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Mwaura JG, Wekesa C, Ogutu PA, Okoth P. Whole Transcriptome Analysis of Differentially Expressed Genes in Cultured Nile Tilapia (O. niloticus) Subjected to Chronic Stress Reveals Signaling Pathways Associated with Depressed Growth. Genes (Basel) 2023; 14:genes14040795. [PMID: 37107553 PMCID: PMC10137778 DOI: 10.3390/genes14040795] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Revised: 03/11/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
Chronic stress is a serious threat to aquaculture as it lowers fish growth performance and compromises fish welfare. The exact mechanism by which growth is retarded is, however, not clearly understood. This study sought to elucidate the gene expression profiles associated with chronic stress in cultured Nile tilapia (Oreochromis niloticus) reared for 70 days at different ammonia concentrations and stocking densities. Fish in the treatment groups showed negative growth, while the controls showed positive allometric growth. The specific condition factor (Kn) ranged from 1.17 for the controls to 0.93 for the ammonia and 0.91 for the stocking density treatments. RNA was extracted from muscle tissue using TRIzol followed by library construction and Illumina sequencing. Comparative transcriptome analysis revealed 209 differentially expressed genes (DEGs) (156 up- and 53 down-regulated) in the ammonia and 252 DEGs (175 up- and 77 down-regulated) in the stocking density treatment. In both treatments, 24 and 17 common DEGs were up- and down-regulated, respectively. DEGs were significantly enriched in six pathways associated with muscle activity, energy mobilization and immunity. The heightened muscular activity consumes energy which would otherwise have been utilized for growth. These results bring to fore the molecular mechanisms underlying chronic stress’ suppression of growth in cultured Nile tilapia.
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Al-Shamasi AA, Elkaffash R, Mohamed M, Rayan M, Al-Khater D, Gadeau AP, Ahmed R, Hasan A, Eldassouki H, Yalcin HC, Abdul-Ghani M, Mraiche F. Crosstalk between Sodium-Glucose Cotransporter Inhibitors and Sodium-Hydrogen Exchanger 1 and 3 in Cardiometabolic Diseases. Int J Mol Sci 2021; 22:12677. [PMID: 34884494 PMCID: PMC8657861 DOI: 10.3390/ijms222312677] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/08/2021] [Accepted: 11/12/2021] [Indexed: 12/14/2022] Open
Abstract
Abnormality in glucose homeostasis due to hyperglycemia or insulin resistance is the hallmark of type 2 diabetes mellitus (T2DM). These metabolic abnormalities in T2DM lead to cellular dysfunction and the development of diabetic cardiomyopathy leading to heart failure. New antihyperglycemic agents including glucagon-like peptide-1 receptor agonists and the sodium-glucose cotransporter-2 inhibitors (SGLT2i) have been shown to attenuate endothelial dysfunction at the cellular level. In addition, they improved cardiovascular safety by exhibiting cardioprotective effects. The mechanism by which these drugs exert their cardioprotective effects is unknown, although recent studies have shown that cardiovascular homeostasis occurs through the interplay of the sodium-hydrogen exchangers (NHE), specifically NHE1 and NHE3, with SGLT2i. Another theoretical explanation for the cardioprotective effects of SGLT2i is through natriuresis by the kidney. This theory highlights the possible involvement of renal NHE transporters in the management of heart failure. This review outlines the possible mechanisms responsible for causing diabetic cardiomyopathy and discusses the interaction between NHE and SGLT2i in cardiovascular diseases.
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Affiliation(s)
- Al-Anood Al-Shamasi
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.-A.A.-S.); (R.E.); (M.M.); (M.R.); (D.A.-K.)
- Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha P.O. Box 2713, Qatar
| | - Rozina Elkaffash
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.-A.A.-S.); (R.E.); (M.M.); (M.R.); (D.A.-K.)
- Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha P.O. Box 2713, Qatar
| | - Meram Mohamed
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.-A.A.-S.); (R.E.); (M.M.); (M.R.); (D.A.-K.)
- Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha P.O. Box 2713, Qatar
| | - Menatallah Rayan
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.-A.A.-S.); (R.E.); (M.M.); (M.R.); (D.A.-K.)
- Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha P.O. Box 2713, Qatar
| | - Dhabya Al-Khater
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.-A.A.-S.); (R.E.); (M.M.); (M.R.); (D.A.-K.)
- Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha P.O. Box 2713, Qatar
| | - Alain-Pierre Gadeau
- INSERM, Biology of Cardiovascular Disease, University of Bordeaux, U1034 Pessac, France;
| | - Rashid Ahmed
- Department of Mechanical and Chemical Engineering, College of Engineering, Qatar University, Doha P.O. Box 2713, Qatar; (R.A.); (A.H.)
- Biomedical Research Centre (BRC), Qatar University, Doha P.O. Box 2713, Qatar;
| | - Anwarul Hasan
- Department of Mechanical and Chemical Engineering, College of Engineering, Qatar University, Doha P.O. Box 2713, Qatar; (R.A.); (A.H.)
- Biomedical Research Centre (BRC), Qatar University, Doha P.O. Box 2713, Qatar;
| | - Hussein Eldassouki
- College of Kinesiology, University of Saskatchewan, Saskatoon, SK S7N 5B5, Canada;
| | | | - Muhammad Abdul-Ghani
- Division of Diabetes, University of Texas Health Science Center at San Antonio, Floyd Curl Drive, San Antonio, TX 7703, USA;
| | - Fatima Mraiche
- Department of Pharmaceutical Sciences, College of Pharmacy, QU Health, Qatar University, Doha P.O. Box 2713, Qatar; (A.-A.A.-S.); (R.E.); (M.M.); (M.R.); (D.A.-K.)
- Biomedical and Pharmaceutical Research Unit, QU Health, Qatar University, Doha P.O. Box 2713, Qatar
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Manoli SS, Kisor K, Webb BA, Barber DL. Ethyl isopropyl amiloride decreases oxidative phosphorylation and increases mitochondrial fusion in clonal untransformed and cancer cells. Am J Physiol Cell Physiol 2021; 321:C147-C157. [PMID: 34038242 DOI: 10.1152/ajpcell.00001.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Many cancer cells, regardless of their tissue origin or genetic landscape, have increased expression or activity of the plasma membrane Na-H exchanger NHE1 and a higher intracellular pH (pHi) compared with untransformed cells. A current perspective that remains to be validated is that increased NHE1 activity and pHi enable a Warburg-like metabolic reprogramming of increased glycolysis and decreased mitochondrial oxidative phosphorylation. We tested this perspective and find it is not accurate for clonal pancreatic and breast cancer cells. Using the pharmacological reagent ethyl isopropyl amiloride (EIPA) to inhibit NHE1 activity and decrease pHi, we observe no change in glycolysis, as indicated by secreted lactate and intracellular pyruvate, despite confirming increased activity of the glycolytic enzyme phosphofructokinase-1 at higher pH. Also, in contrast to predictions, we find a significant decrease in oxidative phosphorylation with EIPA, as indicated by oxygen consumption rate (OCR). Decreased OCR with EIPA is not associated with changes in pathways that fuel oxidative phosphorylation or with mitochondrial membrane potential but occurs with a change in mitochondrial dynamics that includes a significant increase in elongated mitochondrial networks, suggesting increased fusion. These findings conflict with current paradigms on increased pHi inhibiting oxidative phosphorylation and increased oxidative phosphorylation being associated with mitochondrial fusion. Moreover, these findings raise questions on the suggested use of EIPA-like compounds to limit metabolic reprogramming in cancer cells.
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Affiliation(s)
- Sagar S Manoli
- Department of Cell and Tissue Biology, University of California, San Francisco, California
| | - Kyle Kisor
- Department of Cell and Tissue Biology, University of California, San Francisco, California
| | - Bradley A Webb
- Department of Biochemistry, West Virginia University, Morgantown, West Virginia
| | - Diane L Barber
- Department of Cell and Tissue Biology, University of California, San Francisco, California
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Bensimon A, Pizzagalli MD, Kartnig F, Dvorak V, Essletzbichler P, Winter GE, Superti-Furga G. Targeted Degradation of SLC Transporters Reveals Amenability of Multi-Pass Transmembrane Proteins to Ligand-Induced Proteolysis. Cell Chem Biol 2020; 27:728-739.e9. [PMID: 32386596 PMCID: PMC7303955 DOI: 10.1016/j.chembiol.2020.04.003] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 02/21/2020] [Accepted: 04/03/2020] [Indexed: 01/05/2023]
Abstract
With more than 450 members, the solute carrier (SLC) group of proteins represents the largest class of transporters encoded in the human genome. Their several-pass transmembrane domain structure and hydrophobicity contribute to the orphan status of many SLCs, devoid of known cargos or chemical inhibitors. We report that SLC proteins belonging to different families and subcellular compartments are amenable to induced degradation by heterobifunctional ligands. Engineering endogenous alleles via the degradation tag (dTAG) technology enabled chemical control of abundance of the transporter protein, SLC38A2. Moreover, we report the design of d9A-2, a chimeric compound engaging several members of the SLC9 family and leading to their degradation. d9A-2 impairs cellular pH homeostasis and promotes cell death in a range of cancer cell lines. These findings open the era of SLC-targeting chimeric degraders and demonstrate potential access of multi-pass transmembrane proteins of different subcellular localizations to the chemically exploitable degradation machinery.
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Affiliation(s)
- Ariel Bensimon
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Mattia D Pizzagalli
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Felix Kartnig
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Vojtech Dvorak
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Patrick Essletzbichler
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Georg E Winter
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria
| | - Giulio Superti-Furga
- CeMM Research Center for Molecular Medicine of the Austrian Academy of Sciences, 1090 Vienna, Austria; Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria.
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5
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Ye Y, Jia X, Bajaj M, Birnbaum Y. Dapagliflozin Attenuates Na +/H + Exchanger-1 in Cardiofibroblasts via AMPK Activation. Cardiovasc Drugs Ther 2019; 32:553-558. [PMID: 30367338 DOI: 10.1007/s10557-018-6837-3] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE We assessed whether the SGLT-2 inhibitor dapagliflozin (Dapa) attenuates the upregulation of the cardiac Na+/H+ exchanger (NHE-1) in vitro in mouse cardiofibroblasts stimulated with lipopolysaccharides (LPS) and whether this effect is dependent on adenosine monophosphate kinase (AMPK) activation. METHODS Mouse cardiofibroblasts were exposed for 16 h to Dapa (0.4 μM), AMPK activator (A769662 (10 μM)), AMPK inhibitor (compound C (CC) (10 μM)), an SGLT-1 and SGLT-2 inhibitor (phlorizin (PZ) (100 μM)), Dapa+CC, or Dapa+PZ, and then stimulated with LPS (10 ng/ml) for 3 h. NHE-1 mRNA levels were assessed by rt-PCR and total AMPK, phosphorylated-AMPK (P-AMPK), NHE-1, and heat shock protein-70 (Hsp70) protein levels in the whole cell lysate by immunoblotting. In addition, NHE-1 protein levels attached to Hsp70 were assessed by immunoprecipitation. RESULTS Exposure to LPS significantly reduced P-AMPK levels in the cardiofibroblasts. A769662 and Dapa equally increased P-AMPK. The effect was blocked by CC. Phlorizin had no effect on P-AMPK. LPS exposure significantly increased NHE-1 mRNA levels. Both Dapa and A769662 equally attenuated this increase. The effect of Dapa was blocked with CC. Interestingly, none of the compounds significantly affected NHE-1 and Hsp70 protein levels in the whole cell lysate. However, LPS significantly increased the concentration of NHE-1 attached to Hsp70. Both Dapa and A69662 attenuated this association and CC blocked the effect of Dapa. Again, phlorizin had no effect and did not alter the effect of Dapa. CONCLUSIONS Dapa increases P-AMPK in cardiofibroblasts exposed to LPS. Dapa attenuated the increase in NHE-1 mRNA and the association between NHE-1 and Hsp70. This effect was dependent on AMPK.
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Affiliation(s)
- Yumei Ye
- The Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX, USA
| | - Xiaoming Jia
- The Section of Cardiology, The Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA
| | - Mandeep Bajaj
- The Section of Endocrinology, The Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Yochai Birnbaum
- The Section of Cardiology, The Department of Medicine, Baylor College of Medicine, Houston, TX, 77030, USA.
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Intracellular signaling of the AMP-activated protein kinase. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2019; 116:171-207. [DOI: 10.1016/bs.apcsb.2018.12.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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AMP-Activated Protein Kinase (AMPK)-Dependent Regulation of Renal Transport. Int J Mol Sci 2018; 19:ijms19113481. [PMID: 30404151 PMCID: PMC6274953 DOI: 10.3390/ijms19113481] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 10/26/2018] [Accepted: 10/30/2018] [Indexed: 02/06/2023] Open
Abstract
AMP-activated kinase (AMPK) is a serine/threonine kinase that is expressed in most cells and activated by a high cellular AMP/ATP ratio (indicating energy deficiency) or by Ca2+. In general, AMPK turns on energy-generating pathways (e.g., glucose uptake, glycolysis, fatty acid oxidation) and stops energy-consuming processes (e.g., lipogenesis, glycogenesis), thereby helping cells survive low energy states. The functional element of the kidney, the nephron, consists of the glomerulus, where the primary urine is filtered, and the proximal tubule, Henle's loop, the distal tubule, and the collecting duct. In the tubular system of the kidney, the composition of primary urine is modified by the reabsorption and secretion of ions and molecules to yield final excreted urine. The underlying membrane transport processes are mainly energy-consuming (active transport) and in some cases passive. Since active transport accounts for a large part of the cell's ATP demands, it is an important target for AMPK. Here, we review the AMPK-dependent regulation of membrane transport along nephron segments and discuss physiological and pathophysiological implications.
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Álvarez-Cilleros D, Martín MÁ, Ramos S. Protective effects of (-)-epicatechin and the colonic metabolite 3,4-dihydroxyphenylacetic acid against glucotoxicity-induced insulin signalling blockade and altered glucose uptake and production in renal tubular NRK-52E cells. Food Chem Toxicol 2018; 120:119-128. [PMID: 29981789 DOI: 10.1016/j.fct.2018.07.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Revised: 06/26/2018] [Accepted: 07/02/2018] [Indexed: 01/24/2023]
Abstract
Glucotoxicity (high levels of glucose) is a major cause in the pathogenesis of diabetes. Evidences indicate that (-)-epicatechin (EC) and colonic metabolites derived from flavonoid intake could possess antidiabetic effects, but the mechanisms for their preventive activities related to glucose homeostasis and insulin signalling in the kidney remain largely unknown. This work is aimed to investigate the effect of EC and main colonic phenolic acids derived from flavonoid intake, i.e. 2,3-dihydroxybenzoic-acid, 3,4-dihydroxyphenylacetic-acid (DHPAA) and 3-hydroxyphenylpropionic-acid, on insulin signalling, and glucose production and uptake in renal tubular proximal NRK-52E cells treated with high glucose. Pre-treatment with EC or DHPAA prevented the decreased tyrosine-phosphorylated and total levels of IR caused by high glucose. EC and DHPAA pre-treatment also avoided the inactivation of the PI3K/AKT pathway and AMPK, and the elevation of PEPCK levels induced by high glucose. Additionally, EC and DHPAA pre-treatment alleviated the altered glucose uptake and production caused by high glucose, although this protective effect was abrogated when AKT and AMPK were inhibited. These results suggest EC and DHPAA prevent or delay a potential dysfunction of NRK-52E cells treated with high glucose through the attenuation of the insulin signalling blockade and the modulation of glucose homeostasis via AKT and AMPK.
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Affiliation(s)
- David Álvarez-Cilleros
- Department of Metabolism and Nutrition, Institute of Food Science and Technology and Nutrition (ICTAN), Consejo Superior de Investigaciones Científicas (CSIC), José Antonio Novais 10, Ciudad Universitaria, 28040, Madrid, Spain
| | - María Ángeles Martín
- Department of Metabolism and Nutrition, Institute of Food Science and Technology and Nutrition (ICTAN), Consejo Superior de Investigaciones Científicas (CSIC), José Antonio Novais 10, Ciudad Universitaria, 28040, Madrid, Spain; Centro de Investigación Biomédica en Red de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), ISCIII, Spain
| | - Sonia Ramos
- Department of Metabolism and Nutrition, Institute of Food Science and Technology and Nutrition (ICTAN), Consejo Superior de Investigaciones Científicas (CSIC), José Antonio Novais 10, Ciudad Universitaria, 28040, Madrid, Spain.
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Bissinger R, Malik A, Bouguerra G, Zhou Y, Singh Y, Abbès S, Lang F. Triggering of Suicidal Erythrocyte Death by the Antibiotic Ionophore Nigericin. Basic Clin Pharmacol Toxicol 2015; 118:381-9. [DOI: 10.1111/bcpt.12503] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2015] [Accepted: 10/06/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Rosi Bissinger
- Department of Physiology; University of Tuebingen; Tuebingen Germany
| | - Abaid Malik
- Department of Physiology; University of Tuebingen; Tuebingen Germany
| | - Ghada Bouguerra
- Department of Physiology; University of Tuebingen; Tuebingen Germany
- Laboratoire d'Hématologie Moléculaire et Cellulaire; Institut Pasteur de Tunis; Université de Tunis-El Manar; Tunis Tunisia
| | - Yuetao Zhou
- Department of Physiology; University of Tuebingen; Tuebingen Germany
| | - Yogesh Singh
- Department of Physiology; University of Tuebingen; Tuebingen Germany
| | - Salem Abbès
- Laboratoire d'Hématologie Moléculaire et Cellulaire; Institut Pasteur de Tunis; Université de Tunis-El Manar; Tunis Tunisia
| | - Florian Lang
- Department of Physiology; University of Tuebingen; Tuebingen Germany
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Acevedo-Olvera LF, Diaz-Garcia H, Parra-Barrera A, Caceres-Perez AA, Gutierrez-Iglesias G, Rangel-Corona R, Caceres-Cortes JR. Inhibition of the Na+/H+ antiporter induces cell death in TF-1 erythroleukemia cells stimulated by the stem cell factor. Cytokine 2015; 75:142-50. [PMID: 26188365 DOI: 10.1016/j.cyto.2015.06.020] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Revised: 06/03/2015] [Accepted: 06/23/2015] [Indexed: 01/17/2023]
Abstract
Leukemia cells produce acidic metabolites due to their high metabolic condition. An alkaline pHi (intracellular pH) shift, caused by activation of the Na+/H+ exchange, is an important event in the mechanism of growth factor activity. However, the role of the Na(+)/H(+) exchanger in the survival of erythroleukemia TF-1 cells has not yet been studied in detail. The aim of this study was to identify the effects of 5-(N-ethyl-N-isopropyl) amiloride (EIPA), a highly specific blocker of the Na(+)/H(+) exchanger, on the survival of SCF-dependent TF-1 cells. The effects of EIPA on survival and mitochondrial membrane potential were studied when exposing wild type TF-1 cells and TF-1 cells expressing bcl-2 to EIPA for 48h. Ectopic expression of the bcl-2 gene maintained a mildly alkaline pH and prevented the simultaneous appearance of apoptosis and autophagy (typically displayed by TF-1 cells) in the presence of EIPA. Consistent with Stem Cell Factor (SCF) function, we found that this molecule rescued TF-1 cells during autophagy but not apoptosis, allowing these cells to subsequently respond to GM-CSF. Serum deprivation or SCF withdrawal induced cell death at 36h in TF-1 and TF-1 neo cells, whereas TF-1/bcl-2 cells tended to undergo apoptosis and show acidic vacuoles after 96h, pointing to a transient anti-apoptotic effect. The present study shows the suppressive effect of EIPA on the proliferation of leukemia cell line stimulated with SCF, apparently by decreasing the mitochondria membrane potential and averting alkalinization. Through the constitutive expression of bcl-2, TF-1 cells were survival factor independent. Proliferation in these cells was not affected by EIPA at the concentrations used against parental TF-1 cells, indicating that the inhibitory effect in SCF-stimulated cells can be attributed to specific blocking of the Na(+)/H(+) exchanger.
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Affiliation(s)
- Leonardo Fermin Acevedo-Olvera
- Laboratorio de Cáncer y Hematopoyesis, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340, Mexico
| | - Hector Diaz-Garcia
- Laboratorio de Cáncer y Hematopoyesis, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340, Mexico
| | - Alberto Parra-Barrera
- Laboratorio de Cáncer y Hematopoyesis, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340, Mexico
| | - Alejandro Arturo Caceres-Perez
- Laboratorio de Cáncer y Hematopoyesis, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340, Mexico
| | - Gisela Gutierrez-Iglesias
- Laboratorio de Cáncer y Hematopoyesis, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340, Mexico
| | - Rosalva Rangel-Corona
- Laboratorio de Cáncer y Hematopoyesis, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340, Mexico
| | - Julio Roberto Caceres-Cortes
- Laboratorio de Cáncer y Hematopoyesis, Sección de Estudios de Posgrado e Investigación, Escuela Superior de Medicina, Instituto Politécnico Nacional, 11340, Mexico.
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Ameri K, Jahangiri A, Rajah AM, Tormos KV, Nagarajan R, Pekmezci M, Nguyen V, Wheeler ML, Murphy MP, Sanders TA, Jeffrey SS, Yeghiazarians Y, Rinaudo PF, Costello JF, Aghi MK, Maltepe E. HIGD1A Regulates Oxygen Consumption, ROS Production, and AMPK Activity during Glucose Deprivation to Modulate Cell Survival and Tumor Growth. Cell Rep 2015; 10:891-899. [PMID: 25683712 DOI: 10.1016/j.celrep.2015.01.020] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 10/27/2014] [Accepted: 01/09/2015] [Indexed: 02/07/2023] Open
Abstract
Hypoxia-inducible gene domain family member 1A (HIGD1A) is a survival factor induced by hypoxia-inducible factor 1 (HIF-1). HIF-1 regulates many responses to oxygen deprivation, but viable cells within hypoxic perinecrotic solid tumor regions frequently lack HIF-1α. HIGD1A is induced in these HIF-deficient extreme environments and interacts with the mitochondrial electron transport chain to repress oxygen consumption, enhance AMPK activity, and lower cellular ROS levels. Importantly, HIGD1A decreases tumor growth but promotes tumor cell survival in vivo. The human Higd1a gene is located on chromosome 3p22.1, where many tumor suppressor genes reside. Consistent with this, the Higd1a gene promoter is differentially methylated in human cancers, preventing its hypoxic induction. However, when hypoxic tumor cells are confronted with glucose deprivation, DNA methyltransferase activity is inhibited, enabling HIGD1A expression, metabolic adaptation, and possible dormancy induction. Our findings therefore reveal important new roles for this family of mitochondrial proteins in cancer biology.
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Affiliation(s)
- Kurosh Ameri
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Arman Jahangiri
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Anthony M Rajah
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Kathryn V Tormos
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Ravi Nagarajan
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Melike Pekmezci
- Department of Pathology, University of California San Francisco, San Francisco, CA 94143, USA
| | - Vien Nguyen
- Department of Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Matthew L Wheeler
- Department of Microbiology/Immunology, University of California San Francisco, San Francisco, CA 94143, USA
| | | | - Timothy A Sanders
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Stefanie S Jeffrey
- Department of Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yerem Yeghiazarians
- Department of Medicine/CVRI/Eli and Edythe Broad Center for Regeneration Medicine, University of California San Francisco, San Francisco, CA 94143, USA
| | - Paolo F Rinaudo
- Department of Obstetrics, Gynecology/Reproductive Sciences, University of California San Francisco, San Francisco, CA 94143, USA
| | - Joseph F Costello
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Manish K Aghi
- Department of Neurological Surgery, University of California San Francisco, San Francisco, CA 94143, USA
| | - Emin Maltepe
- Department of Pediatrics/Biomedical Sciences, University of California San Francisco, San Francisco, CA 94143, USA.
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Jinadasa T, Szabó EZ, Numat M, Orlowski J. Activation of AMP-activated protein kinase regulates hippocampal neuronal pH by recruiting Na(+)/H(+) exchanger NHE5 to the cell surface. J Biol Chem 2015; 289:20879-97. [PMID: 24936055 DOI: 10.1074/jbc.m114.555284] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Strict regulation of intra- and extracellular pH is an important determinant of nervous system function as many voltage-, ligand-, and H(+)-gated cationic channels are exquisitely sensitive to transient fluctuations in pH elicited by neural activity and pathophysiologic events such as hypoxia-ischemia and seizures. Multiple Na(+)/H(+) exchangers (NHEs) are implicated in maintenance of neural pH homeostasis. However, aside from the ubiquitous NHE1 isoform, their relative contributions are poorly understood. NHE5 is of particular interest as it is preferentially expressed in brain relative to other tissues. In hippocampal neurons, NHE5 regulates steady-state cytoplasmic pH, but intriguingly the bulk of the transporter is stored in intracellular vesicles. Here, we show that NHE5 is a direct target for phosphorylation by the AMP-activated protein kinase (AMPK), a key sensor and regulator of cellular energy homeostasis in response to metabolic stresses. In NHE5-transfected non-neuronal cells, activation of AMPK by the AMP mimetic AICAR or by antimycin A, which blocks aerobic respiration and causes acidification, increased cell surface accumulation and activity of NHE5, and elevated intracellular pH. These effects were effectively blocked by the AMPK antagonist compound C, the NHE inhibitor HOE694, and mutation of a predicted AMPK recognition motif in the NHE5 C terminus. This regulatory pathway was also functional in primary hippocampal neurons, where AMPK activation of NHE5 protected the cells from sustained antimycin A-induced acidification. These data reveal a unique role for AMPK and NHE5 in regulating the pH homeostasis of hippocampal neurons during metabolic stress.
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Al-bataineh MM, Gong F, Marciszyn AL, Myerburg MM, Pastor-Soler NM. Regulation of proximal tubule vacuolar H(+)-ATPase by PKA and AMP-activated protein kinase. Am J Physiol Renal Physiol 2014; 306:F981-95. [PMID: 24553431 PMCID: PMC4010682 DOI: 10.1152/ajprenal.00362.2013] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 02/13/2014] [Indexed: 11/22/2022] Open
Abstract
The vacuolar H(+)-ATPase (V-ATPase) mediates ATP-driven H(+) transport across membranes. This pump is present at the apical membrane of kidney proximal tubule cells and intercalated cells. Defects in the V-ATPase and in proximal tubule function can cause renal tubular acidosis. We examined the role of protein kinase A (PKA) and AMP-activated protein kinase (AMPK) in the regulation of the V-ATPase in the proximal tubule as these two kinases coregulate the V-ATPase in the collecting duct. As the proximal tubule V-ATPases have different subunit compositions from other nephron segments, we postulated that V-ATPase regulation in the proximal tubule could differ from other kidney tubule segments. Immunofluorescence labeling of rat ex vivo kidney slices revealed that the V-ATPase was present in the proximal tubule both at the apical pole, colocalizing with the brush-border marker wheat germ agglutinin, and in the cytosol when slices were incubated in buffer alone. When slices were incubated with a cAMP analog and a phosphodiesterase inhibitor, the V-ATPase accumulated at the apical pole of S3 segment cells. These PKA activators also increased V-ATPase apical membrane expression as well as the rate of V-ATPase-dependent extracellular acidification in S3 cell monolayers relative to untreated cells. However, the AMPK activator AICAR decreased PKA-induced V-ATPase apical accumulation in proximal tubules of kidney slices and decreased V-ATPase activity in S3 cell monolayers. Our results suggest that in proximal tubule the V-ATPase subcellular localization and activity are acutely coregulated via PKA downstream of hormonal signals and via AMPK downstream of metabolic stress.
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Affiliation(s)
- Mohammad M Al-bataineh
- Renal-Electrolyte Div., Dept. of Medicine, Scaife Hall A915, 3550 Terrace St., Pittsburgh, PA 15263.
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Membrane androgen receptor sensitive Na+/H+ exchanger activity in prostate cancer cells. FEBS Lett 2014; 588:1571-9. [PMID: 24607544 DOI: 10.1016/j.febslet.2014.02.040] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 02/13/2014] [Accepted: 02/20/2014] [Indexed: 11/22/2022]
Abstract
Membrane androgen receptors (mAR) are expressed in several tumors. mAR activation by testosterone albumin conjugates (TAC) suppresses tumor growth and migration. mAR signaling involves phosphoinositide-3-kinase (PI3K) and Rho-associated protein kinase (ROCK). PI3K stimulates serum- and glucocorticoid-inducible kinase SGK1, which in turn activates Na(+)/H(+)-exchangers (NHE). In prostate cancer cells cytosolic pH (pHi) was determined utilizing 2',7'-bis-(2-carboxyethyl)-5-(and-6)-carboxyfluorescein-fluorescence and NHE-activity utilizing Na(+)-dependent cytosolic realkalinization following an ammonium pulse. TAC (100 nM) significantly increased pHi and NHE-activity, effects abrogated by NHE1-inhibitor cariporide (10 μM), SGK1-inhibitors EMD638683 (50 μM) and GSK650349 (10 μM) and ROCK-inhibitors Y-27632 (10 μM) and fasudil (100 μM). TAC treatment rapidly and significantly increased cell volume and actin polymerization, effects abolished in the presence of cariporide. Thus, mAR-activation activates cariporide-sensitive Na(+)/H(+)-exchangers, an effect requiring SGK1 and ROCK activity.
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Dërmaku-Sopjani M, Abazi S, Faggio C, Kolgeci J, Sopjani M. AMPK-sensitive cellular transport. J Biochem 2014; 155:147-58. [PMID: 24440827 DOI: 10.1093/jb/mvu002] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
The energy sensing AMP-activated protein kinase (AMPK) regulates cellular and whole-body energy balance through stimulating catabolic ATP-generating and suppressing anabolic ATP-consuming pathways thereby helping cells survive during energy depletion. The kinase has previously been reported to be either directly or indirectly involved in the regulation of several carriers, channels and pumps of high significance in cellular physiology. Thus AMPK provides a necessary link between cellular energy metabolism and cellular transport activity. Better understanding of the AMPK role in cellular transport offers a potential for improved therapies in various human diseases and disorders. In this review, we discuss recent advances in understanding the role and function of AMPK in transport regulation under physiological and pathological states.
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Affiliation(s)
- Miribane Dërmaku-Sopjani
- Faculty of Medicine, University of Prishtina, Str. Bulevardi i Dëshmorëve, p.n. 10 000 Prishtina, Kosova; Department of Chemistry, University of Prishtina, Str. 'Nëna Terezë' p.n. 10 000 Prishtina, Kosova; Department of Chemistry, University of Tirana, Tirana, Albania; and Department of Biological and Environmental Sciences, University of Messina, Viale Ferdinando Stagno d'Alcontres, 31, 98166 S.Agata-Messina, Italy
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Lang F, Föller M. Regulation of ion channels and transporters by AMP-activated kinase (AMPK). Channels (Austin) 2013; 8:20-8. [PMID: 24366036 DOI: 10.4161/chan.27423] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The energy-sensing AMP-activated kinase AMPK ensures survival of energy-depleted cells by stimulating ATP production and limiting ATP utilization. Both energy production and energy consumption are profoundly influenced by transport processes across the cell membane including channels, carriers and pumps. Accordingly, AMPK is a powerful regulator of transport across the cell membrane. AMPK regulates diverse K(+) channels, Na(+) channels, Ca(2+) release activated Ca(2+) channels, Cl(-) channels, gap junctional channels, glucose carriers, Na(+)/H(+)-exchanger, monocarboxylate-, phosphate-, creatine-, amino acid-, peptide- and osmolyte-transporters, Na(+)/Ca(2+)-exchanger, H(+)-ATPase and Na(+)/K(+)-ATPase. AMPK activates ubiquitin ligase Nedd4-2, which labels several plasma membrane proteins for degradation. AMPK further regulates transport proteins by inhibition of Rab GTPase activating protein (GAP) TBC1D1. It stimulates phosphatidylinositol 3-phosphate 5-kinase PIKfyve and inhibits phosphatase and tensin homolog (PTEN) via glycogen synthase kinase 3β (GSK3β). Moreover, it stabilizes F-actin as well as downregulates transcription factor NF-κB. All those cellular effects serve to regulate transport proteins.
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Affiliation(s)
- Florian Lang
- Department of Physiology; University of Tübingen; Tübingen, Germany
| | - Michael Föller
- Department of Physiology; University of Tübingen; Tübingen, Germany
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Dërmaku-Sopjani M, Almilaji A, Pakladok T, Munoz C, Hosseinzadeh Z, Blecua M, Sopjani M, Lang F. Down-regulation of the Na+-coupled phosphate transporter NaPi-IIa by AMP-activated protein kinase. Kidney Blood Press Res 2013; 37:547-56. [PMID: 24356547 DOI: 10.1159/000355735] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS The Na(+)-coupled phosphate transporter NaPi-IIa is the main carrier accomplishing renal tubular phosphate reabsorption. It is driven by the electrochemical Na(+) gradient across the apical cell membrane, which is maintained by Na(+) extrusion across the basolateral cell membrane through the Na(+)/K(+) ATPase. The operation of NaPi-IIa thus requires energy in order to avoid cellular Na(+) accumulation and K(+) loss with eventual decrease of cell membrane potential, Cl(-) entry and cell swelling. Upon energy depletion, early inhibition of Na(+)-coupled transport processes may delay cell swelling and thus foster cell survival. Energy depletion is sensed by the AMP-activated protein kinase (AMPK), a serine/threonine kinase stimulating several cellular mechanisms increasing energy production and limiting energy utilization. The present study explored whether AMPK influences the activity of NAPi-IIa. METHODS cRNA encoding NAPi-IIa was injected into Xenopus oocytes with or without additional expression of wild-type AMPK (AMPK(α1)-HA+AMPK(β1)-Flag+AMPK(γ1)-HA), of inactive AMPK(αK45R) (AMPK(α1K45R)+AMPK(β1)-Flag+AMPK(γ1)-HA) or of constitutively active AMPK(γR70Q) (AMPK(α1)-HA+AMPK(β1)-Flag+AMPKγ1(R70Q)). NaPi-IIa activity was estimated from phosphate-induced current in dual electrode voltage clamp experiments. RESULTS In NaPi-IIa-expressing, but not in water-injected Xenopus oocytes, the addition of phosphate (1 mM) to the extracellular bath solution generated a current (Ip), which was significantly decreased by coexpression of wild-type AMPK and of AMPK(γR70Q) but not of AMPK(αK45R). The phosphate-induced current in NaPi-IIa- and AMPK-expressing Xenopus ooocytes was significantly increased by AMPK inhibitor Compound C (20 µM). Kinetic analysis revealed that AMPK significantly decreased the maximal transport rate. CONCLUSION The AMP-activated protein kinase AMPK is a powerful regulator of NaPi-IIa and thus of renal tubular phosphate transport. © 2013 S. Karger AG, Basel.
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Rogers AC, Huetter L, Hoekstra N, Collins D, Collaco A, Baird AW, Winter DC, Ameen N, Geibel JP, Kopic S. Activation of AMPK inhibits cholera toxin stimulated chloride secretion in human and murine intestine. PLoS One 2013; 8:e69050. [PMID: 23935921 PMCID: PMC3728293 DOI: 10.1371/journal.pone.0069050] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2013] [Accepted: 06/03/2013] [Indexed: 02/07/2023] Open
Abstract
Increased intestinal chloride secretion through chloride channels, such as the cystic fibrosis transmembrane conductance regulator (CFTR), is one of the major molecular mechanisms underlying enterotoxigenic diarrhea. It has been demonstrated in the past that the intracellular energy sensing kinase, the AMP-activated protein kinase (AMPK), can inhibit CFTR opening. We hypothesized that pharmacological activation of AMPK can abrogate the increased chloride flux through CFTR occurring during cholera toxin (CTX) mediated diarrhea. Chloride efflux was measured in isolated rat colonic crypts using real-time fluorescence imaging. AICAR and metformin were used to activate AMPK in the presence of the secretagogues CTX or forskolin (FSK). In order to substantiate our findings on the whole tissue level, short-circuit current (SCC) was monitored in human and murine colonic mucosa using Ussing chambers. Furthermore, fluid accumulation was measured in excised intestinal loops. CTX and forskolin (FSK) significantly increased chloride efflux in isolated colonic crypts. The increase in chloride efflux could be offset by using the AMPK activators AICAR and metformin. In human and mouse mucosal sheets, CTX and FSK increased SCC. AICAR and metformin inhibited the secretagogue induced rise in SCC, thereby confirming the findings made in isolated crypts. Moreover, AICAR decreased CTX stimulated fluid accumulation in excised intestinal segments. The present study suggests that pharmacological activation of AMPK effectively reduces CTX mediated increases in intestinal chloride secretion, which is a key factor for intestinal water accumulation. AMPK activators may therefore represent a supplemental treatment strategy for acute diarrheal illness.
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Affiliation(s)
- Ailín C. Rogers
- University College Dublin and St. Vincent's University Hospital, Dublin, Ireland
| | - Lisa Huetter
- Institute of Physiology and Pathophysiology, Paracelsus Medical University, Salzburg, Austria
- Department of Surgery, Yale University, School of Medicine, New Haven, Connecticut, United States of America
| | - Nadia Hoekstra
- Department of Pediatrics, Yale University, School of Medicine, New Haven, Connecticut, United States of America
| | - Danielle Collins
- University College Dublin and St. Vincent's University Hospital, Dublin, Ireland
| | - Anne Collaco
- Department of Pediatrics, Yale University, School of Medicine, New Haven, Connecticut, United States of America
| | - Alan W. Baird
- University College Dublin and St. Vincent's University Hospital, Dublin, Ireland
| | - Desmond C. Winter
- University College Dublin and St. Vincent's University Hospital, Dublin, Ireland
| | - Nadia Ameen
- Department of Pediatrics, Yale University, School of Medicine, New Haven, Connecticut, United States of America
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine, New Haven, Connecticut, United States of America
| | - John P. Geibel
- Department of Surgery, Yale University, School of Medicine, New Haven, Connecticut, United States of America
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine, New Haven, Connecticut, United States of America
| | - Sascha Kopic
- Department of Surgery, Yale University, School of Medicine, New Haven, Connecticut, United States of America
- Department of Cellular and Molecular Physiology, Yale University, School of Medicine, New Haven, Connecticut, United States of America
- * E-mail:
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Abstract
PURPOSE OF REVIEW The coupling of epithelial transport to underlying metabolic status is critical because solute transport processes normally consume a large proportion of total cellular energy. Recently, AMP-activated protein kinase (AMPK) has emerged as a critical transport regulator in tissues throughout the body. This review summarizes the role of AMPK in the regulation of renal epithelial transport, updates the growing list of AMPK transport protein targets and regulatory mechanisms, and discusses the potential clinical significance of this regulation in normal and disease states. RECENT FINDINGS Recent work has identified several new ion channels, transporters, and pumps that are regulated by AMPK in the kidney, and a better understanding of the mechanisms for the AMPK-dependent regulation of membrane transport proteins is emerging. Treatment with AMPK activators may be beneficial in preventing deleterious effects in the kidney in the setting of various diseases, including acute ischemia, diabetes mellitus and polycystic kidney disease, via mechanisms that depend at least partly on the regulatory effects of AMPK on solute transport. SUMMARY The energy-sensing kinase AMPK has a growing list of pleiotropic effects on cells and tissues, including its key role in the coupling of membrane transport to metabolic status in epithelial tissues like the kidney. AMPK is also involved in the coordination of hormonal, inflammatory, and other cellular stress pathway signals to produce an integrated effect on tubular transport. Identifying and characterizing new transport protein targets of AMPK should yield valuable new insights into various physiological and pathological processes in the kidney.
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Siraskar B, Huang DY, Pakladok T, Siraskar G, Sopjani M, Alesutan I, Kucherenko Y, Almilaji A, Devanathan V, Shumilina E, Föller M, Munoz C, Lang F. Downregulation of the renal outer medullary K(+) channel ROMK by the AMP-activated protein kinase. Pflugers Arch 2012. [PMID: 23179379 DOI: 10.1007/s00424-012-1180-1] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The 5'-adenosine monophosphate-activated serine/threonine protein kinase (AMPK) is stimulated by energy depletion, increase in cytosolic Ca(2+) activity, oxidative stress, and nitric oxide. AMPK participates in the regulation of the epithelial Na(+) channel ENaC and the voltage-gated K(+) channel KCNE1/KCNQ1. It is partially effective by decreasing PIP(2) formation through the PI3K pathway. The present study explored whether AMPK regulates the renal outer medullary K(+) channel ROMK. To this end, cRNA encoding ROMK was injected into Xenopus oocytes with and without additional injection of constitutively active AMPK(γR70Q) (AMPK(α1)-HA+AMPK(β1)-Flag+AMPKγ1(R70Q)), or of inactive AMPK(αK45R) (AMPK(α1K45R)+AMPK(β1)-Flag+AMPK(γ1)-HA), and the current determined utilizing two-electrode voltage-clamp and single channel patch clamp. ROMK protein abundance was measured utilizing chemiluminescence in Xenopus oocytes and western blot in whole kidney tissue. Moreover, renal Na(+) and K(+) excretion were determined in AMPK(α1)-deficient mice (ampk ( -/- )) and wild-type mice (ampk ( +/+ )) prior to and following an acute K(+) load (111 mM KCl, 30 mM NaHCO(3), 4.7 mM NaCl, and 2.25 g/dl BSA) at a rate of 500 μl/h. As a result, coexpression of AMPK(γR70Q) but not of AMPK(αK45R) significantly decreased the current in ROMK1-expressing Xenopus oocytes. Injection of phosphatidylinositol PI((4,5))P(2) significantly increased the current in ROMK1-expressing Xenopus oocytes, an effect reversed in the presence of AMPK(γR70Q). Under control conditions, no significant differences between ampk ( -/- ) and ampk ( +/+ ) mice were observed in glomerular filtration rate (GFR), urinary flow rate, serum aldosterone, plasma Na(+), and K(+) concentrations as well as absolute and fractional Na(+) and K(+) excretion. Following an acute K(+) load, GFR, urinary flow rate, serum aldosterone, plasma Na(+), and K(+) concentration were again similar in both genotypes, but renal absolute and fractional Na(+) and K(+) excretion were higher in ampk ( -/- ) than in ampk ( +/+ ) mice. According to micropuncture following a K(+) load, delivery of Na(+) to the early distal tubule but not delivery of K(+) to late proximal and early distal tubules was increased in ampk (-/-) mice. The upregulation of renal ROMK1 protein expression by acute K(+) load was more pronounced in ampk (-/-) than in ampk ( +/+ ) mice. In conclusion, AMPK downregulates ROMK, an effect compromising the ability of the kidney to excrete K(+) following an acute K(+) load.
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Mia S, Munoz C, Pakladok T, Siraskar G, Voelkl J, Alesutan I, Lang F. Downregulation of Kv1.5 K channels by the AMP-activated protein kinase. Cell Physiol Biochem 2012; 30:1039-50. [PMID: 23221389 DOI: 10.1159/000341480] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/03/2012] [Indexed: 12/28/2022] Open
Abstract
BACKGROUND The voltage gated K(+) channel Kv1.5 participates in the repolarization of a wide variety of cell types. Kv1.5 is downregulated during hypoxia, which is known to stimulate the energy-sensing AMP-activated serine/threonine protein kinase (AMPK). AMPK is a powerful regulator of nutrient transport and metabolism. Moreover, AMPK is known to downregulate several ion channels, an effect at least in part due to stimulation of the ubiquitin ligase Nedd4- 2. The present study explored whether AMPK regulates Kv1.5. METHODS cRNA encoding Kv1.5 was injected into Xenopus oocytes with and without additional injection of wild-type AMPK (α1 β 1γ1), of constitutively active (γR70Q)AMPK (α1 β 1γ1(R70Q)), of inactive mutant (αK45R)AMPK (α1(K45R)β1γ1), or of Nedd4-2. Kv1.5 activity was determined by two-electrode voltage-clamp. Moreover, Kv1.5 protein abundance in the cell membrane was determined by chemiluminescence and immunostaining with subsequent confocal microscopy. RESULTS Coexpression of wild-type AMPK(WT) and constitutively active AMPK(γR70Q), but not of inactive AMPK(αK45R) significantly reduced Kv1.5-mediated currents. Coexpression of constitutively active AMPKγR70Q further reduced Kv1.5 K(+) channel protein abundance in the cell membrane. Co-expression of Nedd4-2 similarly downregulated Kv1.5-mediated currents. CONCLUSION AMPK is a potent regulator of Kv1.5. AMPK inhibits Kv1.5 presumably in part by activation of Nedd4- 2 with subsequent clearance of channel protein from the cell membrane.
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Affiliation(s)
- Sobuj Mia
- Department of Physiology, University of Tübingen, Tübingen, Germany
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Zhang Y, Wang X, Sha S, Liang S, Zhao L, Liu L, Chai N, Wang H, Wu K. Berberine increases the expression of NHE3 and AQP4 in sennosideA-induced diarrhoea model. Fitoterapia 2012; 83:1014-22. [DOI: 10.1016/j.fitote.2012.05.015] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 05/23/2012] [Accepted: 05/26/2012] [Indexed: 11/28/2022]
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Lang F, Eylenstein A, Shumilina E. Regulation of Orai1/STIM1 by the kinases SGK1 and AMPK. Cell Calcium 2012; 52:347-54. [PMID: 22682960 DOI: 10.1016/j.ceca.2012.05.005] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2012] [Revised: 05/07/2012] [Accepted: 05/09/2012] [Indexed: 01/08/2023]
Abstract
STIM and Orai isoforms orchestrate store operated Ca2+ entry (SOCE) and thus cytosolic Ca2+ fluctuations following stimulation by hormones, growth factors and further mediators. Orai1 is a target of Nedd4-2, an ubiquitin ligase preparing several plasma membrane proteins for degradation. Phosphorylation of Nedd4-2 by the serum and glucocorticoid inducible kinase SGK1 leads to the binding of Nedd4-2 to the protein 14-3-3 thus preventing its interaction with Orai1. Nedd4-2 is activated by the energy sensing AMP activated kinase AMPK. Thus, SGK1 disrupts and AMPK fosters degradation of Orai1. New synthesis of both, Orai1 and STIM1, is stimulated by the transcription factor NF-κB (nuclear factor kappa B), which binds to the respective promoter regions of the genes encoding STIM1 and Orai1. SGK1 upregulates and AMPK presumably downregulates NF-κB and thus de novo synthesis of Orai1 and STIM1 proteins. The regulation by SGK1 links SOCE to the signaling of a wide variety of hormones and growth factors, the AMPK dependent regulation of Orai1 and STIM1 may serve to limit inadequate activation of SOCE following energy depletion, which is otherwise expected to activate SOCE by depletion of intracellular Ca2+ stores due to impairment of the ATP consuming sarco/endoplasmatic reticulum Ca2+ ATPase SERCA.
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Affiliation(s)
- Florian Lang
- Department of Physiology, University of Tübingen, Gmelinstr. 5, D-72076 Tübingen, Germany.
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Nurbaeva MK, Schmid E, Szteyn K, Yang W, Viollet B, Shumilina E, Lang F. Enhanced Ca²⁺ entry and Na+/Ca²⁺ exchanger activity in dendritic cells from AMP-activated protein kinase-deficient mice. FASEB J 2012; 26:3049-58. [PMID: 22474243 DOI: 10.1096/fj.12-204024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
In dendritic cells (DCs), chemotactic chemokines, such as CXCL12, rapidly increase cytosolic Ca(2+)concentrations ([Ca(2+)](i)) by triggering Ca(2+) release from intracellular stores followed by store-operated Ca(2+) (SOC) entry. Increase of [Ca(2+)](i) is blunted and terminated by Ca(2+) extrusion, accomplished by K(+)-independent Na(+)/Ca(2+) exchangers (NCXs) and K(+)-dependent Na(+)/Ca(2+) exchangers (NCKXs). Increased [Ca(2+)](i) activates energy-sensing AMP-activated protein kinase (AMPK), which suppresses proinflammatory responses of DCs and macrophages. The present study explored whether AMPK participates in the regulation of DC [Ca(2+)](i) and migration. DCs were isolated from AMPKα1-deficient (ampk(-/-)) mice and, as control, from their wild-type (ampk(+/+)) littermates. AMPKα1, Orai1-2, STIM1-2, and mitochondrial calcium uniporter protein expression was determined by Western blotting, [Ca(2+)](i) by Fura-2 fluorescence, SOC entry by inhibition of endosomal Ca(2+) ATPase with thapsigargin (1 μM), Na(+)/Ca(2+) exchanger activity from increase of [Ca(2+)](i), and respective whole-cell current in patch clamp following removal of extracellular Na(+). Migration was quantified utilizing transwell chambers. AMPKα1 protein is expressed in ampk(+/+) DCs but not in ampk(-/-) DCs. CXCL12 (300 ng/ml)-induced increase of [Ca(2+)](i), SOC entry, Orai 1 protein abundance, NCX, and NCKX were all significantly higher in ampk(-/-) DCs than in ampk(+/+) DCs. NCX and NCKX currents were similarly increased in ampk(-/-) DCs. Moreover, CXCL12 (50 ng/ml)-induced DC migration was enhanced in ampk(-/-) DCs. AMPK thus inhibits SOC entry, Na(+)/Ca(2+) exchangers, and migration of DCs.
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Wallace BK, Foroutan S, O'Donnell ME. Ischemia-induced stimulation of Na-K-Cl cotransport in cerebral microvascular endothelial cells involves AMP kinase. Am J Physiol Cell Physiol 2011; 301:C316-26. [PMID: 21562306 PMCID: PMC3154550 DOI: 10.1152/ajpcell.00517.2010] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2010] [Accepted: 05/09/2011] [Indexed: 11/22/2022]
Abstract
Increased blood-brain barrier (BBB) Na-K-Cl cotransporter activity appears to contribute to cerebral edema formation during ischemic stroke. We have shown previously that inhibition of BBB Na-K-Cl cotransporter activity reduces edema and infarct in the rat middle cerebral artery occlusion (MCAO) model of ischemic stroke. We have also shown that the BBB cotransporter is stimulated by the ischemic factors hypoxia, aglycemia, and arginine vasopressin (AVP), although the mechanisms responsible are not well understood. AMP-activated protein kinase (AMPK), a key mediator of cell responses to stress, can be activated by a variety of stresses, including ischemia, hypoxia, and aglycemia. Previous studies have shown that the AMPK inhibitor Compound C significantly reduces infarct in mouse MCAO. The present study was conducted to evaluate the possibility that AMPK participates in ischemic factor-induced stimulation of the BBB Na-K-Cl cotransporter. Cerebral microvascular endothelial cells (CMEC) were assessed for Na-K-Cl cotransporter activity as bumetanide-sensitive (86)Rb influx. AMPK activity was assessed by Western blot analysis and immunofluorescence methods using antibodies that detect total versus phosphorylated (activated) AMPK. We found that hypoxia (7% and 2% O(2)), aglycemia, AVP, and oxygen-glucose deprivation (5- to 120-min exposures) increase activation of AMPK. We also found that Compound C inhibition of AMPK reduces hypoxia-, aglycemia-, and AVP-induced stimulation of CMEC Na-K-Cl cotransporter activity. Confocal immunofluorescence of perfusion-fixed rat brain slices revealed the presence of AMPK, both total and phosphorylated kinase, in BBB in situ of both control and ischemic brain. These findings suggest that ischemic factor stimulation of the BBB Na-K-Cl cotransporter involves activation of AMPK.
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Affiliation(s)
- Breanna K Wallace
- Department of Physiology and Membrane Biology, University of California, Davis, CA 95616, USA
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Alesutan I, Munoz C, Sopjani M, Dërmaku-Sopjani M, Michael D, Fraser S, Kemp BE, Seebohm G, Föller M, Lang F. Inhibition of Kir2.1 (KCNJ2) by the AMP-activated protein kinase. Biochem Biophys Res Commun 2011; 408:505-10. [PMID: 21501591 DOI: 10.1016/j.bbrc.2011.04.015] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2011] [Accepted: 04/03/2011] [Indexed: 11/18/2022]
Abstract
The inward rectifier K(+) channel Kir2.1 participates in the maintenance of the cell membrane potential in a variety of cells including neurons and cardiac myocytes. Mutations of KCNJ2 encoding Kir2.1 underlie the Andersen-Tawil syndrome, a rare disorder clinically characterized by periodic paralysis, cardiac arrhythmia and skeletal abnormalities. The maintenance of the cardiac cell membrane potential is decreased in ischaemia, which is known to stimulate the AMP-activated serine/threonine protein kinase (AMPK). This energy-sensing kinase stimulates energy production and limits energy utilization. The present study explored whether AMPK regulates Kir2.1. To this end, cRNA encoding Kir2.1 was injected into Xenopus oocytes with and without additional injection of wild type AMPK (AMPKα1+AMPKβ1+AMPKγ1), of the constitutively active (γR70Q)AMPK (α1β1γ1(R70Q)), of the kinase dead mutant (αK45R)AMPK (α1(K45R)β1γ1), or of the ubiquitin ligase Nedd4-2. Kir2.1 activity was determined in two-electrode voltage-clamp experiments. Moreover, Kir2.1 protein abundance in the cell membrane was determined by immunostaining and subsequent confocal imaging. As a result, wild type and constitutively active AMPK significantly reduced Kir2.1-mediated currents and Kir2.1 protein abundance in the cell membrane. Expression of wild type Nedd4-2 or of Nedd4-2(S795A) lacking an AMPK phosphorylation consensus sequence downregulated Kir2.1 currents. The effect of wild type Nedd4-2 but not of Nedd4-2(S795A) was significantly augmented by additional coexpression of AMPK. In conclusion, AMPK is a potent regulator of Kir2.1. AMPK is at least partially effective through phosphorylation of the ubiquitin ligase Nedd4-2.
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Affiliation(s)
- Ioana Alesutan
- Department of Physiology, University of Tübingen, Gmelinstrasse 5, Tübingen, Germany
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