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Wilpert NM, Tonduti D, Vaia Y, Krude H, Sarret C, Schuelke M. Establishing Patient-Centered Outcomes for MCT8 Deficiency: Stakeholder Engagement and Systematic Literature Review. Neuropsychiatr Dis Treat 2023; 19:2195-2216. [PMID: 37881807 PMCID: PMC10595182 DOI: 10.2147/ndt.s379703] [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] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Accepted: 10/07/2023] [Indexed: 10/27/2023] Open
Abstract
Introduction The SCL16A2 gene encodes the thyroid hormone (TH) transporter MCT8. Pathogenic variants result in a reduced TH uptake into the CNS despite high serum T3 concentrations. Patients suffer from severe neurodevelopmental delay and require multidisciplinary care. Since a first compassionate use study in 2008, the development of therapies has recently gained momentum. Treatment strategies range from symptom-based approaches, supplementation with TH or TH-analogs, to gene therapy. All these studies have mainly used surrogate endpoints and clinical outcomes. However, the EMA and FDA strongly encourage researchers to involve patients and their advocacy groups in the design of clinical trials. This should strengthen the patients' perspective and identify clinical endpoints that are clinically relevant to their daily life. Methods We involved patient families to define patient-relevant outcomes for MCT8 deficiency. In close collaboration with patient families, we designed a questionnaire asking for their five most preferred therapeutic goals, which, if achieved at least, make a difference in their lives. In addition, we performed a systematic review according to Cochrane recommendations of the published treatment trials. Results We obtained results from 15 families with completed questionnaires from 14 mothers and 8 fathers. Improvement in development, especially in gross motor skills, was most important to the parents. 59% wished for head control and 50% for sitting ability. Another 36% wished for weight gain, 32% for improvement of expressive language skills, and 18% for a reduction of dystonia/spasticity, less dysphagia, and reflux. Paraclinical aspects were least important (5-9%). In a treatment trial (n=46) and compassionate use cases (n=83), the results were mainly inconclusive, partly due to a lack of predefined patient-centered clinical endpoints. Discussion We recommend that future trials should define a relevant improvement in "development" and/or other patient-relevant outcomes compared to natural history as treatment goals.
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Affiliation(s)
- Nina-Maria Wilpert
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Department of Pediatric Neurology, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health (BIH), Center for Chronically Sick Children, Berlin, Germany
| | - Davide Tonduti
- Unit of Pediatric Neurology, C.O.A.L.A. (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children’s Hospital, Università Degli Studi Di Milano, Milan, Italy
| | - Ylenia Vaia
- Unit of Pediatric Neurology, C.O.A.L.A. (Center for Diagnosis and Treatment of Leukodystrophies), V. Buzzi Children’s Hospital, Università Degli Studi Di Milano, Milan, Italy
| | - Heiko Krude
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Institute of Experimental Pediatric Endocrinology, Berlin, Germany
| | - Catherine Sarret
- Centre de Compétence des Leucodystrophies et Leucoencéphalopathies de Cause Rare, Centre Hospitalier Universitaire de Clermont-Ferrand, Clermont-Ferrand, France
| | - Markus Schuelke
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), Department of Pediatric Neurology, Berlin, Germany
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität Zu Berlin, and Berlin Institute of Health (BIH), Center for Chronically Sick Children, Berlin, Germany
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health (BIH), NeuroCure Clinical Research Center, Berlin, Germany
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Chen J, Salveridou E, Liebmann L, Sundaram SM, Doycheva D, Markova B, Hübner CA, Boelen A, Visser WE, Heuer H, Mayerl S. Triac Treatment Prevents Neurodevelopmental and Locomotor Impairments in Thyroid Hormone Transporter Mct8/Oatp1c1 Deficient Mice. Int J Mol Sci 2023; 24. [PMID: 36834863 DOI: 10.3390/ijms24043452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/11/2023] Open
Abstract
Patients with inactive thyroid hormone (TH) transporter MCT8 display intellectual disability due to compromised central TH transport and action. As a therapeutic strategy, application of thyromimetic, MCT8-independent compounds Triac (3,5,3'-triiodothyroacetic acid), and Ditpa (3,5-diiodo-thyropropionic acid) was proposed. Here, we directly compared their thyromimetic potential in Mct8/Oatp1c1 double knock-out mice (Dko) modeling human MCT8 deficiency. Dko mice received either Triac (50 ng/g or 400 ng/g) or Ditpa (400 ng/g or 4000 ng/g) daily during the first three postnatal weeks. Saline-injected Wt and Dko mice served as controls. A second cohort of Dko mice received Triac (400 ng/g) daily between postnatal weeks 3 and 6. Thyromimetic effects were assessed at different postnatal stages by immunofluorescence, ISH, qPCR, electrophysiological recordings, and behavior tests. Triac treatment (400 ng/g) induced normalized myelination, cortical GABAergic interneuron differentiation, electrophysiological parameters, and locomotor performance only when administered during the first three postnatal weeks. Ditpa (4000 ng/g) application to Dko mice during the first three postnatal weeks resulted in normal myelination and cerebellar development but only mildly improved neuronal parameters and locomotor function. Together, Triac is highly-effective and more efficient than Ditpa in promoting CNS maturation and function in Dko mice yet needs to be initiated directly after birth for the most beneficial effects.
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Sundaram SM, Arrulo Pereira A, Müller-Fielitz H, Köpke H, De Angelis M, Müller TD, Heuer H, Körbelin J, Krohn M, Mittag J, Nogueiras R, Prevot V, Schwaninger M. Gene therapy targeting the blood-brain barrier improves neurological symptoms in a model of genetic MCT8 deficiency. Brain 2022; 145:4264-4274. [PMID: 35929549 DOI: 10.1093/brain/awac243] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [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: 12/08/2021] [Revised: 06/03/2022] [Accepted: 06/22/2022] [Indexed: 12/27/2022] Open
Abstract
A genetic deficiency of the solute carrier monocarboxylate transporter 8 (MCT8), termed Allan-Herndon-Dudley syndrome, is an important cause of X-linked intellectual and motor disability. MCT8 transports thyroid hormones across cell membranes. While thyroid hormone analogues improve peripheral changes of MCT8 deficiency, no treatment of the neurological symptoms is available so far. Therefore, we tested a gene replacement therapy in Mct8- and Oatp1c1-deficient mice as a well-established model of the disease. Here, we report that targeting brain endothelial cells for Mct8 expression by intravenously injecting the vector AAV-BR1-Mct8 increased tri-iodothyronine (T3) levels in the brain and ameliorated morphological and functional parameters associated with the disease. Importantly, the therapy resulted in a long-lasting improvement in motor coordination. Thus, the data support the concept that MCT8 mediates the transport of thyroid hormones into the brain and indicate that a readily accessible vascular target can help overcome the consequences of the severe disability associated with MCT8 deficiency.
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Affiliation(s)
- Sivaraj M Sundaram
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
| | - Adriana Arrulo Pereira
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
| | - Helge Müller-Fielitz
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
| | - Hannes Köpke
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
| | - Meri De Angelis
- Institute for Diabetes and Obesity, Helmholtz Zentrum Munich, Munich, and German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany.,Institute of Experimental Genetics, Helmholtz Zentrum Munich, German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Zentrum Munich, Munich, and German Center for Diabetes Research (DZD), 85764 Neuherberg, Germany
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Essen, University Duisburg-Essen, 45147 Essen, Germany
| | - Jakob Körbelin
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany.,Department of Oncology, Hematology and Bone Marrow Transplantation, UKE Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Markus Krohn
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
| | - Jens Mittag
- Institute for Endocrinology and Diabetes, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany
| | - Ruben Nogueiras
- Department of Physiology, CIMUS, University of Santiago de Compostela-Instituto de Investigación Sanitaria, 15782 Santiago de Compostela, Spain
| | - Vincent Prevot
- Université Lille, Inserm, CHU Lille, Laboratory of Development and Plasticity of the Neuroendocrine Brain, Lille Neuroscience & Cognition, UMR-S 1172, European Genomic Institute for Diabetes (EGID), 59045 Lille Cedex, France
| | - Markus Schwaninger
- Institute for Experimental and Clinical Pharmacology and Toxicology, Center of Brain, Behavior and Metabolism, University of Lübeck, 23562 Lübeck, Germany.,DZHK (German Research Centre for Cardiovascular Research), Hamburg-Lübeck-Kiel, Germany
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Refetoff S, Pappa T, Williams MK, Matheus MG, Liao XH, Hansen K, Nicol L, Pierce M, Blasco PA, Wiebers Jensen M, Bernal J, Weiss RE, Dumitrescu AM, LaFranchi S. Prenatal Treatment of Thyroid Hormone Cell Membrane Transport Defect Caused by MCT8 Gene Mutation. Thyroid 2021; 31:713-720. [PMID: 32746752 PMCID: PMC8110025 DOI: 10.1089/thy.2020.0306] [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] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Background: Mutations of the thyroid hormone (TH)-specific cell membrane transporter, monocarboxylate transporter 8 (MCT8), produce an X-chromosome-linked syndrome of TH deficiency in the brain and excess in peripheral tissues. The clinical consequences include brain hypothyroidism causing severe psychoneuromotor abnormalities (no speech, truncal hypotonia, and spastic quadriplegia) and hypermetabolism (poor weight gain, tachycardia, and increased metabolism, associated with high serum levels of the active TH, T3). Treatment in infancy and childhood with TH analogues that reduce serum triiodothyronine (T3) corrects hypermetabolism, but has no effect on the psychoneuromotor deficits. Studies of brain from a 30-week-old MCT8-deficient embryo indicated that brain abnormalities were already present during fetal life. Methods: A carrier woman with an affected male child (MCT8 A252fs268*), pregnant with a second affected male embryo, elected to carry the pregnancy to term. We treated the fetus with weekly 500 μg intra-amniotic instillation of levothyroxine (LT4) from 18 weeks of gestation until birth at 35 weeks. Thyroxine (T4), T3, and thyrotropin (TSH) were measured in the amniotic fluid and maternal serum. Treatment after birth was continued with LT4 and propylthiouracil. Follow-up included brain magnetic resonance imaging (MRI) and neurodevelopmental evaluation, both compared with the untreated brother. Results: During intrauterine life, T4 and T3 in the amniotic fluid were maintained above threefold to twofold the baseline and TSH was suppressed by 80%, while maternal serum levels remained unchanged. At birth, the infant serum T4 was 14.5 μg/dL and TSH <0.01 mU/L compared with the average in untreated MCT8-deficient infants of 5.1 μg/ and >8 mU/L, respectively. MRI at six months of age showed near-normal brain myelination compared with much reduced in the untreated brother. Neurodevelopmental assessment showed developmental quotients in receptive language and problem-solving, and gross motor and fine motor function ranged from 12 to 25 at 31 months in the treated boy and from 1 to 7 at 58 months in the untreated brother. Conclusions: This is the first demonstration that prenatal treatment improved the neuromotor and neurocognitive function in MCT8 deficiency. Earlier treatment with TH analogues that concentrate in the fetus when given to the mother may further rescue the phenotype.
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Affiliation(s)
- Samuel Refetoff
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
- Department of Pediatrics, The University of Chicago, Chicago, Illinois, USA
- Committees on Genetics, and The University of Chicago, Chicago, Illinois, USA
- Address correspondence to: Samuel Refetoff, MD, Department of Medicine, The University of Chicago, MC3090, 5841 South Maryland Avenue, Chicago, IL 60637, USA
| | - Theodora Pappa
- Department of Molecular Metabolism and Nutrition, The University of Chicago, Chicago, Illinois, USA
| | | | - M. Gisele Matheus
- Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Xiao-Hui Liao
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Karen Hansen
- Northwest Perinatal Center, Portland, Oregon, USA
| | - Lindsey Nicol
- Department of Pediatrics–Endocrinology and Oregon Health & Science University, Portland, Oregon, USA
| | - Melinda Pierce
- Department of Pediatrics–Endocrinology and Oregon Health & Science University, Portland, Oregon, USA
| | - Peter A. Blasco
- Neurodevelopmental Disabilities Doernbacher Children's Hospital, Oregon Health & Science University, Portland, Oregon, USA
| | - Mandie Wiebers Jensen
- Neurodevelopmental Disabilities Doernbacher Children's Hospital, Oregon Health & Science University, Portland, Oregon, USA
| | - Juan Bernal
- Instituto de Investigaciones Biomedicas, Consejo Superior de Investigaciones Cientificas, Universidad Autonoma de Madrid and Center for Biomedical Research on Rare Diseases, Madrid, Spain
| | - Roy E. Weiss
- Department of Medicine, University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Alexandra M. Dumitrescu
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
- Department of Molecular Metabolism and Nutrition, The University of Chicago, Chicago, Illinois, USA
| | - Stephen LaFranchi
- Department of Pediatrics–Endocrinology and Oregon Health & Science University, Portland, Oregon, USA
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van Geest FS, Gunhanlar N, Groeneweg S, Visser WE. Monocarboxylate Transporter 8 Deficiency: From Pathophysiological Understanding to Therapy Development. Front Endocrinol (Lausanne) 2021; 12:723750. [PMID: 34539576 PMCID: PMC8440930 DOI: 10.3389/fendo.2021.723750] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/11/2021] [Accepted: 08/13/2021] [Indexed: 01/18/2023] Open
Abstract
Genetic defects in the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) result in MCT8 deficiency. This disorder is characterized by a combination of severe intellectual and motor disability, caused by decreased cerebral thyroid hormone signalling, and a chronic thyrotoxic state in peripheral tissues, caused by exposure to elevated serum T3 concentrations. In particular, MCT8 plays a crucial role in the transport of thyroid hormone across the blood-brain-barrier. The life expectancy of patients with MCT8 deficiency is strongly impaired. Absence of head control and being underweight at a young age, which are considered proxies of the severity of the neurocognitive and peripheral phenotype, respectively, are associated with higher mortality rate. The thyroid hormone analogue triiodothyroacetic acid is able to effectively and safely ameliorate the peripheral thyrotoxicosis; its effect on the neurocognitive phenotype is currently under investigation. Other possible therapies are at a pre-clinical stage. This review provides an overview of the current understanding of the physiological role of MCT8 and the pathophysiology, key clinical characteristics and developing treatment options for MCT8 deficiency.
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Grijota-Martínez C, Bárez-López S, Ausó E, Refetoff S, Frey WH, Guadaño-Ferraz A. Intranasal delivery of Thyroid hormones in MCT8 deficiency. PLoS One 2020; 15:e0236113. [PMID: 32687511 PMCID: PMC7371167 DOI: 10.1371/journal.pone.0236113] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Accepted: 06/28/2020] [Indexed: 11/18/2022] Open
Abstract
Loss of function mutations in the gene encoding the thyroid hormone transporter monocarboxylate transporter 8 (MCT8) lead to severe neurodevelopmental defects in humans associated with a specific thyroid hormone phenotype manifesting high serum 3,5,3'-triiodothyronine (T3) and low thyroxine (T4) levels. Patients present a paradoxical state of peripheral hyperthyroidism and brain hypothyroidism, this last one most likely arising from impaired thyroid hormone transport across the brain barriers. The administration of thyroid hormones by delivery pathways that bypass the brain barriers, such as the intranasal delivery route, offers the possibility to improve the neurological defects of MCT8-deficient patients. In this study, the thyroid hormones T4 and T3 were administrated intranasally in different mouse models of MCT8 deficiency. We have found that, under the present formulation, intranasal administration of thyroid hormones does not increase the content of thyroid hormones in the brain and further raises the peripheral thyroid hormone levels. Our data suggests intranasal delivery of thyroid hormones is not a suitable therapeutic strategy for MCT8 deficiency, although alternative formulations could be considered in the future to improve the nose-to-brain transport.
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Affiliation(s)
- Carmen Grijota-Martínez
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Unit 708, Instituto de Salud Carlos III, Madrid, Spain
| | - Soledad Bárez-López
- Center for Biomedical Research on Rare Diseases (Ciberer), Unit 708, Instituto de Salud Carlos III, Madrid, Spain
- Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Eva Ausó
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Departamento de Óptica, Farmacología y Anatomía, Universidad de Alicante, Carretera de San Vicente del Raspeig s/n, Alicante, Spain
| | - Samuel Refetoff
- Departments of Medicine, The University of Chicago, Chicago, Illinois, United States of America
- Departments of Pediatrics, The University of Chicago, Chicago, Illinois, United States of America
- Departments of Committee on Genetics, The University of Chicago, Chicago, Illinois, United States of America
| | - William H. Frey
- HealthPartners Neuroscience Center, St. Paul, Minnesota, United States of America
- HealthPartners Institute, St. Paul, Minnesota, United States of America
| | - Ana Guadaño-Ferraz
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Unit 708, Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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Grijota-Martínez C, Bárez-López S, Gómez-Andrés D, Guadaño-Ferraz A. MCT8 Deficiency: The Road to Therapies for a Rare Disease. Front Neurosci 2020; 14:380. [PMID: 32410949 PMCID: PMC7198743 DOI: 10.3389/fnins.2020.00380] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [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: 01/28/2020] [Accepted: 03/27/2020] [Indexed: 12/17/2022] Open
Abstract
Allan-Herndon-Dudley syndrome is a rare disease caused by inactivating mutations in the SLC16A2 gene, which encodes the monocarboxylate transporter 8 (MCT8), a transmembrane transporter specific for thyroid hormones (T3 and T4). Lack of MCT8 function produces serious neurological disturbances, most likely due to impaired transport of thyroid hormones across brain barriers during development resulting in severe brain hypothyroidism. Patients also suffer from thyrotoxicity in other organs due to the presence of a high concentration of T3 in the serum. An effective therapeutic strategy should restore thyroid hormone serum levels (both T3 and T4) and should address MCT8 transporter deficiency in brain barriers and neural cells, to enable the access of thyroid hormones to target neural cells. Unfortunately, targeted therapeutic options are currently scarce and their effect is limited to an improvement in the thyrotoxic state, with no sign of any neurological improvement. The use of thyroid hormone analogs such as TRIAC, DITPA, or sobetirome, that do not require MCT8 to cross cell membranes and whose controlled thyromimetic activity could potentially restore the normal function of the affected organs, are being explored to improve the cerebral availability of these analogs. Other strategies aiming to restore the transport of THs through MCT8 at the brain barriers and the cellular membranes include gene replacement therapy and the use of pharmacological chaperones. The design of an appropriate therapeutic strategy in combination with an early diagnosis (at prenatal stages), will be key aspects to improve the devastating alterations present in these patients.
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Affiliation(s)
- Carmen Grijota-Martínez
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain.,Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain.,Department of Cell Biology, Faculty of Biology, Universidad Complutense de Madrid, Madrid, Spain
| | - Soledad Bárez-López
- Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain.,Translational Health Sciences, Dorothy Hodgkin Building, University of Bristol, Bristol, United Kingdom
| | - David Gómez-Andrés
- Pediatric Neurology, Vall d'Hebron University Hospital and VHIR (Euro-NMD, ERN-RND), Barcelona, Spain
| | - Ana Guadaño-Ferraz
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Madrid, Spain.,Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
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Krude H, Biebermann H, Schuelke M, Müller TD, Tschöp M. Allan-Herndon-Dudley-Syndrome: Considerations about the Brain Phenotype with Implications for Treatment Strategies. Exp Clin Endocrinol Diabetes 2020; 128:414-422. [PMID: 32242326 DOI: 10.1055/a-1108-1456] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Despite its first description more than 75 years ago, effective treatment for "Allan-Herndon-Dudley-Syndrome (AHDS)", an X-linked thyroid hormone transporter defect, is unavailable. Mutations in the SLC16A2 gene have been discovered to be causative for AHDS in 2004, but a comprehensive understanding of the function of the encoded protein, monocarboxylate transporter 8 (MCT8), is incomplete. Patients with AHDS suffer from neurodevelopmental delay, as well as extrapyramidal (dystonia, chorea, athetosis), pyramidal (spasticity), and cerebellar symptoms (ataxia). This suggests an affection of the pyramidal tracts, basal ganglia, and cerebellum, most likely already during fetal brain development. The function of other brain areas relevant for mood, behavior, and vigilance seems to be intact. An optimal treatment strategy should thus aim to deliver T3 to these relevant structures at the correct time points during development. A potential therapeutic strategy meeting these needs might be the delivery of T3 via a "Trojan horse mechanism" by which T3 is delivered into target cells by a thyroid hormone transporter independent T3 internalization.
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Affiliation(s)
- Heiko Krude
- Institute of Experimental Pediatric Endocrinology, Charité - Universitätsmedizin, Berlin, Germany
| | - Heike Biebermann
- Institute of Experimental Pediatric Endocrinology, Charité - Universitätsmedizin, Berlin, Germany
| | - Markus Schuelke
- Department of Neuropediatrics, Charité - Universitätsmedizin, Berlin, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Centre Munich, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
| | - Matthias Tschöp
- Division of Metabolic Diseases, Technische Universität München, Munich, Germany.,German Center for Diabetes Research (DZD), Neuherberg, Germany.,Helmholtz Zentrum München, Germany
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Abstract
Thyroid hormone transporters at the plasma membrane govern intracellular bioavailability of thyroid hormone. Monocarboxylate transporter (MCT) 8 and MCT10, organic anion transporting polypeptide (OATP) 1C1, and SLC17A4 are currently known as transporters displaying the highest specificity toward thyroid hormones. Structure-function studies using homology modeling and mutational screens have led to better understanding of the molecular basis of thyroid hormone transport. Mutations in MCT8 and in OATP1C1 have been associated with clinical disorders. Different animal models have provided insight into the functional role of thyroid hormone transporters, in particular MCT8. Different treatment strategies for MCT8 deficiency have been explored, of which thyroid hormone analogue therapy is currently applied in patients. Future studies may reveal the identity of as-yet-undiscovered thyroid hormone transporters. Complementary studies employing animal and human models will provide further insight into the role of transporters in health and disease. (Endocrine Reviews 41: 1 - 55, 2020).
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Affiliation(s)
- Stefan Groeneweg
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Ferdy S van Geest
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Robin P Peeters
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University Hospital Essen, University Duisburg-Essen, Essen, Germany
| | - W Edward Visser
- Department of Internal Medicine, Erasmus Medical Center, Rotterdam, the Netherlands Academic Center for Thyroid Diseases, Erasmus Medical Center, Rotterdam, the Netherlands
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Bárez-López S, Grijota-Martínez C, Liao XH, Refetoff S, Guadaño-Ferraz A. Intracerebroventricular administration of the thyroid hormone analog TRIAC increases its brain content in the absence of MCT8. PLoS One 2019; 14:e0226017. [PMID: 31809508 PMCID: PMC6897405 DOI: 10.1371/journal.pone.0226017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Accepted: 11/19/2019] [Indexed: 01/06/2023] Open
Abstract
Patients lacking the thyroid hormone (TH) transporter MCT8 present abnormal serum levels of TH: low thyroxine and high triiodothyronine. They also have severe neurodevelopmental defects resulting from cerebral hypothyroidism, most likely due to impaired TH transport across the brain barriers. The use of TH analogs, such as triiodothyroacetic acid (TRIAC), that can potentially access the brain in the absence of MCT8 and restore at least a subset of cerebral TH actions could improve the neurological defects in these patients. We hypothesized that direct administration of TRIAC into the brain by intracerebroventricular delivery to mice lacking MCT8 could bypass the restriction at the brain barriers and mediate TH action without causing hypermetabolism. We found that intracerebroventricular administration of therapeutic doses of TRIAC does not increase further plasma triiodothyronine or further decrease plasma thyroxine levels and does not alter TH content in the cerebral cortex. Although TRIAC content increased in the brain, it did not induce TH-mediated actions on selected target genes. Our data suggest that intracerebroventricular delivery of TRIAC has the ability to target the brain in the absence of MCT8 and should be further investigated to address its potential therapeutic use in MCT8 deficiency.
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Affiliation(s)
- Soledad Bárez-López
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Grijota-Martínez
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
- Department of Cell Biology, Faculty of Biology, Universidad Complutense de Madrid, Madrid, Spain
| | - Xiao-Hui Liao
- Department of Medicine, The University of Chicago, Chicago, Illinois, United States of America
| | - Samuel Refetoff
- Department of Medicine, The University of Chicago, Chicago, Illinois, United States of America
- Department of Pediatrics, The University of Chicago, Chicago, Illinois, United States of America
- Committee on Genetics, The University of Chicago, Chicago, Illinois, United States of America
| | - Ana Guadaño-Ferraz
- Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
- * E-mail:
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11
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Remerand G, Boespflug-Tanguy O, Tonduti D, Touraine R, Rodriguez D, Curie A, Perreton N, Des Portes V, Sarret C. Expanding the phenotypic spectrum of Allan-Herndon-Dudley syndrome in patients with SLC16A2 mutations. Dev Med Child Neurol 2019; 61:1439-1447. [PMID: 31410843 DOI: 10.1111/dmcn.14332] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 07/07/2019] [Indexed: 01/01/2023]
Abstract
The aim of the study was to redefine the phenotype of Allan-Herndon-Dudley syndrome (AHDS), which is caused by mutations in the SLC16A2 gene that encodes the brain transporter of thyroid hormones. Clinical phenotypes, brain imaging, thyroid hormone profiles, and genetic data were compared to the existing literature. Twenty-four males aged 11 months to 29 years had a mutation in SLC16A2, including 12 novel mutations and five previously described mutations. Sixteen patients presented with profound developmental delay, three had severe intellectual disability with poor language and walking with an aid, four had moderate intellectual disability with language and walking abilities, and one had mild intellectual disability with hypotonia. Overall, eight had learned to walk, all had hypotonia, 17 had spasticity, 18 had dystonia, 12 had choreoathetosis, 19 had hypomyelination, and 10 had brain atrophy. Kyphoscoliosis (n=12), seizures (n=7), and pneumopathies (n=5) were the most severe complications. This study extends the phenotypic spectrum of AHDS to a mild intellectual disability with hypotonia. Developmental delay, hypotonia, hypomyelination, and thyroid hormone profile help to diagnose patients. Clinical course depends on initial severity, with stable acquisition after infancy; this may be adversely affected by neuro-orthopaedic, pulmonary, and epileptic complications. WHAT THIS PAPER ADDS: Mild intellectual disability is associated with SLC16A2 mutations. A thyroid hormone profile with a free T3 /T4 ratio higher than 0.75 can help diagnose patients. Patients with SLC16A2 mutations present a broad spectrum of neurological phenotypes that are also observed in other hypomyelinating disorders. Axial hypotonia is a consistent feature of Allan-Herndon-Dudley syndrome and leads to specific complications.
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Affiliation(s)
- Ganaelle Remerand
- Centre de Compétence des Leucodystrophies et Leucoencéphalopathies de Cause Rare, Pôle Femme et Enfant, Hôpital Estaing, Centre Hospitalier Universitaire de Clermont-Ferrand, Clermont-Ferrand, France
| | - Odile Boespflug-Tanguy
- Centre de Référence des Leucodystrophies et Leucoencéphalopathies de Cause Rare, Service de Neurologie Pédiatrique, Hôpital Robert Debré, Assistance Publique-Hôpitaux de Paris, Paris, France.,NeuroDiderot, INSERM UMR1141, Université Paris Diderot, Paris, France
| | - Davide Tonduti
- Unit of Child Neurology, Fondazione IRCCS Istituto Neurologico Carlo Besta, Milan, Italy.,Unit of Child Neurology, V. Buzzi Children's Hospital, Milan, Italy
| | - Renaud Touraine
- Service de Génétique, Centre Hospitalier Universitaire de Saint-Etienne, Saint-Etienne, France
| | - Diana Rodriguez
- Sorbonne Université, GRC no. 19, Pathologies Congénitales du Cervelet-LeucoDystrophies, Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Paris, France.,Centre de Référence Neurogénétique, Service de Neurologie Pédiatrique, Assistance Publique-Hôpitaux de Paris, Hôpital Armand Trousseau, Paris, France
| | - Aurore Curie
- Centre de Référence des Déficiences Intellectuelles de Cause Rare, Service de Neurologie Pédiatrique, Centre Hospitalier Universitaire de Lyon, Hôpital Femme-Mère-Enfant, Lyon, France
| | - Nathalie Perreton
- CIC 1407Inserm, Centre Hospitalo-Universitaire de Lyon, Lyon, France
| | - Vincent Des Portes
- Centre de Référence des Déficiences Intellectuelles de Cause Rare, Service de Neurologie Pédiatrique, Centre Hospitalier Universitaire de Lyon, Hôpital Femme-Mère-Enfant, Lyon, France
| | - Catherine Sarret
- Centre de Compétence des Leucodystrophies et Leucoencéphalopathies de Cause Rare, Pôle Femme et Enfant, Hôpital Estaing, Centre Hospitalier Universitaire de Clermont-Ferrand, Clermont-Ferrand, France.,IGCNC, Université Clermont Auvergne, CNRS, SIGMA Clermont, Institut Pascal, Clermont-Ferrand, France
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12
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Salveridou E, Mayerl S, Sundaram SM, Markova B, Heuer H. Tissue-Specific Function of Thyroid Hormone Transporters: New Insights from Mouse Models. Exp Clin Endocrinol Diabetes 2019; 128:423-427. [PMID: 31724131 DOI: 10.1055/a-1032-8328] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Thyroid hormone (TH) transporters are required for cellular transmembrane passage of TH and are thus mandatory for proper TH metabolism and action. Consequently, inactivating mutations in TH transporters such as MCT8 or OATP1C1 can cause tissue- specific changes in TH homeostasis. As the most prominent example, patients with MCT8 mutations exhibit elevated serum T3 levels, whereas their CNS appear to be in a TH deficient state. Here, we will briefly summarize recent studies of mice lacking Mct8 alone or in combination with the TH transporters Mct10 or Oatp1c1 that shed light on many aspects and pathogenic events underlying global MCT8 deficiency and also underscore the contribution of Mct10 and Oatp1c1 in tissue-specific TH transport processes. Moreover, development of conditional knock-out mice that allow a cell-specific inactivation of TH transporters in distinct tissues, disclosed cell-specific changes in TH signaling, thereby highlighting the pathophysiological significance of local control of TH action.
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Affiliation(s)
- Eva Salveridou
- Department of Endocrinology, Diabetes and Metabolism, University of Duisburg-Essen, Essen, Germany.,Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
| | - Steffen Mayerl
- Department of Endocrinology, Diabetes and Metabolism, University of Duisburg-Essen, Essen, Germany.,MRC Centre for Regenerative Medicine, University of Edinburgh, Edinburgh, UK
| | - Sivaraj Mohana Sundaram
- Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany.,Institute of Experimental and Clinical Pharmacology and Toxicology, University of Lübeck, Lübeck, Germany
| | - Boyka Markova
- Department of Endocrinology, Diabetes and Metabolism, University of Duisburg-Essen, Essen, Germany.,Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University of Duisburg-Essen, Essen, Germany.,Leibniz Research Institute for Environmental Medicine (IUF), Düsseldorf, Germany
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13
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Rurale G, Cicco ED, Dentice M, Salvatore D, Persani L, Marelli F, Luongo C. Thyroid Hormone Hyposensitivity: From Genotype to Phenotype and Back. Front Endocrinol (Lausanne) 2019; 10:912. [PMID: 32038483 PMCID: PMC6992580 DOI: 10.3389/fendo.2019.00912] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2019] [Accepted: 12/16/2019] [Indexed: 01/24/2023] Open
Abstract
Thyroid hormone action defects (THADs) have been classically considered conditions of impaired sensitivity to thyroid hormone (TH). They were originally referring to alterations in TH receptor genes (THRA and THRB), but the discovery of genetic mutations and polymorphisms causing alterations in cell membrane transport (e.g., MCT8) and metabolism (e.g., SECISBP2, DIO2) led recently to a new and broader definition of TH hyposensitivity (THH), including not only THADs but all defects that could interfere with the activity of TH. Due to the different functions and tissue-specific expression of these genes, affected patients exhibit highly variable phenotypes. Some of them are characterized by a tissue hypothyroidism or well-recognizable alterations in the thyroid function tests (TFTs), whereas others display a combination of hypo- and hyperthyroid manifestations with normal or only subtle biochemical defects. The huge effort of basic research has greatly aided the comprehension of the molecular mechanisms underlying THADs, dissecting the morphological and functional alterations on target tissues, and defining the related-changes in the biochemical profile. In this review, we describe different pictures in which a specific alteration in the TFTs (TSH, T4, and T3 levels) is caused by defects in a specific gene. Altogether these findings can help clinicians to early recognize and diagnose THH and to perform a more precise genetic screening and therapeutic intervention. On the other hand, the identification of new genetic variants will allow the generation of cell-based and animal models to give novel insight into thyroid physiology and establish new therapeutic interventions.
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Affiliation(s)
- Giuditta Rurale
- Division of Endocrine and Metabolic Diseases, IRCCS Istituto Auxologico Italiano, Milan, Italy
| | - Emery Di Cicco
- Department of Clinical Medicine & Surgery, University of Naples Federico II, Naples, Italy
| | - Monica Dentice
- Department of Clinical Medicine & Surgery, University of Naples Federico II, Naples, Italy
| | - Domenico Salvatore
- Department of Public Health, University of Naples Federico II, Naples, Italy
| | - Luca Persani
- Division of Endocrine and Metabolic Diseases, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
| | - Federica Marelli
- Division of Endocrine and Metabolic Diseases, IRCCS Istituto Auxologico Italiano, Milan, Italy
- Department of Clinical Sciences and Community Health, University of Milan, Milan, Italy
- *Correspondence: Federica Marelli
| | - Cristina Luongo
- Department of Public Health, University of Naples Federico II, Naples, Italy
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14
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Abstract
BACKGROUND Loss of function mutations in the thyroid hormone (TH)-specific cell membrane transporter, the monocarboxylate transporter 8 (MCT8), lead to profound psychomotor retardation and abnormal TH serum levels, with low thyroxine (T4) and high triiodothyronine (T3). Several studies point to impaired TH transport across brain barriers as a crucial pathophysiological mechanism resulting in cerebral hypothyroidism. Treatment options for MCT8-deficient patients are limited and are focused on overcoming the brain barriers. The aim of this study was to evaluate the ability of the TH analog sobetirome and its prodrug Sob-AM2 to access the brain and exert thyromimetic actions in the absence of Mct8. METHODS Juvenile wild-type (Wt) mice and mice lacking Mct8 and deiodinase type 2 (Mct8/Dio2KO) were treated systemically with daily injections of vehicle, 1 mg of sobetirome/kg body weight/day, or 0.3 mg of Sob-AM2/kg body weight/day for seven days. Sobetirome content was measured using liquid chromatography-tandem mass spectrometry, and T4 and T3 levels by specific radioimmunoassays. The effect of sobetirome treatment in the expression of T3-dependent genes was measured in the heart, liver, and cerebral cortex by real-time polymerase chain reaction. RESULTS Sob-AM2 treatment in Mct8/Dio2KO animals led to 1.8-fold more sobetirome content in the brain and 2.5-fold less in plasma in comparison to the treatment with the parent drug sobetirome. Both sobetirome and Sob-AM2 treatments in Mct8/Dio2KO mice greatly decreased plasma T4 and T3 levels. Dio1 and Ucp2 gene expression was altered in the liver of Mct8/Dio2KO mice and was not affected by the treatments. In the heart, Hcn2 but not Atp2a2 expression was increased after treatment with the analogs. Interestingly, both sobetirome and Sob-AM2 treatments increased the expression of several T3-dependent genes in the brain such as Hr, Abcd2, Mme, and Flywch2 in Mct8/Dio2KO mice. CONCLUSIONS Sobetirome and its amide prodrug Sob-AM2 can access the brain in the absence of Mct8 and exert thyromimetic actions modulating the expression of T3-dependent genes. At the peripheral level, the administration of these TH analogs results in the depletion of circulating T4 and T3. Therefore, sobetirome and Sob-AM2 have the potential to address the cerebral hypothyroidism and the peripheral hyperthyroidism characteristic of MCT8 deficiency.
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Affiliation(s)
- Soledad Bárez-López
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Unit 708, Instituto de Salud Carlos III, Madrid, Spain
| | - Meredith D. Hartley
- Department of Physiology and Pharmacology and Program in Chemical Biology, Oregon Health and Science University, Portland, Oregon
| | - Carmen Grijota-Martínez
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Thomas S. Scanlan
- Department of Physiology and Pharmacology and Program in Chemical Biology, Oregon Health and Science University, Portland, Oregon
- Address correspondence to:Thomas S. Scanlan, PhDDepartment of Physiology and Pharmacology and Program in Chemical BiologyOregon Health and Science UniversityPortland, OR 97239
| | - Ana Guadaño-Ferraz
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Unit 708, Instituto de Salud Carlos III, Madrid, Spain
- Ana Guadaño-Ferraz, PhDDepartment of Endocrine and Nervous System PathophysiologyInstituto de Investigaciones Biomédicas Alberto SolsConsejo Superior de Investigaciones Científicas-Universidad Autónoma de MadridArturo Duperier 4E-28029 MadridSpain
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15
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Abstract
Allan-Herndon-Dudley syndrome is a rare X-linked neurologic condition caused by mutations in monocarboxylate transporter 8 ( MCT8), which leads to deficient thyroid hormone transport. Typical features include severe cognitive impairment, truncal hypotonia, spastic paraplegia, weakness, and speech difficulties. Minimal literature exists describing the ocular findings in patients with Allan-Herndon-Dudley syndrome. We describe 4 male siblings affected with Allan-Herndon-Dudley syndrome with a novel nonsense mutation (Q90X) in the MCT8 protein. All affected siblings presented with classic findings of Allan-Herndon-Dudley syndrome, and each of the siblings also developed intermittent esotropia. This group of affected siblings represents the first consistent documentation of strabismus in Allan-Herndon-Dudley syndrome, suggesting a possible association between this clinical finding and the neurologic syndrome.
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Affiliation(s)
- Cole J Swiston
- 1 Gundersen Health System, Department of Ophthalmology, Lacrosse, WI, USA
| | - David L Nash
- 1 Gundersen Health System, Department of Ophthalmology, Lacrosse, WI, USA
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16
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17
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Abstract
Transport of thyroid hormone (TH) across the plasma membrane is essential for intracellular TH metabolism and action, and this is mediated by specific transporter proteins. During the last two decades several transporters capable of transporting TH have been identified, including monocarboxylate transporter 8 (MCT8), MCT10 and organic anion transporting polypeptide 1C1 (OATP1C1). In particular MCT8 and OATP1C1 are important for the regulation of local TH activity in the brain and thus for brain development. MCT8 is a protein containing 12 transmembrane domains, and is encoded by the SLC16A2 gene located on the X chromosome. It facilitates both TH uptake and efflux across the cell membrane. Male subjects with hemizygous mutations in MCT8 are afflicted with severe intellectual and motor disability, also known as the Allan-Herndon-Dudley syndrome (AHDS), which goes together with low serum T4 and high T3 levels. This review concerns molecular and clinical aspects of MCT8 function.
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Affiliation(s)
- Stefan Groeneweg
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
| | - W Edward Visser
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
| | - Theo J Visser
- Department of Internal Medicine, Erasmus University Medical Center, Rotterdam, The Netherlands.
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18
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Novara F, Groeneweg S, Freri E, Estienne M, Reho P, Matricardi S, Castellotti B, Visser WE, Zuffardi O, Visser TJ. Clinical and Molecular Characteristics of SLC16A2 (MCT8) Mutations in Three Families with the Allan-Herndon-Dudley Syndrome. Hum Mutat 2017; 38:260-264. [PMID: 27805744 DOI: 10.1002/humu.23140] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [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: 04/06/2016] [Revised: 10/18/2016] [Accepted: 10/21/2016] [Indexed: 11/11/2022]
Abstract
Mutations in the thyroid hormone transporter SLC16A2 (MCT8) cause the Allan-Herndon-Dudley Syndrome (AHDS), characterized by severe psychomotor retardation and peripheral thyrotoxicosis. Here, we report three newly identified AHDS patients. Previously documented mutations were identified in probands 1 (p.R271H) and 2 (p.G564R), resulting in a severe clinical phenotype. A novel mutation (p.G564E) was identified in proband 3, affecting the same Gly564 residue, but resulting in a relatively mild clinical phenotype. Functional analysis in transiently transfected COS-1 and JEG-3 cells showed a near-complete inactivation of TH transport for p.G564R, whereas considerable cell-type-dependent residual transport activity was observed for p.G564E. Both mutants showed a strong decrease in protein expression levels, but differentially affected Vmax and Km values of T3 transport. Our findings illustrate that different mutations affecting the same residue may have a differential impact on SLC16A2 transporter function, which translates into differences in severity of the clinical phenotype.
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Affiliation(s)
- Francesca Novara
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Stefan Groeneweg
- Department of Internal Medicine and Rotterdam Thyroid Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Elena Freri
- Department of Pediatric Neuroscience, Foundation I.R.C.C.S. Neurological Institute "C. Besta", Milan, Italy
| | - Margherita Estienne
- Department of Pediatric Neuroscience, Foundation I.R.C.C.S. Neurological Institute "C. Besta", Milan, Italy
| | - Paolo Reho
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Sara Matricardi
- Department of Pediatric Neuroscience, Foundation I.R.C.C.S. Neurological Institute "C. Besta", Milan, Italy.,Department of Pediatrics, University of Chieti, Chieti, Italy
| | - Barbara Castellotti
- SOSD Genetica delle Malattie Neurodegenerative e Metaboliche, U.O Patologia Clinica, Foundation I.R.C.C.S. Neurological Institute "C. Besta", Milan, Italy
| | - W Edward Visser
- Department of Internal Medicine and Rotterdam Thyroid Center, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Orsetta Zuffardi
- Department of Molecular Medicine, University of Pavia, Pavia, Italy
| | - Theo J Visser
- Department of Internal Medicine and Rotterdam Thyroid Center, Erasmus University Medical Center, Rotterdam, The Netherlands
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19
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Duarte JD, Desai AA, Sysol JR, Abbasi T, Patel AR, Lang RM, Gupta A, Garcia JGN, Gordeuk VR, Machado RF. Genome-Wide Analysis Identifies IL-18 and FUCA2 as Novel Genes Associated with Diastolic Function in African Americans with Sickle Cell Disease. PLoS One 2016; 11:e0163013. [PMID: 27636371 PMCID: PMC5026353 DOI: 10.1371/journal.pone.0163013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 09/01/2016] [Indexed: 02/06/2023] Open
Abstract
Background Diastolic dysfunction is common in sickle cell disease (SCD), and is associated with an increased risk of mortality. However, the molecular pathogenesis underlying this development is poorly understood. The aim of this study was to identify a gene expression profile that is associated with diastolic function in SCD, potentially elucidating molecular mechanisms behind diastolic dysfunction development. Methods Diastolic function was measured via echocardiography in 65 patients with SCD from two independent study populations. Gene expression microarray data was compared with diastolic function in both study cohorts. Candidate genes that associated in both analyses were tested for validation in a murine SCD model. Lastly, genotyping array data from the replication cohort was used to derive cis-expression quantitative trait loci (cis-eQTLs) and genetic associations within the candidate gene regions. Results Transcriptome data from both patient cohorts implicated 7 genes associated with diastolic function, and mouse SCD myocardial expression validated 3 of these genes. Genetic associations and eQTLs were detected in 2 of the 3 genes, FUCA2 and IL18. Conclusions FUCA2 and IL18 are associated with diastolic function in SCD patients, and may be involved in the pathogenesis of the disease. Genetic polymorphisms within the FUCA2 and IL18 gene regions are also associated with diastolic function in SCD, likely by affecting expression levels of the genes.
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Affiliation(s)
- Julio D. Duarte
- Department of Pharmacy Practice, University of Illinois at Chicago, Chicago, IL, United States of America
- * E-mail: (JDD); (RFM)
| | - Ankit A. Desai
- Division of Cardiology, Sarver Heart Center, University of Arizona, Tucson, AZ, United States of America
| | - Justin R. Sysol
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Taimur Abbasi
- Department of Medicine, Mercy Hospital and Medical Center, Chicago, IL, United States of America
| | - Amit R. Patel
- Department of Medicine, University of Chicago, Chicago, IL United States of America
| | - Roberto M. Lang
- Department of Medicine, University of Chicago, Chicago, IL United States of America
| | - Akash Gupta
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Joe G. N. Garcia
- Department of Medicine, University of Arizona, Tucson, AZ, United States of America
| | - Victor R. Gordeuk
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
| | - Roberto F. Machado
- Department of Medicine, University of Illinois at Chicago, Chicago, IL, United States of America
- * E-mail: (JDD); (RFM)
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20
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Iwayama H, Liao XH, Braun L, Bárez-López S, Kaspar B, Weiss RE, Dumitrescu AM, Guadaño-Ferraz A, Refetoff S. Adeno Associated Virus 9-Based Gene Therapy Delivers a Functional Monocarboxylate Transporter 8, Improving Thyroid Hormone Availability to the Brain of Mct8-Deficient Mice. Thyroid 2016; 26:1311-9. [PMID: 27432638 PMCID: PMC5036314 DOI: 10.1089/thy.2016.0060] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND MCT8 gene mutations produce thyroid hormone (TH) deficiency in the brain, causing severe neuropsychomotor abnormalities not correctable by treatment with TH. This proof-of-concept study examined whether transfer of human MCT8 (hMCT8) cDNA using adeno-associated virus 9 (AAV9) could correct the brain defects of Mct8 knockout mice (Mct8KO). METHODS AAV9 vectors delivering long and/or short hMCT8 protein isoforms or an empty vector were injected intravenously (IV) and/or intracerebroventricularly (ICV) into postnatal day 1 Mct8KO and wild type (Wt) mice. Triiodothyronine (T3) was given daily for four days before postnatal day 28, at which time brains were collected after perfusion to assess increase in T3 content and effect on the T3-responsive transcription factor, Hairless. RESULTS Increased pup mortality was observed after IV injection of the AAV9-long hMCT8 isoform, but not after injection of AAV9-short hMCT8 isoform. Compared to IV, ICV delivery produced more hMCT8 mRNA and protein relative to the viral dose, which was present in various brain regions and localized to the cell membranes. Despite production of abundant hMCT8 mRNA and protein with ICV delivery, only IV delivered AAV9-hMCT8 targeted the choroid plexus and significantly increased brain T3 content and expression of Hairless. CONCLUSIONS These results indicate that MCT8 delivery to brain barriers by IV but not ICV injection is crucial for its proper function. MCT8 has no constitutive activity but acts through an increase in T3 entering the brain tissue. Increasing MCT8 expression in brain cell membranes, including neurons, is insufficient to produce an effect without an increase in brain T3 content. The correct hMCT8 isoform along with an optimized delivery method are critical for an effective gene therapy to provide functional MCT8 in the brain of patients with MCT8 mutations.
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Affiliation(s)
- Hideyuki Iwayama
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Xiao-Hui Liao
- Department of Medicine, The University of Chicago, Chicago, Illinois
| | - Lyndsey Braun
- Research Institute at Nationwide Children's Hospital, Columbus, Ohio
- Department of Neuroscience, The Ohio State University, Columbus, Ohio
| | - Soledad Bárez-López
- Institute for Biomedical Research “Alberto Sols,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
| | - Brian Kaspar
- Research Institute at Nationwide Children's Hospital, Columbus, Ohio
- Department of Neuroscience, The Ohio State University, Columbus, Ohio
| | - Roy E. Weiss
- Department of Medicine, University of Miami, Miami, Florida
| | | | - Ana Guadaño-Ferraz
- Institute for Biomedical Research “Alberto Sols,” Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid, Madrid, Spain
- Center for Biomedical Research on Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
| | - Samuel Refetoff
- Department of Medicine, The University of Chicago, Chicago, Illinois
- Department of Pediatrics, The University of Chicago, Chicago, Illinois
- Department of Committee on Genetics, The University of Chicago, Chicago, Illinois
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21
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Affiliation(s)
- W Edward Visser
- 1 Department of Internal Medicine, Erasmus Medical Center , Rotterdam, The Netherlands
| | - Heike Heuer
- 2 Leibniz Research Institute for Environmental Medicine , Düsseldorf, Germany
| | - Theo J Visser
- 1 Department of Internal Medicine, Erasmus Medical Center , Rotterdam, The Netherlands
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22
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Bárez-López S, Obregon MJ, Martínez-de-Mena R, Bernal J, Guadaño-Ferraz A, Morte B. Effect of Triiodothyroacetic Acid Treatment in Mct8 Deficiency: A Word of Caution. Thyroid 2016; 26:618-26. [PMID: 26701289 DOI: 10.1089/thy.2015.0388] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Monocarboxylate transporter 8 (MCT8) is a thyroid hormone-specific cell membrane transporter. Mutations in the MCT8 gene lead to profound psychomotor retardation and abnormal thyroid hormone serum levels with low thyroxine (T4) and high triiodothyronine (T3). Currently, therapeutic options for patients are limited. Triiodothyroacetic acid (TRIAC) has potential therapeutic value. The aim of this study was to evaluate the effects and efficacy of therapeutic doses of TRIAC on Mct8-deficient mice (Mct8KO). METHODS Wild-type (Wt) and Mct8KO mice were treated with 30 ng TRIAC/g of body weight/day, given in drinking water, from postnatal day 21 to 30. TRIAC, T4 and T3 levels in plasma, as well as T3 and TRIAC content in the cerebral cortex and striatum were measured by specific radioimmunoassays. The activities of deiodinases 1 and 2 were measured in liver and cortex. The effect of TRIAC treatment in the expression of T3-dependent genes was measured in the heart, cerebral cortex, and striatum. RESULTS Plasma TRIAC concentration were the same in Wt and Mct8KO animals after treatment. TRIAC treatment greatly decreased plasma T4 in Wt and Mct8KO mice, and reduced T3 to normal levels in the Mct8KO mice. Deiodinase 1 activity and gene expression in the liver increased, while it did not have any effect on the expression of Serca2a in the heart. TRIAC treatment did not induce the expression of T3-dependent genes in the cerebral cortex or striatum, but further decreased expression of Flywch2 in the cortex and Aldh1a1 and Flywch2 in the striatum. Direct measurements of TRIAC and T3 content in the cortex and striatum revealed a decrease in T3 after treatment with no significant increase in the level of endogenous TRIAC. CONCLUSIONS Therapeutic doses of TRIAC in Mct8KO mice restored plasma T3 levels but severely decreased T4 levels. TRIAC has a direct effect on deiodinase 1 in the liver and does not have an effect on gene expression in the heart. The increase in the plasma TRIAC levels after treatment is not sufficient to increase TRIAC levels in the brain and to promote the expression of T3-dependent genes in brain cells. Instead, it leads to a state of brain hypothyroidism with reduced T3 content.
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Affiliation(s)
- Soledad Bárez-López
- 1 Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- 2 Department of Endocrine, U-708, Center for Biomedical Research on Rare Diseases (Ciberer) , Instituto de Salud Carlos III, Madrid, Spain
| | - Maria Jesus Obregon
- 1 Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Raquel Martínez-de-Mena
- 1 Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Juan Bernal
- 1 Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- 2 Department of Endocrine, U-708, Center for Biomedical Research on Rare Diseases (Ciberer) , Instituto de Salud Carlos III, Madrid, Spain
| | - Ana Guadaño-Ferraz
- 1 Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- 2 Department of Endocrine, U-708, Center for Biomedical Research on Rare Diseases (Ciberer) , Instituto de Salud Carlos III, Madrid, Spain
| | - Beatriz Morte
- 1 Department of Endocrine and Nervous System Pathophysiology, Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- 2 Department of Endocrine, U-708, Center for Biomedical Research on Rare Diseases (Ciberer) , Instituto de Salud Carlos III, Madrid, Spain
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23
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Ono E, Ariga M, Oshima S, Hayakawa M, Imai M, Ochiai Y, Mochizuki H, Namba N, Ozono K, Miyata I. Three novel mutations of the MCT8 (SLC16A2) gene: individual and temporal variations of endocrinological and radiological features. Clin Pediatr Endocrinol 2016; 25:23-35. [PMID: 27212794 PMCID: PMC4860513 DOI: 10.1297/cpe.25.23] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2015] [Accepted: 12/17/2015] [Indexed: 11/13/2022] Open
Abstract
We performed genetic analysis and clinical investigations for three patients with
suspected monocarboxylate transporter 8 (MCT8) deficiency. On genetic analysis of the
MCT8(SLC16A2) gene, novel mutations (c.1333C>A;
p.R445S, c.587G>A; p.G196E and c.1063_1064insCTACC; p.R355PfsX64) were identified in
each of three patients. Although thyroid function tests (TFTs) showed the typical pattern
of MCT8 deficiency at the time of genetic diagnosis in all patients, two patients
occasionally were euthyroid. A TRH test revealed low response, exaggerated response and
normal response of TSH, respectively. Endocrinological studies showed gonadotropin (Gn)
deficiency in two adult patients. On ultrasonography, goiter was detected in one patient.
Interestingly, pituitary magnetic resonance imaging (MRI) demonstrated atrophy and
thinness of the pituitary gland in two patients. Our findings suggest that thyroid status
in patients with MCT8 deficiency varies with time of examination, and repeated TFTs are
necessary for patients suspected of MCT8 deficiency before genetic analysis. In addition,
it is noteworthy that some variations were observed on the TRH test and ultrasonography of
the thyroid gland in the present study. Morphological abnormality of the pituitary gland
may be found in some patients, while Gn deficiency should be considered as one of the
complications.
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Affiliation(s)
- Erina Ono
- Department of Pediatrics, The Jikei University School of Medicine, Tokyo, Japan; Department of Pediatrics, Tokyo Metropolitan Kita Medical and Rehabilitation Center for the Disabled, Tokyo, Japan
| | - Masamichi Ariga
- Department of Pediatrics, Tokyo Metropolitan Kita Medical and Rehabilitation Center for the Disabled, Tokyo, Japan
| | - Sakiko Oshima
- Department of Pediatrics, Tokyo Metropolitan Kita Medical and Rehabilitation Center for the Disabled, Tokyo, Japan
| | - Mika Hayakawa
- Department of Pediatrics, Tokyo Metropolitan Kita Medical and Rehabilitation Center for the Disabled, Tokyo, Japan
| | - Masayuki Imai
- Department of Pediatrics, Tokyo Metropolitan Kita Medical and Rehabilitation Center for the Disabled, Tokyo, Japan
| | - Yukikatsu Ochiai
- Department of Pediatrics, Tokyo Metropolitan Kita Medical and Rehabilitation Center for the Disabled, Tokyo, Japan
| | - Hiroshi Mochizuki
- Department of Endocrinology and Metabolism, Saitama Children's Medical Center, Saitama, Japan
| | - Noriyuki Namba
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Keiichi Ozono
- Department of Pediatrics, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Ichiro Miyata
- Department of Pediatrics, The Jikei University School of Medicine, Tokyo, Japan
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24
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Kim JH, Kim YM, Yum MS, Choi JH, Lee BH, Kim GH, Yoo HW. Clinical and endocrine features of two Allan-Herndon-Dudley syndrome patients with monocarboxylate transporter 8 mutations. Horm Res Paediatr 2016; 83:288-92. [PMID: 25896225 DOI: 10.1159/000371466] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 12/09/2014] [Indexed: 11/19/2022] Open
Abstract
The monocarboxylate transporter 8 (MCT8) gene, located on chromosome Xq13.2, encodes a thyroid hormone transporter that is involved in triiodothyronine (T3) uptake into central neurons. MCT8 mutations cause an X-linked syndromic disorder known as Allan-Herndon-Dudley syndrome (AHDS) that is characterized by severe psychomotor delays, abnormal thyroid function, and hypomyelinated leukodystrophies. We identified 2 AHDS patients with developmental delays, truncal hypotonia, and spastic paraplegia. These patients presented with psychomotor retardation and characteristic thyroid function abnormalities, such as elevated T3 and low T4 levels. Direct MCT8 sequencing identified heterozygous mutations in each patient: p.I114N and p.A224V, respectively. Because it is difficult to suspect AHDS solely according to neurological features, thyroid function, including the T3 level, should be screened in male patients with X-linked mental retardation. Although the clinical features of hypothyroidism cannot be improved by only administering levothyroxine treatment, early diagnosis, management, and appropriate genetic counseling should be provided to at-risk families.
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Affiliation(s)
- Ja Hye Kim
- Division of Pediatric Endocrinology and Metabolism, Asan Medical Center Children's Hospital, University of Ulsan College of Medicine, Seoul, South Korea
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25
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Abstract
Monocarboxylate transporter 8 (MCT8) is a thyroid hormone transmembrane transporter expressed in many cell types, including neurons. Mutations that inactivate transport activity of MCT8 cause severe X-linked psychomotor retardation in male patients, a syndrome originally described as the Allan-Herndon-Dudley syndrome. Treatment options currently explored the focus on finding thyroid hormone-like compounds that bypass MCT8 and enter cells through different transporters. Because MCT8 is a multipass transmembrane protein, some pathogenic mutations affect membrane trafficking while potentially retaining some transporter activity. We explore here the effects of chemical and pharmacological chaperones on the expression and transport activity of the MCT8 mutant ΔPhe501. Dimethylsulfoxide, 4-phenylbutyric acid as well as its sodium salt, and the isoflavone genistein increase T3 uptake into MDCK1 cells stably transfected with mutant MCT8-ΔPhe501. We show that ΔPhe501 represents a temperature-sensitive mutant protein that is stabilized by the proteasome inhibitor MG132. 4-Phenylbutyrate has been used to stabilize ΔPhe508 mutant cystic fibrosis transmembrane conductance regulator protein and is in clinical use in patients with urea cycle defects. Genistein is enriched in soy and available as a nutritional supplement. It is effective in stabilizing MCT8-ΔPhe501 at 100 nM concentration. Expression of the L471P mutant is increased in response to phenylbutyrate, but T3 uptake activity is not induced, supporting the notion that the chaperone specifically increases membrane expression. Our findings suggest that certain pathogenic MCT8 mutants may be responsive to (co-)treatment with readily available compounds, which increase endogenous protein function.
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Affiliation(s)
- Doreen Braun
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität, 53115 Bonn, Germany
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität, 53115 Bonn, Germany
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26
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Wémeau JL. The expanding spectrum of thyroid hormone resistance concerns the entire medical field. Presse Med 2015; 44:1093-5. [PMID: 26615083 DOI: 10.1016/j.lpm.2015.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Affiliation(s)
- Jean-Louis Wémeau
- CHRU de Lille, clinique endocrinologique Marc-Linquette, service d'endocrinologie et des maladies métaboliques, 59037 Lille cedex, France.
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Kersseboom S, Horn S, Visser WE, Chen J, Friesema ECH, Vaurs-Barrière C, Peeters RP, Heuer H, Visser TJ. In vitro and mouse studies supporting therapeutic utility of triiodothyroacetic acid in MCT8 deficiency. Mol Endocrinol 2015; 28:1961-70. [PMID: 25389909 DOI: 10.1210/me.2014-1135] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Monocarboxylate transporter 8 (MCT8) transports thyroid hormone (TH) across the plasma membrane. Mutations in MCT8 result in the Allan-Herndon-Dudley syndrome, comprising severe psychomotor retardation and elevated serum T3 levels. Because the neurological symptoms are most likely caused by a lack of TH transport into the central nervous system, the administration of a TH analog that does not require MCT8 for cellular uptake may represent a therapeutic strategy. Here, we investigated the therapeutic potential of the biologically active T3 metabolite Triac (TA3) by studying TA3 transport, metabolism, and action both in vitro and in vivo. Incubation of SH-SY5Y neuroblastoma cells and MO3.13 oligodendrocytes with labeled substrates showed a time-dependent uptake of T3 and TA3. In intact SH-SY5Y cells, both T3 and TA3 were degraded by endogenous type 3 deiodinase, and they influenced gene expression to a similar extent. Fibroblasts from MCT8 patients showed an impaired T3 uptake compared with controls, whereas TA3 uptake was similar in patient and control fibroblasts. In transfected cells, TA3 did not show significant transport by MCT8. Most importantly, treatment of athyroid Pax8-knockout mice and Mct8/Oatp1c1-double knockout mice between postnatal days 1 and 12 with TA3 restored T3-dependent neural differentiation in the cerebral and cerebellar cortex, indicating that TA3 can replace T3 in promoting brain development. In conclusion, we demonstrated uptake of TA3 in neuronal cells and in fibroblasts of MCT8 patients and similar gene responses to T3 and TA3. This indicates that TA3 bypasses MCT8 and may be used to improve the neural status of MCT8 patients.
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Affiliation(s)
- Simone Kersseboom
- Department of Internal Medicine (S.K., W.E.V., E.C.H.F., R.P.P., T.J.V.) and Rotterdam Thyroid Center (S.K., W.E.V., R.P.P., T.J.V.), Erasmus University Medical Center, 3015 CN Rotterdam, The Netherlands; Leibniz Institute for Age Research/Fritz Lipmann Institute (S.H., J.C., H.H.), Jena, Germany; Inserm (C.V.-B.), Unité Mixte de Recherche (UMR) 1103, and Centre National de la Recherche Scientifique (C.V.-B.), UMR6293, F-63001 Clermont-Ferrand, France; Clermont Université (C.V.-B.), Université d'Auvergne, Laboratoire GReD, BP 10448, F-63000 Clermont-Ferrand, France; and Leibniz Research Institute for Environmental Medicine (J.C., H.H.), Düsseldorf, Germany
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28
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Anık A, Kersseboom S, Demir K, Catlı G, Yiş U, Böber E, van Mullem A, van Herebeek REA, Hız S, Abacı A, Visser TJ. Psychomotor retardation caused by a defective thyroid hormone transporter: report of two families with different MCT8 mutations. Horm Res Paediatr 2015; 82:261-71. [PMID: 25247785 DOI: 10.1159/000365191] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/10/2014] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Monocarboxylate transporter 8 (MCT8) is essential for thyroid hormone (TH) transport in the brain. Mutations in MCT8 are associated with the Allan-Herndon-Dudley syndrome (AHDS), characterized by severe psychomotor retardation and altered serum thyroid parameters. Here we report two novel mutations in MCT8 and discuss the clinical findings. CASE REPORT AND RESULTS We describe 4 males with AHDS from two unrelated families varying in age from 1.5 to 11 years. All 4 patients presented with typical clinical signs of AHDS, including severe psychomotor retardation, axial hypotonia, lack of speech, diminished muscle mass, increased muscle tone, hyperreflexia, myopathic facies, high T3, low T4 and rT3, and normal/mildly elevated TSH levels. Comparison of patients at different ages suggests the progressive nature of AHDS. Genetic analyses identified a novel missense MCT8 mutation (p.G495A) in family 1 and a 2.8-kb deletion comprising exons 3 and 4 in family 2. Functional analysis of p.G495A revealed impaired TH transport varying from 20 to 85% depending on the cell context. CONCLUSION Here we report 4 AHDS patients in unrelated Turkish families harboring novel MCT8 mutations. Despite the widely different mutations, the clinical phenotypes are very similar and findings support the progressive nature of AHDS.
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Affiliation(s)
- Ahmet Anık
- Department of Pediatric Endocrinology, Dokuz Eylul University, Izmir, Turkey
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29
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Langley KG, Trau S, Bean LJH, Narravula A, Schrier Vergano SA. A 7-month-old male with Allan-Herndon-Dudley syndrome and the power of T3. Am J Med Genet A 2015; 167A:1117-20. [DOI: 10.1002/ajmg.a.36970] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/24/2014] [Indexed: 11/06/2022]
Affiliation(s)
- Katherine G. Langley
- Department of Pediatrics; Eastern Virginia Medical School; Norfolk Virginia
- Division of Medical Genetics and Metabolism; Children's Hospital of The King's Daughters; Norfolk Virginia
| | - Steven Trau
- Department of Pediatrics; Eastern Virginia Medical School; Norfolk Virginia
| | - Lora J. H. Bean
- Department of Human Genetics; Emory University; Atlanta Georgia
| | | | - Samantha A. Schrier Vergano
- Department of Pediatrics; Eastern Virginia Medical School; Norfolk Virginia
- Division of Medical Genetics and Metabolism; Children's Hospital of The King's Daughters; Norfolk Virginia
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30
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Rodrigues F, Grenha J, Ortez C, Nascimento A, Morte B, M-Belinchón M, Armstrong J, Colomer J. Hypotonic male infant and MCT8 deficiency - a diagnosis to think about. BMC Pediatr 2014; 14:252. [PMID: 25284458 PMCID: PMC4287395 DOI: 10.1186/1471-2431-14-252] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2014] [Accepted: 10/01/2014] [Indexed: 11/17/2022] Open
Abstract
Background Thyroid hormone is crucial in the development of different organs, particularly the brain. MCT8 is a specific transporter of triiodothyronine (T3) hormone and MCT8 gene mutations cause a rare X-linked disorder named MCT8 deficiency, also known as Allan-Herndon-Dudley syndrome, characterized by psychomotor retardation and hypotonia. Typically, elevation of T3 and delayed myelination in cerebral magnetic resonance imaging are found. Case presentation We present a 24-month-old boy, born from non-consanguineous healthy parents, with severe motor and cognitive delay and global hypotonia, being unable to hold head upright or sit without support. Deep tendon reflexes were absent bilaterally at the ankles. T3 was elevated and thyroxine slightly decreased, consistent with MCT8 deficiency. Genetic studies confirmed the diagnosis. Conclusions Although a rare disease (MCT8 mutations have been reported in about 50 families all around the world), we illustrate the importance of excluding Allan-Herndon-Dudley syndrome in the evaluation of floppy male infants with development delay, without history of perinatal asphyxia. The simple evaluation of thyroid status, including T3, T4 and TSH can guide the diagnosis, avoiding a number of useless, expensive and invasive investigations and allowing appropriate genetic counseling to the affected families.
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Affiliation(s)
- Filipa Rodrigues
- Neuromuscular Unit, Neurology Department, Fundación Sant Joan de Déu, Hospital Materno-Infantil Sant Joan de Déu, Passeig Sant Joan de Déu, 2, 08950 Esplugues de Llobregat, Barcelona, Spain.
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31
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Ferrara AM, Liao XH, Gil-Ibáñez P, Bernal J, Weiss RE, Dumitrescu AM, Refetoff S. Placenta passage of the thyroid hormone analog DITPA to male wild-type and Mct8-deficient mice. Endocrinology 2014; 155:4088-93. [PMID: 25051435 PMCID: PMC4164925 DOI: 10.1210/en.2014-1085] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Monocarboxylate transporter 8 (MCT8) deficiency causes severe X-linked intellectual and neuropsychological impairment associated with abnormal thyroid function tests (TFTs) producing thyroid hormone (TH) deprivation in brain and excess in peripheral tissues. The TH analog diiodothyropropionic acid (DITPA) corrected the TFTs abnormalities and hypermetabolism of MCT8-deficient children but did not improve the neurological phenotype. The latter result was attributed to the late initiation of treatment. Therefore, we gave DITPA to pregnant mice carrying Mct8-deficient embryos to determine whether DITPA, when given prenatally, crosses the placenta and affects the serum TFTs and cerebral cortex of embryos. After depletion of the endogenous TH, Mct8-heterozygous pregnant dams carrying both wild-type (Wt) and Mct8-deficient (Mct8KO) male embryos were given DITPA. Effects were compared with those treated with levothyroxine (L-T4). With DITPA treatment, serum DITPA concentration was not different in the two genotypes, which produced equal effect on serum TSH levels in both groups of pups. In contrast, with L-T4 treatment, TSH did not normalize in Mct8KO pups whereas it did in the Wt littermates and dams despite higher concentration of serum T4. Finally, both treatments similarly modulated the expression of the TH-dependent genes Shh, Klf9, and Aldh1a3 in brain. Thus, the ability of DITPA to cross the placenta, its thyromimetic action on the expression of TH-dependent genes in brain, and its better accessibility to the pituitary than L-T4, as assessed by serum TSH, make DITPA a candidate for the prenatal treatment of MCT8 deficiency.
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Affiliation(s)
- Alfonso Massimiliano Ferrara
- Departments of Medicine (A.M.F., X.-H.L., P.G.-I., R.E.W., A.M.D., S.R.) and Pediatrics (R.E.W., S.R.) and the Committee on Genetics (S.R.), The University of Chicago, Chicago, Illinois 60637; and Instituto de Investigaciones Biomédicas and Center for Biomedical Research on Rare Diseases (P.G-I., J.B.), Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, 28029 Madrid, Spain
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Abstract
Normal thyroid metabolism is essential for human development, including the formation and functioning of the central and peripheral nervous system. Disorders of thyroid metabolism are increasingly recognized within the spectrum of paediatric neurological disorders. Both hypothyroid and hyperthyroid disease states (resulting from genetic and acquired aetiologies) can lead to characteristic neurological syndromes, with cognitive delay, extrapyramidal movement disorders, neuropsychiatric symptoms, and neuromuscular manifestations. In this review, the neurological manifestations of genetic disorders of thyroid metabolism are outlined, with particular focus on Allan-Herndon-Dudley syndrome and benign hereditary chorea. We report in detail the clinical features, major neurological and neuropsychiatric manifestations, molecular genetic findings, disease mechanisms, and therapeutic strategies for these emerging genetic 'brain-thyroid' disorders.
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Affiliation(s)
- Manju A Kurian
- Developmental Neurosciences, UCL-Institute of Child HealthLondon, UK,Department of Neurology, Great Ormond Street Hospital for ChildrenLondon, UK,Correspondence to Manju Kurian, Institute of Child Health, Level 1 CMGU Room 111, 30 Guilford Street, London WC1N 1EH, UK. E-mail:
| | - Heinz Jungbluth
- Department of Paediatric Neurology, Evelina Children's Hospital, Guy's & St Thomas' NHS Foundation TrustLondon, UK,Randall Division for Cell and Molecular Biophysics, Muscle Signalling Section, King's College LondonLondon, UK,Clinical Neuroscience Division, Institute of Psychiatry, King's College LondonLondon, UK
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33
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Abstract
The description of two novel human defects in the last ten years has uncovered new aspects of thyroid hormone physiology with regard to cell-membrane transport and intracellular metabolism. Mutations in the X-linked monocarboxylate transporter 8 (MCT8) gene result in an invalidating neurodevelopmental phenotype in males and pathognomonic thyroid functions tests with high T3, low rT3, low or low normal T4, and normal or slightly high TSH. Recessive mutations in the selenocysteine insertion sequence binding protein 2 (SBP2) gene present a variable clinical phenotype depending on the severity of the defect and its consequences on the selenoprotein hierarchy. Most characteristic is the thyroid phenotype of low serum T3, high T4, high rT3, and slightly elevated TSH levels. Herein we review all known cases of MCT8 and SBP2 deficiency and describe each disease in terms of the clinical, biochemical, genetic, and therapeutic aspects.
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Affiliation(s)
- Jiao Fu
- Department of Medicine, University of Chicago Medical Center, 5841 S. Maryland Avenue MC3090, Room M369, Chicago, IL 60637, USA; Department of Endocrinology, The First Affiliated Hospital of Xi'an Jiaotong University School of Medicine, Xi'an 710061, People's Republic of China.
| | - Alexandra M Dumitrescu
- Department of Medicine, University of Chicago Medical Center, 5841 S. Maryland Avenue MC3090, Room M369, Chicago, IL 60637, USA.
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34
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Abstract
The thyroid hormone (TH) plays a significant role in diverse processes related to growth, development, differentiation, and metabolism. TH signaling modulates energy expenditure through both central and peripheral pathways. At the cellular level, the TH exerts its effects after concerted mechanisms facilitate binding to the TH receptor. In the hypothalamus, signals from a range of metabolic pathways, including appetite, temperature, afferent stimuli via the autonomic nervous system, availability of energy substrates, hormones, and other biologically active molecules, converge to maintain plasma TH at the appropriate level to preserve energy homeostasis. At the tissue level, TH actions on metabolism are controlled by transmembrane transporters, deiodinases, and TH receptors. In the modern environment, humans are susceptible to an energy surplus, which has resulted in an obesity epidemic and, thus, understanding the contribution of the TH to cellular and organism metabolism is increasingly relevant.
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Affiliation(s)
- Elizabeth A McAninch
- Division of Endocrinology, Diabetes, and Metabolism, University of Miami Miller School of Medicine, Miami, Florida
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35
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Di Cosmo C, Liao XH, Ye H, Ferrara AM, Weiss RE, Refetoff S, Dumitrescu AM. Mct8-deficient mice have increased energy expenditure and reduced fat mass that is abrogated by normalization of serum T3 levels. Endocrinology 2013; 154:4885-95. [PMID: 24029243 PMCID: PMC3836073 DOI: 10.1210/en.2013-1150] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Children with monocarboxylate transporter 8 (MCT8) deficiency lose weight, even when adequately nourished. Changes in serum markers of thyroid hormone (TH) action compatible with thyrotoxicosis suggested that this might be due to T3 excess in peripheral tissues. Mct8-deficient mice (Mct8KO) replicate the human thyroid phenotype and are thus suitable for metabolic studies so far unavailable in humans. In the current work, compared with wild-type (Wt) mice, Mct8KO mice were leaner due to reduced fat mass. They tended to use more carbohydrates and fewer lipids during the dark phase. Mct8KO mice had increased total energy expenditure (TEE) and food and water intake, with normal total activity, indicating hypermetabolism. To determine whether this is due to the high serum T3, we studied mice deficient in both Mct8 and deiodinase 1 (Mct8D1KO) with serum T3 similar to Wt mice and Wt mice given L-T3 to raise their serum T3 to the level of Mct8KO mice. Contrary to Mct8KO, Mct8D1KO mice had similar fat mass, TEE, and food intake as their D1KO littermates, whereas T3-treated Wt mice showed increased food intake and TEE, similar to Mct8KO mice. In skeletal muscle, Mct8KO mice had increased T3 content and TH action and increased glucose metabolism, which improved in Mct8D1KO mice. These studies indicate that the high serum T3 in MCT8 deficiency increases the TEE and fails to maintain weight despite adequate calorie intake. This is mediated by tissues that are not predominantly MCT8 dependent for TH transport, including skeletal muscle. Normalizing serum T3 level by deleting deiodinase 1 corrects body composition and the metabolic alterations caused by the MCT8 deficiency.
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Affiliation(s)
- Caterina Di Cosmo
- MD, PhD, The University of Chicago, MC3090, 5841 South Maryland Avenue, Chicago, Illinois 60637.
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Visser WE, van Mullem AAA, Visser TJ, Peeters RP. Different causes of reduced sensitivity to thyroid hormone: diagnosis and clinical management. Clin Endocrinol (Oxf) 2013; 79:595-605. [PMID: 23834164 DOI: 10.1111/cen.12281] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Revised: 06/05/2013] [Accepted: 07/01/2013] [Indexed: 11/30/2022]
Abstract
Normal thyroid hormone (TH) metabolism and action require adequate cellular TH signalling. This entails proper function of TH transporters in the plasma membrane, intracellular deiodination of TH and action of the bioactive hormone T3 at its nuclear receptors (TRs). The present review summarizes the discoveries of different syndromes with reduced sensitivity at the cellular level. Mutations in the TH transporter MCT8 cause psychomotor retardation and abnormal thyroid parameters. Mutations in the SBP2 protein, which is required for normal deiodination, give rise to a multisystem disorder including abnormal thyroid function tests. Mutations in TRβ1 are a well-known cause of resistance to TH with mostly a mild phenotype, while only recently, patients with mutations in TRα1 were identified. The latter patients have slightly abnormal TH levels, growth retardation and cognitive defects. This review will describe the mechanisms of disease, clinical phenotype, diagnostic testing and suggestions for treatment strategies for each of these syndromes.
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Affiliation(s)
- W Edward Visser
- Department of Internal Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands
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Abstract
PURPOSE OF REVIEW This review summarizes the most significant findings over the last year regarding human and animal models deficient in thyroid hormone cell-membrane transporters (THCMTs). Although several THCMTs have been modelled in genetically engineered mice, the only THCMT defect known in humans is that caused by mutations in the monocarboxylate transporter 8 (MCT8) gene. RECENT FINDINGS The importance of several amino acid residues has been assessed in vitro to further our understanding on the structure-function of the MCT8. The administration of the thyromimetic compound, diiodothyropropionic acid, has been tested in patients with MCT8 gene mutations, following studies of its use in mice. Another thyroid hormone analogue, 3,3',5,5'-tetraiodothyroacetic acid, was tested in Mct8-deficient mice. The phenotypes of L-type aminoacid transporter 2 and organic anion transporting polypeptide 1C1 deficiencies have been studied in mouse models. Mct8/organic anion transporting polypeptide 1C1 double knockout mice have been shown to manifest neurodevelopmental deficits. Zebrafish is emerging as another vertebrate model that may be useful to study the role of Mct8 in brain development. SUMMARY Studies on the pathogenesis and therapy of MCT8 deficiency are in progress, and new vertebrate models that are suitable to study the neurological consequences of the syndrome are being explored.
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Affiliation(s)
- Jiao Fu
- Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Samuel Refetoff
- Departments of Medicine, Pediatrics and Genetics, The University of Chicago, Chicago, Illinois, USA
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Visser WE, Vrijmoeth P, Visser FE, Arts WFM, van Toor H, Visser TJ. Identification, functional analysis, prevalence and treatment of monocarboxylate transporter 8 (MCT8) mutations in a cohort of adult patients with mental retardation. Clin Endocrinol (Oxf) 2013; 78:310-5. [PMID: 22924588 DOI: 10.1111/cen.12023] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/07/2012] [Revised: 06/26/2012] [Accepted: 08/20/2012] [Indexed: 01/23/2023]
Abstract
OBJECTIVE Monocarboxylate transporter 8 (MCT8) is an essential thyroid hormone (TH) transporter as humans with MCT8 mutations have severe neurological and endocrine abnormalities. The objectives are (i) to identify novel MCT8 mutations and (ii) to assess their functional relevance; (iii) to describe the effects of block-and-replace treatment in an MCT8 patient. DESIGN The TOP-R study is a cross-sectional nation-wide multicentre study. PATIENTS Subjects with unexplained mental retardation (MR) were screened for MCT8 mutations. RESULTS We identified three mutations: p.F501del (previously described), p.L492P and p.T162T. The F501del and L492P mutants, but not the T162T mutant, showed diminished T3, T4 and rT3 transport in transfected cells. TH transport in T162T fibroblasts was also not affected. One patient was treated with block-and-replace therapy to normalize serum TH levels. The results indicated a slow onset of the decrease in serum T4 and T3 by successive treatment with methimazole and PTU, and eventually their complete normalization by administration of LT4 with PTU but not with methimazole. The frequency of MCT8 mutations in males with X-linked MR approximately 3·9%. CONCLUSIONS We identified several MCT8 mutations in a cohort of subjects with unexplained MR. We demonstrated the pathogenicity of two missense mutations. The synonymous variant did not affect TH transport. Block-and-replace therapy of one patient reversed the TH abnormalities. Our data suggest a decreased TH secretion rate and an increased T4 to T3 conversion by the type I deiodinase in patients with MCT8 mutations. Our study indicates that MCT8 mutations are a relatively frequent cause of X-linked MR.
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Affiliation(s)
- W Edward Visser
- Department of Internal Medicine, Erasmus Medical Center, Dr Molewaterplein 50, Rotterdam, The Netherlands
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Horn S, Kersseboom S, Mayerl S, Müller J, Groba C, Trajkovic-Arsic M, Ackermann T, Visser TJ, Heuer H. Tetrac can replace thyroid hormone during brain development in mouse mutants deficient in the thyroid hormone transporter mct8. Endocrinology 2013; 154:968-79. [PMID: 23307789 DOI: 10.1210/en.2012-1628] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The monocarboxylate transporter 8 (MCT8) plays a critical role in mediating the uptake of thyroid hormones (THs) into the brain. In patients, inactivating mutations in the MCT8 gene are associated with a severe form of psychomotor retardation and abnormal serum TH levels. Here, we evaluate the therapeutic potential of the TH analog 3,5,3',5'-tetraiodothyroacetic acid (tetrac) as a replacement for T(4) in brain development. Using COS1 cells transfected with TH transporter and deiodinase constructs, we could show that tetrac, albeit not being transported by MCT8, can be metabolized to the TH receptor active compound 3,3',5-triiodothyroacetic acid (triac) by type 2 deiodinase and inactivated by type 3 deiodinase. Triac in turn is capable of replacing T(3) in primary murine cerebellar cultures where it potently stimulates Purkinje cell development. In vivo effects of tetrac were assessed in congenital hypothyroid Pax8-knockout (KO) and Mct8/Pax8 double-KO mice as well as in Mct8-KO and wild-type animals after daily injection of tetrac (400 ng/g body weight) during the first postnatal weeks. This treatment was sufficient to promote TH-dependent neuronal differentiation in the cerebellum, cerebral cortex, and striatum but was ineffective in suppressing hypothalamic TRH expression. In contrast, TSH transcript levels in the pituitary were strongly down-regulated in response to tetrac. Based on our findings we propose that tetrac administration offers the opportunity to provide neurons during the postnatal stage with a potent TH receptor agonist, thereby eventually reducing the neurological damage in patients with MCT8 mutations without deteriorating the thyrotoxic situation in peripheral tissues.
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Affiliation(s)
- Sigrun Horn
- Leibniz Institute for Age Research/Fritz Lipmann Institute, D-07745 Jena, Germany
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Verge CF, Konrad D, Cohen M, Di Cosmo C, Dumitrescu AM, Marcinkowski T, Hameed S, Hamilton J, Weiss RE, Refetoff S. Diiodothyropropionic acid (DITPA) in the treatment of MCT8 deficiency. J Clin Endocrinol Metab 2012; 97:4515-23. [PMID: 22993035 PMCID: PMC3513545 DOI: 10.1210/jc.2012-2556] [Citation(s) in RCA: 97] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Monocarboxylate transporter 8 (MCT8) is a thyroid hormone-specific cell membrane transporter. MCT8 deficiency causes severe psychomotor retardation and abnormal thyroid tests. The great majority of affected children cannot walk or talk, and all have elevated serum T(3) levels, causing peripheral tissue hypermetabolism and inability to maintain weight. Treatment with thyroid hormone is ineffective. In Mct8-deficient mice, the thyroid hormone analog, diiodothyropropionic acid (DITPA), does not require MCT8 to enter tissues and could be an effective alternative to thyroid hormone treatment in humans. OBJECTIVE The objective of the study was to evaluate the effect and efficacy of DITPA in children with MCT8 deficiency. METHODS This was a multicenter report of four affected children given DITPA on compassionate grounds for 26-40 months. Treatment was initiated at ages 8.5-25 months, beginning with a small dose of 1.8 mg, increasing to a maximal 30 mg/d (2.1-2.4 mg/kg · d), given in three divided doses. RESULTS DITPA normalized the elevated serum T(3) and TSH when the dose reached 1 mg/kg · d and T(4) and rT(3) increased to the lower normal range. The following significant changes were also observed: decline in SHBG (in all subjects), heart rate (in three of four), and ferritin (in one of four). Cholesterol increased in two subjects. There was no weight loss and weight gain occurred in two. None of the treated children required a gastric feeding tube or developed seizures. No adverse effects were observed. CONCLUSION DITPA (1-2 mg/kg · d) almost completely normalizes thyroid tests and reduces the hypermetabolism and the tendency for weight loss. The effects of earlier commencement and long-term therapy remain to be determined.
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Affiliation(s)
- Charles F Verge
- Department of Endocrinology, Sydney Children's Hospital, Randwick, NSW 2031, Australia
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Dumitrescu AM, Refetoff S. The syndromes of reduced sensitivity to thyroid hormone. Biochim Biophys Acta Gen Subj 2012; 1830:3987-4003. [PMID: 22986150 DOI: 10.1016/j.bbagen.2012.08.005] [Citation(s) in RCA: 134] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 08/06/2012] [Accepted: 08/07/2012] [Indexed: 11/19/2022]
Abstract
BACKGROUND Six known steps are required for the circulating thyroid hormone (TH) to exert its action on target tissues. For three of these steps, human mutations and distinct phenotypes have been identified. SCOPE OF REVIEW The clinical, laboratory, genetic and molecular characteristics of these three defects of TH action are the subject of this review. The first defect, recognized 45years ago, produces resistance to TH and carries the acronym, RTH. In the majority of cases it is caused by TH receptor β gene mutations. It has been found in over 3000 individuals belonging to approximately 1000 families. Two relatively novel syndromes presenting reduced sensitivity to TH involve membrane transport and metabolism of TH. One of them, caused by mutations in the TH cell-membrane transporter MCT8, produces severe psychomotor defects. It has been identified in more than 170 males from 90 families. A defect of the intracellular metabolism of TH in 10 individuals from 8 families is caused by mutations in the SECISBP2 gene required for the synthesis of selenoproteins, including TH deiodinases. MAJOR CONCLUSIONS Defects at different steps along the pathway leading to TH action at cellular level can manifest as reduced sensitivity to TH. GENERAL SIGNIFICANCE Knowledge of the molecular mechanisms involved in TH action allows the recognition of the phenotypes caused by defects of TH action. Once previously known defects have been ruled out, new molecular defects could be sought, thus opening the avenue for novel insights in thyroid physiology. This article is part of a Special Issue entitled Thyroid hormone signaling.
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Abstract
Thyroid hormone (TH) metabolism and action via binding to nuclear receptors are intracellular events that require the passage of TH across the plasma membrane. This process is mediated by specific TH transporters of which the monocarboxylate transporter 8 (Mct8) has received major attention. Mct8 is highly expressed in different tissues such as liver, kidney, thyroid, pituitary and brain. In humans, inactivating mutations of the MCT8 gene (SLC16A2) are associated with severe forms of psychomotor retardation and abnormal TH serum levels (Allan-Herndon-Dudley syndrome). Surprisingly, Mct8 knockout (ko) mice do not exhibit overt neurological symptoms but fully replicate the unusual serum TH profile with highly increased serum T3 in the presence of low serum T4. In order to evaluate the underlying mechanisms for these abnormalities, TH transport and metabolism have been intensively studied in different tissues of Mct8 ko mice. Here, we summarize the observed changes within the hypothalamus-pituitary-thyroid axis that result in altered TH production and secretion. Although analysis of Mct8 ko mice has greatly expanded our knowledge, many open questions still remain to be addressed in order to define the tissue- and cell-specific role of this important TH transporter.
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Affiliation(s)
| | - Heike Heuer
- *Heike Heuer, PhD, Leibniz Institute for Age Research/Fritz Lipmann Institute e.V., Beutenbergstrasse 11, DE–07745 Jena (Germany), Tel. +49 3641 65 6021, E-Mail
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Heuer H, Visser TJ. The pathophysiological consequences of thyroid hormone transporter deficiencies: Insights from mouse models. Biochim Biophys Acta Gen Subj 2012; 1830:3974-8. [PMID: 22543196 DOI: 10.1016/j.bbagen.2012.04.009] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2012] [Revised: 04/04/2012] [Accepted: 04/11/2012] [Indexed: 10/28/2022]
Abstract
BACKGROUND As a prerequisite for thyroid hormone (TH) metabolism and action TH has to be transported into cells where TH deiodinases and receptors are located. The trans-membrane passage of TH is facilitated by TH transporters of which the monocarboxylate transporter MCT8 has been most intensively studied. Inactivating mutations in the gene encoding MCT8 are associated with a severe form of psychomotor retardation and abnormal serum TH levels (Allan-Herndon-Dudley syndrome). In order to define the underlying pathogenic mechanisms, Mct8 knockout mice have been generated and intensively studied. Most surprisingly, Mct8 ko mice do not show any neurological symptoms but fully replicate the abnormal serum thyroid state. SCOPE OF REVIEW We will summarize the findings of these mouse studies that shed light on various aspects of Mct8 deficiency and unambiguously demonstrated the pivotal role of Mct8 in mediating TH transport in various tissues. These studies have also revealed the presence of the complex interplay between different pathogenic mechanisms that contribute to the generation of the abnormal TH serum profile. MAJOR CONCLUSIONS Most importantly, studies of Mct8 ko mice indicated the presence of additional TH transporters that act in concert with Mct8. Interesting candidates for such a function are the L-type amino acid transporters Lat1 and Lat2 as well as the organic anion transporting polypeptide Oatp1c1. GENERAL SIGNIFICANCE Overall, the analysis of Mct8 deficient mice has greatly expanded our knowledge about the (patho-) physiological function of this transporter and established a sound basis for the characterization of additional TH transporter candidates. This article is part of a Special Issue entitled Thyroid hormone signalling.
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Affiliation(s)
- Heike Heuer
- Leibniz Institute for Age Research/Fritz Lipmann Institute, Jena, Germany.
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Vantyghem MC, Dobbelaere D, Mention K, Wemeau JL, Saudubray JM, Douillard C. Endocrine manifestations related to inherited metabolic diseases in adults. Orphanet J Rare Dis 2012; 7:11. [PMID: 22284844 PMCID: PMC3349544 DOI: 10.1186/1750-1172-7-11] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Accepted: 01/28/2012] [Indexed: 02/07/2023] Open
Abstract
Most inborn errors of metabolism (IEM) are recessive, genetically transmitted diseases and are classified into 3 main groups according to their mechanisms: cellular intoxication, energy deficiency, and defects of complex molecules. They can be associated with endocrine manifestations, which may be complications from a previously diagnosed IEM of childhood onset. More rarely, endocrinopathies can signal an IEM in adulthood, which should be suspected when an endocrine disorder is associated with multisystemic involvement (neurological, muscular, hepatic features, etc.). IEM can affect all glands, but diabetes mellitus, thyroid dysfunction and hypogonadism are the most frequent disorders. A single IEM can present with multiple endocrine dysfunctions, especially those involving energy deficiency (respiratory chain defects), and metal (hemochromatosis) and storage disorders (cystinosis). Non-autoimmune diabetes mellitus, thyroid dysfunction and/or goiter and sometimes hypoparathyroidism should steer the diagnosis towards a respiratory chain defect. Hypogonadotropic hypogonadism is frequent in haemochromatosis (often associated with diabetes), whereas primary hypogonadism is reported in Alström disease and cystinosis (both associated with diabetes, the latter also with thyroid dysfunction) and galactosemia. Hypogonadism is also frequent in X-linked adrenoleukodystrophy (with adrenal failure), congenital disorders of glycosylation, and Fabry and glycogen storage diseases (along with thyroid dysfunction in the first 3 and diabetes in the last). This is a new and growing field and is not yet very well recognized in adulthood despite its consequences on growth, bone metabolism and fertility. For this reason, physicians managing adult patients should be aware of these diagnoses.
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Affiliation(s)
- Marie-Christine Vantyghem
- Service d'Endocrinologie et Maladies Métaboliques, 1, Rue Polonovski, Hôpital C Huriez, Centre Hospitalier Régional et Universitaire de Lille, 59037 Lille cedex, France.
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Zung A, Visser TJ, Uitterlinden AG, Rivadeneira F, Friesema ECH. A child with a deletion in the monocarboxylate transporter 8 gene: 7-year follow-up and effects of thyroid hormone treatment. Eur J Endocrinol 2011; 165:823-30. [PMID: 21896621 DOI: 10.1530/eje-11-0358] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE The monocarboxylate transporter 8 (MCT8; SLC16A2) has a pivotal role in neuronal triiodothyronine (T(3)) uptake. Mutations of this transporter determine a distinct X-linked psychomotor retardation syndrome (Allan-Herndon-Dudley syndrome (AHDS)) that is attributed to disturbed thyroid hormone levels, especially elevated T(3) levels. We describe the genetic analysis of the MCT8 gene in a patient suspected for AHDS and the clinical and endocrine effects of L-thyroxine (LT(4)) or liothyronine (LT(3)) treatment intending to overcome the T(3) uptake resistance through alternative transporters. METHODS The six exons of the MCT8 gene were amplified individually by PCR. As multiple exons were missing, the length of the X-chromosomal deletion was determined by a dense SNP array, followed by PCR-based fine mapping to define the exact borders of the deleted segment. The clinical and endocrine data of the patient during 6.5 years of LT(4) treatment and two periods (3 months each) of low- and high-dose LT(3) were evaluated. RESULTS A partial deletion of the MCT8 gene (comprising five of six exons) was detected, confirming the suspected AHDS. MCT8 dysfunction was associated with partial resistance to T(3) at the hypothalamus and pituitary level, with normal responsiveness at the peripheral organs (liver and cardiovascular system). Thyroid hormone administration had no beneficial effect on the neurological status of the patient. CONCLUSION We identified a 70 kb deletion encompassing exons 2-6 of the MCT8 gene in our AHDS patient. Both LT(4) and LT(3) administration had no therapeutic effect. Alternatively, treatment of AHDS patients with thyroid hormone analogs should be considered.
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Affiliation(s)
- Amnon Zung
- Pediatric Endocrinology Unit, Kaplan Medical Center, Affiliated with the Hebrew University of Jerusalem, Rehovot 76100, Israel Department of Internal Medicine, Erasmus MC, Rotterdam, The Netherlands.
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Belcari F, Placidi G, Guzzetta A, Tonacchera M, Ciampi M, Bartoli A, Scaramuzzo RT, Frumento P, Cioni G, Pinchera A, Boldrini A, Ghirri P. Thyroid-stimulating hormone levels in the first days of life and perinatal factors associated with sub-optimal neuromotor outcome in pre-term infants. J Endocrinol Invest 2011; 34:e308-13. [PMID: 21659794 DOI: 10.3275/7795] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
AIM To identify perinatal factors associated with sub-optimal neuromotor outcome in infants without evident central nervous system lesions (intraventricular hemorrhage/ periventricular leukomalacia), with gestational age ≤30 (group I) and of 31-32 weeks (group II). PATIENTS AND METHODS A total of 102 premature infants admitted to the Neonatal Intensive Care Unit of Pisa, at 26-32 weeks of gestation, were studied. Data about perinatal factors and TSH values at 3-4 days of life were collected. The assessment of neuromotor development was performed at 18 months of corrected age, using the locomotor subscale of the Griffiths Scales of Mental Development. RESULTS Risk factors supposed to be predictive of sub-optimal neuromotor outcome (odds ratio >1) were at ≤30 weeks: male sex, small for gestational age, patent duct arterious, respiratory distress syndrome, and at 31-32 weeks: Apgar at 5 min <7, respiratory distress syndrome, patent duct arterious and birth weight <1500 g. A strong correlation was also found between TSH screening values >4,3 mU/l and suboptimal neuromotor outcome in both groups. CONCLUSIONS Several perinatal factors, acting on an immature and more vulnerable nervous system, such as the pre-term one, different for different gestational ages, are associated with a sub-optimal neuromotor outcome. Higher, but within the normal range, TSH values at screening seem to be a strong risk factor for neuromotor outcome in preterm infants without intraventricular hemorrhage or periventricular leukomalacia.
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Affiliation(s)
- F Belcari
- Division of Neonatology and Neonatal Intensive Care Unit, Department of Maternal and Child Health, S. Chiara Hospital, University of Pisa, Via Roma 35, 56100 Pisa, Italy
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Abstract
Thyroid hormone metabolism and action are largely intracellular processes that require transport of the hormone across the plasma membrane by different transporters. Two of these, MCT8 and MCT10, are close members of the monocarboxylate transporter family. MCT8 is expressed in a variety of tissues, including liver, kidney, thyroid and brain. The MCT8 gene is located on the X chromosome, and mutations in MCT8 result in severe psychomotor retardation and low serum T4 and high T3 levels in affected males. The psychomotor retardation is thought to be caused by impaired neuronal T3 uptake during brain development. The abnormal thyroid hormone levels appear to result from an increased T4 to T3 conversion in the kidney as well as altered hormone secretion from the thyroid gland. Options for therapy aim at early treatment with T3 analogues, neuronal uptake of which does not require MCT8.
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Affiliation(s)
- S Kersseboom
- Department of Internal Medicine, Erasmus MC, CA, Rotterdam, The Netherlands
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Abstract
Thyroid hormone resistance syndromes are a group of genetic conditions characterized by decreased tissue sensitivity to thyroid hormones. Three syndromes, in which resistance to hormone action is respectively due to mutations in the gene encoding for thyroid hormone receptor TRβ, impaired T4 and T3 transport, and impaired conversion of T4 to T3 mediated by deiodinases. An updated review of each of these forms of resistance is provided, and their pathogenetic mechanisms and clinical approaches are discussed.
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Affiliation(s)
- Juan Bernal
- Instituto de Investigaciones Biomédicas, CSIC-UAM y CIBER de enfermedades raras, Madrid, España.
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Menezes Filho HCD, Marui S, Manna TD, Brust ES, Radonsky V, Kuperman H, Dichtchekenian V, Setian N, Damiani D. Novel mutation in MCT8 gene in a Brazilian boy with thyroid hormone resistance and severe neurologic abnormalities. ACTA ACUST UNITED AC 2011; 55:60-6. [DOI: 10.1590/s0004-27302011000100008] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2010] [Accepted: 12/14/2010] [Indexed: 11/22/2022]
Abstract
MCT8 is a cellular transporter of thyroid hormones important in their action and metabolization. We report a male patient with the novel inactivating mutation 630insG in the coding region in exon 1 of MCT8. He was characterized clinically by severe neurologic impairment (initially with global hypotonia, later evolving with generalized hypertonia), normal growth during infancy, reduced weight gain, and absence of typical signs and symptoms of hypothyroidism, while the laboratory evaluation disclosed elevated T3, low total and free T4, and mildly elevated TSH serum levels. Treatment with levothyroxine improved thyroid hormone profile but was not able to alter the clinical picture of the patient. These data reinforce the concept that the role of MCT8 is tissue-dependent: while neurons are highly dependent on MCT8, bone tissue, adipose tissue, muscle, and liver are less dependent on MCT8 and, therefore, may suffer the consequences of the exposition to high serum T3 levels.
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