Identification of aryl hydrocarbon receptor signaling pathways altered in TCDD-treated red seabream embryos by transcriptome analysis.
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) induces a broad spectrum of toxic effects including craniofacial malformation and neural damage in fish embryos. These effects are mainly mediated by the aryl hydrocarbon receptor (AHR). However, the mode of action between TCDD-induced AHR activation and adverse outcomes is not yet understood. To provide a comprehensive picture of the AHR signaling pathway in fish embryos exposed to TCDD, red seabream (Pagrus major) embryos were treated with graded concentrations of TCDD (0.3-37nM) in seawater, or with a mixture of TCDD and 500nM CH223191, an AHR-specific antagonist. The transcriptome of red seabream embryos was analyzed using a custom-made microarray with 6000 probes specifically prepared for this species. A Jonckheere-Terpstra test was performed to screen for genes that demonstrated altered mRNA expression levels following TCDD exposure. The signals of 1217 genes (as human homologs) were significantly altered in a TCDD concentration-dependent manner (q-value<0.2). Notably, the TCDD-induced alteration in mRNA expression was alleviated by co-exposure to CH223191, suggesting that the mRNA expression level of these genes was regulated by AHR. To identify TCDD-activated pathways, the microarray data were further subjected to gene set enrichment analysis (GSEA) and functional protein-protein interaction (PPI) network analysis. GSEA demonstrated that the effects of TCDD on sets of genes involved calcium, mitogen-activated protein kinase (MAPK), actin cytoskeleton, chemokine, T cell receptor, melanoma, vascular endothelial growth factor (VEGF), axon guidance, and renal cell carcinoma signaling pathways. These results suggest the hypotheses that TCDD induces immunosuppression via the calcium, MAPK, chemokine, and T cell receptor signaling pathways, neurotoxicity via VEGF signaling, and axon guidance alterations and teratogenicity via the dysregulation of the actin cytoskeleton and melanoma and renal cell carcinoma signaling pathways. Furthermore, the PPI network analysis indicated that the adverse outcome pathways of TCDD in the embryos might be propagated through several hub genes such as cell division control protein 42, phosphoinositide-3-kinase regulatory subunit 1, and guanine nucleotide-binding proteins. Understanding these pathways potentially allows for exploring the adverse outcome pathway of the effects of TCDD on the red seabream embryos.
Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, 790-8577, Japan; Computer Science and Systems Engineering, Kyusyu Institute of Technology, Iizuka, 820-0067, Japan. Electronic address: redgreen@bio.kyutech.ac.jp.
Midori
M
Iida
Computer Science and Systems Engineering, Kyusyu Institute of Technology, Iizuka, 820-0067, Japan. Electronic address: sfujii@bio.kyutech.ac.jp.
Satoshi
S
Fujii
Mizuki biotech. co., ltd, Kurume, 839-0864, Japan. Electronic address: uchida@mizuki-bio.co.jp.
Masaya
M
Uchida
Mizuki biotech. co., ltd, Kurume, 839-0864, Japan. Electronic address: ocean@mizuki-bio.co.jp.
Hiroshi
H
Nakamura
Mizuki biotech. co., ltd, Kurume, 839-0864, Japan. Electronic address: kagami@mizuki-bio.co.jp.
Yoshihiro
Y
Kagami
Graduate School of Environmental and Symbiotic Sciences, Prefectural University of Kumamoto, Kumamoto, 862-0920, Japan. Electronic address: te-agusa@pu-kumamoto.ac.jp.
Tetsuro
T
Agusa
Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, 790-8577, Japan. Electronic address: m-hirano@agr.ehime-u.ac.jp.
Masashi
M
Hirano
Department of Life and Nanopharmaceutical Science and Department of Biology, Kyung Hee University, Seoul, 130-701, Korea. Electronic address: ladyofkorea@naver.com.
Su-Min
SM
Bak
Department of Life and Nanopharmaceutical Science and Department of Biology, Kyung Hee University, Seoul, 130-701, Korea. Electronic address: eykim08@khu.ac.kr.
Eun-Young
EY
Kim
Center for Marine Environmental Studies (CMES), Ehime University, Matsuyama, 790-8577, Japan. Electronic address: iwatah@agr.ehime-u.ac.jp.
Hisato
H
Iwata
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D020411:Oligonucleotide Array Sequence Analysis; D000072317:Polychlorinated Dibenzodioxins / Q000633:toxicity*; D018336:Receptors, Aryl Hydrocarbon / Q000378:metabolism*; D021541:Sea Bream / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects*; D018675:Toxicity Tests; D059467:Transcriptome / Q000187:drug effects*; D014874:Water Pollutants, Chemical / Q000633:toxicity*
D015415:Biomarkers; D000072317:Polychlorinated Dibenzodioxins; D018336:Receptors, Aryl Hydrocarbon; D014874:Water Pollutants, Chemical
Gene set enrichment analysis; Microarray; Red seabream; TCDD; Transcriptome