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] [What about the content of this article? (0)] [Affiliation(s)] [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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Mondkar SA, Khadilkar V, Kasegaonkar P, Khadilkar A. SOFT syndrome with kohlschutter-Tonz syndrome. J Postgrad Med 2024; 70:56-59. [PMID: 37706418 PMCID: PMC10947733 DOI: 10.4103/jpgm.jpgm_1001_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2022] [Revised: 05/23/2023] [Accepted: 07/24/2023] [Indexed: 09/15/2023] Open
Abstract
We report a 2.2 year-old-boy, born of consanguineous marriage, referred for short stature, with history of neonatal death and skeletal deformities in his older sibling. Rhizo-mesomelic dwarfism was detected antenatally. Within 24 hours of birth, he developed multiple seizures. Examination revealed severe short stature, dolichocephaly, broad forehead, deep set eyes, low set ears, bulbous nose, small, irregular teeth, pointed chin, and triangular facies. He had rhizomelic shortening, stubby fingers, pes planus, and scanty hair. Neurological evaluation revealed ataxia, hypotonia, and global developmental delay. Skeletal survey radiograph revealed shallow acetabuli, short femurs and humerus, short, broad metacarpals and short cone-shaped phalanges with cupping of phalangeal bases. Clinical exome analysis revealed homozygous mutations involving the POC1A gene and the SLC13A5 gene responsible for SOFT syndrome and Kohlschutter-Tonz syndrome respectively, which were inherited from the parents. Both these syndromes are extremely rare, and their co-occurrence is being reported for the first time.
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Affiliation(s)
- SA Mondkar
- Growth and Pediatric Endocrinology Unit, Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune, Maharashtra, India
| | - V Khadilkar
- Growth and Pediatric Endocrinology Unit, Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune, Maharashtra, India
| | - P Kasegaonkar
- Department of Neurology, CNS Hospital, Solapur, Maharashtra, India
| | - A Khadilkar
- Growth and Pediatric Endocrinology Unit, Hirabai Cowasji Jehangir Medical Research Institute, Jehangir Hospital, Pune, Maharashtra, India
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3
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Gill D, Zagkos L, Gill R, Benzing T, Jordan J, Birkenfeld AL, Burgess S, Zahn G. The citrate transporter SLC13A5 as a therapeutic target for kidney disease: evidence from Mendelian randomization to inform drug development. BMC Med 2023; 21:504. [PMID: 38110950 PMCID: PMC10729503 DOI: 10.1186/s12916-023-03227-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2023] [Accepted: 12/12/2023] [Indexed: 12/20/2023] Open
Abstract
BACKGROUND Solute carrier family 13 member 5 (SLC13A5) is a Na+-coupled citrate co-transporter that mediates entry of extracellular citrate into the cytosol. SLC13A5 inhibition has been proposed as a target for reducing progression of kidney disease. The aim of this study was to leverage the Mendelian randomization paradigm to gain insight into the effects of SLC13A5 inhibition in humans, towards prioritizing and informing clinical development efforts. METHODS The primary Mendelian randomization analyses investigated the effect of SLC13A5 inhibition on measures of kidney function, including creatinine and cystatin C-based measures of estimated glomerular filtration rate (creatinine-eGFR and cystatin C-eGFR), blood urea nitrogen (BUN), urine albumin-creatinine ratio (uACR), and risk of chronic kidney disease and microalbuminuria. Secondary analyses included a paired plasma and urine metabolome-wide association study, investigation of secondary traits related to SLC13A5 biology, a phenome-wide association study (PheWAS), and a proteome-wide association study. All analyses were compared to the effect of genetically predicted plasma citrate levels using variants selected from across the genome, and statistical sensitivity analyses robust to the inclusion of pleiotropic variants were also performed. Data were obtained from large-scale genetic consortia and biobanks, with sample sizes ranging from 5023 to 1,320,016 individuals. RESULTS We found evidence of associations between genetically proxied SLC13A5 inhibition and higher creatinine-eGFR (p = 0.002), cystatin C-eGFR (p = 0.005), and lower BUN (p = 3 × 10-4). Statistical sensitivity analyses robust to the inclusion of pleiotropic variants suggested that these effects may be a consequence of higher plasma citrate levels. There was no strong evidence of associations of genetically proxied SLC13A5 inhibition with uACR or risk of CKD or microalbuminuria. Secondary analyses identified evidence of associations with higher plasma calcium levels (p = 6 × 10-13) and lower fasting glucose (p = 0.02). PheWAS did not identify any safety concerns. CONCLUSIONS This Mendelian randomization analysis provides human-centric insight to guide clinical development of an SLC13A5 inhibitor. We identify plasma calcium and citrate as biologically plausible biomarkers of target engagement, and plasma citrate as a potential biomarker of mechanism of action. Our human genetic evidence corroborates evidence from various animal models to support effects of SLC13A5 inhibition on improving kidney function.
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Affiliation(s)
- Dipender Gill
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK.
- Primula Group Ltd, London, UK.
| | - Loukas Zagkos
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK
| | | | - Thomas Benzing
- Department II of Internal Medicine and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Faculty of Medicine and University Hospital Cologne, Cologne, Germany
- Cologne Excellence Cluster On Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of Cologne, Cologne, Germany
| | - Jens Jordan
- Institute of Aerospace Medicine, German Aerospace Center (DLR), Cologne, Germany
- Medical Faculty, University of Cologne, Cologne, Germany
| | - Andreas L Birkenfeld
- Department of Diabetology Endocrinology and Nephrology, Internal Medicine IV, University Hospital Tübingen, Eberhard Karls University Tübingen, Tübingen, Germany
- Division of Translational Diabetology, Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich, Eberhard Karls University Tübingen, Tübingen, Germany
- Department of Diabetes, School of Life Course Science and Medicine, King's College London, London, UK
| | - Stephen Burgess
- Medical Research Council Biostatistics Unit at the University of Cambridge, Cambridge, UK
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Zahn G, Baukmann HA, Wu J, Jordan J, Birkenfeld AL, Dirckx N, Schmidt MF. Targeting Longevity Gene SLC13A5: A Novel Approach to Prevent Age-Related Bone Fragility and Osteoporosis. Metabolites 2023; 13:1186. [PMID: 38132868 PMCID: PMC10744747 DOI: 10.3390/metabo13121186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 11/24/2023] [Accepted: 12/01/2023] [Indexed: 12/23/2023] Open
Abstract
Reduced expression of the plasma membrane citrate transporter SLC13A5, also known as INDY, has been linked to increased longevity and mitigated age-related cardiovascular and metabolic diseases. Citrate, a vital component of the tricarboxylic acid cycle, constitutes 1-5% of bone weight, binding to mineral apatite surfaces. Our previous research highlighted osteoblasts' specialized metabolic pathway facilitated by SLC13A5 regulating citrate uptake, production, and deposition within bones. Disrupting this pathway impairs bone mineralization in young mice. New Mendelian randomization analysis using UK Biobank data indicated that SNPs linked to reduced SLC13A5 function lowered osteoporosis risk. Comparative studies of young (10 weeks) and middle-aged (52 weeks) osteocalcin-cre-driven osteoblast-specific Slc13a5 knockout mice (Slc13a5cKO) showed a sexual dimorphism: while middle-aged females exhibited improved elasticity, middle-aged males demonstrated enhanced bone strength due to reduced SLC13A5 function. These findings suggest reduced SLC13A5 function could attenuate age-related bone fragility, advocating for SLC13A5 inhibition as a potential osteoporosis treatment.
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Affiliation(s)
- Grit Zahn
- Eternygen GmbH, Westhafenstrasse 1, 13353 Berlin, Germany
| | | | - Jasmine Wu
- Department of Orthopaedics, School of Medicine, University of Maryland-Baltimore, Baltimore, MD 21201, USA
| | - Jens Jordan
- German Aerospace Center (DLR), Institute of Aerospace Medicine, 51147 Cologne, Germany;
| | - Andreas L. Birkenfeld
- Department of Diabetology Endocrinology and Nephrology, Internal Medicine IV, University Hospital Tübingen, Eberhard Karls University Tübingen, 72074 Tübingen, Germany
- German Center for Diabetes Research (DZD), Institute of Diabetes Research and Metabolic Diseases (IDM) of the Helmholtz Center Munich, Eberhard Karls University Tübingen, 72074 Tübingen, Germany
- Department of Diabetes, Life Sciences and Medicine, Cardiovascular Medicine and Sciences, Kings College London, London WC2R 2LS, UK
| | - Naomi Dirckx
- Department of Orthopaedics, School of Medicine, University of Maryland-Baltimore, Baltimore, MD 21201, USA
| | - Marco F. Schmidt
- biotx.ai GmbH, Am Mühlenberg 11, 14476 Potsdam, Germany (M.F.S.)
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Kopel J, Clothier J. Lessons From an MD PhD - From SLC13A5 to Neurology. J Community Hosp Intern Med Perspect 2023; 13:4-7. [PMID: 37868677 PMCID: PMC10589030 DOI: 10.55729/2000-9666.1211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/14/2023] [Accepted: 04/21/2023] [Indexed: 10/24/2023] Open
Abstract
The journey towards becoming a physician scientist is a long, arduous, and uncertain journey. Few medical students pursue a career as a physician scientist. Even those that do, the path towards maintaining a robust research career and clinical training can be difficult given the personal and social pressures to focus solely on research or clinical work. Despite the long history of science and medicine, there is question concerning the role that physician scientist in modern medicine. As a recent physician scientist graduate, physician scientists are greatly needed in the medical profession. The ability to overlap science, medicine, and the humanities together is an essential part of the producing a well-rounded and effective physician for a rapidly changing profession and world. Through my journey as a physician scientist in training, the lessons I've learned through my training in both the basic science and clinical portions can be helpful for medical students traversing both sides of the divide.
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Affiliation(s)
- Jonathan Kopel
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX, USA
| | - Jeffrey Clothier
- Department of Psychiatry, University of Arkansas for Medical Sciences, Little Rock, AR, USA
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Spelbrink EM, Brown TL, Brimble E, Blanco KA, Nye KL, Porter BE. Characterizing a rare neurogenetic disease, SLC13A5 citrate transporter disorder, utilizing clinical data in a cloud-based medical record collection system. Front Genet 2023; 14:1109547. [PMID: 37025451 PMCID: PMC10072280 DOI: 10.3389/fgene.2023.1109547] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 02/22/2023] [Indexed: 04/08/2023] Open
Abstract
Introduction: SLC13A5 citrate transporter disorder is a rare autosomal recessive genetic disease that has a constellation of neurologic symptoms. To better characterize the neurologic and clinical laboratory phenotype, we utilized patient medical records collected by Ciitizen, an Invitae company, with support from the TESS Research Foundation. Methods: Medical records for 15 patients with a suspected genetic and clinical diagnosis of SLC13A5 citrate transporter disorder were collected by Ciitizen, an Invitae company. Genotype, clinical phenotypes, and laboratory data were extracted and analyzed. Results: The 15 patients reported all had epilepsy and global developmental delay. Patients continued to attain motor milestones, though much later than their typically developing peers. Clinical diagnoses support abnormalities in communication, and low or mixed tone with several movement disorders, including, ataxia and dystonia. Serum citrate was elevated in the 3 patients in whom it was measured; other routine laboratory studies assessing renal, liver and blood function had normal values or no consistent abnormalities. Many electroencephalograms (EEGs) were performed (1 to 35 per patient), and most but not all were abnormal, with slowing and/or epileptiform activity. Fourteen of the patients had one or more brain magnetic resonance imaging (MRI) reports: 7 patients had at least one normal brain MRI, but not with any consistent findings except white matter signal changes. Discussion: These results show that in addition to the epilepsy phenotype, SLC13A5 citrate transporter disorder impacts global development, with marked abnormalities in motor abilities, tone, coordination, and communication skills. Further, utilizing cloud-based medical records allows industry, academic, and patient advocacy group collaboration to provide preliminary characterization of a rare genetic disorder. Additional characterization of the neurologic phenotype will be critical to future study and developing treatment for this and related rare genetic disorders.
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Affiliation(s)
- Emily M. Spelbrink
- Stanford University School of Medicine, Department of Neurology and Neurological Sciences, Palo Alto, CA, United States
| | - Tanya L. Brown
- Treatments for Epilepsy and Symptoms of SLC13A5 Foundation, TESS Research Foundation, Menlo Park, CA, United States
| | | | - Kirsten A. Blanco
- Invitae, San Francisco, CA, United States
- Department of Genetics, Stanford University, Stanford, CA, United States
| | - Kimberly L. Nye
- Treatments for Epilepsy and Symptoms of SLC13A5 Foundation, TESS Research Foundation, Menlo Park, CA, United States
| | - Brenda E. Porter
- Stanford University School of Medicine, Department of Neurology and Neurological Sciences, Palo Alto, CA, United States
- *Correspondence: Brenda E. Porter,
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Goodspeed K, Liu JS, Nye KL, Prasad S, Sadhu C, Tavakkoli F, Bilder DA, Minassian BA, Bailey RM. SLC13A5 Deficiency Disorder: From Genetics to Gene Therapy. Genes (Basel) 2022; 13:genes13091655. [PMID: 36140822 PMCID: PMC9498415 DOI: 10.3390/genes13091655] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Revised: 09/05/2022] [Accepted: 09/07/2022] [Indexed: 11/16/2022] Open
Abstract
Epileptic encephalopathies may arise from single gene variants. In recent years, next-generation sequencing technologies have enabled an explosion of gene identification in monogenic epilepsies. One such example is the epileptic encephalopathy SLC13A5 deficiency disorder, which is caused by loss of function pathogenic variants to the gene SLC13A5 that results in deficiency of the sodium/citrate cotransporter. Patients typically experience seizure onset within the first week of life and have developmental delay and intellectual disability. Current antiseizure medications may reduce seizure frequency, yet more targeted treatments are needed to address the epileptic and non-epileptic features of SLC13A5 deficiency disorder. Gene therapy may offer hope to these patients and better clinical outcomes than current available treatments. Here, we discuss SLC13A5 genetics, natural history, available treatments, potential outcomes and assessments, and considerations for translational medical research for an AAV9-based gene replacement therapy.
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Affiliation(s)
- Kimberly Goodspeed
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Judy S. Liu
- Warren Alpert School of Medicine, Brown University, Providence, RI 02903, USA
| | | | - Suyash Prasad
- Department of Research & Development, Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Chanchal Sadhu
- Department of Research & Development, Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Fatemeh Tavakkoli
- Department of Research & Development, Taysha Gene Therapies, Dallas, TX 75247, USA
| | - Deborah A. Bilder
- Division of Child & Adolescent Psychiatry, Department of Psychiatry, University of Utah, Salt Lake City, UT 84108, USA
| | - Berge A. Minassian
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX 75390, USA
| | - Rachel M. Bailey
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX 75390, USA
- Center for Alzheimer’s and Neurodegenerative Diseases, University of Texas Southwestern, Dallas, TX 75390, USA
- Correspondence: ; Tel.: +1-214-648-8510
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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. Front 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Milosavljevic S, Glinton KE, Li X, Medeiros C, Gillespie P, Seavitt JR, Graham BH, Elsea SH. Untargeted Metabolomics of Slc13a5 Deficiency Reveal Critical Liver-Brain Axis for Lipid Homeostasis. Metabolites 2022; 12:metabo12040351. [PMID: 35448538 PMCID: PMC9032242 DOI: 10.3390/metabo12040351] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/29/2022] [Accepted: 04/03/2022] [Indexed: 01/17/2023] Open
Abstract
Though biallelic variants in SLC13A5 are known to cause severe encephalopathy, the mechanism of this disease is poorly understood. SLC13A5 protein deficiency reduces citrate transport into the cell. Downstream abnormalities in fatty acid synthesis and energy generation have been described, though biochemical signs of these perturbations are inconsistent across SLC13A5 deficiency patients. To investigate SLC13A5-related disorders, we performed untargeted metabolic analyses on the liver, brain, and serum from a Slc13a5-deficient mouse model. Metabolomic data were analyzed using the connect-the-dots (CTD) methodology and were compared to plasma and CSF metabolomics from SLC13A5-deficient patients. Mice homozygous for the Slc13a5tm1b/tm1b null allele had perturbations in fatty acids, bile acids, and energy metabolites in all tissues examined. Further analyses demonstrated that for several of these molecules, the ratio of their relative tissue concentrations differed widely in the knockout mouse, suggesting that deficiency of Slc13a5 impacts the biosynthesis and flux of metabolites between tissues. Similar findings were observed in patient biofluids, indicating altered transport and/or flux of molecules involved in energy, fatty acid, nucleotide, and bile acid metabolism. Deficiency of SLC13A5 likely causes a broader state of metabolic dysregulation than previously recognized, particularly regarding lipid synthesis, storage, and metabolism, supporting SLC13A5 deficiency as a lipid disorder.
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Affiliation(s)
- Sofia Milosavljevic
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; (S.M.); (K.E.G.); (X.L.); (J.R.S.)
- Harvard Medical School, Boston, MA 02215, USA
| | - Kevin E. Glinton
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; (S.M.); (K.E.G.); (X.L.); (J.R.S.)
| | - Xiqi Li
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; (S.M.); (K.E.G.); (X.L.); (J.R.S.)
| | - Cláudia Medeiros
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (C.M.); (P.G.); (B.H.G.)
| | - Patrick Gillespie
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (C.M.); (P.G.); (B.H.G.)
| | - John R. Seavitt
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; (S.M.); (K.E.G.); (X.L.); (J.R.S.)
| | - Brett H. Graham
- Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA; (C.M.); (P.G.); (B.H.G.)
| | - Sarah H. Elsea
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; (S.M.); (K.E.G.); (X.L.); (J.R.S.)
- Correspondence: ; Tel.: +1-713-798-5484
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Rigby MJ, Orefice NS, Lawton AJ, Ma M, Shapiro SL, Yi SY, Dieterich IA, Frelka A, Miles HN, Pearce RA, Yu JPJ, Li L, Denu JM, Puglielli L. SLC13A5/sodium-citrate co-transporter overexpression causes disrupted white matter integrity and an autistic-like phenotype. Brain Commun 2022; 4:fcac002. [PMID: 35146426 PMCID: PMC8823335 DOI: 10.1093/braincomms/fcac002] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/19/2021] [Accepted: 01/03/2022] [Indexed: 09/11/2023] Open
Abstract
Endoplasmic reticulum-based N ɛ-lysine acetylation serves as an important protein quality control system for the secretory pathway. Dysfunctional endoplasmic reticulum-based acetylation, as caused by overexpression of the acetyl coenzyme A transporter AT-1 in the mouse, results in altered glycoprotein flux through the secretory pathway and an autistic-like phenotype. AT-1 works in concert with SLC25A1, the citrate/malate antiporter in the mitochondria, SLC13A5, the plasma membrane sodium/citrate symporter and ATP citrate lyase, the cytosolic enzyme that converts citrate into acetyl coenzyme A. Here, we report that mice with neuron-specific overexpression of SLC13A5 exhibit autistic-like behaviours with a jumping stereotypy. The mice displayed disrupted white matter integrity and altered synaptic structure and function. Analysis of both the proteome and acetyl-proteome revealed unique adaptations in the hippocampus and cortex, highlighting a metabolic response that likely plays an important role in the SLC13A5 neuron transgenic phenotype. Overall, our results support a mechanistic link between aberrant intracellular citrate/acetyl coenzyme A flux and the development of an autistic-like phenotype.
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Affiliation(s)
- Michael J. Rigby
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Nicola Salvatore Orefice
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Alexis J. Lawton
- Department of Biomolecular Chemistry and the Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Min Ma
- School of Pharmacy and Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Samantha L. Shapiro
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Sue Y. Yi
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Inca A. Dieterich
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Alyssa Frelka
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Hannah N. Miles
- School of Pharmacy and Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - Robert A. Pearce
- Department of Anesthesiology, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - John Paul J. Yu
- Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705, USA
| | - Lingjun Li
- School of Pharmacy and Department of Chemistry, University of Wisconsin-Madison, Madison, WI 53705, USA
| | - John M. Denu
- Department of Biomolecular Chemistry and the Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI 53705, USA
- Geriatric Research Education Clinical Center, Veterans Affairs Medical Center, Madison, WI 53705, USA
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11
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Simmer JP, Hu JCC, Hu Y, Zhang S, Liang T, Wang SK, Kim JW, Yamakoshi Y, Chun YH, Bartlett JD, Smith CE. A genetic model for the secretory stage of dental enamel formation. J Struct Biol 2021; 213:107805. [PMID: 34715329 PMCID: PMC8665125 DOI: 10.1016/j.jsb.2021.107805] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/18/2021] [Accepted: 10/20/2021] [Indexed: 01/13/2023]
Abstract
The revolution in genetics has rapidly increased our knowledge of human and mouse genes that are critical for the formation of dental enamel and helps us understand how enamel evolved. In this graphical review we focus on the roles of 41 genes that are essential for the secretory stage of amelogenesis when characteristic enamel mineral ribbons initiate on dentin and elongate to expand the enamel layer to the future surface of the tooth. Based upon ultrastructural analyses of genetically modified mice, we propose a molecular model explaining how a cell attachment apparatus including collagen 17, α6ß4 and αvß6 integrins, laminin 332, and secreted enamel proteins could attach to individual enamel mineral ribbons and mold their cross-sectional dimensions as they simultaneously elongate and orient them in the direction of the retrograde movement of the ameloblast membrane.
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Affiliation(s)
- James P Simmer
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA.
| | - Jan C-C Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA.
| | - Yuanyuan Hu
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA.
| | - Shelly Zhang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA.
| | - Tian Liang
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA.
| | - Shih-Kai Wang
- Department of Dentistry, National Taiwan University School of Dentistry, No. 1, Changde St., Zhongzheng Dist., Taipei City 100, Taiwan; Department of Pediatric Dentistry, National Taiwan University Children's Hospital, No. 8, Zhongshan S. Rd., Zhongzheng Dist., Taipei City 100, Taiwan.
| | - Jung-Wook Kim
- Department of Molecular Genetics, School of Dentistry & Dental Research Institute, Seoul National University, Seoul, Korea; Department of Pediatric Dentistry, School of Dentistry & Dental Research Institute, Seoul National University, Seoul, Korea.
| | - Yasuo Yamakoshi
- Department of Biochemistry and Molecular Biology, School of Dental Medicine, Tsurumi University, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan.
| | - Yong-Hee Chun
- Department of Periodontics, School of Dentistry, University of Texas Health Science Center at San Antonio, San Antonio, TX, USA.
| | - John D Bartlett
- Division of Biosciences, Ohio State University College of Dentistry, Columbus, OH, USA.
| | - Charles E Smith
- Department of Biologic and Materials Sciences, University of Michigan School of Dentistry, 1011 North University, Ann Arbor, MI 48108, USA; Department of Anatomy & Cell Biology, Faculty of Medicine & Health Sciences, McGill University, Montreal, Quebec H3A 0C7, Canada.
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12
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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13
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Brown TL, Nye KL, Porter BE. Growth and Overall Health of Patients with SLC13A5 Citrate Transporter Disorder. Metabolites 2021; 11:metabo11110746. [PMID: 34822404 PMCID: PMC8625967 DOI: 10.3390/metabo11110746] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Revised: 10/22/2021] [Accepted: 10/27/2021] [Indexed: 11/16/2022] Open
Abstract
We were interested in elucidating the non-neurologic health of patients with autosomal recessive SLC13A5 Citrate Transporter (NaCT) Disorder. Multiple variants have been reported that cause a loss of transporter activity, resulting in significant neurologic impairment, including seizures, as well as motor and cognitive dysfunction. Additionally, most patients lack tooth enamel (amelogenesis imperfecta). However, patients have not had their overall health and growth described in detail. Here we characterized the non-neurologic health of 15 patients with medical records uploaded to Ciitizen, a cloud-based patient medical records portal. Ciitizen used a query method for data extraction. Overall, the patients’ records suggested a moderate number of gastrointestinal issues related to feeding, reflux, vomiting and weight gain and a diverse number of respiratory complaints. Other organ systems had single or no abnormal diagnoses, including liver, renal and cardiac. Growth parameters were mostly in the normal range during early life, with a trend toward slower growth in the few adolescent patients with data available. The gastrointestinal and pulmonary issues may at least partially be explained by the severity of the neurologic disorder. More data are needed to clarify if growth is impacted during adolescence and if adult patients develop or are protected from non-neurologic disorders.
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Affiliation(s)
- Tanya L. Brown
- Treatments for Epilepsy and Symptoms of SLC13A5 Foundation, TESS Research Foundation, Menlo Park, CA 94026, USA;
- Correspondence:
| | - Kimberly L. Nye
- Treatments for Epilepsy and Symptoms of SLC13A5 Foundation, TESS Research Foundation, Menlo Park, CA 94026, USA;
| | - Brenda E. Porter
- Department of Neurology and Neurological Sciences, Stanford University, Palo Alto, CA 94070, USA;
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14
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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15
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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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16
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Jaramillo-Martinez V, Sivaprakasam S, Ganapathy V, Urbatsch IL. Drosophila INDY and Mammalian INDY: Major Differences in Transport Mechanism and Structural Features despite Mostly Similar Biological Functions. Metabolites 2021; 11:metabo11100669. [PMID: 34677384 PMCID: PMC8537002 DOI: 10.3390/metabo11100669] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Accepted: 09/27/2021] [Indexed: 12/12/2022] Open
Abstract
INDY (I’m Not Dead Yet) is a plasma membrane transporter for citrate, first identified in Drosophila. Partial deficiency of INDY extends lifespan in this organism in a manner similar to that of caloric restriction. The mammalian counterpart (NaCT/SLC13A5) also transports citrate. In mice, it is the total, not partial, absence of the transporter that leads to a metabolic phenotype similar to that caloric restriction; however, there is evidence for subtle neurological dysfunction. Loss-of-function mutations in SLC13A5 (solute carrier gene family 13, member A5) occur in humans, causing a recessive disease, with severe clinical symptoms manifested by neonatal seizures and marked disruption in neurological development. Though both Drosophila INDY and mammalian INDY transport citrate, the translocation mechanism differs, the former being a dicarboxylate exchanger for the influx of citrate2− in exchange for other dicarboxylates, and the latter being a Na+-coupled uniporter for citrate2−. Their structures also differ as evident from only ~35% identity in amino acid sequence and from theoretically modeled 3D structures. The varied biological consequences of INDY deficiency across species, with the beneficial effects predominating in lower organisms and detrimental effects overwhelming in higher organisms, are probably reflective of species-specific differences in tissue expression and also in relative contribution of extracellular citrate to metabolic pathways in different tissues
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Affiliation(s)
- Valeria Jaramillo-Martinez
- Department of Pharmacology and Neuroscience, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA;
| | - Sathish Sivaprakasam
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.S.); (V.G.)
| | - Vadivel Ganapathy
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.S.); (V.G.)
| | - Ina L. Urbatsch
- Department of Cell Biology and Biochemistry, Texas Tech University Health Sciences Center, Lubbock, TX 79430, USA; (S.S.); (V.G.)
- Correspondence:
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17
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Kumar A, Cordes T, Thalacker-Mercer AE, Pajor AM, Murphy AN, Metallo CM. NaCT/ SLC13A5 facilitates citrate import and metabolism under nutrient-limited conditions. Cell Rep 2021; 36:109701. [PMID: 34525352 PMCID: PMC8500708 DOI: 10.1016/j.celrep.2021.109701] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 06/19/2021] [Accepted: 08/20/2021] [Indexed: 01/11/2023] Open
Abstract
Citrate lies at a critical node of metabolism, linking tricarboxylic acid metabolism and lipogenesis via acetyl-coenzyme A. Recent studies have observed that deficiency of the sodium-dependent citrate transporter (NaCT), encoded by SLC13A5, dysregulates hepatic metabolism and drives pediatric epilepsy. To examine how NaCT contributes to citrate metabolism in cells relevant to the pathophysiology of these diseases, we apply 13C isotope tracing to SLC13A5-deficient hepatocellular carcinoma (HCC) cells and primary rat cortical neurons. Exogenous citrate appreciably contributes to intermediary metabolism only under hypoxic conditions. In the absence of glutamine, citrate supplementation increases de novo lipogenesis and growth of HCC cells. Knockout of SLC13A5 in Huh7 cells compromises citrate uptake and catabolism. Citrate supplementation rescues Huh7 cell viability in response to glutamine deprivation or Zn2+ treatment, and NaCT deficiency mitigates these effects. Collectively, these findings demonstrate that NaCT-mediated citrate uptake is metabolically important under nutrient-limited conditions and may facilitate resistance to metal toxicity.
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Affiliation(s)
- Avi Kumar
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Thekla Cordes
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Anna E Thalacker-Mercer
- Division of Nutritional Sciences, Cornell University, Ithaca, NY 14850, USA; Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Ana M Pajor
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, La Jolla, CA 92093, USA
| | - Anne N Murphy
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, USA
| | - Christian M Metallo
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA; Moores Cancer Center, University of California, San Diego, La Jolla, CA 92037, USA.
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18
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Sun Q, Niu Q, Guo Y, Zhuang Y, Li X, Liu J, Li N, Li Z, Huang F, Qiu Z. Regulation on Citrate Influx and Metabolism through Inhibiting SLC13A5 and ACLY: A Novel Mechanism Mediating the Therapeutic Effects of Curcumin on NAFLD. J Agric Food Chem 2021; 69:8714-8725. [PMID: 34323067 DOI: 10.1021/acs.jafc.1c03105] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Upregulated de novo lipogenesis (DNL) plays a pivotal role in the progress of the nonalcoholic fatty liver disease (NAFLD). Cytoplasmic citrate flux, mediated by plasma membrane citrate transporter (SLC13A5), mitochondrial citrate carrier (SLC25A1), and ATP-dependent citrate lyase (ACLY), determines the central carbon source for acetyl-CoA required in DNL. Curcumin, a widely accepted dietary polyphenol, can attenuate lipid accumulation in NAFLD. Here, we first investigated the lipid-lowering effect of curcumin against NAFLD in oleic and palmitic acid (OPA)-induced primary mouse hepatocytes and high-fat plus high-fructose diet (HFHFD)-induced mice. Curcumin profoundly attenuated OPA- or HFHFD-induced hyperlipidemia and aberrant hepatic lipid deposition via modulating the expression and function of SLC13A5 and ACLY. The possible mechanism of curcumin on the citrate pathway was investigated using HepG2 cells, HEK293T cells transfected with human SLC13A5, and recombinant human ACLY. In OPA-stimulated HepG2 cells, curcumin rectified the dysregulated expression of SLC13A5/ACLY possibly via the AMPK-mTOR signaling pathway. Besides, curcumin also functionally inhibited both citrate transport and metabolism mediated by SLC13A5 and ACLY, respectively. These findings confirm that curcumin improves the lipid accumulation in the liver by blocking citrate disposition and hence may be used to prevent NAFLD.
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Affiliation(s)
- Qiushuang Sun
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Qun Niu
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yating Guo
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Yu Zhuang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Xiaonan Li
- Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, State University of New York at Buffalo, Buffalo, New York 14260, United States
| | - Jia Liu
- Pharmaceutical Animal Experimental Center, China Pharmaceutical University, Nanjing 210009, China
| | - Ning Li
- National Experimental Teaching Demonstration Center of Pharmacy, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zhiyu Li
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Fang Huang
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing 210009, China
| | - Zhixia Qiu
- Center of Drug Metabolism and Pharmacokinetics, School of Pharmacy, China Pharmaceutical University, Nanjing 210009, China
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19
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Ozlu C, Bailey RM, Sinnett S, Goodspeed KD. Gene Transfer Therapy for Neurodevelopmental Disorders. Dev Neurosci 2021; 43:230-240. [PMID: 33882495 DOI: 10.1159/000515434] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/13/2021] [Indexed: 11/19/2022] Open
Abstract
Neurodevelopmental disorders (NDDs) include a broad spectrum of disorders that disrupt normal brain development. Though some NDDs are caused by acquired insults (i.e., toxic or infectious encephalopathy) or may be cryptogenic, many NDDs are caused by variants in a single gene or groups of genes that disrupt neuronal development or function. In this review, we will focus on those NDDs with a genetic etiology. The exact mechanism, timing, and progression of the molecular pathology are seldom well known; however, the abnormalities in development typically manifest in similar patterns such as delays or regression in motor function, social skills, and language or cognitive abilities. Severity of impairment can vary widely. At present, only symptomatic treatments are available to manage seizures and behavioral problems commonly seen in NDDs. In recent years, there has been a rapid expansion of research into gene therapy using adeno-associated viruses (AAVs). Using AAVs as vectors to replace the non- or dysfunctional gene in vivo is a relatively simple model which has created an unprecedented opportunity for the future of NDD treatment. Advances in this field are of paramount importance as NDDs lead to a massive lifelong burden of disease on the affected individuals and families. In this article, we review the unique advantages and challenges of AAV gene therapies. We then look at potential applications of gene therapy for 3 of the more common NDDs (Rett syndrome, fragile X syndrome, and Angelman syndrome), as well as 2 less common NDDs (SLC13A5 deficiency disorder and SLC6A1-related disorder). We will review the available natural history of each disease and current state of preclinical studies including a discussion on the application of AAV gene therapies for each disease.
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Affiliation(s)
- Can Ozlu
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Rachel M Bailey
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Sarah Sinnett
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA.,Eugene McDermott Center for Human Growth and Development, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Kimberly D Goodspeed
- Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, Texas, USA
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20
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Duan R, Saadi NW, Grochowski CM, Bhadila G, Faridoun A, Mitani T, Du H, Fatih JM, Jhangiani SN, Akdemir ZC, Gibbs RA, Pehlivan D, Posey JE, Marafi D, Lupski JR. A novel homozygous SLC13A5 whole-gene deletion generated by Alu/Alu-mediated rearrangement in an Iraqi family with epileptic encephalopathy. Am J Med Genet A 2021; 185:1972-1980. [PMID: 33797191 DOI: 10.1002/ajmg.a.62192] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2020] [Revised: 02/10/2021] [Accepted: 03/05/2021] [Indexed: 01/05/2023]
Abstract
Biallelic loss-of-function (LoF) of SLC13A5 (solute carrier family 13, member 5) induced deficiency in sodium/citrate transporter (NaCT) causes autosomal recessive developmental epileptic encephalopathy 25 with hypoplastic amelogenesis imperfecta (DEE25; MIM #615905). Many pathogenic SLC13A5 single nucleotide variants (SNVs) and small indels have been described; however, no cases with copy number variants (CNVs) have been sufficiently investigated. We describe a consanguineous Iraqi family harboring an 88.5 kb homozygous deletion including SLC13A5 in Chr17p13.1. The three affected male siblings exhibit neonatal-onset epilepsy with fever-sensitivity, recurrent status epilepticus, global developmental delay/intellectual disability (GDD/ID), and other variable neurological findings as shared phenotypical features of DEE25. Two of the three affected subjects exhibit hypoplastic amelogenesis imperfecta (AI), while the proband shows no evidence of dental abnormalities or AI at 2 years of age with apparently unaffected primary dentition. Characterization of the genomic architecture at this locus revealed evidence for genomic instability generated by an Alu/Alu-mediated rearrangement; confirmed by break-point junction Sanger sequencing. This multiplex family from a distinct population elucidates the phenotypic consequence of complete LoF of SLC13A5 and illustrates the importance of read-depth-based CNV detection in comprehensive exome sequencing analysis to solve cases that otherwise remain molecularly unsolved.
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Affiliation(s)
- Ruizhi Duan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Nebal Waill Saadi
- College of Medicine, University of Baghdad, Baghdad, Iraq.,Children Welfare Teaching Hospital, Medical City Complex, Baghdad, Iraq
| | | | - Ghalia Bhadila
- Department of Advanced Oral Sciences and Therapeutics, University of Maryland School of Dentistry, Baltimore, Maryland, USA.,Department of Pediatric Dentistry, Faculty of Dentistry, King AbdulAziz University, Jeddah, Saudi Arabia
| | - Afnan Faridoun
- Department of General Dental Practice, Faculty of Dentistry, Kuwait University, Kuwait
| | - Tadahiro Mitani
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Haowei Du
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Jawid M Fatih
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Zeynep C Akdemir
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Richard A Gibbs
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA
| | - Davut Pehlivan
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA.,Section of Pediatric Neurology and Developmental Neuroscience, Department of Pediatrics, Baylor College of Medicine & Texas Children's Hospital, Houston, Texas, USA
| | - Jennifer E Posey
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA
| | - Dana Marafi
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Department of Pediatrics, Faculty of Medicine, Kuwait University, Safat, Kuwait
| | - James R Lupski
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, USA.,Human Genome Sequencing Center, Baylor College of Medicine, Houston, Texas, USA.,Texas Children's Hospital, Houston, Texas, USA.,Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
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21
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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22
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Abstract
INTRODUCTION SLC13A5-related epileptic encephalopathy is a recently described autosomal recessive disorder that is characterized by infantile epilepsy and developmental delay. Seizures are markedly drug resistant and often induced by fever; they mainly occur in clusters, sometimes evolving into status epilepticus. METHODS AND RESULTS We report the use of stiripentol as an adjunctive therapy in three siblings with drug-resistant SLC13A5-related epilepsy. The three patients showed remarkable improvement in the severity and frequency of seizures, status epilepticus, emergency department visits, and alertness. CONCLUSION These observations extend the use of stiripentol beyond the classical Dravet syndrome, and further studies on the use of this drug in drug-resistant epilepsy, mainly of genetic origin, are warranted.
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Affiliation(s)
- Afnan Alhakeem
- Divisions of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Faisal Alshibani
- Divisions of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia
| | - Brahim Tabarki
- Divisions of Pediatric Neurology, Department of Pediatrics, Prince Sultan Military Medical City, Riyadh, Saudi Arabia.
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23
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Bainbridge MN, Cooney E, Miller M, Kennedy AD, Wulff JE, Donti T, Jhangiani SN, Gibbs RA, Elsea SH, Porter BE, Graham BH. Analyses of SLC13A5-epilepsy patients reveal perturbations of TCA cycle. Mol Genet Metab 2017; 121:314-319. [PMID: 28673551 PMCID: PMC7539367 DOI: 10.1016/j.ymgme.2017.06.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Revised: 06/20/2017] [Accepted: 06/21/2017] [Indexed: 01/16/2023]
Abstract
OBJECTIVE To interrogate the metabolic profile of five subjects from three families with rare, nonsense and missense mutations in SLC13A5 and Early Infantile Epileptic Encephalopathies (EIEE) characterized by severe, neonatal onset seizures, psychomotor retardation and global developmental delay. METHODS Mass spectrometry of plasma, CSF and urine was used to identify consistently dysregulated analytes in our subjects. RESULTS Distinctive elevations of citrate and dysregulation of citric acid cycle intermediates, supporting the hypothesis that loss of SLC13A5 function alters tricarboxylic acid cycle (TCA) metabolism and may disrupt metabolic compartmentation in the brain. SIGNIFICANCE Our results indicate that analysis of plasma citrate and other TCA analytes in SLC13A5 deficient patients define a diagnostic metabolic signature that can aid in diagnosing children with this disease.
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Affiliation(s)
- Matthew N Bainbridge
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, United States; Codified Genomics LLC, Houston, TX, United States; Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, United States
| | - Erin Cooney
- Dept. of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Marcus Miller
- Dept. of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | | | | | - Taraka Donti
- Dept. of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Shalini N Jhangiani
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, United States
| | - Richard A Gibbs
- Human Genome Sequencing Center, Baylor College of Medicine, Houston, TX, United States
| | - Sarah H Elsea
- Dept. of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States
| | - Brenda E Porter
- Department of Neurology, Stanford University Medical School, Palo Alto, CA, United States
| | - Brett H Graham
- Dept. of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX, United States.
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24
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Li Z, Li D, Choi EY, Lapidus R, Zhang L, Huang SM, Shapiro P, Wang H. Silencing of solute carrier family 13 member 5 disrupts energy homeostasis and inhibits proliferation of human hepatocarcinoma cells. J Biol Chem 2017; 292:13890-13901. [PMID: 28655760 DOI: 10.1074/jbc.m117.783860] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 06/23/2017] [Indexed: 12/22/2022] Open
Abstract
The solute carrier family 13 member 5 (SLC13A5), a sodium-coupled citrate transporter, plays a key role in importing citrate from the circulation into liver cells. Recent evidence has revealed that SLC13A5 deletion protects mice from high-fat diet-induced hepatic steatosis and that mutation of the SLC13A5 orthologues in Drosophila melanogaster and Caenorhabditis elegans promotes longevity. However, despite the emerging importance of SLC13A5 in energy homeostasis, whether perturbation of SLC13A5 affects the metabolism and malignancy of hepatocellular carcinoma is unknown. Here, we sought to determine whether SLC13A5 regulates hepatic energy homeostasis and proliferation of hepatoma cells. RNAi-mediated silencing of SLC13A5 expression in two human hepatoma cell lines, HepG2 and Huh7, profoundly suppressed cell proliferation and colony formation, and induced cell cycle arrest accompanied by increased expression of cyclin-dependent kinase inhibitor p21 and decreased expression of cyclin B1. Furthermore, such suppressive effects were also observed on the growth of HepG2 cell-derived xenografts expressing SLC13A5-shRNA in nude mice. Metabolically, knockdown of SLC13A5 in HepG2 and Huh7 cells was associated with a decrease in intracellular levels of citrate, the ratio of ATP/ADP, phospholipid content, and ATP citrate lyase expression. Moreover, both in vitro and in vivo assays demonstrated that SLC13A5 depletion promotes activation of the AMP-activated protein kinase, which was accompanied by deactivation of oncogenic mechanistic target of rapamycin signaling. Together, our findings expand the role of SLC13A5 from facilitating hepatic energy homeostasis to influencing hepatoma cell proliferation and suggest a potential role of SLC13A5 in the progression of human hepatocellular carcinoma.
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Affiliation(s)
- Zhihui Li
- From the Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201
| | - Daochuan Li
- From the Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201
| | - Eun Yong Choi
- the Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Rena Lapidus
- the Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Lei Zhang
- the Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, Maryland 20993
| | - Shiew-Mei Huang
- the Office of Clinical Pharmacology, Office of Translational Sciences, Center for Drug Evaluation and Research, Food and Drug Administration (FDA), Silver Spring, Maryland 20993
| | - Paul Shapiro
- From the Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201.,the Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
| | - Hongbing Wang
- From the Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland 21201, .,the Marlene and Stewart Greenebaum Cancer Center, University of Maryland School of Medicine, Baltimore, Maryland 21201, and
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25
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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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26
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Weeke LC, Brilstra E, Braun KP, Zonneveld-Huijssoon E, Salomons GS, Koeleman BP, van Gassen KL, van Straaten HL, Craiu D, de Vries LS. Punctate white matter lesions in full-term infants with neonatal seizures associated with SLC13A5 mutations. Eur J Paediatr Neurol 2017; 21:396-403. [PMID: 27913086 DOI: 10.1016/j.ejpn.2016.11.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 11/13/2016] [Indexed: 01/03/2023]
Abstract
INTRODUCTION Early-onset epileptic encephalopathy caused by biallelic SLC13A5 mutations is characterized by seizure onset in the first days of life, refractory epilepsy and developmental delay. Little detailed information about the brain MRI features is available in these patients. METHODS Observational study describing the neuro-imaging findings in eight patients (five families) with mutations in the SLC13A5 gene. Seven infants had an MRI in the neonatal period, two had a follow-up MRI at the age of 6 and 18 months and one only at 13 months. One patient had follow-up MRIs at 11 and 16 months and 3 and 6 years of age, but no neonatal MRI. RESULTS All patients presented with refractory neonatal seizures on the first day of life after an uncomplicated pregnancy and term delivery. Six out of seven infants with a neonatal MRI had a characteristic MRI pattern, with punctate white matter lesions (PWML), which were no longer visible at the age of 6 months, but led to gliotic scarring visible on MRI at the age of 18 months. The same pattern of gliotic scarring was seen on the MRIs of the infant without a neonatal scan. One infant had signal abnormalities in the white matter suspected of PWML on T2WI, but these could not be confirmed on other sequences. CONCLUSION In infants presenting with therapy resistant seizures in the first days after birth, without a clear history of hypoxic-ischemic encephalopathy, but with PWML on their neonatal MRI, a diagnosis of SCL13A5 related epileptic encephalopathy should be considered.
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Affiliation(s)
- Lauren C Weeke
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Eva Brilstra
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Kees P Braun
- Department of Pediatric Neurology, Brain Center Rudolf Magnus, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, VU University Medical Center/Neuroscience Campus, Amsterdam, The Netherlands
| | - Bobby P Koeleman
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Koen L van Gassen
- Department of Genetics, University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Dana Craiu
- Pediatric Neurology Discipline, Department of Clinical Neurosciences, "Carol Davila" University of Medicine, Bucharest, Romania; Pediatric Neurology Clinic, Alexandru Obregia Hospital, Bucharest, Romania
| | - Linda S de Vries
- Department of Neonatology, Wilhelmina Children's Hospital, University Medical Center Utrecht, Utrecht, The Netherlands.
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27
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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