletion, which significantly contributes to the shortening of life span.
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Affiliation(s)
- Stephanie S Fischer
- Physiologisches Institut der Universität Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
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Nasir O, Wang K, Föller M, Bhandaru M, Sandulache D, Artunc F, Ackermann TF, Ebrahim A, Palmada M, Klingel K, Saeed AM, Lang F. Downregulation of Angiogenin Transcript Levels and Inhibition of Colonic Carcinoma by Gum Arabic (Acacia senegal). Nutr Cancer 2010; 62:802-10. [DOI: 10.1080/01635581003605920] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Ackermann TF, Kempe DS, Lang F, Lang UE. Hyperactivity and enhanced curiosity of mice expressing PKB/SGK-resistant glycogen synthase kinase-3 (GSK-3). Cell Physiol Biochem 2010; 25:775-86. [PMID: 20511724 DOI: 10.1159/000315097] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/25/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Mounting evidence suggests that bipolar disorder symptoms could be favorably influenced by modification of glycogen synthase kinase-3 (GSK-3) activity. Specifically, the well known antimanic and mood stabilizing medications lithium, valproate, olanzapine and clozapine have been shown to inhibit GSK-3 activity. GSK-3 is phosphorylated and thus inhibited by protein kinase B (PKB/Akt) and serum and glucocorticoid inducible kinase (SGK) isoforms. The present study explored, whether PKB/SGK-dependent GSK-3 regulation influences the behavior of mice. METHODS Gene-targeted knockin mice with mutated and thus PKB/SGK-resistant GSK-3alpha, beta (gsk-3(KI)) were compared to corresponding wild type mice (gsk-3(WT)). The mice were analyzed by open-field, light-dark (LD-) box, O-maze, emergence test, object exploration test and forced swimming test (FST). RESULTS In open-field, LD-box and O-maze, gsk-3(KI) mice displayed a hyperactive and more curious phenotype when compared to wild type mice. Speed and total distance moved as well as rearings were significantly increased in gsk-3(KI) compared to gsk-3(WT) mice. In the O-maze, gsk-3(KI) mice tended to travel a larger distance in the open, unprotected area thangsk-3(WT) mice, and performed significantly more unprotected head dips suggesting decreased anxiety behavior. In the forced swimming test, the immobility time was significantly decreased in gsk-3(KI) mice indicating a phenotype less prone to depression. Moreover, gsk-3(KI)mice were less sensitive to the application of chronic mild stress and showed a decreased HPA axis activity. CONCLUSIONS The present observations disclose a significant role of PKB/SGK-dependent regulation of GSK-3 in the control of activity, anxiety and proneness to depression. Accordingly, mice expressing SGK/PKB resistant GSK-3 may be a valuable model of hyperactivity and mania.
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Affiliation(s)
- Teresa F Ackermann
- Department of Physiology I, University of Tuebingen, 72076 Tuebingen, Germany
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Föller M, Kempe DS, Siraskar G, Fröhlich H, Ackermann TF, Siraskar B, Völkl H, Judenhofer M, Pichler B, Leavens KF, Birnbaum MJ, Pearce D, Lang F. Akt/PKB‐sensitive proximal tubular glucose and phosphate transport. FASEB J 2010. [DOI: 10.1096/fasebj.24.1_supplement.606.5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | | | | | | | | | | | - Harald Völkl
- Department of PhysiologyUniverstity of InnsbruckInnsbruckAustria
| | - Martin Judenhofer
- Department of RadiologyEberhard‐Karls‐University of TübingenTübingenGermany
| | - Bernd Pichler
- Department of RadiologyEberhard‐Karls‐University of TübingenTübingenGermany
| | - Karla F. Leavens
- Division of Endocrinology, Diabetes and MetabolismUniversity of PennsylvaniaPhiladelphiaPA
| | - Morris J. Birnbaum
- Division of Endocrinology, Diabetes and MetabolismUniversity of PennsylvaniaPhiladelphiaPA
| | - David Pearce
- Department of Medicine ‐ NephrologyUniversity of CaliforniaSan FranciscoCA
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Kempe DS, Siraskar G, Fröhlich H, Umbach AT, Stübs M, Weiss F, Ackermann TF, Völkl H, Birnbaum MJ, Pearce D, Föller M, Lang F. Regulation of renal tubular glucose reabsorption by Akt2/PKBβ. Am J Physiol Renal Physiol 2010; 298:F1113-7. [PMID: 20164156 DOI: 10.1152/ajprenal.00592.2009] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Akt/PKB is known to regulate the facilitative glucose carrier GLUT4. Nothing is known, however, of the role of Akt/PKB in the regulation of renal epithelial transport. To explore whether Akt2/PKBβ influences the Na(+)-coupled glucose cotransporter SGLT1, human SGLT1 was expressed in Xenopus laevis oocytes with or without Akt/PKB, and electrogenic glucose transport was determined by dual-electrode voltage clamp. The coexpression of Akt/PKB in SGLT1-expressing oocytes was followed by an increase in glucose-induced currents. To study the functional significance of Akt/PKB-sensitive renal glucose transport, further experiments were performed in gene-targeted mice lacking functional Akt2/PKBβ (akt2(-/-)) and in their wild-type littermates (akt2(+/+)). Plasma glucose concentration was significantly higher in akt2(-/-) mice than in akt2(+/+) mice but was virtually identical to the plasma glucose concentration in fructose-treated akt2(+/+) mice. Urinary glucose excretion was significantly higher in akt2(-/-) mice compared with akt2(+/+) mice with or without fructose treatment. Moreover, the glucose-induced depolarization of proximal tubular cells was significantly smaller in isolated, perfused renal tubules from akt2(-/-) mice than in those from akt2(+/+) mice. In conclusion, Akt2/PKBβ plays a role in the regulation of renal glucose transport.
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Affiliation(s)
- Daniela S Kempe
- Department of Physiology, University of Tübingen, Tübingen, Germany
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15
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Wang K, Gu S, Nasir O, Föller M, Ackermann TF, Klingel K, Kandolf R, Kuhl D, Stournaras C, Lang F. SGK1-dependent intestinal tumor growth in APC-deficient mice. Cell Physiol Biochem 2010; 25:271-8. [PMID: 20110688 DOI: 10.1159/000276561] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/12/2009] [Indexed: 11/19/2022] Open
Abstract
Adenomatous polyposis coli (APC) is inactivated in familial adenomatous polyposis and sporadic colorectal cancer. Mice carrying defective APC (apc(Min/+)) spontaneously develop gastrointestinal tumors. APC binds GSK3beta, which phosphorylates beta-catenin thus fostering its degradation. beta-catenin upregulates the serum- and glucocorticoid-inducible kinase Sgk1, which inhibits GSK3beta. The present study explored the role of SGK1 in tumor growth of apc(Min/+)mice. apc(Min/+)mice were crossed with SGK1-knockout mice (sgk1(-/-)) and their wild type littermates (sgk1(+/+)) generating apc(Min/+)/sgk1(-/-)mice and apc(Min/+)/sgk1(+/+)mice. beta-catenin abundance was determined by Western blotting and confocal microscopy. As a result apc(Min/+)/sgk1(+/+)mice developed significantly more intestinal tumors than apc(Min/+)/sgk1(-/-)mice. Following chemical cancerogenesis, colonic beta-catenin protein abundance was significantly higher in sgk1(+/+)mice than in sgk1(-/-)mice. beta-catenin expression was significantly increased in HEK293 cells treated with dexamethasone for upregulation of Sgk1. In conclusion, SGK1 expression favors the development of intestinal tumors in APC-deficient mice, an effect at least partially due to enhanced beta-catenin protein abundance.
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Affiliation(s)
- Kan Wang
- Department of Physiology, University of Tuebingen, 72076 Tuebingen, Germany
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16
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Nasir O, Wang K, Föller M, Gu S, Bhandaru M, Ackermann TF, Boini KM, Mack A, Klingel K, Amato R, Perrotti N, Kuhl D, Behrens J, Stournaras C, Lang F. Relative resistance of SGK1 knockout mice against chemical carcinogenesis. IUBMB Life 2009; 61:768-76. [PMID: 19548318 DOI: 10.1002/iub.209] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The serum and glucocorticoid inducible kinase SGK1 was originally cloned from mammary tumor cells. SGK1 was found to be up-regulated in a variety of tumors, but down-regulated in several distinct tumors. Thus, evidence for a role of SGK1 in tumor growth remained conflicting. According to in vitro observations, SGK1 is up-regulated by the oncogene beta-catenin and negatively regulates the proapoptotic transcription factor FOXO3a, which in turn stimulates transcription of the Bcl2-interacting mediator BIM. This study aimed to define the role of SGK1 in colon carcinoma in vivo. SGK1 knockout mice (sgk1(-/-)) and their wild type littermates (sgk1(+/+)) were subjected to chemical cancerogenesis (intraperitoneal injection of 20 mg/kg 1,2-dimethylhydrazine followed by three cycles of 30 g/L synthetic dextran sulfate sodium for 7 days). Moreover, SGK1 was silenced in HEK293 cells. FOXO3a and BIM protein abundance was determined by Western blotting and immunohistochemistry. Following chemical cancerogenesis, sgk1(-/-)mice developed significantly less colonic tumors than sgk1(+/+)mice. According to Western blotting and immunohistochemistry, SGK1 deficiency enhanced the expression of FOXO3a and BIM both, in vitro and in vivo. SGK1 deficiency counteracts the development of colonic tumors, an effect at least in part due to up-regulation of FOXO3a and BIM.
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Affiliation(s)
- Omaima Nasir
- Department of Physiology, University of Tuebingen, Germany
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17
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Boini KM, Graf D, Hennige AM, Koka S, Kempe DS, Wang K, Ackermann TF, Föller M, Vallon V, Pfeifer K, Schleicher E, Ullrich S, Häring HU, Häussinger D, Lang F. Enhanced insulin sensitivity of gene-targeted mice lacking functional KCNQ1. Am J Physiol Regul Integr Comp Physiol 2009; 296:R1695-701. [PMID: 19369585 DOI: 10.1152/ajpregu.90839.2008] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The pore-forming K+-channel alpha-subunit KCNQ1 is expressed in a wide variety of tissues including heart, skeletal muscle, liver, and epithelia. Most recent evidence revealed an association of the KCNQ1 gene with the susceptibility to type 2 diabetes. KCNQ1 participates in the regulation of cell volume, which is, in turn, critically important for the regulation of metabolism by insulin. The present study explored the influence of KCNQ1 on insulin-induced cellular K+ uptake and glucose metabolism. Insulin (100 nM)-induced K+ uptake was determined in isolated perfused livers from KCNQ1-deficient mice (kcnq1(-/-)) and their wild-type littermates (kcnq1(+/+)). Moreover, plasma glucose and insulin levels, intraperitoneal glucose (3 g/kg) tolerance, insulin (0.15 U/kg)-induced hypoglycemia, and peripheral uptake of radiolabeled 3H-deoxy-glucose were determined in both genotypes. Insulin-stimulated hepatocellular K+ uptake was significantly more sustained in isolated perfused livers from kcnq1(-/-) mice than from kcnq1(+/+)mice. The decline of plasma glucose concentration following an intraperitoneal injection of insulin was again significantly more sustained in kcnq1(-/-) than in kcnq1(+/+) mice. Both fasted and nonfasted plasma glucose and insulin concentrations were significantly lower in kcnq1(-/-) than in kcnq1(+/+)mice. Following an intraperitoneal glucose injection, the peak plasma glucose concentration was significantly lower in kcnq1(-/-) than in kcnq1(+/+)mice. Uptake of 3H-deoxy-glucose into skeletal muscle, liver, kidney and lung tissue was significantly higher in kcnq1(-/-) than in kcnq1(+/+)mice. In conclusion, KCNQ1 counteracts the stimulation of cellular K+ uptake by insulin and thereby influences K+-dependent insulin signaling on glucose metabolism. The observations indicate that KCNQ1 is a novel molecule affecting insulin sensitivity of glucose metabolism.
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Affiliation(s)
- Krishna M Boini
- Division of Diabetology, Endocrinology, Angiology, Nephrology, and Clinical Chemistry, University of Tuebingen, Tuebingen D-72076, Germany
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18
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Rotte A, Bhandaru M, Föller M, Biswas R, Mack AF, Friedrich B, Rexhepaj R, Nasir O, Ackermann TF, Boini KM, Kunzelmann K, Behrens J, Lang F. APC sensitive gastric acid secretion. Cell Physiol Biochem 2009; 23:133-42. [PMID: 19255508 DOI: 10.1159/000204102] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/01/2008] [Indexed: 11/19/2022] Open
Abstract
Adenomatous polyposis coli (APC) is a tumor suppressor gene inactivated in familial adenomatous polyposis and sporadic colorectal cancer. Mice carrying a loss-of-function mutation in the apc gene (apc(Min/+)) spontaneously develop gastrointestinal tumors. APC fosters degradation of beta-catenin, which in turn upregulates the serum- and glucocorticoid-inducible kinase SGK1. SGK1 stimulates KCNQ1, which is required for luminal K+ recycling and thus for gastric acid secretion. BCECF-fluorescence was utilized to determine gastric acid secretion in isolated gastric glands from apc(Min/+) mice and their wild type littermates (apc(+/+)). Western blotting was employed to analyse beta-catenin and SGK1 expression and immunohistochemistry to determine KCNQ1 protein abundance. beta-catenin and SGK1 expression were enhanced in apc(Min/+) mice. Cytosolic pH was similar in apc(Min/+) mice and apc(+/+) mice. Na+-independent pH recovery following an ammonium pulse (DeltapH/min), which reflects H+/K+ ATPase activity, was, however, significantly faster in apc(Min/+) mice than in apc(+/+)mice. In both genotypes DeltapH/min was abolished in the presence of H+/K+ ATPase inhibitor omeprazole (100 microM). Treatment of apc(Min/+) and apc(+/+)mice with 5 microM forskolin 15 minutes prior to the experiment or increase in local K+-concentrations to 35 mM (replacing Na+/NMDG) significantly increased DeltapH/min and abrogated the differences between genotypes. The increase of DeltapH/min in apc(Min/+)mice required SGK1, as it was abolished by additional knockout of SGK1 (apc(Min/+)/sgk1(-/-)). In conclusion, basal gastric acid secretion is significantly enhanced in apc(Min/+)mice, pointing to a role of APC in the regulation of gastric acid secretion. The effect of APC requires H+/K+ ATPase activity and is at least partially due to SGK1-dependent upregulation of KCNQ1.
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Affiliation(s)
- Anand Rotte
- Department of Physiology, University of Tubingen, Tubingen, Germany
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19
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Kempe DS, Ackermann TF, Fischer SS, Koka S, Boini KM, Mahmud H, Föller M, Rosenblatt KP, Kuro-O M, Lang F. Accelerated suicidal erythrocyte death in Klotho-deficient mice. Pflugers Arch 2009; 458:503-12. [PMID: 19184092 DOI: 10.1007/s00424-009-0636-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2008] [Revised: 12/23/2008] [Accepted: 01/08/2009] [Indexed: 01/30/2023]
Abstract
Klotho, a membrane protein mainly expressed in parathyroid glands, kidney, and choroid plexus, counteracts aging and increases the life span. Accordingly, life span is significantly shorter in Klotho-deficient mice (klotho(-/-)) than in their wild-type littermates (klotho(+/+)). The pleotropic effects of Klotho include inhibition of 1,25-dihydroxyvitamin D(3)(1,25(OH)(2)D(3)) formation. Vitamin D-deficient diet reverses the shortening of life span in klotho(-/-) mice. In a variety of cells, 1,25(OH)(2)D(3) stimulates Ca(2+) entry. In erythrocytes, increased Ca(2+) entry stimulates suicidal erythrocyte death, which is characterized by cell shrinkage and phosphatidylserine exposure at the erythrocyte surface. The present study explored the putative impact of Klotho on eryptosis. According to Fluo3 fluorescence, cytosolic Ca(2+) concentration was significantly larger in klotho(-/-) erythrocytes as compared to klotho(+/+) erythrocytes. According to annexin V-binding, phosphatidylserine exposure was significantly enhanced, and according to forward scatter, cell volume significantly decreased in klotho(-/-) erythrocytes as compared to klotho(+/+) erythrocytes. Energy depletion (13 h glucose depletion) and oxidative stress (35 min 1 mM tert-butyl-hydroxyl-peroxide [tert-BOOH]) increased phosphatidylserine exposure to values again significantly larger in klotho(-/-) erythrocytes as compared to klotho(+/+) erythrocytes. Reticulocyte number was significantly increased in klotho (-/-) mice, pointing to enhanced erythrocyte turnover. Vitamin D-deficient diet reversed the enhanced Ca(2+) entry and annexin V-binding of klotho(-/-) erythrocytes. The present observations reveal a novel function of Klotho, i.e., the at least partially vitamin D-dependent regulation of cytosolic Ca(2+) activity in and suicidal death of erythrocytes.
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Affiliation(s)
- Daniela S Kempe
- Department of Physiology, University of Tübingen, Tübingen, Germany
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20
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Ackermann TF, Boini KM, Völkl H, Bhandaru M, Bareiss PM, Just L, Vallon V, Amann K, Kuhl D, Feng Y, Hammes HP, Lang F. SGK1-sensitive renal tubular glucose reabsorption in diabetes. Am J Physiol Renal Physiol 2009; 296:F859-66. [PMID: 19158347 DOI: 10.1152/ajprenal.90238.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The hyperglycemia of diabetes mellitus increases the filtered glucose load beyond the maximal tubular transport rate and thus leads to glucosuria. Sustained hyperglycemia, however, may gradually increase the maximal renal tubular transport rate and thereby blunt the increase of urinary glucose excretion. The mechanisms accounting for the increase of renal tubular glucose transport have remained ill-defined. A candidate is the serum- and glucocorticoid-inducible kinase SGK1. The kinase has been shown to stimulate Na(+)-coupled glucose transport in vitro and mediate the stimulation of electrogenic intestinal glucose transport by glucocorticoids in vivo. SGK1 expression is confined to glomerula and distal nephron in intact kidneys but may extend to the proximal tubule in diabetic nephropathy. To explore whether SGK1 modifies glucose transport in diabetic kidneys, Akita mice (akita(+/-)), which develop spontaneous diabetes, have been crossbred with gene-targeted mice lacking SGK1 on one allele (sgk1(+/-)) to eventually generate either akita(+/-)/sgk1(-/-) or akita(+/-)/sgk1(+/+) mice. Both akita(+/-)/sgk1(-/-) and akita(+/-)/sgk1(+/+) mice developed profound hyperglycemia (>20 mM) within approximately 6 wk. Body weight and plasma glucose concentrations were not significantly different between these two genotypes. However, urinary excretion of glucose and urinary excretion of fluid, Na(+), and K(+), as well as plasma aldosterone concentrations, were significantly higher in akita(+/-)/sgk1(-/-) than in akita(+/-)/sgk1(+/+) mice. Studies in isolated perfused proximal tubules revealed that the electrogenic glucose transport was significantly lower in akita(+/-)/sgk1(-/-) than in akita(+/-)/sgk1(+/+) mice. The data provide the first evidence that SGK1 participates in the stimulation of renal tubular glucose transport in diabetic kidneys.
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Affiliation(s)
- Teresa F Ackermann
- Dept. of Physiology, Univ. of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany
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Ackermann TF, Hörtnagl H, Wolfer DP, Colacicco G, Sohr R, Lang F, Hellweg R, Lang UE. Phosphatidylinositide Dependent Kinase Deficiency Increases Anxiety and Decreases GABA and Serotonin Abundance in the Amygdala. Cell Physiol Biochem 2008; 22:735-44. [DOI: 10.1159/000185557] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2008] [Indexed: 11/19/2022] Open
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Rotte A, Bhandaru M, Ackermann TF, Boini KM, Lang F. Role of PDK1 in Regulation of Gastric Acid Secretion. Cell Physiol Biochem 2008; 22:725-34. [DOI: 10.1159/000185556] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/09/2008] [Indexed: 11/19/2022] Open
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