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Højland AT, Tavernier LJM, Schrauwen I, Sommen M, Topsakal V, Schatteman I, Dhooge I, Huber A, Zanetti D, Kunst HPM, Hoischen A, Petersen MB, Van Camp G, Fransen E. A wide range of protective and predisposing variants in aggrecan influence the susceptibility for otosclerosis. Hum Genet 2021; 141:951-963. [PMID: 34410490 DOI: 10.1007/s00439-021-02334-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 08/04/2021] [Indexed: 12/16/2022]
Abstract
In this study, we investigated the association of ACAN variants with otosclerosis, a frequent cause of hearing loss among young adults. We sequenced the coding, 5'-UTR and 3'-UTR regions of ACAN in 1497 unrelated otosclerosis cases and 1437 matched controls from six different subpopulations. The association between variants in ACAN and the disease risk was tested through single variant and gene-based association tests. After correction for multiple testing, 14 variants were significantly associated with otosclerosis, ten of which represented independent association signals. Eight variants showed a consistent association across all subpopulations. Allelic odds ratios of the variants identified four predisposing and ten protective variants. Gene-based tests showed an association of very rare variants in the 3'-UTR with the phenotype. The associated exonic variants are all located in the CS domain of ACAN and include both protective and predisposing variants with a broad spectrum of effect sizes and population frequencies. This includes variants with strong effect size and low frequency, typical for monogenic diseases, to low effect size variants with high frequency, characteristic for common complex traits. This single-gene allelic spectrum with both protective and predisposing alleles is unique in the field of complex diseases. In conclusion, these findings are a significant advancement to the understanding of the etiology of otosclerosis.
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Affiliation(s)
- Allan Thomas Højland
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Research and Knowledge Center in Sensory Genetics, Department of Clinical Genetics, Aalborg University Hospital, Aalborg, Denmark
| | - Lisse J M Tavernier
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Department of Neurology, Gertrude H. Sergievsky Center, Columbia University Medical Center, New York, NY, USA
| | - Manou Sommen
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium
| | - Vedat Topsakal
- Department of ORL and Head and Neck Surgery, Antwerp University Hospital, University of Antwerp, Edegem, Belgium
| | - Isabelle Schatteman
- European Institute for ORL, St-Augustinus Hospital Antwerp, Antwerp, Belgium
| | - Ingeborg Dhooge
- Department of Otolaryngology, Ghent University Hospital, Ghent, Belgium
| | - Alex Huber
- Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital Zurich, Zurich, Switzerland
| | - Diego Zanetti
- Department of Clinical Sciences and Community Health, Audiology Unit, University of Milan, I.R.C.C.S. Fondazione "Cà Granda", Osp.Le Maggiore Policlinico, Milano, Italy
| | - Henricus P M Kunst
- Department of Otorhinolaryngology, Radboud University Medical Center, Radboud Institute for Health Sciences, Nijmegen, The Netherlands.,Department of Otorhinolaryngology, Maastricht University Medical Centre, Maastricht, The Netherlands
| | - Alexander Hoischen
- Department of Human Genetics, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Otorhinolaryngology, Hearing and Genes, Radboud University Medical Center, Nijmegen, The Netherlands.,Department of Internal Medicine and Radboud Center for Infectious Diseases (RCI), Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michael B Petersen
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark.,Research and Knowledge Center in Sensory Genetics, Department of Clinical Genetics, Aalborg University Hospital, Aalborg, Denmark
| | - Guy Van Camp
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium.
| | - Erik Fransen
- Center of Medical Genetics, University of Antwerp and Antwerp University Hospital, Antwerp, Belgium. .,StatUa Center for Statistics, University of Antwerp, Antwerp, Belgium.
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Kanakis I, Alhashmi M, Liu K, Keenan C, Ramos Mucci L, Poulet B, Bou-Gharios G. Cartilage-Specific Cre Recombinase Transgenes/Alleles in the Mouse. Methods Mol Biol 2021; 2245:23-38. [PMID: 33315193 DOI: 10.1007/978-1-0716-1119-7_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Cartilage is a specialized skeletal tissue with a unique extracellular matrix elaborated by its resident cells, chondrocytes. The tissue presents in several forms, including growth plate and articular cartilage, wherein chondrocytes follow a differential differentiation program and have different fates. The induction of gene modifications in cartilage specifically relies on mouse transgenes and knockin alleles taking advantages of transcriptional elements primarily active in chondrocytes at a specific differentiation stage or in a specific cartilage type. These transgenes/alleles have been widely used to study the roles of specific genes in cartilage development, adult homeostasis, and pathology. As cartilage formation is critical for postnatal life, the inactivation or significant alteration of key cartilaginous genes is often neonatally lethal and therefore hampers postnatal studies. Gold standard approaches to induce postnatal chondrocyte-specific gene modifications include the Cre-loxP and Tet-ON/OFF systems. Selecting the appropriate promoter/enhancer sequences to drive Cre expression is of crucial importance and determines the specificity of conditional gain- or loss-of-function models. In this chapter, we discuss a series of transgenes and knockin alleles that have been developed for gene manipulation in cartilage and we compare their expression patterns and efficiencies.
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Affiliation(s)
- Ioannis Kanakis
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Mohammad Alhashmi
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Ke Liu
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Craig Keenan
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Lorenzo Ramos Mucci
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - Blandine Poulet
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK
| | - George Bou-Gharios
- Department of Musculoskeletal and Ageing Science, Institute of Life Course and Medical Sciences, University of Liverpool, Liverpool, UK.
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Srisuthtayanont W, Pruksakorn D, Kongtawelert P, Pothacharoen P. Effects of sesamin on chondroitin sulfate proteoglycan synthesis induced by interleukin-1beta in human chondrocytes. BMC COMPLEMENTARY AND ALTERNATIVE MEDICINE 2017; 17:286. [PMID: 28569157 PMCID: PMC5452607 DOI: 10.1186/s12906-017-1805-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 05/24/2017] [Indexed: 12/11/2022]
Abstract
Background Numerous studies have reported on the health benefits of sesamin, a major lignin found in sesame (S. indicum) seeds. Recently, sesamin was shown to have the ability to promote chondroitin sulfate proteoglycan synthesis in normal human chondrocytes. This study assesses the anti-inflammatory effect of sesamin on proteoglycans production in 3D chondrocyte cultures. Methods To evaluate the effects of sesamin on IL-1β-treated human articular chondrocytes (HAC) pellets, the pellets were pre-treated with IL-1β then cultured in the presence of various concentrations of sesamin for 21 days. During that period, the expression of IL-1β, glycosaminoglycans (GAGs) content and Chondroitin sulfate proteoglycans (CSPGs) synthesis genes (ACAN, XT-1, XT-2, CHSY1 and ChPF) was measured. The GAGs accumulation in the extracellular matrix was determined on day 21 by histological analysis. Results There was clear evidence that sesamin upregulated expression of all the CSPGs synthesis genes, in contrast to the down-regulation of IL-1β expression both in genes and in protein levels. The level of release and matrix accumulation of GAGs in IL-1β pre-treated HAC pellets in the presence of sesamin was recovered. These results correlate with the histological examination which showed that sesamin enhanced matrix CSPGs accumulation. Conclusions Sesamin enhances CSPGs synthesis, suppresses IL-1β expression and ameliorates IL-1β induced inflammation in human chondrocytes. Sesamin could have therapeutic benefits for treating inflammation in osteoarthritis.
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Khair M, Bourhim M, Barré L, Li D, Netter P, Magdalou J, Fournel-Gigleux S, Ouzzine M. Regulation of xylosyltransferase I gene expression by interleukin 1β in human primary chondrocyte cells: mechanism and impact on proteoglycan synthesis. J Biol Chem 2013; 288:1774-84. [PMID: 23223231 PMCID: PMC3548487 DOI: 10.1074/jbc.m112.419887] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2012] [Revised: 11/23/2012] [Indexed: 01/12/2023] Open
Abstract
Xylosyltransferase I (XT-I) is an essential enzyme of proteoglycan (PG) biosynthesis pathway catalyzing the initial and rate-limiting step in glycosaminoglycan chain assembly. It plays a critical role in the regulation of PG synthesis in cartilage; however, little is known about underlying mechanism. Here, we provide evidence that, in human primary chondrocytes, IL-1β regulates XT-I gene expression into an early phase of induction and a late phase of down-regulation. Based on promoter deletions, the region up to -850 bp was defined as a major element of XT-I gene displaying both constitutive and IL-1β-regulated promoter activity. Point mutation and signaling analyses revealed that IL-1β-induced promoter activity is achieved through AP-1 response elements and mediated by SAP/JNK and p38 signaling pathways. Transactivation and chromatin immunoprecipitation assays indicated that AP-1 is a potent transactivator of XT-I promoter and that IL-1β-induced activity is mediated through increased recruitment of AP-1 to the promoter. Finally, we show that Sp3 is a repressor of XT-I promoter and bring evidence that the repressive effect of IL-1β during the late phase is mediated through Sp3 recruitment to the promoter. This suggests that modulation of Sp3 in cartilage could prevent IL-1β inhibition of PG synthesis and limit tissue degradation.
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Affiliation(s)
- Mostafa Khair
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - Mustapha Bourhim
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - Lydia Barré
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - Dong Li
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - Patrick Netter
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - Jacques Magdalou
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - Sylvie Fournel-Gigleux
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
| | - Mohamed Ouzzine
- From the UMR 7561 CNRS, Faculty of Medicine, University of Lorraine, 54505 Vandœuvre-lès-Nancy, France
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L-Sox5 and Sox6 drive expression of the aggrecan gene in cartilage by securing binding of Sox9 to a far-upstream enhancer. Mol Cell Biol 2008; 28:4999-5013. [PMID: 18559420 DOI: 10.1128/mcb.00695-08] [Citation(s) in RCA: 229] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The Sry-related high-mobility-group box transcription factor Sox9 recruits the redundant L-Sox5 and Sox6 proteins to effect chondrogenesis, but the mode of action of the trio remains unclear. We identify here a highly conserved 359-bp sequence 10 kb upstream of the Agc1 gene for aggrecan, a most essential cartilage proteoglycan and key marker of chondrocyte differentiation. This sequence directs expression of a minimal promoter in both embryonic and adult cartilage in transgenic mice, in a manner that matches Agc1 expression. The chondrogenic trio is required and sufficient to mediate the activity of this enhancer. It acts directly, Sox9 binding to a critical cis-acting element and L-Sox5/Sox6 binding to three additional elements, which are cooperatively needed. Upon binding to their specific sites, L-Sox5/Sox6 increases the efficiency of Sox9 binding to its own recognition site and thereby robustly potentiates the ability of Sox9 to activate the enhancer. L-Sox5/Sox6 similarly secures Sox9 binding to Col2a1 (encoding collagen-2) and other cartilage-specific enhancers. This study thus uncovers critical cis-acting elements and transcription factors driving Agc1 expression in cartilage and increases understanding of the mode of action of the chondrogenic Sox trio.
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Abstract
Once articular cartilage is injured, it has a very limited capacity for self repair. Although current surgical therapeutic procedures for cartilage repair are clinically useful, they cannot restore a normal articular surface. Current research offers a growing number of bioactive reagents, including proteins and nucleic acids, that may be used to augment various aspects of the repair process. As these agents are difficult to administer effectively, gene-transfer approaches are being developed to provide their sustained synthesis at sites of repair. To augment regeneration of articular cartilage, therapeutic genes can be delivered to the synovium or directly to the cartilage lesion. Gene delivery to the cells of the synovial lining is generally considered more suitable for chondroprotective approaches, based on the expression of anti-inflammatory mediators. Gene transfer targeted at cartilage defects can be achieved by either direct vector administration to cells located at or surrounding the defects, or by transplantation of genetically modified chondrogenic cells into the defect. Several studies have shown that exogenous cDNAs encoding growth factors can be delivered locally to sites of cartilage damage, where they are expressed at therapeutically relevant levels. Furthermore, data is beginning to emerge indicating that efficient delivery and expression of these genes is capable of influencing a repair response toward the synthesis of a more hyaline cartilage repair tissue in vivo. This review presents the current status of gene therapy for cartilage healing and highlights some of the remaining challenges.
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Affiliation(s)
- Andre F. Steinert
- Orthopaedic Center for Musculoskeletal Research König-Ludwig-Haus, Julius-Maximilians-University, Würzburg, Germany
| | - Ulrich Nöth
- Orthopaedic Center for Musculoskeletal Research König-Ludwig-Haus, Julius-Maximilians-University, Würzburg, Germany
| | - Rocky S. Tuan
- Cartilage Biology and Orthopaedics Branch National Institute of Arthritis, and Musculoskeletal and Skin Diseases National Institutes of Health, Department of Health and Human Services Bethesda, MD, U.S.A
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7
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Barré L, Venkatesan N, Magdalou J, Netter P, Fournel-Gigleux S, Ouzzine M. Evidence of calcium‐dependent pathway in the regulation of human β1,3‐glucuronosyltransferase‐1 (GlcAT‐I) gene expression: a key enzyme in proteoglycan synthesis. FASEB J 2006; 20:1692-4. [PMID: 16807373 DOI: 10.1096/fj.05-5073fje] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The importance of heparan- and chondroitin-sulfate proteoglycans in physiological and pathological processes led to the investigation of the regulation of beta1,3-glucuronosyltransferase I (GlcAT-I), responsible for the completion of glycosaminoglycan-protein linkage tetrasaccharide, a key step prior to polymerization of chondroitin- and heparan-sulfate chains. We have cloned and functionally characterized GlcAT-I 5'-flanking regulatory region. Mutation analysis and electrophoretic mobility shift assays demonstrated the importance of Sp1 motif located at -65/-56 position in promoter activity. Furthermore, we found that elevation of intracellular calcium concentration by the calcium ionophore ionomycin stimulated GlcAT-I gene expression as well as glycosaminoglycan chain synthesis in HeLa cells. Bisanthracycline, an anti-Sp1 compound, inhibited GlcAT-I basal promoter activity and suppressed ionomycin induction, suggesting the importance of Sp1 in calcium induction of GlcAT-I gene expression. Nuclear protein extracts from ionomycin-induced cells exhibited an increased DNA binding of Sp1 factor to the consensus sequence at position -65/-56. Signaling pathway analysis and MEK inhibition studies revealed the important role of p42/p44 MAPK in the stimulation of GlcAT-I promoter activity by ionomycin. The present study identifies, for the first time, GlcAT-I as a target of calcium-dependent signaling pathway and evidences the critical role of Sp1 transcription factor in the activation of GlcAT-I expression.
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Affiliation(s)
- Lydia Barré
- UMR CNRS 7561-Université Henri Poincaré Nancy 1, Faculté de Médecine, BP 184, Vandoeuvre-lès-Nancy 54505, France
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8
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Lee YC, Higashi Y, Luu C, Shimizu C, Strott CA. Sp1 elements inSULT2B1bpromoter and 5′-untranslated region of mRNA: Sp1/Sp2 induction and augmentation by histone deacetylase inhibition. FEBS Lett 2005; 579:3639-45. [PMID: 15953604 DOI: 10.1016/j.febslet.2005.05.041] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2005] [Revised: 05/23/2005] [Accepted: 05/25/2005] [Indexed: 10/25/2022]
Abstract
The steroid/sterol sulfotransferase gene (SULT2B1) encodes for two isozymes of which one (SULT2B1b) sulfonates cholesterol and is selectively expressed in skin. The human SULT2B1 gene contains neither a TATAAA nor a CCAAT motif upstream of the coding region for SULT2B1b; however, this area is GC-rich. Of five Sp1 elements identified two had regulatory activity utilizing immortalized human keratinocytes: one element is located above the ostensible transcription initiation site, whereas the other is located within the 5'-untranslated region of the SULT2B1b mRNA. Sp1 and Sp2 transcription factors identified by supershift analyses induced reporter gene activity, an effect markedly augmented by histone deacetylase inhibition.
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Affiliation(s)
- Young C Lee
- Section on Steroid Regulation, Endocrinology and Reproduction Research Branch, National Institute of Child Health and Human Development, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892-4510, USA
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9
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Sitcheran R, Gupta P, Fisher PB, Baldwin AS. Positive and negative regulation of EAAT2 by NF-kappaB: a role for N-myc in TNFalpha-controlled repression. EMBO J 2005; 24:510-20. [PMID: 15660126 PMCID: PMC548660 DOI: 10.1038/sj.emboj.7600555] [Citation(s) in RCA: 188] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2004] [Accepted: 12/21/2004] [Indexed: 01/15/2023] Open
Abstract
The glutamate transporter gene, EAAT2/GLT-1, is induced by epidermal growth factor (EGF) and downregulated by tumor necrosis factor alpha (TNFalpha). While TNFalpha is generally recognized as a positive regulator of NF-kappaB-dependent gene expression, its ability to control transcriptional repression is not well characterized. Additionally, the regulation of NF-kappaB by EGF is poorly understood. Herein, we demonstrate that both TNFalpha-mediated repression and EGF-mediated activation of EAAT2 expression require NF-kappaB. We show that EGF activates NF-kappaB independently of signaling to IkappaB. Furthermore, TNFalpha can abrogate IKKbeta- and p65-mediated activation of EAAT2. Our results suggest that NF-kappaB can intrinsically activate EAAT2 and that TNFalpha mediates repression through a distinct pathway also requiring NF-kappaB. Consistently, we find that N-myc is recruited to the EAAT2 promoter with TNFalpha and that N-myc-binding sites are required for TNFalpha-mediated repression. Moreover, N-myc overexpression inhibits both basal and p65-induced activation of EAAT2. Our data highlight the remarkable specificity of NF-kappaB activity to regulate gene expression in response to diverse cellular signals and have implications for glutamate homeostasis and neurodegenerative disease.
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Affiliation(s)
- Raquel Sitcheran
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, NC, USA
| | - Pankaj Gupta
- Department of Pathology, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY, USA
| | - Paul B Fisher
- Department of Pathology, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY, USA
- Departments of Neurosurgery and Urology, College of Physicians and Surgeons, Columbia University Medical Center, New York, NY, USA
| | - Albert S Baldwin
- Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, NC, USA
- Department of Biology, University of North Carolina at Chapel Hill, NC, USA
- 22-000 Lineberger Comprehensive Cancer Center, CB#7295, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-7295, USA. Tel.: +1 919 966 3652; Fax: +1 919 966 0444; E-mail: or
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10
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Alford AI, Yellowley CE, Jacobs CR, Donahue HJ. Increases in cytosolic calcium, but not fluid flow, affect aggrecan mRNA levels in articular chondrocytes. J Cell Biochem 2004; 90:938-44. [PMID: 14624453 DOI: 10.1002/jcb.10715] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Fluctuations in intracellular free calcium concentration ([Ca2+]i) is thought to be one mechanism by which cells transduce mechanical signals into biological responses. Primary cultures of bovine articular chondrocytes (BAC) respond to oscillating fluid flow with a transient rise in [Ca2+]i. However, specific down-stream effects of [Ca2+]i on gene expression and phenotype in BAC remain to be defined. The present work was designed to determine whether [Ca2+]i mobilization regulates aggrecan mRNA levels. [Ca2+]i was transiently elevated by exposing BAC to the [Ca2+]-specific ionophore, ionomycin. The results show that ionomycin increases [Ca2+]i in a dose-dependent fashion. Semi-quantitative real time (RT)-PCR was used to study the effects of increased [Ca2+]i on steady state levels of aggrecan mRNA. Four hours after a brief exposure to 1.5 microM ionomycin, BAC displayed a nearly four-fold decrease in aggrecan mRNA levels compared to control cells. This effect of ionomycin on aggrecan mRNA was no longer evident 6 or 10 h later. Despite previous observations that oscillating fluid flow elicits increased [Ca2+]i in BAC, it did not affect aggrecan mRNA levels. Taken together, these data suggest that ionomycin-induced [Ca2+]i fluctuations regulate aggrecan mRNA levels, but that flow induced [Ca2+]i fluctuations do not.
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Affiliation(s)
- A I Alford
- Musculoskeletal Research Laboratory, Department of Orthopaedics and Rehabilitation, The Pennsylvania State University College of Medicine, Hershey, Pennysylvania 17033, USA
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11
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Sezaki N, Ishimaru F, Tabayashi T, Kataoka I, Nakase K, Fujii K, Kozuka T, Nakayama H, Harada M, Tanimoto M. The type 1 CD10/neutral endopeptidase 24.11 promoter: functional characterization of the 5′-untranslated region. Br J Haematol 2003; 123:177-83. [PMID: 14510963 DOI: 10.1046/j.1365-2141.2003.04574.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cell surface zinc metalloproteinase CD10/neutral endopeptidase 24.11 (NEP) is expressed on normal and malignant lymphoid progenitors, granulocytes and a variety of epithelial cells. Because CD10/NEP functions as part of a regulatory loop that controls local concentrations of peptide substrates and associated peptide-mediated signal transduction, its role in each tissue is different depending on the availability of substrate. To characterize further how this widely distributed molecule is regulated differentially in each tissue, we analysed the major type 2 CD10/NEP promoter and found three functionally important transcription factor binding sites, one of which was identical to CCAAT-binding transcription factor/nuclear transcription factor Y. In this report, we analyse the type 1 CD10/NEP promoter and found a functionally important transcription factor binding site in the 5'-untranslated region. The results of the competition and supershift experiments demonstrated that the functionally important transcription factor was identical to Sp1. Our results suggest that ubiquitously expressed Sp1 may play an important role in differentiation stage-specific regulation of CD10/NEP expression in lymphoid lineage.
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Affiliation(s)
- Nobuo Sezaki
- Department of Medicine, University of Okayama, Okayama, Japan
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12
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Legendre F, Dudhia J, Pujol JP, Bogdanowicz P. JAK/STAT but not ERK1/ERK2 pathway mediates interleukin (IL)-6/soluble IL-6R down-regulation of Type II collagen, aggrecan core, and link protein transcription in articular chondrocytes. Association with a down-regulation of SOX9 expression. J Biol Chem 2003; 278:2903-12. [PMID: 12419823 DOI: 10.1074/jbc.m110773200] [Citation(s) in RCA: 144] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Signal transducers and activators of transcription (STAT) factors are cytoplasmic proteins that can be activated by Janus kinases (JAK) and that modulate gene expression in response to cytokine receptor stimulation. STAT proteins dimerize, translocate into the nucleus, and activate specific target genes. In the present study, we show for the first time that interleukin-6 (IL), in the presence of its soluble receptor (sIL-6R), induces activation of JAK1, JAK2, and STAT1/STAT3 proteins in bovine articular chondrocytes. Western blotting and mobility shift assays demonstrated that this effect is accompanied by the DNA binding of the STAT proteins. The mitogen-activated protein kinase pathway was also activated in response to IL-6/sIL-6R association, as reflected by phosphorylation of ERK1 and ERK2 proteins. In these conditions, the expression of cartilage-specific matrix genes, type II collagen, aggrecan core, and link proteins was found to be markedly down-regulated. This negative effect was abolished by addition of parthenolide, an inhibitor of the STAT activation, whereas blockade of the MAP kinases with PD098059 was without significant effect. Thus, activation of the STAT signaling pathways, but not ERK-dependent pathways, is essential for down-regulation of the major cartilage-specific matrix genes by IL-6. In addition, a parallel reduction of Sox9 expression, a key factor of chondrocyte phenotype, was found in these experimental conditions. These IL-6 effects might contribute to the phenotype loss of chondrocytes in joint diseases and the alteration of articular cartilage associated with this pathology.
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Affiliation(s)
- Florence Legendre
- Laboratoire de Biochimie du Tissu Conjonctif, Faculté de Médecine, 14032 Caen Cedex, France
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13
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Tuli R, Seghatoleslami MR, Tuli S, Howard MS, Danielson KG, Tuan RS. p38 MAP kinase regulation of AP-2 binding in TGF-beta1-stimulated chondrogenesis of human trabecular bone-derived cells. Ann N Y Acad Sci 2002; 961:172-7. [PMID: 12081893 DOI: 10.1111/j.1749-6632.2002.tb03077.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Collagenase-treated, explanted human trabecular-bone chips are an excellent source of osteoblast-like cells. We have recently shown the multiple differentiation potential of these cells; in addition to osteogenesis and adipogenesis, these cells also undergo chondrogenesis when maintained as high-density pellet cultures (250,000 cells/pellet) in a serum-free, chemically defined medium stimulated with TGF-beta1 (10 ng/mL). In this investigation, we have analyzed how transactivating nuclear transcription factors, specifically AP-2 and SP-1, may interact with common cis-acting elements found in the regulatory region of cartilage-specific genes as part of the signal transduction mechanism of TGF-beta1 and p38 during chondrogenesis of human trabecular bone-derived multipotential cells. Both TGF-beta1 stimulation and p38 MAP kinase activation affect the binding of AP-2 as well as SP-1 to oligonucleotides with sequence similarity to the overlapping AP-2/SP-1 sites found in the putative 52-bp immediate upstream regulatory region and the 5'-untranslated region of the human aggrecan gene. Electrophoretic mobility shift assays show that TGF-beta1 treatment of the bone-derived cells inhibits AP-2 DNA binding but enhances the DNA binding ability of SP-1. Additionally, treatment of these TGF-beta1-stimulated cells with p38 MAP kinase inhibitor, SB203580, rescued the AP-2 DNA binding but did not affect SP-1 DNA binding. These findings indicate that AP-2 DNA binding is the target of both TGF-beta1 and p38 MAP kinase signaling pathways and suggest a possible signal transduction cascade whereby TGF-beta1 induction of chondrogenesis involves the activation of p38 MAP kinase and the subsequent inhibition of DNA binding by AP-2, thereby preventing the transcriptional repression of the aggrecan gene.
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Affiliation(s)
- R Tuli
- Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases/NIH, 50 South Drive, Building 50 Room 1503, Bethesda, MD 20892, USA
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Doege K, Hall LB, McKinnon W, Chen L, Stephens DT, Garrison K. A remote upstream element regulates tissue-specific expression of the rat aggrecan gene. J Biol Chem 2002; 277:13989-97. [PMID: 11834732 DOI: 10.1074/jbc.m109627200] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The regulation of chondrogenesis and of the genes expressed as markers of chondrocyte differentiation is poorly understood. The hyaluronan-binding proteoglycan aggrecan is an essential and specific component of cartilage, but the aggrecan proximal promoter is expressed in an unregulated fashion in vitro. DNA comprising the rat aggrecan gene (83 kb including the 30-kb first intron) was surveyed for active elements, which would impart selective expression to the aggrecan promoter in transfection assays in vitro. A 4.7-kb DNA fragment (P3) with cell-specific enhancer activity was discovered approximately 12 kb upstream of the transcription start site; this active DNA fragment is position- and orientation-independent, and strongly stimulates aggrecan promoter expression in chondrocytes, while weakly suppressing transcription in fibroblasts. Most of this activity has been localized to P3-7, a 2.3-kb internal fragment of P3. Another enhancer element (A23), which is not tissue-specific, was discovered about 70 kb downstream of the transcription start site. Several lines of transgenic mice were created using combinations of these DNA elements to drive the lacZ reporter gene. Neither a short (900 bp) nor a long (3.7 kb) promoter alone showed detectable expression in 14.5-day embryos, whereas placing the P3 tissue-specific enhancer together with P0 gave strong expression restricted to embryonic cartilage of transgenic mice. The A23 downstream enhancer in conjunction with P0 did not confer expression. This is the first report of a gene control region which confers authentic tissue-specific regulation of aggrecan in vitro or in vivo and should greatly facilitate understanding the coordinate regulation of chondrocytic genes.
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Affiliation(s)
- Kurt Doege
- Department of Biochemistry, College of Medicine, University of South Florida, Tampa, Florida 33612, USA.
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15
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Landry JR, Medstrand P, Mager DL. Repetitive elements in the 5' untranslated region of a human zinc-finger gene modulate transcription and translation efficiency. Genomics 2001; 76:110-6. [PMID: 11549323 DOI: 10.1006/geno.2001.6604] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A substantial proportion of the human genome consists of repetitive sequences. Although most of these sequences are nonessential for the organism, retroelements, such as Alu sequences, L1s, and HERVs (human endogenous retroviruses), have recently been implicated in the regulation of various genes. Our laboratory previously identified a novel, alternatively spliced zinc-finger gene, ZNF177, which incorporates Alu L1, and HERV segments into the 5' untranslated region (UTR) of transcripts. In this study, we investigated the genomic structure and functional significance of the repetitive sequences in the 5' UTR of ZNF177 mRNAs. Using luciferase and GFP reporter constructs, we assessed the effect of the HERV, Alu, and L1 sequences on gene expression levels. Our results indicate that the presence of the retroelement sequences, particularly the Alu and L1 segments which form one 5' UTR exon, modifies the expression level of both reporter genes. We present evidence that the Alu and L1 sequences alter both the RNA and protein levels of reporter genes by increasing transcription efficiency while decreasing translation efficiency. Our findings indicate that the Alu and L1 repeats in the 5' UTR of ZNF177 exert a positive transcriptional enhancer effect, but repress translation of the zinc finger gene. In addition, our analysis of a 5' UTR database suggests that 4% of human 5' UTRs harbor Alu sequences, indicating that the expression of many genes might be influenced by Alu repeats. These results illustrate the complex regulatory effects that retroelements can have on human gene expression.
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Affiliation(s)
- J R Landry
- Terry Fox Laboratory, British Columbia Cancer Agency and Department of Medical Genetics, University of British Columbia, Vancouver, British Columbia, Canada
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16
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Yanagihara I, Yamagata M, Sakai N, Shukunami C, Kurahashi H, Yamazaki M, Michigami T, Hiraki Y, Ozono K. Genomic organization of the human chondromodulin-1 gene containing a promoter region that confers the expression of reporter gene in chondrogenic ATDC5 cells. J Bone Miner Res 2000; 15:421-9. [PMID: 10750556 DOI: 10.1359/jbmr.2000.15.3.421] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Chondromodulin-1 (ChM-1) is a cartilage-specific glycoprotein that stimulates the growth of chondrocytes and inhibits the tube formation of endothelial cells. To clarify the tissue-specific expression and the role of ChM-1 in pathophysiological conditions, we analyzed the structure of the human ChM-1 gene and its promoter. On the screening of a human genomic cosmid library using the human ChM-1 complimentary DNA (cDNA) as a probe, two clones were obtained that contained ChM-1 cDNA. The restriction enzyme map and nucleotide sequence revealed the human ChM-1 gene consisting of seven exons and exon-intron boundaries. The human ChM-1 gene was assigned to chromosome 13q14-21 by fluorescence in situ hybridization (FISH) using the clone as a probe. A primer extension analysis using total RNA extracted from human cartilage revealed a major transcription start site with the sequence CGCT+1GG. The region approximately 3-kilobase (kb) nucleotides upstream of the translation start site was then sequenced and analyzed in terms of promoter activity. We found that a region 446 base pairs (bp) upstream of the start site had promoter activity in COS7, HeLa, and ATDC5 cells. In structure the promoter is a TATA-less type without a GC-rich region. The transcription factors Sox9, Og12, and Cart-1 did not affect the promoter activity. The transcription factor Ying-Yang1 suppressed the promoter activity but GABP protein did not change the promoter activity. The construct containing -446/+87 fused to the SV40 enhancer and green fluorescent protein (GFP) exhibited expression of GFP corresponding to the differentiation of ATDC5 cells to mature chondrocytes. These results suggest that the element -446/+87 confers the cartilage-specific expression of this gene by some factor(s) other than Sox9, Og12, and Cart-1.
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Affiliation(s)
- I Yanagihara
- Department of Environmental Medicine, Osaka Medical Center and Research Institute for Maternal and Child Health, Japan
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17
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Hung CT, Henshaw DR, Wang CC, Mauck RL, Raia F, Palmer G, Chao PH, Mow VC, Ratcliffe A, Valhmu WB. Mitogen-activated protein kinase signaling in bovine articular chondrocytes in response to fluid flow does not require calcium mobilization. J Biomech 2000; 33:73-80. [PMID: 10609520 DOI: 10.1016/s0021-9290(99)00176-1] [Citation(s) in RCA: 82] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
In the present study, the role of mitogen-activated protein kinases (MAPKs) in chondrocyte mechanotransduction was investigated. We hypothesized that MAPKs participate in fluid flow-induced chondrocyte mechanotransduction. To test our hypothesis, we studied cultured chondrocytes subjected to a well-defined mechanical stimulus generated with a laminar flow chamber. The extracellular signal-regulated kinases 1 and 2 (ERK1/2) were activated 1.6-3-fold after 5-15 min of fluid flow exposure corresponding to a chamber wall shear stress of 1.6 Pa. Activation of ERK1/2 was observed in the presence of both 10% FBS and 0.1% BSA, suggesting that the flow effects do not require serum agonists. Treatment with thapsigargin or EGTA had no significant effect on the ERK1/2 activation response to flow, suggesting that Ca2+ mobilization is not required for this response. To assess downstream effects of the activated MAPKs on transcription, flow studies were performed using chondrocytes transfected with a chimeric luciferase construct containing 2.4 kb of the promoter region along with exon 1 of the human aggrecan gene. Two-hour exposure of transfected chondrocytes to fluid flow significantly decreased aggrecan promoter activity by 40%. This response was blocked by treatment of chondrocytes with the MEK-1 inhibitor PD98059. These findings demonstrate that, under the conditions of the present study, fluid flow-induced signals activate the MEK-1/ERK signaling pathway in articular chondrocytes, leading to down-regulation of expression of the aggrecan gene.
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Affiliation(s)
- C T Hung
- Cellular Engineering Laboratory, Center for Biomedical Engineering, Columbia University, New York, NY 10027, USA
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