1
|
Jaramillo-Martinez V, Sennoune SR, Tikhonova EB, Karamyshev AL, Ganapathy V, Urbatsch IL. Molecular phenotypes segregate missense mutations in SLC13A5 Epilepsy. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.23.594637. [PMID: 38826402 PMCID: PMC11142175 DOI: 10.1101/2024.05.23.594637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The sodium-coupled citrate transporter (NaCT, SLC13A5) mediates citrate uptake across the plasma membrane via an inward Na + gradient. Mutations in SLC13A5 cause early infantile epileptic encephalopathy type-25 (EIEE25, SLC13A5 Epilepsy) due to impaired citrate uptake in neurons. Despite clinical identification of disease-causing mutations, underlying mechanisms and cures remain elusive. We mechanistically classify the molecular phenotypes of six mutations. C50R, T142M, and T227M exhibit impaired citrate transport despite normal expression at the cell surface. G219R, S427L, and L488P are hampered by low protein expression, ER retention, and reduced transport. Mutants' mRNA levels resemble wildtype, suggesting post-translational defects. Class II mutations display immature core-glycosylation and shortened half-lives, indicating protein folding defects. These experiments provide a comprehensive understanding of the mutation's defects in SLC13A5 Epilepsy at the biochemical and molecular level and shed light into the trafficking pathway(s) of NaCT. The two classes of mutations will require fundamentally different treatment approaches to either restore transport function, or enable correction of protein folding defects. Summary Loss-of-function mutations in the SLC13A5 causes SLC13A5-Epilepsy, a devastating disease characterized by neonatal epilepsy. Currently no cure is available. We clarify the molecular-level defects to guide future developments for phenotype-specific treatment of disease-causing mutations.
Collapse
|
2
|
Donoghue S, Wright J, Voss AK, Lockhart PJ, Amor DJ. The Mendelian disorders of chromatin machinery: Harnessing metabolic pathways and therapies for treatment. Mol Genet Metab 2024; 142:108360. [PMID: 38428378 DOI: 10.1016/j.ymgme.2024.108360] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Revised: 02/25/2024] [Accepted: 02/26/2024] [Indexed: 03/03/2024]
Abstract
The Mendelian disorders of chromatin machinery (MDCMs) represent a distinct subgroup of disorders that present with neurodevelopmental disability. The chromatin machinery regulates gene expression by a range of mechanisms, including by post-translational modification of histones, responding to histone marks, and remodelling nucleosomes. Some of the MDCMs that impact on histone modification may have potential therapeutic interventions. Two potential treatment strategies are to enhance the intracellular pool of metabolites that can act as substrates for histone modifiers and the use of medications that may inhibit or promote the modification of histone residues to influence gene expression. In this article we discuss the influence and potential treatments of histone modifications involving histone acetylation and histone methylation. Genomic technologies are facilitating earlier diagnosis of many Mendelian disorders, providing potential opportunities for early treatment from infancy. This has parallels with how inborn errors of metabolism have been afforded early treatment with newborn screening. Before this promise can be fulfilled, we require greater understanding of the biochemical fingerprint of these conditions, which may provide opportunities to supplement metabolites that can act as substrates for chromatin modifying enzymes. Importantly, understanding the metabolomic profile of affected individuals may also provide disorder-specific biomarkers that will be critical for demonstrating efficacy of treatment, as treatment response may not be able to be accurately assessed by clinical measures.
Collapse
Affiliation(s)
- Sarah Donoghue
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Biochemical Genetics, Victorian Clinical Genetics Services, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia.
| | - Jordan Wright
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| | - Anne K Voss
- Walter and Eliza Hall Institute of Medical Research, 1G Royal Parade, Parkville, Melbourne 3052, Australia; Department of Medical Biology, The University of Melbourne, Parkville 3052, Australia
| | - Paul J Lockhart
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| | - David J Amor
- Murdoch Children's Research Institute, Parkville 3052, Australia; Department of Paediatrics, The University of Melbourne, Parkville 3052, Australia
| |
Collapse
|
3
|
Zhang L, Hu W, Guo H, Sun Q, Xu X, Li Z, Qiu Z, Bian J. Discovery of Highly Potent Solute Carrier 13 Member 5 (SLC13A5) Inhibitors for the Treatment of Hyperlipidemia. J Med Chem 2024; 67:6687-6704. [PMID: 38574002 DOI: 10.1021/acs.jmedchem.4c00260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/06/2024]
Abstract
In the face of escalating metabolic disease prevalence, largely driven by modern lifestyle factors, this study addresses the critical need for novel therapeutic approaches. We have identified the sodium-coupled citrate transporter (NaCT or SLC13A5) as a target for intervention. Utilizing rational drug design, we developed a new class of SLC13A5 inhibitors, anchored by the hydroxysuccinic acid scaffold, refining the structure of PF-06649298. Among these, LBA-3 emerged as a standout compound, exhibiting remarkable potency with an IC50 value of 67 nM, significantly improving upon PF-06649298. In vitro assays demonstrated LBA-3's efficacy in reducing triglyceride levels in OPA-induced HepG2 cells. Moreover, LBA-3 displayed superior pharmacokinetic properties and effectively lowered triglyceride and total cholesterol levels in diverse mouse models (PCN-stimulated and starvation-induced), without detectable toxicity. These findings not only spotlight LBA-3 as a promising candidate for hyperlipidemia treatment but also exemplify the potential of targeted molecular design in advancing metabolic disorder therapeutics.
Collapse
Affiliation(s)
- Li'ao Zhang
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P. R. China
| | - Wenjun Hu
- Departments of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Huimin Guo
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P. R. China
| | - Qiushuang Sun
- Department of Pharmacology of Chinese Materia Medica, School of Traditional Chinese Pharmacy, Nanjing 211100, P. R. China
| | - Xi Xu
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P. R. China
| | - Zhiyu Li
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P. R. China
| | - Zhixia Qiu
- Departments of Pharmacology, School of Pharmacy, China Pharmaceutical University, Nanjing 211100, P. R. China
| | - Jinlei Bian
- Department of Medicinal Chemistry, School of Pharmacy, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, P. R. China
| |
Collapse
|
4
|
Fernandez-Fuente G, Overmyer KA, Lawton AJ, Kasza I, Shapiro SL, Gallego-Muñoz P, Coon JJ, Denu JM, Alexander CM, Puglielli L. The citrate transporters SLC13A5 and SLC25A1 elicit different metabolic responses and phenotypes in the mouse. Commun Biol 2023; 6:926. [PMID: 37689798 PMCID: PMC10492862 DOI: 10.1038/s42003-023-05311-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 09/01/2023] [Indexed: 09/11/2023] Open
Abstract
Cytosolic citrate is imported from the mitochondria by SLC25A1, and from the extracellular milieu by SLC13A5. In the cytosol, citrate is used by ACLY to generate acetyl-CoA, which can then be exported to the endoplasmic reticulum (ER) by SLC33A1. Here, we report the generation of mice with systemic overexpression (sTg) of SLC25A1 or SLC13A5. Both animals displayed increased cytosolic levels of citrate and acetyl-CoA; however, SLC13A5 sTg mice developed a progeria-like phenotype with premature death, while SLC25A1 sTg mice did not. Analysis of the metabolic profile revealed widespread differences. Furthermore, SLC13A5 sTg mice displayed increased engagement of the ER acetylation machinery through SLC33A1, while SLC25A1 sTg mice did not. In conclusion, our findings point to different biological responses to SLC13A5- or SLC25A1-mediated import of citrate and suggest that the directionality of the citrate/acetyl-CoA pathway can transduce different signals.
Collapse
Affiliation(s)
- Gonzalo Fernandez-Fuente
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Katherine A Overmyer
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Morgridge Institute for Research, Madison, WI, USA
| | - Alexis J Lawton
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Ildiko Kasza
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, USA
| | - Samantha L Shapiro
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA
| | - Patricia Gallego-Muñoz
- Department of Cell Biology, Genetics, Histology and Pharmacology, Faculty of Medicine, University of Valladolid, Valladolid, Spain
| | - Joshua J Coon
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Morgridge Institute for Research, Madison, WI, USA
- Department of Chemistry, University of Wisconsin-Madison, Madison, WI, USA
| | - John M Denu
- Department of Biomolecular Chemistry, University of Wisconsin-Madison, Madison, WI, USA
- Wisconsin Institute for Discovery, University of Wisconsin-Madison, Madison, WI, USA
| | - Caroline M Alexander
- McArdle Laboratory for Cancer Research, University of Wisconsin-Madison, Madison, WI, USA
| | - Luigi Puglielli
- Department of Medicine, University of Wisconsin-Madison, Madison, WI, USA.
- Waisman Center, University of Wisconsin-Madison, Madison, WI, USA.
- Geriatric Research Education Clinical Center, Veterans Affairs Medical Center, Madison, WI, USA.
- Department of Neuroscience, University of Wisconsin-Madison, Madison, WI, USA.
| |
Collapse
|
5
|
Carapancea E, Cilio MR. A novel approach to seizures in neonates. Eur J Paediatr Neurol 2023; 46:89-97. [PMID: 37544258 DOI: 10.1016/j.ejpn.2023.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Revised: 07/26/2023] [Accepted: 07/26/2023] [Indexed: 08/08/2023]
Abstract
THE CHALLENGE OF SEIZURE RECOGNITION Recognition of seizures in neonates remains the foremost challenge to overcome. All neonates at risk for seizures, especially the critically ill, should undergo video-EEG monitoring. The initial step toward an accurate diagnosis is the accurate description and interpretation of the electro-clinical phenotype. THE IMPORTANCE OF SEIZURE SEMIOLOGY AND ASSOCIATION WITH ETIOLOGY: The early distinction between acute provoked seizures and neonatal-onset epilepsies serves as the primary determinant for guiding management, treatment choices, and duration. Seizures in neonates should be seen as a symptom, not a disease, and their semiology may suggest the etiology. TREATMENT OF ACUTE PROVOKED SEIZURES Neonates with hypoxic-ischemic encephalopathy respond best to phenobarbital, while levetiracetam is a better choice for neonates with congenital heart diseases. Anti-seizure medication can be discontinued after 72 h of seizure freedom, before discharge from the hospital. TREATMENT OF NEONATAL EPILEPSIES Neonates with epilepsy usually require a personalized, etiology-based approach in terms of choice and duration of treatment. Neonates with channelopathies tend to respond to sodium channel blockers such as carbamazepine, oxcarbazepine, or phenytoin. The surgical option should be considered early in cases of large brain malformations, such as hemimegalencephaly.
Collapse
Affiliation(s)
- Evelina Carapancea
- Institute of Neuroscience (IoNS), Université Catholique de Louvain, Brussels, Belgium
| | - Maria Roberta Cilio
- Institute of Neuroscience (IoNS), Université Catholique de Louvain, Brussels, Belgium; Division of Pediatric Neurology, Department of Pediatrics, Cliniques Universitaires Saint-Luc, Université Catholique de Louvain, Brussels, Belgium.
| |
Collapse
|
6
|
Absalom NL, Lin SXN, Liao VWY, Chua HC, Møller RS, Chebib M, Ahring PK. GABA A receptors in epilepsy: Elucidating phenotypic divergence through functional analysis of genetic variants. J Neurochem 2023. [PMID: 37621067 DOI: 10.1111/jnc.15932] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2023] [Revised: 07/27/2023] [Accepted: 08/01/2023] [Indexed: 08/26/2023]
Abstract
Normal brain function requires a tightly regulated balance between excitatory and inhibitory neurotransmissions. γ-Aminobutyric acid type A (GABAA ) receptors represent the major class of inhibitory ion channels in the mammalian brain. Dysregulation of these receptors and/or their associated pathways is strongly implicated in the pathophysiology of epilepsy. To date, hundreds of different GABAA receptor subunit variants have been associated with epilepsy, making them a prominent cause of genetically linked epilepsy. While identifying these genetic variants is crucial for accurate diagnosis and effective genetic counselling, it does not necessarily lead to improved personalised treatment options. This is because the identification of a variant does not reveal how the function of GABAA receptors is affected. Genetic variants in GABAA receptor subunits can cause complex changes to receptor properties resulting in various degrees of gain-of-function, loss-of-function or a combination of both. Understanding how variants affect the function of GABAA receptors therefore represents an important first step in the ongoing development of precision therapies. Furthermore, it is important to ensure that functional data are produced using methodologies that allow genetic variants to be classified using clinical guidelines such as those developed by the American College of Medical Genetics and Genomics. This article will review the current knowledge in the field and provide recommendations for future functional analysis of genetic GABAA receptor variants.
Collapse
Affiliation(s)
- Nathan L Absalom
- School of Science, University of Western Sydney, Sydney, New South Wales, Australia
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Susan X N Lin
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Vivian W Y Liao
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Han C Chua
- Brain and Mind Centre, Sydney Pharmacy School, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Rikke S Møller
- Department of Epilepsy Genetics and Personalized Medicine, The Danish Epilepsy Centre, Filadelfia, Dianalund, Denmark
- Department of Regional Health Research, University of Southern Denmark, Odense, Denmark
| | - Mary Chebib
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| | - Philip K Ahring
- Brain and Mind Centre, School of Medical Sciences, Faculty of Medicine and Health, The University of Sydney, Sydney, New South Wales, Australia
| |
Collapse
|
7
|
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.
Collapse
|
8
|
Whitney R, Choi E, Jones KC. The neuroimaging spectrum of SLC13A5 related developmental and epileptic encephalopathy. Seizure 2023; 106:8-13. [PMID: 36701889 DOI: 10.1016/j.seizure.2023.01.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Revised: 12/14/2022] [Accepted: 01/18/2023] [Indexed: 01/24/2023] Open
Abstract
BACKGROUND SLC13A5 related developmental and epileptic encephalopathy (DEE) is an autosomal recessive condition characterized by neonatal seizures, fever sensitivity, status epilepticus, developmental delay and tooth anomalies. The neuroimaging spectrum of SLC13A5 related DEE is not fully known. We present a case of SLC13A5 related DEE with distinct neuroimaging findings and review the neuroimaging findings of all published cases of SLC13A5 related DEE. METHODS A retrospective case review and focused review of the literature was completed. RESULTS A 16-month-old male with a clinical phenotype consistent with SLC13A5 related DEE and a previously reported pathogenic variant in SLC13A5, c.655G>A, p.Gly219Arg and a novel likely pathogenic variant in SLC13A5, c.202C>T, p.Pro68Ser was identified. MRI at day 5 of life revealed wide spread punctate white matter lesions (PWMLs) affecting the subcortical white matter, periventricular white matter, splenium of the corpus callosum, posterior limb of the internal capsule, corticospinal tracts, midbrain, pons and medulla, mimicking a metabolic/infectious etiology. MRI at one month showed atrophy and evolution of white matter necrosis. One hundred and five cases of SLC13A5 related DEE were identified. Initial MRI was completed in 62 cases (59%). MRI was normal in 41 cases (66%) and abnormal in 21 (34%). White matter abnormalities were most common (n=15, 71%); PWMLs occurred in 8 cases (38%). CONCLUSION Neuroimaging abnormalities may exist in a third of SLC13A5 related DEE cases. White matter abnormalities such as PWMLs appear most common. It remains unknown why some are susceptible to these lesions and how they affect long-term neurodevelopmental outcomes in SLC13A5 related DEE.
Collapse
Affiliation(s)
- Robyn Whitney
- Division of Neurology, Department of Paediatrics, McMaster University, 1200 Main Street West, Hamilton, ON, Canada.
| | - Elaine Choi
- Division of Neurology, Department of Paediatrics, McMaster University, 1200 Main Street West, Hamilton, ON, Canada
| | - Kevin C Jones
- Division of Neurology, Department of Paediatrics, McMaster University, 1200 Main Street West, Hamilton, ON, Canada
| |
Collapse
|
9
|
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] [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.
Collapse
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,
| |
Collapse
|
10
|
Intracellular Citrate/acetyl-CoA flux and endoplasmic reticulum acetylation: Connectivity is the answer. Mol Metab 2022; 67:101653. [PMID: 36513219 PMCID: PMC9792894 DOI: 10.1016/j.molmet.2022.101653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 11/29/2022] [Accepted: 12/05/2022] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Key cellular metabolites reflecting the immediate activity of metabolic enzymes as well as the functional metabolic state of intracellular organelles can act as powerful signal regulators to ensure the activation of homeostatic responses. The citrate/acetyl-CoA pathway, initially recognized for its role in intermediate metabolism, has emerged as a fundamental branch of this nutrient-sensing homeostatic response. Emerging studies indicate that fluctuations in acetyl-CoA availability within different cellular organelles and compartments provides substrate-level regulation of many biological functions. A fundamental aspect of these regulatory functions involves Nε-lysine acetylation. SCOPE OF REVIEW Here, we will examine the emerging regulatory functions of the citrate/acetyl-CoA pathway and the specific role of the endoplasmic reticulum (ER) acetylation machinery in the maintenance of intracellular crosstalk and homeostasis. These functions will be analyzed in the context of associated human diseases and specific mouse models of dysfunctional ER acetylation and citrate/acetyl-CoA flux. A primary objective of this review is to highlight the complex yet integrated response of compartment- and organelle-specific Nε-lysine acetylation to the intracellular availability and flux of acetyl-CoA, linking this important post-translational modification to cellular metabolism. MAJOR CONCLUSIONS The ER acetylation machinery regulates the proteostatic functions of the organelle as well as the metabolic crosstalk between different intracellular organelles and compartments. This crosstalk enables the cell to impart adaptive responses within the ER and the secretory pathway. However, it also enables the ER to impart adaptive responses within different cellular organelles and compartments. Defects in the homeostatic balance of acetyl-CoA flux and ER acetylation reflect different but converging disease states in humans as well as converging phenotypes in relevant mouse models. In conclusion, citrate and acetyl-CoA should not only be seen as metabolic substrates of intermediate metabolism but also as signaling molecules that direct functional adaptation of the cell to both intracellular and extracellular messages. Future discoveries in CoA biology and acetylation are likely to yield novel therapeutic approaches.
Collapse
|
11
|
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] [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.
Collapse
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
| |
Collapse
|
12
|
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.
Collapse
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
| |
Collapse
|
13
|
Goodspeed K, Bailey RM, Prasad S, Sadhu C, Cardenas JA, Holmay M, Bilder DA, Minassian BA. Gene Therapy: Novel Approaches to Targeting Monogenic Epilepsies. Front Neurol 2022; 13:805007. [PMID: 35847198 PMCID: PMC9284605 DOI: 10.3389/fneur.2022.805007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 04/20/2022] [Indexed: 11/18/2022] Open
Abstract
Genetic epilepsies are a spectrum of disorders characterized by spontaneous and recurrent seizures that can arise from an array of inherited or de novo genetic variants and disrupt normal brain development or neuronal connectivity and function. Genetically determined epilepsies, many of which are due to monogenic pathogenic variants, can result in early mortality and may present in isolation or be accompanied by neurodevelopmental disability. Despite the availability of more than 20 antiseizure medications, many patients with epilepsy fail to achieve seizure control with current therapies. Patients with refractory epilepsy—particularly of childhood onset—experience increased risk for severe disability and premature death. Further, available medications inadequately address the comorbid developmental disability. The advent of next-generation gene sequencing has uncovered genetic etiologies and revolutionized diagnostic practices for many epilepsies. Advances in the field of gene therapy also present the opportunity to address the underlying mechanism of monogenic epilepsies, many of which have only recently been described due to advances in precision medicine and biology. To bring precision medicine and genetic therapies closer to clinical applications, experimental animal models are needed that replicate human disease and reflect the complexities of these disorders. Additionally, identifying and characterizing clinical phenotypes, natural disease course, and meaningful outcome measures from epileptic and neurodevelopmental perspectives are necessary to evaluate therapies in clinical studies. Here, we discuss the range of genetically determined epilepsies, the existing challenges to effective clinical management, and the potential role gene therapy may play in transforming treatment options available for these conditions.
Collapse
Affiliation(s)
- Kimberly Goodspeed
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
| | - Rachel M. Bailey
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
- Center for Alzheimer's and Neurodegenerative Diseases, University of Texas Southwestern, Dallas, TX, United States
| | - Suyash Prasad
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Chanchal Sadhu
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Jessica A. Cardenas
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Mary Holmay
- Department of Research and Development, Taysha Gene Therapies, Dallas, TX, United States
| | - Deborah A. Bilder
- Division of Child and Adolescent Psychiatry, Department of Psychiatry, Huntsman Mental Health Institute, University of Utah, Salt Lake City, UT, United States
| | - Berge A. Minassian
- Division of Child Neurology, Department of Pediatrics, University of Texas Southwestern, Dallas, TX, United States
- *Correspondence: Berge A. Minassian
| |
Collapse
|
14
|
Santalucia R, Vilain C, Soblet J, De Laet C, Vuckovic A, König J, Aeby A. Carbamazepine efficacy in a severe electro‐clinical presentation of
SLC13A5
‐epilepsy. Ann Clin Transl Neurol 2022; 9:1095-1099. [PMID: 35633140 PMCID: PMC9268890 DOI: 10.1002/acn3.51581] [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: 03/18/2022] [Revised: 05/02/2022] [Accepted: 05/04/2022] [Indexed: 12/18/2022] Open
Abstract
Recessive mutations in the SLC13A5 gene encoding the sodium‐dependent citrate transporter are a recently identified cause of developmental and epileptic encephalopathy. Here, we describe a child harboring a novel homozygous loss‐of‐function mutation in the SLC13A5 gene (c.1496C>T–p.Ser499Phe) and exhibiting an unusual extremely severe neonatal presentation with drug‐resistant seizures and burst‐suppression EEG pattern. Early carbamazepine use resulted in dramatic improvement both clinically and on EEG features. Follow‐up from the neonatal period to the age of 4 years is documented. This case expands the electro‐clinical phenotype associated with SLC13A5‐related disease and confirms the efficacy and safety of carbamazepine in nonstructural early‐onset epilepsies.
Collapse
Affiliation(s)
- Roberto Santalucia
- Pediatric Neurology Unit Cliniques Universitaires Saint‐Luc, UCLouvain Brussels Belgium
- Department of Pediatric Neurology Queen Fabiola Children's Hospital‐ULB Brussels Belgium
| | | | | | - Corinne De Laet
- Metabolic Diseases Unit Queen Fabiola Children's Hospital‐ULB Brussels Belgium
| | - Aline Vuckovic
- Neonatal Intensive Care Unit Queen Fabiola Children's Hospital‐ULB Brussels Belgium
| | - Jörg König
- Institute of Experimental and Clinical Pharmacology and Toxicology Friedrich‐Alexander‐Universität Erlangen‐Nürnberg Erlangen Germany
| | - Alec Aeby
- Department of Pediatric Neurology Queen Fabiola Children's Hospital‐ULB Brussels Belgium
| |
Collapse
|
15
|
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] [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.
Collapse
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
| |
Collapse
|
16
|
The Genetic Diagnosis of Ultrarare DEEs: An Ongoing Challenge. Genes (Basel) 2022; 13:genes13030500. [PMID: 35328054 PMCID: PMC8953579 DOI: 10.3390/genes13030500] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2022] [Revised: 03/04/2022] [Accepted: 03/10/2022] [Indexed: 02/06/2023] Open
Abstract
Epileptic encephalopathies (EEs) and developmental and epileptic encephalopathies (DEEs) are a group of severe early-onset neurodevelopmental disorders (NDDs). In recent years, next-generation equencing (NGS) technologies enabled the discovery of numerous genes involved in these conditions. However, more than 50% of patients remained undiagnosed. A major obstacle lies in the high degree of genetic heterogeneity and the wide phenotypic variability that has characterized these disorders. Interpreting a large amount of NGS data is also a crucial challenge. This study describes a dynamic diagnostic procedure used to investigate 17 patients with DEE or EE with previous negative or inconclusive genetic testing by whole-exome sequencing (WES), leading to a definite diagnosis in about 59% of participants. Biallelic mutations caused most of the diagnosed cases (50%), and a pathogenic somatic mutation resulted in 10% of the subjects. The high diagnostic yield reached highlights the relevance of the scientific approach, the importance of the reverse phenotyping strategy, and the involvement of a dedicated multidisciplinary team. The study emphasizes the role of recessive and somatic variants, new genetic mechanisms, and the complexity of genotype–phenotype associations. In older patients, WES results could end invasive diagnostic procedures and allow a more accurate transition. Finally, an early pursued diagnosis is essential for comprehensive care of patients, precision approach, knowledge of prognosis, patient and family planning, and quality of life.
Collapse
|
17
|
Sauer DB, Wang B, Sudar JC, Song J, Marden J, Rice WJ, Wang DN. The ups and downs of elevator-type di-/tricarboxylate membrane transporters. FEBS J 2022; 289:1515-1523. [PMID: 34403567 PMCID: PMC9832446 DOI: 10.1111/febs.16158] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 07/27/2021] [Accepted: 08/16/2021] [Indexed: 01/13/2023]
Abstract
The divalent anion sodium symporter (DASS) family contains both sodium-driven anion cotransporters and anion/anion exchangers. The family belongs to a broader ion transporter superfamily (ITS), which comprises 24 families of transporters, including those of AbgT antibiotic efflux transporters. The human proteins in the DASS family play major physiological roles and are drug targets. We recently determined multiple structures of the human sodium-dependent citrate transporter (NaCT) and the succinate/dicarboxylate transporter from Lactobacillus acidophilus (LaINDY). Structures of both proteins show high degrees of structural similarity to the previously determined VcINDY fold. Conservation between these DASS protein structures and those from the AbgT family indicates that the VcINDY fold represents the overall protein structure for the entire ITS. The new structures of NaCT and LaINDY are captured in the inward- or outward-facing conformations, respectively. The domain arrangements in these structures agree with a rigid body elevator-type transport mechanism for substrate translocation across the membrane. Two separate NaCT structures in complex with a substrate or an inhibitor allowed us to explain the inhibition mechanism and propose a detailed classification scheme for grouping disease-causing mutations in the human protein. Structural understanding of multiple kinetic states of DASS proteins is a first step toward the detailed characterization of their entire transport cycle.
Collapse
Affiliation(s)
- David B. Sauer
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Bing Wang
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY 10016, USA
| | - Joseph C. Sudar
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Jinmei Song
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - Jennifer Marden
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
| | - William J. Rice
- Cryo-Electron Microscopy Core, New York University School of Medicine, New York, NY 10016, USA
| | - Da-Neng Wang
- Skirball Institute of Biomolecular Medicine, New York University School of Medicine, New York, NY 10016, USA
- Department of Cell Biology, New York University School of Medicine, New York, NY 10016, USA
| |
Collapse
|
18
|
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] [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.
Collapse
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
| |
Collapse
|
19
|
AlQudairy H, AlDhalaan H, AlRuways S, AlMutairi N, AlNakiyah M, AlGhofaili R, AlBakheet A, Alomrani A, Alharbi OA, Tous E, AlSayed M, AlZaidan H, AlRasheed MM, AlOdaib A, Kaya N. Clinical, radiological, and genetic characterization of SLC13A5 variants in Saudi families: Genotype phenotype correlation and brief review of the literature. Front Pediatr 2022; 10:1051534. [PMID: 36923948 PMCID: PMC10008858 DOI: 10.3389/fped.2022.1051534] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Accepted: 12/14/2022] [Indexed: 03/03/2023] Open
Abstract
Background SLC13A5 (solute carrier family 13, member 5) encodes sodium/citrate cotransporter, which mainly localizes in cellular plasma membranes in the frontal cortex, retina, and liver. Pathogenic variants of the gene cause an autosomal recessive syndrome known as "developmental and epileptic encephalopathy 25 with amelogenesis imperfecta." Results Here, we have investigated six patients from three different consanguineous Saudi families. The affected individuals presented with neonatal seizures, developmental delay, and significant defects in tooth development. Some patients showed other clinical features such as muscle weakness, motor difficulties, intellectual disability, microcephaly, and speech problems in addition to additional abnormalities revealed by electroencephalography (EEGs) and magnetic resonance imaging (MRI). One of the MRI findings was related to cortical thickening in the frontal lobe. To diagnose and study the genetic defects of the patients, whole exome sequencing (WES) coupled with confirmatory Sanger sequencing was utilized. Iterative filtering identified two variants of SLC13A5, one of which is novel, in the families. Families 1 and 2 had the same insertion (a previously reported mutation), leading to a frameshift and premature stop codon. The third family had a novel splice site variant. Confirmatory Sanger sequencing corroborated WES results and indicated full segregation of the variants in the corresponding families. The patients' conditions were poorly controlled by multiple antiepileptics as they needed constant care. Conclusion Considering that recessive mutations are common in the Arab population, SLC13A5 screening should be prioritized in future patients harboring similar symptoms including defects in molar development.
Collapse
Affiliation(s)
- Hanan AlQudairy
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital, and Research Centre (KFSHRC), Riyadh, Saudi Arabia
| | | | - Sarah AlRuways
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital, and Research Centre (KFSHRC), Riyadh, Saudi Arabia.,College of Pharmacy, King Saud University (KSU), Riyadh, Saudi Arabia
| | - Nouf AlMutairi
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital, and Research Centre (KFSHRC), Riyadh, Saudi Arabia.,College of Pharmacy, King Saud University (KSU), Riyadh, Saudi Arabia
| | - Maha AlNakiyah
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital, and Research Centre (KFSHRC), Riyadh, Saudi Arabia.,College of Pharmacy, King Saud University (KSU), Riyadh, Saudi Arabia
| | - Reema AlGhofaili
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital, and Research Centre (KFSHRC), Riyadh, Saudi Arabia.,College of Pharmacy, King Saud University (KSU), Riyadh, Saudi Arabia
| | | | | | - Omar A Alharbi
- Department of Neurosciences, KFSHRC, Riyadh, Saudi Arabia
| | - Ehab Tous
- Department of Neurosciences, KFSHRC, Riyadh, Saudi Arabia
| | - Moeen AlSayed
- Department of Medical Genomics, Center for Genomic Medicine, KFSHRC, Riyadh, Saudi Arabia
| | - Hamad AlZaidan
- Department of Medical Genomics, Center for Genomic Medicine, KFSHRC, Riyadh, Saudi Arabia
| | - Maha M AlRasheed
- College of Pharmacy, King Saud University (KSU), Riyadh, Saudi Arabia.,Department of Clinical Pharmacy, College of Pharmacy, King Saud University, Riyadh, Saudi Arabia
| | - Ali AlOdaib
- Training and Education Department, Research Centre, KFSHRC, Riyadh, Saudi Arabia
| | - Namik Kaya
- Translational Genomic Department, Center for Genomic Medicine, King Faisal Specialist Hospital, and Research Centre (KFSHRC), Riyadh, Saudi Arabia
| |
Collapse
|
20
|
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] [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.
Collapse
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;
| |
Collapse
|
21
|
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.
Collapse
|
22
|
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] [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.
Collapse
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.
| |
Collapse
|
23
|
Pellegrino F, Tardivo I. SLC13A5-related epileptic encephalopathy successfully treated with valproate and acetazolamide. Seizure 2021; 91:244-245. [PMID: 34233239 DOI: 10.1016/j.seizure.2021.06.029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 06/14/2021] [Accepted: 06/16/2021] [Indexed: 11/18/2022] Open
Affiliation(s)
| | - Irene Tardivo
- Department of Pediatrics and Public Health, University of Turin, Turin, Italy
| |
Collapse
|
24
|
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.
Collapse
|
25
|
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] [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.
Collapse
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
| |
Collapse
|