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Nappi A, Miro C, Pezone A, Tramontano A, Di Cicco E, Sagliocchi S, Cicatiello AG, Murolo M, Torabinejad S, Abbotto E, Caiazzo G, Raia M, Stornaiuolo M, Antonini D, Fabbrocini G, Salvatore D, Avvedimento VE, Dentice M. Loss of p53 activates thyroid hormone via type 2 deiodinase and enhances DNA damage. Nat Commun 2023; 14:1244. [PMID: 36871014 PMCID: PMC9985592 DOI: 10.1038/s41467-023-36755-y] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Accepted: 02/15/2023] [Indexed: 03/06/2023] Open
Abstract
The Thyroid Hormone (TH) activating enzyme, type 2 Deiodinase (D2), is functionally required to elevate the TH concentration during cancer progression to advanced stages. However, the mechanisms regulating D2 expression in cancer still remain poorly understood. Here, we show that the cell stress sensor and tumor suppressor p53 silences D2 expression, thereby lowering the intracellular THs availability. Conversely, even partial loss of p53 elevates D2/TH resulting in stimulation and increased fitness of tumor cells by boosting a significant transcriptional program leading to modulation of genes involved in DNA damage and repair and redox signaling. In vivo genetic deletion of D2 significantly reduces cancer progression and suggests that targeting THs may represent a general tool reducing invasiveness in p53-mutated neoplasms.
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Affiliation(s)
- Annarita Nappi
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | - Caterina Miro
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | - Antonio Pezone
- Department of Biology, University of Naples "Federico II", 80126, Naples, Italy
| | - Alfonso Tramontano
- Department of Precision Medicine, University of Campania "L. Vanvitelli", 80138, Naples, Italy
| | - Emery Di Cicco
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | - Serena Sagliocchi
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | | | - Melania Murolo
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | - Sepehr Torabinejad
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | - Elena Abbotto
- Department of Experimental Medicine, University of Genoa, 16132, Genoa, Italy
| | - Giuseppina Caiazzo
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | - Maddalena Raia
- CEINGE, Biotecnologie Avanzate S.c.a.r.l., 80131, Naples, Italy
| | - Mariano Stornaiuolo
- Department of Pharmacy, University of Naples "Federico II", 80149, Naples, Italy
| | - Dario Antonini
- Department of Biology, University of Naples "Federico II", 80126, Naples, Italy
| | - Gabriella Fabbrocini
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy
| | - Domenico Salvatore
- CEINGE, Biotecnologie Avanzate S.c.a.r.l., 80131, Naples, Italy.,Department of Public Health, University of Naples "Federico II", 80131, Naples, Italy
| | - Vittorio Enrico Avvedimento
- Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", 80131, Naples, Italy
| | - Monica Dentice
- Department of Clinical Medicine and Surgery, University of Naples "Federico II", 80131, Naples, Italy. .,CEINGE, Biotecnologie Avanzate S.c.a.r.l., 80131, Naples, Italy.
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Mulligan MK, Kleiman JE, Caldemeyer AC, Harding JCS, Pasternak JA. Porcine reproductive and respiratory virus 2 infection of the fetus results in multi-organ cell cycle suppression. Vet Res 2022; 53:13. [PMID: 35189966 PMCID: PMC8860275 DOI: 10.1186/s13567-022-01030-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Accepted: 02/02/2022] [Indexed: 11/10/2022] Open
Abstract
AbstractPorcine reproductive and respiratory syndrome virus (PRRSV) infection during late gestation negatively affects fetal development. The objective of this study was to identify the fetal organs most severely impacted following infection, and evaluate the relationship between this response and fetal phenotypes. RNA was extracted from fetal heart, liver, lung, thymus, kidney, spleen, and loin muscle, collected following late gestation viral challenge of pregnant gilts. Initially, gene expression for three cell cycle promoters (CDK1, CDK2, CDK4) and one inhibitor (CDKN1A) were evaluated in biologically extreme phenotypic subsets including gestational age-matched controls (CON), uninfected (UNIF), high-viral load viable (HV-VIA), and high-viral load meconium-stained (HV-MEC) fetuses. There were no differences between CON and UNIF groups for any gene, indicating no impact of maternal infection alone. Relative to CON, high-viral load (HV-VIA, HV-MEC) fetuses showed significant downregulation of at least one CDK gene in all tissues except liver, while CDKN1A was upregulated in all tissues except muscle, with the heart and kidney most severely impacted. Subsequent evaluation of additional genes known to be upregulated following activation of P53 or TGFb/SMAD signaling cascades indicated neither pathway was responsible for the observed increase in CDKN1A. Finally, analysis of heart and kidney from a larger unselected population of infected fetuses from the same animal study showed that serum thyroxin and viral load were highly correlated with the expression of CDKN1A in both tissues. Collectively these results demonstrate the widespread suppression in cell division across all tissues in PRRSV infected fetuses and indicate a non-canonical regulatory mechanism.
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Nappi A, Murolo M, Sagliocchi S, Miro C, Cicatiello AG, Di Cicco E, Di Paola R, Raia M, D’Esposito L, Stornaiuolo M, Dentice M. Selective Inhibition of Genomic and Non-Genomic Effects of Thyroid Hormone Regulates Muscle Cell Differentiation and Metabolic Behavior. Int J Mol Sci 2021; 22:7175. [PMID: 34281225 PMCID: PMC8269436 DOI: 10.3390/ijms22137175] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 06/28/2021] [Accepted: 06/28/2021] [Indexed: 02/08/2023] Open
Abstract
Thyroid hormones (THs) are key regulators of different biological processes. Their action involves genomic and non-genomic mechanisms, which together mediate the final effects of TH in target tissues. However, the proportion of the two processes and their contribution to the TH-mediated effects are still poorly understood. Skeletal muscle is a classical target tissue for TH, which regulates muscle strength and contraction, as well as energetic metabolism of myofibers. Here we address the different contribution of genomic and non-genomic action of TH in skeletal muscle cells by specifically silencing the deiodinase Dio2 or the β3-Integrin expression via CRISPR/Cas9 technology. We found that myoblast proliferation is inversely regulated by integrin signal and the D2-dependent TH activation. Similarly, inhibition of the nuclear receptor action reduced myoblast proliferation, confirming that genomic action of TH attenuates proliferative rates. Contrarily, genomic and non-genomic signals promote muscle differentiation and the regulation of the redox state. Taken together, our data reveal that integration of genomic and non-genomic signal pathways finely regulates skeletal muscle physiology. These findings not only contribute to the understanding of the mechanisms involved in TH modulation of muscle physiology but also add insight into the interplay between different mechanisms of action of TH in muscle cells.
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Affiliation(s)
- Annarita Nappi
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
| | - Melania Murolo
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
| | - Serena Sagliocchi
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
| | - Caterina Miro
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
| | - Annunziata Gaetana Cicatiello
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
| | - Emery Di Cicco
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
| | - Rossella Di Paola
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
| | - Maddalena Raia
- CEINGE–Biotecnologie Avanzate Scarl, 80131 Naples, Italy;
| | - Lucia D’Esposito
- Centro Servizi Veterinari, University of Naples Federico II, 80131 Naples, Italy;
| | - Mariano Stornaiuolo
- Department of Pharmacy, University of Naples Federico II, 80131 Naples, Italy;
| | - Monica Dentice
- Department of Clinical Medicine and Surgery, University of Naples Federico II, 80131 Naples, Italy; (A.N.); (M.M.); (S.S.); (C.M.); (A.G.C.); (E.D.C.); (R.D.P.)
- CEINGE–Biotecnologie Avanzate Scarl, 80131 Naples, Italy;
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Zhao L, Wang X, Pomlok K, Liao H, Yang G, Yang X, Chen YG. DDB1 promotes the proliferation and hypertrophy of chondrocytes during mouse skeleton development. Dev Biol 2020; 465:100-107. [PMID: 32479761 DOI: 10.1016/j.ydbio.2020.05.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2019] [Revised: 05/17/2020] [Accepted: 05/20/2020] [Indexed: 10/24/2022]
Abstract
The proliferation and hypertrophy of chondrocytes play important roles in endochondral ossification, which is tightly regulated during skeleton development. However, the regulation mechanism remains largely unknown. Here we show that DDB1 (Damaged DNA Binding Protein 1) has a critical function in the development of growth plates. Using chondrocyte-specific DDB1 knockout mice, we found that DDB1 deletion in chondrocytes results in dwarfism due to the aberrant skeleton development. The structure of growth plate in tibia becomes disordered at P21, not in femur. But at P70, the changes are severer in femur than tibia. Chondrocyte proliferation and differentiation are attenuated and asynchronous in both tibia and femur at P7 and P21. Furthermore, DDB1 deficiency induces p27 upregulation and subsequent cell cycle arrest in primary chondrocytes. Therefore, our data reveal that DDB1 is essential for the skeleton development by controlling chondrocyte proliferation and differentiation.
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Affiliation(s)
- Lianzheng Zhao
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaodan Wang
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Kumpanat Pomlok
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Hongwei Liao
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Guan Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, 102206, China
| | - Xiao Yang
- State Key Laboratory of Proteomics, Beijing Proteome Research Center, National Center for Protein Sciences, Beijing Institute of Lifeomics, Beijing, 102206, China
| | - Ye-Guang Chen
- The State Key Laboratory of Membrane Biology, Tsinghua-Peking Center for Life Sciences, School of Life Sciences, Tsinghua University, Beijing, 100084, China.
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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.
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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
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Yang WR, Zhu FW, Zhang JJ, Wang Y, Zhang JH, Lu C, Wang XZ. PI3K/Akt Activated by GPR30 and Src Regulates 17β-Estradiol-Induced Cultured Immature Boar Sertoli Cells Proliferation. Reprod Sci 2016; 24:57-66. [DOI: 10.1177/1933719116649696] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Affiliation(s)
- Wei-Rong Yang
- College of Animal Science and Technology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Forage & Herbivore, Chongqing, China
| | - Feng-Wei Zhu
- College of Animal Science and Technology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Forage & Herbivore, Chongqing, China
| | - Jiao-Jiao Zhang
- College of Animal Science and Technology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Forage & Herbivore, Chongqing, China
| | - Yi Wang
- College of Animal Science and Technology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Forage & Herbivore, Chongqing, China
| | - Jia-Hua Zhang
- College of Animal Science and Technology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Forage & Herbivore, Chongqing, China
| | - Cheng Lu
- State Key Laboratory of Silkworm Genome Biology, Southwest University, Chongqing, China
- Key Laboratory for Sericulture Functional Genomics and Biotechnology of Agricultural Ministry, Southwest University, Chongqing, China
| | - Xian-Zhong Wang
- College of Animal Science and Technology, Southwest University, Chongqing, China
- Chongqing Key Laboratory of Forage & Herbivore, Chongqing, China
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Boruah P, Baruah AJ, Hajong R, Nath CK, Barman B, Chutia H, Sarma K. A Study to Assess the Validity of Estimation of Serum Ostase Level in Hyperthyroid and Hypothyroid Cases. J Clin Diagn Res 2016; 10:BC08-BC11. [PMID: 27790421 PMCID: PMC5071921 DOI: 10.7860/jcdr/2016/19750.8441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2016] [Accepted: 06/15/2016] [Indexed: 11/24/2022]
Abstract
INTRODUCTION One of the more specific assessments of the metabolic status of bone in normal and in disease conditions is the measurement of bone specific alkaline phosphatase or ostase. The measurement of serum ostase has several advantages over the measurements of other bone parameter. Because of its relatively long half-life, in-vivo (1 to 3days), it is relatively unaffected by diurnal variation. AIM To find the correlation of serum ostase level in hyper and hypothyroid cases and also to study the validity of routine estimation of serum ostase in hyper and hypothyroid cases so as to monitor the base level bone health on presentation. MATERIALS AND METHODS Serum ostase level was studied in 74 patients with disorder of thyroid function. Serum ostase level, Thyroid Stimulating Hormone (TSH), FT3, FT4 levels were estimated by chemiluminescent technique. The instrument used was Beckman- coulter Access 2. A total of 39 patients were hypothyroid, 31 were hyperthyroid and 4 patients had subclinical hyperthyroidism. RESULTS The serum ostase level was found to be elevated above 40 μg/L in 26 of the cases and above 16 μg/L but below 40μg/L in 5 cases of hyperthyroidism along with decrease in Bone Mineral Density (BMD). Serum ostase level was found to be directly proportional to the serum FT3 level (Normal range of serum ostase is 8-16 μg/L). CONCLUSION From this study, an inference can be drawn that a routine estimation of serum ostase level in hyperthyroid cases will help in proper monitoring of decrease bone turnover as indicated by increase serum ostase level. Besides, the estimation of serum ostase level in hyperthyroid cases it is found to be valid in this study, which can turn to be an important guiding parameter to the treating physician to formulate necessary protocols and guidelines for prophylaxis, treatment and to monitor the response to therapy in cases of reduced bone turnover related to hyperthyroid state.
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Affiliation(s)
| | - Arup Jyoti Baruah
- Associate Professor, Department of General Surgery, NEIGRIHMS, Shillong, Meghalaya, India
| | - Ranendra Hajong
- Associate Professor, Department of General Surgery, NEIGRIHMS, Shillong, Meghalaya, India
| | - Chandan Kumar Nath
- Assistant Professor, Department of Biochemistry, NEIGRIHMS, Shillong, Meghalaya, India
| | - Bhupen Barman
- Assistant Professor, Department of General Medicine, NEIGRIHMS, Shillong, Meghalaya, India
| | - Happy Chutia
- Assistant Professor, Department of Biochemistry, NEIGRIHMS, Shillong, Meghalaya, India
| | - Kalyan Sarma
- PGT, Department of Radiology, NEIGRIHMS, Shillong, Meghalaya, India
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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.
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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
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Abstract
The regulation of organ size is essential to human health and has fascinated biologists for centuries. Key to the growth process is the ability of most organs to integrate organ-extrinsic cues (eg, nutritional status, inflammatory processes) with organ-intrinsic information (eg, genetic programs, local signals) into a growth response that adapts to changing environmental conditions and ensures that the size of an organ is coordinated with the rest of the body. Paired organs such as the vertebrate limbs and the long bones within them are excellent models for studying this type of regulation because it is possible to manipulate one member of the pair and leave the other as an internal control. During development, growth plates at the end of each long bone produce a transient cartilage model that is progressively replaced by bone. Here, we review how proliferation and differentiation of cells within each growth plate are tightly controlled mainly by growth plate-intrinsic mechanisms that are additionally modulated by extrinsic signals. We also discuss the involvement of several signaling hubs in the integration and modulation of growth-related signals and how they could confer remarkable plasticity to the growth plate. Indeed, long bones have a significant ability for "catch-up growth" to attain normal size after a transient growth delay. We propose that the characterization of catch-up growth, in light of recent advances in physiology and cell biology, will provide long sought clues into the molecular mechanisms that underlie organ growth regulation. Importantly, catch-up growth early in life is commonly associated with metabolic disorders in adulthood, and this association is not completely understood. Further elucidation of the molecules and cellular interactions that influence organ size coordination should allow development of novel therapies for human growth disorders that are noninvasive and have minimal side effects.
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Affiliation(s)
- Alberto Roselló-Díez
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065
| | - Alexandra L Joyner
- Developmental Biology Program, Sloan Kettering Institute, New York, New York 10065
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Yang WR, Wang Y, Wang Y, Zhang JJ, Zhang JH, Lu C, Wang XZ. mTOR is involved in 17β-estradiol-induced, cultured immature boar Sertoli cell proliferation via regulating the expression of SKP2, CCND1, and CCNE1. Mol Reprod Dev 2015; 82:305-14. [PMID: 25739982 DOI: 10.1002/mrd.22473] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Accepted: 02/12/2015] [Indexed: 12/25/2022]
Abstract
Mammalian target of rapamycin (mTOR) is known to be involved in mammalian cell proliferation, while S-phase kinase-associated protein 2 (SKP2) plays a vital role in the cell cycle. Within the testis, estrogen also plays an important role in Sertoli cell proliferation, although it is not clear how. The present study asked if mTOR is involved in 17β-estradiol-dependent Sertoli cell proliferation. We specifically assessed if extracellular signal-regulated kinase 1/2 (ERK1/2) and/or phosphoinositide 3-kinase/protein kinase B (PI3K/AKT) exert convergent effects toward the activation of mTOR signaling, and if this signaling regulates the expression of SKP2 through retinoblastoma (RB) and early mitotic inhibitor 1 (EMI1) protein and on CCNE1 and CCND1 mRNA levels. Treatment with 17β-estradiol for 15-90 min activated mTOR, with mTOR phosphorylation peaking after 30 min. U0126 (5 μM), a specific inhibitor of (MEK1/2), and 10-DEBC (2 μM), a selective inhibitor of AKT, both significantly reduced 17β-estradiol-induced phosphorylation of mTOR. Rapamycin suppressed 17β-estradiol-induced Sertoli cell proliferation, appearing to act by reducing the abundance of SKP2, CCND1, and CCNE1 mRNA as well as RB and EMI1 protein. These data indicated that 17β-estradiol enhances Sertoli cell proliferation via mTOR activation, which involves both ERK1/2 and PI3K/AKT signaling. Activated mTOR subsequently increases SKP2 mRNA and protein expression by enhancing the expression of CCND1 and CCNE1, and inhibits SKP2 protein degradation by increasing EMI1 abundance.
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Affiliation(s)
- Wei-Rong Yang
- College of Animal Science and Technology, Southwest University, Chongqing, P. R. China; Chongqing Key Laboratory of Forage and Herbivore, Southwest University, Chongqing, P. R. China
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Karl A, Olbrich N, Pfeifer C, Berner A, Zellner J, Kujat R, Angele P, Nerlich M, Mueller MB. Thyroid hormone-induced hypertrophy in mesenchymal stem cell chondrogenesis is mediated by bone morphogenetic protein-4. Tissue Eng Part A 2013; 20:178-88. [PMID: 23937304 DOI: 10.1089/ten.tea.2013.0023] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Chondrogenic differentiating mesenchymal stem cells (MSCs) express markers of hypertrophic growth plate chondrocytes. As hypertrophic cartilage undergoes ossification, this is a concern for the application of MSCs in articular cartilage tissue engineering. To identify mechanisms that elicit this phenomenon, we used an in vitro hypertrophy model of chondrifying MSCs for differential gene expression analysis and functional experiments with the focus on bone morphogenetic protein (BMP) signaling. Hypertrophy was induced in chondrogenic MSC pellet cultures by transforming growth factor β (TGFβ) and dexamethasone withdrawal and addition of triiodothyronine. Differential gene expression analysis of BMPs and their receptors was performed. Based on these results, the in vitro hypertrophy model was used to investigate the effect of recombinant BMP4 and the BMP inhibitor Noggin. The enhancement of hypertrophy could be shown clearly by an increased cell size, alkaline phosphatase activity, and collagen type X deposition. Upon induction of hypertrophy, BMP4 and the BMP receptor 1B were upregulated. Addition of BMP4 further enhanced hypertrophy in the absence, but not in the presence of TGFβ and dexamethasone. Thyroid hormone induced hypertrophy by upregulation of BMP4 and this induced enhancement of hypertrophy could be blocked by the BMP antagonist Noggin. BMP signaling is an important modulator of the late differentiation stages in MSC chondrogenesis and the thyroid hormone induces this pathway. As cartilage tissue engineering constructs will be exposed to this factor in vivo, this study provides important insight into the biology of MSC-based cartilage. Furthermore, the possibility to engineer hypertrophic cartilage may be helpful for critical bone defect repair.
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Affiliation(s)
- Alexandra Karl
- Department of Trauma Surgery, University of Regensburg Medical Center , Regensburg, Germany
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12
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Williams GR. Thyroid hormone actions in cartilage and bone. Eur Thyroid J 2013; 2:3-13. [PMID: 24783033 PMCID: PMC3821494 DOI: 10.1159/000345548] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2012] [Revised: 11/01/2012] [Indexed: 11/19/2022] Open
Abstract
Thyroid hormones exert widespread and complex actions in almost all tissues during development, throughout childhood and in adults. The skeleton is an important T3-target tissue that exemplifies these processes, and yet understanding of the specific cellular and molecular mechanisms of T3 action in bone and cartilage remains incomplete. Here, the skeleton is considered as a T3-target tissue. The actions of thyroid hormones during skeletal development and in chondrocytes and growth plate cartilage during post-natal linear growth are outlined. The physiological importance of these actions are discussed in relation to patients with autosomal dominant mutations in genes encoding the thyroid hormone receptors TRα1 and TRβ, and in mice harbouring deletions or mutations of the orthologous genes. The role of thyroid hormones and the control of T3 action in bone turnover and maintenance are also outlined, and T3 action in bone-forming osteoblasts and bone-resorbing osteoclasts discussed. The physiological and functional consequences of T3 action in bone are considered in relation to mutant mouse models and to effects on bone mineral density and fracture susceptibility in humans. Finally, new studies identifying a putative role for thyroid hormone metabolism in articular cartilage maintenance and the pathogenesis of osteoarthritis are considered. The pharmacological context of these new findings is discussed, emphasising the importance of this emerging field of study in thyroid hormone pathophysiology.
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Affiliation(s)
- Graham R. Williams
- Molecular Endocrinology Group, Department of Medicine, Imperial College London, London, UK
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13
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Smith LB, Belanger JM, Oberbauer AM. Fibroblast growth factor receptor 3 effects on proliferation and telomerase activity in sheep growth plate chondrocytes. J Anim Sci Biotechnol 2012; 3:39. [PMID: 23216972 PMCID: PMC3541258 DOI: 10.1186/2049-1891-3-39] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2012] [Accepted: 12/03/2012] [Indexed: 11/10/2022] Open
Abstract
UNLABELLED BACKGROUND Fibroblast growth factor receptor 3 (FGFR3) inhibits growth-plate chondrocyte proliferation and limits bone elongation. Gain-of-function FGFR3 mutations cause dwarfism, reduced telomerase activity and shorter telomeres in growth plate chondroyctes suggesting that FGFR3 reduces proliferative capacity, inhibits telomerase, and enhances senescence. Thyroid hormone (T3) plays a role in cellular maturation of growth plate chondrocytes and a known target of T3 is FGFR3. The present study addressed whether reduced FGFR3 expression enhanced telomerase activity, mRNA expression of telomerase reverse transcriptase (TERT) and RNA component of telomerase (TR), and chondrocyte proliferation, and whether the stimulation of FGFR3 by T3 evoked the opposite response. RESULTS Sheep growth-plate proliferative zone chondrocytes were cultured and transfected with siRNA to reduce FGFR3 expression; FGFR3 siRNA reduced chondrocyte FGFR3 mRNA and protein resulting in greater proliferation and increased TERT mRNA expression and telomerase activity (p < 0.05). Chondrocytes treated with T3 significantly enhanced FGFR3 mRNA and protein expression and reduced telomerase activity (p < 0.05); TERT and TR were not significantly reduced. The action of T3 at the growth plate may be partially mediated through the FGFR3 pathway. CONCLUSIONS The results suggest that FGFR3 inhibits chondrocyte proliferation by down-regulating TERT expression and reducing telomerase activity indicating an important role for telomerase in sustaining chondrocyte proliferative capacity during bone elongation.
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Affiliation(s)
- Logan B Smith
- Department of Animal Science, University of California, Davis, CA, 95616, USA.
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Wojcicka A, Bassett JHD, Williams GR. Mechanisms of action of thyroid hormones in the skeleton. Biochim Biophys Acta Gen Subj 2012; 1830:3979-86. [PMID: 22634735 DOI: 10.1016/j.bbagen.2012.05.005] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2012] [Revised: 04/19/2012] [Accepted: 05/18/2012] [Indexed: 11/25/2022]
Abstract
BACKGROUND Thyroid hormones regulate skeletal development, acquisition of peak bone mass and adult bone maintenance. Abnormal thyroid status during childhood disrupts bone maturation and linear growth, while in adulthood it results in altered bone remodeling and an increased risk of fracture SCOPE OF REVIEW This review considers the cellular effects and molecular mechanisms of thyroid hormone action in the skeleton. Human clinical and population data are discussed in relation to the skeletal phenotypes of a series of genetically modified mouse models of disrupted thyroid hormone signaling. MAJOR CONCLUSIONS Euthyroid status is essential for normal bone development and maintenance. Major thyroid hormone actions in skeletal cells are mediated by thyroid hormone receptor α (TRα) and result in anabolic responses during growth and development but catabolic effects in adulthood. These homeostatic responses to thyroid hormone are locally regulated in individual skeletal cell types by the relative activities of the type 2 and 3 iodothyronine deiodinases, which control the supply of the active thyroid hormone 3,5,3'-L-triiodothyronine (T3) to its receptor. GENERAL SIGNIFICANCE Population studies indicate that both thyroid hormone deficiency and excess are associated with an increased risk of fracture. Understanding the cellular and molecular basis of T3 action in skeletal cells will lead to the identification of new targets to regulate bone turnover and mineralization in the prevention and treatment of osteoporosis. This article is part of a Special Issue entitled Thyroid hormone signaling.
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Affiliation(s)
- Anna Wojcicka
- The Medical Centre of Postgraduate Education, Department of Biochemistry and Molecular Biology, ul.Marymoncka 99/103, 01-813 Warsaw, Poland
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15
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Simsa-Maziel S, Monsonego-Ornan E. Interleukin-1β promotes proliferation and inhibits differentiation of chondrocytes through a mechanism involving down-regulation of FGFR-3 and p21. Endocrinology 2012; 153:2296-310. [PMID: 22492305 DOI: 10.1210/en.2011-1756] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The proinflammatory cytokine IL-1β is elevated in many childhood chronic inflammatory diseases as well as obesity and can be associated with growth retardation. Here we show that IL-1β affects bone growth by directly disturbing the normal sequence of events in the growth plate, resulting in increased proliferation and widening of the proliferative zone, whereas the hypertrophic zone becomes disorganized, with impaired matrix structure and increased apoptosis and osteoclast activity. This was also evident in vitro: IL-1β increased proliferation and caused a G1-to-S phase shift in the cell cycle in ATDC5 chondrocytes, accompanied by a reduction in fibroblast growth factor receptor-3 (FGFR-3) and its downstream gene, the cell-cycle inhibitor p21 and its family member p57, whereas the cell-cycle promoter E2F-2 was increased. The reduction in FGFR-3, p21, and p57 was followed by delayed cell differentiation, manifested by decreases in proteoglycan synthesis, mineralization, alkaline phosphatase activity, and the expression of Sox9, RunX2, collagen type II, collagen type X, and other matrix proteins. Taken together, we suggest that IL-1β alters normal chondrogenesis and bone growth through a mechanism involving down-regulation of FGFR-3 and p21.
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Affiliation(s)
- Stav Simsa-Maziel
- Institute of Biochemistry and Nutrition, The Robert H. Smith Faculty of Agriculture, Food, and Environment, The Hebrew University, P.O. Box 12, Rehovot 76100, Israel
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16
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Thyroid hormone receptors, cell growth and differentiation. Biochim Biophys Acta Gen Subj 2012; 1830:3908-16. [PMID: 22484490 DOI: 10.1016/j.bbagen.2012.03.012] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2011] [Revised: 03/01/2012] [Accepted: 03/20/2012] [Indexed: 12/11/2022]
Abstract
BACKGROUND Tissue homeostasis depends on the balance between cell proliferation and differentiation. Thyroid hormones (THs), through binding to their nuclear receptors, can regulate the expression of many genes involved in cell cycle control and cellular differentiation. This can occur by direct transcriptional regulation or by modulation of the activity of different signaling pathways. SCOPE OF REVIEW In this review we will summarize the role of the different receptor isoforms in growth and maturation of selected tissues and organs. We will focus on mammalian tissues, and therefore we will not address the fundamental role of the THs during amphibian metamorphosis. MAJOR CONCLUSIONS The actions of THs are highly pleiotropic, affecting many tissues at different developmental stages. As a consequence, their effects on proliferation and differentiation are highly heterogeneous depending on the cell type, the cellular context, and the developmental or transformation status. Both during development and in the adult, stem cells are essential for proper organ formation, maintenance and regeneration. Recent evidence suggests that some of the actions of the thyroid hormone receptors could be secondary to regulation of stem/progenitor cell function. Here we will also include the latest knowledge on the role of these receptors in proliferation and differentiation of embryonic and adult stem cells. GENERAL SIGNIFICANCE The thyroid hormone receptors are potent regulators of proliferation and differentiation of many cell types. This can explain the important role of the thyroid hormones and their receptors in key processes such as growth, development, tissue homeostasis or cancer. This article is part of a Special Issue entitled Thyroid hormone signalling.
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Dentice M. Hedgehog-mediated regulation of thyroid hormone action through iodothyronine deiodinases. Expert Opin Ther Targets 2011; 15:493-504. [DOI: 10.1517/14728222.2011.553607] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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18
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Thyroid and bone. Arch Biochem Biophys 2010; 503:129-36. [DOI: 10.1016/j.abb.2010.06.021] [Citation(s) in RCA: 108] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2010] [Revised: 06/15/2010] [Accepted: 06/18/2010] [Indexed: 11/20/2022]
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Owen HC, Ahmed SF, Farquharson C. Chondrocyte p21(WAF1/CIP1) expression is increased by dexamethasone but does not contribute to dexamethasone-induced growth retardation in vivo. Calcif Tissue Int 2009; 85:326-34. [PMID: 19727539 DOI: 10.1007/s00223-009-9276-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2009] [Accepted: 07/29/2009] [Indexed: 01/03/2023]
Abstract
It has been shown that cell cycle genes play an important role in the coordination of chondrocyte proliferation and differentiation. The inhibitory effects of glucocorticoids (GCs) on chondrocyte proliferation are consistent with GCs disrupting cell cycle progression and promoting cell cycle exit. Cyclin-dependent kinase inhibitors (CDKIs) force cells to exit the cell cycle and differentiate, and studies have shown that expression of the CDKI p21(CIP1/WAF1) is increased in terminally differentiated cells. In this study, p21 mRNA and protein expression was increased during chondrocyte differentiation and after exposure to dexamethasone (Dex, 10(-6 )M) in murine chondrogenic ATDC5 cells. In 4-week-old mice lacking a functional p21 gene, Dex caused a reduction in body weight compared to saline control null mice, but this was consistent with the reduction in body weight observed in Dex-treated wild-type littermates. In addition, p21 ablation had no effect on the reduction in width of the growth plate or reduced mineral apposition rate in Dex-treated mice. However, an alteration in growth rate and epiphyseal structure is evident when comparing p21(-/-) and wild-type mice. These findings suggest that p21 does not directly contribute to GC-induced growth retardation in vivo but is involved in the maintenance of the growth plate.
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Affiliation(s)
- H C Owen
- Bone Biology Group, Division of Developmental Biology, The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Roslin, Edinburgh, Midlothian, EH25 9PS, UK
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20
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Bassett JHD, Williams GR. Critical role of the hypothalamic-pituitary-thyroid axis in bone. Bone 2008; 43:418-26. [PMID: 18585995 DOI: 10.1016/j.bone.2008.05.007] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2008] [Revised: 05/01/2008] [Accepted: 05/07/2008] [Indexed: 11/25/2022]
Abstract
Studies in genetically modified mice have highlighted the importance of the hypothalamic-pituitary-thyroid (HPT) axis during skeletal development and the maintenance of adult bone. Recently, the conventional view that skeletal responses to abnormal thyroid status result solely from altered T3 action in bone has been complicated by studies proposing TSH as a negative regulator of bone turnover. Although skeletal consequences of thyrotoxicosis may result from thyroid hormone excess or TSH deficiency, the two alternatives are not necessarily mutually exclusive and cannot easily be differentiated because the HPT axis maintains them in a physiological reciprocal relationship. By contrast, situations in which this inverse relationship is disrupted have the potential to resolve the roles of T3 and TSH in the skeleton. We discuss these situations and the relative importance of T3 and TSH in skeletal homeostasis.
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Affiliation(s)
- J H Duncan Bassett
- Molecular Endocrinology Group, Division of Medicine and MRC Clinical Sciences Centre, Imperial College London, Hammersmith Hospital, London, W12 0NN, UK.
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21
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Overexpression of Spry1 in chondrocytes causes attenuated FGFR ubiquitination and sustained ERK activation resulting in chondrodysplasia. Dev Biol 2008; 321:64-76. [PMID: 18582454 DOI: 10.1016/j.ydbio.2008.05.555] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2007] [Revised: 05/29/2008] [Accepted: 05/29/2008] [Indexed: 11/20/2022]
Abstract
The FGF signaling pathway plays essential roles in endochondral ossification by regulating osteoblast proliferation and differentiation, chondrocyte proliferation, hypertrophy, and apoptosis. FGF signaling is controlled by the complementary action of both positive and negative regulators of the signal transduction pathway. The Spry proteins are crucial regulators of receptor tyrosine kinase-mediated MAPK signaling activity. Sprys are expressed in close proximity to FGF signaling centers and regulate FGFR-ERK-mediated organogenesis. During endochondral ossification, Spry genes are expressed in prehypertrophic and hypertrophic chondrocytes. Using a conditional transgenic approach in chondrocytes in vivo, the forced expression of Spry1 resulted in neonatal lethality with accompanying skeletal abnormalities resembling thanatophoric dysplasia II, including increased apoptosis and decreased chondrocyte proliferation in the presumptive reserve and proliferating zones. In vitro chondrocyte cultures recapitulated the inhibitory effect of Spry1 on chondrocyte proliferation. In addition, overexpression of Spry1 resulted in sustained ERK activation and increased expression of p21 and STAT1. Immunoprecipitation experiments revealed that Spry1 expression in chondrocyte cultures resulted in decreased FGFR2 ubiquitination and increased FGFR2 stability. These results suggest that constitutive expression of Spry1 in chondrocytes results in attenuated FGFR2 degradation, sustained ERK activation, and up-regulation of p21Cip and STAT1 causing dysregulated chondrocyte proliferation and terminal differentiation.
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22
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Bassett JHD, Williams AJ, Murphy E, Boyde A, Howell PGT, Swinhoe R, Archanco M, Flamant F, Samarut J, Costagliola S, Vassart G, Weiss RE, Refetoff S, Williams GR. A lack of thyroid hormones rather than excess thyrotropin causes abnormal skeletal development in hypothyroidism. Mol Endocrinol 2007; 22:501-12. [PMID: 17932107 DOI: 10.1210/me.2007-0221] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
By proposing TSH as a key negative regulator of bone turnover, recent studies in TSH receptor (TSHR) null mice challenged the established view that skeletal responses to disruption of the hypothalamic-pituitary-thyroid axis result from altered thyroid hormone (T(3)) action in bone. Importantly, this hypothesis does not explain the increased risk of osteoporosis in Graves' disease patients, in which circulating TSHR-stimulating antibodies are pathognomonic. To determine the relative importance of T(3) and TSH in bone, we compared the skeletal phenotypes of two mouse models of congenital hypothyroidism in which the normal reciprocal relationship between thyroid hormones and TSH was intact or disrupted. Pax8 null (Pax8(-/-)) mice have a 1900-fold increase in TSH and a normal TSHR, whereas hyt/hyt mice have a 2300-fold elevation of TSH but a nonfunctional TSHR. We reasoned these mice must display opposing skeletal phenotypes if TSH has a major role in bone, whereas they would be similar if thyroid hormone actions predominate. Pax8(-/-) and hyt/hyt mice both displayed delayed ossification, reduced cortical bone, a trabecular bone remodeling defect, and reduced bone mineralization, thus indicating that the skeletal abnormalities of congenital hypothyroidism are independent of TSH. Treatment of primary osteoblasts and osteoclasts with TSH or a TSHR-stimulating antibody failed to induce a cAMP response. Furthermore, TSH did not affect the differentiation or function of osteoblasts or osteoclasts in vitro. These data indicate the hypothalamic-pituitary-thyroid axis regulates skeletal development via the actions of T(3).
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Affiliation(s)
- J H Duncan Bassett
- Molecular Endocrinology Group, Medical Research Council Clinical Sciences Centre, Hammersmith Hospital, Du Cane Road, London, United Kingdom
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23
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Yeh N, Miller JP, Gaur T, Capellini TD, Nikolich-Zugich J, de la Hoz C, Selleri L, Bromage TG, van Wijnen AJ, Stein GS, Lian JB, Vidal A, Koff A. Cooperation between p27 and p107 during endochondral ossification suggests a genetic pathway controlled by p27 and p130. Mol Cell Biol 2007; 27:5161-71. [PMID: 17502351 PMCID: PMC1951950 DOI: 10.1128/mcb.02431-06] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2006] [Revised: 02/21/2007] [Accepted: 05/02/2007] [Indexed: 02/05/2023] Open
Abstract
Pocket proteins and cyclin-dependent kinase (CDK) inhibitors negatively regulate cell proliferation and can promote differentiation. However, which members of these gene families, which cell type they interact in, and what they do to promote differentiation in that cell type during mouse development are largely unknown. To identify the cell types in which p107 and p27 interact, we generated compound mutant mice. These mice were null for p107 and had a deletion in p27 that prevented its binding to cyclin-CDK complexes. Although a fraction of these animals survived into adulthood and looked similar to single p27 mutant mice, a larger number of animals died at birth or within a few weeks thereafter. These animals displayed defects in chondrocyte maturation and endochondral bone formation. Proliferation of chondrocytes was increased, and ectopic ossification was observed. Uncommitted mouse embryo fibroblasts could be induced into the chondrocytic lineage ex vivo, but these cells failed to mature normally. These results demonstrate that p27 carries out overlapping functions with p107 in controlling cell cycle exit during chondrocyte maturation. The phenotypic similarities between p107(-/-) p27(D51/D51) and p107(-/-) p130(-/-) mice and the cells derived from them suggest that p27 and p130 act in an analogous pathway during chondrocyte maturation.
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Affiliation(s)
- Nancy Yeh
- Sloan-Kettering Institute, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA
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24
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Woodmansee WW, Kerr JM, Tucker EA, Mitchell JR, Haakinson DJ, Gordon DF, Ridgway EC, Wood WM. The proliferative status of thyrotropes is dependent on modulation of specific cell cycle regulators by thyroid hormone. Endocrinology 2006; 147:272-82. [PMID: 16223861 DOI: 10.1210/en.2005-1013] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
In this report we have examined changes in cell growth parameters, cell cycle effectors, and signaling pathways that accompany thyrotrope growth arrest by thyroid hormone (TH) and growth resumption after its withdrawal. Flow cytometry and immunohistochemistry of proliferation markers demonstrated that TH treatment of thyrotrope tumors resulted in a reduction in the fraction of cells in S-phase that is restored upon TH withdrawal. This is accompanied by dephosphorylation and rephosphorylation of retinoblastoma (Rb) protein. The expression levels of cyclin-dependent kinase 2 and cyclin A, as well as cyclin-dependent kinase 1 and cyclin B, were decreased by TH, and after withdrawal not only did these regulators of Rb phosphorylation and mitosis increase in their expression but so too did the D1 and D3 cyclins. We also noted a rapid induction and subsequent disappearance of the type 5 receptor for the growth inhibitor somatostatin with TH treatment and withdrawal, respectively. Because somatostatin can arrest growth by activating MAPK pathways, we examined these pathways in TtT-97 tumors and found that the ERK pathway and several of its upstream and downstream effectors, including cAMP response element binding protein, were activated with TH treatment and deactivated after its withdrawal. This led to the hypothesis that TH, acting through increased type 5 somatostatin receptor, could activate the ERK pathway leading to cAMP response element binding protein-dependent decreased expression of critical cell cycle proteins, specifically cyclin A, resulting in hypophosphorylation of Rb and its subsequent arrest of S-phase progression. These processes are reversed when TH is withdrawn, resulting in an increase in the fraction of S-phase cells.
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Affiliation(s)
- Whitney W Woodmansee
- Division of Endocrinology, Metabolism, and Diabetes, University of Colorado at Denver and Health Sciences Center, Aurora, Colorado 80045, USA
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25
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Shao YY, Wang L, Hicks DG, Tarr S, Ballock RT. Expression and activation of peroxisome proliferator-activated receptors in growth plate chondrocytes. J Orthop Res 2005; 23:1139-45. [PMID: 15878253 DOI: 10.1016/j.orthres.2005.02.011] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Revised: 02/16/2005] [Accepted: 02/21/2005] [Indexed: 02/04/2023]
Abstract
Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a nuclear hormone receptor that is involved in a wide range of cellular processes. Although it is known that PPAR-gamma plays an important role in cell cycle control, inflammation, apoptotic cell death, and other cellular processes, the role of PPAR-gamma in the normal and pathological function of growth plate chondrocytes has not been investigated. The purpose of this study was to determine if PPARs are expressed in growth plate chondrocytes and to describe the biological effect of PPAR activation in these cells. The results demonstrate the presence of three PPAR isoforms (alpha, delta, and gamma) in growth plate cartilage. Activation of PPAR-gamma by ciglitazone in growth plate chondrocytes inhibits T(3) induced terminal differentiation and promotes apoptosis through increased levels of caspase 3/7 activity and decreased expression of the anti-apoptotic protein Bcl-2.
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Affiliation(s)
- Yvonne Y Shao
- Departments of Orthopaedic Surgery and Biomedical Engineering, Orthopaedic Research Center, The Cleveland Clinic Foundation, Cleveland, OH 44195, USA
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26
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Holsberger DR, Cooke PS. Understanding the role of thyroid hormone in Sertoli cell development: a mechanistic hypothesis. Cell Tissue Res 2005; 322:133-40. [PMID: 15856309 DOI: 10.1007/s00441-005-1082-z] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2004] [Accepted: 01/21/2005] [Indexed: 10/25/2022]
Abstract
More than a decade of research has shown that Sertoli cell proliferation is regulated by thyroid hormone. Neonatal hypothyroidism lengthens the period of Sertoli cell proliferation, leading to increases in Sertoli cell number, testis weight, and daily sperm production (DSP) when euthyroidism is re-established. In contrast, the neonatal Sertoli cell proliferative period is shortened under hyperthyroid conditions, but the mechanism by which thyroid hormone is able to negatively regulate Sertoli cell proliferation has been unclear. Recent progress in the understanding of the cell cycle has provided the opportunity to dissect the molecular targets responsible for thyroid-hormone-mediated effects on Sertoli cell proliferation. In this review, we discuss recent results indicating a critical role for the cyclin-dependent kinase inhibitors (CDKI) p27(Kip1) and p21(Cip1) in establishing Sertoli cell number, testis weight, and DSP, and the ability of thyroid hormone to modulate these CDKIs. Based on these recent results, we propose a working hypothesis for the way in which thyroid hormone regulates the withdrawal of the cell cycle by controlling CDKI degradation. Finally, although Sertoli cells have been shown to have two biologically active thyroid hormone receptor (TR) isoforms, TRalpha1 and TRbeta1, experiments with transgenic mice lacking TRalpha or TRbeta illustrate that only one TR mediates thyroid hormone effects in neonatal Sertoli cells. Although significant gaps in our knowledge still remain, advances have been made toward appreciation of the molecular sequence of events that occur when thyroid hormone stimulates Sertoli cell maturation.
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Affiliation(s)
- Denise R Holsberger
- Department of Veterinary Biosciences, University of Illinois, 2001 S. Lincoln Avenue, Urbana, IL 61802, USA
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27
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Marchini A, Marttila T, Winter A, Caldeira S, Malanchi I, Blaschke RJ, Häcker B, Rao E, Karperien M, Wit JM, Richter W, Tommasino M, Rappold GA. The Short Stature Homeodomain Protein SHOX Induces Cellular Growth Arrest and Apoptosis and Is Expressed in Human Growth Plate Chondrocytes. J Biol Chem 2004; 279:37103-14. [PMID: 15145945 DOI: 10.1074/jbc.m307006200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mutations in the homeobox gene SHOX cause growth retardation and the skeletal abnormalities associated with Léri-Weill, Langer, and Turner syndromes. Little is known about the mechanism underlying these SHOX-related inherited disorders of bone formation. Here we demonstrate that SHOX expression in osteogenic stable cell lines, primary oral fibroblasts, and primary chondrocytes leads to cell cycle arrest and apoptosis. These events are associated with alterations in the expression of several cellular genes, including pRB, p53, and the cyclin kinase inhibitors p21(Cip1) and p27(Kip1). A SHOX mutant, such as seen in Léri-Weill syndrome patients, does not display these activities of the wild type protein. We have also shown that endogenous SHOX is mainly expressed in hypertrophic/apoptotic chondrocytes of the growth plate, strongly suggesting that the protein plays a direct role in regulating the differentiation of these cells. This study provides the first insight into the biological function of SHOX as regulator of cellular proliferation and viability and relates these cellular events to the phenotypic consequences of SHOX deficiency.
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Affiliation(s)
- Antonio Marchini
- Institute of Human Genetics, University of Heidelberg, Im Neuenheimer Feld 328, D-69120 Heidelberg, Germany
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28
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Wang G, Woods A, Sabari S, Pagnotta L, Stanton LA, Beier F. RhoA/ROCK Signaling Suppresses Hypertrophic Chondrocyte Differentiation. J Biol Chem 2004; 279:13205-14. [PMID: 14726536 DOI: 10.1074/jbc.m311427200] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Coordinated proliferation and differentiation of growth plate chondrocytes is required for normal growth and development of the endochondral skeleton, but little is known about the intracellular signal transduction pathways regulating these processes. We have investigated the roles of the GTPase RhoA and its effector kinases ROCK1/2 in hypertrophic chondrocyte differentiation. RhoA, ROCK1, and ROCK2 are expressed throughout chondrogenic differentiation. RhoA overexpression in chondrogenic ATDC5 cells results in increased proliferation and a marked delay of hypertrophic differentiation, as shown by decreased induction of alkaline phosphatase activity, mineralization, and expression of the hypertrophic markers collagen X, bone sialoprotein, and matrix metalloproteinase 13. These effects are accompanied by activation of cyclin D1 transcription and repression of the collagen X promoter by RhoA. In contrast, inhibition of Rho/ROCK signaling by the pharmacological inhibitor Y27632 inhibits chondrocyte proliferation and accelerates hypertrophic differentiation. Dominant-negative RhoA also inhibits induction of the cyclin D1 promoter by parathyroid hormone-related peptide. Finally, Y27632 treatment partially rescues the effects of RhoA overexpression. In summary, we identify the RhoA/ROCK signaling pathway as a novel and important regulator of chondrocyte proliferation and differentiation.
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Affiliation(s)
- Guoyan Wang
- Department of Physiology and Pharmacology, Canadian Institutes of Health Research Group in Skeletal Development and Remodeling, University of Western Ontario, London, Ontario N6A 5C1, Canada
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29
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Yamada-Okabe T, Aono T, Sakai H, Kashima Y, Yamada-Okabe H. 2,3,7,8-tetrachlorodibenzo-p-dioxin augments the modulation of gene expression mediated by the thyroid hormone receptor. Toxicol Appl Pharmacol 2004; 194:201-10. [PMID: 14761676 DOI: 10.1016/j.taap.2003.09.010] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2003] [Accepted: 09/19/2003] [Indexed: 10/26/2022]
Abstract
Previously, we reported on genes whose expression was highly modulated by T3 in the HeLaTR cells that stably expressed the thyroid hormone receptor (TR). In this study, we examined the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on TR-mediated gene expression. In the HeLaTR cells, T3 induced the expression of the reporter gene in a thyroid hormone responsible element (TRE)-dependent manner. When the cells were cultured in the presence of T3, the addition of TCDD but not 4-hydroxy-2',3,4',5,6'-pentachlorobiphenyl (PCB-OH), bisphenol A (BPA), or di(2-ethylhexyl)phthalate (DEHP) to the culture media further enhanced the T3-induced expression of the reporter gene. RT-PCR revealed that mRNA levels of 4-1BB, fmfc, PSCA, PSG7, RANTES, and TRAF1, which were highly increased by T3, were further elevated in cells exposed to T3 and TCDD. Also, the mRNA level of BMP6, which was decreased by T3, further declined in the cells exposed to both T3 and TCDD. In contrast to the effect of TCDD, PCB-OH suppressed the modulation of these gene expressions by T3. Neither TCDD nor PCB-OH alone affected the expression of 4-1BB, fmfc, PSCA, PSG7, RANTES, TRAF1, or BMP6. These results indicate that TCDD augments the cellular responses to T3 by hyperactivating TR-mediated gene expression, whereas PCB-OH suppresses cellular responses to T3 by negatively regulating it. Based on these findings, enzyme-linked immunosorbent assay (ELISA) for the PSCA protein in the HeLaTR cells was established. Such assays will be useful to monitor the effects of endocrine disrupting chemicals (EDCs) on TR-mediated gene expression.
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Affiliation(s)
- Toshiko Yamada-Okabe
- Department of Hygiene, School of Medicine, Yokohama City University, Yokohama 236-0004, Japan
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30
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Stewart MC, Kadlcek RM, Robbins PD, MacLeod JN, Ballock RT. Expression and activity of the CDK inhibitor p57Kip2 in chondrocytes undergoing hypertrophic differentiation. J Bone Miner Res 2004; 19:123-32. [PMID: 14753744 DOI: 10.1359/jbmr.0301209] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
UNLABELLED Growth plates of p57-null mice exhibit several abnormalities, including loss of collagen type X (CollX) expression. The phenotypic consequences of p57 expression were assessed in an in vitro model of hypertrophic differentiation. Adenoviral p57 expression was not sufficient for CollX expression but did augment induction of CollX by BMP-2. INTRODUCTION During hypertrophic differentiation, chondrocytes pass from an actively proliferative state to a postmitotic, hypertrophic phenotype. The induction of growth arrest is a central feature of this phenotypic transition. Mice lacking the cyclin dependent-kinase inhibitor p57Kip2 exhibit several developmental abnormalities including chondrodysplasia. Although growth plate chondrocytes in p57-null mice undergo growth arrest, they do not express collagen type X, a specific marker of the hypertrophic phenotype. This study was carried out to investigate the link between p57 expression and the induction of collagen type X in chondrocytes and to determine whether p57 overexpression is sufficient for the induction of hypertrophic differentiation. MATERIALS AND METHODS Neonatal rat epiphyseal or growth plate chondrocytes were maintained in an aggregate culture model, in defined, serum-free medium. Protein and mRNA levels were monitored by Western and Northern blot analyses, respectively. Proliferative activity was assessed by fluorescent measurement of total DNA and by 3H-thymidine incorporation rates. An adenoviral vector was used to assess the phenotypic consequences of p57 expression. RESULTS AND CONCLUSIONS During in vitro hypertrophic differentiation, levels of p57 mRNA and protein were constant despite changes in chondrocyte proliferative activity and the induction of hypertrophic-specific genes in response to bone morphogenetic protein (BMP)-2. Adenoviral p57 overexpression induced growth arrest in prehypertrophic epiphyseal chondrocytes in a dose-dependent manner but was not sufficient for the induction of collagen type X, either alone or when coexpressed with the related CDKI p21Cip1. Similar results were obtained with more mature tibial growth plate chondrocytes. p57 overexpression did augment collagen type X induction by BMP-2. These data indicate that p57-mediated growth arrest is not sufficient for expression of the hypertrophic phenotype, but rather it occurs in parallel with other aspects of the differentiation pathway. Our findings also suggest a contributing role for p57 in the regulation of collagen type X expression in differentiating chondrocytes.
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Affiliation(s)
- Matthew C Stewart
- Department of Veterinary Clinical Medicine, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA.
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31
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Abstract
The longitudinal growth of endochondral bones is governed by proliferation and hypertrophic differentiation of growth plate chondrocytes. Numerous growth factors and hormones have been implicated in the regulation of these processes, but the intracellular mechanisms involved remain much less understood. We had suggested a role of cell-cycle genes in the integration of these diverse extracellular signals and their translation into coordinated proliferation and differentiation of chondrocytes. Numerous recent studies have provided support for such a scenario and provide novel insights into the regulation and function of cell-cycle genes in chondrocytes. This review article summarizes recent progress in the field.
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Affiliation(s)
- Frank Beier
- CIHR Group in Skeletal Development and Remodeling, Department of Physiology and Pharmacology, and School of Dentistry, University of Western Ontario, London, Ontario, Canada.
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Alisi A, Spagnuolo S, Napoletano S, Spaziani A, Leoni S. Thyroid hormones regulate DNA-synthesis and cell-cycle proteins by activation of PKC? and p42/44 MAPK in chick embryo hepatocytes. J Cell Physiol 2004; 201:259-65. [PMID: 15334660 DOI: 10.1002/jcp.20060] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The molecular mechanism by which thyroid hormones exert their effects on cell growth is still unknown. In this study, we used chick embryo hepatocytes at different stages of development as a model to investigate the effect of the two thyroid hormones, T3 and T4, and of their metabolite T2, on the control of cell proliferation. We observed that T2 provokes increase of DNA-synthesis as well as T3 and T4, independently of developmental stage. We found that this stimulatory effect on the S phase is reverted by specific inhibitors of protein kinase C (PKC) and p42/44 mitogen-activated protein kinase (p42/44 MAPK), Ro 31-8220 or PD 98059. Furthermore, the treatment with thyroid hormones induces the activation of PKCalpha and p42/44 MAPK, suggesting their role as possible downstream mediators of cell response mediated by thyroid hormones. The increase of DNA-synthesis is well correlated with the increased levels of cyclin D1 and cdk4 that control the G1 phase, and also with the activities of cell-cycle proteins involved in the G1 to S phase progression, such as cyclin E/A-cdk2 complexes. Interestingly, the activity of cyclin-cdk2 complexes is strongly repressed in the presence of PKC and p42/44 MAPK inhibitors. In conclusion, we demonstrated that the thyroid hormones could modulate different signaling pathways that are able to control cell-cycle progression, mainly during G1/S transition.
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Affiliation(s)
- A Alisi
- Department of Cellular and Developmental Biology, University La Sapienza, Roma, Italy
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33
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Affiliation(s)
- William H Walker
- Department of Cell Biology and Physiology, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
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Holsberger DR, Jirawatnotai S, Kiyokawa H, Cooke PS. Thyroid hormone regulates the cell cycle inhibitor p27Kip1 in postnatal murine Sertoli cells. Endocrinology 2003; 144:3732-8. [PMID: 12933641 DOI: 10.1210/en.2003-0389] [Citation(s) in RCA: 73] [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: 11/19/2022]
Abstract
Thyroid hormone regulates early postnatal Sertoli cell proliferation. Transient neonatal hypothyroidism allows prolonged postnatal Sertoli cell mitogenesis and doubles adult Sertoli cell numbers, testis weight, and sperm production. The mechanism of this effect is unknown. Cell proliferation is stimulated by cyclins and cyclin-dependent kinases and inhibited by cyclin-dependent kinase inhibitors (CDKIs). T(3) regulates the CDKI p27(Kip1) in other cell types, and mice lacking p27(Kip1) have increased testis size. To test the hypothesis that T(3) regulates Sertoli cell mitogenesis by acting through p27(Kip1), we compared expression of p27(Kip1) in Sertoli cells of testes from euthyroid, hypothyroid, and hyperthyroid mice. At postnatal d 5-25, testes were collected and immunostained for p27(Kip1) expression, or Sertoli cells were isolated enzymatically and used for p27(Kip1) Western blotting. p27(Kip1) immunostaining was low in rapidly proliferating 5-d-old Sertoli cells but had increased strongly in nonproliferating 25-d-old Sertoli cells. p27(Kip1) immunostaining was reduced in Sertoli cells from hypothyroid mice compared with euthyroid controls at 10 and 16 d, consistent with increased Sertoli cell proliferation in these mice. Western blotting corroborated the p27(Kip1) immunostaining, and p27(Kip1) expression was greater in Sertoli cells from control compared with hypothyroid mice at postnatal d 10 and 16, but p27(Kip1) expression was comparable by d 25. Hyperthyroidism increased p27(Kip1) immunostaining relative to controls, and Western analysis indicated that Sertoli cells from 10-d-old hyperthyroid mice expressed more p27(Kip1) than control mice. These results indicate that thyroid hormone status affects p27(Kip1) expression in neonatal Sertoli cells, suggesting that T(3) effects on Sertoli cell proliferation may be mediated through this CDKI.
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Affiliation(s)
- Denise R Holsberger
- Department of Veterinary Biosciences, University of Illinois-Urbana, Urbana, Illinois 61802, USA
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35
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Ballock RT, O'Keefe RJ. Physiology and pathophysiology of the growth plate. BIRTH DEFECTS RESEARCH. PART C, EMBRYO TODAY : REVIEWS 2003; 69:123-43. [PMID: 12955857 DOI: 10.1002/bdrc.10014] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Longitudinal growth of the skeleton is a result of endochondral ossification that occurs at the growth plate. Through a sequential process of cell proliferation, extracellular matrix synthesis, cellular hypertrophy, matrix mineralization, vascular invasion, and eventually apoptosis, the cartilage model is continually replaced by bone as length increases. The regulation of longitudinal growth at the growth plate occurs generally through the intimate interaction of circulating systemic hormones and locally produced peptide growth factors, the net result of which is to trigger changes in gene expression by growth plate chondrocytes. This review highlights recent advances in genetics and cell biology that are illuminating the important regulatory mechanisms governing the structure and biology of the growth plate, and provides selected examples of how studies of human mutations have yielded a wealth of new knowledge regarding the normal biology and pathophysiology of growth plate cartilage.
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Affiliation(s)
- R Tracy Ballock
- Orthopaedic Research Center, Departments of Orthopaedic Surgery and Biomedical Engineering, Cleveland Clinic Foundation, Cleveland, Ohio, USA.
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Siebler T, Robson H, Shalet SM, Williams GR. Dexamethasone inhibits and thyroid hormone promotes differentiation of mouse chondrogenic ATDC5 cells. Bone 2002; 31:457-64. [PMID: 12398940 DOI: 10.1016/s8756-3282(02)00855-4] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effects of glucocorticoid (GC) excess, thyrotoxicosis, and hypothyroidism on linear growth indicate that growth plate chondrocytes are exquisitely sensitive to GC and thyroid hormone (T(3)). Murine ATDC5 cells undergo chondrogenesis in vitro and were used to evaluate the effects of dexamethasone (Dex) and T(3) on cell proliferation and differentiation. Immature and differentiated ATDC5 cells expressed glucocorticoid and T(3)-receptor mRNAs. Cells proliferated and organized into cartilage-like nodules after 7 days. Chondrocyte maturation progressed over 9-40 days, with increasing alkaline phosphatase (ALP) activity, secretion of an Alcian blue-positive matrix, and mineralization of cartilage-like nodules. Dex reduced cell number over the 40 day period, causing inhibition of ALP activity and matrix production with failure of mineralization. Following withdrawal of Dex, chondrocytes proliferated and re-entered the differentiation and mineralization program, indicating that GC inhibition of chondrogenesis is reversible. In contrast, T(3) reduced cell proliferation, but induced ALP activity and increased matrix secretion earlier than in control cultures. Thus, GCs and T(3) regulate growth plate chondrocyte differentiation by distinct mechanisms. GCs arrest cell proliferation, differentiation, and cartilage mineralization and maintain chondrocyte precursors in a state of quiescence with the capacity to re-enter chondrogenesis. T(3) inhibits cell proliferation but accelerates differentiation to stimulate chondrogenesis.
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Affiliation(s)
- T Siebler
- Department of Endocrinology, Christie Hospital NHS Trust, Manchester, UK
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Wood WM, Sarapura VD, Dowding JM, Woodmansee WW, Haakinson DJ, Gordon DF, Ridgway EC. Early gene expression changes preceding thyroid hormone-induced involution of a thyrotrope tumor. Endocrinology 2002; 143:347-59. [PMID: 11796486 DOI: 10.1210/endo.143.2.8636] [Citation(s) in RCA: 20] [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: 11/19/2022]
Abstract
Treatment with thyroid hormone (TH) results in shrinkage of a thyrotropic tumor grown in a hypothyroid host. We used microarray and Northern analysis to assess the changes in gene expression that preceded tumor involution. Of the 1,176 genes on the microarray, 7 were up-regulated, whereas 40 were decreased by TH. Many of these were neuroendocrine in nature and related to growth or apoptosis. When we examined transcripts for cell cycle regulators only cyclin-dependent kinase 2, cyclin A and p57 were down-regulated, whereas p15 was induced by TH. Retinoblastoma protein, c-myc, and mdm2 were unchanged, but E2F1 was down-regulated. TH also decreased expression of brain-derived neurotrophic factor, its receptor trkB, and the receptor for TRH. These, in addition to two other genes, neuronatin and PB cadherin, which were up- and down-regulated, respectively, showed a more rapid response to TH than the cell cycle regulators and may represent direct targets of TH. Finally, p19ARF was dramatically induced by TH, and although this protein can stabilize p53 by sequestering mdm2, we found no increase in p53 protein up to 48 h of treatment. In summary, we have described early changes in the expression of genes that may play a role in TH-induced growth arrest of a thyrotropic tumor. These include repression of specific growth factor and receptors and cell cycle genes as well as induction of other factors associated with growth arrest and apoptosis.
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Affiliation(s)
- William M Wood
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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Harvey CB, O'Shea PJ, Scott AJ, Robson H, Siebler T, Shalet SM, Samarut J, Chassande O, Williams GR. Molecular mechanisms of thyroid hormone effects on bone growth and function. Mol Genet Metab 2002; 75:17-30. [PMID: 11825060 DOI: 10.1006/mgme.2001.3268] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Affiliation(s)
- Clare B Harvey
- Division of Medicine & MRC Clinical Sciences Centre, Hammersmith Hospital, Du Cane Road, London, W12 0NN, United Kingdom
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