1
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Beltran AS. Novel Approaches to Studying SLC13A5 Disease. Metabolites 2024; 14:84. [PMID: 38392976 PMCID: PMC10890222 DOI: 10.3390/metabo14020084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Revised: 01/17/2024] [Accepted: 01/18/2024] [Indexed: 02/25/2024] Open
Abstract
The role of the sodium citrate transporter (NaCT) SLC13A5 is multifaceted and context-dependent. While aberrant dysfunction leads to neonatal epilepsy, its therapeutic inhibition protects against metabolic disease. Notably, insights regarding the cellular and molecular mechanisms underlying these phenomena are limited due to the intricacy and complexity of the latent human physiology, which is poorly captured by existing animal models. This review explores innovative technologies aimed at bridging such a knowledge gap. First, I provide an overview of SLC13A5 variants in the context of human disease and the specific cell types where the expression of the transporter has been observed. Next, I discuss current technologies for generating patient-specific induced pluripotent stem cells (iPSCs) and their inherent advantages and limitations, followed by a summary of the methods for differentiating iPSCs into neurons, hepatocytes, and organoids. Finally, I explore the relevance of these cellular models as platforms for delving into the intricate molecular and cellular mechanisms underlying SLC13A5-related disorders.
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Affiliation(s)
- Adriana S Beltran
- Department of Genetics, University of North Carolina, Chapel Hill, NC 27599, USA
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2
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Icard P, Simula L, Zahn G, Alifano M, Mycielska ME. The dual role of citrate in cancer. Biochim Biophys Acta Rev Cancer 2023; 1878:188987. [PMID: 37717858 DOI: 10.1016/j.bbcan.2023.188987] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Revised: 09/04/2023] [Accepted: 09/07/2023] [Indexed: 09/19/2023]
Abstract
Citrate is a key metabolite of the Krebs cycle that can also be exported in the cytosol, where it performs several functions. In normal cells, citrate sustains protein acetylation, lipid synthesis, gluconeogenesis, insulin secretion, bone tissues formation, spermatozoid mobility, and immune response. Dysregulation of citrate metabolism is implicated in several pathologies, including cancer. Here we discuss how cancer cells use citrate to sustain their proliferation, survival, and metastatic progression. Also, we propose two paradoxically opposite strategies to reduce tumour growth by targeting citrate metabolism in preclinical models. In the first strategy, we propose to administer in the tumor microenvironment a high amount of citrate, which can then act as a glycolysis inhibitor and apoptosis inducer, whereas the other strategy targets citrate transporters to starve cancer cells from citrate. These strategies, effective in several preclinical in vitro and in vivo cancer models, could be exploited in clinics, particularly to increase sensibility to current anti-cancer agents.
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Affiliation(s)
- Philippe Icard
- Normandie Univ, UNICAEN, INSERM U1086 Interdisciplinary Research Unit for Cancer Prevention and Treatment, Caen, France; Service of Thoracic Surgery, Cochin Hospital, AP-, HP, 75014, Paris, France.
| | - Luca Simula
- Cochin Institute, INSERM U1016, CNRS UMR8104, University of Paris-Cité, Paris 75014, France
| | | | - Marco Alifano
- Service of Thoracic Surgery, Cochin Hospital, AP-, HP, 75014, Paris, France; INSERM U1138, Integrative Cancer Immunology, University of Paris, 75006 Paris, France
| | - Maria E Mycielska
- Department of Structural Biology, Institute of Biophysics and Physical Biochemistry, University of Regensburg, 93053 Regensburg, Germany
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3
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Du X, Cui Z, Zhang R, Zhao K, Wang L, Yao J, Liu S, Cai C, Cao Y. The Effects of Rumen-Protected Choline and Rumen-Protected Nicotinamide on Liver Transcriptomics in Periparturient Dairy Cows. Metabolites 2023; 13:metabo13050594. [PMID: 37233635 DOI: 10.3390/metabo13050594] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Revised: 04/17/2023] [Accepted: 04/24/2023] [Indexed: 05/27/2023] Open
Abstract
To investigate the effects of rumen-protected choline (RPC) and rumen-protected nicotinamide (RPM) on liver metabolic function based on transcriptome in periparturient dairy cows, 10 healthy Holstein dairy cows with similar parity were allocated to RPC and RPM groups (n = 5). The cows were fed experimental diets between 14 days before and 21 days after parturition. The RPC diet contained 60 g RPC per day, and the RPM diet contained 18.7 g RPM per day. Liver biopsies were taken 21 days after calving for the transcriptome analysis. A model of fat deposition hepatocytes was constructed using the LO2 cell line with the addition of NEFA (1.6 mmol/L), and the expression level of genes closely related to liver metabolism was validated and divided into a CHO group (75 μmol/L) and a NAM group (2 mmol/L). The results showed that the expression of a total of 11,023 genes was detected and clustered obviously between the RPC and RPM groups. These genes were assigned to 852 Gene Ontology terms, the majority of which were associated with biological process and molecular function. A total of 1123 differentially expressed genes (DEGs), 640 up-regulated and 483 down-regulated, were identified between the RPC and RPM groups. These DEGs were mainly correlated with fat metabolism, oxidative stress and some inflammatory pathways. In addition, compared with the NAM group, the gene expression level of FGF21, CYP26A1, SLC13A5, SLCO1B3, FBP2, MARS1 and CDH11 in the CHO group increased significantly (p < 0.05). We proposed that that RPC could play a prominent role in the liver metabolism of periparturient dairy cows by regulating metabolic processes such as fatty acid synthesis and metabolism and glucose metabolism; yet, RPM was more involved in biological processes such as the TCA cycle, ATP generation and inflammatory signaling.
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Affiliation(s)
- Xue'er Du
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
| | - Zhijie Cui
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
| | - Rui Zhang
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
| | - Keliang Zhao
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
| | - Lamei Wang
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
| | - Junhu Yao
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
| | - Shimin Liu
- UWA Institute of Agriculture, The University of Western Australia, Crawley, WA 6009, Australia
| | - Chuanjiang Cai
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
| | - Yangchun Cao
- College of Animal Science and Technology, Northwest A&F University, Xianyang 712100, China
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4
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Mapping the Metabolic Niche of Citrate Metabolism and SLC13A5. Metabolites 2023; 13:metabo13030331. [PMID: 36984771 PMCID: PMC10054676 DOI: 10.3390/metabo13030331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 02/17/2023] [Accepted: 02/20/2023] [Indexed: 02/26/2023] Open
Abstract
The small molecule citrate is a key molecule that is synthesized de novo and involved in diverse biochemical pathways influencing cell metabolism and function. Citrate is highly abundant in the circulation, and cells take up extracellular citrate via the sodium-dependent plasma membrane transporter NaCT encoded by the SLC13A5 gene. Citrate is critical to maintaining metabolic homeostasis and impaired NaCT activity is implicated in metabolic disorders. Though citrate is one of the best known and most studied metabolites in humans, little is known about the consequences of altered citrate uptake and metabolism. Here, we review recent findings on SLC13A5, NaCT, and citrate metabolism and discuss the effects on metabolic homeostasis and SLC13A5-dependent phenotypes. We discuss the “multiple-hit theory” and how stress factors induce metabolic reprogramming that may synergize with impaired NaCT activity to alter cell fate and function. Furthermore, we underline how citrate metabolism and compartmentalization can be quantified by combining mass spectrometry and tracing approaches. We also discuss species-specific differences and potential therapeutic implications of SLC13A5 and NaCT. Understanding the synergistic impact of multiple stress factors on citrate metabolism may help to decipher the disease mechanisms associated with SLC13A5 citrate transport disorders.
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5
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Mishra D, Kannan K, Meadows K, Macro J, Li M, Frankel S, Rogina B. INDY-From Flies to Worms, Mice, Rats, Non-Human Primates, and Humans. FRONTIERS IN AGING 2022; 2:782162. [PMID: 35822025 PMCID: PMC9261455 DOI: 10.3389/fragi.2021.782162] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Accepted: 11/24/2021] [Indexed: 01/17/2023]
Abstract
I’m Not Dead Yet (Indy) is a fly homologue of the mammalian SLC13A5 (mSLC13A5) plasma membrane citrate transporter, a key metabolic regulator and energy sensor involved in health, longevity, and disease. Reduction of Indy gene activity in flies, and its homologs in worms, modulates metabolism and extends longevity. The metabolic changes are similar to what is obtained with caloric restriction (dietary restriction). Similar effects on metabolism have been observed in mice and rats. As a citrate transporter, INDY regulates cytoplasmic citrate levels. Indy flies heterozygous for a P-element insertion have increased spontaneous physical activity, increased fecundity, reduced insulin signaling, increased mitochondrial biogenesis, preserved intestinal stem cell homeostasis, lower lipid levels, and increased stress resistance. Mammalian Indy knockout (mIndy-KO) mice have higher sensitivity to insulin signaling, lower blood pressure and heart rate, preserved memory and are protected from the negative effects of a high-fat diet and some of the negative effects of aging. Reducing mIndy expression in human hepatocarcinoma cells has recently been shown to inhibit cell proliferation. Reduced Indy expression in the fly intestine affects intestinal stem cell proliferation, and has recently been shown to also inhibit germ cell proliferation in males with delayed sperm maturation and decreased spermatocyte numbers. These results highlight a new connection between energy metabolism and cell proliferation. The overrall picture in a variety of species points to a conserved role of INDY for metabolism and health. This is illustrated by an association of high mIndy gene expression with non-alcoholic fatty liver disease in obese humans. mIndy (mSLC13A5) coding region mutations (e.g., loss-of-function) are also associated with adverse effects in humans, such as autosomal recessive early infantile epileptic encephalopathy and Kohlschütter−Tönz syndrome. The recent findings illustrate the importance of mIndy gene for human health and disease. Furthermore, recent work on small-molecule regulators of INDY highlights the promise of INDY-based treatments for ameliorating disease and promoting healthy aging.
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Affiliation(s)
- Dushyant Mishra
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT, United States
| | - Kavitha Kannan
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT, United States
| | - Kali Meadows
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT, United States
| | - Jacob Macro
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT, United States
| | - Michael Li
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT, United States
| | - Stewart Frankel
- Department of Biology, University of Hartford, West Hartford, CT, United States
| | - Blanka Rogina
- Department of Genetics and Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT, United States.,Institute for Systems Genomics, School of Medicine, University of Connecticut Health Center, Farmington, CT, United States
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6
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Pesta D, Jordan J. INDY as a Therapeutic Target for Cardio-Metabolic Disease. Metabolites 2022; 12:metabo12030244. [PMID: 35323687 PMCID: PMC8949283 DOI: 10.3390/metabo12030244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 03/01/2022] [Accepted: 03/07/2022] [Indexed: 12/04/2022] Open
Abstract
Decreased expression of the plasma membrane citrate transporter INDY (acronym I’m Not Dead, Yet) promotes longevity and protects from high-fat diet- and aging-induced metabolic derangements. Preventing citrate import into hepatocytes by different strategies can reduce hepatic triglyceride accumulation and improve hepatic insulin sensitivity, even in the absence of effects on body composition. These beneficial effects likely derive from decreased hepatic de novo fatty acid biosynthesis as a result of reduced cytoplasmic citrate levels. While in vivo and in vitro studies show that inhibition of INDY prevents intracellular lipid accumulation, body weight is not affected by organ-specific INDY inhibition. Besides these beneficial metabolic effects, INDY inhibition may also improve blood pressure control through sympathetic nervous system inhibition, partly via reduced peripheral catecholamine synthesis. These effects make INDY a promising candidate with bidirectional benefits for improving both metabolic disease and blood pressure control.
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Affiliation(s)
- Dominik Pesta
- German Aerospace Center (DLR), Institute of Aerospace Medicine, D-51147 Cologne, Germany;
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, D-50931 Cologne, Germany
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, D-50931 Cologne, Germany
- Correspondence:
| | - Jens Jordan
- German Aerospace Center (DLR), Institute of Aerospace Medicine, D-51147 Cologne, Germany;
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7
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Li Z, Li L, Heyward S, Men S, Xu M, Sueyoshi T, Wang H. Phenobarbital Induces SLC13A5 Expression through Activation of PXR but Not CAR in Human Primary Hepatocytes. Cells 2021; 10:cells10123381. [PMID: 34943889 PMCID: PMC8699749 DOI: 10.3390/cells10123381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Revised: 11/26/2021] [Accepted: 11/29/2021] [Indexed: 02/05/2023] Open
Abstract
Phenobarbital (PB), a widely used antiepileptic drug, is known to upregulate the expression of numerous drug-metabolizing enzymes and transporters in the liver primarily via activation of the constitutive androstane receptor (CAR, NR1I3). The solute carrier family 13 member 5 (SLC13A5), a sodium-coupled citrate transporter, plays an important role in intracellular citrate homeostasis that is associated with a number of metabolic syndromes and neurological disorders. Here, we show that PB markedly elevates the expression of SLC13A5 through a pregnane X receptor (PXR)-dependent but CAR-independent signaling pathway. In human primary hepatocytes, the mRNA and protein expression of SLC13A5 was robustly induced by PB treatment, while genetic knockdown or pharmacological inhibition of PXR significantly attenuated this induction. Utilizing genetically modified HepaRG cells, we found that PB induces SLC13A5 expression in both wild type and CAR-knockout HepaRG cells, whereas such induction was fully abolished in the PXR-knockout HepaRG cells. Mechanistically, we identified and functionally characterized three enhancer modules located upstream from the transcription start site or introns of the SLC13A5 gene that are associated with the regulation of PXR-mediated SLC13A5 induction. Moreover, metformin, a deactivator of PXR, dramatically suppressed PB-mediated induction of hepatic SLC13A5 as well as its activation of the SLC13A5 luciferase reporter activity via PXR. Collectively, these data reveal PB as a potent inducer of SLC13A5 through the activation of PXR but not CAR in human primary hepatocytes.
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Affiliation(s)
- Zhihui Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
| | - Linhao Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
| | - Scott Heyward
- BioIVT, 1450 S Rolling Road, Halethorpe, MD 21227, USA;
| | - Shuaiqian Men
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
| | - Meishu Xu
- Department of Pharmaceutical Sciences, University of Pittsburgh, Pittsburgh, PA 15261, USA;
| | - Tatsuya Sueyoshi
- Pharmacogenetics Section, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709, USA;
| | - Hongbing Wang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, 20 Penn Street, Baltimore, MD 21201, USA; (Z.L.); (L.L.); (S.M.)
- Correspondence: ; Tel.: +1-410-706-1280
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8
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Jeong J, Lee J, Kim JH, Lim C. Metabolic flux from the Krebs cycle to glutamate transmission tunes a neural brake on seizure onset. PLoS Genet 2021; 17:e1009871. [PMID: 34714823 PMCID: PMC8555787 DOI: 10.1371/journal.pgen.1009871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 10/11/2021] [Indexed: 01/18/2023] Open
Abstract
Kohlschütter-Tönz syndrome (KTS) manifests as neurological dysfunctions, including early-onset seizures. Mutations in the citrate transporter SLC13A5 are associated with KTS, yet their underlying mechanisms remain elusive. Here, we report that a Drosophila SLC13A5 homolog, I'm not dead yet (Indy), constitutes a neurometabolic pathway that suppresses seizure. Loss of Indy function in glutamatergic neurons caused "bang-induced" seizure-like behaviors. In fact, glutamate biosynthesis from the citric acid cycle was limiting in Indy mutants for seizure-suppressing glutamate transmission. Oral administration of the rate-limiting α-ketoglutarate in the metabolic pathway rescued low glutamate levels in Indy mutants and ameliorated their seizure-like behaviors. This metabolic control of the seizure susceptibility was mapped to a pair of glutamatergic neurons, reversible by optogenetic controls of their activity, and further relayed onto fan-shaped body neurons via the ionotropic glutamate receptors. Accordingly, our findings reveal a micro-circuit that links neural metabolism to seizure, providing important clues to KTS-associated neurodevelopmental deficits.
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Affiliation(s)
- Jiwon Jeong
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Jongbin Lee
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Ji-hyung Kim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
| | - Chunghun Lim
- Department of Biological Sciences, Ulsan National Institute of Science and Technology, Ulsan, Republic of Korea
- * E-mail:
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Kannan K, Rogina B. The Role of Citrate Transporter INDY in Metabolism and Stem Cell Homeostasis. Metabolites 2021; 11:705. [PMID: 34677421 PMCID: PMC8540898 DOI: 10.3390/metabo11100705] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 10/05/2021] [Accepted: 10/12/2021] [Indexed: 12/11/2022] Open
Abstract
I'm Not Dead Yet (Indy) is a fly gene that encodes a homologue of mammalian SLC13A5 plasma membrane citrate transporter. Reducing expression of Indy gene in flies, and its homologues in worms, extends longevity. Indy reduction in flies, worms, mice and rats affects metabolism by regulating the levels of cytoplasmic citrate, inducing a state similar to calorie restriction. Changes include lower lipid levels, increased insulin sensitivity, increased mitochondrial biogenesis, and prevention of weight gain, among others. The INDY protein is predominantly expressed in fly metabolic tissues: the midgut, fat body and oenocytes. Changes in fly midgut metabolism associated with reduced Indy gene activity lead to preserved mitochondrial function and reduced production of reactive oxygen species. All these changes lead to preserved intestinal stem cell homeostasis, which has a key role in maintaining intestinal epithelium function and enhancing fly healthspan and lifespan. Indy gene expression levels change in response to caloric content of the diet, inflammation and aging, suggesting that INDY regulates metabolic adaptation to nutrition or energetic requirements by controlling citrate levels.
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Affiliation(s)
- Kavitha Kannan
- Department of Genetics & Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT 06030, USA;
| | - Blanka Rogina
- Department of Genetics & Genome Sciences, School of Medicine, University of Connecticut Health Center, Farmington, CT 06030, USA;
- Institute for Systems Genomics, School of Medicine, University of Connecticut Health Center, Farmington, CT 06030, USA
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10
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Molecular Mechanisms of the SLC13A5 Gene Transcription. Metabolites 2021; 11:metabo11100706. [PMID: 34677420 PMCID: PMC8537064 DOI: 10.3390/metabo11100706] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 10/12/2021] [Accepted: 10/13/2021] [Indexed: 12/02/2022] Open
Abstract
Citrate is a crucial energy sensor that plays a central role in cellular metabolic homeostasis. The solute carrier family 13 member 5 (SLC13A5), a sodium-coupled citrate transporter highly expressed in the mammalian liver with relatively low levels in the testis and brain, imports citrate from extracellular spaces into the cells. The perturbation of SLC13A5 expression and/or activity is associated with non-alcoholic fatty liver disease, obesity, insulin resistance, cell proliferation, and early infantile epileptic encephalopathy. SLC13A5 has been proposed as a promising therapeutic target for the treatment of these metabolic disorders. In the liver, the inductive expression of SLC13A5 has been linked to several xenobiotic receptors such as the pregnane X receptor and the aryl hydrocarbon receptor as well as certain hormonal and nutritional stimuli. Nevertheless, in comparison to the heightened interest in understanding the biological function and clinical relevance of SLC13A5, studies focusing on the regulatory mechanisms of SLC13A5 expression are relatively limited. In this review, we discuss the current advances in our understanding of the molecular mechanisms by which the expression of SLC13A5 is regulated. We expect this review will provide greater insights into the regulation of the SLC13A5 gene transcription and the signaling pathways involved therein.
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Hu W, Zhang D, Tu H, Li YL. Reduced Cell Excitability of Cardiac Postganglionic Parasympathetic Neurons Correlates With Myocardial Infarction-Induced Fatal Ventricular Arrhythmias in Type 2 Diabetes Mellitus. Front Neurosci 2021; 15:721364. [PMID: 34483832 PMCID: PMC8416412 DOI: 10.3389/fnins.2021.721364] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Accepted: 07/30/2021] [Indexed: 01/09/2023] Open
Abstract
Objective Withdrawal of cardiac vagal activity is considered as one of the important triggers for acute myocardial infarction (MI)-induced ventricular arrhythmias in type 2 diabetes mellitus (T2DM). Our previous study demonstrated that cell excitability of cardiac parasympathetic postganglionic (CPP) neurons was reduced in T2DM rats. This study investigated whether cell excitability of CPP neurons is associated with cardiac vagal activity and MI-induced ventricular arrhythmias in T2DM rats. Methods Rat T2DM was induced by a high-fat diet plus streptozotocin injection. MI-evoked ventricular arrhythmia was achieved by surgical ligation of the left anterior descending coronary artery. Twenty-four-hour, continuous ECG recording was used to quantify ventricular arrhythmic events and heart rate variability (HRV) in conscious rats. The power spectral analysis of HRV was used to evaluate autonomic function. Cell excitability of CPP neurons was measured by the whole-cell patch-clamp technique. Results Twenty-four-hour ECG data demonstrated that MI-evoked fatal ventricular arrhythmias are more severe in T2DM rats than that in sham rats. In addition, the Kaplan-Meier analysis demonstrated that the survival rate over 2 weeks after MI is significantly lower in T2DM rats (15% in T2DM+MI) compared to sham rats (75% in sham+MI). The susceptibility to ventricular tachyarrhythmia elicited by programmed electrical stimulation was higher in anesthetized T2DM+MI rats than that in rats with MI or T2DM alone (7.0 ± 0.58 in T2DM+MI group vs. 3.5 ± 0.76 in sham+MI). Moreover, as an index for vagal control of ventricular function, changes of left ventricular systolic pressure (LVSP) and the maximum rate of increase of left ventricular pressure (LV dP/dtmax) in response to vagal efferent nerve stimulation were blunted in T2DM rats. Furthermore, T2DM increased heterogeneity of ventricular electrical activities and reduced cardiac parasympathetic activity and cell excitability of CPP neurons (current threshold-inducing action potentials being 62 ± 3.3 pA in T2DM rats without MI vs. 27 ± 1.9 pA in sham rats without MI). However, MI did not alter vagal control of the ventricular function and CPP neuronal excitability, although it also induced cardiac autonomic dysfunction and enhanced heterogeneity of ventricular electrical activities. Conclusion The reduction of CPP neuron excitability is involved in decreased cardiac vagal function, including cardiac parasympathetic activity and vagal control of ventricular function, which is associated with MI-induced high mortality and malignant ventricular arrhythmias in T2DM.
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Affiliation(s)
- Wenfeng Hu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Dongze Zhang
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Huiyin Tu
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States
| | - Yu-Long Li
- Department of Emergency Medicine, University of Nebraska Medical Center, Omaha, NE, United States.,Department of Cellular & Integrative Physiology, University of Nebraska Medical Center, Omaha, NE, United States
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12
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Schumann T, König J, von Loeffelholz C, Vatner DF, Zhang D, Perry RJ, Bernier M, Chami J, Henke C, Kurzbach A, El-Agroudy NN, Willmes DM, Pesta D, de Cabo R, O Sullivan JF, Simon E, Shulman GI, Hamilton BS, Birkenfeld AL. Deletion of the diabetes candidate gene Slc16a13 in mice attenuates diet-induced ectopic lipid accumulation and insulin resistance. Commun Biol 2021; 4:826. [PMID: 34211098 PMCID: PMC8249653 DOI: 10.1038/s42003-021-02279-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 05/20/2021] [Indexed: 12/12/2022] Open
Abstract
Genome-wide association studies have identified SLC16A13 as a novel susceptibility gene for type 2 diabetes. The SLC16A13 gene encodes SLC16A13/MCT13, a member of the solute carrier 16 family of monocarboxylate transporters. Despite its potential importance to diabetes development, the physiological function of SLC16A13 is unknown. Here, we validate Slc16a13 as a lactate transporter expressed at the plasma membrane and report on the effect of Slc16a13 deletion in a mouse model. We show that Slc16a13 increases mitochondrial respiration in the liver, leading to reduced hepatic lipid accumulation and increased hepatic insulin sensitivity in high-fat diet fed Slc16a13 knockout mice. We propose a mechanism for improved hepatic insulin sensitivity in the context of Slc16a13 deficiency in which reduced intrahepatocellular lactate availability drives increased AMPK activation and increased mitochondrial respiration, while reducing hepatic lipid content. Slc16a13 deficiency thereby attenuates hepatic diacylglycerol-PKCε mediated insulin resistance in obese mice. Together, these data suggest that SLC16A13 is a potential target for the treatment of type 2 diabetes and non-alcoholic fatty liver disease.
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Affiliation(s)
- Tina Schumann
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Jörg König
- Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | | | - Daniel F Vatner
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Dongyan Zhang
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
| | - Rachel J Perry
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Michel Bernier
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Jason Chami
- Heart Research Institute, Newtown, NSW, Australia
| | - Christine Henke
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Anica Kurzbach
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Nermeen N El-Agroudy
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Diana M Willmes
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany
- Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine, Technische Universität Dresden, Dresden, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Dominik Pesta
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Centre for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Cologne, Germany
- Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Rafael de Cabo
- Experimental Gerontology Section, Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - John F O Sullivan
- Heart Research Institute, Newtown, NSW, Australia
- Charles Perkins Centre, The University of Sydney, Camperdown, NSW, Australia
- Department of Cardiology, Royal Prince Alfred Hospital, Camperdown, NSW, Australia
| | - Eric Simon
- Computational Biology, Boehringer-Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA
- Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
| | - Bradford S Hamilton
- CardioMetabolic Diseases Research, Boehringer-Ingelheim Pharma GmbH & Co. KG, Biberach an der Riss, Germany
| | - Andreas L Birkenfeld
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
- King's College London, Department of Diabetes, School of Life Course Science, London, UK.
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany.
- Department of Endocrinology, Diabetology and Nephrology, University Hospital of Tübingen, Tübingen, Germany.
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Consequences of NaCT/SLC13A5/mINDY deficiency: good versus evil, separated only by the blood-brain barrier. Biochem J 2021; 478:463-486. [PMID: 33544126 PMCID: PMC7868109 DOI: 10.1042/bcj20200877] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 01/07/2021] [Accepted: 01/11/2021] [Indexed: 02/08/2023]
Abstract
NaCT/SLC13A5 is a Na+-coupled transporter for citrate in hepatocytes, neurons, and testes. It is also called mINDY (mammalian ortholog of ‘I'm Not Dead Yet’ in Drosophila). Deletion of Slc13a5 in mice leads to an advantageous phenotype, protecting against diet-induced obesity, and diabetes. In contrast, loss-of-function mutations in SLC13A5 in humans cause a severe disease, EIEE25/DEE25 (early infantile epileptic encephalopathy-25/developmental epileptic encephalopathy-25). The difference between mice and humans in the consequences of the transporter deficiency is intriguing but probably explainable by the species-specific differences in the functional features of the transporter. Mouse Slc13a5 is a low-capacity transporter, whereas human SLC13A5 is a high-capacity transporter, thus leading to quantitative differences in citrate entry into cells via the transporter. These findings raise doubts as to the utility of mouse models to evaluate NaCT biology in humans. NaCT-mediated citrate entry in the liver impacts fatty acid and cholesterol synthesis, fatty acid oxidation, glycolysis, and gluconeogenesis; in neurons, this process is essential for the synthesis of the neurotransmitters glutamate, GABA, and acetylcholine. Thus, SLC13A5 deficiency protects against obesity and diabetes based on what the transporter does in hepatocytes, but leads to severe brain deficits based on what the transporter does in neurons. These beneficial versus detrimental effects of SLC13A5 deficiency are separable only by the blood-brain barrier. Can we harness the beneficial effects of SLC13A5 deficiency without the detrimental effects? In theory, this should be feasible with selective inhibitors of NaCT, which work only in the liver and do not get across the blood-brain barrier.
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Schumann T, König J, Henke C, Willmes DM, Bornstein SR, Jordan J, Fromm MF, Birkenfeld AL. Solute Carrier Transporters as Potential Targets for the Treatment of Metabolic Disease. Pharmacol Rev 2020; 72:343-379. [PMID: 31882442 DOI: 10.1124/pr.118.015735] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The solute carrier (SLC) superfamily comprises more than 400 transport proteins mediating the influx and efflux of substances such as ions, nucleotides, and sugars across biological membranes. Over 80 SLC transporters have been linked to human diseases, including obesity and type 2 diabetes (T2D). This observation highlights the importance of SLCs for human (patho)physiology. Yet, only a small number of SLC proteins are validated drug targets. The most recent drug class approved for the treatment of T2D targets sodium-glucose cotransporter 2, product of the SLC5A2 gene. There is great interest in identifying other SLC transporters as potential targets for the treatment of metabolic diseases. Finding better treatments will prove essential in future years, given the enormous personal and socioeconomic burden posed by more than 500 million patients with T2D by 2040 worldwide. In this review, we summarize the evidence for SLC transporters as target structures in metabolic disease. To this end, we identified SLC13A5/sodium-coupled citrate transporter, and recent proof-of-concept studies confirm its therapeutic potential in T2D and nonalcoholic fatty liver disease. Further SLC transporters were linked in multiple genome-wide association studies to T2D or related metabolic disorders. In addition to presenting better-characterized potential therapeutic targets, we discuss the likely unnoticed link between other SLC transporters and metabolic disease. Recognition of their potential may promote research on these proteins for future medical management of human metabolic diseases such as obesity, fatty liver disease, and T2D. SIGNIFICANCE STATEMENT: Given the fact that the prevalence of human metabolic diseases such as obesity and type 2 diabetes has dramatically risen, pharmacological intervention will be a key future approach to managing their burden and reducing mortality. In this review, we present the evidence for solute carrier (SLC) genes associated with human metabolic diseases and discuss the potential of SLC transporters as therapeutic target structures.
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Affiliation(s)
- Tina Schumann
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
| | - Jörg König
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
| | - Christine Henke
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
| | - Diana M Willmes
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
| | - Stefan R Bornstein
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
| | - Jens Jordan
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
| | - Martin F Fromm
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
| | - Andreas L Birkenfeld
- Section of Metabolic and Vascular Medicine, Medical Clinic III, Dresden University School of Medicine (T.S., C.H., D.M.W., S.R.B.), and Paul Langerhans Institute Dresden of the Helmholtz Center Munich at University Hospital and Faculty of Medicine (T.S., C.H., D.M.W.), Technische Universität Dresden, Dresden, Germany; Deutsches Zentrum für Diabetesforschung e.V., Neuherberg, Germany (T.S., C.H., D.M.W., A.L.B.); Clinical Pharmacology and Clinical Toxicology, Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany (J.K., M.F.F.); Institute for Aerospace Medicine, German Aerospace Center and Chair for Aerospace Medicine, University of Cologne, Cologne, Germany (J.J.); Diabetes and Nutritional Sciences, King's College London, London, United Kingdom (S.R.B., A.L.B.); Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Tübingen, Germany (A.L.B.); and Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany (A.L.B.)
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Hu T, Huang W, Li Z, Kane MA, Zhang L, Huang SM, Wang H. Comparative proteomic analysis of SLC13A5 knockdown reveals elevated ketogenesis and enhanced cellular toxic response to chemotherapeutic agents in HepG2 cells. Toxicol Appl Pharmacol 2020; 402:115117. [PMID: 32634519 DOI: 10.1016/j.taap.2020.115117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2020] [Revised: 06/09/2020] [Accepted: 06/12/2020] [Indexed: 12/29/2022]
Abstract
Solute carrier family 13 member 5 (SLC13A5) is an uptake transporter mainly expressed in the liver and transports citrate from blood circulation into hepatocytes. Accumulating evidence suggests that SLC13A5 is involved in hepatic lipogenesis, cell proliferation, epilepsy, and bone development in mammals. However, the molecular mechanisms behind SLC13A5-mediated physiological/pathophysiological changes are largely unknown. In this regard, we conducted a differential proteome analysis in HepG2 and SLC13A5-knockdown (KD) HepG2 cells. A total of 3826 proteins were quantified and 330 proteins showed significant alterations (fold change ≥1.5; p < .05) in the knockdown cells. Gene ontology enrichment analysis reveals that 38 biological processes were significantly changed, with ketone body biosynthetic process showing the most significant upregulation following SLC13A5-KD. Catalytic activity and binding activity were the top two molecular functions associated with differentially expressed proteins, while HMG-CoA lyase activity showed the highest fold enrichment. Further ingenuity pathway analysis predicted 40 canonical pathways and 28 upstream regulators (p < .01), of which most were associated with metabolism, cell proliferation, and stress response. In line with these findings, functional validation demonstrated increased levels of two key ketone bodies, acetoacetate and β-hydroxybutyrate, in the SLC13A5-KD cells. Additional experiments showed that SLC13A5-KD sensitizes HepG2 cells to cellular stress caused by a number of chemotherapeutic agents. Together, our findings demonstrate that knockdown of SLC13A5 promotes hepatic ketogenesis and enhances cellular stress response in HepG2 cells, suggesting a potential role of this transporter in metabolic disorders and liver cancer.
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Affiliation(s)
- Tao Hu
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States of America
| | - Weiliang Huang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States of America
| | - Zhihui Li
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States of America
| | - Maureen A Kane
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States of America
| | - Lei Zhang
- Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD 20993, United States of America
| | - Shiew-Mei Huang
- Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, MD 20993, United States of America
| | - Hongbing Wang
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, MD 21201, United States of America.
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16
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The Hepatic Plasma Membrane Citrate Transporter NaCT (SLC13A5) as a Molecular Target for Metformin. Sci Rep 2020; 10:8536. [PMID: 32444674 PMCID: PMC7244496 DOI: 10.1038/s41598-020-65621-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2019] [Accepted: 04/23/2020] [Indexed: 12/17/2022] Open
Abstract
Metformin is the first-line treatment for type 2 diabetes. Inhibition of hepatic gluconeogenesis is the primary contributor to its anti-diabetic effect. Metformin inhibits complex I and α-glycerophosphate shuttle, and the resultant increase in cytoplasmic NADH/NAD+ ratio diverts glucose precursors away from gluconeogenesis. These actions depend on metformin-mediated activation of AMP kinase (AMPK). Here we report on a hitherto unknown mechanism. Metformin inhibits the expression of the plasma membrane citrate transporter NaCT in HepG2 cells and decreases cellular levels of citrate. 5-Aminoimidazole-4-carboxamide ribonucleotide (AICAR), an AMPK activator, elicits a similar effect. The process involves a decrease in maximal velocity with no change in substrate affinity. The decrease in NaCT expression is associated with decreased mRNA levels. AMPK inhibits mTOR, and the mTOR inhibitor rapamycin also decreases NaCT expression. The transcription factor downstream of AMPK that is relevant to cAMP signaling is CREB; decreased levels of phospho-CREB seem to mediate the observed effects of metformin on NaCT. Citrate is known to suppress glycolysis by inhibiting phosphofructokinase-1 and activate gluconeogenesis by stimulating fructose-1,6-bisphophatase; therefore, the decrease in cellular levels of citrate would stimulate glycolysis and inhibit gluconeogenesis. These studies uncover a novel mechanism for the anti-diabetic actions of metformin.
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Metabolic Biomarkers in Aging and Anti-Aging Research. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1178:247-264. [PMID: 31493231 DOI: 10.1007/978-3-030-25650-0_13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Although human life expectancy has increased significantly over the last two centuries, this has not been paralleled by a similar rise in healthy life expectancy. Thus, an important goal of anti-aging research has been to reduce the impact of age-associated diseases as a way of extending the human healthspan. This review will explore some of the potential avenues which have emerged from this research as the most promising strategies and drug targets for therapeutic interventions to promote healthy aging.
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Zhang T, Qi Z, Wang H, Ding S. Adeno-Associated Virus-Mediated Knockdown of SLC16A11 Improves Glucose Tolerance and Hepatic Insulin Signaling in High Fat Diet-Fed Mice. Exp Clin Endocrinol Diabetes 2019; 129:104-111. [PMID: 31185508 DOI: 10.1055/a-0840-3330] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND SLC16A11, a member of the SLC16 family, is associated with lipid metabolism, causing increased intracellular triacylglycerol (TAG) levels. In the current study, our primary goal was to determine if an SLC16A11 knockdown would improve glucose tolerance and hepatic insulin signaling in high fat diet (HFD)-fed mice. Additionally, the mechanism for exercise-improved insulin sensitivity remains unclear, and there is no mechanistic insight into SLC16A11's role in insulin sensitivity under exercise stress. Therefore, we also examined the impact of endurance exercise on the abundance of SLC16A11. METHODS C57BL/6 J male mice were fed either regular chow (Control) or HFD for 8 weeks and then injected with adeno-associated virus (AAV). Plasma parameters, tissue lipid contents, glucose tolerance, and expression profiles of hepatic insulin signaling were detected. Also, other mice were divided randomly into sedentary and exercise groups. We assessed hepatic expression of SLC16A11 after 8 weeks of endurance exercise. RESULTS 1) Hepatic SLC16A11 expression was greater in HFD-fed mice compared to Control mice. 2) AAV-mediated knockdown of SLC16A11 improved glucose tolerance, prevented TAG accumulation in serum and liver, and increased phosphorylation of protein kinase B (Akt) and glycogen synthesis kinase-3β (GSK3β) in HFD-fed mice. 3) Endurance exercise decreased hepatic SLC16A11 expression. CONCLUSIONS Inactivation of SLC16A11, which is robustly induced by HFD, improved glucose tolerance and hepatic insulin signaling, independent of body weight, but related to TAG. Additionally, SLC16A11 might mediate the health benefits of endurance exercise.
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Affiliation(s)
- Tan Zhang
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai, China.,College of Physical Education and Health, East China Normal University, Shanghai, China
| | - Zhengtang Qi
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai, China.,College of Physical Education and Health, East China Normal University, Shanghai, China
| | - Haiyan Wang
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai, China.,College of Physical Education and Health, East China Normal University, Shanghai, China
| | - Shuzhe Ding
- Key Laboratory of Adolescent Health Assessment and Exercise Intervention, Ministry of Education, East China Normal University, Shanghai, China.,College of Physical Education and Health, East China Normal University, Shanghai, China
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Willmes DM, Kurzbach A, Henke C, Schumann T, Zahn G, Heifetz A, Jordan J, Helfand SL, Birkenfeld AL. The longevity gene INDY ( I 'm N ot D ead Y et) in metabolic control: Potential as pharmacological target. Pharmacol Ther 2018; 185:1-11. [DOI: 10.1016/j.pharmthera.2017.10.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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von Loeffelholz C, Lieske S, Neuschäfer-Rube F, Willmes DM, Raschzok N, Sauer IM, König J, Fromm M, Horn P, Chatzigeorgiou A, Pathe-Neuschäfer-Rube A, Jordan J, Pfeiffer AFH, Mingrone G, Bornstein SR, Stroehle P, Harms C, Wunderlich FT, Helfand SL, Bernier M, de Cabo R, Shulman GI, Chavakis T, Püschel GP, Birkenfeld AL. The human longevity gene homolog INDY and interleukin-6 interact in hepatic lipid metabolism. Hepatology 2017; 66:616-630. [PMID: 28133767 PMCID: PMC5519435 DOI: 10.1002/hep.29089] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2016] [Revised: 12/15/2016] [Accepted: 01/19/2017] [Indexed: 12/17/2022]
Abstract
UNLABELLED Reduced expression of the Indy ("I am Not Dead, Yet") gene in lower organisms promotes longevity in a manner akin to caloric restriction. Deletion of the mammalian homolog of Indy (mIndy, Slc13a5) encoding for a plasma membrane-associated citrate transporter expressed highly in the liver, protects mice from high-fat diet-induced and aging-induced obesity and hepatic fat accumulation through a mechanism resembling caloric restriction. We studied a possible role of mIndy in human hepatic fat metabolism. In obese, insulin-resistant patients with nonalcoholic fatty liver disease, hepatic mIndy expression was increased and mIndy expression was also independently associated with hepatic steatosis. In nonhuman primates, a 2-year high-fat, high-sucrose diet increased hepatic mIndy expression. Liver microarray analysis showed that high mIndy expression was associated with pathways involved in hepatic lipid metabolism and immunological processes. Interleukin-6 (IL-6) was identified as a regulator of mIndy by binding to its cognate receptor. Studies in human primary hepatocytes confirmed that IL-6 markedly induced mIndy transcription through the IL-6 receptor and activation of the transcription factor signal transducer and activator of transcription 3, and a putative start site of the human mIndy promoter was determined. Activation of the IL-6-signal transducer and activator of transcription 3 pathway stimulated mIndy expression, enhanced cytoplasmic citrate influx, and augmented hepatic lipogenesis in vivo. In contrast, deletion of mIndy completely prevented the stimulating effect of IL-6 on citrate uptake and reduced hepatic lipogenesis. These data show that mIndy is increased in liver of obese humans and nonhuman primates with NALFD. Moreover, our data identify mIndy as a target gene of IL-6 and determine novel functions of IL-6 through mINDY. CONCLUSION Targeting human mINDY may have therapeutic potential in obese patients with nonalcoholic fatty liver disease. German Clinical Trials Register: DRKS00005450. (Hepatology 2017;66:616-630).
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Affiliation(s)
- Christian von Loeffelholz
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Friedrich Schiller University, and Department of Anesthesiology and Intensive Care, Jena University Hospital, Jena, 01774, Germany
| | - Stefanie Lieske
- Section of Metabolic Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Paul Langerhans Institute Dresden (PLID), TU Dresden,01307 Germany,Lehrstuhl für Biochemie der Ernährung, Universität Potsdam, Potsdam, 14558, Germany
| | | | - Diana M. Willmes
- Section of Metabolic Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Paul Langerhans Institute Dresden (PLID), TU Dresden,01307 Germany
| | - Nathanael Raschzok
- General, Visceral, and Transplantation Surgery, Charité – University School of Medicine, Berlin, 10117, Germany
| | - Igor M. Sauer
- General, Visceral, and Transplantation Surgery, Charité – University School of Medicine, Berlin, 10117, Germany
| | - Jörg König
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität, Erlangen-Nürnberg, 91054, Germany
| | - Martin Fromm
- Institute of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-Universität, Erlangen-Nürnberg, 91054, Germany
| | - Paul Horn
- Integrated Research and Treatment Center, Center for Sepsis Control and Care (CSCC), Friedrich Schiller University, and Department of Anesthesiology and Intensive Care, Jena University Hospital, Jena, 01774, Germany
| | - Antonis Chatzigeorgiou
- Department of Clinical Pathobiochemistry and Institute for Clinical Chemistry and Laboratory Medicine, University Clinic Dresden, TUD, Germany
| | | | - Jens Jordan
- Institute for Clinical Pharmacology, Hannover Medical School, 30625 Hannover, Germany
| | - Andreas F. H. Pfeiffer
- Department of Endocrinology, Diabetes and Nutrition, Charité – University School of Medicine, Berlin, 10117, Germany,German Centre for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Geltrude Mingrone
- Division of Diabetes & Nutritional Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE1 8WA, UK,Catholic University of Rome, Department of Internal Medicine, Rome, Italy
| | - Stefan R. Bornstein
- Section of Metabolic Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Paul Langerhans Institute Dresden (PLID), TU Dresden,01307 Germany,Division of Diabetes & Nutritional Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE1 8WA, UK,German Centre for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Peter Stroehle
- Max Planck Institute for Metabolism Research, Excellence cluster on cellular stress responses in aging associated diseases (CECAD), Cologne, 5093, Germany
| | - Christoph Harms
- Charité-Universitätsmedizin Berlin, Center for Stroke Research, Department of Experimental Neurology, Charitéplatz 1, 10117 Berlin, Germany
| | - F. Thomas Wunderlich
- Max Planck Institute for Metabolism Research, Excellence cluster on cellular stress responses in aging associated diseases (CECAD), Cologne, 5093, Germany
| | - Stephen. L. Helfand
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Michel Bernier
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
| | - Gerald I. Shulman
- Department of Internal Medicine, Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT 06520, USA
| | - Triantafyllos Chavakis
- Department of Clinical Pathobiochemistry and Institute for Clinical Chemistry and Laboratory Medicine, University Clinic Dresden, TUD, Germany
| | - Gerhard. P. Püschel
- Lehrstuhl für Biochemie der Ernährung, Universität Potsdam, Potsdam, 14558, Germany
| | - Andreas. L. Birkenfeld
- Section of Metabolic Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Paul Langerhans Institute Dresden (PLID), TU Dresden,01307 Germany,Division of Diabetes & Nutritional Sciences, Faculty of Life Sciences & Medicine, King’s College London, London SE1 8WA, UK,German Centre for Diabetes Research (DZD e.V.), Neuherberg, Germany,Competence Center for Metabolic Vascular Medicine, GWT-TU Dresden, Germany,Contact Information: Andreas L. Birkenfeld, M.D., Section of Metabolic Vascular Medicine, Dresden University School of Medicine Germany, TU Dresden, Tel: +49 15119188884.
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21
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Rives ML, Javitch JA, Wickenden AD. Potentiating SLC transporter activity: Emerging drug discovery opportunities. Biochem Pharmacol 2017; 135:1-11. [DOI: 10.1016/j.bcp.2017.02.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 02/13/2017] [Indexed: 12/12/2022]
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22
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Rogina B. INDY-A New Link to Metabolic Regulation in Animals and Humans. Front Genet 2017; 8:66. [PMID: 28596784 PMCID: PMC5442177 DOI: 10.3389/fgene.2017.00066] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 05/09/2017] [Indexed: 12/02/2022] Open
Abstract
The Indy (I’m Not Dead Yet) gene encodes the fly homolog of the mammalian SLC13A5 citrate transporter. Reduced expression of the Indy gene in flies and worms extends their longevity. INDY is expressed in the plasma membrane of metabolically active tissues. Decreased expression of Indy in worms, flies, mice, and rats alters metabolism in a manner similar to calorie restriction. Reducing INDY activity prevents weight gain in flies, worms, and mice, and counteracts the negative effects of age or a high fat diet on metabolism and insulin sensitivity. The metabolic effects of reducing INDY activity are the result of reduced cytoplasmic citrate. Citrate is a key metabolite and has a central role in energy status of the cell by effecting lipid and carbohydrate metabolism and energy production. Thereby newly described drugs that reduce INDY transporting activity increase insulin sensitivity and reduce hepatic lipid levels via its effect on hepatic citrate uptake. A recent report presented the first direct link between increased hepatic levels of human INDY, insulin resistance, and non-alcoholic fatty liver disease in obese humans. Similarly increased hepatic mIndy levels were observed in non-human primates fed on a high fat diet for 2 years. This effect is mediated via the stimulatory effect of the interleukin-6/Stat3 pathway on mINDY hepatic expression. These findings make INDY a potential and very promising target for the treatment of metabolic disorders in humans.
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Affiliation(s)
- Blanka Rogina
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, School of Medicine, University of Connecticut Health Center, FarmingtonCT, United States
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23
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Plasma Membrane Na⁺-Coupled Citrate Transporter (SLC13A5) and Neonatal Epileptic Encephalopathy. Molecules 2017; 22:molecules22030378. [PMID: 28264506 PMCID: PMC6155422 DOI: 10.3390/molecules22030378] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/24/2017] [Accepted: 02/25/2017] [Indexed: 12/30/2022] Open
Abstract
SLC13A5 is a Na+-coupled transporter for citrate that is expressed in the plasma membrane of specific cell types in the liver, testis, and brain. It is an electrogenic transporter with a Na+:citrate3− stoichiometry of 4:1. In humans, the Michaelis constant for SLC13A5 to transport citrate is ~600 μM, which is physiologically relevant given that the normal concentration of citrate in plasma is in the range of 150–200 μM. Li+ stimulates the transport function of human SLC13A5 at concentrations that are in the therapeutic range in patients on lithium therapy. Human SLC13A5 differs from rodent Slc13a5 in two important aspects: the affinity of the human transporter for citrate is ~30-fold less than that of the rodent transporter, thus making human SLC13A5 a low-affinity/high-capacity transporter and the rodent Slc13a5 a high-affinity/low-capacity transporter. In the liver, SLC13A5 is expressed exclusively in the sinusoidal membrane of the hepatocytes, where it plays a role in the uptake of circulating citrate from the sinusoidal blood for metabolic use. In the testis, the transporter is expressed only in spermatozoa, which is also only in the mid piece where mitochondria are located; the likely function of the transporter in spermatozoa is to mediate the uptake of citrate present at high levels in the seminal fluid for subsequent metabolism in the sperm mitochondria to generate biological energy, thereby supporting sperm motility. In the brain, the transporter is expressed mostly in neurons. As astrocytes secrete citrate into extracellular medium, the potential function of SLC13A5 in neurons is to mediate the uptake of circulating citrate and astrocyte-released citrate for subsequent metabolism. Slc13a5-knockout mice have been generated; these mice do not have any overt phenotype but are resistant to experimentally induced metabolic syndrome. Recently however, loss-of-function mutations in human SLC13A5 have been found to cause severe epilepsy and encephalopathy early in life. Interestingly, there is no evidence of epilepsy or encephalopathy in Slc13a5-knockout mice, underlining the significant differences in clinical consequences of the loss of function of this transporter between humans and mice. The markedly different biochemical features of human SLC13A5 and mouse Slc13a5 likely contribute to these differences between humans and mice with regard to the metabolic consequences of the transporter deficiency. The exact molecular mechanisms by which the functional deficiency of the citrate transporter causes epilepsy and impairs neuronal development and function remain to be elucidated, but available literature implicate both dysfunction of GABA (γ-aminobutyrate) signaling and hyperfunction of NMDA (N-methyl-d-aspartate) receptor signaling. Plausible synaptic mechanisms linking loss-of-function mutations in SLC13A5 to epilepsy are discussed.
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24
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Willmes DM, Helfand SL, Birkenfeld AL. The longevity transporter mIndy (Slc13a5) as a target for treating hepatic steatosis and insulin resistance. Aging (Albany NY) 2016; 8:208-9. [PMID: 26928109 PMCID: PMC4789574 DOI: 10.18632/aging.100907] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Diana M Willmes
- Section of Metabolic Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany.,Paul Langerhans Institute Dresden (PLID), German Center for Diabetes Research (DZD), Dresden, Germany
| | - Stephen L Helfand
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02912, USA
| | - Andreas L Birkenfeld
- Section of Metabolic Vascular Medicine, Medical Clinic III, Dresden University School of Medicine, Technische Universität Dresden, Dresden, Germany.,Paul Langerhans Institute Dresden (PLID), German Center for Diabetes Research (DZD), Dresden, Germany
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25
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Pesta DH, Perry RJ, Guebre-Egziabher F, Zhang D, Jurczak M, Fischer-Rosinsky A, Daniels MA, Willmes DM, Bhanot S, Bornstein SR, Knauf F, Samuel VT, Shulman GI, Birkenfeld AL. Prevention of diet-induced hepatic steatosis and hepatic insulin resistance by second generation antisense oligonucleotides targeted to the longevity gene mIndy (Slc13a5). Aging (Albany NY) 2016; 7:1086-93. [PMID: 26647160 PMCID: PMC4712334 DOI: 10.18632/aging.100854] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Reducing the expression of the Indy (I'm Not Dead Yet) gene in lower organisms extends life span by mechanisms resembling caloric restriction. Similarly, deletion of the mammalian homolog, mIndy (Slc13a5), encoding for a plasma membrane tricarboxylate transporter, protects from aging- and diet-induced adiposity and insulin resistance in mice. The organ specific contribution to this phenotype is unknown. We examined the impact of selective inducible hepatic knockdown of mIndy on whole body lipid and glucose metabolism using 2′-O-methoxyethyl chimeric anti-sense oligonucleotides (ASOs) in high-fat fed rats. 4-week treatment with 2′-O-methoxyethyl chimeric ASO reduced mIndy mRNA expression by 91% (P<0.001) compared to control ASO. Besides similar body weights between both groups, mIndy-ASO treatment lead to a 74% reduction in fasting plasma insulin concentrations as well as a 35% reduction in plasma triglycerides. Moreover, hepatic triglyceride content was significantly reduced by the knockdown of mIndy, likely mediating a trend to decreased basal rates of endogenous glucose production as well as an increased suppression of hepatic glucose production by 25% during a hyperinsulinemic-euglycemic clamp. Together, these data suggest that inducible liver-selective reduction of mIndy in rats is able to ameliorate hepatic steatosis and insulin resistance, conditions occurring with high calorie diets and during aging.
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Affiliation(s)
- Dominik H Pesta
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.,Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.,Department of Sport Science, Medical Section, University of Innsbruck, Innsbruck, Austria.,Department of Visceral, Transplant, and Thoracic Surgery, D. Swarovski Research Laboratory, Medical University of Innsbruck, Innsbruck, Austria.,Institute for Clinical Diabetology, German Diabetes Center, Leibniz Center for Diabetes Research at Heinrich-Heine University Düsseldorf, German Center for Diabetes Research, Partner Düsseldorf, Düsseldorf, Germany
| | - Rachel J Perry
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.,Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | | | - Dongyan Zhang
- Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA
| | - Michael Jurczak
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA
| | - Antje Fischer-Rosinsky
- Charité - University School of Medicine, Department of Endocrinology, Diabetes and Nutrition, Berlin, Germany
| | - Martin A Daniels
- Charité - University School of Medicine, Department of Endocrinology, Diabetes and Nutrition, Berlin, Germany.,Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), TU Dresden, Germany
| | - Diana M Willmes
- Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), TU Dresden, Germany.,German Center for Diabetes Research (DZD), Dresden, Germany
| | | | - Stefan R Bornstein
- Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), TU Dresden, Germany.,German Center for Diabetes Research (DZD), Dresden, Germany.,Section of Diabetes and Nutritional Sciences, Rayne Institute, King's College London, London, UK
| | - Felix Knauf
- University Clinic Erlangen, Erlangen, Germany
| | - Varman T Samuel
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.,Veterans Affairs Medical Center, West Haven, CT, USA
| | - Gerald I Shulman
- Department of Internal Medicine, Yale University School of Medicine, New Haven, CT, USA.,Cellular and Molecular Physiology, Yale University School of Medicine, New Haven, CT, USA.,Howard Hughes Medical Institute, Yale University School of Medicine, New Haven, CT, USA
| | - Andreas L Birkenfeld
- Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), TU Dresden, Germany.,German Center for Diabetes Research (DZD), Dresden, Germany.,Section of Diabetes and Nutritional Sciences, Rayne Institute, King's College London, London, UK
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26
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Rives ML, Shaw M, Zhu B, Hinke SA, Wickenden AD. State-Dependent Allosteric Inhibition of the Human SLC13A5 Citrate Transporter by Hydroxysuccinic Acids, PF-06649298 and PF-06761281. Mol Pharmacol 2016; 90:766-774. [PMID: 27754898 DOI: 10.1124/mol.116.106575] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 10/13/2016] [Indexed: 01/16/2023] Open
Abstract
In the liver, citrate is a key metabolic intermediate involved in the regulation of glycolysis and lipid synthesis and reduced expression of the hepatic citrate SLC13A5 transporter has been shown to improve metabolic outcomes in various animal models. Although inhibition of hepatic extracellular citrate uptake through SLC13A5 has been suggested as a potential therapeutic approach for Type-2 diabetes and/or fatty liver disease, so far, only a few SLC13A5 inhibitors have been identified. Moreover, their mechanism of action still remains unclear, potentially limiting their utility for in vivo proof-of-concept studies. In this study, we characterized the pharmacology of the recently identified hydroxysuccinic acid SLC13A5 inhibitors, PF-06649298 and PF-06761281, using a combination of 14C-citrate uptake, a membrane potential assay and electrophysiology. In contrast to their previously proposed mechanism of action, our data suggest that both PF-06649298 and PF-06761281 are allosteric, state-dependent SLC13A5 inhibitors, with low-affinity substrate activity in the absence of citrate. As allosteric state-dependent modulators, the inhibitory potency of both compounds is highly dependent on the ambient citrate concentration and our detailed mechanism of action studies therefore, may be of value in interpreting the in vivo effects of these compounds.
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Affiliation(s)
- Marie-Laure Rives
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Morena Shaw
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Bin Zhu
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Simon A Hinke
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
| | - Alan D Wickenden
- Molecular and Cellular Pharmacology, Discovery Sciences, Janssen R&D, LLC., San Diego, California (M.-L.R., M.S., A.D.W.) and Cardiovascular and Metabolism Discovery, Janssen R&D, LLC., Springhouse, Pennsylvania, (B.Z., S.A.H.)
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27
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Brachs S, Winkel AF, Tang H, Birkenfeld AL, Brunner B, Jahn-Hofmann K, Margerie D, Ruetten H, Schmoll D, Spranger J. Inhibition of citrate cotransporter Slc13a5/mINDY by RNAi improves hepatic insulin sensitivity and prevents diet-induced non-alcoholic fatty liver disease in mice. Mol Metab 2016; 5:1072-1082. [PMID: 27818933 PMCID: PMC5081411 DOI: 10.1016/j.molmet.2016.08.004] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 08/02/2016] [Accepted: 08/08/2016] [Indexed: 12/22/2022] Open
Abstract
Objective Non-alcoholic fatty liver disease is a world-wide health concern and risk factor for cardio-metabolic diseases. Citrate uptake modifies intracellular hepatic energy metabolism and is controlled by the conserved sodium-dicarboxylate cotransporter solute carrier family 13 member 5 (SLC13A5, mammalian homolog of INDY: mINDY). In Drosophila melanogaster and Caenorhabditis elegans INDY reduction decreased whole-body lipid accumulation. Genetic deletion of Slc13a5 in mice protected from diet-induced adiposity and insulin resistance. We hypothesized that inducible hepatic mINDY inhibition should prevent the development of fatty liver and hepatic insulin resistance. Methods Adult C57BL/6J mice were fed a Western diet (60% kcal from fat, 21% kcal from carbohydrate) ad libitum. Knockdown of mINDY was induced by weekly injection of a chemically modified, liver-selective siRNA for 8 weeks. Mice were metabolically characterized and the effect of mINDY suppression on glucose tolerance as well as insulin sensitivity was assessed with an ipGTT and a hyperinsulinemic-euglycemic clamp. Hepatic lipid accumulation was determined by biochemical measurements and histochemistry. Results Within the 8 week intervention, hepatic mINDY expression was suppressed by a liver-selective siRNA by over 60%. mINDY knockdown improved hepatic insulin sensitivity (i.e. insulin-induced suppression of endogenous glucose production) of C57BL/6J mice in the hyperinsulinemic-euglycemic clamp. Moreover, the siRNA-mediated mINDY inhibition prevented neutral lipid storage and triglyceride accumulation in the liver, while we found no effect on body weight. Conclusions We show that inducible mINDY inhibition improved hepatic insulin sensitivity and prevented diet-induced non-alcoholic fatty liver disease in adult C57BL6/J mice. These effects did not depend on changes of body weight or body composition. mINDY/Slc13a5 knockdown was induced by liver-selective siRNA in mice. Liver-selective knockdown of mINDY improved hepatic insulin sensitivity. Liver-selective knockdown of mINDY prevented steatosis hepatis.
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Key Words
- 2-DG, 2-Deoxy-d-glucose
- Citrate transport
- EE, energy expenditure
- EGP, endogenous glucose production
- FA, fatty acids
- FLD, fatty liver disease
- GIR, glucose infusion rate
- HE clamp, hyperinsulinemic-euglycemic clamp
- HFD, high-fat diet
- IEX, anion-exchange high-performance liquid chromatography
- INDY, ‘I'm not dead Yet’
- INDY/Slc13a5
- Insulin resistance
- KO, knockout
- Lipid accumulation
- ORO, oil red O
- RER, respiratory exchange ratio
- SCR, non-silencing scrambled control siRNA
- SKM, skeletal muscle
- Steatosis
- T2D, type-2 diabetes
- TCA, tricarboxylic acid
- WAT, white adipose tissue
- WD, western diet
- e, epididymal
- mINDY, Slc13a5/SLC13A5
- p, perirenal
- s, subcutaneous
- siINDY, mINDY-specific siRNA
- siRNA
- solute carrier family 13, member 5
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Affiliation(s)
- Sebastian Brachs
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, 10117, Germany; DZHK (German Center for Cardiovascular Research), Partner Site, Berlin, Germany.
| | - Angelika F Winkel
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main, 65926, Germany.
| | - Hui Tang
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, 10117, Germany; DZHK (German Center for Cardiovascular Research), Partner Site, Berlin, Germany.
| | - Andreas L Birkenfeld
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, 10117, Germany; DZHK (German Center for Cardiovascular Research), Partner Site, Berlin, Germany; Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), a Member of the German Diabetes Center (DZD), Technische Universität, Dresden, 01307, Germany.
| | - Bodo Brunner
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main, 65926, Germany.
| | - Kerstin Jahn-Hofmann
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main, 65926, Germany.
| | - Daniel Margerie
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main, 65926, Germany.
| | - Hartmut Ruetten
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main, 65926, Germany.
| | - Dieter Schmoll
- Sanofi-Aventis Deutschland GmbH, Industriepark Hoechst, Frankfurt am Main, 65926, Germany.
| | - Joachim Spranger
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, 10117, Germany; DZHK (German Center for Cardiovascular Research), Partner Site, Berlin, Germany.
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Schwarz F, Karadeniz Z, Fischer-Rosinsky A, Willmes DM, Spranger J, Birkenfeld AL. Knockdown of Indy/CeNac2 extends Caenorhabditis elegans life span by inducing AMPK/aak-2. Aging (Albany NY) 2016; 7:553-67. [PMID: 26318988 PMCID: PMC4586101 DOI: 10.18632/aging.100791] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Reducing the expression of the Indy (Acronym for ‘I'm Not Dead, Yet’) gene in lower organisms promotes longevity and leads to a phenotype that resembles various aspects of caloric restriction. In C. elegans, the available data on life span extension is controversial. Therefore, the aim of this study was to determine the role of the C. elegans INDY homolog CeNAC2 in life span regulation and to delineate possible molecular mechanisms. siRNA against Indy/CeNAC2 was used to reduce expression of Indy/CeNAC2. Mean life span was assessed in four independent experiments, as well as whole body fat content and AMPK activation. Moreover, the effect of Indy/CeNAC2 knockdown in C. elegans with inactivating variants of AMPK (TG38) was studied. Knockdown of Indy/CeNAC2 increased life span by 22 ± 3% compared to control siRNA treated C. elegans, together with a decrease in whole body fat content by ~50%. Indy/CeNAC2 reduction also increased the activation of the intracellular energy sensor AMPK/aak2. In worms without functional AMPK/aak2, life span was not extended when Indy/CeNAC2 was reduced. Inhibition of glycolysis with deoxyglucose, an intervention known to increase AMPK/aak2 activity and life span, did not promote longevity when Indy/CeNAC2 was knocked down. Together, these data indicate that reducing the expression of Indy/CeNAC2 increases life span in C. elegans, an effect mediated at least in part by AMPK/aak2.
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Affiliation(s)
- Franziska Schwarz
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Zehra Karadeniz
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Antje Fischer-Rosinsky
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Diana M Willmes
- Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), a member of the German Diabetes Center (DZD), Technische Universität Dresden, Germany
| | - Joachim Spranger
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Andreas L Birkenfeld
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany.,Section of Metabolic Vascular Medicine, Medical Clinic III and Paul Langerhans Institute Dresden (PLID), a member of the German Diabetes Center (DZD), Technische Universität Dresden, Germany.,Section of Diabetes and Nutritional Sciences, Rayne Institute, King's College London, UK
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Differential response of the natriuretic peptide system to weight loss and exercise in overweight or obese patients. J Hypertens 2016; 33:1458-64. [PMID: 25882864 DOI: 10.1097/hjh.0000000000000573] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
OBJECTIVE Relative atrial natriuretic peptide (ANP) deficiency has been implicated in the pathogenesis of obesity-associated cardiovascular and metabolic disease. We tested the hypothesis that more than 5% body weight reduction through 6 months hypocaloric dieting alters ANP release at rest and more so during exercise in overweight or obese patients. METHODS Venous mid-regional pro-ANP concentration was assessed at rest and after incremental exhaustive exercise testing before and after weight reduction. We also measured natriuretic peptide receptor A and C mRNA expression in subcutaneous adipose tissue to gauge both ANP responsiveness and clearance mechanisms. RESULTS The average weight reduction of 9.1 ± 3.8 kg was associated with reductions in visceral and subcutaneous abdominal fat mass, liver fat content, insulin resistance, and ambulatory blood pressure. However, mid-regional pro-ANP plasma concentrations were unchanged with weight loss (51 ± 24 vs. 53 ± 24 pmol/l). Exercise elicited similar acute mid-regional pro-ANP increases before and after weight loss. Adipose tissue natriuretic peptide receptor type A mRNA expression remained unchanged, whereas natriuretic peptide receptor type C mRNA decreased with weight loss. CONCLUSIONS We conclude that physical exercise acutely increases ANP release in obese patients, whereas modest diet-induced weight loss primarily affects ANP clearance mechanisms. Interventions combining weight loss and regular physical exercise may be particularly efficacious in reversing obesity-associated relative natriuretic peptide deficiency.
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Li Z, Erion DM, Maurer TS. Model-Based Assessment of Plasma Citrate Flux Into the Liver: Implications for NaCT as a Therapeutic Target. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2016; 5:132-9. [PMID: 27069776 PMCID: PMC4809623 DOI: 10.1002/psp4.12062] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 01/25/2016] [Indexed: 12/26/2022]
Abstract
Cytoplasmic citrate serves as an important regulator of gluconeogenesis and carbon source for de novo lipogenesis in the liver. For this reason, the sodium-coupled citrate transporter (NaCT), a plasma membrane transporter that governs hepatic influx of plasma citrate in human, is being explored as a potential therapeutic target for metabolic disorders. As cytoplasmic citrate also originates from intracellular mitochondria, the relative contribution of these two pathways represents critical information necessary to underwrite confidence in this target. In this work, hepatic influx of plasma citrate was quantified via pharmacokinetic modeling of published clinical data. The influx was then compared to independent literature estimates of intracellular citrate flux in human liver. The results indicate that, under normal conditions, <10% of hepatic citrate originates from plasma. Similar estimates were determined experimentally in mice and rats. This suggests that NaCT inhibition will have a limited impact on hepatic citrate concentrations across species.
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Affiliation(s)
- Z Li
- Systems Modeling and Simulation Pharmacokinetics, Pharmacodynamics, and Metabolism, Pfizer Global Research and Development Cambridge Massachusetts USA
| | - D M Erion
- Cardiovascular, Metabolic & Endocrine Disease Research Unit Cambridge Massachusetts USA
| | - T S Maurer
- Systems Modeling and Simulation Pharmacokinetics, Pharmacodynamics, and Metabolism, Pfizer Global Research and Development Cambridge Massachusetts USA
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Neuschäfer-Rube F, Schraplau A, Schewe B, Lieske S, Krützfeldt JM, Ringel S, Henkel J, Birkenfeld AL, Püschel GP. Arylhydrocarbon receptor-dependent mIndy (Slc13a5) induction as possible contributor to benzo[a]pyrene-induced lipid accumulation in hepatocytes. Toxicology 2015; 337:1-9. [PMID: 26303333 DOI: 10.1016/j.tox.2015.08.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Revised: 08/14/2015] [Accepted: 08/17/2015] [Indexed: 01/07/2023]
Abstract
Non-alcoholic fatty liver disease is a growing problem in industrialized and developing countries. Hepatic lipid accumulation is the result of an imbalance between fatty acid uptake, fatty acid de novo synthesis, β-oxidation and secretion of triglyceride-rich lipoproteins from the hepatocyte. A central regulator of hepatic lipid metabolism is cytosolic citrate that can either be derived from the mitochondrium or be taken up from the blood via the plasma membrane sodium citrate transporter NaCT, the product of the mammalian INDY gene (SLC13A5). mINDY ablation protects against diet-induced steatosis whereas mINDY expression is increased in patients with hepatic steatosis. Diet-induced hepatic steatosis is also enhanced by activation of the arylhyrocarbon receptor (AhR) both in humans and animal models. Therefore, the hypothesis was tested whether the mINDY gene might be a target of the AhR. In accordance with such a hypothesis, the AhR activator benzo[a]pyrene induced the mINDY expression in primary cultures of rat hepatocytes in an AhR-dependent manner. This induction resulted in an increased citrate uptake and citrate incorporation into lipids which probably was further enhanced by the benzo[a]pyrene-dependent induction of key enzymes of fatty acid synthesis. A potential AhR binding site was identified in the mINDY promoter that appears to be conserved in the human promoter. Elimination or mutation of this site largely abolished the activation of the mINDY promoter by benzo[a]pyrene. This study thus identified the mINDY as an AhR target gene. AhR-dependent induction of the mINDY gene might contribute to the development of hepatic steatosis.
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Affiliation(s)
- Frank Neuschäfer-Rube
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Anne Schraplau
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Bettina Schewe
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Stefanie Lieske
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany; Section of Metabolic Vascular Medicine and Paul Langerhans Institute Dresden (PLID), Medical Clinic III, University Clinic Dresden, TU Dresden, 01307, Germany
| | - Julia-Mignon Krützfeldt
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Sebastian Ringel
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Janin Henkel
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany
| | - Andreas L Birkenfeld
- Section of Metabolic Vascular Medicine and Paul Langerhans Institute Dresden (PLID), Medical Clinic III, University Clinic Dresden, TU Dresden, 01307, Germany; Division of Diabetes & Nutritional Sciences, Faculty of Life Sciences & Medicine, King's College London, London SE1 8WA, UK
| | - Gerhard P Püschel
- University of Potsdam, Institute of Nutritional Science, Department of Nutritional Biochemistry, Arthur-Scheunert-Allee 114-116, D-14558 Nuthetal, Germany.
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Rogers RP, Rogina B. The role of INDY in metabolism, health and longevity. Front Genet 2015; 6:204. [PMID: 26106407 PMCID: PMC4460575 DOI: 10.3389/fgene.2015.00204] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 05/25/2015] [Indexed: 11/24/2022] Open
Abstract
Indy (I’m Not Dead Yet) encodes the fly homolog of a mammalian SLC13A5 plasma membrane transporter. INDY is expressed in metabolically active tissues functioning as a transporter of Krebs cycle intermediates with the highest affinity for citrate. Decreased expression of the Indy gene extends longevity in Drosophila and C. elegans. Reduction of INDY or its respective homologs in C. elegans and mice induces metabolic and physiological changes similar to those observed in calorie restriction. It is thought that these physiological changes are due to altered levels of cytoplasmic citrate, which directly impacts Krebs cycle energy production as a result of shifts in substrate availability. Citrate cleavage is a key event during lipid and glucose metabolism; thus, reduction of citrate due to Indy reduction alters these processes. With regards to mammals, mice with reduced Indy (mIndy–/–) also exhibit changes in glucose metabolism, mitochondrial biogenesis and are protected from the negative effects of a high calorie diet. Together, these data support a role for Indy as a metabolic regulator, which suggests INDY as a therapeutic target for treatment of diet and age-related disorders such as Type II Diabetes and obesity.
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Affiliation(s)
- Ryan P Rogers
- Department of Sciences, Wentworth Institute of Technology , Boston, MA, USA
| | - Blanka Rogina
- Department of Genetics and Genome Sciences, Institute for Systems Genomics, School of Medicine, University of Connecticut Health Center , Farmington, CT, USA
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Schlueter N, de Sterke A, Willmes DM, Spranger J, Jordan J, Birkenfeld AL. Metabolic actions of natriuretic peptides and therapeutic potential in the metabolic syndrome. Pharmacol Ther 2014; 144:12-27. [PMID: 24780848 DOI: 10.1016/j.pharmthera.2014.04.007] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2014] [Accepted: 04/14/2014] [Indexed: 12/26/2022]
Abstract
Natriuretic peptides (NPs) are a group of peptide-hormones mainly secreted from the heart, signaling via c-GMP coupled receptors. NP are well known for their renal and cardiovascular actions, reducing arterial blood pressure as well as sodium reabsorption. Novel physiological functions have been discovered in recent years, including activation of lipolysis, lipid oxidation, and mitochondrial respiration. Together, these responses promote white adipose tissue browning, increase muscular oxidative capacity, particularly during physical exercise, and protect against diet-induced obesity and insulin resistance. Exaggerated NP release is a common finding in congestive heart failure. In contrast, NP deficiency is observed in obesity and in type-2 diabetes, pointing to an involvement of NP in the pathophysiology of metabolic disease. Based upon these findings, the NP system holds the potential to be amenable to therapeutical intervention against pandemic diseases such as obesity, insulin resistance, and arterial hypertension. Various therapeutic approaches are currently under development. This paper reviews the current knowledge on the metabolic effects of the NP system and discusses potential therapeutic applications.
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Affiliation(s)
- Nina Schlueter
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité, University School of Medicine, Berlin, Germany
| | - Anita de Sterke
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité, University School of Medicine, Berlin, Germany
| | - Diana M Willmes
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité, University School of Medicine, Berlin, Germany
| | - Joachim Spranger
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité, University School of Medicine, Berlin, Germany
| | - Jens Jordan
- Institute of Clinical Pharmacology, Hannover Medical School, Hannover, Germany
| | - Andreas L Birkenfeld
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité, University School of Medicine, Berlin, Germany.
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Willmes DM, Birkenfeld AL. The Role of INDY in Metabolic Regulation. Comput Struct Biotechnol J 2013; 6:e201303020. [PMID: 24688728 PMCID: PMC3962103 DOI: 10.5936/csbj.201303020] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Revised: 12/02/2013] [Accepted: 12/02/2013] [Indexed: 01/20/2023] Open
Abstract
Reduced expression of the Indy (I'm Not Dead Yet) gene in D. melanogaster and C. elegans extends longevity. Indy and its mammalian homolog mINDY (Slc13a5, NaCT) are transporters of TCA cycle intermediates, mainly handling the uptake of citrate via the plasma membrane into the cytosol. Deletion of mINDY in mice leads to significant metabolic changes akin to caloric restriction, likely caused by reducing the effects of mINDY-imported citrate on fatty acid and cholesterol synthesis, glucose metabolism and ß-oxidation. This review will provide an overview on different mammalian SLC1 3 family members with a focus on mINDY (SLCl3A5) in glucose and energy metabolism and will highlight the role of mINDY as a putative therapeutic target for the treatment of obesity, non-alcoholic fatty liver disease and type 2 diabetes.
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Affiliation(s)
- Diana M Willmes
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
| | - Andreas L Birkenfeld
- Department of Endocrinology, Diabetes and Nutrition, Center for Cardiovascular Research, Charité - University School of Medicine, Berlin, Germany
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