51
|
De novo characterization of the antler tip of Chinese Sika deer transcriptome and analysis of gene expression related to rapid growth. Mol Cell Biochem 2011; 364:93-100. [DOI: 10.1007/s11010-011-1209-3] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 12/15/2011] [Indexed: 01/26/2023]
|
52
|
Dingwall M, Marchildon F, Gunanayagam A, Louis CS, Wiper-Bergeron N. Retinoic acid-induced Smad3 expression is required for the induction of osteoblastogenesis of mesenchymal stem cells. Differentiation 2011; 82:57-65. [PMID: 21612856 DOI: 10.1016/j.diff.2011.05.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2010] [Revised: 04/28/2011] [Accepted: 05/09/2011] [Indexed: 12/18/2022]
Abstract
Mesenchymal stem cells are pluripotent precursor cells that can differentiate into osteoblasts, adipocytes, chondrocytes and myocytes. Despite their important therapeutic potential little is known about the transcriptional cascades that govern lineage decisions in these cells. Treatment of C3H10T1/2 mouse mesenchymal stem cells with retinoic acid (RA) inhibits adipogenesis and enhances osteoblastogenesis. In particular, RA treatment stimulates the expression of the osteoblast master regulator, runt-related transcription factor 2 (Runx2), whose expression is necessary for the formation of bone. We have shown previously in mesenchymal stem cells that RA acts to stimulate osteoblastogenesis by interfering with the actions of the bzip transcription factor CCAAT/Enhancer Binding Protein beta (C/EBPβ), where it binds to a negative regulatory element within the Runx2 promoter and inhibits its expression. Herein we show that Smad3, whose expression is stimulated by RA, relays the effects of RA on differentiation by initiating the displacement of C/EBPβ from the Runx2 promoter. In addition to stimulating Smad3 expression, RA also stimulated the nuclear localization of this factor, such that in the absence of RA, ectopic Smad3 was unable to drive osteoblastogenesis. While not sufficient to promote osteoblastogenesis, knockdown of Smad3 using a specific shRNA prevented the RA-mediated stimulation of differentiation and displacement of C/EBPβ from the Runx2 P1 promoter. Taken together, these data indicate that Smad3 is an important mediator of RA activity during mesenchymal stem cell differentiation and is necessary for the stimulation of osteoblastogenesis.
Collapse
Affiliation(s)
- Molly Dingwall
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada K1H 8M5
| | | | | | | | | |
Collapse
|
53
|
Coordinate activation of inflammatory gene networks, alveolar destruction and neonatal death in AKNA deficient mice. Cell Res 2011; 21:1564-77. [PMID: 21606955 DOI: 10.1038/cr.2011.84] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Gene expression can be regulated by chromatin modifiers, transcription factors and proteins that modulate DNA architecture. Among the latter, AT-hook transcription factors have emerged as multifaceted regulators that can activate or repress broad A/T-rich gene networks. Thus, alterations of AT-hook genes could affect the transcription of multiple genes causing global cell dysfunction. Here we report that targeted deletions of mouse AKNA, a hypothetical AT-hook-like transcription factor, sensitize mice to pathogen-induced inflammation and cause sudden neonatal death. Compared with wild-type littermates, AKNA KO mice appeared weak, failed to thrive and most died by postnatal day 10. Systemic inflammation, predominantly in the lungs, was accompanied by enhanced leukocyte infiltration and alveolar destruction. Cytologic, immunohistochemical and molecular analyses revealed CD11b(+)Gr1(+) neutrophils as major tissue infiltrators, neutrophilic granule protein, cathelin-related antimicrobial peptide and S100A8/9 as neutrophil-specific chemoattracting factors, interleukin-1β and interferon-γ as proinflammatory mediators, and matrix metalloprotease 9 as a plausible proteolytic trigger of alveolar damage. AKNA KO bone marrow transplants in wild-type recipients reproduced the severe pathogen-induced reactions and confirmed the involvement of neutrophils in acute inflammation. Moreover, promoter/reporter experiments showed that AKNA could act as a gene repressor. Our results support the concept of coordinated pathway-specific gene regulation functions modulating the intensity of inflammatory responses, reveal neutrophils as prominent mediators of acute inflammation and suggest mechanisms underlying the triggering of acute and potentially fatal immune reactions.
Collapse
|
54
|
Arvidson K, Abdallah BM, Applegate LA, Baldini N, Cenni E, Gomez-Barrena E, Granchi D, Kassem M, Konttinen YT, Mustafa K, Pioletti DP, Sillat T, Finne-Wistrand A. Bone regeneration and stem cells. J Cell Mol Med 2011; 15:718-46. [PMID: 21129153 PMCID: PMC3922662 DOI: 10.1111/j.1582-4934.2010.01224.x] [Citation(s) in RCA: 238] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Accepted: 11/02/2010] [Indexed: 12/16/2022] Open
Abstract
This invited review covers research areas of central importance for orthopaedic and maxillofacial bone tissue repair, including normal fracture healing and healing problems, biomaterial scaffolds for tissue engineering, mesenchymal and foetal stem cells, effects of sex steroids on mesenchymal stem cells, use of platelet-rich plasma for tissue repair, osteogenesis and its molecular markers. A variety of cells in addition to stem cells, as well as advances in materials science to meet specific requirements for bone and soft tissue regeneration by addition of bioactive molecules, are discussed.
Collapse
Affiliation(s)
- K Arvidson
- Department of Clinical Dentistry, Center for Clinical Resarch, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
55
|
Miclea RL, van der Horst G, Robanus-Maandag EC, Löwik CWGM, Oostdijk W, Wit JM, Karperien M. Apc bridges Wnt/β-catenin and BMP signaling during osteoblast differentiation of KS483 cells. Exp Cell Res 2011; 317:1411-21. [PMID: 21402068 DOI: 10.1016/j.yexcr.2011.03.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2010] [Revised: 02/27/2011] [Accepted: 03/07/2011] [Indexed: 12/23/2022]
Abstract
The canonical Wnt signaling pathway influences the differentiation of mesenchymal cell lineages in a quantitative and qualitative fashion depending on the dose of β-catenin signaling. Adenomatous polyposis coli (Apc) is the critical intracellular regulator of β-catenin turnover. To better understand the molecular mechanisms underlying the role of Apc in regulating the differentiation capacity of skeletal progenitor cells, we have knocked down Apc in the murine mesenchymal stem cell-like KS483 cells by stable expression of Apc-specific small interfering RNA. In routine culture, KSFrt-Apc(si) cells displayed a mesenchymal-like spindle shape morphology, exhibited markedly decreased proliferation and increased apoptosis. Apc knockdown resulted in upregulation of the Wnt/β-catenin and the BMP/Smad signaling pathways, but osteogenic differentiation was completely inhibited. This effect could be rescued by adding high concentrations of BMP-7 to the differentiation medium. Furthermore, KSFrt-Apc(si) cells showed no potential to differentiate into chondrocytes or adipocytes. These results demonstrate that Apc is essential for the proliferation, survival and differentiation of KS483 cells. Apc knockdown blocks the osteogenic differentiation of skeletal progenitor cells, a process that can be overruled by high BMP signaling.
Collapse
Affiliation(s)
- Razvan L Miclea
- Department of Pediatrics, Leiden University Medical Centre, Leiden, the Netherlands.
| | | | | | | | | | | | | |
Collapse
|
56
|
Zhang Y, Su J, Yu J, Bu X, Ren T, Liu X, Yao L. An essential role of discoidin domain receptor 2 (DDR2) in osteoblast differentiation and chondrocyte maturation via modulation of Runx2 activation. J Bone Miner Res 2011; 26:604-17. [PMID: 20734453 DOI: 10.1002/jbmr.225] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Discoidin domain receptor 2 (DDR2) belongs to receptor tyrosine kinase (RTK) family and is activated by collagen binding. Although the bone defects in Ddr2 null mice have been reported for a decade, the molecular mechanism remains unclear. This study sought to investigate the function and detailed mechanism of DDR2 in osteogenic and chondrogenic differentiation. Herein we found that in preosteoblastic cells, DDR2 activation was enhanced by osteogenic induction but was not paralleled with the alteration of DDR2 expression. Under differentiated condition, downregulation of endogenous DDR2 through specific shRNA dramatically repressed osteoblastic marker gene expression and osteogenic differentiation. Enforced expression of constitutively activated DDR2 increased the expression of bone markers in both undifferentiated and differentiated osteoblasts. Importantly, molecular evidence showed that DDR2 regulated the transactivity of Runx2, a master transcription factor involved in skeletal development, by modulating its phosphorylation. Analysis of candidate protein kinases indicated that extracellular signal-regulated kinase (ERK) activation is responsive to DDR2 signaling and involved in DDR2 regulation of Runx2 phosphorylation and transcriptional activity. Notably, a gain-of-function mutant of Runx2 with enhanced ERK-independent phosphorylation rescued the impaired osteogenic phenotypes observed in Ddr2-silenced cells, whereas a Runx2 mutant devoid of phosphorylation regulation by ERK inhibited DDR2 induction of osteogenesis. In addition, DDR2 facilitated Runx2 transactivation and type X collagen expression in hypertrophic chondrocytes. Thus this study reveals for the first time that DDR2 plays an essential role in osteoblast and chondrocyte differentiation. The mechanism disclosure may provide therapeutic targets for human genetic disorders caused by DDR2 deficiency.
Collapse
Affiliation(s)
- Yan Zhang
- Department of Biochemistry and Molecular Biology, State Key Laboratory of Cancer Biology, The Fourth Military Medical University, Xi'an, People's Republic of China
| | | | | | | | | | | | | |
Collapse
|
57
|
Hesse E, Saito H, Kiviranta R, Correa D, Yamana K, Neff L, Toben D, Duda G, Atfi A, Geoffroy V, Horne WC, Baron R. Zfp521 controls bone mass by HDAC3-dependent attenuation of Runx2 activity. ACTA ACUST UNITED AC 2010; 191:1271-83. [PMID: 21173110 PMCID: PMC3010073 DOI: 10.1083/jcb.201009107] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Runx2 is indispensable for osteoblast lineage commitment and early differentiation but also blocks osteoblast maturation, thereby causing bone loss in Runx2 transgenic mice. Zinc finger protein 521 (Zfp521) antagonizes Runx2 in vivo. Eliminating one Zfp521 allele mitigates the cleidocranial dysplasia-like phenotype of newborn Runx2(+/-) mice, whereas overexpressing Zfp521 exacerbates it. Overexpressing Zfp521 also reverses the severe osteopenia of adult Runx2 transgenic mice. Zfp521 binds to both Runx2 and histone deacetylase 3 (HDAC3), promotes their association, and antagonizes Runx2 transcriptional activity in an HDAC3-dependent manner. Mutating the Zfp521 zinc finger domains 6 and 26 reduces the binding of Zfp521 to Runx2 and inhibition of Runx2 activity. These data provide evidence that Zfp521 antagonizes Runx2 in vivo and thereby regulates two stages of osteoblast development, early during mesenchymal cell lineage commitment and later during osteoblast maturation. Thus, the balance and molecular interplay between Zfp521 and Runx2 contribute to the control of osteoblast differentiation, skeletal development, and bone homeostasis.
Collapse
Affiliation(s)
- Eric Hesse
- Department of Medicine, Harvard Medical School, Harvard School of Dental Medicine, Harvard University, Boston, MA 02115, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
58
|
Abstract
Inflammation perturbs normal bone homeostasis and is known to induce bone loss, as it promotes both local cartilage degradation and local and systemic bone destruction by osteoclasts, as well as inhibits bone formation by osteoblasts. Thus, not surprisingly, inflammatory autoimmune diseases often lead to local and/or general bone loss. However, the mechanisms that target the bone in autoimmune disease are complex and diverse, as they range from a direct attack on the bone and cartilage by the immune cells to indirect consequences of disturbances of the systemic control of bone remodeling. This Review discusses current understanding of the mechanisms of autoimmune-mediated bone loss in view of new insight from two new fields of research: osteoimmunology, which analyzes the direct effect of immune cells on bone, and the integrative metabolism approach, which established the existence of neuroendocrine loops that regulate bone remodeling.
Collapse
Affiliation(s)
- Georg Schett
- Department of Internal Medicine 3, Rheumatology and Immunology, University of Erlangen-Nuremberg, Krankenhausstraβe 12, D-91054 Erlangen, Germany
| | | |
Collapse
|
59
|
Lin KL, Chou CH, Hsieh SC, Hwa SY, Lee MT, Wang FF. Transcriptional upregulation of DDR2 by ATF4 facilitates osteoblastic differentiation through p38 MAPK-mediated Runx2 activation. J Bone Miner Res 2010; 25:2489-503. [PMID: 20564243 DOI: 10.1002/jbmr.159] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Deficiency of the collagen receptor discoidin domain receptor tyrosine kinase (DDR2) in mice and humans results in dwarfism and short limbs, of which the mechanism remains unknown. Here we report that DDR2 is a key regulator of osteoblast differentiation. DDR2 mRNA expression was increased at an early stage of induced osteoblast differentiation. In the subchondral bone of human osteoarthritic knee, DDR2 was detected in osteoblastic cells. In mouse embryos, DDR2 expression was found from E11 to E15, preceding osteocalcin (OCN) and coinciding with Runx2 expression. Activating transcription factor 4 (ATF4) enhanced DDR2 mRNA expression, and knockdown of ATF4 expression delayed DDR2 induction during osteoblast differentiation. A CCAAT/enhancer binding protein (C/EBP) binding site at -1150 bp in the DDR2 promoter was required for ATF4-mediated DDR2 activation. C/EBPβ bound to and cooperated with ATF4 in stimulating DDR2 transcription; accordingly, the ATF4 mutants deficient of C/EBPβ binding were incapable of transactivating DDR2. Overexpression of DDR2 increased osteoblast-specific gene expression. Conversely, knockdown of DDR2 suppressed osteogenic marker gene expression and matrix mineralization during the induced osteogenesis. The stimulation of p38 MAPK by DDR2 was required for DDR2-induced activation of Runx2 and OCN promoters. Together our findings uncover a pathway in which ATF4, by binding to C/EBPβ transcriptionally upregulates DDR2 expression, and DDR2, in turn, activates Runx2 through p38 MAPK to promote osteoblast differentiation.
Collapse
Affiliation(s)
- Kuan-Liang Lin
- Institute of Biochemistry and Molecular Biology, National Yang Ming University, Taipei, Taiwan
| | | | | | | | | | | |
Collapse
|
60
|
Abstract
Vertebrate skeletogenesis consists in elaborating an edifice of more than 200 pieces of bone and cartilage. Each skeletal piece is crafted at a distinct location in the body, is articulated with others, and reaches a specific size, shape, and tissue composition according to both species instructions and individual determinants. This complex, customized body frame fulfills multiple essential tasks. It confers morphological features, allows controlled postures and movements, protects vital organs, houses hematopoiesis, stores minerals, and adsorbs toxins. This review provides an overview of the multiple facets of this ingenious process for experts as well as nonexperts of skeletogenesis. We explain how the developing vertebrate uses both specific and ubiquitously expressed genes to generate multipotent mesenchymal cells, specify them to a skeletogenic fate, control their survival and proliferation, and direct their differentiation into cartilage, bone, and joint cells. We review milestone discoveries made toward uncovering the intricate networks of regulatory factors that are involved in these processes, with an emphasis on signaling pathways and transcription factors. We describe numerous skeletal malformation and degeneration diseases that occur in humans as a result of mutations in regulatory genes, and explain how these diseases both help and motivate us to further decipher skeletogenic processes. Upon discussing current knowledge and gaps in knowledge in the control of skeletogenesis, we highlight ultimate research goals and propose research priorities and approaches for future endeavors.
Collapse
Affiliation(s)
- Véronique Lefebvre
- Department of Cell Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | | |
Collapse
|