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Chen Y, Tang B, Jiang W, Sun M, Zhang H, Tao Y, Wang H, Xiang D, Bai H, Guo M, Zhao P, Yan W, Huang X, Chen T, Lian C, Zhang J. miR-486-5p Attenuates Steroid-Induced Adipogenesis and Osteonecrosis of the Femoral Head Via TBX2/P21 Axis. Stem Cells 2023; 41:711-723. [PMID: 37210668 DOI: 10.1093/stmcls/sxad038] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 05/10/2023] [Indexed: 05/22/2023]
Abstract
Enhanced adipogenic differentiation of mesenchymal stem cells (MSCs) is considered as a major risk factor for steroid-induced osteonecrosis of the femoral head (SOFNH). The role of microRNAs during this process has sparked interest. miR-486-5p expression was down-regulated significantly in femoral head bone tissues of both SONFH patients and rat models. The purpose of this study was to reveal the role of miR-486-5p on MSCs adipogenesis and SONFH progression. The present study showed that miR-486-5p could significantly inhibit adipogenesis of 3T3-L1 cells by suppressing mitotic clonal expansion (MCE). And upregulated expression of P21, which was caused by miR-486-5p mediated TBX2 decrease, was responsible for inhibited MCE. Further, miR-486-5p was demonstrated to effectively inhibit steroid-induced fat formation in the femoral head and prevented SONFH progression in a rat model. Considering the potent effects of miR-486-5p on attenuating adipogenesis, it seems to be a promising target for the treatment of SONFH.
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Affiliation(s)
- Yu Chen
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Boyu Tang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Weiqian Jiang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Mingjie Sun
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Hongrui Zhang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Yuzhang Tao
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Hongwei Wang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Dulei Xiang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Haobo Bai
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Mingkang Guo
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Pei Zhao
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Wenlong Yan
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Xiao Huang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Tingmei Chen
- Key Laboratory of Clinical Laboratory Diagnostics (Ministry of Education), College of Laboratory Medicine, Chongqing Medical University, Chongqing, People's Republic of China
| | - Chengjie Lian
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
| | - Jian Zhang
- Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People's Republic of China
- Orthopedic Laboratory of Chongqing Medical University, Chongqing, People's Republic of China
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Rafeeq MM, Murad HAS, Najumuddin, Ullah S, Ahmed Z, Alam Q, Bilal M, Habib AH, Sain ZM, Khan MJ, Umair M. Case report: A novel de novo loss of function variant in the DNA-binding domain of TBX2 causes severe osteochondrodysplasia. Front Genet 2023; 13:1117500. [PMID: 36733940 PMCID: PMC9888409 DOI: 10.3389/fgene.2022.1117500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 12/29/2022] [Indexed: 01/19/2023] Open
Abstract
Background: T-box family members are transcription factors characterized by highly conserved residues corresponding to the DNA-binding domain known as the T-box. TBX2 has been implicated in several developmental processes, such as coordinating cell fate, patterning, and morphogenesis of a wide range of tissues and organs, including lungs, limbs, heart, kidneys, craniofacial structures, and mammary glands. Methods: In the present study, we have clinically and genetically characterized a proband showing a severe form of chondrodysplasia with developmental delay. Whole-exome sequencing (WES), Sanger sequencing, and 3D protein modeling were performed in the present investigation. Results: Whole-exome sequencing revealed a novel nonsense variant (c.529A>T; p.Lys177*; NM_005994.4) in TBX2. 3D-TBX2 protein modeling revealed a substantial reduction of the mutated protein, which might lead to a loss of function (LOF) or nonsense-mediated decay (NMD). Conclusion: This study has not only expanded the mutation spectrum in the gene TBX2 but also facilitated the diagnosis and genetic counseling of related features in affected families.
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Affiliation(s)
- Misbahuddin M. Rafeeq
- Department of Pharmacology, Faculty of Medicine, Rabigh, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Hussam Aly Sayed Murad
- Department of Pharmacology, Faculty of Medicine, Rabigh, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Najumuddin
- National Center for Bioinformatics (NCB), Quaid-i-Azam University, Islamabad, Pakistan
| | - Samee Ullah
- National Center for Bioinformatics (NCB), Islamabad, Pakistan
| | - Zaheer Ahmed
- Department of Biosciences, COMSATS University, Islamabad, Pakistan
| | - Qamre Alam
- Molecular Genomics and Precision Medicine, ExpressMed Laboratories, Zinj, Bahrain
| | - Muhammad Bilal
- Department of Biochemistry, Quaid-i-Azam University, Islamabad, Pakistan
| | - Alaa Hamed Habib
- Department of Physiology, Faculty of Medicine, King Abdulaziz University, Jeddah, Saudi Arabia
| | - Ziaullah M. Sain
- Department of Microbiology, Faculty of Medicine, Rabigh, King Abdulaziz University, Jeddah, Saudi Arabia
| | | | - Muhammad Umair
- Department of Life Sciences, School of Science, University of Management and Technology (UMT), Lahore, Pakistan,Medical Genomics Research Department, King Abdullah International Medical Research Center (KAIMRC), King Saud Bin Abdulaziz University for Health Sciences, Ministry of National Guard Health Affairs (MNGH), Riyadh, Saudi Arabia,*Correspondence: Muhammad Umair, ,
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Woloszyk A, Tuong ZK, Perez L, Aguilar L, Bankole AI, Evans CH, Glatt V. Fracture hematoma micro-architecture influences transcriptional profile and plays a crucial role in determining bone healing outcomes. BIOMATERIALS ADVANCES 2022; 139:213027. [PMID: 35882120 DOI: 10.1016/j.bioadv.2022.213027] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/27/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
The hematoma that forms between broken fragments of bone serves as a natural fibrin scaffold, and its removal from the defect site delays bone healing. The hypothesis of this study is that the microarchitectural and mechanical properties of the initially formed hematoma has a significant effect on the regulation of the biological process, which ultimately determines the outcome of bone healing. To mimic three healing conditions in the rat femur (normal, delayed, and non-healing bone defects), three different defect sizes of 0.5, 1.5, and 5.0 mm, are respectively used. The analysis of 3-day-old hematomas demonstrates clear differences in fibrin clot micro-architecture in terms of fiber diameter, fiber density, and porosity of the formed fibrin network, which result in different mechanical properties (stiffness) of the hematoma in each model. Those differences directly affect the biological processes involved. Specifically, RNA-sequencing reveals almost 700 differentially expressed genes between normally healing and non-healing defects, including significantly up-regulated essential osteogenic genes in normally healing defects, also differences in immune cell populations, activated osteogenic transcriptional regulators as well as potential novel marker genes. Most importantly, this study demonstrates that the healing outcome has already been determined during the hematoma phase of bone healing, three days post-surgery.
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Affiliation(s)
- Anna Woloszyk
- Department of Orthopaedics, University of Texas Health Science Center, San Antonio 78229, TX, USA.
| | - Zewen K Tuong
- The University of Queensland Diamantina Institute, Faculty of Medicine, The University of Queensland, Woolloongabba 4102, QLD, Australia; Molecular Immunity Unit, Department of Medicine, University of Cambridge, Cambridge CB2 0AW, UK; Wellcome Trust Sanger Institute, Hinxton, Cambridge CB10 1SA, UK.
| | - Louis Perez
- Department of Orthopaedics, University of Texas Health Science Center, San Antonio 78229, TX, USA.
| | - Leonardo Aguilar
- Department of Orthopaedics, University of Texas Health Science Center, San Antonio 78229, TX, USA.
| | - Abraham I Bankole
- Department of Orthopaedics, University of Texas Health Science Center, San Antonio 78229, TX, USA.
| | - Christopher H Evans
- Rehabilitation Medicine Research Center, Mayo Clinic, Rochester 55902, MN, USA.
| | - Vaida Glatt
- Department of Orthopaedics, University of Texas Health Science Center, San Antonio 78229, TX, USA.
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Mäkitie RE, Toiviainen-Salo S, Kaitila I, Mäkitie O. A Novel Osteochondrodysplasia With Empty Sella Associates With a TBX2 Variant. Front Endocrinol (Lausanne) 2022; 13:845889. [PMID: 35311234 PMCID: PMC8927981 DOI: 10.3389/fendo.2022.845889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Accepted: 02/09/2022] [Indexed: 11/13/2022] Open
Abstract
Skeletal dysplasias comprise a heterogenous group of developmental disorders of skeletal and cartilaginous tissues. Several different forms have been described and the full spectrum of their clinical manifestations and underlying genetic causes are still incompletely understood. We report a three-generation Finnish family with an unusual, autosomal dominant form of osteochondrodysplasia and an empty sella. Affected individuals (age range 24-44 years) exhibit unusual codfish-shaped vertebrae, severe early-onset and debilitating osteoarthritis and an empty sella without endocrine abnormalities. Clinical characteristics also include mild dysmorphic features, reduced sitting height ratio, and obesity. Whole-exome sequencing excluded known skeletal dysplasias and identified a novel heterozygous missense mutation c.899C>T (p.Thr300Met) in TBX2, confirmed by Sanger sequencing. TBX2 is important for development of the skeleton and the brain and three prior reports have described variations in TBX2 in patients portraying a complex phenotype with vertebral anomalies, craniofacial dysmorphism and endocrine dysfunctions. Our mutation lies near a previously reported disease-causing variant and is predicted pathogenic with deleterious effects on protein function. Our findings expand the current spectrum of skeletal dysplasias, support the association of TBX2 mutations with skeletal dysplasia and suggest a role for TBX2 in development of the spinal and craniofacial structures and the pituitary gland.
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Affiliation(s)
- Riikka E. Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Department of Otorhinolaryngology–Head and Neck Surgery, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
- *Correspondence: Riikka E. Mäkitie,
| | - Sanna Toiviainen-Salo
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Medical Imaging Center, Pediatric Radiology, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
| | - Ilkka Kaitila
- Department of Medical Genetics, University of Helsinki, Helsinki, Finland
- Department of Clinical Genetics, Helsinki University Hospital, Helsinki, Finland
| | - Outi Mäkitie
- Folkhälsan Institute of Genetics, Helsinki, Finland
- Research Program for Clinical and Molecular Metabolism, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Children’s Hospital, Pediatric Research Center, University of Helsinki and Helsinki University Hospital, Helsinki, Finland
- Department of Molecular Medicine and Surgery and Center for Molecular Medicine, Karolinska Institutet, Stockholm, Sweden
- Department of Clinical Genetics, Karolinska University Hospital, Stockholm, Sweden
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Reinhardt S, Schuck F, Stoye N, Hartmann T, Grimm MOW, Pflugfelder G, Endres K. Transcriptional repression of the ectodomain sheddase ADAM10 by TBX2 and potential implication for Alzheimer's disease. Cell Mol Life Sci 2019; 76:1005-1025. [PMID: 30599067 PMCID: PMC11105458 DOI: 10.1007/s00018-018-2998-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2018] [Revised: 12/11/2018] [Accepted: 12/12/2018] [Indexed: 12/15/2022]
Abstract
BACKGROUND The ADAM10-mediated cleavage of transmembrane proteins regulates cellular processes such as proliferation or migration. Substrate cleavage by ADAM10 has also been implicated in pathological situations such as cancer or Morbus Alzheimer. Therefore, identifying endogenous molecules, which modulate the amount and consequently the activity of ADAM10, might contribute to a deeper understanding of the enzyme's role in both, physiology and pathology. METHOD To elucidate the underlying cellular mechanism of the TBX2-mediated repression of ADAM10 gene expression, we performed overexpression, RNAi-mediated knockdown and pharmacological inhibition studies in the human neuroblastoma cell line SH-SY5Y. Expression analysis was conducted by e.g. real-time RT-PCR or western blot techniques. To identify the binding region of TBX2 within the ADAM10 promoter, we used luciferase reporter assay on deletion constructs and EMSA/WEMSA experiments. In addition, we analyzed a TBX2 loss-of-function Drosophila model regarding the expression of ADAM10 orthologs by qPCR. Furthermore, we quantified the mRNA level of TBX2 in post-mortem brain tissue of AD patients. RESULTS Here, we report TBX2 as a transcriptional repressor of ADAM10 gene expression: both, the DNA-binding domain and the repression domain of TBX2 were necessary to effect transcriptional repression of ADAM10 in neuronal SH-SY5Y cells. This regulatory mechanism required HDAC1 as a co-factor of TBX2. Transcriptional repression was mediated by two functional TBX2 binding sites within the core promoter sequence (- 315 to - 286 bp). Analysis of a TBX2 loss-of-function Drosophila model revealed that kuzbanian and kuzbanian-like, orthologs of ADAM10, were derepressed compared to wild type. Vice versa, analysis of cortical brain samples of AD-patients, which showed reduced ADAM10 mRNA levels, revealed a 2.5-fold elevation of TBX2, while TBX3 and TBX21 levels were not affected. CONCLUSION Our results characterize TBX2 as a repressor of ADAM10 gene expression and suggest that this regulatory interaction is conserved across tissues and species.
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Affiliation(s)
- Sven Reinhardt
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, Untere Zahlbacher Strasse 8, 55131, Mainz, Germany
| | - Florian Schuck
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, Untere Zahlbacher Strasse 8, 55131, Mainz, Germany
| | - Nicolai Stoye
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, Untere Zahlbacher Strasse 8, 55131, Mainz, Germany
| | - Tobias Hartmann
- Deutsches Institut für Demenz Prävention (DIDP), Neurodegeneration and Neurobiology, Saarland University, Kirrbergerstrasse 1, 66421, Homburg, Saar, Germany
- Experimental Neurology, Saarland University, Kirrbergerstrasse 1, 66421, Homburg, Saar, Germany
| | - Marcus O W Grimm
- Deutsches Institut für Demenz Prävention (DIDP), Neurodegeneration and Neurobiology, Saarland University, Kirrbergerstrasse 1, 66421, Homburg, Saar, Germany
- Experimental Neurology, Saarland University, Kirrbergerstrasse 1, 66421, Homburg, Saar, Germany
| | - Gert Pflugfelder
- Institute of Developmental Biology and Neurobiology, Johannes Gutenberg University, Becherweg 32, 55128, Mainz, Germany
| | - Kristina Endres
- Department of Psychiatry and Psychotherapy, University Medical Center of the Johannes Gutenberg University Mainz, Untere Zahlbacher Strasse 8, 55131, Mainz, Germany.
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Liu X, Miao Z, Wang Z, Zhao T, Xu Y, Song Y, Huang J, Zhang J, Xu H, Wu J, Xu H. TBX2 overexpression promotes proliferation and invasion through epithelial-mesenchymal transition and ERK signaling pathway. Exp Ther Med 2018; 17:723-729. [PMID: 30651856 PMCID: PMC6307397 DOI: 10.3892/etm.2018.7028] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 06/13/2018] [Indexed: 12/16/2022] Open
Abstract
The present study aimed to clarify the clinical significance and biological effects of T-box (TBX)2 and its potential mechanism in gastric cancer (GC). TBX2 protein expression levels in human GC tissues were investigated using immunohistochemistry, and it was demonstrated that TBX2 was overexpressed in 55.9% (90/161) GC samples. TBX2 overexpression correlated with tumor invasion, advanced tumor node metastasis stage and presence of lymph node metastasis. In addition, TBX2 correlated with poor patient survival. To investigate the effect of TBX2 on biological behaviors, TBX2 plasmid transfection was performed in SGC-7901 cells and TBX2 small interfering RNA knockdown was carried out in BGC-823 cells. MTT and matrigel invasion assays demonstrated that TBX2 overexpression promoted proliferation and invasion, whereas TBX2 depletion inhibited proliferation and invasion. TBX2 overexpression also promoted epithelial-mesenchymal transition by downregulating E-cadherin and upregulating N-cadherin. TBX2 overexpression also upregulated matrix metalloproteinase (MMP)2, MMP9, cyclin E and phosphorylated-extracellular signal regulated kinase levels, however downregulated p21. In conclusion, TBX2 may serve as an effective predictor and therapeutic target in human GC.
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Affiliation(s)
- Xingyu Liu
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Zhifeng Miao
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Zhenning Wang
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Tingting Zhao
- Department of Breast Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yingying Xu
- Department of Breast Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Yongxi Song
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Jinyu Huang
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Junyan Zhang
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Hao Xu
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Jianhua Wu
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
| | - Huimian Xu
- Department of Surgical Oncology, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning 110001, P.R. China
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Lv Y, Si M, Chen N, Li Y, Ma X, Yang H, Zhang L, Zhu H, Xu GY, Wu GP, Cao C. TBX2 over-expression promotes nasopharyngeal cancer cell proliferation and invasion. Oncotarget 2017; 8:52699-52707. [PMID: 28881763 PMCID: PMC5581062 DOI: 10.18632/oncotarget.17084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 03/12/2017] [Indexed: 12/31/2022] Open
Abstract
TBX2 is a member of the T box transcription factor family. Its expression and potential biological functions in nasopharyngeal cancer (NPC) cells are studied here. We showed that TBX2 mRNA and protein expression was significantly elevated in multiple human NPC tissues, as compared with that in adjacent normal tissues. Knockdown of TBX2 by targeted-siRNA significantly inhibited proliferation and invasion of NPC cells (CNE-1 and HONE-1 lines). Meanwhile, TBX2 knockdown also induced G1-phase cell cycle arrest. At the molecular level, we discovered that expressions of several tumor suppressor genes, including p21, p27, phosphatase with tensin homology (PTEN) and E-Cadherin, were increased dramatically after TBX2 knockdown in above NPC cells. Collectively, our results imply that TBX2 over-expression promotes NPC cell proliferation and invasion, possibly via silencing several key tumor suppressor genes.
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Affiliation(s)
- Yan Lv
- Center of Translational Medicine, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China
| | - Meng Si
- Department of Neurology, The Second Affiliated Hospital of Soochow University, Suzhou, China
| | - Nannan Chen
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Ya Li
- Institute of Neuroscience, Soochow University, Suzhou, China
| | - Xingkai Ma
- Department of Otolaryngology, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China
| | - Huijun Yang
- Department of Otolaryngology, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China
| | - Ling Zhang
- Center of Translational Medicine, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China
| | - Hongyan Zhu
- Center of Translational Medicine, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China
| | - Guang-Yin Xu
- Center of Translational Medicine, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China.,Institute of Neuroscience, Soochow University, Suzhou, China
| | - Ge-Ping Wu
- Center of Translational Medicine, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China.,Department of Otolaryngology, The First People Hospital of Zhangjiagang City, Soochow University, Suzhou, China
| | - C Cao
- Institute of Neuroscience, Soochow University, Suzhou, China
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8
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Baptissart M, Vega A, Martinot E, Pommier AJ, Houten SM, Marceau G, de Haze A, Baron S, Schoonjans K, Lobaccaro JMA, Volle DH. Bile acids alter male fertility through G-protein-coupled bile acid receptor 1 signaling pathways in mice. Hepatology 2014; 60:1054-65. [PMID: 24798773 DOI: 10.1002/hep.27204] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 05/01/2014] [Indexed: 12/12/2022]
Abstract
UNLABELLED Bile acids (BAs) are signaling molecules that are involved in many physiological functions, such as glucose and energy metabolism. These effects are mediated through activation of the nuclear and membrane receptors, farnesoid X receptor (FXR-α) and TGR5 (G-protein-coupled bile acid receptor 1; GPBAR1). Although both receptors are expressed within the testes, the potential effect of BAs on testis physiology and male fertility has not been explored thus far. Here, we demonstrate that mice fed a diet supplemented with cholic acid have reduced fertility subsequent to testicular defects. Initially, germ cell sloughing and rupture of the blood-testis barrier occur and are correlated with decreased protein accumulation of connexin-43 (Cx43) and N-cadherin, whereas at later stages, apoptosis of spermatids is observed. These abnormalities are associated with increased intratesticular BA levels in general and deoxycholic acid, a TGR5 agonist, in particular. We demonstrate here that Tgr5 is expressed within the germ cell lineage, where it represses Cx43 expression through regulation of the transcriptional repressor, T-box transcription factor 2 gene. Consistent with this finding, mice deficient for Tgr5 are protected against the deleterious testicular effects of BA exposure. CONCLUSIONS These data identify the testis as a new target of BAs and emphasize TGR5 as a critical element in testicular pathophysiology. This work may open new perspectives on the potential effect of BAs on testis physiology during liver dysfunction.
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Affiliation(s)
- Marine Baptissart
- INSERM U 1103, Génétique Reproduction et Développement (GReD), Aubière, France; Clermont Université, Université Blaise, Pascal, GReD, BP 80026, Aubière, France; CNRS, UMR 6293, GReD, Aubière, France; Centre de Recherche en Nutrition Humaine d'Auvergne, Clermont-Ferrand, France
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Thi Thu HN, Haw Tien SF, Loh SL, Bok Yan JS, Korzh V. Tbx2a is required for specification of endodermal pouches during development of the pharyngeal arches. PLoS One 2013; 8:e77171. [PMID: 24130849 PMCID: PMC3795029 DOI: 10.1371/journal.pone.0077171] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Accepted: 09/01/2013] [Indexed: 11/21/2022] Open
Abstract
Tbx2 is a member of the T-box family of transcription factors essential for embryo- and organogenesis. A deficiency in the zebrafish paralogue tbx2a causes abnormalities of the pharyngeal arches in a p53-independent manner. The pharyngeal arches are formed by derivatives of all three embryonic germ layers: endodermal pouches, mesenchymal condensations and neural crest cells. While tbx2a expression is restricted to the endodermal pouches, its function is required for the normal morphogenesis of the entire pharyngeal arches. Given the similar function of Tbx1 in craniofacial development, we explored the possibility of an interaction between Tbx1 and Tbx2a. The use of bimolecular fluorescence complementation revealed the interaction between Tbx2a and Tbx1, thus providing support for the idea that functional interaction between different, co-expressed Tbx proteins could be a common theme across developmental processes in cell lineages and tissues. Together, this work provides mechanistic insight into the role of TBX2 in human disorders affecting the face and neck.
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Affiliation(s)
- Hang Nguyen Thi Thu
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | | | - Siau Lin Loh
- Institute of Molecular and Cell Biology, Singapore, Singapore
| | - Jimmy So Bok Yan
- Department of Surgery, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
| | - Vladimir Korzh
- Institute of Molecular and Cell Biology, Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore, Singapore
- * E-mail:
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The transcription factors TBX2 and TBX3 interact with human papillomavirus 16 (HPV16) L2 and repress the long control region of HPVs. J Virol 2013; 87:4461-74. [PMID: 23388722 DOI: 10.1128/jvi.01803-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The minor capsid protein L2 of human papillomaviruses (HPVs) has multiple functions during the viral life cycle. Although L2 is required for effective invasion and morphogenesis, only a few cellular interaction partners are known so far. Using yeast two-hybrid screening, we identified the transcription factor TBX2 as a novel interaction partner of HPV type 16 (HPV16) L2. Coimmunoprecipitations and immunofluorescence analyses confirmed the L2-TBX2 interaction and revealed that L2 also interacts with TBX3, another member of the T-box family. Transcription of the early genes during HPV infection is under the control of an upstream enhancer and early promoter region, the long control region (LCR). In promoter-reporter gene assays, we observed that TBX2 and TBX3 repress transcription from the LCR and that this effect is enhanced by L2. Repression of the HPV LCR by TBX2/3 seems to be a conserved mechanism, as it was also observed with the LCRs of different HPV types. Finally, interaction of TBX2 with the LCR was detected by chromatin immunoprecipitation, and we found a strong colocalization of L2 and TBX2 in HPV16-positive cervical intraepithelial neoplasia (CIN) I-II tissue sections. These results suggest that TBX2/3 might play a role in the regulation of HPV gene expression during the viral life cycle.
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11
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Oyamada M, Takebe K, Oyamada Y. Regulation of connexin expression by transcription factors and epigenetic mechanisms. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1828:118-33. [PMID: 22244842 DOI: 10.1016/j.bbamem.2011.12.031] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 12/17/2011] [Accepted: 12/27/2011] [Indexed: 01/24/2023]
Abstract
Gap junctions are specialized cell-cell junctions that directly link the cytoplasm of neighboring cells. They mediate the direct transfer of metabolites and ions from one cell to another. Discoveries of human genetic disorders due to mutations in gap junction protein (connexin [Cx]) genes and experimental data on connexin knockout mice provide direct evidence that gap junctional intercellular communication is essential for tissue functions and organ development, and that its dysfunction causes diseases. Connexin-related signaling also involves extracellular signaling (hemichannels) and non-channel intracellular signaling. Thus far, 21 human genes and 20 mouse genes for connexins have been identified. Each connexin shows tissue- or cell-type-specific expression, and most organs and many cell types express more than one connexin. Connexin expression can be regulated at many of the steps in the pathway from DNA to RNA to protein. In recent years, it has become clear that epigenetic processes are also essentially involved in connexin gene expression. In this review, we summarize recent knowledge on regulation of connexin expression by transcription factors and epigenetic mechanisms including histone modifications, DNA methylation, and microRNA. This article is part of a Special Issue entitled: The communicating junctions, roles and dysfunctions.
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Affiliation(s)
- Masahito Oyamada
- Department of Food Science and Human Nutrition, Fuji Women's University, Ishikarishi, Japan.
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12
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Talhouk RS, Khalil AA, Bajjani R, Rahme GJ, El-Sabban ME. Gap junctions mediate STAT5-independent β-casein expression in CID-9 mammary epithelial cells. ACTA ACUST UNITED AC 2011; 18:104-16. [DOI: 10.3109/15419061.2011.639468] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Rabih S. Talhouk
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Antoine A. Khalil
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Rachid Bajjani
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Gilbert J. Rahme
- Department of Biology, American University of Beirut, Beirut, Lebanon
| | - Marwan E. El-Sabban
- Department of Human Morphology, American University of Beirut, Beirut, Lebanon
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13
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Batra N, Kar R, Jiang JX. Gap junctions and hemichannels in signal transmission, function and development of bone. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1909-18. [PMID: 21963408 DOI: 10.1016/j.bbamem.2011.09.018] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Revised: 09/03/2011] [Accepted: 09/15/2011] [Indexed: 10/17/2022]
Abstract
Gap junctional intercellular communication (GJIC) mediated by connexins, in particular connexin 43 (Cx43), plays important roles in regulating signal transmission among different bone cells and thereby regulates development, differentiation, modeling and remodeling of the bone. GJIC regulates osteoblast formation, differentiation, survival and apoptosis. Osteoclast formation and resorptive ability are also reported to be modulated by GJIC. Furthermore, osteocytes utilize GJIC to coordinate bone remodeling in response to anabolic factors and mechanical loading. Apart from gap junctions, connexins also form hemichannels, which are localized on the cell surface and function independently of the gap junction channels. Both these channels mediate the transfer of molecules smaller than 1.2kDa including small ions, metabolites, ATP, prostaglandin and IP(3). The biological importance of the communication mediated by connexin-forming channels in bone development is revealed by the low bone mass and osteoblast dysfunction in the Cx43-null mice and the skeletal malformations observed in occulodentodigital dysplasia (ODDD) caused by mutations in the Cx43 gene. The current review summarizes the role of gap junctions and hemichannels in regulating signaling, function and development of bone cells. This article is part of a Special Issue entitled: The Communicating junctions, composition, structure and characteristics.
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Affiliation(s)
- Nidhi Batra
- Department of Biochemistry, University of Texas Health Science Center, San Antonio, TX, USA
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Boogerd CJJ, Wong LYE, van den Boogaard M, Bakker ML, Tessadori F, Bakkers J, 't Hoen PAC, Moorman AF, Christoffels VM, Barnett P. Sox4 mediates Tbx3 transcriptional regulation of the gap junction protein Cx43. Cell Mol Life Sci 2011; 68:3949-61. [PMID: 21538160 PMCID: PMC3214269 DOI: 10.1007/s00018-011-0693-7] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 12/01/2010] [Accepted: 04/14/2011] [Indexed: 11/28/2022]
Abstract
Tbx3, a T-box transcription factor, regulates key steps in development of the heart and other organ systems. Here, we identify Sox4 as an interacting partner of Tbx3. Pull-down and nuclear retention assays verify this interaction and in situ hybridization reveals Tbx3 and Sox4 to co-localize extensively in the embryo including the atrioventricular and outflow tract cushion mesenchyme and a small area of interventricular myocardium. Tbx3, SOX4, and SOX2 ChIP data, identify a region in intron 1 of Gja1 bound by all tree proteins and subsequent ChIP experiments verify that this sequence is bound, in vivo, in the developing heart. In a luciferase reporter assay, this element displays a synergistic antagonistic response to co-transfection of Tbx3 and Sox4 and in vivo, in zebrafish, drives expression of a reporter in the heart, confirming its function as a cardiac enhancer. Mechanistically, we postulate that Sox4 is a mediator of Tbx3 transcriptional activity.
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Affiliation(s)
- C J J Boogerd
- Heart Failure Research Centre, Academic Medical Centre, University of Amsterdam, The Netherlands
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15
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Vance KW, Shaw HM, Rodriguez M, Ott S, Goding CR. The retinoblastoma protein modulates Tbx2 functional specificity. Mol Biol Cell 2010; 21:2770-9. [PMID: 20534814 PMCID: PMC2912361 DOI: 10.1091/mbc.e09-12-1029] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
This study demonstrates that Tbx2 binds Rb1. The interaction with Rb1 increases Tbx2 DNA-binding activity and enhances the ability of Tbx2 to repress transcription. The results show that Tbx2 regulates the expression of genes involved in cell division and DNA replication and that Rb1 modulates Tbx2 target gene recognition and specificity. Tbx2 is a member of a large family of transcription factors defined by homology to the T-box DNA-binding domain. Tbx2 plays a key role in embryonic development, and in cancer through its capacity to suppress senescence and promote invasiveness. Despite its importance, little is known of how Tbx2 is regulated or how it achieves target gene specificity. Here we show that Tbx2 specifically associates with active hypophosphorylated retinoblastoma protein (Rb1), a known regulator of many transcription factors involved in cell cycle progression and cellular differentiation, but not with the Rb1-related proteins p107 or p130. The interaction with Rb1 maps to a domain immediately carboxy-terminal to the T-box and enhances Tbx2 DNA binding and transcriptional repression. Microarray analysis of melanoma cells expressing inducible dominant-negative Tbx2, comprising the T-box and either an intact or mutated Rb1 interaction domain, shows that Tbx2 regulates the expression of many genes involved in cell cycle control and that a mutation which disrupts the Rb1-Tbx2 interaction also affects Tbx2 target gene selectivity. Taken together, the data show that Rb1 is an important determinant of Tbx2 functional specificity.
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Affiliation(s)
- Keith W Vance
- Department of Systems Biology, Biomedical Research Institute, University of Warwick, Coventry, CV4 7AL, United Kingdom.
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16
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Abrahams A, Parker MI, Prince S. The T-box transcription factor Tbx2: its role in development and possible implication in cancer. IUBMB Life 2010; 62:92-102. [PMID: 19960541 DOI: 10.1002/iub.275] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Tbx2 is a member of the T-box family of transcription factors that are crucial in embryonic development. Recent studies suggest that T-box factors may also play a role in controlling cell cycle progression and in the genesis of cancer. Tbx2 has been implicated in several developmental processes such as coordinating cell fate, patterning and morphogenesis of a wide range of tissues and organs including limbs, kidneys, lungs, mammary glands, heart, and craniofacial structures. Importantly, Tbx2 is overexpressed in several cancers including melanoma, small cell lung carcinoma, breast, pancreatic, liver, and bladder cancers and can suppress senescence, a cellular process, which serves as a barrier to cancer development. This review presents a state of the art overview of the role and regulation of Tbx2 in early embryonic development and in cancer.
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Affiliation(s)
- Amaal Abrahams
- Faculty of Health Sciences, Department of Human Biology, University of Cape Town, Observatory, Cape Town, South Africa
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17
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Hohenlohe PA, Bassham S, Etter PD, Stiffler N, Johnson EA, Cresko WA. Population genomics of parallel adaptation in threespine stickleback using sequenced RAD tags. PLoS Genet 2010; 6:e1000862. [PMID: 20195501 PMCID: PMC2829049 DOI: 10.1371/journal.pgen.1000862] [Citation(s) in RCA: 1112] [Impact Index Per Article: 79.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2009] [Accepted: 01/28/2010] [Indexed: 11/19/2022] Open
Abstract
Next-generation sequencing technology provides novel opportunities for gathering genome-scale sequence data in natural populations, laying the empirical foundation for the evolving field of population genomics. Here we conducted a genome scan of nucleotide diversity and differentiation in natural populations of threespine stickleback (Gasterosteus aculeatus). We used Illumina-sequenced RAD tags to identify and type over 45,000 single nucleotide polymorphisms (SNPs) in each of 100 individuals from two oceanic and three freshwater populations. Overall estimates of genetic diversity and differentiation among populations confirm the biogeographic hypothesis that large panmictic oceanic populations have repeatedly given rise to phenotypically divergent freshwater populations. Genomic regions exhibiting signatures of both balancing and divergent selection were remarkably consistent across multiple, independently derived populations, indicating that replicate parallel phenotypic evolution in stickleback may be occurring through extensive, parallel genetic evolution at a genome-wide scale. Some of these genomic regions co-localize with previously identified QTL for stickleback phenotypic variation identified using laboratory mapping crosses. In addition, we have identified several novel regions showing parallel differentiation across independent populations. Annotation of these regions revealed numerous genes that are candidates for stickleback phenotypic evolution and will form the basis of future genetic analyses in this and other organisms. This study represents the first high-density SNP-based genome scan of genetic diversity and differentiation for populations of threespine stickleback in the wild. These data illustrate the complementary nature of laboratory crosses and population genomic scans by confirming the adaptive significance of previously identified genomic regions, elucidating the particular evolutionary and demographic history of such regions in natural populations, and identifying new genomic regions and candidate genes of evolutionary significance.
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Affiliation(s)
- Paul A. Hohenlohe
- Center for Ecology and Evolutionary Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Susan Bassham
- Center for Ecology and Evolutionary Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Paul D. Etter
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America
| | - Nicholas Stiffler
- Genomics Core Facility, University of Oregon, Eugene, Oregon, United States of America
| | - Eric A. Johnson
- Institute of Molecular Biology, University of Oregon, Eugene, Oregon, United States of America
| | - William A. Cresko
- Center for Ecology and Evolutionary Biology, University of Oregon, Eugene, Oregon, United States of America
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18
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Population genomics of parallel adaptation in threespine stickleback using sequenced RAD tags. PLoS Genet 2010. [PMID: 20195501 DOI: 10.1371/journal.pgen.1000862.] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Next-generation sequencing technology provides novel opportunities for gathering genome-scale sequence data in natural populations, laying the empirical foundation for the evolving field of population genomics. Here we conducted a genome scan of nucleotide diversity and differentiation in natural populations of threespine stickleback (Gasterosteus aculeatus). We used Illumina-sequenced RAD tags to identify and type over 45,000 single nucleotide polymorphisms (SNPs) in each of 100 individuals from two oceanic and three freshwater populations. Overall estimates of genetic diversity and differentiation among populations confirm the biogeographic hypothesis that large panmictic oceanic populations have repeatedly given rise to phenotypically divergent freshwater populations. Genomic regions exhibiting signatures of both balancing and divergent selection were remarkably consistent across multiple, independently derived populations, indicating that replicate parallel phenotypic evolution in stickleback may be occurring through extensive, parallel genetic evolution at a genome-wide scale. Some of these genomic regions co-localize with previously identified QTL for stickleback phenotypic variation identified using laboratory mapping crosses. In addition, we have identified several novel regions showing parallel differentiation across independent populations. Annotation of these regions revealed numerous genes that are candidates for stickleback phenotypic evolution and will form the basis of future genetic analyses in this and other organisms. This study represents the first high-density SNP-based genome scan of genetic diversity and differentiation for populations of threespine stickleback in the wild. These data illustrate the complementary nature of laboratory crosses and population genomic scans by confirming the adaptive significance of previously identified genomic regions, elucidating the particular evolutionary and demographic history of such regions in natural populations, and identifying new genomic regions and candidate genes of evolutionary significance.
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19
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Behesti H, Papaioannou VE, Sowden JC. Loss of Tbx2 delays optic vesicle invagination leading to small optic cups. Dev Biol 2009; 333:360-72. [PMID: 19576202 DOI: 10.1016/j.ydbio.2009.06.026] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2009] [Revised: 06/19/2009] [Accepted: 06/22/2009] [Indexed: 01/05/2023]
Abstract
Tbx2 is a T-box transcription factor gene that is dynamically expressed in the presumptive retina during optic vesicle invagination. Several findings implicate Tbx2 in cell cycle regulation, including its overexpression in tumours and regulation of proliferation during heart development. We investigated the role of Tbx2 in optic cup formation by analysing mice with a targeted homozygous mutation in Tbx2. Loss of Tbx2 caused a reduced presumptive retinal volume due to increased apoptosis, and a delay in ventral optic vesicle invagination leading to the formation of small and abnormally shaped optic cups. Tbx2 is essential for maintenance, but not induction of expression of the dorsal retinal determinant, Tbx5, and acts downstream of Bmp4, a dorsally expressed gene implicated in human microphthalmia. The small retina showed a hypocellular ventral region, loss of Fgf15, normally expressed in proliferating central retinal cells, and increased numbers of mitotic cells in the dorsal region, indicating that Tbx2 is required for normal growth and development across the D-V axis. Dorsal expression of potential regulators of retinal growth, Cyp1b1 and Cx43, and the topographic guidance molecule ephrinB2, was increased, and intraretinal axons were disorganised resulting in a failure of optic nerve formation. Our data provide evidence that Tbx2 is required for proper optic cup formation and plays a critical early role in regulating regional retinal growth and the acquisition of shape during optic vesicle invagination.
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Affiliation(s)
- Hourinaz Behesti
- Developmental Biology Unit, UCL Institute of Child Health, University College London, London, WC1N 1EH, UK
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20
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Boogerd KJ, Wong LYE, Christoffels VM, Klarenbeek M, Ruijter JM, Moorman AFM, Barnett P. Msx1 and Msx2 are functional interacting partners of T-box factors in the regulation of Connexin43. Cardiovasc Res 2008; 78:485-93. [PMID: 18285513 DOI: 10.1093/cvr/cvn049] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
AIMS T-box factors Tbx2 and Tbx3 play key roles in the development of the cardiac conduction system, atrioventricular canal, and outflow tract of the heart. They regulate the gap-junction-encoding gene Connexin43 (Cx43) and other genes critical for heart development and function. Discovering protein partners of Tbx2 and Tbx3 will shed light on the mechanisms by which these factors regulate these gene programs. METHODS AND RESULTS Employing an yeast 2-hybrid screen and subsequent in vitro pull-down experiments we demonstrate that muscle segment homeobox genes Msx1 and Msx2 are able to bind the cardiac T-box proteins Tbx2, Tbx3, and Tbx5. This interaction, as that of the related Nkx2.5 protein, is supported by the T-box and homeodomain alone. Overlapping spatiotemporal expression patterns of Msx1 and Msx2 together with the T-box genes during cardiac development in mouse and chicken underscore the biological significance of this interaction. We demonstrate that Msx proteins together with Tbx2 and Tbx3 suppress Cx43 promoter activity and down regulate Cx43 gene activity in a rat heart-derived cell line. Using chromatin immunoprecipitation analysis we demonstrate that Msx1 can bind the Cx43 promoter at a conserved binding site located in close proximity to a previously defined T-box binding site, and that the activity of Msx proteins on this promoter appears dependent in the presence of Tbx3. CONCLUSION Msx1 and Msx2 can function in concert with the T-box proteins to suppress Cx43 and other working myocardial genes.
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Affiliation(s)
- Kees-Jan Boogerd
- Department of Anatomy and Embryology, Heart Failure Research Centre, Academic Medical Centre, University of Amsterdam, Meibergdreef 9, 1105AZ Amsterdam, The Netherlands
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21
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Hoogaars WM, Engel A, Brons JF, Verkerk AO, de Lange FJ, Wong LE, Bakker ML, Clout DE, Wakker V, Barnett P, Ravesloot JH, Moorman AF, Verheijck EE, Christoffels VM. Tbx3 controls the sinoatrial node gene program and imposes pacemaker function on the atria. Genes Dev 2007; 21:1098-112. [PMID: 17473172 PMCID: PMC1855235 DOI: 10.1101/gad.416007] [Citation(s) in RCA: 288] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The sinoatrial node initiates the heartbeat and controls the rate and rhythm of contraction, thus serving as the pacemaker of the heart. Despite the crucial role of the sinoatrial node in heart function, the mechanisms that underlie its specification and formation are not known. Tbx3, a transcriptional repressor required for development of vertebrates, is expressed in the developing conduction system. Here we show that Tbx3 expression delineates the sinoatrial node region, which runs a gene expression program that is distinct from that of the bordering atrial cells. We found lineage segregation of Tbx3-negative atrial and Tbx3-positive sinoatrial node precursor cells as soon as cardiac cells turn on the atrial gene expression program. Tbx3 deficiency resulted in expansion of expression of the atrial gene program into the sinoatrial node domain, and partial loss of sinoatrial node-specific gene expression. Ectopic expression of Tbx3 in mice revealed that Tbx3 represses the atrial phenotype and imposes the pacemaker phenotype on the atria. The mice displayed arrhythmias and developed functional ectopic pacemakers. These data identify a Tbx3-dependent pathway for the specification and formation of the sinoatrial node, and show that Tbx3 regulates the pacemaker gene expression program and phenotype.
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Affiliation(s)
- Willem M.H. Hoogaars
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Angela Engel
- Department of Physiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Janynke F. Brons
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Arie O. Verkerk
- Department of Physiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Frederik J. de Lange
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - L.Y. Elaine Wong
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Martijn L. Bakker
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Danielle E. Clout
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Vincent Wakker
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Phil Barnett
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Jan Hindrik Ravesloot
- Department of Physiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Antoon F.M. Moorman
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - E. Etienne Verheijck
- Department of Physiology, Heart Failure Research Center, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
| | - Vincent M. Christoffels
- Department of Anatomy and Embryology, Academic Medical Center, University of Amsterdam, 1105 AZ Amsterdam, The Netherlands
- Corresponding author.E-MAIL ; FAX 31-20-6976177
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Levin M. Gap junctional communication in morphogenesis. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2007; 94:186-206. [PMID: 17481700 PMCID: PMC2292839 DOI: 10.1016/j.pbiomolbio.2007.03.005] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Gap junctions permit the direct passage of small molecules from the cytosol of one cell to that of its neighbor, and thus form a system of cell-cell communication that exists alongside familiar secretion/receptor signaling. Because of the rich potential for regulation of junctional conductance, and directional and molecular gating (specificity), gap junctional communication (GJC) plays a crucial role in many aspects of normal tissue physiology. However, the most exciting role for GJC is in the regulation of information flow that takes place during embryonic development, regeneration, and tumor progression. The molecular mechanisms by which GJC establishes local and long-range instructive morphogenetic cues are just beginning to be understood. This review summarizes the current knowledge of the involvement of GJC in the patterning of both vertebrate and invertebrate systems and discusses in detail several morphogenetic systems in which the properties of this signaling have been molecularly characterized. One model consistent with existing data in the fields of vertebrate left-right patterning and anterior-posterior polarity in flatworm regeneration postulates electrophoretically guided movement of small molecule morphogens through long-range GJC paths. The discovery of mechanisms controlling embryonic and regenerative GJC-mediated signaling, and identification of the downstream targets of GJC-permeable molecules, represent exciting next areas of research in this fascinating field.
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Affiliation(s)
- Michael Levin
- Forsyth Center for Regenerative and Devlopmental Biology, Forsyth Institute, and Developmental Biology Department, Harvard School of Dental Medicine, Boston, MA 02115, USA.
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Cis-motifs upstream of the transcription and translation initiation sites are effectively revealed by their positional disequilibrium in eukaryote genomes using frequency distribution curves. BMC Bioinformatics 2006; 7:522. [PMID: 17137509 PMCID: PMC1698937 DOI: 10.1186/1471-2105-7-522] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Accepted: 11/30/2006] [Indexed: 11/24/2022] Open
Abstract
Background The discovery of cis-regulatory motifs still remains a challenging task even though the number of sequenced genomes is constantly growing. Computational analyses using pattern search algorithms have been valuable in phylogenetic footprinting approaches as have expression profile experiments to predict co-occurring motifs. Surprisingly little is known about the nature of cis-regulatory element (CRE) distribution in promoters. Results In this paper we used the Motif Mapper open-source collection of visual basic scripts for the analysis of motifs in any aligned set of DNA sequences. We focused on promoter motif distribution curves to identify positional over-representation of DNA motifs. Using differentially aligned datasets from the model species Arabidopsis thaliana, Caenorhabditis elegans, Drosophila melanogaster and Saccharomyces cerevisiae, we convincingly demonstrated the importance of the position and orientation for motif discovery. Analysis with known CREs and all possible hexanucleotides showed that some functional elements gather close to the transcription and translation initiation sites and that elements other than the TATA-box motif are conserved between eukaryote promoters. While a high background frequency usually decreases the effectiveness of such an enumerative investigation, we improved our analysis by conducting motif distribution maps using large datasets. Conclusion This is the first study to reveal positional over-representation of CREs and promoter motifs in a cross-species approach. CREs and motifs shared between eukaryotic promoters support the observation that an eukaryotic promoter structure has been conserved throughout evolutionary time. Furthermore, with the information on positional enrichment of a motif or a known functional CRE, it is possible to get a more detailed insight into where an element appears to function. This in turn might accelerate the in depth examination of known and yet unknown cis-regulatory sequences in the laboratory.
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Oyamada M, Oyamada Y, Takamatsu T. Regulation of connexin expression. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2005; 1719:6-23. [PMID: 16359940 DOI: 10.1016/j.bbamem.2005.11.002] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2005] [Revised: 10/29/2005] [Accepted: 11/02/2005] [Indexed: 01/22/2023]
Abstract
Gap junctions contain cell-cell communicating channels that consist of multimeric proteins called connexins and mediate the exchange of low-molecular-weight metabolites and ions between contacting cells. Gap junctional communication has long been hypothesized to play a crucial role in the maintenance of homeostasis, morphogenesis, cell differentiation, and growth control in multicellular organisms. The recent discovery that human genetic disorders are associated with mutations in connexin genes and experimental data on connexin knockout mice have provided direct evidence that gap junctional communication is essential for tissue functions and organ development. Thus far, 21 human genes and 20 mouse genes for connexins have been identified. Each connexin shows tissue- or cell-type-specific expression, and most organs and many cell types express more than one connexin. Cell coupling via gap junctions is dependent on the specific pattern of connexin gene expression. This pattern of gene expression is altered during development and in several pathological conditions resulting in changes of cell coupling. Connexin expression can be regulated at many of the steps in the pathway from DNA to RNA to protein. However, transcriptional control is one of the most important points. In this review, we summarize recent knowledge on transcriptional regulation of connexin genes by describing the structure of connexin genes and transcriptional factors that regulate connexin expression.
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Affiliation(s)
- Masahito Oyamada
- Department of Pathology and Cell Regulation, Kyoto Prefectural University of Medicine, Kawaramachi Hirokoji, Kamigyo-ku, Kyoto 602-8566, Japan.
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Singh MK, Christoffels VM, Dias JM, Trowe MO, Petry M, Schuster-Gossler K, Bürger A, Ericson J, Kispert A. Tbx20 is essential for cardiac chamber differentiation and repression of Tbx2. Development 2005; 132:2697-707. [PMID: 15901664 DOI: 10.1242/dev.01854] [Citation(s) in RCA: 157] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Tbx20, a member of the T-box family of transcriptional regulators, shows evolutionary conserved expression in the developing heart. In the mouse, Tbx20 is expressed in the cardiac crescent, then in the endocardium and myocardium of the linear and looped heart tube before it is restricted to the atrioventricular canal and outflow tract in the multi-chambered heart. Here, we show that Tbx20 is required for progression from the linear heart tube to a multi-chambered heart. Mice carrying a targeted mutation of Tbx20 show early embryonic lethality due to hemodynamic failure. A linear heart tube with normal anteroposterior patterning is established in the mutant. The tube does not elongate, indicating a defect in recruitment of mesenchyme from the secondary heart field, even though markers of the secondary heart field are not affected. Furthermore, dorsoventral patterning of the tube, formation of working myocardium, looping, and further differentiation and morphogenesis fail. Instead, Tbx2, Bmp2 and vinexin alpha (Sh3d4), genes normally restricted to regions of primary myocardium and lining endocardium, are ectopically expressed in the linear heart tube of Tbx20 mutant embryos. Because Tbx2 is both necessary and sufficient to repress chamber differentiation (Christoffels et al., 2004a; Harrelson et al., 2004), Tbx20 may ensure progression to a multi-chambered heart by repressing Tbx2 in the myocardial precursor cells of the linear heart tube destined to form the chambers.
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Affiliation(s)
- Manvendra K Singh
- Institut für Molekularbiologie, Medizinische Hochschule Hannover, 30625 Hannover, Germany
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Harrelson Z, Kelly RG, Goldin SN, Gibson-Brown JJ, Bollag RJ, Silver LM, Papaioannou VE. Tbx2 is essential for patterning the atrioventricular canal and for morphogenesis of the outflow tract during heart development. Development 2004; 131:5041-52. [PMID: 15459098 DOI: 10.1242/dev.01378] [Citation(s) in RCA: 220] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Tbx2 is a member of the T-box transcription factor gene family, and is expressed in a variety of tissues and organs during embryogenesis. In the developing heart, Tbx2 is expressed in the outflow tract, inner curvature, atrioventricular canal and inflow tract, corresponding to a myocardial zone that is excluded from chamber differentiation at 9.5 days post coitus (dpc). We have used targeted mutagenesis in mice to investigate Tbx2 function. Mice heterozygous for a Tbx2 null mutation appear normal but homozygous embryos reveal a crucial role for Tbx2 during cardiac development. Morphological defects are observed in development of the atrioventricular canal and septation of the outflow tract. Molecular analysis reveals that Tbx2 is required to repress chamber differentiation in the atrioventricular canal at 9.5 dpc. Analysis of homozygous mutants also highlights a role for Tbx2 during hindlimb digit development. Despite evidence that TBX2 negatively regulates the cell cycle control genes Cdkn2a, Cdkn2b and Cdkn1a in cultured cells, there is no evidence that loss of Tbx2 function during mouse development results in increased levels of p19(ARF), p16(INK4a), p15(INK4b) or p21 expression in vivo, nor is there evidence for a genetic interaction between Tbx2 and p53.
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Affiliation(s)
- Zachary Harrelson
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York, NY 10032, USA
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Abstract
T-box factors are critical regulators of embryonic development and have been implicated in several human diseases. This primer describes the basics of how T-box factors work and features a discussion of the state of T-box gene research with three experts in the field.
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Affiliation(s)
- Julie C Kiefer
- Huntsman Cancer Institute, University of Utah, 2000 Circle of Hope, Salt Lake City, UT 84112, USA.
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