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Association of xenobiotic-metabolizing genes polymorphisms with cervical cancer risk in the Tunisian population. Mol Biol Rep 2023; 50:949-959. [PMID: 36376536 DOI: 10.1007/s11033-022-07945-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 09/13/2022] [Indexed: 11/15/2022]
Abstract
BACKGROUND Host genetic characteristics and environmental factors interactions may play a crucial role in cervical carcinogenesis. We investigated the impact of functional genetic variants of four xenobiotic-metabolizing genes (AhR, CYP1A1, GSTM1, and GSTT1) on cervical cancer development in Tunisian women. METHODS The AhR gene polymorphism was analyzed using the tetra-primer ARMS-PCR, whereas the CYP1A1 polymorphism genotypes were identified by PCR-RFLP. A multiplex ligation-dependent polymerase chain reaction approach was applied for the analysis of GSTM1 and GSTT1 polymorphisms. RESULTS The homozygous A/A genotype of the AhR gene (rs2066853) and the heterozygous T/C genotype of the CYP1A1 SNP (CYP1A1-MspI) appeared to be associated with an increased risk of cervical tumorigenesis (ORa = 2.81; ORa = 5.52, respectively). Furthermore, a significantly increased risk of cervical cancer was associated with the GSTT1 null genotype (ORa = 2.65). However, the null GSTM1 genotype showed any significant association with the risk of cervical cancer compared to the wild genotype (ORa = 1.18; p = 0.784). Considering the combined effect, we noted a significantly higher association with cancer risk for individuals with at least two high-risk genotypes of CYP1A1/GSTT1 (ORa = 4.2), individuals with at least two high-risk genotypes of CYP1A1/GSTT1/AhR (ORa = 11.3) and individuals with at least two high-risk genotypes of CYP1A1/GSTM1/GSTT1/AhR exploitation low-risk genotype as a reference. CONCLUSION This study indicated that the single-gene contribution and the combined effect of xenobiotic-metabolizing gene polymorphisms (AhR, CYP1A1-MspI, GSTM1, and GSTT1) may have a considerable association with increased cervical cancer risk.
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Edamitsu T, Taguchi K, Okuyama R, Yamamoto M. AHR and NRF2 in Skin Homeostasis and Atopic Dermatitis. Antioxidants (Basel) 2022; 11:antiox11020227. [PMID: 35204110 PMCID: PMC8868544 DOI: 10.3390/antiox11020227] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2021] [Revised: 01/20/2022] [Accepted: 01/22/2022] [Indexed: 01/27/2023] Open
Abstract
Skin is constantly exposed to environmental insults, including toxic chemicals and oxidative stress. These insults often provoke perturbation of epidermal homeostasis and lead to characteristic skin diseases. AHR (aryl hydrocarbon receptor) and NRF2 (nuclear factor erythroid 2-related factor 2) are transcription factors that induce a battery of cytoprotective genes encoding detoxication and antioxidant enzymes in response to environmental insults. In addition to their basic functions as key regulators of xenobiotic and oxidant detoxification, recent investigations revealed that AHR and NRF2 also play critical roles in the maintenance of skin homeostasis. In fact, specific disruption of AHR function in the skin has been found to be associated with the pathogenesis of various skin diseases, most prevalently atopic dermatitis (AD). In this review, current knowledge on the roles that AHR and NRF2 play in epidermal homeostasis was summarized. Functional annotations of genetic variants, both regulatory and nonsynonymous SNPs, identified in the AHR and NRF2 loci in the human genome were also summarized. Finally, the possibility that AHR and NRF2 serve as therapeutic targets of AD was assessed.
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Affiliation(s)
- Tomohiro Edamitsu
- Department of Medical Biochemistry, Graduate School of Medicine, Tohoku University, Sendai 980-8575, Japan; (T.E.); (K.T.)
- Department of Dermatology, Shinshu University Graduate School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan;
| | - Keiko Taguchi
- Department of Medical Biochemistry, Graduate School of Medicine, Tohoku University, Sendai 980-8575, Japan; (T.E.); (K.T.)
- Department of Medical Biochemistry, Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8573, Japan
- Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, Sendai 980-8573, Japan
| | - Ryuhei Okuyama
- Department of Dermatology, Shinshu University Graduate School of Medicine, 3-1-1 Asahi, Matsumoto 390-8621, Japan;
| | - Masayuki Yamamoto
- Department of Medical Biochemistry, Graduate School of Medicine, Tohoku University, Sendai 980-8575, Japan; (T.E.); (K.T.)
- Department of Medical Biochemistry, Tohoku Medical Megabank Organization, Tohoku University, Sendai 980-8573, Japan
- Advanced Research Center for Innovations in Next-Generation Medicine (INGEM), Tohoku University, Sendai 980-8573, Japan
- Correspondence: ; Tel.: +81-22-717-8084
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Sahebnasagh A, Hashemi J, Khoshi A, Saghafi F, Avan R, Faramarzi F, Azimi S, Habtemariam S, Sureda A, Khayatkashani M, Safdari M, Rezai Ghaleno H, Soltani H, Khayat Kashani HR. Aromatic hydrocarbon receptors in mitochondrial biogenesis and function. Mitochondrion 2021; 61:85-101. [PMID: 34600156 DOI: 10.1016/j.mito.2021.09.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Revised: 09/17/2021] [Accepted: 09/27/2021] [Indexed: 12/11/2022]
Abstract
Mitochondria are ubiquitous membrane-bound organelles that not only play a key role in maintaining cellular energy homeostasis and metabolism but also in signaling and apoptosis. Aryl hydrocarbons receptors (AhRs) are ligand-activated transcription factors that recognize a wide variety of xenobiotics, including polyaromatic hydrocarbons and dioxins, and activate diverse detoxification pathways. These receptors are also activated by natural dietary compounds and endogenous metabolites. In addition, AhRs can modulate the expression of a diverse array of genes related to mitochondrial biogenesis and function. The aim of the present review is to analyze scientific data available on the AhR signaling pathway and its interaction with the intracellular signaling pathways involved in mitochondrial functions, especially those related to cell cycle progression and apoptosis. Various evidence have reported the crosstalk between the AhR signaling pathway and the nuclear factor κB (NF-κB), tyrosine kinase receptor signaling and mitogen-activated protein kinases (MAPKs). The AhR signaling pathway seems to promote cell cycle progression in the absence of exogenous ligands, whereas the presence of exogenous ligands induces cell cycle arrest. However, its effects on apoptosis are controversial since activation or overexpression of AhR has been observed to induce or inhibit apoptosis depending on the cell type. Regarding the mitochondria, although activation by endogenous ligands is related to mitochondrial dysfunction, the effects of endogenous ligands are not well understood but point towards antiapoptotic effects and inducers of mitochondrial biogenesis.
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Affiliation(s)
- Adeleh Sahebnasagh
- Clinical Research Center, Department of Internal Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Javad Hashemi
- Department of Pathobiology and Laboratory Sciences, School of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Amirhosein Khoshi
- Department of Clinical Biochemistry, School of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Fatemeh Saghafi
- Department of Clinical Pharmacy, Faculty of Pharmacy and Pharmaceutical Sciences Research Center, Shahid Sadoughi University of Medical Sciences, Yazd, Iran
| | - Razieh Avan
- Assistant Professor of Clinical Pharmacy, Department of Clinical Pharmacy, Medical Toxicology and Drug Abuse Research Center (MTDRC), Faculty of Pharmacy, Birjand University of Medical Sciences, Birjand, Iran
| | - Fatemeh Faramarzi
- Clinical Pharmacy Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Saeed Azimi
- Student Research Committee, Department of Clinical Pharmacy, Faculty of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Solomon Habtemariam
- Pharmacognosy Research Laboratories and Herbal Analysis Services, School of Science, University of Greenwich, Central Avenue, Chatham-Maritime, Kent ME4 4TB, United Kingdom
| | - Antoni Sureda
- Research Group in Community Nutrition and Oxidative Stress, University of the Balearic Islands and Health Research Institute of Balearic Islands (IdISBa), Palma de Mallorca, Spain; CIBER Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Madrid, Spain
| | - Maryam Khayatkashani
- School of Iranian Traditional Medicine, Tehran University of Medical Sciences, 14155-6559 Tehran, Iran
| | - Mohammadreza Safdari
- Department of Orthopedic Surgery, Faculty of Medicine, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Hassan Rezai Ghaleno
- Department of Surgery, Faculty of Medicine, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Hosseinali Soltani
- Department of General Surgery, Imam Ali Hospital, North Khorasan University of Medical Sciences, Bojnurd, Iran
| | - Hamid Reza Khayat Kashani
- Department of Neurosurgery, Imam Hossein Hospital, Shahid Beheshti University of Medical Sciences, Tehran, Iran.
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Ames J, Warner M, Mocarelli P, Brambilla P, Signorini S, Siracusa C, Huen K, Holland N, Eskenazi B. AHR gene-dioxin interactions and birthweight in the Seveso Second Generation Health Study. Int J Epidemiol 2018; 47:1992-2004. [PMID: 30124847 PMCID: PMC6280946 DOI: 10.1093/ije/dyy165] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2018] [Indexed: 12/22/2022] Open
Abstract
Background 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) is proposed to interfere with fetal growth via altered activity of the aryl hydrocarbon receptor (protein: AHR; gene: AHR) pathway which regulates diverse biological and developmental processes including xenobiotic metabolism. Genetic variation in AHR is an important driver of susceptibility to low birthweight in children exposed to prenatal smoking, but less is known about these genetic interactions with TCDD, AHR's most potent xenobiotic ligand. Methods The Seveso Women's Health Study (SWHS), initiated in 1996, is a cohort of 981 Italian women exposed to TCDD from an industrial explosion in July 1976. We measured TCDD concentrations in maternal serum collected close to the time of the accident. In 2008 and 2014, we followed up the SWHS cohort and collected data on birth outcomes of SWHS women with post-accident pregnancies. We genotyped 19 single nucleotide polymorphisms (SNPs) in AHR among the 574 SWHS mothers. Results Among 901 singleton births, neither SNPs nor TCDD exposure alone were significantly associated with birthweight. However, we found six individual SNPs in AHR which adversely modified the association between maternal TCDD and birthweight, implicating gene-environment interaction. We saw an even stronger susceptibility to TCDD due to interaction when we examined the joint contribution of these SNPs in a risk allele score. These SNPs were all located in noncoding regions of AHR, particularly in proximity to the promoter. Conclusions This is the first study to demonstrate that genetic variation across the maternal AHR gene may shape fetal susceptibilities to TCDD exposure.
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Affiliation(s)
- Jennifer Ames
- Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA
| | - Marcella Warner
- Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA
| | - Paolo Mocarelli
- Department of Laboratory Medicine, University of Milan-Bicocca, Hospital of Desio, Desio-Milano, Italy
| | - Paolo Brambilla
- Department of Laboratory Medicine, University of Milan-Bicocca, Hospital of Desio, Desio-Milano, Italy
| | - Stefano Signorini
- Department of Laboratory Medicine, University of Milan-Bicocca, Hospital of Desio, Desio-Milano, Italy
| | - Claudia Siracusa
- Department of Laboratory Medicine, University of Milan-Bicocca, Hospital of Desio, Desio-Milano, Italy
| | - Karen Huen
- Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA
| | - Nina Holland
- Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA
| | - Brenda Eskenazi
- Center for Environmental Research and Children’s Health (CERCH), School of Public Health, University of California, Berkeley, CA, USA
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Choudhury AR, Singh KK. Mitochondrial determinants of cancer health disparities. Semin Cancer Biol 2017; 47:125-146. [PMID: 28487205 PMCID: PMC5673596 DOI: 10.1016/j.semcancer.2017.05.001] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 04/25/2017] [Accepted: 05/03/2017] [Indexed: 01/10/2023]
Abstract
Mitochondria, which are multi-functional, have been implicated in cancer initiation, progression, and metastasis due to metabolic alterations in transformed cells. Mitochondria are involved in the generation of energy, cell growth and differentiation, cellular signaling, cell cycle control, and cell death. To date, the mitochondrial basis of cancer disparities is unknown. The goal of this review is to provide an understanding and a framework of mitochondrial determinants that may contribute to cancer disparities in racially different populations. Due to maternal inheritance and ethnic-based diversity, the mitochondrial genome (mtDNA) contributes to inherited racial disparities. In people of African ancestry, several germline, population-specific haplotype variants in mtDNA as well as depletion of mtDNA have been linked to cancer predisposition and cancer disparities. Indeed, depletion of mtDNA and mutations in mtDNA or nuclear genome (nDNA)-encoded mitochondrial proteins lead to mitochondrial dysfunction and promote resistance to apoptosis, the epithelial-to-mesenchymal transition, and metastatic disease, all of which can contribute to cancer disparity and tumor aggressiveness related to racial disparities. Ethnic differences at the level of expression or genetic variations in nDNA encoding the mitochondrial proteome, including mitochondria-localized mtDNA replication and repair proteins, miRNA, transcription factors, kinases and phosphatases, and tumor suppressors and oncogenes may underlie susceptibility to high-risk and aggressive cancers found in African population and other ethnicities. The mitochondrial retrograde signaling that alters the expression profile of nuclear genes in response to dysfunctional mitochondria is a mechanism for tumorigenesis. In ethnic populations, differences in mitochondrial function may alter the cross talk between mitochondria and the nucleus at epigenetic and genetic levels, which can also contribute to cancer health disparities. Targeting mitochondrial determinants and mitochondrial retrograde signaling could provide a promising strategy for the development of selective anticancer therapy for dealing with cancer disparities. Further, agents that restore mitochondrial function to optimal levels should permit sensitivity to anticancer agents for the treatment of aggressive tumors that occur in racially diverse populations and hence help in reducing racial disparities.
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Affiliation(s)
| | - Keshav K Singh
- Departments of Genetics, University of Alabama at Birmingham, Birmingham, AL, 35294, USA; Departments of Pathology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA; Departments of Environmental Health, University of Alabama at Birmingham, Birmingham, AL, 35294, USA; Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA; Center for Aging, University of Alabama at Birmingham, Birmingham, AL, 35294, USA; UAB Comprehensive Cancer Center, University of Alabama at Birmingham, Birmingham, AL, 35294, USA; Birmingham Veterans Affairs Medical Center, Birmingham, AL, 35294, USA.
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Kobayashi S, Sata F, Sasaki S, Braimoh TS, Araki A, Miyashita C, Goudarzi H, Kobayashi S, Kishi R. Modification of adverse health effects of maternal active and passive smoking by genetic susceptibility: Dose-dependent association of plasma cotinine with infant birth size among Japanese women-The Hokkaido Study. Reprod Toxicol 2017; 74:94-103. [PMID: 28893607 DOI: 10.1016/j.reprotox.2017.09.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2017] [Revised: 09/05/2017] [Accepted: 09/07/2017] [Indexed: 12/27/2022]
Abstract
OBJECTIVES We aimed to assess the individual dose-response effects of eight maternal polymorphisms encoding polycyclic aromatic hydrocarbon-metabolizing and DNA-repair genes on prenatal cotinine levels according to infant birth size. METHODS In total, 3263 Japanese pregnant women were assigned to five groups based on plasma cotinine levels during the 8th month of pregnancy, as measured using ELISA (cut-offs: 0.21, 0.55, 11.48, and 101.67ng/mL). Analyses were performed using multiple linear regression. RESULTS Birth weight reduction showed a dose-dependent relationship with prenatal cotinine levels (P for trend<0.001). When considering the specific aromatic hydrocarbon receptor (AHR) (G>A, Arg554Lys; db SNP ID: rs2066853) and X-ray cross-complementing gene 1 (XRCC1) (C>T, Arg194Trp, rs1799782) genotypes, a larger birth weight reduction was noted among infants born to mothers with the highest cotinine level. CONCLUSION Infants born to women with specific AHR and XRCC1 genotypes may have higher genetic risks for birth weight reduction.
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Affiliation(s)
- Sumitaka Kobayashi
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan; Department of Public Health Sciences, Hokkaido University Graduate School of Medicine, North-15, West-7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan
| | - Fumihiro Sata
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan; Health Center, Chuo University, 42-8, Ichigaya-Hommura-cho, Shinjuku-ku, Tokyo 162-8473, Japan
| | - Seiko Sasaki
- Department of Public Health Sciences, Hokkaido University Graduate School of Medicine, North-15, West-7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan
| | - Titilola Serifat Braimoh
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan; Department of Public Health Sciences, Hokkaido University Graduate School of Medicine, North-15, West-7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan
| | - Atsuko Araki
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Chihiro Miyashita
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Houman Goudarzi
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Sachiko Kobayashi
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Reiko Kishi
- Center for Environmental and Health Sciences, Hokkaido University, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan.
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Kobayashi S, Sata F, Miyashita C, Sasaki S, Ban S, Araki A, Goudarzi H, Kajiwara J, Todaka T, Kishi R. Dioxin-metabolizing genes in relation to effects of prenatal dioxin levels and reduced birth size: The Hokkaido study. Reprod Toxicol 2016; 67:111-116. [PMID: 27939992 DOI: 10.1016/j.reprotox.2016.12.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 11/19/2016] [Accepted: 12/05/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVES We investigated the effects of maternal polymorphisms in 3 genes encoding dioxin-metabolizing enzymes in relation to prenatal dioxin levels on infant birth size in Japan. METHODS We examined the relationship between dioxin exposure and birth size in relation to the polymorphisms in the genes encoding aromatic hydrocarbon receptor (AHR [G>A, Arg554Lys]), cytochrome P450 (CYP) 1A1 (T6235C), and glutathione S-transferase mu 1 (GSTM1; Non-null/null) in 421 participants using multiple linear regression models. RESULTS In mothers carrying the GSTM1 null genotype, a ten-fold increase in total dioxin toxic equivalency was correlated with a decrease in birth weight of -345g (95% confidence interval: -584, -105). CONCLUSIONS We observed adverse effects of maternal GSTM1 null genotype on birth weight in the presence of dioxins exposure during pregnancy.
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Affiliation(s)
- Sumitaka Kobayashi
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo 060-0812, Japan
| | - Fumihiro Sata
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo 060-0812, Japan; Health Center, Chuo University, 42-8, Ichigaya-Hommura-cho, Shinjuku-ku, Tokyo 162-8473, Japan
| | - Chihiro Miyashita
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo 060-0812, Japan
| | - Seiko Sasaki
- Department of Public Health, Hokkaido University Graduate School of Medicine, North-15, West-7, Kita-ku, Sapporo 060-8638, Japan
| | - Susumu Ban
- Faculty of Pharmaceutical Sciences, Suzuka University of Medical Science, 3500-3, Minami-Tamagaki-cho, Suzuka 513-8670, Japan
| | - Atsuko Araki
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo 060-0812, Japan
| | - Houman Goudarzi
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo 060-0812, Japan
| | - Jumboku Kajiwara
- Fukuoka Institute of Health and Environmental Sciences, Mukaizano 39, Dazaifu 818-0135, Japan
| | - Takashi Todaka
- Department of Dermatology, Graduate School of Medical Sciences, Kyushu University, Maidashi 3-1-1, Higashi-ku, Fukuoka 812-8582, Japan
| | - Reiko Kishi
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo 060-0812, Japan.
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Kobayashi S, Sata F, Sasaki S, Braimoh TS, Araki A, Miyashita C, Goudarzi H, Kobayashi S, Kishi R. Combined effects of AHR, CYP1A1, and XRCC1 genotypes and prenatal maternal smoking on infant birth size: Biomarker assessment in the Hokkaido Study. Reprod Toxicol 2016; 65:295-306. [PMID: 27592400 DOI: 10.1016/j.reprotox.2016.08.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 08/16/2016] [Accepted: 08/30/2016] [Indexed: 10/21/2022]
Abstract
OBJECTIVES We investigated the individual and combined effects of maternal polymorphisms encoding the aromatic hydrocarbon receptor (AHR; rs2066853), cytochrome P450 (CYP) 1A1 (rs1048963), and the X-ray-complementing gene 1 (XRCC1; rs1799782) and prenatal smoking in relation to infant birth size. METHODS Totally, 3263 participants (1998 non-smokers and 1265 smokers) were included in the study between 2003 and 2007. Two groups of mothers were distinguished by plasma cotinine levels by ELISA measured during the third trimester (cut-off=11.48ng/mL). We conducted data analysis using multiple linear regression models. RESULTS Infants whose mothers smoked and had AHR-GG, CYP1A1-AG/GG, and XRCC1-CT/TT genotypes weighed, -145g less than those born of mothers who did not smoke and had the AHR-GA/AA, CYP1A1-AA, and XRCC1-CC genotypes (95% CI: -241, -50). CONCLUSIONS We demonstrated that infants whose mothers smoked during pregnancy with the combination of AHR, CYP1A1, and XRCC1 polymorphisms had lower birth size.
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Affiliation(s)
- Sumitaka Kobayashi
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan; Department of Public Health Sciences, Hokkaido University Graduate School of Medicine, North-15, West-7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan
| | - Fumihiro Sata
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan; Health Center, Chuo University, 42-8, Ichigaya-Hommura-cho, Shinjuku-ku, Tokyo 162-8473, Japan
| | - Seiko Sasaki
- Department of Public Health Sciences, Hokkaido University Graduate School of Medicine, North-15, West-7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan
| | - Titilola Serifat Braimoh
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan; Department of Public Health Sciences, Hokkaido University Graduate School of Medicine, North-15, West-7, Kita-ku, Sapporo, Hokkaido 060-8638, Japan
| | - Atsuko Araki
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Chihiro Miyashita
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Houman Goudarzi
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Sachiko Kobayashi
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan
| | - Reiko Kishi
- Hokkaido University Center for Environmental and Health Sciences, North-12, West-7, Kita-ku, Sapporo, Hokkaido 060-0812, Japan.
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Role of aryl hydrocarbon receptor polymorphisms on TCDD-mediated CYP1B1 induction and IgM suppression by human B cells. Toxicol Appl Pharmacol 2016; 309:15-23. [PMID: 27535091 DOI: 10.1016/j.taap.2016.08.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/14/2022]
Abstract
Previous studies have demonstrated that most of the intraspecies variation in sensitivity to the toxic effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), including suppression of antibody responses, in murine models is due to single nucleotide polymorphisms (SNPs) within the aryl hydrocarbon receptor (AhR) gene. The underlying reason for variation in sensitivity to TCDD-induced suppression of IgM responses among humans is not well understood, but is thought, in part, to be a result of different polymorphic forms of the AhR expressed by different individuals. In this study, the functional properties of six (P517S, R554K, V570I, V570I+P517S, R554K+V570I and P517S+R554K+V570I) human AhR variants were examined in the human B cell line, SKW 6.4. TCDD-induced Cyp1B1 and Cyp1A2 mRNA expression levels and Cyp1B1-regulated reporter gene activity, used for comparative purposes, were markedly lower in SKW cells containing the R554K SNP than in SKW-AHR(+) (control AhR) cells. Furthermore, all AhR variants were able to mediate TCDD-induced suppression of the IgM response; however, a combined P517S+R554K+V570I variant partially reduced sensitivity to TCDD-mediated suppression of IgM secretion. Collectively, our findings show that the R554K human AhR SNP alone altered sensitivity of human B cells to TCDD-mediated induction of Cyp1B1 and Cyp1A2. By contrast, attenuation of TCDD-induced IgM suppression required a combination of all three SNPs P517S, R554K, and V570I.
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Hubbard TD, Murray IA, Bisson WH, Sullivan AP, Sebastian A, Perry GH, Jablonski NG, Perdew GH. Divergent Ah Receptor Ligand Selectivity during Hominin Evolution. Mol Biol Evol 2016; 33:2648-58. [PMID: 27486223 DOI: 10.1093/molbev/msw143] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
We have identified a fixed nonsynonymous sequence difference between humans (Val381; derived variant) and Neandertals (Ala381; ancestral variant) in the ligand-binding domain of the aryl hydrocarbon receptor (AHR) gene. In an exome sequence analysis of four Neandertal and Denisovan individuals compared with nine modern humans, there are only 90 total nucleotide sites genome-wide for which archaic hominins are fixed for the ancestral nonsynonymous variant and the modern humans are fixed for the derived variant. Of those sites, only 27, including Val381 in the AHR, also have no reported variability in the human dbSNP database, further suggesting that this highly conserved functional variant is a rare event. Functional analysis of the amino acid variant Ala381 within the AHR carried by Neandertals and nonhuman primates indicate enhanced polycyclic aromatic hydrocarbon (PAH) binding, DNA binding capacity, and AHR mediated transcriptional activity compared with the human AHR. Also relative to human AHR, the Neandertal AHR exhibited 150-1000 times greater sensitivity to induction of Cyp1a1 and Cyp1b1 expression by PAHs (e.g., benzo(a)pyrene). The resulting CYP1A1/CYP1B1 enzymes are responsible for PAH first pass metabolism, which can result in the generation of toxic intermediates and perhaps AHR-associated toxicities. In contrast, the human AHR retains the ancestral sensitivity observed in primates to nontoxic endogenous AHR ligands (e.g., indole, indoxyl sulfate). Our findings reveal that a functionally significant change in the AHR occurred uniquely in humans, relative to other primates, that would attenuate the response to many environmental pollutants, including chemicals present in smoke from fire use during cooking.
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Affiliation(s)
- Troy D Hubbard
- Department of Veterinary and Biomedical Sciences and Center for Molecular Toxicology and Carcinogenesis, Pennsylvania State University
| | - Iain A Murray
- Department of Veterinary and Biomedical Sciences and Center for Molecular Toxicology and Carcinogenesis, Pennsylvania State University
| | - William H Bisson
- Department of Environmental and Molecular Toxicology, Oregon State University
| | | | | | - George H Perry
- Department of Biology, Pennsylvania State University Department of Anthropology, Pennsylvania State University
| | | | - Gary H Perdew
- Department of Veterinary and Biomedical Sciences and Center for Molecular Toxicology and Carcinogenesis, Pennsylvania State University
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11
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Aftabi Y, Colagar AH, Mehrnejad F. An in silico approach to investigate the source of the controversial interpretations about the phenotypic results of the human AhR-gene G1661A polymorphism. J Theor Biol 2016; 393:1-15. [PMID: 26776670 DOI: 10.1016/j.jtbi.2016.01.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2015] [Revised: 12/11/2015] [Accepted: 01/01/2016] [Indexed: 12/21/2022]
Abstract
Aryl hydrocarbon receptor (AhR) acts as an enhancer binding ligand-activated intracellular receptor. Chromatin remodeling components and general transcription factors such as TATA-binding protein (TBP) are evoked on AhR-target genes by interaction with its flexible transactivation domain (TAD). AhR-G1661A single nucleotide polymorphism (SNP: rs2066853) causes an arginine to lysine substitution in the acidic sub-domain of TAD at position 554 (R554K). Although, numerous studies associate the SNP with some abnormalities such as cancer, other reliable investigations refuse the associations. Consequently, the interpretation of the phenotypic results of G1661A-transition has been controversial. In this study, an in silico analysis were performed to investigate the possible effects of the transition on AhR-mRNA, protein structure, interaction properties and modifications. The analysis revealed that the R554K substitution affects secondary structure and solvent accessibility of adjacent residues. Also, it causes to decreasing of the AhR stability; altering the hydropathy features of the local sequence and changing the pattern of the residues at the binding site of the TAD-acidic sub-domain. Generating of new sites for ubiquitination and acetylation for AhR-K554 variant respectively at positions 544 and 560 was predicted. Our findings intensify the idea that the AhR-G1661A transition may affects AhR-TAD interactions, especially with the TBP, which influence AhR-target genes expression. However, the previously reported flexibility of the modular TAD could act as an intervening factor, moderate the SNP effects and causes distinct outcomes in different individuals and tissues.
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Affiliation(s)
- Younes Aftabi
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Post Code: 47416-95447, Mazandaran, Iran
| | - Abasalt Hosseinzadeh Colagar
- Department of Molecular and Cell Biology, Faculty of Basic Sciences, University of Mazandaran, Babolsar, Post Code: 47416-95447, Mazandaran, Iran.
| | - Faramarz Mehrnejad
- Department of Life Science Engineering, Faculty of New Sciences & Technologies, University of Tehran, P.O. Box: 14395-1561, Tehran, Iran
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12
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Huang S, Shui X, He Y, Xue Y, Li J, Li G, Lei W, Chen C. AhR expression and polymorphisms are associated with risk of coronary arterial disease in Chinese population. Sci Rep 2015; 5:8022. [PMID: 25620626 PMCID: PMC4306136 DOI: 10.1038/srep08022] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Accepted: 12/29/2014] [Indexed: 11/15/2022] Open
Abstract
The aryl hydrocarbon receptor (AhR) mediates the control of environmental toxicity, and modulates the development and pathogenesis of the cardiovascular system. However, little is known about the role of AhR in coronary arterial disease (CAD) susceptibility. We therefore conducted a case-control study in a Chinese population, and assessed the potential association between AhR variants and CAD susceptibility. Compared with the controls, circulating AhR expression was found to be significantly increased in patients with CAD and its subtypes including ST-segment and non-ST-segment elevation myocardial infarction, and stable and unstable angina pectoris. Receiver operating characteristic (ROC) analysis to evaluate the effect of AhR on CAD progression showed it to be a potent biomarker for CAD. Genotype frequencies of AhR rs2066853 differed significantly between CAD and control subjects, while smoking and hyperlipidemia markedly promoted CAD risk relative to the AhR polymorphism. Moreover, a significant difference in AhR variant distribution was observed between the four CAD subtypes with different severities. The expression level and functional polymorphisms of circulating AhR may affect the susceptibility and progression of CAD in Chinese populations. This provides a novel view of the etiology and epidemiology of CAD, and will contribute to the diagnosis and therapy of this severe disease.
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Affiliation(s)
- Shian Huang
- 1] Laboratory of Cardiovascular Diseases, Guangdong Medical College, Zhanjiang 524001, China [2] Department of Cardiovascular Medicine, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China
| | - Xiaorong Shui
- Laboratory of Vascular Surgery, Guangdong Medical College, Zhanjiang 524001, China
| | - Yuan He
- Laboratory of Cardiovascular Diseases, Guangdong Medical College, Zhanjiang 524001, China
| | - Yiqiang Xue
- Department of Cardiovascular Medicine, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China
| | - Jianwen Li
- Laboratory of Vascular Surgery, Guangdong Medical College, Zhanjiang 524001, China
| | - Guoming Li
- Department of Cardiovascular Medicine, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China
| | - Wei Lei
- 1] Laboratory of Cardiovascular Diseases, Guangdong Medical College, Zhanjiang 524001, China [2] Department of Cardiovascular Medicine, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China
| | - Can Chen
- 1] Laboratory of Cardiovascular Diseases, Guangdong Medical College, Zhanjiang 524001, China [2] Department of Cardiovascular Medicine, Affiliated Hospital of Guangdong Medical College, Zhanjiang 524001, China
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Association of Aryl Hydrocarbon Receptor Gene Polymorphism With the Neurobehavioral Function and Autonomic Nervous System Function Changes Induced by Benzo[a]Pyrene Exposure in Coke Oven Workers. J Occup Environ Med 2013; 55:265-71. [DOI: 10.1097/jom.0b013e318278272f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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14
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Ziv-Gal A, Gallicchio L, Miller SR, Zacur HA, Flaws JA. Genetic polymorphisms in the aryl hydrocarbon receptor signaling pathway as potential risk factors of menopausal hot flashes. Am J Obstet Gynecol 2012; 207:202.e9-202.e18. [PMID: 22840970 DOI: 10.1016/j.ajog.2012.05.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Revised: 05/10/2012] [Accepted: 05/23/2012] [Indexed: 02/06/2023]
Abstract
OBJECTIVE We sought to determine if genetic polymorphisms in the aryl hydrocarbon receptor signaling pathway are associated with menopausal hot flashes via hormone levels. STUDY DESIGN Women (n = 639) aged 45-54 years completed a study survey and provided blood for genetic and hormone analyses. The associations were analyzed using multivariable logistic regression and generalized linear models. RESULTS Women carrying CYP1B1 (rs1800440) GG genotype had 3-fold greater odds of experiencing hot flashes for ≥1 year compared to the AA genotype (adjusted odds ratio [OR], 3.05; 95% confidence interval [CI], 1.12-8.25). Adding serum estradiol concentrations to the confounder-adjusted model resulted in a nonsignificant association (adjusted OR, 2.59; 95% CI, 0.91-7.18). Carriers of both CYP1B1 (rs1800440) G and CYP1B1 (rs1058636) G alleles had higher odds of experiencing hot flashes for ≥1 year compared to women homozygous for the major alleles (adjusted OR, 1.77; 95% CI, 1.06-2.96), even after adjustment for serum estradiol. CONCLUSION CYP1B1 is associated with menopausal hot flashes via pathways that may involve changes in serum estradiol concentration.
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Affiliation(s)
- Ayelet Ziv-Gal
- Department of Comparative Biosciences, University of Illinois, Urbana, IL 61802, USA
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15
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Gu A, Ji G, Long Y, Zhou Y, Shi X, Song L, Wang X. Assessment of an Association between an Aryl Hydrocarbon Receptor Gene (AHR) Polymorphism and Risk of Male Infertility. Toxicol Sci 2011; 122:415-21. [DOI: 10.1093/toxsci/kfr137] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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16
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Celius T, Matthews J. Functional analysis of six human aryl hydrocarbon receptor variants in human breast cancer and mouse hepatoma cell lines. Toxicology 2010; 277:59-65. [DOI: 10.1016/j.tox.2010.08.015] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2010] [Revised: 08/10/2010] [Accepted: 08/26/2010] [Indexed: 10/19/2022]
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17
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Sulentic CEW, Kaminski NE. The long winding road toward understanding the molecular mechanisms for B-cell suppression by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Toxicol Sci 2010; 120 Suppl 1:S171-91. [PMID: 20952503 DOI: 10.1093/toxsci/kfq324] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Suppression of humoral immune responses by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) was first reported in the mid-1970s. Since this initial observation, much effort has been devoted by many laboratories toward elucidation of the cellular and molecular mechanisms responsible for the profound impairment of humoral immune responses by TCDD, which is characterized by decreased B cell to plasma cell differentiation and suppression of immunoglobulin production. These efforts have led to a significant body of research demonstrating a direct effect of TCDD on B-cell maturation and function as well as a requisite but as yet undefined role of the aryl hydrocarbon receptor (AhR) in these effects. Likewise, a number of molecular targets putatively involved in mediating B-cell dysfunction by TCDD, and other AhR ligands, have been identified. However, our current understanding has primarily relied on findings from mouse models, and the translation of this knowledge to effects on human B cells and humoral immunity in humans is less clear. Therefore, a current challenge is to determine how TCDD and the AhR affect human B cells. Efforts have been made in this direction but continued progress in developing adequate human models is needed. An in-depth discussion of these advances and limitations in elucidating the cellular and molecular mechanisms putatively involved in the suppression of B-cell function by TCDD as well as the implications on human diseases associated in epidemiological studies with exposure to TCDD and dioxin-like compounds is the primary focus of this review.
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Affiliation(s)
- Courtney E W Sulentic
- Department of Pharmacology & Toxicology, Boonshoft School of Medicine, Wright State University, Dayton, Ohio 45435, USA
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18
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Lu H, Crawford RB, Suarez-Martinez JE, Kaplan BLF, Kaminski NE. Induction of the aryl hydrocarbon receptor-responsive genes and modulation of the immunoglobulin M response by 2,3,7,8-tetrachlorodibenzo-p-dioxin in primary human B cells. Toxicol Sci 2010; 118:86-97. [PMID: 20702590 DOI: 10.1093/toxsci/kfq234] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Past studies in rodent models identified the suppression of primary humoral immune responses as one of the most sensitive sequela associated with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure. Yet, the sensitivity of humoral immunity to TCDD in humans represents an important toxicological data gap. Therefore, the objectives of this investigation were two-fold. The first was to assess the induction of known aryl hydrocarbon receptor (AHR)-responsive genes in primary human B cells as a measure of early biological responses to TCDD. The second was to evaluate the direct effect of TCDD on CD40 ligand-induced immunoglobulin M (IgM) secretion by human primary B cells. The effects of TCDD on induction of AHR-responsive genes and suppression of the IgM response were also compared with B cells from a TCDD-responsive mouse strain, C57BL/6. AHR-responsive genes in human B cells exhibited slower kinetics and reduced magnitude of induction by TCDD when compared with mouse B cells. Evaluation of B-cell function from 12 donors identified two general phenotypes; the majority of donors exhibited similar sensitivity to suppression by TCDD of the IgM response as mouse B cells, which was not attributable to decreased B-cell proliferation. In a minority of donors, no suppression of the IgM response by TCDD was observed. Although donor-to-donor variation in sensitivity to TCDD was observed, human B cells from the majority of donors evaluated showed impairment of effector function by TCDD. Collectively, data presented in this series of studies demonstrate that TCDD impairs the humoral immunity of humans by directly targeting B cells.
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Affiliation(s)
- Haitian Lu
- Department of Pharmacology and Toxicology, Center for Integrative Toxicology, Michigan State University, East Lansing, Michigan 48824, USA
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19
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Sangrajrang S, Sato Y, Sakamoto H, Ohnami S, Laird NM, Khuhaprema T, Brennan P, Boffetta P, Yoshida T. Genetic polymorphisms of estrogen metabolizing enzyme and breast cancer risk in Thai women. Int J Cancer 2009; 125:837-43. [PMID: 19415745 DOI: 10.1002/ijc.24434] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Estrogen and its metabolites are believed to play important roles in breast cancer, and its determinants include both genetic and lifestyle factors. The objective of the study is to investigate the association of breast cancer risk in Thailand with genetic polymorphisms in several genes involved in estrogen synthesis and metabolism. Five hundred and seventy patients with histopathologically confirmed breast cancer and 497 controls were included in the present study. Forty single nucleotide polymorphisms (SNPs) in the CYP1A1, CYP1A2, CYP1B1, CYP17, CYP19, CYP2C9, CYP2C19, AhR, ESR1, PGR, ERRG, COMT, HSD17B1, HSD17B2, EPHX1 and NQO1 genes were genotyped. Association of genotypes with breast cancer risk was evaluated using multivariate logistic regression, which suggested an altered risk for the following SNPs [gene, odds ratio (OR) and 95% confidence interval are shown]: heterozygote carriers of rs4917623 [CYP2C19, OR = 1.38 (1.04-1.84)], rs2066853 [AhR, OR = 1.34 (1.02-1.76)] and rs1857407 [ERRG, (OR = 0.72 (0.55-0.96)]; homozygote carriers of rs762551 [CYP1A2, OR = 2.75 (1.47-5.14)], rs4917623 [CYP2C19, OR = 1.48 (1.00-2.19) and rs945453 [ERRG, OR = 1.66 (1.04-2.65)]. In addition, a stratified analysis by menopausal status indicated that the association of the CYP1A2 (rs762551) and CYP17 (rs743572) polymorphisms with breast cancer risk were mainly evident in premenopausal, while ERRG (rs1857407) was significant in postmenopausal women. These findings suggest that CYP1A2, CYP2C19, AhR, ERRG and CYP17 polymorphisms may play an important role in estrogen metabolism and modify individual susceptibility to breast cancer in Thai women.
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20
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Joo SP, Kim TS, Lee IK, Lee JK, Seo BR, Kim JH, Kim SH. The role of collagen type I α2 polymorphisms: intracranial aneurysms in Koreans. ACTA ACUST UNITED AC 2009; 72:48-53; discussion 53. [DOI: 10.1016/j.surneu.2009.02.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Revised: 01/08/2009] [Accepted: 02/05/2009] [Indexed: 10/20/2022]
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21
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Chen G, Shin JA. AhR/Arnt:XRE interaction: turning false negatives into true positives in the modified yeast one-hybrid assay. Anal Biochem 2008; 382:101-6. [PMID: 18722998 DOI: 10.1016/j.ab.2008.07.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2008] [Accepted: 07/25/2008] [Indexed: 10/21/2022]
Abstract
Given the frequent occurrence of false negatives in yeast genetic assays, it is both interesting and practical to address the possible mechanisms of false negatives and, more important, to turn false negatives into true positives. We recently developed a modified yeast one-hybrid system (MY1H) useful for investigation of simultaneous protein-protein and protein:DNA interactions in vivo. We coexpressed the basic helix-loop-helix/Per-Arnt-Sim (bHLH/PAS) domains of aryl hydrocarbon receptor (AhR) and aryl hydrocarbon receptor nuclear translocator (Arnt)--namely NAhR and NArnt, respectively--which are known to form heterodimers and bind the cognate xenobiotic response element (XRE) sequence both in vitro and in vivo, as a positive control in the study of XRE-binding proteins in the MY1H system. However, we observed negative results, that is, no positive signal detected from binding of the NAhR/NArnt heterodimer and XRE site. We demonstrate that by increasing the copy number of XRE sites integrated into the yeast genome and using double GAL4 activation domains, the NAhR/NArnt heterodimer forms and specifically binds the cognate XRE sequence, an interaction that is now clearly detectable in the MY1H system. This methodology may be helpful in troubleshooting and correcting false negatives that arise from unproductive transcription in yeast genetic assays.
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Affiliation(s)
- Gang Chen
- Department of Chemistry, University of Toronto, Mississauga, Ont., Canada L5L1C6
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22
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Tiido T, Rignell-Hydbom A, Jönsson BAG, Rylander L, Giwercman A, Giwercman YL. Modifying effect of the AR gene trinucleotide repeats and SNPs in the AHR and AHRR genes on the association between persistent organohalogen pollutant exposure and human sperm Y : X ratio. Mol Hum Reprod 2007; 13:223-9. [PMID: 17244640 DOI: 10.1093/molehr/gal114] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Persistent organohalogen pollutants (POPs) have been suggested to be involved in changing the proportion of ejaculated Y-bearing sperm. The androgen receptor (AR), aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor repressor (AHRR) may modulate the effect of POPs with regard to previously observed sperm Y:X ratio changes. The objective of this study was to investigate whether sperm Y:X ratio changes in subjects exposed to 2,2'4,4'5,5'-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p'-DDE) were modified by polymorphisms in the AR, AHR and AHRR genes. Semen for analysis of Y- and X-bearing sperm by two-colour fluorescence in situ hybridization and blood for leukocyte DNA genotyping and analysis of CB-153 and p,p'-DDE concentrations were obtained from 195 Swedish fishermen. The polymorphic CAG and GGN repeats in the AR and the R554K and P185A single-nucleotide polymorphisms in the AHR and AHRR genes, respectively, were determined by direct sequencing and allele-specific PCR. The effect of p,p'-DDE was modified by CAG or GGN repeat category in relation to the proportion of Y-bearing sperm (P = 0.005 and 0.02 for CAG and GGN, respectively). Moreover, p,p'-DDE, but not CB-153, levels were associated with Y-sperm proportion in men with CAG < 22 (P < 0.001), but not in those carrying CAG > or = 22 (P = 0.73). This association was even more pronounced in subjects carrying a short CAG repeat in combination with an AHRR G-allele. The association in regard to p,p'-DDE was found for GGN = 23 but not for the GGN < 23 or GGN > 23 subgroups (P = 0.01, 0.44 and 0.99, respectively). In conclusion The endocrine-disrupting action of POPs, in relation to the observed changes in sperm Y:X ratio, may be modulated by the genes involved in sex steroid and dioxin-mediated pathways.
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MESH Headings
- Basic Helix-Loop-Helix Transcription Factors
- Chromosomes, Human, X/drug effects
- Chromosomes, Human, Y/drug effects
- Cohort Studies
- Dichlorodiphenyl Dichloroethylene/toxicity
- Environmental Exposure
- Environmental Pollutants/blood
- Environmental Pollutants/toxicity
- Genotype
- Humans
- Hydrocarbons, Chlorinated/blood
- Hydrocarbons, Chlorinated/toxicity
- In Situ Hybridization, Fluorescence
- Male
- Polychlorinated Biphenyls/toxicity
- Polymerase Chain Reaction
- Polymorphism, Single Nucleotide
- Receptors, Androgen/genetics
- Receptors, Androgen/metabolism
- Receptors, Aryl Hydrocarbon/genetics
- Receptors, Aryl Hydrocarbon/metabolism
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Spermatogenesis/drug effects
- Spermatozoa/drug effects
- Spermatozoa/metabolism
- Sweden
- Trinucleotide Repeats
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Affiliation(s)
- T Tiido
- Department of Clinical Sciences, Molecular Reproductive Medicine Research Unit, Malmö University Hospital, Sweden.
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Chen Y, Bai Y, Yuan J, Chen W, Sun J, Wang H, Liang H, Guo L, Yang X, Tan H, Su Y, Wei Q, Wu T. Association of Polymorphisms in AhR, CYP1A1, GSTM1, and GSTT1 Genes with Levels of DNA Damage in Peripheral Blood Lymphocytes among Coke-Oven Workers. Cancer Epidemiol Biomarkers Prev 2006; 15:1703-7. [PMID: 16985033 DOI: 10.1158/1055-9965.epi-06-0291] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Accumulating evidence has shown that both DNA damage caused by the metabolites of polycyclic aromatic hydrocarbons (PAH) and genetic polymorphisms in PAH-metabolic genes contribute to individual susceptibility to PAH-induced carcinogenesis. However, the functional relevance of genetic polymorphisms in PAH-metabolic genes in exposed individuals is still unclear. In this study of 240 coke-oven workers (the exposed group) and 123 non-coke-oven workers (the control group), we genotyped for polymorphisms in the AhR, CYP1A1, GSTM1, and GSTT1 genes by PCR methods, and determined the levels of DNA damage in peripheral blood lymphocytes using the alkaline comet assay. We found that the ln-transformed Olive tail moment (Olive TM) values in the exposed group were significantly higher than those in the control group (P < 0.001). Furthermore, in the exposed group, the Olive TM values in subjects with the AhR Lys(554) variant genotype were higher than those with the AhR Arg(554)/Arg(554) genotype (P = 0.021). Similarly, the Olive TM values in the non-coke-oven workers with the CYP1A1 MspI CC + CT genotype were lower than the values of those with the CYP1A1 MspI TT genotype (P = 0.005). However, these differences were not evident for GSTM1 and GSTT1. These results suggested that the polymorphism of AhR might modulate the effects of PAHs in the exposed group; however, the underlying molecular mechanisms by which this polymorphism may have affected the levels of PAH-induced DNA damage warrant further investigation.
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Affiliation(s)
- Yongwen Chen
- Institute of Occupational Medicine, School of Public Health, Tongji Medical College, Huazhong University of Science and Technology, Hangkong Road 13, Wuhan, Hubei 430030, People's Republic of China
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Dragin N, Dalton TP, Miller ML, Shertzer HG, Nebert DW. For dioxin-induced birth defects, mouse or human CYP1A2 in maternal liver protects whereas mouse CYP1A1 and CYP1B1 are inconsequential. J Biol Chem 2006; 281:18591-600. [PMID: 16636061 DOI: 10.1074/jbc.m601159200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin) induces cleft palate and hydronephrosis in mice, when exposed in utero; these effects are mediated by the aryl hydrocarbon receptor. The Cyp1a1, Cyp1a2, and Cyp1b1 genes are up-regulated by the aryl hydrocarbon receptor. To elucidate their roles in dioxin-induced teratogenesis, we compared Cyp1a1(-/-), Cyp1a2(-/-), and Cyp1b1(-/-) knock-out mice with Cyp1(+/+) wild-type mice. Dioxin was administered (25 microg/kg, gavage) on gestational day 10, and embryos were examined on gestational day 18. The incidence of cleft palate and hydronephrosis was not significantly different in fetuses from Cyp1a1(-/-), Cyp1b1(-/-), and Cyp1(+/+) wild-type mice. To fetuses carried by Cyp1a2(-/-) dams, however, this dose of dioxin was lethal; this effect was absolutely dependent on the maternal Cyp1a2 genotype and independent of the embryonic Cyp1a2 genotype. Dioxin levels were highest in adipose tissue, mammary gland, and circulating blood of Cyp1a2(-/-) mothers, compared with that in the Cyp1(+/+) mothers, who showed highest dioxin levels in liver. More dioxin reached the embryos from Cyp1a2(-/-) dams, compared with that from Cyp1(+/+) dams. Fetuses from Cyp1a2(-/-) dams exhibited a approximately 6-fold increased sensitivity to cleft palate, hydronephrosis, and lethality. Using the humanized hCYP1A1_1A2 transgenic mouse (expressing the human CYP1A1 and CYP1A2 genes in the absence of mouse Cyp1a2 gene), the teratogenic effects of dioxin reverted to the wild-type phenotype. These data indicate that maternal mouse hepatic CYP1A2, by sequestering dioxin and thus altering the pharmacokinetics, protects the embryos from toxicity and birth defects; substitution of the human CYP1A2 trans-gene provides the same protection. In contrast, neither CYP1A1 nor CYP1B1 appears to play a role in dioxin-mediated teratogenesis.
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Affiliation(s)
- Nadine Dragin
- Department of Environmental Health and Center for Environmental Genetics, University of Cincinnati Medical Center, Cincinnati, Ohio 45267-0056, USA
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25
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Long JR, Egan KM, Dunning L, Shu XO, Cai Q, Cai H, Dai Q, Holtzman J, Gao YT, Zheng W. Population-based case–control study of AhR (aryl hydrocarbon receptor) and CYP1A2 polymorphisms and breast cancer risk. Pharmacogenet Genomics 2006; 16:237-43. [PMID: 16538170 DOI: 10.1097/01.fpc.0000189803.34339.ed] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The aryl hydrocarbon receptor (AhR) is a key regulator of the transcriptional expression for the cytochrome P450 1 (CYP1) genes. CYP1A2 is one of the major CYP1 enzymes that catalyse 2-hydroxylation of estrogen, a hormone that plays a critical role in the etiology of breast cancer. In this study, we investigated whether two common polymorphisms in these two genes, CYP1A2*1F and AhR Lys554Arg, were associated with breast cancer risk in 1090 cases and 1183 controls, a subset of the population-based case-control study, the Shanghai Breast Cancer Study. Caffeine tests were performed in vivo in a subset of 236 study subjects to investigate the relationship of these two polymorphisms with CYP1A2 activity. For the AhR gene, the A (Lys) allele was associated with a decreased risk of breast cancer. Using the genotype GG as reference, odds ratios of 0.82 [95% confidence interval (CI)=0.69-0.99] for the AG genotype and 0.76 (95% CI=0.58-1.01) for the AA genotype (P for trend=0.018) were obtained. However, no association was observed between CYP1A2 genotypes and breast cancer risk, although the CYP1A2*1F polymorphism was found to be related to CYP1A2 activity. The geometric mean values for the caffeine metabolites ratio were 2.90, 2.30, and 1.95 for CC, AC, and AA genotypes, respectively (P for trend=0.024). In conclusion, the results from our study suggest that the AhR Lys554Arg polymorphism may be a genetic susceptibility factor for breast cancer, whereas CYP1A2*1F, which is a potentially functional single nucleotide polymorphism, may not be related to breast cancer risk.
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Affiliation(s)
- Ji-Rong Long
- Department of Medicine and Vanderbilt-Ingram Cancer Center, Vanderbilt University, 1161 21st Avenue South, Nashville, TN 37232, USA
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Connor KT, Aylward LL. Human response to dioxin: aryl hydrocarbon receptor (AhR) molecular structure, function, and dose-response data for enzyme induction indicate an impaired human AhR. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART B, CRITICAL REVIEWS 2006; 9:147-71. [PMID: 16613807 DOI: 10.1080/15287390500196487] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The aryl hydrocarbon receptor (AhR) mediates nearly all studied adverse effects of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and many related compounds. Binding of TCDD or related ligands to AhR is the key initiating event in downstream biochemical responses. The binding affinity of AhR for TCDD is specific to species and strain, and studies of human AhR demonstrate binding affinities approximately an order of magnitude or more lower than those observed in the most sensitive laboratory strains and species. Molecular genetic studies confirmed that human AhR shares key mutations with the DBA mouse strain that result in an "impaired" AhR (with respect to TCDD binding and responsiveness). Despite a number of polymorphisms in human AhR, the key "DBA-type" mutations appear to be a constant feature of the human AhR, and no polymorphisms have been identified that compensate for the impaired binding function conferred by these mutations. Consistent with the impaired binding status of the human AhR, human cells have consistently required approximately 10-fold higher concentrations of TCDD in vitro than rodent cells to respond with enzyme induction. Recent studies of in vivo enzyme induction-related endpoints in human populations with moderately and highly increased TCDD body burdens detected no relationship between these endpoints and TCDD body burdens at body-burden levels up to 250 ng TEQ/kg body weight, or approximately 25 times above the upper range of current general population background body burdens, while marked elevations in enzyme activity were observed in persons with body burdens above 750 ng TEQ/kg. In contrast, the more sensitive laboratory rodent strains and species exposed to TCDD exhibit significant enzyme induction at body burdens below 50 ng/kg. These interspecies data on the most sensitive and best understood response to binding of TCDD and related compounds to the AhR are consistent with the binding affinity and molecular structure data and support the hypothesis that the human AhR is less functional than the AhR of the more sensitive laboratory animals at a molecular level. Quantitative risk assessments involving interspecies extrapolation from sensitive laboratory species and strains should take these fundamental differences into account when margins of exposure and safety factors are considered.
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Sasaki S, Kondo T, Sata F, Saijo Y, Katoh S, Nakajima S, Ishizuka M, Fujita S, Kishi R. Maternal smoking during pregnancy and genetic polymorphisms in the Ah receptor, CYP1A1 and GSTM1 affect infant birth size in Japanese subjects. Mol Hum Reprod 2006; 12:77-83. [PMID: 16481407 DOI: 10.1093/molehr/gal013] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Genetic susceptibility to tobacco smoke might have relation to adverse pregnancy outcomes. To estimate the effects of maternal smoking and genetic polymorphisms on infant birth weight and length, we conducted a prospective cohort study of 293 women who delivered singleton live births in Sapporo, Japan. Birth weight and length were significantly lower among infants born to continuously smoking women having the aryl hydrocarbon receptor (AhR) wild type genotype (Arg/Arg; 211 g +/- 76 g; 1.2 cm +/- 0.4 cm, p < 0.01 and p < 0.01, respectively), the CYP1A1 variant genotype (m1/m2 + m2/m2; 170 g +/- 64 g, 0.8 cm +/- 0.3 cm, p < 0.01 and p < 0.05, respectively), or the GSTM1 null genotype (171 g +/- 58 g, 0.6 cm +/- 0.3 cm, p < 0.01 and p < 0.05, respectively). When combinations of these genotypes were considered, birth weight and length were significantly lower for infants of continuously smoking women in the AhR wild type + CYP1A1 variant group (315 g +/- 116 g; 1.7 cm +/- 0.6 cm, p < 0.01 and p < 0.01, respectively) and in the CYP1A1 variant + GSTM1 null group (237 g +/- 92 g; 1.3 cm +/- 0.5 cm, p < 0.05 and p < 0.01, respectively). These genotypes did not confer adverse effects among women who had never smoked; therefore, maternal smoking in combination with maternal AhR, CYP1A1 and GSTM1 genetic polymorphisms may adversely affect infant birth size.
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Affiliation(s)
- S Sasaki
- Department of Public Health, Graduate School of Medicine, Hokkaido University, Kita 15, Nishi 7, Kita-ku, Sapporo 060-8638, Japan
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Koyano S, Saito Y, Fukushima-Uesaka H, Ishida S, Ozawa S, Kamatani N, Minami H, Ohtsu A, Hamaguchi T, Shirao K, Yoshida T, Saijo N, Jinno H, Sawada JI. Functional analysis of six human aryl hydrocarbon receptor variants in a Japanese population. Drug Metab Dispos 2005; 33:1254-60. [PMID: 15860653 DOI: 10.1124/dmd.105.004655] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Aryl hydrocarbon receptor (AhR) is an important transcriptional regulator involved in the induction of CYP1A1, CYP1A2, CYP1B1, UGT1A1, and UGT1A6. In this study, functional properties of four novel naturally occurring human AhR variants (K401R, N487D, I514T, and K17T/R554K) were examined along with the single variants K17T and R554K. The luciferase reporter assay using the CYP1A1 promoter reporter in HeLa cells treated with beta-naphthoflavone or 3-methylcholanthrene, which are known as typical agonists for AhR, showed that reporter activities of the K401R and N487D variants were reduced to 40 to 58% of those of wild-type (WT) but not of the other variants. Similarly, the K401R and N487D variants also reduced the omeprazole-induced reporter activities to approximately 56 and 74% of those of the WT, respectively. The reduced activities of the two variants were probably caused by the reduced protein expression levels, since the protein levels of the K401R and N487D variants were approximately 52 and 47% of the WT, respectively, without any changes in their mRNA levels. The reduced protein levels were recovered by treatment with a proteasome inhibitor MG132 [N-benzoyloxycarbonyl (Z)-Leu-Leu-leucinal], suggesting that the reduced protein levels were caused by the accelerated proteasomal degradation by a proteasome. Together, the current data demonstrate that the K401R and N487D variants reduce their apparent transcriptional activities, both ligand-induced and omeprazole-induced activation, probably through reduced protein expression. Thus, these two variants may influence drug metabolism through reduced induction of CYP1A1 and other target enzymes.
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Affiliation(s)
- Satoru Koyano
- Project Team for Pharmacogenetics, National Institute of Health Sciences, 1-18-1 Kamiyoga, Setagaya-ku, Tokyo 158-8501, Japan.
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Berwick M, Matullo G, Song YS, Guarrera S, Dominguez G, Orlow I, Walker M, Vineis P. Association Between Aryl Hydrocarbon Receptor Genotype and Survival in Soft Tissue Sarcoma. J Clin Oncol 2004; 22:3997-4001. [PMID: 15459223 DOI: 10.1200/jco.2004.10.059] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Purpose Accumulating evidence shows that germline polymorphisms may affect survival in cancer. The purpose of this study was to investigate the association between polymorphisms in a group of candidate genes and survival with soft tissue sarcoma. Patients and Methods We measured single nucleotide polymorphisms in the metabolizing, detoxifying, and DNA repair pathways in 120 newly diagnosed patients with soft tissue sarcoma. We assessed polymorphisms in the aryl hydrocarbon receptor (AhR-Arg554Lys), null variants of the glutathione S-transferase superfamily (GSTM1 and GSTT1), x-ray repair cross-complementing 1 and 3, and Xeroderma pigmentosum, group D (XRCC1-Arg399Gln, XRCC3-Thr241Met, XPD-Lys751Gln). We followed the patients for survival for a median of 7.6 years. Results Cox proportional hazards models demonstrated that a polymorphism at codon 554 in exon 10 of the AhR was significantly and adversely associated with survival (hazard ratio, 2.2; 95% CI, 1.3 to 3.9; P < .01), even while accounting for major clinical characteristics such as tumor grade, tumor size, anatomic site, and patient age. Conclusion Further study of the role of the AhR polymorphism is warranted.
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Hahn ME, Karchner SI, Franks DG, Merson RR. Aryl hydrocarbon receptor polymorphisms and dioxin resistance in Atlantic killifish (Fundulus heteroclitus). ACTA ACUST UNITED AC 2004; 14:131-43. [PMID: 15077014 DOI: 10.1097/00008571-200402000-00007] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The aryl hydrocarbon receptor (AHR) gene encodes a ligand-activated transcription factor through which planar halogenated aromatic hydrocarbons (HAHs) such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as well as polynuclear aromatic hydrocarbons (PAHs) cause altered gene expression and toxicity. To understand the role of AHR genetic variability in differential sensitivity to HAHs and PAHs, we are currently studying a population of the teleost Fundulus heteroclitus (Atlantic killifish) that has evolved genetic resistance to the toxic and biochemical effects of these compounds. Here, we report that the killifish AHR1 locus is highly polymorphic and that the frequencies of the major allele types differ between dioxin-sensitive and dioxin-resistant populations. Twenty-five single nucleotide polymorphisms (SNPs), nine of which are non-synonymous, were identified in the AHR1 coding sequence. Seven identified alleles were assigned to three groups, designated AHR1*1, AHR1*2 and AHR1*3. AHR1*1 alleles were under-represented in a population of dioxin- and polychlorinated biphenyl (PCB)-resistant fish from a PCB-contaminated Superfund site (New Bedford Harbor, Massachusetts, USA) compared to dioxin-sensitive fish from a less contaminated reference site (Scorton Creek, Massachusetts, USA). To determine the possible role of these AHR1 variants in differential HAH sensitivity, we expressed representative variant proteins from the two most divergent allelic groups (AHR1*1 and AHR1*3) by in-vitro transcription and translation and assessed their functional properties. AHR1*1A and AHR1*3A proteins displayed similar binding capacities and affinities for [H]TCDD. In transient transfection assays using mammalian cells, AHR1*1A and AHR1*3A exhibited similar abilities to support TCDD-dependent transactivation of a luciferase reporter gene under control of AHR-responsive enhancer elements. We discuss the possibility of other functional differences in AHR1 variants or their interaction with other killifish loci (AHR2, AHRR) that may contribute to differences in dioxin sensitivity.
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Affiliation(s)
- Mark E Hahn
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts 02543-1049, USA.
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Fukushima-Uesaka H, Sai K, Maekawa K, Koyano S, Kaniwa N, Ozawa S, Kawamoto M, Kamatani N, Komamura K, Kamakura S, Kitakaze M, Tomoike H, Ueno K, Minami H, Ohtsu A, Shirao K, Yoshida T, Saijo N, Saito Y, Sawada JI. Genetic Variations of the AHR Gene Encoding Aryl Hydrocarbon Receptor in a Japanese Population. Drug Metab Pharmacokinet 2004; 19:320-6. [PMID: 15499202 DOI: 10.2133/dmpk.19.320] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Aryl hydrocarbon receptor (AhR), encoded by the AHR gene, is a transcriptional factor that induces various drug metabolizing enzymes in response to diverse endogenous and exogenous ligands. In order to identify genetic variations of the AHR gene, genomic DNA from 242 Japanese individuals was sequenced. We identified 32 single nucleotide variations, including 25 novel ones [7 were in the coding exons, 7 in the introns, 1 in the 5'-untranslated region (UTR), 5 in the 3'-UTR, 2 in the 5'-flanking region, and 3 in the 3'-flanking region] and a GGGGC repeat polymorphism (a novel microsatellite marker) in the promoter region. The novel nonsynonymous variations were 50A>C (Lys17Thr), 1202A>G (Lys401Arg), 1459A>G (Asn487Asp), and 1541T>C (Ile514Thr). The allele frequencies were 0.010 for 1459A>G (Asn487Asp) and 0.002 for the other 3 variations. Also detected in this analysis was the known nonsynonymous single nucleotide polymorphism 1661G>A (Arg554Lys) at a 0.444 frequency.
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Mimura J, Fujii-Kuriyama Y. Functional role of AhR in the expression of toxic effects by TCDD. BIOCHIMICA ET BIOPHYSICA ACTA 2003; 1619:263-8. [PMID: 12573486 DOI: 10.1016/s0304-4165(02)00485-3] [Citation(s) in RCA: 530] [Impact Index Per Article: 25.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cytochrome P450 1A1 (CYP1A1) is one of the xenobiotic metabolizing enzymes (XMEs), which is induced by polycyclic aromatic hydrocarbons (PAHs). The most potent inducer of CYP1A1 is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). In addition, TCDD induces a broad spectrum of biochemical and toxic effects, such as teratogenesis, immunosuppression and tumor promotion. Most, if not all, of the effects caused by TCDD and other PAHs are known to be mediated by AhR (aryl hydrocarbon receptor or dioxin receptor) which has a high binding affinity to TCDD. The liganded AhR translocates from cytoplasm to nuclei where it switches its partner molecule from Hsp90 to Arnt. Thus formed AhR/Arnt heterodimer binds a specific DNA sequence designated XRE in the promoter region of the target genes including CYP1A1, UDP-glucuronosyl transferase and others to enhance their expression. Although it remains to be studied how AhR is involved in the other TCDD-induced biological effects such as teratogenesis and immunosuppression than induction of XMEs, it is believed that these adverse TCDD effects are caused by untimely activation of gene expression by ligand-activated AhR in the biological process. We summarize the present knowledge about functional role of AhR in TCDD-induced biological effects.
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Affiliation(s)
- Junsei Mimura
- Department of Biomolecular Science, Graduate School of Life Science, Tohoku University, Aoba-ku, 980-8578, Sendai, Japan
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Abstract
Animals have evolved inducible enzymatic defenses to facilitate the biotransformation and elimination of toxic compounds encountered in the environment. The sensory component of this system consists of soluble receptors that regulate the expression of certain isoforms of cytochrome P450, other enzymes, and transporters in response to environmental chemicals. These receptors include several members of the steroid/nuclear receptor superfamily as well as the aryl hydrocarbon receptor (AHR), a member of the bHLH-PAS gene superfamily. In addition to its adaptive functions, the AHR serves poorly understood physiological roles; interference with those roles by dioxins and related chemicals causes toxicity. One approach to understanding the physiological significance of the AHR is to characterize its structure, function, and regulation in diverse species, including mammals, birds, fish, and invertebrates. These animal groups include model species with unique features that can be exploited to broaden our understanding of AHR function. Studies carried out in diverse species also provide phylogenetic information that allows inferences about the evolutionary history of the AHR. This review summarizes the current understanding of AHR diversity among animal species and the evolution of the AHR signaling pathway, as inferred from molecular studies in vertebrate and invertebrate animals. The AHR gene has undergone duplication and diversification in vertebrate animals, resulting in at least three members of an AHR gene family: AHR1, AHR2, and AHR repressor. The inability of invertebrate AHR homologs to bind dioxins and related chemicals, along with other evidence, suggests that the adaptive role of the AHR as a regulator of xenobiotic metabolizing enzymes may have been a vertebrate innovation. The physiological functions of the AHR during development appear to be ancestral to the adaptive functions. Sensitivity to the developmental toxicity of dioxins and related chemicals may have had its origin in the evolution of dioxin-binding capacity of the AHR in the vertebrate lineage.
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Affiliation(s)
- Mark E Hahn
- Biology Department, Woods Hole Oceanographic Institution, Redfield 340, MS 32, 45 Water Street, MA 02543-1049, USA.
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Abstract
The AH receptor (AHR) mediates toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) as well as induction of three cytochrome P450 enzymes and certain Phase II enzymes. In laboratory animals, genetic variations in the AHR lead to substantial differences in sensitivity to biochemical and toxic effects of TCDD and related compounds. Relatively few polymorphisms have been discovered in the human AHR gene; these occur predominantly in exon 10, a region that encodes a major portion of the transactivation domain of the receptor that is responsible for regulating expression of other genes. In human populations there is a wide range of variation in responses regulated by the AHR for example, induction of CYP1A1. Some variation in human responsiveness likely is due to genetically based variations in AHR structure. Thus far, however, only one pair of polymorphisms, those at codons 517 and 570, has been shown to have a clear cut and strong effect on the phenotype of an AHR-mediated response. The search continues for polymorphisms that alter AHR function because this receptor is a central factor in determining responses to important environmental contaminants and also plays a physiologic role in early development in mammals.
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Affiliation(s)
- Patricia A Harper
- Division of Clinical Pharmacology, Research Institute, The Hospital for Sick Children, 555 University Avenue, Toronto, ON, Canada M5G 1X8.
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Kim EY, Hahn ME. cDNA cloning and characterization of an aryl hydrocarbon receptor from the harbor seal (Phoca vitulina): a biomarker of dioxin susceptibility? AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2002; 58:57-73. [PMID: 12062155 DOI: 10.1016/s0166-445x(01)00221-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and related planar halogenated aromatic hydrocarbons (PHAHs) are found at high concentrations in some marine mammals. Species differences in sensitivity to TCDD and PHAHs are a major limitation in assessing the ecological risk to these animals. Harbor seals accumulate high levels of PHAHs and are thought to be highly sensitive to the toxic effects of these compounds. To investigate the mechanistic basis for PHAH toxicity in harbor seals (Phoca vitulina), we sought to characterize the aryl hydrocarbon receptor (AHR), an intracellular protein that is responsible for PHAH effects. Here we report the cDNA cloning and characterization of a harbor seal AHR. The harbor seal AHR cDNA has an open reading frame of 2529 nucleotides that encodes a protein of 843 amino acids with a predicted molecular mass of 94.6 kDa. The harbor seal AHR protein possesses basic helix-loop-helix (bHLH) and Per-ARNT-Sim (PAS) domains. It is most closely related to the beluga AHR (82%) and human AHR (79%) in overall amino acid identity, indicating a high degree of conservation of AHR structure between terrestrial and some marine mammals. The ligand binding properties of the harbor seal AHR were determined using protein synthesized by in vitro transcription and translation from the cloned cDNA. Velocity sedimentation analysis on sucrose gradients showed that the harbor seal AHR exhibits specific binding of [(3)H]TCDD. The [(3)H]TCDD-binding affinity of the harbor seal AHR was compared with that of the AHR from a dioxin-sensitive mouse strain (C57BL/6) using a hydroxylapatite assay. The equilibrium dissociation constants of seal and mouse AHRs were 0.93+/-0.19 and 1.70+/-0.26 nM, respectively. Thus, the harbor seal AHR bound TCDD with an affinity that was at least as high as that of the mouse AHR, suggesting that this seal species may be sensitive to PHAH effects. The characteristics of the AHR potentially can be used as a biomarker of susceptibility to dioxin-like compounds, contributing to the assessment of the risk of these compounds to marine mammals and other protected animals.
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Affiliation(s)
- Eun-Young Kim
- Biology Department, MS 32, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA
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Howard LA, Sellers EM, Tyndale RF. The role of pharmacogenetically-variable cytochrome P450 enzymes in drug abuse and dependence. Pharmacogenomics 2002; 3:185-99. [PMID: 11972441 DOI: 10.1517/14622416.3.2.185] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
Abstract
The risk of drug dependence is determined by the interaction of drug, individual and environment. 'Pharmacogenetics' is the study of the influence of heredity on the response to drugs and their fate in the body; these studies aim to improve the understanding of inter-individual variability in drug response. The authors have applied this research approach to the study of drug metabolism and dependence. Specifically the interaction of genetically variable hepatic cytochrome P450 (CYP) enzymes and their effect on self-administration of drugs has been examined. Many drugs of abuse are substrates (e.g., amphetamines, codeine, nicotine) or inhibitors (e.g., (-)-cocaine) of polymorphic CYPs. Drug metabolism by genetically polymorphic enzymes can have significant clinical implications relating to drug toxicity, therapeutic failure, drug-drug interactions, disease susceptibility and abuse liability. There is good evidence that drug metabolism by genetically variable CYPs can influence the risk of drug dependence, the amount of drug consumed by dependent individuals and some of the toxicities associated with drug-taking behavior. It is anticipated that pharmacogenetics will be used to identify individuals at a greater risk for specific drug dependencies, provide information that can lead to novel treatment and prevention approaches as well as provide guidance for individualization of treatment choice.
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Affiliation(s)
- Lisa A Howard
- Department of Pharmacology, University of Toronto, Toronto, Ontario, Canada, M5S 1A8
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Fujita H, Kosaki R, Yoshihashi H, Ogata T, Tomita M, Hasegawa T, Takahashi T, Matsuo N, Kosaki K. Characterization of the aryl hydrocarbon receptor repressor gene and association of its Pro185Ala polymorphism with micropenis. TERATOLOGY 2002; 65:10-8. [PMID: 11835227 DOI: 10.1002/tera.1093] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
BACKGROUND Genetic background of a fetus contributes to the abnormal development after teratogen exposure. In rodents, in utero exposure to dioxins affects male external genital development. The effects of dioxins are mediated via the aryl hydrocarbon receptor (AHR) and its binding protein, aryl hydrocarbon receptor nuclear translocator (ARNT). In mice, aryl hydrocarbon receptor repressor (AHRR), which binds to ARNT in competition with AHR, plays a critical negative regulatory role in AHR signaling. We attempt to characterize the human AHRR gene and investigate the relationship between AHRR polymorphisms and the incidence of micropenis, a phenotype of undermasculinization. METHODS We identified and characterized the human homolog of mouse AHRR, taking advantage of the publicly available draft version of the human genome sequence. After detecting an AHRR protein polymorphism by the direct sequencing of pooled human genomic DNA, we evaluated the association between the polymorphism and the presence or absence of micropenis (< -2.5 SD) in patients with micropenis and control subjects. RESULTS The deduced sequence for human AHRR (715 residues) and the mouse AHRR protein exhibited 81% sequence homology to each other. The Pro185Ala polymorphism was identified between the PAS-A region and the highly conserved arginine/cysteine-rich RCFRCRL/VRC region. Forty-six percent (27/59) of patients with micropenis and 27% (22/80) of the controls were homozygous for 185Pro; this difference in frequencies was significant (P = 0.03). CONCLUSIONS Homozygosity for the 185Pro allele of AHRR may increase the susceptibility of a fetus to the undermasculinizing effects of dioxin exposure in utero, presumably through the diminished inhibition of AHR-mediated signaling.
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Affiliation(s)
- Hideki Fujita
- Department of Pediatrics, Keio University School of Medicine, Tokyo, Japan
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Wong JM, Okey AB, Harper PA. Human aryl hydrocarbon receptor polymorphisms that result in loss of CYP1A1 induction. Biochem Biophys Res Commun 2001; 288:990-6. [PMID: 11689007 DOI: 10.1006/bbrc.2001.5861] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aryl hydrocarbon receptor (AHR) binds xenobiotic chemicals such as 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and regulates transcription of the P4501 subfamily that metabolizes many carcinogens. In humans, the most frequent polymorphism is R554L. We report here an additional two polymorphisms in AHR that show apparent linkage disequilibrium with the codon 554 polymorphism: the first is a previously described polymorphism, V570I; the second is a novel human AHR polymorphism, P571S. In vitro expression of these variant forms showed normal ligand binding and DNA binding activities. However, transient expression experiments revealed that the combined Ile(570) + Lys(554) variant failed to support TCDD-dependent induction of CYP1A1 expression. It is possible that the abrogation of CYP1A1 induction in the combined Lys(554) + Ile(570) variant may reduce susceptibility of the host to the carcinogenic effects of polycyclic aromatic hydrocarbons. This combination of variant genotypes is rare and appears to be confined primarily to persons of African descent.
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Affiliation(s)
- J M Wong
- Department of Pharmacology, University of Toronto, Toronto, Ontario, Canada
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