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Donat A, Knapstein PR, Jiang S, Baranowsky A, Ballhause TM, Frosch KH, Keller J. Glucose Metabolism in Osteoblasts in Healthy and Pathophysiological Conditions. Int J Mol Sci 2021; 22:ijms22084120. [PMID: 33923498 PMCID: PMC8073638 DOI: 10.3390/ijms22084120] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/11/2021] [Accepted: 04/14/2021] [Indexed: 01/01/2023] Open
Abstract
Bone tissue in vertebrates is essential to performing movements, to protecting internal organs and to regulating calcium homeostasis. Moreover, bone has also been suggested to contribute to whole-body physiology as an endocrine organ, affecting male fertility; brain development and cognition; and glucose metabolism. A main determinant of bone quality is the constant remodeling carried out by osteoblasts and osteoclasts, a process consuming vast amounts of energy. In turn, clinical conditions associated with impaired glucose metabolism, including type I and type II diabetes and anorexia nervosa, are associated with impaired bone turnover. As osteoblasts are required for collagen synthesis and matrix mineralization, they represent one of the most important targets for pharmacological augmentation of bone mass. To fulfill their function, osteoblasts primarily utilize glucose through aerobic glycolysis, a process which is regulated by various molecular switches and generates adenosine triphosphate rapidly. In this regard, researchers have been investigating the complex processes of energy utilization in osteoblasts in recent years, not only to improve bone turnover in metabolic disease, but also to identify novel treatment options for primary bone diseases. This review focuses on the metabolism of glucose in osteoblasts in physiological and pathophysiological conditions.
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Stegen S, Devignes CS, Torrekens S, Van Looveren R, Carmeliet P, Carmeliet G. Glutamine Metabolism in Osteoprogenitors Is Required for Bone Mass Accrual and PTH-Induced Bone Anabolism in Male Mice. J Bone Miner Res 2021; 36:604-616. [PMID: 33253422 DOI: 10.1002/jbmr.4219] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2020] [Revised: 11/16/2020] [Accepted: 11/19/2020] [Indexed: 12/19/2022]
Abstract
Skeletal homeostasis critically depends on the proper anabolic functioning of osteolineage cells. Proliferation and matrix synthesis are highly demanding in terms of biosynthesis and bioenergetics, but the nutritional requirements that support these processes in bone-forming cells are not fully understood. Here, we show that glutamine metabolism is a major determinant of osteoprogenitor function during bone mass accrual. Genetic inactivation of the rate-limiting enzyme glutaminase 1 (GLS1) results in decreased postnatal bone mass, caused by impaired biosynthesis and cell survival. Mechanistically, we uncovered that GLS1-mediated glutamine catabolism supports nucleotide and amino acid synthesis, required for proliferation and matrix production. In addition, glutamine-derived glutathione prevents accumulation of reactive oxygen species and thereby safeguards cell viability. The pro-anabolic role of glutamine metabolism was further underscored in a model of parathyroid hormone (PTH)-induced bone formation. PTH administration increases glutamine uptake and catabolism, and GLS1 deletion fully blunts the PTH-induced osteoanabolic response. Taken together, our findings indicate that glutamine metabolism in osteoprogenitors is indispensable for bone formation. © 2020 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Steve Stegen
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism, and Ageing, KU Leuven, Leuven, Belgium
| | - Claire-Sophie Devignes
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism, and Ageing, KU Leuven, Leuven, Belgium
| | - Sophie Torrekens
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism, and Ageing, KU Leuven, Leuven, Belgium
| | - Riet Van Looveren
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism, and Ageing, KU Leuven, Leuven, Belgium
| | - Peter Carmeliet
- Laboratory of Angiogenesis and Vascular Metabolism, VIB Center for Cancer Biology, Leuven, Belgium.,Laboratory of Angiogenesis and Vascular Metabolism, Department of Oncology and Leuven Cancer Institute, KU Leuven, Leuven, Belgium.,State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, China
| | - Geert Carmeliet
- Laboratory of Clinical and Experimental Endocrinology, Department of Chronic Diseases, Metabolism, and Ageing, KU Leuven, Leuven, Belgium
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Le PT, Liu H, Alabdulaaly L, Vegting Y, Calle IL, Gori F, Lanske B, Baron R, Rosen CJ. The role of Zfp467 in mediating the pro-osteogenic and anti-adipogenic effects on bone and bone marrow niche. Bone 2021; 144:115832. [PMID: 33359894 PMCID: PMC8175945 DOI: 10.1016/j.bone.2020.115832] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 12/17/2020] [Accepted: 12/18/2020] [Indexed: 12/23/2022]
Abstract
Conditional deletion of the PTH receptor (Pth1r) in mesenchymal progenitors reduces osteoblast differentiation and bone mass while enhancing adipogenesis and bone marrow adipose tissue. Mechanistically, PTH suppresses the expression of Zfp467, a pro-adipogenic zinc finger transcription factor. Consequently, Pth1r deficiency in mesenchymal progenitors leads to increased Zfp467 expression. Based on these observations, we hypothesized that genetic loss of Zfp467 would lead to a shift in marrow progenitor cell fate towards osteogenesis and increased bone mass. To test this hypothesis, we generated Zfp467-/- mice. Zfp467-/- mice (-/-) were significantly smaller than Zfp467+/+ mice (+/+). μCT showed significantly higher trabecular bone and cortical bone area in -/- vs. +/+, and histomorphometry showed higher structural and dynamic formation parameters in -/- mice vs. +/+. Femoral gene expression including Alpl, Sp7, and Acp5 were increased in -/-mice, whereas Adiponectin, Cebpa, Lepr, and Ppraγ mRNA were lower in -/- mice. Similarly, Fabp4 and Lep in the inguinal depot were also decreased in -/- mice. Moreover, marrow adipocyte numbers were reduced in -/- vs +/+ mice (p<0.007). In vitro, COBs and BMSCs-/- showed more positive ALP and Alizarin Red staining and a decrease in ORO droplets. Pth1r mRNA and protein levels were increased in COBs and BMSCs from -/- mice vs +/+ (p<0.02 for each parameter, -/- vs. +/+). -/- cells also exhibited enhanced endogenous levels of cAMP vs. control cells. Moreover, in an ovariectomy (OVX) mouse model, Zfp467-/- mice had significantly lower fat mass but similar bone mass compared to OVX +/+ mice. In contrast, in a high fat diet (HFD) mouse model, in addition to reduced adipocyte volume and adipogenesis related gene expression in both peripheral and bone marrow fat tissue, greater osteoblast number and higher osteogenesis related gene expression were also observed in -/- HFD mice vs. +/+ HFD mice. Taken together, these results demonstrate that ZFP467 negatively influences skeletal homeostasis and favors adipogenesis. Global deletion of Zfp467 increases PTHR1, cAMP and bone turnover, hence its repression is a component of PTH signaling and its regulation. These data support a critical role for Zfp467 in early lineage allocation and provide a novel potential mechanism by which PTH acts in an anabolic manner on the bone remodeling unit.
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Affiliation(s)
- Phuong T Le
- Maine Medical Center Research Institute, Maine Medical Center, Scarborough, ME 04074, USA
| | - Hanghang Liu
- Maine Medical Center Research Institute, Maine Medical Center, Scarborough, ME 04074, USA
| | - Lama Alabdulaaly
- Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Yosta Vegting
- University of Amsterdam, Amsterdam UMC, Meibergdreef 9, 1105, AZ, Amsterdam, the Netherlands
| | - Isabella L Calle
- Maine Medical Center Research Institute, Maine Medical Center, Scarborough, ME 04074, USA; Graduate Medical Sciences, Boston University School of Medicine, Boston, MA 02118, USA
| | - Francesca Gori
- Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Beate Lanske
- Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA 02115, USA
| | - Roland Baron
- Division of Bone and Mineral Research, Harvard School of Dental Medicine, Boston, MA 02115, USA; Harvard Medical School, Department of Medicine and Endocrine Unit, Massachusetts General Hospital, Boston, 02115, USA
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Maine Medical Center, Scarborough, ME 04074, USA.
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Merlotti D, Cosso R, Eller-Vainicher C, Vescini F, Chiodini I, Gennari L, Falchetti A. Energy Metabolism and Ketogenic Diets: What about the Skeletal Health? A Narrative Review and a Prospective Vision for Planning Clinical Trials on this Issue. Int J Mol Sci 2021; 22:ijms22010435. [PMID: 33406758 PMCID: PMC7796307 DOI: 10.3390/ijms22010435] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 12/27/2020] [Accepted: 12/30/2020] [Indexed: 12/15/2022] Open
Abstract
The existence of a common mesenchymal cell progenitor shared by bone, skeletal muscle, and adipocytes cell progenitors, makes the role of the skeleton in energy metabolism no longer surprising. Thus, bone fragility could also be seen as a consequence of a “poor” quality in nutrition. Ketogenic diet was originally proven to be effective in epilepsy, and long-term follow-up studies on epileptic children undergoing a ketogenic diet reported an increased incidence of bone fractures and decreased bone mineral density. However, the causes of such negative impacts on bone health have to be better defined. In these subjects, the concomitant use of antiepileptic drugs and the reduced mobilization may partly explain the negative effects on bone health, but little is known about the effects of diet itself, and/or generic alterations in vitamin D and/or impaired growth factor production. Despite these remarks, clinical studies were adequately designed to investigate bone health are scarce and bone health related aspects are not included among the various metabolic pathologies positively influenced by ketogenic diets. Here, we provide not only a narrative review on this issue, but also practical advice to design and implement clinical studies on ketogenic nutritional regimens and bone health outcomes. Perspectives on ketogenic regimens, microbiota, microRNAs, and bone health are also included.
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Affiliation(s)
- Daniela Merlotti
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy; (D.M.); (L.G.)
| | - Roberta Cosso
- Istituto Auxologico Italiano “Scientific Institute for Hospitalisation and Care”, 20100 Milano, Italy; (R.C.); (I.C.)
| | - Cristina Eller-Vainicher
- Unit of Endocrinology, Fondazione IRCCS Cà Granda-Ospedale Maggiore Policlinico Milano, 20122 Milano, Italy;
| | - Fabio Vescini
- Endocrinology and Metabolism Unit, University-Hospital S. Maria della Misericordia of Udine, 33100 Udine, Italy;
| | - Iacopo Chiodini
- Istituto Auxologico Italiano “Scientific Institute for Hospitalisation and Care”, 20100 Milano, Italy; (R.C.); (I.C.)
- Department of Medical Biotechnology and Translational Medicine, University of Milan, 20122 Milano, Italy
| | - Luigi Gennari
- Department of Medicine, Surgery and Neurosciences, University of Siena, 53100 Siena, Italy; (D.M.); (L.G.)
| | - Alberto Falchetti
- Istituto Auxologico Italiano “Scientific Institute for Hospitalisation and Care”, 20100 Milano, Italy; (R.C.); (I.C.)
- Correspondence:
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Estell EG, Rosen CJ. Emerging insights into the comparative effectiveness of anabolic therapies for osteoporosis. Nat Rev Endocrinol 2021; 17:31-46. [PMID: 33149262 DOI: 10.1038/s41574-020-00426-5] [Citation(s) in RCA: 68] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/18/2020] [Indexed: 01/01/2023]
Abstract
Over the past three decades, the mainstay of treatment for osteoporosis has been antiresorptive agents (such as bisphosphonates), which have been effective with continued administration in lowering fracture risk. However, the clinical landscape has changed as adherence to these medications has declined due to perceived adverse effects. As a result, decreases in hip fracture rates that followed the introduction of bisphosphonates have now levelled off, which is coincident with a decline in the use of the antiresorptive agents. In the past two decades, two types of anabolic agents (including three new drugs), which represent a novel approach to improving bone quality by increasing bone formation, have been approved. These therapies are expected to lead to a new clinical paradigm in which anabolic agents will be used either alone or in combination with antiresorptive agents to build new bone and reduce fracture risk. This Review examines the mechanisms of action for these anabolic agents by detailing their receptor-activating properties for key cell types in the bone and marrow niches. Using these advances in bone biology as context, the comparative effectiveness of these anabolic agents is discussed in relation to other therapeutic options for osteoporosis to better guide their clinical application in the future.
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Affiliation(s)
- Eben G Estell
- Maine Medical Center Research Institute, Scarborough, ME, USA
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56
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Sun NN, He DM, Yang C, Zhou Q. Posttraumatic Osteoarthritis of Temporomandibular Joint in Miniature Pigs. J HARD TISSUE BIOL 2021. [DOI: 10.2485/jhtb.30.79] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Ning-Ning Sun
- Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases
| | - Dong-Mei He
- Department of Oral and Maxillofacial Surgery, Shanghai Ninth People’s Hospital, School of Stomatology, Shanghai Jiao Tong University School of Medicine
| | - Chi Yang
- Department of Oral and Maxillofacial Surgery, Shanghai Ninth People’s Hospital, School of Stomatology, Shanghai Jiao Tong University School of Medicine
| | - Qing Zhou
- Department of Oral and Maxillofacial Surgery, School and Hospital of Stomatology, China Medical University, Liaoning Provincial Key Laboratory of Oral Diseases
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57
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Hollenberg AM, Smith CO, Shum LC, Awad H, Eliseev RA. Lactate Dehydrogenase Inhibition With Oxamate Exerts Bone Anabolic Effect. J Bone Miner Res 2020; 35:2432-2443. [PMID: 32729639 PMCID: PMC7736558 DOI: 10.1002/jbmr.4142] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/14/2020] [Accepted: 07/18/2020] [Indexed: 12/15/2022]
Abstract
Cellular bioenergetics is a promising new therapeutic target in aging, cancer, and diabetes because these pathologies are characterized by a shift from oxidative to glycolytic metabolism. We have previously reported such glycolytic shift in aged bone as a major contributor to bone loss in mice. We and others also showed the importance of oxidative phosphorylation (OxPhos) for osteoblast differentiation. It is therefore reasonable to propose that stimulation of OxPhos will have bone anabolic effect. One strategy widely used in cancer research to stimulate OxPhos is inhibition of glycolysis. In this work, we aimed to evaluate the safety and efficacy of pharmacological inhibition of glycolysis to stimulate OxPhos and promote osteoblast bone-forming function and bone anabolism. We tested a range of glycolytic inhibitors including 2-deoxyglucose, dichloroacetate, 3-bromopyruvate, and oxamate. Of all the studied inhibitors, only a lactate dehydrogenase (LDH) inhibitor, oxamate, did not show any toxicity in either undifferentiated osteoprogenitors or osteoinduced cells in vitro. Oxamate stimulated both OxPhos and osteoblast differentiation in osteoprogenitors. In vivo, oxamate improved bone mineral density, cortical bone architecture, and bone biomechanical strength in both young and aged C57BL/6J male mice. Oxamate also increased bone formation by osteoblasts without affecting bone resorption. In sum, our work provided a proof of concept for the use of anti-glycolytic strategies in bone and identified a small molecule LDH inhibitor, oxamate, as a safe and efficient bone anabolic agent. © 2020 American Society for Bone and Mineral Research (ASBMR).
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Affiliation(s)
- Alex M. Hollenberg
- Center for Musculoskeletal Research, University of Rochester School of Medicine & Dentistry, Rochester, NY
| | - Charles O. Smith
- Center for Musculoskeletal Research, University of Rochester School of Medicine & Dentistry, Rochester, NY
| | - Laura C. Shum
- Center for Musculoskeletal Research, University of Rochester School of Medicine & Dentistry, Rochester, NY
| | - Hani Awad
- Center for Musculoskeletal Research, University of Rochester School of Medicine & Dentistry, Rochester, NY
| | - Roman A. Eliseev
- Center for Musculoskeletal Research, University of Rochester School of Medicine & Dentistry, Rochester, NY
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58
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Lee WC, Ji X, Nissim I, Long F. Malic Enzyme Couples Mitochondria with Aerobic Glycolysis in Osteoblasts. Cell Rep 2020; 32:108108. [PMID: 32905773 PMCID: PMC8183612 DOI: 10.1016/j.celrep.2020.108108] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/24/2020] [Accepted: 08/13/2020] [Indexed: 01/12/2023] Open
Abstract
The metabolic program of osteoblasts, the chief bone-making cells, remains incompletely understood. Here in murine calvarial cells, we establish that osteoblast differentiation under aerobic conditions is coupled with a marked increase in glucose consumption and lactate production but reduced oxygen consumption. As a result, aerobic glycolysis accounts for approximately 80% of the ATP production in mature osteoblasts. In vivo tracing with 13C-labeled glucose in the mouse shows that glucose in bone is readily metabolized to lactate but not organic acids in the TCA cycle. Glucose tracing in osteoblast cultures reveals that pyruvate is carboxylated to form malate integral to the malate-aspartate shuttle. RNA sequencing (RNA-seq) identifies Me2, encoding the mitochondrial NAD-dependent isoform of malic enzyme, as being specifically upregulated during osteoblast differentiation. Knockdown of Me2 markedly reduces the glycolytic flux and impairs osteoblast proliferation and differentiation. Thus, the mitochondrial malic enzyme functionally couples the mitochondria with aerobic glycolysis in osteoblasts.
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Affiliation(s)
- Wen-Chih Lee
- Translational Research Program in Pediatric Orthopedics, The Children's Hospital of Philadelphia, PA 19104, USA
| | - Xing Ji
- Translational Research Program in Pediatric Orthopedics, The Children's Hospital of Philadelphia, PA 19104, USA
| | - Itzhak Nissim
- Division of Genetics and Metabolism, The Children's Hospital of Philadelphia, Philadelphia, PA 19104, USA; Department of Pediatrics, Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Fanxin Long
- Translational Research Program in Pediatric Orthopedics, The Children's Hospital of Philadelphia, PA 19104, USA; Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Yang J, Ueharu H, Mishina Y. Energy metabolism: A newly emerging target of BMP signaling in bone homeostasis. Bone 2020; 138:115467. [PMID: 32512164 PMCID: PMC7423769 DOI: 10.1016/j.bone.2020.115467] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 05/29/2020] [Accepted: 06/01/2020] [Indexed: 12/11/2022]
Abstract
Energy metabolism is the process of generating energy (i.e. ATP) from nutrients. This process is indispensable for cell homeostasis maintenance and responses to varying conditions. Cells require energy for growth and maintenance and have evolved to have multiple pathways to produce energy. Both genetic and functional studies have demonstrated that energy metabolism, such as glucose, fatty acid, and amino acid metabolism, plays important roles in the formation and function of bone cells including osteoblasts, osteocytes, and osteoclasts. Dysregulation of energy metabolism in bone cells consequently disturbs the balance between bone formation and bone resorption. Metabolic diseases have also been reported to affect bone homeostasis. Bone morphogenic protein (BMP) signaling plays critical roles in regulating the formation and function of bone cells, thus affecting bone development and homeostasis. Mutations of BMP signaling-related genes in mice have been reported to show abnormalities in energy metabolism in many tissues, including bone. In addition, BMP signaling correlates with critical signaling pathways such as mTOR, HIF, Wnt, and self-degradative process autophagy to coordinate energy metabolism and bone homeostasis. These findings will provide a newly emerging target of BMP signaling and potential therapeutic strategies and the improved management of bone diseases. This review summarizes the recent advances in our understanding of (1) energy metabolism in regulating the formation and function of bone cells, (2) function of BMP signaling in whole body energy metabolism, and (3) mechanistic interaction of BMP signaling with other signaling pathways and biological processes critical for energy metabolism and bone homeostasis.
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Affiliation(s)
- Jingwen Yang
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA; The State Key Laboratory Breeding Base of Basic Science of Stomatology & Key Laboratory for Oral Biomedicine of Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, Hubei 430079, China.
| | - Hiroki Ueharu
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yuji Mishina
- Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, Ann Arbor, MI 48109, USA.
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60
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Hannah SS, McFadden S, McNeilly A, McClean C. "Take My Bone Away?" Hypoxia and bone: A narrative review. J Cell Physiol 2020; 236:721-740. [PMID: 32643217 DOI: 10.1002/jcp.29921] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 06/18/2020] [Accepted: 06/19/2020] [Indexed: 12/11/2022]
Abstract
To maintain normal cellular and physiological function, sufficient oxygen is required. Recently, evidence has suggested that hypoxia, either pathological or environmental, may influence bone health. It appears that bone cells are distinctly responsive to hypoxic stimuli; for better or worse, this is still yet to be elucidated. Hypoxia has been shown to offer potentially therapeutic effects for bone by inducing an osteogenic-angiogenic response, although, others have noted excessive osteoclastic bone resorption instead. Much evidence suggests that the hypoxic-inducible pathway is integral in mediating the changes in bone metabolism. Furthermore, many factors associated with hypoxia including changes in energy metabolism, acid-base balance and the increased generation of reactive oxygen species, are known to influence bone metabolism. This review aims to examine some of the putative mechanisms responsible for hypoxic-induced alterations of bone metabolism, with regard to osteoclasts and osteoblasts, both positive and negative.
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Affiliation(s)
- Scott S Hannah
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
| | - Sonyia McFadden
- Institute of Nursing and Health Research, Ulster University, Newtownabbey, Antrim, UK
| | - Andrea McNeilly
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
| | - Conor McClean
- Sport and Exercise Sciences Research Institute, Ulster University, Newtownabbey, Antrim, UK
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Abstract
The skeleton is highly vascularized due to the various roles blood vessels play in the homeostasis of bone and marrow. For example, blood vessels provide nutrients, remove metabolic by-products, deliver systemic hormones, and circulate precursor cells to bone and marrow. In addition to these roles, bone blood vessels participate in a variety of other functions. This article provides an overview of the afferent, exchange and efferent vessels in bone and marrow and presents the morphological layout of these blood vessels regarding blood flow dynamics. In addition, this article discusses how bone blood vessels participate in bone development, maintenance, and repair. Further, mechanical loading-induced bone adaptation is presented regarding interstitial fluid flow and pressure, as regulated by the vascular system. The role of the sympathetic nervous system is discussed in relation to blood vessels and bone. Finally, vascular participation in bone accrual with intermittent parathyroid hormone administration, a medication prescribed to combat age-related bone loss, is described and age- and disease-related impairments in blood vessels are discussed in relation to bone and marrow dysfunction. © 2020 American Physiological Society. Compr Physiol 10:1009-1046, 2020.
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Affiliation(s)
- Rhonda D Prisby
- Bone Vascular and Microcirculation Laboratory, Department of Kinesiology, University of Texas at Arlington, Arlington, Texas, USA
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62
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Kawaguchi M, Kawao N, Takafuji Y, Ishida M, Kaji H. Myonectin inhibits the differentiation of osteoblasts and osteoclasts in mouse cells. Heliyon 2020; 6:e03967. [PMID: 32514479 PMCID: PMC7266783 DOI: 10.1016/j.heliyon.2020.e03967] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 05/01/2020] [Accepted: 05/07/2020] [Indexed: 11/03/2022] Open
Abstract
Myonectin is a myokine, which is involved in the pathophysiology of diabetes and obesity, and various myokines are involved in the interactions between skeletal muscle and bone. However, roles of myonectin in bone have still remained unknown. We therefore examined the effects of myonectin on mouse osteoblast and osteoclast differentiation in vitro. Myonectin significantly suppressed the mRNA levels of osteogenic genes and alkaline phosphatase (ALP) activity in mouse osteoblasts. As for osteoclasts, myonectin significantly suppressed osteoclast formation as well as the mRNA levels of osteoclast-related genes enhanced by receptor activator nuclear factor κB ligand (RANKL) from mouse monocytic RAW264.7 cells. Moreover, myonectin significantly suppressed osteoclast formation from mouse bone marrow cells in the presence of macrophage-colony stimulating factor and RANKL. On the other hand, myonectin significantly suppressed RANKL-induced oxygen consumption rate and peroxisome proliferator-activated receptor γ coactivator-1β mRNA levels in RAW264.7 cells, although myonectin did not affect these mitochondrial biogenesis parameters in mouse osteoblasts. In conclusion, the present study demonstrated that myonectin suppresses the differentiation and ALP activity in mouse osteoblasts. Moreover, myonectin suppressed osteoclast differentiation from mouse bone marrow and RAW264.7 cells partly through an inhibition of mitochondrial biogenesis.
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Affiliation(s)
- Miku Kawaguchi
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Naoyuki Kawao
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Yoshimasa Takafuji
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Masayoshi Ishida
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
| | - Hiroshi Kaji
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka, 589-8511, Japan
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Pal S, Porwal K, Rajak S, Sinha RA, Chattopadhyay N. Selective dietary polyphenols induce differentiation of human osteoblasts by adiponectin receptor 1-mediated reprogramming of mitochondrial energy metabolism. Biomed Pharmacother 2020; 127:110207. [PMID: 32422565 DOI: 10.1016/j.biopha.2020.110207] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/18/2020] [Accepted: 04/28/2020] [Indexed: 12/30/2022] Open
Abstract
Anabolic therapies for osteoporosis including dietary polyphenols promote osteoblast function by influencing its energy metabolism. Among the dietary polyphenols, the beneficial skeletal effects of genistein (an isoflavone), kaempferol (a flavone), resveratrol (RES, a stilbenoid) and epigallocatechin gallate (EGCG, a catechin) have been reported in preclinical studies. We studied the action mechanism of these nutraceuticals on osteoblast bioenergetics. All stimulated differentiation of human fetal osteoblasts (hFOB). However, only EGCG and RES stimulated mitochondrial parameters including basal and maximum respiration, spare respiratory capacity and ATP production (a measure of the activity of electron transport chain/ETC). Increases in these parameters were due to increased mitochondrial biogenesis and consequent upregulation of several mitochondrial proteins including those involved in ETC. Rotenone blocked the osteogenic effect of EGCG and RES suggesting the mediatory action of mitochondria. Both compounds rapidly activated AMPK, and dorsomorphin (an AMPK inhibitor) abolished ATP production stimulated by these compounds. Moreover, EGCG and RES upregulated the mitochondrial biogenesis factor, PGC-1α which is downstream of AMPK activation, and silencing PGC-1α blocked their stimulatory effects on ATP production and hFOB differentiation. Adiponectin receptor 1 (AdipoR1) is an upstream regulator of PGC-1α, and both compounds increased the expression of AdipoR1 but not AdipoR2. Silencing AdipoR1 blocked the upregulation of EGCG/RES-induced PGC-1α and hFOB differentiation. In rat calvarium, both compounds increased AdipoR1, PGC-1α, and RunX2 (the osteoblast transcription factor) with a concomitant increase in mitochondrial copy number and ATP levels. We conclude that EGCG and RES display osteogenic effects by reprogramming osteoblastic bioenergetics by acting as the AdipoR1 agonists.
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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
| | - Sangam Rajak
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India
| | - Rohit A Sinha
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, 226014, India
| | - Naibedya Chattopadhyay
- Division of Endocrinology, CSIR-Central Drug Research Institute, Council of Scientific and Industrial Research, Lucknow, 226031, India.
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Ouyang N, Li H, Wang M, Shen H, Si J, Shen G. The Transcription Factor Foxc1 Promotes Osteogenesis by Directly Regulating Runx2 in Response of Intermittent Parathyroid Hormone (1-34) Treatment. Front Pharmacol 2020; 11:592. [PMID: 32431614 PMCID: PMC7216818 DOI: 10.3389/fphar.2020.00592] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2020] [Accepted: 04/17/2020] [Indexed: 01/23/2023] Open
Abstract
Parathyroid hormone (PTH) is crucial for bone remodeling. Intermittent PTH (1–34) administration stimulates osteogenesis and promotes bone formation; however, the possible targets and underlying mechanisms still remain unclear. In this study, functional links between PTH and Foxc1, a transcription factor reported to be predominant in skeletal development and formation, were indicated. We determined the impacts of Foxc1 on in vitro osteogenic differentiation and in vivo bone regeneration under intermittent PTH induction, and further explored its possible targets. We found that the expression level of Foxc1 was upregulated during osteogenic induction by intermittent PTH treatment, and the elevated expression of Foxc1 induced by PTH was inhibited by PTH1R silencing, while rescued by intermittent PTH supplement. By gain- and loss-of-function strategies targeting Foxc1 in MC3T3-E1 cells, we demonstrated that Foxc1 could promote in vitro osteogenic differentiation by intermittent PTH induction. Moreover, immunofluorescence analysis indicated the nuclear co-localization of Foxc1 with Runx2. Luciferase-reporter and chromatin immunoprecipitation analysis further confirmed that Foxc1 could bind to the P1 promoter region of Runx2 directly, which plays an indispensable part in osteogenic differentiation and bone mineralization. Meanwhile, we also revealed that Foxc1 could promote bone regeneration induced by intermittent PTH treatment in vivo. Taken together, this study revealed the role and mechanism of Foxc1 on in vitro osteogenic differentiation and in vivo bone regeneration in response of intermittent PTH treatment.
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Affiliation(s)
- Ningjuan Ouyang
- Department of Orthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Hongliang Li
- Department of Oral and Cranio-maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Minjiao Wang
- Department of Oral and Cranio-maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Hongzhou Shen
- Department of Oral and Cranio-maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Jiawen Si
- Department of Oral and Cranio-maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
| | - Guofang Shen
- Department of Oral and Cranio-maxillofacial Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai Key Laboratory of Stomatology, Shanghai, China
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65
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Takafuji Y, Tatsumi K, Ishida M, Kawao N, Okada K, Kaji H. Extracellular vesicles secreted from mouse muscle cells suppress osteoclast formation: Roles of mitochondrial energy metabolism. Bone 2020; 134:115298. [PMID: 32092478 DOI: 10.1016/j.bone.2020.115298] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Revised: 02/20/2020] [Accepted: 02/20/2020] [Indexed: 12/13/2022]
Abstract
Recent reports have described the interactions of muscle and bone. Various muscle-derived humoral factors, known as myokines, affect bone. Although extracellular vesicles (EVs) play a vital role in physiological and pathophysiological processes by transferring their contents to distant tissues during bone metabolism, the roles of EVs in the muscle-bone interactions remain unknown. In the present study, we investigated the effects of EVs secreted from mouse muscle C2C12 cells on mouse bone cells and mitochondrial biogenesis. EVs secreted from C2C12 cells (Myo-EVs) were isolated from the conditioned medium of C2C12 cells by ultracentrifugation. Myo-EVs suppressed osteoclast formation as well as the expression of tartrate-resistant acid phosphatase, cathepsin K, nuclear factor of activated T-cells cytoplasmic 1 and dendritic cell-specific transmembrane protein induced by receptor activator of nuclear factor κB ligand (RANKL) in mouse bone marrow cells and preosteoclastic Raw264.7 cells. Moreover, Myo-EVs suppressed oxygen consumption and mRNA expression of the mitochondrial biogenesis markers enhanced by RANKL in these cells. However, Myo-EVs did not affect the phenotypes or mitochondrial biogenesis of mouse primary osteoblasts. In conclusion, the present study showed for the first time that Myo-EVs suppress osteoclast formation and mitochondrial energy metabolism in mouse bone marrow and Raw264.7 cells. EVs secreted from skeletal muscles might be a crucial mediator of muscle-bone interactions.
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Affiliation(s)
- Yoshimasa Takafuji
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan
| | - Kohei Tatsumi
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan
| | - Masayoshi Ishida
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan
| | - Naoyuki Kawao
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan
| | - Kiyotaka Okada
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan
| | - Hiroshi Kaji
- Department of Physiology and Regenerative Medicine, Kindai University Faculty of Medicine, 377-2 Ohnohigashi, Osakasayama, Osaka 589-8511, Japan.
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Ohbayashi Y, Iwasaki A, Nakai F, Mashiba T, Miyake M. A comparative effectiveness pilot study of teriparatide for medication-related osteonecrosis of the jaw: daily versus weekly administration. Osteoporos Int 2020; 31:577-585. [PMID: 31768589 DOI: 10.1007/s00198-019-05199-w] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Accepted: 10/16/2019] [Indexed: 01/08/2023]
Abstract
UNLABELLED We studied the effectiveness of teriparatide (TPTD) for treating medication-related osteonecrosis of the jaw (MRONJ) in patients with osteoporosis and examined differences in the clinical outcomes following daily versus weekly TPTD. The outcomes were significantly improved in the entire patient series and the daily group. PURPOSE Teriparatide (TPTD) treatment for Stage II-III medication-related osteonecrosis of the jaw (MRONJ) in osteoporotic patients has yielded promising results in uncontrolled studies. The daily administration and the weekly administration of TPTD have been reported to improve outcomes in MRONJ. Herein, we sought to identify differences in the clinical outcomes of MRONJ patients treated with daily TPTD versus weekly TPTD. METHODS We enrolled 13 patients and randomly assigned them to receive either of two treatments: 1×/week 56.5-μg TPTD injection for 6 months (weekly group; n = 6 patients after 1 dropout), or 20-μg TPTD injection daily for 6 months (daily group; n = 6 patients). Patients in both groups received conventional therapy plus intensive antibiotic therapy as necessary. We compared the changes in the patients' clinical stage of MRONJ, bone metabolism, percentage of bone formation, and bone turnover markers between the weekly and daily groups. RESULTS TPTD treatment with MRONJ led to partial remission or complete remission in 5 daily-group patients and 3 weekly-group patients. The MRONJ stage was significantly improved from baseline to 6 months of treatment in the entire series of 12 patients (p = 0.008); the weekly group did not show significant improvement, but the daily group did (p = 0.01). CONCLUSIONS This study provides the first comparison of clinical outcomes between MRONJ patients who received daily or weekly TPTD injections. Six months of treatment with TPTD realized a significant improvement of MRONJ stage in both the entire patient series and the daily group.
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Affiliation(s)
- Y Ohbayashi
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Kita-gun, Kagawa, Miki-cho, 761-0793, Japan.
| | - A Iwasaki
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Kita-gun, Kagawa, Miki-cho, 761-0793, Japan
| | - F Nakai
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Kita-gun, Kagawa, Miki-cho, 761-0793, Japan
| | - T Mashiba
- Department of Orthopedic Surgery, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Kita-gun, Kagawa, Miki-cho, 761-0793, Japan
| | - M Miyake
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, Kagawa University, 1750-1 Ikenobe, Kita-gun, Kagawa, Miki-cho, 761-0793, Japan
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Metabolic programming determines the lineage-differentiation fate of murine bone marrow stromal progenitor cells. Bone Res 2019; 7:35. [PMID: 31754546 PMCID: PMC6856123 DOI: 10.1038/s41413-019-0076-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 07/22/2019] [Accepted: 08/18/2019] [Indexed: 12/30/2022] Open
Abstract
Enhanced bone marrow adipogenesis and impaired osteoblastogenesis have been observed in obesity, suggesting that the metabolic microenvironment regulates bone marrow adipocyte and osteoblast progenitor differentiation fate. To determine the molecular mechanisms, we studied two immortalized murine cell lines of adipocyte or osteoblast progenitors (BMSCsadipo and BMSCsosteo, respectively) under basal and adipogenic culture conditions. At baseline, BMSCsadipo, and BMSCsosteo exhibit a distinct metabolic program evidenced by the presence of specific global gene expression, cellular bioenergetics, and metabolomic signatures that are dependent on insulin signaling and glycolysis in BMSCsosteo versus oxidative phosphorylation in BMSCsadipo. To test the flexibility of the metabolic program, we treated BMSCsadipo with parathyroid hormone, S961 (an inhibitor of insulin signaling) and oligomycin (an inhibitor of oxidative phosphorylation). The treatment induced significant changes in cellular bioenergetics that were associated with decreased adipocytic differentiation. Similarly, 12 weeks of a high-fat diet in mice led to the expansion of adipocyte progenitors, enhanced adipocyte differentiation and insulin signaling in cultured BMSCs. Our data demonstrate that BMSC progenitors possess a distinct metabolic program and are poised to respond to exogenous metabolic cues that regulate their differentiation fate.
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Sutkeviciute I, Clark LJ, White AD, Gardella TJ, Vilardaga JP. PTH/PTHrP Receptor Signaling, Allostery, and Structures. Trends Endocrinol Metab 2019; 30:860-874. [PMID: 31699241 PMCID: PMC6857722 DOI: 10.1016/j.tem.2019.07.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/09/2019] [Accepted: 07/12/2019] [Indexed: 02/08/2023]
Abstract
The parathyroid hormone (PTH) type 1 receptor (PTHR) is the canonical G protein-coupled receptor (GPCR) for PTH and PTH-related protein (PTHrP) and the key regulator of calcium homeostasis and bone turnover. PTHR function is critical for human health to maintain homeostatic control of ionized serum Ca2+ levels and has several unusual signaling features, such as endosomal cAMP signaling, that are well-studied but not structurally understood. In this review, we discuss how recently solved high resolution near-atomic structures of hormone-bound PTHR in its inactive and active signaling states and discovery of extracellular Ca2+ allosterism shed light on the structural basis for PTHR signaling and function.
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Affiliation(s)
- Ieva Sutkeviciute
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Lisa J Clark
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Graduate Program in Molecular Biophysics and Structural Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Alex D White
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA; Graduate Program in Molecular Pharmacology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Thomas J Gardella
- Endocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jean-Pierre Vilardaga
- Laboratory for GPCR Biology, Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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69
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Abstract
Osteoblasts are specialized mesenchymal cells that synthesize bone matrix and coordinate the mineralization of the skeleton. These cells work in harmony with osteoclasts, which resorb bone, in a continuous cycle that occurs throughout life. The unique function of osteoblasts requires substantial amounts of energy production, particularly during states of new bone formation and remodelling. Over the last 15 years, studies have shown that osteoblasts secrete endocrine factors that integrate the metabolic requirements of bone formation with global energy balance through the regulation of insulin production, feeding behaviour and adipose tissue metabolism. In this article, we summarize the current understanding of three osteoblast-derived metabolic hormones (osteocalcin, lipocalin and sclerostin) and the clinical evidence that suggests the relevance of these pathways in humans, while also discussing the necessity of specific energy substrates (glucose, fatty acids and amino acids) to fuel bone formation and promote osteoblast differentiation.
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Affiliation(s)
- Naomi Dirckx
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Megan C Moorer
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - Thomas L Clemens
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- The Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- The Baltimore Veterans Administration Medical Center, Baltimore, MD, USA.
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Ho PWM, Chan AS, Pavlos NJ, Sims NA, Martin TJ. Brief exposure to full length parathyroid hormone-related protein (PTHrP) causes persistent generation of cyclic AMP through an endocytosis-dependent mechanism. Biochem Pharmacol 2019; 169:113627. [PMID: 31476292 DOI: 10.1016/j.bcp.2019.113627] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 08/28/2019] [Indexed: 12/17/2022]
Abstract
Parathyroid hormone (PTH)-related protein (PTHrP) (gene name Pthlh) was discovered as the factor responsible for the humoral hypercalcemia of malignancy. It shares such sequence similarity with PTH in the amino-terminal region that the two are equally able to act through a single G protein-coupled receptor, PTH1R. A number of biological activities are ascribed to domains of PTHrP beyond the amino-terminal domain. PTH functions as a circulating hormone, but PTHrP is generated locally in many tissues including bone, where it acts as a paracrine factor on osteoblasts and osteocytes. The present study compares how PTH and PTHrP influence cyclic AMP (cAMP) formation through adenylyl cyclase, the first event in cell activation through PTH1R. Brief exposure to full length PTHrP(1-141) in several osteoblastic cell culture systems was followed by sustained adenylyl cyclase activity for more than an hour after ligand washout. This effect was dose-dependent and was not found with shorter PTHrP or PTH peptides even though they were fully able to activate adenylyl cyclase with acute treatment. The persistent activation response to PTHrP(1-141) was seen also with later events in the cAMP/PKA pathway, including persistent activation of CRE-luciferase and sustained regulation of several CREB-responsive mRNAs, up to 24 h after the initial exposure. Pharmacologic blockade of endocytosis prevented the persistent activation of cAMP and gene responses. We conclude that full length PTHrP, the likely local physiological effector in bone, differs in intracellular action to PTH by undergoing endosomal translocation to induce a prolonged adenylyl cyclase activation in its target cells.
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Affiliation(s)
- Patricia W M Ho
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia
| | - Audrey S Chan
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia; School of Biomedical Sciences, The University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Nathan J Pavlos
- School of Biomedical Sciences, The University of Western Australia, Nedlands, Western Australia 6009, Australia
| | - Natalie A Sims
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia; Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Melbourne, Victoria 3065, Australia
| | - T John Martin
- Bone Biology and Disease Unit, St. Vincent's Institute of Medical Research, Melbourne, Victoria 3065, Australia; Department of Medicine, The University of Melbourne, St. Vincent's Hospital, Melbourne, Victoria 3065, Australia.
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71
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Ge X, Li Z, Jing S, Wang Y, Li N, Lu J, Yu J. Parathyroid hormone enhances the osteo/odontogenic differentiation of dental pulp stem cells via ERK and P38 MAPK pathways. J Cell Physiol 2019; 235:1209-1221. [PMID: 31276209 DOI: 10.1002/jcp.29034] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 06/12/2019] [Indexed: 12/25/2022]
Abstract
OBJECTIVE Parathyroid hormone (PTH) is a main systemic mediator of calcium and phosphate homeostasis in the bone. Dental pulp stem cells (DPSCs) have been extensively studied in the regeneration of bone and tooth tissues. This paper aims to uncover the influences of PTH on the proliferative ability and osteo/odontogenic differentiation of DPSCs, as well as the underlying mechanisms. MATERIALS AND METHODS The optimal concentration of PTH on DPSCs was determined by alkaline phosphatase (ALP) activity assay, ALP staining and western blot analysis. Proliferative ability and cell cycle distribution of DPSCs were analyzed by Cell counting kit-8, 5-ethynyl-20-deoxyuridine assay, and flow cytometry. Osteo/odontogenic capacity of DPSCs was evaluated and finally, the involvement of mitogen-activated protein kinase (MAPK) pathway was assessed. RESULTS Purified DPSCs were obtained by enzymatic digestion, which presented a typical fibroblast-like morphology. 10-9 mol/L PTH was concerned as the optimal concentration for DPSCs induction. 10-9 mol/L PTH treatment did not change the proliferative rate of DPSCs (p > .05). Relative expressions of DSPP/DSPP, RUNX2/RUNX2, OSX/OSX, and ALP/ALP were upregulated in PTH-treated DPSCs relative to control group. Particularly, their mRNA/protein levels at Day 7 were markedly higher relative to those at Day 3 (p < .05 or p < .01). Mineralized nodules were formed after PTH induction, and calcium content increased by cetylpyridinium chloride quantitative analysis. Mechanistically, the protein levels of p-ERK and p-P38 significantly increased after PTH treatment, and the inhibitors targeting MAPK were identified that weakened the effects of PTH on the committed differentiation of DPSCs. CONCLUSIONS PTH enhances the osteo/odontogenic differentiation capacity of DPSCs via ERK and P38 signaling pathways.
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Affiliation(s)
- Xingyun Ge
- Key Laboratory of Oral Diseases of Jiangsu Province and Stomatological Institute of Nanjing Medical University, Nanjing, Jiangsu, China.,Endodontic Department, School of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zehan Li
- Key Laboratory of Oral Diseases of Jiangsu Province and Stomatological Institute of Nanjing Medical University, Nanjing, Jiangsu, China.,Endodontic Department, School of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Shuanglin Jing
- Endodontic Department, School of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Yanqiu Wang
- Endodontic Department, School of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Na Li
- Key Laboratory of Oral Diseases of Jiangsu Province and Stomatological Institute of Nanjing Medical University, Nanjing, Jiangsu, China.,Endodontic Department, School of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiamin Lu
- Key Laboratory of Oral Diseases of Jiangsu Province and Stomatological Institute of Nanjing Medical University, Nanjing, Jiangsu, China.,Endodontic Department, School of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jinhua Yu
- Endodontic Department, School of Stomatology, Nanjing Medical University, Nanjing, Jiangsu, China
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Variable osteogenic performance of MC3T3-E1 subclones impacts their utility as models of osteoblast biology. Sci Rep 2019; 9:8299. [PMID: 31165768 PMCID: PMC6549152 DOI: 10.1038/s41598-019-44575-8] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 05/13/2019] [Indexed: 12/12/2022] Open
Abstract
The spontaneously immortalized murine calvarial cell line MC3T3-E1 and its derivative subclones are widely used models of osteoblast biology. Many investigators have reported conflicting data under seemingly similar experimental conditions, though the specific subclone studied is often not specified. The purpose of this study was to directly compare the commercially available MC3T3-E1 subclones 4, 14, and 24 in terms of responsiveness to osteogenic induction media and/or stimulation with rhPTH[1–34]. We assayed osteogenic gene expression, capacity to deposit and mineralize a collagenous matrix, and the expression and signaling function of PTH1R. Our data demonstrate that each subclone bears little functional resemblance to the others, or to primary calvarial osteoblasts. Specifically, whereas subclone 4 is responsive to PTH stimulation and capable of matrix mineralization, subclones 14 and 24 do not faithfully replicate these key aspects of osteoblast biology. Furthermore, little overlap was observed between the gene expression profile of subclone 4 and primary calvarial osteoblasts. Our experience working with these cell lines demonstrates that the MC3T3-E1 derived cell lines are imperfect models of osteoblast biology, and reinforce the importance of clearly articulating selection and reporting of research materials.
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Sun N, Uda Y, Azab E, Kochen A, Santos RNCE, Shi C, Kobayashi T, Wein MN, Divieti Pajevic P. Effects of histone deacetylase inhibitor Scriptaid and parathyroid hormone on osteocyte functions and metabolism. J Biol Chem 2019; 294:9722-9733. [PMID: 31068415 DOI: 10.1074/jbc.ra118.007312] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Revised: 05/02/2019] [Indexed: 01/02/2023] Open
Abstract
Bone is a highly metabolic organ that undergoes continuous remodeling to maintain its structural integrity. During development, bones, in particular osteoblasts, rely on glucose uptake. However, the role of glucose metabolism in osteocytes is unknown. Osteocytes are terminally differentiated osteoblasts orchestrating bone modeling and remodeling. In these cells, parathyroid hormone (PTH) suppresses Sost/sclerostin expression (a potent inhibitor of bone formation) by promoting nuclear translocation of class IIa histone deacetylase (HDAC) 4 and 5 and the repression of myocyte enhancer factor 2 (MEF2) type C. Recently, Scriptaid, an HDAC complex co-repressor inhibitor, has been shown to induce MEF2 activation and exercise-like adaptation in mice. In muscles, Scriptaid disrupts the HDAC4/5 co-repressor complex, increases MEF2C function, and promotes cell respiration. We hypothesized that Scriptaid, by affecting HDAC4/5 localization and MEF2C activation, might affect osteocyte functions. Treatment of the osteocytic Ocy454-12H cells with Scriptaid increased metabolic gene expression, cell respiration, and glucose uptake. Similar effects were also seen upon treatment with PTH, suggesting that both Scriptaid and PTH can promote osteocyte metabolism. Similar to PTH, Scriptaid potently suppressed Sost expression. Silencing of HDAC5 in Ocy454-12H cells abolished Sost suppression but not glucose transporter type 4 (Glut4) up-regulation induced by Scriptaid. These results demonstrate that Scriptaid increases osteocyte respiration and glucose uptake by mechanisms independent of HDAC complex inhibition. In osteocytes, Scriptaid, similar to PTH, increases binding of HDAC5 to Mef2c with suppression of Sost but only partially increases receptor activator of NF-κB ligand (Rankl) expression, suggesting a potential bone anabolic effect.
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Affiliation(s)
- Ningyuan Sun
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - Yuhei Uda
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - Ehab Azab
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - Alejandro Kochen
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - Roberto Nunes Campos E Santos
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - Chao Shi
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118.,the Department of Orthopedics, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, Shandong 250014, China, and
| | - Tokio Kobayashi
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118
| | - Marc N Wein
- the Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114
| | - Paola Divieti Pajevic
- From the Department of Molecular and Cell Biology, Henry M. Goldman School of Dental Medicine, Boston University, Boston, Massachusetts 02118,
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Shao Y, Wichern E, Childress PJ, Adaway M, Misra J, Klunk A, Burr DB, Wek RC, Mosley AL, Liu Y, Robling AG, Brustovetsky N, Hamilton J, Jacobs K, Vashishth D, Stayrook KR, Allen MR, Wallace JM, Bidwell JP. Loss of Nmp4 optimizes osteogenic metabolism and secretion to enhance bone quality. Am J Physiol Endocrinol Metab 2019; 316:E749-E772. [PMID: 30645175 PMCID: PMC6580174 DOI: 10.1152/ajpendo.00343.2018] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Revised: 01/07/2019] [Accepted: 01/09/2019] [Indexed: 12/11/2022]
Abstract
A goal of osteoporosis therapy is to restore lost bone with structurally sound tissue. Mice lacking the transcription factor nuclear matrix protein 4 (Nmp4, Zfp384, Ciz, ZNF384) respond to several classes of osteoporosis drugs with enhanced bone formation compared with wild-type (WT) animals. Nmp4-/- mesenchymal stem/progenitor cells (MSPCs) exhibit an accelerated and enhanced mineralization during osteoblast differentiation. To address the mechanisms underlying this hyperanabolic phenotype, we carried out RNA-sequencing and molecular and cellular analyses of WT and Nmp4-/- MSPCs during osteogenesis to define pathways and mechanisms associated with elevated matrix production. We determined that Nmp4 has a broad impact on the transcriptome during osteogenic differentiation, contributing to the expression of over 5,000 genes. Phenotypic anchoring of transcriptional data was performed for the hypothesis-testing arm through analysis of cell metabolism, protein synthesis and secretion, and bone material properties. Mechanistic studies confirmed that Nmp4-/- MSPCs exhibited an enhanced capacity for glycolytic conversion: a key step in bone anabolism. Nmp4-/- cells showed elevated collagen translation and secretion. The expression of matrix genes that contribute to bone material-level mechanical properties was elevated in Nmp4-/- cells, an observation that was supported by biomechanical testing of bone samples from Nmp4-/- and WT mice. We conclude that loss of Nmp4 increases the magnitude of glycolysis upon the metabolic switch, which fuels the conversion of the osteoblast into a super-secretor of matrix resulting in more bone with improvements in intrinsic quality.
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Affiliation(s)
- Yu Shao
- Department of Medical and Molecular Genetics, Indiana University School of Medicine , Indianapolis, Indiana
| | - Emily Wichern
- Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
| | - Paul J Childress
- Department of Orthopaedic Surgery, Indiana University School of Medicine , Indianapolis, Indiana
- Indiana Center for Musculoskeletal Health Indiana University School of Medicine , Indianapolis, Indiana
| | - Michele Adaway
- Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
| | - Jagannath Misra
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana
| | - Angela Klunk
- Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
| | - David B Burr
- Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
- Indiana Center for Musculoskeletal Health Indiana University School of Medicine , Indianapolis, Indiana
- Department of Biomedical Engineering, Indiana University-Purdue University , Indianapolis, Indiana
| | - Ronald C Wek
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana
| | - Amber L Mosley
- Department of Biochemistry and Molecular Biology, Indiana University School of Medicine , Indianapolis, Indiana
| | - Yunlong Liu
- Department of Medical and Molecular Genetics, Indiana University School of Medicine , Indianapolis, Indiana
| | - Alexander G Robling
- Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
- Indiana Center for Musculoskeletal Health Indiana University School of Medicine , Indianapolis, Indiana
| | - Nickolay Brustovetsky
- Department of Pharmacology and Toxicology, Indiana University School of Medicine , Indianapolis, Indiana
| | - James Hamilton
- Department of Pharmacology and Toxicology, Indiana University School of Medicine , Indianapolis, Indiana
| | - Kylie Jacobs
- Department of Microbiology and Immunology, Indiana University School of Medicine , Indianapolis, Indiana
| | - Deepak Vashishth
- Center for Biotechnology and Interdisciplinary Studies and Department of Biomedical Engineering, Rensselaer Polytechnic Institute , Troy, New York
| | - Keith R Stayrook
- Lilly Research Laboratories, Eli Lilly and Company , Indianapolis, Indiana
| | - Matthew R Allen
- Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
- Indiana Center for Musculoskeletal Health Indiana University School of Medicine , Indianapolis, Indiana
- Roudebush Veterans Administration Medical Center , Indianapolis, Indiana
| | - Joseph M Wallace
- Department of Orthopaedic Surgery, Indiana University School of Medicine , Indianapolis, Indiana
- Indiana Center for Musculoskeletal Health Indiana University School of Medicine , Indianapolis, Indiana
- Department of Biomedical Engineering, Indiana University-Purdue University , Indianapolis, Indiana
| | - Joseph P Bidwell
- Department of Medical and Molecular Genetics, Indiana University School of Medicine , Indianapolis, Indiana
- Department of Anatomy and Cell Biology, Indiana University School of Medicine , Indianapolis, Indiana
- Indiana Center for Musculoskeletal Health Indiana University School of Medicine , Indianapolis, Indiana
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75
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Salari Lak Y, Khorram S, Mesgari Abbasi M, Asghari-Jafarabadi M, Tarighat-Esfanjani A, Bazri E, Omidi H. The effects of natural nano-sized clinoptilolite and Nigella sativa supplementation on serum bone markers in diabetic rats. ACTA ACUST UNITED AC 2019; 9:173-178. [PMID: 31508332 PMCID: PMC6726750 DOI: 10.15171/bi.2019.21] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 01/25/2019] [Accepted: 01/25/2019] [Indexed: 11/24/2022]
Abstract
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Introduction: Many studies confirm that diabetes mellitus is associated with higher risks of bone fracture. The beneficial effects of Nigella sativa (NS) and clinoptilolite in preventing/reducing some diabetes-related disorders have been shown. This study was conducted to examine the effects of separate and concurrent supplementation of natural nano-sized clinoptilolite (NCLN) and NS on serum bone markers in rats with type 2 diabetes.
Methods: A total of 42 (case=36 and control=6) adult male Wistar rats were divided into 2 groups: diabetic and non-diabetic. An oral glucose tolerance test and a homeostatic model assessment of insulin resistance (HOMA-IR) test were conducted to confirm diabetes. Then, the diabetic group was divided into 4 subgroups: [1] control (n=9), [2] NS 1%/food (n=9), [3] NCLN 2%/food (n=9), [4] NS 1%/food + NCLN 2%/food (n=9). After 7 weeks, serum levels of bone markers were determined using ELISA kits.
Results: Analysis showed that serum levels of alkaline phosphatase (ALP) in the NCLN group (1318.6 ± 217.5 U/L) was significantly (P<0.05) higher than other intervented groups. On the other hand, serum levels of calcium in NCLN+NS group (10.8 ± 2.6 mg/dL) were higher (P=0.027) compared to all other study groups. However, rats in the NS group had higher (535.8 ± 49.3 pg/mL) PTH (P<0.0001) compared to other supplementation groups. There were no significant differences in vitamin D and osteoprotegerin.
Conclusion: The results of the current study suggest that bone mineralization may be affected by concurrent use of NS and NCLN through influencing calcium circulation. Moreover, dietary NS administration is strongly related to an augmented level of PTH.
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Affiliation(s)
- Yalda Salari Lak
- Student Research Committee, School of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Sirous Khorram
- Plasma group,Research Institute for Applied Physics and Astronomy (RIAPA), University of Tabriz, Tabriz, Iran
| | | | | | - Ali Tarighat-Esfanjani
- Nutrition Research Center, School of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Elahe Bazri
- Student Research Committee, School of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Hossein Omidi
- Student Research Committee, School of Nutrition and Food Sciences, Tabriz University of Medical Sciences, Tabriz, Iran
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76
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Glucose Restriction Promotes Osteocyte Specification by Activating a PGC-1α-Dependent Transcriptional Program. iScience 2019; 15:79-94. [PMID: 31039455 PMCID: PMC6488568 DOI: 10.1016/j.isci.2019.04.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 01/16/2019] [Accepted: 04/08/2019] [Indexed: 12/16/2022] Open
Abstract
Osteocytes, the most abundant of bone cells, differentiate while they remain buried within the bone matrix. This encasement limits their access to nutrients and likely affects their differentiation, a process that remains poorly defined. Here, we show that restriction in glucose supply promotes the osteocyte transcriptional program while also being associated with increased mitochondrial DNA levels. Glucose deprivation triggered the activation of the AMPK/PGC-1 pathway. AMPK and SIRT1 activators or PGC-1α overexpression are sufficient to enhance osteocyte gene expression in IDG-SW3 cells, murine primary osteoblasts, osteocytes, and organotypic/ex vivo bone cultures. Conversely, osteoblasts and osteocytes deficient in Ppargc1a and b were refractory to the effects of glucose restriction. Finally, conditional ablation of both genes in osteoblasts and osteocytes generate osteopenia and reduce osteocytic gene expression in mice. Altogether, we uncovered a role for PGC-1 in the regulation of osteocyte gene expression.
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77
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Abstract
PURPOSE OF REVIEW Proper cartilage development is critical to bone formation during endochondral ossification. This review highlights the current understanding of various aspects of glucose metabolism in chondrocytes during cartilage development. RECENT FINDINGS Recent studies indicate that chondrocytes transdifferentiate into osteoblasts and bone marrow stromal cells during endochondral ossification. In cartilage development, signaling molecules, including IGF2 and BMP2, tightly control glucose uptake and utilization in a stage-specific manner. Perturbation of glucose metabolism alters the course of chondrocyte maturation, suggesting a key role for glucose metabolism during endochondral ossification. During prenatal and postnatal growth, chondrocytes experience bursts of nutrient availability and energy expenditure, which demand sophisticated control of the glucose-dependent processes of cartilage matrix production, cell proliferation, and hypertrophy. Investigating the regulation of glucose metabolism may therefore lead to a unifying mechanism for signaling events in cartilage development and provide insight into causes of skeletal growth abnormalities.
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Affiliation(s)
- Judith M Hollander
- Program in Cell, Molecular, and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, 02111, USA
| | - Li Zeng
- Program in Cell, Molecular, and Developmental Biology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, 02111, USA.
- Program of Pharmacology and Experimental Therapeutics, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, 02111, USA.
- Program of Immunology, Sackler School of Graduate Biomedical Sciences, Tufts University, Boston, MA, 02111, USA.
- Department of Immunology, Tufts University School of Medicine, Boston, MA, 02111, USA.
- Department of Orthopaedics, Tufts Medical Center, Boston, MA, 02111, USA.
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78
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Chen H, Ji X, Lee WC, Shi Y, Li B, Abel ED, Jiang D, Huang W, Long F. Increased glycolysis mediates Wnt7b-induced bone formation. FASEB J 2019; 33:7810-7821. [PMID: 30913395 DOI: 10.1096/fj.201900201rr] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Wingless/integrated (Wnt) signaling has emerged as a major mechanism for promoting bone formation and a target pathway for developing bone anabolic agents against osteoporosis. However, the downstream events mediating the potential therapeutic effect of Wnt proteins are not fully understood. Previous studies have indicated that increased glycolysis is associated with osteoblast differentiation in response to Wnt signaling, but direct genetic evidence for the importance of glucose metabolism in Wnt-induced bone formation is lacking. Here, we have generated compound transgenic mice to overexpress Wnt family member 7B (Wnt7b) transiently in the osteoblast lineage of postnatal mice, with or without concurrent deletion of the glucose transporter 1 (Glut1), also known as solute carrier family 2, facilitated glucose transporter member 1. Overexpression of Wnt7b in 1-mo-old mice for 1 wk markedly stimulated bone formation, but the effect was essentially abolished without Glut1, even though transient deletion of Glut1 itself did not affect normal bone accrual. Consistent with the in vivo results, Wnt7b increased Glut1 expression and glucose consumption in the primary culture of osteoblast lineage cells, and deletion of Glut1 diminished osteoblast differentiation in vitro. Thus, Wnt7b promotes bone formation in part through stimulating glucose metabolism in osteoblast lineage cells.-Chen, H., Ji, X., Lee, W.-C., Shi, Y., Li, B., Abel, E. D., Jiang, D., Huang, W., Long, F. Increased glycolysis mediates Wnt7b-induced bone formation.
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Affiliation(s)
- Hong Chen
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China.,Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Xing Ji
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Wen-Chih Lee
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Yu Shi
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - Boer Li
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
| | - E Dale Abel
- Division of Endocrinology and Metabolism, Fraternal Order of Eagles Diabetes Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | - Dianming Jiang
- Department of Orthopedics, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Huang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Fanxin Long
- Department of Orthopedic Surgery, School of Medicine, Washington University, St. Louis, Missouri, USA
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79
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Pal S, Maurya SK, Chattopadhyay S, Pal China S, Porwal K, Kulkarni C, Sanyal S, Sinha RA, Chattopadhyay N. The osteogenic effect of liraglutide involves enhanced mitochondrial biogenesis in osteoblasts. Biochem Pharmacol 2019; 164:34-44. [PMID: 30885766 DOI: 10.1016/j.bcp.2019.03.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 03/14/2019] [Indexed: 12/31/2022]
Abstract
Liraglutide (Lira), a long-acting glucagon-like peptide 1 receptor (GLP1R) agonist reduces glycosylated hemoglobin in type 2 diabetes mellitus patients. Lira is reported to have bone conserving effect in ovariectomized (OVX) rats. Here, we investigated the osteoanabolic effect of Lira and studied the underlying mechanism. In established osteopenic OVX rats, Lira completely restored bone mass and strength comparable to parathyroid hormone (PTH 1-34). Body mass index normalized bone mineral density of Lira was higher than PTH. The serum levels of osteogenic surrogate pro-collagen type 1 N-terminal pro-peptide (P1NP) and surface referent bone formation parameters were comparable between Lira and PTH. GLP1R, adiponectin receptor 1 (AdipoR1) and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) levels in bones were downregulated in the OVX group but restored in the Lira group whereas PTH had no effect. In cultured osteoblasts, Lira time-dependently increased GLP1R, AdipoR1 and PGC1α expression. In osteoblasts, Lira rapidly phosphorylated AMP-dependent protein kinase (AMPK), the cellular energy sensor. Exendin 3, a selective GLP1R antagonist and PKA inhibitor H89 blocked Lira-induced increases in osteoblast differentiation, and expression levels of AdipoR1 and PGC1α. Furthermore, H89 inhibited Lira-induced phosphorylation of AMPK and dorsomorphin, an AMPK inhibitor blocked the Lira-induced increases in osteoblast differentiation and AdipoR1 and PGC1α levels. Lira increased mitochondrial number, respiratory proteins and respiration in osteoblasts in vitro and in vivo, and blocking mitochondrial respiration mitigated Lira-induced osteoblast differentiation. Taken together, our data show that Lira has a strong osteoanabolic effect which involves upregulation of mitochondrial function.
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Affiliation(s)
- Subhashis Pal
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Shailendra K Maurya
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Sourav Chattopadhyay
- Division of Biochemistry, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Shyamsundar Pal China
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Konica Porwal
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Chirag Kulkarni
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India
| | - Sabyasachi Sanyal
- Division of Biochemistry, Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Rohit A Sinha
- Department of Endocrinology, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow 226014, India
| | - Naibedya Chattopadhyay
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India.
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80
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Maridas DE, Rendina-Ruedy E, Helderman RC, DeMambro VE, Brooks D, Guntur AR, Lanske B, Bouxsein ML, Rosen CJ. Progenitor recruitment and adipogenic lipolysis contribute to the anabolic actions of parathyroid hormone on the skeleton. FASEB J 2019; 33:2885-2898. [PMID: 30354669 PMCID: PMC6338651 DOI: 10.1096/fj.201800948rr] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Accepted: 09/24/2018] [Indexed: 12/13/2022]
Abstract
Intermittent administration of parathyroid hormone (PTH) stimulates bone formation in vivo and also suppresses the volume of bone marrow adipose tissue (BMAT). In contrast, a calorie-restricted (CR) diet causes bone loss and induces BMAT in both mice and humans. We used the CR model to test whether PTH would reduce BMAT in mice by both altering cell fate and inducing lipolysis of marrow adipocytes. Eight-week-old mice were placed on a control (Ctrl) diet or CR diet. At 12 wk, CR and Ctrl mice were injected daily with PTH (CR/PTH or Ctrl/PTH) or vehicle for 4 wk. Two other cohorts were CR and simultaneously injected (CR + PTH or CR + Veh) for 4 wk. CR mice had low bone mass and increased BMAT in the proximal tibias. PTH significantly increased bone mass in all cohorts despite calorie restrictions. Adipocyte density and size were markedly increased with restriction of calories. PTH reduced adipocyte numbers in CR + PTH mice, whereas adipocyte size was reduced in CR/PTH-treated mice. In contrast, osteoblast number was increased 3-8-fold with PTH treatment. In vitro, bone marrow stromal cells differentiated into adipocytes and, treated with PTH, exhibited increased production of glycerol and fatty acids. Moreover, in cocultures of bone marrow adipocyte and osteoblast progenitors, PTH stimulated the transfer of fatty acids to osteoblasts. In summary, PTH administration to CR mice increased bone mass by shifting lineage allocation toward osteogenesis and inducing lipolysis of mature marrow adipocytes. The effects of PTH on bone marrow adiposity could enhance its anabolic actions by providing both more cells and more fuel for osteoblasts during bone formation.-Maridas, D. E., Rendina-Ruedy, E., Helderman, R. C., DeMambro, V. E., Brooks, D., Guntur, A. R., Lanske, B., Bouxsein, M. L., Rosen, C. J. Progenitor recruitment and adipogenic lipolysis contribute to the anabolic actions of parathyroid hormone on the skeleton.
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Affiliation(s)
- David E. Maridas
- Maine Medical Center Research Institute, Scarborough, Maine, USA
- Harvard School of Dental Medicine, Boston, Massachusetts, USA; and
| | | | - Ron C. Helderman
- Maine Medical Center Research Institute, Scarborough, Maine, USA
| | | | - Daniel Brooks
- Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
| | | | - Beate Lanske
- Harvard School of Dental Medicine, Boston, Massachusetts, USA; and
| | - Mary L. Bouxsein
- Center for Advanced Orthopaedic Studies, Beth Israel Deaconess Medical Center, Boston, Massachusetts, USA
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81
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Glucose metabolism induced by Bmp signaling is essential for murine skeletal development. Nat Commun 2018; 9:4831. [PMID: 30446646 PMCID: PMC6240091 DOI: 10.1038/s41467-018-07316-5] [Citation(s) in RCA: 82] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 10/24/2018] [Indexed: 02/08/2023] Open
Abstract
Much of the mammalian skeleton originates from a cartilage template eventually replaced by bone via endochondral ossification. Despite much knowledge about growth factors and nuclear proteins in skeletal development, little is understood about the role of metabolic regulation. Here we report that genetic deletion of the glucose transporter Glut1 (Slc2a1), either before or after the onset of chondrogenesis in the limb, severely impairs chondrocyte proliferation and hypertrophy, resulting in dramatic shortening of the limbs. The cartilage defects are reminiscent to those caused by deficiency in Bmp signaling. Importantly, deletion of Bmpr1a in chondrocytes markedly reduces Glut1 levels in vivo, whereas recombinant BMP2 increases Glut1 mRNA and protein levels, boosting glucose metabolism in primary chondrocytes. Biochemical studies identify a Bmp-mTORC1-Hif1a signaling cascade resulting in upregulation of Glut1 in chondrocytes. The results therefore uncover a hitherto unknown connection between Bmp signaling and glucose metabolism in the regulation of cartilage development. It is unclear how metabolic regulation affects development of the skeleton. Here, the authors show that deletion of the glucose transporter Glut1 (Slc2a1) both prior to and following chondrogenesis in the mouse limb impairs chondrocyte proliferation and shortening of the limbs, modulated by BMP signaling.
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82
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Lee SY, Long F. Notch signaling suppresses glucose metabolism in mesenchymal progenitors to restrict osteoblast differentiation. J Clin Invest 2018; 128:5573-5586. [PMID: 30284985 DOI: 10.1172/jci96221] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 10/02/2018] [Indexed: 01/02/2023] Open
Abstract
Notch signaling critically controls cell fate decisions in mammals, both during embryogenesis and in adults. In the skeleton, Notch suppresses osteoblast differentiation and sustains bone marrow mesenchymal progenitors during postnatal life. Stabilizing mutations of Notch2 cause Hajdu-Cheney syndrome, which is characterized by early-onset osteoporosis in humans, but the mechanism whereby Notch inhibits bone accretion is not fully understood. Here, we report that activation of Notch signaling by either Jagged1 or the Notch2 intracellular domain suppresses glucose metabolism and osteoblast differentiation in primary cultures of bone marrow mesenchymal progenitors. Importantly, deletion of Notch2 in the limb mesenchyme increases both glycolysis and bone formation in the long bones of postnatal mice, whereas pharmacological reduction of glycolysis abrogates excessive bone formation. Mechanistically, Notch reduces the expression of glycolytic and mitochondrial complex I genes, resulting in a decrease in mitochondrial respiration, superoxide production, and AMPK activity. Forced activation of AMPK restores glycolysis in the face of Notch signaling. Thus, suppression of glucose metabolism contributes to the mechanism, whereby Notch restricts osteoblastogenesis from bone marrow mesenchymal progenitors.
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Affiliation(s)
| | - Fanxin Long
- Department of Orthopaedic Surgery, and.,Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, USA
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83
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Abstract
The emergence of bone as an endocrine organ able to influence whole body metabolism, together with comorbid epidemics of obesity, diabetes, and osteoporosis, have prompted a renewed interest in the intermediary metabolism of the osteoblast. To date, most studies have focused on the utilization of glucose by this specialized cell, but the oxidation of fatty acids results in a larger energy yield. Osteoblasts express the requisite receptors and catabolic enzymes to take up and then metabolize fatty acids, which appears to be required during later stages of differentiation when the osteoblast is dedicated to matrix production and mineralization. In this article, we provide an overview of fatty acid β-oxidation and highlight studies demonstrating that the skeleton plays a significant role in the clearance of circulating lipoproteins and non-esterified fatty acids. Additionally, we review the requirement for long-chain fatty acid metabolism during post-natal bone development and the effects of anabolic stimuli on fatty acid utilization by osteoblasts. These recent findings may help to explain the skeletal manifestations of human diseases associated with impaired lipid metabolism while also providing additional insights into the metabolic requirements of skeletal homeostasis.
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Affiliation(s)
- Priyanka Kushwaha
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Michael J Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Baltimore Veterans Administration Medical Center, Baltimore, MD, USA.
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84
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Abstract
The adult human skeleton is a multifunctional organ undergoing constant remodeling through the opposing activities of the bone-resorbing osteoclast and the bone-forming osteoblast. The exquisite balance between bone resorption and bone formation is responsible for bone homeostasis in healthy adults. However, evidence has emerged that such a balance is likely disrupted in diabetes where systemic glucose metabolism is dysregulated, resulting in increased bone frailty and osteoporotic fractures. These findings therefore underscore the significance of understanding the role and regulation of glucose metabolism in bone under both normal and pathological conditions. Recent studies have shed new light on the metabolic plasticity and the critical functions of glucose metabolism during osteoclast and osteoblast differentiation. Moreover, these studies have begun to identify intersections between glucose metabolism and the growth factors and transcription factors previously known to regulate osteoblasts and osteoclasts. Here we summarize the current knowledge in the nascent field, and suggest that a fundamental understanding of glucose metabolic pathways in the critical bone cell types may open new avenues for developing novel bone therapeutics.
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Affiliation(s)
- Courtney M Karner
- Department of Orthopaedic Surgery, Duke Orthopaedic Cellular, Developmental, and Genome Laboratories, Department of Cell Biology, Duke University School of Medicine, Durham, NC 27710, USA.
| | - Fanxin Long
- Department of Orthopaedic Surgery, Department of Developmental Biology, Washington University School of Medicine, St Louis, MO 63131, USA.
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85
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Zhang D, Bae C, Lee J, Lee J, Jin Z, Kang M, Cho YS, Kim JH, Lee W, Lim SK. The bone anabolic effects of irisin are through preferential stimulation of aerobic glycolysis. Bone 2018; 114:150-160. [PMID: 29775761 DOI: 10.1016/j.bone.2018.05.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 05/03/2018] [Accepted: 05/12/2018] [Indexed: 12/11/2022]
Abstract
Irisin, a recently identified hormone secreted by skeletal muscle in response to exercise, exhibits anabolic effects on the skeleton primarily through the stimulation of bone formation. However, the mechanism underlying the irisin-stimulated anabolic response remains largely unknown. To uncover the underlying mechanism, we biosynthesized recombinant irisin (r-irisin) using an Escherichia coli expression system and used it to treat several osteoblast cell types. Our synthesized r-irisin could promote proliferation and differentiation of osteoblasts as evidenced by enhanced expression of osteoblast-specific transcriptional factors, including Runt-related transcription factor-2 (Runx2), Oster (Osx), as well as early osteoblastic differentiation markers such as alkaline phosphatase (Alp) and collagen type I alpha 1 (Col1a1). Furthermore, we showed that the promotion of r-irisin on the proliferation and differentiation of osteoblast lineage cells are preferentially through aerobic glycolysis, as indicated by the enhanced abundance of representative enzymes such as lactate dehydrogenase A (LDHA) and pyruvate dehydrogenase kinase 1 (PDK1), together with increased lactate levels. Suppression of r-irisin-mediated aerobic glycolysis with Dichloroacetate blunted its anabolic effects. The favorite of the aerobic glycolysis after r-irisin treatment was then confirmed in primary calvarial cells by metabolic analysis using gas chromatography-mass spectrometry. Thus, our results suggest that the anabolic actions of r-irisin on the regulation of osteoblast lineage cells are preferentially through aerobic glycolysis, which may help to develop new irisin-based bone anabolic agents.
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Affiliation(s)
- Dongdong Zhang
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Republic of Korea; Division of Endocrinology & Metabolism, Department of Internal Medicine, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, People's Republic of China
| | - ChuHyun Bae
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Republic of Korea
| | - Junghak Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Jiho Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Zeyu Jin
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Myeongmo Kang
- Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Young Suk Cho
- Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea
| | - Jeong-Han Kim
- Department of Agricultural Biotechnology, Seoul National University, Seoul, Republic of Korea
| | - Weontae Lee
- Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, Republic of Korea
| | - Sung-Kil Lim
- Brain Korea 21 PLUS Project for Medical Science, Yonsei University, Seoul, Republic of Korea; Department of Internal Medicine, College of Medicine, Yonsei University, Seoul, Republic of Korea.
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86
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Liu DM, Mosialou I, Liu JM. Bone: Another potential target to treat, prevent and predict diabetes. Diabetes Obes Metab 2018; 20:1817-1828. [PMID: 29687585 DOI: 10.1111/dom.13330] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/08/2018] [Revised: 04/16/2018] [Accepted: 04/18/2018] [Indexed: 12/30/2022]
Abstract
Type 2 diabetes mellitus is now a worldwide health problem with increasing prevalence. Mounting efforts have been made to treat, prevent and predict this chronic disease. In recent years, increasing evidence from mice and clinical studies suggests that bone-derived molecules modulate glucose metabolism. This review aims to summarize our current understanding of the interplay between bone and glucose metabolism and to highlight potential new means of therapeutic intervention. The first molecule recognized as a link between bone and glucose metabolism is osteocalcin (OCN), which functions in its active form, that is, undercarboxylated OCN (ucOC). ucOC acts in promoting insulin expression and secretion, facilitating insulin sensitivity, and favouring glucose and fatty acid uptake and utilization. A second bone-derived molecule, lipocalin2, functions in suppressing appetite in mice through its action on the hypothalamus. Osteocytes, the most abundant cells in bone matrix, are suggested to act on the browning of white adipose tissue and energy expenditure through secretion of bone morphogenetic protein 7 and sclerostin. The involvement of bone resorption in glucose homeostasis has also been examined. However, there is evidence indicating the implication of the receptor activator of nuclear factor κ-B ligand, neuropeptide Y, and other known and unidentified bone-derived factors that function in glucose homeostasis. We summarize recent advances and the rationale for treating, preventing and predicting diabetes by skeleton intervention.
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Affiliation(s)
- Dong-Mei Liu
- Department of Rheumatology, ZhongShan Hospital, FuDan University, Shanghai, China
| | - Ioanna Mosialou
- Department of Physiology and Cellular Biophysics, College of Physicians and Surgeons, Columbia University, New York, New York
| | - Jian-Min Liu
- Department of Endocrine and Metabolic Diseases, Shanghai Clinical Center for Endocrine and Metabolic Diseases, Rui-jin Hospital, Shanghai Jiao-tong University School of Medicine, Shanghai Institute of Endocrine and Metabolic Diseases, Shanghai, China
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87
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Yakar S, Werner H, Rosen CJ. Insulin-like growth factors: actions on the skeleton. J Mol Endocrinol 2018; 61:T115-T137. [PMID: 29626053 PMCID: PMC5966339 DOI: 10.1530/jme-17-0298] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2018] [Accepted: 04/06/2018] [Indexed: 12/20/2022]
Abstract
The discovery of the growth hormone (GH)-mediated somatic factors (somatomedins), insulin-like growth factor (IGF)-I and -II, has elicited an enormous interest primarily among endocrinologists who study growth and metabolism. The advancement of molecular endocrinology over the past four decades enables investigators to re-examine and refine the established somatomedin hypothesis. Specifically, gene deletions, transgene overexpression or more recently, cell-specific gene-ablations, have enabled investigators to study the effects of the Igf1 and Igf2 genes in temporal and spatial manners. The GH/IGF axis, acting in an endocrine and autocrine/paracrine fashion, is the major axis controlling skeletal growth. Studies in rodents have clearly shown that IGFs regulate bone length of the appendicular skeleton evidenced by changes in chondrocytes of the proliferative and hypertrophic zones of the growth plate. IGFs affect radial bone growth and regulate cortical and trabecular bone properties via their effects on osteoblast, osteocyte and osteoclast function. Interactions of the IGFs with sex steroid hormones and the parathyroid hormone demonstrate the significance and complexity of the IGF axis in the skeleton. Finally, IGFs have been implicated in skeletal aging. Decreases in serum IGFs during aging have been correlated with reductions in bone mineral density and increased fracture risk. This review highlights many of the most relevant studies in the IGF research landscape, focusing in particular on IGFs effects on the skeleton.
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Affiliation(s)
- Shoshana Yakar
- David B. Kriser Dental Center, Department of Basic Science and Craniofacial Biology, New York University College of Dentistry, New York, NY 10010-4086, USA
| | - Haim Werner
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Scarborough, Maine 04074, USA
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88
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Wu Y, Wang M, Zhang K, Li Y, Xu M, Tang S, Qu X, Li C. Lactate enhanced the effect of parathyroid hormone on osteoblast differentiation via GPR81-PKC-Akt signaling. Biochem Biophys Res Commun 2018; 503:737-743. [PMID: 29913143 DOI: 10.1016/j.bbrc.2018.06.069] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 06/14/2018] [Indexed: 12/19/2022]
Abstract
Osteoblast uses aerobic glycolysis to meet the metabolic needs in differentiation process. Lactate, the end product of glycolysis, presents in the environment with elevated PTH and osteoblast differentiation. Although previous findings showed that lactate promoted osteoblast differentiation, whether lactate affects PTH-mediated osteoblast differentiation is unclear. To investigate this, pre-osteoblast cell line MC3T3-E1 was treated PTH with or without physiological dose of lactate. Lactate increases ALP positive cell formation, increases ALP activity and expression of differentiation related markers, enriches the CREB transcriptional factor target genes in PTH treated cells. Using inhibitors for MCT-1 reveales that lactate effects are MCT-1 independent. Lactate selectively increases Akt and p38 activation but not Erk1/2 and β-Catenin activation. The inhibitors for Akt and p38 inhibit lactate effects on PTH mediated osteoblast differentiation. Using inhibitors for Gαi signaling of GPR81 further increases Alp mRNA levels in lactate and PTH co-treatment cells. However, with the inhibitors for Gβγ-PLC-PKC signaling, the effect of lactate on PTH mediated osteoblast differentiation is inhibited. Our data demonstrate that lactate activates GPR81-Gβγ-PLC-PKC-Akt signaling to regulate osteoblast differentiation that mediated by PTH treatment.
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Affiliation(s)
- Yu Wu
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China.
| | - Miaomiao Wang
- Department of Occupational Health, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, China
| | - Kefan Zhang
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China
| | - Yingjiang Li
- The Second Wuxi affiliated hospital of Nanjing Medical University, Nanjing Medical University, Jiangsu, China
| | - Manlin Xu
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China
| | - Shaidi Tang
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China
| | - Xiuxia Qu
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China
| | - Chunping Li
- Department of Occupational Health, Wuxi Center for Disease Control and Prevention, Wuxi, Jiangsu, China.
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89
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Wang T, Han C, Tian P, Li PF, Ma XL. Role of Teriparatide in Glucocorticoid-induced Osteoporosis through Regulating Cellular Reactive Oxygen Species. Orthop Surg 2018; 10:152-159. [PMID: 29745033 DOI: 10.1111/os.12369] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 01/25/2018] [Indexed: 12/25/2022] Open
Abstract
OBJECTIVE To determine the signaling pathways mediated by teriparatide in MLO-Y4 cell lines based on the evaluation of reactive oxygen species (ROS) through AKT pathways, which regulate apoptosis of bone cells. METHODS We performed the DCFH-DA assay to investigate the role of ROS in MLO-Y4 cells caused by dexamethasone (Dex). Four groups were included: Dex group, Dex+NAC, Dex+ teriparatide group and control group (without any dispose). Real-time reverse transcriptase polymerase chain reaction was used to test the SOD2 and Cat mRNA expression. Western blot (WB) was used to investigate the AKT and caspase-3 protein expression. A Cell Counting Kit-8 (CCK-8) assay test was conducted to explore the cell viability, and we also studied the apoptosis through western blot assay. A glucocorticoid-induced osteoporosis (GIOP) model was used to confirm the anti-ROS and anti-apoptosis ability of teriparatide. RESULTS The CCK-8 assay revealed that Dex reduced the proliferative capability of cells significantly, whereas incubation with teriparatide resulted in a remarkable increase in the proliferation of osteocytes. In addition, teriparatide can rescue the effect of inhibiting cell proliferation due to Dex treatment. Immunofluorescence analysis showed that ROS levels increased in Dex-treated MLO-Y4 cells when compared with control groups. However, the Dex+Teriparatide group showed less ROS when compared with the Dex group. The expression of Sod2 and Cat, two antioxidant enzymes crucial for ROS elimination, was decreased in the Dex group, indicating a defect of the enzymatic antioxidant system. Compared to the Dex group, incubation with teriparatide resulted in a significant decrease in caspase-3 level; when compared with the control group, the caspase-3 level was not significantly different, indicating that teriparatide can rescue apoptosis during Dex exposure. Moreover, teriparatide promotes the expression of AKT, and rescues the apoptosis effect caused by Dex. The results of immunofluorescence also showed that Akt was highly expressed in the teriparatide group when compared with the Dex group. The microstructural parameters Tb.Th, BV/TV, and Tb.N in the methylprednisolone (MPS) group were markedly reduced compared with the control group, but additional treatment with teriparatide could remarkably reverse the methylprednisolone-induced reduction of these parameters. Moreover, the parameter Tb.Sp was significantly increased in the methylprednisolone group compared to the control group, and this increase could be inhibited by teriparatide. CONCLUSIONS Teriparatide can reduce the cellular ROS level caused by glucocorticoids to facilitate the proliferation of osteocytes through activating the AKT pathway. Meanwhile, the activated AKT can inhibit the activity of proteolytic enzyme caspase-3 and prevent the activation of apoptosis cascade.
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Affiliation(s)
- Tao Wang
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin, China.,Department of Orthopaedics, Tianjin Hospital, Tianjin, China
| | - Chao Han
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Peng Tian
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Peng-Fei Li
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin, China
| | - Xin-Long Ma
- Department of Orthopaedics, Tianjin Medical University General Hospital, Tianjin, China.,Department of Orthopaedics, Tianjin Hospital, Tianjin, China
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90
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Dirckx N, Tower RJ, Mercken EM, Vangoitsenhoven R, Moreau-Triby C, Breugelmans T, Nefyodova E, Cardoen R, Mathieu C, Van der Schueren B, Confavreux CB, Clemens TL, Maes C. Vhl deletion in osteoblasts boosts cellular glycolysis and improves global glucose metabolism. J Clin Invest 2018; 128:1087-1105. [PMID: 29431735 DOI: 10.1172/jci97794] [Citation(s) in RCA: 65] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 12/28/2017] [Indexed: 01/05/2023] Open
Abstract
The skeleton has emerged as an important regulator of systemic glucose homeostasis, with osteocalcin and insulin representing prime mediators of the interplay between bone and energy metabolism. However, genetic evidence indicates that osteoblasts can influence global energy metabolism through additional, as yet unknown, mechanisms. Here, we report that constitutive or postnatally induced deletion of the hypoxia signaling pathway component von Hippel-Lindau (VHL) in skeletal osteolineage cells of mice led to high bone mass as well as hypoglycemia and increased glucose tolerance, not accounted for by osteocalcin or insulin. In vitro and in vivo data indicated that Vhl-deficient osteoblasts displayed massively increased glucose uptake and glycolysis associated with upregulated HIF-target gene expression, resembling the Warburg effect that typifies cancer cells. Overall, the glucose consumption by the skeleton was increased in the mutant mice, as revealed by 18F-FDG radioactive tracer experiments. Moreover, the glycemia levels correlated inversely with the level of skeletal glucose uptake, and pharmacological treatment with the glycolysis inhibitor dichloroacetate (DCA), which restored glucose metabolism in Vhl-deficient osteogenic cells in vitro, prevented the development of the systemic metabolic phenotype in the mutant mice. Altogether, these findings reveal a novel link between cellular glucose metabolism in osteoblasts and whole-body glucose homeostasis, controlled by local hypoxia signaling in the skeleton.
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Affiliation(s)
- Naomi Dirckx
- Laboratory of Skeletal Cell Biology and Physiology (SCEBP), Skeletal Biology and Engineering Research Center (SBE), KU Leuven, Leuven, Belgium
| | - Robert J Tower
- Laboratory of Skeletal Cell Biology and Physiology (SCEBP), Skeletal Biology and Engineering Research Center (SBE), KU Leuven, Leuven, Belgium
| | - Evi M Mercken
- Laboratory of Skeletal Cell Biology and Physiology (SCEBP), Skeletal Biology and Engineering Research Center (SBE), KU Leuven, Leuven, Belgium
| | | | | | - Tom Breugelmans
- Laboratory of Skeletal Cell Biology and Physiology (SCEBP), Skeletal Biology and Engineering Research Center (SBE), KU Leuven, Leuven, Belgium
| | - Elena Nefyodova
- Laboratory of Skeletal Cell Biology and Physiology (SCEBP), Skeletal Biology and Engineering Research Center (SBE), KU Leuven, Leuven, Belgium
| | - Ruben Cardoen
- Laboratory of Skeletal Cell Biology and Physiology (SCEBP), Skeletal Biology and Engineering Research Center (SBE), KU Leuven, Leuven, Belgium
| | - Chantal Mathieu
- Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | | | - Cyrille B Confavreux
- INSERM UMR1033 - LYOS, Université de Lyon, Lyon, France.,Department of Rheumatology, Hospices Civils de Lyon, Lyon, France
| | - Thomas L Clemens
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
| | - Christa Maes
- Laboratory of Skeletal Cell Biology and Physiology (SCEBP), Skeletal Biology and Engineering Research Center (SBE), KU Leuven, Leuven, Belgium
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91
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Prisby RD. Mechanical, hormonal and metabolic influences on blood vessels, blood flow and bone. J Endocrinol 2017; 235:R77-R100. [PMID: 28814440 PMCID: PMC5611884 DOI: 10.1530/joe-16-0666] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 08/16/2017] [Indexed: 12/25/2022]
Abstract
Bone tissue is highly vascularized due to the various roles bone blood vessels play in bone and bone marrow function. For example, the vascular system is critical for bone development, maintenance and repair and provides O2, nutrients, waste elimination, systemic hormones and precursor cells for bone remodeling. Further, bone blood vessels serve as egress and ingress routes for blood and immune cells to and from the bone marrow. It is becoming increasingly clear that the vascular and skeletal systems are intimately linked in metabolic regulation and physiological and pathological processes. This review examines how agents such as mechanical loading, parathyroid hormone, estrogen, vitamin D and calcitonin, all considered anabolic for bone, have tremendous impacts on the bone vasculature. In fact, these agents influence bone blood vessels prior to influencing bone. Further, data reveal strong associations between vasodilator capacity of bone blood vessels and trabecular bone volume, and poor associations between estrogen status and uterine mass and trabecular bone volume. Additionally, this review highlights the importance of the bone microcirculation, particularly the vascular endothelium and NO-mediated signaling, in the regulation of bone blood flow, bone interstitial fluid flow and pressure and the paracrine signaling of bone cells. Finally, the vascular endothelium as a mediator of bone health and disease is considered.
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Affiliation(s)
- Rhonda D Prisby
- Department of KinesiologyUniversity of Texas at Arlington, Arlington, Texas, USA
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92
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China SP, Pal S, Chattopadhyay S, Porwal K, Kushwaha S, Bhattacharyya S, Mittal M, Gurjar AA, Barbhuyan T, Singh AK, Trivedi AK, Gayen JR, Sanyal S, Chattopadhyay N. Globular adiponectin reverses osteo-sarcopenia and altered body composition in ovariectomized rats. Bone 2017; 105:75-86. [PMID: 28811200 DOI: 10.1016/j.bone.2017.08.005] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2017] [Revised: 08/01/2017] [Accepted: 08/11/2017] [Indexed: 01/13/2023]
Abstract
Adiponectin regulates various metabolic processes including glucose flux, lipid breakdown and insulin response. We recently reported that adiponectin receptor1 (adipoR1) activation by a small molecule reverses osteopenia in leptin receptor deficient db/db (diabetic) mice. However, the role of adiponectin in bone metabolism under the setting of post-menopausal (estrogen-deficiency) osteopenia and associated metabolic derangements has not been studied. Here, we studied the therapeutic effect of the globular form of adiponectin (gAd), which is predominantly an adipoR1 agonist, in aged ovariectomized (OVX) rats and compared it with standard-of-care anti-osteoporosis drugs. In OVX rats with established osteopenia, gAd completely restored BMD and load bearing capacity and improved bone quality. Skeletal effects of gAd were comparable to PTH (osteoanabolic) but better than alendronate (anti-catabolic). Both osteoanabolic and anti-catabolic mechanisms led to the anti-osteoporosis effect of gAd. In cultured osteoblasts and bones, gAd increased a) adipoR1 and peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC1α) expression to promote mitochondrial respiration, which likely fueled osteoblast differentiation, b) suppressed sclerostin (a wnt antagonist) in a sirtuin1-dependent manner and c) decreased receptor-activator of nuclear factor κB ligand (RANKL) to achieve its anti-catabolic effect. The OVX-induced sarcopenia and insulin resistance were also improved by gAd. We conclude that gAd has therapeutic efficacy in estrogen deficiency-induced osteoporosis, sarcopenia and insulin resistance and hold metabolic disease modifying potential in postmenopausal women.
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Affiliation(s)
- Shyamsundar Pal China
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India
| | - Subhashis Pal
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Sourav Chattopadhyay
- AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India; Division of Biochemistry, CSIR-CDRI, Lucknow 226031, India
| | - Konica Porwal
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | | | - Sharmishtha Bhattacharyya
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | - Monika Mittal
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India
| | - Anagha A Gurjar
- AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India; Division of Biochemistry, CSIR-CDRI, Lucknow 226031, India
| | - Tarun Barbhuyan
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India
| | | | - Arun K Trivedi
- Division of Biochemistry, CSIR-CDRI, Lucknow 226031, India
| | - Jiaur R Gayen
- Division of Pharmacokinetics and Metabolism, CSIR-CDRI, Lucknow 226031, India
| | - Sabyasachi Sanyal
- AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India; Division of Biochemistry, CSIR-CDRI, Lucknow 226031, India.
| | - Naibedya Chattopadhyay
- Division of Endocrinology and Center for Research in Anabolic Skeletal Target in Health and Illness (ASTHI), Central Drug Research Institute (CDRI), Council of Scientific and Industrial Research (CSIR), Lucknow 226031, India; AcSIR, CSIR-Central Drug Research Institute Campus, Lucknow 226031, India.
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93
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Yu M, D'Amelio P, Tyagi AM, Vaccaro C, Li JY, Hsu E, Buondonno I, Sassi F, Adams J, Weitzmann MN, DiPaolo R, Pacifici R. Regulatory T cells are expanded by Teriparatide treatment in humans and mediate intermittent PTH-induced bone anabolism in mice. EMBO Rep 2017; 19:156-171. [PMID: 29158349 DOI: 10.15252/embr.201744421] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 10/03/2017] [Accepted: 10/17/2017] [Indexed: 12/16/2022] Open
Abstract
Teriparatide is a bone anabolic treatment for osteoporosis, modeled in animals by intermittent PTH (iPTH) administration, but the cellular and molecular mechanisms of action of iPTH are largely unknown. Here, we show that Teriparatide and iPTH cause a ~two-threefold increase in the number of regulatory T cells (Tregs) in humans and mice. Attesting in vivo relevance, blockade of the Treg increase in mice prevents the increase in bone formation and trabecular bone volume and structure induced by iPTH Therefore, increasing the number of Tregs is a pivotal mechanism by which iPTH exerts its bone anabolic activity. Increasing Tregs pharmacologically may represent a novel bone anabolic therapy, while iPTH-induced Treg increase may find applications in inflammatory conditions and transplant medicine.
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Affiliation(s)
- Mingcan Yu
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Patrizia D'Amelio
- Gerontology Section, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Abdul Malik Tyagi
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Chiara Vaccaro
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Jau-Yi Li
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Emory Hsu
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA
| | - Ilaria Buondonno
- Gerontology Section, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Francesca Sassi
- Gerontology Section, Department of Medical Sciences, University of Torino, Torino, Italy
| | - Jonathan Adams
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA
| | - M Neale Weitzmann
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA.,Atlanta Department of Veterans Affairs Medical Center, Decatur, GA, USA
| | - Richard DiPaolo
- Department of Molecular Microbiology & Immunology, Saint Louis University School of Medicine, St. Louis, MO, USA
| | - Roberto Pacifici
- Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA .,Immunology and Molecular Pathogenesis Program, Emory University, Atlanta, GA, USA
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94
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Wu Y, Wang M, Feng H, Peng Y, Sun J, Qu X, Li C. Lactate induces osteoblast differentiation by stabilization of HIF1α. Mol Cell Endocrinol 2017; 452:84-92. [PMID: 28536031 DOI: 10.1016/j.mce.2017.05.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Revised: 05/07/2017] [Accepted: 05/16/2017] [Indexed: 01/07/2023]
Abstract
Aerobic glycolysis is involved in osteoblast differentiation induced by Wnt signaling or PTH treatment. However, it is still unclear whether lactate, the end product of aerobic glycolysis, plays any role in osteoblast differentiation. Herein we report that in cultures of osteoblast-lineage cells, lactate promoted alkaline phosphatase-positive cell formation, increased the activity of alkaline phosphatase, and induced the expression of osteocalcin. This osteoblast differentiation-inducing effect of lactate can be inhibited by blocking its entry into cells with MCT1 siRNA or inhibitors, and by interfering with its metabolism by using specific siRNAs for LDHB and PDH. Moreover, lactate stabilized HIF1α expression and inhibited HIF1α activity, with BAY87-2243 lowering the osteoblast differentiation-inducing effect of lactate. Thus, these findings reveal an unrecognized role for aerobic glycolysis in osteoblast differentiation via its end product, lactate.
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Affiliation(s)
- Yu Wu
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China.
| | - Miaomiao Wang
- Department of Occupational Health, Wuxi Center for Disease Control, Wuxi, Jiangsu, China
| | - Haihua Feng
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China
| | - Ying Peng
- Key Laboratory of Nuclear Medicine, Ministry of Health, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, Wuxi, Jiangsu, China
| | - Jieyun Sun
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China
| | - Xiuxia Qu
- Lab of Molecular and Cellular Biology, Wuxi Medical School, Jiangnan University, Wuxi, Jiangsu, China
| | - Chunping Li
- Department of Occupational Health, Wuxi Center for Disease Control, Wuxi, Jiangsu, China
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95
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O' Brien MH, Dutra EH, Lima A, Nanda R, Yadav S. PTH [1-34] induced differentiation and mineralization of mandibular condylar cartilage. Sci Rep 2017; 7:3226. [PMID: 28607469 PMCID: PMC5468307 DOI: 10.1038/s41598-017-03428-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2016] [Accepted: 04/28/2017] [Indexed: 12/26/2022] Open
Abstract
Intermittent Parathyroid Hormone (I-PTH) is the only FDA approved anabolic drug therapy available for the treatment of osteoporosis in males and postmenopausal females. The effects of I-PTH on the chondrogenic lineage of the mandibular condylar cartilage (MCC) are not well understood. To investigate the role of I-PTH on the MCC and subchondral bone, we carried out our studies using 4 to 5 week old triple transgenic mice (Col1a1XCol2a1XCol10a1). The experimental group was injected with PTH (80 μg/kg) daily for 2 weeks, while control group was injected with saline. Our histology showed that the I-PTH treatment led to an increased number of cells expressing Col1a1, Col2a1 and Col10a1. Additionally, there was an increase in cellular proliferation, increased proteoglycan distribution, increased cartilage thickness, increased TRAP activity, and mineralization. Immunohistochemical staining showed increased expression of pSMAD158 and VEGF in the MCC and subchondral bone. Furthermore our microCT data showed that I-PTH treatment led to an increased bone volume fraction, tissue density and trabecular thickness, with a decrease in trabecular spacing. Morphometric measurements showed increased mandibular length and condyle head length following I-PTH treatment. In conclusion, our study suggests that I-PTH plays a critical role in cellular proliferation, proteoglycan distribution, and mineralization of the MCC.
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Affiliation(s)
- Mara Heather O' Brien
- Division of Orthodontics, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Eliane Hermes Dutra
- Division of Orthodontics, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Alexandro Lima
- Division of Orthodontics, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Ravindra Nanda
- Division of Orthodontics, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, 06030, USA
| | - Sumit Yadav
- Division of Orthodontics, University of Connecticut Health Center, 263 Farmington Ave, Farmington, CT, 06030, USA.
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96
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Lee WC, Guntur AR, Long F, Rosen CJ. Energy Metabolism of the Osteoblast: Implications for Osteoporosis. Endocr Rev 2017; 38:255-266. [PMID: 28472361 PMCID: PMC5460680 DOI: 10.1210/er.2017-00064] [Citation(s) in RCA: 261] [Impact Index Per Article: 37.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 04/25/2017] [Indexed: 01/14/2023]
Abstract
Osteoblasts, the bone-forming cells of the remodeling unit, are essential for growth and maintenance of the skeleton. Clinical disorders of substrate availability (e.g., diabetes mellitus, anorexia nervosa, and aging) cause osteoblast dysfunction, ultimately leading to skeletal fragility and osteoporotic fractures. Conversely, anabolic treatments for osteoporosis enhance the work of the osteoblast by altering osteoblast metabolism. Emerging evidence supports glycolysis as the major metabolic pathway to meet ATP demand during osteoblast differentiation. Glut1 and Glut3 are the principal transporters of glucose in osteoblasts, although Glut4 has also been implicated. Wnt signaling induces osteoblast differentiation and activates glycolysis through mammalian target of rapamycin, whereas parathyroid hormone stimulates glycolysis through induction of insulin-like growth factor-I. Glutamine is an alternate fuel source for osteogenesis via the tricarboxylic acid cycle, and fatty acids can be metabolized to generate ATP via oxidative phosphorylation although temporal specificity has not been established. More studies with new model systems are needed to fully understand how the osteoblast utilizes fuel substrates in health and disease and how that impacts metabolic bone diseases.
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Affiliation(s)
- Wen-Chih Lee
- Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Anyonya R Guntur
- Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Fanxin Long
- Department of Orthopedic Surgery, Washington University School of Medicine, St. Louis, Missouri 63110.,Departments of Medicine and Developmental Biology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Clifford J Rosen
- Maine Medical Center Research Institute, Scarborough, Maine 04074
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97
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Meakin LB, Todd H, Delisser PJ, Galea GL, Moustafa A, Lanyon LE, Windahl SH, Price JS. Parathyroid hormone's enhancement of bones' osteogenic response to loading is affected by ageing in a dose- and time-dependent manner. Bone 2017; 98:59-67. [PMID: 28249797 PMCID: PMC5404907 DOI: 10.1016/j.bone.2017.02.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Revised: 02/18/2017] [Accepted: 02/20/2017] [Indexed: 11/29/2022]
Abstract
Decreased effectiveness of bones' adaptive response to mechanical loading contributes to age-related bone loss. In young mice, intermittent administration of parathyroid hormone (iPTH) at 20-80μg/kg/day interacts synergistically with artificially applied loading to increase bone mass. Here we report investigations on the effect of different doses and duration of iPTH treatment on mice whose osteogenic response to artificial loading is impaired by age. One group of aged, 19-month-old female C57BL/6 mice was given 0, 25, 50 or 100μg/kg/day iPTH for 4weeks. Histological and μCT analysis of their tibiae revealed potent iPTH dose-related increases in periosteally-enclosed area, cortical area and porosity with decreased cortical thickness. There was practically no effect on trabecular bone. Another group was given a submaximal dose of 50μg/kg/day iPTH or vehicle for 2 or 6weeks with loading of their right tibia three times per week for the final 2weeks. In the trabecular bone of these mice the loading-related increase in BV/TV was abrogated by iPTH primarily by reduction of the increase in trabecular number. In their cortical bone, iPTH treatment time-dependently increased cortical porosity. Loading partially reduced this effect. The osteogenic effects of iPTH and loading on periosteally-enclosed area and cortical area were additive but not synergistic. Thus in aged, unlike young mice, iPTH and loading appear to have separate effects. iPTH alone causes a marked increase in cortical porosity which loading reduces. Both iPTH and loading have positive effects on cortical periosteal bone formation but these are additive rather than synergistic.
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Affiliation(s)
- Lee B Meakin
- School of Veterinary Sciences, University of Bristol, Bristol, UK.
| | - Henry Todd
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Peter J Delisser
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Gabriel L Galea
- School of Veterinary Sciences, University of Bristol, Bristol, UK; Newlife Birth Defects Research Centre, UCL Great Ormond Street Institute of Child Health, UCL, London, UK
| | - Alaa Moustafa
- School of Veterinary Sciences, University of Bristol, Bristol, UK; Department of Surgery, Faculty of Veterinary Medicine, Kafr El-Sheikh University, Kafr El-Sheikh, Egypt
| | - Lance E Lanyon
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Sara H Windahl
- School of Veterinary Sciences, University of Bristol, Bristol, UK; Centre for Bone and Arthritis Research, Institute of Medicine, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden
| | - Joanna S Price
- School of Veterinary Sciences, University of Bristol, Bristol, UK
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98
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Karner CM, Long F. Wnt signaling and cellular metabolism in osteoblasts. Cell Mol Life Sci 2017; 74:1649-1657. [PMID: 27888287 PMCID: PMC5380548 DOI: 10.1007/s00018-016-2425-5] [Citation(s) in RCA: 200] [Impact Index Per Article: 28.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Revised: 11/15/2016] [Accepted: 11/17/2016] [Indexed: 12/20/2022]
Abstract
The adult human skeleton is a multifunctional organ undergoing continuous remodeling. Homeostasis of bone mass in a healthy adult requires an exquisite balance between bone resorption by osteoclasts and bone formation by osteoblasts; disturbance of such balance is the root cause for various bone disorders including osteoporosis. To develop effective and safe therapeutics to modulate bone formation, it is essential to elucidate the molecular mechanisms governing osteoblast differentiation and activity. Due to their specialized function in collagen synthesis and secretion, osteoblasts are expected to consume large amounts of nutrients. However, studies of bioenergetics and building blocks in osteoblasts have been lagging behind those of growth factors and transcription factors. Genetic studies in both humans and mice over the past 15 years have established Wnt signaling as a critical mechanism for stimulating osteoblast differentiation and activity. Importantly, recent studies have uncovered that Wnt signaling directly reprograms cellular metabolism by stimulating aerobic glycolysis, glutamine catabolism as well as fatty acid oxidation in osteoblast-lineage cells. Such findings therefore reveal an important regulatory axis between bone anabolic signals and cellular bioenergetics. A comprehensive understanding of osteoblast metabolism and its regulation is likely to reveal molecular targets for novel bone therapies.
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Affiliation(s)
- Courtney M Karner
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 63131, USA
- Department of Orthopaedic Surgery, Duke Orthopaedic, Cellular, Developmental and Genome Laboratories, Duke University School of Medicine, Durham, NC, 27710, USA
- Department of Cell Biology, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Fanxin Long
- Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, MO, 63131, USA.
- Department of Developmental Biology, Washington University School of Medicine, St. Louis, MO, 63131, USA.
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99
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Galea GL, Meakin LB, Harris MA, Delisser PJ, Lanyon LE, Harris SE, Price JS. Old age and the associated impairment of bones' adaptation to loading are associated with transcriptomic changes in cellular metabolism, cell-matrix interactions and the cell cycle. Gene 2017; 599:36-52. [PMID: 27840164 PMCID: PMC5139832 DOI: 10.1016/j.gene.2016.11.006] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Accepted: 11/06/2016] [Indexed: 02/08/2023]
Abstract
In old animals, bone's ability to adapt its mass and architecture to functional load-bearing requirements is diminished, resulting in bone loss characteristic of osteoporosis. Here we investigate transcriptomic changes associated with this impaired adaptive response. Young adult (19-week-old) and aged (19-month-old) female mice were subjected to unilateral axial tibial loading and their cortical shells harvested for microarray analysis between 1h and 24h following loading (36 mice per age group, 6 mice per loading group at 6 time points). In non-loaded aged bones, down-regulated genes are enriched for MAPK, Wnt and cell cycle components, including E2F1. E2F1 is the transcription factor most closely associated with genes down-regulated by ageing and is down-regulated at the protein level in osteocytes. Genes up-regulated in aged bone are enriched for carbohydrate metabolism, TNFα and TGFβ superfamily components. Loading stimulates rapid and sustained transcriptional responses in both age groups. However, genes related to proliferation are predominantly up-regulated in the young and down-regulated in the aged following loading, whereas those implicated in bioenergetics are down-regulated in the young and up-regulated in the aged. Networks of inter-related transcription factors regulated by E2F1 are loading-responsive in both age groups. Loading regulates genes involved in similar signalling cascades in both age groups, but these responses are more sustained in the young than aged. From this we conclude that cells in aged bone retain the capability to sense and transduce loading-related stimuli, but their ability to translate acute responses into functionally relevant outcomes is diminished.
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Affiliation(s)
- Gabriel L Galea
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Lee B Meakin
- School of Veterinary Sciences, University of Bristol, Bristol, UK.
| | - Marie A Harris
- Department of Periodontics & Cellular and Structural Biology, University of Texas Health Science Centre, San Antonio, USA
| | - Peter J Delisser
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Lance E Lanyon
- School of Veterinary Sciences, University of Bristol, Bristol, UK
| | - Stephen E Harris
- Department of Periodontics & Cellular and Structural Biology, University of Texas Health Science Centre, San Antonio, USA
| | - Joanna S Price
- School of Veterinary Sciences, University of Bristol, Bristol, UK
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100
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Karner CM, Esen E, Chen J, Hsu FF, Turk J, Long F. Wnt Protein Signaling Reduces Nuclear Acetyl-CoA Levels to Suppress Gene Expression during Osteoblast Differentiation. J Biol Chem 2016; 291:13028-39. [PMID: 27129247 PMCID: PMC4933220 DOI: 10.1074/jbc.m115.708578] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Revised: 04/01/2016] [Indexed: 02/04/2023] Open
Abstract
Developmental signals in metazoans play critical roles in inducing cell differentiation from multipotent progenitors. The existing paradigm posits that the signals operate directly through their downstream transcription factors to activate expression of cell type-specific genes, which are the hallmark of cell identity. We have investigated the mechanism through which Wnt signaling induces osteoblast differentiation in an osteoblast-adipocyte bipotent progenitor cell line. Unexpectedly, Wnt3a acutely suppresses the expression of a large number of genes while inducing osteoblast differentiation. The suppressed genes include Pparg and Cebpa, which encode adipocyte-specifying transcription factors and suppression of which is sufficient to induce osteoblast differentiation. The large scale gene suppression induced by Wnt3a corresponds to a global decrease in histone acetylation, an epigenetic modification that is associated with gene activation. Mechanistically, Wnt3a does not alter histone acetyltransferase or deacetylase activities but, rather, decreases the level of acetyl-CoA in the nucleus. The Wnt-induced decrease in histone acetylation is independent of β-catenin signaling but, rather, correlates with suppression of glucose metabolism in the tricarboxylic acid cycle. Functionally, preventing histone deacetylation by increasing nucleocytoplasmic acetyl-CoA levels impairs Wnt3a-induced osteoblast differentiation. Thus, Wnt signaling induces osteoblast differentiation in part through histone deacetylation and epigenetic suppression of an alternative cell fate.
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Affiliation(s)
| | - Emel Esen
- From the Department of Orthopaedic Surgery, Division of Biology and Biomedical Sciences
| | | | - Fong-Fu Hsu
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63131
| | - John Turk
- Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63131
| | - Fanxin Long
- From the Department of Orthopaedic Surgery, Division of Biology and Biomedical Sciences, Department of Medicine, Washington University School of Medicine, Saint Louis, Missouri 63131 Department of Developmental Biology, and
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