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Zhang Y, Shi Y, Tang J, Chen K, Wu M, Wu X, Qiu X. A transcriptomics-based analysis of mechanisms involved in the sex-dependent effects of diazepam on zebrafish. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2024; 275:107063. [PMID: 39191072 DOI: 10.1016/j.aquatox.2024.107063] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Revised: 08/07/2024] [Accepted: 08/22/2024] [Indexed: 08/29/2024]
Abstract
Diazepam (DZP) is a universally detected emerging pollutant in aquatic ecosystems. Although the sex-dependent effects of DZP on fish have been properly established, the underlying mechanisms remain unclear. In this study, zebrafish of both sexes were separately exposed to DZP (8 μg/L) for 21 days, and the alteration of the behaviors, brain amino acid neurotransmitter contents, and transcriptomic profiles were investigated. Although DZP exposure showed a sedative effect on both sexes, significantly reduced cumulative duration of high mobility and willingness to encounter the opposite sex were only observed in females. However, DZP significantly enhanced the brain levels of glutamate and glutamine in males but not in females. Transcriptome analysis identified more different expression genes (DEGs) in females (322 up-regulated and 311 down-regulated) than in males (138 up-regulated genes and 38 down-regulated). The DEGs in both sexes were significantly enriched in the KEGG (Kyoto Encyclopedia of Genes and Genomes) pathway of the synaptic vesicle cycle, indicating a possible pathway for the sedative effects of DZP on zebrafish. DZP exhibited different or even opposing regulatory patterns on gene expression in the brains of females and males, providing some insights into its sex-dependent impacts on the behaviors and brain neurotransmitter contents in zebrafish. Moreover, enrichment analysis also suggested that DZP exposure may affect the oocyte maturation in female zebrafish, which highlights the need to study its reproductive and transgenerational toxicity to fish species.
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Affiliation(s)
- Yibing Zhang
- College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Yanhong Shi
- College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Jie Tang
- College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Kun Chen
- College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China.
| | - Min Wu
- College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Xiangyang Wu
- College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China
| | - Xuchun Qiu
- College of Environment and Safety Engineering, Jiangsu University, Zhenjiang, Jiangsu 212013, China; Jiangsu Collaborative Innovation Center of Technology and Material of Water Treatment, Suzhou University of Science and Technology, Suzhou 215009, China.
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Jeanne PV, McLamb F, Feng Z, Griffin L, Gong S, Shea D, Szuch MA, Scott S, Gersberg RM, Bozinovic G. Locomotion and brain gene expression exhibit sex-specific non-monotonic dose-response to HFPO-DA during Drosophila melanogaster lifespan. Neurotoxicology 2023; 96:207-221. [PMID: 37156305 DOI: 10.1016/j.neuro.2023.05.005] [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: 02/16/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 05/10/2023]
Abstract
BACKGROUND Legacy per- and polyfluoroalkyl substances (PFAS), known for their environmental persistence and bio-accumulative properties, have been phased out in the U.S. due to public health concerns. A newer polymerization aid used in the manufacture of some fluoropolymers, hexafluoropropylene oxide-dimer acid (HFPO-DA), has lower reported bioaccumulation and toxicity, but is a potential neurotoxicant implicated in dopaminergic neurodegeneration. OBJECTIVE We investigated HFPO-DA's bio-accumulative potential and sex-specific effects on lifespan, locomotion, and brain gene expression in fruit flies. METHODS We quantified bioaccumulation of HFPO-DA in fruit flies exposed to 8.7×104µg/L of HFPO-DA in the fly media for 14 days via UHPLC-MS. Long-term effect on lifespan was determined by exposing both sexes to 8.7×102 - 8.7×105µg/L of HFPO-DA in media. Locomotion was measured following 3, 7, and 14 days of exposures at 8.7×101 - 8.7×105µg/L of HFPO-DA in media, and high-throughput 3'-end RNA-sequencing was used to quantify gene expression in fly brains across the same time points. RESULTS Bioaccumulation of HFPO-DA in fruit flies was not detected. HFPO-DA-induced effects on lifespan, locomotion, and brain gene expression, and lowest adverse effect level (LOAEL) showed sexually dimorphic patterns. Locomotion scores significantly decreased in at least one dose at all time points for females and only at 3-day exposure for males, while brain gene expression exhibited non-monotonic dose-response. Differentially expressed genes correlated to locomotion scores revealed sex-specific numbers of positively and negatively correlated genes per functional category. CONCLUSION Although HFPO-DA effects on locomotion and survival were significant at doses higher than the US EPA reference dose, the brain transcriptomic profiling reveals sex-specific changes and neurological molecular targets; gene enrichments highlight disproportionately affected categories, including immune response: female-specific co-upregulation suggests potential neuroinflammation. Consistent sex-specific exposure effects necessitate blocking for sex in experimental design during HFPO-DA risk assessment.
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Affiliation(s)
- P Vu Jeanne
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA; San Diego State University, Graduate School of Public Health, San Diego, CA, USA; University of California, San Diego, Division of Extended Studies, La Jolla, CA, USA
| | - Flannery McLamb
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA; University of California, San Diego, Division of Extended Studies, La Jolla, CA, USA
| | - Zuying Feng
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA; San Diego State University, Graduate School of Public Health, San Diego, CA, USA
| | - Lindsey Griffin
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA; University of California, San Diego, Division of Extended Studies, La Jolla, CA, USA
| | - Sylvia Gong
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA; San Diego State University, Graduate School of Public Health, San Diego, CA, USA; University of California, San Diego, Division of Extended Studies, La Jolla, CA, USA
| | | | - Mary A Szuch
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA
| | - Savannah Scott
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA
| | - Richard M Gersberg
- San Diego State University, Graduate School of Public Health, San Diego, CA, USA
| | - Goran Bozinovic
- Boz Life Science Research and Teaching Institute, San Diego, CA, USA; San Diego State University, Graduate School of Public Health, San Diego, CA, USA; University of California, San Diego, School of Biological Sciences, La Jolla, CA, USA.
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