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Rivero S, Ruiz-García A, Díaz-Guerra MJM, Laborda J, García-Ramírez JJ. Characterization of a proximal Sp1 response element in the mouse Dlk2 gene promoter. BMC Mol Biol 2011; 12:52. [PMID: 22185379 PMCID: PMC3296630 DOI: 10.1186/1471-2199-12-52] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2011] [Accepted: 12/20/2011] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND DLK2 is an EGF-like membrane protein, closely related to DLK1, which is involved in adipogenesis. Both proteins interact with the NOTCH1 receptor and are able to modulate its activation. The expression of the gene Dlk2 is coordinated with that of Dlk1 in several tissues and cell lines. Unlike Dlk1, the mouse Dlk2 gene and its locus at chromosome 17 are not fully characterized. RESULTS The goal of this work was the characterization of Dlk2 mRNA, as well as the analysis of the mechanisms that control its basal transcription. First, we analyzed the Dlk2 transcripts expressed by several mouse cells lines and tissues, and mapped the transcription start site by 5' Rapid Amplification of cDNA Ends. In silico analysis revealed that Dlk2 possesses a TATA-less promoter containing minimal promoter elements associated with a CpG island, and sequences for Inr and DPE elements. Besides, it possesses six GC-boxes, considered as consensus sites for the transcription factor Sp1. Indeed, we report that Sp1 directly binds to the Dlk2 promoter, activates its transcription, and regulates its level of expression. CONCLUSIONS Our results provide the first characterization of Dlk2 transcripts, map the location of the Dlk2 core promoter, and show the role of Sp1 as a key regulator of Dlk2 transcription, providing new insights into the molecular mechanisms that contribute to the expression of the Dlk2 gene.
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Affiliation(s)
- Samuel Rivero
- Facultad de Medicina/Centro Regional de Investigaciones Biomédicas, Universidad de Castilla-La Mancha, Calle Almansa 14, 02006 Albacete, Spain
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102
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Rodríguez P, Higueras MA, González-Rajal A, Alfranca A, Fierro-Fernández M, García-Fernández RA, Ruiz-Hidalgo MJ, Monsalve M, Rodríguez-Pascual F, Redondo JM, de la Pompa JL, Laborda J, Lamas S. The non-canonical NOTCH ligand DLK1 exhibits a novel vascular role as a strong inhibitor of angiogenesis. Cardiovasc Res 2011; 93:232-41. [PMID: 22068159 DOI: 10.1093/cvr/cvr296] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS The epidermal growth factor-like protein Delta-like 1 (DLK1) regulates multiple differentiation processes. It resembles NOTCH ligands structurally and is considered a non-canonical ligand. Given the crucial role of the NOTCH pathway in angiogenesis, we hypothesized that DLK1 could regulate angiogenesis by interfering with NOTCH. We therefore investigated the expression and function of DLK1 in the vascular endothelium and its role in the regulation of angiogenesis. METHODS AND RESULTS We report DLK1 expression in the endothelium of different species, including human, cow, pig, and mouse. Angiogenesis was studied by using in vitro and in vivo models of angiotube formation in endothelial cells, retinal phenotypes in Dlk1-null mice, and vessel development in zebrafish. DLK1 overexpression strongly inhibited angiotube formation, whereas lung endothelial cells from Dlk1-null mice were highly angiogenic. In vivo studies demonstrated DLK1-mediated inhibition of neovessel formation and revealed an altered pattern of angiogenesis in the retinas of Dlk1-null mice. The expression of human DLK1 in zebrafish embryos severely altered the formation of intersegmental vessels, while knockdown of the orthologous gene was associated with ectopic and increased tumour-induced angiogenesis. NOTCH-dependent signalling as determined by gene expression reporters was inhibited by the presence of DLK1 in vascular endothelial cells. In contrast, Dlk1-null mice showed increased levels of NOTCH downstream targets, such as Snail and Slug. CONCLUSION Our results unveil a novel inhibitory role for DLK1 in the regulation of angiogenesis, mediated by antagonism of the NOTCH pathway, and establish the basis for investigating its action in pathological settings.
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Affiliation(s)
- Patricia Rodríguez
- Laboratorio Mixto Consejo Superior de Investigaciones Científicas-Fundación Renal Iñigo Alvarez de Toledo, Centro de Biología Molecular Severo Ochoa, Nicolás Cabrera 1, 28029 Madrid, Spain
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103
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Lin J, Xiang D, Zhang JL, Allickson J, Xiang C. Plasticity of human menstrual blood stem cells derived from the endometrium. J Zhejiang Univ Sci B 2011; 12:372-80. [PMID: 21528491 DOI: 10.1631/jzus.b1100015] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Stem cells can be obtained from women's menstrual blood derived from the endometrium. The cells display stem cell markers such as Oct-4, SSEA-4, Nanog, and c-kit (CD117), and have the potent ability to differentiate into various cell types, including the heart, nerve, bone, cartilage, and fat. There has been no evidence of teratoma, ectopic formation, or any immune response after transplantation into an animal model. These cells quickly regenerate after menstruation and secrete many growth factors to display recurrent angiogenesis. The plasticity and safety of the acquired cells have been demonstrated in many studies. Menstrual blood-derived stem cells (MenSCs) provide an alternative source of adult stem cells for research and application in regenerative medicine. Here we summarize the multipotent properties and the plasticities of MenSCs and other endometrial stem cells from recent studies conducted both in vitro and in vivo.
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Affiliation(s)
- Jian Lin
- State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, the First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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104
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Postnatal loss of Dlk1 imprinting in stem cells and niche astrocytes regulates neurogenesis. Nature 2011; 475:381-5. [PMID: 21776083 PMCID: PMC3160481 DOI: 10.1038/nature10229] [Citation(s) in RCA: 213] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2010] [Accepted: 05/20/2011] [Indexed: 12/18/2022]
Abstract
The gene for the atypical Notch ligand Delta-like homologue 1 (Dlk1) encodes membrane-bound and secreted isoforms functioning in multiple developmental processes in vitro and in vivo. Dlk1, a member of a cluster of imprinted genes, is expressed from the paternally-inherited chromosome1,2. Here we show that mice deficient in Dlk1 exhibit defects in postnatal neurogenesis within the subventricular zone (SVZ), a developmental continuum resulting in depletion of mature neurons in the olfactory bulb. We show that DLK1 is a factor secreted by niche-astrocytes, while its membrane-bound isoform is present in neural stem cells (NSCs) being required for the inductive effect of secreted DLK1 on self-renewal. Surprisingly, we find a requirement for Dlk1 expressed from both maternal and paternally inherited chromosomes. Selective absence of Dlk1 imprinting in both NSCs and niche astrocytes is associated with postnatal acquisition of DNA methylation at the germ line-derived imprinting control region (IG-DMR). The results emphasize molecular relationships between NSCs and niche-astrocytes identifying a signalling system coded by a single gene functioning co-ordinately in both cell types. The modulation of genomic imprinting in a stem cell environment adds a new level of epigenetic regulation to the establishment and maintenance of the niche raising wider questions about the adaptability, function, and evolution of imprinting within specific developmental contexts.
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105
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Rusanescu G, Weissleder R, Aikawa E. Notch signaling in cardiovascular disease and calcification. Curr Cardiol Rev 2011; 4:148-56. [PMID: 19936191 PMCID: PMC2780816 DOI: 10.2174/157340308785160552] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2008] [Revised: 05/28/2008] [Accepted: 05/28/2008] [Indexed: 01/30/2023] Open
Abstract
Recent increase in human lifespan has shifted the spectrum of aging-related disorders to an unprecedented upsurge in cardiovascular diseases, especially calcific aortic valve stenosis, which has an 80% risk of progression to heart failure and death. A current therapeutic option for calcified valves is surgical replacement, which provides only temporary relief. Recent progress in cardiovascular research has suggested that arterial and valve calcification are the result of an active process of osteogenic differentiation, induced by a pro-atherogenic inflammatory response. At molecular level, the calcification process is regulated by a network of signaling pathways, including Notch, Wnt and TGFbeta/BMP pathways, which control the master regulator of osteogenesis Cbfa1/Runx2. Genetic and in vitro studies have implicated Notch signaling in the regulation of macrophage activation and cardiovascular calcification. Individuals with inactivating Notch1 mutations have a high rate of cardiovascular disorders, including valve stenosis and calcification. This article reviews recent progress in the mechanism of cardiovascular calcification and discusses potential molecular mechanisms involved, focusing on Notch receptors. We propose a calcification model where extreme increases in vascular wall cell density due to inflammation-induced cell proliferation can trigger an osteogenic differentiation program mediated by Notch receptors.
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Affiliation(s)
- Gabriel Rusanescu
- Center for Molecular Imaging Research, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
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106
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Migliaccio S, Greco EA, Fornari R, Donini LM, Lenzi A. Is obesity in women protective against osteoporosis? Diabetes Metab Syndr Obes 2011; 4:273-82. [PMID: 21792326 PMCID: PMC3139535 DOI: 10.2147/dmso.s11920] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/02/2011] [Indexed: 12/11/2022] Open
Abstract
The belief that obesity is protective against osteoporosis has recently come into question. The latest epidemiologic and clinical studies have shown that a high level of fat mass might be a risk factor for osteoporosis and fragility fractures. Further, increasing evidence seems to indicate that different components of the metabolic syndrome, ie, hypertension, increased triglycerides, reduced high-density lipoprotein cholesterol, are also potential risk factors for the development of low bone mineral density and osteoporosis. This review considers both the older and more recent data in the literature in order to evaluate further the relationship between fat tissue and bone tissue.
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Affiliation(s)
- Silvia Migliaccio
- Dipartimento di Medicina Sperimentale, Sezione di Fisiopatologia, Endocrinologia e Nutrizione, Università Sapienza di Roma
- Dipartimento di Scienze della Salute, Università Foro Italico di Roma, Italia
| | - Emanuela A Greco
- Dipartimento di Medicina Sperimentale, Sezione di Fisiopatologia, Endocrinologia e Nutrizione, Università Sapienza di Roma
| | - Rachele Fornari
- Dipartimento di Medicina Sperimentale, Sezione di Fisiopatologia, Endocrinologia e Nutrizione, Università Sapienza di Roma
| | - Lorenzo M Donini
- Dipartimento di Medicina Sperimentale, Sezione di Fisiopatologia, Endocrinologia e Nutrizione, Università Sapienza di Roma
| | - Andrea Lenzi
- Dipartimento di Medicina Sperimentale, Sezione di Fisiopatologia, Endocrinologia e Nutrizione, Università Sapienza di Roma
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107
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Abdallah BM, Ditzel N, Mahmood A, Isa A, Traustadottir GA, Schilling AF, Ruiz-Hidalgo MJ, Laborda J, Amling M, Kassem M. DLK1 is a novel regulator of bone mass that mediates estrogen deficiency-induced bone loss in mice. J Bone Miner Res 2011; 26:1457-71. [PMID: 21308776 DOI: 10.1002/jbmr.346] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Delta-like 1/fetal antigen 1 (DLK1/FA-1) is a transmembrane protein belonging to the Notch/Delta family that acts as a membrane-associated or a soluble protein to regulate regeneration of a number of adult tissues. Here we examined the role of DLK1/FA-1 in bone biology using osteoblast-specific Dlk1-overexpressing mice (Col1-Dlk1). Col1-Dlk1 mice displayed growth retardation and significantly reduced total body weight and bone mineral density (BMD). Micro-computed tomographis (µCT) scanning revealed a reduced trabecular and cortical bone volume fraction. Tissue-level histomorphometric analysis demonstrated decreased bone-formation rate and enhanced bone resorption in Col1-Dlk1 mice compared with wild-type mice. At a cellular level, Dlk1 markedly reduced the total number of bone marrow (BM)-derived colony-forming units fibroblasts (CFU-Fs), as well as their osteogenic capacity. In a number of in vitro culture systems, Dlk1 stimulated osteoclastogenesis indirectly through osteoblast-dependent increased production of proinflammatory bone-resorbing cytokines (eg, Il7, Tnfa, and Ccl3). We found that ovariectomy (ovx)-induced bone loss was associated with increased production of Dlk1 in the bone marrow by activated T cells. Interestingly, Dlk1(-/-) mice were significantly protected from ovx-induced bone loss compared with wild-type mice. Thus we identified Dlk1 as a novel regulator of bone mass that functions to inhibit bone formation and to stimulate bone resorption. Increasing DLK1 production by T cells under estrogen deficiency suggests its possible use as a therapeutic target for preventing postmenopausal bone loss.
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Affiliation(s)
- Basem M Abdallah
- Endocrine Research Laboratory, KMEB, Department of Endocrinology, and Medical Biotechnlogy Center, Odense University Hospital and University of Southern Denmark, Odense, Denmark.
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108
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Chen L, Qanie D, Jafari A, Taipaleenmaki H, Jensen CH, Säämänen AM, Sanz MLN, Laborda J, Abdallah BM, Kassem M. Delta-like 1/fetal antigen-1 (Dlk1/FA1) is a novel regulator of chondrogenic cell differentiation via inhibition of the Akt kinase-dependent pathway. J Biol Chem 2011; 286:32140-9. [PMID: 21724852 DOI: 10.1074/jbc.m111.230110] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Delta-like 1 (Dlk1, also known as fetal antigen-1, FA1) is a member of Notch/Delta family that inhibits adipocyte and osteoblast differentiation; however, its role in chondrogenesis is still not clear. Thus, we overexpressed Dlk1/FA1 in mouse embryonic ATDC5 cells and tested its effects on chondrogenic differentiation. Dlk1/FA1 inhibited insulin-induced chondrogenic differentiation as evidenced by reduction of cartilage nodule formation and gene expression of aggrecan, collagen Type II and X. Similar effects were obtained either by using Dlk1/FA1-conditioned medium or by addition of a purified, secreted, form of Dlk1 (FA1) directly to the induction medium. The inhibitory effects of Dlk1/FA1 were dose-dependent and occurred irrespective of the chondrogenic differentiation stage: proliferation, differentiation, maturation, or hypertrophic conversion. Overexpression or addition of the Dlk1/FA1 protein to the medium strongly inhibited the activation of Akt, but not the ERK1/2, or p38 MAPK pathways, and the inhibition of Akt by Dlk1/FA1 was mediated through PI3K activation. Interestingly, inhibition of fibronectin expression by siRNA rescued the Dlk1/FA1-mediated inhibition of Akt, suggesting interaction of Dlk1/FA1 and fibronectin in chondrogenic cells. Our results identify Dlk1/FA1 as a novel regulator of chondrogenesis and suggest Dlk1/FA1 acts as an inhibitor of the PI3K/Akt pathways that leads to its inhibitory effects on chondrogenesis.
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Affiliation(s)
- Li Chen
- Molecular Endocrinology Laboratory, Odense University Hospital, University of Southern Denmark, Odense DK-5000, Denmark
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109
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Sánchez-Solana B, Nueda ML, Ruvira MD, Ruiz-Hidalgo MJ, Monsalve EM, Rivero S, García-Ramírez JJ, Díaz-Guerra MJM, Baladrón V, Laborda J. The EGF-like proteins DLK1 and DLK2 function as inhibitory non-canonical ligands of NOTCH1 receptor that modulate each other's activities. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1153-64. [DOI: 10.1016/j.bbamcr.2011.03.004] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2010] [Revised: 02/19/2011] [Accepted: 03/07/2011] [Indexed: 12/23/2022]
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110
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Human Serum is as Efficient as Fetal Bovine Serum in Supporting Proliferation and Differentiation of Human Multipotent Stromal (Mesenchymal) Stem Cells In Vitro and In Vivo. Stem Cell Rev Rep 2011; 7:860-8. [DOI: 10.1007/s12015-011-9274-2] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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111
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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.
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Affiliation(s)
- K Arvidson
- Department of Clinical Dentistry, Center for Clinical Resarch, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway.
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112
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Kluth SM, Buchheiser A, Houben AP, Geyh S, Krenz T, Radke TF, Wiek C, Hanenberg H, Reinecke P, Wernet P, Kögler G. DLK-1 as a marker to distinguish unrestricted somatic stem cells and mesenchymal stromal cells in cord blood. Stem Cells Dev 2011; 19:1471-83. [PMID: 20331358 DOI: 10.1089/scd.2010.0070] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
In addition to hematopoietic stem cells, cord blood (CB) also contains different nonhematopoietic CD45-, CD34- adherent cell populations: cord blood mesenchymal stromal cells (CB MSC) that behave almost like MSC from bone marrow (BM MSC) and unrestricted somatic stem cells (USSC) that differentiate into cells of all 3 germ layers. Distinguishing between these populations is difficult due to overlapping features such as the immunophenotype or the osteogenic and chondrogenic differentiation pathway. Functional differences in the differentiation potential suggest different developmental stages or different cell populations. Here we demonstrate that the expression of genes and the differentiation toward the adipogenic lineage can discriminate between these 2 populations. USSC, including clonal-derived cells lacking adipogenic differentiation, strongly expressed δ-like 1/preadipocyte factor 1 (DLK-1/PREF1) correlating with high proliferative potential, while CB MSC were characterized by a strong differentiation toward adipocytes correlating with a weak or negative DLK-1/PREF1 expression. Constitutive overexpression of DLK-1/PREF1 in CB MSC resulted in a reduced adipogenic differentiation, whereas silencing of DLK-1 in USSC resulted in adipogenic differentiation.
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Affiliation(s)
- Simone Maria Kluth
- Institute for Transplantation Diagnostics and Cell Therapeutics, Heinrich Heine University Medical Center, Duesseldorf, Germany
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113
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Frost J, Monk D, Moschidou D, Guillot PV, Stanier P, Minger SL, Fisk NM, Moore HD, Moore GE. The effects of culture on genomic imprinting profiles in human embryonic and fetal mesenchymal stem cells. Epigenetics 2011; 6:52-62. [PMID: 20864803 DOI: 10.4161/epi.6.1.13361] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Human embryonic stem (hES) cells and fetal mesenchymal stem cells (fMSC) offer great potential for regenerative therapy strategies. It is therefore important to characterise the properties of these cells in vitro. One major way the environment impacts on cellular physiology is through changes to epigenetic mechanisms. Genes subject to epigenetic regulation via genomic imprinting have been characterised extensively. The integrity of imprinted gene expression therefore provides a measurable index for epigenetic stability. Allelic expression of 26 imprinted genes and DNA methylation at associated differentially methylated regions (DMRs) was measured in fMSC and hES cell lines. Both cell types exhibited monoallelic expression of 13 imprinted genes, biallelic expression of six imprinted genes, and there were seven genes that differed in allelic expression between cell lines. fMSCs exhibited the differential DNA methylation patterns associated with imprinted expression. This was unexpected given that gene expression of several imprinted genes was biallelic. However, in hES cells, differential methylation was perturbed. These atypical methylation patterns did not correlate with allelic expression. Our results suggest that regardless of stem cell origin, in vitro culture affects the integrity of imprinted gene expression in human cells. We identify biallelic and variably expressed genes that may inform on overall epigenetic stability. As differential methylation did not correlate with imprinted expression changes we propose that other epigenetic effectors are adversely influenced by the in vitro environment. Since DMR integrity was maintained in fMSC but not hES cells, we postulate that specific hES cell derivation and culturing practices result in changes in methylation at DMRs.
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Affiliation(s)
- Jennifer Frost
- Institute of Reproductive and Developmental Biology, Imperial Colleg, London, UK.
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114
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Syed FA, Hoey KA. Integrative physiology of the aging bone: insights from animal and cellular models. Ann N Y Acad Sci 2010; 1211:95-106. [PMID: 21062298 DOI: 10.1111/j.1749-6632.2010.05813.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Age-related bone loss is a common worldwide phenomenon in the aging population, placing them at an increased risk of fractures. Fortunately, basic and translational studies have been pivotal in providing us with a mechanistic understanding of the cellular and molecular pathophysiology of this condition. This review focuses on the current concepts and paradigms of age-related bone loss and how various animal and cellular models have broadened our understanding in this fascinating but complex area. Changes in hormonal, neuronal, and biochemical cues with age and their effect on bone have been discussed. This review also outlines recent studies on the relationship between bone and fat in the marrow, as well as the fate of the marrow mesenchymal stromal cell population, which can give rise to either bone-forming osteoblasts or fat-forming adipocytic cells as a function of age.
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Affiliation(s)
- Farhan A Syed
- Abbott Bioresearch Center, Worcester, Massachusetts, USA.
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115
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Oczkowicz M, Piestrzyska-Kajtoch A, Piórkowska K, Rejduch B, Rózycki M. Expression of DLK1 and MEG3 genes in porcine tissues during postnatal development. Genet Mol Biol 2010; 33:790-4. [PMID: 21637593 PMCID: PMC3036157 DOI: 10.1590/s1415-47572010000400030] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Accepted: 06/11/2010] [Indexed: 01/03/2023] Open
Abstract
The Drosophila-like homolog 1 (DLK1), a transmembrane signal protein similar to other members of the Notch/Delta/Serrate family, regulates the differentiation process in many types of mammalian cells. Callipyge sheep and DLK1 knockout mice are excellent examples of a fundamental role of the gene encoding DLK1 in muscle growth and fat deposition. DLK1 is located within co-regulated imprinted clusters (the DLK1/DIO3 domain), along with other imprinted genes. Some of these, e.g. the RNA coding MEG3 gene, presumedly interfere with DLK1 transcription. The aim of our study was to analyze DLK1 and MEG3 gene expression in porcine tissues (muscle, liver, kidney, heart, brain stem) during postnatal development. The highest expression of both DLK1 and MEG3 variant 1 (MEG3 var.1) was observed in the brain-stem and muscles, whereas that of MEG3 variant 2 (MEG3var.2) was the most abundant in muscles and the heart. During development (between 60 and 210 days of age) expression of analyzed genes was down-regulated in all the tissues. An exception was the brain- stem, where there was no significant change in MEG3 (both variants) mRNA level, and relatively little decline (2-fold) in that of DLK1 transcription. This may indicate a distinct function of the DLK1 gene in the brain-stem, when compared with other tissues.
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Affiliation(s)
- Maria Oczkowicz
- Department of Genetics and Animal Breeding, National Research Institute of Animal Production, Balice Poland
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116
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Yi C, Liu D, Fong CC, Zhang J, Yang M. Gold nanoparticles promote osteogenic differentiation of mesenchymal stem cells through p38 MAPK pathway. ACS NANO 2010; 4:6439-48. [PMID: 21028783 DOI: 10.1021/nn101373r] [Citation(s) in RCA: 293] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Understanding the interaction mechanisms between nanomaterials and biological cells is important for the control and manipulation of these interactions for biomedical applications. In this study, we investigated the cellular effects of gold nanoparticles (AuNPs) on the differentiation of mesenchymal stem cells (MSCs) and the associated molecular mechanisms. The results showed that AuNPs promoted the differentiation of MSCs toward osteoblast cells over adipocyte cells by inducing an enhanced osteogenic transcriptional profile and an attenuated adipogenic transcriptional profile. AuNPs exerted the effects by interacting with the cell membrane and binding with proteins in the cytoplasm, causing mechanical stress on the MSCs to activate p38 mitogen-activated protein kinase pathway (MAPK) signaling pathway, which regulates the expression of relevant genes to induce osteogenic differentiation and inhibit adipogenic differentiation.
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Affiliation(s)
- Changqing Yi
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China
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117
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Kupisiewicz K, Boissy P, Abdallah BM, Hansen FD, Erben RG, Savouret JF, Søe K, Andersen TL, Plesner T, Delaisse JM. Potential of resveratrol analogues as antagonists of osteoclasts and promoters of osteoblasts. Calcif Tissue Int 2010; 87:437-49. [PMID: 20842496 PMCID: PMC2964465 DOI: 10.1007/s00223-010-9399-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2009] [Accepted: 06/11/2010] [Indexed: 12/31/2022]
Abstract
The plant phytoalexin resveratrol was previously demonstrated to inhibit the differentiation and bone resorbing activity of osteoclasts, to promote the formation of osteoblasts from mesenchymal precursors in cultures, and inhibit myeloma cell proliferation, when used at high concentrations. In the current study, we screened five structurally modified resveratrol analogues for their ability to modify the differentiation of osteoclasts and osteoblasts and proliferation of myeloma cells. Compared to resveratrol, analogues showed an up to 5,000-fold increased potency to inhibit osteoclast differentiation. To a lesser extent, resveratrol analogues also promoted osteoblast maturation. However, they did not antagonize the proliferation of myeloma cells. The potency of the best-performing candidate in vitro was tested in vivo in an ovariectomy-induced model of osteoporosis, but an effect on bone loss could not be detected. Based on their powerful antiresorptive activity in vitro, resveratrol analogues might be attractive modulators of bone remodeling. However, further studies are required to establish their efficacy in vivo.
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Affiliation(s)
- Katarzyna Kupisiewicz
- Division of Hematology, Department of Clinical Cell Biology, Vejle Hospital, IRS/CSFU, University of Southern Denmark, Vejle, Denmark.
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Vorotnikova E, McIntosh D, Dewilde A, Zhang J, Reing JE, Zhang L, Cordero K, Bedelbaeva K, Gourevitch D, Heber-Katz E, Badylak SF, Braunhut SJ. Extracellular matrix-derived products modulate endothelial and progenitor cell migration and proliferation in vitro and stimulate regenerative healing in vivo. Matrix Biol 2010; 29:690-700. [PMID: 20797438 DOI: 10.1016/j.matbio.2010.08.007] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2009] [Revised: 08/05/2010] [Accepted: 08/17/2010] [Indexed: 12/13/2022]
Abstract
Most adult mammals heal without restorative replacement of lost tissue and instead form scar tissue at an injury site. One exception is the adult MRL/MpJ mouse that can regenerate ear and cardiac tissue after wounding with little evidence of scar tissue formation. Following production of a MRL mouse ear hole, 2mm in diameter, a structure rapidly forms at the injury site that resembles the amphibian blastema at a limb amputation site during limb regeneration. We have isolated MRL blastemal cells (MRL-B) from this structure and adapted them to culture. We demonstrate by RT-PCR that even after continuous culturing of these cells they maintain expression of several progenitor cell markers, including DLK (Pref-1), and Msx-1. We have isolated the underlying extracellular matrix (ECM) produced by these MRL-B cells using a new non-proteolytic method and studied the biological activities of this cell-free ECM. Multiplex microELISA analysis of MRL-B cell-free ECM vs. cells revealed selective enrichment of growth factors such as bFGF, HGF and KGF in the matrix compartment. The cell-free ECM, degraded by mild enzyme treatment, was active in promoting migration and proliferation of progenitor cells in vitro and accelerating wound closure in a mouse full thickness cutaneous wound assay in vivo. In vivo, a single application of MRL-B cell matrix-derived products to full thickness cutaneous wounds in non-regenerative mice, B6, induced re-growth of pigmented hair, dermis and epidermis at the wound site whereas scar tissue replaced these tissues at wound sites in mice treated with vehicle alone. These studies suggest that matrix-derived products can stimulate regenerative healing and avert scar tissue formation in adult mammals.
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Affiliation(s)
- Ekaterina Vorotnikova
- Department of Biological Sciences, University of Massachusetts, Lowell, MA 01854, USA
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119
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Zhou Y, Cheunsuchon P, Nakayama Y, Lawlor MW, Zhong Y, Rice KA, Zhang L, Zhang X, Gordon FE, Lidov HGW, Bronson RT, Klibanski A. Activation of paternally expressed genes and perinatal death caused by deletion of the Gtl2 gene. Development 2010; 137:2643-52. [PMID: 20610486 DOI: 10.1242/dev.045724] [Citation(s) in RCA: 115] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The Dlk1-Gtl2 imprinting locus is located on mouse distal chromosome 12 and consists of multiple maternally expressed non-coding RNAs and several paternally expressed protein-coding genes. The imprinting of this locus plays a crucial role in embryonic development and postnatal growth. At least one cis-element, the intergenic differentially methylated region (IG-DMR) is required for expression of maternally expressed genes and repression of silenced paternally expressed genes. The mechanism by which the IG-DMR functions is largely unknown. However, it has been suggested that the unmethylated IG-DMR acts as a positive regulator activating expression of non-coding RNAs. Gtl2 is the first non-coding RNA gene downstream of the IG-DMR. Although its in vivo function in the mouse is largely unknown, its human ortholog MEG3 has been linked to tumor suppression in human tumor-derived cell lines. We generated a knockout mouse model, in which the first five exons and adjacent promoter region of the Gtl2 gene were deleted. Maternal deletion of Gtl2 resulted in perinatal death and skeletal muscle defects, indicating that Gtl2 plays an important role in embryonic development. The maternal deletion also completely abolished expression of downstream maternally expressed genes, activated expression of silenced paternally expressed genes and resulted in methylation of the IG-DMR. By contrast, the paternal inherited deletion did not have this effect. These data strongly indicate that activation of Gtl2 and its downstream maternal genes play an essential role in regulating Dlk1-Gtl2 imprinting, possibly by maintaining active status of the IG-DMR.
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Affiliation(s)
- Yunli Zhou
- Massachusetts General Hospital, Boston, MA 02114, USA.
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120
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Andersen DC, Jensen CH, Schneider M, Nossent AY, Eskildsen T, Hansen JL, Teisner B, Sheikh SP. MicroRNA-15a fine-tunes the level of Delta-like 1 homolog (DLK1) in proliferating 3T3-L1 preadipocytes. Exp Cell Res 2010; 316:1681-91. [PMID: 20385127 DOI: 10.1016/j.yexcr.2010.04.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2009] [Revised: 02/28/2010] [Accepted: 04/04/2010] [Indexed: 11/16/2022]
Abstract
Delta like 1 homolog (Dlk1) exists in both transmembrane and soluble molecular forms, and is implicated in cellular growth and plays multiple roles in development, tissue regeneration, and cancer. Thus, DLK1 levels are critical for cell function, and abnormal DLK1 expression can be lethal; however, little is known about the underlying mechanisms. We here report that miR-15a modulates DLK1 levels in preadipocytes thus providing a mechanism for DLK1 regulation that further links it to cell cycle arrest and cancer since miR-15a is deregulated in these processes. In preadipocytes, miR-15a increases with cell density, and peaks at the same stage where membrane DLK1(M) and soluble DLK1(S) are found at maximum levels. Remarkably, miR-15a represses the amount of all Dlk1 variants at the mRNA level but also the level of DLK1(M) protein while it increases the amount of DLK1(S) supporting a direct repression of DLK1 and a parallel effect on the protease that cleaves off the DLK1 from the membrane. In agreement with previous studies, we found that miR-15a represses cell numbers, but additionally, we report that miR-15a also increases cell size. Conversely, anti-miR-15a treatment decreases cell size while increasing cell numbers, scenarios that were completely rescued by addition of purified DLK1(S). Our data thus imply that miR-15a regulates cell size and proliferation by fine-tuning Dlk1 among others, and further emphasize miR-15a and DLK1 levels to play important roles in growth signaling networks.
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Affiliation(s)
- Ditte C Andersen
- Laboratory of Molecular and Cellular Cardiology, Department of Biochemistry, Pharmacology and Genetics, Odense University Hospital, University of Southern Denmark, Winsløwparken 21.3, DK-5000 Odense C, Denmark
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121
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Gueller S, Komor M, Nowak D, Baldus CD, de Vos S, Hoelzer D, Ottmann OG, Hofmann WK. Identification of defects in the transcriptional program during lineage-specific in vitro differentiation of CD34(+) cells selected from patients with both low- and high-risk myelodysplastic syndrome. Exp Hematol 2010; 38:718-32, 732.e1-6. [PMID: 20621626 DOI: 10.1016/j.exphem.2010.04.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2009] [Revised: 04/01/2010] [Accepted: 04/27/2010] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Development of myelodysplastic syndrome (MDS) is suggested to follow a multistep pathogenesis and is characterized by accumulation of molecular defects of the hematopoietic stem/progenitor cells, resulting in aberrant differentiation and proliferation. MATERIALS AND METHODS To detect alterations within the transcriptional program in MDS-derived CD34(+) cells during lineage-specific differentiation, we performed serial gene expression analysis of in vitro differentiated erythro-, granulo-, and megakaryopoietic cells using oligonucleotide microarrays (HG-U133A, Affymetrix, Santa Clara, CA, USA). For selected genes, expression data were confirmed using real-time polymerase chain reaction. RESULTS We identified genes with altered expression during lineage-specific differentiation in either low- or high-risk MDS cells compared to the expression patterns of continuously up- or downregulated genes from the normal transcriptional program of hematopoiesis. In cluster analyses, we could show that MDS samples have a distinct expression pattern of a set of selected genes compared to normal cells, which allows prediction of the affiliation of a sample to one group. Furthermore, this study gives an overview of genes that are differentially expressed in MDS cells compared to normal hematopoiesis. CONCLUSION Our data provide the first comprehensive transcriptional analysis of differentiating human CD34(+) cells derived from MDS patients compared to normal individuals. It gives new insights into the alteration of differentiation and proliferation of MDS stem cells.
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Affiliation(s)
- Saskia Gueller
- Department of Hematology and Oncology, University Hospital, Frankfurt/Main, Germany
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122
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Liu D, Yi C, Zhang D, Zhang J, Yang M. Inhibition of proliferation and differentiation of mesenchymal stem cells by carboxylated carbon nanotubes. ACS NANO 2010; 4:2185-95. [PMID: 20218664 DOI: 10.1021/nn901479w] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Multipotent mesenchymal stem cells (MSCs) have attracted substantial attention in stem cell therapy and tissue engineering due to their ability to be cultured for successive passages and multilineage differentiation. Carbon nanotubes (CNTs) have been proposed to be used as potential biomedical structures for bone formation. Therefore, it is important to study the mechanisms of interaction between MSCs and CNTs. We demonstrated that carboxylated single-walled carbon nanotubes (SWCNTs) and carboxylated multiwalled carbon nanotubes (MWCNTs) inhibited the proliferation, osteogenic differentiation, adipogenic differentiation, and mineralization of MSCs. Oxidative stress assay indicated that reactive oxygen species (ROS) may not be responsible for the observed cytotoxicity of carboxylated CNTs. Quantitative real-time polymerase chain reaction (Q-PCR) experiments confirmed that the expression of osteoblast specific genes and adipocyte differentiation specific genes was greatly attenuated during the differentiation of MSCs in the presence of carboxylated CNTs. TEM images revealed that CNTs might interact with proteins located on the cell membrane or in the cytoplasm, which have a further impact on subsequent cellular signaling pathways. Q-PCR results and Western blot analysis together verified that the inhibition of proliferation and osteogenic differentiation of MSCs may be modulated through a Smad-dependent bone morphogenetic protein (BMP) signaling pathway.
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Affiliation(s)
- Dandan Liu
- Key Laboratory of Biochip Technology, Biotech and Health Centre, Shenzhen Research Institute of City University of Hong Kong, Shenzhen, China
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123
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Sims-Lucas S, Young RJ, Martinez G, Taylor D, Grimmond SM, Teasdale R, Little MH, Bertram JF, Caruana G. Redirection of renal mesenchyme to stromal and chondrocytic fates in the presence of TGF-β2. Differentiation 2010; 79:272-84. [DOI: 10.1016/j.diff.2010.01.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2009] [Revised: 01/14/2010] [Accepted: 01/31/2010] [Indexed: 02/04/2023]
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124
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Zhang X, Gejman R, Mahta A, Zhong Y, Rice KA, Zhou Y, Cheunsuchon P, Louis DN, Klibanski A. Maternally expressed gene 3, an imprinted noncoding RNA gene, is associated with meningioma pathogenesis and progression. Cancer Res 2010; 70:2350-8. [PMID: 20179190 DOI: 10.1158/0008-5472.can-09-3885] [Citation(s) in RCA: 275] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Meningiomas are common tumors, representing 15% to 25% of all central nervous system tumors. NF2 gene inactivation on chromosome 22 has been shown as an early event in tumorigenesis; however, few factors underlying tumor growth and progression have been identified. The chromosomal abnormalities of 14q32 are often associated with meningioma pathogenesis and progression; therefore, it has been proposed that an as yet unidentified tumor suppressor is present at this locus. Maternally expressed gene 3 (MEG3) is an imprinted gene located at 14q32 which encodes a noncoding RNA with an antiproliferative function. We found that MEG3 mRNA is highly expressed in normal arachnoidal cells. However, MEG3 is not expressed in the majority of human meningiomas or the human meningioma cell lines IOMM-Lee and CH157-MN. There is a strong association between loss of MEG3 expression and tumor grade. Allelic loss at the MEG3 locus is also observed in meningiomas, with increasing prevalence in higher grade tumors. In addition, there is an increase in CpG methylation within the promoter and the imprinting control region of MEG3 gene in meningiomas. Functionally, MEG3 suppresses DNA synthesis in both IOMM-Lee and CH157-MN cells by approximately 60% in bromodeoxyuridine incorporation assays. Colony-forming efficiency assays show that MEG3 inhibits colony formation in CH157-MN cells by approximately 80%. Furthermore, MEG3 stimulates p53-mediated transactivation in these cell lines. Therefore, these data are consistent with the hypothesis that MEG3, which encodes a noncoding RNA, may be a tumor suppressor gene at chromosome 14q32 involved in meningioma progression via a novel mechanism.
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Affiliation(s)
- Xun Zhang
- Neuroendocrine Unit and Department of Pathology, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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125
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Abstract
The craniofacial and oral manifestations of the different epidermolysis bullosa (EB) types vary markedly in character and severity depending largely on the EB type. The tissues affected and the phenotypes displayed are closely related to the specific abnormal or absent proteins resulting from the causative genetic mutations for these disorders. In this article, the major oral manifestations are reviewed for different EB subtypes and are related to the causative genetic mutations and gene expression.
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126
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Wang Y, Hudak C, Sul HS. Role of preadipocyte factor 1 in adipocyte differentiation. ACTA ACUST UNITED AC 2010; 5:109-115. [PMID: 20414356 DOI: 10.2217/clp.09.80] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Preadipocyte factor 1 (Pref-1) is an EGF-repeat-containing transmembrane protein that inhibits adipogenesis. The extracellular domain of Pref-1 is cleaved by TNF-α converting enzyme to generate the biologically active soluble form of Pref-1. The role of Pref-1 in adipogenesis has been firmly established by in vitro and in vivo studies. Pref-1 activates ERK/MAPK and upregulates Sox9 expression to inhibit adipocyte differentiation. Sox9 directly binds to the promoter regions of CCAAT/enhancer-binding protein-β and CCAAT/enhancer-binding protein-δ in order to suppress their promoter activities in preventing adipocyte differentiation. Here, we describe the function of Pref-1 in adipocyte differentiation and the recent findings on the mechanisms by which Pref-1 inhibits adipocyte differentiation.
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Affiliation(s)
- Yuhui Wang
- Department of Nutritional Science & Toxicology, University of California, Berkeley, CA 94720, USA, Tel.: +1 510 642 3978, ,
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127
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Miyaoka Y, Tanaka M, Imamura T, Takada S, Miyajima A. A novel regulatory mechanism for Fgf18 signaling involving cysteine-rich FGF receptor (Cfr) and delta-like protein (Dlk). Development 2010; 137:159-67. [PMID: 20023171 DOI: 10.1242/dev.041574] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fibroblast growth factors (FGFs) transduce signals through FGF receptors (FGFRs) and have pleiotropic functions. Besides signal-transducing FGFRs, cysteine-rich FGF receptor (Cfr; Glg1) is also known to bind some FGFs, although its physiological functions remain unknown. In this study, we generated Cfr-deficient mice and found that some of them die perinatally, and show growth retardation, tail malformation and cleft palate. These phenotypes are strikingly similar to those of Fgf18-deficient mice, and we revealed interaction between Cfr and Fgf18 both genetically and physically, suggesting functional cooperation. Consistently, introduction of Cfr facilitated Fgf18-dependent proliferation of Ba/F3 cells expressing Fgfr3c. In addition, we uncovered binding between Cfr and delta-like protein (Dlk), and noticed that Cfr-deficient mice are also similar to Dlk-transgenic mice, indicating that Cfr and Dlk function in opposite ways. Interestingly, we also found that Dlk interrupts the binding between Cfr and Fgf18. Thus, the Fgf18 signaling pathway seems to be finely tuned by Cfr and Dlk for skeletal development. This study reveals a novel regulatory mechanism for Fgf18 signaling involving Cfr and Dlk.
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Affiliation(s)
- Yuichiro Miyaoka
- Laboratory of Cell Growth and Differentiation, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
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128
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Fazeli PK, Bredella MA, Misra M, Meenaghan E, Rosen CJ, Clemmons DR, Breggia A, Miller KK, Klibanski A. Preadipocyte factor-1 is associated with marrow adiposity and bone mineral density in women with anorexia nervosa. J Clin Endocrinol Metab 2010; 95:407-13. [PMID: 19850693 PMCID: PMC2805488 DOI: 10.1210/jc.2009-1152] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Despite having low visceral and sc fat depots, women with anorexia nervosa (AN) have elevated marrow fat mass, which is inversely associated with bone mineral density (BMD). Adipocytes and osteoblasts differentiate from a common progenitor cell, the human mesenchymal stem cell. Therefore, understanding factors that regulate this differentiation process may provide insight into bone loss in AN. OBJECTIVE The objective of the study was to investigate the relationship between preadipocyte factor-1 (Pref-1), a member of the epidermal growth factor-like family of proteins and regulator of adipocyte and osteoblast differentiation, and fat depots and BMD in AN. DESIGN This was a cross-sectional study. SETTING The study was conducted at a clinical research center. PATIENTS Patients included 20 women with AN (26.8 +/- 1.5 yr) and 10 normal-weight controls (29.2 +/- 1.7 yr). INTERVENTIONS There were no interventions. MAIN OUTCOMES MEASURE Pref-1, leptin, IGF-I, IGF binding protein (IGF-BP)-2 and estradiol levels were measured. BMD of the spine and hip was measured by dual-energy x-ray absorptiometry. Marrow fat content of the L4 vertebra and femur was measured by (1)H-magnetic resonance spectroscopy. RESULTS Pref-1 levels were significantly higher in AN compared with controls (P = 0.01). There was a positive correlation between Pref-1 and marrow fat of the proximal femoral metaphysis (R = 0.50, P = 0.01) and an inverse association between leptin and L4 marrow fat (R = -0.45, P < 0.05). There was an inverse association between Pref-1 and BMD of both the anteroposterior spine and lateral spine (R = -0.54, P = 0.003; R = -0.44, P = 0.02, respectively). CONCLUSIONS Pref-1 is elevated in AN. Pref-1, IGF-I, IGF-BP2 and leptin are associated with marrow adiposity and BMD.
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Affiliation(s)
- Pouneh K Fazeli
- Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, Boston, Massachusetts 02114, USA
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129
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Epimorphic regeneration approach to tissue replacement in adult mammals. Proc Natl Acad Sci U S A 2009; 107:3351-5. [PMID: 19966310 DOI: 10.1073/pnas.0905851106] [Citation(s) in RCA: 127] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Urodeles and fetal mammals are capable of impressive epimorphic regeneration in a variety of tissues, whereas the typical default response to injury in adult mammals consists of inflammation and scar tissue formation. One component of epimorphic regeneration is the recruitment of resident progenitor and stem cells to a site of injury. Bioactive molecules resulting from degradation of extracellular matrix (ECM) have been shown to recruit a variety of progenitor and stem cells in vitro in adult mammals. The ability to recruit multipotential cells to the site of injury by in vivo administration of chemotactic ECM degradation products in a mammalian model of digit amputation was investigated in the present study. Adult, 6- to 8-week-old C57/BL6 mice were subjected to midsecond phalanx amputation of the third digit of the right hind foot and either treated with chemotactic ECM degradation products or left untreated. At 14 days after amputation, mice treated with ECM degradation products showed an accumulation of heterogeneous cells that expressed markers of multipotency, including Sox2, Sca1, and Rex1 (Zfp42). Cells isolated from the site of amputation were capable of differentiation along neuroectodermal and mesodermal lineages, whereas cells isolated from control mice were capable of differentiation along only mesodermal lineages. The present findings demonstrate the recruitment of endogenous stem cells to a site of injury, and/or their generation/proliferation therein, in response to ECM degradation products.
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130
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Harkness L, Taipaleenmaki H, Mahmood A, Frandsen U, Saamanen AM, Kassem M, Abdallah BM. Isolation and Differentiation of Chondrocytic Cells Derived from Human Embryonic Stem Cells Using dlk1/FA1 as a Novel Surface Marker. Stem Cell Rev Rep 2009; 5:353-68. [DOI: 10.1007/s12015-009-9099-4] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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131
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Andersen DC, Jensen L, Schrøder HD, Jensen CH. "The preadipocyte factor" DLK1 marks adult mouse adipose tissue residing vascular cells that lack in vitro adipogenic differentiation potential. FEBS Lett 2009; 583:2947-53. [PMID: 19665021 DOI: 10.1016/j.febslet.2009.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Accepted: 08/03/2009] [Indexed: 01/22/2023]
Abstract
Delta-like 1 (Dlk1) is expressed in 3T3-L1 preadipocytes and has frequently been referred to as "the" preadipocyte marker, yet the phenotype of DLK1(+) cells in adipose tissue remains undetermined. Herein, we demonstrate that DLK1(+) cells encompass around 1-2% of the adult mouse adipose stromal vascular fraction (SVF). Unexpectedly, the DLK1(+)SVF population was enriched for cells expressing genes generally ascribed to the vascular lineage and did not possess any adipogenic differentiation potential in vitro. Instead, DLK1(+) cells comprised an immediate ability for cobblestone formation, generation of tube-like structures on matrigel, and uptake of Acetylated Low Density-Lipoprotein, all characteristics of endothelial cells. We therefore suggest that DLK1(+)SVF cells are of a vascular origin and not them-selves committed preadipocytes as assumed hitherto.
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132
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Shin J, Velleman S, Latshaw J, Wick M, Suh Y, Lee K. The ontogeny of delta-like protein 1 messenger ribonucleic acid expression during muscle development and regeneration: Comparison of broiler and Leghorn chickens. Poult Sci 2009; 88:1427-37. [DOI: 10.3382/ps.2008-00529] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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133
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Andersen DC, Petersson SJ, Jørgensen LH, Bollen P, Jensen PB, Teisner B, Schroeder HD, Jensen CH. Characterization of DLK1+ cells emerging during skeletal muscle remodeling in response to myositis, myopathies, and acute injury. Stem Cells 2009; 27:898-908. [PMID: 19353518 DOI: 10.1634/stemcells.2008-0826] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Delta like 1 (DLK1) has been proposed to act as a regulator of cell fate determination and is linked to the development of various tissues including skeletal muscle. Herein we further investigated DLK1 expression during skeletal muscle remodeling. Although practically absent in normal adult muscle, DLK1 was upregulated in all human myopathies analyzed, including Duchenne- and Becker muscular dystrophies. Substantial numbers of DLK1(+) satellite cells were observed in normal neonatal and Duchenne muscle, and furthermore, myogenic DLK1(+) cells were identified during muscle regeneration in animal models in which the peak expression of Dlk1 mRNA and protein coincided with that of myoblast differentiation and fusion. In addition to perivascular DLK1(+) cells, interstitial DLK1(+) cells were numerous in regenerating muscle, and in agreement with colocalization studies of DLK1 and CD90/DDR2, qPCR of fluorescence-activated cell sorting DLK1(+) and DLK1(-) cells revealed that the majority of DLK1(+) cells isolated at day 7 of regeneration had a fibroblast-like phenotype. The existence of different DLK1(+) populations was confirmed in cultures of primary derived myogenic cells, in which large flat nonmyogenic DLK1(+) cells and small spindle-shaped cells coexpressing DLK1 and muscle-specific markers were observed. Myogenic differentiation was achieved when sorted DLK1(+) cells were cocultured together with primary myoblasts revealing a myogenic potential that was 10% of the DLK1(-) population. Transplantation of DLK1(+) cells into lacerated muscle did, however, not give rise to DLK1(+) cell-derived myofibers. We suggest that the DLK1(+) subpopulations identified herein each may contribute at different levels/time points to the processes involved in muscle development and remodeling.
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Affiliation(s)
- Ditte C Andersen
- Department of Clinical Pathology, Odense University Hospital, Odense C, Denmark
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134
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Abstract
Preadipocyte factor-1 [Pref-1; also called Dlk1 (Delta-like protein 1)] is made as an epidermal growth factor-repeat containing transmembrane protein that produces a biologically active soluble form by TNF-alpha-converting enzyme (TACE)-mediated cleavage. Soluble Pref-1 activates the MAPK kinase/ERK pathway. In adipose tissue, Pref-1 is specifically expressed in preadipocytes but not in adipocytes and thus is used as a preadipocyte marker. Inhibition of adipogenesis by Pref-1 has been well established in vitro as well as in vivo by ablation and overexpression of Pref-1. SRY (sex determining region Y)-box 9 (Sox9), a transcription factor expressed in preadipocytes to suppress CCAAT enhancer binding protein beta and (C/EBP) delta expression, is required to be down-regulated before adipocyte differentiation can proceed. By activating MAPK kinase/ERK, Pref-1 prevents down-regulation of Sox9, resulting in inhibition of adipogenesis. Furthermore, by inducing Sox9, Pref-1 promotes chondrogenic induction of mesenchymal cells but prevents chondrocyte maturation as well as osteoblast differentiation. Thus, Pref-1 directs multipotent mesenchymal cells toward the chondrogenic lineage but inhibits differentiation into adipocytes as well as osteoblasts and chondrocytes. Pref-1, encoded by an imprinted gene, has also been detected in progenitor cells in various tissues during regeneration and therefore may have a more general role in maintaining cells in an undifferentiated state.
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Affiliation(s)
- Hei Sook Sul
- Department of Nutritional Science and Toxicology, University of California, Berkeley, California 94720, USA.
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Jacobs FMJ, van der Linden AJA, Wang Y, von Oerthel L, Sul HS, Burbach JPH, Smidt MP. Identification of Dlk1, Ptpru and Klhl1 as novel Nurr1 target genes in meso-diencephalic dopamine neurons. Development 2009; 136:2363-73. [PMID: 19515692 DOI: 10.1242/dev.037556] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The orphan nuclear receptor Nurr1 is essential for the development of meso-diencephalic dopamine (mdDA) neurons and is required, together with the homeobox transcription factor Pitx3, for the expression of genes involved in dopamine metabolism. In order to elucidate the molecular mechanisms that underlie the neuronal deficits in Nurr1(-/-) mice, we performed combined gene expression microarrays and ChIP-on-chip analysis and thereby identified Dlk1, Ptpru and Klhl1 as novel Nurr1 target genes in vivo. In line with the previously described cooperativity between Nurr1 and Pitx3, we show that the expression of Ptpru and Klhl1 in mdDA neurons is also dependent on Pitx3. Furthermore, we demonstrate that Nurr1 interacts with the Ptpru promoter directly and requires Pitx3 for full expression of Ptpru in mdDA neurons. By contrast, the expression of Dlk1 is maintained in Pitx3(-/-) embryos and is even expanded into the rostral part of the mdDA area, suggesting a unique position of Dlk1 in the Nurr1 and Pitx3 transcriptional cascades. Expression analysis in Dlk1(-/-) embryos reveals that Dlk1 is required to prevent premature expression of Dat in mdDA neuronal precursors as part of the multifaceted process of mdDA neuronal differentiation driven by Nurr1 and Pitx3. Taken together, the involvement of Nurr1 and Pitx3 in the expression of novel target genes involved in important neuronal processes such as neuronal patterning, axon outgrowth and terminal differentiation, opens up new avenues to study the properties of mdDA neurons during development and in neuronal pathology as observed in Parkinson's disease.
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Affiliation(s)
- Frank M J Jacobs
- Rudolf Magnus Institute of Neuroscience, Department of Neuroscience and Pharmacology, University Medical Center Utrecht, Universiteitsweg 100, 3584 CG, Utrecht, The Netherlands
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136
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Expression regulation and function of Pref-1 during adipogenesis of human mesenchymal stem cells (MSCs). Biochim Biophys Acta Mol Cell Biol Lipids 2009; 1791:816-26. [PMID: 19427405 DOI: 10.1016/j.bbalip.2009.04.010] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2009] [Revised: 04/27/2009] [Accepted: 04/28/2009] [Indexed: 12/16/2022]
Abstract
Preadipocyte Factor 1 (Pref-1), also known as Delta-like Protein 1 (DLK-1) is an epidermal growth factor-like domain-containing trans-membrane protein that is involved in adipogenesis and cell fate decision. Its function in adipogenesis is reported inconsistently based on different cellular model systems. Here, by using human mesenchymal stem cells (MSCs), we show that Pref-1 is modulated by both dexamethasone and 3-isobutyl-1methylxanthine (IBMX), two components of the adipogenic induction mixture during the adipogenesis in vitro. IBMX induces the expression of Pref-1 in a time- and dose-dependent manner through cyclic AMP and cyclic GMP independent pathway and attenuates adipocyte differentiation by down-regulating PPARgamma (peroxisome proliferator activated receptor gamma) expression. Dexamethasone, on the other hand, is capable of subduing the inhibitory effect of IBMX-induced Pref-1 and initiating the adipogenesis by up-regulating PPARgamma expression. Moreover, the treatment of IBMX or dexamethasone alone fails to develop MSCs into mature adipocytes, however, treating cells with both IBMX and dexamethasone leads to a complete adipocyte differentiation as evaluated by lipid-droplet formation. Taken together, our study demonstrates that IBMX accelerates accumulation of lipid in MSCs only under the circumstance that the negative effect of Pref-1 induced by IBMX on the adipogenesis is overcome by dexamethasone.
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137
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Reing JE, Zhang L, Myers-Irvin J, Cordero KE, Freytes DO, Heber-Katz E, Bedelbaeva K, McIntosh D, Dewilde A, Braunhut SJ, Badylak SF. Degradation products of extracellular matrix affect cell migration and proliferation. Tissue Eng Part A 2009; 15:605-14. [PMID: 18652541 DOI: 10.1089/ten.tea.2007.0425] [Citation(s) in RCA: 273] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Biologic scaffolds composed of extracellular matrix (ECM) are utilized in numerous regenerative medicine applications to facilitate the constructive remodeling of tissues and organs. The mechanisms by which the host remodeling response occurs are not fully understood, but recent studies suggest that both constituent growth factors and biologically active degradation products derived from ECM play important roles. The objective of the present study was to determine if degradation of ECM scaffold materials in vitro by methods that are biochemically and physiologically relevant can yield products that possess chemotactic and/or mitogenic activities for fully differentiated mammalian endothelial cells and undifferentiated multipotential progenitor cells. ECM harvested from porcine urinary bladder was degraded enzymatically with pepsin/hydrochloric acid or papain. The ECM degradation products were tested for chemoattractant properties utilizing either 48-well chemotaxis filter migration microchambers or fluorescence-based filter migration assays, and were tested for mitogenic properties in cell proliferation assays. Results showed that ECM degradation products possessed chemotactic and mitogenic activities for multipotential progenitor cells and that the same degradation products inhibited both chemotaxis and proliferation of differentiated endothelial cells. These findings support the concept that degradation products of ECM bioscaffolds are important modulators of the recruitment and proliferation of appropriate cell types during the process of ECM scaffold remodeling.
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Affiliation(s)
- Janet E Reing
- Department of Surgery, McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA
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138
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Wang Y, Sul HS. Pref-1 regulates mesenchymal cell commitment and differentiation through Sox9. Cell Metab 2009; 9:287-302. [PMID: 19254573 PMCID: PMC2673480 DOI: 10.1016/j.cmet.2009.01.013] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2008] [Revised: 12/01/2008] [Accepted: 01/30/2009] [Indexed: 01/29/2023]
Abstract
Pref-1 is an EGF repeat-containing transmembrane protein that produces a biologically active soluble form by TACE-mediated cleavage. Although Pref-1 inhibition of adipogenesis has been well established, the specific target(s) of Pref-1 or the Pref-1 function in mesenchymal cell commitment/differentiation are not known. Here, we show that Sox9 downregulation is required for adipocyte differentiation and that Pref-1 inhibits adipocyte differentiation through upregulating Sox9 expression. Sox9 directly binds to the promoter regions of C/EBPbeta and C/EBPdelta to suppress their promoter activity, preventing adipocyte differentiation. Furthermore, we also show that, by inducing Sox9, Pref-1 promotes chondrogenic induction of mesenchymal cells but prevents chondrocyte maturation as well as osteoblast differentiation, with supporting in vivo evidence in Pref-1 null and Pref-1 transgenic mice. Thus, Sox9 is a Pref-1 target, and Pref-1 directs multipotent mesenchymal cells to the chondrogenic lineage but inhibits differentiation into adipocytes as well as osteoblasts and chondrocytes.
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Affiliation(s)
- Yuhui Wang
- Department of Nutritional Science and Toxicology, University of California, Berkeley, Berkeley, CA 94720, USA
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139
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Gene dosage effects of the imprinted delta-like homologue 1 (dlk1/pref1) in development: implications for the evolution of imprinting. PLoS Genet 2009; 5:e1000392. [PMID: 19247431 PMCID: PMC2640098 DOI: 10.1371/journal.pgen.1000392] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2008] [Accepted: 01/26/2009] [Indexed: 11/29/2022] Open
Abstract
Genomic imprinting is a normal process that causes genes to be expressed according to parental origin. The selective advantage conferred by imprinting is not understood but is hypothesised to act on dosage-critical genes. Here, we report a unique model in which the consequences of a single, double, and triple dosage of the imprinted Dlk1/Pref1, normally repressed on the maternally inherited chromosome, can be assessed in the growing embryo. BAC-transgenic mice were generated that over-express Dlk1 from endogenous regulators at all sites of embryonic activity. Triple dosage causes lethality associated with major organ abnormalities. Embryos expressing a double dose of Dlk1, recapitulating loss of imprinting, are growth enhanced but fail to thrive in early life, despite the early growth advantage. Thus, any benefit conferred by increased embryonic size is offset by postnatal lethality. We propose a negative correlation between gene dosage and survival that fixes an upper limit on growth promotion by Dlk1, and we hypothesize that trade-off between growth and lethality might have driven imprinting at this locus. Genomic imprinting, the process that causes genes to be expressed from one of the two chromosome homologues according to parental origin, is likely to act on genes whose dosage is important for their correct function. To test this, we compared the phenotype of transgenic mice expressing a double and triple dose of the imprinted gene Dlk1/Pref1 with animals expressing the normal single dose expressed from the paternally inherited chromosome. Our results showed that a triple dose causes severe developmental abnormalities and death before or at birth. Embryos expressing a double dose, recapitulating absence of imprinting, are bigger at birth but then around one-third of them died within the first three days of life. Those that survived had poor early growth performance in the first week of life becoming small and remaining small, thus offsetting any benefit conferred by being born bigger. Therefore, imprinted levels of Dlk1/Pref1 represent the optimal balance of growth versus lethality. These findings lead to speculation about the evolutionary pressures acting to establish and maintain imprinting at this locus.
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140
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Shin J, Lim S, Latshaw JD, Lee K. Cloning and expression of delta-like protein 1 messenger ribonucleic acid during development of adipose and muscle tissues in chickens. Poult Sci 2009; 87:2636-46. [PMID: 19038821 DOI: 10.3382/ps.2008-00189] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Delta-like protein 1 (DLK1) is involved in adipose and muscle development as shown by the reduction of fat mass in DLK1 transgenic mice and in muscle hypertrophy of callipyge sheep. However, no study on DLK1 has been investigated in avian species. Cloning and sequencing of a full length of chicken DLK1 (gDLK1) complementary DNA revealed that gDLK1 contains a total of 1,161 bp, encoding 386 amino acids. The similarity of gDLK1 nucleotide and protein sequences was over 50% compared with other mammalian species. In addition, chickens only express one full length of gDLK1 in various tissues at different ages without the alternative splicing variants of DLK1 found in mammalian species. This suggests that the full-length form of gDLK1 may be sufficient for normal development in the chicken. In adipose tissue, the gDLK1 gene was highly expressed in preadipocytes as compared with adipocytes (P < 0.05), whereas expression levels of adipogenic marker genes such as stearoyl-coenzyme A desaturase 1 (SCD-1) and fatty acid binding protein 4 (FABP4) were higher in mature adipocytes than in preadipocytes (P < 0.05 and P < 0.01, respectively). Expression of gDLK1 in adipose tissue tends to decrease with age. The expression of gDLK1 gene in the pectoralis major muscle was significantly higher in 13- and 17-d-old embryos (P < 0.05), decreased in 1- and 5-d-old chicks (P < 0.05), and further decreased in 11- and 33-d-old chickens (P < 0.05). This expression pattern of gDLK1 was very similar to the expression patterns of myogenin and Pax7 genes, suggesting a close association with myogenic activities. In conclusion, the developmental regulation of gDLK1 expression might play an important role in the early stages of adipose and muscle tissue development.
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Affiliation(s)
- J Shin
- Department of Animal Sciences, The Ohio State University Interdisciplinary Human Nutrition Program, Columbus 43210, USA
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141
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Mechanical stimulation of mesenchymal stem cell proliferation and differentiation promotes osteogenesis while preventing dietary-induced obesity. J Bone Miner Res 2009; 24:50-61. [PMID: 18715135 PMCID: PMC2689082 DOI: 10.1359/jbmr.080817] [Citation(s) in RCA: 206] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Mesenchymal stem cells (MSCs) are defined by their ability to self-renew and differentiate into the cells that form mesodermal tissues such as bone and fat. Low magnitude mechanical signals (LMMS) have been shown to be anabolic to bone and have been recently reported to suppress the development of fat in normal animals fed a regular diet. Using male C57BL/6J mice, the ability of LMMS (0.2g, 90-Hz signal applied for 15 min/d, 5 d/wk) to simultaneously promote bone formation and prevent diet-induced obesity was correlated to mechanical influences on the molecular environment of the bone marrow, as indicated by the population dynamics and lineage commitment of MSCs. Six weeks of LMMS increased the overall marrow-based stem cell population by 37% and the number of MSCs by 46%. Concomitant with the increase in stem cell number, the differentiation potential of MSCs in the bone marrow was biased toward osteoblastic and against adipogenic differentiation, as reflected by upregulation of the transcription factor Runx2 by 72% and downregulation of PPARgamma by 27%. The phenotypic impact of LMMS on MSC lineage determination was evident at 14 wk, where visceral adipose tissue formation was suppressed by 28%, whereas trabecular bone volume fraction in the tibia was increased by 11%. Translating this to the clinic, a 1-yr trial in young women (15-20 yr; n = 48) with osteopenia showed that LMMS increased trabecular bone in the spine and kept visceral fat at baseline levels, whereas control subjects showed no change in BMD, yet an increase in visceral fat. Mechanical modulation of stem cell proliferation and differentiation indicates a unique therapeutic target to aid in tissue regeneration and repair and may represent the basis of a nonpharmacologic strategy to simultaneously prevent obesity and osteoporosis.
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142
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Orr B, Grace OC, Vanpoucke G, Ashley GR, Thomson AA. A role for notch signaling in stromal survival and differentiation during prostate development. Endocrinology 2009; 150:463-72. [PMID: 18801907 DOI: 10.1210/en.2008-0383] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Notch1 signaling is involved in epithelial growth and differentiation of prostate epithelia, and we have examined the role that notch signaling plays in the stroma of the developing prostate. We initially observed expression of delta-like 1 (Dlk1) and Notch2 in gene profiling studies of prostatic mesenchyme, and anticipated that they might be expressed in a key subset of inductive mesenchyme. Using quantitative RT-PCR, Northern blotting, and whole mount in situ hybridization, we confirmed that both Dlk1 and Notch2 mRNAs showed a restricted expression pattern within subsets of the stroma during prostate development. Localization of Dlk1 and Notch2 proteins mirrored the transcript expression, and showed both distinct and overlapping expression patterns within the stroma. Dlk1 and Notch2 were coexpressed in condensed inductive mesenchyme of the ventral mesenchymal pad (VMP), and were partially colocalized in the smooth muscle (SM) layer of the urethral stroma. In addition, Dlk1 was not expressed in SM adjacent to the VMP in female urethra. The function of notch signaling was examined using organ cultures of prostate rudiments and a small molecule inhibitor of notch receptor activity. Inhibition of notch signaling led to a loss of stromal tissue in both prostate and female VMP cultures, suggesting that this pathway was required for stromal survival. Inhibition of notch signaling also led to changes in both epithelial and stromal differentiation, which was evident in altered distributions of SM alpha-actin and p63 in prostates grown in vitro. The effects of notch signaling upon the stroma were only evident in the presence of testosterone, in contrast to effects upon epithelial differentiation.
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Affiliation(s)
- Brigid Orr
- Medical Research Council Human Reproductive Sciences Unit, Centre for Reproductive Biology, The Queen's Medical Research Institute, Little France Crescent, Edinburgh EH16 4TJ, United Kingdom
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143
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Comparison between genetic portraits of osteoblasts derived from primary cultures and osteoblasts obtained from human pulpar stem cells. J Craniofac Surg 2008; 19:616-25; discussion 626-7. [PMID: 18520373 DOI: 10.1097/scs.0b013e31816aabc8] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Harvesting bone for autologous grafting is a daily problem encountered by craniofacial and oral surgeons. Stem cells derived from human dental pulp are able to differentiate in osteoblasts and are a potential source of autologous bone produced in vitro. However, as stem cells are characterized by self-renewing and commitment in several cellular subtypes (ie, pluripotential differentiation), some concerns may arise as regards their potential uncontrolled proliferation. To screen the behavior of osteoblasts derived from human pulpar stem cells (ODHPSCs), we used microarray techniques to identify genes that are differently regulated in ODHPSC in comparison to normal osteoblasts (NOs). Osteoblasts derived from human pulpar stem cells were obtained from human dental pulp, and cells were selected using a cytometer. The cell profile was c-kit+/CD34+/STRO-1+/CD45-. These cells were capable of differentiation of osteoblasts in vitro. By using DNA microarrays containing 19,200 genes, we identified in ODHPSC some genes whose expression was significantly up- and downregulated compared to NO. The differentially expressed genes have different functional activities: (a) cell differentiation, (b) developmental maturation, (c) cell adhesion, and (d) production of cytoskeleton elements. Thus, some molecular differences exist between NO and ODHPSC, although the previously considered histologic parameters show a normal phenotype.
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144
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Ponce ML, Koelling S, Kluever A, Heinemann DEH, Miosge N, Wulf G, Frosch KH, Schütze N, Hufner M, Siggelkow H. Coexpression of osteogenic and adipogenic differentiation markers in selected subpopulations of primary human mesenchymal progenitor cells. J Cell Biochem 2008; 104:1342-55. [PMID: 18286543 DOI: 10.1002/jcb.21711] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Knowledge of the basic mechanisms controlling osteogenesis and adipogenesis might provide new insights into the prevention of osteoporosis and age-related osteopenia. With the help of magnetic cell sorting and fluorescence activated cell sorting (FACS), osteoblastic subpopulations of mesenchymal progenitor cells were characterized. Alkaline phosphatase (AP) negative cells expressed low levels of osteoblastic and adipocytic markers. AP positive cells expressed adipocytic markers more strongly than the AP negative cell populations, thus suggesting that committed osteoblasts exhibit a greater adipogenic potential. AP negative cells differentiated to the mature osteoblastic phenotype, as demonstrated by increased AP-activity and osteocalcin secretion under standard osteogenic culture conditions. Surprisingly, this was accompanied by increased expression of adipocytic gene markers such as peroxisome proliferator-activated receptor-gamma2, lipoprotein lipase and fatty acid binding protein. The induction of adipogenic markers was suppressed by transforming growth factor-beta1 (TGF-beta1) and promoted by bone morphogenetic protein 2 (BMP-2). Osteogenic culture conditions including BMP-2 induced both the formation of mineralized nodules and cytoplasmic lipid vacuoles. Upon immunogold electron microscopic analysis, osteoblastic and adipogenic marker proteins were detectable in the same cell. Our results suggest that osteogenic and adipogenic differentiation in human mesenchymal progenitor cells might not be exclusively reciprocal, but rather, a parallel event until late during osteoblast development.
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Affiliation(s)
- M L Ponce
- Department of Gastroenterology and Endocrinology, Georg-August-University Goettingen, Goettingen, Germany
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145
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Hermida C, Garcés C, de Oya M, Cano B, Martínez-Costa OH, Rivero S, García-Ramírez JJ, Laborda J, Aragón JJ. The serum levels of the EGF-like homeotic protein dlk1 correlate with different metabolic parameters in two hormonally different children populations in Spain. Clin Endocrinol (Oxf) 2008; 69:216-24. [PMID: 18248640 DOI: 10.1111/j.1365-2265.2008.03170.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
BACKGROUND The Dlk1 gene encodes for dlk1, a transmembrane protein belonging to the EGF-like repeat-containing family. Dlk1 has been shown to act as a regulator of adipogenesis. Fc-dlk1 transgenic mice show a decrease in adipose tissue and glucose tolerance, hypertriglyceridaemia and lower insulin sensitivity. Dlk1-deficient mice show growth retardation, increased serum lipid metabolites and develop obesity. These data advocate for a role of dlk1 in the maintenance of lipid homeostasis, and suggest that dlk1 levels may influence the development of cardiovascular disease. AIM AND METHODS In this study, we analysed whether dlk1 serum levels could be indicative of the different hormonal or metabolic status shown by two Spanish children populations (6-8 years-old), Orense and Murcia. We determined dlk1 serum levels by ELISA assay, using an antibody raised against the recombinant protein, and performed a correlation analysis against measurements of several hormonal and biochemical parameters in samples from 494 subjects. RESULTS We found a statistically significant positive correlation between serum levels of dlk1 and those of glucose (P < 0.05), total cholesterol (P < 0.01) and high-density lipoprotein-cholesterol (HDL-C) (P < 0.01) in children from Murcia, but not from Orense's population, where dehydroepiandrosterone-sulphate (DHEA-S) levels were significantly higher (P < 0.01) and dlk1 correlated positively with insulin (P < 0.01), homeostasis model assessment (HOMA) (P < 0.01) and free fatty acids (FFA) (P < 0.05). CONCLUSIONS dlk1 serum levels appear related to the anabolic status of the children in association with changes in the levels of DHEA-S, which have been associated with hyperinsulinaemia and diabetes. Monitoring dlk1 levels may be important to evaluate the metabolic and hormonal stage of child development.
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Affiliation(s)
- Carmen Hermida
- Departamento de Bioquímica de la UAM, and Instituto de Investigaciones Biomédicas Alberto Sols UAM-CSIC, Facultad de Medicina de la Universidad Autónoma de Madrid, 28029. Madrid, Spain
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146
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Osteoblastic cells: Differentiation and trans-differentiation. Arch Biochem Biophys 2008; 473:183-7. [DOI: 10.1016/j.abb.2008.03.028] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2008] [Revised: 03/16/2008] [Accepted: 03/18/2008] [Indexed: 11/19/2022]
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147
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Human serum levels of fetal antigen 1 (FA1/Dlk1) increase with obesity, are negatively associated with insulin sensitivity and modulate inflammation in vitro. Int J Obes (Lond) 2008; 32:1122-9. [PMID: 18392037 DOI: 10.1038/ijo.2008.40] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE To investigate fetal antigen 1 (FA1) protein within the context of human obesity and its relation with insulin sensitivity. SUBJECTS Cross-sectional study that analyses circulating levels of FA1 in two selected human cohorts: n=127 men for the study of FA1 circulating levels in the context of obesity and insulin sensitivity (S(i)); and n=61 severely obese women before and after bariatric surgery. The response in vitro to FA1 protein on human cell lines of monocytes, preadipocytes and mature adipocytes was studied. MEASUREMENTS Anthropometrical parameters: body mass index, waist-to-hip ratio, waist circumference, fat-free mass and fat mass. Clinical parameters: lipid profile (high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol, total cholesterol, triglycerides), glycemic profile (fasting glucose, insulin, S(i), HOMA-IR (Homeostasis Model Assessment of Insulin Resistance), cytokines (sIL-6), adipokines (adiponectin) and circulating soluble fractions of tumor necrosis factor-alpha receptors 1 and 2 (sTNFR1 and sTNFR2). RESULTS IN the obesity study, levels of FA1 in serum were found to increase with obesity. The S(i) index was negatively dependent on FA1 levels. In severe obesity, serum levels of FA1 decreased 1.4-fold 6 months after bariatric surgery. In vitro assays with FA1 protein on human monocytes and adipocytes cell lines modified the expression of pro-inflammatory cytokines and adipokines (tumor necrosis factor-alpha (TNFalpha), monocyte chemoattractant protein-1 (MCP-1), IL-6 (interleukin-6) and adiponectin). CONCLUSION FA1 serum levels were increased in obese subjects and might influence S(i). The stimulatory effect of FA1 protein on pro-inflammatory cytokines on both immune and adipose cell types could contribute to worsening the inflammatory environment observed in obesity.
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148
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Ceder JA, Jansson L, Helczynski L, Abrahamsson PA. Delta-like 1 (Dlk-1), a novel marker of prostate basal and candidate epithelial stem cells, is downregulated by notch signalling in intermediate/transit amplifying cells of the human prostate. Eur Urol 2008; 54:1344-53. [PMID: 18375047 DOI: 10.1016/j.eururo.2008.03.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2007] [Accepted: 03/07/2008] [Indexed: 10/22/2022]
Abstract
BACKGROUND There is a lack of understanding of the processes that regulate differentiation in the prostate. OBJECTIVE To determine localisation, activity, and regulation of cytodifferentiation-modulatory proteins in the human adult prostate. DESIGN, SETTINGS, AND PARTICIPANTS Eighteen volunteering patients with organ-confined prostate cancer were prospectively enrolled at a single university hospital. INTERVENTION All patients underwent radical prostatectomy, and normal/benign tissue was excised and obtained from the transition zone. MEASUREMENTS Expression and activity of Notch-protein family members, including the Notch-homologous protein Delta-like 1 (Dlk-1/Pref1), were investigated immunohistochemically in normal/benign tissue and explant cultures. The effect of the Notch inhibitor L-685,458 on Dlk-1 expression and cell number was investigated in primary cell cultures, and data were analysed with Student t test. RESULTS AND LIMITATIONS Mature luminal cells were found to co-express Notch-1 and its ligand Jagged1, but epithelia in normal/benign tissue showed no active Notch signalling. The basal cell layer, rare candidate epithelial stem cells, and a subpopulation of neuroendocrine cells expressed the differentiation protein Dlk-1. In explant cultures, luminal cells and Jagged1 expression were lost, whereas intermediate cells downregulated Dlk-1 concomitant with Notch-1 upregulation and activation. Notch inhibition in primary cell cultures led to lower cell densities (p<0.001) and suppressed downregulation of Dlk-1. This is a small study; current results need to be confirmed in larger investigations. CONCLUSIONS We demonstrate that Notch-1 is upregulated in differentiation of prostate epithelia, and that the novel prostate progenitor marker Dlk-1 is downregulated by Notch signalling in intermediate cells. The identification of Dlk-1-expressing candidate stem and neuroendocrine cells suggests a hierarchical relationship.
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Affiliation(s)
- Jens A Ceder
- Lund University, Department of Clinical Sciences, Division of Urological Research, University Hospital MAS, Malmö, Sweden.
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149
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Crespi B. Turner syndrome and the evolution of human sexual dimorphism. Evol Appl 2008; 1:449-61. [PMID: 25567727 PMCID: PMC3352375 DOI: 10.1111/j.1752-4571.2008.00017.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 01/17/2008] [Indexed: 12/17/2022] Open
Abstract
Turner syndrome is caused by loss of all or part of an X chromosome in females. A series of recent studies has characterized phenotypic differences between Turner females retaining the intact maternally inherited versus paternally inherited X chromosome, which have been interpreted as evidence for effects of X-linked imprinted genes. In this study I demonstrate that the differences between Turner females with a maternal X and a paternal X broadly parallel the differences between males and normal females for a large suite of traits, including lipid profile and visceral fat, response to growth hormone, sensorineural hearing loss, congenital heart and kidney malformations, neuroanatomy (sizes of the cerebellum, hippocampus, caudate nuclei and superior temporal gyrus), and aspects of cognition. This pattern indicates that diverse aspects of human sex differences are mediated in part by X-linked genes, via genomic imprinting of such genes, higher rates of mosaicism in Turner females with an intact X chromosome of paternal origin, karyotypic differences between Turner females with a maternal versus paternal X chromosome, or some combination of these phenomena. Determining the relative contributions of genomic imprinting, karyotype and mosaicism to variation in Turner syndrome phenotypes has important implications for both clinical treatment of individuals with this syndrome, and hypotheses for the evolution and development of human sexual dimorphism.
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Affiliation(s)
- Bernard Crespi
- Department of Biosciences, Simon Fraser University Burnaby, BC, Canada
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150
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Developmental, hormonal, and nutritional regulation of porcine adipose triglyceride lipase (ATGL). Lipids 2008; 43:215-25. [PMID: 18189154 DOI: 10.1007/s11745-007-3146-1] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2007] [Accepted: 12/06/2007] [Indexed: 10/22/2022]
Abstract
Adipose triglyceride lipase (ATGL) is a newly identified lipase. We report for the first time the porcine ATGL sequence and characterize ATGL gene and protein expression in vitro and in vivo. Adult pig tissue expresses ATGL at high levels in the white adipose and muscle tissue relative to other tested tissues. We show that within the white adipose tissue ATGL is expressed at higher levels in the adipocyte than in the stromal-vascular fraction. Additionally, ATGL expression increases dramatically in the subcutaneous adipose during adipose development and maturation, as well as during in vitro adipogenesis. Peroxisome proliferator-activated receptor gamma transcript levels increased concomitant with ATGL gene expression, suggesting a possible role in the regulation of ATGL by adipogenic regulators. In vitro treatment of differentiated primary pig preadipocytes with insulin and forskolin decreased ATGL gene expression in a dose-dependent manner, suggesting ATGL transcript levels are hormone sensitive. In vivo experimentation showed that calorie-restriction in gilts resulted in increased ATGL mRNA and protein levels in subcutaneous and peri-renal fat tissues. Our data demonstrate that ATGL expression reacts to hormonal stimuli and plays a role in catecholamine-induced lipolysis in porcine adipose tissue.
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