title: Enhancer of Zeste Homolog 2 Inhibition Stimulates Bone Formation and Mitigates Bone Loss Caused by Ovariectomy in Skeletally Mature Mice.
abstract: Perturbations in skeletal development and bone degeneration may result in reduced bone mass and quality, leading to greater fracture risk. Bone loss is mitigated by bone protective therapies, but there is a clinical need for new bone-anabolic agents. Previous work has demonstrated that Ezh2 (enhancer of zeste homolog 2), a histone 3 lysine 27 (H3K27) methyltransferase, suppressed differentiation of osteogenic progenitors. Here, we investigated whether inhibition of Ezh2 can be leveraged for bone stimulatory applications. Pharmacologic inhibition and siRNA knockdown of Ezh2 enhanced osteogenic commitment of MC3T3 preosteoblasts. Next generation RNA sequencing of mRNAs and real time quantitative PCR profiling established that Ezh2 inactivation promotes expression of bone-related gene regulators and extracellular matrix proteins. Mechanistically, enhanced gene expression was linked to decreased H3K27 trimethylation (H3K27me3) near transcriptional start sites in genome-wide sequencing of chromatin immunoprecipitations assays. Administration of an Ezh2 inhibitor modestly increases bone density parameters of adult mice. Furthermore, Ezh2 inhibition also alleviated bone loss in an estrogen-deficient mammalian model for osteoporosis. Ezh2 inhibition enhanced expression of Wnt10b and Pth1r and increased the BMP-dependent phosphorylation of Smad1/5. Thus, these data suggest that inhibition of Ezh2 promotes paracrine signaling in osteoblasts and has bone-anabolic and osteoprotective potential in adults.
authors.affiliation: From the Departments of Orthopedic Surgery.
authors.forename: Amel
authors.initials: A
authors.lastname: Dudakovic
authors.affiliation: From the Departments of Orthopedic Surgery.
authors.forename: Emily T
authors.initials: ET
authors.lastname: Camilleri
authors.affiliation: From the Departments of Orthopedic Surgery.
authors.forename: Scott M
authors.initials: SM
authors.lastname: Riester
authors.affiliation: From the Departments of Orthopedic Surgery.
authors.forename: Christopher R
authors.initials: CR
authors.lastname: Paradise
authors.affiliation: Initiative for Maximum Student Development, and.
authors.forename: Martina
authors.initials: M
authors.lastname: Gluscevic
authors.affiliation: From the Departments of Orthopedic Surgery.
authors.forename: Thomas M
authors.initials: TM
authors.lastname: O'Toole
authors.affiliation: From the Departments of Orthopedic Surgery.
authors.forename: Roman
authors.initials: R
authors.lastname: Thaler
authors.affiliation: Statistics and Informatics, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Jared M
authors.initials: JM
authors.lastname: Evans
authors.affiliation: Statistics and Informatics, Mayo Clinic, Rochester, Minnesota 55905.
authors.forename: Huihuang
authors.initials: H
authors.lastname: Yan
authors.affiliation: Biochemistry & Molecular Biology.
authors.forename: Malayannan
authors.initials: M
authors.lastname: Subramaniam
authors.affiliation: Biochemistry & Molecular Biology.
authors.forename: John R
authors.initials: JR
authors.lastname: Hawse
authors.affiliation: the Department of Biochemistry, University of Vermont Medical School, Burlington, Vermont 05405.
authors.forename: Gary S
authors.initials: GS
authors.lastname: Stein
authors.affiliation: the Centro de Investigaciones Biomedicas and FONDAP Center for Genome Regulation, Universidad Andres Bello, 837-0146 Santiago, Chile, and.
authors.forename: Martin A
authors.initials: MA
authors.lastname: Montecino
authors.affiliation: the Department of Cellular Biology and Anatomy, Georgia Regents University, Augusta, Georgia 30912.
authors.forename: Meghan E
authors.initials: ME
authors.lastname: McGee-Lawrence
authors.affiliation: From the Departments of Orthopedic Surgery,; Biochemistry & Molecular Biology.
authors.forename: Jennifer J
authors.initials: JJ
authors.lastname: Westendorf
authors.affiliation: From the Departments of Orthopedic Surgery,; Biochemistry & Molecular Biology,. Electronic address: vanwijnen.andre@mayo.edu.
authors.forename: Andre J
authors.initials: AJ
authors.lastname: van Wijnen
mesh_terms: D000818:Animals; D002460:Cell Line; D000071221:Enhancer of Zeste Homolog 2 Protein / Q000235:genetics / Q000378:metabolism*; D005260:Female; D008745:Methylation / Q000187:drug effects; D051379:Mice; D010006:Osteoblasts / Q000378:metabolism* / Q000473:pathology; D010012:Osteogenesis; D010024:Osteoporosis / Q000378:metabolism* / Q000473:pathology; D010052:Ovariectomy; D019899:Paracrine Communication; D034741:RNA, Small Interfering / Q000494:pharmacology; D044168:Receptor, Parathyroid Hormone, Type 1; D051898:Smad1 Protein / Q000235:genetics / Q000378:metabolism; D051902:Smad5 Protein / Q000235:genetics / Q000378:metabolism; D051153:Wnt Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D034741:RNA, Small Interfering; D044168:Receptor, Parathyroid Hormone, Type 1; D051898:Smad1 Protein; C497401:Smad1 protein, mouse; D051902:Smad5 Protein; C497798:Smad5 protein, mouse; D051153:Wnt Proteins; C102068:Wnt10b protein, mouse; D000071221:Enhancer of Zeste Homolog 2 Protein; C498410:Ezh2 protein, mouse
keywords: epigenetics; histone; histone methylation; methyltransferase; osteoblast; osteoporosis; skeleton