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Bianco AC, Anderson G, Forrest D, Galton VA, Gereben B, Kim BW, Kopp PA, Liao XH, Obregon MJ, Peeters RP, Refetoff S, Sharlin DS, Simonides WS, Weiss RE, Williams GR. American Thyroid Association Guide to investigating thyroid hormone economy and action in rodent and cell models. Thyroid 2014; 24:88-168. [PMID: 24001133 PMCID: PMC3887458 DOI: 10.1089/thy.2013.0109] [Citation(s) in RCA: 143] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND An in-depth understanding of the fundamental principles that regulate thyroid hormone homeostasis is critical for the development of new diagnostic and treatment approaches for patients with thyroid disease. SUMMARY Important clinical practices in use today for the treatment of patients with hypothyroidism, hyperthyroidism, or thyroid cancer are the result of laboratory discoveries made by scientists investigating the most basic aspects of thyroid structure and molecular biology. In this document, a panel of experts commissioned by the American Thyroid Association makes a series of recommendations related to the study of thyroid hormone economy and action. These recommendations are intended to promote standardization of study design, which should in turn increase the comparability and reproducibility of experimental findings. CONCLUSIONS It is expected that adherence to these recommendations by investigators in the field will facilitate progress towards a better understanding of the thyroid gland and thyroid hormone dependent processes.
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Affiliation(s)
- Antonio C. Bianco
- Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, Florida
| | - Grant Anderson
- Department of Pharmacy Practice and Pharmaceutical Sciences, College of Pharmacy, University of Minnesota Duluth, Duluth, Minnesota
| | - Douglas Forrest
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
| | - Valerie Anne Galton
- Department of Physiology and Neurobiology, Dartmouth Medical School, Lebanon, New Hampshire
| | - Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest, Hungary
| | - Brian W. Kim
- Division of Endocrinology, Diabetes and Metabolism, University of Miami Miller School of Medicine, Miami, Florida
| | - Peter A. Kopp
- Division of Endocrinology, Metabolism, and Molecular Medicine, and Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois
| | - Xiao Hui Liao
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois
| | - Maria Jesus Obregon
- Institute of Biomedical Investigation (IIB), Spanish National Research Council (CSIC) and Autonomous University of Madrid, Madrid, Spain
| | - Robin P. Peeters
- Division of Endocrinology, Department of Internal Medicine, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Samuel Refetoff
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois
| | - David S. Sharlin
- Department of Biological Sciences, Minnesota State University, Mankato, Minnesota
| | - Warner S. Simonides
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Roy E. Weiss
- Section of Adult and Pediatric Endocrinology, Diabetes, and Metabolism, The University of Chicago, Chicago, Illinois
| | - Graham R. Williams
- Department of Medicine, Imperial College London, Hammersmith Campus, London, United Kingdom
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Hamidi S, Aliesky HA, Williams RW, Rapoport B, McLachlan SM. Genetic linkages for thyroxine released in response to thyrotropin stimulation in three sets of recombinant inbred mice provide evidence for shared and novel genes controlling thyroid function. Thyroid 2013; 23:360-70. [PMID: 22988948 PMCID: PMC3593690 DOI: 10.1089/thy.2012.0338] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
BACKGROUND Graves' hyperthyroidism is induced by immunizing mice with adenovirus expressing the human thyrotropin (TSH)-receptor. Using families of recombinant-inbred mice, we previously discovered that genetic susceptibility to induced thyroid-stimulating antibodies and hyperthyroidism are linked to loci on different chromosomes, indicating a fundamental genetic difference in thyroid sensitivity to ligand stimulation. An approach to assess thyroid sensitivity involves challenging genetically diverse lines of mice with TSH and measuring the genotype/strain-specific increase in serum thyroxine (T4). METHODS We investigated genetic susceptibility and genetic control of T4 stimulation by 10 mU bovine TSH in female mice of the CXB, BXH, and AXB/BXA strain families, all previously studied for induced Graves' hyperthyroidism. RESULTS Before TSH injection, T4 levels must be suppressed by inhibiting endogenous TSH secretion. Three daily intraperitoneal L-triiodothyronine injections efficiently suppressed serum T4 in females of 50 of 51 recombinant inbred strains. T4 stimulation by TSH was more strongly linked in CXB and BXH sets, derived from parental strains with divergent T4 stimulation, than in AXB/BXA strains generated from parents with similar TSH-induced responses. Genetic loci linked to the acute TSH-induced T4 response (hours) were not the same as those linked to induced hyperthyroidism (which develops over months). CONCLUSIONS Genetic susceptibility for thyroid sensitivity to TSH stimulation was distinct for three families of inbred mouse lines. These observations parallel the human situation with multiple genetic loci contributing to the same trait and different loci associated with the same trait in different ethnic groups. Of the genetic loci highlighted in mice, three overlap with, or are located up or downstream, of human TSH-controlling genes. Other studies show that human disease genes can be identified through cross-species gene mapping of evolutionary conserved processes. Consequently, our findings suggest that novel thyroid function genes may yet be revealed in humans.
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Affiliation(s)
- Sepehr Hamidi
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Research Institute, Los Angeles, California
- The David Geffen School of Medicine, University of California, Los Angeles, California
| | - Holly A. Aliesky
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Research Institute, Los Angeles, California
| | - Robert W. Williams
- Department of Anatomy and Neurobiology, University of Tennessee Health-Science Center, Memphis, Tennessee
| | - Basil Rapoport
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Research Institute, Los Angeles, California
- The David Geffen School of Medicine, University of California, Los Angeles, California
| | - Sandra M. McLachlan
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Research Institute, Los Angeles, California
- The David Geffen School of Medicine, University of California, Los Angeles, California
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Chiappini F, Ramadoss P, Vella KR, Cunha LL, Ye FD, Stuart RC, Nillni EA, Hollenberg AN. Family members CREB and CREM control thyrotropin-releasing hormone (TRH) expression in the hypothalamus. Mol Cell Endocrinol 2013; 365:84-94. [PMID: 23000398 PMCID: PMC3572472 DOI: 10.1016/j.mce.2012.09.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 09/05/2012] [Accepted: 09/11/2012] [Indexed: 01/19/2023]
Abstract
Thyrotropin-releasing hormone (TRH) in the paraventricular nucleus (PVN) of the hypothalamus is regulated by thyroid hormone (TH). cAMP response element binding protein (CREB) has also been postulated to regulate TRH expression but its interaction with TH signaling in vivo is not known. To evaluate the role of CREB in TRH regulation in vivo, we deleted CREB from PVN neurons to generate the CREB1(ΔSIM1) mouse. As previously shown, loss of CREB was compensated for by an up-regulation of CREM in euthyroid CREB1(ΔSIM1) mice but TSH, T₄ and T₃ levels were normal, even though TRH mRNA levels were elevated. Interestingly, TRH mRNA expression was also increased in the PVN of CREB1(ΔSIM1) mice in the hypothyroid state but became normal when made hyperthyroid. Importantly, CREM levels were similar in CREB1(ΔSIM1) mice regardless of thyroid status, demonstrating that the regulation of TRH by T₃ in vivo likely occurs independently of the CREB/CREM family.
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Affiliation(s)
- Franck Chiappini
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
- Address correspondence and reprint request to: Dr. Franck Chiappini or Dr. Anthony Hollenberg, MD, 330 Brookline Avenue, E/CLS 0728, MA, 02215. Tel: 617-735-3268. Fax: 617-735-3323; ,
| | - Preeti Ramadoss
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Kristen R. Vella
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Lucas L. Cunha
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Felix D. Ye
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
| | - Ronald C. Stuart
- Division of Endocrinology, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI 02903. ;
| | - Eduardo A. Nillni
- Division of Endocrinology, The Warren Alpert Medical School of Brown University, Rhode Island Hospital, Providence, RI 02903. ;
| | - Anthony N. Hollenberg
- Division of Endocrinology, Diabetes and Metabolism. Beth Israel Deaconess Medical Center and Harvard Medical School. Center of Life Science, Boston, MA, 02115. ; ; ; ; ;
- Address correspondence and reprint request to: Dr. Franck Chiappini or Dr. Anthony Hollenberg, MD, 330 Brookline Avenue, E/CLS 0728, MA, 02215. Tel: 617-735-3268. Fax: 617-735-3323; ,
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Müller K, Führer D, Mittag J, Klöting N, Blüher M, Weiss RE, Many MC, Schmid KW, Krohn K. TSH compensates thyroid-specific IGF-I receptor knockout and causes papillary thyroid hyperplasia. Mol Endocrinol 2011; 25:1867-79. [PMID: 21980075 DOI: 10.1210/me.2011-0065] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Although TSH stimulates all aspects of thyroid physiology IGF-I signaling through a tyrosine kinase-containing transmembrane receptor exhibits a permissive impact on TSH action. To better understand the importance of the IGF-I receptor in the thyroid in vivo, we inactivated the Igf1r with a Tg promoter-driven Cre-lox system in mice. We studied male and female mice with thyroidal wild-type, Igf1r(+/-), and Igf1r(-/-) genotypes. Targeted Igf1r inactivation did transiently reduce thyroid hormone levels and significantly increased TSH levels in both heterozygous and homozygous mice without affecting thyroid weight. Histological analysis of thyroid tissue with Igf1r inactivation revealed hyperplasia and heterogeneous follicle structure. From 4 months of age, we detected papillary thyroid architecture in heterozygous and homozygous mice. We also noted increased body weight of male mice with a homozygous thyroidal null mutation in the Igf1r locus, compared with wild-type mice, respectively. A decrease of mRNA and protein for thyroid peroxidase and increased mRNA and protein for IGF-II receptor but no significant mRNA changes for the insulin receptor, the TSH receptor, and the sodium-iodide-symporter in both Igf1r(+/-) and Igf1r(-/-) mice were detected. Our results suggest that the strong increase of TSH benefits papillary thyroid hyperplasia and completely compensates the loss of IGF-I receptor signaling at the level of thyroid hormones without significant increase in thyroid weight. This could indicate that the IGF-I receptor signaling is less essential for thyroid hormone synthesis but maintains homeostasis and normal thyroid morphogenesis.
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Affiliation(s)
- Kathrin Müller
- Department of Internal Medicine, University of Leipzig, Germany
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Hamidi S, Aliesky H, Chen CR, Rapoport B, McLachlan SM. Variable suppression of serum thyroxine in female mice of different inbred strains by triiodothyronine administered in drinking water. Thyroid 2010; 20:1157-62. [PMID: 20860425 PMCID: PMC2947419 DOI: 10.1089/thy.2010.0117] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
BACKGROUND Recombinant-inbred mouse strains differ in their susceptibility to Graves'-like hyperthyroidism induced by immunization with adenovirus expressing the human thyrotropin (TSH) receptor. Because one genetic component contributing to this susceptibility is altered thyroid sensitivity to TSH receptor agonist stimulation, we wished to quantify thyroid responsiveness to TSH. For such studies, it is necessary to suppress endogenous TSH by administering L-3,5,3′-triiodothyronine (L-T3), with the subsequent decrease in serum thyroxine (T4) reflecting endogenous TSH suppression. Our two objectives were to assess in different inbred strains of mice (i) the extent of serum T4 suppression after L-T3 administration and (ii) the magnitude of serum T4 increase induced by TSH. METHODS Mice were tail-bled to establish baseline-serum T4 before L-T3 administration. We initially employed a protocol of L-T3-supplemented drinking water for 7 days. In subsequent experiments, we injected L-T3 intraperitoneally (i.p.) daily for 3 days. Mice were then injected i.p. with bovine TSH (10 mU) and euthanized 5 hours later. Serum T4 was assayed before L-T3 administration, and before and after TSH injection. In some experiments, serum T3 and estradiol were measured in pooled sera. RESULTS Oral L-T3 (3 or 5 µg/mL) suppressed serum T4 levels by 26%-64% in female BALB/c mice but >95% in males. T4 suppression in female B6 mice ranged from 0% to 90%. In C3H mice, L-T3 at 3 µg/mL was ineffective but 5 µg/mL achieved >80% serum T4 reduction. Unlike inbred mice, in outbred CF1 mice the same protocol was more effective: 83% in females and 100% suppression in males. The degree of T4 suppression was unrelated to baseline T4, T3, or estradiol, but was related to mouse weight and postmortem T3, with greater suppression in larger mice (outbred CF1 animals and inbred males). Among females with serum T4 suppression >80%, the increase in serum T4 after TSH injection was greater for BALB/c and C3H versus B6 mice. Moreover, the T4 increment was higher in female than in male BALB/c. CONCLUSIONS Our data provide important, practical information for future in vivo studies in inbred mice: we recommend that responses to TSH be performed in female animals injected with L-T3 i.p. to suppress baseline T4.
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Affiliation(s)
- Sepehr Hamidi
- Thyroid Autoimmune Disease Unit, Cedars-Sinai Research Institute and UCLA School of Medicine, 8700 Beverly Blvd., Los Angeles, CA 90048, USA
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Sittig LJ, Redei EE. Paternal genetic contribution influences fetal vulnerability to maternal alcohol consumption in a rat model of fetal alcohol spectrum disorder. PLoS One 2010; 5:e10058. [PMID: 20383339 PMCID: PMC2850935 DOI: 10.1371/journal.pone.0010058] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2010] [Accepted: 03/15/2010] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Fetal alcohol exposure causes in the offspring a collection of permanent physiological and neuropsychological deficits collectively termed Fetal Alcohol Spectrum Disorder (FASD). The timing and amount of exposure cannot fully explain the substantial variability among affected individuals, pointing to genetic influences that mediate fetal vulnerability. However, the aspects of vulnerability that depend on the mother, the father, or both, are not known. METHODOLOGY/PRINCIPAL FINDINGS Using the outbred Sprague-Dawley (SD) and inbred Brown Norway (BN) rat strains as well as their reciprocal crosses, we administered ethanol (E), pair-fed (PF), or control (C) diets to the pregnant dams. The dams' plasma levels of free thyroxine (fT4), triiodothyronine (T3), free T3 (fT3), and thyroid stimulating hormone (TSH) were measured to elucidate potential differences in maternal thyroid hormonal environment, which affects specific aspects of FASD. We then compared alcohol-exposed, pair fed, and control offspring of each fetal strain on gestational day 21 (G21) to identify maternal and paternal genetic effects on bodyweight and placental weight of male and female fetuses. CONCLUSIONS SD and BN dams exhibited different baseline hypothalamic-pituitary-thyroid function. Moreover, the thyroid function of SD dams was more severely affected by alcohol consumption while that of BN dams was relatively resistant. This novel finding suggests that genetic differences in maternal thyroid function are one source of maternal genetic effects on fetal vulnerability to FASD. The fetal vulnerability to decreased bodyweight after alcohol exposure depended on the genetic contribution of both parents, not only maternal contribution as previously thought. In contrast, the effect of maternal alcohol consumption on placental weight was consistent and not strain-dependent. Interestingly, placental weight in fetuses with different paternal genetic contributions exhibited opposite responses to caloric restriction (pair feeding). In summary, these novel findings demonstrate both maternal and paternal genetic contributions to in utero vulnerability to alcohol, refining our understanding of the genetically-based heterogeneity seen in human FASD.
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Affiliation(s)
- Laura J. Sittig
- Asher Center, Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
| | - Eva E. Redei
- Asher Center, Department of Psychiatry and Behavioral Sciences, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States of America
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Horvath A, Faucz F, Finkielstain GP, Nikita ME, Rothenbuhler A, Almeida M, Mericq V, Stratakis CA. Haplotype analysis of the promoter region of phosphodiesterase type 8B (PDE8B) in correlation with inactivating PDE8B mutation and the serum thyroid-stimulating hormone levels. Thyroid 2010; 20:363-7. [PMID: 20373981 PMCID: PMC2867554 DOI: 10.1089/thy.2009.0260] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Human phosphodiesterase (PDE) type 8B (PDE8B) is located at 5q14.1 and is known as the PDE with the highest affinity to cAMP. We recently described a family with bilateral micronodular adrenocortical disease that was apparently caused by an inactivating PDE8B mutation (H305P). As a result of a genome-wide study, a strong association between six polymorphic variants in the PDE8B promoter and serum levels of the thyroid-stimulating hormone (TSH) has been recently reported. Despite an extended analysis of the regions surrounding 5q14.1, no other potential genetic variants that could be responsible for the associated TSH levels were found. METHODS In this study, we genotyped by polymerase chain reaction the described six polymorphic variants in the PDE8B promoter in the family with micronodular adrenocortical disease and inactivating PDE8B mutation and analyzed their correlation with individual TSH values in the family members. RESULTS We observed complete segregation between the reported association and individual TSH values in the family we studied. Haplotype analysis showed that the haplotype associated with the high TSH levels is different from the one that segregated with H305P, suggesting that the mutation most probably has arisen on an allele independent of the high TSH-associated allele. CONCLUSIONS The proposed mechanism by which PDE8B may influence TSH levels is through control of cAMP signaling. Our analysis revealed separate segregation of an inactivating PDE8B allele from the high-TSH-allele and showed low TSH levels in persons who carry an inactivating PDE8B allele. These data suggest that, indeed, PDE8B may be involved in regulation of TSH levels.
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Affiliation(s)
- Anelia Horvath
- Program on Developmental Endocrinology and Genetics, Section of Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Fabio Faucz
- Program on Developmental Endocrinology and Genetics, Section of Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
- Laboratory of Molecular Genetics, Center for Healthy and Biological Science, Pontificia Universidade Catolica do Parana, Curitiba, Brazil
| | - Gabriela P. Finkielstain
- Program on Developmental Endocrinology and Genetics, Section of Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Maria Eleni Nikita
- Program on Developmental Endocrinology and Genetics, Section of Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Anya Rothenbuhler
- Program on Developmental Endocrinology and Genetics, Section of Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Madson Almeida
- Program on Developmental Endocrinology and Genetics, Section of Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
| | - Veronica Mericq
- Faculty of Medicine, Institute of Maternal and Child Research, University of Chile, Santiago, Chile
| | - Constantine A. Stratakis
- Program on Developmental Endocrinology and Genetics, Section of Endocrinology and Genetics, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland
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Gelwane G, de Roux N, Chevenne D, Carel JC, Léger J. Pituitary-thyroid feedback in a patient with a sporadic activating thyrotropin (TSH) receptor mutation: implication that thyroid-secreted factors other than thyroid hormones contribute to serum TSH levels. J Clin Endocrinol Metab 2009; 94:2787-91. [PMID: 19454581 DOI: 10.1210/jc.2008-2524] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Constitutive mutations of the TSH receptor gene are a rare cause of severe congenital hyperthyroidism. Persistent TSH suppression has been described in euthyroid Graves' disease patients treated with antithyroid drugs. An ultrashort negative feedback loop affecting TSH secretion by activating the pituitary TSH receptor with TSH receptor autoantibodies has been suggested as a possible mechanism of TSH suppression in these patients. OBJECTIVE AND DESIGN The aim of the study was to determine whether TSH suppression also occurs in euthyroid treated patients with non-autoimmune hyperthyroidism. We investigated the outcome of pituitary-thyroid feedback in a patient carrying an activating mutation of the TSH-R gene in an observational prospective study. Repeated clinical investigations from birth until the age of 14 yr are presented for the patient on drug treatment and after radical treatment. RESULTS TSH was consistently undetectable or present at very low concentrations in the serum for several years, although FT(4) and FT(3) concentrations remained mostly in the normal range. Moreover, serum TSH concentrations increased only slightly when serum FT(4) concentrations fell below normal levels. During drug treatment, serum TSH concentrations expressed as a function of serum FT(4) and FT(3) concentrations were significantly lower than those for control or congenital hypothyroid populations. By contrast, after radical treatment, serum TSH levels increased, reaching the normal range, and low serum FT(4) and FT(3) concentrations were associated with appropriate increases in serum TSH concentrations. CONCLUSION These data provide insight into the regulation of serum TSH concentrations and suggest an alternative mechanism, in addition to serum thyroid hormone levels, for adjusting TSH secretion.
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Affiliation(s)
- Georges Gelwane
- Pediatric Endocrinology Unit, Centre de Référence Maladies Endocriniennes de la Croissance, and INSERM Unité 690, Robert Debré Hospital, Université Paris-Diderot Paris 7, 48 Boulevard Sérurier, Paris, France
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Misharin AV, Rapoport B, McLachlan SM. Thyroid antigens, not central tolerance, control responses to immunization in BALB/c versus C57BL/6 mice. Thyroid 2009; 19:503-9. [PMID: 19348579 PMCID: PMC2857445 DOI: 10.1089/thy.2008.0420] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Vaccination with cDNA for the human thyrotropin receptor (TSHR) in a plasmid, without adjuvant, induces TSHR antibodies in C57BL/6 but rarely in BALB/c mice. This outcome could be due to a difference between "high" versus "low" antibody responder mouse strains. However, unlike their poor response to TSHR-DNA vaccination, BALB/c mice vaccinated with thyroid peroxidase (TPO)-cDNA readily develop antibodies to TPO. We hypothesized that insight into these conundrums would be provided by the following differences in central tolerance: (i) between two mouse strains (C57BL/6 versus BALB/c) for the TSHR; and (ii) between two thyroid autoantigens (TPO and the TSHR) in one mouse strain (BALB/c). METHODS We studied autoantigen expression using real-time polymerase chain reaction to quantify mRNA transcripts for the TSHR, TPO, and thyroglobulin (Tg) in thymic tissue (as well as in thyroid) of young mice. RESULTS Our hypothesis was not confirmed. Intrathymic TSHR transcript expression was similar in BALB/c and C57BL/6 mice. Moreover, thymic mRNA transcripts for TSHR and TPO were comparable. Unlike the 10-fold differences for the autoantigens in thyroid tissue (Tg greater than TPO which, in turn was greater than the TSHR), intrathymic transcripts for TPO and the TSHR were similar, both being slightly lower than the level for Tg. CONCLUSIONS Central tolerance, assessed by measuring intrathymic transcripts of thyroid autoantigens, does not explain the different outcome of TSHR-DNA vaccination in BALB/c and C57BL/6 mice, or even susceptibility versus resistance to hyperthyroidism induced by TSHR-adenovirus. Instead, differences in MHC and TSHR T-cell epitopes likely contribute to TSHR antibody development (or not) following DNA plasmid immunization. The greater immunogenicity of TPO versus TSHR probably relates to the greater number of nonhomologous amino acids in the human and mouse TPO ectodomains (78 amino acids) than in the human and mouse TSHR ectodomains (58 amino acids). Overall, the autoantigens themselves, not central tolerance, control DNA plasmid-induced immunity to TPO and the TSHR.
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McLachlan SM, Aliesky HA, Pichurin PN, Chen CR, Williams RW, Rapoport B. Shared and unique susceptibility genes in a mouse model of Graves' disease determined in BXH and CXB recombinant inbred mice. Endocrinology 2008; 149:2001-9. [PMID: 18162518 PMCID: PMC2276708 DOI: 10.1210/en.2007-1517] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Susceptibility genes for TSH receptor (TSHR) antibodies and hyperthyroidism can be probed in recombinant inbred (RI) mice immunized with adenovirus expressing the TSHR A-subunit. The RI set of CXB strains, derived from susceptible BALB/c and resistant C57BL/6 (B6) mice, were studied previously. High-resolution genetic maps are also available for RI BXH strains, derived from B6 and C3H/He parents. We found that C3H/He mice develop TSHR antibodies, and some animals become hyperthyroid after A-subunit immunization. In contrast, the responses of the F1 progeny of C3H/He x B6 mice, as well as most BXH RI strains, are dominated by the B6 resistance to hyperthyroidism. As in the CXB set, linkage analysis of BXH strains implicates different chromosomes (Chr) or loci in the susceptibility to induced TSHR antibodies vs. hyperthyroidism. Importantly, BXH and CXB mice share genetic loci controlling the generation of TSHR antibodies (Chr 17, major histocompatibility complex region, and Chr X) and development of hyperthyroidism (Chr 1 and 3). Moreover, some chromosomal linkages are unique to either BXH or CXB strains. An interesting candidate gene linked to thyroid-stimulating antibody generation in BXH mice is the Ig heavy chain locus, suggesting a role for particular germline region genes as precursors for these antibodies. In conclusion, our findings reinforce the importance of major histocompatibility complex region genes in controlling the generation of TSHR antibodies measured by TSH binding inhibition. Moreover, these data emphasize the value of RI strains to dissect the genetic basis for induced TSHR antibodies vs. their effects on thyroid function in Graves' disease.
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Affiliation(s)
- Sandra M McLachlan
- Autoimmune Disease Unit, Cedars-Sinai Medical Center, 8700 Beverly Boulevard, Los Angeles, CA 90048, USA.
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