101
|
Abstract
KEY POINTS Thyroid hormones affect cardiac myocytes as well as the smooth muscle and endothelial cells of the vascular wall. Free 3,53'-L-triiodothyronine (FT3) and its specific nuclear receptor modulate the transcription of various proteins, principally those involved in the myocyte contractile apparatus (myosin heavy chains), and the regulation of intracellular calcium flux (sarcoplasmic reticulum Ca2+ATPase). Thyroid hormones also have non-genomic effects that work rapidly, complement the effects described above, and are related to alterations in the properties of many channels and membrane receptors, especially in the sinoatrial mode. Thyroid hormones also affect the smooth muscle and endothelial cells of the vascular walls and reduce systemic vascular resistance. These effects on cardiac and vascular cells globally explain the cardiac manifestations (especially the inotropic and chronotropic effects) observed during dysthyroidism, particularly in hyperthyroidism where they are often in the forefront (positive inotropic and chronotropic effects).
Collapse
|
102
|
Constantinou C, Margarity M, Valcana T. Region-specific effects of hypothyroidism on the relative expression of thyroid hormone receptors in adult rat brain. Mol Cell Biochem 2005; 278:93-100. [PMID: 16180094 DOI: 10.1007/s11010-005-6934-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2005] [Accepted: 05/04/2005] [Indexed: 11/30/2022]
Abstract
The aim of this study was to determine whether changes in the circulating thyroid hormone (TH) and brain synaptosomal TH content affected the relative levels of mRNA encoding different thyroid hormone receptor (TR) isoforms in adult rat brain. Northern analysis of polyA+RNA from cerebral cortex, hippocampus and cerebellum of control and hypothyroid adult rats was performed in order to determine the relative expression of all TR isoforms. Circulating and synaptosomal TH concentrations were determined by radioimmunoassay. Region-specific quantitative differences in the expression pattern of all TR isoforms in euthyroid animals and hypothyroid animals were recorded. In hypothyroidism, the levels of TRalpha2 mRNA (non-T3-binding isoform) were decreased in all brain regions examined. In contrast the relative expression of TRalpha1 was increased in cerebral cortex and hippocampus, whereas in cerebellum remained unaffected. The TRbeta1 relative expression in cerebral cortex and hippocampus of hypothyroid animals was not affected, whereas this TR isoform was not detectable in cerebellum. The TR isoform mRNA levels returned to control values following T4 intraperitoneal administration to the hypothyroid rats. The obtained results show that in vivo depletion of TH regulates TR gene expression in adult rat brain in a region-specific manner.
Collapse
|
103
|
Seo H, Cao X, Kambe F. [Receptor-mediated nongenomic action of thyroid hormone: T3-dependent activation of PI3K-->akt/PKB-->mTOR signaling cascade, leading to the upregulation of ZAKI-4alpha, a calcineurin inhibitor]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2005; 63 Suppl 10:16-9. [PMID: 16279596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
|
104
|
Ikuyama S. [Effects of thyroid hormone on hematopoiesis]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2005; 63 Suppl 10:84-7. [PMID: 16279608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
|
105
|
Nakamura H. [Discovery and significance of thyroid hormone and its receptors]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2005; 63 Suppl 10:11-5. [PMID: 16279595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
|
106
|
Sasaki S, Nakamura H. [Signal transduction by thyroid hormone receptors]. NIHON RINSHO. JAPANESE JOURNAL OF CLINICAL MEDICINE 2005; 63 Suppl 10:41-50. [PMID: 16279601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
|
107
|
Brown DD, Cai L, Das B, Marsh-Armstrong N, Schreiber AM, Juste R. Thyroid hormone controls multiple independent programs required for limb development in Xenopus laevis metamorphosis. Proc Natl Acad Sci U S A 2005; 102:12455-8. [PMID: 16129821 PMCID: PMC1194953 DOI: 10.1073/pnas.0505989102] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Thyroid hormone (TH) is required for limb development in Xenopus laevis. Specific cell types in the growing limb were targeted for expression of a dominant negative form of the TH receptor by sperm-mediated transgenesis. Limb muscle development, the innervation of muscle from the spinal cord, and cartilage growth can be inhibited without affecting patterning of the limb or differentiation of other cell types. Remodeling of the skin occurs late in metamorphosis after the limb has formed. The coordination of these independent programs is affected in part by the control that TH exerts over DNA replication in all cell types of the limb.
Collapse
|
108
|
Bergh JJ, Lin HY, Lansing L, Mohamed SN, Davis FB, Mousa S, Davis PJ. Integrin alphaVbeta3 contains a cell surface receptor site for thyroid hormone that is linked to activation of mitogen-activated protein kinase and induction of angiogenesis. Endocrinology 2005; 146:2864-71. [PMID: 15802494 DOI: 10.1210/en.2005-0102] [Citation(s) in RCA: 407] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Integrin alpha(V)beta(3) is a heterodimeric plasma membrane protein whose several extracellular matrix protein ligands contain an RGD recognition sequence. This study identifies integrin alpha(V)beta(3) as a cell surface receptor for thyroid hormone [L-T(4) (T(4))] and as the initiation site for T(4)-induced activation of intracellular signaling cascades. Integrin alpha(V)beta(3) dissociably binds radiolabeled T(4) with high affinity, and this binding is displaced by tetraiodothyroacetic acid, alpha(V)beta(3) antibodies, and an integrin RGD recognition site peptide. CV-1 cells lack nuclear thyroid hormone receptor, but express plasma membrane alpha(V)beta(3); treatment of these cells with physiological concentrations of T(4) activates the MAPK pathway, an effect inhibited by tetraiodothyroacetic acid, RGD peptide, and alpha(V)beta(3) antibodies. Inhibitors of T(4) binding to the integrin also block the MAPK-mediated proangiogenic action of T(4). T(4)-induced phosphorylation of MAPK is inhibited by small interfering RNA knockdown of alpha(V) and beta(3). These findings suggest that T(4) binds to alpha(V)beta(3) near the RGD recognition site and show that hormone-binding to alpha(V)beta(3) has physiological consequences.
Collapse
|
109
|
|
110
|
Jetten AM. Recent advances in the mechanisms of action and physiological functions of the retinoid-related orphan receptors (RORs). ACTA ACUST UNITED AC 2005; 3:395-412. [PMID: 15584888 DOI: 10.2174/1568010042634497] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Retinoid-related orphan receptors ROR alpha, -beta, and -gamma are evolutionarily related transcription factors belonging to the steroid hormone receptor superfamily. Studies of ROR mutant mice revealed that these receptors are critical in the regulation of a number of physiological processes. ROR alpha plays a key role in the development of the cerebellum particularly in the regulation of Purkinje cell differentiation and proliferation of granule cell progenitors. ROR alpha has also been implicated in the maintenance of bone tissue and mice deficient in ROR alpha exhibit a greater susceptibility to atherosclerosis. ROR gamma is essential for lymph node organogenesis and plays a key role in the generation or survival of lymphoid tissue inducer (Lti) cells. ROR gamma is also critical in thymopoiesis where it controls differentiation and promotes the survival of thymocytes by positively regulating Bcl-X(L) expression. Several studies have indicated a regulatory role for RORs in circadian behavior. In several tissues, the expression of RORs oscillates during circadian rhythm while mice deficient in ROR beta exhibit an altered circadian rhythm. ROR alpha and ROR gamma have been implicated in the control of various immune responses. Mice deficient in ROR gamma exhibit a reduced susceptibility to allergen-induced airway inflammation while ROR alpha null mice show a prolonged inflammatory response to lipopolysaccharide. Recent analyses of the crystal structure and transcriptional activity of RORs revealed that cholesterol and specific cholesterol derivatives behave as agonists of ROR alpha while certain retinoids function as partial antagonists of ROR beta and ROR gamma. These studies indicate that ROR activity and, as a consequence physiological processes regulated by RORs, can be modulated by exogenous (ant)agonists. Therefore, the discovery of new (ant)agonists may lead to the development of novel therapeutic strategies for human disease in which RORs have been implicated.
Collapse
MESH Headings
- Animals
- Cell Differentiation
- Cell Proliferation
- Circadian Rhythm
- Humans
- Inflammation/immunology
- Lymphatic System/growth & development
- Nuclear Receptor Subfamily 1, Group F, Member 1
- Nuclear Receptor Subfamily 1, Group F, Member 2
- Nuclear Receptor Subfamily 1, Group F, Member 3
- Purkinje Cells/cytology
- Receptors, Cytoplasmic and Nuclear/genetics
- Receptors, Cytoplasmic and Nuclear/physiology
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/physiology
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/physiology
- Thymus Gland/cytology
- Thymus Gland/immunology
- Trans-Activators/genetics
- Trans-Activators/physiology
- Transcription Factors/genetics
- Transcription Factors/physiology
- Transcription, Genetic
Collapse
|
111
|
Jho SH, Vouthounis C, Lee B, Stojadinovic O, Im MJ, Brem H, Merchant A, Chau K, Tomic-Canic M. The Book of Opposites: The Role of the Nuclear Receptor Co-regulators in the Suppression of Epidermal Genes by Retinoic Acid and Thyroid Hormone Receptors. J Invest Dermatol 2005; 124:1034-43. [PMID: 15854046 DOI: 10.1111/j.0022-202x.2005.23691.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Transcriptional regulation by nuclear receptors occurs through complex interactions that involve DNA response elements, co-activators/co-repressors, and histone modifying enzymes. Very little is known about how molecular interplay of these components may determine tissue specificity of hormone action. We have shown previously that retinoic acid (RA) and thyroid hormone (T3) repress transcription of a specific group of epidermal keratin genes through a novel mechanism that utilizes receptors homodimers. In this paper, we have analyzed the epidermal specificity of RA/T3 action by testing the role of co-repressors and co-activators in regulation of epidermal genes. Using transient co-transfections, northern blots, antisense oligonucleotides, and a histone deacetylase (HDAC) inhibitor, trichostatin A, we found that in the context of specific keratin RE (KRE), co-activators and histone acetylase become co-repressors of the RA/T3 receptors in the presence of their respective ligands. Conversely, co-repressors and HDAC become co-activators of unliganded T3Ralpha. The receptor-co-activator interaction is intact and occurs through the NR-box. Therefore, the role of co-activator is to associate with liganded receptors whereas the KRE-receptor interaction determines specific transcriptional signal, in this case repression. This novel molecular mechanism of transcriptional repression conveys how RA and T3 target specific groups of epidermal genes, thus exerting intrinsic tissue specificity.
Collapse
|
112
|
Nakajima K, Yaoita Y. [Molecular mechanisms in amphibian metamorphosis]. TANPAKUSHITSU KAKUSAN KOSO. PROTEIN, NUCLEIC ACID, ENZYME 2005; 50:717-23. [PMID: 15926505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
|
113
|
Kindblom JM, Gevers EF, Skrtic SM, Lindberg MK, Göthe S, Törnell J, Vennström B, Ohlsson C. Increased adipogenesis in bone marrow but decreased bone mineral density in mice devoid of thyroid hormone receptors. Bone 2005; 36:607-16. [PMID: 15780976 DOI: 10.1016/j.bone.2005.01.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2004] [Revised: 12/06/2004] [Accepted: 01/11/2005] [Indexed: 01/02/2023]
Abstract
Mice deficient for all known thyroid hormone receptors, TRalpha1-/-beta-/- mice, display a clear skeletal phenotype characterized by growth retardation, delayed maturation of long bones and decreased trabecular and total bone mineral density (BMD; -14.6 +/- 2.8%, -14.4 +/- 1.5%). The aim of the present study was to investigate the molecular mechanisms behind the skeletal phenotype in TRalpha1-/-beta-/- mice. Global gene expression analysis was performed on total vertebrae from wild-type (WT) and TRalpha1-/-beta-/- mice using DNA microarray and the results were verified by real-time PCR. The mRNA levels of six genes (AdipoQ, Adipsin, Fat-Specific Protein 27 (FSP 27), lipoprotein lipase (LPL), retinol-binding protein (RBP) and phosphoenolpyruvate carboxykinase (PEPCK)) expressed by mature adipocytes were increased in TRalpha1-/-beta-/- compared with WT mice. An increased amount of fat (225% over WT) due to an increased number but unchanged mean size of adipocytes in the bone marrow of TRalpha1-/-beta-/- mice was revealed. Interestingly, the mRNA levels of the key regulator of osteoclastogenesis, receptor activator of NF-varkappab ligand (RANKL), were dramatically decreased in TRalpha1-/-beta-/- mice. In conclusion, TRalpha1-/-beta-/- mice demonstrated increased expression of adipocyte specific genes and an increased amount of bone marrow fat. Thus, these mice have increased adipogenesis in bone marrow associated with decreased trabecular bone mineral density (BMD). One may speculate that these effects either could be caused by an imbalance in the differentiation of the osteoblast and the adipocyte lineages at the expense of osteoblastogenesis, or by independent effects on the regulation of both osteoblastogenesis and adipogenesis.
Collapse
|
114
|
Rothenberg EV. Immunology. Thymic regulation--hidden in plain sight. Science 2005; 307:858-9. [PMID: 15709236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
MESH Headings
- Animals
- Cell Differentiation
- Cell Lineage
- Gene Expression
- Gene Expression Regulation
- Gene Rearrangement, T-Lymphocyte
- Genes, T-Cell Receptor
- Lymph Nodes/cytology
- Lymph Nodes/embryology
- Lymphotoxin-alpha/biosynthesis
- Lymphotoxin-alpha/genetics
- Lymphotoxin-alpha/physiology
- Mice
- Nuclear Receptor Subfamily 1, Group F, Member 3
- Phenotype
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, gamma-delta/biosynthesis
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/physiology
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/physiology
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/physiology
- Thymus Gland/cytology
- Thymus Gland/immunology
Collapse
|
115
|
Abstract
Repression by nuclear hormone receptors (NHRs) plays an important role in development, immune response and cellular function. We review mechanisms of how NHRs act as repressors of gene transcription either by direct contact with basal transcription factors or through recruitment of cofactors and enzymic activities that modulate chromatin accessibility. We describe also the role and biochemical mechanism of the cognate hormone that switches a NHR from a transcriptional silencer into an activator. This includes data from crystal structure, functional receptor domain analyses and the role of co-repressors in chromatin modification and remodelling. Furthermore, the comparison of negative response elements with classical response elements unravels the role of co-repressors in this context. We also describe the inhibition of the nuclear factor kappaB and Jun/Fos pathway by NHRs, as well as the molecular mechanism of anti-hormone therapies. Anti-hormones are commonly used in breast and prostate cancer therapy to inhibit cancer proliferation through repression of the oestrogen or androgen receptor, respectively. Here we provide a comprehensive overview of the various mechanism of NHR repression.
Collapse
|
116
|
Freitas FRS, Capelo LP, O'Shea PJ, Jorgetti V, Moriscot AS, Scanlan TS, Williams GR, Zorn TMT, Gouveia CHA. The thyroid hormone receptor beta-specific agonist GC-1 selectively affects the bone development of hypothyroid rats. J Bone Miner Res 2005; 20:294-304. [PMID: 15647824 DOI: 10.1359/jbmr.041116] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2004] [Revised: 08/16/2004] [Accepted: 09/14/2004] [Indexed: 12/14/2022]
Abstract
UNLABELLED We investigated the effects of GC-1, a TRbeta-selective thyromimetic, on bone development of hypothyroid rats. Whereas T3 reverted the IGF-I deficiency and the skeletal defects caused by hypothyroidism, GC-1 had no effect on serum IGF-I or on IGF-I protein expression in the epiphyseal growth plate of the femur, but induced selective effects on bone development. Our findings indicate that T3 exerts some essential effects on bone development that are mediated by TRbeta1. INTRODUCTION We investigated the role of the thyroid hormone receptor beta1 (TRbeta1) on skeletal development of rats using the TRbeta-selective agonist GC-1. MATERIALS AND METHODS Twenty-one-day-old female rats (n = 6/group) were rendered hypothyroid (Hypo) and treated for 5 weeks with 0.3 ug/100 g BW/day of T3 (1xT3), 5xT3, or equimolar doses of GC-1 (1xGC-1 and 5xGC-1). Serum triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), and insulin-like growth factor (IGF)-I concentrations were determined by radioimmunoassay (RIA). BMD and longitudinal bone growth were determined by DXA. Trabecular bone histomorphometry and epiphyseal growth plate (EGP) morphometry were performed in the distal femur. Expressions of IGF-I protein and of collagen II and X mRNA were evaluated by immunohistochemistry and in situ hybridization, respectively. To determine hormonal effects on ossification, skeletal preparations of hypothyroid-, 5xGC-1-, and 5xT3-treated neonatal rats were compared. RESULTS Hypothyroidism impaired longitudinal body growth and BMD gain, delayed ossification, reduced the number of hypertrophic chondrocytes (HCs; 72% versus Euthyroid [Eut] rats; p < 0.001), and resulted in disorganized columns of EGP chondrocytes. Serum IGF-I was 67% reduced versus Eut rats (p < 0.001), and the expression of IGF-I protein and collagen II and X mRNA were undetectable in the EGP of Hypo rats. T3 completely or partially normalized all these parameters. In contrast, GC-1 did not influence serum concentrations or EGP expression of IGF-I, failed to reverse the disorganization of proliferating chondrocyte columns, and barely affected longitudinal growth. Nevertheless, GC-1 induced ossification, HC differentiation, and collagen II and X mRNA expression and increased EGP thickness to Eut values. GC-1-treated rats had higher BMD gain in the total tibia, total femur, and in the femoral diaphysis than Hypo animals (p < 0.05). These changes were associated with increased trabecular volume (48%, p < 0.01), mineralization apposition rate (2.3-fold, p < 0.05), mineralizing surface (4.3-fold, p < 0.01), and bone formation rate (10-fold, p < 0.01). CONCLUSIONS Treatment of hypothyroid rats with the TRbeta-specific agonist GC-1 partially reverts the skeletal development and maturation defects resultant of hypothyroidism. This finding suggests that TRbeta1 has an important role in bone development.
Collapse
|
117
|
Shah OJ, Hunter T. Tuberous sclerosis and insulin resistance. Unlikely bedfellows reveal a TORrid affair. Cell Cycle 2005; 4:46-51. [PMID: 15611656 DOI: 10.4161/cc.4.1.1343] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
The TSC1-TSC2 tumor suppressor complex serves as an interface between insulin and nutrient signaling pathways and the cell growth machinery. Recent work has indicated that the TSC1-TSC2 complex plays a role in the pathobiology of a number of tumor predisposition syndromes, including tuberous sclerosis (TSC1/2), Peutz-Jeghers syndrome (LKB1), and Cowden's syndrome (PTEN), in which the TSC/Rheb/mTOR axis is inappropriately active secondary to loss of tumor suppressor function. Recent work has demonstrated that TSC deficiency imposes a negative autoregulatory loop that suppresses insulin signaling at the post-receptor level, effectively resulting in cell autonomous insulin resistance. Exploitation of this insulin signaling deficiency may hold promise among tailored clinical therapies designed to manage tuberous sclerosis.
Collapse
MESH Headings
- Animals
- Apoptosis/genetics
- Apoptosis/physiology
- Gene Expression Regulation
- Genetic Predisposition to Disease
- Hamartoma Syndrome, Multiple/genetics
- Hamartoma Syndrome, Multiple/physiopathology
- Humans
- Insulin Receptor Substrate Proteins
- Insulin Resistance/genetics
- Insulin Resistance/physiology
- Nuclear Receptor Subfamily 1, Group F, Member 3
- Peutz-Jeghers Syndrome/genetics
- Peutz-Jeghers Syndrome/physiopathology
- Phosphoproteins/genetics
- Phosphoproteins/physiology
- Protein Processing, Post-Translational
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/physiology
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/physiology
- Transcription, Genetic
- Tuberous Sclerosis/genetics
- Tuberous Sclerosis/physiopathology
- Tuberous Sclerosis Complex 1 Protein
- Tuberous Sclerosis Complex 2 Protein
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/physiology
Collapse
|
118
|
Silva-Santos B, Pennington DJ, Hayday AC. Lymphotoxin-mediated regulation of gammadelta cell differentiation by alphabeta T cell progenitors. Science 2004; 307:925-8. [PMID: 15591166 DOI: 10.1126/science.1103978] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The thymus gives rise to two T cell lineages, alphabeta and gammadelta, that are thought to develop independently of one another. Hence, double positive (DP) thymocytes expressing CD4 and CD8 coreceptors are usually viewed simply as progenitors of CD4+ and CD8+ alphabeta T cells. Instead we report that DP cells regulate the differentiation of early thymocyte progenitors and gammadelta cells, by a mechanism dependent on the transcription factor RORgt, and the lymphotoxin (LT) beta receptor (LTbetaR). This finding provokes a revised view of the thymus, in which lymphoid tissue induction-type processes coordinate the developmental and functional integration of the two T cell lineages.
Collapse
MESH Headings
- Animals
- Cell Differentiation
- Cell Lineage
- Gene Expression
- Genes, T-Cell Receptor
- Ligands
- Lymphocyte Activation
- Lymphotoxin beta Receptor
- Lymphotoxin-alpha/biosynthesis
- Lymphotoxin-alpha/genetics
- Lymphotoxin-alpha/physiology
- Membrane Proteins/genetics
- Mice
- Mice, Inbred C57BL
- Nuclear Receptor Subfamily 1, Group F, Member 3
- Phenotype
- Receptors, Antigen, T-Cell, alpha-beta/biosynthesis
- Receptors, Antigen, T-Cell, gamma-delta/biosynthesis
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/physiology
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/physiology
- Receptors, Tumor Necrosis Factor/genetics
- Receptors, Tumor Necrosis Factor/physiology
- Reverse Transcriptase Polymerase Chain Reaction
- Signal Transduction
- T-Lymphocyte Subsets/cytology
- T-Lymphocyte Subsets/immunology
- T-Lymphocyte Subsets/physiology
- Thymus Gland/cytology
- Thymus Gland/immunology
- Transcription Factors/biosynthesis
- Transcription Factors/genetics
- Tumor Necrosis Factor Ligand Superfamily Member 14
- Tumor Necrosis Factor-alpha/genetics
- Up-Regulation
Collapse
|
119
|
Djabali K, Zlotogorski A, Metzker A, Ben-Amitai D, Christiano AM. Interaction of hairless and thyroid hormone receptor is not involved in the pathogenesis of atrichia with papular lesions. Exp Dermatol 2004; 13:251-6. [PMID: 15086341 DOI: 10.1111/j.0906-6705.2004.00174.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Atrichia with papular lesions (APL) (MIM 209 500) is a rare autosomal recessive disease characterized by early onset of atrichia, followed by a papular eruption within the first years of life. Recent studies demonstrating linkage to chromosome 8p21 and further mutation detection in the hairless gene (HR) have established the molecular basis of APL. This study describes the case of a 16-year-old female with APL due to a missense mutation, D1012N, in the hr-thyroid hormone receptor interacting domain 2 (TRID2) of the HR. Using functional and biochemical analysis, it was determined that this mutation does not significantly affect hr-thyroid hormone receptor interaction. This result suggests that the TRID2 domain either is dispensable in the hr-TR interaction or is not involved in the pathogenesis of APL.
Collapse
|
120
|
Collins LL, Lee YF, Heinlein CA, Liu NC, Chen YT, Shyr CR, Meshul CK, Uno H, Platt KA, Chang C. Growth retardation and abnormal maternal behavior in mice lacking testicular orphan nuclear receptor 4. Proc Natl Acad Sci U S A 2004; 101:15058-63. [PMID: 15477591 PMCID: PMC524065 DOI: 10.1073/pnas.0405700101] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Testicular orphan nuclear receptor 4 (TR4) is a member of the nuclear receptor superfamily for which a ligand has not yet been found. In vitro data obtained from various cell lines suggest that TR4 functions as a master regulator to modulate many signaling pathways, yet the in vivo physiological roles of TR4 remain unclear. Here, we report the generation of mice lacking TR4 by means of targeted gene disruption (TR4(-/-)). The number of TR4(-/-) pups generated by the mating of TR4(+/-) mice is well under that predicted by the normal Mendelian ratio, and TR4(-/-) mice demonstrate high rates of early postnatal mortality, as well as significant growth retardation. Additionally, TR4(-/-) females show defects in reproduction and maternal behavior, with pups of TR4(-/-) dams dying soon after birth with no indication of milk intake. These results provide in vivo evidence that TR4 plays important roles in growth, embryonic and early postnatal pup survival, female reproductive function, and maternal behavior.
Collapse
MESH Headings
- Animals
- Base Sequence
- DNA, Complementary/genetics
- Eye/pathology
- Female
- Fetal Death/genetics
- Fetal Death/metabolism
- Growth Disorders/genetics
- Growth Disorders/metabolism
- Growth Hormone/blood
- Infertility, Female/genetics
- Infertility, Female/metabolism
- Insulin-Like Growth Factor I/metabolism
- Male
- Maternal Behavior/physiology
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Pregnancy
- Receptors, Steroid/deficiency
- Receptors, Steroid/genetics
- Receptors, Steroid/physiology
- Receptors, Thyroid Hormone/deficiency
- Receptors, Thyroid Hormone/genetics
- Receptors, Thyroid Hormone/physiology
- Testis/metabolism
Collapse
|
121
|
Berkenstam A, Färnegårdh M, Gustafsson JA. Convergence of lipid homeostasis through liver X and thyroid hormone receptors. Mech Ageing Dev 2004; 125:707-17. [PMID: 15541766 DOI: 10.1016/j.mad.2004.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Members of the nuclear receptor gene family act as biological rheostats to maintain metabolic homeostasis in response to endocrine and nutritional changes. The liver X (LXR) and thyroid hormone (TR) receptors have been shown to regulate overlapping but distinct metabolic pathways important for overall lipid homeostasis. Dyslipidemia is one out of four key determinants for cardiovascular risk and both LXRs and TRs may provide attractive targets for intervention of cardiovascular disease. In this review we will compare the two receptor systems to highlight similarities and differences in structure and function with implications for development of novel treatments for dyslipidemia and atherosclerosis.
Collapse
|
122
|
Köhrle J. Guard your master: thyroid hormone receptors protect their gland of origin from thyroid cancer. Endocrinology 2004; 145:4427-9. [PMID: 15375080 DOI: 10.1210/en.2004-0928] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
123
|
Zoeller RT, Rovet J. Timing of thyroid hormone action in the developing brain: clinical observations and experimental findings. J Neuroendocrinol 2004; 16:809-18. [PMID: 15500540 DOI: 10.1111/j.1365-2826.2004.01243.x] [Citation(s) in RCA: 396] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Abstract The original concept of the critical period of thyroid hormone (TH) action on brain development was proposed to identify the postnatal period during which TH supplement must be provided to a child with congenital hypothyroidism to prevent mental retardation. As neuropsychological tools have become more sensitive, it has become apparent that even mild TH insufficiency in humans can produce measurable deficits in very specific neuropsychological functions, and that the specific consequences of TH deficiency depends on the precise developmental timing of the deficiency. Models of maternal hypothyroidism, hypothyroxinaemia and congenital hyperthyroidism have provided these insights. If the TH deficiency occurs early in pregnancy, the offspring display problems in visual attention, visual processing (i.e. acuity and strabismus) and gross motor skills. If it occurs later in pregnancy, children are at additional risk of subnormal visual (i.e. contrast sensitivity) and visuospatial skills, as well as slower response speeds and fine motor deficits. Finally, if TH insufficiency occurs after birth, language and memory skills are most predominantly affected. Although the experimental literature lags behind clinical studies in providing a mechanistic explanation for each of these observations, recent studies confirm that the specific action of TH on brain development depends upon developmental timing, and studies informing us about molecular mechanisms of TH action are generating hypotheses concerning possible mechanisms to account for these pleiotropic actions.
Collapse
|
124
|
Kim SW, Hong SJ, Kim KM, Ho SC, So EC, Harney JW, Larsen PR. A novel cell type-specific mechanism for thyroid hormone-dependent negative regulation of the human type 1 deiodinase gene. Mol Endocrinol 2004; 18:2924-36. [PMID: 15331760 DOI: 10.1210/me.2004-0255] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
We have identified a cell type-specific, negative thyroid hormone-responsive element in the human type 1 iodothyronine deiodinase (hdio1) gene. This fragment, termed a JEG response element, bound tightly to a JEG-cell nuclear protein [JEG cell-specific transcription factor (JTF)] also present in placenta but not in COS-7, HeLa, or human embryonic kidney-293 cells. In JEG-3 cells, three copies of the JEG response element conferred a more than 40-fold transcriptional stimulation to the heterologous rat GH promoter which was further increased 2-fold by apo-thyroid hormone receptor (TR) and reduced 3-fold by T(3). Dimethyl sulfide footprinting showed overlapping contact sites for the high-affinity interaction of JTF and low-affinity binding of TR-retinoid X receptor. Expression of the same construct was unaffected by TR or T(3) in COS cells, indicating JTF was required for negative regulation by T(3)-TR. Mutations of the critical thyroid hormone responsive element binding P box amino acids EG to GS in TRalpha1 or TRbeta2 eliminated the apo-TR and T(3)-TR effects. These studies identify a novel mechanism for cell type-specific, promoter-independent negative regulation by T(3).
Collapse
|
125
|
Mu X, Lee YF, Liu NC, Chen YT, Kim E, Shyr CR, Chang C. Targeted inactivation of testicular nuclear orphan receptor 4 delays and disrupts late meiotic prophase and subsequent meiotic divisions of spermatogenesis. Mol Cell Biol 2004; 24:5887-99. [PMID: 15199144 PMCID: PMC480911 DOI: 10.1128/mcb.24.13.5887-5899.2004] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Testicular orphan nuclear receptor 4 (TR4) is specifically and stage-dependently expressed in late-stage pachytene spermatocytes and round spermatids. In the developing mouse testis, the highest expression of TR4 can be detected at postnatal days 16 to 21 when the first wave of spermatogenesis progresses to late meiotic prophase. Using a knockout strategy to delete TR4 in mice, we found that sperm production in TR4(-/-) mice is reduced. The comparison of testes from developing TR4(+/+) and TR4(-/-) mice shows that spermatogenesis in TR4(-/-) mice is delayed. Analysis of the first wave of spermatogenesis shows that the delay can be due to delay and disruption of spermatogenesis at the end of late meiotic prophase and subsequent meiotic divisions. Seminiferous tubule staging shows that stages X to XII, where late meiotic prophase and meiotic divisions take place, are delayed and disrupted in TR4(-/-) mice. Histological examination of testis sections from TR4(-/-) mice shows degenerated primary spermatocytes and some necrotic tubules. Testis-specific gene analyses show that the expression of sperm 1 and cyclin A1, which are genes expressed at the end of meiotic prophase, was delayed and decreased in TR4(-/-) mouse testes. Taken together, results from TR4(+/+) and TR4(-/-) mice indicate that TR4 is essential for normal spermatogenesis in mice.
Collapse
|