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Maurel DB, Matsumoto T, Vallejo JA, Johnson ML, Dallas SL, Kitase Y, Brotto M, Wacker MJ, Harris MA, Harris SE, Bonewald LF. Characterization of a novel murine Sost ER T2 Cre model targeting osteocytes. Bone Res 2019; 7:6. [PMID: 30820362 PMCID: PMC6382861 DOI: 10.1038/s41413-018-0037-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 09/25/2018] [Accepted: 10/19/2018] [Indexed: 12/28/2022] Open
Abstract
Transgenic mice are widely used to delete or overexpress genes in a cell specific manner to advance knowledge of bone biology, function and disease. While numerous Cre models exist to target gene recombination in osteoblasts and osteoclasts, few target osteocytes specifically, particularly mature osteocytes. Our goal was to create a spatial and temporal conditional Cre model using tamoxifen to induce Cre activity in mature osteocytes using a Bac construct containing the 5' and 3' regions of the Sost gene (Sost ERT2 Cre). Four founder lines were crossed with the Ai9 Cre reporter mice. One founder line showed high and specific activity in mature osteocytes. Bones and organs were imaged and fluorescent signal quantitated. While no activity was observed in 2 day old pups, by 2 months of age some osteocytes were positive as osteocyte Cre activity became spontaneous or 'leaky' with age. The percentage of positive osteocytes increased following tamoxifen injection, especially in males, with 43% to 95% positive cells compared to 19% to 32% in females. No signal was observed in any bone surface cell, bone marrow, nor in muscle with or without tamoxifen injection. No spontaneous signal was observed in any other organ. However, with tamoxifen injection, a few positive cells were observed in kidney, eye, lung, heart and brain. All other organs, 28 in total, were negative with tamoxifen injection. However, with age, a muscle phenotype was apparent in the Sost-ERT2 Cre mice. Therefore, although this mouse model may be useful for targeting gene deletion or expression to mature osteocytes, the muscle phenotype may restrict the use of this model to specific applications and should be considered when interpreting data.
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Affiliation(s)
- Delphine B Maurel
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA.,7Present Address: Pharmaceutical Sciences Department, Universite de Bordeaux, Bio-Tis, INSERM Unité 1026 BioTis, 146 Rue Léo Saignat, 33076 Bordeaux, France
| | - Tsutomu Matsumoto
- 2Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN USA
| | - Julian A Vallejo
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA
| | - Mark L Johnson
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA
| | - Sarah L Dallas
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA
| | - Yukiko Kitase
- 2Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN USA
| | - Marco Brotto
- 3Bone-Muscle Collaborative Sciences, College of Nursing and Health Innovation, University of Texas at Arlington, Arlington, USA
| | - Michael J Wacker
- 4Department of Biomedical Sciences, University of Missouri-Kansas City School of Medicine, Kansas City, MO USA
| | - Marie A Harris
- 5University of Texas Health Science Center, San Antonio, TX USA
| | | | - Lynda F Bonewald
- 1Department of Oral and Craniofacial Sciences, University of Missouri-Kansas City School of Dentistry, Kansas City, MO USA.,2Department of Anatomy and Cell Biology, Indiana University School of Medicine, Indianapolis, IN USA.,6Department of Orthopaedic Surgery, Indiana University School of Medicine, Indianapolis, IN USA
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Du E, Xiao L, Hurley MM. FGF23 Neutralizing Antibody Ameliorates Hypophosphatemia and Impaired FGF Receptor Signaling in Kidneys of HMWFGF2 Transgenic Mice. J Cell Physiol 2016; 232:610-616. [PMID: 27306296 DOI: 10.1002/jcp.25458] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Accepted: 06/14/2016] [Indexed: 01/15/2023]
Abstract
High molecular weight FGF2 transgenic mice (HMWTg) phenocopy the Hyp mouse, homolog of human X-linked hypophosphatemic rickets with phosphate wasting and abnormal fibroblast growth factor (FGF23), fibroblast growth factor receptor (FGFR), Klotho and mitogen activated protein kinases (MAPK) signaling in kidney. In this study, we assessed whether short-term (24 h) in vivo administration of FGF23 neutralizing antibody (FGF23Ab) could rescue hypophosphatemia and impaired FGFR signaling in kidneys of HMWTg male mice. Bone mineral density and bone mineral content in 1-month-old HMWTg mice were significantly reduced compared with Control/VectorTg mice. Serum FGF23 was significantly increased in HMWTg compared with VectorTg. Serum phosphate was significantly reduced in HMWTg and was rescued by FGF23Ab. Serum parathyroid hormone (PTH) was significantly increased in HMWTg but was not reduced by FGF23Ab. 1, 25(OH)2 D was inappropriately normal in serum of HMWTg and was significantly increased in both Vector and HMWTg by FGF23Ab. Analysis of HMWTg kidneys revealed significantly increased mRNA expression of the FGF23 co-receptor Klotho, transcription factor mRNAs for early growth response-1 transcription factor (Egr-1), and c-fos were all significantly decreased by FGF23Ab. A significant reduction in the phosphate transporter Npt2a mRNA was also observed in HMWTg kidneys, which was increased by FGF23Ab. FGF23Ab reduced p-FGFR1, p-FGFR3, KLOTHO, p-ERK1/2, C-FOS, and increased NPT2A protein in HMWTg kidneys. We conclude that FGF23 blockade rescued hypophosphatemia by regulating FGF23/FGFR downstream signaling in HMWTg kidneys. Furthermore, HMWFGF2 isoforms regulate PTH expression independent of FGF23/FGFR signaling. J. Cell. Physiol. 232: 610-616, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- E Du
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut
| | - L Xiao
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut
| | - M M Hurley
- Department of Medicine, University of Connecticut Health Center, Farmington, Connecticut
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Ornitz DM, Itoh N. The Fibroblast Growth Factor signaling pathway. WILEY INTERDISCIPLINARY REVIEWS. DEVELOPMENTAL BIOLOGY 2015; 4:215-66. [PMID: 25772309 PMCID: PMC4393358 DOI: 10.1002/wdev.176] [Citation(s) in RCA: 1321] [Impact Index Per Article: 146.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/23/2014] [Accepted: 01/08/2015] [Indexed: 12/13/2022]
Abstract
The signaling component of the mammalian Fibroblast Growth Factor (FGF) family is comprised of eighteen secreted proteins that interact with four signaling tyrosine kinase FGF receptors (FGFRs). Interaction of FGF ligands with their signaling receptors is regulated by protein or proteoglycan cofactors and by extracellular binding proteins. Activated FGFRs phosphorylate specific tyrosine residues that mediate interaction with cytosolic adaptor proteins and the RAS-MAPK, PI3K-AKT, PLCγ, and STAT intracellular signaling pathways. Four structurally related intracellular non-signaling FGFs interact with and regulate the family of voltage gated sodium channels. Members of the FGF family function in the earliest stages of embryonic development and during organogenesis to maintain progenitor cells and mediate their growth, differentiation, survival, and patterning. FGFs also have roles in adult tissues where they mediate metabolic functions, tissue repair, and regeneration, often by reactivating developmental signaling pathways. Consistent with the presence of FGFs in almost all tissues and organs, aberrant activity of the pathway is associated with developmental defects that disrupt organogenesis, impair the response to injury, and result in metabolic disorders, and cancer. For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- David M Ornitz
- Department of Developmental Biology, Washington University School of MedicineSt. Louis, MO, USA
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Correspondence to:
| | - Nobuyuki Itoh
- Graduate School of Pharmaceutical Sciences, Kyoto UniversitySakyo, Kyoto, Japan
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A unified model for bone-renal mineral and energy metabolism. Curr Opin Pharmacol 2015; 22:64-71. [PMID: 25880364 DOI: 10.1016/j.coph.2015.03.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2015] [Revised: 03/27/2015] [Accepted: 03/30/2015] [Indexed: 01/09/2023]
Abstract
The beginning of the millennium saw the discovery of a new bone-matrix protein, Matrix Extracellular PhosphoglycoprotEin (MEPE) and an associated C-terminal motif called ASARM. This motif and other distinguishing features occur in a group of proteins called SIBLINGs. These proteins include dentin matrix protein 1 (DMP1), osteopontin, dentin-sialophosphoprotein (DSPP), statherin, bone sialoprotein (BSP) and MEPE. MEPE, DMP1 and ASARM-motifs regulate expression of a phosphate regulating cytokine FGF23. Further, a trimeric interaction between phosphate regulating endopeptidase homolog X-linked (PHEX), DMP1, and α5β3-integrin that occurs on the plasma-membrane of the osteocyte mediates FGF23 regulation (FAP pathway). ASARM-peptides competitively inhibit the trimeric complex and increase FGF23. A second pathway involves specialized structures, matrix vesicles pathway (MVP). This review will discuss the FAP and MVP pathways and present a unified model for mineral and energy metabolism.
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Xie Y, Zhou S, Chen H, Du X, Chen L. Recent research on the growth plate: Advances in fibroblast growth factor signaling in growth plate development and disorders. J Mol Endocrinol 2014; 53:T11-34. [PMID: 25114206 DOI: 10.1530/jme-14-0012] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Skeletons are formed through two distinct developmental actions, intramembranous ossification and endochondral ossification. During embryonic development, most bone is formed by endochondral ossification. The growth plate is the developmental center for endochondral ossification. Multiple signaling pathways participate in the regulation of endochondral ossification. Fibroblast growth factor (FGF)/FGF receptor (FGFR) signaling has been found to play a vital role in the development and maintenance of growth plates. Missense mutations in FGFs and FGFRs can cause multiple genetic skeletal diseases with disordered endochondral ossification. Clarifying the molecular mechanisms of FGFs/FGFRs signaling in skeletal development and genetic skeletal diseases will have implications for the development of therapies for FGF-signaling-related skeletal dysplasias and growth plate injuries. In this review, we summarize the recent advances in elucidating the role of FGFs/FGFRs signaling in growth plate development, genetic skeletal disorders, and the promising therapies for those genetic skeletal diseases resulting from FGFs/FGFRs dysfunction. Finally, we also examine the potential important research in this field in the future.
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Affiliation(s)
- Yangli Xie
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Siru Zhou
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Hangang Chen
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Xiaolan Du
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
| | - Lin Chen
- Department of Rehabilitation MedicineCenter of Bone Metabolism and Repair, Trauma Center, State Key Laboratory of Trauma, Burns and Combined Injury, Institute of Surgery Research, Daping Hospital, Third Military Medical University, Chongqing 400042, China
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Levin A, Rigatto C, Barrett B, Madore F, Muirhead N, Holmes D, Clase CM, Tang M, Djurdjev O, Agharazii M, de Québec; LD, Akbarii A, Barré P, Barrett B, Clase C, Cooper S, Forzley B, Cournoyer S, Dionne J, Donnelly S, Hemmelgarn B, Keown P, Zalunardo, N, Levin A, Lok C, Madore F, Moist L, Muirhead N, Nathoo B, Parmar M, Leblanc M, Rigatto C, Soroka S, Thanamayooran S, Tobe S, Yeates K. Biomarkers of inflammation, fibrosis, cardiac stretch and injury predict death but not renal replacement therapy at 1 year in a Canadian chronic kidney disease cohort. Nephrol Dial Transplant 2013; 29:1037-47. [DOI: 10.1093/ndt/gft479] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Adeera Levin
- University of British Columbia, Vancouver, Canada
| | | | | | | | | | | | | | - Mila Tang
- St. Paul's Hospital, Vancouver, Canada
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Huang X, Jiang Y, Xia W. FGF23 and Phosphate Wasting Disorders. Bone Res 2013; 1:120-32. [PMID: 26273497 DOI: 10.4248/br201302002] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 04/25/2013] [Indexed: 11/10/2022] Open
Abstract
A decade ago, only two hormones, parathyroid hormone and 1,25(OH)2D, were widely recognized to directly affect phosphate homeostasis. Since the discovery of fibroblast growth factor 23 (FGF23) in 2000 (1), our understanding of the mechanisms of phosphate homeostasis and of bone mineralization has grown exponentially. FGF23 is the link between intestine, bone, and kidney together in phosphate regulation. However, we still do not know the complex mechanism of phosphate homeostasis and bone mineralization. The physiological role of FGF23 is to regulate serum phosphate. Secreted mainly by osteocytes and osteoblasts in the skeleton (2,3), it modulates kidney handling of phosphate reabsorption and calcitriol production. Genetic and acquired abnormalities in FGF23 structure and metabolism cause conditions of either hyper-FGF23 or hypo-FGF23. Hyper-FGF23 is related to hypophosphatemia, while hypo-FGF23 is related to hyperphosphatemia. Both hyper-FGF23 and hypo-FGF23 are detrimental to humans. In this review, we will discuss the pathophysiology of FGF23 and hyper-FGF23 related renal phosphate wasting disorders (4).
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Affiliation(s)
- Xianglan Huang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Yan Jiang
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
| | - Weibo Xia
- Department of Endocrinology, Key Laboratory of Endocrinology, Ministry of Health, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences , Shuaifuyuan No. 1, Wangfujing, Dongcheng District, Beijing 100730, China
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Abstract
PURPOSE OF REVIEW Description of the recent advances on the regulation of phosphate metabolism, gene mutations, and new approaches to treatment in patients with hypophosphatemic rickets. RECENT FINDINGS Fibroblast growth factor 23 (FGF23) overproduction may be a primary cause of hypophosphatemic rickets. Inactivating mutations of phosphate-regulating gene with homologies to endopeptidases on the X chromosome, dentin matrix acidic phosphoprotein 1, and ectonucleotide pyrophosphatase/phosphodiesterase 1 are associated with X-linked hypophosphatemic rickets, autosomal recessive hypophosphatemic rickets 1, and autosomal recessive hypophosphatemic rickets 2, respectively. Activating mutations of FGF23 gene is the cause of autosomal dominant hypophosphatemic rickets. Iron deficiency may affect autosomal dominant hypophosphatemic rickets phenotype by regulating FGF23 production.Current treatment with activated vitamin D metabolites and oral inorganic phosphate salts may partially correct skeletal lesions and linear growth in patients with hypophosphatemic rickets. However, some patients have poor improvement by the current treatment. SUMMARY Identification of the causative mutation in patients with hypophosphatemic rickets may be useful to confirm the diagnosis and probably for prognosis. Inhibition of FGF23 overproduction by anti-FGF23 neutralizing antibodies could be a future approach for treatment of patients with FGF23-dependent hypophosphatemic rickets.
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Affiliation(s)
- Giampiero I Baroncelli
- Pediatric Unit I, Department of Obstetrics, Gynecology and Pediatrics, University-Hospital, Pisa, Italy.
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