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Ferreira E, Gatrell LB, Childress L, Wu H, Porter RM. A Transgenic Rat for Noninvasive Assessment of Chondrogenesis in Vivo. Cartilage 2021; 13:1720S-1733S. [PMID: 34809478 PMCID: PMC8804729 DOI: 10.1177/19476035211057243] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
OBJECTIVE To support the preclinical evaluation of therapeutics that target chondrogenesis, our goal was to generate a rat strain that can noninvasively report endogenous chondrogenic activity. DESIGN A transgene was constructed in which the dual expression of bioluminescent (firefly luciferase) and fluorescent (mCherry) reporters is controlled by regulatory sequences from rat Col2a1. Candidate lines were established on a Lewis background and characterized by serial bioluminescence imaging as well as ex vivo measurement of molecular reporter levels in several tissues. The sensitivity and specificity of the reporter strain were assessed in models of orthotopic and ectopic chondrogenesis. RESULTS Substantial bioluminescence signal was detected from cartilaginous regions, including the appendicular synovial joints, spine, sternum, nose, and pinnae. Bioluminescent radiance was intense at 1 month of age, rapidly declined with continued development, yet remained detectable in 2-year-old animals. Explant imaging and immunohistochemistry confirmed that both molecular reporters were localized to cartilage. Implantation of wild-type bone marrow stromal cells into osteochondral defects made in both young adult and aged reporter rats led to a time-dependent elevation of intra-articular reporter activity concurrent with cartilaginous tissue repair. To stimulate ectopic, endochondral bone formation, bone morphogenetic protein 2 was overexpressed in the gastrocnemius muscle, which led to bioluminescent signal that closely preceded heterotopic ossification. CONCLUSIONS This strain can help develop strategies to stimulate cartilage repair and endochondral bone formation or to inhibit chondrogenesis associated with heterotopic ossification.
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Affiliation(s)
- Elisabeth Ferreira
- Center for Musculoskeletal Disease
Research, Departments of Internal Medicine and Orthopaedic Surgery, University of
Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Landon B. Gatrell
- Center for Musculoskeletal Disease
Research, Division of Endocrinology and Metabolism, Department of Internal Medicine,
University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Luke Childress
- Center for Musculoskeletal Disease
Research, Division of Endocrinology and Metabolism, Department of Internal Medicine,
University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Hong Wu
- Center for Musculoskeletal Disease
Research, Division of Endocrinology and Metabolism, Department of Internal Medicine,
University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Ryan M. Porter
- Center for Musculoskeletal Disease
Research, Departments of Internal Medicine and Orthopaedic Surgery, University of
Arkansas for Medical Sciences, Little Rock, AR, USA,Ryan M. Porter, Center for Musculoskeletal
Disease Research, Departments of Internal Medicine and Orthopaedic Surgery,
University of Arkansas for Medical Sciences, 4301 W. Markham Street, Mail Slot
#587, Little Rock, AR 72202, USA.
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2
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Rhodes CS, Matsunobu T, Yamada Y. Analysis of a limb-specific regulatory element in the promoter of the link protein gene. Biochem Biophys Res Commun 2019; 518:672-677. [PMID: 31470976 PMCID: PMC10505274 DOI: 10.1016/j.bbrc.2019.08.104] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 08/19/2019] [Indexed: 11/30/2022]
Abstract
Link protein is encoded by the Hapln1 gene and is a prototypical protein found in the cartilage matrix. It acts as an important component of the endochondral skeleton during early development. To study its transcriptional regulation, promoter fragments derived from the link protein gene were coupled to the β-galactosidase reporter and used to study in vivo transgene expression in mice. In day 15.5 mouse embryos, a link promoter fragment spanning -1020 to +40 nucleotides demonstrated highly specific β-galactosidase staining of skeletal structures, including the appendicular and axial cartilaginous tissues. Two shorter promoter fragments, spanning -690 to +40 and -315 to +40 nucleotides, demonstrated limb- and genitalia-specific expression resembling that of homeodomain-regulated tissues. Bioinformatic analysis revealed a highly conserved, Hox-like binding site (HLBS) at approximately -220 bp of the promoter, shared by both constructs, which contained the Hox-core consensus sequence TAATTA. Electromobility shift assays demonstrated binding of Hox-B4 recombinant protein to the HLBS, which was eliminated with nucleotide substitutions within the core-binding element. Co-transfection analysis of the HLBS demonstrated a 22-fold transcriptional activation by HoxA9 expression, which was ablated with a substitution within the core HLBS element. Together these findings establish promoter regions within the link protein gene that are important for in vivo expression and identify the potential role of homeodomain-containing proteins in controlling cartilage and limb gene expression.
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Affiliation(s)
- Craig S Rhodes
- Molecular Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA.
| | - Tomoya Matsunobu
- Department of Orthopaedic Surgery, Kyushu Rosai Hospital, 1-1 Sonekitamachi, Kokuraminami-ku, Kitakyushu, Fukuoka, 800-0296, Japan
| | - Yoshihiko Yamada
- Molecular Biology Section, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, 20892, USA
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3
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Ho EYK, Cao Q, Gu M, Chan RWL, Wu Q, Gerstein M, Yip KY. Shaping the nebulous enhancer in the era of high-throughput assays and genome editing. Brief Bioinform 2019; 21:836-850. [PMID: 30895290 DOI: 10.1093/bib/bbz030] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 02/15/2019] [Accepted: 02/26/2019] [Indexed: 01/22/2023] Open
Abstract
Since the 1st discovery of transcriptional enhancers in 1981, their textbook definition has remained largely unchanged in the past 37 years. With the emergence of high-throughput assays and genome editing, which are switching the paradigm from bottom-up discovery and testing of individual enhancers to top-down profiling of enhancer activities genome-wide, it has become increasingly evidenced that this classical definition has left substantial gray areas in different aspects. Here we survey a representative set of recent research articles and report the definitions of enhancers they have adopted. The results reveal that a wide spectrum of definitions is used usually without the definition stated explicitly, which could lead to difficulties in data interpretation and downstream analyses. Based on these findings, we discuss the practical implications and suggestions for future studies.
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Affiliation(s)
| | - Qin Cao
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong
| | - Mengting Gu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA
| | - Ricky Wai-Lun Chan
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong
| | - Qiong Wu
- Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong.,School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong
| | - Mark Gerstein
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut, USA.,Program in Computational Biology and Bioinformatics.,Department of Computer Science, Yale University, New Haven, Connecticut, USA
| | - Kevin Y Yip
- Department of Biomedical Engineering.,Department of Computer Science and Engineering, The Chinese University of Hong Kong, Hong Kong.,Hong Kong Bioinformatics Centre.,CUHK-BGI Innovation Institute of Trans-omics.,Hong Kong Institute of Diabetes and Obesity, The Chinese University of Hong Kong, Hong Kong
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4
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Differential transactivation of the upstream aggrecan enhancer regulated by PAX1/9 depends on SOX9-driven transactivation. Sci Rep 2019; 9:4605. [PMID: 30872687 PMCID: PMC6418084 DOI: 10.1038/s41598-019-40810-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/22/2019] [Indexed: 01/07/2023] Open
Abstract
A previously identified enhancer 10 kb upstream of the Aggrecan (Acan) gene (UE) can drive cartilage specific reporter expression in vivo. Here, we report that the paralogous transcription factors PAX1 and PAX9 differentially drive UE, depending on the presence or absence of SOX9-driven transactivation. In the developing vertebral column, PAX1/9 expression was inversely correlated with Acan expression. Moreover, PAX1/9 was co-expressed with SOX9/5/6 in the intervertebral mesenchyme and the inner annulus fibrosus (AF), and with SOX9 in the outer AF. Significant Acan upregulation was observed during chondrification of Pax1-silenced AF cells, while, Acan was significantly downregulated by persistent expression of Pax1 in cartilage. Deletion of UE using CRISPR/Cas9 resulted in ~30% and ~40% reduction of Acan expression in cartilage and the AF, respectively. In the UE, PAX1/9 acts as weak transactivators through a PAX1/9-binding site partially overlapped with a SOX9-binding site. In the presence of SOX9, which otherwise drives robust Acan expression along with SOX5/6, PAX1/9 competes with SOX9 for occupancy of the binding site, resulting in reduced transactivation of Acan. Coimmunoprecipitation revealed the physical interaction of Pax1 with SOX9. Thus, transactivation of the UE is differentially regulated by concerted action of PAX1/9, SOX9, and SOX5/6 in a context-dependent manner.
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5
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Wang B, Jin H, Shu B, Mira RR, Chen D. Chondrocytes-Specific Expression of Osteoprotegerin Modulates Osteoclast Formation in Metaphyseal Bone. Sci Rep 2015; 5:13667. [PMID: 26329493 PMCID: PMC4556963 DOI: 10.1038/srep13667] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2015] [Accepted: 07/21/2015] [Indexed: 12/21/2022] Open
Abstract
Bone marrow stromal cells/osteoblasts were originally thought to be the major player in regulating osteoclast differentiation through expressing RANKL/OPG cytokines. Recent studies have established that chondrocytes also express RANKL/OPG and support osteoclast formation. Till now, the in vivo function of chondrocyte-produced OPG in osteoclast formation and postnatal bone growth has not been directly investigated. In this study, chondrocyte-specific Opg transgenic mice were generated by using type II collagen promoter. The Col2-Opg transgenic mice showed delayed formation of secondary ossification center and localized increase of bone mass in proximal metaphysis of tibiae. TRAP staining showed that osteoclast numbers were reduced in both secondary ossification center and proximal metaphysis. This finding was further confirmed by in vitro chondrocyte/spleen cell co-culture assay. In contrast, the mineral apposition rates were not changed in Col2-Opg transgenic mice. TUNEL staining revealed more apoptotic hypertrophic chondrocytes in the growth plate of Col2-Opg mice. Flow cytometry analysis showed fewer RANK-expressing cells in the marrow of Col2a1-Opg mice, suggesting the role of OPG in blocking the differentiation of early mesenchymal progenitors into RANK-expressing pre-osteoclasts. Our results demonstrated that OPG expression in chondrocyte increases bone mass in the proximal metaphysis of tibiae through negative regulation of osteoclast formation.
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Affiliation(s)
- Baoli Wang
- Key Lab of Hormone and Development (Ministry of Health), Metabolic Diseases Hospital and Tianjin Institute of Endocrinology, Tianjin Medical University, Tianjin 300070, China.,Department of Orthopaedics, Center for Musculoskeletal Research, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Hongting Jin
- Department of Orthopaedics, Center for Musculoskeletal Research, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Bing Shu
- Department of Orthopaedics, Center for Musculoskeletal Research, University of Rochester School of Medicine, Rochester, NY 14642, USA
| | - Ranim R Mira
- Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA
| | - Di Chen
- Department of Orthopaedics, Center for Musculoskeletal Research, University of Rochester School of Medicine, Rochester, NY 14642, USA.,Department of Biochemistry, Rush University Medical Center, Chicago, IL 60612, USA
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6
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Guo F, Feng J, Wang F, Li W, Gao Q, Chen Z, Shoff L, Donly KJ, Gluhak-Heinrich J, Chun YHP, Harris SE, MacDougall M, Chen S. Bmp2 deletion causes an amelogenesis imperfecta phenotype via regulating enamel gene expression. J Cell Physiol 2015; 230:1871-82. [PMID: 25545831 DOI: 10.1002/jcp.24915] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 12/09/2014] [Accepted: 12/18/2014] [Indexed: 01/16/2023]
Abstract
Although Bmp2 is essential for tooth formation, the role of Bmp2 during enamel formation remains unknown in vivo. In this study, the role of Bmp2 in regulation of enamel formation was investigated by the Bmp2 conditional knock out (Bmp2 cKO) mice. Teeth of Bmp2 cKO mice displayed severe and profound phenotypes with asymmetric and misshaped incisors as well as abrasion of incisors and molars. Scanning electron microscopy analysis showed that the enamel layer was hypoplastic and enamel lacked a typical prismatic pattern. Teeth from null mice were much more brittle as tested by shear and compressive moduli. Expression of enamel matrix protein genes, amelogenin, enamelin, and enamel-processing proteases, Mmp-20 and Klk4 was reduced in the Bmp2 cKO teeth as reflected in a reduced enamel formation. Exogenous Bmp2 up-regulated those gene expressions in mouse enamel organ epithelial cells. This result for the first time indicates Bmp2 signaling is essential for proper enamel development and mineralization in vivo.
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Affiliation(s)
- Feng Guo
- Department of Stomatology, Xiangya Hospital, Central South University, Changsha, China; Department of Developmental Dentistry, The University of Texas Health Science Center at San Antonio, Floyd Curl Drive, San Antonio, Texas
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7
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Blaney Davidson EN, van de Loo FAJ, van den Berg WB, van der Kraan PM. How to build an inducible cartilage-specific transgenic mouse. Arthritis Res Ther 2015; 16:210. [PMID: 25166474 PMCID: PMC4060449 DOI: 10.1186/ar4573] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 05/28/2014] [Indexed: 12/28/2022] Open
Abstract
Transgenic mice are used to study the roles of specific proteins in an intact living system. Use of transgenic mice to study processes in cartilage, however, poses some challenges. First of all, many factors involved in cartilage homeostasis and disease are also crucial factors in embryogenesis. Therefore, meddling with these factors often leads to death before birth, and mice who do survive cannot be considered normal. The build-up of cartilage in these mice is altered, making it nearly impossible to truly interpret the role of a protein in adult cartilage function.An elegant way to overcome these limitations is to make transgenic mice time- and tissue-specific, there by omitting side-effects in tissues other than cartilage and during embryology. This review discusses the potential building blocks for making an inducible cartilage-specific transgenic mouse. We review which promoters can be used to gain chondrocyte-specificity - all chondrocytes or a specific subset thereof - as well as different systems that can be used to enable inducibility of a transgene.
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8
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Yoshida CA, Kawane T, Moriishi T, Purushothaman A, Miyazaki T, Komori H, Mori M, Qin X, Hashimoto A, Sugahara K, Yamana K, Takada K, Komori T. Overexpression of Galnt3 in chondrocytes resulted in dwarfism due to the increase of mucin-type O-glycans and reduction of glycosaminoglycans. J Biol Chem 2014; 289:26584-26596. [PMID: 25107907 PMCID: PMC4176229 DOI: 10.1074/jbc.m114.555987] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 08/04/2014] [Indexed: 11/06/2022] Open
Abstract
Galnt3, UDP-N-acetyl-α-D-galactosamine:polypeptide N-acetylgalactosaminyltransferase 3, transfers N-acetyl-D-galactosamine to serine and threonine residues, initiating mucin type O-glycosylation of proteins. We searched the target genes of Runx2, which is an essential transcription factor for chondrocyte maturation, in chondrocytes and found that Galnt3 expression was up-regulated by Runx2 and severely reduced in Runx2(-/-) cartilaginous skeletons. To investigate the function of Galnt3 in chondrocytes, we generated Galnt3(-/-) mice and chondrocyte-specific Galnt3 transgenic mice under the control of the Col2a1 promoter-enhancer. Galnt3(-/-) mice showed a delay in endochondral ossification and shortened limbs at embryonic day 16.5, suggesting that Galnt3 is involved in chondrocyte maturation. Galnt3 transgenic mice presented dwarfism, the chondrocyte maturation was retarded, the cell cycle in chondrocytes was accelerated, premature chondrocyte apoptosis occurred, and the growth plates were disorganized. The binding of Vicia villosa agglutinin, which recognizes the Tn antigen (GalNAc-O-Ser/Thr), was drastically increased in chondrocytes, and aggrecan (Acan) was highly enriched with Tn antigen. However, safranin O staining, which recognizes glycosaminoglycans (GAGs), and Acan were severely reduced. Chondroitin sulfate was reduced in amount, but the elongation of chondroitin sulfate chains had not been severely disturbed in the isolated GAGs. These findings indicate that overexpression of Galnt3 in chondrocytes caused dwarfism due to the increase of mucin-type O-glycans and the reduction of GAGs, probably through competition with xylosyltransferases, which initiate GAG chains by attaching O-linked xylose to serine residues, suggesting a negative effect of Galnt family proteins on Acan deposition in addition to the positive effect of Galnt3 on chondrocyte maturation.
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Affiliation(s)
- Carolina Andrea Yoshida
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Tetsuya Kawane
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Takeshi Moriishi
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Anurag Purushothaman
- Department of Biochemistry, Kobe Pharmaceutical University, Kobe 658-0003, Japan
| | - Toshihiro Miyazaki
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Hisato Komori
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Masako Mori
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Xin Qin
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan
| | - Ayako Hashimoto
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan,; Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuyuki Sugahara
- Department of Biochemistry, Kobe Pharmaceutical University, Kobe 658-0003, Japan,; Proteoglycan Signaling and Therapeutics Research Group, Faculty of Advanced Life Science, Hokkaido University Graduate School of Life Science, Frontier Research Center for Post-Genomic Science and Technology, Sapporo 001-0021, Japan, and
| | - Kei Yamana
- Teijin Institute for Biomedical Research, Teijin Ltd., Hino, Tokyo 191-8512, Japan
| | - Kenji Takada
- Department of Orthodontics and Dentofacial Orthopedics, Graduate School of Dentistry, Osaka University, Suita, Osaka 565-0871, Japan
| | - Toshihisa Komori
- Department of Cell Biology, Unit of Basic Medical Sciences, Nagasaki University Graduate School of Biomedical Sciences, 1-7-1 Sakamoto, Nagasaki 852-8588, Japan,.
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9
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Wang Y, Wang J, Bai D, Song J, Ye R, Zhao Z, Lei L, Hao J, Jiang C, Fang S, An S, Cheng Q, Li J. Cell proliferation is promoted by compressive stress during early stage of chondrogenic differentiation of rat BMSCs. J Cell Physiol 2013; 228:1935-42. [DOI: 10.1002/jcp.24359] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2012] [Accepted: 03/11/2013] [Indexed: 12/25/2022]
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10
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Jash A, Yun K, Sahoo A, So JS, Im SH. Looping mediated interaction between the promoter and 3' UTR regulates type II collagen expression in chondrocytes. PLoS One 2012; 7:e40828. [PMID: 22815835 PMCID: PMC3397959 DOI: 10.1371/journal.pone.0040828] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Accepted: 06/13/2012] [Indexed: 11/18/2022] Open
Abstract
Type II collagen is the major component of articular cartilage and is mainly synthesized by chondrocytes. Repeated sub-culturing of primary chondrocytes leads to reduction of type II collagen gene (Col2a1) expression, which mimics the process of chondrocyte dedifferentiation. Although the functional importance of Col2a1 expression has been extensively investigated, mechanism of transcriptional regulation during chondrocyte dedifferentiation is still unclear. In this study, we have investigated the crosstalk between cis-acting DNA element and transcription factor on Col2a1 expression in primary chondrocytes. Bioinformatic analysis revealed the potential regulatory regions in the Col2a1 genomic locus. Among them, promoter and 3′ untranslated region (UTR) showed highly accessible chromatin architecture with enriched recruitment of active chromatin markers in primary chondrocytes. 3′ UTR has a potent enhancer function which recruits Lef1 (Lymphoid enhancer binding factor 1) transcription factor, leading to juxtaposition of the 3′ UTR with the promoter through gene looping resulting in up-regulation of Col2a1 gene transcription. Knock-down of endogenous Lef1 level significantly reduced the gene looping and subsequently down-regulated Col2a1 expression. However, these regulatory loci become inaccessible due to condensed chromatin architecture as chondrocytes dedifferentiate which was accompanied by a reduction of gene looping and down-regulation of Col2a1 expression. Our results indicate that Lef1 mediated looping between promoter and 3′ UTR under the permissive chromatin architecture upregulates Col2a1 expression in primary chondrocytes.
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Affiliation(s)
- Arijita Jash
- School of Life Sciences and Immune Synapse Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Kangsun Yun
- School of Life Sciences and Immune Synapse Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Anupama Sahoo
- School of Life Sciences and Immune Synapse Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Jae-Seon So
- School of Life Sciences and Immune Synapse Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
| | - Sin-Hyeog Im
- School of Life Sciences and Immune Synapse Research Center, Gwangju Institute of Science and Technology (GIST), Gwangju, Korea
- * E-mail:
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11
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Sox9/Sox6 and Sp1 are involved in the insulin-like growth factor-I-mediated upregulation of human type II collagen gene expression in articular chondrocytes. J Mol Med (Berl) 2012; 90:649-66. [DOI: 10.1007/s00109-011-0842-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 11/20/2011] [Accepted: 11/22/2011] [Indexed: 11/29/2022]
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12
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Akiyama H, Lefebvre V. Unraveling the transcriptional regulatory machinery in chondrogenesis. J Bone Miner Metab 2011; 29:390-5. [PMID: 21594584 PMCID: PMC3354916 DOI: 10.1007/s00774-011-0273-9] [Citation(s) in RCA: 131] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2011] [Accepted: 04/06/2011] [Indexed: 12/19/2022]
Abstract
Since the discovery of SOX9 mutations in the severe human skeletal malformation syndrome campomelic dysplasia in 1994, Sox9 was shown to be both required and sufficient for chondrocyte specification and differentiation. At the same time, its distant relatives Sox5 and Sox6 were shown to act in redundancy with each other to robustly enhance its functions. The Sox trio is currently best known for its ability to activate the genes for cartilage-specific extracellular matrix components. Sox9 and Sox5/6 homodimerize through domains adjacent to their Sry-related high-mobility-group DNA-binding domain to increase the efficiency of their cooperative binding to chondrocyte-specific enhancers. Sox9 possesses a potent transactivation domain and thereby recruits diverse transcriptional co-activators, histone-modifying enzymes, subunits of the mediator complex, and components of the general transcriptional machinery, such as CBP/p300, Med12, Med25, and Wwp2. This information helps us begin to unravel the mechanisms responsible for Sox9-mediated transcription. We review here the discovery of this master chondrogenic trio and its roles in chondrogenesis in vivo and at the molecular level, and we discuss how these pioneering studies open the way for many additional studies that are needed to further increase our understanding of the transcriptional regulatory machinery operating in chondrogenesis.
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Affiliation(s)
- Haruhiko Akiyama
- Department of Orthopaedics, Kyoto University, 54 Kawahara-cho, Shogoin, Sakyo, Kyoto 606-8507, Japan.
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13
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Abstract
Osteoarthritis (OA), the most prevalent aging-related joint disease, is characterized by insufficient extracellular matrix synthesis and articular cartilage degradation, mediated by several proteinases, including Adamts-5. miR-140 is one of a very limited number of noncoding microRNAs (miRNAs) specifically expressed in cartilage; however, its role in development and/or tissue maintenance is largely uncharacterized. To examine miR-140 function in tissue development and homeostasis, we generated a mouse line through a targeted deletion of miR-140. miR-140(-/-) mice manifested a mild skeletal phenotype with a short stature, although the structure of the articular joint cartilage appeared grossly normal in 1-mo-old miR-140(-/-) mice. Interestingly, miR-140(-/-) mice showed age-related OA-like changes characterized by proteoglycan loss and fibrillation of articular cartilage. Conversely, transgenic (TG) mice overexpressing miR-140 in cartilage were resistant to antigen-induced arthritis. OA-like changes in miR-140-deficient mice can be attributed, in part, to elevated Adamts-5 expression, regulated directly by miR-140. We show that miR-140 regulates cartilage development and homeostasis, and its loss contributes to the development of age-related OA-like changes.
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14
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Sox9 directly promotes Bapx1 gene expression to repress Runx2 in chondrocytes. Exp Cell Res 2009; 315:2231-40. [PMID: 19306868 DOI: 10.1016/j.yexcr.2009.03.008] [Citation(s) in RCA: 106] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 03/13/2009] [Accepted: 03/14/2009] [Indexed: 12/31/2022]
Abstract
The transcription factor, Sry-related High Mobility Group (HMG) box containing gene 9 (Sox9), plays a critical role in cartilage development by initiating chondrogenesis and preventing the subsequent maturation process called chondrocyte hypertrophy. This suppression mechanism by Sox9 on late-stage chondrogenesis partially results from the inhibition of Runt-related transcription factor 2 (Runx2), the main activator of hypertrophic chondrocyte differentiation. However, the precise mechanism by which Sox9 regulates late chondrogenesis is poorly understood. In the present study, the transcriptional repressor vertebrate homolog of Drosophila bagpipe (Bapx1) was found to be a direct target of Sox9 for repression of Runx2 expression in chondrocytes. We identified a critical Sox9 responsive region in the Bapx1 promoter via a luciferase reporter assay. Analysis by chromatin immunoprecipitation and electrophoretic mobility shift assays indicated that Sox9 physically bound to this region of the Bapx1 promoter. Consistent with the notion that Bapx1 and Sox9 act as negative regulators of chondrocyte hypertrophy by regulating Runx2 expression, transient knockdown of Sox9 or Bapx1 expression by shRNA in chondrocytes increased Runx2 expression, as well as expression of the late chondrogenesis marker, Col10a1. Furthermore, while over-expression of Sox9 decreased Runx2 and Col10a1 expressions, simultaneous transient knockdown of Bapx1 diminished that Sox9 over-expressing effect. Our findings reveal that the molecular pathway modulated by Bapx1 links two major regulators in chondrogenesis, Sox9 and Runx2, to coordinate skeletal formation.
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15
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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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Chen M, Zhu M, Awad H, Li TF, Sheu TJ, Boyce BF, Chen D, O'Keefe RJ. Inhibition of beta-catenin signaling causes defects in postnatal cartilage development. J Cell Sci 2008; 121:1455-65. [PMID: 18397998 DOI: 10.1242/jcs.020362] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Wnt/beta-catenin signaling pathway is essential for normal skeletal development because conditional gain or loss of function of beta-catenin in cartilage results in embryonic or early postnatal death. To address the role of beta-catenin in postnatal skeletal growth and development, Col2a1-ICAT transgenic mice were generated. Mice were viable and had normal size at birth, but became progressively runted. Transgene expression was limited to the chondrocytes in the growth plate and articular cartilages and was associated with decreased beta-catenin signaling. Col2a1-ICAT transgenic mice showed reduced chondrocyte proliferation and differentiation, and an increase in chondrocyte apoptosis, leading to decreased widths of the proliferating and hypertrophic zones, delayed formation of the secondary ossification center, and reduced skeletal growth. Isolated primary Col2a1-ICAT transgenic chondrocytes showed reduced expression of chondrocyte genes associated with maturation, and demonstrated that VEGF gene expression requires cooperative interactions between BMP2 and beta-catenin signaling. Altogether the findings confirm a crucial role for Wnt/beta-catenin in postnatal growth.
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Affiliation(s)
- Mo Chen
- Department of Orthopaedics, Center for Musculoskeletal Research, University of Rochester School of Medicine, Rochester, NY 14642, USA
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17
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Rockel JS, Kudirka JC, Guzi AJ, Bernier SM. Regulation of Sox9 activity by crosstalk with nuclear factor-kappaB and retinoic acid receptors. Arthritis Res Ther 2008; 10:R3. [PMID: 18182117 PMCID: PMC2374456 DOI: 10.1186/ar2349] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2007] [Revised: 11/08/2007] [Accepted: 01/09/2008] [Indexed: 11/19/2022] Open
Abstract
Introduction Sox9 and p300 cooperate to induce expression of cartilage-specific matrix proteins, including type II collagen, aggrecan and link protein. Tumour necrosis factor (TNF)-α, found in arthritic joints, activates nuclear factor-κB (NF-κB), whereas retinoic acid receptors (RARs) are activated by retinoid agonists, including all-trans retinoic acid (atRA). Like Sox9, the activity of NF-κB and RARs depends upon their association with p300. Separately, both TNF-α and atRA suppress cartilage matrix gene expression. We investigated how TNF-α and atRA alter the expression of cartilage matrix genes. Methods Primary cultures of rat chondrocytes were treated with TNF-α and/or atRA for 24 hours. Levels of transcripts encoding cartilage matrix proteins were determined by Northern blot analyses and quantitative real-time PCR. Nuclear protein levels, DNA binding and functional activity of transcription factors were assessed by immunoblotting, electrophoretic mobility shift assays and reporter assays, respectively. Results Together, TNF-α and atRA diminished transcript levels of cartilage matrix proteins and Sox9 activity more than each factor alone. However, neither agent altered nuclear levels of Sox9, and TNF-α did not affect protein binding to the Col2a1 48-base-pair minimal enhancer sequence. The effect of TNF-α, but not that of atRA, on Sox9 activity was dependent on NF-κB activation. Furthermore, atRA reduced NF-κB activity and DNA binding. To address the role of p300, we over-expressed constitutively active mitogen-activated protein kinase kinase kinase (caMEKK)1 to increase p300 acetylase activity. caMEKK1 enhanced basal NF-κB activity and atRA-induced RAR activity. Over-expression of caMEKK1 also enhanced basal Sox9 activity and suppressed the inhibitory effects of TNF-α and atRA on Sox9 function. In addition, over-expression of p300 restored Sox9 activity suppressed by TNF-α and atRA to normal levels. Conclusion NF-κB and RARs converge to reduce Sox9 activity and cartilage matrix gene expression, probably by limiting the availability of p300. This process may be critical for the loss of cartilage matrix synthesis in inflammatory joint diseases. Therefore, agents that increase p300 levels or activity in chondrocytes may be useful therapeutically.
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Affiliation(s)
- Jason S Rockel
- Canadian Institutes of Health Research Group in Skeletal Development and Remodeling, Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, Canada.
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18
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Loots GG. Genomic identification of regulatory elements by evolutionary sequence comparison and functional analysis. ADVANCES IN GENETICS 2008; 61:269-93. [PMID: 18282510 DOI: 10.1016/s0065-2660(07)00010-7] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Despite remarkable recent advances in genomics that have enabled us to identify most of the genes in the human genome, comparable efforts to define transcriptional cis-regulatory elements that control gene expression are lagging behind. The difficulty of this task stems from two equally important problems: our knowledge of how regulatory elements are encoded in genomes remains elementary, and there is a vast genomic search space for regulatory elements, since most of mammalian genomes are noncoding. Comparative genomic approaches are having a remarkable impact on the study of transcriptional regulation in eukaryotes and currently represent the most efficient and reliable methods of predicting noncoding sequences likely to control the patterns of gene expression. By subjecting eukaryotic genomic sequences to computational comparisons and subsequent experimentation, we are inching our way toward a more comprehensive catalog of common regulatory motifs that lie behind fundamental biological processes. We are still far from comprehending how the transcriptional regulatory code is encrypted in the human genome and providing an initial global view of regulatory gene networks, but collectively, the continued development of comparative and experimental approaches will rapidly expand our knowledge of the transcriptional regulome.
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Affiliation(s)
- Gabriela G Loots
- Biosciences and Biotechnology Division, Chemistry, Materials and Life Sciences Directorate, Lawrence Livermore National Laboratory, Livermore, California 94550, USA
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Nakamura T, de Vega S, Fukumoto S, Jimenez L, Unda F, Yamada Y. Transcription factor epiprofin is essential for tooth morphogenesis by regulating epithelial cell fate and tooth number. J Biol Chem 2007; 283:4825-33. [PMID: 18156176 DOI: 10.1074/jbc.m708388200] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
In tooth morphogenesis, the dental epithelium and mesenchyme interact reciprocally for growth and differentiation to form the proper number and shapes of teeth. We previously identified epiprofin (Epfn), a gene preferentially expressed in dental epithelia, differentiated ameloblasts, and certain ectodermal organs. To identify the role of Epfn in tooth development, we created Epfn-deficient mice (Epfn-/-). Epfn-/- mice developed an excess number of teeth, enamel deficiency, defects in cusp and root formation, and abnormal dentin structure. Mutant tooth germs formed multiple dental epithelial buds into the mesenchyme. In Epfn-/- molars, rapid proliferation and differentiation of the inner dental epithelium were inhibited, and the dental epithelium retained the progenitor phenotype. Formation of the enamel knot, a signaling center for cusps, whose cells differentiate from the dental epithelium, was also inhibited. However, multiple premature nonproliferating enamel knot-like structures were formed ectopically. These dental epithelial abnormalities were accompanied by dysregulation of Lef-1, which is required for the normal transition from the bud to cap stage. Transfection of an Epfn vector promoted dental epithelial cell differentiation into ameloblasts and activated promoter activity of the enamel matrix ameloblastin gene. Our results suggest that in Epfn-deficient teeth, ectopic nonproliferating regions likely bud off from the self-renewable dental epithelium, form multiple branches, and eventually develop into supernumerary teeth. Thus, Epfn has multiple functions for cell fate determination of the dental epithelium by regulating both proliferation and differentiation, preventing continuous tooth budding and generation.
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Affiliation(s)
- Takashi Nakamura
- Laboratory of Cell and Developmental Biology, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892-4370, USA
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Ravindranath RMH, Devarajan A, Uchida T. Spatiotemporal expression of ameloblastin isoforms during murine tooth development. J Biol Chem 2007; 282:36370-6. [PMID: 17921454 DOI: 10.1074/jbc.m704731200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ameloblasts synthesize and secrete the enamel matrix proteins (amelogenin, ameloblastin, and enamelin). This investigation examined the profiles of ameloblastin in the ameloblasts and in the enamel matrix during different postnatal (PN) days (days 0-9) of development of mouse molar, using an antibody specific for C-terminal sequence of ameloblastin (Ct; GNKVHQPQVHNAWRF). Ameloblastin is found in three different molecular sizes (37, 55, and 66 kDa) in both ameloblasts and enamel matrix during PN development. In the ameloblasts, the sequence of expression of these fractions varied. The 37-kDa fraction was observed (even before the appearances of mRNA of the proteases, enamelysin and kallikrein-4) on days 0 and 1, persisted until day 3, and was not found thereafter. Other isoforms (55 and 66 kDa) distinctly appeared in ameloblasts after day 1, reached a peak on day 5, and remained thereafter. The Ct-positive granules appeared beaded in the ameloblasts on day 3. In the extracellular matrix, a 37-kDa (but not 66- or 55-kDa) fraction was detected on days 0 and 1 and remained in the matrix throughout the PN days. The larger isoforms (55 and 66 kDa) appeared in the enamel matrix from day 3 onward. On days 0-3, but not later, the 37-kDa isoform co-localizes with amelogenin in Tomes' process and formative enamel, as revealed by laser scan confocal microscopy. Autoradiography confirmed accumulation of 3H-labeled amelogenin trityrosyl motif peptide in the region of Tomes' process and formative enamel from day 0 to 3. These observations suggest that the 37-kDa isoform interacts with amelogenin during early tooth development.
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Affiliation(s)
- Rajeswari M H Ravindranath
- Center for Craniofacial Molecular Biology, School of Dentistry, University of Southern California Los Angeles, California 90033, USA.
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de Vega S, Iwamoto T, Nakamura T, Hozumi K, McKnight DA, Fisher LW, Fukumoto S, Yamada Y. TM14 is a new member of the fibulin family (fibulin-7) that interacts with extracellular matrix molecules and is active for cell binding. J Biol Chem 2007; 282:30878-88. [PMID: 17699513 DOI: 10.1074/jbc.m705847200] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
We identified a new extracellular protein, TM14, by differential hybridization using mouse tooth germ cDNA microarrays. TM14 cDNA encodes 440 amino acids containing a signal peptide. The protein contains 3 EGF modules at the center, a C-terminal domain homologous to the fibulin module, and a unique Sushi domain at the N terminus. In situ hybridization revealed that TM14 mRNA was expressed by preodontoblasts and odontoblasts in developing teeth. TM14 mRNA was also expressed in cartilage, hair follicles, and extraembryonic tissues of the placenta. Immunostaining revealed that TM14 was localized at the apical pericellular regions of preodontoblasts. When the dentin matrix was fully formed and dentin mineralization occurred, TM14 was present in the predentin matrix and along the dentinal tubules. We found that the recombinant TM14 protein was glycosylated with N-linked oligosaccharides and interacted with heparin, fibronectin, fibulin-1, and dentin sialophosphoprotein. We also found that TM14 preferentially bound dental mesenchyme cells and odontoblasts but not dental epithelial cells or nondental cells such as HeLa, COS7, or NIH3T3 cells. Heparin, EDTA, and anti-integrin beta1 antibody inhibited TM14 binding to dental mesenchyme cells, suggesting that both a heparan sulfate-containing cell surface receptor and an integrin are involved in TM14 cell binding. Our findings indicate that TM14 is a cell adhesion molecule that interacts with extracellular matrix molecules in teeth and suggest that TM14 plays important roles in both the differentiation and maintenance of odontoblasts as well as in dentin formation. Because of its protein characteristics, TM14 can be classified as a new member of the fibulin family: fibulin-7.
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Affiliation(s)
- Susana de Vega
- Laboratory of Cell and Developmental Biology, NIDCR, National Institutes of Health, Bethesda, Maryland 20892-4370, USA
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Ford-Hutchinson AF, Ali Z, Lines SE, Hallgrímsson B, Boyd SK, Jirik FR. Inactivation of Pten in osteo-chondroprogenitor cells leads to epiphyseal growth plate abnormalities and skeletal overgrowth. J Bone Miner Res 2007; 22:1245-59. [PMID: 17456009 DOI: 10.1359/jbmr.070420] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
UNLABELLED To study the role of the Pten tumor suppressor in skeletogenesis, we generated mice lacking this key phosphatidylinositol 3'-kinase pathway regulator in their osteo-chondroprogenitors. A phenotype of growth plate dysfunction and skeletal overgrowth was observed. INTRODUCTION Skeletogenesis is a complex process relying on a variety of ligands that activate a range of intracellular signal transduction pathways. Although many of these stimuli are known to activate phosphatidylinositol 3'-kinase (PI3K), the function of this pathway during cartilage development remains nebulous. To study the role of PI3K during skeletogenesis, we used mice deficient in a negative regulator of PI3K signaling, the tumor suppressor, Pten. MATERIALS AND METHODS Pten gene deletion in osteo-chondrodroprogenitors was obtained by interbreeding mice with loxP-flanked Pten exons with mice expressing the Cre recombinase under the control of the type II collagen gene promoter (Pten(flox/flox):Col2a1Cre mice). Phenotypic analyses included microcomputed tomography and immunohistochemistry techniques. RESULTS MicroCT revealed that Pten(flox/flox):Col2a1Cre mice exhibited both increased skeletal size, particularly of vertebrae, and massive trabeculation accompanied by increased cortical thickness. Primary spongiosa development and perichondrial bone collar formation were prominent in Pten(flox/flox):Col2a1Cre mice, and long bone growth plates were disorganized and showed both matrix overproduction and evidence of accelerated hypertrophic differentiation (indicated by an altered pattern of type X collagen and alkaline phosphatase expression). Consistent with increased PI3K signaling, Pten-deficient chondrocytes showed increased phospho-PKB/Akt and phospho-S6 immunostaining, reflective of increased mTOR and PDK1 activity. Interestingly, no significant change in growth plate proliferation was seen in Pten-deficient mice, and growth plate fusion was found at 6 months. CONCLUSIONS By virtue of its ability to modulate a key signal transduction pathway responsible for integrating multiple stimuli, Pten represents an important regulator of both skeletal size and bone architecture.
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Affiliation(s)
- Alice Fiona Ford-Hutchinson
- Department of Biochemistry and Molecular Biology, Alberta Bone and Joint Health Institute, University of Calgary, Calgary, Alberta, Canada
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Imai K, Dalal SS, Hambor J, Mitchell P, Okada Y, Horton WC, D'Armiento J. Bone growth retardation in mouse embryos expressing human collagenase 1. Am J Physiol Cell Physiol 2007; 293:C1209-15. [PMID: 17652426 DOI: 10.1152/ajpcell.00213.2007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cellular growth and differentiation are readouts of multiple signaling pathways from the intercellular and/or extracellular milieu. The extracellular matrix through the activation of cellular receptors transmits these signals. Therefore, extracellular matrix proteolysis could affect cell fate in a variety of biological events. However, the biological consequence of inadequate extracellular matrix degradation in vivo is not clear. We developed a mouse model expressing human collagenase (matrix metalloproteinase-1, MMP-1) under the control of Col2a1 promoter. The mice showed significant growth retardation during embryogenesis and a loss of the demarcation of zonal structure and columnar array of the cartilage. Immunological examination revealed increased degradation of type II collagen and upregulation of fibronectin and alpha(5)-integrin subunit in the transgenic cartilage. The resting zone and proliferating zone of the growth plate cartilage exhibited a simultaneous increase in bromodeoxyuridine (BrdU)-incorporated proliferating cells and terminal deoxynucleotidyl transferase-mediated X-dUTP nick-end labeling-positive apoptotic cells, respectively. Chondrocyte differentiation was not disturbed in the transgenic mice as evidenced by normal expression of the Ihh and type X collagen expression. These data demonstrate that type II collagen proteolysis is an important determinant for the skeletal outgrowth through modulation of chondrocyte survival and cartilagenous growth.
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MESH Headings
- Animals
- Animals, Newborn
- Apoptosis/genetics
- Apoptosis/physiology
- Blotting, Northern
- Blotting, Western
- Bone Development/genetics
- Bone Development/physiology
- Cartilage/abnormalities
- Cartilage/metabolism
- Chondrocytes/metabolism
- Chondrocytes/pathology
- Collagen Type II/genetics
- Collagen Type II/metabolism
- Embryo, Mammalian/abnormalities
- Embryo, Mammalian/metabolism
- Fetal Growth Retardation/genetics
- Fetal Growth Retardation/metabolism
- Fetal Growth Retardation/pathology
- Fibronectins/metabolism
- Gene Expression
- Growth Plate/abnormalities
- Growth Plate/metabolism
- Humans
- Integrin alpha5/metabolism
- Matrix Metalloproteinase 1/genetics
- Matrix Metalloproteinase 1/metabolism
- Mice
- Mice, Inbred Strains
- Mice, Transgenic
- Promoter Regions, Genetic/genetics
- Proto-Oncogene Proteins c-bcl-2/metabolism
- RNA, Messenger/genetics
- RNA, Messenger/metabolism
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Affiliation(s)
- Kazushi Imai
- Division of Molecular Medicine, Department of Medicine, College of Physicians and Surgeons of Columbia University, New York, NY, USA.
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Chen M, Lichtler AC, Sheu TJ, Xie C, Zhang X, O'Keefe RJ, Chen D. Generation of a transgenic mouse model with chondrocyte-specific and tamoxifen-inducible expression of Cre recombinase. Genesis 2007; 45:44-50. [PMID: 17211877 PMCID: PMC2654410 DOI: 10.1002/dvg.20261] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Postnatal cartilage development and growth are regulated by key growth factors and signaling molecules. To fully understand the function of these regulators, an inducible and chondrocyte-specific gene deletion system needs to be established to circumvent the perinatal lethality. In this report, we have generated a transgenic mouse model (Col2a1-CreER(T2)) in which expression of the Cre recombinase is driven by the chondrocyte-specific col2a1 promoter in a tamoxifen-inducible manner. To determine the specificity and efficiency of the Cre recombination, we have bred Col2a1-CreER(T2) mice with Rosa26R reporter mice. The X-Gal staining showed that the Cre recombination is specifically achieved in cartilage tissues with tamoxifen-induction. In vitro experiments of chondrocyte cell culture also demonstrate the 4-hydroxy tamoxifen-induced Cre recombination. These results demonstrate that Col2a1-CreER(T2) transgenic mice can be used as a valuable tool for an inducible and chondrocyte-specific gene deletion approach.
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Affiliation(s)
- Mo Chen
- Department of Orthopaedics, Center for Musculoskeletal Research, University of Rochester School of Medicine, Rochester, New York 14642, USA
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25
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Nakamura E, Nguyen MT, Mackem S. Kinetics of tamoxifen-regulated Cre activity in mice using a cartilage-specific CreERT to assay temporal activity windows along the proximodistal limb skeleton. Dev Dyn 2006; 235:2603-12. [PMID: 16894608 DOI: 10.1002/dvdy.20892] [Citation(s) in RCA: 200] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Cartilage differentiation occurs over a broad time range from early embryonic development, when the mesenchymal condensations that give rise to cartilage models for future bone first appear, and continuing through adult life, when there is ongoing maintenance of articular joint surfaces and re-activation of cartilage formation after fracture. The chondrogenic response also figures in the pathogenesis of degenerative and inflammatory joint diseases. We have generated a transgenic line expressing tamoxifen-dependent Cre recombinase that gives efficient recombination in the chondrogenic lineage, both during embryogenesis and postnatally, and provides a valuable tool for analysis of gene function selectively in chondrogenic cells using conditional genetic approaches. Because the cartilage model of the limb skeleton forms progressively in a proximodistal order during discrete, well-defined time periods, evaluation of the spatial extent of tamoxifen-induced recombination along the limb axis during these time windows has also enabled us to examine the pharmacokinetics of single-dose tamoxifen injections during pregnancy.
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Affiliation(s)
- Eiichiro Nakamura
- Laboratory of Pathology, Center for Cancer Research, NCI, NIH, Bethesda, Maryland 20892, USA
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Yang X, Li J, Qin H, Yang H, Li J, Zhou P, Liang Y, Han H. Mint Represses Transactivation of the Type II Collagen Gene Enhancer through Interaction with αA-crystallin-binding Protein 1. J Biol Chem 2005; 280:18710-6. [PMID: 15778499 DOI: 10.1074/jbc.m500859200] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Collagen type II is an extracellular matrix protein important for cartilage and bone formation, and its expression is controlled by multiple cis- and trans-acting elements, including the zinc finger transcription factor alpha A-crystallin-binding protein 1 (CRYBP1). Here we show that MSX2-interacting nuclear target protein (MINT), a conserved transcriptional repressor, associates with CRYBP1 and negatively regulates the transactivation of the collagen type II gene (Col2a1) enhancer. We identified CRYBP1 as a binding partner of MINT by screening a mouse embryonic cDNA library using the yeast two-hybrid system. We demonstrated that the C terminus of MINT interacts with the C terminus of CRYBP1 using the mammalian cell two-hybrid assay, glutathione S-transferase pull-down, and co-immunoprecipitation analyses. Furthermore, MINT and CRYBP1 form a complex on the Col2a1 enhancer, as shown by chromatin immunoprecipitation and gel shift assays. In the presence of CRYBP1, overexpression of MINT or its C-terminal fragment in cells repressed a reporter construct driven by the Col2a1 enhancer elements. This transcription repression is dependent on histone deacetylase, the main co-repressor recruited by MINT. The present study shows that MINT is involved in CRYBP1-mediated Col2a1 gene repression and may play a role in regulation of cartilage development.
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Affiliation(s)
- Xi Yang
- Department of Medical Genetics and Developmental Biology, State Key Laboratory of Cancer Biology, Fourth Military Medical University, Xian 710032, China
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Kutz WE, Gong Y, Warman ML. WISP3, the gene responsible for the human skeletal disease progressive pseudorheumatoid dysplasia, is not essential for skeletal function in mice. Mol Cell Biol 2005; 25:414-21. [PMID: 15601861 PMCID: PMC538768 DOI: 10.1128/mcb.25.1.414-421.2005] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In humans, loss-of-function mutations in WISP3 cause the autosomal recessive skeletal disease progressive pseudorheumatoid dysplasia (PPD) (Online Mendelian Inheritance in Man database number 208230). WISP3 encodes Wnt1-inducible signaling protein 3, a cysteine-rich, multidomain, secreted protein, whose paralogous CCN (connective tissue growth factor/cysteine-rich protein 61/nephroblastoma overexpressed) family members have been implicated in diverse biologic processes including skeletal, vascular, and neural development. To understand the role of WISP3 in the skeleton, we targeted the Wisp3 gene in mice by creating a mutant allele comparable to that which causes human disease. We also created transgenic mice that overexpress human WISP3 in cartilage. Surprisingly, homozygous Wisp3 mutant mice appear normal and do not recapitulate any of the morphological, radiographic, or histological abnormalities seen in patients with PPD. Mice that overexpress WISP3 are also normal. We conclude, that in contrast to humans, Wisp3 is not an essential participant during skeletal growth or homeostasis in mice.
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Affiliation(s)
- Wendy E Kutz
- Department of Genetics, Case Western Reserve University, 2109 Adelbert Road, BRB 719, Cleveland, OH 44106-4955, USA
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Klooster AR, Bernier SM. Tumor necrosis factor alpha and epidermal growth factor act additively to inhibit matrix gene expression by chondrocyte. Arthritis Res Ther 2004; 7:R127-38. [PMID: 15642133 PMCID: PMC1064891 DOI: 10.1186/ar1464] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2004] [Revised: 10/08/2004] [Accepted: 10/22/2004] [Indexed: 01/09/2023] Open
Abstract
The failure of chondrocytes to replace the lost extracellular matrix contributes to the progression of degenerative disorders of cartilage. Inflammatory mediators present in the joint regulate the breakdown of the established matrix and the synthesis of new extracellular matrix molecules. In the present study, we investigated the effects of tumor necrosis factor alpha (TNF-alpha) and epidermal growth factor (EGF) on chondrocyte morphology and matrix gene expression. Chondrocytes were isolated from distal femoral condyles of neonatal rats. Cells in primary culture displayed a cobblestone appearance. EGF, but not TNF-alpha, increased the number of cells exhibiting an elongated morphology. TNF-alpha potentiated the effect of EGF on chondrocyte morphology. Individually, TNF-alpha and EGF diminished levels of aggrecan and type II collagen mRNA. In combination, the effects of TNF-alpha and EGF were additive, indicating the involvement of discrete signaling pathways. Cell viability was not compromised by TNF-alpha or by EGF, alone or in combination. EGF alone did not activate NF-kappaB or alter NF-kappaB activation by TNF-alpha. Pharmacologic studies indicated that the effects of TNF-alpha and EGF alone or in combination were independent of protein kinase C signaling, but were dependent on MEK1/2 activity. Finally, we analyzed the involvement of Sox-9 using a reporter construct of the 48 base pair minimal enhancer of type II collagen. TNF-alpha attenuated enhancer activity as expected; in contrast, EGF did not alter either the effect of TNF-alpha or basal activity. TNF-alpha and EGF, acting through distinct signaling pathways, thus have additive adverse effects on chondrocyte function. These findings provide critical insights into the control of chondrocytes through the integration of multiple extracellular signals.
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Affiliation(s)
- Aaron R Klooster
- CIHR Group in Skeletal Development and Remodeling, Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada.
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Schneiderbauer MM, Dutton CM, Scully SP. Signaling “cross-talk” between TGF-β1 and ECM signals in chondrocytic cells. Cell Signal 2004; 16:1133-40. [PMID: 15240008 DOI: 10.1016/j.cellsig.2004.03.004] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2003] [Revised: 03/03/2004] [Accepted: 03/04/2004] [Indexed: 12/23/2022]
Abstract
The objective of this investigation was to clarify how the integrin pathway modulates downstream effectors of the TGF-beta1 pathway in chondrocytic cell signaling. The levels of Smad2 and Smad3 phosphorylation upon TGF-beta1 or alpha2beta1 integrin (Type II collagen) stimulation were analyzed by Western blotting techniques. Cellular response was determined by quantitation of procollagen gene expression. Stimulation of cells with TGF-beta1 and Type II collagen led to rapid phosphorylation of Smad2 and 3 with phosphorylation peaking between 15 min and 1 h. Combined stimulation led to a synergistic increase in the phosphorylation of Smad2 and Smad3. Type II collagen gene expression paralleled Smad phosphorylation. Type II collagen modulates the TGF signaling cascade involving Smad2 and Smad3 leading to an increase in Type II collagen transcription. Therefore, we conclude that TGF-beta1 and integrin stimuli interact prior to Smad2 and 3 phosphorylation in the cytoplasm of chondrocytic cells and regulates the expression of ECM components in chondrocytes.
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Abstract
Extracellular matrix metabolism plays a central role in development of skeletal tissues and in most orthopaedic diseases and trauma such as fracture or osteotomy repair, arthritis, cartilage repair, and congenital skeletal deformity. During development or disease, specific genes must be expressed in order to make or repair appropriate extracellular matrix. For example, specific gene expression patterns are characteristic of bone and cartilage. The precise expression pattern depends on a balance of positive and negative transcription factors, proteins that control the synthesis of mRNA from the specific gene. In cartilage, a number of studies indicate that Sox transcription factors are critical positive regulators in genes such as COL2A1, COL9A2, COL11A2, aggrecan, and CD-RAP. In addition, negative regulators are also essential to fine tune gene regulation in chondrocytes and to turn off gene expression in noncartilaginous tissues. Negative transcription factors in cartilage include partial differentialEF-1, snail/slug, CYRBP1, NT2, and C/EBP. Runx2 and osterix are critical transcription factors for osteogenesis but also have some influence on chondrogenesis. The availability of cis-regulatory sites in specific genes combined with the availability of transcription factors in the nucleus determines the level of gene expression.
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Affiliation(s)
- Ken Okazaki
- Department of Orthopaedic Surgery, Washington University School of Medicine at Barnes-Jewish Hospital, St. Louis, MO 63110, USA
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31
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Poustie MW, Carran J, McEleney K, Dixon SJ, Anastassiades TP, Bernier SM. N-Butyryl Glucosamine Increases Matrix Gene Expression by Chondrocytes. J Pharmacol Exp Ther 2004; 311:610-6. [PMID: 15240824 DOI: 10.1124/jpet.104.067769] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Proteoglycan synthesis is dependent on N-acetyl glucosamine (GlcNAc) produced by the hexosamine biosynthetic pathway or obtained exogenously. Although used therapeutically to relieve symptoms of osteoarthritis, the actions of glucosamine and its analogs on cartilage are poorly understood. The purpose of this study was to determine the effects on chondrocytes of N-acylated-glucosamine analogs bearing alkyl chains of different lengths. Chondrocytes isolated from neonatal rat femoral condyles were cultured in the presence of glucosamine analogs. GlcNAc, N-proprionyl glucosamine (GlcNPro), or N-butyryl glucosamine (GlcNBu) did not alter cell number, lactate dehydrogenase release, or metabolic acid production, consistent with lack of cytotoxicity. Treatment of chondrocyte cultures with GlcNBu for 6 days significantly increased levels of type II collagen and aggrecan mRNA as determined by Northern blot analysis. In contrast, GlcNAc and GlcNPro had no significant effect. A significant increase in type II collagen mRNA was induced by GlcNBu within 3 days. GlcNBu did not alter stability of type II collagen mRNA, suggesting it acts on gene transcription. We have previously shown that tumor necrosis factor-alpha (TNFalpha) decreases levels of type II collagen mRNA. However, chondrocytes pretreated with GlcNBu maintained type II collagen mRNA at control levels in the presence of TNFalpha. These results establish that the N-butyrylated analog of glucosamine but not GlcNAc promotes matrix gene expression by chondrocytes. Thus, GlcNBu has the potential for use as a chondro-protective agent in osteoarthritis.
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Affiliation(s)
- Mark W Poustie
- Canadian Institutes of Health Research Group in Skeletal Development and Remodeling, Department of Anatomy and Cell Biology, The University of Western Ontario, London, Ontario, Canada, N6A 5C1
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Hatakeyama Y, Tuan RS, Shum L. Distinct functions of BMP4 and GDF5 in the regulation of chondrogenesis. J Cell Biochem 2004; 91:1204-17. [PMID: 15048875 DOI: 10.1002/jcb.20019] [Citation(s) in RCA: 121] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Bone morphogenetic protein 4 (BMP4) and growth/differentiation factor 5 (GDF5) are closely related protein family members and regulate early cartilage patterning and differentiation. In this study, we compared the functional outcome of their actions systematically at various stages of chondrogenesis in mouse embryonic limb bud mesenchyme grown in micromass cultures. Overall, both growth factors enhanced cartilage growth and differentiation in these cultures. Uniquely, BMP4 not only accelerated the formation and maturation of cartilaginous nodules, but also induced internodular mesenchymal cells to express cartilage differentiation markers. On the other hand, GDF5 increased the number of prechondrogenic mesenchymal cell condensation and cartilaginous nodules, without altering the overall pattern of differentiation. In addition, GDF5 caused a more sustained elevated expression level of Sox9 relative to that associated with BMP4. BMP4 accelerated chondrocyte maturation throughout the cultures and sustained an elevated level of Col10 expression, whereas GDF5 caused a transient increase in Col10 expression. Taken together, we conclude that BMP4 is instructive to chondrogenesis and induces mesenchymal cells toward the chondrogenic lineage. Furthermore, BMP4 accelerates the progression of cartilage differentiation to maturation. GDF5 enhances cartilage formation by promoting chondroprogenitor cell aggregation, and amplifying the responses of cartilage differentiation markers. These differences may serve to fine-tune the normal cartilage differentiation program, and can be exploited for the molecular manipulation in biomimetics.
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Affiliation(s)
- Yuji Hatakeyama
- Cartilage Biology and Orthopaedics Branch, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland 20892-6402, USA
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33
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Seki K, Fujimori T, Savagner P, Hata A, Aikawa T, Ogata N, Nabeshima Y, Kaechoong L. Mouse Snail family transcription repressors regulate chondrocyte, extracellular matrix, type II collagen, and aggrecan. J Biol Chem 2003; 278:41862-70. [PMID: 12917416 PMCID: PMC2253659 DOI: 10.1074/jbc.m308336200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Snail family genes are conserved among species during evolution and encode transcription factors expressed at different stages of development in different tissues. These genes are involved in a broad spectrum of biological functions: cell differentiation, cell motility, cell cycle regulation, and apoptosis. However, little is known about the target genes involved in these functions. Here we show that mouse Snail family members, Snail (Sna) and Slug (Slugh), are involved in chondrocyte differentiation by controlling the expression of type II collagen (Col2a1) and aggrecan. In situ hybridization analysis of developing mouse limb demonstrated that Snail and Slug mRNAs were highly expressed in hypertrophic chondrocytes. Inversely, the expression of collagen type II mRNA disappeared during hypertrophic differentiation. Snail and Slug mRNA expression was down-regulated during differentiation of the mouse chondrogenic cell line ATDC5 and overexpression of exogenous Snail or Slug in ATDC5 cells inhibited expression of collagen type II and aggrecan mRNA. Reporter analysis revealed Snail and Slug suppressed the promoter activity of Col2a1, and the E-boxes in the promoter region were the responsible element. Gel shift assay demonstrated the binding of Snail to the E-box. Because type II collagen and aggrecan are major functional components of extracellular matrix in cartilage, these results suggest an important role for Snail-related transcription repressors during chondrocyte differentiation.
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Affiliation(s)
- Kenji Seki
- Endocrine Unit, Massachusetts General Hospital, Boston, MA 02114, USA.
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34
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Chadjichristos C, Ghayor C, Kypriotou M, Martin G, Renard E, Ala-Kokko L, Suske G, de Crombrugghe B, Pujol JP, Galéra P. Sp1 and Sp3 transcription factors mediate interleukin-1 beta down-regulation of human type II collagen gene expression in articular chondrocytes. J Biol Chem 2003; 278:39762-72. [PMID: 12888570 DOI: 10.1074/jbc.m303541200] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Interleukin-1 beta (IL-1 beta) is a pleiotropic cytokine that was shown to inhibit the biosynthesis of articular cartilage components. Here we demonstrate that IL-1 beta inhibits the production of newly synthesized collagens in proliferating rabbit articular chondrocytes and that this effect is accompanied by a decrease in the steady-state levels of type II collagen mRNA. IL-1 beta down-regulates COL2A1 gene transcription through a -41/-33 bp sequence that binds a multimeric complex including Sp1 and Sp3 transcription factors. Specificity of IL-1 beta effects on COL2A1 promoter activity was demonstrated in experiments in which transfection of a wild type -50/+1 sequence of COL2A1 promoter as a decoy oligonucleotide abolished the IL-1 beta inhibition of a -63/+47 COL2A1-mediated transcription. By contrast, transfection of the related oligonucleotide harboring a targeted mutation in the -41/-33 sequence did not modify the negative effect the cytokine. Because we demonstrated previously that Sp1 was a strong activator of COL2A1 gene expression via the -63/+1 promoter region, whereas Sp3 overexpression blocked Sp1-induced promoter activity and inhibited COL2A1 gene transcription, we conclude that IL-1 beta down-regulation of that gene, as we found previously for transforming growth factor-beta 1, is mediated by an increase in the Sp3/Sp1 ratio. Moreover, IL-1 beta increased steady-state levels of Sp1 and Sp3 mRNAs, whereas it enhanced Sp3 protein expression and inhibited Sp1 protein biosynthesis. Nevertheless, IL-1 beta decreased the binding activity of both Sp1 and Sp3 to the 63-bp short COL2A1 promoter, suggesting that the cytokine exerts a post-transcriptional regulatory mechanism on Sp1 and Sp3 gene expressions. Altogether, these data indicate that modulation of Sp3/Sp1 ratio in cartilage could be a potential target to prevent or limit the tissue degradation.
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Affiliation(s)
- Christos Chadjichristos
- Laboratoire de Biochimie du Tissu Conjonctif, Faculté de Médecine, CHU Niveau 3, Avenue de la Côte de Nacre, Caen Cedex 14032, France
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35
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Séguin CA, Bernier SM. TNFα suppresses link protein and type II collagen expression in chondrocytes: Role of MEK1/2 and NF-κB signaling pathways. J Cell Physiol 2003; 197:356-69. [PMID: 14566965 DOI: 10.1002/jcp.10371] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Tumor necrosis factor alpha (TNFalpha) inhibits matrix synthesis by chondrocytes in rheumatoid arthritis and osteoarthritis; however, the underlying signaling pathways are poorly characterized. This study investigated the TNFalpha-activated pathways regulating expression of two key components of the cartilage matrix-link protein and type II collagen. In rat articular chondrocytes, TNFalpha decreased link protein and type II collagen mRNA to undetectable levels within 48 h. Levels of link protein mRNA recovered more readily than type II collagen mRNA following removal of the cytokine. TNFalpha-mediated reduction in mRNA of both matrix molecules occurred at the level of transcription and, for link protein, mRNA stability. Turnover of type II collagen and link protein mRNA was dependent on new protein synthesis. In both prechondrocytes and articular chondrocytes, TNFalpha induced concentration-dependent activation of MEK1/2 and NF-kappaB, but not p38 or JNK. Sustained activation of NF-kappaB was observed for up to 72 h following continuous or transient exposure to TNFalpha. Using pharmacological and molecular approaches, the MEK1/2 and NF-kappaB pathways were found to mediate inhibition of type II collagen and link protein gene expression by TNFalpha. Both prechondrocytes and articular chondrocytes are targets of TNFalpha. This study identifies pathways through which TNFalpha perturbs the synthesis and organization of articular cartilage matrix during inflammation.
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Affiliation(s)
- Cheryle A Séguin
- CHIR Group in Skeletal Development and Remodeling, The University of Western Ontario, London, Ontario, Canada
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36
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Paine ML, Wang HJ, Luo W, Krebsbach PH, Snead ML. A transgenic animal model resembling amelogenesis imperfecta related to ameloblastin overexpression. J Biol Chem 2003; 278:19447-52. [PMID: 12657627 DOI: 10.1074/jbc.m300445200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Genetic diseases that affect tooth enamel are grouped under the classification amelogenesis imperfecta. Human pedigrees and experiments on transgenic and null mice have all demonstrated that mutations to the secreted proteins amelogenin, enamelin, and enamelysin result in visibly, structurally, or mechanically defective enamel. In an attempt to better define a physiologic function for ameloblastin during enamel formation, we have produced transgenic mice that misexpress the ameloblastin gene. These transgenic animals exhibit imperfections in their enamel that is evident at the nanoscale level. Specifically, ameloblastin overexpression influences enamel crystallite habit and enamel rod morphology. These findings suggest enamel crystallite habit and rod morphology are influenced by the temporal and spatial expression of ameloblastin and may implicate the role of the ameloblastin gene locus in the etiology of a number of undiagnosed autosomally dominant cases of amelogenesis imperfecta.
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Affiliation(s)
- Michael L Paine
- University of Southern California, School of Dentistry, Center for Craniofacial Molecular Biology, Los Angeles, California 90033, USA.
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37
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Yang Y, Topol L, Lee H, Wu J. Wnt5a and Wnt5b exhibit distinct activities in coordinating chondrocyte proliferation and differentiation. Development 2003; 130:1003-15. [PMID: 12538525 DOI: 10.1242/dev.00324] [Citation(s) in RCA: 298] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Proper longitudinal growth of long bones relies on the regulation of specific spatial patterns of chondrocyte proliferation and differentiation. We have studied the roles of two members of the Wnt family, Wnt5a and Wnt5b in long bone development. We show that Wnt5a is required for longitudinal skeletal outgrowth and that both Wnt5a and Wnt5b regulate the transition between different chondrocyte zones independently of the Indian hedgehog (Ihh)/parathyroid hormone-related peptide (PTHrP) negative feedback loop. We find that important cell cycle regulators such as cyclin D1 and p130, a member of the retinoblastoma family, exhibit complimentary expression patterns that correlate with the distinct proliferation and differentiation states of chondrocyte zones. Furthermore, we show that Wnt5a and Wnt5b appear to coordinate chondrocyte proliferation and differentiation by differentially regulating cyclin D1 and p130 expression, as well as chondrocyte-specific Col2a1 expression. Our data indicate that Wnt5a and Wnt5b control the pace of transitions between different chondrocyte zones.
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Affiliation(s)
- Yingzi Yang
- Genetic Disease Research Branch, National Human Genome Research Institute, National Institute of Health, Bethesda, MD 20892, USA.
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38
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Kypriotou M, Fossard-Demoor M, Chadjichristos C, Ghayor C, de Crombrugghe B, Pujol JP, Galéra P. SOX9 exerts a bifunctional effect on type II collagen gene (COL2A1) expression in chondrocytes depending on the differentiation state. DNA Cell Biol 2003; 22:119-29. [PMID: 12713737 DOI: 10.1089/104454903321515922] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
As a key transcription factor in cartilage formation, SOX9 is a potent activator of type II collagen expression, a phenotypic marker of articular chondrocytes. This study was designed to determine the potential role of SOX9 on COL2A1 gene transcription during chondrocyte dedifferentiation, a characteristic feature of osteoarthritic cartilage that can be partially mimicked in vitro by subculturing primary chondrocytes. Constructs containing different regions from the promoter and the first intron of human COL2A1 gene were transfected in differentiated (primary) and dedifferentiated (passaged) rabbit articular chondrocytes (RAC), together with an expression vector containing or not the SOX9 cDNA. As expected, low levels of SOX9 overexpression were capable of enhancing COL2A1 gene transcription in both fully differentiated and slightly phenotypically altered chondrocytes, through the specific intronic enhancer. In contrast, when overexpressed at high levels, SOX9 induced an inhibition of COL2A1 gene expression, mediated by the -266 bp promoter region, whatever the differentiation state of chondrocytes. However, in the advanced stages of dedifferentiation, SOX9, independently of its expression level, depressed COL2A1 transcriptional activity through the -63 bp short promoter. Although SOX9 has a crucial role in chondrocyte differentiation, our findings indicate that this factor cannot restore the phenotype of osteoarthritic chondrocytes by itself.
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Affiliation(s)
- Magdalini Kypriotou
- Laboratoire de Biochimie du Tissu Conjonctif, Faculté de Médecine, Caen Cedex, France
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39
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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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40
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Caterina JJ, Skobe Z, Shi J, Ding Y, Simmer JP, Birkedal-Hansen H, Bartlett JD. Enamelysin (matrix metalloproteinase 20)-deficient mice display an amelogenesis imperfecta phenotype. J Biol Chem 2002; 277:49598-604. [PMID: 12393861 DOI: 10.1074/jbc.m209100200] [Citation(s) in RCA: 191] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Enamelysin is a tooth-specific matrix metalloproteinase that is expressed during the early through middle stages of enamel development. The enamel matrix proteins amelogenin, ameloblastin, and enamelin are also expressed during this same approximate developmental time period, suggesting that enamelysin may play a role in their hydrolysis. In support of this interpretation, recombinant enamelysin was previously demonstrated to cleave recombinant amelogenin at virtually all of the precise sites known to occur in vivo. Thus, enamelysin is likely an important amelogenin-processing enzyme. To characterize the in vivo biological role of enamelysin during tooth development, we generated an enamelysin-deficient mouse by gene targeting. Although mice heterozygous for the mutation have no apparent phenotype, the enamelysin null mouse has a severe and profound tooth phenotype. Specifically, the null mouse does not process amelogenin properly, possesses an altered enamel matrix and rod pattern, has hypoplastic enamel that delaminates from the dentin, and has a deteriorating enamel organ morphology as development progresses. Our findings demonstrate that enamelysin activity is essential for proper enamel development.
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Affiliation(s)
- John J Caterina
- Matrix Metalloproteinase Unit, NIDCR, National Institutes of Health, Bethesda, Maryland 20892, USA
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41
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Yasuda K, Hirayoshi K, Hirata H, Kubota H, Hosokawa N, Nagata K. The Kruppel-like factor Zf9 and proteins in the Sp1 family regulate the expression of HSP47, a collagen-specific molecular chaperone. J Biol Chem 2002; 277:44613-22. [PMID: 12235161 DOI: 10.1074/jbc.m208558200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In several cells and tissues the synthesis of HSP47, a collagen-specific molecular chaperone in the endoplasmic reticulum, is closely correlated with the synthesis of collagen. We previously reported that the Sp1 binding site at -210 bp in the promoter region and the first and second introns are required for the tissue-specific expression of HSP47 in transgenic mice (Hirata, H., Yamamura, I., Yasuda, K., Kobayashi, A., Tada, N., Suzuki, M., Hirayoshi, K., Hosokawa, N., and Nagata, K. (1999) J. Biol. Chem. 274, 35703-35710). Here, we analyze how these introns influence the transcriptional regulation of the hsp47 gene in BALB/c 3T3 cells, which produce high levels of HSP47. In vitro promoter analysis using a luciferase reporter and gel mobility shift analysis revealed that two cis-acting elements in the first and second introns, BS5-B and EP7-D, respectively, are required for the activation of hsp47 in BALB/c 3T3 cells. Several members of the Kruppel-like factor (KLF) family of proteins were identified as BS5-B-binding proteins by yeast one-hybrid analysis using these elements as baits. One of these proteins, KLF-6/Zf9, binds to the BS5-B element and activates expression of the reporter construct when transfected into cells. Chromatin immunoprecipitation assay analysis revealed that the endogenous KLF-6/Zf9 binds the BS5-B elements that contain the CACCC motif, which is a consensus recognition sequence for other proteins in the KLF family. We also showed that BS5-B and EP7-D are bound by two members of the Sp1 family, Sp2 and Sp3. These results suggest that at least three sequences are required for the constitutive expression of hsp47 in BALB/c 3T3 cells: the -210 bp Sp1 binding site, the BS5-B element in the first intron, and the EP7-D element in the second intron. We suggest that KLF proteins regulate the transcription of hsp47 by binding the BS5-B element in cooperation with Sp2 and/or Sp3.
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Affiliation(s)
- Kunihiko Yasuda
- Department of Molecular and Cellular Biology, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto 606-8397, Japan
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42
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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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43
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Abstract
Ameloblastin is a tooth-specific extracellular matrix protein that is thought to play a role in enamel crystal formation in the developing dentition. The murine ameloblastin promoter functions in a cell type-specific manner and contains cis-acting elements that function both to enhance and to suppress transcription. The objective of this study was to determine whether the transcription factor Cbfa1, known to be essential for transcription of other mineralized tissue genes, is also required for ameloblastin transcription. Site-directed mutagenesis of the Cbfa1-binding site (-248 base pairs) termed osteoblast-specific element 2 (OSE2) decreased ameloblastin promoter activity by greater than 50% in ameloblast-like cells. No differences in promoter activity were observed in two other oral tissue-derived cell lines transfected with similar constructs. Nuclear factor binding to the ameloblastin promoter was also shown to be cell type-specific and was altered by site-specific mutations in the OSE2 site. Cbfa1 was specifically shown to participate in the DNA-protein complexes between nuclear factors and the ameloblastin OSE2 site by supershift electrophoretic mobility shift assays. The findings that Cbfa1 interacts with functionally important regions of the ameloblastin promoter while promoter activity is diminished in constructs containing site-directed mutations in the Cbfa1 site indicate that Cbfa1 possesses an important function in transcription of the ameloblastin gene.
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Affiliation(s)
- S Dhamija
- University of Michigan School of Dentistry, Department of Oral Medicine, Pathology, and Oncology, Ann Arbor, Michigan 48109-1078, USA
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44
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Wang D, Canaff L, Davidson D, Corluka A, Liu H, Hendy GN, Henderson JE. Alterations in the sensing and transport of phosphate and calcium by differentiating chondrocytes. J Biol Chem 2001; 276:33995-4005. [PMID: 11404353 DOI: 10.1074/jbc.m007757200] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
During endochondral bone formation and fracture healing, cells committed to chondrogenesis undergo a temporally restricted program of differentiation that is characterized by sequential changes in their phenotype and gene expression. This results in the manufacture, remodeling, and mineralization of a cartilage template on which bone is laid down. Articular chondrocytes undergo a similar but restricted differentiation program that does not proceed to mineralization, except in pathologic conditions such as osteoarthritis. The pathogenesis of disorders of cartilage development and metabolism, including osteochondrodysplasia, fracture non-union, and osteoarthritis remain poorly defined. We used the CFK2 model to examine the potential roles of phosphate and calcium ions in the regulatory pathways that mediate chondrogenesis and cartilage maturation. Differentiation was monitored over a 4-week period using a combination of morphological, biochemical, and molecular markers that have been characterized in vivo and in vitro. CFK2 cells expressed the type III sodium-dependent phosphate transporters Glvr-1 and Ram-1, as well as a calcium-sensing mechanism. Regulated expression and activity of Glvr-1 by extracellular phosphate and parathyroid hormone-related protein was restricted to an early stage of CFK2 differentiation, as evidenced by expression of type II collagen, proteoglycan, and Ihh. On the other hand, regulated expression and activity of a calcium-sensing receptor by extracellular calcium was most evident after 2 weeks of differentiation, concomitant with an increase in type X collagen expression, alkaline phosphatase activity and parathyroid hormone/parathyroid hormone-related protein receptor expression. On the basis of these temporally restricted changes in the sensing and transport of phosphate and calcium, we predict that extracellular phosphate plays a role in the commitment of chondrogenic cells to differentiation, whereas extracellular calcium plays a role at a later stage in their differentiation program.
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Affiliation(s)
- D Wang
- Department of Medicine, McGill University, Lady Davis Institute for Medical Research, Sir Mortimer B. Davis-Jewish General Hospital Montréal, Québec, Canada H3T 1E2
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45
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Deten A, Hölzl A, Leicht M, Barth W, Zimmer HG. Changes in extracellular matrix and in transforming growth factor beta isoforms after coronary artery ligation in rats. J Mol Cell Cardiol 2001; 33:1191-207. [PMID: 11444923 DOI: 10.1006/jmcc.2001.1383] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Extensive myocardial remodeling occurs after transmural myocardial infarction (MI). The infarcted myocardium is being replaced by scar tissue after gradual resorption of the necrotic tissue. The remodeling process involves both synthesis and degradation of collagens as major components of the extracellular matrix (ECM). In the present study we have analyzed the time-dependent changes of the processes related to this fibrosis in the infarct area and in the non-infarcted left ventricle (LV) six hours to 82 days after occlusion of the left anterior descending coronary artery (LAD) in rats. We also examined whether changes occurred in the expression pattern of the transforming growth factor (TGF) beta isoforms, since this cytokine is known as powerful inductor of fibrosis. Elevation in colligin expression preceded the pronounced increase in mRNA expression of both type I and type III collagen after MI from day three onwards. The maximal increase in colligin protein in the infarct area coincided with the most pronounced expression of collagen I and collagen III mRNA expression. Also, the expression and activity of matrix metalloproteinases (MMPs) and of tissue inhibitor of matrix metalloproteinase (TIMP)-2 mRNA were increased predominantly in the infarct area. TGF beta(1)and TGF-beta(2)expression increased within the first days after MI, whereas TGF-beta(3)expression was elevated predominantly in the infarct area. This pronounced increase in TGF-beta(3)persisted up to 82 days and correlated positively with the parameters of ECM metabolism. Thus, the scar formation is an ongoing dynamic process in which TGF-beta(3)seems to play an active role in the complex ventricular remodeling.
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Affiliation(s)
- A Deten
- Carl-Ludwig-Institute of Physiology, University of Leipzig, Germany.
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46
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Ueta C, Iwamoto M, Kanatani N, Yoshida C, Liu Y, Enomoto-Iwamoto M, Ohmori T, Enomoto H, Nakata K, Takada K, Kurisu K, Komori T. Skeletal malformations caused by overexpression of Cbfa1 or its dominant negative form in chondrocytes. J Cell Biol 2001; 153:87-100. [PMID: 11285276 PMCID: PMC2185519 DOI: 10.1083/jcb.153.1.87] [Citation(s) in RCA: 309] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
During skeletogenesis, cartilage develops to either permanent cartilage that persists through life or transient cartilage that is eventually replaced by bone. However, the mechanism by which cartilage phenotype is specified remains unclarified. Core binding factor alpha1 (Cbfa1) is an essential transcription factor for osteoblast differentiation and bone formation and has the ability to stimulate chondrocyte maturation in vitro. To understand the roles of Cbfa1 in chondrocytes during skeletal development, we generated transgenic mice that overexpress Cbfa1 or a dominant negative (DN)-Cbfa1 in chondrocytes under the control of a type II collagen promoter/enhancer. Both types of transgenic mice displayed dwarfism and skeletal malformations, which, however, resulted from opposite cellular phenotypes. Cbfa1 overexpression caused acceleration of endochondral ossification due to precocious chondrocyte maturation, whereas overexpression of DN-Cbfa1 suppressed maturation and delayed endochondral ossification. In addition, Cbfa1 transgenic mice failed to form most of their joints and permanent cartilage entered the endochondral pathway, whereas most chondrocytes in DN-Cbfa1 transgenic mice retained a marker for permanent cartilage. These data show that temporally and spatially regulated expression of Cbfa1 in chondrocytes is required for skeletogenesis, including formation of joints, permanent cartilages, and endochondral bones.
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Affiliation(s)
- Chisato Ueta
- Department of Molecular Medicine, Osaka University Medical School, Suita, Osaka 565-0871, Japan
| | - Masahiro Iwamoto
- Department of Oral Anatomy and Developmental Biology, Osaka University Faculty of Dentistry, Suita, Osaka 565-0871, Japan
| | - Naoko Kanatani
- Department of Molecular Medicine, Osaka University Medical School, Suita, Osaka 565-0871, Japan
| | - Carolina Yoshida
- Department of Molecular Medicine, Osaka University Medical School, Suita, Osaka 565-0871, Japan
- Department of Orthodontics and Dentofacial Orthopedics, Osaka University Faculty of Dentistry, Suita, Osaka 565-0871, Japan
| | - Yang Liu
- Department of Molecular Medicine, Osaka University Medical School, Suita, Osaka 565-0871, Japan
| | - Motomi Enomoto-Iwamoto
- Department of Biochemistry, Osaka University Faculty of Dentistry, Suita, Osaka 565-0871, Japan
| | - Tomoharu Ohmori
- Department of Oral Anatomy and Developmental Biology, Osaka University Faculty of Dentistry, Suita, Osaka 565-0871, Japan
| | - Hirayuki Enomoto
- Department of Molecular Medicine, Osaka University Medical School, Suita, Osaka 565-0871, Japan
| | - Ken Nakata
- Orthopedic Sports Medicine, Kansai Rosai Hospital, Amagasaki, Hyogo 660-8511, Japan
| | - Kenji Takada
- Department of Orthodontics and Dentofacial Orthopedics, Osaka University Faculty of Dentistry, Suita, Osaka 565-0871, Japan
| | - Kojiro Kurisu
- Department of Oral Anatomy and Developmental Biology, Osaka University Faculty of Dentistry, Suita, Osaka 565-0871, Japan
| | - Toshihisa Komori
- Department of Molecular Medicine, Osaka University Medical School, Suita, Osaka 565-0871, Japan
- Form and Function, Precursory Research for Embryonic Science and Technology, Japan Science and Technology Corporation, Suita, Osaka 565-0871, Japan
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Ghayor C, Herrouin JF, Chadjichristos C, Ala-Kokko L, Takigawa M, Pujol JP, Galéra P. Regulation of Human COL2A1 Gene Expression in Chondrocytes. J Biol Chem 2000. [DOI: 10.1016/s0021-9258(19)61527-9] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Paine CT, Paine ML, Luo W, Okamoto CT, Lyngstadaas SP, Snead ML. A tuftelin-interacting protein (TIP39) localizes to the apical secretory pole of mouse ameloblasts. J Biol Chem 2000; 275:22284-92. [PMID: 10806191 DOI: 10.1074/jbc.m000118200] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Enamel biomineralization is a complex process that involves interactions between extracellular matrix proteins. To identify proteins interacting with tuftelin, a potential nucleator of enamel crystallites, the yeast two-hybrid system was applied to a mouse tooth expression library and a tuftelin-interacting protein (TIP) was isolated for further characterization. Polyclonal antibodies were prepared against two recombinant variants of this protein. Both antibodies identified a major protein product in tooth organs at 39 kDa, and this protein has been called TIP39. Northern analysis showed TIP39 messenger RNA in multiple organs, a pattern similar to that of tuftelin messenger RNA. In situ hybridization of mandibles of 1-day-old mice detected TIP39 RNA in secretory ameloblasts and odontoblasts. Immunolocalization of TIP39 and tuftelin in cultured ameloblast-like cells showed that these two proteins colocalize. Within the developing tooth organ, TIP39 and tuftelin immunolocalized to the apical pole of secretory ameloblasts (Tomes' processes) and to the newly secreted extracellular enamel matrix. TIP39 amino acid sequence appears to be highly conserved with similarities to proteins in species as diverse as yeast and primates. Available sequence data and the findings reported here suggest a role for TIP39 in the secretory pathway of extracellular proteins.
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Affiliation(s)
- C T Paine
- Center for Craniofacial Molecular Biology, University of Southern California School of Dentistry, Los Angeles, California 90033-1004, USA.
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Tanaka K, Matsumoto Y, Nakatani F, Iwamoto Y, Yamada Y. A zinc finger transcription factor, alphaA-crystallin binding protein 1, is a negative regulator of the chondrocyte-specific enhancer of the alpha1(II) collagen gene. Mol Cell Biol 2000; 20:4428-35. [PMID: 10825206 PMCID: PMC85810 DOI: 10.1128/mcb.20.12.4428-4435.2000] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Transcription of the type II collagen gene (Col2a1) is regulated by multiple cis-acting sites. The enhancer element, which is located in the first intron, is necessary for high-level and cartilage-specific expression of Col2a1. A mouse limb bud cDNA expression library was screened by the Saccharomyces cerevisiae one-hybrid screening method to identify protein factors bound to the enhancer. A zinc finger protein, alphaA-crystallin binding protein 1 (CRYBP1), which had been reported to bind to the mouse alphaA-crystallin gene promoter, was isolated. We herein demonstrate that CRYBP1 is involved in the negative regulation of Col2a1 enhancer activity. CRYBP1 mRNA expression was downregulated during chondrocyte differentiation in vitro. In situ hybridization analysis of developing mouse cartilage showed that CRYBP1 mRNA was also downregulated during mesenchymal condensation and that CRYBP1 mRNA was highly expressed by hypertrophic chondrocytes, but at very low levels by resting and proliferating chondrocytes. Expression of recombinant CRYBP1 in a transfected rat chondrosarcoma cell line inhibited Col2a1 enhancer activity. Electrophoretic mobility shift assays showed that CRYBP1 bound a specific sequence within the Col2a1 enhancer and inhibited the binding of Sox9, an activator for Col2a1, to the enhancer. Cotransfection of CRYBP1 with Sox9 into BALB/c 3T3 cells inhibited activation of the Col2a1 enhancer by Sox9. These results suggest a novel mechanism that negatively regulates cartilage-specific expression of Col2a1.
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Affiliation(s)
- K Tanaka
- Craniofacial Developmental Biology and Regeneration Branch, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, Maryland 20892, USA
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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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