The physiology of males and females can be vastly different, complicating interpretation of toxicological and physiological data. The objectives of this study were to elucidate the sex differences in the microbiome-gastrointestinal (GI) transcriptome of adult zebrafish. We compared microbial composition and diversity in both males and females fed the same diet and housed in the same environment. There were no sex-specific differences in weight gain nor gastrointestinal morphology based on histopathology. There was no difference in gut microbial diversity, richness (Shannon and Chao1 index) nor predicted functional composition of the microbiome between males and females. Prior to post-hoc correction, male zebrafish showed higher abundance for the bacterial families Erythrobacteraceae and Lamiaceae, both belonging to the phyla Actinobacteria and Proteobacteria. At the genus level, Lamia and Altererythrobacter were more dominant in males and an unidentified genus in Bacteroidetes was more abundant in females. There were 16 unique differentially expressed transcripts in the gastrointestinal tissue between male and female zebrafish (FDR corrected, p < 0.05). Relative to males, the mRNA expression for trim35-9, slc25a48, chchd3b, csad, and hsd17b3 were lower in female GI while cyp2k6, adra2c, and bckdk were higher in the female GI. Immune and lipid-related gene network expression differed between the sexes (i.e., cholesterol export and metabolism) as well as networks related to gastric motility, gastrointestinal system absorption and digestion. Such data provide clues as to putative differences in gastrointestinal physiology between male and female zebrafish. This study identifies host-transcriptome differences that can be considered when interpreting the microgenderome of zebrafish in studies investigating GI physiology and toxicology of fishes.
The phenylpyrazole fipronil is an insecticide that inhibits γ -amino-butyric acid (GABA) ionotropic receptors in the central nervous system. Experimental evidence suggests that fipronil acts as a neurotoxin and it is implicated in neurodegenerative diseases; however, the mechanisms of neurotoxicity are not fully elucidated. The objective of this study was to quantify mechanisms of fipronil-induced neurotoxicity in dopamine cells. Rat primary immortalized mesencephalic dopaminergic cells (N27) were treated with fipronil (0.25 up to 500 μM depending on the assay). We measured endpoints related to mitochondrial bioenergetics, mitophagy, mitochondrial membrane potential, and ATP production in addition to discerning transcriptome responses to the pesticide. Fipronil reduced cell viability at 500 μM after 24 h exposure and caspase 3/7 activity was significant increased after 6 and 12 h by 250 and 500 μM fipronil. Subsequent endpoints were thus assessed at concentrations that were below cytotoxicity. We measured oxidative respiration of N27 cells following a 24 h exposure to one dose of either 0.25, 2.5, 25, or 50 μM fipronil. Oxygen consumption rates (OCR) were not different between vehicle-control and 0.25 or 2.5 μM fipronil treatments, but there was a ∼40-60 % reduction in basal respiration, as well as reduced oligomycin-induced ATP production at 50 μM. The reduction in OCR is hypothesized to be related to lower mitochondrial mass due to mitophagy. Mitochondrial membrane potential was also sensitive to fipronil, and it was compromised at concentrations of 2.5 μM and above. To further elucidate the mechanisms linked to neurotoxicity, we conducted transcriptomics in dopamine cells following treatment with 25 μM fipronil. Fipronil suppressed transcriptional networks associated with mitochondria (damage, depolarization, permeability, and fission), consistent with its effects on mitochondrial membrane potential. Altered gene networks also included those related to Alzheimer disease, inflammatory disease, nerve fiber degeneration, and neurofibrillary tangles. This study clarifies molecular targets of fipronil-induced neurotoxicity and supports, through multiple lines of evidence, that fipronil acts as a mitochondrial toxicant in dopamine cells. This is relevant to neurodegenerative diseases like Parkinson's disease as exposure to fipronil is associated with the progressive loss of nigrostriatal dopaminergic neurons in rodents.
- MeSH
- dopaminergní neurony účinky léků metabolismus MeSH
- insekticidy toxicita MeSH
- krysa rodu rattus MeSH
- membránový potenciál mitochondrií účinky léků fyziologie MeSH
- mitochondrie účinky léků metabolismus MeSH
- pyrazoly toxicita MeSH
- transformované buněčné linie MeSH
- transkriptom účinky léků fyziologie MeSH
- viabilita buněk účinky léků fyziologie MeSH
- vztah mezi dávkou a účinkem léčiva MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Water contaminated with plastic debris and leached plasticizers can be ingested or taken up by aquatic invertebrates and vertebrates alike, exerting adverse effects on multiple tissues including the gastrointestinal tract. As such, gut microbiomes of aquatic animals are susceptible targets for toxicity. Recent studies conducted in teleost fishes report that microplastics and plasticizers (e.g., phthalates, bisphenol A) induce gastrointestinal dysbiosis and alter microbial diversity in the gastrointestinal system. Here we synthesize the current state of the science regarding plastics, plasticizers, and their effects on microbiomes of fish. Literature suggests that microplastics and plasticizers increase the abundance of opportunistic pathogenic microorganisms (e.g. Actinobacillus, Mycoplasma and Stenotrophomonas) in fish and reveal that gamma-proteobacteria are sensitive to microplastics. Recommendations moving forward for the research field include (1) environmentally relevant exposures to improve understanding of the long-term impacts of microplastic and plasticizer contamination on the fish gastrointestinal microbiome; (2) investigation into the potential impacts of understudied polymers such as polypropylene, polyamide and polyester, and (3) studies with elastomers such as rubbers that are components of tire materials, as these chemicals often dominate plastic debris. Focus on both microplastics and the gut microbiota is intensifying in environmental toxicology, and herein lies an opportunity to improve evaluation of global ecological impacts associated with plastic contamination. This is important as the microbiota is intimately tied to an individual's health and fragmentation of microbial community networks and gut dysbiosis can result in disease susceptibility and early mortality events.
- MeSH
- chemické látky znečišťující vodu toxicita MeSH
- ekotoxikologie * MeSH
- mikroplasty toxicita MeSH
- monitorování životního prostředí MeSH
- ryby růst a vývoj mikrobiologie MeSH
- střevní mikroflóra * MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
To improve physical characteristics of plastics such as flexibility and durability, producers enrich materials with phthalates such as di-2-(ethylhexyl) phthalate (DEHP). DEHP is a high production volume chemical associated with metabolic and immune disruption in animals and humans. To reveal mechanisms implicated in phthalate-related disruption in the gastrointestinal system, male and female zebrafish were fed DEHP (3 ppm) daily for two months. At the transcriptome level, DEHP significantly upregulated gene networks in the intestine associated with helper T cells' (Th1, Th2, and Th17) specific pathways. The activation of gene networks associated with adaptive immunity was linked to the suppression of networks for tight junction, gap junctional intercellular communication, and transmembrane transporters, all of which are precursors for impaired gut integrity and performance. On a class level, DEHP exposure increased Bacteroidia and Gammaproteobacteria and decreased Verrucomicrobiae in both the male and female gastrointestinal system. Further, in males there was a relative increase in Fusobacteriia and Betaproteobacteria and a relative decrease in Saccharibacteria. Predictive algorithms revealed that the functional shift in the microbiome community, and the metabolites they produce, act to modulate intestinal adaptive immunity. This finding suggests that the gut microbiota may contribute to the adverse effects of DEHP on the host by altering metabolites sensed by both intestinal and immune Th cells. Our results suggest that the microbiome-gut-immune axis can be modified by DEHP and emphasize the value of multiomics approaches to study microbiome-host interactions following chemical perturbations.
- MeSH
- adaptivní imunita MeSH
- dánio pruhované MeSH
- diethylhexylftalát * MeSH
- kyseliny ftalové * MeSH
- lidé MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
