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Knaup I, Kramann R, Sasula MJ, Mack P, Bastos Craveiro R, Niederau C, Coenen F, Neuss S, Jankowski J, Wolf M. TNF reduces osteogenic cell fate in PDL cells at transcriptional and functional levels without alteration of periodontal proliferative capacity. J Orofac Orthop 2024:10.1007/s00056-024-00541-2. [PMID: 39093345 DOI: 10.1007/s00056-024-00541-2] [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: 01/24/2024] [Accepted: 05/28/2024] [Indexed: 08/04/2024]
Abstract
AIMS To investigate the effect of tumor necrosis factor (TNF) on the growth of human periodontal ligament (PDL) cells, their osteogenic differentiation and modulation of their matrix secretion in vitro. METHODS The influence of 10 ng/ml TNF on proliferation and metabolic activity of PDL cells was analyzed by cell counting (DAPI [4',6-diamidino-2-phenylindole] staining) and the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. In addition, cells were cultured under control conditions and osteogenic conditions (media containing 10 mM β-glycerophosphate). Quantitative expression analysis of genes encoding the osteogenic markers alkaline phosphatase (ALP), collagen type I alpha 1 chain (COL1A1), osteoprotegerin (OPG), and osteopontin (OPN) was performed after 7 and 14 days of cultivation. Calcium deposits were stained with alizarin red. RESULTS Our studies showed that 10 ng/ml TNF did not affect the survival and metabolic activity of PDL cells. Quantitative expression analysis revealed that long-term cultures with TNF impaired osteogenic cell fate at early and late developmental stages. Furthermore, TNF significantly reduced matrix secretion in PDL cells. CONCLUSION The present data confirm TNF as a regulatory factor of proinflammatory remodeling that influences the differentiation behavior but not the metabolism and cell proliferation of the periodontium. Therefore, TNF represents an interesting target for the regulation of orthodontic remodeling processes in the periodontium.
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Affiliation(s)
- Isabel Knaup
- Department of Orthodontics, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany.
| | - Rafael Kramann
- Clinic for Renal and Hypertensive Disorders, Rheumatological and Immunological Diseases (Medical Clinic II), Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Martha-Julia Sasula
- Department of Gastroenterology, Hepatology and Transplant Medicine, Medical Faculty, University of Duisburg-Essen, Essen, Germany
| | - Paula Mack
- Department of Orthodontics, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Rogério Bastos Craveiro
- Department of Orthodontics, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Christian Niederau
- Department of Orthodontics, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Franziska Coenen
- Department of Orthodontics, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
| | - Sabine Neuss
- Helmholtz Institute for Biomedical Engineering, BioInterface Group, RWTH Aachen University, Aachen, Germany
- Institute of Pathology, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Joachim Jankowski
- Institute for Molecular Cardiovascular Research, Medical Faculty, RWTH Aachen University, Aachen, Germany
| | - Michael Wolf
- Department of Orthodontics, Medical Faculty, RWTH Aachen University, Pauwelsstr. 30, 52074, Aachen, Germany
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Zhu L, Zhou C, Chen S, Huang D, Jiang Y, Lan Y, Zou S, Li Y. Osteoporosis and Alveolar Bone Health in Periodontitis Niche: A Predisposing Factors-Centered Review. Cells 2022; 11:3380. [PMID: 36359775 PMCID: PMC9657655 DOI: 10.3390/cells11213380] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 10/19/2022] [Accepted: 10/19/2022] [Indexed: 11/26/2023] Open
Abstract
Periodontitis is a periodontal inflammatory condition that results from disrupted periodontal host-microbe homeostasis, manifested by the destruction of tooth-supporting structures, especially inflammatory alveolar bone loss. Osteoporosis is characterized by systemic deterioration of bone mass and microarchitecture. The roles of many systemic factors have been identified in the pathogenesis of osteoporosis, including endocrine change, metabolic disorders, health-impaired behaviors and mental stress. The prevalence rate of osteoporotic fracture is in sustained elevation in the past decades. Recent studies suggest that individuals with concomitant osteoporosis are more vulnerable to periodontal impairment. Current reviews of worse periodontal status in the context of osteoporosis are limited, mainly centering on the impacts of menopausal and diabetic osteoporosis on periodontitis. Herein, this review article makes an effort to provide a comprehensive view of the relationship between osteoporosis and periodontitis, with a focus on clarifying how those risk factors in osteoporotic populations modify the alveolar bone homeostasis in the periodontitis niche.
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Affiliation(s)
| | | | | | | | | | | | | | - Yuyu Li
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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Lu W, Li X, Yang Y, Yi J, Xie L, Zhao Z, Li Y. PTH/PTHrP in controlled release hydrogel enhances orthodontic tooth movement by regulating periodontal bone remodaling. J Periodontal Res 2021; 56:885-896. [PMID: 33856055 DOI: 10.1111/jre.12885] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 03/23/2021] [Accepted: 04/02/2021] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study aimed to evaluate the effects of local application of parathyroid hormone (PTH) or parathyroid hormone-related protein (PTHrP) on osteogenesis and osteoclastogenesis during orthodontic tooth movement (OTM). BACKGROUND Periodontal bone remodeling is the crucial biological process in the OTM that involves both bone resorption and formation, with the former more important as the initiator. PTH or PTHrP both play dual roles in bone remodeling regulation, and the balance may shift to the bone resorption side when they are given continuously, suggesting them as potential candidate medicine for OTM acceleration. METHODS A total of 40 rats underwent orthodontic mesialization of the maxillary first molars and received no micro-perforation (MOP), or MOP followed by injection of temperature-sensitive hydrogel containing PTH, PTHrP, or normal saline. The rats were sacrificed after 2-week OTM, except for the relapse groups, which had one more week of observation after removal of the force appliances. The amount of tooth movement, rate of relapse after OTM, and effects on the bone remodeling were assessed through micro-computed tomography (μCT) analysis, alkaline phosphatase (ALP) assay, alizarin red staining, tartrate-resistant acid phosphatase (TRAP) staining, immunohistochemistry (IHC) analysis, Western blot (WB), and quantitative real-time polymerase chain reaction (qRT-PCR). The effects of PTHrP on the osteogenic differentiation of human periodontal ligament cells (hPDLCs) were explored in vitro. RESULTS The cumulative release of PTH or PTHrP from PECE hydrogels was beyond 75% at 14 days in a sustained manner. After the intervention in vivo, the distance of OTM in the PTH (0.78 ± 0.06 mm) or PTHrP (0.81 ± 0.04 mm) group was significantly larger than that of the MOP only (0.51 ± 0.04 mm) or the no MOP (0.46 ± 0.05 mm) group. Moreover, PTH injection significantly reduced the rate of relapse after OTM (25.7 ± 4.3%) compared to the control (69.6 ± 6.1%). μCT analysis showed decreased BV/TV, BS/BV, and Tb.N, while increased Tb.Sp of alveolar bone in the PTH or PTHrP group. There were also more TRAP-positive osteoclasts in the PTH or PTHrP group with a significantly enhanced ratio of receptor activator of nuclear factor-κB ligand (RANKL)/osteoprotegerin (OPG). The protein expressions of PTH/PTHrP type 1 receptor (PTHR1), alkaline phosphatase (ALP), osteocalcin (OCN), runt-related transcription factor 2 (RUNX2), and β-catenin were significantly increased in the PTH or PTHrP group, as well as the gene expressions of Pth1r, Bglap, and Alpl. There was no significant difference between the effects of PTH and PTHrP. Nevertheless, inhibition of PTHrP on the osteogenic differentiation of hPDLCs was detected in vitro with decreased expression of OCN, RUNX2, COL-1, and ALP. CONCLUSION Local injection of either PTH or PTHrP carried by controlled release PECE hydrogel similarly enhances OTM in rats through regulating periodontal bone remodeling, which deserves further study for potential clinical application.
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Affiliation(s)
- Wenxin Lu
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Xue Li
- Department of Stomatology, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, Chengdu, China
| | - Yan Yang
- Department of Head and Neck Surgery, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China
| | - Jianru Yi
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Liang Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhihe Zhao
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yu Li
- Department of Orthodontics, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Chang M, Lin H, Fu H, Wang J, Yang Y, Wan Z, Han G. CREB activation affects mesenchymal stem cell migration and differentiation in periodontal tissues due to orthodontic force. Int J Biochem Cell Biol 2020; 129:105862. [PMID: 33045372 DOI: 10.1016/j.biocel.2020.105862] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 09/30/2020] [Accepted: 10/02/2020] [Indexed: 12/31/2022]
Abstract
During the orthodontic tooth movement, cells in periodontal ligament could differentiate into osteoblasts to synthesize alveolar bone as well as affect the proliferation, migration and differentiation of mesenchymal stem cells, which also contribute to bone remodeling. However, the mechanism is still largely elusive. Here, we evaluated the expression of CREB at the tension site of mouse periodontal ligament under orthodontic mechanical strain and in the cyclic tension strain treated human periodontal ligament cells. Then, through gain and loss of function analysis, we revealed that CREB in PDLCs promotes SDF-1 and FGF2 secretion, which enhance the migration and osteoblastic differentiation of BMSCs. We further discovered that CREB transcriptionally activates FGF2 and SDF-1 expressions by binding to the promoter regions.In conclusion, this study confirms that CREB is an upregulated gene in periodontal ligament under orthodontic tension strain stimulation and plays an important role in regulating BMSCs' physiological activity in orthodontic tension strain-induced bone formation.
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Affiliation(s)
- Maolin Chang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Heng Lin
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Haidi Fu
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Jie Wang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Yang Yang
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Ziqiu Wan
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Guangli Han
- State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory of Oral Biomedicine Ministry of Education, School & Hospital of Stomatology, Wuhan University, Wuhan, China.
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He Y, Li M, Tong G, Meng Y, Hao S, Hu S, Yan W, Yang D. hPTH(3-34)(29-34) selectively activated PKC and mimicked osteoanabolic effects of hPTH(1-34). Bone 2020; 135:115326. [PMID: 32200023 DOI: 10.1016/j.bone.2020.115326] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Revised: 03/15/2020] [Accepted: 03/17/2020] [Indexed: 01/07/2023]
Abstract
Teriparatide (hPTH(1-34)) exhibits both osteoanabolic and osteocatabolic effects. We generated a novel PTH analog by duplicating the PTH(29-34) domain to hPTH(3-34) (named MY-1), which was identified to activate PKC but not PLC and cAMP/PKA signaling. It increased osteo-differentiation but did not affect osteoclastogenesis and RANKL expression in primary osteoblasts or bone marrow cells. MY-1 and hPTH(1-34) increased the synthesis and decreased the degradation οf β-catenin protein in osteoblasts, while PKC inhibitor blunted such effects. In vivo results indicated that intermittent MY-1 and hPTH(1-34) prevented bone loss in ovariectomized mice, and that MY-1 infusion increased bone volume in normal mice. Histological analysis observed more osteoclasts surrounding the cancellous bone surface in hPTH(1-34), but not MY-1 treated mice. We conclude that MY-1 mimicked the osteoanabolic but not the osteocatabolic effects of hPTH(1-34), which is related to PKC and β-catenin signaling. Such anabolic-only analog provides a new strategy to study PTH's versatile functions and design new medicines to treat osteoporosis and bone defects.
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Affiliation(s)
- Youhua He
- Department of Orthopedics-Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Minghan Li
- Department of Orthopedics-Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Guojun Tong
- Department of Orthopedics-Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Yue Meng
- Department of Orthopedics-Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Song Hao
- Department of Orthopedics-Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Shaoyu Hu
- Department of Orthopedics-Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China
| | - Wenjuan Yan
- Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
| | - Dehong Yang
- Department of Orthopedics-Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
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Xu L, Mei L, Zhao R, Yi J, Jiang Y, Li R, Zhao Y, Pi L, Li Y. The effects of intro-oral parathyroid hormone on the healing of tooth extraction socket: an experimental study on hyperglycemic rats. J Appl Oral Sci 2020; 28:e20190690. [PMID: 32348445 PMCID: PMC7185986 DOI: 10.1590/1678-7757-2019-0690] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 02/24/2020] [Indexed: 02/05/2023] Open
Abstract
Objective To investigate the effects of intro-oral injection of parathyroid hormone (PTH) on tooth extraction wound healing in hyperglycemic rats. Methodology 60 male Sprague-Dawley rats were randomly divided into the normal group (n=30) and DM group (n=30). Type 1 diabetes mellitus (DM) was induced by streptozotocin. After extracting the left first molar of all rats, each group was further divided into 3 subgroups (n=10 per subgroup), receiving the administration of intermittent PTH, continuous PTH and saline (control), respectively. The intermittent-PTH group received intra-oral injection of PTH three times per week for two weeks. A thermosensitive controlled-release hydrogel was synthesized for continuous-PTH administration. The serum chemistry was determined to evaluate the systemic condition. All animals were sacrificed after 14 days. Micro-computed tomography (Micro-CT) and histological analyses were used to evaluate the healing of extraction sockets. Results The level of serum glucose in the DM groups was significantly higher than that in the non-DM groups (p<0.05); the level of serum calcium was similar in all groups (p>0.05). Micro-CT analysis showed that the DM group had a significantly lower alveolar bone trabecular number (Tb.N) and higher trabecular separation (Tb.Sp) than the normal group (p<0.05). The histological analyses showed that no significant difference in the amount of new bone (hard tissue) formation was found between the PTH and non-PTH groups (p>0.05). Conclusions Bone formation in the extraction socket of the type 1 diabetic rats was reduced. PTH did not improve the healing of hard and soft tissues. The different PTH administration regimes (continuous vs. intermittent) had similar effect on tissue healing. These results demonstrated that the metabolic characteristics of the hyperglycemic rats produced a condition that was unable to respond to PTH treatment.
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Affiliation(s)
- Lin Xu
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Li Mei
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, New Zealand
| | - Rui Zhao
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jianru Yi
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yixuan Jiang
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Ruomei Li
- Ninth People's Hospital, School of Stomatology, Shanghai Jiao Tong University, Shanghai, China
| | - Youliang Zhao
- Department of emergency department, West China Second Hospital, Sichuan University, Chengdu, China
| | - Li Pi
- West China School of Public Health, Sichuan University, Chengdu, China
| | - Yu Li
- National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Houston DA, Myers K, MacRae VE, Staines KA, Farquharson C. The Expression of PHOSPHO1, nSMase2 and TNAP is Coordinately Regulated by Continuous PTH Exposure in Mineralising Osteoblast Cultures. Calcif Tissue Int 2016; 99:510-524. [PMID: 27444010 PMCID: PMC5055575 DOI: 10.1007/s00223-016-0176-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 07/12/2016] [Indexed: 11/25/2022]
Abstract
Sustained exposure to high levels of parathyroid hormone (PTH), as observed in hyperparathyroidism, is catabolic to bone. The increase in the RANKL/OPG ratio in response to continuous PTH, resulting in increased osteoclastogenesis, is well established. However, the effects of prolonged PTH exposure on key regulators of skeletal mineralisation have yet to be investigated. This study sought to examine the temporal expression of PHOSPHO1, TNAP and nSMase2 in mineralising osteoblast-like cell cultures and to investigate the effects of continuous PTH exposure on the expression of these enzymes in vitro. PHOSPHO1, nSMase2 and TNAP expression in cultured MC3T3-C14 cells significantly increased from day 0 to day 10. PTH induced a rapid downregulation of Phospho1 and Smpd3 gene expression in MC3T3-C14 cells and cultured hemi-calvariae. Alpl was differentially regulated by PTH, displaying upregulation in cultured MC3T3-C14 cells and downregulation in hemi-calvariae. PTH was also able to abolish the stimulatory effects of bone morphogenic protein 2 (BMP-2) on Smpd3 and Phospho1 expression. The effects of PTH on Phospho1 expression were mimicked with the cAMP agonist forskolin and blocked by the PKA inhibitor PKI (5-24), highlighting a role for the cAMP/PKA pathway in this regulation. The potent down-regulation of Phospho1 and Smpd3 in osteoblasts in response to continuous PTH may provide a novel explanation for the catabolic effects on the skeleton of such an exposure. Furthermore, our findings support the hypothesis that PHOSPHO1, nSMase2 and TNAP function cooperatively in the initiation of skeletal mineralisation.
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Affiliation(s)
- D A Houston
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK.
| | - K Myers
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - V E MacRae
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - K A Staines
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
| | - C Farquharson
- The Roslin Institute and R(D)SVS, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, Scotland, UK
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Boutin A, Neumann S, Gershengorn MC. Multiple Transduction Pathways Mediate Thyrotropin Receptor Signaling in Preosteoblast-Like Cells. Endocrinology 2016; 157:2173-81. [PMID: 26950201 PMCID: PMC4870888 DOI: 10.1210/en.2015-2040] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/01/2016] [Indexed: 12/20/2022]
Abstract
It has been shown that the TSH receptor (TSHR) couples to a number of different signaling pathways, although the Gs-cAMP pathway has been considered primary. Here, we measured the effects of TSH on bone marker mRNA and protein expression in preosteoblast-like U2OS cells stably expressing TSHRs. We determined which signaling cascades are involved in the regulation of IL-11, osteopontin (OPN), and alkaline phosphatase (ALPL). We demonstrated that TSH-induced up-regulation of IL-11 is primarily mediated via the Gs pathway as IL-11 was up-regulated by forskolin (FSK), an adenylyl cyclase activator, and inhibited by protein kinase A inhibitor H-89 and by silencing of Gαs by small interfering RNA. OPN levels were not affected by FSK, but its up-regulation was inhibited by TSHR/Gi-uncoupling by pertussis toxin. Pertussis toxin decreased p38 MAPK kinase phosphorylation, and a p38 inhibitor and small interfering RNA knockdown of p38α inhibited OPN induction by TSH. Up-regulation of ALPL expression required high doses of TSH (EC50 = 395nM), whereas low doses (EC50 = 19nM) were inhibitory. FSK-stimulated cAMP production decreased basal ALPL expression, whereas protein kinase A inhibition by H-89 and silencing of Gαs increased basal levels of ALPL. Knockdown of Gαq/11 and a protein kinase C inhibitor decreased TSH-stimulated up-regulation of ALPL, whereas a protein kinase C activator increased ALPL levels. A MAPK inhibitor and silencing of ERK1/2 inhibited TSH-stimulated ALPL expression. We conclude that TSH regulates expression of different bone markers via distinct signaling pathways.
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Affiliation(s)
- Alisa Boutin
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Susanne Neumann
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
| | - Marvin C Gershengorn
- Laboratory of Endocrinology and Receptor Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892
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