1
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Sarver DC, Garcia-Diaz J, Saqib M, Riddle RC, Wong GW. Tmem263 deletion disrupts the GH/IGF-1 axis and causes dwarfism and impairs skeletal acquisition. eLife 2024; 12:RP90949. [PMID: 38241182 PMCID: PMC10945605 DOI: 10.7554/elife.90949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2024] Open
Abstract
Genome-wide association studies (GWAS) have identified a large number of candidate genes believed to affect longitudinal bone growth and bone mass. One of these candidate genes, TMEM263, encodes a poorly characterized plasma membrane protein. Single nucleotide polymorphisms in TMEM263 are associated with bone mineral density in humans and mutations are associated with dwarfism in chicken and severe skeletal dysplasia in at least one human fetus. Whether this genotype-phenotype relationship is causal, however, remains unclear. Here, we determine whether and how TMEM263 is required for postnatal growth. Deletion of the Tmem263 gene in mice causes severe postnatal growth failure, proportional dwarfism, and impaired skeletal acquisition. Mice lacking Tmem263 show no differences in body weight within the first 2 weeks of postnatal life. However, by P21 there is a dramatic growth deficit due to a disrupted growth hormone (GH)/insulin-like growth factor 1 (IGF-1) axis, which is critical for longitudinal bone growth. Tmem263-null mice have low circulating IGF-1 levels and pronounced reductions in bone mass and growth plate length. The low serum IGF-1 in Tmem263-null mice is associated with reduced hepatic GH receptor (GHR) expression and GH-induced JAK2/STAT5 signaling. A deficit in GH signaling dramatically alters GH-regulated genes and feminizes the liver transcriptome of Tmem263-null male mice, with their expression profile resembling wild-type female, hypophysectomized male, and Stat5b-null male mice. Collectively, our data validates the causal role for Tmem263 in regulating postnatal growth and raises the possibility that rare mutations or variants of TMEM263 may potentially cause GH insensitivity and impair linear growth.
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Affiliation(s)
- Dylan C Sarver
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Jean Garcia-Diaz
- Department of Orthopaedic Surgery, Johns Hopkins University School of MedicineBaltimoreUnited States
- Department of Orthopaedics, University of Maryland School of MedicineBaltimoreUnited States
- Cell and Molecular Medicine graduate program, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Muzna Saqib
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of MedicineBaltimoreUnited States
- Department of Orthopaedics, University of Maryland School of MedicineBaltimoreUnited States
- Research and Development Service, Baltimore Veterans Administration Medical CenterBaltimoreUnited States
| | - G William Wong
- Department of Physiology, Johns Hopkins University School of MedicineBaltimoreUnited States
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2
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Gao CW, Lin W, Riddle RC, Kushwaha P, Boukas L, Björnsson HT, Hansen KD, Fahrner JA. A mouse model of Weaver syndrome displays overgrowth and excess osteogenesis reversible with KDM6A/6B inhibition. JCI Insight 2024; 9:e173392. [PMID: 38015625 PMCID: PMC10906465 DOI: 10.1172/jci.insight.173392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 11/14/2023] [Indexed: 11/30/2023] Open
Abstract
Weaver syndrome is a Mendelian disorder of the epigenetic machinery (MDEM) caused by germline pathogenic variants in EZH2, which encodes the predominant H3K27 methyltransferase and key enzymatic component of Polycomb repressive complex 2 (PRC2). Weaver syndrome is characterized by striking overgrowth and advanced bone age, intellectual disability, and distinctive facies. We generated a mouse model for the most common Weaver syndrome missense variant, EZH2 p.R684C. Ezh2R684C/R684C mouse embryonic fibroblasts (MEFs) showed global depletion of H3K27me3. Ezh2R684C/+ mice had abnormal bone parameters, indicative of skeletal overgrowth, and Ezh2R684C/+ osteoblasts showed increased osteogenic activity. RNA-Seq comparing osteoblasts differentiated from Ezh2R684C/+, and Ezh2+/+ BM-mesenchymal stem cells (BM-MSCs) indicated collective dysregulation of the BMP pathway and osteoblast differentiation. Inhibition of the opposing H3K27 demethylases KDM6A and KDM6B substantially reversed the excessive osteogenesis in Ezh2R684C/+ cells both at the transcriptional and phenotypic levels. This supports both the ideas that writers and erasers of histone marks exist in a fine balance to maintain epigenome state and that epigenetic modulating agents have therapeutic potential for the treatment of MDEMs.
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Affiliation(s)
- Christine W. Gao
- Department of Genetic Medicine
- Department of Molecular Biology and Genetics, and
| | | | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
| | - Priyanka Kushwaha
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Leandros Boukas
- Department of Genetic Medicine
- Department of Biostatistics, Johns Hopkins University School of Public Health, Baltimore, Maryland, USA
| | - Hans T. Björnsson
- Department of Genetic Medicine
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Faculty of Medicine, University of Iceland, Reykjavík, Iceland
- Landspítali University Hospital, Reykjavík, Iceland
| | - Kasper D. Hansen
- Department of Genetic Medicine
- Department of Biostatistics, Johns Hopkins University School of Public Health, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jill A. Fahrner
- Department of Genetic Medicine
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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3
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Affiliation(s)
- Ryan C Riddle
- Division of Musculoskeletal Science, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA.
- Research and Development Service, Baltimore VA Medical Center, Baltimore, MD, USA.
| | - Gillian M Choquette
- Division of Musculoskeletal Science, Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, USA
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4
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Sarver DC, Garcia-Diaz J, Saqib M, Riddle RC, Wong GW. Tmem263 deletion disrupts the GH/IGF-1 axis and causes dwarfism and impairs skeletal acquisition. bioRxiv 2023:2023.08.02.551694. [PMID: 37577461 PMCID: PMC10418210 DOI: 10.1101/2023.08.02.551694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/15/2023]
Abstract
Genome-wide association studies (GWAS) have identified a large number of candidate genes believed to affect longitudinal bone growth and bone mass. One of these candidate genes, TMEM263, encodes a poorly characterized plasma membrane protein. Single nucleotide polymorphisms in TMEM263 are associated with bone mineral density in humans and mutations are associated with dwarfism in chicken and severe skeletal dysplasia in at least one human fetus. Whether this genotype-phenotype relationship is causal, however, remains unclear. Here, we determine whether and how TMEM263 is required for postnatal growth. Deletion of the Tmem263 gene in mice causes severe postnatal growth failure, proportional dwarfism, and impaired skeletal acquisition. Mice lacking Tmem263 show no differences in body weight within the first two weeks of postnatal life. However, by P21 there is a dramatic growth deficit due to a disrupted GH/IGF-1 axis, which is critical for longitudinal bone growth. Tmem263-null mice have low circulating IGF-1 levels and pronounced reductions in bone mass and growth plate length. The low serum IGF-1 in Tmem263-null mice is associated with reduced hepatic GH receptor (GHR) expression and GH-induced JAK2/STAT5 signaling. A deficit in GH signaling dramatically alters GH-regulated genes and feminizes the liver transcriptome of Tmem263-null male mice, with their expression profile resembling a wild-type female, hypophysectomized male, and Stat5b-null male mice. Collectively, our data validates the causal role for Tmem263 in regulating postnatal growth and raises the possibility that rare mutations or variants of TMEM263 may potentially cause GH insensitivity and impair linear growth.
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Affiliation(s)
- Dylan C Sarver
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jean Garcia-Diaz
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Cell and Molecular Medicine graduate program, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Muzna Saqib
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
| | - G William Wong
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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5
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Kim SP, Seward AH, Garcia-Diaz J, Alekos N, Gould NR, Aja S, Stains JP, Wolfgang MJ, Riddle RC. Peroxisome proliferator activated receptor-γ in osteoblasts controls bone formation and fat mass by regulating sclerostin expression. iScience 2023; 26:106999. [PMID: 37534168 PMCID: PMC10391670 DOI: 10.1016/j.isci.2023.106999] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 05/01/2023] [Accepted: 05/25/2023] [Indexed: 08/04/2023] Open
Abstract
The nuclear receptor peroxisome proliferator activated receptor-γ (PPARγ) is a key contributor to metabolic function via its adipogenic and insulin-sensitizing functions, but it has negative effects on skeletal homeostasis. Here, we questioned whether the skeletal and metabolic actions of PPARγ are linked. Ablating Pparg expression in osteoblasts and osteocytes produced a high bone mass phenotype, secondary to increased osteoblast activity, and a reduction in subcutaneous fat mass because of reduced fatty acid synthesis and increased fat oxidation. The skeletal and metabolic phenotypes in Pparg mutants proceed from the regulation of sclerostin production by PPARγ. Mutants exhibited reductions in skeletal Sost expression and serum sclerostin levels while increasing production normalized both phenotypes. Importantly, disrupting the production of sclerostin synergized with the insulin-sensitizing actions of a PPARγ agonist while preventing bone loss. These data suggest that modulating sclerostin action may prevent bone loss associated with anti-diabetic therapies and augment their metabolic actions.
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Affiliation(s)
- Soohyun P. Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Avery H. Seward
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jean Garcia-Diaz
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nathalie Alekos
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Nicole R. Gould
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Susan Aja
- Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Joseph P. Stains
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | - Michael J. Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201, USA
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, MD 21201, USA
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6
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Gao CW, Lin W, Riddle RC, Kushwaha P, Boukas L, Björnsson HT, Hansen KD, Fahrner JA. Novel mouse model of Weaver syndrome displays overgrowth and excess osteogenesis reversible with KDM6A/6B inhibition. bioRxiv 2023:2023.06.23.546270. [PMID: 37425751 PMCID: PMC10327066 DOI: 10.1101/2023.06.23.546270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Weaver syndrome is a Mendelian disorder of the epigenetic machinery (MDEM) caused by germline pathogenic variants in EZH2, which encodes the predominant H3K27 methyltransferase and key enzymatic component of Polycomb repressive complex 2 (PRC2). Weaver syndrome is characterized by striking overgrowth and advanced bone age, intellectual disability, and distinctive facies. We generated a mouse model for the most common Weaver syndrome missense variant, EZH2 p.R684C. Ezh2R684C/R684C mouse embryonic fibroblasts (MEFs) showed global depletion of H3K27me3. Ezh2R684C/+ mice had abnormal bone parameters indicative of skeletal overgrowth, and Ezh2R684C/+ osteoblasts showed increased osteogenic activity. RNA-seq comparing osteoblasts differentiated from Ezh2R684C/+ and Ezh2+/+ bone marrow mesenchymal stem cells (BM-MSCs) indicated collective dysregulation of the BMP pathway and osteoblast differentiation. Inhibition of the opposing H3K27 demethylases Kdm6a/6b substantially reversed the excessive osteogenesis in Ezh2R684C/+ cells both at the transcriptional and phenotypic levels. This supports both the ideas that writers and erasers of histone marks exist in a fine balance to maintain epigenome state, and that epigenetic modulating agents have therapeutic potential for the treatment of MDEMs.
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Affiliation(s)
- Christine W Gao
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Molecular Biology and Genetics, Johns Hopkins University School of Medicine, Baltimore, MD
| | - WanYing Lin
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, MD
| | - Priyanka Kushwaha
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Leandros Boukas
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Biostatistics, Johns Hopkins University School of Public Health, Baltimore, MD
| | - Hans T Björnsson
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
- Faculty of Medicine, University of Iceland, Reykjavík, Iceland
- Landspítali University Hospital, Reykjavík, Iceland
| | - Kasper D Hansen
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Biostatistics, Johns Hopkins University School of Public Health, Baltimore, MD
| | - Jill A Fahrner
- Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
- Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, MD
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7
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van der Eerden BCJ, Riddle RC, Stegen S, Tencerova M. Editorial: Energy metabolism within the skeleton. Front Physiol 2023; 14:1205435. [PMID: 37284545 PMCID: PMC10240058 DOI: 10.3389/fphys.2023.1205435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 05/16/2023] [Indexed: 06/08/2023] Open
Affiliation(s)
- Bram C. J. van der Eerden
- Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, Netherlands
| | - Ryan C. Riddle
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
- Research and Development Service, Baltimore VA Medical Center, Baltimore, MD, United States
| | - Steve Stegen
- Department of Chronic Diseases and Metabolism, Clinical and Experimental Endocrinology, KU Leuven, Leuven, Belgium
| | - Michaela Tencerova
- Molecular Physiology of Bone, Institute of Physiology of the Czech Academy of Sciences, Prague, Czechia
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8
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Alekos NS, Kushwaha P, Kim SP, Li Z, Abood A, Dirckx N, Aja S, Kodama J, Garcia-Diaz JG, Otsuru S, Rendina-Ruedy E, Wolfgang MJ, Riddle RC. Mitochondrial β-oxidation of adipose-derived fatty acids by osteoblasts fuels parathyroid hormone-induced bone formation. JCI Insight 2023; 8:165604. [PMID: 36729662 PMCID: PMC10070112 DOI: 10.1172/jci.insight.165604] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Accepted: 02/01/2023] [Indexed: 02/03/2023] Open
Abstract
The energetic costs of bone formation require osteoblasts to coordinate their activities with tissues, like adipose, that can supply energy-dense macronutrients. In the case of intermittent parathyroid hormone (PTH) treatment, a strategy used to reduce fracture risk, bone formation is preceded by a change in systemic lipid homeostasis. To investigate the requirement for fatty acid oxidation by osteoblasts during PTH-induced bone formation, we subjected mice with osteoblast-specific deficiency of mitochondrial long-chain β-oxidation as well as mice with adipocyte-specific deficiency for the PTH receptor or adipose triglyceride lipase to an anabolic treatment regimen. PTH increased the release of fatty acids from adipocytes and β-oxidation by osteoblasts, while the genetic mouse models were resistant to the hormone's anabolic effect. Collectively, these data suggest that PTH's anabolic actions require coordinated signaling between bone and adipose, wherein a lipolytic response liberates fatty acids that are oxidized by osteoblasts to fuel bone formation.
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Affiliation(s)
- Nathalie S Alekos
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Priyanka Kushwaha
- Division of Rheumatology, Inflammation, and Immunity, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Soohyun P Kim
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zhu Li
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Abdullah Abood
- Center for Public Health Genomics, School of Medicine, University of Virginia, Charlottesville, Virginia, USA
| | - Naomi Dirckx
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Susan Aja
- Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Joe Kodama
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Jean G Garcia-Diaz
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Graduate Program in Cellular and Molecular Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Satoru Otsuru
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Elizabeth Rendina-Ruedy
- Department of Medicine and Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Michael J Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ryan C Riddle
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
- Research & Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
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9
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Riddle RC. Endocrine Functions of Sclerostin. Curr Opin Endocr Metab Res 2023; 28:10.1016/j.coemr.2022.100433. [PMID: 36713826 PMCID: PMC9881182 DOI: 10.1016/j.coemr.2022.100433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Sclerostin, the product of the SOST gene has primarily been studied for its profound impact on bone mass. By interacting with LRP5 and LRP6, the glycoprotein suppresses the propagation of Wnt signals to β-catenin and thereby suppresses new bone formation. In this review, we discuss emerging data which suggest that sclerostin also acts outside the skeleton to influence metabolism. In humans, serum sclerostin levels are associated with body mass index and indices of metabolic function. Likewise, genetic mouse models of Sost gene deficiency indicate sclerostin influences adipocyte development and insulin signaling. These data raise the possibility that sclerostin neutralization may be effective at treating two epidemic conditions: osteoporosis and obesity.
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Affiliation(s)
- Ryan C. Riddle
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA.,Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA.,Address Correspondence to: Ryan C. Riddle, Ph.D., Department of Orthopaedics, University of Maryland School of Medicine, 660 W. Redwood Street, Room 592, Baltimore, MD 21201, USA, , Ph: 410-706-0422
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10
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Dirckx N, Zhang Q, Chu EY, Tower RJ, Li Z, Guo S, Yuan S, Khare PA, Zhang C, Verardo A, Alejandro LO, Park A, Faugere MC, Helfand SL, Somerman MJ, Riddle RC, de Cabo R, Le A, Schmidt-Rohr K, Clemens TL. A specialized metabolic pathway partitions citrate in hydroxyapatite to impact mineralization of bones and teeth. Proc Natl Acad Sci U S A 2022; 119:e2212178119. [PMID: 36322718 PMCID: PMC9659386 DOI: 10.1073/pnas.2212178119] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/17/2022] [Indexed: 11/06/2022] Open
Abstract
Citrate is a critical metabolic substrate and key regulator of energy metabolism in mammalian cells. It has been known for decades that the skeleton contains most (>85%) of the body's citrate, but the question of why and how this metabolite should be partitioned in bone has received singularly little attention. Here, we show that osteoblasts use a specialized metabolic pathway to regulate uptake, endogenous production, and the deposition of citrate into bone. Osteoblasts express high levels of the membranous Na+-dependent citrate transporter solute carrier family 13 member 5 (Slc13a5) gene. Inhibition or genetic disruption of Slc13a5 reduced osteogenic citrate uptake and disrupted mineral nodule formation. Bones from mice lacking Slc13a5 globally, or selectively in osteoblasts, showed equivalent reductions in cortical thickness, with similarly compromised mechanical strength. Surprisingly, citrate content in mineral from Slc13a5-/- osteoblasts was increased fourfold relative to controls, suggesting the engagement of compensatory mechanisms to augment endogenous citrate production. Indeed, through the coordinated functioning of the apical membrane citrate transporter SLC13A5 and a mitochondrial zinc transporter protein (ZIP1; encoded by Slc39a1), a mediator of citrate efflux from the tricarboxylic acid cycle, SLC13A5 mediates citrate entry from blood and its activity exerts homeostatic control of cytoplasmic citrate. Intriguingly, Slc13a5-deficient mice also exhibited defective tooth enamel and dentin formation, a clinical feature, which we show is recapitulated in primary teeth from children with SLC13A5 mutations. Together, our results reveal the components of an osteoblast metabolic pathway, which affects bone strength by regulating citrate deposition into mineral hydroxyapatite.
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Affiliation(s)
- Naomi Dirckx
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Qian Zhang
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Nutrition and Health, China Agricultural University, Beijing 100193, China
| | - Emily Y. Chu
- Department of General Dentistry, Operative Division, University of Maryland School of Dentistry, Baltimore, MD 21201
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892
| | - Robert J. Tower
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390
| | - Zhu Li
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
| | - Shenghao Guo
- Department of Biomedical Engineering, Johns Hopkins University Whiting School of Engineering, Baltimore, MD 21218
| | - Shichen Yuan
- Department of Chemistry, Brandeis University, Waltham, MA 02453
| | - Pratik A. Khare
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
| | - Cissy Zhang
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21287
| | - Angela Verardo
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Lucy O. Alejandro
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892
| | - Angelina Park
- Department of General Dentistry, Operative Division, University of Maryland School of Dentistry, Baltimore, MD 21201
| | | | - Stephen L. Helfand
- Department of Molecular Biology, Cell Biology and Biochemistry, Brown University, Providence, RI 02906
| | - Martha J. Somerman
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, MD 20892
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
- Research and Development Service, The Baltimore Veterans Administration Medical Center, Baltimore, MD 21201
| | - Rafael de Cabo
- Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD 21224
| | - Anne Le
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, MD 21287
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, MD 21231
| | | | - Thomas L. Clemens
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD 21201
- Research and Development Service, The Baltimore Veterans Administration Medical Center, Baltimore, MD 21201
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11
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Lin BL, Shin JY, Jeffreys WP, Wang N, Lukban CA, Moorer MC, Velarde E, Hanselman OA, Kwon S, Kannan S, Riddle RC, Ward CW, Pullen SS, Filareto A, Kass DA. Pharmacological TRPC6 inhibition improves survival and muscle function in mice with Duchenne muscular dystrophy. JCI Insight 2022; 7:e158906. [PMID: 36099033 PMCID: PMC9675567 DOI: 10.1172/jci.insight.158906] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 08/26/2022] [Indexed: 11/17/2022] Open
Abstract
Gene mutations causing loss of dystrophin result in the severe muscle disease known as Duchenne muscular dystrophy (DMD). Despite efforts at genetic repair, DMD therapy remains largely palliative. Loss of dystrophin destabilizes the sarcolemmal membrane, inducing mechanosensitive cation channels to increase calcium entry and promote cell damage and, eventually, muscle dysfunction. One putative channel is transient receptor potential canonical 6 (TRPC6); we have shown that TRPC6 contributed to abnormal force and calcium stress-responses in cardiomyocytes from mice lacking dystrophin that were haplodeficient for utrophin (mdx/utrn+/- [HET] mice). Here, we show in both the HET mouse and the far more severe homozygous mdx/utrn-/- mouse that TRPC6 gene deletion or its selective pharmacologic inhibition (by BI 749327) prolonged survival 2- to 3-fold, improving skeletal and cardiac muscle and bone defects. Gene pathways reduced by BI 749327 treatment most prominently regulated fat metabolism and TGF-β1 signaling. These results support the testing of TRPC6 inhibitors in human trials for other diseases as a novel DMD therapy.
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Affiliation(s)
| | | | | | | | | | | | - Esteban Velarde
- Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University, Baltimore, Maryland, USA
| | | | | | | | | | | | | | - Antonio Filareto
- Research Beyond Borders, Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut, USA
| | - David A. Kass
- Department of Cardiology
- Department of Pharmacology and Molecular Sciences, Johns Hopkins University, Baltimore, Maryland, USA
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12
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Kushwaha P, Alekos NS, Kim SP, Li Z, Wolfgang MJ, Riddle RC. Mitochondrial fatty acid β-oxidation is important for normal osteoclast formation in growing female mice. Front Physiol 2022; 13:997358. [PMID: 36187756 PMCID: PMC9515402 DOI: 10.3389/fphys.2022.997358] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 08/22/2022] [Indexed: 12/03/2022] Open
Abstract
Skeletal remodeling is an energy demanding process that is linked to nutrient availability and the levels of metabolic hormones. While recent studies have examined the metabolic requirements of bone formation by osteoblasts, much less is known about the energetic requirements of bone resorption by osteoclasts. The abundance of mitochondria in mature osteoclasts suggests that the production of an acidified micro-environment conducive to the ionization of hydroxyapatite, secretion of matrix-degrading enzymes, and motility during resorption requires significant energetic capacity. To investigate the contribution of mitochondrial long chain fatty acid β-oxidation to osteoclast development, we disrupted the expression of carnitine palmitoyltransferase-2 (Cpt2) in myeloid-lineage cells. Fatty acid oxidation increases dramatically in bone marrow cultures stimulated with RANKL and M-CSF and microCT analysis revealed that the genetic inhibition of long chain fatty acid oxidation in osteoclasts significantly increases trabecular bone volume in female mice secondary to reduced osteoclast numbers. In line with these data, osteoclast precursors isolated from Cpt2 mutants exhibit reduced capacity to form large-multinucleated osteoclasts, which was not rescued by exogenous glucose or pyruvate, and signs of an energetic stress response. Together, our data demonstrate that mitochondrial long chain fatty acid oxidation by the osteoclast is required for normal bone resorption as its inhibition produces an intrinsic defect in osteoclast formation.
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Affiliation(s)
- Priyanka Kushwaha
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Nathalie S. Alekos
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Soohyun P. Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Zhu Li
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States
| | - Michael J. Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States,Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, MD, United States,Baltimore Veterans Administration Medical Center, Baltimore, MD, United States,*Correspondence: Ryan C. Riddle,
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13
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Kim SP, Li Z, Riddle RC. Evaluation of Fatty Acid Oxidation in Cultured Bone Cells. J Vis Exp 2022. [DOI: 10.3791/63638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
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14
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Fulzele K, Riddle RC, DiGirolamo DJ, Cao X, Wan C, Chen D, Faugere MC, Aja S, Hussain MA, Brüning JC, Clemens TL. Insulin Receptor Signaling in Osteoblasts Regulates Postnatal Bone Acquisition and Body Composition. Cell 2022; 185:746. [PMID: 35180388 DOI: 10.1016/j.cell.2022.01.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Bhargava A, Monteagudo B, Kushwaha P, Senarathna J, Ren Y, Riddle RC, Aggarwal M, Pathak AP. VascuViz: a multimodality and multiscale imaging and visualization pipeline for vascular systems biology. Nat Methods 2022; 19:242-254. [PMID: 35145319 PMCID: PMC8842955 DOI: 10.1038/s41592-021-01363-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Accepted: 11/29/2021] [Indexed: 12/19/2022]
Abstract
Despite advances in imaging, image-based vascular systems biology has remained challenging because blood vessel data are often available only from a single modality or at a given spatial scale, and cross-modality data are difficult to integrate. Therefore, there is an exigent need for a multimodality pipeline that enables ex vivo vascular imaging with magnetic resonance imaging, computed tomography and optical microscopy of the same sample, while permitting imaging with complementary contrast mechanisms from the whole-organ to endothelial cell spatial scales. To achieve this, we developed 'VascuViz'-an easy-to-use method for simultaneous three-dimensional imaging and visualization of the vascular microenvironment using magnetic resonance imaging, computed tomography and optical microscopy in the same intact, unsectioned tissue. The VascuViz workflow permits multimodal imaging with a single labeling step using commercial reagents and is compatible with diverse tissue types and protocols. VascuViz's interdisciplinary utility in conjunction with new data visualization approaches opens up new vistas in image-based vascular systems biology.
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Affiliation(s)
- Akanksha Bhargava
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Benjamin Monteagudo
- Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Priyanka Kushwaha
- Departments of Orthopedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Janaka Senarathna
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yunke Ren
- Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ryan C Riddle
- Departments of Orthopedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - Manisha Aggarwal
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Arvind P Pathak
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Biomedical Engineering, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Electrical Engineering, The Johns Hopkins University, Baltimore, MD, USA.
- The Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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16
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Farris AL, Lambrechts D, Zhou Y, Zhang NY, Sarkar N, Moorer MC, Rindone AN, Nyberg EL, Perdomo-Pantoja A, Burris SJ, Free K, Witham TF, Riddle RC, Grayson WL. 3D-printed oxygen-releasing scaffolds improve bone regeneration in mice. Biomaterials 2022; 280:121318. [PMID: 34922272 PMCID: PMC8918039 DOI: 10.1016/j.biomaterials.2021.121318] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 11/06/2021] [Accepted: 12/08/2021] [Indexed: 01/03/2023]
Abstract
Low oxygen (O2) diffusion into large tissue engineered scaffolds hinders the therapeutic efficacy of transplanted cells. To overcome this, we previously studied hollow, hyperbarically-loaded microtanks (μtanks) to serve as O2 reservoirs. To adapt these for bone regeneration, we fabricated biodegradable μtanks from polyvinyl alcohol and poly (lactic-co-glycolic acid) and embedded them to form 3D-printed, porous poly-ε-caprolactone (PCL)-μtank scaffolds. PCL-μtank scaffolds were loaded with pure O2 at 300-500 psi. When placed at atmospheric pressures, the scaffolds released O2 over a period of up to 8 h. We confirmed the inhibitory effects of hypoxia on the osteogenic differentiation of human adipose-derived stem cells (hASCs and we validated that μtank-mediated transient hyperoxia had no toxic impacts on hASCs, possibly due to upregulation of endogenous antioxidant regulator genes. We assessed bone regeneration in vivo by implanting O2-loaded, hASC-seeded, PCL-μtank scaffolds into murine calvarial defects (4 mm diameters × 0.6 mm height) and subcutaneously (4 mm diameter × 8 mm height). In both cases we observed increased deposition of extracellular matrix in the O2 delivery group along with greater osteopontin coverages and higher mineral deposition. This study provides evidence that even short-term O2 delivery from PCL-μtank scaffolds may enhance hASC-mediated bone tissue regeneration.
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Affiliation(s)
- Ashley L. Farris
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Dennis Lambrechts
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Yuxiao Zhou
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nicholas Y. Zhang
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Naboneeta Sarkar
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Megan C. Moorer
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD,Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - Alexandra N. Rindone
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Ethan L. Nyberg
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | | | - S. J. Burris
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Kendall Free
- Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Timothy F. Witham
- Department of Neurosurgery, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Ryan C. Riddle
- Department of Orthopedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD,Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - Warren L. Grayson
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Translational Tissue Engineering Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA,Department of Materials Science and Engineering, Johns Hopkins University, Baltimore, MD, USA,Department of Chemical & Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA,Institute for NanoBioTechnology, Johns Hopkins University, Baltimore, MD,Corresponding author:
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17
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Riddle RC. Cellular and tissue crosstalk in musculoskeletal development. Semin Cell Dev Biol 2021; 123:1-3. [PMID: 34764024 DOI: 10.1016/j.semcdb.2021.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA; Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA.
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18
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Kim SP, Da H, Wang L, Taketo MM, Wan M, Riddle RC. Bone-derived sclerostin and Wnt/β-catenin signaling regulate PDGFRα + adipoprogenitor cell differentiation. FASEB J 2021; 35:e21957. [PMID: 34606641 PMCID: PMC8496915 DOI: 10.1096/fj.202100691r] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2021] [Revised: 09/03/2021] [Accepted: 09/13/2021] [Indexed: 12/13/2022]
Abstract
The Wnt signaling antagonist, sclerostin, is a potent suppressor of bone acquisition that also mediates endocrine communication between bone and adipose. As a result, Sost-/- mice exhibit dramatic increases in bone formation but marked decreases in visceral and subcutaneous adipose that are secondary to alterations in lipid synthesis and utilization. While interrogating the mechanism by which sclerostin influences adipocyte metabolism, we observed paradoxical increases in the adipogenic potential and numbers of CD45- :Sca1+ :PDGFRα+ adipoprogenitors in the stromal vascular compartment of fat pads isolated from male Sost-/- mice. Lineage tracing studies indicated that sclerostin deficiency blocks the differentiation of PDGFRα+ adipoprogenitors to mature adipocytes in association with increased Wnt/β-catenin signaling. Importantly, osteoblast/osteocyte-specific Sost gene deletion mirrors the accumulation of PDGFRα+ adipoprogenitors, reduction in fat mass, and improved glucose metabolism evident in Sost-/- mice. These data indicate that bone-derived sclerostin regulates multiple facets of adipocyte physiology ranging from progenitor cell commitment to anabolic metabolism.
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Affiliation(s)
- Soohyun P Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hao Da
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Lei Wang
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Makoto M Taketo
- Division of Experimental Therapeutics, Graduate School of Medicine, Kyoto University, Kyoto, Japan
| | - Mei Wan
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
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19
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Kushwaha P, Khambadkone SG, Li M, Goodman EJ, Aravindan N, Riddle RC, Tamashiro KLK. Maternal High-Fat Diet Induces Long-Lasting Defects in Bone Structure in Rat Offspring Through Enhanced Osteoclastogenesis. Calcif Tissue Int 2021; 108:680-692. [PMID: 33386478 PMCID: PMC8064999 DOI: 10.1007/s00223-020-00801-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Accepted: 12/17/2020] [Indexed: 12/11/2022]
Abstract
Maternal stressors during the prenatal and perinatal periods are associated with increased susceptibility for and severity of chronic disease phenotypes in adult offspring. In this study, we used a rat model of maternal high-fat diet (HFD) exposure during pregnancy and lactation to investigate the impact on skeletal homeostasis in offspring. In the distal femur, young male and female offspring (up to 3 weeks of age) from dams fed a HFD exhibited marked increases in trabecular bone volume relative to offspring from dams fed a chow diet, but this was followed by sustained bone loss. By 15 weeks of age, male offspring of HFD fed dams exhibited a 33% reduction in trabecular bone volume fraction that histomorphometric analyses revealed was due to a nearly threefold increase in the abundance of bone-resorbing osteoclasts, while there were no differences between female control and HFD offspring by 15 weeks of age. The osteoblastic differentiation of male offspring-derived bone marrow stromal cells was not affected by maternal diet. However, osteoclastic precursors isolated from the male offspring of HFD fed dams exhibited enhanced differentiation in vitro, forming larger osteoclasts with higher expression of the fusion marker DC-STAMP. This effect appears to be mediated by a cell autonomous increase in the sensitivity of precursors to RANKL. Taken together, these results suggest that maternal stressors like HFD exposure have persistent consequences for the skeletal health of offspring that may ultimately lead to a predisposition for osteopenia/osteoporosis.
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Affiliation(s)
- Priyanka Kushwaha
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 209, Baltimore, MD, 21205, USA
| | - Seva G Khambadkone
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 618, Baltimore, MD, 21205, USA
- Cellular and Molecular Medicine Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Mengni Li
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 618, Baltimore, MD, 21205, USA
| | - Ethan J Goodman
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 618, Baltimore, MD, 21205, USA
| | - Nandini Aravindan
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 618, Baltimore, MD, 21205, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 209, Baltimore, MD, 21205, USA.
- Cellular and Molecular Medicine Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
- Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, MD, USA.
| | - Kellie L K Tamashiro
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross 618, Baltimore, MD, 21205, USA.
- Cellular and Molecular Medicine Graduate Program, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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20
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Abou DS, Fears A, Summer L, Longtine M, Benabdallah N, Riddle RC, Ulmert D, Michalski JM, Wahl RL, Chesner D, Doucet M, Zachos NC, Simons BW, Thorek DL. Improved Radium-223 Therapy with Combination Epithelial Sodium Channel Blockade. J Nucl Med 2021; 62:jnumed.121.261977. [PMID: 33837069 PMCID: PMC8612198 DOI: 10.2967/jnumed.121.261977] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/19/2021] [Accepted: 03/19/2021] [Indexed: 11/29/2022] Open
Abstract
Background: Radium-223 dichloride ([223Ra]RaCl2) is the first approved alpha particle-emitting therapy and is indicated for treatment of bone metastatic castrate resistant prostate cancer. Approximately half of the dose is absorbed into the gastrointestinal (GI) tract within minutes of administration, limiting disease-site uptake and contributing to toxicity. Here, we investigate the role of enteric ion channels and their modulation for improved therapeutic efficacy and reduced side effects. Methods: Utilizing primary human duodenal organoids (enteroids) as in vitro models of the functional GI epithelium, we found that Amiloride (ENaC blocker) and NS-1619 (K+ channel activator) presented significant effects in 223Ra membranal transport. The radioactive drug distribution was evaluated for lead combinations in vivo, and in osteosarcoma and prostate cancer models. Results: Amiloride shifted 223Ra uptake in vivo from the gut, to nearly double the uptake at sites of bone remodeling. Bone tumor growth inhibition with the combination as measured by bioluminescent and X-ray imaging was significantly greater than single agents alone, and the combination resulted in no weight loss. Conclusion: This combination of approved agents may be readily implemented as a clinical approach to improve outcomes of bone metastatic cancer patients with the benefit of ameliorated tolerability.
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Affiliation(s)
| | - Amanda Fears
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Lucy Summer
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Mark Longtine
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Nadia Benabdallah
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
- Program in Quantitative Molecular Therapeutics, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Ryan C. Riddle
- Department of Orthopaedics, Johns Hopkins University, Baltimore, Maryland
- Research and Development Service, Baltimore VA Medical Center, Baltimore, Maryland
| | - David Ulmert
- Department of Pharmacology, UCLA, Los Angeles, California
- Department of Clinical Sciences, Lund University, Lund, Sweden
| | - Jeff M. Michalski
- Department of Radiation Oncology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Richard L. Wahl
- Mallinckrodt Institute of Radiology, School of Medicine, Washington University in St. Louis, St. Louis, Missouri
| | - Denise Chesner
- Division of Gastroenterology and Hepatology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Michele Doucet
- Department of Oncology, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Nicholas C. Zachos
- Division of Gastroenterology and Hepatology, Department of Medicine, School of Medicine, Johns Hopkins University, Baltimore, Maryland
| | - Brian W. Simons
- Center for Comparative Medicine, Baylor College of Medicine, Houston, Texas; and
| | - Daniel L.J. Thorek
- Department of Biomedical Engineering, Washington University in St. Louis, St. Louis, Missouri
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21
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Youngstrom DW, Zondervan RL, Doucet NR, Acevedo PK, Sexton HE, Gardner EA, Anderson JS, Kushwaha P, Little HC, Rodriguez S, Riddle RC, Kalajzic I, Wong GW, Hankenson KD. CTRP3 Regulates Endochondral Ossification and Bone Remodeling During Fracture Healing. J Orthop Res 2020; 38:996-1006. [PMID: 31808575 PMCID: PMC7162724 DOI: 10.1002/jor.24553] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Accepted: 11/24/2019] [Indexed: 02/04/2023]
Abstract
C1q/TNF-related protein 3 (CTRP3) is a cytokine known to regulate a variety of metabolic processes. Though previously undescribed in the context of bone regeneration, high throughput gene expression experiments in mice identified CTRP3 as one of the most highly upregulated genes in fracture callus tissue. Hypothesizing a positive regulatory role for CTRP3 in bone regeneration, we phenotyped skeletal development and fracture healing in CTRP3 knockout (KO) and CTRP3 overexpressing transgenic (TG) mice relative to wild-type (WT) control animals. CTRP3 KO mice experienced delayed endochondral fracture healing, resulting in abnormal mineral distribution, the presence of periosteal marrow compartments, and a nonunion-like state. Decreased osteoclast number was also observed in CTRP3 KO mice, whereas CTRP3 TG mice underwent accelerated callus remodeling. Gene expression profiling revealed a broad impact on osteoblast/osteoclast lineage commitment and metabolism, including arrested progression toward mature skeletal lineages in the KO group. A single systemic injection of CTRP3 protein at the time of fracture was insufficient to phenocopy the chronic TG healing response in WT mice. By associating CTRP3 levels with fracture healing progression, these data identify a novel protein family with potential therapeutic and diagnostic value. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:00-19966, 2020.
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Affiliation(s)
- Daniel W. Youngstrom
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA;,Department of Orthopaedic Surgery, University of Connecticut Health Center, Farmington, Connecticut, USA;,Correspondence should be addressed to Dr. Daniel W. Youngstrom:
| | - Robert L. Zondervan
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA;,Department of Physiology, Michigan State University College of Osteopathic Medicine, East Lansing, Michigan, USA
| | - Nicole R. Doucet
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Parker K. Acevedo
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Hannah E. Sexton
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Emily A. Gardner
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - JonCarlos S. Anderson
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Priyanka Kushwaha
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hannah C. Little
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Susana Rodriguez
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Ivo Kalajzic
- Department of Reconstructive Sciences, University of Connecticut Health Center, Farmington, Connecticut, USA
| | - G. William Wong
- Department of Physiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kurt D. Hankenson
- Department of Orthopaedic Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
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22
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Abou DS, Rittenbach A, Tomlinson RE, Finley PA, Tsui B, Simons BW, Jha AK, Ulmert D, Riddle RC, Thorek DLJ. Preclinical Single Photon Emission Computed Tomography of Alpha Particle-Emitting Radium-223. Cancer Biother Radiopharm 2020; 35:520-529. [PMID: 32182119 DOI: 10.1089/cbr.2019.3308] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Objective: Dose optimization and pharmacokinetic evaluation of α-particle emitting radium-223 dichloride (223RaCl2) by planar γ-camera or single photon emission computed tomography (SPECT) imaging are hampered by the low photon abundance and injected activities. In this study, we demonstrate SPECT of 223Ra using phantoms and small animal in vivo models. Methods: Line phantoms and mice bearing 223Ra were imaged using a dedicated small animal SPECT by detecting the low-energy photon emissions from 223Ra. Localization of the therapeutic agent was verified by whole-body and whole-limb autoradiography and its radiobiological effect confirmed by immunofluorescence. Results: A state-of-the-art commercial small animal SPECT system equipped with a highly sensitive collimator enables collection of sufficient counts for three-dimensional reconstruction at reasonable administered activities and acquisition times. Line sources of 223Ra in both air and in a water scattering phantom gave a line spread function with a full-width-at-half-maximum of 1.45 mm. Early and late-phase imaging of the pharmacokinetics of the radiopharmaceutical were captured. Uptake at sites of active bone remodeling was correlated with DNA damage from the α particle emissions. Conclusions: This work demonstrates the capability to noninvasively define the distribution of 223RaCl2, a recently approved α-particle-emitting radionuclide. This approach allows quantitative assessment of 223Ra distribution and may assist radiation-dose optimization strategies to improve therapeutic response and ultimately to enable personalized treatment planning.
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Affiliation(s)
- Diane S Abou
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA.,Program in Quantitative Molecular Therapeutics, Washington University School of Medicine, St. Louis, Missouri, USA.,Radiology Cyclotron Facility, Mallinckrodt Institute of Radiology, Washington University in St. Louis, St. Louis, Missouri, USA.,Oncologic Imaging Program, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Andrew Rittenbach
- Information Sciences Institute, University of Southern California, Los Angeles, California, USA
| | - Ryan E Tomlinson
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paige A Finley
- Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Benjamin Tsui
- Department of Radiology and Radiological Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Brian W Simons
- Center for Comparative Medicine, Baylor College of Medicine, Houston, Texas, USA
| | - Abhinav K Jha
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University, St. Louis, Missouri, USA
| | - David Ulmert
- Department of Molecular and Medical Pharmacology, University of California Los Angeles, Los Angeles, California, USA.,Division of Urological Research, Department of Clinical Sciences, Lünd University, Malmö, Sweden
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Daniel L J Thorek
- Department of Radiology, Washington University School of Medicine, St. Louis, Missouri, USA.,Program in Quantitative Molecular Therapeutics, Washington University School of Medicine, St. Louis, Missouri, USA.,Oncologic Imaging Program, Siteman Cancer Center, Washington University School of Medicine, St. Louis, Missouri, USA.,Department of Biomedical Engineering, Washington University, St. Louis, Missouri, USA
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23
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Kushwaha P, Kim S, Foxa GE, Michalski MN, Williams BO, Tomlinson RE, Riddle RC. Frizzled-4 is required for normal bone acquisition despite compensation by Frizzled-8. J Cell Physiol 2020; 235:6673-6683. [PMID: 31985040 DOI: 10.1002/jcp.29563] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 01/10/2020] [Indexed: 12/20/2022]
Abstract
The activation of the Wnt/β-catenin signaling pathway is critical for skeletal development but surprisingly little is known about the requirements for the specific frizzled (Fzd) receptors that recognize Wnt ligands. To define the contributions of individual Fzd proteins to osteoblast function, we profiled the expression of all 10 mammalian receptors during calvarial osteoblast differentiation. Expression of Fzd4 was highly upregulated during in vitro differentiation and therefore targeted for further study. Mice lacking Fzd4 in mature osteoblasts had normal cortical bone structure but reduced cortical tissue mineral density and also exhibited an impairment in the femoral trabecular bone acquisition that was secondary to a defect in the mineralization process. Consistent with this observation, matrix mineralization, markers of osteoblastic differentiation, and the ability of Wnt3a to stimulate the accumulation of β-catenin were reduced in cultures of calvarial osteoblasts deficient for Fzd4. Interestingly, Fzd4-deficient osteoblasts exhibited an increase in the expression of Fzd8 both in vitro and in vivo, which suggests that the two receptors may exhibit overlapping functions. Indeed, ablating a single Fzd8 allele in osteoblast-specific Fzd4 mutants produced a more severe effect on bone acquisition. Taken together, our data indicate that Fzd4 is required for normal bone development and mineralization despite compensation from Fzd8.
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Affiliation(s)
- Priyanka Kushwaha
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Soohyun Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Gabrielle E Foxa
- Program for Skeletal Disease and Tumor Microenvironment and Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan
| | - Megan N Michalski
- Program for Skeletal Disease and Tumor Microenvironment and Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan
| | - Bart O Williams
- Program for Skeletal Disease and Tumor Microenvironment and Center for Cancer and Cell Biology, Van Andel Research Institute, Grand Rapids, Michigan
| | - Ryan E Tomlinson
- Department of Orthopaedic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland.,Research and Development Service, Baltimore Veterans Administration Medical Center, Baltimore, Maryland
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24
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Abstract
The skeleton is a dynamic and metabolically active organ with the capacity to influence whole body metabolism. This newly recognized function has propagated interest in the connection between bone health and metabolic dysfunction. Osteoblasts, the specialized mesenchymal cells responsible for the production of bone matrix and mineralization, rely on multiple fuel sources. The utilization of glucose by osteoblasts has long been a focus of research, however, lipids and their derivatives, are increasingly recognized as a vital energy source. Osteoblasts possess the necessary receptors and catabolic enzymes for internalization and utilization of circulating lipids. Disruption of these processes can impair osteoblast function, resulting in skeletal deficits while simultaneously altering whole body lipid homeostasis. This article provides an overview of the metabolism of postprandial and stored lipids and the osteoblast's ability to acquire and utilize these molecules. We focus on the requirement for fatty acid oxidation and the pathways regulating this function as well as the negative impact of dyslipidemia on the osteoblast and skeletal health. These findings provide key insights into the nuances of lipid metabolism in influencing skeletal homeostasis which are critical to appreciate the extent of the osteoblast's role in metabolic homeostasis.
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Affiliation(s)
- Nathalie S. Alekos
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
| | - Megan C. Moorer
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Baltimore Veterans Administration Medical Center, Baltimore, MD, United States
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, United States
- Baltimore Veterans Administration Medical Center, Baltimore, MD, United States
- *Correspondence: Ryan C. Riddle
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25
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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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26
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Fahrner JA, Lin WY, Riddle RC, Boukas L, DeLeon VB, Chopra S, Lad SE, Luperchio TR, Hansen KD, Bjornsson HT. Precocious chondrocyte differentiation disrupts skeletal growth in Kabuki syndrome mice. JCI Insight 2019; 4:129380. [PMID: 31557133 DOI: 10.1172/jci.insight.129380] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 09/11/2019] [Indexed: 12/12/2022] Open
Abstract
Kabuki syndrome 1 (KS1) is a Mendelian disorder of the epigenetic machinery caused by mutations in the gene encoding KMT2D, which methylates lysine 4 on histone H3 (H3K4). KS1 is characterized by intellectual disability, postnatal growth retardation, and distinct craniofacial dysmorphisms. A mouse model (Kmt2d+/βGeo) exhibits features of the human disorder and has provided insight into other phenotypes; however, the mechanistic basis of skeletal abnormalities and growth retardation remains elusive. Using high-resolution micro-CT, we show that Kmt2d+/βGeo mice have shortened long bones and ventral bowing of skulls. In vivo expansion of growth plates within skulls and long bones suggests disrupted endochondral ossification as a common disease mechanism. Stable chondrocyte cell lines harboring inactivating mutations in Kmt2d exhibit precocious differentiation, further supporting this mechanism. A known inducer of chondrogenesis, SOX9, and its targets show markedly increased expression in Kmt2d-/- chondrocytes. By transcriptome profiling, we identify Shox2 as a putative KMT2D target. We propose that decreased KMT2D-mediated H3K4me3 at Shox2 releases Sox9 inhibition and thereby leads to enhanced chondrogenesis, providing a potentially novel and plausible explanation for precocious chondrocyte differentiation. Our findings provide insight into the pathogenesis of growth retardation in KS1 and suggest therapeutic approaches for this and related disorders.
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Affiliation(s)
- Jill A Fahrner
- McKusick-Nathans Institute of Genetic Medicine.,Department of Pediatrics
| | | | | | - Leandros Boukas
- McKusick-Nathans Institute of Genetic Medicine.,Department of Biostatistics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Valerie B DeLeon
- Department of Anthropology, University of Florida, Gainesville, Florida, USA
| | | | - Susan E Lad
- Department of Anthropology, University of Florida, Gainesville, Florida, USA
| | | | - Kasper D Hansen
- McKusick-Nathans Institute of Genetic Medicine.,Department of Biostatistics, Johns Hopkins University, Baltimore, Maryland, USA
| | - Hans T Bjornsson
- McKusick-Nathans Institute of Genetic Medicine.,Department of Pediatrics.,Landspitali University Hospital, Reykjavik, Iceland.,Faculty of Medicine, University of Iceland, Reykjavik, Iceland
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27
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Hughes RM, Simons BW, Khan H, Miller R, Kugler V, Torquato S, Theodros D, Haffner MC, Lotan T, Huang J, Davicioni E, An SS, Riddle RC, Thorek DLJ, Garraway IP, Fertig EJ, Isaacs JT, Brennen WN, Park BH, Hurley PJ. Asporin Restricts Mesenchymal Stromal Cell Differentiation, Alters the Tumor Microenvironment, and Drives Metastatic Progression. Cancer Res 2019; 79:3636-3650. [PMID: 31123087 DOI: 10.1158/0008-5472.can-18-2931] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 04/17/2019] [Accepted: 05/20/2019] [Indexed: 12/17/2022]
Abstract
Tumor progression to metastasis is not cancer cell autonomous, but rather involves the interplay of multiple cell types within the tumor microenvironment. Here we identify asporin (ASPN) as a novel, secreted mesenchymal stromal cell (MSC) factor in the tumor microenvironment that regulates metastatic development. MSCs expressed high levels of ASPN, which decreased following lineage differentiation. ASPN loss impaired MSC self-renewal and promoted terminal cell differentiation. Mechanistically, secreted ASPN bound to BMP-4 and restricted BMP-4-induced MSC differentiation prior to lineage commitment. ASPN expression was distinctly conserved between MSC and cancer-associated fibroblasts (CAF). ASPN expression in the tumor microenvironment broadly impacted multiple cell types. Prostate tumor allografts in ASPN-null mice had a reduced number of tumor-associated MSCs, fewer cancer stem cells, decreased tumor vasculature, and an increased percentage of infiltrating CD8+ T cells. ASPN-null mice also demonstrated a significant reduction in lung metastases compared with wild-type mice. These data establish a role for ASPN as a critical MSC factor that extensively affects the tumor microenvironment and induces metastatic progression. SIGNIFICANCE: These findings show that asporin regulates key properties of mesenchymal stromal cells, including self-renewal and multipotency, and asporin expression by reactive stromal cells alters the tumor microenvironment and promotes metastatic progression.
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Affiliation(s)
- Robert M Hughes
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Brian W Simons
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Hamda Khan
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Rebecca Miller
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Valentina Kugler
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Samantha Torquato
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Debebe Theodros
- The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Michael C Haffner
- The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Tamara Lotan
- The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Pathology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Jessie Huang
- The Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Elai Davicioni
- Genome Dx Biosciences, Inc., Vancouver, British Columbia, Canada
| | - Steven S An
- The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland.,The Whiting School of Engineering, Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Ryan C Riddle
- The Department of Orthopedic Surgery, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Daniel L J Thorek
- The Department of Radiology, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Isla P Garraway
- The Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, California
| | - Elana J Fertig
- The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - John T Isaacs
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - W Nathaniel Brennen
- The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
| | - Ben H Park
- The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Whiting School of Engineering, Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, Maryland
| | - Paula J Hurley
- The James Buchanan Brady Urological Institute, Department of Urology, Johns Hopkins School of Medicine, Baltimore, Maryland. .,The Department of Oncology, Johns Hopkins School of Medicine, Baltimore, Maryland.,The Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins School of Medicine, Baltimore, Maryland
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28
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Rindone AN, Kachniarz B, Achebe CC, Riddle RC, O'Sullivan AN, Dorafshar AH, Grayson WL. Craniofacial Bone‐Tissue Engineering: Heparin‐Conjugated Decellularized Bone Particles Promote Enhanced Osteogenic Signaling of PDGF‐BB to Adipose‐Derived Stem Cells in Tissue Engineered Bone Grafts (Adv. Healthcare Mater. 10/2019). Adv Healthc Mater 2019. [DOI: 10.1002/adhm.201970042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Alexandra N. Rindone
- Translational Tissue Engineering CenterJohns Hopkins University School of Medicine Baltimore MD 21287 USA
- Department of Biomedical EngineeringJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Bartlomiej Kachniarz
- Department of Plastic and Reconstructive SurgeryJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Chukwuebuka C. Achebe
- Department of Biomedical EngineeringJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Ryan C. Riddle
- Department of Orthopaedic SurgeryJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Aine N. O'Sullivan
- Translational Tissue Engineering CenterJohns Hopkins University School of Medicine Baltimore MD 21287 USA
| | - Amir H. Dorafshar
- Department of Plastic and Reconstructive SurgeryJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Warren L. Grayson
- Translational Tissue Engineering CenterJohns Hopkins University School of Medicine Baltimore MD 21287 USA
- Department of Biomedical EngineeringJohns Hopkins University School of Medicine Baltimore MD 21205 USA
- Department of Materials Science and EngineeringJohns Hopkins University Baltimore MD 21218 USA
- Institute for NanoBioTechnologyJohns Hopkins University Baltimore MD 21218 USA
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29
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Rindone AN, Kachniarz B, Achebe CC, Riddle RC, O'Sullivan AN, Dorafshar AH, Grayson WL. Heparin-Conjugated Decellularized Bone Particles Promote Enhanced Osteogenic Signaling of PDGF-BB to Adipose-Derived Stem Cells in Tissue Engineered Bone Grafts. Adv Healthc Mater 2019; 8:e1801565. [PMID: 30941920 DOI: 10.1002/adhm.201801565] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 02/17/2019] [Indexed: 12/29/2022]
Abstract
Adipose-derived stem cells (ASCs) are a promising cell source for regenerating critical-sized craniofacial bone defects, but their clinical use is limited due to the supraphysiological levels of bone morphogenetic protein-2 required to induce bone formation in large grafts. It has been recently reported that platelet-derived growth factor-BB (PDGF) directly enhances the osteogenesis of ASCs when applied at physiological concentrations. In this study, a biomimetic delivery system that tethers PDGF to decellularized bone matrix (DCB) is developed to enhance osteogenic signaling in bone grafts by colocalizing PDGF-extracellular matrix cues. Heparin is conjugated to DCB particles (HC-DCB) to promote sustained binding of PDGF via electrostatic interactions. HC-DCB particles bind to PDGF with >99% efficiency and release significantly less PDGF over 21 days compared to nonconjugated DCB particles (1.1% vs 22.8%). HC-DCB-PDGF signaling in polycaprolactone (PCL)-fibrin grafts promotes >40 µg Ca2+ µg-1 DNA deposition by ASCs during in vitro osteogenic culture compared to grafts without HC-DCB or PDGF. Furthermore, more bone formation is observed in grafts with HC-DCB-PDGF at 12 weeks following implantation of grafts into murine critical-sized calvarial defects. Collectively, these results demonstrate that HC-DCB enhances the osteogenic signaling of PDGF to ASCs and may be applied to promote ASC-mediated bone regeneration in critical-sized defects.
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Affiliation(s)
- Alexandra N. Rindone
- Translational Tissue Engineering CenterJohns Hopkins University School of Medicine Baltimore MD 21287 USA
- Department of Biomedical EngineeringJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Bartlomiej Kachniarz
- Department of Plastic and Reconstructive SurgeryJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Chukwuebuka C. Achebe
- Department of Biomedical EngineeringJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Ryan C. Riddle
- Department of Orthopaedic SurgeryJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Aine N. O'Sullivan
- Translational Tissue Engineering CenterJohns Hopkins University School of Medicine Baltimore MD 21287 USA
| | - Amir H. Dorafshar
- Department of Plastic and Reconstructive SurgeryJohns Hopkins University School of Medicine Baltimore MD 21205 USA
| | - Warren L. Grayson
- Translational Tissue Engineering CenterJohns Hopkins University School of Medicine Baltimore MD 21287 USA
- Department of Biomedical EngineeringJohns Hopkins University School of Medicine Baltimore MD 21205 USA
- Department of Materials Science and EngineeringJohns Hopkins University Baltimore MD 21218 USA
- Institute for NanoBioTechnologyJohns Hopkins University Baltimore MD 21218 USA
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30
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Kim SP, Da H, Li Z, Kushwaha P, Beil C, Mei L, Xiong WC, Wolfgang MJ, Clemens TL, Riddle RC. Lrp4 expression by adipocytes and osteoblasts differentially impacts sclerostin's endocrine effects on body composition and glucose metabolism. J Biol Chem 2019; 294:6899-6911. [PMID: 30842262 DOI: 10.1074/jbc.ra118.006769] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 02/23/2019] [Indexed: 01/10/2023] Open
Abstract
Sclerostin exerts profound local control over bone acquisition and also mediates endocrine communication between fat and bone. In bone, sclerostin's anti-osteoanabolic activity is enhanced by low-density lipoprotein receptor-related protein 4 (Lrp4), which facilitates its interaction with the Lrp5 and Lrp6 Wnt co-receptors. To determine whether Lrp4 similarly affects sclerostin's endocrine function, we examined body composition as well as glucose and fatty acid metabolism in mice rendered deficient of Lrp4 in the adipocyte (AdΔLrp4) or the osteoblast (ObΔLrp4). AdΔLrp4 mice exhibit a reduction in adipocyte hypertrophy and improved glucose and lipid homeostasis, marked by increased glucose and insulin tolerance and reduced serum fatty acids, and mirror the effect of sclerostin deficiency on whole-body metabolism. Indeed, epistasis studies place adipocyte-expressed Lrp4 and sclerostin in the same genetic cascade that regulates adipocyte function. Intriguingly, ObΔLrp4 mice, which exhibit dramatic increases in serum sclerostin, accumulate body fat and develop impairments in glucose tolerance and insulin sensitivity despite development of a high bone mass phenotype. These data indicate that expression of Lrp4 by both the adipocyte and osteoblast is required for normal sclerostin endocrine function and that the impact of sclerostin deficiency on adipocyte physiology is distinct from the effect on osteoblast function.
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Affiliation(s)
| | - Hao Da
- From the Departments of Orthopedic Surgery and
| | - Zhu Li
- From the Departments of Orthopedic Surgery and
| | | | - Conor Beil
- From the Departments of Orthopedic Surgery and
| | - Lin Mei
- the Department of Neuroscience, Case Western Reserve University Medical School, Cleveland, Ohio 44106, and
| | - Wen-Cheng Xiong
- the Department of Neuroscience, Case Western Reserve University Medical School, Cleveland, Ohio 44106, and
| | - Michael J Wolfgang
- Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Thomas L Clemens
- From the Departments of Orthopedic Surgery and.,the Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201
| | - Ryan C Riddle
- From the Departments of Orthopedic Surgery and .,the Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201
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31
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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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32
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Abstract
Wnt/β-catenin signaling plays a critical role in the achievement of peak bone mass, affecting the commitment of mesenchymal progenitors to the osteoblast lineage and the anabolic capacity of osteoblasts depositing bone matrix. Recent studies suggest that this evolutionarily-conserved, developmental pathway exerts its anabolic effects in part by coordinating osteoblast activity with intermediary metabolism. These findings are compatible with the cloning of the gene encoding the low-density lipoprotein related receptor-5 (LRP5) Wnt co-receptor from a diabetes-susceptibility locus and the now well-established linkage between Wnt signaling and metabolism. In this article, we provide an overview of the role of Wnt signaling in whole-body metabolism and review the literature regarding the impact of Wnt signaling on the osteoblast's utilization of three different energy sources: fatty acids, glucose, and glutamine. Special attention is devoted to the net effect of nutrient utilization and the mode of regulation by Wnt signaling. Mechanistic studies indicate that the utilization of each substrate is governed by a unique mechanism of control with β-catenin-dependent signaling regulating fatty acid β-oxidation, while glucose and glutamine utilization are β-catenin-independent and downstream of mammalian target of rapamycin complex 2 (mTORC2) and mammalian target of rapamycin complex 1 (mTORC1) activation, respectively. The emergence of these data has provided a new context for the mechanisms by which Wnt signaling influences bone development.
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Affiliation(s)
- Megan C Moorer
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Baltimore Veterans Administration Medical Center, 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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33
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Ziegler SG, Ferreira CR, MacFarlane EG, Riddle RC, Tomlinson RE, Chew EY, Martin L, Ma CT, Sergienko E, Pinkerton AB, Millán JL, Gahl WA, Dietz HC. Ectopic calcification in pseudoxanthoma elasticum responds to inhibition of tissue-nonspecific alkaline phosphatase. Sci Transl Med 2018; 9:9/393/eaal1669. [PMID: 28592560 DOI: 10.1126/scitranslmed.aal1669] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2016] [Revised: 01/10/2017] [Accepted: 04/25/2017] [Indexed: 12/26/2022]
Abstract
Biallelic mutations in ABCC6 cause pseudoxanthoma elasticum (PXE), a disease characterized by calcification in the skin, eyes, and blood vessels. The function of ATP-binding cassette C6 (ABCC6) and the pathogenesis of PXE remain unclear. We used mouse models and patient fibroblasts to demonstrate genetic interaction and shared biochemical and cellular mechanisms underlying ectopic calcification in PXE and related disorders caused by defined perturbations in extracellular adenosine 5'-triphosphate catabolism. Under osteogenic culture conditions, ABCC6 mutant cells calcified, suggesting a provoked cell-autonomous defect. Using a conditional Abcc6 knockout mouse model, we excluded the prevailing pathogenic hypothesis that singularly invokes failure of hepatic secretion of an endocrine inhibitor of calcification. Instead, deficiency of Abcc6 in both local and distant cells was necessary to achieve the early onset and penetrant ectopic calcification observed upon constitutive gene targeting. ABCC6 mutant cells additionally had increased expression and activity of tissue-nonspecific alkaline phosphatase (TNAP), an enzyme that degrades pyrophosphate, a major inhibitor of calcification. A selective and orally bioavailable TNAP inhibitor prevented calcification in ABCC6 mutant cells in vitro and attenuated both the development and progression of calcification in Abcc6-/- mice in vivo, without the deleterious effects on bone associated with other proposed treatment strategies.
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Affiliation(s)
- Shira G Ziegler
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Carlos R Ferreira
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Elena Gallo MacFarlane
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.,Baltimore Veterans Administrations Medical Center, Baltimore, MD 21201, USA
| | - Ryan E Tomlinson
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Emily Y Chew
- National Eye Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Ludovic Martin
- PXE Reference Center and MitoVasc Institute, Angers University Hospital, Angers, France
| | - Chen-Ting Ma
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - Eduard Sergienko
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | | | - José Luis Millán
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA 92037, USA
| | - William A Gahl
- Medical Genetics Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, MD 20814, USA
| | - Harry C Dietz
- Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA. .,Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA
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34
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Frey JL, Kim SP, Li Z, Wolfgang MJ, Riddle RC. β-Catenin Directs Long-Chain Fatty Acid Catabolism in the Osteoblasts of Male Mice. Endocrinology 2018; 159:272-284. [PMID: 29077850 PMCID: PMC5761587 DOI: 10.1210/en.2017-00850] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Accepted: 10/20/2017] [Indexed: 11/19/2022]
Abstract
Wnt-initiated signaling through a frizzled receptor and the low-density lipoprotein-related receptor-5 coreceptor instructs key anabolic events during skeletal development, homeostasis, and repair. Recent studies indicate that Wnt signaling also regulates the intermediary metabolism of osteoblastic cells, inducing glucose consumption in osteoprogenitors and fatty acid utilization in mature osteoblasts. In this study, we examined the role of the canonical Wnt-signaling target, β-catenin, in the control of osteoblast metabolism. In vitro, Wnt ligands and agonists that stimulated β-catenin activation in osteoblasts enhanced fatty acid catabolism, whereas genetic ablation of β-catenin dramatically reduced oleate oxidation concomitant with reduced osteoblast maturation and increased glycolytic metabolism. Temporal ablation of β-catenin expression in osteoblasts in vivo produced the expected low-bone-mass phenotype and also led to an increase in white adipose tissue mass, dyslipidemia, and impaired insulin sensitivity. Because the expression levels of enzymatic mediators of fatty acid β-oxidation are reduced in the skeleton of β-catenin mutants, these results further confirm the role of the osteoblast in lipid metabolism and indicate that the influence of Wnt signaling on fatty acid utilization proceeds via its canonical signaling pathway.
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MESH Headings
- Adipose Tissue, White/cytology
- Adipose Tissue, White/metabolism
- Adiposity
- Animals
- Animals, Newborn
- Caloric Restriction
- Cells, Cultured
- Crosses, Genetic
- Fatty Acids, Nonesterified/metabolism
- Gene Expression Regulation, Developmental
- Ligands
- Lipid Metabolism
- Male
- Mice, Inbred C57BL
- Mice, Mutant Strains
- Mice, Transgenic
- Mutation
- Osteoblasts/cytology
- Osteoblasts/metabolism
- Random Allocation
- Skull/cytology
- Skull/metabolism
- Wnt Proteins/genetics
- Wnt Proteins/metabolism
- Wnt Signaling Pathway
- beta Catenin/genetics
- beta Catenin/metabolism
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Affiliation(s)
- Julie L. Frey
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Soohyun P. Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Zhu Li
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Michael J. Wolfgang
- Department of Biological Chemistry, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Veterans Administration Medical Center, Baltimore, Maryland 21201
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Kim SP, Frey JL, Li Z, Kushwaha P, Zoch ML, Tomlinson RE, Da H, Aja S, Noh HL, Kim JK, Hussain MA, Thorek DLJ, Wolfgang MJ, Riddle RC. Sclerostin influences body composition by regulating catabolic and anabolic metabolism in adipocytes. Proc Natl Acad Sci U S A 2017; 114:E11238-E11247. [PMID: 29229807 PMCID: PMC5748171 DOI: 10.1073/pnas.1707876115] [Citation(s) in RCA: 102] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Sclerostin has traditionally been thought of as a local inhibitor of bone acquisition that antagonizes the profound osteoanabolic capacity of activated Wnt/β-catenin signaling, but serum sclerostin levels in humans exhibit a correlation with impairments in several metabolic parameters. These data, together with the increased production of sclerostin in mouse models of type 2 diabetes, suggest an endocrine function. To determine whether sclerostin contributes to the coordination of whole-body metabolism, we examined body composition, glucose homeostasis, and fatty acid metabolism in Sost-/- mice as well as mice that overproduce sclerostin as a result of adeno-associated virus expression from the liver. Here, we show that in addition to dramatic increases in bone volume, Sost-/- mice exhibit a reduction in adipose tissue accumulation in association with increased insulin sensitivity. Sclerostin overproduction results in the opposite metabolic phenotype due to adipocyte hypertrophy. Additionally, Sost-/- mice and those administered a sclerostin-neutralizing antibody are resistant to obesogenic diet-induced disturbances in metabolism. This effect appears to be the result of sclerostin's effects on Wnt signaling and metabolism in white adipose tissue. Since adipocytes do not produce sclerostin, these findings suggest an unexplored endocrine function for sclerostin that facilitates communication between the skeleton and adipose tissue.
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Affiliation(s)
- Soohyun P Kim
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Julie L Frey
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Zhu Li
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Priyanka Kushwaha
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Meredith L Zoch
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ryan E Tomlinson
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Hao Da
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Susan Aja
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Hye Lim Noh
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655
| | - Jason K Kim
- Program in Molecular Medicine, University of Massachusetts Medical School, Worcester, MA 01655
- Department of Medicine, Division of Endocrinology and Metabolism, University of Massachusetts Medical School, Worcester, MA 01655
- Department of Medicine, Division of Diabetes, University of Massachusetts Medical School, Worcester, MA 01655
| | - Mehboob A Hussain
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Pediatrics, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Daniel L J Thorek
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiologic Sciences, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Cancer Molecular and Functional Imaging Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Michael J Wolfgang
- Center for Metabolism and Obesity Research, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
- Department of Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, The Johns Hopkins University School of Medicine, Baltimore, MD 21205;
- Baltimore Veterans Administration Medical Center, Baltimore, MD 21201
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Kim SP, Frey JL, Li Z, Goh BC, Riddle RC. Lack of Lrp5 Signaling in Osteoblasts Sensitizes Male Mice to Diet-Induced Disturbances in Glucose Metabolism. Endocrinology 2017; 158:3805-3816. [PMID: 28938444 PMCID: PMC5695825 DOI: 10.1210/en.2017-00657] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/21/2017] [Accepted: 09/06/2017] [Indexed: 01/16/2023]
Abstract
Wnt signaling through the low-density lipoprotein-related receptor 5 (Lrp5) coreceptor regulates osteoblast maturation, matrix mineralization, and intermediary metabolism. In the mature osteoblast, signals downstream of Lrp5 are required for normal long-chain fatty acid β-oxidation. Mice rendered deficient for this coreceptor in osteoblasts and osteocytes accumulate body fat with elevated serum lipid levels but retain normal insulin sensitivity. In the present study, we challenged Lrp5-mutant mice with a high-fat diet (HFD) to determine whether they were more susceptible to diet-induced disturbances in glucose homeostasis. The HFD-fed Lrp5 mutant mice maintained a low bone mass phenotype with an increase in adipose tissue mass and hypertriglyceridemia and hypercholesterolemia. Examination of glucose metabolism revealed that Lrp5 deficiency in the osteoblast also resulted in hyperglycemia and hyperinsulinemia, with reductions in glucose tolerance, insulin sensitivity, and serum undercarboxylated osteocalcin. The results from in vivo genetic epistasis and in vitro studies suggest that this phenotype proceeds via the accumulation of diacylglycerol species and impaired insulin signaling in Lrp5-deficient osteoblasts. In turn, glucose uptake and osteocalcin production are diminished in mutant osteoblasts. Taken together, these data identify a link between Wnt-Lrp5 signaling and insulin signaling in the osteoblast that has the potential to influence energy balance and compound the detrimental effects of a HFD on whole-body metabolism.
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Affiliation(s)
- Soohyun P. Kim
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Julie L. Frey
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Zhu Li
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Brian C. Goh
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
| | - Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205
- Baltimore Veterans Affairs Medical Center, Baltimore, Maryland 21201
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Kim SP, Li Z, Zoch ML, Frey JL, Bowman CE, Kushwaha P, Ryan KA, Goh BC, Scafidi S, Pickett JE, Faugere MC, Kershaw EE, Thorek DLJ, Clemens TL, Wolfgang MJ, Riddle RC. Fatty acid oxidation by the osteoblast is required for normal bone acquisition in a sex- and diet-dependent manner. JCI Insight 2017; 2:92704. [PMID: 28814665 DOI: 10.1172/jci.insight.92704] [Citation(s) in RCA: 75] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 07/19/2017] [Indexed: 12/20/2022] Open
Abstract
Postnatal bone formation is influenced by nutritional status and compromised by disturbances in metabolism. The oxidation of dietary lipids represents a critical source of ATP for many cells but has been poorly studied in the skeleton, where the prevailing view is that glucose is the primary energy source. Here, we examined fatty acid uptake by bone and probed the requirement for fatty acid catabolism during bone formation by specifically disrupting the expression of carnitine palmitoyltransferase 2 (Cpt2), an obligate enzyme in fatty acid oxidation, in osteoblasts and osteocytes. Radiotracer studies demonstrated that the skeleton accumulates a significant fraction of postprandial fatty acids, which was equal to or in excess of that acquired by skeletal muscle or adipose tissue. Female, but not male, Cpt2 mutant mice exhibited significant impairments in postnatal bone acquisition, potentially due to an inability of osteoblasts to modify fuel selection. Intriguingly, suppression of fatty acid utilization by osteoblasts and osteocytes also resulted in the development of dyslipidemia and diet-dependent modifications in body composition. Taken together, these studies demonstrate a requirement for fatty acid oxidation during bone accrual and suggest a role for the skeleton in lipid homeostasis.
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Affiliation(s)
| | - Zhu Li
- Department of Orthopaedic Surgery
| | | | | | | | | | | | | | - Susanna Scafidi
- Department of Anesthesiology and Critical Care Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Julie E Pickett
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | | | - Erin E Kershaw
- Division of Endocrinology, Department of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Daniel L J Thorek
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Cancer Molecular and Functional Imaging Program, Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Thomas L Clemens
- Department of Orthopaedic Surgery.,Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
| | | | - Ryan C Riddle
- Department of Orthopaedic Surgery.,Baltimore Veterans Administration Medical Center, Baltimore, Maryland, USA
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Abstract
The rising incidence of metabolic diseases worldwide has prompted renewed interest in the study of intermediary metabolism and cellular bioenergetics. The application of modern biochemical methods for quantitating fuel substrate metabolism with advanced mouse genetic approaches has greatly increased understanding of the mechanisms that integrate energy metabolism in the whole organism. Examination of the intermediary metabolism of skeletal cells has been sparked by a series of unanticipated observations in genetically modified mice that suggest the existence of novel endocrine pathways through which bone cells communicate their energy status to other centers of metabolic control. The recognition of this expanded role of the skeleton has in turn led to new lines of inquiry directed at defining the fuel requirements and bioenergetic properties of bone cells. This article provides a comprehensive review of historical and contemporary studies on the metabolic properties of bone cells and the mechanisms that control energy substrate utilization and bioenergetics. Special attention is devoted to identifying gaps in our current understanding of this new area of skeletal biology that will require additional research to better define the physiological significance of skeletal cell bioenergetics in human health and disease.
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Affiliation(s)
- Ryan C Riddle
- Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, Maryland; and The Baltimore Veterans Administration Medical Center, Baltimore, Maryland
| | - Thomas L Clemens
- Department of Orthopaedic Surgery, The Johns Hopkins University, Baltimore, Maryland; and The Baltimore Veterans Administration Medical Center, Baltimore, Maryland
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Li Z, Frey JL, Wong GW, Faugere MC, Wolfgang MJ, Kim JK, Riddle RC, Clemens TL. Glucose Transporter-4 Facilitates Insulin-Stimulated Glucose Uptake in Osteoblasts. Endocrinology 2016; 157:4094-4103. [PMID: 27689415 PMCID: PMC5086531 DOI: 10.1210/en.2016-1583] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent studies have identified the osteoblast as an insulin responsive cell that participates in global energy homeostasis. Here, we show that glucose transporter-4 (Glut4) is required for insulin-dependent uptake and oxidation of glucose in mature osteoblasts. In primary cultures of mouse osteoblasts, insulin increased uptake and oxidation of 14C-glucose in a dose-dependent fashion but did not significantly affect uptake or oxidation of 14C-oleate. In vitro, undifferentiated osteoblasts expressed 3 high-affinity Gluts: Glut1, Glut4, and Glut3. However, although levels of Glut1 and Glut3 remained constant during the course of osteoblast differentiation, Glut4 expression increased by 5-fold in association with enhanced insulin-stimulated glucose uptake. Glut4 ablation in osteoblasts in vitro eliminated insulin-stimulated glucose uptake, reduced proliferation and diminished measures of osteoblast maturation. In vivo, Glut4 expression was observed in osteoblasts, osteocytes, and chondrocytes at a level approaching that observed in adjacent skeletal muscle. To determine the importance of Glut4 in bone in vivo, we generated mice lacking Glut4 in osteoblasts and osteocytes (ΔGlut4). ΔGlut4 mice exhibited normal bone architecture but exhibited an increase in peripheral fat in association with hyperinsulinemia, β-cell islet hypertrophy, and reduced insulin sensitivity. Surprisingly, the expression of insulin target genes in liver, muscle, and adipose from ΔGlut4 mice were unchanged or increased, indicating that alterations in glucose homeostasis were the result of reduced clearance by bone. These findings suggest that Glut4 mediates insulin-stimulated glucose uptake by mature osteoblasts/osteocytes and that the magnitude of glucose use by bone cells is sufficient to impact global glucose disposal in the mouse.
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Affiliation(s)
- Zhu Li
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
| | - Julie L Frey
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
| | - G William Wong
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
| | - Marie-Claude Faugere
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
| | - Michael J Wolfgang
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
| | - Jason K Kim
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
| | - Ryan C Riddle
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
| | - Thomas L Clemens
- Department of Orthopaedic Surgery (Z.L., J.L.F., R.C.R., T.L.C.), Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Physiology (G.W.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Department of Medicine (M.-C.F.), Division of Nephology, University of Kentucky, Lexington, Kentucky 40356; Department of Biological Chemistry (M.J.W.), Center for Metabolism and Obesity Research, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205; Program in Molecular Medicine (J.K.K.), University of Massachusetts Medical School, Wooster, Massachusetts 01605; and Baltimore Veterans Administration Medical Center (R.C.R., T.L.C.), Baltimore, Maryland 21201
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Zoch ML, Abou DS, Clemens TL, Thorek DLJ, Riddle RC. In vivo radiometric analysis of glucose uptake and distribution in mouse bone. Bone Res 2016; 4:16004. [PMID: 27088042 PMCID: PMC4820746 DOI: 10.1038/boneres.2016.4] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Revised: 01/25/2016] [Accepted: 01/26/2016] [Indexed: 01/27/2023] Open
Abstract
Bone formation and remodeling occurs throughout life and requires the sustained activity of osteoblasts and osteoclasts, particularly during periods of rapid bone growth. Despite increasing evidence linking bone cell activity to global energy homeostasis, little is known about the relative energy requirements or substrate utilization of bone cells. In these studies, we measured the uptake and distribution of glucose in the skeleton in vivo using positron-emitting 18F-fluorodeoxyglucose ([18F]-FDG) and non-invasive, high-resolution positron emission tomography/computed tomography (PET/CT) imaging and ex vivo autoradiography. Assessment of [18F]-FDG uptake demonstrated that relative to other tissues bone accumulated a significant fraction of the total dose of the glucose analog. Skeletal accumulation was greatest in young mice undergoing the rapid bone formation that characterizes early development. PET/CT imaging revealed that [18F]-FDG uptake was greatest in the epiphyseal and metaphyseal regions of long bones, which accords with the increased osteoblast numbers and activity at this skeletal site. Insulin administration significantly increased skeletal accumulation of [18F]-FDG, while uptake was reduced in mice lacking the insulin receptor specifically in osteoblasts or fed a high-fat diet. Our results indicated that the skeleton is a site of significant glucose uptake and that its consumption by bone cells is subject to regulation by insulin and disturbances in whole-body metabolism.
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Affiliation(s)
- Meredith L Zoch
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine , Baltimore, USA
| | - Diane S Abou
- Division of Nuclear Medicine an Molecular Imaging, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine , Baltimore, USA
| | - Thomas L Clemens
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, USA; Baltimore Veterans Administration Medical Center, Baltimore, USA
| | - Daniel L J Thorek
- Division of Nuclear Medicine an Molecular Imaging, Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, USA; Department of Oncology, Cancer Molecular and Functional Imaging Program, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, USA; Baltimore Veterans Administration Medical Center, Baltimore, USA
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Abstract
Osteocalcin is among the most abundant proteins in bone and is produced exclusively by osteoblasts. Initially believed to be an inhibitor of bone mineralization, recent studies suggest a broader role for osteocalcin that extends to the regulation of whole body metabolism, reproduction, and cognition. Circulating undercarboxylated osteocalcin, which is regulated by insulin, acts in a feed-forward loop to increase β-cell proliferation as well as insulin production and secretion, while skeletal muscle and adipose tissue respond to osteocalcin by increasing their sensitivity to insulin. Osteocalcin also acts in the brain to increase neurotransmitter production and in the testes to stimulate testosterone production. At least one putative receptor for osteocalcin, Gprc6a, is expressed by adipose, skeletal muscle, and the Leydig cells of the testes and appears to mediate osteocalcin's effects in these tissues. In this review, we summarize these new discoveries, which suggest that the ability of osteocalcin to function both locally in bone and as a hormone depends on a novel post-translational mechanism that alters osteocalcin's affinity for the bone matrix and bioavailability. This article is part of a Special Issue entitled Bone and diabetes.
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Affiliation(s)
- Meredith L Zoch
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Thomas L Clemens
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Baltimore Veterans Administration Medical Center, 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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42
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Abou DS, Ulmert D, Doucet M, Hobbs RF, Riddle RC, Thorek DLJ. Whole-Body and Microenvironmental Localization of Radium-223 in Naïve and Mouse Models of Prostate Cancer Metastasis. J Natl Cancer Inst 2015; 108:djv380. [PMID: 26683407 PMCID: PMC4849807 DOI: 10.1093/jnci/djv380] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 11/06/2015] [Indexed: 12/16/2022] Open
Abstract
Background: Bone-metastatic, castration-resistant prostate cancer (bmCRPC) represents a lethal stage of the most common noncutaneous cancer in men. The recent introduction of Radium-223 dichloride, a bone-seeking alpha particle (α)–emitting radiopharmaceutical, demonstrates statistically significant survival benefit and palliative effect for bmCRPC patients. Clinical results have established safety and efficacy, yet questions remain regarding pharmacodynamics and dosing for optimized patient benefit. Methods: We elucidated the biodistribution of 223Ra as well as interaction with the bone and tumor compartments in skeletally mature mice (C57Bl/6 and CD-1, n = 3–6) and metastasis models (LNCaP and PC3, n = 4). Differences in uptake were evaluated by µCT and histological investigation. Novel techniques were leveraged on whole-mount undecalcified cryosections to determine microdistribution of Radium-223. All statistical tests were two-sided. Results: 223Ra uptake in the bones (>30% injected activity per gram) at 24 hours was also accompanied by non-negligible remnant activity in the kidney (2.33% ± 0.36%), intestines (5.73% ± 2.04%), and spleen (10.5% ± 5.9%) Skeletal accumulation across strains did not correspond with bone volume or surface area but instead to local blood vessel density (P = .04). Microdistribution analysis by autoradiography and α camera revealed targeting of the ossifying surfaces adjacent to the epiphyseal growth plate. In models of PCa metastasis, radioactivity does not localize directly within tumors but instead at the apposite bone surface. Osteoblastic and lytic lesions display similar intensity, which is comparable with uptake at sites of normal bone remodeling. Conclusions: Profiling the macro- and microdistribution of 223Ra in healthy and diseased models has important implications to guide precision application of this emerging α-therapy approach for bmCRPC and other bone metastastic diseases.
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Affiliation(s)
- Diane S Abou
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science (DSA, DLJT), Department of Orthopaedic Surgery (MD, RCR), Department of Radiation Oncology (RFH), and Cancer Molecular and Functional Imaging Program, Department of Oncology (RFH, DLJT), Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University (JHU) School of Medicine, Baltimore, MD; Program in Molecular Pharmacology and Chemistry, Memorial Sloan Kettering Cancer Center, New York, NY (DU); Department of Clinical Sciences (Urology), Lund University, Skåne University Hospital, Malmö, Sweden (DU)
| | - David Ulmert
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science (DSA, DLJT), Department of Orthopaedic Surgery (MD, RCR), Department of Radiation Oncology (RFH), and Cancer Molecular and Functional Imaging Program, Department of Oncology (RFH, DLJT), Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University (JHU) School of Medicine, Baltimore, MD; Program in Molecular Pharmacology and Chemistry, Memorial Sloan Kettering Cancer Center, New York, NY (DU); Department of Clinical Sciences (Urology), Lund University, Skåne University Hospital, Malmö, Sweden (DU)
| | - Michele Doucet
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science (DSA, DLJT), Department of Orthopaedic Surgery (MD, RCR), Department of Radiation Oncology (RFH), and Cancer Molecular and Functional Imaging Program, Department of Oncology (RFH, DLJT), Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University (JHU) School of Medicine, Baltimore, MD; Program in Molecular Pharmacology and Chemistry, Memorial Sloan Kettering Cancer Center, New York, NY (DU); Department of Clinical Sciences (Urology), Lund University, Skåne University Hospital, Malmö, Sweden (DU)
| | - Robert F Hobbs
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science (DSA, DLJT), Department of Orthopaedic Surgery (MD, RCR), Department of Radiation Oncology (RFH), and Cancer Molecular and Functional Imaging Program, Department of Oncology (RFH, DLJT), Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University (JHU) School of Medicine, Baltimore, MD; Program in Molecular Pharmacology and Chemistry, Memorial Sloan Kettering Cancer Center, New York, NY (DU); Department of Clinical Sciences (Urology), Lund University, Skåne University Hospital, Malmö, Sweden (DU)
| | - Ryan C Riddle
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science (DSA, DLJT), Department of Orthopaedic Surgery (MD, RCR), Department of Radiation Oncology (RFH), and Cancer Molecular and Functional Imaging Program, Department of Oncology (RFH, DLJT), Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University (JHU) School of Medicine, Baltimore, MD; Program in Molecular Pharmacology and Chemistry, Memorial Sloan Kettering Cancer Center, New York, NY (DU); Department of Clinical Sciences (Urology), Lund University, Skåne University Hospital, Malmö, Sweden (DU)
| | - Daniel L J Thorek
- Division of Nuclear Medicine and Molecular Imaging, Department of Radiology and Radiological Science (DSA, DLJT), Department of Orthopaedic Surgery (MD, RCR), Department of Radiation Oncology (RFH), and Cancer Molecular and Functional Imaging Program, Department of Oncology (RFH, DLJT), Sidney Kimmel Comprehensive Cancer Center, The Johns Hopkins University (JHU) School of Medicine, Baltimore, MD; Program in Molecular Pharmacology and Chemistry, Memorial Sloan Kettering Cancer Center, New York, NY (DU); Department of Clinical Sciences (Urology), Lund University, Skåne University Hospital, Malmö, Sweden (DU).
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43
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Affiliation(s)
- 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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Abstract
The skeleton, populated by large numbers of osteoblasts and long-lived osteocytes, requires a constant supply of energy-rich molecules to fuel the synthesis, deposition and mineralization of bone matrix during bone modelling and remodelling. When these energetic demands are not met, bone acquisition is suppressed. Recent findings suggest that key developmental signals emanating from Wnt low-density lipoprotein-related receptor 5 and hypoxia-inducible factor pathways impact osteoblast bioenergetics to accommodate the energy requirements for bone cells to fulfil their function. In vivo studies in several mutant mouse strains have confirmed a link between bone cells and global metabolism, ultimately leading to the identification of hormonal interactions between the skeleton and other tissues. The hormones insulin and leptin affect postnatal bone acquisition, whilst osteocalcin produced by the osteoblast in turn stimulates insulin secretion by the pancreas. These observations have prompted additional questions regarding the nature of the mechanisms of fuel sensing and processing in the osteoblast and their contribution to overall energy utilization and homeostasis. Answers to such questions should advance our understanding of metabolic diseases and may ultimately improve management of affected patients. In this review, we highlight recent studies in this field and offer a perspective on the evolutionary implications of bone as a metabolic endocrine organ.
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Affiliation(s)
- Q Zhang
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - R C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA.,Baltimore Veterans Administration Medical Center, Baltimore, MD, USA
| | - T L Clemens
- 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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Kanazawa I, Canaff L, Abi Rafeh J, Angrula A, Li J, Riddle RC, Boraschi-Diaz I, Komarova SV, Clemens TL, Murshed M, Hendy GN. Osteoblast menin regulates bone mass in vivo. J Biol Chem 2014; 290:3910-24. [PMID: 25538250 DOI: 10.1074/jbc.m114.629899] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Menin, the product of the multiple endocrine neoplasia type 1 (Men1) tumor suppressor gene, mediates the cell proliferation and differentiation actions of transforming growth factor-β (TGF-β) ligand family members. In vitro, menin modulates osteoblastogenesis and osteoblast differentiation promoted and sustained by bone morphogenetic protein-2 (BMP-2) and TGF-β, respectively. To examine the in vivo function of menin in bone, we conditionally inactivated Men1 in mature osteoblasts by crossing osteocalcin (OC)-Cre mice with floxed Men1 (Men1(f/f)) mice to generate mice lacking menin in differentiating osteoblasts (OC-Cre;Men1(f/f) mice). These mice displayed significant reduction in bone mineral density, trabecular bone volume, and cortical bone thickness compared with control littermates. Osteoblast and osteoclast number as well as mineral apposition rate were significantly reduced, whereas osteocyte number was increased. Primary calvarial osteoblasts proliferated more quickly but had deficient mineral apposition and alkaline phosphatase activity. Although the mRNA expression of osteoblast marker and cyclin-dependent kinase inhibitor genes were all reduced, that of cyclin-dependent kinase, osteocyte marker, and pro-apoptotic genes were increased in isolated Men1 knock-out osteoblasts compared with controls. In contrast to the knock-out mice, transgenic mice overexpressing a human menin cDNA in osteoblasts driven by the 2.3-kb Col1a1 promoter, showed a gain of bone mass relative to control littermates. Osteoblast number and mineral apposition rate were significantly increased in the Col1a1-Menin-Tg mice. Therefore, osteoblast menin plays a key role in bone development, remodeling, and maintenance.
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Affiliation(s)
| | | | | | | | | | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and the Veterans Administration Medical Center, Baltimore, Maryland 21201
| | | | | | - Thomas L Clemens
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, and the Veterans Administration Medical Center, Baltimore, Maryland 21201
| | | | - Geoffrey N Hendy
- From the Departments of Medicine, Physiology, Human Genetics, and Calcium Research Laboratory, and Hormones and Cancer Research Unit, Royal Victoria Hospital, McGill University, Montreal, Quebec H3A 1A1, Canada,
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Frey JL, Stonko DP, Faugere MC, Riddle RC. Hypoxia-inducible factor-1α restricts the anabolic actions of parathyroid hormone. Bone Res 2014; 2:14005. [PMID: 26273518 PMCID: PMC4472139 DOI: 10.1038/boneres.2014.5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2013] [Revised: 12/24/2013] [Accepted: 01/01/2014] [Indexed: 11/29/2022] Open
Abstract
The hypoxia inducible factors (Hifs) are evolutionarily conserved transcriptional factors that control homeostatic responses to low oxygen. In developing bone, Hif-1 generated signals induce angiogenesis necessary for osteoblast specification, but in mature bone, loss of Hif-1 in osteoblasts resulted in a more rapid accumulation of bone. These findings suggested that Hif-1 exerts distinct developmental functions and acts as a negative regulator of bone formation. To investigate the function of Hif-1α in osteoanabolic signaling, we assessed the effect of Hif-1α loss-of-function on bone formation in response to intermittent parathyroid hormone (PTH). Mice lacking Hif-1α in osteoblasts and osteocytes form more bone in response to PTH, likely through a larger increase in osteoblast activity and increased sensitivity to the hormone. Consistent with this effect, exposure of primary mouse osteoblasts to PTH resulted in the rapid induction of Hif-1α protein levels via a post-transcriptional mechanism. The enhanced anabolic response appears to result from the removal of Hif-1α-mediated suppression of β-catenin transcriptional activity. Together, these data indicate that Hif-1α functions in the mature skeleton to restrict osteoanabolic signaling. The availability of pharmacological agents that reduce Hif-1α function suggests the value in further exploration of this pathway to optimize the therapeutic benefits of PTH.
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Affiliation(s)
- Julie L Frey
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine , Baltimore, MD, USA
| | - David P Stonko
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine , Baltimore, MD, USA
| | - Marie-Claude Faugere
- Division of Nephrology, Bone & Mineral Metabolism, University of Kentucky , Lexington, KY, USA
| | - Ryan C Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine , Baltimore, MD, USA ; Veterans Administration Medical Center , Baltimore, MD, USA
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Abstract
Recent studies have demonstrated that insulin stimulates bone cells to produce and activate osteocalcin, an endocrine hormone that increases the efficiency of glucose metabolism through its actions on the pancreas and other peripheral tissues. In this issue of the JCI, Wei and colleagues directly explore the contribution of insulin signaling in osteoblasts to the disturbances in whole-body glucose metabolism associated with a high-fat diet. In mice fed a high-fat diet, increased uptake of saturated fatty acids by the osteoblast accelerates the ubiquitination and degradation of the insulin receptor. In this setting, impairments in osteoblast insulin signaling reduce serum levels of undercarboxylated osteocalcin, which in turn exacerbate insulin resistance in muscle and white adipose tissue. These findings underscore the importance of insulin-responsive skeletal cells as components of a newly appreciated endocrine network critical for regulating global energy homeostasis.
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48
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Bogan R, Riddle RC, Li Z, Kumar S, Nandal A, Faugere MC, Boskey A, Crawford SE, Clemens TL. A mouse model for human osteogenesis imperfecta type VI. J Bone Miner Res 2013; 28:1531-6. [PMID: 23413146 PMCID: PMC3688658 DOI: 10.1002/jbmr.1892] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Revised: 01/30/2013] [Accepted: 02/04/2013] [Indexed: 12/28/2022]
Abstract
Osteogenesis imperfecta type VI (OI type VI) has recently be linked to a mutation in the SERPINF1 gene, which encodes pigment epithelium-derived factor (PEDF), a ubiquitously expressed protein originally described for its neurotrophic and antiangiogenic properties. In this study, we characterized the skeletal phenotype of a mouse with targeted disruption of Pedf. In normal mouse bone, Pedf was localized to osteoblasts and osteocytes. Micro-computed tomography (µCT) and quantitative bone histomorphometry in femurs of mature Pedf null mutants revealed reduced trabecular bone volume and the accumulation of unmineralized bone matrix. Fourier transform infrared microscopy (FTIR) indicated an increased mineral:matrix ratio in mutant bones, which were more brittle than controls. In vitro, osteoblasts from Pedf null mice exhibited enhanced mineral deposition as assessed by Alizarin Red staining and an increased mineral:matrix determined by FTIR analysis of calcified nodules. The findings in this mouse model mimic the principal structural and biochemical features of bone observed in humans with OI type VI and consequently provide a useful model with which to further investigate the role of PEDF in this bone disorder.
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Affiliation(s)
- Rosalind Bogan
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, MD, USA
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49
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Riddle RC, Diegel CR, Leslie JM, Van Koevering KK, Faugere MC, Clemens TL, Williams BO. Lrp5 and Lrp6 exert overlapping functions in osteoblasts during postnatal bone acquisition. PLoS One 2013; 8:e63323. [PMID: 23675479 PMCID: PMC3651091 DOI: 10.1371/journal.pone.0063323] [Citation(s) in RCA: 91] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 04/02/2013] [Indexed: 11/18/2022] Open
Abstract
The canonical Wnt signaling pathway is critical for skeletal development and maintenance, but the precise roles of the individual Wnt co-receptors, Lrp5 and Lrp6, that enable Wnt signals to be transmitted in osteoblasts remain controversial. In these studies, we used Cre-loxP recombination, in which Cre-expression is driven by the human osteocalcin promoter, to determine the individual contributions of Lrp5 and Lrp6 in postnatal bone acquisition and osteoblast function. Mice selectively lacking either Lrp5 or Lrp6 in mature osteoblasts were born at the expected Mendelian frequency but demonstrated significant reductions in whole-body bone mineral density. Bone architecture measured by microCT revealed that Lrp6 mutant mice failed to accumulate normal amounts of trabecular bone. By contrast, Lrp5 mutants had normal trabecular bone volume at 8 weeks of age, but with age, these mice also exhibited trabecular bone loss. Both mutants also exhibited significant alterations in cortical bone structure. In vitro differentiation was impaired in both Lrp5 and Lrp6 null osteoblasts as indexed by alkaline phosphatase and Alizarin red staining, but the defect was more pronounced in Lrp6 mutant cells. Mice lacking both Wnt co-receptors developed severe osteopenia similar to that observed previously in mice lacking β-catenin in osteoblasts. Likewise, calvarial cells doubly deficient for Lrp5 and Lrp6 failed to form osteoblasts when cultured in osteogenic media, but instead attained a chondrocyte-like phenotype. These results indicate that expression of both Lrp5 and Lrp6 are required within mature osteoblasts for normal postnatal bone development.
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Affiliation(s)
- Ryan C. Riddle
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Veterans Administration Medical Center, Baltimore, Maryland, United States of America
- * E-mail: (RR); (BOW)
| | - Cassandra R. Diegel
- Center for Skeletal Disease and Tumor Metastasis and Laboratory of Cell Signaling and Carcinogenesis, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Julie M. Leslie
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
| | - Kyle K. Van Koevering
- Center for Skeletal Disease and Tumor Metastasis and Laboratory of Cell Signaling and Carcinogenesis, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
| | - Marie-Claude Faugere
- Department of Medicine, University of Kentucky, Lexington, Kentucky, United States of America
| | - Thomas L. Clemens
- Department of Orthopaedic Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America
- Veterans Administration Medical Center, Baltimore, Maryland, United States of America
| | - Bart O. Williams
- Center for Skeletal Disease and Tumor Metastasis and Laboratory of Cell Signaling and Carcinogenesis, Van Andel Research Institute, Grand Rapids, Michigan, United States of America
- * E-mail: (RR); (BOW)
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Abstract
Purinergic signaling may represent an effective target in cancer therapy because the expression of purinergic receptors is altered in many forms of cancer and extracellular nucleotides modulate cancer cell growth. We examined the effect of extracellular ATP on the growth of the metastatic breast carcinoma cell line MDA-MB-435 relative to an immortalized breast epithelial cell line, hTERT-HME1. We also investigated whether the metastasis suppressor gene BRMS1 alters the sensitivity of breast cancer cells to ATP. Exposure to ATP for 24 h decreased proliferation and induced apoptosis in hTERT-HME1. However, exposure to ATP did not decrease proliferation or induce apoptosis in MDA-MD-435 cells until 48 h of exposure and only at higher doses than were effective with hTERT-HME1, suggesting MDA-MB-435 cells were resistant to the antiproliferative and apoptosis-inducing effects of ATP. Exposure to ATP for 24 h induced a decrease in proliferation of MDA-MB-435 cells expressing BRMS1, similar to hTERT-HME1, but did not induce an increase in apoptosis. MDA-MB-435 cells expressed low levels of the purinergic receptor P2Y2, as well as decreased ATP-induced cytosolic calcium mobilization, relative to hTERT-HME1. However, expressing BRMS1 in MDA-MB-435 cells restored P2Y2 levels and ATP-induced cytosolic calcium mobilization such that they were similar to hTERT-HME1. These data suggest that BRMS1 increases the sensitivity of breast cancer cells to the antiproliferative, but not apoptosis-inducing effects of ATP and that this is at least partly mediated by increased expression of the P2Y2 receptor.
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Affiliation(s)
- Yue Zhang
- Division of Musculoskeletal Sciences, Department of Orthopaedics and Rehabilitation, Penn State College of Medicine , Hershey, Pennsylvania
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