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Hoogduijn MJ, Rakonczay Z, Genever PG. The Effects of Anticholinergic Insecticides on Human Mesenchymal Stem Cells. Toxicol Sci 2006; 94:342-50. [PMID: 16960032 DOI: 10.1093/toxsci/kfl101] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Mesenchymal stem cells (MSCs) are located primarily in the bone marrow and are characterized by their capacity to differentiate into mesenchymal lineages such as bone, fat, and cartilage in response to appropriate signals. Several signaling mechanisms act to control MSC survival, proliferation, and differentiation, and failure or disruption of these signaling pathways can lead to degenerative disease or neoplasia. Organophosphate (OP) and carbamate pesticides, which are used in large amounts in agriculture to control insects, are designed to disrupt acetylcholine signaling by inhibiting the enzyme acetylcholinesterase (AChE). Effects of OP and carbamate pesticides on the human central nervous system have been well documented. However, AChE is broadly distributed, and the effects of anticholinergic insecticides on nonnervous tissue have received little attention. In the present study we found that human MSCs express AChE, which makes these cells potential targets for AChE inhibiting agents. We therefore examined the effects of an OP pesticide, chlorpyrifos, and a carbamate, carbofuran, on MSC characteristics. It was found that micromolar concentrations of these anticholinergic insecticides had no effect on MSC survival or proliferation but limited MSC differentiation capacity by inhibiting osteogenic differentiation. These results demonstrate that exposure to micromolar concentrations of OP and carbamate pesticides may affect tissue turnover and pathophysiology by interfering with MSC regulation.
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Affiliation(s)
- Martin J Hoogduijn
- Biomedical Tissue Research Group, Department of Biology, University of York, Heslington, York, YO10 5YW, United Kingdom
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Lee JS, Thomas DM, Gutierrez G, Carty SA, Yanagawa SI, Hinds PW. HES1 cooperates with pRb to activate RUNX2-dependent transcription. J Bone Miner Res 2006; 21:921-33. [PMID: 16753023 DOI: 10.1359/jbmr.060303] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED The retinoblastoma protein, pRb, can activate the transcription factor RUNX2, an essential regulator of osteogenic differentiation, but the mechanism of this activation is unknown. Here we studied the interaction of pRb and RUNX2 with HES1, previously reported to augment RUNX2 activity. PRb can act to promote RUNX2/HES1 association with concomitant promoter occupancy and transcriptional activation in bone cells. INTRODUCTION RUNX2 (also known as OSF2/CBFA1) is a transcription factor required for osteoblast differentiation and bone formation. We have reported that RUNX2 can associate with the retinoblastoma protein pRb, a common tumor suppressor in bone, and the resultant complex can bind and activate transcription from bone-specific promoters. This activity of the pRb/RUNX2 complex may thus link differentiation control with tumor suppressor activity. However, the mechanism through which pRb can activate RUNX2 is unknown. HES1 is a reported co-activator of RUNX2 that shares a binding site on RUNX2 with pRb. Thus, we have tested the cooperativity among these factors in activating transcription from bone specific promoters. MATERIALS AND METHODS Coimmunoprecipitation, chromatin immunoprecipitation, and EMSA experiments were used to study the interaction of RUNX2, HES1, and pRb in cell lysates and on DNA. Transcriptional reporter assays were used to analyze the activity of RUNX2 in the presence and absence of HES1 and pRb. RESULTS We showed that pRb can associate with HES1, a previously described RUNX2 interactor that can itself augment RUNX2-dependent transcription. The association of HES1 with RUNX2 is augmented by pRb. Furthermore, both pRb and HES1 increase the amount of RUNX2 bound to promoter sites in vivo, pRb and HES1 synergistically activate a RUNX2-dependent reporter gene, and depletion of HES1 reduces RUNX2/pRb activity. CONCLUSIONS These data indicate that pRb acts as a RUNX2 co-activator at least in part by recruiting HES1 into the pRb/RUNX2 complex and further elucidate a novel role for pRb as a transcriptional co-activator in osteogenesis.
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Affiliation(s)
- Jong-Seo Lee
- Department of Pathology, Harvard Medical School Boston, Massachusetts, USA
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Kim CS, Sohn SH, Jeon SK, Kim KN, Ryu JJ, Kim MK. Effect of various implant coatings on biological responses in MG63 using cDNA microarray. J Oral Rehabil 2006; 33:368-79. [PMID: 16629896 DOI: 10.1111/j.1365-2842.2005.01553.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
During the process of bone formation, titanium (Ti) surface is an important factor in the modulation of osteoblastic function. This study was conducted in order to determine the effects of different Ti surfaces on the biological responses of a human osteoblast-like cell line (MG63). MG63 cells were cultured on smooth (S), sandblasted large-grit and acid etching (SLA), hydroxyapatite (HA), hydroxyfluoride (HF), titanium nitrate (TIN), and diamond-like carbon (DLC) Ti. The morphology of these cells were assessed by SEM. The cDNAs prepared from the total RNAs of the MG63 were hybridized into a human cDNA microarray (1152 elements). The appearances of the surfaces observed by SEM were different on each of the six dental substrate types. The SLA and HA surfaces were determined to be rougher than the others. MG63 cells cultured on SLA and HA exhibited cell-matrix interactions. In the expression of genes involved in osseointegration, several genes, including bone morphogenetic protein, cadherin, integrin, and insulin-like growth factors, were upregulated on the different surfaces. Several genes, including fibroblast growth factor receptor 4, Bcl 2-related protein, and collagen, were downregulated on the different surfaces. The attachment and expression of key osteogenic regulatory genes were enhanced by the surface roughness of the dental materials used.
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Affiliation(s)
- C-S Kim
- Department of Dentistry, College of Medicine, Korea University, Seoul, South Korea
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Ostroukhova M, Qi Z, Oriss TB, Dixon-McCarthy B, Ray P, Ray A. Treg-mediated immunosuppression involves activation of the Notch-HES1 axis by membrane-bound TGF-beta. J Clin Invest 2006; 116:996-1004. [PMID: 16543950 PMCID: PMC1401482 DOI: 10.1172/jci26490] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Accepted: 01/24/2006] [Indexed: 12/14/2022] Open
Abstract
Studies in humans and mice show an important role for Tregs in the control of immunological disorders. The mechanisms underlying the immunosuppressive functions of Tregs are not well understood. Here, we show that CD4+ T cells expressing Foxp3 and membrane-bound TGF-beta (TGF-beta(m+)Foxp3+), previously shown to be immunosuppressive in both allergic and autoimmune diseases, activate the Notch1-hairy and enhancer of split 1 (Notch1-HES1) axis in target cells. Soluble TGF-beta and cells secreting similar levels of soluble TGF-beta were unable to trigger Notch1 activation. Inhibition of Notch1 activation in vivo reversed the immunosuppressive functions of TGF-beta(m+)Foxp3+ cells, resulting in severe allergic airway inflammation. Integration of the TGF-beta and Notch1 pathways may be an important mechanism for the maintenance of immune homeostasis in the periphery.
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Affiliation(s)
- Marina Ostroukhova
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, and
Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Zengbiao Qi
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, and
Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Timothy B. Oriss
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, and
Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Barbara Dixon-McCarthy
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, and
Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Prabir Ray
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, and
Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
| | - Anuradha Ray
- Department of Medicine, Division of Pulmonary, Allergy, and Critical Care Medicine, and
Department of Immunology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA
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van Someren EP, Vaes BLT, Steegenga WT, Sijbers AM, Dechering KJ, Reinders MJT. Least absolute regression network analysis of the murine osteoblast differentiation network. ACTA ACUST UNITED AC 2005; 22:477-84. [PMID: 16332709 DOI: 10.1093/bioinformatics/bti816] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
MOTIVATION We propose a reverse engineering scheme to discover genetic regulation from genome-wide transcription data that monitors the dynamic transcriptional response after a change in cellular environment. The interaction network is estimated by solving a linear model using simultaneous shrinking of the least absolute weights and the prediction error. RESULTS The proposed scheme has been applied to the murine C2C12 cell-line stimulated to undergo osteoblast differentiation. Results show that our method discovers genetic interactions that display significant enrichment of co-citation in literature. More detailed study showed that the inferred network exhibits properties and hypotheses that are consistent with current biological knowledge.
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Affiliation(s)
- E P van Someren
- Department of Mediametics, Delft University of Technology, 2600 GA Delft, The Netherlands.
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Abstract
Members of the Notch family of transmembrane receptors play an important role in cell fate determination. Over the past decade, a role for Notch in the pathogenesis of hematologic and solid malignancies has become apparent. Numerous cellular functions and microenvironmental cues associated with tumorigenesis are modulated by Notch signaling, including proliferation, apoptosis, adhesion, epithelial-to-mesenchymal transition, and angiogenesis. It is becoming increasingly evident that Notch signaling can be both oncogenic and tumor suppressive. This review highlights recent findings regarding the molecular and functional aspects of Notch-mediated neoplastic transformation. In addition, cellular mechanisms that potentially explain the complex role of Notch in tumorigenesis are discussed.
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Affiliation(s)
- Kevin G Leong
- Department of Medical Biophysics, British Columbia Cancer Agency, Vancouver, BC, Canada
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Schaller S, Henriksen K, Hoegh-Andersen P, Søndergaard BC, Sumer EU, Tanko LB, Qvist P, Karsdal MA. In Vitro, Ex Vivo, andIn VivoMethodological Approaches for Studying Therapeutic Targets of Osteoporosis and Degenerative Joint Diseases: How Biomarkers Can Assist? Assay Drug Dev Technol 2005; 3:553-80. [PMID: 16305312 DOI: 10.1089/adt.2005.3.553] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although our approach to the clinical management of osteoporosis (OP) and degenerative joint diseases (DJD)-major causes of disability and morbidity in the elderly-has greatly advanced in the past decades, curative treatments that could bring ultimate solutions have yet to be found or developed. Effective and timely development of candidate drugs is a critical function of the availability of sensitive and accurate methodological arsenal enabling the recognition and quantification of pharmacodynamic effects. The established concept that both OP and DJD arise from an imbalance in processes of tissue formation and degradation draws attention to need of establishing in vitro, ex vivo, and in vivo experimental settings, which allow obtaining insights into the mechanisms driving increased bone and cartilage degradation at cellular, organ, and organism levels. When addressing changes in bone or cartilage turnover at the organ or organism level, monitoring tools adequately reflecting the outcome of tissue homeostasis become particularly critical. In this context, bioassays targeting the quantification of various degradation and formation products of bone and cartilage matrix elements represent a useful approach. In this review, a comprehensive overview of widely used and recently established in vitro, ex vivo, and in vivo set-ups is provided, which in many cases effectively take advantage of the potentials of biomarkers. In addition to describing and discussing the advantages and limitations of each assay and their methods of evaluation, we added experimental and clinical data illustrating the utility of biomarkers for these methodological approaches.
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Matsuda Y, Wakamatsu Y, Kohyama J, Okano H, Fukuda K, Yasugi S. Notch signaling functions as a binary switch for the determination of glandular and luminal fates of endodermal epithelium during chicken stomach development. Development 2005; 132:2783-93. [PMID: 15930109 DOI: 10.1242/dev.01853] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During development of the chicken proventriculus (glandular stomach), gut endoderm differentiates into glandular and luminal epithelium. We found that Delta1-expressing cells, undifferentiated cells and Notch-activated cells colocalize within the endodermal epithelium during early gland formation. Inhibition of Notch signaling using Numb or dominant-negative form of Su(H) resulted in a luminal differentiation, while forced activation of Notch signaling promoted the specification of immature glandular cells, but prevented the subsequent differentiation and the invagination of the glands. These results suggest that Delta1-mediated Notch signaling among endodermal cells functions as a binary switch for determination of glandular and luminal fates, and regulates patterned differentiation of glands in the chicken proventriculus.
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Affiliation(s)
- Yoshimasa Matsuda
- Department of Biological Sciences, Graduate School of Science, Tokyo Metropolitan University, 1-1 Minamiohsawa, Hachiohji, Tokyo 192-0397, Japan
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Abe T, Furue M, Kondow A, Matsuzaki K, Asashima M. Notch signaling modulates the nuclear localization of carboxy-terminal-phosphorylated smad2 and controls the competence of ectodermal cells for activin A. Mech Dev 2005; 122:671-80. [PMID: 15817224 DOI: 10.1016/j.mod.2004.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Revised: 12/11/2004] [Accepted: 12/11/2004] [Indexed: 11/18/2022]
Abstract
Loss of mesodermal competence (LMC) during Xenopus development is a well known but little understood phenomenon that prospective ectodermal cells (animal caps) lose their competence for inductive signals, such as activin A, to induce mesodermal genes and tissues after the start of gastrulation. Notch signaling can delay the onset of LMC for activin A in animal caps [Coffman, C.R., Skoglund, P., Harris, W.A., Kintner, C.R., 1993. Expression of an extracellular deletion of Xotch diverts cell fate in Xenopus embryos. Cell 73, 659-671], although the mechanism by which this modulation occurs remains unknown. Here, we show that Notch signaling also delays the onset of LMC in whole embryos, as it did in animal caps. To better understand this effect and the mechanism of LMC itself, we investigated at which step of activin signal transduction pathway the Notch signaling act to affect the timing of the LMC. In our system, ALK4 (activin type I receptor) maintained the ability to phosphorylate the C-terminal region of smad2 upon activin A stimulus after the onset of LMC in both control- and Notch-activated animal caps. However, C-terminal-phosphorylated smad2 could bind to smad4 and accumulate in the nucleus only in Notch-activated animal caps. We conclude that LMC was induced because C-terminal-phosphorylated smad2 lost its ability to bind to smad4, and consequently could not accumulate in the nucleus. Notch signal activation restored the ability of C-terminal-phosphorylated smad2 to bind to smad4, resulting in a delay in the onset of LMC.
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Affiliation(s)
- Takanori Abe
- Department of Biological Science, Graduate School of Science, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
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60
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Nobta M, Tsukazaki T, Shibata Y, Xin C, Moriishi T, Sakano S, Shindo H, Yamaguchi A. Critical regulation of bone morphogenetic protein-induced osteoblastic differentiation by Delta1/Jagged1-activated Notch1 signaling. J Biol Chem 2005; 280:15842-8. [PMID: 15695512 DOI: 10.1074/jbc.m412891200] [Citation(s) in RCA: 158] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Functional involvement of the Notch pathway in osteoblastic differentiation has been previously investigated using the truncated intracellular domain, which mimics Notch signaling by interacting with the DNA-binding protein CBF-1. However, it is unclear whether Notch ligands Delta1 and Jagged1 also induce an identical cellular response in osteoblastic differentiation. We have shown that both Delta1 and Jagged1 were expressed concomitantly with Notch1 in maturating osteoblastic cells during bone regeneration and that overexpressed and immobilized recombinant Delta1 and Jagged1 alone did not alter the differentiated state of MC3T3-E1 and C2C12 cells. However, they augmented bone morphogenetic protein-2 (BMP2)-induced alkaline phosphatase activity and the expression of several differentiation markers, except for osteocalcin, and ultimately enhanced calcified nodule and in vivo ectopic bone formation of MC3T3-E1. In addition, both ligands transmitted signal through the CBF-1-dependent pathway and stimulated the expression of HES-1, a direct target of Notch pathway. To test the necessity of Notch signaling in BMP2-induced differentiation, Notch signaling was inhibited by the dominant negative extracellular domain of Notch1, specific inhibitor, or small interference RNA. These treatments decreased alkaline phosphatase activity as well as the expression of other differentiation markers and inhibited the promoter activity of Id-1, a target gene of the BMP pathway. These results indicate the functional redundancy between Delta1 and Jagged1 in osteoblastic differentiation whereby Delta1/Jagged1-activated Notch1 enhances BMP2-induced differentiation through the identical signaling pathway. Furthermore, our data also suggest that functional Notch signaling is essential not only for BMP2-induced osteoblast differentiation but also for BMP signaling itself.
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Affiliation(s)
- Masuhiro Nobta
- Divisions of Orthopaedic Pathomechanism, Department of Developmental and Reconstructive Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki 852-8588, Japan
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