1
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Sohail S, Akkawi G, Rechter T, Fluitt MB, Ecelbarger CM. Sex Modulates Response to Renal-Tubule-Targeted Insulin Receptor Deletion in Mice. Int J Mol Sci 2023; 24:8056. [PMID: 37175762 PMCID: PMC10178497 DOI: 10.3390/ijms24098056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 04/19/2023] [Accepted: 04/27/2023] [Indexed: 05/15/2023] Open
Abstract
Insulin facilitates renal sodium reabsorption and attenuates gluconeogenesis. Sex differences in this regulation have not been well characterized. Using tetracycline-inducible Cre-lox recombination, we knocked out (KO) the insulin receptor (InsR) from the renal tubule in adult male (M) and female (F) mice (C57Bl6 background) with a paired box 8 (PAX8) promoter. Body weights were not affected by the KO, but mean kidney weights were reduced in the KO mice (13 and 3%, in M and F, respectively, relative to wild-type (WT) mice). A microscopic analysis revealed 25 and 19% reductions in the proximal tubule (PT) and cortical collecting duct cell heights, respectively, in KOMs relative to WTMs. The reductions were 5 and 11% for KOFs. Western blotting of renal cortex homogenates showed decreased protein levels for the β and γ subunits of the epithelial sodium channel (ENaC) and the sodium-potassium-2-chloride cotransporter type 2 (NKCC2) in both sexes of KO mice; however, α-ENaC was upregulated in KOMs and downregulated in KOFs. Both sexes of KO mice cleared exogenously administered glucose faster than the WT mice and had lower semi-fasted, anesthetized blood glucose levels. However, KOMs (but not KOFs) demonstrated evidence of enhanced renal gluconeogenesis, including higher levels of renal glucose-6-phosphatase, the PT's production of glucose, post-prandial blood glucose, and plasma insulin, whereas KOFs exhibited downregulation of renal high-capacity sodium glucose cotransporter (SGLT2) and upregulation of SGLT1; these changes appeared to be absent in the KOM. Overall, these findings suggest a sex-differential reliance on intact renal tubular InsR signaling which may be translationally important in type 2 diabetes, obesity, or insulin resistance when renal insulin signaling is reduced.
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Affiliation(s)
- Soha Sohail
- Department of Medicine, Georgetown University, Washington, DC 20057, USA
| | - Gabriella Akkawi
- Department of Medicine, Georgetown University, Washington, DC 20057, USA
| | - Taylor Rechter
- Department of Medicine, Georgetown University, Washington, DC 20057, USA
| | - Maurice B. Fluitt
- Department of Medicine, Georgetown University, Washington, DC 20057, USA
- Department of Medicine, Howard University, Washington, DC 20059, USA
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2
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The Post-Translational Modification Networking in WNK-Centric Hypertension Regulation and Electrolyte Homeostasis. Biomedicines 2022; 10:biomedicines10092169. [PMID: 36140271 PMCID: PMC9496095 DOI: 10.3390/biomedicines10092169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/26/2022] [Accepted: 08/27/2022] [Indexed: 11/17/2022] Open
Abstract
The with-no-lysine (WNK) kinase family, comprising four serine-threonine protein kinases (WNK1-4), were first linked to hypertension due to their mutations in association with pseudohypoaldosteronism type II (PHAII). WNK kinases regulate crucial blood pressure regulators, SPAK/OSR1, to mediate the post-translational modifications (PTMs) of their downstream ion channel substrates, such as sodium chloride co-transporter (NCC), epithelial sodium chloride (ENaC), renal outer medullary potassium channel (ROMK), and Na/K/2Cl co-transporters (NKCCs). In this review, we summarize the molecular pathways dysregulating the WNKs and their downstream target renal ion transporters. We summarize each of the genetic variants of WNK kinases and the small molecule inhibitors that have been discovered to regulate blood pressure via WNK-triggered PTM cascades.
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3
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Demaretz S, Seaayfan E, Bakhos-Douaihy D, Frachon N, Kömhoff M, Laghmani K. Golgi Alpha1,2-Mannosidase IA Promotes Efficient Endoplasmic Reticulum-Associated Degradation of NKCC2. Cells 2021; 11:cells11010101. [PMID: 35011665 PMCID: PMC8750359 DOI: 10.3390/cells11010101] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2021] [Revised: 12/24/2021] [Accepted: 12/27/2021] [Indexed: 12/18/2022] Open
Abstract
Mutations in the apically located kidney Na-K-2Cl cotransporter NKCC2 cause type I Bartter syndrome, a life-threatening kidney disorder. We previously showed that transport from the ER represents the limiting phase in NKCC2 journey to the cell surface. Yet very little is known about the ER quality control components specific to NKCC2 and its disease-causing mutants. Here, we report the identification of Golgi alpha1, 2-mannosidase IA (ManIA) as a novel binding partner of the immature form of NKCC2. ManIA interaction with NKCC2 takes place mainly at the cis-Golgi network. ManIA coexpression decreased total NKCC2 protein abundance whereas ManIA knock-down produced the opposite effect. Importantly, ManIA coexpression had a more profound effect on NKCC2 folding mutants. Cycloheximide chase assay showed that in cells overexpressing ManIA, NKCC2 stability and maturation are heavily hampered. Deleting the cytoplasmic region of ManIA attenuated its interaction with NKCC2 and inhibited its effect on the maturation of the cotransporter. ManIA-induced reductions in NKCC2 expression were offset by the proteasome inhibitor MG132. Likewise, kifunensine treatment greatly reduced ManIA effect, strongly suggesting that mannose trimming is involved in the enhanced ERAD of the cotransporter. Moreover, depriving ManIA of its catalytic domain fully abolished its effect on NKCC2. In summary, our data demonstrate the presence of a ManIA-mediated ERAD pathway in renal cells promoting retention and degradation of misfolded NKCC2 proteins. They suggest a model whereby Golgi ManIA contributes to ERAD of NKCC2, by promoting the retention, recycling, and ERAD of misfolded proteins that initially escape protein quality control surveillance within the ER.
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Affiliation(s)
- Sylvie Demaretz
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Elie Seaayfan
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Dalal Bakhos-Douaihy
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Nadia Frachon
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
| | - Martin Kömhoff
- Division of Pediatric Nephrology and Transplantation, University Children’s Hospital, Philipps-University, 35043 Marburg, Germany;
| | - Kamel Laghmani
- Centre de Recherche des Cordeliers, Sorbonne Université, Inserm, Université de Paris, F-75006 Paris, France; (S.D.); (E.S.); (D.B.-D.); (N.F.)
- CNRS, ERL8228, F-75006 Paris, France
- Correspondence:
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4
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Lee HJ, Mariappan MM, Norton L, Bakewell T, Feliers D, Oh SB, Donati A, Rubannelsonkumar CS, Venkatachalam MA, Harris SE, Rubera I, Tauc M, Ghosh Choudhury G, Kahn CR, Sharma K, DeFronzo RA, Kasinath BS. Proximal tubular epithelial insulin receptor mediates high-fat diet-induced kidney injury. JCI Insight 2021; 6:143619. [PMID: 33400689 PMCID: PMC7934847 DOI: 10.1172/jci.insight.143619] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 12/29/2020] [Indexed: 01/04/2023] Open
Abstract
The role of insulin receptor (IR) activated by hyperinsulinemia in obesity-induced kidney injury is not well understood. We hypothesized that activation of kidney proximal tubule epithelial IR contributes to obesity-induced kidney injury. We administered normal-fat diet (NFD) or high-fat diet (HFD) to control and kidney proximal tubule IR–knockout (KPTIRKO) mice for 4 months. Renal cortical IR expression was decreased by 60% in male and female KPTIRKO mice. Baseline serum glucose, serum creatinine, and the ratio of urinary albumin to creatinine (ACR) were similar in KPTIRKO mice compared to those of controls. On HFD, weight gain and increase in serum cholesterol were similar in control and KPTIRKO mice; blood glucose did not change. HFD increased the following parameters in the male control mice: renal cortical contents of phosphorylated IR and Akt, matrix proteins, urinary ACR, urinary kidney injury molecule-1–to-creatinine ratio, and systolic blood pressure. Renal cortical generation of hydrogen sulfide was reduced in HFD-fed male control mice. All of these parameters were ameliorated in male KPTIRKO mice. Interestingly, female mice were resistant to HFD-induced kidney injury in both genotypes. We conclude that HFD-induced kidney injury requires renal proximal tubule IR activation in male mice.
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Affiliation(s)
- Hak Joo Lee
- Center for Renal Medicine, Division of Nephrology
| | | | - Luke Norton
- Division of Diabetes, Department of Medicine
| | | | | | - Sae Byeol Oh
- Center for Renal Medicine, Division of Nephrology
| | | | | | | | - Stephen E Harris
- Department of Periodontics, University of Texas Health, San Antonio, Texas, USA
| | - Isabelle Rubera
- Universite Cote d'Azur, CNRS - UMR-7370, Laboratoire de Physiomédecine Moléculaire, Nice, France
| | - Michel Tauc
- Universite Cote d'Azur, CNRS - UMR-7370, Laboratoire de Physiomédecine Moléculaire, Nice, France
| | - Goutam Ghosh Choudhury
- Center for Renal Medicine, Division of Nephrology.,VA Research and.,Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, USA
| | - C Ronald Kahn
- Joslin Diabetes Center and Harvard Medical School, Boston, Massachusetts, USA
| | - Kumar Sharma
- Center for Renal Medicine, Division of Nephrology.,VA Research and
| | | | - Balakuntalam S Kasinath
- Center for Renal Medicine, Division of Nephrology.,VA Research and.,Geriatric Research, Education and Clinical Center, South Texas Veterans Health Care System, San Antonio, Texas, USA
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5
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Kwon YJ, Kim JO, Park JM, Choi JE, Park DH, Song Y, Kim SJ, Lee JW, Hong KW. Identification of Genetic Factors Underlying the Association between Sodium Intake Habits and Hypertension Risk. Nutrients 2020; 12:E2580. [PMID: 32854392 PMCID: PMC7551216 DOI: 10.3390/nu12092580] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/16/2020] [Accepted: 08/22/2020] [Indexed: 12/13/2022] Open
Abstract
The role of sodium in hypertension remains unresolved. Although genetic factors have a significant impact on high blood pressure, studies comparing genetic susceptibility between people with low and high sodium diets are lacking. We aimed to investigate the genetic variations related to hypertension according to sodium intake habits in a large Korean population-based study. Data for a total of 57,363 participants in the Korean Genome and Epidemiology Study Health Examination were analyzed. Sodium intake was measured by a semi-quantitative food frequency questionnaire. We classified participants according to sodium intake being less than or greater than 2 g/day. We used logistic regression to test single-marker variants for genetic association with a diagnosis of hypertension, adjusting for age, sex, body mass index, exercise, alcohol, smoking, potassium intake, principal components 1, and principal components 2. Significant associations were defined as p < 5 × 10-8. In participants whose sodium intake was greater than 2 g/day, chromosome 6 open reading frame 10 (C6orf10)-human leukocyte antigen (HLA)-DQB1 rs6913309, ring finger protein (RNF)213 rs112735431, glycosylphosphatidylinositol anchored molecule-like (GML)- cytochrome P450 family 11 subfamily B member 1(CYP11B1) rs3819496, myosin light chain 2 (MYL2)-cut like homeobox 2 (CUX2) rs12229654, and jagged1 (JAG1) rs1887320 were significantly associated with hypertension. In participants whose intake was less than 2 g/day, echinoderm microtubule-associated protein-like 6(EML6) rs67617923 was significantly associated with hypertension. Genetic susceptibility associated with hypertension differed according to sodium intake. Identifying gene variants that contribute to the dependence of hypertension on sodium intake status could make possible more individualized nutritional recommendations for preventing cardiovascular diseases.
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Affiliation(s)
- Yu-Jin Kwon
- Department of Family Medicine, Yongin Severance Hospital, Yonsei University College of Medicine, 363, Dongbaekjukjeon-daero, Giheung-gu, Yongin-si 16995, Korea;
| | - Jung Oh Kim
- Theragen Bio Co., Ltd., Suwon 16229, Korea; (J.O.K.); (J.-E.C.); (D.-H.P.); (S.-J.K.)
| | - Jae-Min Park
- Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul 06273, Korea; (J.-M.P.); (Y.S.)
| | - Ja-Eun Choi
- Theragen Bio Co., Ltd., Suwon 16229, Korea; (J.O.K.); (J.-E.C.); (D.-H.P.); (S.-J.K.)
| | - Da-Hyun Park
- Theragen Bio Co., Ltd., Suwon 16229, Korea; (J.O.K.); (J.-E.C.); (D.-H.P.); (S.-J.K.)
| | - Youhyun Song
- Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul 06273, Korea; (J.-M.P.); (Y.S.)
| | - Seong-Jin Kim
- Theragen Bio Co., Ltd., Suwon 16229, Korea; (J.O.K.); (J.-E.C.); (D.-H.P.); (S.-J.K.)
| | - Ji-Won Lee
- Department of Family Medicine, Gangnam Severance Hospital, Yonsei University College of Medicine, 211 Eonju-ro, Gangnam-gu, Seoul 06273, Korea; (J.-M.P.); (Y.S.)
| | - Kyung-Won Hong
- Theragen Bio Co., Ltd., Suwon 16229, Korea; (J.O.K.); (J.-E.C.); (D.-H.P.); (S.-J.K.)
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6
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Nelson ME, Parker BL, Burchfield JG, Hoffman NJ, Needham EJ, Cooke KC, Naim T, Sylow L, Ling NXY, Francis D, Norris DM, Chaudhuri R, Oakhill JS, Richter EA, Lynch GS, Stöckli J, James DE. Phosphoproteomics reveals conserved exercise-stimulated signaling and AMPK regulation of store-operated calcium entry. EMBO J 2019; 38:e102578. [PMID: 31381180 PMCID: PMC6912027 DOI: 10.15252/embj.2019102578] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 06/27/2019] [Accepted: 07/01/2019] [Indexed: 12/20/2022] Open
Abstract
Exercise stimulates cellular and physiological adaptations that are associated with widespread health benefits. To uncover conserved protein phosphorylation events underlying this adaptive response, we performed mass spectrometry-based phosphoproteomic analyses of skeletal muscle from two widely used rodent models: treadmill running in mice and in situ muscle contraction in rats. We overlaid these phosphoproteomic signatures with cycling in humans to identify common cross-species phosphosite responses, as well as unique model-specific regulation. We identified > 22,000 phosphosites, revealing orthologous protein phosphorylation and overlapping signaling pathways regulated by exercise. This included two conserved phosphosites on stromal interaction molecule 1 (STIM1), which we validate as AMPK substrates. Furthermore, we demonstrate that AMPK-mediated phosphorylation of STIM1 negatively regulates store-operated calcium entry, and this is beneficial for exercise in Drosophila. This integrated cross-species resource of exercise-regulated signaling in human, mouse, and rat skeletal muscle has uncovered conserved networks and unraveled crosstalk between AMPK and intracellular calcium flux.
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Affiliation(s)
- Marin E Nelson
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Benjamin L Parker
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
- Present address:
Department of PhysiologyThe University of MelbourneMelbourneVic.Australia
| | - James G Burchfield
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Nolan J Hoffman
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
- Present address:
Exercise and Nutrition Research ProgramMary MacKillop Institute for Health ResearchAustralian Catholic UniversityMelbourneVic.Australia
| | - Elise J Needham
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Kristen C Cooke
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Timur Naim
- Centre for Muscle ResearchDepartment of PhysiologySchool of Biomedical SciencesThe University of MelbourneMelbourneVicAustralia
| | - Lykke Sylow
- Department of Nutrition, Exercise and SportsFaculty of ScienceThe University of CopenhagenCopenhagenDenmark
| | - Naomi XY Ling
- Metabolic Signalling LaboratorySt. Vincent's Institute of Medical ResearchMelbourneVic.Australia
| | - Deanne Francis
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Dougall M Norris
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Rima Chaudhuri
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - Jonathan S Oakhill
- Metabolic Signalling LaboratorySt. Vincent's Institute of Medical ResearchMelbourneVic.Australia
- Exercise and Nutrition Research ProgramMary MacKillop Institute for Health ResearchAustralian Catholic UniversityMelbourneVic.Australia
| | - Erik A Richter
- Department of Nutrition, Exercise and SportsFaculty of ScienceThe University of CopenhagenCopenhagenDenmark
| | - Gordon S Lynch
- Centre for Muscle ResearchDepartment of PhysiologySchool of Biomedical SciencesThe University of MelbourneMelbourneVicAustralia
| | - Jacqueline Stöckli
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
| | - David E James
- Charles Perkins CentreSchool of Life and Environmental SciencesSydney Medical SchoolThe University of SydneySydneyNSWAustralia
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7
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King SJ, Bunz M, Chappell A, Scharl M, Docherty M, Jung B, Lytle C, McCole DF. AMPK mediates inhibition of electrolyte transport and NKCC1 activity by reactive oxygen species. Am J Physiol Gastrointest Liver Physiol 2019; 317:G171-G181. [PMID: 31070932 PMCID: PMC6734373 DOI: 10.1152/ajpgi.00317.2018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Reactive oxygen species such as H2O2 are believed to play a prominent role in the injury and loss of transport function that affect the intestinal epithelium in inflammatory conditions such as inflammatory bowel diseases. Defects in intestinal epithelial ion transport regulation contribute to dysbiosis and inflammatory phenotypes. We previously showed that H2O2 inhibits Ca2+-dependent Cl- secretion across intestinal epithelial cells (IECs) via a phosphatidylinositol 3-kinase (PI3K)- and extracellular signal-regulated kinase (ERK)-dependent mechanism that occurs, at least in part, through inhibition of the basolateral Na+-K+-2Cl- cotransporter NKCC1. NKCC1 governs Cl- entry into crypt IECs and thus plays a critical role in maintaining the driving force for Cl- secretion. Electrolyte transport consumes large amounts of cellular energy, and direct pharmacological activation of the cellular energy sensor AMP-activated protein kinase (AMPK) has been shown to inhibit a number of ion transport proteins. Here, we show that H2O2 activates AMPK in human IEC lines and ex vivo human colon. Moreover, we demonstrate that the inhibitory effect of H2O2 on Ca2+-dependent Cl- secretion and NKCC1 activity is AMPK-dependent. This inhibitory effect is associated with a physical interaction between AMPK and NKCC1, as well as increased phosphorylation (Thr212,217) of NKCC1, without causing NKCC1 internalization. These data identify a key role for AMPK-NKCC1 interaction as a point of convergence for suppression of colonic epithelial ion transport by inflammatory reactive oxygen species.NEW & NOTEWORTHY H2O2 inhibition of intestinal epithelial Ca2+-dependent Cl- secretion involves recruitment of AMP-activated protein kinase (AMPK) downstream of ERK and phosphatidylinositol 3-kinase signaling pathways, physical interaction of AMPK with the Na+-K+-2Cl- cotransporter NKCC1, and AMPK-dependent suppression of NKCC1-mediated electrolyte influx without causing NKCC1 internalization. It is intriguing that, in human intestinal epithelial cell lines and human colon, H2O2 activation of AMPK increased phosphorylation of NKCC1 residues required for promoting, not inhibiting, NKCC1 activity. These data identify an elevated complexity of AMPK regulation of NKCC1 in the setting of an inflammatory stimulus.
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Affiliation(s)
- Stephanie J. King
- 1Division of Biomedical Sciences, University of California, Riverside, Riverside, California
| | - Michael Bunz
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California,3Kreisklinik Woert an der Donau, Department of Anaesthesiology and Intensive Care Medicine, Woerth an der Donau, Germany
| | - Alfred Chappell
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California
| | - Michael Scharl
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California,4Division of Gastroenterology and Hepatology, Zurich Center for Integrative Human Physiology, University Hospital and University of Zurich, Zurich, Switzerland
| | - Michael Docherty
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California
| | - Barbara Jung
- 2Division of Gastroenterology, School of Medicine, University of California, San Diego, La Jolla, California
| | - Christian Lytle
- 1Division of Biomedical Sciences, University of California, Riverside, Riverside, California
| | - Declan F. McCole
- 1Division of Biomedical Sciences, University of California, Riverside, Riverside, California
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8
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Choy SW, Fraser SA, Katerelos M, Galic S, Kemp BE, Mount PF, Power DA. Absence of the β1 subunit of AMP-activated protein kinase reduces myofibroblast infiltration of the kidneys in early diabetes. Int J Exp Pathol 2019; 100:114-122. [PMID: 31025787 DOI: 10.1111/iep.12313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2018] [Revised: 02/21/2019] [Accepted: 02/24/2019] [Indexed: 01/23/2023] Open
Abstract
Activation of the heterotrimeric energy-sensing kinase AMP-activated protein kinase (AMPK) has been reported to improve experimental diabetic kidney disease. We examined the effect of type 1 diabetes in wild-type (WT) mice and mice lacking the β1 subunit of AMPK (AMPK β1-/- mice), which have reduced AMPK activity in kidneys and other organs. Diabetes was induced using streptozotocin (STZ) and the animals followed up for 4 weeks. Hyperglycaemia was more severe in diabetic AMPK β1-/- mice, despite the absence of any difference in serum levels of insulin, adiponectin and leptin. There was no change in AMPK activity in the kidneys of diabetic WT mice by AMPK activity assay, or phosphorylation of either the αT172 activation site on the α catalytic subunit of AMPK or the AMPK-specific phosphosite S79 on acetyl CoA carboxylase 1 (ACC1). Phosphorylation of the inhibitory αS485 site on the α subunit of AMPK was significantly increased in the WT diabetic mice compared to non-diabetic controls. Despite increased plasma glucose levels in the diabetic AMPK β1-/- mice, there were fewer myofibroblasts in the kidneys compared to diabetic WT mice, as evidenced by reduced α-smooth muscle actin (α-SMA) protein by Western blot, mRNA by qRT-PCR and fewer α-SMA-positive cells by immunohistochemical staining. Albuminuria was also reduced in the AMPK β1-/- mice. In contrast to previous studies, therefore, myofibroblasts were reduced in the kidneys of AMPK β1-/- diabetic mice compared to diabetic WT mice, despite increased circulating glucose, suggesting that AMPK can worsen renal fibrosis in type 1 diabetes.
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Affiliation(s)
- Suet-Wan Choy
- Kidney Laboratory, Institute for Breathing and Sleep, University of Melbourne, Heidelberg, Victoria, Australia.,Department of Nephrology, University of Melbourne, Heidelberg, Victoria, Australia.,Department of Medicine, University of Melbourne, Austin Health and St. Vincent's Hospital, Heidelberg, Victoria, Australia
| | - Scott A Fraser
- Kidney Laboratory, Institute for Breathing and Sleep, University of Melbourne, Heidelberg, Victoria, Australia
| | - Marina Katerelos
- Kidney Laboratory, Institute for Breathing and Sleep, University of Melbourne, Heidelberg, Victoria, Australia
| | - Sandra Galic
- St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia
| | - Bruce E Kemp
- Department of Medicine, University of Melbourne, Austin Health and St. Vincent's Hospital, Heidelberg, Victoria, Australia.,St. Vincent's Institute of Medical Research, Fitzroy, Victoria, Australia.,Mary MacKillop Institute for Health Research, Australian Catholic University, Fitzroy, VIC, Australia
| | - Peter F Mount
- Kidney Laboratory, Institute for Breathing and Sleep, University of Melbourne, Heidelberg, Victoria, Australia.,Department of Nephrology, University of Melbourne, Heidelberg, Victoria, Australia.,Department of Medicine, University of Melbourne, Austin Health and St. Vincent's Hospital, Heidelberg, Victoria, Australia
| | - David A Power
- Kidney Laboratory, Institute for Breathing and Sleep, University of Melbourne, Heidelberg, Victoria, Australia.,Department of Nephrology, University of Melbourne, Heidelberg, Victoria, Australia.,Department of Medicine, University of Melbourne, Austin Health and St. Vincent's Hospital, Heidelberg, Victoria, Australia
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9
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Hu CC, Katerelos M, Choy SW, Crossthwaite A, Walker SP, Pell G, Lee M, Cook N, Mount PF, Paizis K, Power DA. Pre-eclampsia is associated with altered expression of the renal sodium transporters NKCC2, NCC and ENaC in urinary extracellular vesicles. PLoS One 2018; 13:e0204514. [PMID: 30248150 PMCID: PMC6152984 DOI: 10.1371/journal.pone.0204514] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2018] [Accepted: 09/10/2018] [Indexed: 01/01/2023] Open
Abstract
Pre-eclampsia is a hypertensive disorder of pregnancy characterised by hypertension and sodium retention by the kidneys. To identify changes in sodium uptake proteins in the tubules of the distal nephron, we studied their expression in urinary extracellular vesicles or exosomes (uEVs). Urine was collected from women with pre-eclampsia or during normal pregnancy, and from healthy non-pregnant controls. uEVs were isolated by centrifugation and analyzed by Western blot. Expression, proteolytic cleavage and phosphorylation was determined by densitometric analysis normalized to the exosome marker CD9. Results showed a significant increase in phosphorylation of the activating S130 site in NKCC2, the drug target for frusemide, in women with pre-eclampsia compared with normal pregnant women. Phosphorylation of the activating sites T101/105 in NKCC2 was similar but the activating T60 site in NCC, the drug target for thiazide diuretics, showed significantly less phosphorylation in pre-eclampsia compared with normal pregnancy. Expression of the larger forms of the α subunit of ENaC, the drug target for amiloride, was significantly greater in pre-eclampsia, with more fragmentation of theγ subunit. The differences observed are predicted to increase the activity of NKCC2 and ENaC while reducing that of NCC. This will increase sodium reabsorption, and so contribute to hypertension in pre-eclampsia.
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Affiliation(s)
- Chih-Chiang Hu
- Melbourne Medical School, University of Melbourne, Parkville, Victoria, Australia
| | - Marina Katerelos
- Kidney Laboratory, Institute for Breathing and Sleep (IBAS), Austin Health, Heidelberg, Victoria Australia
| | - Suet-Wan Choy
- Department of Nephrology, Austin Health, Heidelberg, Victoria, Australia
- Mercy Hospital for Women, Heidelberg, Victoria, Australia
| | - Amy Crossthwaite
- Department of Nephrology, Austin Health, Heidelberg, Victoria, Australia
- Mercy Hospital for Women, Heidelberg, Victoria, Australia
- Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Susan P. Walker
- Melbourne Medical School, University of Melbourne, Parkville, Victoria, Australia
- Mercy Hospital for Women, Heidelberg, Victoria, Australia
| | - Gabrielle Pell
- Mercy Hospital for Women, Heidelberg, Victoria, Australia
| | - Mardiana Lee
- Department of Nephrology, Austin Health, Heidelberg, Victoria, Australia
- Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Natasha Cook
- Obstetrics and Gynecology, University of Melbourne, Parkville, Victoria, Australia
| | - Peter F. Mount
- Kidney Laboratory, Institute for Breathing and Sleep (IBAS), Austin Health, Heidelberg, Victoria Australia
- Department of Nephrology, Austin Health, Heidelberg, Victoria, Australia
- Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
| | - Kathy Paizis
- Department of Nephrology, Austin Health, Heidelberg, Victoria, Australia
- Mercy Hospital for Women, Heidelberg, Victoria, Australia
| | - David A. Power
- Kidney Laboratory, Institute for Breathing and Sleep (IBAS), Austin Health, Heidelberg, Victoria Australia
- Department of Nephrology, Austin Health, Heidelberg, Victoria, Australia
- Department of Medicine, University of Melbourne, Parkville, Victoria, Australia
- * E-mail:
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10
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(Pro)Renin receptor mediates obesity-induced antinatriuresis and elevated blood pressure via upregulation of the renal epithelial sodium channel. PLoS One 2018; 13:e0202419. [PMID: 30118514 PMCID: PMC6097690 DOI: 10.1371/journal.pone.0202419] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Accepted: 07/10/2018] [Indexed: 11/21/2022] Open
Abstract
Recent studies have demonstrated that the renal (pro)renin receptor (PRR) regulates expression of the alpha subunit of the epithelial sodium channel (α-ENaC). In this study we hypothesized that the renal PRR mediates high fat diet (HFD)-induced sodium retention and elevated systolic blood pressure (SBP) by enhancing expression of the epithelial sodium channel (α-ENaC). In our study we used a recently developed inducible nephron specific PRR knockout mouse. Mice (n = 6 each group) were allocated to receive regular diet (RD, 12 kcal% fat) or a high-fat diet (HFD, 45 kcal% fat) for 10 weeks. Body weight (BW), SBP, urine volume (UV) and urine sodium (UNaV), as well as renal interstitial Angiotensin II (Ang II), and renal medullary expression of PRR, p-SGK-1, α-ENaC were monitored in RD and HFD mice with or without PRR knockout. At baseline, there were no significant differences in BW, BP, UV or UNaV between different animal groups. At the end of the study, HFD mice had significant increases in SBP, BW, and significant reductions in UV and UNaV. Compared to RD, HFD significantly increased mRNA and protein expression of PRR, α-ENaC, p-SGK-1, and Ang II. Compared to HFD alone, PRR knockout mice on HFD had reduced mRNA and protein expression of PRR, p-SGK-1, and α-ENaC, as well as increased UV, UNaV and significantly reduced SBP. RIF Ang II was significantly increased by HFD and did not change in response to PRR knockout. We conclude that obesity induced sodium retention and elevated SBP are mediated by the PRR-SGK-1- α-ENaC pathway independent of Ang II.
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11
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Trafficking and regulation of the NKCC2 cotransporter in the thick ascending limb. Curr Opin Nephrol Hypertens 2018; 26:392-397. [PMID: 28614115 DOI: 10.1097/mnh.0000000000000351] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
PURPOSE OF REVIEW The kidney Na-K-2Cl cotransporter (NKCC2) is essential for urinary concentration and renal electrolyte handling. Loss of function mutations in the NKCC2 gene cause urinary salt and potassium wasting, whereas excessive NKCC2 function has been linked to high blood pressure. Loop diuretics, targeting the transporter, are instrumental for relieving edema or hypertension. This review focuses on intrinsic mechanisms regulating NKCC2 activity at the posttranslational level, namely its trafficking and phosphorylation. RECENT FINDINGS Protein networks mediating cellular turnover of NKCC2 have recently received major attention. Several key components of its apical trafficking were identified, including respective chaperones, SNARE protein family members and raft-associated proteins. NKCC2 internalization has been characterized qualitatively and quantitatively. Kinase and phosphatase pathways regulating NKCC2 activity have been clarified and links between NKCC2 phosphorylation and trafficking proposed. Constitutive and inducible NKCC2 trafficking and phosphorylation mechanisms have been specified with focus on endocrine control of thick ascending limb (TAL) function by vasopressin. SUMMARY Proper NKCC2 trafficking and phosphorylation are critical to the TAL function in the physiological context of urinary concentration and extracellular volume regulation. Clarification of the underlying mechanisms and respective protein networks may open new therapeutic perspectives for better management of renal electrolyte disorders and blood pressure control.
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12
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Abstract
The metabolic syndrome describes a clustering of risk factors—visceral obesity, dyslipidaemia, insulin resistance, and salt-sensitive hypertension—that increases mortality related to cardiovascular disease, type 2 diabetes, cancer, and non-alcoholic fatty liver disease. The prevalence of these concurrent comorbidities is ~ 25–30% worldwide, and metabolic syndrome therefore presents a significant global public health burden. Evidence from clinical and preclinical studies indicates that glucocorticoid excess is a key causal feature of metabolic syndrome. This is not increased systemic in circulating cortisol, rather increased bioavailability of active glucocorticoids within tissues. This review examines the role of covert glucocorticoid excess on the hypertension of the metabolic syndrome. Here, the role of the 11β-hydroxysteroid dehydrogenase enzymes, which exert intracrine and paracrine control over glucocorticoid signalling, is examined. 11βHSD1 amplifies glucocorticoid action in cells and contributes to hypertension through direct and indirect effects on the kidney and vasculature. The deactivation of glucocorticoid by 11βHSD2 controls ligand access to glucocorticoid and mineralocorticoid receptors: loss of function promotes salt retention and hypertension. As for hypertension in general, high blood pressure in the metabolic syndrome reflects a complex interaction between multiple systems. The clear association between high dietary salt, glucocorticoid production, and metabolic disorders has major relevance for human health and warrants systematic evaluation.
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Affiliation(s)
- Matthew A Bailey
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.
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13
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Kasper P, Vohlen C, Dinger K, Mohr J, Hucklenbruch-Rother E, Janoschek R, Köth J, Matthes J, Appel S, Dötsch J, Alejandre Alcazar MA. Renal Metabolic Programming Is Linked to the Dynamic Regulation of a Leptin-Klf15 Axis and Akt/AMPKα Signaling in Male Offspring of Obese Dams. Endocrinology 2017; 158:3399-3415. [PMID: 28938412 DOI: 10.1210/en.2017-00489] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Accepted: 07/24/2017] [Indexed: 12/27/2022]
Abstract
Childhood obesity is associated with renal diseases. Maternal obesity is a risk factor linked to increased adipocytokines and metabolic disorders in the offspring. Therefore, we studied the impact of maternal obesity on renal-intrinsic insulin and adipocytokine signaling and on renal function and structure. To induce maternal obesity, female mice were fed a high-fat diet (HFD) or a standard diet (SD; control group) prior to mating, during gestation, and throughout lactation. A third group of dams was fed HFD only during lactation (HFD-Lac). After weaning at postnatal day (P)21, offspring of all groups received SD. Clinically, HFD offspring were overweight and insulin resistant at P21. Although no metabolic changes were detected at P70, renal sodium excretion was reduced by 40%, and renal matrix deposition increased in the HFD group. Mechanistically, two stages were differentiated. In the early stage (P21), compared with the control group, HFD showed threefold increased white adipose tissue, impaired glucose tolerance, hyperleptinemia, and hyperinsulinemia. Renal leptin/Stat3-signaling was activated. In contrast, the Akt/ AMPKα cascade and Krüppel-like factor 15 expression were decreased. In the late stage (P70), although no metabolic differences were detected in HFD when compared with the control group, leptin/Stat3-signaling was reduced, and Akt/AMPKα was activated in the kidneys. This effect was linked to an increase of proliferative (cyclinD1/D2) and profibrotic (ctgf/collagen IIIα1) markers, similar to leptin-deficient mice. HFD-Lac mice exhibited metabolic changes at P21 similar to HFD, but no other persistent changes. This study shows a link between maternal obesity and metabolic programming of renal structure and function and intrinsic-renal Stat3/Akt/AMPKα signaling in the offspring.
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Affiliation(s)
- Philipp Kasper
- Translational Experimental Pediatrics, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Christina Vohlen
- Translational Experimental Pediatrics, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- Metabolism and Perinatal Programming, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Katharina Dinger
- Translational Experimental Pediatrics, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Jasmine Mohr
- Translational Experimental Pediatrics, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Eva Hucklenbruch-Rother
- Metabolism and Perinatal Programming, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Ruth Janoschek
- Metabolism and Perinatal Programming, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Jessica Köth
- Department of Pharmacology, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Jan Matthes
- Department of Pharmacology, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Sarah Appel
- University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Jörg Dötsch
- University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
| | - Miguel A Alejandre Alcazar
- Translational Experimental Pediatrics, University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
- University Hospital for Pediatrics and Adolescent Medicine, Faculty of Medicine, University of Cologne, 50937 Cologne, Germany
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14
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The autophagy initiator ULK1 sensitizes AMPK to allosteric drugs. Nat Commun 2017; 8:571. [PMID: 28924239 PMCID: PMC5603566 DOI: 10.1038/s41467-017-00628-y] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 07/14/2017] [Indexed: 01/10/2023] Open
Abstract
AMP-activated protein kinase (AMPK) is a metabolic stress-sensing enzyme responsible for maintaining cellular energy homeostasis. Activation of AMPK by salicylate and the thienopyridone A-769662 is critically dependent on phosphorylation of Ser108 in the β1 regulatory subunit. Here, we show a possible role for Ser108 phosphorylation in cell cycle regulation and promotion of pro-survival pathways in response to energy stress. We identify the autophagy initiator Unc-51-like kinase 1 (ULK1) as a β1-Ser108 kinase in cells. Cellular β1-Ser108 phosphorylation by ULK1 was dependent on AMPK β-subunit myristoylation, metabolic stress associated with elevated AMP/ATP ratio, and the intrinsic energy sensing capacity of AMPK; features consistent with an AMP-induced myristoyl switch mechanism. We further demonstrate cellular AMPK signaling independent of activation loop Thr172 phosphorylation, providing potential insight into physiological roles for Ser108 phosphorylation. These findings uncover new mechanisms by which AMPK could potentially maintain cellular energy homeostasis independently of Thr172 phosphorylation. AMPK is involved in sensing of metabolic stress. The authors show that the autophagy initiator ULK1 phosphorylates β1-Ser108 on the regulatory β1-subunit, sensitizing AMPK to allosteric drugs, and activates signaling pathways that appear independent of Thr172 phosphorylation in the kinase activation loop.
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15
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Role of AMP-activated protein kinase in kidney tubular transport, metabolism, and disease. Curr Opin Nephrol Hypertens 2017; 26:375-383. [DOI: 10.1097/mnh.0000000000000349] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
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16
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Cheng CJ, Rodan AR, Huang CL. Emerging Targets of Diuretic Therapy. Clin Pharmacol Ther 2017; 102:420-435. [PMID: 28560800 DOI: 10.1002/cpt.754] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 05/15/2017] [Accepted: 05/21/2017] [Indexed: 12/14/2022]
Abstract
Diuretics are commonly prescribed for treatment in patients with hypertension, edema, or heart failure. Studies on hypertensive and salt-losing disorders and on urea transporters have contributed to better understanding of mechanisms of renal salt and water reabsorption and their regulation. Proteins involved in the regulatory pathways are emerging targets for diuretic and aquaretic therapy. Integrative high-throughput screening, protein structure analysis, and chemical modification have identified promising agents for preclinical testing in animals. These include WNK-SPAK inhibitors, ClC-K channel antagonists, ROMK channel antagonists, and pendrin and urea transporter inhibitors. We discuss the potential advantages and side effects of these potential diuretics.
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Affiliation(s)
- C-J Cheng
- Department of Medicine, Division of Nephrology, Tri-Service General Hospital, National Defense Medical Center, Taipei, 114, Taiwan
| | - A R Rodan
- Department of Medicine, Division of Nephrology, University of Utah, Salt Lake City, Utah, USA
| | - C-L Huang
- Department of Medicine, Division of Nephrology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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17
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Molecular Mechanisms of Sodium-Sensitive Hypertension in the Metabolic Syndrome. Curr Hypertens Rep 2017; 19:60. [DOI: 10.1007/s11906-017-0759-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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18
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Duan Q, Song P, Ding Y, Zou MH. Activation of AMP-activated protein kinase by metformin ablates angiotensin II-induced endoplasmic reticulum stress and hypertension in mice in vivo. Br J Pharmacol 2017; 174:2140-2151. [PMID: 28436023 DOI: 10.1111/bph.13833] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 03/29/2017] [Accepted: 04/16/2017] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND AND PURPOSE Metformin, one of the most frequently prescribed medications for type 2 diabetes, reportedly exerts BP-lowering effects in patients with diabetes. However, the effects and underlying mechanisms of metformin on BP in non-diabetic conditions remain to be determined. The aim of the present study was to determine the effects of metformin on angiotensin II (Ang II) infusion-induced hypertension in vivo. EXPERIMENTAL APPROACH The effects of metformin on BP were investigated in wild-type (WT) C57BL/6J mice and in mice lacking AMP-activated protein kinase α2 (AMPKα2) mice with or without Ang II infusion. Also, the effect of metformin on Ang II-induced endoplasmic reticulum (ER) stress was explored in cultured human vascular smooth muscle cells (hVSMCs). KEY RESULTS Metformin markedly reduced BP in Ang II-infused WT mice but not in AMPKα2-deficient mice. In cultured hVSMCs, Ang II treatment resulted in inactivation of AMPK, as well as the subsequent induction of spliced X-box binding protein-1, phosphorylation of eukaryotic translation initiation factor 2α and expression of glucose-regulated protein 78 kDa, representing three well-characterized ER stress biomarkers. Moreover, AMPK activation by metformin ablated Ang II-induced ER stress in hVSMCs. Mechanistically, metformin-activated AMPKα2 suppressed ER stress by increasing phospholamban phosphorylation. CONCLUSION AND IMPLICATIONS Metformin alleviates Ang II-triggered hypertension in mice by activating AMPKα2, which mediates phospholamban phosphorylation and inhibits Ang II-induced ER stress in vascular smooth muscle cells.
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Affiliation(s)
- Quanlu Duan
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA.,Division of Cardiology, Department Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Ping Song
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA
| | - Ye Ding
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA
| | - Ming-Hui Zou
- Center for Molecular and Translational Medicine, Georgia State University, Atlanta, GA, USA
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19
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Raider K, Ma D, Harris JL, Fuentes I, Rogers RS, Wheatley JL, Geiger PC, Yeh HW, Choi IY, Brooks WM, Stanford JA. A high fat diet alters metabolic and bioenergetic function in the brain: A magnetic resonance spectroscopy study. Neurochem Int 2016; 97:172-80. [PMID: 27125544 PMCID: PMC4900919 DOI: 10.1016/j.neuint.2016.04.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 04/18/2016] [Accepted: 04/20/2016] [Indexed: 11/18/2022]
Abstract
Diet-induced obesity and associated metabolic effects can lead to neurological dysfunction and increase the risk of developing Alzheimer's disease (AD) and Parkinson's disease (PD). Despite these risks, the effects of a high-fat diet on the central nervous system are not well understood. To better understand the mechanisms underlying the effects of high fat consumption on brain regions affected by AD and PD, we used proton magnetic resonance spectroscopy ((1)H-MRS) to measure neurochemicals in the hippocampus and striatum of rats fed a high fat diet vs. normal low fat chow. We detected lower concentrations of total creatine (tCr) and a lower glutamate-to-glutamine ratio in the hippocampus of high fat rats. Additional effects observed in the hippocampus of high fat rats included higher N-acetylaspartylglutamic acid (NAAG), and lower myo-inositol (mIns) and serine (Ser) concentrations. Post-mortem tissue analyses revealed lower phosphorylated AMP-activated protein kinase (pAMPK) in the striatum but not in the hippocampus of high fat rats. Hippocampal pAMPK levels correlated significantly with tCr, aspartate (Asp), phosphoethanolamine (PE), and taurine (Tau), indicating beneficial effects of AMPK activation on brain metabolic and energetic function, membrane turnover, and edema. A negative correlation between pAMPK and glucose (Glc) indicates a detrimental effect of brain Glc on cellular energy response. Overall, these changes indicate alterations in neurotransmission and in metabolic and bioenergetic function in the hippocampus and in the striatum of rats fed a high fat diet.
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Affiliation(s)
- Kayla Raider
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Delin Ma
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Janna L Harris
- Department of Anatomy & Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Isabella Fuentes
- Department of Anatomy & Cell Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Robert S Rogers
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Joshua L Wheatley
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Paige C Geiger
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Hung-Wen Yeh
- Department of Biostatistics, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - In-Young Choi
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - William M Brooks
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA; Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA; University of Kansas Alzheimer's Disease Center, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - John A Stanford
- Department of Molecular & Integrative Physiology, University of Kansas Medical Center, Kansas City, KS 66160, USA; Kansas Intellectual and Developmental Disabilities Research Center, University of Kansas Medical Center, Kansas City, KS 66160, USA.
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20
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Abstract
PURPOSE OF REVIEW Transepithelial salt transport in the thick ascending limb of Henle's loop (TAL) crucially depends on the activity of the Na/K/2Cl cotransporter NKCC2. The pharmacologic blockade of NKCC2 leads to pronounced natriuresis and diuresis, which indicate key roles for NKCC2 in renal salt retrieval. The inadequate regulation of NKCC2 and the loss of NKCC2 function are associated with the disruption of salt and water homoeostasis. This review provides a specific overview of our current knowledge with respect to the regulation of NKCC2 by differential splicing and phosphorylation. RECENT FINDINGS Several mechanisms have evolved to adapt NKCC2 transport to reabsorptive needs. These mechanisms include the regulation of NKCC2 gene expression, the differential splicing of the NKCC2 pre-mRNA, the membrane trafficking, and the modulation of the specific transport activity. Substantial progress has been made over the past few years in deciphering the function of kinases in the regulatory network controlling NKCC2 activity and in elucidating the underlying mechanism and the functional consequences of the regulated differential splicing of the NKCC2 pre-mRNA. SUMMARY NKCC2 differential splicing and phosphorylation are critically involved in the modulation of the thick ascending limb of Henle's loop reabsorptive capacity and, consequently, in salt homoeostasis, volume regulation, and blood pressure control.
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21
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Caffeine intake antagonizes salt sensitive hypertension through improvement of renal sodium handling. Sci Rep 2016; 6:25746. [PMID: 27173481 PMCID: PMC4866033 DOI: 10.1038/srep25746] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/15/2016] [Indexed: 01/05/2023] Open
Abstract
High salt intake is a major risk factor for hypertension. Although acute caffeine intake produces moderate diuresis and natriuresis, caffeine increases the blood pressure (BP) through activating sympathetic activity. However, the long-term effects of caffeine on urinary sodium excretion and blood pressure are rarely investigated. Here, we investigated whether chronic caffeine administration antagonizes salt sensitive hypertension by promoting urinary sodium excretion. Dahl salt-sensitive (Dahl-S) rats were fed with high salt diet with or without 0.1% caffeine in drinking water for 15 days. The BP, heart rate and locomotor activity of rats was analyzed and urinary sodium excretion was determined. The renal epithelial Na+ channel (ENaC) expression and function were measured by in vivo and in vitro experiments. Chronic consumption of caffeine attenuates hypertension induced by high salt without affecting sympathetic nerve activity in Dahl-S rats. The renal α-ENaC expression and ENaC activity of rats decreased after chronic caffeine administration. Caffeine increased phosphorylation of AMPK and decrease α-ENaC expression in cortical collecting duct cells. Inhibiting AMPK abolished the effect of caffeine on α-ENaC. Chronic caffeine intake prevented the development of salt-sensitive hypertension through promoting urinary sodium excretion, which was associated with activation of renal AMPK and inhibition of renal tubular ENaC.
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22
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Nizar JM, Dong W, McClellan RB, Labarca M, Zhou Y, Wong J, Goens DG, Zhao M, Velarde N, Bernstein D, Pellizzon M, Satlin LM, Bhalla V. Na+-sensitive elevation in blood pressure is ENaC independent in diet-induced obesity and insulin resistance. Am J Physiol Renal Physiol 2016; 310:F812-20. [PMID: 26841823 PMCID: PMC4867314 DOI: 10.1152/ajprenal.00265.2015] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 01/28/2016] [Indexed: 02/08/2023] Open
Abstract
The majority of patients with obesity, insulin resistance, and metabolic syndrome have hypertension, but the mechanisms of hypertension are poorly understood. In these patients, impaired sodium excretion is critical for the genesis of Na(+)-sensitive hypertension, and prior studies have proposed a role for the epithelial Na(+) channel (ENaC) in this syndrome. We characterized high fat-fed mice as a model in which to study the contribution of ENaC-mediated Na(+) reabsorption in obesity and insulin resistance. High fat-fed mice demonstrated impaired Na(+) excretion and elevated blood pressure, which was significantly higher on a high-Na(+) diet compared with low fat-fed control mice. However, high fat-fed mice had no increase in ENaC activity as measured by Na(+) transport across microperfused cortical collecting ducts, electrolyte excretion, or blood pressure. In addition, we found no difference in endogenous urinary aldosterone excretion between groups on a normal or high-Na(+) diet. High fat-fed mice provide a model of metabolic syndrome, recapitulating obesity, insulin resistance, impaired natriuresis, and a Na(+)-sensitive elevation in blood pressure. Surprisingly, in contrast to previous studies, our data demonstrate that high fat feeding of mice impairs natriuresis and produces elevated blood pressure that is independent of ENaC activity and likely caused by increased Na(+) reabsorption upstream of the aldosterone-sensitive distal nephron.
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Affiliation(s)
- Jonathan M Nizar
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California
| | - Wuxing Dong
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California
| | - Robert B McClellan
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California
| | - Mariana Labarca
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California
| | - Yuehan Zhou
- Division of Pediatric Nephrology, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jared Wong
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California
| | - Donald G Goens
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California
| | - Mingming Zhao
- Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Stanford, California; and
| | - Nona Velarde
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California
| | - Daniel Bernstein
- Division of Pediatric Cardiology, Department of Pediatrics, Stanford University, Stanford, California; and
| | | | - Lisa M Satlin
- Division of Pediatric Nephrology, Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Vivek Bhalla
- Division of Nephrology, Department of Medicine, Stanford University, Palo Alto, California;
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23
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DuBois BN, Pearson J, Mahmood T, Thornburg K, Cherala G. Furosemide Pharmacokinetics in Adult Rats become Abnormal with an Adverse Intrauterine Environment and Modulated by a Post-Weaning High-Fat Diet. Basic Clin Pharmacol Toxicol 2015; 118:432-9. [PMID: 26550796 DOI: 10.1111/bcpt.12523] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 10/29/2015] [Indexed: 11/27/2022]
Abstract
Adult individuals born with intrauterine growth restriction (IUGR) have physiological maladaptations that significantly increase risk of chronic disease. We suggested that such abnormalities in organ function would alter pharmacokinetics throughout life, exacerbated by environmental mismatch. Pregnant and lactating rats were fed either a purified control diet (18% protein) or low-protein diet (9% protein) to produce IUGR offspring. Offspring were weaned onto either laboratory chow (11% fat) or high-fat diet (45% fat). Adult offspring (5 months old) were dosed with furosemide (10 mg/kg i.p.) and serum and urine collected. The overall exposure profile in IUGR males was significantly reduced due to a ~35% increase in both clearance and volume of distribution. Females appeared resistant to the IUGR phenotype. The effects of the high-fat diet trended in the opposite direction to that of IUGR, with increased drug exposure due to decreases in both clearance (31% males, 46% females) and volume of distribution (24% males, 44% females), with a 10% longer half-life in both genders. The alterations in furosemide pharmacokinetics and pharmacodynamics were explained by changes in the expression of renal organic anion transporters 1 and 3, and sodium-potassium-chloride cotransporter-2. In summary, this study suggests that IUGR and diet interact to produce subpopulations with similar body-weights but dissimilar pharmacokinetic profiles; this underlines the limitation of one-size-fits-all dosing which does not account for physiological differences in body composition resulting from IUGR and diet.
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Affiliation(s)
- Barent N DuBois
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, Portland, OR, USA
| | - Jacob Pearson
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, Portland, OR, USA
| | - Tahir Mahmood
- Department of Pharmacy Practice, College of Pharmacy, Oregon State University/Oregon Health & Science University, Portland, OR, USA
| | - Kent Thornburg
- Center for Developmental Health, Oregon Health & Science University, Portland, OR, USA
| | - Ganesh Cherala
- Center for Developmental Health, Oregon Health & Science University, Portland, OR, USA.,Department of Obstetrics & Gynecology, School of Medicine, Oregon Health & Science University, Portland, OR, USA
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Orlov SN, Koltsova SV, Kapilevich LV, Gusakova SV, Dulin NO. NKCC1 and NKCC2: The pathogenetic role of cation-chloride cotransporters in hypertension. Genes Dis 2015; 2:186-196. [PMID: 26114157 PMCID: PMC4477834 DOI: 10.1016/j.gendis.2015.02.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2014] [Accepted: 02/16/2015] [Indexed: 11/17/2022] Open
Abstract
This review summarizes the data on the functional significance of ubiquitous (NKCC1) and renal-specific (NKCC2) isoforms of electroneutral sodium, potassium and chloride cotransporters. These carriers contribute to the pathogenesis of hypertension via regulation of intracellular chloride concentration in vascular smooth muscle and neuronal cells and via sensing chloride concentration in the renal tubular fluid, respectively. Both NKCC1 and NKCC2 are inhibited by furosemide and other high-ceiling diuretics widely used for attenuation of extracellular fluid volume. However, the chronic usage of these compounds for the treatment of hypertension and other volume-expanded disorders may have diverse side-effects due to suppression of myogenic response in microcirculatory beds.
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Affiliation(s)
- Sergei N. Orlov
- Faculty of Biology, M.V. Lomonosov Moscow State University, Russia
- Тomsk State University, Russia
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Castrop H, Schießl IM. Physiology and pathophysiology of the renal Na-K-2Cl cotransporter (NKCC2). Am J Physiol Renal Physiol 2014; 307:F991-F1002. [PMID: 25186299 DOI: 10.1152/ajprenal.00432.2014] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Na-K-2Cl cotransporter (NKCC2; BSC1) is located in the apical membrane of the epithelial cells of the thick ascending limb of the loop of Henle (TAL). NKCC2 facilitates ∼20–25% of the reuptake of the total filtered NaCl load. NKCC2 is therefore one of the transport proteins with the highest overall reabsorptive capacity in the kidney. Consequently, even subtle changes in NKCC2 transport activity considerably alter the renal reabsorptive capacity for NaCl and eventually lead to perturbations of the salt and water homoeostasis. In addition to facilitating the bulk reabsorption of NaCl in the TAL, NKCC2 transport activity in the macula densa cells of the TAL constitutes the initial step of the tubular-vascular communication within the juxtaglomerular apparatus (JGA); this communications allows the TAL to modulate the preglomerular resistance of the afferent arteriole and the renin secretion from the granular cells of the JGA. This review provides an overview of our current knowledge with respect to the general functions of NKCC2, the modulation of its transport activity by different regulatory mechanisms, and new developments in the pathophysiology of NKCC2-dependent renal NaCl transport.
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Affiliation(s)
- Hayo Castrop
- Institute of Physiology, University of Regensburg, Regensburg, Germany
| | - Ina Maria Schießl
- Institute of Physiology, University of Regensburg, Regensburg, Germany
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