1
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Tang W, Wei Q. The metabolic pathway regulation in kidney injury and repair. Front Physiol 2024; 14:1344271. [PMID: 38283280 PMCID: PMC10811252 DOI: 10.3389/fphys.2023.1344271] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2023] [Accepted: 12/28/2023] [Indexed: 01/30/2024] Open
Abstract
Kidney injury and repair are accompanied by significant disruptions in metabolic pathways, leading to renal cell dysfunction and further contributing to the progression of renal pathology. This review outlines the complex involvement of various energy production pathways in glucose, lipid, amino acid, and ketone body metabolism within the kidney. We provide a comprehensive summary of the aberrant regulation of these metabolic pathways in kidney injury and repair. After acute kidney injury (AKI), there is notable mitochondrial damage and oxygen/nutrient deprivation, leading to reduced activity in glycolysis and mitochondrial bioenergetics. Additionally, disruptions occur in the pentose phosphate pathway (PPP), amino acid metabolism, and the supply of ketone bodies. The subsequent kidney repair phase is characterized by a metabolic shift toward glycolysis, along with decreased fatty acid β-oxidation and continued disturbances in amino acid metabolism. Furthermore, the impact of metabolism dysfunction on renal cell injury, regeneration, and the development of renal fibrosis is analyzed. Finally, we discuss the potential therapeutic strategies by targeting renal metabolic regulation to ameliorate kidney injury and fibrosis and promote kidney repair.
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Affiliation(s)
- Wenbin Tang
- Health Management Center, Xiangya Hospital, Central South University, Changsha, Hunan, China
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, United States
| | - Qingqing Wei
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, United States
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2
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Shi Y, Bhalla V. Kidney single-cell transcriptomes uncover SGLT2i-induced metabolic reprogramming via restoring glycolysis and fatty acid oxidation. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.31.564836. [PMID: 37961186 PMCID: PMC10634955 DOI: 10.1101/2023.10.31.564836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Approximately 40% of individuals with chronic kidney disease have type 2 diabetes mellitus, and diabetic kidney disease is the leading cause of end-stage kidney disease worldwide. Inhibitors of sodium-glucose cotransporter 2 (SGLT2) have been demonstrated to be effective in glucose control, improving cardiovascular outcomes and the progression of kidney disease. However, the protective role of SGLT2 inhibition on kidney metabolism is not fully understood. To explore these mechanisms further, we conducted analysis of publicly available single-cell RNA sequencing data of db/db mice treated with an SGLT2 inhibitor(dapagliflozin) and accompanying controls. We found that proximal tubule cells exhibited impaired glycolysis and high fatty acid oxidation in diabetes compared with control mice. SGLT2 inhibition reversed this metabolic dysfunction by reducing glycolysis and its substrate accumulation. SGLT2 inhibition also upregulates high fatty oxidation without increasing the uptake of fatty acids and elongation, along with low lipotoxicity. Surprisingly, both SGLT2(+) and SGLT2(-) cells show gene consistent changes in expression of metabolic genes, consistent with a non-cell autonomous effect of dapagliflozin treatment. This study demonstrates the protective role of SGLT2 inhibition via restoring metabolic dysfunction.
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3
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Dalga D, Verissimo T, de Seigneux S. Gluconeogenesis in the kidney: in health and in chronic kidney disease. Clin Kidney J 2023; 16:1249-1257. [PMID: 37529654 PMCID: PMC10387387 DOI: 10.1093/ckj/sfad046] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Indexed: 08/03/2023] Open
Abstract
Chronic kidney disease (CKD) is a global health issue with increasing prevalence. Despite large improvements in current therapies, slowing CKD progression remains a challenge. A better understanding of renal pathophysiology is needed to offer new therapeutic targets. The role of metabolism alterations and mitochondrial dysfunction in tubular cells is increasingly recognized in CKD progression. In proximal tubular cells, CKD progression is associated with a switch from fatty acid oxidation to glycolysis. Glucose synthesis through gluconeogenesis is one of the principal physiological functions of the kidney. Loss of tubular gluconeogenesis in a stage-dependent manner is a key feature of CKD and contributes to systemic and possibly local metabolic complications. The local consequences observed may be related to an accumulation of precursors, such as glycogen, but also to the various physiological functions of the gluconeogenesis enzymes. The basic features of metabolism in proximal tubular cells and their modifications during CKD will be reviewed. The metabolic modifications and their influence on kidney disease will be described, as well as the local and systemic consequences. Finally, therapeutic interventions will be discussed.
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Affiliation(s)
- Delal Dalga
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
| | - Thomas Verissimo
- Department of Cell Physiology and Metabolism, University of Geneva, Geneva, Switzerland
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4
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Ge M, Molina J, Kim JJ, Mallela SK, Ahmad A, Varona Santos J, Al-Ali H, Mitrofanova A, Sharma K, Fontanesi F, Merscher S, Fornoni A. Empagliflozin reduces podocyte lipotoxicity in experimental Alport syndrome. eLife 2023; 12:e83353. [PMID: 37129368 PMCID: PMC10185338 DOI: 10.7554/elife.83353] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Accepted: 04/26/2023] [Indexed: 05/03/2023] Open
Abstract
Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are anti-hyperglycemic agents that prevent glucose reabsorption in proximal tubular cells. SGLT2i improves renal outcomes in both diabetic and non-diabetic patients, indicating it may have beneficial effects beyond glycemic control. Here, we demonstrate that SGLT2i affects energy metabolism and podocyte lipotoxicity in experimental Alport syndrome (AS). In vitro, we found that the SGLT2 protein was expressed in human and mouse podocytes to a similar extent in tubular cells. Newly established immortalized podocytes from Col4a3 knockout mice (AS podocytes) accumulate lipid droplets along with increased apoptosis when compared to wild-type podocytes. Treatment with SGLT2i empagliflozin reduces lipid droplet accumulation and apoptosis in AS podocytes. Empagliflozin inhibits the utilization of glucose/pyruvate as a metabolic substrate in AS podocytes but not in AS tubular cells. In vivo, we demonstrate that empagliflozin reduces albuminuria and prolongs the survival of AS mice. Empagliflozin-treated AS mice show decreased serum blood urea nitrogen and creatinine levels in association with reduced triglyceride and cholesterol ester content in kidney cortices when compared to AS mice. Lipid accumulation in kidney cortices correlates with a decline in renal function. In summary, empagliflozin reduces podocyte lipotoxicity and improves kidney function in experimental AS in association with the energy substrates switch from glucose to fatty acids in podocytes.
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Affiliation(s)
- Mengyuan Ge
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Judith Molina
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Jin-Ju Kim
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Shamroop K Mallela
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Anis Ahmad
- Department of Radiation Oncology, University of Miami Miller School of MedicineMiamiUnited States
| | - Javier Varona Santos
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Hassan Al-Ali
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Alla Mitrofanova
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Kumar Sharma
- Center for Precision Medicine, School of Medicine, University of Texas Health San AntonioSan AntonioUnited States
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, University of MiamiMiamiUnited States
| | - Sandra Merscher
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
| | - Alessia Fornoni
- Katz Family Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of MedicineMiamiUnited States
- Peggy and Harold Katz Family Drug Discovery Center, University of Miami Miller School of MedicineMiamiUnited States
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5
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Prem PN, Chellappan DR, Kurian GA. High-fat diet-induced mitochondrial dysfunction is associated with loss of protection from ischemic preconditioning in renal ischemia reperfusion. Pflugers Arch 2023; 475:637-653. [PMID: 36867229 DOI: 10.1007/s00424-023-02799-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 02/21/2023] [Accepted: 02/21/2023] [Indexed: 03/04/2023]
Abstract
Consumption of high-fat diet (HFD) promotes mitochondrial dysfunction and the latter act as a critical factor in determining the severity of ischemia-reperfusion (IR) injury in different cell types. Ischemic preconditioning (IPC), a well-known protocol that render IR protection in kidney works via mitochondria. In the present study, we evaluated how HFD kidney with underlying mitochondrial changes respond to precondition protocol after IR induction. Wistar male rats were used in this study and were divided into two groups: SD (standard diet; n = 18) and HFD (high-fat diet; n = 18), which were further subdivided into sham, ischemia-reperfusion, and precondition groups at the end of the dietary regimen. Blood biochemistry, renal injury marker, creatinine clearance (CrCl), mitochondrial quality (fission, fusion, and phagy), mitochondrial function via ETC enzyme activities and respiration, and signalling pathway were analysed. Sixteen weeks of HFD administration to the rat deteriorated the renal mitochondrial health measured via 10% decline in mitochondrial respiration index ADP/O (in GM), reduced mitochondrial copy number (55%), biogenesis (56%), low bioenergetics potential (19% complex I + III and 15% complex II + III), increased oxidative stress, and reduced expression of mitochondrial fusion genes compared with SD rats. IR procedure in HFD rat kidney inflicted significant mitochondrial dysfunction and further deteriorated copy number along with impaired mitophagy and mitochondrial dynamics. IPC could effectively ameliorate the renal ischemia injury in normal rat but failed to provide similar kind of protection in HFD rat kidney. Even though the IR-associated mitochondrial dysfunction in both normal and HFD rats were similar, the magnitude of overall dysfunction and corresponding renal injury and compromised physiology was high in HFD rats. This observation was further confirmed via in vitro protein translation assay in isolated mitochondria from normal and HFD rat kidney that showed significantly reduction in the response ability of mitochondria in HFD. In conclusion, the deteriorated mitochondrial function and its quality along with low mitochondrial copy number and downregulation of mitochondrial dynamic gene exhibited by HFD rat kidney augments the sensitivity of renal tissue towards the IR injury which leads to the compromised protective ability by ischemic preconditioning.
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Affiliation(s)
- Priyanka N Prem
- School of Chemical and Biotechnology, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, Tamil Nadu, India
| | - David Raj Chellappan
- School of Chemical and Biotechnology, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, Tamil Nadu, India
| | - Gino A Kurian
- School of Chemical and Biotechnology, SASTRA Deemed University, Tirumalaisamudram, Thanjavur, Tamil Nadu, India. .,Vascular Biology Lab, School of Chemical and Biotechnology, SASTRA Deemed University, Thanjavur, India.
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6
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Shrivastav S, Lee H, Okamoto K, Lu H, Yoshida T, Latt KZ, Wakashin H, Dalgleish JLT, Koritzinsky EH, Xu P, Asico LD, Chung JY, Hewitt S, Gildea JJ, Felder RA, Jose PA, Rosenberg AZ, Knepper MA, Kino T, Kopp JB. HIV-1 Vpr suppresses expression of the thiazide-sensitive sodium chloride co-transporter in the distal convoluted tubule. PLoS One 2022; 17:e0273313. [PMID: 36129874 PMCID: PMC9491550 DOI: 10.1371/journal.pone.0273313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/07/2022] [Indexed: 11/19/2022] Open
Abstract
HIV-associated nephropathy (HIVAN) impairs functions of both glomeruli and tubules. Attention has been previously focused on the HIVAN glomerulopathy. Tubular injury has drawn increased attention because sodium wasting is common in hospitalized HIV/AIDS patients. We used viral protein R (Vpr)-transgenic mice to investigate the mechanisms whereby Vpr contributes to urinary sodium wasting. In phosphoenolpyruvate carboxykinase promoter-driven Vpr-transgenic mice, in situ hybridization showed that Vpr mRNA was expressed in all nephron segments, including the distal convoluted tubule. Vpr-transgenic mice, compared with wild-type littermates, markedly increased urinary sodium excretion, despite similar plasma renin activity and aldosterone levels. Kidneys from Vpr-transgenic mice also markedly reduced protein abundance of the Na+-Cl- cotransporter (NCC), while mineralocorticoid receptor (MR) protein expression level was unchanged. In African green monkey kidney cells, Vpr abrogated the aldosterone-mediated stimulation of MR transcriptional activity. Gene expression of Slc12a3 (NCC) in Vpr-transgenic mice was significantly lower compared with wild-type mice, assessed by both qRT-PCR and RNAScope in situ hybridization analysis. Chromatin immunoprecipitation assays identified multiple MR response elements (MRE), located from 5 kb upstream of the transcription start site and extending to the third exon of the SLC12A3 gene. Mutation of MRE and SP1 sites in the SLC12A3 promoter region abrogated the transcriptional responses to aldosterone and Vpr, indicating that functional MRE and SP1 are required for the SLC12A3 gene suppression in response to Vpr. Thus, Vpr attenuates MR transcriptional activity and inhibits Slc12a3 transcription in the distal convoluted tubule and contributes to salt wasting in Vpr-transgenic mice.
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Affiliation(s)
- Shashi Shrivastav
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Hewang Lee
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
- Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, United States of America
| | - Koji Okamoto
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Huiyan Lu
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Teruhiko Yoshida
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Khun Zaw Latt
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Hidefumi Wakashin
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - James L. T. Dalgleish
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Erik H. Koritzinsky
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
| | - Peng Xu
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Laureano D. Asico
- Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, United States of America
| | - Joon-Yong Chung
- Experimental Pathology Laboratory, Laboratory of Pathology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America
| | - Stephen Hewitt
- Experimental Pathology Laboratory, Laboratory of Pathology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland, United States of America
| | - John J. Gildea
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Robin A. Felder
- Department of Pathology, University of Virginia, Charlottesville, Virginia, United States of America
| | - Pedro A. Jose
- Department of Medicine, The George Washington University School of Medicine & Health Sciences, Washington, DC, United States of America
| | - Avi Z. Rosenberg
- Department of Pathology, Johns Hopkins Medical Institutions, Baltimore, Maryland, United States of America
| | - Mark A. Knepper
- Epithelial Systems Biology Laboratory, Systems Biology Center, Division of Intramural Research, NHLBI, NIH, Bethesda, Maryland, United States of America
| | - Tomoshige Kino
- Laboratory for Molecular and Genomic Endocrinology, Division of Translational Medicine, Sidra Medicine, Doha, Qatar
| | - Jeffrey B. Kopp
- Kidney Disease Section, Kidney Diseases Branch, NIDDK, NIH, Bethesda, Maryland, United States of America
- * E-mail:
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7
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Harnessing conserved signaling and metabolic pathways to enhance the maturation of functional engineered tissues. NPJ Regen Med 2022; 7:44. [PMID: 36057642 PMCID: PMC9440900 DOI: 10.1038/s41536-022-00246-3] [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: 02/22/2022] [Accepted: 08/05/2022] [Indexed: 11/08/2022] Open
Abstract
The development of induced-pluripotent stem cell (iPSC)-derived cell types offers promise for basic science, drug testing, disease modeling, personalized medicine, and translatable cell therapies across many tissue types. However, in practice many iPSC-derived cells have presented as immature in physiological function, and despite efforts to recapitulate adult maturity, most have yet to meet the necessary benchmarks for the intended tissues. Here, we summarize the available state of knowledge surrounding the physiological mechanisms underlying cell maturation in several key tissues. Common signaling consolidators, as well as potential synergies between critical signaling pathways are explored. Finally, current practices in physiologically relevant tissue engineering and experimental design are critically examined, with the goal of integrating greater decision paradigms and frameworks towards achieving efficient maturation strategies, which in turn may produce higher-valued iPSC-derived tissues.
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8
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He X, Cantrell AC, Williams QA, Chen J, Zeng H. TIGAR deficiency sensitizes angiotensin-II-induced renal fibrosis and glomerular injury. Physiol Rep 2022; 10:e15234. [PMID: 35441828 PMCID: PMC9020173 DOI: 10.14814/phy2.15234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 02/14/2022] [Accepted: 02/16/2022] [Indexed: 11/24/2022] Open
Abstract
Angiotensin II (Ang-II) is one of the major contributors to the progression of renal fibrosis, inflammation, glomerular injury, and chronic kidney disease. Emerging evidence suggests that renal glycolysis plays an important role in renal fibrosis and injury. TP53-induced glycolysis and apoptosis regulator (TIGAR) has been shown to regulate glycolysis. In the present study, we investigated the role of TIGAR in renal glycolysis, fibrosis, and glomerular injury during Ang-II-induced hypertension. Wild-type (WT) and TIGAR knockout (KO) mice were infused with Ang-II (1 µg/kg/min) via mini-pumps for 4 weeks. The mean arterial pressure was similar between the WT and TIGAR KO mice, associated with a comparable increase in plasma creatinine level. Ang-II infusion resulted in a significant increase in renal interstitial fibrosis and more mesangial expansion and collapsed glomerular structure in the TIGAR KO mice. These were associated with elevated expression of hypoxia-inducible factor-1 alpha, glycolytic enzymes, and transforming growth factor beta 1 in the TIGAR KO mice after Ang-II infusion when compared to that of the WT mice. The coupled-enzyme method revealed that PFK-1 activity was similarly increased in WT and TIGAR KO mice after Ang-II infusion. Our present study suggests that TIGAR is involved in Ang-II-induced renal fibrosis and glomerular injury, although it has little effect on blood pressure and renal function. Knockout of TIGAR sensitizes Ang-II-induced renal fibrosis and injury. This study provides new insights into the role of TIGAR in renal metabolism and pathological remodeling during Ang-II-induced hypertension.
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Affiliation(s)
- Xiaochen He
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterSchool of MedicineJacksonMississippiUSA
| | - Aubrey C. Cantrell
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterSchool of MedicineJacksonMississippiUSA
| | - Quinesha A. Williams
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterSchool of MedicineJacksonMississippiUSA
| | - Jian‐Xiong Chen
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterSchool of MedicineJacksonMississippiUSA
| | - Heng Zeng
- Department of Pharmacology and ToxicologyUniversity of Mississippi Medical CenterSchool of MedicineJacksonMississippiUSA
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9
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Wang L, Xing X, Zeng X, Jackson SR, TeSlaa T, Al-Dalahmah O, Samarah LZ, Goodwin K, Yang L, McReynolds MR, Li X, Wolff JJ, Rabinowitz JD, Davidson SM. Spatially resolved isotope tracing reveals tissue metabolic activity. Nat Methods 2022; 19:223-230. [PMID: 35132243 PMCID: PMC10926149 DOI: 10.1038/s41592-021-01378-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 12/13/2021] [Indexed: 11/09/2022]
Abstract
Isotope tracing has helped to determine the metabolic activities of organs. Methods to probe metabolic heterogeneity within organs are less developed. We couple stable-isotope-labeled nutrient infusion to matrix-assisted laser desorption ionization imaging mass spectrometry (iso-imaging) to quantitate metabolic activity in mammalian tissues in a spatially resolved manner. In the kidney, we visualize gluconeogenic flux and glycolytic flux in the cortex and medulla, respectively. Tricarboxylic acid cycle substrate usage differs across kidney regions; glutamine and citrate are used preferentially in the cortex and fatty acids are used in the medulla. In the brain, we observe spatial gradations in carbon inputs to the tricarboxylic acid cycle and glutamate under a ketogenic diet. In a carbohydrate-rich diet, glucose predominates throughout but in a ketogenic diet, 3-hydroxybutyrate contributes most strongly in the hippocampus and least in the midbrain. Brain nitrogen sources also vary spatially; branched-chain amino acids contribute most in the midbrain, whereas ammonia contributes in the thalamus. Thus, iso-imaging can reveal the spatial organization of metabolic activity.
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Affiliation(s)
- Lin Wang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | - Xi Xing
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Xianfeng Zeng
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - S RaElle Jackson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Tara TeSlaa
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Osama Al-Dalahmah
- Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, NY, USA
| | - Laith Z Samarah
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Katharine Goodwin
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Lifeng Yang
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Melanie R McReynolds
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
| | - Xiaoxuan Li
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Chemistry, Princeton University, Princeton, NJ, USA
| | | | - Joshua D Rabinowitz
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA
- Department of Chemistry, Princeton University, Princeton, NJ, USA
- Department of Molecular Biology, Princeton University, Princeton, NJ, USA
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA
- Ludwig Princeton Cancer Institute, Princeton, NJ, USA
| | - Shawn M Davidson
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ, USA.
- Rutgers Cancer Institute of New Jersey, New Brunswick, NJ, USA.
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10
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Wen L, Li Y, Li S, Hu X, Wei Q, Dong Z. Glucose Metabolism in Acute Kidney Injury and Kidney Repair. Front Med (Lausanne) 2021; 8:744122. [PMID: 34912819 PMCID: PMC8666949 DOI: 10.3389/fmed.2021.744122] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/19/2021] [Indexed: 12/13/2022] Open
Abstract
The kidneys play an indispensable role in glucose homeostasis via glucose reabsorption, production, and utilization. Conversely, aberrant glucose metabolism is involved in the onset, progression, and prognosis of kidney diseases, including acute kidney injury (AKI). In this review, we describe the regulation of glucose homeostasis and related molecular factors in kidneys under normal physiological conditions. Furthermore, we summarize recent investigations about the relationship between glucose metabolism and different types of AKI. We also analyze the involvement of glucose metabolism in kidney repair after injury, including renal fibrosis. Further research on glucose metabolism in kidney injury and repair may lead to the identification of novel therapeutic targets for the prevention and treatment of kidney diseases.
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Affiliation(s)
- Lu Wen
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China.,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States.,Research Department, Charlie Norwood VA Medical Center, Augusta, GA, United States
| | - Ying Li
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Siyao Li
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China.,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States.,Research Department, Charlie Norwood VA Medical Center, Augusta, GA, United States
| | - Xiaoru Hu
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China.,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States.,Research Department, Charlie Norwood VA Medical Center, Augusta, GA, United States
| | - Qingqing Wei
- Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States.,Research Department, Charlie Norwood VA Medical Center, Augusta, GA, United States
| | - Zheng Dong
- Hunan Key Laboratory of Kidney Disease and Blood Purification, Department of Nephrology, The Second Xiangya Hospital of Central South University, Changsha, China.,Department of Cellular Biology and Anatomy, Medical College of Georgia at Augusta University, Augusta, GA, United States.,Research Department, Charlie Norwood VA Medical Center, Augusta, GA, United States
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11
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Emery JM, Ortiz RM. Mitofusin 2: A link between mitochondrial function and substrate metabolism? Mitochondrion 2021; 61:125-137. [PMID: 34536562 DOI: 10.1016/j.mito.2021.09.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Revised: 08/22/2021] [Accepted: 09/13/2021] [Indexed: 01/18/2023]
Abstract
Mitochondria are dynamic, interactive organelles that connect cellular signaling and whole-cell homeostasis. This "mitochatting" allows the cell to receive information about the mitochondria's condition before accommodating energy demands. Mitofusin 2 (Mfn2), an outer mitochondrial membrane fusion protein specializes in mediating mitochondrial homeostasis. Early studies defined the biological significance of Mfn2, while latter studies highlighted its role in substrate metabolism. However, determining Mfn2 potential to contribute to energy homeostasis needs study. This review summarizes current literature on mitochondrial metabolic processes, dynamics, and evidence of interactions among Mfn2 and regulatory processes that may link Mfn2's role in maintaining mitochondrial function and substrate metabolism.
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Affiliation(s)
- Janna M Emery
- Department of Molecular and Cellular Biology, School of Natural Sciences, University of California, Merced, United States.
| | - Rudy M Ortiz
- Department of Molecular and Cellular Biology, School of Natural Sciences, University of California, Merced, United States
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12
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Palmer BF, Clegg DJ. Starvation Ketosis and the Kidney. Am J Nephrol 2021; 52:467-478. [PMID: 34350876 DOI: 10.1159/000517305] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 05/14/2021] [Indexed: 02/03/2023]
Abstract
BACKGROUND The remarkable ability of the body to adapt to long-term starvation has been critical for survival of primitive man. An appreciation of these processes can provide the clinician better insight into many clinical conditions characterized by ketoacidosis. SUMMARY The body adapts to long-term fasting by conserving nitrogen, as the brain increasingly utilizes keto acids, sparing the need for glucose. This shift in fuel utilization decreases the need for mobilization of amino acids from the muscle for purposes of gluconeogenesis. Loss of urinary nitrogen is initially in the form of urea when hepatic gluconeogenesis is dominant and later as ammonia reflecting increased glutamine uptake by the kidney. The carbon skeleton of glutamine is utilized for glucose production and regeneration of consumed HCO3-. The replacement of urea with NH4+ provides the osmoles needed for urine flow and waste product excretion. Over time, the urinary loss of nitrogen is minimized as kidney uptake of filtered ketone bodies becomes more complete. Adjustments in urine Na+ serve to minimize kidney K+ wasting and, along with changes in urine pH, minimize the likelihood of uric acid precipitation. There is a sexual dimorphism in response to starvation. Key Message: Ketoacidosis is a major feature of common clinical conditions to include diabetic ketoacidosis, alcoholic ketoacidosis, salicylate intoxication, SGLT2 inhibitor therapy, and calorie sufficient but carbohydrate-restricted diets. Familiarity with the pathophysiology and metabolic consequences of ketogenesis is critical, given the potential for the clinician to encounter one of these conditions.
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Affiliation(s)
- Biff F Palmer
- Division of Nephrology, Department of Medicine, University of Texas Southwestern Medical Center, El Paso, Texas, USA
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13
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Rawls KD, Dougherty BV, Vinnakota KC, Pannala VR, Wallqvist A, Kolling GL, Papin JA. Predicting changes in renal metabolism after compound exposure with a genome-scale metabolic model. Toxicol Appl Pharmacol 2021; 412:115390. [PMID: 33387578 PMCID: PMC7859602 DOI: 10.1016/j.taap.2020.115390] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 11/02/2020] [Accepted: 12/26/2020] [Indexed: 12/12/2022]
Abstract
The kidneys are metabolically active organs with importance in several physiological tasks such as the secretion of soluble wastes into the urine and synthesizing glucose and oxidizing fatty acids for energy in fasting (non-fed) conditions. Once damaged, the metabolic capability of the kidneys becomes altered. Here, we define metabolic tasks in a computational modeling framework to capture kidney function in an update to the iRno network reconstruction of rat metabolism using literature-based evidence. To demonstrate the utility of iRno for predicting kidney function, we exposed primary rat renal proximal tubule epithelial cells to four compounds with varying levels of nephrotoxicity (acetaminophen, gentamicin, 2,3,7,8-tetrachlorodibenzodioxin, and trichloroethylene) for six and twenty-four hours, and collected transcriptomics and metabolomics data to measure the metabolic effects of compound exposure. For the transcriptomics data, we observed changes in fatty acid metabolism and amino acid metabolism, as well as changes in existing markers of kidney function such as Clu (clusterin). The iRno metabolic network reconstruction was used to predict alterations in these same pathways after integrating transcriptomics data and was able to distinguish between select compound-specific effects on the proximal tubule epithelial cells. Genome-scale metabolic network reconstructions with coupled omics data can be used to predict changes in metabolism as a step towards identifying novel metabolic biomarkers of kidney function and dysfunction.
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Affiliation(s)
- Kristopher D Rawls
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Bonnie V Dougherty
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA
| | - Kalyan C Vinnakota
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, MD 21702, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. (HJF), Bethesda, MD 20817, USA
| | - Venkat R Pannala
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, MD 21702, USA; Henry M. Jackson Foundation for the Advancement of Military Medicine, Inc. (HJF), Bethesda, MD 20817, USA
| | - Anders Wallqvist
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, U.S. Army Medical Research and Development Command, Fort Detrick, MD 21702, USA
| | - Glynis L Kolling
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA; Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
| | - Jason A Papin
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22908, USA; Department of Medicine, Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA; Department of Biochemistry & Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA.
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14
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Zhang PN, Zhou MQ, Guo J, Zheng HJ, Tang J, Zhang C, Liu YN, Liu WJ, Wang YX. Mitochondrial Dysfunction and Diabetic Nephropathy: Nontraditional Therapeutic Opportunities. J Diabetes Res 2021; 2021:1010268. [PMID: 34926696 PMCID: PMC8677373 DOI: 10.1155/2021/1010268] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2021] [Accepted: 11/02/2021] [Indexed: 12/12/2022] Open
Abstract
Diabetic nephropathy (DN) is a progressive microvascular diabetic complication. Growing evidence shows that persistent mitochondrial dysfunction contributes to the progression of renal diseases, including DN, as it alters mitochondrial homeostasis and, in turn, affects normal kidney function. Pharmacological regulation of mitochondrial networking is a promising therapeutic strategy for preventing and restoring renal function in DN. In this review, we have surveyed recent advances in elucidating the mitochondrial networking and signaling pathways in physiological and pathological contexts. Additionally, we have considered the contributions of nontraditional therapy that ameliorate mitochondrial dysfunction and discussed their molecular mechanism, highlighting the potential value of nontraditional therapies, such as herbal medicine and lifestyle interventions, in therapeutic interventions for DN. The generation of new insights using mitochondrial networking will facilitate further investigations on nontraditional therapies for DN.
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Affiliation(s)
- Ping Na Zhang
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
| | - Meng Qi Zhou
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
| | - Jing Guo
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
| | - Hui Juan Zheng
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
| | - Jingyi Tang
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
| | - Chao Zhang
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
| | - Yu Ning Liu
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
| | - Wei Jing Liu
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
- Institute of Nephrology and Zhanjiang Key Laboratory of Prevention and Management of Chronic Kidney Disease, Guangdong Medical University, Zhanjiang, China
| | - Yao Xian Wang
- Renal Research Institution of Beijing University of Chinese Medicine and Key Laboratory of Chinese Internal Medicine of Ministry of Education and Beijing, Dongzhimen Hospital Affiliated to Beijing University of Chinese Medicine, Shipping Warehouse No. 5, Beijing 100700, China
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15
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Legouis D, Faivre A, Cippà PE, de Seigneux S. Renal gluconeogenesis: an underestimated role of the kidney in systemic glucose metabolism. Nephrol Dial Transplant 2020; 37:1417-1425. [PMID: 33247734 DOI: 10.1093/ndt/gfaa302] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Indexed: 12/21/2022] Open
Abstract
Glucose levels are tightly regulated at all times. Gluconeogenesis is the metabolic pathway dedicated to glucose synthesis from non-hexose precursors. Gluconeogenesis is critical for glucose homoeostasis, particularly during fasting or stress conditions. The renal contribution to systemic gluconeogenesis is increasingly recognized. During the post-absorptive phase, the kidney accounts for ∼40% of endogenous gluconeogenesis, occurring mainly in the kidney proximal tubule. The main substrate for renal gluconeogenesis is lactate and the process is regulated by insulin and cellular glucose levels, but also by acidosis and stress hormones. The kidney thus plays an important role in the maintenance of glucose and lactate homoeostasis during stress conditions. The impact of acute and chronic kidney disease and proximal tubular injury on gluconeogenesis is not well studied. Recent evidence shows that in both experimental and clinical acute kidney injury, impaired renal gluconeogenesis could significantly participate in systemic metabolic disturbance and thus alter the prognosis. This review summarizes the biochemistry of gluconeogenesis, the current knowledge of kidney gluconeogenesis, its modifications in kidney disease and the clinical relevance of this fundamental biological process in human biology.
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Affiliation(s)
- David Legouis
- Department of Acute Medicine, Division of Intensive Care, University Hospitals of Geneva, Geneva, Switzerland.,Department of Medicine, Laboratory of Nephrology, University Hospitals of Geneva, Geneva, Switzerland.,Department of Cell Physiology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anna Faivre
- Department of Medicine, Laboratory of Nephrology, University Hospitals of Geneva, Geneva, Switzerland.,Department of Cell Physiology, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Pietro E Cippà
- Division of Nephrology, Ente Ospedaliero Cantonale, Lugano, Switzerland
| | - Sophie de Seigneux
- Department of Medicine, Laboratory of Nephrology, University Hospitals of Geneva, Geneva, Switzerland.,Department of Cell Physiology, Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Department of Medicine, Division of Nephrology, University Hospitals of Geneva, Geneva, Switzerland
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16
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Robak P, Ożgo M, Lepczyński A, Herosimczyk A, Barszcz M, Taciak M, Skomiał J. Proteome changes in renal cortex and medulla induced by dietary supplementation with inulin-type fructans in growing pigs. J Anim Physiol Anim Nutr (Berl) 2019; 103:1837-1847. [PMID: 31368153 DOI: 10.1111/jpn.13170] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 03/29/2019] [Accepted: 06/30/2019] [Indexed: 12/15/2022]
Abstract
The aim of the study was to evaluate the influence of dietary supplementation with inulin extract from chicory root and dried chicory root on the protein profile of the renal cortex and medulla of growing pigs. The experiment was carried out on renal cortex and medulla tissue collected from 24 50-day-old PIC x Penarlan P76 crossbred piglets (males). Animals were divided into three dietary groups (n = 8) and fed with a control diet, diet supplemented with 2% inulin extract from chicory root and a diet supplemented with 4% dried chicory root. Kidney samples were collected after 40 days of feeding, and renal cortex and medulla proteins were separated by two-dimensional electrophoresis. Protein identification was performed using MALDI-TOF mass spectrometry. The diet supplemented with 2% chicory inulin induced significant expression changes of 20 and 26 protein spots in the renal cortex and medulla respectively. Supplementation with 4% dried chicory root triggered changes in the expression of 44 and 24 proteins in the renal cortex and medulla respectively. Both forms of chicory inulin-type fructans effectively affected the expression of proteins involved in energy metabolism, heat shock proteins and other chaperones, cytoskeletal and cytoskeleton-related proteins, as well as other proteins. Additionally, changes in transferrin abundance in both experimental groups suggested the significance of chicory fructan supplementation for iron absorption and bioavailability. In conclusion, 2% inulin extract from chicory root and 4% dried chicory root exerted a similar effect on changes in renal protein expression; however, more pronounced alterations were induced by dried chicory root. Nevertheless, further studies are needed for better understanding the mechanism underlying the effect of chicory inulin-type fructans and their fermentation end products on the kidneys of growing pigs.
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Affiliation(s)
- Paulina Robak
- Department of Physiology, Cytobiology and Proteomics, Faculty of Biotechnology and Animal Husbandry, West Pomeranian University of Technology Szczecin, Szczecin, Poland
| | - Małgorzata Ożgo
- Department of Physiology, Cytobiology and Proteomics, Faculty of Biotechnology and Animal Husbandry, West Pomeranian University of Technology Szczecin, Szczecin, Poland
| | - Adam Lepczyński
- Department of Physiology, Cytobiology and Proteomics, Faculty of Biotechnology and Animal Husbandry, West Pomeranian University of Technology Szczecin, Szczecin, Poland
| | - Agnieszka Herosimczyk
- Department of Physiology, Cytobiology and Proteomics, Faculty of Biotechnology and Animal Husbandry, West Pomeranian University of Technology Szczecin, Szczecin, Poland
| | - Marcin Barszcz
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
| | - Marcin Taciak
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
| | - Jacek Skomiał
- Department of Animal Nutrition, The Kielanowski Institute of Animal Physiology and Nutrition, Polish Academy of Sciences, Jabłonna, Poland
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17
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Otsuka Y, Furihata T, Nakagawa K, Ohno Y, Reien Y, Ouchi M, Wakashin H, Tsuruoka S, Anzai N. Sodium-coupled monocarboxylate transporter 1 interacts with the RING finger- and PDZ domain-containing protein PDZRN3. J Physiol Sci 2019; 69:635-642. [PMID: 31098988 PMCID: PMC10717332 DOI: 10.1007/s12576-019-00681-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 04/27/2019] [Indexed: 10/26/2022]
Abstract
Sodium-coupled monocarboxylate transporter SMCT1 (SLC5A8) mediates monocarboxylate transport in the proximal tubule of the kidney. We have identified PDZK1 and PDZ domain-containing RING finger 3 (PDZRN3) as potent binding partners of SMCT1, which has a PDZ motif (Thr-Arg-Leu), by yeast two-hybrid screening and revealed that PDZK1 enhances the transport activity of SMCT1. In this study, we aimed to characterize the interaction between SMCT1 and PDZRN3 as well as to examine how PDZRN3 regulates SMCT1 function. An interaction between SMCT1 and PDZRN3 through the PDZ motif was observed in a co-immunoprecipitation assay and yeast two-hybrid assay. A transport assay showed that PDZRN3 abolished the enhancing effect of PDZK1 on nicotinate uptake via SMCT1. Our results suggest that SMCT1 interacts with PDZRN3 and that PDZRN3 may regulate SMCT1 function by interfering with the interaction between SMCT1 and PDZK1.
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Affiliation(s)
- Yusuke Otsuka
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuou-ku, Chiba, 260-8670, Japan
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
- Department of Nephrology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Tomomi Furihata
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Kiyoshi Nakagawa
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Yuta Ohno
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuou-ku, Chiba, 260-8670, Japan
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Yoshie Reien
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Motoshi Ouchi
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan
| | - Hidefumi Wakashin
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuou-ku, Chiba, 260-8670, Japan
| | - Shuichi Tsuruoka
- Department of Nephrology, Graduate School of Medicine, Nippon Medical School, Tokyo, Japan
| | - Naohiko Anzai
- Department of Pharmacology, Chiba University Graduate School of Medicine, 1-8-1, Inohana, Chuou-ku, Chiba, 260-8670, Japan.
- Department of Pharmacology and Toxicology, Dokkyo Medical University School of Medicine, Tochigi, Japan.
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18
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Lyu Z, Mao Z, Li Q, Xia Y, Liu Y, He Q, Wang Y, Zhao H, Lu Z, Zhou Q. PPARγ maintains the metabolic heterogeneity and homeostasis of renal tubules. EBioMedicine 2018; 38:178-190. [PMID: 30420298 PMCID: PMC6306377 DOI: 10.1016/j.ebiom.2018.10.072] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/22/2018] [Accepted: 10/31/2018] [Indexed: 02/03/2023] Open
Abstract
Background The renal tubules, which have distant metabolic features and functions in different segments, reabsorb >99% of approximately 180 l of water and 25,000 mmol of Na + daily. Defective metabolism in renal tubules is involved in the pathobiology of kidney diseases. However, the mechanisms underlying the metabolic regulation in renal tubules remain to be defined. Methods We quantitatively compared the proteomes of the isolated proximal tubules (PT) and distal tubules (DT) from C57BL/6 mouse using tandem mass tag (TMT) labeling-based quantitative mass spectrometry. Bioinformatics analysis of the differentially expressed proteins revealed the significant differences between PT and DT in metabolism pathway. We also performed in vitro and in vivo assays to investigate the molecular mechanism underlying the distant metabolic features in PT and DT. Findings We demonstrate that the renal proximal tubule (PT) has high expression of lipid metabolism enzymes, which is transcriptionally upregulated by abundantly expressed PPARα/γ. In contrast, the renal distal tubule (DT) has elevated glycolytic enzyme expression, which is mediated by highly expressed c-Myc. Importantly, PPARγ transcriptionally enhances the protease iRhom2 expression in PT, which suppresses EGF expression and secretion and subsequent EGFR-dependent glycolytic gene expression and glycolysis. PPARγ inhibition reduces iRhom2 expression and increases EGF and GLUT1 expression in PT in mice, resulting in renal tubule hypertrophy, tubulointerstitial fibrosis and damaged kidney functions, which are rescued by 2-deoxy-d-glucose treatment. Interpretation These findings delineate instrumental mechanisms underlying the active lipid metabolism and suppressed glycolysis in PT and active glycolysis in DT and reveal critical roles for PPARs and c-Myc in maintaining renal metabolic homeostasis. FUND: This work was supported by the National Natural Science Foundation of China (grants 81572076 and 81873932; to Q.Z.), the Applied Development Program of the Science and Technology Committee of Chongqing (cstc2014yykfB10003; Q.Z.), the Program of Populace Creativities Workshops of the Science and Technology Committee of Chongqing (Q.Z.), the special demonstration programs for innovation and application of techniques (cstc2018jscx-mszdX0022) from the Science and Technology Committee of Chongqing (Q.Z.).
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Affiliation(s)
- Zhongshi Lyu
- The Division of Molecular Nephrology, The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The School of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Zhaomin Mao
- The Division of Molecular Nephrology, The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The School of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Qianyin Li
- The Division of Molecular Nephrology, The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The School of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China
| | - Yan Xia
- Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Yamin Liu
- The Division of Molecular Nephrology, The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The School of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China
| | - Qingling He
- The Division of Molecular Nephrology, The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The School of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China
| | - Yingchun Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, People's Republic of China
| | - Hui Zhao
- Key Laboratory for Regenerative Medicine, Ministry of Education, School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong Special Administrative Region
| | - Zhimin Lu
- Department of Neuro-Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; Department of Molecular and Cellular Oncology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA; The University of Texas Graduate School of Biomedical Sciences at Houston, Houston, TX, USA
| | - Qin Zhou
- The Division of Molecular Nephrology, The M.O.E. Key Laboratory of Laboratory Medical Diagnostics, The School of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China.
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Abstract
Globally, diabetes is the leading cause of chronic kidney disease and end-stage renal disease, which are major risk factors for cardiovascular disease and death. Despite this burden, the factors that precipitate the development and progression of diabetic kidney disease (DKD) remain to be fully elucidated. Mitochondrial dysfunction is associated with kidney disease in nondiabetic contexts, and increasing evidence suggests that dysfunctional renal mitochondria are pathological mediators of DKD. These complex organelles have a broad range of functions, including the generation of ATP. The kidneys are mitochondrially rich, highly metabolic organs that require vast amounts of ATP for their normal function. The delivery of metabolic substrates for ATP production, such as fatty acids and oxygen, is altered by diabetes. Changes in metabolic fuel sources in diabetes to meet ATP demands result in increased oxygen consumption, which contributes to renal hypoxia. Inherited factors including mutations in genes that impact mitochondrial function and/or substrate delivery may also be important risk factors for DKD. Hence, we postulate that the diabetic milieu and inherited factors that underlie abnormalities in mitochondrial function synergistically drive the development and progression of DKD.
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Affiliation(s)
- Josephine M Forbes
- Glycation and Diabetes Group, Mater Research Institute, The University of Queensland, Translational Research Institute, Brisbane, Queensland, Australia.,Mater Clinical School, School of Medicine, The University of Queensland, St Lucia, Queensland, Australia.,Departments of Medicine and Paediatrics, The University of Melbourne, Parkville, Victoria, Australia
| | - David R Thorburn
- Departments of Medicine and Paediatrics, The University of Melbourne, Parkville, Victoria, Australia.,Murdoch Children's Research Institute, Royal Children's Hospital, Parkville, Victoria, Australia
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20
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Ward MS, Flemming NB, Gallo LA, Fotheringham AK, McCarthy DA, Zhuang A, Tang PH, Borg DJ, Shaw H, Harvie B, Briskey DR, Roberts LA, Plan MR, Murphy MP, Hodson MP, Forbes JM. Targeted mitochondrial therapy using MitoQ shows equivalent renoprotection to angiotensin converting enzyme inhibition but no combined synergy in diabetes. Sci Rep 2017; 7:15190. [PMID: 29123192 PMCID: PMC5680236 DOI: 10.1038/s41598-017-15589-x] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 10/20/2017] [Indexed: 12/14/2022] Open
Abstract
Mitochondrial dysfunction is a pathological mediator of diabetic kidney disease (DKD). Our objective was to test the mitochondrially targeted agent, MitoQ, alone and in combination with first line therapy for DKD. Intervention therapies (i) vehicle (D); (ii) MitoQ (DMitoQ;0.6 mg/kg/day); (iii) Ramipril (DRam;3 mg/kg/day) or (iv) combination (DCoAd) were administered to male diabetic db/db mice for 12 weeks (n = 11–13/group). Non-diabetic (C) db/m mice were followed concurrently. No therapy altered glycaemic control or body weight. By the study end, both monotherapies improved renal function, decreasing glomerular hyperfiltration and albuminuria. All therapies prevented tubulointerstitial collagen deposition, but glomerular mesangial expansion was unaffected. Renal cortical concentrations of ATP, ADP, AMP, cAMP, creatinine phosphate and ATP:AMP ratio were increased by diabetes and mostly decreased with therapy. A higher creatine phosphate:ATP ratio in diabetic kidney cortices, suggested a decrease in ATP consumption. Diabetes elevated glucose 6-phosphate, fructose 6-phosphate and oxidised (NAD+ and NADP+) and reduced (NADH) nicotinamide dinucleotides, which therapy decreased generally. Diabetes increased mitochondrial oxygen consumption (OCR) at complex II-IV. MitoQ further increased OCR but decreased ATP, suggesting mitochondrial uncoupling as its mechanism of action. MitoQ showed renoprotection equivalent to ramipril but no synergistic benefits of combining these agents were shown.
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Affiliation(s)
- Micheal S Ward
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Nicole B Flemming
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia.,Schools of Biomedical Sciences, Woolloongabba, Queensland, Australia
| | - Linda A Gallo
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia.,Schools of Biomedical Sciences, Woolloongabba, Queensland, Australia
| | - Amelia K Fotheringham
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia.,Schools of Biomedical Sciences, Woolloongabba, Queensland, Australia
| | - Domenica A McCarthy
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Aowen Zhuang
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia.,Medicine, Schools of Biomedical Sciences, Woolloongabba, Queensland, Australia
| | - Peter H Tang
- Department of Paediatrics, University of Cincinnati, Cincinnati, Ohio, USA
| | - Danielle J Borg
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia.,Schools of Biomedical Sciences, Woolloongabba, Queensland, Australia
| | - Hannah Shaw
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia
| | - Benjamin Harvie
- The University of Queensland Biological Resources, St Lucia, Queensland, Australia
| | - David R Briskey
- Human Movement and Nutrition Sciences, St Lucia, Queensland, Australia
| | - Llion A Roberts
- Human Movement and Nutrition Sciences, St Lucia, Queensland, Australia
| | - Manuel R Plan
- Metabolomics Australia Queensland Node, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland, Australia
| | - Michael P Murphy
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Mark P Hodson
- Medicine, Schools of Biomedical Sciences, Woolloongabba, Queensland, Australia.,Pharmacy The University of Queensland, St Lucia, Queensland, Australia.,Metabolomics Australia Queensland Node, Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, St Lucia, Queensland, Australia
| | - Josephine M Forbes
- Glycation and Diabetes Group, Mater Research Institute-The University of Queensland, Translational Research Institute, Woolloongabba, Queensland, Australia. .,Medicine, Schools of Biomedical Sciences, Woolloongabba, Queensland, Australia. .,Department of Medicine, The University of Melbourne, Heidelberg, Australia.
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21
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Abstract
The kidney requires a large number of mitochondria to remove waste from the blood and regulate fluid and electrolyte balance. Mitochondria provide the energy to drive these important functions and can adapt to different metabolic conditions through a number of signalling pathways (for example, mechanistic target of rapamycin (mTOR) and AMP-activated protein kinase (AMPK) pathways) that activate the transcriptional co-activator peroxisome proliferator-activated receptor-γ co-activator 1α (PGC1α), and by balancing mitochondrial dynamics and energetics to maintain mitochondrial homeostasis. Mitochondrial dysfunction leads to a decrease in ATP production, alterations in cellular functions and structure, and the loss of renal function. Persistent mitochondrial dysfunction has a role in the early stages and progression of renal diseases, such as acute kidney injury (AKI) and diabetic nephropathy, as it disrupts mitochondrial homeostasis and thus normal kidney function. Improving mitochondrial homeostasis and function has the potential to restore renal function, and administering compounds that stimulate mitochondrial biogenesis can restore mitochondrial and renal function in mouse models of AKI and diabetes mellitus. Furthermore, inhibiting the fission protein dynamin 1-like protein (DRP1) might ameliorate ischaemic renal injury by blocking mitochondrial fission.
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Abstract
SIGNIFICANCE Reactive oxygen species (ROS) reactive nitrogen species (RNS) and redox processes are of key importance in obesity- and diabetes-related kidney disease; however, there remains significant controversy in the field. RECENT ADVANCES New data from imaging and in vivo models of obesity and diabetic kidney disease have shed new insights into this field. In the setting of obesity- and diabetes-related kidney injury, there is a growing recognition that the major moieties of ROS and RNS are hydrogen peroxide and peroxynitrite with the enzymatic sources being NADPH oxidases and nitric oxide synthase, respectively. However, the role of mitochondrial superoxide as a driver of renal complications remains unclear. CRITICAL ISSUES Several key issues that are often not discussed are the specific ROS and RNS molecules, the source of generation, the location of production, and downstream targets. FUTURE DIRECTIONS Further understanding of the role of ROS/RNS/redox and their relationship with key signaling and metabolic pathways such as AMP-activated protein kinase (AMPK) and hypoxia-inducible factor 1-α (HIF1α) will be critical to a new understanding of kidney complications of caloric challenges and new therapeutic approaches. Antioxid. Redox Signal. 25, 208-216.
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Affiliation(s)
- Kumar Sharma
- 1 Center for Renal Translational Medicine, Institute of Metabolomic Medicine, University of California San Diego , La Jolla, California.,2 Division of Nephrology-Hypertension, Veterans Affairs San Diego Healthcare System , La Jolla, California
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23
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Di Chiara M, Glaudemans B, Loffing-Cueni D, Odermatt A, Al-Hasani H, Devuyst O, Faresse N, Loffing J. Rab-GAP TBC1D4 (AS160) is dispensable for the renal control of sodium and water homeostasis but regulates GLUT4 in mouse kidney. Am J Physiol Renal Physiol 2015; 309:F779-90. [PMID: 26336159 DOI: 10.1152/ajprenal.00139.2015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 08/29/2015] [Indexed: 12/17/2022] Open
Abstract
The Rab GTPase-activating protein TBC1D4 (AS160) controls trafficking of the glucose transporter GLUT4 in adipocytes and skeletal muscle cells. TBC1D4 is also highly abundant in the renal distal tubule, although its role in this tubule is so far unknown. In vitro studies suggest that it is involved in the regulation of renal transporters and channels such as the epithelial sodium channel (ENaC), aquaporin-2 (AQP2), and the Na+-K+-ATPase. To assess the physiological role of TBC1D4 in the kidney, wild-type (TBC1D4+/+) and TBC1D4-deficient (TBC1D4-/-) mice were studied. Unexpectedly, neither under standard nor under challenging conditions (low Na+/high K+, water restriction) did TBC1D4-/- mice show any difference in urinary Na+ and K+ excretion, urine osmolarity, plasma ion and aldosterone levels, and blood pressure compared with TBC1D4+/+ mice. Also, immunoblotting did not reveal any change in the abundance of major renal sodium- and water-transporting proteins [Na-K-2Cl cotransporter (NKCC2) NKCC2, NaCl cotransporter (NCC), ENaC, AQP2, and the Na+-K+-ATPase]. However, the abundance of GLUT4, which colocalizes with TBC1D4 along the distal nephron of TBC1D4+/+ mice, was lower in whole kidney lysates of TBC1D4-/- mice than in TBC1D4+/+ mice. Likewise, primary thick ascending limb (TAL) cells isolated from TBC1D4-/- mice showed an increased basal glucose uptake and an abrogated insulin response compared with TAL cells from TBC1D4+/+ mice. Thus, TBC1D4 is dispensable for the regulation of renal Na+ and water transport, but may play a role for GLUT4-mediated basolateral glucose uptake in distal tubules. The latter may contribute to the known anaerobic glycolytic capacity of distal tubules during renal ischemia.
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Affiliation(s)
- Marianna Di Chiara
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland
| | - Bob Glaudemans
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | | | - Alex Odermatt
- Division of Molecular and Systems Toxicology, Pharmacenter, University of Basel, Basel, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
| | - Hadi Al-Hasani
- German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich-Heine-University and German Center for Diabetes Research, Düsseldorf, Germany
| | - Olivier Devuyst
- Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland; Institute of Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
| | - Nourdine Faresse
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
| | - Johannes Loffing
- Institute of Anatomy, University of Zurich, Zurich, Switzerland; Zurich Center of Integrative Human Physiology, University of Zurich, Zurich, Switzerland; National Center of Competence in Research "Kidney.CH," Switzerland; and
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Gerich JE, Bastien A. Development of the sodium-glucose co-transporter 2 inhibitor dapagliflozin for the treatment of patients with Type 2 diabetes mellitus. Expert Rev Clin Pharmacol 2014; 4:669-83. [DOI: 10.1586/ecp.11.54] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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25
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26
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Lier N, Gresko N, Chiara M, Loffing-Cueni D, Loffing J. Immunofluorescent localization of the Rab-GAP protein TBC1D4 (AS160) in mouse kidney. Histochem Cell Biol 2012; 138:101-12. [DOI: 10.1007/s00418-012-0944-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/14/2012] [Indexed: 10/28/2022]
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27
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Schley G, Klanke B, Schödel J, Forstreuter F, Shukla D, Kurtz A, Amann K, Wiesener MS, Rosen S, Eckardt KU, Maxwell PH, Willam C. Hypoxia-inducible transcription factors stabilization in the thick ascending limb protects against ischemic acute kidney injury. J Am Soc Nephrol 2011; 22:2004-15. [PMID: 21921145 DOI: 10.1681/asn.2010121249] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Hypoxia-inducible transcription factors (HIF) protect cells against oxygen deprivation, and HIF stabilization before ischemia mitigates tissue injury. Because ischemic acute kidney injury (AKI) often involves the thick ascending limb (TAL), modulation of HIF in this segment may be protective. Here, we generated mice with targeted TAL deletion of the von Hippel-Lindau protein (Vhl), which mediates HIF degradation under normoxia, using Tamm-Horsfall protein (Thp)-driven Cre expression. These mice showed strong expression of HIF-1α in TALs but no changes in kidney morphology or function under control conditions. Deficiency of Vhl in the TAL markedly attenuated proximal tubular injury and preserved TAL function following ischemia-reperfusion, which may be partially a result of enhanced expression of glycolytic enzymes and lactate metabolism. These results highlight the importance of the thick ascending limb in the pathogenesis of AKI and suggest that pharmacologically targeting the HIF system may have potential to prevent and mitigate AKI.
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Affiliation(s)
- Gunnar Schley
- Department of Nephrology and Hypertension, Friedrich-Alexander-University, Erlangen-Nuremberg, Krankenhausstrasse 12, 91054 Erlangen, Germany
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28
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Yang L, Vaitheesvaran B, Hartil K, Robinson AJ, Hoopmann MR, Eng JK, Kurland IJ, Bruce JE. The fasted/fed mouse metabolic acetylome: N6-acetylation differences suggest acetylation coordinates organ-specific fuel switching. J Proteome Res 2011; 10:4134-49. [PMID: 21728379 PMCID: PMC3204869 DOI: 10.1021/pr200313x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The elucidation of extra-nuclear lysine acetylation has been of growing interest, as the cosubstrate for acetylation, acetyl CoA, is at a key metabolic intersection. Our hypothesis was that mitochondrial and cytoplasmic protein acetylation may be part of a fasted/re-fed feedback control system for the regulation of the metabolic network in fuel switching, where acetyl CoA would be provided by fatty acid oxidation, or glycolysis, respectively. To test this, we characterized the mitochondrial and cytoplasmic acetylome in various organs that have a high metabolic rate relative to their mass, and/or switch fuels, under fasted and re-fed conditions (brain, kidney, liver, skeletal muscle, heart muscle, white and brown adipose tissues). Using immunoprecipitation, coupled with LC-MS/MS label free quantification, we show there is a dramatic variation in global quantitative profiles of acetylated proteins from different organs. In total, 733 acetylated peptides from 337 proteins were identified and quantified, out of which 31 acetylated peptides from the metabolic proteins that may play organ-specific roles were analyzed in detail. Results suggest that fasted/re-fed acetylation changes coordinated by organ-specific (de)acetylases in insulin-sensitive versus -insensitive organs may underlie fuel use and switching. Characterization of the tissue-specific acetylome should increase understanding of metabolic conditions wherein normal fuel switching is disrupted, such as in Type II diabetes.
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Affiliation(s)
- Li Yang
- Department of Chemistry, Washington State University, Pullman, Washington, 99164
| | - Bhavapriya Vaitheesvaran
- Department of Medicine, Stable Isotope and Metabolomics Core Facility, Albert Einstein College of Medicine Diabetes Center, Bronx, New York, 10461
| | - Kirsten Hartil
- Department of Medicine, Stable Isotope and Metabolomics Core Facility, Albert Einstein College of Medicine Diabetes Center, Bronx, New York, 10461
| | - Alan J. Robinson
- Medical Research Council Mitochondrial Biology Unit, Cambridge, CB2 0XY, United Kingdom
| | - Michael R. Hoopmann
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98109
| | - Jimmy K. Eng
- University of Washington Proteomics Resource, Seattle, Washington, 98109
| | - Irwin J. Kurland
- Department of Medicine, Stable Isotope and Metabolomics Core Facility, Albert Einstein College of Medicine Diabetes Center, Bronx, New York, 10461
| | - James E. Bruce
- Department of Genome Sciences, University of Washington, Seattle, Washington, 98109
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Basile J. A new approach to glucose control in type 2 diabetes: the role of kidney sodium-glucose co-transporter 2 inhibition. Postgrad Med 2011; 123:38-45. [PMID: 21680987 DOI: 10.3810/pgm.2011.07.2302] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hyperglycemia is a defining characteristic of type 2 diabetes mellitus and is a major risk factor associated with the development of many microvascular complications. There are numerous therapies currently available to treat hyperglycemia, but glycemic control rates remain poor. One potential reason is the decline in ß-cell function over time, which decreases the effectiveness of therapies that rely on insulin action. The kidney occupies a central position in the control of glucose homeostasis by its role in gluconeogenesis and by regulating glucose excretion. Under normal conditions, glucose filtered by the kidney is virtually totally reabsorbed in the proximal tubule by the sodium-glucose co-transporter 2 (SGLT2). Inhibition of SGLT2 is an attractive, insulin-independent target for increasing glucose excretion in the setting of hyperglycemia. A number of SGLT2 inhibitors have been synthesized, and results from preclinical studies have shown that they increase glucose excretion and normalize plasma glucose in diabetic models. Initial clinical data are promising and suggest that SGLT2 inhibitors may be a new therapeutic option for treating type 2 diabetes mellitus.
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Affiliation(s)
- Jan Basile
- Seinsheimer Cardiovascular Health Program, Medical University of South Carolina, Ralph H. Johnson VA Medical Center, Charleston, SC 29403, USA.
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30
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Luttropp D, Schade M, Baer PC, Bereiter-Hahn J. Respiration rate in human primary renal proximal and early distal tubular cells in vitro: Considerations for biohybrid renal devices. Biotechnol Prog 2011; 27:262-8. [DOI: 10.1002/btpr.520] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Revised: 07/26/2010] [Indexed: 11/09/2022]
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31
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Truong DM, Kaler G, Khandelwal A, Swaan PW, Nigam SK. Multi-level analysis of organic anion transporters 1, 3, and 6 reveals major differences in structural determinants of antiviral discrimination. J Biol Chem 2008; 283:8654-63. [PMID: 18174163 PMCID: PMC2417182 DOI: 10.1074/jbc.m708615200] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2007] [Revised: 12/04/2007] [Indexed: 11/06/2022] Open
Abstract
Long-term exposure to antivirals is associated with serious cellular toxicity to the kidney and other tissues. Organic anion transporters (OATs) are believed to mediate the cellular uptake, and hence cytotoxicity, of many antivirals. However, a systematic in vitro and ex vivo analysis of interactions between these compounds with various OAT isoforms has been lacking. To characterize substrate interactions with mOat1, mOat3, and mOat6, a fluorescence-based competition assay in Xenopus oocytes as well as wild-type and knock-out whole embryonic kidney (WEK) organ culture systems was developed using 6-carboxyfluorescein, 5-carboxyfluorescein, and fluorescein. Of nine common antiviral drugs assessed in oocytes, many manifested higher affinity for SLC22a6 (mOat1), originally identified as NKT (e.g. adefovir and cidofovir), two (ddC and ddI) manifested significantly higher affinity for mOat3, while mOat6 had comparatively low but measurable affinity for certain antivirals. A live organ staining approach combined with fluorescent uptake in WEK cultures allowed the visualization of OAT-mediated uptake ex vivo into developing proximal tubule-like structures, as well as quantification of substrate interactions of individual OAT isoforms. In general, antiviral specificity of SLC22a6 (Oat1) (in Oat3(-/-) WEK culture) and SLC22a8 (Oat3) (in Oat1(-/-) WEK culture) was consistent with the Xenopus oocyte data. The combined observations suggest SLC22a8 (Oat3) is the major transporter interacting with ddC and ddI. Finally, quantitative structure-activity relationship analysis of the nine antivirals' physicochemical descriptors with their OAT affinity indicates that antiviral preferences of mOat1 are explained by high polar surface areas (e.g. phosphate groups), whereas mOat3 prefers hydrogen bond acceptors (e.g. amines, ketones) and low rotatable bond numbers. In contrast, hydrogen bond donors (e.g. amides, alcohols) diminish binding to mOat6. This suggests that, despite sharing close overall sequence homology, Oat1, Oat3, and Oat6 have signficantly different binding pockets. Taken together, the data provide a basis for understanding potential drug interactions in combination antiviral therapy, as well as suggesting structural mdifications for drug design, especially in the context of targeting toward or away from specific tissues.
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Affiliation(s)
- David M Truong
- Department of Pediatrics, University of California at San Diego, La Jolla, CA 92093, USA
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32
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Zhang W, Edwards A. A model of glucose transport and conversion to lactate in the renal medullary microcirculation. Am J Physiol Renal Physiol 2005; 290:F87-102. [PMID: 16118395 DOI: 10.1152/ajprenal.00168.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In this study, we modeled mathematically the transport of glucose across renal medullary vasa recta and its conversion to lactate by anaerobic glycolysis. Uncertain parameter values were determined by seeking good agreement between predictions and experimental measurements of lactate generation rates, as well as glucose and lactate concentration ratios between the papilla and the corticomedullary junction; plausible kinetic rate constant and permeability values are summarized in tabular form. Our simulations indicate that countercurrent exchange of glucose from descending (DVR) to ascending vasa recta (AVR) in the outer medulla (OM) and upper inner medulla (IM) severely limits delivery to the deep inner medulla, thereby limiting medullary lactate generation. If the permeability to glucose of OMDVR and IMDVR is taken to be the same and equal to 4 x 10(-4) cm/s, the fraction of glucose that bypasses the IM is calculated as 54%; it is predicted as 37% if the presence of pericytes in OMDVR reduces the glucose permeability of these vessels by a factor of 2 relative to that of IMDVR. Our results also suggest that red blood cells (RBCs) act as a reservoir that reduces the bypass of glucose from DVR to AVR. The rate of lactate generation by anaerobic glycolysis of glucose supplied by blood from glomerular efferent arterioles is predicted to range from 2 to 8 nmol/s, in good agreement with lower estimates obtained from the literature (Bernanke D and Epstein FH. Am J Physiol 208: 541-545, 1965; Bartlett S, Espinal J, Janssens P, and Ross BD. Biochem J 219: 73-78, 1984).
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Affiliation(s)
- Wensheng Zhang
- Department of Chemical and Biological Engineering, Tufts Univ., Medford, MA 02155, USA
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Tanaka T, Kojima I, Ohse T, Inagi R, Miyata T, Ingelfinger JR, Fujita T, Nangaku M. Hypoxia-inducible factor modulates tubular cell survival in cisplatin nephrotoxicity. Am J Physiol Renal Physiol 2005; 289:F1123-33. [PMID: 15956779 DOI: 10.1152/ajprenal.00081.2005] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hypoxia-inducible factor (HIF)-1 is a transcription factor mediating cellular response to hypoxia. Although it is expressed in tubular cells of the ischemic kidney, its functional role is not fully clarified in the pathological context. In this study, we investigated a role of HIF in tubular cell apoptosis induced by cisplatin. HIF-1alpha was expressed in tubular cells in the outer medulla 3 days after cisplatin (6 mg/kg) administration. With the in vivo administration of cobalt to activate HIF, the number of apoptotic renal tubular cells became much smaller in the outer medulla, compared with the vehicle group. We also examined the functional role of HIF-1 in vitro using immortalized rat proximal tubular cells (IRPTC). In hypoxia, IRPTC that express dominant-negative (dn) HIF-1alpha showed impaired survival in cisplatin injury at variable doses (25-100 microM, 24 h), which was not obvious in normoxia. The observed difference in cell viability in hypoxia was associated with the increased number of apoptotic cells in dnHIF-1alpha clones (Hoechst 33258 staining). Studies on intracellular signaling revealed that the degree of cytochrome c release, dissipation of mitochondrial membrane potentials, and caspase-9 activity were all more prominent in dnHIF-1alpha clones than in control IRPTC, pointing to the accelerated signaling of mitochondrial pathways. We propose that HIF-1 mediates cytoprotection against cisplatin injury in hypoxic renal tubular cells, by reducing the number of apoptotic cells through stabilization of mitochondrial membrane integrity and suppression of apoptosis signaling. A possibility was suggested that activation of HIF-1 could be a new promising therapeutic target for hypoxic renal diseases.
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Affiliation(s)
- Tetsuhiro Tanaka
- Division of Nephrology and Endocrinology, University of Tokyo School of Medicine, Bunkyo-ku, Tokyo, Japan
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Eraly SA, Bush KT, Sampogna RV, Bhatnagar V, Nigam SK. The molecular pharmacology of organic anion transporters: from DNA to FDA? Mol Pharmacol 2004; 65:479-87. [PMID: 14978224 DOI: 10.1124/mol.65.3.479] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal organic anion secretion has been implicated in numerous clinically significant drug interactions and adverse reactions, indicating the importance of a detailed understanding of this pathway for the development of optimum therapeutics. With the cloning of multiple genes encoding organic anion transporters (OATs), the study of organic anion secretion has entered the molecular age. In this review, we focus on various aspects of the molecular biology and pharmacology of the OATs, including discussion of their structural biology, genomic organization in pairs, developmental regulation, toxicology, and pharmacogenetics. We propose functional, pathophysiological, and evolutionary hypotheses to help explain recent experimental and genomic data.
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Affiliation(s)
- Satish A Eraly
- Department of Medicine, University of California, San Diego, La Jolla, CA 92093-0693, USA
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35
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Eraly SA, Blantz RC, Bhatnagar V, Nigam SK. Novel aspects of renal organic anion transporters. Curr Opin Nephrol Hypertens 2003; 12:551-8. [PMID: 12920404 DOI: 10.1097/00041552-200309000-00011] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE OF REVIEW Organic anion transporters, transmembrane proteins present in the renal proximal tubule, are a critical component of the human drug excretion machinery. Recent advances have clarified the function of these transporters, with broad clinical implications for pharmacogenetics, drug interactions and adverse reactions. Here, we discuss these issues in the context of the basic biology of the transporters. RECENT FINDINGS Understanding of organic anion transporter function has proceeded on several fronts. The continued cataloging of organic anion transporter substrates has revealed that the transporters' activity likely underlies many common drug interactions and nephrotoxic adverse reactions. Meanwhile, immunohistochemical and physiological studies suggest their potential involvement in the apical as well as basolateral steps of renal organic anion secretion. In addition, studies of the genomic organization of these transporters reveal that they are found in pairs of similar and similarly expressed genes, suggesting that pair members are coordinately regulated. Finally, we hypothesize here that organic anion transporters might impact renal susceptibility to ischemia and toxic injury, because their uptake of substrates can result in the efflux of Krebs cycle intermediates, an important nutrient source for the proximal tubule. SUMMARY The study of these transporters will likely have a significant impact on renal pharmacology and pharmacogenetics. In this regard, the generation of organic anion transporter gene knockout mice could provide invaluable models for defects in renal drug-handling. Ultimately, detailed knowledge of organic anion transporter function will assist in the choice of optimum pharmacological therapies.
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Affiliation(s)
- Satish A Eraly
- Department of Medicine1, University of California, San Diego, 9500 Gilman Drive, La Jolla, Californian 92093-0693, USA.
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Conjard A, Martin M, Guitton J, Baverel G, Ferrier B. Gluconeogenesis from glutamine and lactate in the isolated human renal proximal tubule: longitudinal heterogeneity and lack of response to adrenaline. Biochem J 2001; 360:371-7. [PMID: 11716765 PMCID: PMC1222237 DOI: 10.1042/0264-6021:3600371] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent studies in vivo have suggested that, in humans in the postabsorptive state, the kidneys contribute a significant fraction of systemic gluconeogenesis, and that the stimulation of renal gluconeogenesis may fully explain the increase in systemic gluconeogenesis during adrenaline infusion. Given the potential importance of human renal gluconeogenesis in various physiological and pathophysiological situations, we have conducted a study in vitro to further characterize this metabolic process and its regulation. For this, successive segments (S1, S2 and S3) of human proximal tubules were dissected and incubated with physiological concentrations of glutamine or lactate, two potential gluconeogenic substrates that are taken up by the human kidney in vivo, and glucose production was measured. The effects of adrenaline, noradrenaline and cAMP, a well established stimulator of gluconeogenesis in animal kidney tubules, were also studied in suspensions of human renal proximal tubules. The results indicate that the three successive segments have about the same capacity to synthesize glucose from glutamine; by contrast, the S2 and S3 segments synthesize more glucose from lactate than the S1 segment. In the S2 and S3 segments, lactate appears to be a better gluconeogenic precursor than glutamine. The addition of cAMP, but not of adrenaline or noradrenaline, led to the stimulation of gluconeogenesis from lactate and glutamine by human proximal tubules. These results indicate that, in the human kidney in vivo, lactate might be the main gluconeogenic precursor, and that the stimulation of renal gluconeogenesis observed in vivo upon adrenaline infusion may result from an indirect action on the renal proximal tubule.
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Affiliation(s)
- A Conjard
- Laboratoire de Physiopathologie Métabolique et Rénale, Institut National de la Santé et de la Recherche Médicale, U499, Faculté de Médecine R.T.H. Laennec, rue G. Paradin, 69372 Lyon Cedex 08, France.
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Cano N. Inter-relationships between renal metabolism (both in physiology and renal dysfunction) and the liver. Curr Opin Clin Nutr Metab Care 2001; 4:279-85. [PMID: 11458021 DOI: 10.1097/00075197-200107000-00006] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Recently, evaluation of organ-specific glucose release showed that renal glucose release is of the same order of magnitude as splanchnic glucose release during the postabsorptive period. Moreover, renal glucose release appeared to be more sensitive to hormone action than did hepatic glucose release, and appeared to have a pre-eminent role during the adaptation to various physiological and pathological conditions. The kidney is now recognized as playing a key role in interorgan glucose metabolism, and particularly in the Cori cycle and glutamine-glucose cycle. During chronic renal failure the suppression of renal glucose release, together with impaired hormone action, decreased glycogen storage and abnormal liver gluconeogenesis, are responsible for an increased risk for hypoglycaemia.
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Affiliation(s)
- N Cano
- Service d'hépatogastroenterologie et Nutrition, Clinique Résidence du Parc, Marseille, France.
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38
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Abstract
Gene regulation mechanisms have evolved allowing cells to finetune the level of "endogenous" oxidative stress and to cope with increased free radicals from external sources. Levels of H2O2 are tightly controlled in E. coli by OxyR, which is activated by H2O2 to increase scavenging activities and limit H2O2 generation by the respiratory chain. Sub-micromolar levels of H2O2 are maintained in mammalian tissues, though the regulatory systems that govern this control are unknown. Excess superoxide triggers the soxRS system in E. coli, which is controlled by the oxidant-sensitive iron-sulfur centers of the SoxR protein. Nitric oxide activates SoxR by a different modification of the iron-sulfur centers. The soxRS regulon mobilizes diverse functions to scavenge free radicals and repair oxidative damage in macromolecules, and other mechanisms that exclude many environmental agents from the cell. Mammalian cells also sense and respond to sub-toxic levels of nitric oxide, activating expression of heme oxygenase 1 through stabilization of its mRNA. These inductions give rise to adaptive resistance to nitric oxide in neuronal and other cell types.
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Affiliation(s)
- B González-Flecha
- Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts 02115, USA
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39
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Burke TJ, Malhotra D, Shapiro JI. Factors maintaining a pH gradient within the kidney: role of the vasculature architecture. Kidney Int 1999; 56:1826-37. [PMID: 10571791 DOI: 10.1046/j.1523-1755.1999.00738.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The architecture of the vasa rectae produces significant oxygen (O2) "shunting" and marked decreases in renal medullary pO2 values. We hypothesized that carbon dioxide (CO2) trapping and increases in medullary pCO2 along with decreases in medullary pH values should also accompany this O2 shunting. METHODS We developed computer simulations employing a model of gas exchange through the countercurrent vasculature that predicted trapping of CO2 along with O2 shunting. To test the validity of this model directly, medullary pH was measured by using needle electrodes in the in situ kidney before and after the administration of mannitol or furosemide, or by decreasing blood flow with a transient decrease of renal perfusion pressure with a suprarenal clamp. Data are expressed as mean +/- SD. RESULTS Medullary pH was lower than cortical pH (7.20 +/- 0.09 vs. 7.39 +/- 0.08, P < 0.01). Mannitol caused a decrease in medullary pH to 7.02 +/- 0.07 (P < 0.01), whereas furosemide increased medullary pH to 7. 31 +/- 0.09 (P < 0.01). Brief periods of severe hypotension decreased medullary pH to 6.90 +/- 0.09 (P < 0.01). CONCLUSIONS These data demonstrate that a significant pH gradient exists within the kidney parenchyma. This gradient is related to the metabolic activity of the thick ascending limb of Henle and the countercurrent vascular architecture, and may be relevant to a variety of physiological phenomena involved in volume, electrolyte, and acid-based homeostasis.
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Affiliation(s)
- T J Burke
- Department of Medicine, Medical College of Ohio, Toledo, USA
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Chin E, Zamah AM, Landau D, Grønbcek H, Flyvbjerg A, LeRoith D, Bondy CA. Changes in facilitative glucose transporter messenger ribonucleic acid levels in the diabetic rat kidney. Endocrinology 1997; 138:1267-75. [PMID: 9048635 DOI: 10.1210/endo.138.3.5015] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Facilitative glucose transporter (GLUTs 1, 2, 4, and 5) messenger RNAs (mRNAs) are differentially distributed in the rat nephron: GLUT1 is widely expressed, GLUT4 is selectively concentrated in thick ascending limbs, and GLUT2 and 5 are exclusively localized in proximal tubules, consistent with differential roles for these transporters in renal glucose handling. In the present study, quantitative in situ hybridization was used to evaluate changes in these mRNA levels during acute (2 and 7 days) and chronic (30, 90, and 180 days) streptozotocin-induced diabetes mellitus (STZ-DM). Medullary GLUT1 and GLUT4 mRNA levels were significantly increased during the acute phase but returned to normal after 1 week. Cortical GLUT1 mRNA levels, however, were decreased significantly from 7 days through 6 months of STZ-DM. Cortical GLUT2 mRNA was slightly increased acutely and increased 5-fold in chronic STZ-DM, with the largest increase focally concentrated in the convoluted portion of the proximal tubule. Proximal tubule GLUT5 mRNA levels also were increased significantly during chronic STZ-DM. In summary, medullary GLUT1 and GLUT4 mRNA levels are acutely increased in STZ-DM, paralleling the increased renal epithelial metabolic activity accompanying early diabetes. Proximal tubular GLUT2 and 5 mRNA levels were increased in chronic STZ-DM, possibly adapting to the increased need for glucose transport out of these epithelial cells, whereas the concomitant decrease in cortical GLUT1 expression may reflect the decreased requirement for basolateral import of glucose into these same cells. Thus, renal GLUTs demonstrate complex, nephron segment-specific and duration-dependent responses to the effects of STZ-DM.
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Affiliation(s)
- E Chin
- Division of Endocrinology, University of Alabama at Birmingham, USA
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Prestel R, Storck M, Pooth R, Steinbach G, Hammer C, Abendroth D. Na-K/2Cl transporter inhibition for reduction of postis-chemic kidney failure tested in autologous reperfusion. Transpl Int 1996. [DOI: 10.1111/j.1432-2277.1996.tb01670.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Prestel R, Storck M, Pooth R, Steinbach G, Hammer C, Abendroth D. Na-K/2Cl transporter inhibition for reduction of postischemic kidney failure tested in autologous reperfusion. Transpl Int 1996; 9 Suppl 1:S437-41. [PMID: 8959881 DOI: 10.1007/978-3-662-00818-8_105] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Postischemic kidney function may be influenced by donor conditioning. The sulfamoyl-benzoate "piretanide" (P) is a diuretic agent with an inhibitory effect on the luminal Na-K-2CL-transporter system in the ascending part of the loop of Henle. A clinical pilot study demonstrated a lower rate of organ dysfunction following transplantation in humans when the donor organs were pretreated with piretanide. In an experimental ex vivo model the effect of piretanide on immediate organ function following long or short cold ischemia was studied. Porcine kidneys (n = 36) were removed after in situ transaortal hypothermic flushing with 21 Eurocollins solution. Following short storage (1 h, n = 18) or long storage (24 h, n = 18) the kidneys were reperfused with intraoperatively drawn heparinized autologous blood diluted with Ringer's lactate to a hematocrit of 25%. Urine flow was higher in the piretanide-pretreated group (p), especially after long storage. The electrolyte loss was comparable in both groups. Postischemic endogenous creatinine clearance was significantly elevated in the treatment group (4.45 +/- 0.6 ml/min per 100 mg in P vs 1.91 +/- 0.4 ml/min per 100 mg, in control, P < 0.05 Mann-Whitney test). Renal hemodynamics were improved by piretanide, resulting in significantly lower resistance and allowing higher flow during pressure-controlled perfusion. O2 consumption, representing general metabolic activity, was higher after long storage, indicating an earlier recovery from cold ischemia. In this ex vivo model, autologous reperfusion of porcine kidneys could be improved by piretanide pretreatment. Autoregulation of kidney vasculature was maintained as well as functional parameters such as creatinine clearance or gluconeogenesis. Therefore, piretanide may be used in larger clinical trials to further improve organ quality in times of donor shortage.
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Affiliation(s)
- R Prestel
- Institute for Surgical Research, LM University Munich, Germany
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Wexler ID, Du Y, Lisgaris MV, Mandal SK, Freytag SO, Yang BS, Liu TC, Kwon M, Patel MS, Kerr DS. Primary amino acid sequence and structure of human pyruvate carboxylase. BIOCHIMICA ET BIOPHYSICA ACTA 1994; 1227:46-52. [PMID: 7918683 DOI: 10.1016/0925-4439(94)90105-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Pyruvate carboxylase (PC) (pyruvate:carbon dioxide ligase (ADP-forming), EC 6.4.1.1.), a nuclear-encoded mitochondrial enzyme, catalyzes the conversion of pyruvate to oxaloacetate. We have isolated and characterized cDNAs spanning the entire coding region of human PC. The sequence of human PC has an open reading frame of 3537 nucleotides which encodes for a polypeptide with a length of 1178 amino acids. The identity of the cDNA as PC is confirmed by comparison to PC cDNAs of other species and sequenced peptide fragments of mammalian PC. The M(r) of the full length precursor protein is 129,576 and that of the mature apoprotein is 127,370. RNA blot analysis from a variety of human tissues demonstrates that the highest level of PC mRNA is found in liver corresponding to this tissue's high level of PC activity. Based on homology with other biotin-containing proteins, the ATP, pyruvate, and biotin-binding sites can be identified. One of two patients with documented PC deficiency was found to be missing PC mRNA, further confirming the identity of this cDNA.
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Affiliation(s)
- I D Wexler
- Department of Biochemistry, Case Western Reserve University School of Medicine, Rainbow Babies and Childrens Hospital, Cleveland, OH 44106
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Sola MM, Oliver FJ, Salto R, Gutiérrez M, Vargas A. Citrate inhibition of rat-kidney cortex phosphofructokinase. Mol Cell Biochem 1994; 135:123-8. [PMID: 7838139 DOI: 10.1007/bf00926514] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The regulatory properties of citrate on the activity of phosphofructokinase (PFK) purified from rat-kidney cortex has been studied. Citrate produces increases in the K0.5 for Fru-6-P and in the Hill coefficient as well as a decrease in the Vmax of the reaction without affecting the kinetic parameters for ATP as substrate. ATP potentiates synergistically the effects of citrate as an inhibitor of the enzyme. Fru-2,6-P2 and AMP at concentrations equal to Ka were not able to completely prevent citrate inhibition of the enzyme. Physiological concentrations of ATP and citrate produce a strong inhibition of renal PFK suggesting that may participate in the control of glycolysis in vivo.
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Affiliation(s)
- M M Sola
- Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Granada, Spain
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Sola MM, Oliver FJ, Salto R, Gutiérrez M, Vargas AM. Regulation of rat-kidney cortex fructose-1,6-bisphosphatase activity. II. Effects of adenine nucleotides. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1993; 25:1969-74. [PMID: 8138036 DOI: 10.1016/0020-711x(88)90333-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1. The native rat-kidney cortex Fructose-1,6-bisphosphatase is differentially regulated by adenine nucleotides in the presence of divalent cations. 2. Binding of AMP and ADP to the enzyme is co-operative. The inhibition by both nucleotides show an uncompetitive mechanism AMP being the most efficient inhibitor. 3. Mg2+ decreases the inhibition produced by AMP and ADP by enhancing their I0.5 and completely annulates the inhibitory effect of ATP. 4. In the presence of Mn2+ ADP behaves as an inhibitor but no inhibition is evident with AMP, suggesting the existence of different allosteric sites for each nucleotide.
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Affiliation(s)
- M M Sola
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Granada, Spain
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Sola MM, Oliver FJ, Salto R, Gutiérrez M, Vargas AM. Regulation of rat-kidney cortex fructose-1,6-bisphosphatase activity. I. Effects of fructose-2,6-bisphosphate and divalent cations. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1993; 25:1963-8. [PMID: 8138035 DOI: 10.1016/0020-711x(88)90332-1] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
1. The native rat-kidney cortex Fructose-1,6-BPase is differentially regulated by Mg2+ and Mn2+. 2. Mg2+ binding to the enzyme is hyperbolic and large concentrations of the cation are non-inhibitory. 3. Mn2+ produces a 10-fold rise in Vmax higher than Mg2+. [Mn2+]0.5 is much larger than [Mg2+]0.5. At elevated [Mn2+] inhibition is observed. 4. Mg2+ and Mn2+ produce antagonistic effects on the inhibition of the enzyme by high substrate. 5. Fru-2,6-P2 inhibits the enzyme by rising the S0.5 and favouring a sigmoidal kinetics. 6. The inhibition by Fru-2,6-P2 is released by Mg2+ and more powerfully by Mn2+ increasing the I0.5.
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Affiliation(s)
- M M Sola
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias, Universidad de Granada, Spain
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Sola M, Salto R, Oliver F, Gutiérrez M, Vargas A. Effects of AMP and fructose 2,6-bisphosphate on fluxes between glucose 6-phosphate and triose-phosphate in renal cortical extracts. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)36521-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Gonzalez-Flecha B, Evelson P, Sterin-Speziale N, Boveris A. Hydrogen peroxide metabolism and oxidative stress in cortical, medullary and papillary zones of rat kidney. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1157:155-61. [PMID: 8507651 DOI: 10.1016/0304-4165(93)90059-h] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The cortical, medullary and papillary regions of rat kidney were evaluated for a series of parameters related to hydrogen peroxide metabolism and oxidative stress. The rates of oxygen uptake, prostaglandin synthesis and malondialdehyde production by kidney slices were: 47, 0.003 and 0.051 mumol/h g wet wt., respectively, in cortex, 32, 0.023 and 0.035 in medulla and 22, 0.034 and 0.007 in papilla. The activities of superoxide dismutase, catalase and glutathione peroxidase were: 144 +/- 16 U/g wet wt., 880 +/- 100 pmol/g wet wt. and 177 +/- 16 U/g wet wt. in cortex; 97 +/- 9 U/g wet wt., 550 +/- 50 pmol/g wet wt. and 142 +/- 18 U/g wet wt. in medulla; and 23 +/- 2 U/g wet wt., 90 +/- 9 pmol/g wet wt. and 147 +/- 5 U/g wet wt. in papilla. Hydrogen peroxide steady-state concentrations were 0.09 +/- 0.01, 0.07 +/- 0.01 and 0.08 +/- 0.01 microM whereas alpha-tocopherol content was 21 +/- 2, 23 +/- 1 and 34 +/- 3 mumol/g wet wt. and hydroperoxide-initiated chemiluminescence was 22 +/- 2, 33 +/- 2 and 14 +/- 1 cpm. 10(-3)/mg prot for cortex, medulla and papilla, respectively. After 60 min ischemia-30 min reperfusion hydroperoxide-initiated chemiluminescence and hydrogen peroxide steady-state concentration increased by 30% and 60% in cortex and 80% and 60% in medulla, whereas alpha-tocopherol content decreased by 30%, 50% and 2% in cortex, medulla and papilla, respectively. The reperfusion/control ratio of hydroperoxide-initiated chemiluminescence and hydrogen peroxide steady-state concentrations in cortex and medulla indicate the occurrence of oxidative stress after ischemia-reperfusion. The lower sensitivity to oxidative stress found in papilla could be explained by the relatively high relationship of alpha-tocopherol content to hydrogen peroxide production rate in this sub-organ.
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Affiliation(s)
- B Gonzalez-Flecha
- Instituto de Quimica y Fisicoquimica Biologicas, Facultad de Farmacia y Bioquimica, Universidad de Buenos Aires, Argentina
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Chin E, Zhou J, Bondy C. Anatomical and developmental patterns of facilitative glucose transporter gene expression in the rat kidney. J Clin Invest 1993; 91:1810-5. [PMID: 8473519 PMCID: PMC288162 DOI: 10.1172/jci116392] [Citation(s) in RCA: 55] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
In situ hybridization was used to map cellular patterns of gene expression for facilitative glucose transporters (GTs) 1-5 in the developing and adult rat kidney. GT3 was not detected. GT1 mRNA was present in the proximal straight tubule (PST), distal nephron and collecting duct. GT2 mRNA was localized in both proximal convoluted and PST, while GT5 mRNA was detected only in the PST. GT4 mRNA and immunoreactivity were focally localized in the thick ascending limb of Henle's loop and were coexpressed with IGF-I. Thus, each of the four different isoforms demonstrated a distinct renal distribution, with GTs 1, 2, and 5 coexpressed in the PST. Renal GT1 and GT5 gene expression were unchanged throughout development, while GT2 was most abundant before weaning and GT4 was first detected after weaning. Only GT4 appeared to be hormonally regulated: It was decreased after hypophysectomy and increased after vasopressin treatment, but was not affected by 1 or 4 d of insulinopenic diabetes mellitus. The coexpression of GT4 and IGF-I in the thick ascending limb segment of the nephron suggests a novel autocrine/paracrine mechanism by which cells may control local fuel economy independently from that of the larger structure to which they belong and from the systemic hormonal milieu.
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Affiliation(s)
- E Chin
- Developmental Endocrinology Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892
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