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He Z, Liu X, Liu X, Cui L, Yuan Y, Zhang H, Chen Y, Tao Y, Yu Z. The role of MEG3 in the proliferation of palatal mesenchymal cells is related to the TGFβ/Smad pathway in TCDD inducing cleft palate. Toxicol Appl Pharmacol 2021; 419:115517. [PMID: 33812962 DOI: 10.1016/j.taap.2021.115517] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Revised: 03/21/2021] [Accepted: 03/30/2021] [Indexed: 11/16/2022]
Abstract
Cleft palate (CP) is a common birth defect with a high incidence of occurrence in humans. The 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) is a highly toxic halogenated aromatic hydrocarbon, with a strong CP effect on mice. Increasing recent evidences have shown that long-noncoding RNAs (lncRNAs) play an important role in several diseases, including CP. However, there is a paucity of studies on the role of lncRNA MEG3 in the occurrence and development of TCDD-induced CP. In this study, the relationship between MEG3 and the proliferation of palatal mesenchymal cells and the underlying molecular mechanism were studied by establishing fetal CP with TCDD (64 μg/kg) in C57BL/6N mice. The results revealed that MEG3 was highly expressed during the critical period of CP formation and that the fetal mesenchymal proliferation was significantly inhibited at certain critical periods in the mice receiving TCDD. In addition, we noted a possibility of a crosstalk between MEG3 and the TGF-β/Smad pathway, such that the inhibition of the TGF-β/Smad pathway was induced by TCDD. Cumulatively, our study suggests that TCDD-induced CP may be caused by MEG3 inhibition of the proliferation of palatal mesenchymal cells involving the TGFβ/Smad pathway, which may provide a novel perspective to understand the pathogenesis of CP.
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Affiliation(s)
- Zhidong He
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - XinXin Liu
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Xiaozhuan Liu
- Center for Clinical Single-Cell Biomedicine, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Lingling Cui
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Yangyang Yuan
- The third affiliated Hospital, Zhengzhou University, Zhengzhou, Henan, China
| | - Huanhuan Zhang
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Yao Chen
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Yuchang Tao
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China; Center for Clinical Single-Cell Biomedicine, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Zengli Yu
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China.
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Teino I, Matvere A, Pook M, Varik I, Pajusaar L, Uudeküll K, Vaher H, Trei A, Kristjuhan A, Org T, Maimets T. Impact of AHR Ligand TCDD on Human Embryonic Stem Cells and Early Differentiation. Int J Mol Sci 2020; 21:E9052. [PMID: 33260776 PMCID: PMC7731104 DOI: 10.3390/ijms21239052] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 11/20/2020] [Accepted: 11/26/2020] [Indexed: 12/17/2022] Open
Abstract
Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, which mediates the effects of a variety of environmental stimuli in multiple tissues. Recent advances in AHR biology have underlined its importance in cells with high developmental potency, including pluripotent stem cells. Nonetheless, there is little data on AHR expression and its role during the initial stages of stem cell differentiation. The purpose of this study was to investigate the temporal pattern of AHR expression during directed differentiation of human embryonic stem cells (hESC) into neural progenitor, early mesoderm and definitive endoderm cells. Additionally, we investigated the effect of the AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the gene expression profile in hESCs and differentiated cells by RNA-seq, accompanied by identification of AHR binding sites by ChIP-seq and epigenetic landscape analysis by ATAC-seq. We showed that AHR is differentially regulated in distinct lineages. We provided evidence that TCDD alters gene expression patterns in hESCs and during early differentiation. Additionally, we identified novel potential AHR target genes, which expand our understanding on the role of this protein in different cell types.
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Affiliation(s)
- Indrek Teino
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Antti Matvere
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Martin Pook
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Inge Varik
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Laura Pajusaar
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Keyt Uudeküll
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Helen Vaher
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Annika Trei
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Arnold Kristjuhan
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
| | - Tõnis Org
- Chair of Biotechnology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia;
- Institute of Genomics, University of Tartu, Riia 23b, 51010 Tartu, Estonia
| | - Toivo Maimets
- Chair of Cell Biology, Institute of Molecular and Cell Biology, University of Tartu, Riia 23, 51010 Tartu, Estonia; (A.M.); (M.P.); (I.V.); (L.P.); (K.U.); (H.V.); (A.T.); (A.K.); (T.M.)
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3
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Garland MA, Reynolds K, Zhou CJ. Environmental mechanisms of orofacial clefts. Birth Defects Res 2020; 112:1660-1698. [PMID: 33125192 PMCID: PMC7902093 DOI: 10.1002/bdr2.1830] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 10/07/2020] [Accepted: 10/13/2020] [Indexed: 12/11/2022]
Abstract
Orofacial clefts (OFCs) are among the most common birth defects and impart a significant burden on afflicted individuals and their families. It is increasingly understood that many nonsyndromic OFCs are a consequence of extrinsic factors, genetic susceptibilities, and interactions of the two. Therefore, understanding the environmental mechanisms of OFCs is important in the prevention of future cases. This review examines the molecular mechanisms associated with environmental factors that either protect against or increase the risk of OFCs. We focus on essential metabolic pathways, environmental signaling mechanisms, detoxification pathways, behavioral risk factors, and biological hazards that may disrupt orofacial development.
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Affiliation(s)
- Michael A. Garland
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817
| | - Kurt Reynolds
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) graduate group, University of California, Davis, CA 95616
| | - Chengji J. Zhou
- Department of Biochemistry and Molecular Medicine, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Institute for Pediatric Regenerative Medicine of Shriners Hospitals for Children, University of California at Davis, School of Medicine, Sacramento, CA 95817
- Biochemistry, Molecular, Cellular, and Developmental Biology (BMCDB) graduate group, University of California, Davis, CA 95616
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4
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Oliver JD, Turner EC, Halpern LR, Jia S, Schneider P, D'Souza RN. Molecular Diagnostics and In Utero Therapeutics for Orofacial Clefts. J Dent Res 2020; 99:1221-1227. [PMID: 32609569 DOI: 10.1177/0022034520936245] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Orofacial clefts and their management impose a substantial burden on patients, on their families, and on the health system. Under the current standard of care, affected patients are subjected to a lifelong journey of corrective surgeries and multidisciplinary management to replace bone and soft tissues, as well as restore esthetics and physiologic functions while restoring self-esteem and psychological health. Hence, a better understanding of the dynamic interplay of molecular signaling pathways at critical phases of palate development is necessary to pioneer novel prenatal interventions. Such pathways include transforming growth factor-β (Tgfβ), sonic hedgehog (Shh), wingless-integrated site (Wnt)/β-catenin, bone morphogenetic protein (Bmp), and fibroblast growth factor (Fgf) and its associated receptors, among others. Here, we summarize commonly used surgical methods used to correct cleft defects postnatally. We also review the advances made in prenatal diagnostics of clefts through imaging and genomics and the various in utero surgical corrections that have been attempted thus far. An overview of how key mediators of signaling that drive palatogenesis are emphasized in the context of the framework and rationale for the development and testing of therapeutics in animal model systems and in humans is provided. The pros and cons of in utero therapies that can potentially restore molecular homeostasis needed for the proper growth and fusion of palatal shelves are presented. The theme advanced throughout this review is the need to develop preclinical molecular therapies that could ultimately be translated into human trials that can correct orofacial clefts at earlier stages of development.
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Affiliation(s)
- J D Oliver
- School of Medicine and School of Dentistry, University of Utah Health, Salt Lake City, UT, USA.,Department of Biomedical Engineering, College of Engineering, University of Utah, Salt Lake City, UT, USA
| | - E C Turner
- University of Western Australia Dental School, Perth, Western Australia
| | - L R Halpern
- School of Medicine and School of Dentistry, University of Utah Health, Salt Lake City, UT, USA
| | - S Jia
- School of Medicine and School of Dentistry, University of Utah Health, Salt Lake City, UT, USA
| | - P Schneider
- Department of Biochemistry, University of Lausanne, Epalinges, Switzerland
| | - R N D'Souza
- School of Medicine and School of Dentistry, University of Utah Health, Salt Lake City, UT, USA.,Department of Biomedical Engineering, College of Engineering, University of Utah, Salt Lake City, UT, USA.,University of Utah, Departments of Neurobiology and Anatomy, Pathology, and Surgery, Salt Lake City, UT, USA
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5
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Vitamin B12 and folic acid alleviate symptoms of nutritional deficiency by antagonizing aryl hydrocarbon receptor. Proc Natl Acad Sci U S A 2020; 117:15837-15845. [PMID: 32571957 DOI: 10.1073/pnas.2006949117] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Despite broad appreciation of their clinical utility, it has been unclear how vitamin B12 and folic acid (FA) function at the molecular level to directly prevent their hallmark symptoms of deficiency like anemia or birth defects. To this point, B12 and FA have largely been studied as cofactors for enzymes in the one-carbon (1C) cycle in facilitating the de novo generation of nucleotides and methylation of DNA and protein. Here, we report that B12 and FA function as natural antagonists of aryl hydrocarbon receptor (AhR). Our studies indicate that B12 and FA bind AhR directly as competitive antagonists, blocking AhR nuclear localization, XRE binding, and target gene induction mediated by AhR agonists like 2,3,7,8-tetrachlorodibenzodioxin (TCDD) and 6-formylindolo[3,2-b]carbazole (FICZ). In mice, TCDD treatment replicated many of the hallmark symptoms of B12/FA deficiency and cotreatment with aryl hydrocarbon portions of B12/FA rescued mice from these toxic effects. Moreover, we found that B12/FA deficiency in mice induces AhR transcriptional activity and accumulation of erythroid progenitors and that it may do so in an AhR-dependent fashion. Consistent with these results, we observed that human cancer samples with deficient B12/FA uptake demonstrated higher transcription of AhR target genes and lower transcription of pathways implicated in birth defects. In contrast, there was no significant difference observed between samples with mutated and intact 1C cycle proteins. Thus, we propose a model in which B12 and FA blunt the effect of natural AhR agonists at baseline to prevent the symptoms that arise with AhR overactivation.
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Liu X, Li X, Tao Y, Li N, Ji M, Zhang X, Chen Y, He Z, Yu K, Yu Z. TCDD inhibited the osteogenic differentiation of human fetal palatal mesenchymal cells through AhR and BMP-2/TGF-β/Smad signaling. Toxicology 2019; 431:152353. [PMID: 31887333 DOI: 10.1016/j.tox.2019.152353] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 12/17/2019] [Accepted: 12/26/2019] [Indexed: 12/13/2022]
Abstract
Exposure to environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes cleft palate at high rates, but little is known about the underlying biological mechanisms. In the present study, we cultured osteoblasts from human fetal palate mesenchymal cells (hFPMCs) to explore the effects of TCDD on osteogenic differentiation. The results showed that TCDD significantly decreased cell proliferation, alkaline phosphatase (ALP) activity and calcium deposition. RNA analyses and protein detection demonstrated that TCDD downregulated a wide array of pro-osteogenic biomarkers. Further investigation of the underlying molecular mechanisms revealed that exposure to TCDD activated aryl hydrocarbon receptor (AhR) signaling and inhibited BMP-2/TGF-β1/Smad pathway molecules. The inactivation of AhR signaling using CRISPR/Cas9-mediated AhR deletion or by genetic siRNA knockdown significantly blocked the effects induced by TCDD, suggesting a critical role of AhR activation in the TCDD-mediated inhibition of hFPMC osteogenic differentiation. The cotreatment with TGF-β1 or BMP-2 and TCDD significantly relieved the activation of AhR and rescued the impairment of osteogenesis caused by TCDD. Taken together, our findings indicated that TCDD inhibited the osteogenic differentiation of hFPMCs via crosstalk between AhR and BMP-2/TGF-β1/Smad signaling pathway.
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Affiliation(s)
- Xiaozhuan Liu
- Center for Clinical Single-Cell Biomedicine, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Xue Li
- Center for Clinical Single-Cell Biomedicine, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Yuchang Tao
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Ning Li
- College of Food Science and Technology, Henan Agricultural University, China
| | - Mengmeng Ji
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Xiuli Zhang
- Division of Blood Vessel Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou, Henan, China
| | - Yao Chen
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Zhidong He
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Kailun Yu
- School of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Zengli Yu
- Center for Clinical Single-Cell Biomedicine, Henan Provincial People's Hospital, People's Hospital of Zhengzhou University, Zhengzhou, Henan, China; School of Public Health, Zhengzhou University, Zhengzhou, Henan, China.
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7
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Seelan RS, Pisano M, Greene RM. Nucleic acid methylation and orofacial morphogenesis. Birth Defects Res 2019; 111:1593-1610. [PMID: 31385455 DOI: 10.1002/bdr2.1564] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 07/17/2019] [Accepted: 07/19/2019] [Indexed: 12/19/2022]
Abstract
In this review, we highlight the current state of knowledge of the diverse roles nucleic acid methylation plays in the embryonic development of the orofacial region and how aberrant methylation may contribute to orofacial clefts. We also consider the role of methylation in the regulation of neural crest cell function as it pertains to orofacial ontogeny. Changes in DNA methylation, as a consequence of environmental effects, have been observed in the regulatory regions of several genes, potentially identifying new candidate genes for orofacial clefting and opening promising new avenues for further research. While the focus of this review is primarily on the nonsyndromic forms of orofacial clefting, syndromic forms are briefly discussed in the context of aberrant nucleic acid methylation.
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Affiliation(s)
- Ratnam S Seelan
- Department of Oral Immunology and Infectious Diseases, Division of Craniofacial Development and Anomalies, University of Louisville School of Dentistry, Louisville, Kentucky
| | - Michele Pisano
- Department of Oral Immunology and Infectious Diseases, Division of Craniofacial Development and Anomalies, University of Louisville School of Dentistry, Louisville, Kentucky
| | - Robert M Greene
- Department of Oral Immunology and Infectious Diseases, Division of Craniofacial Development and Anomalies, University of Louisville School of Dentistry, Louisville, Kentucky
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Li M, Bing S, Qian Z. [Influence of dexamethasone on the cell polarity and PAR complex of the embryonic epithelial cells in the palate]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2019; 36:9-16. [PMID: 29594989 DOI: 10.7518/hxkq.2018.01.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
OBJECTIVE This study aims to investigate whether dexamethasone (DEX) can down-regulate the PAR complex and disrupt the cell polarity in the palatal epithelium during palatal fusion. METHODS Pregnant rats were randomly divided into control and DEX groups, which were injected intraperitoneally with 0.9% sodium chloride (0.1 mL) and DEX (6 mg·kg ⁻¹), respectively, every day from E10 to E12. The palatal epithelial morphology was observed using hematoxylin and eosin staining and scanning electron microscopy. Immunofluorescence staining, Western Blot analysis, and real-time polymerase chain reaction were performed to detect the expression of PAR3, PAR6, and aPKC. RESULTS The incidence of cleft palate in DEX group (46.15%) was significantly higher than that in control group (3.92%), and the difference was statistically significant (χ2=24.335, P=0.00). DEX can also retard the growth of the palatal shelves and the short palatal shelves. The morphology and arrangement of MEE cells changed from polarized bilayer cells to nonpolarized monolayer ones. Additionally, the spherical structure decreased, which caused the cleft palate. PAR3 and PAR6 were only detected in the palatal epithelium, and aPKC was expressed in the palatal epithelium and mesenchyme. DEX can reduce the expression levels of PAR3, PAR6, and aPKC in the protein and gene levels. CONCLUSIONS DEX can down-regulate the complex gene expression in the MEE cells, thereby destroying the cell polarity and causing cleft palate.
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Affiliation(s)
- Ma Li
- Dept. of Stomatology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China;State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Shi Bing
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
| | - Zheng Qian
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & Dept. of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China
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Gao L, Xu J, Li X, Wang T, Wu W, Cao J. 2,3,7,8-Tetrachlorodibenzo-p-dioxin and TGFβ3-Mediated Mouse Embryonic Palatal Mesenchymal Cells. Dose Response 2019; 17:1559325818786822. [PMID: 30853873 PMCID: PMC6399763 DOI: 10.1177/1559325818786822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2018] [Accepted: 05/01/2018] [Indexed: 12/22/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a well-known environmental teratogenic effector for cleft palate. Transforming growth factor 3 (TGF-β3) is an essential growth factor for palatogenesis. The objective of this study is to clarify the effects of TCDD and TGF-β3 in mouse embryonic palatal mesenchymal (MEPM) cells. The effects of 10 nM TCDD, 10 ng/mL TGF-β3, or a combination of 10 nM TCDD and 10 ng/mL TGF-β3 on MEPM cells were revealed by cell and biological methods. With the increase in TCDD (0.5-10 nM), the expression of TGF-β3 increased, but at TCDD concentrations greater than 10 nM, the expression of TGF-β3 reduced. The viabilities of MEPM cells decreased in the 10 nM TCDD-treated group. But the viabilities increased in the 10 ng/mL TGF-β3-treated group, and the viabilities were intermediate in the group treated with a combination of 10 nM TCDD and 10 ng/mL TGF-β3. This phenomenon was the same as that of the motilities. In addition, we found that the expression of p-Smad2, p-Smad3,and Smad7 were increased by TCDD, TGF-β3, combination of TCDD and TGF-β3, but the expression of Smad4 were decreased by TCDD, TGF-β3, combination of TCDD and TGF-β3. These data revealed that TCDD and TGF-β3 interacted and affected MEPM cells.
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Affiliation(s)
- Liyun Gao
- Department of Toxicology, School of Public Health, Xinxiang Medical University, Xinxiang, People's Republic of China
| | - Jie Xu
- Department of Toxicology, School of Public Health, Xinxiang Medical University, Xinxiang, People's Republic of China
| | - Xiao Li
- Department of Toxicology, School of Public Health, Xinxiang Medical University, Xinxiang, People's Republic of China
| | - Tao Wang
- Department of Toxicology, School of Public Health, Xinxiang Medical University, Xinxiang, People's Republic of China
| | - Weidong Wu
- Department of Toxicology, School of Public Health, Xinxiang Medical University, Xinxiang, People's Republic of China
| | - Jia Cao
- Department of Toxicology, School of Public Health, Xinxiang Medical University, Xinxiang, People's Republic of China
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10
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Yoshioka W, Tohyama C. Mechanisms of Developmental Toxicity of Dioxins and Related Compounds. Int J Mol Sci 2019; 20:E617. [PMID: 30708991 PMCID: PMC6387164 DOI: 10.3390/ijms20030617] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 01/29/2019] [Accepted: 01/30/2019] [Indexed: 12/20/2022] Open
Abstract
Dioxins and related compounds induce morphological abnormalities in developing animals in an aryl hydrocarbon receptor (AhR)-dependent manner. Here we review the studies in which 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is used as a prototypical compound to elucidate the pathogenesis of morphological abnormalities. TCDD-induced cleft palate in fetal mice involves a delay in palatogenesis and dissociation of fused palate shelves. TCDD-induced hydronephrosis, once considered to be caused by the anatomical obstruction of the ureter, is now separated into TCDD-induced obstructive and non-obstructive hydronephrosis, which develops during fetal and neonatal periods, respectively. In the latter, a prostaglandin E₂ synthesis pathway and urine concentration system are involved. TCDD-induced abnormal development of prostate involves agenesis of the ventral lobe. A suggested mechanism is that AhR activation in the urogenital sinus mesenchyme by TCDD modulates the wingless-type MMTV integration site family (WNT)/β-catenin signaling cascade to interfere with budding from urogenital sinus epithelium. TCDD exposure to zebrafish embryos induces loss of epicardium progenitor cells and heart malformation. AHR2-dependent downregulation of Sox9b expression in cardiomyocytes is a suggested underlying mechanism. TCDD-induced craniofacial malformation in zebrafish is considered to result from the AHR2-dependent reduction in SRY-box 9b (SOX9b), probably partly via the noncoding RNA slincR, resulting in the underdevelopment of chondrocytes and cartilage.
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Affiliation(s)
- Wataru Yoshioka
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
| | - Chiharu Tohyama
- Laboratory of Environmental Health Sciences, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo 113-0033, Japan.
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11
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Liyun G, Xu J, Li X, Wang T, Wu W, Cao J. 2,3,7,8-Tetrachlorodibenzo-p-Dioxin and TGF-β3 Mediated-Mouse Embryonic Palatal Mesenchymal Cells. Dose Response 2018; 16:1559325818810637. [PMID: 30479586 PMCID: PMC6247497 DOI: 10.1177/1559325818810637] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Revised: 09/26/2018] [Accepted: 10/10/2018] [Indexed: 12/18/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a well-known environmental teratogenic agent for cleft palate. But transforming growth factor β3 (TGF-β3) is an essential growth factor for palatogenesis. This study is to clarify effects of TCDD and TGF-β3 in mouse embryonic palatal mesenchymal (MEPM) cells. The result showed that with increase of TCDD (0.5 nM-10 nM), the expression of TGF-β3 increased, but after 10 nM TCDD, the expression of TGF-β3 reduced. The viabilities of MEPM cells decreased in 10 nM TCDD-treated group. But the viabilities increased in 10 ng/mL TGF-β3-treated group, or the viabilities were between that of them in combination of 10 nM TCDD and 10 ng/mL TGF-β3-treated group. This phenomenon was the same as the motilities. In addition, we found that the expression of phosphorylated Smad2/3 and Smad7 was increased by 10 nM TCDD, 10 ng/mL TGF-β3, or combination of 10 nM TCDD and 10 ng/mL TGF-β3 induced, but the expression of Smad4 was decreased. These data revealed that the TGF-β/Smad signaling pathway affected TCDD and TGF-β3 in MEPM cells.
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Affiliation(s)
- Gao Liyun
- School of Public Health, Xinxiang Medical University, Xinxiang, China.,Cooperative Innovation Center of Molecular Diagnosis and Medical Inspection Technology, Xinxiang, China
| | - Jie Xu
- School of Public Health, Xinxiang Medical University, Xinxiang, China
| | - Xiao Li
- Department of Stomatology, Zhengzhou People's Hospital, Zhengzhou, Henan, China
| | - Tao Wang
- School of Basic Medical Sciences, Jiujiang University, Jiujiang, China
| | - Weidong Wu
- School of Public Health, Xinxiang Medical University, Xinxiang, China
| | - Jia Cao
- School of Public Health, Xinxiang Medical University, Xinxiang, China
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Cell Polarity and PAR Complex Likely to Be Involved in Dexamethasone-Induced Cleft Palate. J Craniofac Surg 2018; 29:260-263. [DOI: 10.1097/scs.0000000000004055] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
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Hu X, Gao JH, Liao YJ, Tang SJ, Lu F. 2,3,7,8-Tetrachlorodibenzo-p-dioxin Delays Palatal Shelf Elevation and Suppresses Wnt5a and Lymphoid Enhancing-Binding Factor 1 Signaling in Developing Palate. Cleft Palate Craniofac J 2018; 52:54-61. [PMID: 24555447 DOI: 10.1597/13-018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
OBJECTIVE 2,3,7,8-Tetrachlorodibenzo-p-dioxin contributes to cleft palate, but the cellular and molecular mechanisms responsible for the deleterious effect on the developing palate are unclear. Because Wnt signaling is associated with 2,3,7,8-tetrachlorodibenzo-p-dioxin in organ development, we wondered whether the malformation of the palate also results from altered Wnt signaling. RESULTS The 2,3,7,8-tetrachlorodibenzo-p-dioxin administration affected cell proliferation of the anteroposterior axis of the palatal shelf and delayed shelf elevation in mice. The activity of Wnt5a and lymphoid enhancing-binding factor 1 was inhibited by 2,3,7,8-tetrachlorodibenzo-p-dioxin in the developing palate. CONCLUSIONS Downregulated Wnt5a and lymphoid enhancing-binding factor 1 are associated with 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced cleft palate. Moreover, delayed shelf elevation by 2,3,7,8-tetrachlorodibenzo-p-dioxin is the crucial mechanism contributing to the high incidence of cleft palate. Our findings may help in elucidating the mechanisms of 2,3,7,8-tetrachlorodibenzo-p-dioxin-induced cleft palate.
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Yuan X, He X, Zhang X, Liu C, Wang C, Qiu L, Pu W, Fu Y. Comparative Study of Folic Acid and α-Naphthoflavone on Reducing TCDD-Induced Cleft Palate in Fetal Mice. Cleft Palate Craniofac J 2017; 54:216-222. [DOI: 10.1597/15-211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Objective To compare the effect of folic acid (FA) and α-naphthoflavone on 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-induced cleft palate in fetal mice. Design Pregnant mice were randomly divided into seven groups. The mice treated with corn oil were used as a negative control. The mice in the other six groups were given a single dose of 28 μg/kg TCDD on GD 10 by gavage. For FA treatment, TCDD-treated mice were also dosed with 5, 10, and 15 mg/kg FA on GD 10, while for α-naphthoflavone treatment, the mice received a single dose of 50 μg/kg or 5 mg/kg α-naphthoflavone on GD 10. Main Outcome Measures Fetal mice palates were imaged using light and scanning electron microscopy on GD 13.5, GD 14.5, and GD 15.5, and cleft palate were recorded on GD 17.5. The expression of guanosine diphosphate dissociation inhibitor (GDI) in fetal mice palate on GD 15.5 was examined by immunohistochemistry. Results TCDD successfully induced cleft palate. Ten mg/ml FA and 5 mg/ml α-naphthoflavone significantly reduced TCDD-induced cleft palate. FA and α-naphthoflavone partly reduced TCDD-induced cleft palate but did not affect the expression of Rho GDI. Conclusions FA and α-naphthoflavone may reduce the generation of reactive oxygen species, inhibit MEE apoptosis through anti-oxidation, and increase filopodia and MEE movement. This may result in restoration of the ultrastructure of the palatal surface to a normal state, leading to the fusion and formation of complete palate in TCDD-treated fetal mice.
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Affiliation(s)
- Xingang Yuan
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing (CSTC2009CA5002), Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Xiaomeng He
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing (CSTC2009CA5002), Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, and Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Xuan Zhang
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing (CSTC2009CA5002), Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Cuiping Liu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing (CSTC2009CA5002), Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Chen Wang
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing (CSTC2009CA5002), Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing, China
| | - Lin Qiu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing (CSTC2009CA5002), Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, and Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, China
| | - Wei Pu
- Biology Teaching and Research Section of Medical Technology College of Chengdu University of Transitional Chinese Medicine, Chengdu, China
| | - Yuexian Fu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing (CSTC2009CA5002), Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, and Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, China
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Wang C, Yuan XG, Liu CP, Zhai SN, Zhang DW, Fu YX. Preliminary research on DNA methylation changes during murine palatogenesis induced by TCDD. J Craniomaxillofac Surg 2017; 45:678-684. [PMID: 28336320 DOI: 10.1016/j.jcms.2017.02.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 12/18/2016] [Accepted: 02/06/2017] [Indexed: 11/29/2022] Open
Abstract
2,3,7,8-Tetrachlrodibenzo-p-dioxin (TCDD) has been shown to induce cleft palate through growth factor and receptor expression changes during palatogenesis. DNA methylation is an important epigenetic modification that can regulate gene expressions and may be involved in TCDD-induced cleft palate. In this study, we investigated the effects of TCDD on the global and CpG DNA methylation status and the expression levels of DNA methyltransferases (Dnmts) in palate tissue of fetal mice. Pregnant C57BL/6J mice were administered with corn oil or TCDD 28 μg/kg at gestation day 10.5(GD10.5), and sacrificed at GD13.5, 14.5, 15.5. Fetal palates were collected for molecular analysis. Global DNA methylation status was detected by Methylamp™ Global DNA Methylation Quantification Ultra Kit. The expression of DNA methyltransferases were examined by quantitative real-time PCR(q-PCR). Methylation Specific PCR (MSP) was performed to analyze CpG methylation status of Dnmts. We found that the global DNA methylation level and the expression of Dnmt3a were higher at GD13.5 in the TCDD group. The methylation level of CpG site 2 in the promoter region of Dnmt3a in the control group was higher than that of the TCDD group at GD13.5. The low CpG methylation level of Dnmt3a at GD13.5 which causes the up-expression of Dnmt3a may induce global hypermethylation in fetal palate tissue. The aberrant global methylation status at GD13.5 may be the cause of palate malformation in fetal mice induced by TCDD.
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Affiliation(s)
- Chen Wang
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Xin-Gang Yuan
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Cui-Ping Liu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Sha-Na Zhai
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Ding-Wen Zhang
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China
| | - Yue-Xian Fu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Department of Burns and Plastic Surgery, Children's Hospital of Chongqing Medical University, Chongqing, 400014, China.
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Effect of TCDD on the fate of epithelial cells isolated from human fetal palatal shelves (hFPECs). Toxicol Appl Pharmacol 2016; 305:186-193. [DOI: 10.1016/j.taap.2016.06.016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Revised: 06/09/2016] [Accepted: 06/10/2016] [Indexed: 12/21/2022]
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17
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Yuan X, Qiu L, Pu Y, Liu C, Zhang X, Wang C, Pu W, Fu Y. Histone acetylation is involved in TCDD‑induced cleft palate formation in fetal mice. Mol Med Rep 2016; 14:1139-45. [PMID: 27279340 PMCID: PMC4940082 DOI: 10.3892/mmr.2016.5348] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Accepted: 03/21/2016] [Indexed: 01/21/2023] Open
Abstract
The aim of the present was to evaluate the effects of DNA methylation and histone acetylation on 2,3,7,8-tetrachlo-rodibenzo-p-dioxin (TCDD)-induced cleft palate in fetal mice. Pregnant mice (n=10) were randomly divided into two groups: i) TCDD group, mice were treated with 28 µg/kg TCDD on gestation day (GD) 10 by oral gavage; ii) control group, mice were treated with an equal volume of corn oil. On GD 16.5, the fetal mice were evaluated for the presence of a cleft palate. An additional 36 pregnant mice were divided into the control and TCDD groups, and palate samples were collected on GD 13.5, GD 14.5 and GD 15.5, respectively. Transforming growth factor-β3 (TGF-β3) mRNA expression, TGF-β3 promoter methylation, histone acetyltransferase (HAT) activity and histone H3 (H3) acetylation in the palates were evaluated in the two groups. The incidence of a cleft palate in the TCDD group was 93.55%, and no cases of cleft palate were identified in the control group. On GD 13.5 and GD 14.5, TGF-β3 mRNA expression, HAT activity and acetylated H3 levels were significantly increased in the TCDD group compared with the control. Methylated bands were not observed in the TCDD or control groups. In conclusion, at the critical period of palate fusion (GD 13.5–14.5), TCDD significantly increased TGF-β3 gene expression, HAT activity and H3 acetylation. Therefore, histone acetylation may be involved in TCDD-induced cleft palate formation in fetal mice.
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Affiliation(s)
- Xingang Yuan
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing 400014, P.R. China
| | - Lin Qiu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing 400014, P.R. China
| | - Yalan Pu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing 400014, P.R. China
| | - Cuiping Liu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing 400014, P.R. China
| | - Xuan Zhang
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing 400014, P.R. China
| | - Chen Wang
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing 400014, P.R. China
| | - Wei Pu
- Biology Teaching and Research Section of Medical Technology College, Chengdu University of Transitional Chinese Medicine, Chengdu, Sichuan 611137, P.R. China
| | - Yuexian Fu
- Ministry of Education Key Laboratory of Child Development and Disorders, Key Laboratory of Pediatrics in Chongqing, Chongqing International Science and Technology Cooperation Center for Child Development and Disorders, Chongqing 400014, P.R. China
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Gao Z, Bu Y, Liu X, Wang X, Zhang G, Wang E, Ding S, Liu Y, Shi R, Li Q, Fu J, Yu Z. TCDD promoted EMT of hFPECs via AhR, which involved the activation of EGFR/ERK signaling. Toxicol Appl Pharmacol 2016; 298:48-55. [PMID: 26971374 DOI: 10.1016/j.taap.2016.03.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 02/15/2016] [Accepted: 03/08/2016] [Indexed: 02/01/2023]
Abstract
One critical step of second palatal fusion is the newly formed medial epithelia seam (MES) disintegration, which involves apoptosis, epithelial to mesenchymal transition (EMT), and cell migration. Although the environmental toxicant 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) produces cleft palate at high rates, little is known about the effects of TCDD exposure on the fate of palatal epithelial cells. By using primary epithelial cells isolated from human fetal palatal shelves (hFPECs), we show that TCDD increased cell proliferation and EMT, as demonstrated by increased the epithelial markers (E-cadherin and cytokeratin14) and enhanced the mesenchymal markers (vimentin and fibronectin), but had no effect on cell migration and apoptosis. TCDD exposure led to a dose-dependent increase in Slug protein expression. Coimmunoprecipitation revealed that TCDD promoted AhR to form a protein complex with Slug. ChIP assay confirmed that TCDD exposure recruited AhR to the xenobiotic responsive element of Slug promoter. Knockdown of AhR by siRNA remarkably weakened TCDD-induced binding of AhR to the XRE promoter of slug, thereby suppressed TCDD-induced vimentin. Further experiment showed that TCDD stimulated EGFR phosphorylation did not influence the TGFβ3/Smad signaling; whereas TCDD increased phosphorylation of ERK1/2 and p38 with no effect on activation of JNK. By using varieties of inhibitors, we confirmed that TCDD promoted proliferation and EMT of hFPECs via activation of EGFR/ERK pathway. These data make a novel contribution to the molecular mechanism of cleft palate by TCDD.
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Affiliation(s)
- Zhan Gao
- School of Public Health, Xinxiang Medical University, 453003, China; The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Yongjun Bu
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Xiaozhuan Liu
- Medical College, Henan University of Science & Technology, 471023, China
| | - Xugang Wang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Guofu Zhang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Erhui Wang
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Shibin Ding
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Yongfeng Liu
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Ruling Shi
- School of Public Health, Xinxiang Medical University, 453003, China
| | - Qiaoyun Li
- The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Jianhong Fu
- The Fifth Affiliated Hospital, Zhengzhou University, 450052, China
| | - Zengli Yu
- School of Public Health, Xinxiang Medical University, 453003, China; School of Public Health, Zhengzhou University, 450001, China.
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Burns FR, Peterson RE, Heideman W. Dioxin disrupts cranial cartilage and dermal bone development in zebrafish larvae. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2015; 164:52-60. [PMID: 25914093 PMCID: PMC4470709 DOI: 10.1016/j.aquatox.2015.04.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Revised: 04/02/2015] [Accepted: 04/03/2015] [Indexed: 05/07/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD or dioxin) disrupts craniofacial development in zebrafish larvae. However, the cellular changes responsible for the decreased jaw size remain poorly understood. We show that smaller jaw size is due to a decrease in both the size and number of chondrocytes in the developing craniofacial cartilages. TCDD was found to decrease ossification of osteoblasts in the perichondrium of craniofacial cartilages. We also discovered that TCDD caused clefting of the parasphenoid, an effect with similarity to TCDD-induced cleft palate in mice. Thus, dermal and perichondrial bone development of the craniofacial skeleton are clearly disrupted by TCDD exposure in the zebrafish larvae. This dysmorphic response of the zebrafish craniofacial skeleton after exposure to TCDD is consistent with findings demonstrating disruption of axial bone development in medaka and repression of sox9b in zebrafish.
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Affiliation(s)
- Felipe R Burns
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53705, USA.
| | - Richard E Peterson
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53705, USA; School of Pharmacy, University of Wisconsin Madison, WI 53705, USA
| | - Warren Heideman
- Molecular and Environmental Toxicology Center, University of Wisconsin, Madison, WI 53705, USA; School of Pharmacy, University of Wisconsin Madison, WI 53705, USA
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Zhao SF, Chai MZ, Wu M, He YH, Meng T, Shi B. Effect of vitamin B12 on cleft palate induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin and dexamethasone in mice. J Zhejiang Univ Sci B 2014; 15:289-94. [PMID: 24599693 DOI: 10.1631/jzus.b1300083] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The purpose of this study was to investigate the effect of vitamin B12 on palatal development by co-administration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and dexamethasone (DEX). We examined the morphological and histological features of the palatal shelf and expression levels of key signaling molecules (transforming growth factor-β3 (TGF-β3) and TGF-β type I receptor (activin receptor-like kinase 5, ALK5)) during palatogenesis among a control group (Group A), TCDD+DEX exposed group (Group B), and TCDD+DEX+vitamin B12 exposed group (Group C). While we failed to find that vitamin B12 decreased the incidence of cleft palate induced by TCDD+DEX treatment, the expression levels of key signaling molecules (TGF-β3 and ALK5) during palatogenesis were significantly modulated. In TCDD+DEX exposed and TCDD+DEX+vitamin B12 exposed groups, palatal shelves could not contact in the midline due to their small sizes. Our results suggest that vitamin B12 may inhibit the expression of some cleft palate inducers such as TGF-β3 and ALK5 in DEX+TCDD exposed mice, which may be beneficial against palatogenesis to some degree, even though we were unable to observe a protective role of vitamin B12 in morphological and histological alterations of palatal shelves induced by DEX and TCDD.
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Affiliation(s)
- Shu-Fan Zhao
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; Department of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu 610041, China; Department of Biochemistry & Molecular Biology, University of North Dakota School of Medicine & Health Sciences, Grand Forks, ND 58203, USA
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Wu C, Endo M, Yang BH, Radecki MA, Davis PF, Zoltick PW, Spivak RM, Flake AW, Kirschner RE, Nah HD. Intra-amniotic transient transduction of the periderm with a viral vector encoding TGFβ3 prevents cleft palate in Tgfβ3(-/-) mouse embryos. Mol Ther 2012; 21:8-17. [PMID: 23089732 DOI: 10.1038/mt.2012.135] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cleft palate is a developmental defect resulting from the failure of embryonic palatal shelves to fuse with each other at a critical time. Immediately before and during palatal fusion (E13-E15 in mice), transforming growth factor β3 (TGFβ3) is expressed in the palatal shelf medial edge epithelium (MEE) and plays a pivotal role in palatal fusion. Using Tgfβ3(-/-) mice, which display complete penetrance of the cleft palate phenotype, we tested the hypothesis that intra-amniotic gene transfer could be used to prevent cleft palate formation by restoring palatal midline epithelial function. An adenoviral vector encoding Tgfβ3 was microinjected into the amniotic sacs of mouse embryos at successive developmental stages. Transduced Tgfβ3(-/-) fetuses showed efficient recovery of palatal fusion with mesenchymal confluence following injection at E12.5 (100%), E13.5 (100%), E14.5 (82%), and E15.5 (75%). Viral vectors injected into the amniotic sac transduced the most superficial and transient peridermal cell layer but not underlying basal epithelial cells. TGFβ3 transduction of the peridermdal cell layer was sufficient to induce adhesion, fusion, and disappearance of the palatal shelf MEE in a cell nonautonomous manner. We propose that intra-amniotic gene transfer approaches have therapeutic potential to prevent cleft palate in utero, especially those resulting from palatal midline epithelial dysfunction.
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Affiliation(s)
- Chadwick Wu
- Division of Plastic and Reconstructive Surgery, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania 19104, USA
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Yuan X, Liu L, Pu Y, Zhang X, He X, Fu Y. 2,3,7,8-Tetrachlorodibenzo-p-dioxin induces a proteomic pattern that defines cleft palate formation in mice. Food Chem Toxicol 2012; 50:2270-4. [DOI: 10.1016/j.fct.2012.04.032] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Revised: 04/17/2012] [Accepted: 04/19/2012] [Indexed: 11/15/2022]
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Abbott BD. The etiology of cleft palate: a 50-year search for mechanistic and molecular understanding. ACTA ACUST UNITED AC 2010; 89:266-74. [PMID: 20602452 DOI: 10.1002/bdrb.20252] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Dates of special, historical significance, such as the 50th anniversary of the founding of the Teratology Society, prompt a desire to pause and look back and contemplate where we began, how far we have come, and consider the future for our scientific endeavors. The study of the etiology of cleft palate extends many years into the past and was a subject of interest to many of the founding members of the Teratology Society. This research area was intensively pursued and spawned a vast portfolio of published research. This article will look back at the state of the science around the time of the founding of the Teratology Society, in the 1950s and 1960s, and track the emergence and pursuit of an interest in an etiology for cleft palate involving failure of palatal fusion. Studies of medial epithelial cell fate and induction of cleft palate by interference with adhesion or fusion span the period from the 1960s to the present time. Teratology Society members have been and continue to be key players in cleft palate research. In this retrospective article, seminal research published by Teratology Society members will serve as a platform to launch the discussion of the emergence of our current understanding of medial epithelial cell differentiation and fate and the potential for these processes to be targets of teratogenic action.
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Affiliation(s)
- Barbara D Abbott
- Developmental Biology Branch, Toxicity Assessment Division, National Health and Environmental Effects Research Laboratory, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
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Li CH, Bing Shi, Wei He, Tian Meng. Is it possible to antagonize 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin- induced cleft palate by prenatal administration of folic acid? An experimental study. Toxicol Ind Health 2010; 26:281-6. [PMID: 20305052 DOI: 10.1177/0748233710364964] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) can cause a high percentage of cleft palate in fetuses when administered during organogenesis in certain strains of mice including C57BL/6J. In this study, folic acid (FA) was tested for antiteratogenic effects on TCDD-induced cleft palate in fetal mice. The pregnant C57BL/6J mice were dosed with 24 µg TCDD/kg and/or 5 mg, 10 mg, 20 mg, 40 mg FA/kg body weight on gestation day (GD) 10. The control group mice received 50 mL sesame oil/kg body weight on GD10. The mice were sacrificed on GD12.5, GD13.5, GD14.5, GD15.5, and GD16.5. The harvested embryos were examined to detect the incidence of cleft palate and the developing palatal shelves on different phases were investigated morphologically and histologically among different groups. Total frequency of clefts was 55.56% in TCDD group and 17.50% (5 mg), 42.85% (10 mg), 42.10% (20 mg), 28.26% (40 mg) in TCDD + FA groups. FA (5 mg) reduced the incidence of the cleft palate from 55.56% to 17.50% (p = 0.005). There were no significant differences between the TCDD group and 10 mg, 20 mg, 40 mg TCDD + FA groups. Based on the these results, the present study suggests that FA can reduce the incidence of 2,3,7,8-TCDD-indued cleft palate in mice.
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Affiliation(s)
- Cheng-hao Li
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, People's Republic of China, Department of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Bing Shi
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, People's Republic of China, Department of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Wei He
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, People's Republic of China, Department of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
| | - Tian Meng
- State Key Laboratory of Oral Diseases, West China College of Stomatology, Sichuan University, Chengdu, People's Republic of China, Department of Cleft Lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Chengdu, People's Republic of China
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25
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Experimental study on protection of vitamin B6on TCDD-induced palatal cleft formation in the mice. ACTA ACUST UNITED AC 2009; 86:357-61. [DOI: 10.1002/bdrb.20203] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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26
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Gan LQ, Fu YX, Liu X, Qiu L, Wu SD, Tian XF, Liu Y, Wei GH. Transforming growth factor-β3 expression up-regulates on cleft palates induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin in mice. Toxicol Ind Health 2009; 25:473-8. [PMID: 19783572 DOI: 10.1177/0748233709345940] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) has been shown to induce cleft palate, in which the molecular etiology of the defect is poorly characterized. Recently, transforming growth factor-β3 (TGF-β3) has been indicated to play an essential role in the development of palatal shelves. In this developmental toxicity study, we investigated the effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the expression of TGF-β3 in fetal mice. Pregnant C57BL/6 mice were exposed to corn oil or TCDD (32 μg/kg/day 64 μg/kg/day, per os) at embryonic day 10 (ED10), a drastic inhibition of palatal shelves was induced. By using RT-PCR (reverse transcription-polymerase chain reaction) and Western blot, the expressions of TGF-β3 was investigated. We found that the expression of TGF-β3 was gradually up-regulated in TCDD-treated group. These results suggest that cleft palate can be induced by TCDD exposure, the modification of TGF-β3 is related to its pathogenesis.
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Affiliation(s)
- Li-qiang Gan
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
| | - Yue-xian Fu
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
| | - Xing Liu
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
| | - Lin Qiu
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
| | - Sheng-de Wu
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
| | - Xiao-fei Tian
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
| | - Yan Liu
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
| | - Guang-hui Wei
- Department of Pediatric Surgery, Chongqing Children’s Hospital, Chongqing Medical University, Chongqing, China
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27
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Stevens EA, Mezrich JD, Bradfield CA. The aryl hydrocarbon receptor: a perspective on potential roles in the immune system. Immunology 2009; 127:299-311. [PMID: 19538249 DOI: 10.1111/j.1365-2567.2009.03054.x] [Citation(s) in RCA: 292] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a protein best known for its role in mediating toxicity. Over 30 years of research has uncovered additional roles for the AHR in xenobiotic metabolism and normal vascular development. Activation of the AHR has long been known to cause immunotoxicity, including thymic involution. Recent data suggesting a role for the AHR in regulatory T-cell (Treg) and T-helper 17 (Th17) cell development have only added to the excitement about this biology. In this review, we will attempt to illustrate what is currently known about AHR biology in the hope that data from fields as diverse as evolutionary biology and pharmacology will help elucidate the mechanism by which AHR modifies immune responses. We also will discuss the complexities of AHR pharmacology and genetics that may influence future studies of AHR in the immune system.
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Affiliation(s)
- Emily A Stevens
- University of Wisconsin School of Medicine and Public Health, Madison, WI 53706-1599, USA
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Ma C, Marlowe JL, Puga A. The aryl hydrocarbon receptor at the crossroads of multiple signaling pathways. EXS 2009; 99:231-57. [PMID: 19157064 DOI: 10.1007/978-3-7643-8336-7_9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The aryl hydrocarbon receptor (AHR) has long been recognized as a ligand-activated transcription factor responsible for the induction of drug-metabolizing enzymes. Its role in the combinatorial matrix of cell functions was established long before the first report of an AHR cDNA sequence was published. It is only recently that other functions of this protein have begun to be recognized, and it is now clear that the AHR also functions in pathways outside of its well-characterized role in xenobiotic enzyme induction. Perturbation of these pathways by xenobiotic ligands may ultimately explain much of the toxicity of these compounds. This chapter focuses on the interactions of the AHR in pathways critical to cell cycle regulation, mitogen-activated protein kinase cascades, differentiation and apoptosis. Ultimately, the effect of a particular AHR ligand on the biology of the organism will depend on the milieu of critical pathways and proteins expressed in specific cells and tissues with which the AHR itself interacts.
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Affiliation(s)
- Ci Ma
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati College of Medicine, Cincinnati, OH 45220, USA.
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Mathew LK, Sengupta SS, Ladu J, Andreasen EA, Tanguay RL. Crosstalk between AHR and Wnt signaling through R-Spondin1 impairs tissue regeneration in zebrafish. FASEB J 2008; 22:3087-96. [PMID: 18495758 DOI: 10.1096/fj.08-109009] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Exposure to dioxins, including 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), causes a wide array of toxicities in vertebrates, which are mostly considered to be mediated through the inappropriate activation of the aryl hydrocarbon receptor (AHR) signaling pathway. Although transcriptional regulation by AHR is widely studied, the molecular mechanisms responsible for the adverse outcomes after AHR activation are largely unknown. To identify the important downstream events of AHR activation, we employed the zebrafish caudal fin regeneration model, where AHR activation blocks the regenerative process. Comparative toxicogenomic analysis revealed that both adult and larval fins respond to TCDD during regeneration with misexpression of Wnt signaling pathway members and Wnt target genes. R-Spondin1, a novel ligand for the Wnt coreceptor, was highly induced, and we hypothesized that misexpression of R-Spondin1 is necessary for AHR activation to block regeneration. Partial antisense repression of R-Spondin1 reversed the inhibitory effect of TCDD, and tissue regeneration was restored. This finding demonstrates that inhibition of regeneration by TCDD is mediated by misinduction of R-Spondin1. Because R-Spondin1 signals through the Wnt coreceptor LRP6, we further demonstrated that the TCDD-mediated block in regeneration is also LRP6 dependent. Collectively, these results indicate that inappropriate regulation of R-Spondin/LRP6 is absolutely required for TCDD to inhibit fin regeneration.
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Affiliation(s)
- Lijoy K Mathew
- Oregon State University, Environmental Health Sciences Center, Department of Environmental and Molecular Toxicology, Corvallis, Oregon 97331-7301, USA
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Shi M, Wehby GL, Murray JC. Review on genetic variants and maternal smoking in the etiology of oral clefts and other birth defects. BIRTH DEFECTS RESEARCH. PART C, EMBRYO TODAY : REVIEWS 2008; 84:16-29. [PMID: 18383123 PMCID: PMC2570345 DOI: 10.1002/bdrc.20117] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
A spectrum of adverse pregnancy outcomes, including preterm birth, low birth weight, and birth defects has been linked with maternal smoking during pregnancy. This article includes a review of studies investigating interactions between genetic variants and maternal smoking in contributing to birth defects using oral clefting as a model birth defect. The primary gene-smoking studies for other major birth defects are also summarized. Gene-environment interaction studies for birth defects are still at an early stage with several mixed results, but evolving research findings have begun to document clinically and developmentally important interactions. As samples and data become increasingly available, more effort is needed in designing innovative analytical methods to study gene-environment interactions.
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Affiliation(s)
- Min Shi
- Biostatistics Branch, NIEHS, NIH, DHHS, Research Triangle Park, North Carolina, USA
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31
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Chang X, Fan Y, Karyala S, Schwemberger S, Tomlinson CR, Sartor MA, Puga A. Ligand-independent regulation of transforming growth factor beta1 expression and cell cycle progression by the aryl hydrocarbon receptor. Mol Cell Biol 2007; 27:6127-39. [PMID: 17606626 PMCID: PMC1952156 DOI: 10.1128/mcb.00323-07] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor that mediates the toxic effects of its xenobiotic ligands and acts as an environmental checkpoint during the cell cycle. We expressed stably integrated, Tet-Off-regulated AHR variants in fibroblasts from AHR-null mice to further investigate the AHR role in cell cycle regulation. Ahr+/+ fibroblasts proliferated significantly faster than Ahr-/- fibroblasts did, and exposure to a prototypical AHR ligand or deletion of the ligand-binding domain did not change their proliferation rates, indicating that the AHR function in cell cycle was ligand independent. Growth-promoting genes, such as cyclin and cyclin-dependent kinase genes, were significantly down-regulated in Ahr-/- cells, whereas growth-arresting genes, such as the transforming growth factor beta1 (TGF-beta1) gene, extracellular matrix (ECM)-related genes, and cyclin-dependent kinase inhibitor genes, were up-regulated. Ahr-/- fibroblasts secreted significantly more TGF-beta1 into the culture medium than Ahr+/+ fibroblasts did, and Ahr-/- showed increased levels of activated Smad4 and TGF-beta1 mRNA. Inhibition of TGF-beta1 signaling by overexpression of Smad7 reversed the proliferative and gene expression phenotype of Ahr-/- fibroblasts. Changes in TGF-beta1 mRNA accumulation were due to stabilization resulting from decreased activity of TTP, the tristetraprolin RNA-binding protein responsible for mRNA destabilization through AU-rich motifs. These results show that the Ah receptor possesses interconnected intrinsic cellular functions, such as ECM formation, cell cycle control, and TGF-beta1 regulation, that are independent of activation by either exogenous or endogenous ligands and that may play a crucial role during tumorigenesis.
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Affiliation(s)
- Xiaoqing Chang
- Department of Environmental Health, University of Cincinnati Medical Center, and Shriners Hospital for Children, Cincinnati, OH 45267-0056, USA
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32
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McMillan BJ, Bradfield CA. The aryl hydrocarbon receptor sans xenobiotics: endogenous function in genetic model systems. Mol Pharmacol 2007; 72:487-98. [PMID: 17535977 DOI: 10.1124/mol.107.037259] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
For more than 30 years, the aryl hydrocarbon receptor [Ah receptor (AHR)] has been extensively scrutinized as the cellular receptor for numerous environmental contaminants, including polychlorinated dioxins, dibenzofurans, and biphenyls. Recent evidence argues that this description is incomplete and perhaps myopic. Ah receptor orthologs have been demonstrated to mediate diverse endogenous functions in our close vertebrate relatives as well as our distant invertebrate ancestors. Moreover, these endogenous functions suggest that xenobiotic toxicity may be best understood in the context of intrinsic AHR physiology. In this literature review, we survey the emerging picture of endogenous AHR biology from work in the vertebrate and invertebrate model systems Mus musculus, Caenorhabditis elegans, and Drosophila melanogaster.
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Affiliation(s)
- Brian J McMillan
- McArdle Laboratory for Cancer Research, University of Wisconsin Shool of Medicine and Public Health, Madison, Wisconsin, USA
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33
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Kovacic P, Pozos RS. Cell signaling (mechanism and reproductive toxicity): redox chains, radicals, electrons, relays, conduit, electrochemistry, and other medical implications. ACTA ACUST UNITED AC 2007; 78:333-44. [PMID: 17315245 DOI: 10.1002/bdrc.20083] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
This article deals with a novel, simple, integrated approach to cell signaling involving basic biochemical principles, and their relationship to reproductive toxicity. Initially, an overview of the biological aspects is presented. According to the hypothetical approach, cell signaling entails interaction of redox chains, involving initiation, propagation, and termination. The messengers are mainly radicals and electrons that are generated during electron transfer (ET) and hydrogen atom abstraction reactions. Termination and initiation processes in the chain occur at relay sites occupied by redox functionalities, including quinones, metal complexes, and imines, as well as redox amino acids. Conduits for the messengers, comprising species with nonbonding electrons, are omnipresent. Details are provided for the various electron transfer processes. In relation to the varying rates of cell communication, rationale is based on electrons and size of radicals. Another fit is similarly seen in inspection of endogenous precursors of reactive oxygen species (ROS); namely, proteins bearing redox moieties, lipid oxidation products, and carbohydrate radicals. A hypothesis is advanced in which electromagnetic fields associated with mobile radicals and electrons play a role. Although radicals have previously been investigated as messengers, the area occupies a minor part of the research, and it has not attracted broad consensus as an important component. For the first time, an integrated framework is presented composed of radicals, electrons, relays, conduits, and electrical fields. The approach is in keeping with the vast majority of experimental observations. Cell signaling also plays an important role in reproductive toxicity. The main classes that cause birth defects, including ROS, radiation, metal compounds, medicinals, abused drugs, and miscellaneous substances, are known to participate in the signaling process. A unifying basis exists, in that both signaling and reproductive toxicity are characterized by the electron transfer-reactive oxygen species-oxidative stress (ET-ROS-OS) scheme. This article also incorporates representative examples of the extensive investigations dealing with various medical implications. There is considerable literature pointing to a role for cell communication in a wide variety of illnesses.
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Affiliation(s)
- Peter Kovacic
- Department of Chemistry, San Diego State University, San Diego, California 92182-1030, USA.
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34
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Bock KW, Köhle C. Ah receptor: Dioxin-mediated toxic responses as hints to deregulated physiologic functions. Biochem Pharmacol 2006; 72:393-404. [PMID: 16545780 DOI: 10.1016/j.bcp.2006.01.017] [Citation(s) in RCA: 264] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2005] [Revised: 01/23/2006] [Accepted: 01/24/2006] [Indexed: 01/28/2023]
Abstract
The aryl hydrocarbon receptor (AhR) is a ligand-activated transcription factor and member of the bHLH/PAS (basic Helix-Loop-Helix/Per-Arnt-Sim) family of chemosensors and developmental regulators. It represents a multifunctional molecular switch regulating endo- and xenobiotic metabolism as well as cell proliferation and differentiation. Physiologic functions of the AhR are beginning to be understood, including functions in vascular development, and in detoxification of endo- and xenobiotics. The AhR is also recognized as the culprit for most toxic responses observed after exposure to dioxins and related compounds such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The non-metabolizable AhR agonist TCDD has to be distinguished from the myriad of metabolizable agonists present as dietary contaminants and plant constituents as well as endogenous toxins. The hypothesis is emerging that the diverse tissue-specific, TCDD-mediated toxicities are due to sustained and inappropriate AhR activation leading to deregulated physiologic functions. In support of this hypothesis recent observations in the context of some TCDD-mediated toxic responses are discussed, such as chloracne, cleft palate, thymus involution and in particular carcinogenesis. Major open questions are addressed, such as ligand-independent AhR activation by phosphorylation and the large differences in species-dependent susceptibility to toxic responses. Though important issues remain unresolved, the commentary is intended to stimulate efforts to understand dioxin-mediated toxic responses with emphasis on carcinogenesis in comparison with AhR-mediated physiologic functions.
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Affiliation(s)
- Karl Walter Bock
- Department of Toxicology, Institute of Pharmacology and Toxicology, University of Tübingen, Tübingen, Germany.
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35
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Harper PA, Riddick DS, Okey AB. Regulating the regulator: Factors that control levels and activity of the aryl hydrocarbon receptor. Biochem Pharmacol 2006; 72:267-79. [PMID: 16488401 DOI: 10.1016/j.bcp.2006.01.007] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2005] [Revised: 01/12/2006] [Accepted: 01/12/2006] [Indexed: 11/17/2022]
Abstract
The aryl hydrocarbon receptor (AHR) participates in a wide range of critical cellular events in response to endogenous signals or xenobiotic chemicals. Hence, it is important that AHR levels and activity themselves be well controlled in target tissues. The AHR is essentially ubiquitous in its distribution in mammalian tissues. However, levels of the receptor vary widely across different tissues and among different cell types. AHR levels and activity are modulated by exposure to the receptor's own ligands and are influenced by other xenobiotic chemicals. Many different factors impinge on AHR levels and AHR activity. These factors may alter responsiveness of downstream pathways, thereby affecting normal physiologic functions as well as responses to toxic environmental chemicals such as dioxins. Our commentary appraises the current literature on factors that regulate AHR levels/activity and attempts to identify fruitful strategies towards discovery of key pathways by which AHR levels are modulated in response to endogenous signals and in response to xenobiotic chemicals. An extraordinarily large number of agents alter the level or activity of the AHR. We have not yet entered an age of enlightenment sufficient to achieve true understanding of the interplay of mechanisms that regulate AHR expression in space and in time.
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Affiliation(s)
- Patricia A Harper
- Program in Developmental Biology, The Hospital for Sick Children, Toronto, Ont., Canada
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Thomae TL, Stevens EA, Liss AL, Drinkwater NR, Bradfield CA. The Teratogenic Sensitivity to 2,3,7,8-Tetrachlorodibenzo-p-dioxin Is Modified by a Locus on Mouse Chromosome 3. Mol Pharmacol 2005; 69:770-5. [PMID: 16354765 DOI: 10.1124/mol.105.019760] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In an effort to understand how genetics can influence individual sensitivity to environmentally induced disease, we performed a linkage analysis to identify murine loci in addition to the Ahr locus that influence the incidence of cleft palate and hydronephrosis in developing mice exposed to the pollutant 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). Administration of 64 microg/kg dioxin to C57BL/6J (B6) dams at embryonic day 9 (E9) led to palatal clefting and hydronephrosis in nearly 100% of embryos by E17. In contrast, similar exposure of CBA/J (CBA) dams led to cleft palate in only 8% and hydronephrosis in 69% of embryos. To determine the genetic basis for this strain-dependent sensitivity, linkage analyses on the progeny of a B6CBAF1 intercross and a CBAxB6CBAF1 backcross were performed. The incidences of cleft palate and hydronephrosis were assessed and genomic DNA from embryos was analyzed at informative simple sequence length polymorphism (SSLP) markers. One locus segregating with dioxin-induced cleft palate was identified (p < 0.01) and designated as chemically mediated teratogenesis number 1 (Cmt1). The Cmt1 locus is located on chromosome 3.
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Affiliation(s)
- Tami L Thomae
- McArdle Laboratory for Cancer Research, 1400 University Avenue, Madison, WI 53706-1599, USA
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Thackaberry EA, Jiang Z, Johnson CD, Ramos KS, Walker MK. Toxicogenomic profile of 2,3,7,8-tetrachlorodibenzo-p-dioxin in the murine fetal heart: modulation of cell cycle and extracellular matrix genes. Toxicol Sci 2005; 88:231-41. [PMID: 16120747 DOI: 10.1093/toxsci/kfi301] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and similar environmental contaminants have been demonstrated to be potent cardiovascular teratogens in developing piscine and avian species. In the present study, we investigated the effects of TCDD on gene expression during murine cardiovascular development. C57Bl6N pregnant mice were dosed with 1.5, 3.0, or 6.0 microg TCDD/kg on gestational day (GD) 14.5, and microarray analysis was used to characterize the global changes in fetal cardiac gene expression on GD 17.5. TCDD significantly altered expression of a number of genes involved in xenobiotic metabolism, cardiac homeostasis, extracellular matrix production/remodeling, and cell cycle regulation. Interestingly, while the AhR-responsive genes Cyp1A1, Cyp1B1, Ugt1a6, and Ahrr, were all induced by TCDD in the fetal murine heart, other AhR-responsive genes, Cyp1a2, Nqo1, and Gsta1, were not. Quantitative real-time polymerase chain reactions confirmed the changes in expression of several G1/S-type cyclins and extracellular matrix-related genes. These results demonstrate the global changes in cardiac gene expression that result from TCDD exposure of the fetal murine heart and implicate genes involved in cell cycle and extracellular matrix regulation in TCDD-induced cardiac teratogenicity and functional deficits.
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Affiliation(s)
- E A Thackaberry
- College of Pharmacy, University of New Mexico Health Sciences Center, Albuquerque, New Mexico 87131, USA
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