1
|
Thyroid Hormone Transporters in Pregnancy and Fetal Development. Int J Mol Sci 2022; 23:ijms232315113. [PMID: 36499435 PMCID: PMC9737226 DOI: 10.3390/ijms232315113] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 11/25/2022] [Accepted: 11/26/2022] [Indexed: 12/05/2022] Open
Abstract
Thyroid hormone is essential for fetal (brain) development. Plasma membrane transporters control the intracellular bioavailability of thyroid hormone. In the past few decades, 15 human thyroid hormone transporters have been identified, and among them, mutations in monocarboxylate transporter (MCT)8 and organic anion transporting peptide (OATP)1C1 are associated with clinical phenotypes. Different animal and human models have been employed to unravel the (patho)-physiological role of thyroid hormone transporters. However, most studies on thyroid hormone transporters focus on postnatal development. This review summarizes the research on the thyroid hormone transporters in pregnancy and fetal development, including their substrate preference, expression and tissue distribution, and physiological and pathophysiological role in thyroid homeostasis and clinical disorders. As the fetus depends on the maternal thyroid hormone supply, especially during the first half of pregnancy, the review also elaborates on thyroid hormone transport across the human placental barrier. Future studies may reveal how the different transporters contribute to thyroid hormone homeostasis in fetal tissues to properly facilitate development. Employing state-of-the-art human models will enable a better understanding of their roles in thyroid hormone homeostasis.
Collapse
|
2
|
Moran C, Schoenmakers N, Visser WE, Schoenmakers E, Agostini M, Chatterjee K. Genetic disorders of thyroid development, hormone biosynthesis and signalling. Clin Endocrinol (Oxf) 2022; 97:502-514. [PMID: 35999191 PMCID: PMC9544560 DOI: 10.1111/cen.14817] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 05/24/2022] [Accepted: 07/04/2022] [Indexed: 11/28/2022]
Abstract
Development and differentiation of the thyroid gland is directed by expression of specific transcription factors in the thyroid follicular cell which mediates hormone biosynthesis. Membrane transporters are rate-limiting for cellular entry of thyroid hormones (TH) (T4 and T3) into some tissues, with selenocysteine-containing, deiodinase enzymes (DIO1 and DIO2) converting T4 to the biologically active hormone T3. TH regulate expression of target genes via hormone-inducible nuclear receptors (TRα and TRβ) to exert their physiological effects. Primary congenital hypothyroidism (CH) due to thyroid dysgenesis may be mediated by defects in thyroid transcription factors or impaired thyroid stimulating hormone receptor function. Dyshormonogenic CH is usually due to mutations in genes mediating thyroidal iodide transport, organification or iodotyrosine synthesis and recycling. Disorders of TH signalling encompass conditions due to defects in membrane TH transporters, impaired hormone metabolism due to deficiency of deiodinases and syndromes of Resistance to thyroid hormone due to pathogenic variants in either TRα or TRβ. Here, we review the genetic basis, pathogenesis and clinical features of congenital, dysgenetic or dyshormonogenic hypothyroidism and disorders of TH transport, metabolism and action.
Collapse
Affiliation(s)
- Carla Moran
- Wellcome Trust‐MRC Institute of Metabolic ScienceUniversity of CambridgeCambridgeUK
- Present address:
Beacon Hospital and School of MedicineUniversity CollegeDublinIreland
| | - Nadia Schoenmakers
- Wellcome Trust‐MRC Institute of Metabolic ScienceUniversity of CambridgeCambridgeUK
| | - W. Edward Visser
- Department of Internal MedicineErasmus Medical Center, Academic Center for Thyroid DiseasesRotterdamThe Netherlands
| | - Erik Schoenmakers
- Wellcome Trust‐MRC Institute of Metabolic ScienceUniversity of CambridgeCambridgeUK
| | - Maura Agostini
- Wellcome Trust‐MRC Institute of Metabolic ScienceUniversity of CambridgeCambridgeUK
| | - Krishna Chatterjee
- Wellcome Trust‐MRC Institute of Metabolic ScienceUniversity of CambridgeCambridgeUK
| |
Collapse
|
3
|
Genetic and Neurological Deficiencies in the Visual System of mct8 Mutant Zebrafish. Int J Mol Sci 2022; 23:ijms23052464. [PMID: 35269606 PMCID: PMC8910067 DOI: 10.3390/ijms23052464] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/18/2022] [Accepted: 02/20/2022] [Indexed: 01/27/2023] Open
Abstract
Thyroid hormones (THs; T3 and T4) enter cells using specific transporters and regulate development and metabolism. Mutation in the TH transporter monocarboxylate transporter 8 (MCT8, SLC16A2) is associated with brain hypothyroidism and neurological impairment. We established mct8 mutant (mct8-/-) zebrafish as a model for MCT8 deficiency, which causes endocrinological, neurological, and behavioral alterations. Here, we profiled the transcriptome of mct8-/- larvae. Among hundreds of differentially expressed genes, the expression of a cluster of vision-related genes was distinct. Specifically, the expression of the opsin 1 medium wave sensitive 2 (opn1mw2) decreased in two mct8 mutants: mct8-/- and mct8-25bp-/- larvae, and under pharmacological inhibition of TH production. Optokinetic reflex (OKR) assays showed a reduction in the number of conjugated eye movements, and live imaging of genetically encoded Ca2+ indicator revealed altered neuronal activity in the pretectum area of mct8-25bp-/- larvae. These results imply that MCT8 and THs regulate the development of the visual system and suggest a mechanism to the deficiencies observed in the visual system of MCT8-deficiency patients.
Collapse
|
4
|
Wolff TM, Veil C, Dietrich JW, Müller MA. Mathematical modeling and simulation of thyroid homeostasis: Implications for the Allan-Herndon-Dudley syndrome. Front Endocrinol (Lausanne) 2022; 13:882788. [PMID: 36568087 PMCID: PMC9772020 DOI: 10.3389/fendo.2022.882788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 10/31/2022] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION A mathematical model of the pituitary-thyroid feedback loop is extended to deepen the understanding of the Allan-Herndon-Dudley syndrome (AHDS). The AHDS is characterized by unusual thyroid hormone concentrations and a mutation in the SLC16A2 gene encoding for the monocarboxylate transporter 8 (MCT8). This mutation leads to a loss of thyroid hormone transport activity. One hypothesis to explain the unusual hormone concentrations of AHDS patients is that due to the loss of thyroid hormone transport activity, thyroxine (T 4) is partially retained in thyroid cells. METHODS This hypothesis is investigated by extending a mathematical model of the pituitary-thyroid feedback loop to include a model of the net effects of membrane transporters such that the thyroid hormone transport activity can be considered. A nonlinear modeling approach based on the Michaelis-Menten kinetics and its linear approximation are employed to consider the membrane transporters. The unknown parameters are estimated through a constrained parameter optimization. RESULTS In dynamic simulations, damaged membrane transporters result in a retention of T 4 in thyroid cells and ultimately in the unusual hormone concentrations of AHDS patients. The Michaelis-Menten modeling approach and its linear approximation lead to similar results. DISCUSSION The results support the hypothesis that a partial retention of T 4 in thyroid cells represents one mechanism responsible for the unusual hormone concentrations of AHDS patients. Moreover, our results suggest that the retention of T 4 in thyroid cells could be the main reason for the unusual hormone concentrations of AHDS patients.
Collapse
Affiliation(s)
- Tobias M. Wolff
- Institute of Automatic Control, Leibniz University Hannover, Hannover, Germany
- *Correspondence: Tobias M. Wolff,
| | - Carina Veil
- Institute for System Dynamics, University of Stuttgart, Stuttgart, Germany
| | - Johannes W. Dietrich
- Diabetes, Endocrinology and Metabolism Section, Department of Internal Medicine I, St. Josef Hospital, Ruhr University Bochum, Bochum, Germany
- Diabetes Centre Bochum-Hattingen, St. Elisabeth-Hospital Blankenstein, Hattingen, Germany
- Ruhr Center for RareDiseases (CeSER), Ruhr University of Bochum and Witten/Herdecke University, Bochum, Germany
| | - Matthias A. Müller
- Institute of Automatic Control, Leibniz University Hannover, Hannover, Germany
| |
Collapse
|
5
|
Furman A, Hannoush Z, Echegoyen FB, Dumitrescu A, Refetoff S, Weiss RE. Novel DIO1 Gene Mutation Acting as Phenotype Modifier for Novel Compound Heterozygous TPO Gene Mutations Causing Congenital Hypothyroidism. Thyroid 2021; 31:1589-1591. [PMID: 34128397 PMCID: PMC8917882 DOI: 10.1089/thy.2021.0210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A family with congenital hypothyroidism was identified with two novel deleterious compound heterozygous thyroid peroxidase (TPO) mutations (c.962C>A, and c.1577C>T). Serum thyroid tests showed higher-than-expected serum-free thyroxine (T4) relative to TT3, while reverse triiodothyronine (rT3) was also elevated. Two siblings manifested a more severe phenotype of developmental delay compared with another sibling and were found to harbor an additional novel heterozygous deleterious iodothyronine deiodinase 1 (DIO1) mutation (c.395G>A). In the context of L-T4 replacement, the decreased D1 activity results in abnormal thyroid hormone metabolism with decreased triiodothyronine (T3) generation from L-T4 and may result in decreased T3 bioavailability during critical stages of development.
Collapse
Affiliation(s)
- Aryel Furman
- Department of Medicine; University of Miami Miller School of Medicine, Miami, Florida, USA
| | - Zeina Hannoush
- Department of Medicine; University of Miami Miller School of Medicine, Miami, Florida, USA
| | | | | | - Samuel Refetoff
- Department of Medicine, University of Chicago, Chicago, Illinois, USA
- Department of Genetics and University of Chicago, Chicago, Illinois, USA
- Department of Pediatrics, University of Chicago, Chicago, Illinois, USA
| | - Roy E. Weiss
- Department of Medicine; University of Miami Miller School of Medicine, Miami, Florida, USA
- Address correspondence to: Roy E. Weiss, MD, PhD, Department of Medicine, University of Miami Miller School of Medicine, 1120 NW 14th Street, Suite 310F, Miami, FL 33136-1015, USA
| |
Collapse
|
6
|
Iwayama H, Kakita H, Iwasa M, Adachi S, Takano K, Kikuchi M, Fujisawa Y, Osaka H, Yamada Y, Okumura A, Hirani K, Weiss RE, Refetoff S. Measurement of Reverse Triiodothyronine Level and the Triiodothyronine to Reverse Triiodothyronine Ratio in Dried Blood Spot Samples at Birth May Facilitate Early Detection of Monocarboxylate Transporter 8 Deficiency. Thyroid 2021; 31:1316-1321. [PMID: 34049438 PMCID: PMC8558056 DOI: 10.1089/thy.2020.0696] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Background: Monocarboxylate transporter 8 (MCT8) deficiency is an X-chromosome-linked neurodevelopmental disorder resulting from impaired thyroid hormone transport across the cell membrane. The diagnosis of MCT8 deficiency is typically delayed owing to the late appearance of signs and symptoms as well as the inability of standard biomarkers of neonatal screening to provide early detection. In this study, we report, for the first time, the ability to detect MCT8 deficiency at birth using dried blood spot (DBS) samples. Methods: We retrospectively measured triiodothyronine (T3), thyroxine (T4), and reverse T3 (rT3) levels in DBS samples obtained at 4-5 days of life from 6 infants with genetically confirmed MCT8 deficiency and from 110 controls. The latter consisted of 58 healthy term neonates obtained at the same time, 16 were stored for more than 1 year before measurement to match samples from the MCT8-deficient infants. Ten DBS samples were collected at day 1 of life and 42 samples were from prematurely born neonates. Measurements were carried out in extract from eight millimeters diameter DBS using liquid chromatography-tandem mass spectrometry. Results: Contrary to characteristic iodothyronine abnormalities of MCT8 deficiency during later life, T3 and T4 values were not discriminatory from those of other study groups. In contrast, rT3 was significantly lower. The T3/rT3 ratio was higher in the DBS samples from the MCT8-deficient infants compared with all other groups with no overlap (p < 0.0001). Conclusions: rT3 and T3/rT3 ratio in DBS samples obtained from neonates can serve as biomarkers to detect MCT8 deficiency at birth.
Collapse
Affiliation(s)
- Hideyuki Iwayama
- Department of Pediatrics, School of Medicine, Aichi Medical University, Nagakute, Japan
| | - Hiroki Kakita
- Department of Perinatal and Neonatal Medicine, School of Medicine, Aichi Medical University, Nagakute, Japan
| | - Masumi Iwasa
- Department of Pediatrics, School of Medicine, Aichi Medical University, Nagakute, Japan
| | - Shinsuke Adachi
- Department of Pediatrics, Fukuchiyama City Hospital, Kyoto, Japan
| | - Kyoko Takano
- Center for Medical Genetics, Shinshu University Hospital, Nagano, Japan
| | - Masahiro Kikuchi
- Department of Pediatrics, Hitachi General Hospital, Hitachi, Japan
| | - Yasuko Fujisawa
- Department of Pediatrics, School of Medicine, Hamamatsu University, Hamamatsu, Japan
| | - Hitoshi Osaka
- Department of Pediatrics, Jichi Medical School, Shimotsuke, Japan
| | - Yasumasa Yamada
- Department of Perinatal and Neonatal Medicine, School of Medicine, Aichi Medical University, Nagakute, Japan
| | - Akihisa Okumura
- Department of Pediatrics, School of Medicine, Aichi Medical University, Nagakute, Japan
| | - Khemraj Hirani
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Roy E. Weiss
- Department of Medicine, Miller School of Medicine, University of Miami, Miami, Florida, USA
| | - Samuel Refetoff
- Departments of Medicine, Pediatrics and Committee on Genetics, The University of Chicago, Chicago, Illinois, USA
| |
Collapse
|
7
|
Hernandez A, Martinez ME, Ng L, Forrest D. Thyroid Hormone Deiodinases: Dynamic Switches in Developmental Transitions. Endocrinology 2021; 162:bqab091. [PMID: 33963379 PMCID: PMC8248586 DOI: 10.1210/endocr/bqab091] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Indexed: 12/15/2022]
Abstract
Thyroid hormones exert pleiotropic, essential actions in mammalian, including human, development. These actions depend on provision of thyroid hormones in the circulation but also to a remarkable extent on deiodinase enzymes in target tissues that amplify or deplete the local concentration of the primary active form of the hormone T3 (3,5,3'-triiodothyronine), the high affinity ligand for thyroid hormone receptors. Genetic analyses in mice have revealed key roles for activating (DIO2) and inactivating (DIO3) deiodinases in cell differentiation fates and tissue maturation, ultimately promoting neonatal viability, growth, fertility, brain development, and behavior, as well as metabolic, endocrine, and sensory functions. An emerging paradigm is how the opposing activities of DIO2 and DIO3 are coordinated, providing a dynamic switch that controls the developmental timing of a tissue response, often during neonatal and maturational transitions. A second paradigm is how cell to cell communication within a tissue determines the response to T3. Deiodinases in specific cell types, often strategically located near to blood vessels that convey thyroid hormones into the tissue, can regulate neighboring cell types, suggesting a paracrine-like layer of control of T3 action. We discuss deiodinases as switches for developmental transitions and their potential to influence tissue dysfunction in human thyroid disorders.
Collapse
Affiliation(s)
- Arturo Hernandez
- Department of Molecular Medicine, Maine Medical Center Research Institute, Maine Health, Scarborough, Maine 04074, USA
- Department of Medicine, Tufts University School of Medicine, Boston, Massachusetts 02111, USA
- Graduate School of Biomedical Science and Engineering, University of Maine, Orono, Maine 04469, USA
| | - M Elena Martinez
- Department of Molecular Medicine, Maine Medical Center Research Institute, Maine Health, Scarborough, Maine 04074, USA
| | - Lily Ng
- National Institute of Diabetes and Digestive and Kidney Diseases, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Douglas Forrest
- National Institute of Diabetes and Digestive and Kidney Diseases, Laboratory of Endocrinology and Receptor Biology, National Institutes of Health, Bethesda, Maryland 20892, USA
| |
Collapse
|
8
|
Morte B, Gil-Ibañez P, Heuer H, Bernal J. Brain Gene Expression in Systemic Hypothyroidism and Mouse Models of MCT8 Deficiency: The Mct8-Oatp1c1-Dio2 Triad. Thyroid 2021; 31:985-993. [PMID: 33307956 DOI: 10.1089/thy.2020.0649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Background: The monocarboxylate transporter 8 (Mct8) protein is a primary thyroxine (T4) and triiodothyronine (T3) (thyroid hormone [TH]) transporter. Mutations of the MCT8-encoding, SLC16A2 gene alter thyroid function and TH metabolism and severely impair neurodevelopment (Allan-Herndon-Dudley syndrome [AHDS]). Mct8-deficient mice manifest thyroid alterations but lack neurological signs. It is believed that Mct8 deficiency in mice is compensated by T4 transport through the Slco1c1-encoded organic anion transporter polypeptide 1c1 (Oatp1c1). This allows local brain generation of sufficient T3 by the Dio2-encoded type 2 deiodinase, thus preventing brain hypothyroidism. The Slc16a2/Slco1c1 (MO) and Slc16a2/Dio2 (MD) double knockout (KO) mice lacking T4 and T3 transport, or T3 transport and T4 deiodination, respectively, should be appropriate models of AHDS. Our goal was to compare the cerebral hypothyroidism of systemic hypothyroidism (SH) caused by thyroid gland blockade with that present in the double KO mice. Methods: We performed RNA sequencing by using RNA from the cerebral cortex and striatum of SH mice and the double KO mice on postnatal days 21-23. Real-time polymerase chain reaction was used to confirm RNA-Seq results in replicate biological samples. Cell type involvement was assessed from cell type-enriched genes. Functional genomic differences were analyzed by functional node activity based on a probabilistic graphical model. Results: Each of the three conditions gave a different pattern of gene expression, with partial overlaps. SH gave a wider and highest variation of gene expression than MD or MO. This was partially due to secondary gene responses to hypothyroidism. The set of primary transcriptional T3 targets showed a tighter overlap, but quantitative gene responses indicated that the gene responses in SH were more severe than in MD or MO. Examination of cell type-enriched genes indicated cellular differences between the three conditions. Conclusions: The results indicate that the neurological impairment of AHDS is too severe to be fully explained by TH deprivation only.
Collapse
Affiliation(s)
- Beatriz Morte
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Center for Biomedical Research on Rare Diseases (Ciberer U708), Madrid, Spain
| | - Pilar Gil-Ibañez
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Center for Biomedical Research on Rare Diseases (Ciberer U708), Madrid, Spain
| | - Heike Heuer
- Department of Endocrinology, Diabetes and Metabolism, University of Duisburg-Essen, Essen, Germany
| | - Juan Bernal
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas, Universidad Autónoma de Madrid, Center for Biomedical Research on Rare Diseases (Ciberer U708), Madrid, Spain
| |
Collapse
|
9
|
França MM, German A, Fernandes GW, Liao XH, Bianco AC, Refetoff S, Dumitrescu AM. Human Type 1 Iodothyronine Deiodinase ( DIO1) Mutations Cause Abnormal Thyroid Hormone Metabolism. Thyroid 2021; 31:202-207. [PMID: 32718224 PMCID: PMC7891200 DOI: 10.1089/thy.2020.0253] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Background: Iodothyronine deiodinase-1 (D1) selenoenzyme regulates the systemic supply of active thyroid hormone (TH). Transient decrease in D1 enzymatic activity is clinically relevant and adaptive in nonthyroidal illness such as fasting or acute illness. However, DIO1 gene defects have not been reported in humans. Methods: Genetic analysis was performed using whole-exome sequencing in members of two unrelated families presenting with abnormal serum thyroid function tests. Plasmid constructs containing the two pathogenic DIO1 variants were used for in vitro studies assessing the kinetics of their enzymatic activity. Thyroid function tests were measured in Dio1 heterozygous-null mice. Results: We report the novel identification and characterization of two missense DIO1 pathogenic variants (resulting in p.Asn94Lys and p.Met201Ile) in two unrelated families presenting with abnormal TH metabolism with elevated serum reverse triiodothyronine (rT3) levels and rT3/T3 ratios. These characteristic in vivo parameters are also present in Dio1 heterozygous-null mice. Kinetic studies of the resulting mutant D1 proteins demonstrate two- to threefold higher Km indicating lower substrate affinity and slower enzyme velocity. Conclusions: We report the identification and characterization of two missense DIO1 pathogenic variants identified in families with abnormal TH metabolism. This is the first demonstration of inherited D1 deficiency in humans.
Collapse
Affiliation(s)
- Monica M. França
- Section of Endocrinology Diabetes and Metabolism, Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Alina German
- Department of Pediatric Endocrine Unit, Bnei Zion Medical Center, Clalit Health Service and Technion-the Israel Institute of Technology, Haifa, Israel
| | - Gustavo W. Fernandes
- Section of Endocrinology Diabetes and Metabolism, Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Xiao-Hui Liao
- Section of Endocrinology Diabetes and Metabolism, Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Antonio C. Bianco
- Section of Endocrinology Diabetes and Metabolism, Department of Medicine, The University of Chicago, Chicago, Illinois, USA
| | - Samuel Refetoff
- Section of Endocrinology Diabetes and Metabolism, Department of Medicine, The University of Chicago, Chicago, Illinois, USA
- Department of Pediatrics and Committees, The University of Chicago, Chicago, Illinois, USA
- Genetics, The University of Chicago, Chicago, Illinois, USA
| | - Alexandra M. Dumitrescu
- Section of Endocrinology Diabetes and Metabolism, Department of Medicine, The University of Chicago, Chicago, Illinois, USA
- Molecular Metabolism and Nutrition, The University of Chicago, Chicago, Illinois, USA
| |
Collapse
|
10
|
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] [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.
Collapse
|
11
|
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] [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.
Collapse
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:
| |
Collapse
|
12
|
Groeneweg S, van Geest FS, Peeters RP, Heuer H, Visser WE. Thyroid Hormone Transporters. Endocr Rev 2020; 41:5637505. [PMID: 31754699 DOI: 10.1210/endrev/bnz008] [Citation(s) in RCA: 86] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Accepted: 11/07/2019] [Indexed: 02/08/2023]
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).
Collapse
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
| |
Collapse
|
13
|
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] [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.
Collapse
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
| |
Collapse
|
14
|
Bárez-López S, Grijota-Martínez C, Ausó E, Fernández-de Frutos M, Montero-Pedrazuela A, Guadaño-Ferraz A. Adult Mice Lacking Mct8 and Dio2 Proteins Present Alterations in Peripheral Thyroid Hormone Levels and Severe Brain and Motor Skill Impairments. Thyroid 2019; 29:1669-1682. [PMID: 31359845 DOI: 10.1089/thy.2019.0068] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Background: Mutations in the thyroid hormone (TH) transporter monocarboxylate transporter 8 (MCT8) lead to peripheral hyperthyroidism and profound psychomotor alterations in humans. Mice lacking Mct8 present peripheral hyperthyroidism but no gross neurological abnormalities due to brain compensatory mechanisms involving the enzyme deiodinase type 2 (Dio2). Methods: Here we have analyzed the endocrine and neurologic phenotype of mice lacking both Mct8 and Dio2 at three and six months of age. Thyroxine (T4) and 3,5,3' triiodothyronine (T3) levels/content were measured by specific radioimmunoassays; motor skill performance was evaluated by the footprint, rotarod, four limb hanging wire, and balance beam tests; and brain histological analysis was performed by immunostaining for neurofilament and parvalbumin. Results: We have found that this mouse model presents peripheral hyperthyroidism and brain hypothyroidism. Interestingly, the severity of the brain hypothyroidism seems permanent and varies across regions, with the striatum being a particularly affected area. We have also found brain alterations at the histological level compatible with TH deficiency and impaired motor skills. Conclusions: These findings indicate the potential of Mct8/Dio2-deficient mice to represent a model for human MCT8 deficiency, to understand the mechanisms underlying its pathophysiology, and ultimately design therapeutic interventions for human patients.
Collapse
Affiliation(s)
- Soledad Bárez-López
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Unit 708, Center for Biomedical Research On Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
| | - Carmen Grijota-Martínez
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Unit 708, Center for Biomedical Research On Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
| | - 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, Alicante, Spain
| | - Mario Fernández-de Frutos
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Ana Montero-Pedrazuela
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
| | - Ana Guadaño-Ferraz
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas (CSIC)-Universidad Autónoma de Madrid (UAM), Madrid, Spain
- Unit 708, Center for Biomedical Research On Rare Diseases (Ciberer), Instituto de Salud Carlos III, Madrid, Spain
| |
Collapse
|
15
|
Kim S, Cho YH, Won S, Ku JL, Moon HB, Park J, Choi G, Kim S, Choi K. Maternal exposures to persistent organic pollutants are associated with DNA methylation of thyroid hormone-related genes in placenta differently by infant sex. ENVIRONMENT INTERNATIONAL 2019; 130:104956. [PMID: 31272017 DOI: 10.1016/j.envint.2019.104956] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 06/21/2019] [Accepted: 06/21/2019] [Indexed: 06/09/2023]
Abstract
Exposure to persistent organic pollutants (POPs) during pregnancy is associated with a disruption in thyroid hormone balance. The placenta serves as an important environment for fetal development and also regulates thyroid hormone supply to the fetus. However, epigenetic changes of thyroid regulating genes in placenta have rarely been studied. This study was conducted to evaluate the association between several POP concentrations in maternal serum and DNA methylation of thyroid hormone-related genes in the placenta. The placenta samples were collected from 106 Korean mother at delivery, and the promoter methylation of the placental genes was measured by a bisulfite pyrosequencing. The deiodinase type 3 (DIO3), monocarboxylate transporter 8 (MCT8), and transthyretin (TTR) genes were selected as the target genes as they play an important role in the regulation of fetal thyroid balance. Because people are exposed to multiple chemicals at the same time, a multiple-POP model using principal component analysis (PCA) was applied to evaluate the association between the multiple POPs exposure and the epigenetic change in placenta. In addition, a single-POP model which includes one chemical each in the statistical model for association was conducted. Based on the single-POP models, serum concentrations of p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and brominated diphenyl ether-47 (BDE-47) were significantly associated with an increase in placental DIO3 methylation, but only among female infants. Among male infants, a positive association between serum p,p'-DDT and MCT8 methylation level was found. According to the multiple-POP models, serum DDTs were positively associated with DIO3 methylation in the placenta of female infants, while a positive association with MCT8 methylation was observed in those of the male infants. Our observation showed that in utero exposure to DDTs may influence the DNA methylation of DIO3 and MCT8 genes in the placenta, in a sexually dimorphic manner. These alterations in placental epigenetic regulation may in part explain the thyroid hormone disruption observed among the newborns or infants followed by in utero exposure to POPs.
Collapse
Affiliation(s)
- Sujin Kim
- Graduate School of Public Health, Seoul National University, Seoul 08826, Republic of Korea; Institute of Environmental Technology, Department of Environmental Engineering, Seoul National University of Science & Technology, Seoul 01811, Republic of Korea
| | - Yoon Hee Cho
- Center for Environmental Health Sciences, Biomedical and Pharmaceutical Sciences, College of Health Professions and Biomedical Sciences, University of Montana, Missoula, MT, 59812, USA
| | - Sungho Won
- Graduate School of Public Health, Seoul National University, Seoul 08826, Republic of Korea
| | - Ja-Lok Ku
- Laboratory of Cell Biology, Cancer Research Institute, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea; Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, 03080, Republic of Korea
| | - Hyo-Bang Moon
- Department of Marine Science and Convergence Engineering, Hanyang University, Ansan, 15588, Republic of Korea
| | - Jeongim Park
- College of Natural Sciences, Soonchunhyang University, Asan 31538, Republic of Korea
| | - Gyuyeon Choi
- Department of Obstetrics and Gynecology, College of Medicine, Soonchunhyang University Hospital, Seoul, 04401, Republic of Korea
| | - Sungkyoon Kim
- Graduate School of Public Health, Seoul National University, Seoul 08826, Republic of Korea
| | - Kyungho Choi
- Graduate School of Public Health, Seoul National University, Seoul 08826, Republic of Korea.
| |
Collapse
|
16
|
Bárez-López S, Hartley MD, Grijota-Martínez C, Scanlan TS, Guadaño-Ferraz A. Sobetirome and its Amide Prodrug Sob-AM2 Exert Thyromimetic Actions in Mct8-Deficient Brain. Thyroid 2018; 28:1211-1220. [PMID: 29845892 PMCID: PMC6154442 DOI: 10.1089/thy.2018.0008] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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.
Collapse
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
| |
Collapse
|
17
|
Qin SL, He Q, Hu L, He CY, Gao LC, Young CA, Chen J, Jiang CF, Luo XF, Zhou Y, Sheng X, Li ZH, Chen ML, Xu G. The relationship between inflammatory factors, oxidative stress and DIO-1 concentration in patients with chronic renal failure accompanied with or without euthyroid sick syndrome. J Int Med Res 2018; 46:4061-4070. [PMID: 30152254 PMCID: PMC6166338 DOI: 10.1177/0300060518778190] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Objective To investigate the relationship between inflammatory factors, oxidative
stress and type 1 deiodinase (DIO-1) concentration in patients with chronic
renal failure (CRF) with or without euthyroid sick syndrome (ESS). Methods This study recruited patients with CRF and divided them into two groups:
group 1 had low free triiodothyronine (FT3) levels; and group 2 had normal
FT3 levels. Group 3 consisted of healthy volunteers. Serum levels of
interleukin (IL)-6, IL-1β, tumour necrosis factor (TNF)-α, 8-isoprostane and
DIO-1 were measured using enzyme-linked immunosorbent assays. Multiple
regression analysis was used to analyse correlations between parameters. Results Sixty patients were enrolled into each group and the groups were comparable
in terms of vital signs, white blood cell count, free thyroxine and thyroid
stimulating hormone concentrations. The serum DIO-1 concentration was
significantly higher in group 2 than in groups 1 and 3. Multivariate
regression analysis revealed that the DIO-1 concentration was inversely
correlated with the TNF-α concentration. Conclusions Patients with CRF without ESS showed higher concentrations of DIO-1 than
patients with ESS. The DIO-1 concentration was inversely correlated with the
TNF-α concentration, which might indicate that the inflammatory response was
milder in the patients with CRF without ESS than in those with ESS.
Collapse
Affiliation(s)
- Shu-Lan Qin
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Qi He
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Ling Hu
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Chun-Yan He
- 3 Department of Experimental Centre, Jiangxi Health Vocational College, Nanchang, Jiangxi Province, China
| | - Li-Cheng Gao
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | | | - Juan Chen
- 3 Department of Experimental Centre, Jiangxi Health Vocational College, Nanchang, Jiangxi Province, China
| | - Cheng-Fang Jiang
- 3 Department of Experimental Centre, Jiangxi Health Vocational College, Nanchang, Jiangxi Province, China
| | - Xiang-Feng Luo
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Ying Zhou
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Xia Sheng
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Zhi-Hong Li
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Mei-Ling Chen
- 1 Department of Endocrinology, Third Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| | - Gaosi Xu
- 2 Department of Nephrology, Second Affiliated Hospital, Nanchang University, Nanchang, Jiangxi Province, China
| |
Collapse
|
18
|
|
19
|
Gouveia CHA, Miranda-Rodrigues M, Martins GM, Neofiti-Papi B. Thyroid Hormone and Skeletal Development. VITAMINS AND HORMONES 2018; 106:383-472. [PMID: 29407443 DOI: 10.1016/bs.vh.2017.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Thyroid hormone (TH) is essential for skeletal development from the late fetal life to the onset of puberty. During this large window of actions, TH has key roles in endochondral and intramembranous ossifications and in the longitudinal bone growth. There is evidence that TH acts directly in skeletal cells but also indirectly, specially via the growth hormone/insulin-like growth factor-1 axis, to control the linear skeletal growth and maturation. The presence of receptors, plasma membrane transporters, and activating and inactivating enzymes of TH in skeletal cells suggests that direct actions of TH in these cells are crucial for skeletal development, which has been confirmed by several in vitro and in vivo studies, including mouse genetic studies, and clinical studies in patients with resistance to thyroid hormone due to dominant-negative mutations in TH receptors. This review examines progress made on understanding the mechanisms by which TH regulates the skeletal development.
Collapse
Affiliation(s)
- Cecilia H A Gouveia
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; Experimental Pathophysiology Program, School of Medicine, University of São Paulo, São Paulo, SP, Brazil.
| | | | - Gisele M Martins
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; Experimental Pathophysiology Program, School of Medicine, University of São Paulo, São Paulo, SP, Brazil; Federal University of Espírito Santo, Vitória, ES, Brazil
| | - Bianca Neofiti-Papi
- Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil; Experimental Pathophysiology Program, School of Medicine, University of São Paulo, São Paulo, SP, Brazil
| |
Collapse
|
20
|
Richard S, Flamant F. Regulation of T3 Availability in the Developing Brain: The Mouse Genetics Contribution. Front Endocrinol (Lausanne) 2018; 9:265. [PMID: 29892264 PMCID: PMC5985302 DOI: 10.3389/fendo.2018.00265] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Accepted: 05/07/2018] [Indexed: 12/11/2022] Open
Abstract
Alterations in maternal thyroid physiology may have deleterious consequences on the development of the fetal brain, but the underlying mechanisms remain elusive, hampering the development of appropriate therapeutic strategies. The present review sums up the contribution of genetically modified mouse models to this field. In particular, knocking out genes involved in thyroid hormone (TH) deiodination, transport, and storage has significantly improved the picture that we have of the economy of TH in the fetal brain and the underlying genetic program. These data pave the way for future studies to bridge the gap in knowledge between thyroid physiology and brain development.
Collapse
|
21
|
Thyroid Hormone Signaling in the Development of the Endochondral Skeleton. VITAMINS AND HORMONES 2018; 106:351-381. [PMID: 29407442 PMCID: PMC9830754 DOI: 10.1016/bs.vh.2017.06.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Thyroid hormone (TH) is an established regulator of skeletal growth and maintenance both in clinical studies and in laboratory models. The clinical consequences of altered thyroid status on the skeleton during development and in adulthood are well known, and genetic mouse models in which elements of the TH signaling axis have been manipulated illuminate the mechanisms which underlie TH regulation of the skeleton. TH is involved in the regulation of the balance between proliferation and differentiation in several skeletal cell types including chondrocytes, osteoblasts, and osteoclasts. The effects of TH are mediated primarily via the thyroid hormone receptors (TRs) α and β, ligand-inducible nuclear receptors which act as transcription factors to regulate target gene expression. Both TRα and TRβ signaling are important for different stages of skeletal development. The molecular mechanisms of TH action in bone are complex and include interaction with a number of growth factor signaling pathways. This review provides an overview of the regulation and mechanisms of TH action in bone, focusing particularly on the role of TH in endochondral bone formation during postnatal growth.
Collapse
|
22
|
Leitch VD, Di Cosmo C, Liao XH, O’Boy S, Galliford TM, Evans H, Croucher PI, Boyde A, Dumitrescu A, Weiss RE, Refetoff S, Williams GR, Bassett JHD. An Essential Physiological Role for MCT8 in Bone in Male Mice. Endocrinology 2017; 158:3055-3066. [PMID: 28637283 PMCID: PMC5659673 DOI: 10.1210/en.2017-00399] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Accepted: 06/12/2017] [Indexed: 11/19/2022]
Abstract
T3 is an important regulator of skeletal development and adult bone maintenance. Thyroid hormone action requires efficient transport of T4 and T3 into target cells. We hypothesized that monocarboxylate transporter (MCT) 8, encoded by Mct8 on the X-chromosome, is an essential thyroid hormone transporter in bone. To test this hypothesis, we determined the juvenile and adult skeletal phenotypes of male Mct8 knockout mice (Mct8KO) and Mct8D1D2KO compound mutants, which additionally lack the ability to convert the prohormone T4 to the active hormone T3. Prenatal skeletal development was normal in both Mct8KO and Mct8D1D2KO mice, whereas postnatal endochondral ossification and linear growth were delayed in both Mct8KO and Mct8D1D2KO mice. Furthermore, bone mass and mineralization were decreased in adult Mct8KO and Mct8D1D2KO mice, and compound mutants also had reduced bone strength. Delayed bone development and maturation in Mct8KO and Mct8D1D2KO mice is consistent with decreased thyroid hormone action in growth plate chondrocytes despite elevated serum T3 concentrations, whereas low bone mass and osteoporosis reflects increased thyroid hormone action in adult bone due to elevated systemic T3 levels. These studies identify an essential physiological requirement for MCT8 in chondrocytes, and demonstrate a role for additional transporters in other skeletal cells during adult bone maintenance.
Collapse
Affiliation(s)
- Victoria D. Leitch
- Molecular Endocrinology Laboratory, Department of Medicine, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| | - Caterina Di Cosmo
- Department of Medicine, The University of Chicago, Chicago, Illinois 60637
| | - Xiao-Hui Liao
- Department of Medicine, The University of Chicago, Chicago, Illinois 60637
| | - Sam O’Boy
- Molecular Endocrinology Laboratory, Department of Medicine, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| | - Thomas M. Galliford
- Molecular Endocrinology Laboratory, Department of Medicine, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| | - Holly Evans
- Sheffield Myeloma Research Team, University of Sheffield, Sheffield S10 2RX, United Kingdom
| | - Peter I. Croucher
- The Garvan Institute of Medical Research and St. Vincent’s Clinical School, University of New South Wales Medicine, Sydney, New South Wales 2010, Australia
| | - Alan Boyde
- Queen Mary University of London, Oral Growth and Development, Bart’s and The London School of Medicine and Dentistry, London E1 4NS, United Kingdom
| | | | - Roy E. Weiss
- Department of Medicine, University of Miami, Miami, Florida 33136
| | - Samuel Refetoff
- Department of Medicine, The University of Chicago, Chicago, Illinois 60637
- Department of Pediatrics, The University of Chicago, Chicago, Illinois 60637
- Committee on Genetics, The University of Chicago, Chicago, Illinois 60637
| | - Graham R. Williams
- Molecular Endocrinology Laboratory, Department of Medicine, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| | - J. H. Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Medicine, Hammersmith Campus, Imperial College London, London W12 0NN, United Kingdom
| |
Collapse
|
23
|
Citrus flavanones mildly interfere with pituitary-thyroid axis in old-aged male rats. Acta Histochem 2017; 119:292-301. [PMID: 28262328 DOI: 10.1016/j.acthis.2017.02.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2016] [Revised: 02/21/2017] [Accepted: 02/21/2017] [Indexed: 11/21/2022]
Abstract
Citrus flavanones naringenin (NAR) and hesperetin (HES) are potent antioxidants that may contribute to maintenance of health at old age by improving cardiovascular and metabolic status. However, they may also affect thyroid hormone economy. Keeping in mind impaired thyroid function at older age, in this study we tested wheather NAR or HES administration potentiate this decline. NAR or HES were administrated orally (15mg/kg) to male 24-month-old Wistar rats during 4 weeks. Control groups received vehicle, sunflower oil. Qualitative and quantitative immunohistochemical and immunofluorescent expression of specific proteins and stereological analyses of thyroid tissue were performed. Thyroid stimulating hormone (TSH) and total thyroxine (T4) concentrations were measured in serum. Thyroid parenchyma of both flavanone-treated groups was characterized by lower (p<0.05) absolute and relative volume of luminal colloid, accompanied by elevated (p<0.05) relative volume of stroma in comparison with the controls. No hypertrophy or absolute thyroid volume change was detected. Intensity of immunopositive signal for thyroglobulin (Tg) and T4 bound to Tg (T4-Tg) increased (p<0.05) in the colloid of thyroid follicles after both flavanone treatments. Serum TSH increased (p<0.05) after NAR, while T4 remained unchanged after both treatments. In conclusion, NAR elevated serum TSH in old-aged males, thus being more potent than HES in altering pituitary-thyroid axis. However, changes in thyroid structure, namely moderate colloid depletion and higher Tg and T4-Tg protein expressions after both treatments, indicate preserved capacity of the gland to compensate flavanone interfering, and maintain T4 production in old-aged males.
Collapse
|
24
|
Weber J, McInnes J, Kizilirmak C, Rehders M, Qatato M, Wirth EK, Schweizer U, Verrey F, Heuer H, Brix K. Interdependence of thyroglobulin processing and thyroid hormone export in the mouse thyroid gland. Eur J Cell Biol 2017; 96:440-456. [PMID: 28274595 DOI: 10.1016/j.ejcb.2017.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/08/2017] [Accepted: 02/09/2017] [Indexed: 02/08/2023] Open
Abstract
Thyroid hormone (TH) target cells need to adopt mechanisms to maintain sufficient levels of TH to ensure regular functions. This includes thyroid epithelial cells, which generate TH in addition to being TH-responsive. However, the cellular and molecular pathways underlying thyroid auto-regulation are insufficiently understood. In order to investigate whether thyroglobulin processing and TH export are sensed by thyrocytes, we inactivated thyroglobulin-processing cathepsins and TH-exporting monocarboxylate transporters (Mct) in the mouse. The states of thyroglobulin storage and its protease-mediated processing and degradation were related to the levels of TH transporter molecules by immunoblotting and immunofluorescence microscopy. Thyroid epithelial cells of cathepsin-deficient mice showed increased Mct8 protein levels at the basolateral plasma membrane domains when compared to wild type controls. While the protein amounts of the thyroglobulin-degrading cathepsin D remained largely unaffected by Mct8 or Mct10 single-deficiencies, a significant increase in the amounts of the thyroglobulin-processing cathepsins B and L was detectable in particular in Mct8/Mct10 double deficiency. In addition, it was observed that larger endo-lysosomes containing cathepsins B, D, and L were typical for Mct8- and/or Mct10-deficient mouse thyroid epithelial cells. These data support the notion of a crosstalk between TH transporters and thyroglobulin-processing proteases in thyroid epithelial cells. We conclude that a defect in exporting thyroxine from thyroid follicles feeds back positively on its cathepsin-mediated proteolytic liberation from the precursor thyroglobulin, thereby adding to the development of auto-thyrotoxic states in Mct8 and/or Mct10 deficiencies. The data suggest TH sensing molecules within thyrocytes that contribute to thyroid auto-regulation.
Collapse
Affiliation(s)
- Jonas Weber
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Joseph McInnes
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Cise Kizilirmak
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Maren Rehders
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Maria Qatato
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany
| | - Eva K Wirth
- Charité-Universitätsmedizin Berlin, Institut für Experimentelle Endokrinologie, Augustenburger Platz 1, D-13353 Berlin, Germany
| | - Ulrich Schweizer
- Universität Bonn, Institut für Biochemie und Molekularbiologie, Nußallee 11, D-53115 Bonn, Germany
| | - Francois Verrey
- Universität Zürich, Physiologisches Institut, Winterthurerstrasse 190, CH-8057 Zürich, Switzerland
| | - Heike Heuer
- IUF - Leibniz Institut für umweltmedizinische Forschung, Auf'm Hennekamp 50, D-40225 Düsseldorf, Germany
| | - Klaudia Brix
- Jacobs University Bremen, Department of Life Sciences and Chemistry, Campus Ring 1, D-28759 Bremen, Germany.
| |
Collapse
|
25
|
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.
Collapse
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.
| |
Collapse
|
26
|
Abstract
Thyroid hormones (TH) are endocrine messengers essential for normal development and function of virtually every vertebrate. The hypothalamic-pituitary-thyroid axis is exquisitely modulated to maintain nearly constant TH (T4 and T3) levels in circulation. However peripheral tissues and the CNS control the intracellular availability of TH, suggesting that circulating concentrations of TH are not fully representative of what each cell type sees. Indeed, recent work in the field has identified that TH transporters, deiodinases and thyroid hormone receptor coregulators can strongly control tissue-specific sensitivity to a set amount of TH. Furthermore, the mechanism by which the thyroid hormone receptors regulate target gene expression can vary by gene, tissue and cellular context. This review will highlight novel insights into the machinery that controls the cellular response to TH, which include unique signaling cascades. These findings shed new light into the pathophysiology of human diseases caused by abnormal TH signaling.
Collapse
Affiliation(s)
- Arturo Mendoza
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Anthony N Hollenberg
- Division of Endocrinology, Diabetes and Metabolism, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
27
|
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] [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.
Collapse
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
| |
Collapse
|
28
|
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] [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.
Collapse
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
| |
Collapse
|
29
|
Abstract
The skeleton is an exquisitely sensitive and archetypal T3-target tissue that demonstrates the critical role for thyroid hormones during development, linear growth, and adult bone turnover and maintenance. Thyrotoxicosis is an established cause of secondary osteoporosis, and abnormal thyroid hormone signaling has recently been identified as a novel risk factor for osteoarthritis. Skeletal phenotypes in genetically modified mice have faithfully reproduced genetic disorders in humans, revealing the complex physiological relationship between centrally regulated thyroid status and the peripheral actions of thyroid hormones. Studies in mutant mice also established the paradigm that T3 exerts anabolic actions during growth and catabolic effects on adult bone. Thus, the skeleton represents an ideal physiological system in which to characterize thyroid hormone transport, metabolism, and action during development and adulthood and in response to injury. Future analysis of T3 action in individual skeletal cell lineages will provide new insights into cell-specific molecular mechanisms and may ultimately identify novel therapeutic targets for chronic degenerative diseases such as osteoporosis and osteoarthritis. This review provides a comprehensive analysis of the current state of the art.
Collapse
Affiliation(s)
- J H Duncan Bassett
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, Hammersmith Campus, London W12 0NN, United Kingdom
| | - Graham R Williams
- Molecular Endocrinology Laboratory, Department of Medicine, Imperial College London, Hammersmith Campus, London W12 0NN, United Kingdom
| |
Collapse
|
30
|
Donzelli R, Colligiani D, Kusmic C, Sabatini M, Lorenzini L, Accorroni A, Nannipieri M, Saba A, Iervasi G, Zucchi R. Effect of Hypothyroidism and Hyperthyroidism on Tissue Thyroid Hormone Concentrations in Rat. Eur Thyroid J 2016; 5:27-34. [PMID: 27099836 PMCID: PMC4836127 DOI: 10.1159/000443523] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 12/17/2015] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND OBJECTIVE The present study was aimed at determining the effects of experimental hypothyroidism and hyperthyroidism on tissue thyroid hormones by a mass spectrometry-based technique. METHODS Rats were subjected to propylthiouracil treatment or administration of exogenous triiodothyronine (T3) or thyroxine (T4). Tissue T3 and T4 were measured by liquid chromatography tandem mass spectrometry in the heart, liver, kidney, visceral and subcutaneous adipose tissue, and brain. RESULTS Baseline tissue T3 and T4 concentrations ranged from 0.2 to 20 pmol ∙ g(-1) and from 3 to 125 pmol ∙ g(-1), respectively, with the highest values in the liver and kidney, and the lowest values in the adipose tissue. The T3/T4 ratio (expressed as a percentage) was in the 7-20% range in all tissues except the brain, where it averaged 75%. In hypothyroidism, tissue T3 was more severely reduced than serum free T3, averaging 1-6% of the baseline versus 30% of the baseline. The extent of tissue T3 reduction, expressed as percentage of the baseline, was not homogeneous (p < 0.001), with liver = kidney > brain > heart > adipose tissue. The tissue T3/T4 ratio significantly increased in all organs except the kidney, averaging 330% in the brain and 50-90% in the other tissues. By contrast, exogenous T3 and T4 administration produced similar increases in serum free T3 and in tissue T3, and the relative changes were not significantly different between different tissues. CONCLUSIONS While the response to increased thyroid hormones availability was similar in all tissues, decreased thyroid hormone availability induced compensatory responses, leading to a significant mismatch between changes in serum and in specific tissues.
Collapse
Affiliation(s)
| | - Daria Colligiani
- Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | | | | | | | - Alice Accorroni
- Departments of Pathology, University of Pisa, Pisa, Italy
- Scuola Superiore Sant'Anna, Pisa, Italy
| | | | | | | | - Riccardo Zucchi
- Departments of Pathology, University of Pisa, Pisa, Italy
- *Riccardo Zucchi, MD, PhD, Laboratory of Biochemistry, Department of Pathology, University of Pisa, via Roma 55, IT-56126 Pisa (Italy), E-Mail
| |
Collapse
|
31
|
Ferrara AM, Liao XH, Ye H, Weiss RE, Dumitrescu AM, Refetoff S. The Thyroid Hormone Analog DITPA Ameliorates Metabolic Parameters of Male Mice With Mct8 Deficiency. Endocrinology 2015; 156:3889-94. [PMID: 26322373 PMCID: PMC4606752 DOI: 10.1210/en.2015-1234] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Mutations in the gene encoding the thyroid hormone (TH) transporter, monocarboxylate transporter 8 (MCT8), cause mental retardation in humans associated with a specific thyroid hormone phenotype manifesting high serum T3 and low T4 and rT3 levels. Moreover, these patients have failure to thrive, and physiological changes compatible with thyrotoxicosis. Recent studies in Mct8-deficient (Mct8KO) mice revealed that the high serum T3 causes increased energy expenditure. The TH analog, diiodothyropropionic acid (DITPA), enters cells independently of Mct8 transport and shows thyromimetic action but with a lower metabolic activity than TH. In this study DITPA was given daily ip to adult Mct8KO mice to determine its effect on thyroid tests in serum and metabolism (total energy expenditure, respiratory exchange rate, and food and water intake). In addition, we measured the expression of TH-responsive genes in the brain, liver, and muscles to assess the thyromimetic effects of DITPA. Administration of 0.3 mg DITPA per 100 g body weight to Mct8KO mice brought serum T3 levels and the metabolic parameters studied to levels observed in untreated Wt animals. Analysis of TH target genes revealed amelioration of the thyrotoxic state in liver, somewhat in the soleus, but there was no amelioration of the brain hypothyroidism. In conclusion, at the dose used, DITPA mainly ameliorated the hypermetabolism of Mct8KO mice. This thyroid hormone analog is suitable for the treatment of the hypermetabolism in patients with MCT8 deficiency, as suggested in limited preliminary human trials.
Collapse
Affiliation(s)
- Alfonso Massimiliano Ferrara
- Departments of Medicine (A.M.F., X.-H.L., H.Y., 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
| | - Xiao-Hui Liao
- Departments of Medicine (A.M.F., X.-H.L., H.Y., 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
| | - Honggang Ye
- Departments of Medicine (A.M.F., X.-H.L., H.Y., 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
| | - Roy E Weiss
- Departments of Medicine (A.M.F., X.-H.L., H.Y., 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
| | - Alexandra M Dumitrescu
- Departments of Medicine (A.M.F., X.-H.L., H.Y., 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
| | - Samuel Refetoff
- Departments of Medicine (A.M.F., X.-H.L., H.Y., 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
| |
Collapse
|
32
|
Gereben B, McAninch EA, Ribeiro MO, Bianco AC. Scope and limitations of iodothyronine deiodinases in hypothyroidism. Nat Rev Endocrinol 2015; 11:642-652. [PMID: 26416219 PMCID: PMC5003781 DOI: 10.1038/nrendo.2015.155] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The coordinated expression and activity of the iodothyronine deiodinases regulate thyroid hormone levels in hypothyroidism. Once heralded as the pathway underpinning adequate thyroid-hormone replacement therapy with levothyroxine, the role of these enzymes has come into question as they have been implicated in both an inability to normalize serum levels of tri-iodothyronine (T3) and the incomplete resolution of hypothyroid symptoms. These observations, some of which were validated in animal models of levothyroxine monotherapy, challenge the paradigm that tissue levels of T3 and thyroid-hormone signalling can be fully restored by administration of levothyroxine alone. The low serum levels of T3 observed among patients receiving levothyroxine monotherapy occur as a consequence of type 2 iodothyronine deiodinase (DIO2) in the hypothalamus being fairly insensitive to ubiquitination. In addition, residual symptoms of hypothyroidism have been linked to a prevalent polymorphism in the DIO2 gene that might be a risk factor for neurodegenerative disease. Here, we discuss how these novel findings underscore the clinical importance of iodothyronine deiodinases in hypothyroidism and how an improved understanding of these enzymes might translate to therapeutic advances in the care of millions of patients with this condition.
Collapse
Affiliation(s)
- Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Szigony Street 43, Budapest H-1083, Hungary
| | - Elizabeth A McAninch
- Division of Endocrinology and Metabolism, Rush University Medical Center, 212 Cohn Building, 1735 West Harrison Street, Chicago, IL 60612, USA
| | - Miriam O Ribeiro
- Developmental Disorders Program, Center for Biological and Health Science, Mackenzie Presbyterian University, Rua da Consolação 930, Building 16, São Paulo, SP 01302, Brazil
| | - Antonio C Bianco
- Division of Endocrinology and Metabolism, Rush University Medical Center, 212 Cohn Building, 1735 West Harrison Street, Chicago, IL 60612, USA
| |
Collapse
|
33
|
Wirth EK, Rijntjes E, Meyer F, Köhrle J, Schweizer U. High T3, Low T4 Serum Levels in Mct8 Deficiency Are Not Caused by Increased Hepatic Conversion through Type I Deiodinase. Eur Thyroid J 2015; 4:87-91. [PMID: 26601078 PMCID: PMC4640264 DOI: 10.1159/000381021] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2014] [Revised: 02/16/2015] [Indexed: 01/22/2023] Open
Abstract
BACKGROUND The Allan-Herndon-Dudley syndrome is a severe psychomotor retardation accompanied by specific changes in circulating thyroid hormone levels (high T3, low T4). These are caused by mutations in the thyroid hormone transmembrane transport protein monocarboxylate transporter 8 (MCT8). OBJECTIVE To test the hypothesis that circulating low T4 and high T3 levels are caused by enhanced conversion of T4 via increased activity of hepatic type I deiodinase (Dio1). METHODS We crossed mice deficient in Mct8 with mice lacking Dio1 activity in hepatocytes. Translation of the selenoenzyme Dio1 was abrogated by hepatocyte-specific inactivation of selenoprotein biosynthesis. RESULTS Inactivation of Dio1 activity in the livers of global Mct8-deficient mice does not restore normal circulating thyroid hormone levels. CONCLUSIONS Our data suggest that although hepatic Dio1 activity is increased in Mct8-deficient mice, it does not cause the observed abnormal circulating thyroid hormone levels. Since global inactivation of Dio1 in Mct8-deficient mice does normalize circulating thyroid hormone levels, the underlying mechanism and relevant tissues involved remain to be elucidated.
Collapse
Affiliation(s)
- Eva K. Wirth
- *Dr. Eva K. Wirth, Institut für Experimentelle Endokrinologie, Charité-Universitätsmedizin Berlin, Augustenburger Platz 1, DE-13353 Berlin (Germany), E-Mail
| | | | | | | | | |
Collapse
|
34
|
Abstract
The cellular influx and efflux of thyroid hormones are facilitated by transmembrane protein transporters. Of these transporters, monocarboxylate transporter 8 (MCT8) is the only one specific for the transport of thyroid hormones and some of their derivatives. Mutations in SLC16A2, the gene that encodes MCT8, lead to an X-linked syndrome with severe neurological impairment and altered concentrations of thyroid hormones. Histopathological analysis of brain tissue from patients who have impaired MCT8 function indicates that brain lesions start prenatally, and are most probably the result of cerebral hypothyroidism. A Slc16a2 knockout mouse model has revealed that Mct8 is an important mediator of thyroid hormone transport, especially T3, through the blood-brain barrier. However, unlike humans with an MCT8 deficiency, these mice do not have neurological impairment. One explanation for this discrepancy could be differences in expression of the T4 transporter OATP1C1 in the blood-brain barrier; OATP1C1 is more abundant in rodents than in primates and permits the passage of T4 in the absence of T3 transport, thus preventing full cerebral hypothyroidism. In this Review, we discuss the relevance of thyroid hormone transporters in health and disease, with a particular focus on the pathophysiology of MCT8 mutations.
Collapse
Affiliation(s)
- Juan Bernal
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Arturo Duperier 4, 28029 Madrid, Spain
| | - Ana Guadaño-Ferraz
- Instituto de Investigaciones Biomédicas, Consejo Superior de Investigaciones Científicas (CSIC), Universidad Autónoma de Madrid (UAM), Arturo Duperier 4, 28029 Madrid, Spain
| | - Beatriz Morte
- Centre for Biomedical Research on Rare Diseases (CIBERER), Instituto de Salud Carlos III, Arturo Duperier 4, 28029 Madrid, Spain
| |
Collapse
|
35
|
Thyroid hormone regulation of gene expression in primary cerebrocortical cells: role of thyroid hormone receptor subtypes and interactions with retinoic acid and glucocorticoids. PLoS One 2014; 9:e91692. [PMID: 24618783 PMCID: PMC3950245 DOI: 10.1371/journal.pone.0091692] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 02/14/2014] [Indexed: 01/17/2023] Open
Abstract
The effects of thyroid hormone on brain development and function are largely mediated by the binding of 3,5,3'-triiodo-L-thyronine (T3) to its nuclear receptors (TR) to regulate positively or negatively gene expression. We have analyzed by quantitative polymerase chain reaction the effect of T3 on primary cultured cells from the embryonic mouse cerebral cortex, on the expression of Hr, Klf9, Shh, Dio3, Aldh1a1, and Aldh1a3. In particular we focused on T3 receptor specificity, and on the crosstalk between T3, retinoic acid and dexamethasone. To check for receptor subtype specificity we used cerebrocortical cells derived from wild type mice and from mice deficient in thyroid hormone receptor subtypes. Receptor subtype specificity was found for Dio3 and Aldh1a1, which were induced by T3 only in cells expressing the T3 receptor alpha 1 subtype. Interactions of T3 with retinoic acid signaling through the control of retinoic acid metabolism are likely to be important during development. T3 had opposing influences on retinoic acid synthesizing enzymes, increasing the expression of Aldh1a1, and decreasing Aldh1a3, while increasing the retinoic acid degrading enzyme Cyp26b1. Dexamethasone increased Klf9 and Aldh1a1 expression. The effects of T3 and dexamethasone on Aldh1a1 were highly synergistic, with mRNA increments of up to 20 fold. The results provide new data on thyroid hormone regulation of gene expression and underscore the importance of thyroid hormone interactions with retinoic acid and glucocorticoids during neural development.
Collapse
|
36
|
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.
Collapse
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.
| |
Collapse
|
37
|
Selmi-Ruby S, Bouazza L, Obregon MJ, Conscience A, Flamant F, Samarut J, Borson-Chazot F, Rousset B. The targeted inactivation of TRβ gene in thyroid follicular cells suggests a new mechanism of regulation of thyroid hormone production. Endocrinology 2014; 155:635-46. [PMID: 24265449 DOI: 10.1210/en.2013-1435] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Thyroid epithelial cells, or thyrocytes, express functional thyroid hormone receptors but no precise role has yet been assigned to either TRα or TRβ in the thyroid gland. In this study, we analyzed the impact of inactivating the TRβ gene in the thyroid of mice. First, we generated a mouse line named Thyr-Cre, expressing the Cre recombinase under the control of the thyroglobulin gene promoter, which led to a complete recombination of floxed genes in thyrocytes. Thyr-Cre mice were then crossed with TRβ floxed mice (TRβ(flox/flox)) to obtain a thyrocyte-selective deletion of TRβ. Thyr-TRβ(-/-) mice were characterized by a decrease in the size and functional activity of the thyroid gland. These alterations were associated with a decrease in plasma TSH concentration. Surprisingly, Thyr-TRβ(-/-) displayed elevated serum T(4) and rT(3) concentrations with no significant change in serum T(3) levels. Their intrathyroidal free T(4) and rT(3) contents were also elevated, whereas the ratio of serum T(4) to thyroid free T(4) was decreased by comparison with wild-type littermates. Also, within the thyroid, deiodinases D1 and D2 were reduced as well as the expression levels of genes encoding monocarboxylate transporters (Mct8 and Mct10). Such a decrease in intrathyroidal deiodination of T(4) and in the expression of genes encoding thyroid hormone transporters may contribute to the primary overproduction of T(4) observed in Thyr-TRβ(-/-) mice. In conclusion, these data show that the control of thyroid hormone production involves not only TRβ-dependent mechanisms acting at the level of hypothalamus and pituitary but also TRβ-dependent mechanisms acting at the thyroid level.
Collapse
Affiliation(s)
- Samia Selmi-Ruby
- Inserm Unité 1052 (S.S.-R., F.B.-C., B.R.), Lyon, France; Centre National de la Recherche Scientifique Unité Mixte de Recherche 5286 (S.S.-R., F.B.-C., B.R.), Lyon, France; Université Claude Bernard Lyon 1 (S.S.-R., L.B., F.B.-C., B.R.), Faculté de Médecine Lyon-Est-Site Laennec, Lyon Cedex 08, F-69372 France; Instituto de Investigaciones Biomedicas (Consejo Superior de Investigaciones Científicas-Universidad Autonoma Madrid) (M.-J.O.), Madrid, M-28029 Spain; and Institut de Génomique Fonctionnelle de Lyon (A.C., F.F., J.S.), Lyon, F-69007 France
| | | | | | | | | | | | | | | |
Collapse
|
38
|
Müller J, Mayerl S, Visser TJ, Darras VM, Boelen A, Frappart L, Mariotta L, Verrey F, Heuer H. Tissue-specific alterations in thyroid hormone homeostasis in combined Mct10 and Mct8 deficiency. Endocrinology 2014; 155:315-25. [PMID: 24248460 DOI: 10.1210/en.2013-1800] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The monocarboxylate transporter Mct10 (Slc16a10; T-type amino acid transporter) facilitates the cellular transport of thyroid hormone (TH) and shows an overlapping expression with the well-established TH transporter Mct8. Because Mct8 deficiency is associated with distinct tissue-specific alterations in TH transport and metabolism, we speculated that Mct10 inactivation may compromise the tissue-specific TH homeostasis as well. However, analysis of Mct10 knockout (ko) mice revealed normal serum TH levels and tissue TH content in contrast to Mct8 ko mice that are characterized by high serum T3, low serum T4, decreased brain TH content, and increased tissue TH concentrations in the liver, kidneys, and thyroid gland. Surprisingly, mice deficient in both TH transporters (Mct10/Mct8 double knockout [dko] mice) showed normal serum T4 levels in the presence of elevated serum T3, indicating that the additional inactivation of Mct10 partially rescues the phenotype of Mct8 ko mice. As a consequence of the normal serum T4, brain T4 content and hypothalamic TRH expression were found to be normalized in the Mct10/Mct8 dko mice. In contrast, the hyperthyroid situation in liver, kidneys, and thyroid gland of Mct8 ko mice was even more severe in Mct10/Mct8 dko animals, suggesting that in these organs, both transporters contribute to the TH efflux. In summary, our data indicate that Mct10 indeed participates in tissue-specific TH transport and also contributes to the generation of the unusual serum TH profile characteristic for Mct8 deficiency.
Collapse
Affiliation(s)
- Julia Müller
- Leibniz Institute for Age Research/Fritz Lipmann Institute (J.M., S.M., L.F., H.H.), Jena, Germany; Department of Internal Medicine (T.J.V.), Erasmus Medical Center, Rotterdam, The Netherlands; Laboratory of Comparative Endocrinology (V.M.D.), Biology Department, Katholieke Universiteit Leuven, Leuven, Belgium; Department of Endocrinology and Metabolism (A.B.), Academic Medical Center, Amsterdam, The Netherlands; Institute of Physiology and Zürich Center for Integrative Human Physiology (L.M., F.V.), University of Zürich, Zürich, Switzerland; and Leibniz Institute for Environmental Medicine (H.H.), Düsseldorf, Germany
| | | | | | | | | | | | | | | | | |
Collapse
|
39
|
Schroeder AC, Privalsky ML. Thyroid hormones, t3 and t4, in the brain. Front Endocrinol (Lausanne) 2014; 5:40. [PMID: 24744751 PMCID: PMC3978256 DOI: 10.3389/fendo.2014.00040] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 03/17/2014] [Indexed: 12/24/2022] Open
Abstract
Thyroid hormones (THs) are essential for fetal and post-natal nervous system development and also play an important role in the maintenance of adult brain function. Of the two major THs, T4 (3,5,3',5'-tetraiodo-l-thyronine) is classically viewed as an pro-hormone that must be converted to T3 (3,5,3'-tri-iodo-l-thyronine) via tissue-level deiodinases for biological activity. THs primarily mediate their effects by binding to thyroid hormone receptor (TR) isoforms, predominantly TRα1 and TRβ1, which are expressed in different tissues and exhibit distinctive roles in endocrinology. Notably, the ability to respond to T4 and to T3 differs for the two TR isoforms, with TRα1 generally more responsive to T4 than TRβ1. TRα1 is also the most abundantly expressed TR isoform in the brain, encompassing 70-80% of all TR expression in this tissue. Conversion of T4 into T3 via deiodinase 2 in astrocytes has been classically viewed as critical for generating local T3 for neurons. However, deiodinase-deficient mice do not exhibit obvious defectives in brain development or function. Considering that TRα1 is well-established as the predominant isoform in brain, and that TRα1 responds to both T3 and T4, we suggest T4 may play a more active role in brain physiology than has been previously accepted.
Collapse
Affiliation(s)
- Amy C. Schroeder
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California Davis, Davis, CA, USA
| | - Martin L. Privalsky
- Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California Davis, Davis, CA, USA
- *Correspondence: Martin L. Privalsky, Department of Microbiology and Molecular Genetics, College of Biological Sciences, University of California Davis, One Shields Avenue, Davis, CA 95616, USA e-mail:
| |
Collapse
|
40
|
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] [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.
Collapse
Affiliation(s)
- Caterina Di Cosmo
- MD, PhD, The University of Chicago, MC3090, 5841 South Maryland Avenue, Chicago, Illinois 60637.
| | | | | | | | | | | | | |
Collapse
|
41
|
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] [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.
Collapse
Affiliation(s)
- W Edward Visser
- Department of Internal Medicine, Erasmus Medical Centre, Rotterdam, The Netherlands
| | | | | | | |
Collapse
|
42
|
Fu J, Refetoff S, Dumitrescu AM. Inherited defects of thyroid hormone-cell-membrane transport: review of recent findings. Curr Opin Endocrinol Diabetes Obes 2013; 20:434-40. [PMID: 23974772 PMCID: PMC4061907 DOI: 10.1097/01.med.0000432531.03233.ad] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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.
Collapse
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
| | | |
Collapse
|
43
|
Ock S, Ahn J, Lee SH, Kang H, Offermanns S, Ahn HY, Jo YS, Shong M, Cho BY, Jo D, Abel ED, Lee TJ, Park WJ, Lee IK, Kim J. IGF-1 receptor deficiency in thyrocytes impairs thyroid hormone secretion and completely inhibits TSH-stimulated goiter. FASEB J 2013; 27:4899-908. [PMID: 23982142 DOI: 10.1096/fj.13-231381] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Although thyroid-stimulating hormone (TSH) is known to be a major regulator of thyroid hormone biosynthesis and thyroid growth, insulin-like growth factor 1 (IGF-1) is required for mediating thyrocyte growth in concert with TSH in vitro. We generated mice with thyrocyte-selective ablation of IGF-1 receptor (TIGF1RKO) to explore the role of IGF-1 receptor signaling on thyroid function and growth. In 5-wk-old TIGF1RKO mice, serum thyroxine (T4) concentrations were decreased by 30% in concert with a 43% down-regulation of the monocarboxylate transporter 8 (MCT8), which is involved in T4 secretion. Despite a 3.5-fold increase in circulating concentrations of TSH, thyroid architecture and size were normal. Furthermore, thyrocyte area was increased by 40% in WT thyroids after 10 d TSH injection, but this effect was absent in TSH-injected TIGF1RKO mice. WT mice treated with methimazole and sodium perchlorate for 2 or 6 wk exhibited pronounced goiter development (2.0 and 5.4-fold, respectively), but in TIGF1RKO mice, goiter development was completely abrogated. These data reveal an essential role for IGF-1 receptor signaling in the regulation of thyroid function and TSH-stimulated goitrogenesis.
Collapse
Affiliation(s)
- Sangmi Ock
- 2Division of Endocrinology and Metabolism, Department of Internal Medicine, Chung-Ang University, 224-1 Heuk Seok-dong, Dongjak-ku Seoul 156-755, Korea.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
44
|
Ferrara AM, Liao XH, Gil-Ibáñez P, Marcinkowski T, Bernal J, Weiss RE, Dumitrescu AM, Refetoff S. Changes in thyroid status during perinatal development of MCT8-deficient male mice. Endocrinology 2013; 154:2533-41. [PMID: 23696569 PMCID: PMC3689279 DOI: 10.1210/en.2012-2031] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Patients with the monocarboxylate transporter 8 (MCT8) deficiency syndrome present with a severe psychomotor retardation and abnormal serum thyroid hormone (TH) levels, consisting of high T(3) and low T(4) and rT(3). Mice deficient in Mct8 replicate the thyroid phenotype of patients with the MCT8 gene mutations. We analyzed the serum TH levels and action in the cerebral cortex and in the liver during the perinatal period of mice deficient in Mct8 to assess how the thyroid abnormalities of Mct8 deficiency develop and to study the thyroidal status of specific tissues. During perinatal life, the thyroid phenotype of Mct8-deficient mice is different from that of adult mice. They manifest hyperthyroxinemia at embryonic day 18 and postnatal day 0. This perinatal hyperthyroxinemia is accompanied by manifestations of TH excess as evidenced by a relative increase in the expression of genes positively regulated by T3 in both the cerebral cortex and liver. An increased tissue accumulation of T(4) and T(3) and the expression of TH alternative transporters, including Lat1, Lat2, Oatp1c1, and Oatp3a1 in the cortex and Lat2 and Oatp1b2 in the liver, suggested that Mct8 deficiency either directly interferes with tissue efflux of TH or indirectly activates other transporters to increase TH uptake. This report is the first to identify that the ontogenesis of TH abnormalities in Mct8-deficient mice manifests with TH excess in the perinatal period.
Collapse
|
45
|
Castro I, Quisenberry L, Calvo RM, Obregon MJ, Lado-Abeal J. Septic shock non-thyroidal illness syndrome causes hypothyroidism and conditions for reduced sensitivity to thyroid hormone. J Mol Endocrinol 2013; 50:255-66. [PMID: 23296981 DOI: 10.1530/jme-12-0188] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Non-thyroidal illness syndrome (NTIS) is part of the neuroendocrine response to stress, but the significance of this syndrome remains uncertain. The aim of this study was to investigate the effect of lipopolysaccharide (LPS)-induced NTIS on thyroid hormone (TH) levels and TH molecular targets, as well as the relationship between septic shock nuclear factor kappa-light-chain-enhancer of activated B cells (NF-kB) activation and TH receptor β (THRB) gene expression at a multi-tissue level in a pig model. Prepubertal domestic pigs were given i.v. saline or LPS for 48 h. Serum and tissue TH was measured by chemiluminescence and RIA. Expression of THRs and cofactors was measured by real-time PCR, and deiodinase (DIO) activity was measured by enzyme assays. Tissue NF-kB nuclear binding activity was evaluated by EMSA. LPS-treated pigs had decreased TH levels in serum and most tissues. DIO1 expression in liver and kidney and DIO1 activity in kidney decreased after LPS. No changes in DIO2 activity were observed between groups. LPS induced an increase in hypothalamus, thyroid, and liver DIO3 activity. Among the other studied genes, monocarboxylate transporter 8 and THRB were the most commonly repressed in endotoxemic pigs. LPS-induced NF-kB activation was associated with a decrease in THRB gene expression only in frontal lobe, adrenal gland, and kidney cortex. We conclude that LPS-induced NTIS in pigs is characterized by hypothyroidism and tissue-specific reduced TH sensitivity. The role of NF-kB in regulating THRB expression during endotoxemia, if any, is restricted to a limited number of tissues.
Collapse
Affiliation(s)
- Isabel Castro
- Division of Endocrinology, Department of Internal Medicine, Texas Tech University Health Sciences Center School of Medicine, Lubbock, Texas 79430-9410, USA
| | | | | | | | | |
Collapse
|
46
|
Colin IM, Denef JF, Lengelé B, Many MC, Gérard AC. Recent insights into the cell biology of thyroid angiofollicular units. Endocr Rev 2013; 34:209-38. [PMID: 23349248 PMCID: PMC3610675 DOI: 10.1210/er.2012-1015] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/15/2012] [Accepted: 11/07/2012] [Indexed: 01/06/2023]
Abstract
In thyrocytes, cell polarity is of crucial importance for proper thyroid function. Many intrinsic mechanisms of self-regulation control how the key players involved in thyroid hormone (TH) biosynthesis interact in apical microvilli, so that hazardous biochemical processes may occur without detriment to the cell. In some pathological conditions, this enzymatic complex is disrupted, with some components abnormally activated into the cytoplasm, which can lead to further morphological and functional breakdown. When iodine intake is altered, autoregulatory mechanisms outside the thyrocytes are activated. They involve adjacent capillaries that, together with thyrocytes, form the angiofollicular units (AFUs) that can be considered as the functional and morphological units of the thyroid. In response to iodine shortage, a rapid expansion of the microvasculature occurs, which, in addition to nutrients and oxygen, optimizes iodide supply. These changes are triggered by angiogenic signals released from thyrocytes via a reactive oxygen species/hypoxia-inducible factor/vascular endothelial growth factor pathway. When intra- and extrathyrocyte autoregulation fails, other forms of adaptation arise, such as euthyroid goiters. From onset, goiters are morphologically and functionally heterogeneous due to the polyclonal nature of the cells, with nodules distributed around areas of quiescent AFUs containing globules of compact thyroglobulin (Tg) and surrounded by a hypotrophic microvasculature. Upon TSH stimulation, quiescent AFUs are activated with Tg globules undergoing fragmentation into soluble Tg, proteins involved in TH biosynthesis being expressed and the local microvascular network extending. Over time and depending on physiological needs, AFUs may undergo repetitive phases of high, moderate, or low cell and tissue activity, which may ultimately culminate in multinodular goiters.
Collapse
Affiliation(s)
- Ides M Colin
- Pôle de Morphologie, Institut de Recherche Expérimentale et Clinique, Secteur des Sciences de la Santé, Université Catholique de Louvain (UCL), UCL-5251, 52 Avenue E. Mounier, B-1200, Bruxelles, Belgium.
| | | | | | | | | |
Collapse
|
47
|
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] [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.
Collapse
Affiliation(s)
- W Edward Visser
- Department of Internal Medicine, Erasmus Medical Center, Dr Molewaterplein 50, Rotterdam, The Netherlands
| | | | | | | | | | | |
Collapse
|
48
|
|
49
|
Sosic-Jurjevic B, Filipovic B, Renko K, Ajdzanovic V, Manojlovic-Stojanoski M, Milosevic V, Köhrle J. Orchidectomy of middle-aged rats decreases liver deiodinase 1 and pituitary deiodinase 2 activity. J Endocrinol 2012; 215:247-56. [PMID: 22956722 DOI: 10.1530/joe-12-0336] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Endogenous androgens are involved in regulation of thyroid function and metabolism of thyroid hormones. As serum testosterone level progressively declines with age, this regulation may change. We tested how androgen deprivation, achieved by orchidectomy, affects thyroid homeostasis in middle-aged rats. Fifteen-month-old Wistar rats were orchidectomized (Orx) or sham-operated under ketamine anesthesia (15 mg/kg body weight). Five weeks after the surgery, animals were decapitated. Thyroids were used for histomorphometric and ultrastructural examinations and together with livers and pituitaries for real-time quantitative PCR and deiodinase (DIO) activity measurements. Serum testosterone, TSH, l-thyroxine (T(4)), and cholesterol (Chol) levels were determined. As expected, middle-aged control rats had lower (P<0.05) testosterone and T(4) compared with 3-month-old males. In the Orx middle-aged group, we detected diminished serum testosterone (P<0.05), no change in TSH and T(4) levels, and higher Chol level (P<0.05), in comparison with age-matched controls. Histomorphometric analysis of thyroid tissue revealed decreased relative volume densities of follicles and colloid (P<0.05). Relevant gene expressions and DIO1 enzyme activity were not changed in the thyroids of Orx rats. Liver Dio1 gene expression and DIO1 activity were decreased (P<0.05) in comparison with the control values. Pituitary levels of TSHβ, Dio1, and Dio2 mRNAs did not change, while DIO2 activity decreased (P<0.05). In conclusion, orchidectomy of middle-aged rats affected thyroid structure with no effect on serum T(4) and TSH. However, decreased liver DIO1 and pituitary DIO2 enzyme activities indicate compensatory-adaptive changes in local T(3) production.
Collapse
Affiliation(s)
- Branka Sosic-Jurjevic
- Department of Cytology, Institute for Biological Research 'Siniša Stanković', University of Belgrade, Despot Stefan Boulevard, Belgrade, Serbia.
| | | | | | | | | | | | | |
Collapse
|
50
|
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] [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.
Collapse
|