Examinando por Autor "Riester, Scott M."

Mostrando 1 - 3 de 3
  • Miniatura
    Ítem
    Enhancer of zeste homolog 2 inhibition stimulates bone formation and mitigates bone loss caused by ovariectomy in skeletally mature mice
    (American Society for Biochemistry and Molecular Biology Inc. CODEN JBCHA, 2016-11) Dudakovic, Amel; Camilleri, Emily T.; Riester, Scott M.; Paradise, Christopher R.; Gluscevic, Martina; O'Toole, Thomas M.; Thaler, Roman; Evans, Jared M.; Yan, Huihuang; Subramaniam, Malayannan; Hawse, John R.; Stein, Gary S.; Montecino, Martin A.; McGee-Lawrence, Meghan E.; Westendorf, Jennifer J.; Van Wijnen, Andre J.
    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.
  • Miniatura
    Ítem
    Epigenetic control of skeletal development by the histone methyltransferase Ezh2
    (American Society for Biochemistry and Molecular Biology Inc., 2015-12) Dudakovic, Amel; Camilleri, Emily T.; Xu, Fuhua; Riester, Scott M.; McGee-Lawrence, Meghan E.; Bradley, Elizabeth W.; Paradise, Christopher R.; Lewallen, Eric A.; Thaler, Roman; Deyle, David R.; Larson, A. Noelle; Lewallen, David G.; Dietz, Allan B.; Stein, Gary S.; Montecino, Martin A.; Westendorf, Jennifer J.; Van Wijnen, Andre J.
    Epigenetic control of gene expression is critical for normal fetal development. However, chromatin-related mechanisms that activate bone-specific programs during osteogenesis have remained underexplored. Therefore, we investigated the expression profiles of a large cohort of epigenetic regulators (>300) during osteogenic differentiation of human mesenchymal cells derived from the stromal vascular fraction of adipose tissue (AMSCs). Molecular analyses establish that the polycomb group protein EZH2 (enhancer of zeste homolog 2) is down-regulated during osteoblastic differentiation of AMSCs. Chemical inhibitor and siRNA knockdown studies show that EZH2, a histone methyltransferase that catalyzes trimethylation of histone 3 lysine 27 (H3K27me3), suppresses osteogenic differentiation. Blocking EZH2 activity promotes osteoblast differentiation and suppresses adipogenic differentiation of AMSCs. High throughput RNA sequence (mRNASeq) analysis reveals that EZH2 inhibition stimulates cell cycle inhibitory proteins and enhances the production of extracellular matrix proteins. Conditional genetic loss of Ezh2 in uncommitted mesenchymal cells (Prrx1-Cre) resultsinmultiple defectsinskeletal patterning and bone formation, including shortened forelimbs, craniosynostosis, and clinodactyly. Histological analysis and mRNASeq profiling suggest that these effects are attributable to growth plate abnormalities and premature cranial suture closure because of precocious maturation of osteoblasts. We conclude that the epigenetic activity of EZH2 is required for skeletal patterning and development, but EZH2 expression declines during terminal osteoblast differentiation and matrix production. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.
  • Miniatura
    Ítem
    Expression of the ectodomain-releasing protease ADAM17 is directly regulated by the osteosarcoma and bone-related transcription factor RUNX2
    (Wiley-Liss Inc., 2018-11) Araya, Héctor F.; Sepúlveda, Hugo; Lizama, Carlos O.; Vega, Oscar A.; Jerez, Sofía; Briceño, Pedro F.; Thaler, Romane; Riester, Scott M.; Antonelli, Marcelo; Salazar-Onfray, Flavio; Rodríguez, Juan Pablo; Moreno, Ricardo D.; Montecino, Martín; Charbonneau, Martín; Dubois, Claire M.; Stein, Gary S.; van Wijnen, Andre J.; Galindo, Mario A.
    Osteoblast differentiation is controlled by transcription factor RUNX2 which temporally activates or represses several bone-related genes, including those encoding extracellular matrix proteins or factors that control cell-cell, and cell-matrix interactions. Cell-cell communication in the many skeletal pericellular micro-niches is critical for bone development and involves paracrine secretion of growth factors and morphogens. This paracrine signaling is in part regulated by “A Disintegrin And Metalloproteinase” (ADAM) proteins. These cell membrane-associated metalloproteinases support proteolytic release (“shedding”) of protein ectodomains residing at the cell surface. We analyzed microarray and RNA-sequencing data for Adam genes and show that Adam17, Adam10, and Adam9 are stimulated during BMP2 mediated induction of osteogenic differentiation and are robustly expressed in human osteoblastic cells. ADAM17, which was initially identified as a tumor necrosis factor alpha (TNFα) converting enzyme also called (TACE), regulates TNFα-signaling pathway, which inhibits osteoblast differentiation. We demonstrate that Adam17 expression is suppressed by RUNX2 during osteoblast differentiation through the proximal Adam17 promoter region (−0.4 kb) containing two functional RUNX2 binding motifs. Adam17 downregulation during osteoblast differentiation is paralleled by increased RUNX2 expression, cytoplasmic-nuclear translocation and enhanced binding to the Adam17 proximal promoter. Forced expression of Adam17 reduces Runx2 and Alpl expression, indicating that Adam17 may negatively modulate osteoblast differentiation. These findings suggest a novel regulatory mechanism involving a reciprocal Runx2-Adam17 negative feedback loop to regulate progression through osteoblast differentiation. Our results suggest that RUNX2 may control paracrine signaling through regulation of ectodomain shedding at the cell surface of osteoblasts by directly suppressing Adam17 expression. © 2018 Wiley Periodicals, Inc.