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Dudakovic A, Jerez S, Deosthale PJ, Denbeigh JM, Paradise CR, Gluscevic M, Zan P, Begun DL, Camilleri ET, Pichurin O, Khani F, Thaler R, Lian JB, Stein GS, Westendorf JJ, Plotkin LI, van Wijnen AJ. MicroRNA-101a enhances trabecular bone accrual in male mice. Sci Rep 2022; 12:13361. [PMID: 35922466 PMCID: PMC9349183 DOI: 10.1038/s41598-022-17579-0] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/27/2022] [Indexed: 11/09/2022] Open
Abstract
High-throughput microRNA sequencing was performed during differentiation of MC3T3-E1 osteoblasts to develop working hypotheses for specific microRNAs that control osteogenesis. The expression data show that miR-101a, which targets the mRNAs for the epigenetic enzyme Ezh2 and many other proteins, is highly upregulated during osteoblast differentiation and robustly expressed in mouse calvaria. Transient elevation of miR-101a suppresses Ezh2 levels, reduces tri-methylation of lysine 27 in histone 3 (H3K27me3; a heterochromatic mark catalyzed by Ezh2), and accelerates mineralization of MC3T3-E1 osteoblasts. We also examined skeletal phenotypes of an inducible miR-101a transgene under direct control of doxycycline administration. Experimental controls and mir-101a over-expressing mice were exposed to doxycycline in utero and postnatally (up to 8 weeks of age) to maximize penetrance of skeletal phenotypes. Male mice that over-express miR-101a have increased total body weight and longer femora. MicroCT analysis indicate that these mice have increased trabecular bone volume fraction, trabecular number and trabecular thickness with reduced trabecular spacing as compared to controls. Histomorphometric analysis demonstrates a significant reduction in osteoid volume to bone volume and osteoid surface to bone surface. Remarkably, while female mice also exhibit a significant increase in bone length, no significant changes were noted by microCT (trabecular bone parameters) and histomorphometry (osteoid parameters). Hence, miR-101a upregulation during osteoblast maturation and the concomitant reduction in Ezh2 mediated H3K27me3 levels may contribute to the enhanced trabecular bone parameters in male mice. However, the sex-specific effect of miR-101a indicates that more intricate epigenetic mechanisms mediate physiological control of bone formation and homeostasis.
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Affiliation(s)
- Amel Dudakovic
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA.
- Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, USA.
| | - Sofia Jerez
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Padmini J Deosthale
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Janet M Denbeigh
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Christopher R Paradise
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, MN, USA
- Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Martina Gluscevic
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
- Center for Regenerative Medicine, Mayo Clinic, Rochester, MN, USA
| | - Pengfei Zan
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
- Department of Orthopedic Surgery, School of Medicine, Second Affiliated Hospital of Zhejiang University, Hangzhou, China
- Department of Orthopedic Surgery, School of Medicine, Shanghai Tenth People's Hospital Affiliated to Tongji University, Shanghai, China
| | - Dana L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | | | - Oksana Pichurin
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Farzaneh Khani
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Roman Thaler
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Jane B Lian
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Gary S Stein
- Department of Biochemistry, University of Vermont, Burlington, VT, USA
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
- Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - Lilian I Plotkin
- Department of Anatomy, Cell Biology & Physiology, Indiana University School of Medicine, Indianapolis, IN, USA.
- Indiana Center for Musculoskeletal Health, Indiana University School of Medicine, Indianapolis, IN, USA.
- Richard L Roudebush VA Medical Center, Indianapolis, IN, USA.
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Molstad DHH, Mattson AM, Begun DL, Westendorf JJ, Bradley EW. Hdac3 regulates bone modeling by suppressing osteoclast responsiveness to RANKL. J Biol Chem 2021; 295:17713-17723. [PMID: 33454009 DOI: 10.1074/jbc.ra120.013573] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 09/30/2020] [Indexed: 11/06/2022] Open
Abstract
Hdac3 is a lysine deacetylase that removes acetyl groups from histones and additional proteins. Although Hdac3 functions within mesenchymal lineage skeletal cells are defined, little is known about Hdac3 activities in bone-resorbing osteoclasts. In this study we conditionally deleted Hdac3 within Ctsk-expressing cells and examined the effects on bone modeling and osteoclast differentiation in mice. Hdac3 deficiency reduced femur and tibia periosteal circumference and increased cortical periosteal osteoclast number. Trabecular bone was likewise reduced and was accompanied by increased osteoclast number per trabecular bone surface. We previously showed that Hdac3 deacetylates the p65 subunit of the NF-κB transcriptional complex to decrease DNA-binding and transcriptional activity. Hdac3-deficient osteoclasts demonstrate increased K310 NF-κB acetylation and NF-κB transcriptional activity. Hdac3-deficient osteoclast lineage cells were hyper-responsive to RANKL and showed elevated ex vivo osteoclast number and size and enhanced bone resorption in pit formation assays. Osteoclast-directed Hdac3 deficiency decreased cortical and trabecular bone mass parameters, suggesting that Hdac3 regulates coupling of bone resorption and bone formation. We surveyed a panel of osteoclast-derived coupling factors and found that Hdac3 suppression diminished sphingosine-1-phosphate production. Osteoclast-derived sphingosine-1-phosphate acts in paracrine to promote bone mineralization. Mineralization of WT bone marrow stromal cells cultured with conditioned medium from Hdac3-deficient osteoclasts was markedly reduced. Expression of alkaline phosphatase, type 1a1 collagen, and osteocalcin was also suppressed, but no change in Runx2 expression was observed. Our results demonstrate that Hdac3 controls bone modeling by suppressing osteoclast lineage cell responsiveness to RANKL and coupling to bone formation.
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Affiliation(s)
- David H H Molstad
- Department of Orthopedics, University of Minnesota, Minneapolis, Minnesota, USA
| | - Anna M Mattson
- Departments of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Dana L Begun
- Departments of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Jennifer J Westendorf
- Departments of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA; Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Elizabeth W Bradley
- Department of Orthopedics, University of Minnesota, Minneapolis, Minnesota, USA; Stem Cell Institute, University of Minnesota, Minneapolis, Minnesota, USA.
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3
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Dudakovic A, Samsonraj RM, Paradise CR, Galeano-Garces C, Mol MO, Galeano-Garces D, Zan P, Galvan ML, Hevesi M, Pichurin O, Thaler R, Begun DL, Kloen P, Karperien M, Larson AN, Westendorf JJ, Cool SM, van Wijnen AJ. Inhibition of the epigenetic suppressor EZH2 primes osteogenic differentiation mediated by BMP2. J Biol Chem 2020; 295:7877-7893. [PMID: 32332097 DOI: 10.1074/jbc.ra119.011685] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [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: 10/29/2019] [Revised: 04/22/2020] [Indexed: 12/17/2022] Open
Abstract
Bone-stimulatory therapeutics include bone morphogenetic proteins (e.g. BMP2), parathyroid hormone, and antibody-based suppression of WNT antagonists. Inhibition of the epigenetic enzyme enhancer of zeste homolog 2 (EZH2) is both bone anabolic and osteoprotective. EZH2 inhibition stimulates key components of bone-stimulatory signaling pathways, including the BMP2 signaling cascade. Because of high costs and adverse effects associated with BMP2 use, here we investigated whether BMP2 dosing can be reduced by co-treatment with EZH2 inhibitors. Co-administration of BMP2 with the EZH2 inhibitor GSK126 enhanced differentiation of murine (MC3T3) osteoblasts, reflected by increased alkaline phosphatase activity, Alizarin Red staining, and expression of bone-related marker genes (e.g. Bglap and Phospho1). Strikingly, co-treatment with BMP2 (10 ng/ml) and GSK126 (5 μm) was synergistic and was as effective as 50 ng/ml BMP2 at inducing MC3T3 osteoblastogenesis. Similarly, the BMP2-GSK126 co-treatment stimulated osteogenic differentiation of human bone marrow-derived mesenchymal stem/stromal cells, reflected by induction of key osteogenic markers (e.g. Osterix/SP7 and IBSP). A combination of BMP2 (300 ng local) and GSK126 (5 μg local and 5 days of 50 mg/kg systemic) yielded more consistent bone healing than single treatments with either compound in a mouse calvarial critical-sized defect model according to results from μCT, histomorphometry, and surgical grading of qualitative X-rays. We conclude that EZH2 inhibition facilitates BMP2-mediated induction of osteogenic differentiation of progenitor cells and maturation of committed osteoblasts. We propose that epigenetic priming, coupled with bone anabolic agents, enhances osteogenesis and could be leveraged in therapeutic strategies to improve bone mass.
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Affiliation(s)
- Amel Dudakovic
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.,Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Christopher R Paradise
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota, USA.,Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Merel O Mol
- Department of Orthopedic Surgery, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | | | - Pengfei Zan
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.,Department of Orthopedic Surgery, School of Medicine, Second Affiliated Hospital of Zhejiang University, Hangzhou, China.,Department of Orthopedic Surgery, School of Medicine, Shanghai Tenth People's Hospital Affiliated to Tongji University, Shanghai, China
| | - M Lizeth Galvan
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Mario Hevesi
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Oksana Pichurin
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Roman Thaler
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Dana L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Peter Kloen
- Department of Orthopedic Surgery, Amsterdam University Medical Center, Amsterdam, The Netherlands
| | - Marcel Karperien
- Department of Developmental BioEngineering, University of Twente, Enschede, The Netherlands
| | - A Noelle Larson
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA.,Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
| | - Simon M Cool
- Glycotherapeutics Group, Institute of Medical Biology, Agency for Science, Technology and Research (A*STAR), Singapore.,Department of Orthopaedic Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Andre J van Wijnen
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA .,Department of Biochemistry & Molecular Biology, Mayo Clinic, Rochester, Minnesota, USA
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Pierce JL, Ding KH, Xu J, Sharma AK, Yu K, Del Mazo Arbona N, Rodriguez-Santos Z, Bernard P, Bollag WB, Johnson MH, Hamrick MW, Begun DL, Shi XM, Isales CM, McGee-Lawrence ME. The glucocorticoid receptor in osteoprogenitors regulates bone mass and marrow fat. J Endocrinol 2019; 243:JOE-19-0230.R1. [PMID: 31370004 PMCID: PMC6938567 DOI: 10.1530/joe-19-0230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 07/31/2019] [Indexed: 12/18/2022]
Abstract
Excess fat within bone marrow is associated with lower bone density. Metabolic stressors such as chronic caloric restriction (CR) can exacerbate marrow adiposity, and increased glucocorticoid signaling and adrenergic signaling are implicated in this phenotype. The current study tested the role of glucocorticoid signaling in CR-induced stress by conditionally deleting the glucocorticoid receptor (GR) in bone marrow osteoprogenitors (Osx1-Cre) of mice subjected to CR and ad libitum diets. Conditional knockout of the GR (GR-CKO) reduced cortical and trabecular bone mass as compared to wildtype (WT) mice under both ad libitum and CR conditions. No interaction was detected between genotype and diet, suggesting that the GR is not required for CR-induced skeletal changes. The lower bone mass in GR-CKO mice, and the further suppression of bone by CR, resulted from suppressed bone formation. Interestingly, treatment with the -adrenergic receptor antagonist propranolol mildly but selectively improved metrics of cortical bone mass in GR-CKO mice during CR, suggesting interaction between adrenergic and glucocorticoid signaling pathways that affects cortical bone. GR-CKO mice dramatically increased marrow fat under both ad libitum and CR-fed conditions, and surprisingly propranolol treatment was unable to rescue CR-induced marrow fat in either WT or GR-CKO mice. Additionally, serum corticosterone levels were selectively elevated in GR-CKO mice with CR, suggesting the possibility of bone-hypothalamus-pituitary-adrenal crosstalk during metabolic stress. This work highlights the complexities of glucocorticoid and β-adrenergic signaling in stress-induced changes in bone mass, and the importance of GR function in suppressing marrow adipogenesis while maintaining healthy bone mass.
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Affiliation(s)
- Jessica L Pierce
- J Pierce, Cellular Biology and Anatomy, Augusta University, Augusta, United States
| | - Ke-Hong Ding
- K Ding, Neuroscience and Regenerative Medicine, Augusta University, Augusta, United States
| | - Jianrui Xu
- J Xu, Neuroscience and Regenerative Medicine, Augusta University, Augusta, United States
| | - Anuj K Sharma
- A Sharma, Cellular Biology and Anatomy, Augusta University, Augusta, United States
| | - Kanglun Yu
- K Yu, Cellular Biology and Anatomy, Augusta University, Augusta, United States
| | | | | | - Paul Bernard
- P Bernard, Pediatric Endocrine Specialists of Georgia, Pediatric Endocrine Specialists of Georgia, Duluth, United States
| | - Wendy B Bollag
- W Bollag, Department of Physiology, Medical College of Georgia, Augusta, GA 30912, United States
| | - Maribeth H Johnson
- M Johnson, Neuroscience and Regenerative Medicine, Augusta University, Augusta, United States
| | - Mark W Hamrick
- M Hamrick, Cellular Biology and Anatomy, Augusta University, Augusta, United States
| | - Dana L Begun
- D Begun, Department of Orthopedic Surgery, Mayo Clinic, Rochester, United States
| | - Xing M Shi
- X Ming Shi, Neuroscience and Regenerative Medicine, Augusta University, Augusta, United States
| | - Carlos M Isales
- C Isales, Neuroscience and Regenerative Medicine, Augusta University, Augusta, 30912, United States
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Mattson AM, Begun DL, Molstad DHH, Meyer MA, Oursler MJ, Westendorf JJ, Bradley EW. Deficiency in the phosphatase PHLPP1 suppresses osteoclast-mediated bone resorption and enhances bone formation in mice. J Biol Chem 2019; 294:11772-11784. [PMID: 31189651 DOI: 10.1074/jbc.ra119.007660] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [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: 01/23/2019] [Revised: 05/24/2019] [Indexed: 12/21/2022] Open
Abstract
Enhanced osteoclast-mediated bone resorption and diminished formation may promote bone loss. Pleckstrin homology (PH) domain and leucine-rich repeat protein phosphatase 1 (Phlpp1) regulates protein kinase C (PKC) and other proteins in the control of bone mass. Germline Phlpp1 deficiency reduces bone volume, but the mechanisms remain unknown. Here, we found that conditional Phlpp1 deletion in murine osteoclasts increases their numbers, but also enhances bone mass. Despite elevating osteoclasts, Phlpp1 deficiency did not increase serum markers of bone resorption, but elevated serum markers of bone formation. These results suggest that Phlpp1 suppresses osteoclast formation and production of paracrine factors controlling osteoblast activity. Phlpp1 deficiency elevated osteoclast numbers and size in ex vivo osteoclastogenesis assays, accompanied by enhanced expression of proto-oncogene C-Fms (C-Fms) and hyper-responsiveness to macrophage colony-stimulating factor (M-CSF) in bone marrow macrophages. Although Phlpp1 deficiency increased TRAP+ cell numbers, it suppressed actin-ring formation and bone resorption in these assays. We observed that Phlpp1 deficiency increases activity of PKCζ, a PKC isoform controlling cell polarity, and that addition of a PKCζ pseudosubstrate restores osteoclastogenesis and bone resorption of Phlpp1-deficient osteoclasts. Moreover, Phlpp1 deficiency increased expression of the bone-coupling factor collagen triple helix repeat-containing 1 (Cthrc1). Conditioned growth medium derived from Phlpp1-deficient osteoclasts enhanced mineralization of ex vivo osteoblast cultures, an effect that was abrogated by Cthrc1 knockdown. In summary, Phlpp1 critically regulates osteoclast numbers, and Phlpp1 deficiency enhances bone mass despite higher osteoclast numbers because it apparently disrupts PKCζ activity, cell polarity, and bone resorption and increases secretion of bone-forming Cthrc1.
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Affiliation(s)
- Anna M Mattson
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Dana L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - David H H Molstad
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Margaret A Meyer
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901
| | - Merry Jo Oursler
- Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55901.,Endocrine Research Unit, Mayo Clinic, Rochester, Minnesota 55901.,Kogod Center on Aging, Mayo Clinic, Rochester, Minnesota 55901
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901.,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55901
| | - Elizabeth W Bradley
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55901 .,Department of Biomedical Engineering and Physiology, Mayo Clinic, Rochester, Minnesota 55901
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Abstract
Bone is a complex endocrine organ that facilitates structural support, protection to vital organs, sites for hematopoiesis, and calcium homeostasis. The bone marrow microenvironment is a heterogeneous niche consisting of multipotent musculoskeletal and hematopoietic progenitors and their derivative terminal cell types. Amongst these progenitors, bone marrow mesenchymal stem/stromal cells (BMSCs) may differentiate into osteogenic, adipogenic, myogenic, and chondrogenic lineages to support musculoskeletal development as well as tissue homeostasis, regeneration and repair during adulthood. With age, the commitment of BMSCs to osteogenesis slows, bone formation decreases, fracture risk rises, and marrow adiposity increases. An unresolved question is whether osteogenesis and adipogenesis are co-regulated in the bone marrow. Osteogenesis and adipogenesis are controlled by specific signaling mechanisms, circulating cytokines, and transcription factors such as Runx2 and Pparγ, respectively. One hypothesis is that adipogenesis is the default pathway if osteogenic stimuli are absent. However, recent work revealed that Runx2 and Osx1-expressing preosteoblasts form lipid droplets under pathological and aging conditions. Histone deacetylase 3 (Hdac3) and other epigenetic regulators suppress lipid storage in preosteoblasts and/or control marrow adiposity. Establishing a better understanding of fat storage in bone marrow cells, as well as the osteoblast-adipocyte relationship within the bone marrow niche is necessary to understand the mechanisms underlying disease- and aging-related marrow fat storage and may lead to the development of new therapeutic targets for "fatty bone" and osteoporosis.
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Affiliation(s)
- J L Pierce
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA
| | - D L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - J J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, USA
| | - M E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta University, Augusta, GA, USA; Department of Orthopaedic Surgery, Augusta University, Augusta, GA, USA.
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7
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Dudakovic A, Camilleri ET, Paradise CR, Samsonraj RM, Gluscevic M, Paggi CA, Begun DL, Khani F, Pichurin O, Ahmed FS, Elsayed R, Elsalanty M, McGee-Lawrence ME, Karperien M, Riester SM, Thaler R, Westendorf JJ, van Wijnen AJ. Enhancer of zeste homolog 2 ( Ezh2) controls bone formation and cell cycle progression during osteogenesis in mice. J Biol Chem 2018; 293:12894-12907. [PMID: 29899112 DOI: 10.1074/jbc.ra118.002983] [Citation(s) in RCA: 59] [Impact Index Per Article: 9.8] [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: 03/19/2018] [Revised: 06/12/2018] [Indexed: 12/25/2022] Open
Abstract
Epigenetic mechanisms control skeletal development and osteoblast differentiation. Pharmacological inhibition of the histone 3 Lys-27 (H3K27) methyltransferase enhancer of zeste homolog 2 (EZH2) in WT mice enhances osteogenesis and stimulates bone formation. However, conditional genetic loss of Ezh2 early in the mesenchymal lineage (i.e. through excision via Prrx1 promoter-driven Cre) causes skeletal abnormalities due to patterning defects. Here, we addressed the key question of whether Ezh2 controls osteoblastogenesis at later developmental stages beyond patterning. We show that Ezh2 loss in committed pre-osteoblasts by Cre expression via the osterix/Sp7 promoter yields phenotypically normal mice. These Ezh2 conditional knock-out mice (Ezh2 cKO) have normal skull bones, clavicles, and long bones but exhibit increased bone marrow adiposity and reduced male body weight. Remarkably, in vivo Ezh2 loss results in a low trabecular bone phenotype in young mice as measured by micro-computed tomography and histomorphometry. Thus, Ezh2 affects bone formation stage-dependently. We further show that Ezh2 loss in bone marrow-derived mesenchymal cells suppresses osteogenic differentiation and impedes cell cycle progression as reflected by decreased metabolic activity, reduced cell numbers, and changes in cell cycle distribution and in expression of cell cycle markers. RNA-Seq analysis of Ezh2 cKO calvaria revealed that the cyclin-dependent kinase inhibitor Cdkn2a is the most prominent cell cycle target of Ezh2 Hence, genetic loss of Ezh2 in mouse pre-osteoblasts inhibits osteogenesis in part by inducing cell cycle changes. Our results suggest that Ezh2 serves a bifunctional role during bone formation by suppressing osteogenic lineage commitment while simultaneously facilitating proliferative expansion of osteoprogenitor cells.
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Affiliation(s)
- Amel Dudakovic
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Emily T Camilleri
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - Christopher R Paradise
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota 55905; Center for Regenerative Medicine, Mayo Clinic, Rochester, Minnesota 55905
| | | | - Martina Gluscevic
- Mayo Clinic Graduate School of Biomedical Sciences, Mayo Clinic, Rochester, Minnesota 55905
| | - Carlo Alberto Paggi
- Department of Developmental BioEngineering, University of Twente, 7522 NB Enschede, Netherlands
| | - Dana L Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - Farzaneh Khani
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - Oksana Pichurin
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - Farah S Ahmed
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - Ranya Elsayed
- Department of Oral Biology, Augusta University, Augusta, Georgia 30912
| | | | - Meghan E McGee-Lawrence
- Department of Cellular Biology and Anatomy, Augusta University, Augusta, Georgia 30912; Department of Orthopedic Surgery, Medical College of Georgia, Augusta University, Augusta, Georgia 30912
| | - Marcel Karperien
- Department of Developmental BioEngineering, University of Twente, 7522 NB Enschede, Netherlands
| | - Scott M Riester
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - Roman Thaler
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905
| | - Jennifer J Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905
| | - Andre J van Wijnen
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota 55905; Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, Minnesota 55905.
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8
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Hwang SM, Feigenson M, Begun DL, Shull LC, Culley KL, Otero M, Goldring MB, Ta LE, Kakar S, Bradley EW, Westendorf JJ. Phlpp inhibitors block pain and cartilage degradation associated with osteoarthritis. J Orthop Res 2018; 36:1487-1497. [PMID: 29068480 PMCID: PMC5985222 DOI: 10.1002/jor.23781] [Citation(s) in RCA: 17] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2017] [Accepted: 10/21/2017] [Indexed: 02/04/2023]
Abstract
Phlpp protein phosphatases are abnormally abundant within human osteoarthritic articular chondrocytes and may contribute to the development of osteoarthritis. Mice lacking Phlpp1 were previously shown to be resistant to post-traumatic osteoarthritis. Here a small molecule with therapeutic properties that inhibits Phlpp1 and Phlpp2 was tested for its ability to slow post-traumatic OA in mice and to stimulate anabolic pathways in human articular cartilage from OA joints. PTOA was induced in male C57Bl/6 mice by surgically destabilizing the meniscus. Seven weeks after surgery, mice received a single intra-articular injection of the Phlpp inhibitor NSC117079 or saline. Mechanical allodynia was measured with von Frey assays, mobility was tracked in an open field system, and cartilage damage was assessed histologically. A single intra-articular injection of the Phlpp inhibitor NSC117079 attenuated mechanical allodynia and slowed articular cartilage degradation in joints with a destabilized meniscus. Animals treated with the Phlpp inhibitor 7 weeks after injury maintained normal activity levels, while those in the control group traveled shorter distances and were less active 3 months after the joint injury. NSC117079 also increased production of cartilage extracellular matrix components (glycosaminoglycans and aggrecan) in over 90% of human articular cartilage explants from OA patients and increased phosphorylation of Phlpp1 substrates (AKT2, ERK1/2, and PKC) in human articular chondrocytes. Our results indicate that Phlpp inhibitor NSC117079 is a novel osteoarthritis disease modifying drug candidate that may have palliative affects. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1487-1497, 2018.
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Affiliation(s)
- Soyun M. Hwang
- Mayo Clinic School of Medicine, Mayo Clinic, Rochester, MN, 55905 USA
| | - Marina Feigenson
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, 55905 USA
| | - Dana L. Begun
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, 55905 USA
| | | | - Kirsty L. Culley
- HSS Research Institute, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY 10021, USA
| | - Miguel Otero
- HSS Research Institute, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY 10021, USA
| | - Mary B. Goldring
- HSS Research Institute, Hospital for Special Surgery, Weill Cornell Medical College, New York, NY 10021, USA
| | - Lauren E. Ta
- Department of Neurology, Mayo Clinic, Rochester, MN, 55905 USA
| | - Sanjeev Kakar
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, 55905 USA
| | - Elizabeth W. Bradley
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, 55905 USA,Co-corresponding authors. ,
| | - Jennifer J. Westendorf
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, 55905 USA,Department of Biochemistry and Molecular Biology, Mayo Clinic, Rochester, MN, 55905 USA,Co-corresponding authors. ,
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9
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Soves CP, Miller JD, Begun DL, Taichman RS, Hankenson KD, Goldstein SA. Megakaryocytes are mechanically responsive and influence osteoblast proliferation and differentiation. Bone 2014; 66:111-20. [PMID: 24882736 PMCID: PMC4125454 DOI: 10.1016/j.bone.2014.05.015] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 05/12/2014] [Accepted: 05/23/2014] [Indexed: 12/21/2022]
Abstract
Maintenance of bone mass and geometry is influenced by mechanical stimuli. Paradigms suggest that osteocytes embedded within the mineralized matrix and osteoblasts on the bone surfaces are the primary responders to physical forces. However, other cells within the bone marrow cavity, such as megakaryocytes (MKs), are also subject to mechanical forces. Recent studies have highlighted the potent effects of MKs on osteoblast proliferation as well as bone formation in vivo. We hypothesize that MKs are capable of responding to physical forces and that the interactions between these cells and osteoblasts can be influenced by mechanical stimulation. In this study, we demonstrate that two MK cell lines respond to fluid shear stress in culture. Furthermore, using laser capture microdissection, we isolated MKs from histologic sections of murine tibiae that were exposed to compressive loads in vivo. C-fos, a transcription factor shown to be upregulated in response to load in various tissue types, was increased in MKs from loaded relative to non-loaded limbs at a level comparable to that of osteocytes from the same limbs. We also developed a co-culture system to address whether mechanical stimulation of MKs in culture would impact osteoblast proliferation and differentiation. The presence of MKs in co-culture, but not conditioned media, had dramatic effects on proliferation of preosteoblast MC3T3-E1 cells in culture. Our data suggests a minimal decrease in proliferation as well as an increase in mineralization capacity of osteoblasts co-cultured with MKs exposed to shear compared to co-cultures with unstimulated MKs.
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Affiliation(s)
- Constance P Soves
- Orthopaedic Research Laboratories, University of Michigan, Room 2003 Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Joshua D Miller
- Orthopaedic Research Laboratories, University of Michigan, Room 2003 Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Dana L Begun
- Orthopaedic Research Laboratories, University of Michigan, Room 2003 Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Russell S Taichman
- Department of Periodontics and Oral Medicine, University of Michigan School of Dentistry, 1011 North University Ave., Ann Arbor, MI 48109, USA
| | - Kurt D Hankenson
- Department of Clinical Studies-New Bolton Center, School of Veterinary Medicine, University of Pennsylvania, Room 145 Myrin Bldg, Kennett Square PA; Department of Orthopaedic Surgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia PA
| | - Steven A Goldstein
- Orthopaedic Research Laboratories, University of Michigan, Room 2003 Biomedical Sciences Research Building, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA.
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10
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Meganck JA, Begun DL, McElderry JD, Swick A, Kozloff KM, Goldstein SA, Morris MD, Marini JC, Caird MS. Fracture healing with alendronate treatment in the Brtl/+ mouse model of osteogenesis imperfecta. Bone 2013; 56:204-12. [PMID: 23774443 PMCID: PMC3999166 DOI: 10.1016/j.bone.2013.06.003] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2013] [Revised: 05/31/2013] [Accepted: 06/01/2013] [Indexed: 11/26/2022]
Abstract
Osteogenesis imperfecta (OI) is a heritable bone dysplasia characterized by increased skeletal fragility. Patients are often treated with bisphosphonates to attempt to reduce fracture risk. However, bisphosphonates reside in the skeleton for many years and long-term administration may impact bone material quality. Acutely, there is concern about risk of non-union of fractures that occur near the time of bisphosphonate administration. This study investigated the effect of alendronate, a potent aminobisphosphonate, on fracture healing. Using the Brtl/+ murine model of type IV OI, tibial fractures were generated in 8-week-old mice that were untreated, treated with alendronate before fracture, or treated before and after fracture. After 2, 3, or 5 weeks of healing, tibiae were assessed using microcomputed tomography (μCT), torsion testing, quantitative histomorphometry, and Raman microspectroscopy. There were no morphologic, biomechanical or histomorphometric differences in callus between untreated mice and mice that received alendronate before fracture. Alendronate treatment before fracture did not cause a significant increase in cartilage retention in fracture callus. Both Brtl/+ and WT mice that received alendronate before and after fracture had increases in the callus volume, bone volume fraction and torque at failure after 5 weeks of healing. Raman microspectroscopy results did not show any effects of alendronate in wild-type mice, but calluses from Brtl/+ mice treated with alendronate during healing had a decreased mineral-to-matrix ratio, decreased crystallinity and an increased carbonate-to-phosphate ratio. Treatment with alendronate altered the dynamics of healing by preventing callus volume decreases later in the healing process. Fracture healing in Brtl/+ untreated animals was not significantly different from animals in which alendronate was halted at the time of fracture.
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Affiliation(s)
- J A Meganck
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA.
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11
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Li Y, Ge C, Long JP, Begun DL, Rodriguez JA, Goldstein SA, Franceschi RT. Biomechanical stimulation of osteoblast gene expression requires phosphorylation of the RUNX2 transcription factor. J Bone Miner Res 2012; 27:1263-74. [PMID: 22337141 PMCID: PMC3532028 DOI: 10.1002/jbmr.1574] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Bone can adapt its structure in response to mechanical stimuli. At the cellular level, this involves changes in chromatin organization, gene expression, and differentiation, but the underlying mechanisms are poorly understood. Here we report on the involvement of RUNX2, a bone-related transcription factor, in this process. Fluid flow shear stress loading of preosteoblasts stimulated translocation of extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) to the nucleus where it phosphorylated RUNX2 on the chromatin of target genes, and increased histone acetylation and gene expression. MAPK signaling and two RUNX2 phosphoacceptor sites, S301 and S319, were critical for this response. Similarly, in vivo loading of mouse ulnae dramatically increased ERK and RUNX2 phosphorylation as well as expression of osteoblast-related genes. These findings establish ERK/MAPK-mediated phosphorylation of RUNX2 as a critical step in the response of preosteoblasts to dynamic loading and define a novel mechanism to explain how mechanical signals induce gene expression in bone.
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Affiliation(s)
- Yan Li
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Chunxi Ge
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Jason P Long
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Dana L Begun
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Jose A Rodriguez
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
| | - Steven A Goldstein
- Orthopaedic Research Laboratories, Department of Orthopaedic Surgery, University of Michigan, Ann Arbor, MI, USA
| | - Renny T Franceschi
- Department of Periodontics and Oral Medicine, School of Dentistry, University of Michigan, Ann Arbor, MI, USA
- Department of Biological Chemistry, School of Medicine, University of Michigan, Ann Arbor, MI, USA
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12
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Wood AR, Bebej RM, Manz CL, Begun DL, Gingerich PD. Postcranial Functional Morphology of Hyracotherium (Equidae, Perissodactyla) and Locomotion in the Earliest Horses. J MAMM EVOL 2010. [DOI: 10.1007/s10914-010-9145-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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13
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Weaver AS, Su YP, Begun DL, Miller JD, Alford AI, Goldstein SA. The effects of axial displacement on fracture callus morphology and MSC homing depend on the timing of application. Bone 2010; 47:41-8. [PMID: 20303421 PMCID: PMC2892246 DOI: 10.1016/j.bone.2010.03.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2009] [Revised: 03/10/2010] [Accepted: 03/10/2010] [Indexed: 10/19/2022]
Abstract
The local mechanical environment and the availability of mesenchymal stem cells (MSC) have both been shown to be important factors in bone fracture healing. This study was designed to investigate how the timing of an applied axial displacement across a healing fracture affects callus properties as well as the migration of systemically introduced MSC. Bilateral osteotomies were created in male, Sprague-Dawley rats. Exogenous MSC were injected via the tail vein, and a controlled micro-motion was applied to one defect starting 0, 3, 10, or 24 days after surgery. The results showed that fractures stimulated 10 days after surgery had more mineral, less cartilage, and greater mechanical properties at 48 days than other groups. Populations of MSC were found in osteotomies 48 days after surgery, with the exception of the group that was stimulated 10 days after surgery. These results demonstrate that the timing of mechanical stimulation affects the physical properties of the callus and the migration of MSC to the fracture site.
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Affiliation(s)
- Aaron S Weaver
- Orthopaedic Research Laboratories, University of Michigan, Ann Arbor, MI 48109, USA
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Affiliation(s)
- S B Trachman
- Department of Psychiatry and Behavioral Sciences, George Washington University Medical Center, Washington, DC
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