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Bagwe S, Mehta V, Mathur A, Kumbhalwar A, Bhati A. Role of various pharmacologic agents in alveolar bone regeneration: A review. Natl J Maxillofac Surg 2023; 14:190-197. [PMID: 37661974 PMCID: PMC10474547 DOI: 10.4103/njms.njms_436_21] [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: 07/15/2021] [Revised: 10/21/2021] [Accepted: 11/02/2021] [Indexed: 09/05/2023] Open
Abstract
Alveolar bone and gingiva are components of the periodontium that house the tooth. It constantly adapts itself to the masticatory forces and position of the tooth. However, localized diseases like chronic periodontitis and certain systemic diseases destroy periodontal tissues, which include the alveolar bone. Various pharmacological agents are being explored for their pleiotropic properties to combat the destruction of alveolar bone. This review focuses on the role of pharmacological agents in alveolar bone regeneration.
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Affiliation(s)
| | - Vini Mehta
- Department of Public Health Dentistry, Dr. D.Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pimpri, Pune, Maharashtra, India
| | - Ankita Mathur
- Department of Periodontology, Dr. D.Y. Patil Dental College and Hospital, Dr. D.Y. Patil Vidyapeeth, Pimpri, Pune, Maharashtra, India
| | - Abhishek Kumbhalwar
- Research Consultant, STAT SENSE, Srushti 10, Sector 1 D, Amba Township Pvt. Ltd., Trimandir, Adalaj, Gujarat, India
| | - Ashok Bhati
- Department of Preventive Dental Sciences, College of Dentistry, Jazan University, Saudi Arabia
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2
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Hirayama J, Hattori A, Takahashi A, Furusawa Y, Tabuchi Y, Shibata M, Nagamatsu A, Yano S, Maruyama Y, Matsubara H, Sekiguchi T, Suzuki N. Physiological consequences of space flight, including abnormal bone metabolism, space radiation injury, and circadian clock dysregulation: Implications of melatonin use and regulation as a countermeasure. J Pineal Res 2023; 74:e12834. [PMID: 36203395 DOI: 10.1111/jpi.12834] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 10/03/2022] [Accepted: 10/04/2022] [Indexed: 12/15/2022]
Abstract
Exposure to the space environment induces a number of pathophysiological outcomes in astronauts, including bone demineralization, sleep disorders, circadian clock dysregulation, cardiovascular and metabolic dysfunction, and reduced immune system function. A recent report describing experiments aboard the Space Shuttle mission, STS-132, showed that the level of melatonin, a hormone that provides the biochemical signal of darkness, was decreased during microgravity in an in vitro culture model. Additionally, abnormal lighting conditions in outer space, such as low light intensity in orbital spacecraft and the altered 24-h light-dark cycles, may result in the dysregulation of melatonin rhythms and the misalignment of the circadian clock from sleep and work schedules in astronauts. Studies on Earth have demonstrated that melatonin regulates various physiological functions including bone metabolism. These data suggest that the abnormal regulation of melatonin in outer space may contribute to pathophysiological conditions of astronauts. In addition, experiments with high-linear energy transfer radiation, a ground-based model of space radiation, showed that melatonin may serve as a protectant against space radiation. Gene expression profiling using an in vitro culture model exposed to space flight during the STS-132 mission, showed that space radiation alters the expression of DNA repair and oxidative stress response genes, indicating that melatonin counteracts the expression of these genes responsive to space radiation to promote cell survival. These findings implicate the use of exogenous melatonin and the regulation of endogenous melatonin as countermeasures for the physiological consequences of space flight.
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Affiliation(s)
- Jun Hirayama
- Department of Clinical Engineering, Faculty of Health Sciences & Division of Health Sciences, Graduate School of Sustainable Systems Science, Komatsu University, Komatsu, Japan
| | - Atsuhiko Hattori
- Department of Biology, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Japan
| | | | - Yukihiro Furusawa
- Department of Pharmaceutical Engineering, Faculty of Engineering, Toyama Prefectural University, Toyama, Japan
| | - Yoshiaki Tabuchi
- Life Science Research Center, University of Toyama, Toyama, Japan
| | - Masahiro Shibata
- Department of Biology, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Japan
| | | | - Sachiko Yano
- Japan Aerospace Exploration Agency, Tsukuba, Japan
| | - Yusuke Maruyama
- Department of Biology, College of Liberal Arts and Sciences, Tokyo Medical and Dental University, Ichikawa, Japan
| | - Hajime Matsubara
- Noto Center for Fisheries Science and Technology, Kanazawa University, Noto-cho, Ishikawa, Japan
| | - Toshio Sekiguchi
- Noto Marine Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, Noto-cho, Japan
| | - Nobuo Suzuki
- Noto Marine Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, Noto-cho, Japan
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3
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Bai Y, Liu X, Li J, Wang Z, Guo Q, Xiao M, Cooper PR, Yu Q, He W. Stage-Dependent Regulation of Dental Pulp Stem Cell Odontogenic Differentiation by Transforming Growth Factor- β1. Stem Cells Int 2022; 2022:2361376. [PMID: 36338026 PMCID: PMC9629931 DOI: 10.1155/2022/2361376] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 09/21/2022] [Accepted: 09/29/2022] [Indexed: 10/12/2023] Open
Abstract
Transforming growth factor-β1 (TGF-β1) is an important multifunctional cytokine with dual effects on stem cell differentiation. However, the role of TGF-β1 on odontogenic differentiation of dental pulp stem cells (DPSCs) remains to be entirely elucidated. In the present study, we initially investigated the effect of TGF-β1 at a range of concentrations (0.1-5 ng/mL) on the proliferation, cell cycle, and apoptosis of DPSCs. Subsequently, to determine the effect of TGF-β1 on odontogenic differentiation, alkaline phosphatase (ALP) activity and Alizarin Red S (ARS) staining assays at different concentrations and time points were performed. Quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis were used to determine the levels of odonto-/osteo-genic differentiation-related gene and protein expression, respectively. For in vivo studies, newly formed tissue was assessed by Masson's trichrome and von Kossa staining. Data indicated that TGF-β1 inhibited DPSCs proliferation in a concentration-and time-dependent manner (p < 0.05) and induced cell cycle arrest but did not affect apoptosis. ALP activity was enhanced, while ARS reduced gradually with increasing TGF-β1 concentrations, accompanied by increased expression of early marker genes of odonto-/osteo-genic differentiation and decreased expression of late-stage mineralization marker genes (p < 0.05). ALP expression was elevated in the TGF-β1-treatment group until 14 days, and the intensity of ARS staining was attenuated at days 14 and 21 (p < 0.05). Compared with the control group, abundant collagen but no mineralized tissues were observed in the TGF-β1-treatment group in vivo. Overall, these findings indicate that TGF-β1 promotes odontogenic differentiation of DPSCs at early-stage while inhibiting later-stage mineralization processes.
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Affiliation(s)
- Yu Bai
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry and Endodontics, School of Stomatology, Air Force Medical University, 145 Changle Road, Xi'an 710032, China
| | - Xin Liu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry and Endodontics, School of Stomatology, Air Force Medical University, 145 Changle Road, Xi'an 710032, China
| | - Junqing Li
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry and Endodontics, School of Stomatology, Air Force Medical University, 145 Changle Road, Xi'an 710032, China
- Hospital of Stomatology, Zunyi Medical University, 89 Wu-jiang Dong Road, Zunyi 563003, China
| | - Zhihua Wang
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry and Endodontics, School of Stomatology, Air Force Medical University, 145 Changle Road, Xi'an 710032, China
| | - Qian Guo
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry and Endodontics, School of Stomatology, Air Force Medical University, 145 Changle Road, Xi'an 710032, China
| | - Min Xiao
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry and Endodontics, School of Stomatology, Air Force Medical University, 145 Changle Road, Xi'an 710032, China
| | - Paul R. Cooper
- Department of Oral Sciences, Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, P.O. Box 56, Dunedin 9054, New Zealand
| | - Qing Yu
- State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Key Laboratory of Stomatology, Department of Operative Dentistry and Endodontics, School of Stomatology, Air Force Medical University, 145 Changle Road, Xi'an 710032, China
| | - Wenxi He
- Department of Stomatology, Air Force Medical Center, Air Force Medical University, 30 Fucheng Road, Beijing 100142, China
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4
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Physical Activity-Dependent Regulation of Parathyroid Hormone and Calcium-Phosphorous Metabolism. Int J Mol Sci 2020; 21:ijms21155388. [PMID: 32751307 PMCID: PMC7432834 DOI: 10.3390/ijms21155388] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 07/09/2020] [Accepted: 07/23/2020] [Indexed: 12/14/2022] Open
Abstract
Exercise perturbs homeostasis, alters the levels of circulating mediators and hormones, and increases the demand by skeletal muscles and other vital organs for energy substrates. Exercise also affects bone and mineral metabolism, particularly calcium and phosphate, both of which are essential for muscle contraction, neuromuscular signaling, biosynthesis of adenosine triphosphate (ATP), and other energy substrates. Parathyroid hormone (PTH) is involved in the regulation of calcium and phosphate homeostasis. Understanding the effects of exercise on PTH secretion is fundamental for appreciating how the body adapts to exercise. Altered PTH metabolism underlies hyperparathyroidism and hypoparathyroidism, the complications of which affect the organs involved in calcium and phosphorous metabolism (bone and kidney) and other body systems as well. Exercise affects PTH expression and secretion by altering the circulating levels of calcium and phosphate. In turn, PTH responds directly to exercise and exercise-induced myokines. Here, we review the main concepts of the regulation of PTH expression and secretion under physiological conditions, in acute and chronic exercise, and in relation to PTH-related disorders.
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Abstract
Parathyroid hormone is an essential regulator of extracellular calcium and phosphate. PTH enhances calcium reabsorption while inhibiting phosphate reabsorption in the kidneys, increases the synthesis of 1,25-dihydroxyvitamin D, which then increases gastrointestinal absorption of calcium, and increases bone resorption to increase calcium and phosphate. Parathyroid disease can be an isolated endocrine disorder or part of a complex syndrome. Genetic mutations can account for diseases of parathyroid gland formulation, dysregulation of parathyroid hormone synthesis or secretion, and destruction of the parathyroid glands. Over the years, a number of different options are available for the treatment of different types of parathyroid disease. Therapeutic options include surgical removal of hypersecreting parathyroid tissue, administration of parathyroid hormone, vitamin D, activated vitamin D, calcium, phosphate binders, calcium-sensing receptor, and vitamin D receptor activators to name a few. The accurate assessment of parathyroid hormone also provides essential biochemical information to properly diagnose parathyroid disease. Currently available immunoassays may overestimate or underestimate bioactive parathyroid hormone because of interferences from truncated parathyroid hormone fragments, phosphorylation of parathyroid hormone, and oxidation of amino acids of parathyroid hormone.
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Affiliation(s)
- Edward Ki Yun Leung
- Department of Pathology and Laboratory Medicine, Children's Hospital Los Angeles, Los Angeles, CA, United States; Department of Pathology, Keck School of Medicine of University of Southern California, Los Angeles, CA, United States.
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Kosugi K, Tajima T, Menuki K, Okuma KF, Tokuda K, Fukuda H, Okada Y, Tsukamoto M, Yamanaka Y, Zenke Y, Sakai A. Disruption of the aldehyde dehydrogenase 2 gene increases the bone anabolic response to intermittent PTH treatment in an ovariectomized mouse model. Bone 2020; 136:115370. [PMID: 32325250 DOI: 10.1016/j.bone.2020.115370] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 04/15/2020] [Accepted: 04/18/2020] [Indexed: 12/14/2022]
Abstract
Aldehyde dehydrogenase 2 (ALDH2) is the enzyme that oxidizes the acetaldehyde produced by alcohol metabolism. This variant not only affects the response to alcohol but is also associated with several diseases, such as esophageal cancer, myocardial infarction, and particularly osteoporosis. In our previous study, we reported that compared to wild-type (WT) mice, Aldh2 knockout (KO) mice naturally have a strong bone formation ability, and high expression of parathyroid hormone receptor (PTHR1) in osteocytes. The effect of the Aldh2 gene on bone metabolism in response to intermittent PTH treatment is unknown. The purpose of this study was to clarify the effect of the Aldh2 gene on the bone anabolic response to intermittent PTH treatment in ovariectomized mice. Female KO and WT mice were ovariectomized at 8 weeks of age. At 14 weeks of age, the KO and WT mice were divided into vehicle-treated (Veh) and PTH-treated (PTH) groups (i.e., the WT-Veh, WT-PTH, KO-Veh and KO-PTH groups). PTH (1-34) and vehicle were subcutaneously administered to each group at a dose of 40 μg/kg body weight (BW) five times per week for 4 weeks. Micro-CT showed that the bone volume (BV), trabecular number (Tb.N), connectivity density (Conn.D), and cortical thickness (Ct.Th) values in the KO-PTH mice were significantly higher than those in the KO-Veh mice. Histomorphometric analysis showed that the BV, Tb.N, and mineral apposition rate (MAR) values in the KO-PTH group were significantly higher than those in the KO-Veh group. The mRNA expression level of PTHR1 in the KO-PTH group was significantly increased and that of p21 in the KO-PTH group was significantly decreased compared with the levels in the KO-Veh group. The expression of PTHR in osteocytes from the KO-PTH group was also significantly increased compared with that in osteocytes from the KO-Veh group. Furthermore, cell cultures revealed that the ALP+CFU-f/total CFU-f percentage was significantly higher in the KO-PTH group than in the KO-Veh group. We concluded that in ovariectomized Aldh2 KO mice, the bone anabolic response to intermittent PTH treatment was significantly enhanced compared to that in WT mice, which may be mediated by the high expression level of PTHR1.
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Affiliation(s)
- Kenji Kosugi
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Takafumi Tajima
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan.
| | - Kunitaka Menuki
- Department of Orthopaedic Surgery, Kitakyushu Municipal Yahata Hospital, 2-6-2 Ogura, Yahatahigashi-ku, Kitakyushu 805-8534, Japan
| | - Kayoko Furukawa Okuma
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Kotaro Tokuda
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Hokuto Fukuda
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Yasuaki Okada
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Manabu Tsukamoto
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Yoshiaki Yamanaka
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Yukichi Zenke
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
| | - Akinori Sakai
- Department of Orthopaedic Surgery, University of Occupational and Environmental Health, 1-1 Iseigaoka, Yahatanishi-ku, Kitakyushu 807-8555, Japan
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7
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Hashimoto K, Kaito T, Furuya M, Seno S, Okuzaki D, Kikuta J, Tsukazaki H, Matsuda H, Yoshikawa H, Ishii M. In vivo dynamic analysis of BMP-2-induced ectopic bone formation. Sci Rep 2020; 10:4751. [PMID: 32179857 PMCID: PMC7076033 DOI: 10.1038/s41598-020-61825-2] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Accepted: 03/03/2020] [Indexed: 12/29/2022] Open
Abstract
Bone morphogenetic protein (BMP)-2 plays a central role in bone-tissue engineering because of its potent bone-induction ability. However, the process of BMP-induced bone formation in vivo remains poorly elucidated. Here, we aimed to establish a method for intravital imaging of the entire process of BMP-2-induced ectopic bone formation. Using multicolor intravital imaging in transgenic mice, we visualized the spatiotemporal process of bone induction, including appearance and motility of osteoblasts and osteoclasts, angiogenesis, collagen-fiber formation, and bone-mineral deposition. Furthermore, we investigated how PTH1-34 affects BMP-2-induced bone formation, which revealed that PTH1-34 administration accelerated differentiation and increased the motility of osteoblasts, whereas it decreased morphological changes in osteoclasts. This is the first report on visualization of the entire process of BMP-2-induced bone formation using intravital imaging techniques, which, we believe, will contribute to our understanding of ectopic bone formation and provide new parameters for evaluating bone-forming activity.
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Affiliation(s)
- Kunihiko Hashimoto
- Department of Immunology and Cell Biology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan.,Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Takashi Kaito
- Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.
| | - Masayuki Furuya
- Department of Immunology and Cell Biology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan.,Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan.,Department of Orthopaedic Surgery, Japan Organization of Occupational Health and Safety Osaka Rosai Hospital, Osaka, 591-8025, Japan
| | - Shigeto Seno
- Department of Bioinformatic Engineering, Graduate School of Information Science & Technology, Osaka University, Osaka, 565-0871, Japan
| | - Daisuke Okuzaki
- Genome Information Research Center, Research Institute for Microbial Diseases, Osaka University, Osaka, 565-0871, Japan
| | - Junichi Kikuta
- Department of Immunology and Cell Biology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan
| | - Hiroyuki Tsukazaki
- Department of Immunology and Cell Biology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan.,Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Hideo Matsuda
- Department of Bioinformatic Engineering, Graduate School of Information Science & Technology, Osaka University, Osaka, 565-0871, Japan
| | - Hideki Yoshikawa
- Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Masaru Ishii
- Department of Immunology and Cell Biology, Graduate School of Medicine & Frontier Biosciences, Osaka University, Osaka, 565-0871, Japan.
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Cui C, Zheng L, Fan Y, Zhang J, Xu R, Xie J, Zhou X. Parathyroid hormone ameliorates temporomandibular joint osteoarthritic-like changes related to age. Cell Prolif 2020; 53:e12755. [PMID: 32154622 PMCID: PMC7162802 DOI: 10.1111/cpr.12755] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES Ageing could be a contributing factor to the progression of temporomandibular joint osteoarthritis (TMJ OA), whereas its pathogenesis and potential therapeutic strategy have not been comprehensively investigated. MATERIALS AND METHODS We generated ageing mouse models (45-week and 60-week; 12-week mice as control) and intermittently injected 45-week mice with parathyroid hormone (PTH(1-34)) or vehicle for 4 weeks. Cartilage and subchondral bone of TMJ were analysed by microCT, histological and immunostaining. Western blot, qRT-PCR, ChIP, ELISA and immunohistochemical analysis were utilized to examination the mechanism of PTH(1-34)'s function. RESULTS We showed apparent OA-like phenotypes in ageing mice. PTH treatment could ameliorate the degenerative changes and improve bone microarchitecture in the subchondral bone by activating bone remodelling. Moreover, PTH inhibited phosphorylation level of Smad3, which can combine with p16ink4a gene promoter region, resulting in reduced senescent cells accumulation and increased cellular proliferation of marrow mesenchymal stem cells (MSCs). ELISA also showed relieved levels of specific senescent-associated secretory phenotype (SASP) in ageing mice after PTH treatment. CONCLUSIONS In summary, PTH may reduce the accumulation of senescent cells in subchondral bone by inhibiting p16ink4a and improve bone marrow microenvironment to active bone remodelling process, indicating PTH administration could be a potential preventative and therapeutic treatment for age-related TMJ OA.
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Affiliation(s)
- Chen Cui
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Liwei Zheng
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Yi Fan
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Jun Zhang
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China.,School of Stomatology, Kunming Medical University, Kunming, China
| | - Ruoshi Xu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Sichuan, China
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9
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Yang M, Arai A, Udagawa N, Zhao L, Nishida D, Murakami K, Hiraga T, Takao-Kawabata R, Matsuo K, Komori T, Kobayashi Y, Takahashi N, Isogai Y, Ishizuya T, Yamaguchi A, Mizoguchi T. Parathyroid Hormone Shifts Cell Fate of a Leptin Receptor-Marked Stromal Population from Adipogenic to Osteoblastic Lineage. J Bone Miner Res 2019; 34:1952-1963. [PMID: 31173642 DOI: 10.1002/jbmr.3811] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 05/24/2019] [Accepted: 05/28/2019] [Indexed: 12/28/2022]
Abstract
Intermittent parathyroid hormone (iPTH) treatment induces bone anabolic effects that result in the recovery of osteoporotic bone loss. Human PTH is usually given to osteoporotic patients because it induces osteoblastogenesis. However, the mechanism by which PTH stimulates the expansion of stromal cell populations and their maturation toward the osteoblastic cell lineage has not be elucidated. Mouse genetic lineage tracing revealed that iPTH treatment induced osteoblastic differentiation of bone marrow (BM) mesenchymal stem and progenitor cells (MSPCs), which carried the leptin receptor (LepR)-Cre. Although these findings suggested that part of the PTH-induced bone anabolic action is exerted because of osteoblastic commitment of MSPCs, little is known about the in vivo mechanistic details of these processes. Here, we showed that LepR+ MSPCs differentiated into type I collagen (Col1)+ mature osteoblasts in response to iPTH treatment. Along with osteoblastogenesis, the number of Col1+ mature osteoblasts increased around the bone surface, although most of them were characterized as quiescent cells. However, the number of LepR-Cre-marked lineage cells in a proliferative state also increased in the vicinity of bone tissue after iPTH treatment. The expression levels of SP7/osterix (Osx) and Col1, which are markers for osteoblasts, were also increased in the LepR+ MSPCs population in response to iPTH treatment. In contrast, the expression levels of Cebpb, Pparg, and Zfp467, which are adipocyte markers, decreased in this population. Consistent with these results, iPTH treatment inhibited 5-fluorouracil- or ovariectomy (OVX)-induced LepR+ MSPC-derived adipogenesis in BM and increased LepR+ MSPC-derived osteoblasts, even under the adipocyte-induced conditions. Treatment of OVX rats with iPTH significantly affected the osteoporotic bone tissue and expansion of the BM adipose tissue. These results indicated that iPTH treatment induced transient proliferation of the LepR+ MSPCs and skewed their lineage differentiation from adipocytes toward osteoblasts, resulting in an expanded, quiescent, and mature osteoblast population. © 2019 American Society for Bone and Mineral Research.
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Affiliation(s)
- Mengyu Yang
- Institute for Oral Science, Matsumoto Dental University, Nagano, Japan
| | - Atsushi Arai
- Department of Orthodontics, Matsumoto Dental University, Nagano, Japan
| | - Nobuyuki Udagawa
- Department of Oral Biochemistry, Matsumoto Dental University, Nagano, Japan
| | - Lijuan Zhao
- Institute for Oral Science, Matsumoto Dental University, Nagano, Japan
| | - Daisuke Nishida
- Institute for Oral Science, Matsumoto Dental University, Nagano, Japan
| | - Kohei Murakami
- Department of Oral Biochemistry, Matsumoto Dental University, Nagano, Japan
| | - Toru Hiraga
- Department of Histology and Cell Biology, Matsumoto Dental University, Nagano, Japan
| | - Ryoko Takao-Kawabata
- Laboratory for Pharmacology, Pharmaceutical Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Koichi Matsuo
- Laboratory of Cell and Tissue Biology, Keio University School of Medicine, Tokyo, Japan
| | - Toshihisa Komori
- Department of Cell Biology, Unit of Basic Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan
| | | | - Naoyuki Takahashi
- Institute for Oral Science, Matsumoto Dental University, Nagano, Japan
| | - Yukihiro Isogai
- Laboratory for Pharmacology, Pharmaceutical Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Toshinori Ishizuya
- Laboratory for Pharmacology, Pharmaceutical Research Center, Asahi Kasei Pharma Corporation, Shizuoka, Japan
| | - Akira Yamaguchi
- Oral Health Science Center, Tokyo Dental College, Tokyo, Japan
| | - Toshihide Mizoguchi
- Institute for Oral Science, Matsumoto Dental University, Nagano, Japan.,Oral Health Science Center, Tokyo Dental College, Tokyo, Japan
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10
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Pal S, Porwal K, Singh H, Malik MY, Rashid M, Kulkarni C, Khan Y, Jagavelu K, Wahajuddin M, Chattopadhyay N. Reversal of Osteopenia in Ovariectomized Rats by Pentoxifylline: Evidence of Osteogenic and Osteo-Angiogenic Roles of the Drug. Calcif Tissue Int 2019; 105:294-307. [PMID: 31175387 DOI: 10.1007/s00223-019-00567-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 05/23/2019] [Indexed: 02/05/2023]
Abstract
Pentoxifylline (PTX) is a non-selective phosphodiesterase inhibitor and is used for the management of intermittent claudication. We tested whether PTX has oral efficacy in stimulating new bone formation. Rat calvarial osteoblasts (RCO) were used to study the effect of PTX on osteoblast differentiation and angiogenesis. Pharmacokinetic and pharmacodynamic studies were carried out in rats to determine an oral dose of PTX. In ovariectomized (OVX) rats with osteopenia, the effect of PTX on various skeletal parameters was studied, and compared with teriparatide. Effect of PTX on angiogenic signaling was studied by immunoblotting and relevant pharmacologic inhibitors. Bone vascularity was measured by intravenous injection of polystyrene fluorospheres followed by in vivo imaging, and angiogenesis was studied in vitro by tubulogenesis of endothelial cells and in vivo by Matrigel plug assay. Effective concentration (EC50) of PTX in RCO was 8.2 nM and plasma PTX level was 7 nM/mL after single oral dosing of 25 mg/kg, which was 1/6th the clinically used dose. At this dose, PTX enhanced bone regeneration at femur osteotomy site and completely restored bone mass, microarchitecture, and strength in OVX rats. Furthermore, PTX increased surface referent bone formation parameters and serum bone formation marker (PINP) without affecting the resorption marker (CTX-1). PTX increased the expression of vascular endothelial growth factor and its receptor in bones and osteoblasts. PTX also increased skeletal vascularity, tubulogenesis of endothelial cells and in vivo angiogenesis. Taken together, our study suggested that PTX at 16% of adult human oral dose completely reversed osteopenia in OVX rats by osteogenic and osteo-angiogenic mechanisms.
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Affiliation(s)
- Subhashis Pal
- Division of Endocrinology, CSIR-Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow, 226031, India
| | - Konica Porwal
- Division of Endocrinology, CSIR-Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow, 226031, India
| | - Himalaya Singh
- Division of Pharmacology, CSIR-CDRI, Lucknow, 226031, India
| | | | - Mamunur Rashid
- Division of Pharmaceutics, CSIR-CDRI, Lucknow, 226031, India
| | - Chirag Kulkarni
- Division of Endocrinology, CSIR-Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow, 226031, India
| | - Yasir Khan
- Division of Endocrinology, CSIR-Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow, 226031, India
| | | | | | - Naibedya Chattopadhyay
- Division of Endocrinology, CSIR-Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow, 226031, India.
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Abstract
Parathyroid hormone (PTH) is the major secretory product of the parathyroid glands, and in hypocalcemic conditions, can enhance renal calcium reabsorption, increase active vitamin D production to increase intestinal calcium absorption, and mobilize calcium from bone by increasing turnover, mainly but not exclusively in cortical bone. PTH has therefore found clinical use as replacement therapy in hypoparathyroidism. PTH also may have a physiologic role in augmenting bone formation, particularly in trabecular and to some extent in cortical bone. This action has been applied to the clinic to provide anabolic therapy for osteoporosis.
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Affiliation(s)
- David Goltzman
- Department of Medicine and Research Institute of the McGill University Health Centre, 1001 Decarie Boulevard, Montreal, Quebec H4A 3J1, Canada; Departments of Medicine and of Physiology, McGill University, 845 Sherbrooke St West, Montreal, Quebec H3A 0B9, Canada.
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12
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Takahashi A, Mulati M, Saito M, Numata H, Kobayashi Y, Ochi H, Sato S, Kaldis P, Okawa A, Inose H. Loss of cyclin-dependent kinase 1 impairs bone formation, but does not affect the bone-anabolic effects of parathyroid hormone. J Biol Chem 2018; 293:19387-19399. [PMID: 30366983 DOI: 10.1074/jbc.ra118.004834] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/02/2018] [Indexed: 12/31/2022] Open
Abstract
Bone mass is maintained by a balance between osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Although recent genetic studies have uncovered various mechanisms that regulate osteoblast differentiation, the molecular basis of osteoblast proliferation remains unclear. Here, using an osteoblast-specific loss-of-function mouse model, we demonstrate that cyclin-dependent kinase 1 (Cdk1) regulates osteoblast proliferation and differentiation. Quantitative RT-PCR analyses revealed that Cdk1 is highly expressed in bone and is down-regulated upon osteoblast differentiation. We also noted that Cdk1 is dispensable for the bone-anabolic effects of parathyroid hormone (PTH). Cdk1 deletion in osteoblasts led to osteoporosis in adult mice due to low bone formation, but did not affect osteoclast formation in vivo Cdk1 overexpression in osteoblasts promoted proliferation, and conversely, Cdk1 knockdown inhibited osteoblast proliferation and promoted differentiation. Of note, we provide direct evidence that PTH's bone-anabolic effects occur without enhancing osteoblast proliferation in vivo Furthermore, we found that Cdk1 expression in osteoblasts is essential for bone fracture repair. These findings may help reduce the risk of nonunion after bone fracture and identify patients at higher risk for nonresponse to PTH treatment. Collectively, our results indicate that Cdk1 is essential for osteoblast proliferation and that it functions as a molecular switch that shifts osteoblast proliferation to maturation. We therefore conclude that Cdk1 plays an important role in bone formation.
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Affiliation(s)
- Akira Takahashi
- From the Department of Orthopedics, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Mieradili Mulati
- From the Department of Orthopedics, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Masanori Saito
- From the Department of Orthopedics, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Hoashi Numata
- From the Department of Orthopedics, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Yutaka Kobayashi
- From the Department of Orthopedics, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Hiroki Ochi
- the Department of Physiology and Cell Biology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Shingo Sato
- the Department of Physiology and Cell Biology, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Philipp Kaldis
- the Institute of Molecular and Cell Biology (IMCB), Agency for Science, Technology, and Research (A*STAR), Singapore 138673, Republic of Singapore, and.,the Department of Biochemistry, National University of Singapore (NUS), Singapore 117597, Republic of Singapore
| | - Atsushi Okawa
- From the Department of Orthopedics, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan
| | - Hiroyuki Inose
- From the Department of Orthopedics, Graduate School, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, Tokyo 113-8519, Japan,
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13
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Anastasilakis AD, Makras P, Pikilidou M, Tournis S, Makris K, Bisbinas I, Tsave O, Yovos JG, Yavropoulou MP. Changes of Circulating MicroRNAs in Response to Treatment With Teriparatide or Denosumab in Postmenopausal Osteoporosis. J Clin Endocrinol Metab 2018; 103:1206-1213. [PMID: 29309589 DOI: 10.1210/jc.2017-02406] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/19/2017] [Indexed: 02/10/2023]
Abstract
CONTEXT Expression of microRNAs (miRs) related to bone metabolism in the serum may be affected by antiosteoporotic treatment. OBJECTIVE To investigate the effect of two antiosteoporotic agents with opposite effects on bone metabolism on miR expression profile in the serum. DESIGN Observational, open label, nonrandomized clinical trial. SETTING The outpatient clinics for Metabolic Bone Diseases of 424 General Military Hospital, Thessaloniki, Greece. PATIENTS AND INTERVENTIONS Postmenopausal women with low bone mass were treated with either teriparatide (TPTD; n = 30) or denosumab (n = 30) for 12 months. MAIN OUTCOME MEASURES Changes in the serum expression of selected miRs linked to bone metabolism at 3 and 12 months of treatment. Secondary measurements: associations of measured miRs with changes in bone mineral density (BMD) at 12 months and the bone turnover markers (BTMs) C-terminal cross-linking telopeptide of type I collagen and procollagen type I N-terminal propeptide at 3 and 12 months. RESULTS We found significantly decreased relative expression of miR-33-3p at 3 months (P = 0.03) and of miR-133a at 12 months (P = 0.042) of TPTD treatment. BMD values at 12 months of TPTD treatment were significantly and inversely correlated with miR-124-3p expression at 3 months (P = 0.008). Relative expression of miR-24-3p and miR-27a was correlated with changes in BTMs during TPTD treatment and of miR-21-5p, miR-23a-3p, miR-26a-5p, miR-27a, miR-222-5p, and miR-335-5p with changes in BTMs during denosumab treatment. CONCLUSIONS Circulating miRs are differentially affected by treatment with TPTD and denosumab. TPTD affects the relative expression of miRs related to the expression of RUNX-2 (miR-33) and DKK-1 gene (miR-133).
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Affiliation(s)
| | - Polyzois Makras
- Department of Endocrinology and Diabetes, 251 Hellenic Air Force and VA General Hospital, Athens, Greece
| | - Maria Pikilidou
- Laboratory of Clinical and Molecular Endocrinology, First Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Symeon Tournis
- Laboratory of Research of Musculoskeletal System "Th. Garofalidis," Medical School, University of Athens, KAT Hospital, Athens, Greece
| | - Konstantinos Makris
- Laboratory of Research of Musculoskeletal System "Th. Garofalidis," Medical School, University of Athens, KAT Hospital, Athens, Greece
| | - Ilias Bisbinas
- First Department of Orthopedics, 424 General Military Hospital, Thessaloniki, Greece
| | - Olga Tsave
- Laboratory of Clinical and Molecular Endocrinology, First Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - John G Yovos
- Laboratory of Clinical and Molecular Endocrinology, First Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Maria P Yavropoulou
- Laboratory of Clinical and Molecular Endocrinology, First Department of Internal Medicine, AHEPA University Hospital, Aristotle University of Thessaloniki, Thessaloniki, Greece
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14
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Mizuno M, Morinaga H, Mukai K, Kanayama K, Shibutani T. Parathyroid Hormone (1-34) Enhances Bone Regeneration in Rats with Cranial Bone Defects. J HARD TISSUE BIOL 2018. [DOI: 10.2485/jhtb.27.303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Mao Mizuno
- Department of Periodontology, Division of Oral Infections and Health Science, Asahi University School of Dentistry
| | - Hirotugu Morinaga
- Department of Periodontology, Division of Oral Infections and Health Science, Asahi University School of Dentistry
| | - Keisuke Mukai
- Department of Periodontology, Division of Oral Infections and Health Science, Asahi University School of Dentistry
| | - Keiichi Kanayama
- Department of Periodontology, Division of Oral Infections and Health Science, Asahi University School of Dentistry
| | - Toshiaki Shibutani
- Department of Periodontology, Division of Oral Infections and Health Science, Asahi University School of Dentistry
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15
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Kot A, Zhong ZA, Zhang H, Lay YAE, Lane NE, Yao W. Sex dimorphic regulation of osteoprogenitor progesterone in bone stromal cells. J Mol Endocrinol 2017; 59:351-363. [PMID: 28871061 PMCID: PMC5633481 DOI: 10.1530/jme-17-0076] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 09/04/2017] [Indexed: 12/13/2022]
Abstract
Increasing peak bone mass is a promising strategy to prevent osteoporosis. A mouse model of global progesterone receptor (PR) ablation showed increased bone mass through a sex-dependent mechanism. Cre-Lox recombination was used to generate a mouse model of osteoprogenitor-specific PR inactivation, which recapitulated the high bone mass phenotype seen in the PR global knockout mouse mode. In this work, we employed RNA sequencing analysis to evaluate sex-independent and sex-dependent differences in gene transcription of osteoprogenitors of wild-type and PR conditional knockout mice. PR deletion caused marked sex hormone-dependent changes in gene transcription in male mice as compared to wild-type controls. These transcriptional differences revealed dysregulation in pathways involving immunomodulation, osteoclasts, bone anabolism, extracellular matrix interaction and matrix interaction. These results identified many potential mechanisms that may explain our observed high bone mass phenotype with sex differences when PR was selectively deleted in the MSCs.
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Affiliation(s)
- Alexander Kot
- Center for Musculoskeletal HealthDepartment of Internal Medicine, University of California Davis Medical Center, Sacramento, California, USA
| | - Zhendong A Zhong
- Center for Musculoskeletal HealthDepartment of Internal Medicine, University of California Davis Medical Center, Sacramento, California, USA
- Center for Cancer and Cell BiologyProgram in Skeletal Disease and Tumor Microenvironment, Van Andel Research Institute, Grand Rapids, Michigan, USA
| | - Hongliang Zhang
- Center for Musculoskeletal HealthDepartment of Internal Medicine, University of California Davis Medical Center, Sacramento, California, USA
- Department of Emergency MedicineCenter for Difficult Diagnoses and Rare Diseases, Second Xiangya Hospital of the Central-South University, Changsha, Hunan, China
| | - Yu-An Evan Lay
- Center for Musculoskeletal HealthDepartment of Internal Medicine, University of California Davis Medical Center, Sacramento, California, USA
| | - Nancy E Lane
- Center for Musculoskeletal HealthDepartment of Internal Medicine, University of California Davis Medical Center, Sacramento, California, USA
| | - Wei Yao
- Center for Musculoskeletal HealthDepartment of Internal Medicine, University of California Davis Medical Center, Sacramento, California, USA
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16
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Chouinard L, Felx M, Mellal N, Varela A, Mann P, Jolette J, Samadfam R, Smith SY, Locher K, Buntich S, Ominsky MS, Pyrah I, Boyce RW. Carcinogenicity risk assessment of romosozumab: A review of scientific weight-of-evidence and findings in a rat lifetime pharmacology study. Regul Toxicol Pharmacol 2016; 81:212-222. [PMID: 27569204 DOI: 10.1016/j.yrtph.2016.08.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 08/18/2016] [Accepted: 08/22/2016] [Indexed: 12/31/2022]
Abstract
Romosozumab is a humanized immunoglobulin G2 monoclonal antibody that binds and blocks the action of sclerostin, a protein secreted by the osteocyte and an extracellular inhibitor of canonical Wnt signaling. Blockade of sclerostin binding to low-density lipoprotein receptor-related proteins 5 and 6 (LRP5 and LRP6) allows Wnt ligands to activate canonical Wnt signaling in bone, increasing bone formation and decreasing bone resorption, making sclerostin an attractive target for osteoporosis therapy. Because romosozumab is a bone-forming agent and an activator of canonical Wnt signaling, questions have arisen regarding a potential carcinogenic risk. Weight-of-evidence factors used in the assessment of human carcinogenic risk of romosozumab included features of canonical Wnt signaling, expression pattern of sclerostin, phenotype of loss-of-function mutations in humans and mice, mode and mechanism of action of romosozumab, and findings from romosozumab chronic toxicity studies in rats and monkeys. Although the weight-of-evidence factors supported that romosozumab would pose a low carcinogenic risk to humans, the carcinogenic potential of romosozumab was assessed in a rat lifetime study. There were no romosozumab-related effects on tumor incidence in rats. The findings of the lifetime study and the weight-of-evidence factors collectively indicate that romosozumab administration would not pose a carcinogenic risk to humans.
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Affiliation(s)
- Luc Chouinard
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Melanie Felx
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Nacera Mellal
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Aurora Varela
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Peter Mann
- EPL NorthWest, 600 North 36th Street, Suite 220, Seattle, WA, 98103, USA
| | - Jacquelin Jolette
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Rana Samadfam
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Susan Y Smith
- Charles River Laboratories, Montreal ULC, 22022 Transcanadienne, Senneville, Quebec, H9X 3R3, Canada
| | - Kathrin Locher
- One Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | - Sabina Buntich
- One Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA, 91320, USA
| | | | - Ian Pyrah
- One Amgen Inc., 1 Amgen Center Drive, Thousand Oaks, CA, 91320, USA
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17
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Broome DT, Datta NS. Mitogen-activated protein kinase phosphatase-1: function and regulation in bone and related tissues. Connect Tissue Res 2016; 57:175-89. [PMID: 27031422 DOI: 10.3109/03008207.2015.1125480] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
In this review, we have highlighted work that has clearly demonstrated that mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1), a negative regulator of MAPKs, is an important signaling mediator in bone, muscle, and fat tissue homeostasis and differentiation. Further, we examined recent studies with particular focus on MKP-1 overexpression or deletion and its impact on tissues connected to bone. We also summarized regulation of MKP-1 by known skeletal regulators like parathyroid hormone (PTH)/PTH-related peptide (PTHrP) and bone morphogenic proteins. MKP-1's integration into the pathophysiological state of osteoporosis, osteoarthritis, rheumatoid arthritis, obesity, and muscular dystrophy are examined to emphasize possible involvement of MKP-1 both at the molecular level and in disease complications such as sarcopenia- or diabetes-related osteoporosis. We predict that understanding the mechanism of MKP-1-mediated signaling in bone-muscle-fat crosstalk will be a key in coordinating their activities and developing therapeutics to improve clinical outcomes for diseases associated with advanced age.
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Affiliation(s)
- David T Broome
- a Division of Endocrinology, Department of Internal Medicine , Wayne State University School of Medicine , Detroit , MI , USA
| | - Nabanita S Datta
- a Division of Endocrinology, Department of Internal Medicine , Wayne State University School of Medicine , Detroit , MI , USA
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18
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Katti KS, Molla MS, Karandish F, Haldar MK, Mallik S, Katti DR. Sequential culture on biomimetic nanoclay scaffolds forms three-dimensional tumoroids. J Biomed Mater Res A 2016; 104:1591-602. [PMID: 26873510 DOI: 10.1002/jbm.a.35685] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Accepted: 02/09/2016] [Indexed: 01/17/2023]
Abstract
In recent times, the limitation of two-dimensional cultures and complexity of in vivo models has paved the way for the development of three-dimensional models for studying cancer. Here we report the development of a new tumor model using PCL/HAPClay scaffolds seeded with a sequential culture of human mesenchymal stem cells (hMSCs) followed by human prostate cancer cells (HPCCs). This nanocomposite system is used as a test-bed for studying cancer metastasis and efficacy of anti-cancer drugs using a polymersome delivery method. A novel sequential cell culture system in three-dimensional in vitro bone model provides a unique bone mimetic environment. The hMSCs seeded scaffolds are seeded with prostate cancer cells after the hMSCs have differentiated into osteoblasts. Sequential culture on the scaffolds has shown formation of tumoroids or microtissue consisting of organized, densely packed round cells with hypoxic core regions similar to in vivo tumors. Such tumoroids are not observed on HPCC seeded scaffolds or when HPCCs sequentially cultured with human osteoblast cells. Clearly, the newly differentiated hMSCs play a vital role in the ability of cancer cells to grow into tumoroids and cause disease. The PCL/HAPclay scaffold system seeded with the sequential culture of hMSCs, and HPCCs presents a good model system for study of the interactions between prostate cancer cells and bone microenvironment. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1591-1602, 2016.
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Affiliation(s)
- Kalpana S Katti
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, North Dakota, 58105
| | - Md Shahjahan Molla
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, North Dakota, 58105
| | - Fataneh Karandish
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, 58105
| | - Manas K Haldar
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, 58105
| | - Sanku Mallik
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo, North Dakota, 58105
| | - Dinesh R Katti
- Department of Civil and Environmental Engineering, North Dakota State University, Fargo, North Dakota, 58105
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19
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Ominsky MS, Brown DL, Van G, Cordover D, Pacheco E, Frazier E, Cherepow L, Higgins-Garn M, Aguirre JI, Wronski TJ, Stolina M, Zhou L, Pyrah I, Boyce RW. Differential temporal effects of sclerostin antibody and parathyroid hormone on cancellous and cortical bone and quantitative differences in effects on the osteoblast lineage in young intact rats. Bone 2015; 81:380-391. [PMID: 26261096 DOI: 10.1016/j.bone.2015.08.007] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Revised: 06/16/2015] [Accepted: 08/06/2015] [Indexed: 12/13/2022]
Abstract
Sclerostin antibody (Scl-Ab) and parathyroid hormone (PTH) are bone-forming agents that have different modes of action on bone, although a study directly comparing their effects has not been conducted. The present study investigated the comparative quantitative effects of these two bone-forming agents over time on bone at the organ, tissue, and cellular level; specifically, at the level of the osteoblast (Ob) lineage in adolescent male and female rats. Briefly, eight-week old male and female Sprague-Dawley rats were administered either vehicle, Scl-Ab (3 or 50mg/kg/week subcutaneously), or human PTH (1-34) (75 μg/kg/day subcutaneously) for 4 or 26 weeks. The 50mg/kg Scl-Ab and the PTH dose were those used in the respective rat lifetime pharmacology studies. Using robust stereological methods, we compared the effects of these agents specifically at the level of the Ob lineage in vertebrae from female rats. Using RUNX2 or nestin immunostaining, location, and morphology, the total number of osteoprogenitor subpopulations, Ob, and lining cells were estimated using the fractionator or proportionator estimators. Density estimates were also calculated referent to total bone surface, total Ob surface, or total marrow volume. Scl-Ab generally effected greater increases in cancellous and cortical bone mass than PTH, correlating with higher bone formation rates (BFR) at 4 weeks in the spine and mid-femur without corresponding increases in bone resorption indices. The increases in vertebral BFR/BS at 4 weeks attenuated with continued treatment to a greater extent with Scl-Ab than with PTH. At 4 weeks, both Scl-Ab and PTH effected equivalent increases in total Ob number (Ob.N). Ob density on the formative surfaces (Ob.N/Ob.S) remained similar across groups while mineral apposition rate (MAR) was significantly higher with Scl-Ab at week 4, reflecting an increase in individual Ob vigor relative to vehicle and PTH. After 26 weeks, Scl-Ab maintained BFR/BS with fewer Ob and lower Ob.N/Ob.S by increasing the Ob footprint (bone surface area occupied by an Ob) and increasing MAR, compared with PTH. The lower Ob.N and Ob.N/Ob.S with Scl-Ab at 26 weeks were associated with decreased osteoprogenitor numbers compared with both vehicle and PTH, an effect not evident at week 4. Osteoprogenitor numbers were generally positively correlated with Ob.N across groups and timepoints, suggesting dynamic coordination between the progenitor and Ob populations. The time-dependent reductions in subpopulations of the Ob lineage with Scl-Ab may be integral to the greater attenuation or self-regulation of bone formation observed at the vertebra, as PTH required more Ob at the formative site with correlative increased numbers of progenitors compared with Scl-Ab indicating potentially greater stimulus for progenitor pool proliferation or differentiation.
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Affiliation(s)
- Michael S Ominsky
- Department of Metabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | | | - Gwyneth Van
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - David Cordover
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Efrain Pacheco
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Emily Frazier
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Linda Cherepow
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Marnie Higgins-Garn
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - J Ignacio Aguirre
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Thomas J Wronski
- Department of Physiological Sciences, University of Florida, Gainesville, FL, USA
| | - Marina Stolina
- Department of Metabolic Disorders, Amgen Inc., Thousand Oaks, CA, USA
| | - Lei Zhou
- Global Biostatistical Science, Amgen Inc., Thousand Oaks, CA, USA
| | - Ian Pyrah
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA
| | - Rogely Waite Boyce
- Department of Comparative Biology and Safety Sciences, Amgen Inc., Thousand Oaks, CA, USA.
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20
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Wu Y, Xia L, Zhou Y, Xu Y, Jiang X. Icariin induces osteogenic differentiation of bone mesenchymal stem cells in a MAPK-dependent manner. Cell Prolif 2015; 48:375-84. [PMID: 25867119 DOI: 10.1111/cpr.12185] [Citation(s) in RCA: 92] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Accepted: 12/14/2014] [Indexed: 01/13/2023] Open
Abstract
OBJECTIVES Icariin, a flavonoid isolated from Epimedium pubescens, has previously been identified to exert beneficial effects on preventing bone loss and promoting bone regeneration. However, molecular mechanisms for its anabolic action have, up to now, remained largely unknown. MATERIALS AND METHODS Effects of icariin on cell proliferation and osteogenic differentiation of rat bone mesenchymal stem cells (BMSCs) were systematically evaluated. To characterize underlying mechanisms, its effects on mitogen-activated protein kinase (MAPK) signalling pathways were determined. RESULTS Results showed that icariin might not have enhanced effects on cell proliferation. However, it seemed to significantly enhance osteogenic differentiation of BMSCs, demonstrated by increasing alkaline phosphatase (ALP) activity and gene expression of collagen type I (Col I), osteocalcin (OCN) and osteopotin (OPN). It was demonstrated that icariin rapidly phosphorylated extracellular signal-regulated kinase (ERK), p38 kinase and c-Jun N terminal kinase (JNK). Furthermore, icariin-stimulated osteogenic effects on BMSCs were dramatically attenuated by treatment with either specific ERK inhibitor of PD98059, p38 inhibitor of SB202190 or JNK inhibitor SP600125. CONCLUSIONS These results provide a potential mechanism of anabolic activity of icariin on BMSCs involving ERK, p38 and JNK MAPK pathways.
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Affiliation(s)
- Yuqiong Wu
- Department of Prosthodontics, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, China; Oral Bioengineering and Regenerative Medicine Lab, Shanghai Research Institute of Stomatology, Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, 200011, China
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Liu S, Zhu W, Li S, Cui T, Li Z, Zhang B, Li Z, Wu J, Liang X, Lin Z, Shi W. The effect of bovine parathyroid hormone withdrawal on MC3T3-E1 cell proliferation and phosphorus metabolism. PLoS One 2015; 10:e0120402. [PMID: 25775025 PMCID: PMC4361577 DOI: 10.1371/journal.pone.0120402] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Accepted: 01/25/2015] [Indexed: 11/18/2022] Open
Abstract
Hypocalcemia and hypophosphatemia are common complications after parathyroidectomy (PTX). Sudden removal of high circulating levels of parathyroid hormone (PTH) causes decreased osteoclastic resorption resulting in a decreased bone remodeling space. These phenomena are likely due to an increased influx of calcium and phosphorus into bone. However, there are currently no data to support this hypothesis. In this study, we found that PTX significantly reduced levels of PTH, calcium and phosphate. Compared with preoperative levels, after 1 year, postoperative PTH, calcium and phosphate levels were 295.6 ± 173.7 pg/mL (P < 0.05), 86.62 ± 15.98 mg/dL (P < 0.05) and 5.56 ± 2.03 mg/dL (P < 0.05), respectively. We investigated continuous bovine PTH administration as well as withdrawal of bovine PTH stimulation in the mouse osteoblast precursor cell line MC3T3-E1. MC3T3-E1 cells were cultured with continuous bovine PTH treatment for 20 days or with transient bovine PTH treatment for 10 days. High doses of continuous bovine PTH exposure strongly reduced cell proliferation, alkaline phosphatase activity and the number of mineralized calcium nodules. However, withdrawal of bovine PTH (100 ng/mL) significantly increased the number of mineralized calcium nodules and caused a rapid decline in calcium and phosphorus content of culture medium. In conclusion, continuous exposure to bovine PTH inhibited osteoblast differentiation and reduced the formation of mineralized nodules. However, this inhibition was removed and mineralized nodule formation resumed with withdrawal of bovine PTH. According to the results of our clinical examinations and in vitro experiments, we hypothesize that the sudden removal of high levels of PTH may cause an increased influx of calcium and phosphorus into bone after PTX.
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Affiliation(s)
- Shuangxin Liu
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
| | - Weiping Zhu
- Department of Nephrology, the Fifth Affiliated Hospital of Sun Yat-sen University, No.52 Meihua Road, Zhuhai, China
| | - Sijia Li
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
| | - Tongxia Cui
- Department of Nephrology, the Fifth Affiliated Hospital of Sun Yat-sen University, No.52 Meihua Road, Zhuhai, China
| | - Zhonghe Li
- Department of Nephrology, the Fifth Affiliated Hospital of Sun Yat-sen University, No.52 Meihua Road, Zhuhai, China
| | - Bin Zhang
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
| | - Zhuo Li
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
| | - Jianxiong Wu
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
| | - Xinling Liang
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
| | - Zheng Lin
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
| | - Wei Shi
- Department of Nephrology, Guangdong General Hospital, Guangdong Academy of Medical Sciences, 106 Zhongshan No. 2 Road, Guangzhou, China
- * E-mail:
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Guimarães GN, Rodrigues TL, de Souza AP, Line SR, Marques MR. Parathyroid hormone (1-34) modulates odontoblast proliferation and apoptosis via PKA and PKC-dependent pathways. Calcif Tissue Int 2014; 95:275-81. [PMID: 25012507 DOI: 10.1007/s00223-014-9892-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2014] [Accepted: 06/28/2014] [Indexed: 02/04/2023]
Abstract
Parathyroid hormone (PTH) plays a key role in the development and homeostasis of mineralized tissues such as bone and dentine. We have reported that PTH (1-34) administration can increase dentine formation in mice and that this hormone modulates in vitro mineralization of odontoblast-like cells. The purpose of the present study was to investigate whether PTH (1-34) participates in the proliferative and apoptotic signaling of odontoblast-like cells (MDPC23). MDPC23 cells were exposed to 50 ng/ml hPTH (1-34) or vehicle for 1 (P1), 24 (P24), or 48 (P48) hours, and the cell proliferation, apoptosis, and cell number were evaluated. To examine whether changes in the proliferative and apoptotic signaling in response to PTH involve protein kinases A (PKA) and/or C (PKC), MDPC23 cells were exposed to PTH with or without PKC or PKA signaling pathway inhibitors. Overall, the results showed that the PKA pathway acts in response to PTH exposure maintaining levels of cell proliferation, while the PKC pathway is mainly involved for longer exposure to PTH (24 or 48 h), leading to the reduction of cell proliferation and increase of apoptosis. The exposure to PTH reduced the cell number in relation to the control group in a time-dependent manner. In conclusion, PTH modulates odontoblast-like cell proliferative and apoptotic response in a time-dependent manner. Both PKC and PKA pathways participate in PTH-induced modulation in an antagonist mode.
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Affiliation(s)
- Gustavo Narvaes Guimarães
- Department of Morphology, Division of Histology and Embryology, Piracicaba Dental School, University of Campinas, Av. Limeira 901, Caixa Postal 052 CEP, Piracicaba, São Paulo, 13414-903, Brazil
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Chen M, Qiao H, Su Z, Li H, Ping Q, Zong L. Emerging therapeutic targets for osteoporosis treatment. Expert Opin Ther Targets 2014; 18:817-31. [PMID: 24766518 DOI: 10.1517/14728222.2014.912632] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
INTRODUCTION To date, osteoporosis still remains a major public health burden especially for the aging populations. Over the last few decades treatments for osteoporosis have largely focused on anti-resorptive agents represented by bisphosphonates and estrogen therapy that dominated the market. Unsatisfactory efficacy, non-specificity and long-term safety of current therapies necessitate the need for new targets effectively preventing and treating of osteoporosis. AREAS COVERED This review expatiates on the mechanism of osteoporosis occurrence and bone remodeling cycle in detail. New targets of antiresorptive and anabolic agents based on the functions of osteoblasts and osteoclasts as well as associated signaling pathways are outlined. EXPERT OPINION Advanced understanding in the fields of bone remodeling, functions of osteoblasts, osteoclasts and osteocytes associated with osteoporosis occurrence offers the emerging bone-resorptive or bone-formative targets. Currently, molecules involving RANK-RANKL-OPG system and Wnt/β-catenin signaling pathway act as the most promising targets.
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Affiliation(s)
- Minglei Chen
- China Pharmaceutical University, Key Lab of State Natural Medicine, Department of Pharmaceutics , Nanjing 210009 , PR China +86 25 83271092; +86 25 83271317 ; +86 25 83271092; +86 25 83271317 ; ;
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Wu SM, Chiu HC, Chin YT, Lin HY, Chiang CY, Tu HP, Fu MMJ, Fu E. Effects of enamel matrix derivative on the proliferation and osteogenic differentiation of human gingival mesenchymal stem cells. Stem Cell Res Ther 2014; 5:52. [PMID: 24739572 PMCID: PMC4076631 DOI: 10.1186/scrt441] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 01/28/2014] [Indexed: 01/07/2023] Open
Abstract
INTRODUCTION Gingiva-derived mesenchymal stem cells (GMSCs) have recently been harvested and applied for rebuilding lost periodontal tissue. Enamel matrix derivative (EMD) has been used for periodontal regeneration and the formation of new cementum with inserting collagen fibers; however, alveolar bone formation is minimal. Recently, EMD has been shown to enhance the proliferation and mineralization of human bone marrow mesenchymal stem cells. Because the gingival flap is the major component to cover the surgical wound, the effects of EMD on the proliferation and mineralization of GMSCs were evaluated in the present study. METHODS After single cell suspension, the GMSCs were isolated from the connective tissues of human gingiva. The colony forming unit assay of the isolated GMSCs was measured. The expression of stem cell markers was examined by flow cytometry. The cellular telomerase activity was identified by polymerase chain reaction (PCR). The osteogenic, adipogenic and neural differentiations of the GMSCs were further examined. The cell proliferation was determined by MTS assay, while the expression of mRNA and protein for mineralization (including core binding factor alpha, cbfα-1; alkaline phosphatase, ALP; and osteocalcin, OC; ameloblastin, AMBN) were analyzed by real time-PCR, enzyme activity and confocal laser scanning microscopy. RESULTS The cell colonies could be easily identified and the colony forming rates and the telomerase activities increased after passaging. The GMSCs expressed high levels of surface markers for CD73, CD90, and CD105, but showed low expression of STRO-1. Osteogenic, adipogenic and neural differentiations were successfully induced. The proliferation of GMSCs was increased after EMD treatment. ALP mRNA was significantly augmented by treating with EMD for 3 hours, whereas AMBN mRNA was significantly increased at 6 hours after EMD treatment. The gene expression of OC was enhanced at the dose of 100 μg/ml EMD at day 3. Increased protein expression for cbfα-1 at day 3, for ALP at day 5 and 7, and for OC at week 4 after the EMD treatments were observed. CONCLUSIONS Human GMSCs could be successfully isolated and identified. EMD treatments not only induced the proliferation of GMSCs but also enhanced their osteogenic differentiation after induction.
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Abstract
The receptor for parathyroid hormone (PTH) and PTH-related peptide (PTH1R) belongs to the class II G protein-coupled receptor superfamily. The calpain small subunit encoded by the gene Capns1 is the second protein and the first enzyme identified by a yeast two-hybrid screen using the intracellular C-terminal tail of the rat PTH1R. The calpain regulatory small subunit forms a heterodimer with the calpain large catalytic subunit and modulates various cellular functions as a cysteine protease. To investigate a physiological role of the calpain small subunit in cells of the osteoblast lineage, we generated osteoblast-specific Capns1 knockout mouse models and characterized their bone phenotype. Molecular mechanisms by which calpain modulates cell proliferation of the osteoblast lineage were further examined in vitro. Moreover, we utilized the mutant mice as a disease model of osteoporosis accompanied with impaired bone resorptive function and suggested a possible clinical translation of our basic research finding.
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Esbrit P, Alcaraz MJ. Current perspectives on parathyroid hormone (PTH) and PTH-related protein (PTHrP) as bone anabolic therapies. Biochem Pharmacol 2013; 85:1417-23. [PMID: 23500550 DOI: 10.1016/j.bcp.2013.03.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/01/2013] [Accepted: 03/01/2013] [Indexed: 12/19/2022]
Abstract
Osteoporosis is characterized by low bone mineral density and/or poor bone microarchitecture leading to an increased risk of fractures. The skeletal alterations in osteoporosis are a consequence of a relative deficit of bone formation compared to bone resorption. Osteoporosis therapies have mostly relied on antiresorptive drugs. An alternative therapeutic approach for osteoporosis is currently available, based on the intermittent administration of parathyroid hormone (PTH). Bone anabolism caused by PTH therapy is mainly accounted for by the ability of PTH to increase osteoblastogenesis and osteoblast survival. PTH and PTH-related protein (PTHrP)-an abundant local factor in bone- interact with the common PTH type 1 receptor with similar affinities in osteoblasts. Studies mainly in osteoporosis rodent models and limited data in postmenopausal women suggest that N-terminal PTHrP peptides might be considered a promising bone anabolic therapy. In addition, putative osteogenic actions of PTHrP might be ascribed not only to its N-terminal domain but also to its PTH-unrelated C-terminal region. In this review, we discuss the underlying cellular and molecular mechanisms of the anabolic actions of PTH and the similar potential of PTH-related protein (PTHrP) to increase bone mass and improve bone regeneration.
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Affiliation(s)
- Pedro Esbrit
- Laboratorio de Metabolismo Mineral y Óseo, Instituto de Investigación Sanitaria-IIS-Fundación Jiménez Díaz, 28040 Madrid, Spain.
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Ono N, Nakashima K, Schipani E, Hayata T, Ezura Y, Soma K, Kronenberg HM, Noda M. Constitutively active PTH/PTHrP receptor specifically expressed in osteoblasts enhances bone formation induced by bone marrow ablation. J Cell Physiol 2012; 227:408-15. [PMID: 21866553 DOI: 10.1002/jcp.22986] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Bone is maintained by continuous bone formation by osteoblasts provided by proliferation and differentiation of osteoprogenitors. Parathyroid hormone (PTH) activates bone formation, but because of the complexity of cells in the osteoblast lineage, how these osteoprogenitors are regulated by PTH in vivo is incompletely understood. To elucidate how signals by PTH in differentiated osteoblasts regulate osteoprogenitors in vivo, we conducted bone marrow ablation using Col1a1-constitutively active PTH/PTHrP receptor (caPPR) transgenic mice. These mice express caPPR specifically in osteoblasts by using 2.3 kb Col1a1 promoter and showed higher trabecular bone volume under steady-state conditions. In contrast, after bone marrow ablation, stromal cells recruited from bone surface extensively proliferated in the marrow cavity in transgenic mice, compared to limited proliferation in wild-type mice. Whereas de novo bone formation was restricted to the ablated area in wild-type mice, the entire marrow cavity, including not only ablated area but also outside the ablated area, was filled with newly formed bone in transgenic mice. Bone mineral density was significantly increased after ablation in transgenic mice. Bone marrow cell culture in osteogenic medium revealed that alkaline phosphatase-positive area was markedly increased in the cells obtained from transgenic mice. Furthermore, mRNA expression of Wnt-signaling molecules such as LRP5, Wnt7b, and Wnt10b were upregulated after marrow ablation in bone marrow cells of transgenic mice. These results indicate that constitutive activation of PTH/PTHrP receptor in differentiated osteoblasts enhances bone marrow ablation-induced recruitment, proliferation, and differentiation of osteoprogenitors.
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Affiliation(s)
- Noriaki Ono
- Department of Molecular Pharmacology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
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Silva BC, Costa AG, Cusano NE, Kousteni S, Bilezikian JP. Catabolic and anabolic actions of parathyroid hormone on the skeleton. J Endocrinol Invest 2011; 34:801-10. [PMID: 21946081 PMCID: PMC4315330 DOI: 10.3275/7925] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PTH, an 84-amino acid peptide hormone synthesized by the parathyroid glands, is essential for the maintenance of calcium homeostasis.While in its traditional metabolic role, PTH helps to maintain the serum calcium concentration within narrow, normal limits and participates as a determinant of bone remodeling, more specific actions, described as catabolic and anabolic are also well known. Clinically, the catabolic effect of PTH is best represented by primary hyperparathyroidism (PHPT), while the osteoanabolic effect of PTH is best seen when PTH or its biological amino-terminal fragment [PTH(1-34)] is used as a therapy for osteoporosis. These dual functions of PTH are unmasked under very specific pathological (PHPT) or therapeutic conditions. At the cellular level, PTH favors bone resorption, mostly by affecting the receptor activator of nuclear factor κ-B (RANK) ligand (RANKL)-osteoprotegerin- RANK system, leading to an increase in osteoclast formation and activity. Increased bone formation due to PTH therapy is explained best by its ability to enhance osteoblastogenesis and/or osteoblast survival. The PTH-induced bone formation is mediated, in part, by a decrease in SOST/sclerostin expression in osteocytes. This review focuses on the dual anabolic and catabolic actions of PTH on bone, situations where one is enhanced over the other, and the cellular and molecular mechanisms by which these actions are mediated.
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Affiliation(s)
- B C Silva
- Metabolic Bone Diseases Unit, Division of Endocrinology, Department of Medicine, College of Physicians and Surgeons, Columbia University, USA
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Mahalingam CD, Datta T, Patil RV, Kreider J, Bonfil RD, Kirkwood KL, Goldstein SA, Abou-Samra AB, Datta NS. Mitogen-activated protein kinase phosphatase 1 regulates bone mass, osteoblast gene expression, and responsiveness to parathyroid hormone. J Endocrinol 2011; 211:145-56. [PMID: 21852324 PMCID: PMC3783352 DOI: 10.1530/joe-11-0144] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Parathyroid hormone (PTH) signaling via PTH 1 receptor (PTH1R) involves mitogen-activated protein kinase (MAPK) pathways. MAPK phosphatase 1 (MKP1) dephosphorylates and inactivates MAPKs in osteoblasts, the bone-forming cells. We previously showed that PTH1R activation in differentiated osteoblasts upregulates MKP1 and downregulates pERK1/2-MAPK and cyclin D1. In this study, we evaluated the skeletal phenotype of Mkp1 knockout (KO) mice and the effects of PTH in vivo and in vitro. Microcomputed tomography analysis of proximal tibiae and distal femora from 12-week-old Mkp1 KO female mice revealed osteopenic phenotype with significant reduction (8-46%) in bone parameters compared with wild-type (WT) controls. Histomorphometric analysis showed decreased trabecular bone area in KO females. Levels of serum osteocalcin (OCN) were lower and serum tartrate-resistant acid phosphatase 5b (TRAP5b) was higher in KO animals. Treatment of neonatal mice with hPTH (1-34) for 3 weeks showed attenuated anabolic responses in the distal femora of KO mice compared with WT mice. Primary osteoblasts derived from KO mice displayed delayed differentiation determined by alkaline phosphatase activity, and reduced expressions of Ocn and Runx2 genes associated with osteoblast maturation and function. Cells from KO females exhibited attenuated PTH response in mineralized nodule formation in vitro. Remarkably, this observation was correlated with decreased PTH response of matrix Gla protein expression. Expressions of pERK1/2 and cyclin D1 were inhibited dramatically by PTH in differentiated osteoblasts from WT mice but much less in osteoblasts from Mkp1 KO mice. In conclusion, MKP1 is important for bone homeostasis, osteoblast differentiation and skeletal responsiveness to PTH.
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Affiliation(s)
- Chandrika D Mahalingam
- Division of Endocrinology, Department of Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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Conradie MM, Cato ACB, Ferris WF, de Wet H, Horsch K, Hough S. MKP-1 knockout does not prevent glucocorticoid-induced bone disease in mice. Calcif Tissue Int 2011; 89:221-7. [PMID: 21698455 DOI: 10.1007/s00223-011-9509-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2011] [Accepted: 05/06/2011] [Indexed: 11/25/2022]
Abstract
Glucocorticoid-induced osteoporosis (GCOP) is predominantly caused by inhibition of bone formation, resulting from a decrease in osteoblast numbers. Employing mouse (MBA-15.4) and human (MG-63) osteoblast cell lines, we previously found that the glucocorticoid (GC) dexamethasone (Dex) inhibits cellular proliferation as well as activation of the MAPK/ERK signaling pathway, essential for mitogenesis in these cells, and that both these effects could be reversed by the protein tyrosine phosphatase (PTP) inhibitor vanadate. In a rat model of GCOP, the GC-induced changes in bone formation, mass, and strength could be prevented by vanadate cotreatment, suggesting that the GC effects on bone were mediated by one or more PTPs. Employing phosphatase inhibitors, qRT-PCR, Western blotting, and overexpression/knockdown experiments, we concluded that MKP-1 was upregulated by Dex, that this correlated with the dephosphorylation of ERK, and that it largely mediated the in vitro effects of GCs on bone. To confirm the pivotal role of MKP-1 in vivo, we investigated the effects of the GC methylprednisolone on the quantitative bone histology of wild-type (WT) and MKP-1 homozygous knockout (MKP-1(-/-)) mice. In WT mice, static bone histology revealed that GC administration for 28 days decreased osteoid surfaces, volumes, and osteoblast numbers. Dynamic histology, following time-spaced tetracycline labeling, confirmed a significant GC-induced reduction in osteoblast appositional rate and bone formation rate. However, identical results were obtained in MKP-1 knockout mice, suggesting that in these animals upregulation of MKP-1 by GCs cannot be regarded as the sole mediator of the GC effects on bone.
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Affiliation(s)
- Maria M Conradie
- Division of Endocrinology, Department of Medicine, Stellenbosch University, Tygerberg, Cape Town, South Africa.
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Kim BG, Park YJ, Libermann TA, Cho JY. PTH regulates myleoid ELF-1-like factor (MEF)-induced MAB-21-like-1 (MAB21L1) expression through the JNK1 pathway. J Cell Biochem 2011; 112:2051-61. [DOI: 10.1002/jcb.23124] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Kashiwagi A, Fein MJ, Shimada M. Calpain modulates cyclin-dependent kinase inhibitor 1B (p27(Kip1)) in cells of the osteoblast lineage. Calcif Tissue Int 2011; 89:36-42. [PMID: 21544553 PMCID: PMC3111891 DOI: 10.1007/s00223-011-9491-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 04/15/2011] [Indexed: 02/05/2023]
Abstract
The ubiquitously expressed calpains-1 and -2 belong to a family of calcium-dependent intracellular cysteine proteases. Both calpains are heterodimers consisting of a large catalytic subunit and a small regulatory subunit encoded by the gene Capn4. Ablation of the calpain small subunit eliminates calpain activity and leads to embryonic lethality. We previously created osteoblast-specific Capn4 knockout mice to investigate a physiological role for the calpain small subunit in cells of the osteoblast lineage. Deletion of Capn4 reduced trabecular and cortical bone, mainly due to impaired proliferation and differentiation of cells of the osteoblast lineage. To further investigate an underlining mechanism by which osteoblast-specific Capn4 knockout mice develop an osteoporotic bone phenotype, we established osteoblastic cell lines stably expressing either control or Capn4 RNA interference for this study. Capn4 knockdown cells showed reduced cell proliferation, accumulation of total and phosphorylated cyclin-dependent kinase inhibitor 1B (p27(Kip1)) on serine 10, and reduced phosphorylation of retinoblastoma protein on threonine 821. Moreover, ablation of Capn4 increased 27 ( Kip1 ) mRNA levels, likely due to stabilized binding of Akt to protein phosphatase 2A, which presumably results in reduced phosphorylation of Akt on S473 and forkhead Box O (FoxO) 3A on T32. Collectively, calpain regulates cell proliferative function by modulating both transcription and degradation of p27(Kip1) in osteoblasts. In conclusion, calpain is a critical modulator for regulation of p27(Kip1) in cells of the osteoblast lineage.
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Affiliation(s)
| | | | - Masako Shimada
- Address correspondence to: Masako Shimada, MD, Ph.D, Thier 10, 50 Blossom Street, Boston, MA 02114, USA, Phone: 1-(617) 726-3966, Fax: 1-(617) 726-1703,
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Childress P, Philip BK, Robling AG, Bruzzaniti A, Kacena MA, Bivi N, Plotkin LI, Heller A, Bidwell JP. Nmp4/CIZ suppresses the response of bone to anabolic parathyroid hormone by regulating both osteoblasts and osteoclasts. Calcif Tissue Int 2011; 89:74-89. [PMID: 21607813 PMCID: PMC3200195 DOI: 10.1007/s00223-011-9496-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2010] [Accepted: 04/27/2011] [Indexed: 10/18/2022]
Abstract
How parathyroid hormone (PTH) increases bone mass is unclear, but understanding this phenomenon is significant to the improvement of osteoporosis therapy. Nmp4/CIZ is a nucleocytoplasmic shuttling transcriptional repressor that suppresses PTH-induced osteoblast gene expression and hormone-stimulated gains in murine femoral trabecular bone. To further characterize Nmp4/CIZ suppression of hormone-mediated bone growth, we treated 10-week-old Nmp4-knockout (KO) and wild-type (WT) mice with intermittent human PTH(1-34) at 30 μg/kg daily or vehicle, 7 days/week, for 2, 3, or 7 weeks. Null mice treated with hormone (7 weeks) gained more vertebral and tibial cancellous bone than WT animals, paralleling the exaggerated response in the femur. Interestingly, Nmp4/CIZ suppression of this hormone-stimulated bone formation was not apparent during the first 2 weeks of treatment. Consistent with the null mice enhanced PTH-stimulated addition of trabecular bone, these animals exhibited an augmented hormone-induced increase in serum osteocalcin 3 weeks into treatment. Unexpectedly, the Nmp4-KO mice displayed an osteoclast phenotype. Serum C-terminal telopeptide, a marker for bone resorption, was elevated in the null mice, irrespective of treatment. Nmp4-KO bone marrow cultures produced more osteoclasts, which exhibited elevated resorbing activity, compared to WT cultures. The expression of several genes critical to the development of both osteoblasts and osteoclasts was elevated in Nmp4-KO mice at 2 weeks, but not 3 weeks, of hormone exposure. We propose that Nmp4/CIZ dampens PTH-induced improvement of trabecular bone throughout the skeleton by transiently suppressing hormone-stimulated increases in the expression of proteins key to the required enhanced activity and number of both osteoblasts and osteoclasts.
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Affiliation(s)
- Paul Childress
- Department of Anatomy and Cell Biology, Indiana University School of Medicine (IUSM), Medical Science Bldg., Indianapolis, IN 46202, USA
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Parathyroid hormone and the regulation of cell cycle in colon adenocarcinoma cells. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1749-57. [PMID: 21703311 DOI: 10.1016/j.bbamcr.2011.06.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2010] [Revised: 04/27/2011] [Accepted: 06/01/2011] [Indexed: 11/23/2022]
Abstract
Parathyroid hormone (PTH) functions as a major mediator of bone remodeling and as an essential regulator of calcium homeostasis. In this study, we investigated the role of PTH in the regulation of the cell cycle in human colon adenocarcinoma Caco-2 cells. Flow cytometry analysis revealed that PTH (10(-8)M, 12-24h) treatment increases the number of cells in the G0/G1 phase and diminishes the number in both phases S and G2/M. In addition, analysis by Western blot showed that the hormone increases the expression of the inhibitory protein p27Kip1 and diminishes the expression of cyclin D1, cyclin D3 and CDK6. However, the amounts of CDK4, p21Cip1, p15INK4B and p16INK4A were not different in the absence or presence of PTH. Inhibitors of PKC (Ro-318220, bisindolylmaleimide and chelerythine), but not JNK (SP600125) and PP2A (okadaic acid and calyculin A), reversed PTH response in Caco-2 cells. Taken together, our results suggest that PTH induces G0/G1 phase arrest of Caco-2 intestinal cells and changes the expression of proteins involved in cell cycle regulation via the PKC signaling pathway.
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Guo ZY, Hao XH, Tan FF, Pei X, Shang LM, Jiang XL, Yang F. The elements of human cyclin D1 promoter and regulation involved. Clin Epigenetics 2011; 2:63-76. [PMID: 22704330 PMCID: PMC3365593 DOI: 10.1007/s13148-010-0018-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2010] [Accepted: 12/07/2010] [Indexed: 02/07/2023] Open
Abstract
Cyclin D1 is a cell cycle machine, a sensor of extracellular signals and plays an important role in G1-S phase progression. The human cyclin D1 promoter contains multiple transcription factor binding sites such as AP-1, NF-қB, E2F, Oct-1, and so on. The extracellular signals functions through the signal transduction pathways converging at the binding sites to active or inhibit the promoter activity and regulate the cell cycle progression. Different signal transduction pathways regulate the promoter at different time to get the correct cell cycle switch. Disorder regulation or special extracellular stimuli can result in cell cycle out of control through the promoter activity regulation. Epigenetic modifications such as DNA methylation and histone acetylation may involved in cyclin D1 transcriptional regulation.
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Affiliation(s)
- Zhi-Yi Guo
- Experimental and Research Center, Hebei United University, № 57 JianShe South Road, TangShan, Hebei 063000 People's Republic of China
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Guo Y, Yuan W, Wang L, Shang M, Peng Y. Parathyroid hormone-potentiated connective tissue growth factor expression in human renal proximal tubular cells through activating the MAPK and NF-kappaB signalling pathways. Nephrol Dial Transplant 2010; 26:839-47. [PMID: 20810452 DOI: 10.1093/ndt/gfq521] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Secondary hyperparathyroidism is a universal complication of chronic renal diseases. One of the pathological consequences of hyperparathyroidism is impairment of the renal interstitium and tubules. However, the molecular mechanism of renal tubular interstitial impairment induced by parathyroid hormone (PTH) remains unclear. Enhanced and prolonged expression of connective tissue growth factor (CTGF) has been associated with fibrosis and inflammation in the kidney. The purpose of this study was to investigate the effects of PTH on CTGF expression patterns in human proximal tubular cell line-HK-2 cells. METHODS We treated cells with various concentrations of PTH for the indicated periods of time in the presence or absence of the mitogen-activated protein kinase (MAPK) inhibitor (PD98059) or the NF-κB inhibitor (PDTC). RESULTS Quantitative real-time RT-PCR analysis revealed that PTH at a concentration of 10(-12)-10(-10) M increased the mRNA levels of CTGF, which was similar to the trends of CTGF protein levels detected by immunoblotting assay. Our data clearly show the ability of human proximal tubular HK-2 cells to produce CTGF after the treatment with PTH. In addition, we showed that PTH induced the phosphorylation of MAPK p42 and p44, and increased NF-κB-binding activities in the PTH-treated cells. Moreover, both PD98059 and PDTC inhibited the effect of PTH on the expression of CTGF, which strongly suggests that these pathways play important roles in the PTH-induced CTGF upregulation in renal tubular cells. CONCLUSIONS Our results indicated for the first time that PTH may enhance the expression of CTGF in human kidney proximal tubular cells, suggesting that PTH may play an important role in the fibrotic and inflammatory process that is a hallmark for progression of chronic kidney disease.
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Affiliation(s)
- Yunshan Guo
- Department of Nephrology, General Hospital of Jinan Military Jinan, Shandong, China
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Sikon A, Batur P. Profile of teriparatide in the management of postmenopausal osteoporosis. Int J Womens Health 2010; 2:37-44. [PMID: 21072295 PMCID: PMC2971740 DOI: 10.2147/ijwh.s4919] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Indexed: 01/12/2023] Open
Abstract
One out of every 2 women within postmenopause are at risk of fracture due to osteoporosis. Fortunately, a growing arsenal of therapies is becoming available to treat this disease and prevent fracture. A new class of anabolic agents has emerged within the last decade that brought with it a new concept in osteoporosis therapy: building new stronger bone rather than simply inhibiting bone turnover. Evidence is accumulating to understand how to best utilize these new agents, and which patients benefit most. This article will review the effectiveness, risks, timing and clinical uses of teriparatide in postmenopausal osteoporosis.
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Affiliation(s)
- Andrea Sikon
- Cleveland Clinic Lerner COM, Cleveland Clinic, Cleveland, OH, USA
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Roy Choudhury D, Small C, Wang Y, Mueller PR, Rebel VI, Griswold MD, McCarrey JR. Microarray-based analysis of cell-cycle gene expression during spermatogenesis in the mouse. Biol Reprod 2010; 83:663-75. [PMID: 20631398 DOI: 10.1095/biolreprod.110.084889] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Mammalian spermatogenesis is a continuum of cellular differentiation in a lineage that features three principal stages: 1) a mitotically active stage in spermatogonia, 2) a meiotic stage in spermatocytes, and 3) a postreplicative stage in spermatids. We used a microarray-based approach to identify changes in expression of cell-cycle genes that distinguish 1) mitotic type A spermatogonia from meiotic pachytene spermatocytes and 2) pachytene spermatocytes from postreplicative round spermatids. We detected expression of 550 genes related to cell-cycle function in one or more of these cell types. Although a majority of these genes were expressed during all three stages of spermatogenesis, we observed dramatic changes in levels of individual transcripts between mitotic spermatogonia and meiotic spermatocytes and between meiotic spermatocytes and postreplicative spermatids. Our results suggest that distinct cell-cycle gene regulatory networks or subnetworks are associated with each phase of the cell cycle in each spermatogenic cell type. In addition, we observed expression of different members of certain cell-cycle gene families in each of the three spermatogenic cell types investigated. Finally, we report expression of 221 cell-cycle genes that have not previously been annotated as part of the cell cycle network expressed during spermatogenesis, including eight novel genes that appear to be testis-specific.
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Datta NS, Kolailat R, Fite A, Pettway G, Abou-Samra AB. Distinct roles for mitogen-activated protein kinase phosphatase-1 (MKP-1) and ERK-MAPK in PTH1R signaling during osteoblast proliferation and differentiation. Cell Signal 2010; 22:457-66. [PMID: 19892016 DOI: 10.1016/j.cellsig.2009.10.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2009] [Revised: 10/27/2009] [Accepted: 10/27/2009] [Indexed: 12/22/2022]
Abstract
Parathyroid hormone (PTH) and PTH-related protein (PTHrP) activate one single receptor (PTH1R) which mediates catabolic and anabolic actions in the bone. Activation of PTH1R modulates multiple intracellular signaling responses. We previously reported that PTH and PTHrP down-regulate pERK1/2 and cyclin D1 in differentiated osteoblasts. In this study we investigate the role of MAPK phosphatase-1 (MKP-1) in PTHrP regulation of ERK1/2 activity in relation to osteoblast proliferation, differentiation and bone formation. Here we show that PTHrP increases MKP-1 expression in differentiated osteoblastic MC3T3-E1 cells, primary cultures of differentiated bone marrow stromal cells (BMSCs) and calvarial osteoblasts. PTHrP had no effect on MKP-1 expression in proliferating osteoblastic cells. Overexpression of MKP-1 in MC-4 cells inhibited osteoblastic cell proliferation. Cell extracts from differentiated MC-4 cells treated with PTHrP inactivate/dephosphorylate pERK1/2 in vitro; immunodepletion of MKP-1 blocked the ability of the extract to dephosphorylate pERK1/2; these data indicate that MKP-1 is involved in PTHrP-induced pERK1/2 dephosphorylation in the differentiated osteoblastic cells. PTHrP regulation of MKP-1 expression is partially dependent on PKA and PKC pathways. Treatment of nude mice, bearing ectopic ossicles, with intermittent PTH for 3weeks, up-regulated MKP-1 and osteocalcin, a bone formation marker, with an increase in bone formation. These data indicate that PTH and PTHrP increase MKP-1 expression in differentiated osteoblasts; and that MKP-1 induces growth arrest of osteoblasts, via inactivating pERK1/2 and down-regulating cyclin D1; and identify MKP-1 as a possible mediator of the anabolic actions of PTH1R in mature osteoblasts.
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Affiliation(s)
- Nabanita S Datta
- Wayne State University School of Medicine, Department Internal Medicine, Division Endocrinology, Detroit, MI 48201, USA.
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Lai LP, Mitchell J. Parathyroid hormone inhibits phosphorylation of mitogen-activated protein kinase (MAPK) ERK1/2 through inhibition of c-Raf and activation of MKP-1 in osteoblastic cells. Cell Biochem Funct 2009; 27:269-75. [PMID: 19384851 DOI: 10.1002/cbf.1568] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Parathyroid hormone (PTH) regulation of mitogen-activated protein kinases (MAPK) ERK1/2 contributes to PTH regulation of osteoblast growth and apoptosis. We investigated the mechanisms by which PTH inhibits ERK1/2 activity in osteoblastic UMR 106-01 cells. Treatment with PTH significantly inhibited phosphorylated ERK1/2 between 5 and 60 min. Transient transfection of cells with a cDNA encoding MAPK phosphatase-1 (MKP-1) resulted in 30-40% inhibition of pERK1/2; however MKP-1 protein levels were only significantly stimulated by PTH after 30 mins, suggesting another mechanism for the early phase of pERK1/2 inhibition. The active upstream kinase c-Raf phosphorylation at serine 338 (ser(338)) was significantly inhibited by PTH treatment within 5 min and transfection of the cells with constitutively-active c-Raf blocked PTH inhibition of pERK1/2. Inhibition of pERK1/2 and phosphor-c-Raf were seen when cells were treated with PTH(1-34) or PTH(1-31) analogues that stimulate cAMP, but not with PTH(3-34), PTH(7-34) or PTH(18-48) that do not stimulate cAMP. Stimulation of the cells with forskolin or 8BrcAMP also inhibited pERK1/2 and c-Raf.p338. Our results suggest that rapid PTH inhibition of ERK1/2 activity is mediated by PKA dependent inhibition of c-Raf activity and that stimulation of MKP-1 may contribute to maintaining pERK1/2 inhibition over prolonged time.
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Affiliation(s)
- Lick Pui Lai
- Department of Pharmacology and Toxicology, University of Toronto, 1 King's College Circle, Room 4342, Toronto, Ontario, Canada M5S 1A8, Canada
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Abstract
The striking clinical benefit of PTH in osteoporosis began a new era of skeletal anabolic agents. Several studies have been performed, new studies are emerging out and yet controversies remain on PTH anabolic action in bone. This review focuses on the molecular aspects of PTH and PTHrP signaling in light of old players and recent advances in understanding the control of osteoblast proliferation, differentiation and function.
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Affiliation(s)
- Nabanita S Datta
- Division Endocrinology, Department Internal Medicine, Wayne State University School of Medicine, 421 East Canfield Avenue, Detroit, Michigan 48201, USA.
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Ruiz C, Abril N, Tarín JJ, García-Pérez MA, Cano A. The new frontier of bone formation: a breakthrough in postmenopausal osteoporosis? Climacteric 2009; 12:286-300. [PMID: 19415543 DOI: 10.1080/13697130902736939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
OBJECTIVE Osteoporosis is a chronic disease that accelerates after menopause in many women. Most of the pharmacologic attempts to control the disease, such as hormone therapy, have emphasized the constraint of bone resorption. Since recent years have witnessed important advances in the field of bone formation, this review aims to update the present knowledge on the mechanisms affecting osteoblastogenesis and on the therapeutic results achieved by recently approved drugs. METHOD We sought peer-reviewed, full-length basic and clinical articles published between 1995 and May 2008 using a PubMed search strategy, with the terms osteoporosis and osteoblast, osteoporosis and strontium ranelate, and osteoporosis and parathyroid hormone (PTH). This search was further supplemented by a hand-search of reference lists of selected review papers. After crossing-cleaning the reference lists, some 800 articles were selected. Articles on regulators of osteoblast differentiation and function, together with well-designed clinical studies, were surveyed. RESULTS A complex network of systemic and local factors regulates osteoblastogenesis. Advances in fracture protection have been published in clinical studies with PTH. Some investigators claim an anabolic effect for strontium ranelate, which also confers protection against fracture. CONCLUSION The control of bone formation offers new clinical potential. Stimulation of bone formation by PTH has translated into fracture protection. The action of strontium ranelate has been claimed to be mediated by some level of bone formation, but this hypothesis still needs clarification.
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Affiliation(s)
- C Ruiz
- Department of Obstetrics and Gynecology, Hospital Clínico Universitario, Valencia, Spain
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Sabbieti MG, Agas D, Xiao L, Marchetti L, Coffin JD, Doetschman T, Hurley MM. Endogenous FGF-2 is critically important in PTH anabolic effects on bone. J Cell Physiol 2009; 219:143-51. [PMID: 19107841 DOI: 10.1002/jcp.21661] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Parathyroid hormone (PTH) increases fibroblast growth factor receptor-1 (FGFR1) and fibroblast growth factor-2 (FGF-2) expression in osteoblasts and the anabolic response to PTH is reduced in Fgf2-/- mice. This study examined whether candidate factors implicated in the anabolic response to PTH were modulated in Fgf2-/- osteoblasts. PTH increased Runx-2 protein expression in Fgf2+/+ but not Fgf2-/- osteoblasts. By immunocytochemistry, PTH treatment induced nuclear accumulation of Runx-2 only in Fgf2+/+ osteoblasts. PTH and FGF-2 regulate Runx-2 via activation of the cAMP response element binding proteins (CREBs). Western blot time course studies showed that PTH increased phospho-CREB within 15 min that was sustained for 24 h in Fgf2+/+ but had no effect in Fgf2-/- osteoblasts. Silencing of FGF-2 in Fgf2+/+ osteoblasts blocked the stimulatory effect of PTH on Runx-2 and CREBs phosphorylation. Studies of the effects of PTH on proteins involved in osteoblast precursor proliferation and apoptosis showed that PTH increased cyclinD1-cdk4/6 protein in Fgf2+/+ but not Fgf2-/- osteoblasts. Interestingly, PTH increased the cell cycle inhibitor p21/waf1 in Fgf2-/- osteoblasts. PTH increased Bcl-2/Bax protein ratio in Fgf2+/+ but not Fgf2-/- osteoblasts. In addition PTH increased cell viability in Fgf2+/+ but not Fgf2-/- osteoblasts. These data suggest that endogenous FGF-2 is important in PTH effects on osteoblast proliferation, differentiation, and apoptosis. Reduced expression of these factors may contribute to the reduced anabolic response to PTH in the Fgf2-/- mice. Our results strongly indicate that the anabolic PTH effect is dependent in part on FGF-2 expression.
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Affiliation(s)
- Maria Giovanna Sabbieti
- Department of Comparative Morphology and Biochemistry, University of Camerino, Camerino (MC), Italy
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Jilka RL, O'Brien CA, Ali AA, Roberson PK, Weinstein RS, Manolagas SC. Intermittent PTH stimulates periosteal bone formation by actions on post-mitotic preosteoblasts. Bone 2009; 44:275-86. [PMID: 19010455 PMCID: PMC2655212 DOI: 10.1016/j.bone.2008.10.037] [Citation(s) in RCA: 100] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Accepted: 10/01/2008] [Indexed: 01/04/2023]
Abstract
Intermittent administration of parathyroid hormone (PTH) stimulates bone formation on the surface of cancellous and periosteal bone by increasing the number of osteoblasts. Previous studies of ours in mice demonstrated that intermittent PTH increases cancellous osteoblast number at least in part by attenuating osteoblast apoptosis, but the mechanism responsible for the anabolic effect of the hormone on periosteal bone is unknown. We report that daily injections of 100 ng/g of PTH(1-34) to 4-6 month old mice increased the number of osteoblasts on the periosteum of lumbar vertebrae by 2-3 fold as early as after 2 days. However, the prevalence of apoptotic periosteal osteoblasts was only 0.2% in vehicle treated animals, which is approximately 20-fold lower than is the case for cancellous osteoblasts. Moreover, PTH did not have a discernable effect on periosteal osteoblast apoptosis. Administration of BrdU for 4 days failed to label periosteal osteoblasts under either basal conditions or following administration of PTH. Cancellous osteoblasts, on the other hand, were labeled under basal conditions, but PTH did not increase the percentage of BrdU-positive cells. Thus, intermittent PTH does not increase cancellous or periosteal osteoblast number by stimulating the proliferation of osteoblast progenitors. Consistent with high turnover of cancellous osteoblasts as compared to that of periosteal osteoblasts, ganciclovir-induced ablation of replicating osteoblast progenitors in mice expressing thymidine kinase under the control of the 3.6 kb rat Col1A1 promoter resulted in disappearance of osteoblasts from cancellous bone over a 7-14 day period, whereas periosteal osteoblasts were unaffected. However, 14 days of pre-treatment with ganciclovir prevented PTH anabolism on periosteal bone. We conclude that in cancellous bone, attenuation of osteoblast apoptosis by PTH increases osteoblast number because their rate of apoptosis is high, making this effect of the hormone profound. However, in periosteal bone where the rate of osteoblast apoptosis is low, PTH must exert pro-differentiating and/or pro-survival effects on post-mitotic pre-osteoblasts. Targeting the latter cells is an effective mechanism for increasing osteoblast number in periosteal bone where the production of osteoblasts from replicating progenitors is slow.
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Affiliation(s)
- Robert L Jilka
- Division of Endocrinology and Metabolism, Center for Osteoporosis and Metabolic Bone Diseases, Central Arkansas Veterans Healthcare System, Slot 587, University of Arkansas for Medical Sciences, 4301 W. Markham, Little Rock, AR, USA.
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Ogita M, Rached MT, Dworakowski E, Bilezikian JP, Kousteni S. Differentiation and proliferation of periosteal osteoblast progenitors are differentially regulated by estrogens and intermittent parathyroid hormone administration. Endocrinology 2008; 149:5713-23. [PMID: 18617606 PMCID: PMC2584601 DOI: 10.1210/en.2008-0369] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The periosteum is now widely recognized as a homeostatic and therapeutic target for actions of sex steroids and intermittent PTH administration. The mechanisms by which estrogens suppress but PTH promotes periosteal expansion are not known. In this report, we show that intermittent PTH(1-34) promotes differentiation of periosteal osteoblast precursors as evidenced by the stimulation of the expression or activity of alkaline phosphatase as well as of targets of the bone morphogenetic protein 2 (BMP-2) and Wnt pathways. In contrast, 17beta-estradiol (E2) had no effect by itself. However, it attenuated PTH- or BMP-2-induced differentiation of primary periosteal osteoblast progenitors. Administration of intermittent PTH to ovariectomized mice induced rapid phosphorylation of the BMP-2 target Smad1/5/8 in the periosteum. A replacement dose of E2 had no effect by itself but suppressed PTH-induced phosphorylation of Smad1/5/8. In contrast to its effects to stimulate periosteal osteoblast differentiation, PTH promoted and subsequently suppressed proliferation of periosteal osteoblast progenitors in vitro and in vivo. E2 promoted proliferation and attenuated the antiproliferative effect of PTH. Both hormones protected periosteal osteoblasts from apoptosis induced by various proapoptotic agents. These observations suggest that the different effects of PTH and estrogens on the periosteum result from opposing actions on the recruitment of early periosteal osteoblast progenitors. Intermittent PTH promotes osteoblast differentiation from periosteum-derived mesenchymal progenitors through ERK-, BMP-, and Wnt-dependent signaling pathways. Estrogens promote proliferation of early osteoblast progenitors but inhibit their differentiation by osteogenic agents such as PTH or BMP-2.
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Affiliation(s)
- Mami Ogita
- Department of Medicine, Columbia University, New York, New York 10032, USA
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46
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Abstract
Continuous exposure to parathyroid hormone (PTH) is associated with catabolic effects, whereas intermittent exposure to low doses of PTH is associated with anabolic effects. By controlling osteoblast function, PTH increases bone formation on cancellous, endocortical, and periosteal bone surfaces. In general, PTH does not affect the replication of uncommitted osteoblast progenitors but suppresses proliferation of committed osteoprogenitors. Intermittent PTH promotes osteoblast differentiation, in part, by its ability to promote exit from the cell cycle, to activate Wnt signaling in osteoblasts, and to inhibit the Wnt antagonist sclerostin in osteocytes. Insulin-like growth factor-1 is also required for the actions of PTH to increase osteoblast numbers. Intermittent PTH prolongs osteoblast survival in rodents by mechanisms that involve activation and proteolytic degradation of Runx2. PTH's ability to orchestrate a dynamic range of signaling cascades that determine osteoblast fate may explain both its catabolic and beneficial actions on the skeleton.
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Affiliation(s)
- Stavroula Kousteni
- Department of Medicine, College of Physicians and Surgeons, Columbia University, 630 West 168th Street, New York, NY 10032, USA
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Anabolic effects of PTH in cyclooxygenase-2 knockout osteoblasts in vitro. Biochem Biophys Res Commun 2008; 372:536-41. [PMID: 18501188 DOI: 10.1016/j.bbrc.2008.05.050] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2008] [Accepted: 05/11/2008] [Indexed: 01/20/2023]
Abstract
PTH is a potent bone anabolic agent in vivo but anabolic effects on osteoblast differentiation in vitro are difficult to demonstrate. This study examined the role of cyclooxygenase (COX)-2 and prostaglandin (PG) production in the effects of PTH on osteoblast differentiation in vitro using marrow stromal cell (MSC) and calvarial osteoblast (COB) cultures from COX-2 knockout (KO) and wild type (WT) mice. Cells were treated with PTH (10 nM) or vehicle throughout culture. Alkaline phosphatase (ALP) and osteocalcin (OCN) mRNA levels were measured at days 14 and 21, respectively, and mineralization at day 21. cAMP concentrations were measured in the presence of a phosphodiesterase inhibitor. PTH did not stimulate differentiation in cultures from WT mice but significantly increased ALP and OCN mRNA expression 6- to 7-fold in KO MSC cultures and 2- to 4-fold in KO COB cultures. PTH also increased mineralization in both KO MSC and COB cultures. Effects in KO cells were mimicked in WT MSC cultures treated with NS-398, an inhibitor of COX-2 activity. PTH increased cAMP concentrations similarly in WT and KO COBs. Differential gene responses to PTH in COX-2 KO COBs relative to WT COBs included greater fold-increases in the cAMP-mediated early response genes, c-fos and Nr4a2; increased IGF-1 mRNA expression; and decreased mRNA expression of MAP kinase phosphatase-1. PTH inhibited SOST mRNA expression 91% in COX-2 KO MSC cultures compared to 67% in WT cultures. We conclude that endogenous PGs inhibit the anabolic responses to PTH in vitro, possibly by desensitizing cAMP pathways.
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Khosla S, Westendorf JJ, Oursler MJ. Building bone to reverse osteoporosis and repair fractures. J Clin Invest 2008; 118:421-8. [PMID: 18246192 DOI: 10.1172/jci33612] [Citation(s) in RCA: 293] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
An important, unfilled clinical need is the development of new approaches to improve fracture healing and to treat osteoporosis by increasing bone mass. Recombinant forms of bone morphogenetic protein 2 (BMP2) and BMP7 are FDA approved to promote spinal fusion and fracture healing, respectively, and the first FDA-approved anabolic drug for osteoporosis, parathyroid hormone, increases bone mass when administered intermittently but can only be given to patients in the US for two years. As we discuss here, the tremendous explosion over the last two decades in our fundamental understanding of the mechanisms of bone remodeling has led to the prospect of mechanism-based anabolic therapies for bone disorders.
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Affiliation(s)
- Sundeep Khosla
- Endocrine Research Unit, College of Medicine, Mayo Clinic, Rochester, Minnesota, USA
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49
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Somjen D, Tordjman K, Katzburg S, Knoll E, Sharon O, Limor R, Naidich M, Naor Z, Hendel D, Stern N. Lipoxygenase metabolites are mediators of PTH-dependent human osteoblast growth. Bone 2008; 42:491-7. [PMID: 18187376 DOI: 10.1016/j.bone.2007.11.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/02/2007] [Revised: 11/08/2007] [Accepted: 11/13/2007] [Indexed: 10/22/2022]
Abstract
PTH-induced osteoblast proliferation may contribute to its anabolic effects in bone. Since PTH-dependent osteoblast-like cell (Ob) growth is mediated via protein kinase C (PKC) and MAP kinase-kinase (MEK) and since lipoxygenase (LO) products activate PKC in a number of cell types, we assessed the expression of LO pathways in primary human cultured Ob. Ob from pre- or post-menopausal women were cultured and were treated with PTH and assayed for the expression of 12-LO and both type I and type II 15-LO mRNA and for the release their enzymatic products, 12- and 15-hydroxyeicosatetraenoic acid (HETE). Cells were also treated with PTH for stimulation DNA synthesis. First, Ob express platelet type- 12-LO and both type I and type II 15-LO mRNA and release their enzymatic products, 12- and 15-hydroxyeicosatetraenoic acid (HETE). Second, in female Ob, PTH induced a rapid increase in 12-HETE (50 fold increase) and 15-HETE (80 fold increase) and increased the expression of 12-LO mRNA but not of the two isoforms of 15-LO. PTH as well as 12 and 15-HETE stimulated DNA synthesis in Ob. The LO inhibitor baicalein inhibited PTH-stimulated DNA synthesis, which was reversed in the presence of either 12- or 15-HETE. A PKC inhibitor (bisindolylmaleimide I) as well as a MEK inhibitor (PD 98059) completely inhibited the stimulation of DNA synthesis by PTH, 12-HETE and the combination of PTH and 12-HETE. In contrast, 15-HETE-induced DNA synthesis was not abolished by these inhibitors. Further, 15-HETE partially restored the stimulatory effect of PTH on DNA synthesis in cells treated with PKC or MEK inhibitors. Finally, PTH- induced ERK1/2 phosphorylation, was blocked by a MEK inhibitor. These results demonstrate a novel mechanism of PTH-induced human bone cell proliferation operating through LO enzymes.
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Affiliation(s)
- Dalia Somjen
- Institute of Endocrinology, Metabolism and Hypertension, Tel-Aviv Sourasky Medical Center, Tel-Aviv University, Tel-Aviv 64239, Israel
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50
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Li X, Qin L, Bergenstock M, Bevelock LM, Novack DV, Partridge NC. Parathyroid Hormone Stimulates Osteoblastic Expression of MCP-1 to Recruit and Increase the Fusion of Pre/Osteoclasts. J Biol Chem 2007; 282:33098-106. [PMID: 17690108 DOI: 10.1074/jbc.m611781200] [Citation(s) in RCA: 143] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The clinical findings that alendronate blunted the anabolic effect of human parathyroid hormone (PTH) on bone formation suggest that active resorption is involved and enhances the anabolic effect. PTH signals via its receptor on the osteoblast membrane, and osteoclasts are impacted indirectly via the products of osteoblasts. Microarray with RNA from rats injected with human PTH or vehicle showed a strong association between the stimulation of monocyte chemoattractant protein-1 (MCP-1) and the anabolic effects of PTH. PTH rapidly and dramatically stimulated MCP-1 mRNA in the femora of rats receiving daily injections of PTH or in primary osteoblastic and UMR 106-01 cells. The stimulation of MCP-1 mRNA was dose-dependent and a primary response to PTH signaling via the cAMP-dependent protein kinase pathway in vitro. Studies with the mouse monocyte cell line RAW 264.7 and mouse bone marrow proved that osteoblastic MCP-1 can potently recruit osteoclast monocyte precursors and facilitate receptor activator of NF-kappaB ligand-induced osteoclastogenesis and, in particular, enhanced fusion. Our model suggests that PTH-induced osteoblastic expression of MCP-1 is involved in recruitment and differentiation at the stage of multinucleation of osteoclast precursors. This information provides a rationale for increased osteoclast activity in the anabolic effects of PTH in addition to receptor activator of NF-kappaB ligand stimulation to initiate greater bone remodeling.
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Affiliation(s)
- Xin Li
- Department of Physiology and Biophysics, University of Medicine and Dentistry of New Jersey-Robert Wood Johnson Medical School, 675 Hoes Lane, Piscataway, NJ 08854, USA
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