Transcriptome analysis reveals the mechanism of fluorine exposure on memory loss of common carp

doi:10.1016/j.envpol.2020.114927

Environmental Pollution

Volume 265, Part A, October 2020, 114927

https://doi.org/10.1016/j.envpol.2020.114927 Get rights and content

Highlights

•
Fluorine could accumulate in brain tissues and lead to memory loss of common carp.
•
1186 genes in brain were differentially expressed in the fluorine-exposed carp.
•
Long-term depression and Ion channels were involved in fluorine-induced injury.

Abstract

Fluorine, an environmental toxicant in our daily life, has been reported to have adverse effects on nervous system. Previous studies demonstrated that fluorine exposure could induce brain injury in fish and human. However, the possible mechanism remains unclear. In the present study, we aimed to reveal the mechanism of fluorine exposure on brain injury of common carp through transcriptome analysis. In the fluorine-exposed carp, 444 brain genes were up-regulated, whereas 742 genes were down-regulated. DNA-templated (regulation of transcription) and multicellular organism development in the GO function annotation accounted for the most biological processes. Nucleus and membrane accounted for the most cellular components and DNA binding and metal ion binding accounted for the most molecular function. Meanwhile, 196 metabolic pathways were identified in Kyoto Encyclopedia of Genes and Genomes (KEGG) Pathway significant enrichment analysis, including long-term depression, Cushing syndrome, nuclear receptors, vascular smooth muscle contraction, Ion channels, and other pathways. Furthermore, we found that the up-regulated and down-regulated trends were similar between the quantitative real-time-PCR and RNA-Seq results, which indicate the transcriptome sequencing data is reliable. In conclusion, our data may provide insights into the mechanisms underlying brain injury induced by fluorine exposure.

Graphical abstract

Introduction

Fluorine, a common trace element in daily life, can enter into the body through breathing, eating and drinking (Adler et al., 2019; He et al., 2020). Under the condition of high fluorine environment, the excessive intake of fluoride in the body for a long time can make it widely accumulate in the body, which causes multiple organ damage and eventually lead to fluorosis (Aboal et al., 2008; Ullah et al., 2017). In many countries and regions around the world, the level of fluorine in lakes, rivers and other waters is higher than the standard value (Azizullah et al., 2011; Chen et al., 2017). The life activities of aquatic organisms such as fish are inseparable from the water environment. Therefore, fish are more vulnerable to fluorine pollution in the water (Camargo, 2003; Li et al., 2018). Through eating fish with high fluorine content, fluorine can be accumulated in the human body and resulted in fluorosis. Fluorosis is a serious public health problem that threatens the health of the people (Zhang et al., 2017). Therefore, it is an important task for us to explore the pathogenesis of fluorosis.

The accumulation of excessive fluoride in the body for a long time will lead to the symptoms of toxicological and pathological damage of various organs and tissues in the body, such as bone, liver, and kidney (Barbier et al., 2010; Wang et al., 2000). The effects of fluorosis on the central nervous system were also been concerned (Gui et al., 2010). Excessive fluoride can enter into brain tissue through the blood-brain barrier. After accumulation in brain tissue, it will cause abnormal apoptosis of glial cells and change of morphological structure and function of neurons, which will have adverse effects on nervous system (Dec et al., 2017). Fluorosis can affect a variety of physiological functions of the brain, such as the intellectual development of infants and children, and the learning and memory functions of children (Gui et al., 2010; Shao et al., 2000). Many epidemiological studies showed that long-term excessive intake of fluoride can cause brain damage, mental decline, impairment of learning and memory functions and behavior disorders (Lou et al., 2013). In fish, a large body of studies showed that fluorine could lead to the injury of kidney and liver tissues (Lu et al., 2010). Meanwhile, studies showed that exposure of fluorine could affect zebrafish behavior and induce brain injury (Mukhopadhyay et al., 2015). However, the mechanism underlying this remains unclear. Transcriptome analysis has been widely used in the animals, such as fish, chicken, and other animals (Wang et al., 2020; Zheng et al., 2020). In this study, we investigated the mechanism of fluorine exposure on brain injury and memory loss of common carp through transcriptome analysis and hope to provide valuable insight into the relationship of fluorine exposure and brain injury.

Section snippets

Reagents

Sodium fluoride (NaF) was purchased from Sigma-Aldrich (St. Louis, USA). SYBR Green Real-time PCR kit and TRIzol reagent were obtained from Takara (Dalian, China). The cDNA reverse transcription kit was purchased from Thermo (CA, USA).

Animals and treatment

Juvenile common carp (mean body weight, 56 ± 8 g) used in this study were obtained from the Xinli Reservoir (Changchun, China) and cultured in laboratory tanks (90 × 55 × 45 cm) with continuous aeration. After being acclimated and the temperature was adjusted to

Fluorineaccumulation in brain tissues

The accumulation of fluorine in brain tissues were measured in the present study. The levels of fluorine in brain tissues were listed in Fig. 1. The results showed that the levels of fluorine in brain tissues of fluorine exposed carps were much higher than the control carps. These results indicated fluorine was accumulated in brain tissues (Fig. 1).

Effects of fluorine exposure on memory loss

The effects of fluorine exposure on memory loss were tested in this study. As shown in Fig. 2, the carps of fluorine group used longer time to find

Discussion

Learning and memory is the advanced function of the brain (Yamada et al., 2002). It is a necessary process for animals to change their own behavior or produce new behavior in order to adapt to the living environment and make individual survival and ethnic continuity. In this study, we investigated the effects of fluorine exposure on brain injury and memory loss of common carp and clarify the possible mechanism through transcriptome analysis. Our results demonstrated that fluorine exposure to

Conclusions

In conclusion, our results reported a brain transcriptome of common carp exposed to fluorine. This provides an insightful view for the toxic effects of fluorine on brain tissue of common carp. A large number of genes that related to fluorine-induced injury were identified in this study. And the data showed that long-term depression, vascular smooth muscle contraction, and Ion channelswere related to fluorine exposure-induced brain injury in common carp.

Declaration of competing interest

All authors declare that they have no conflict of interest.

Acknowledgement

The work was supported by the National Natural Science Foundation of China (no.30972191), Jilin Province Industrial Technology Research and Development Special Project (no.2019C059-5) and Jilin Province Science and Technology Development Plan Project (no.20190201179JC).

References (40)

J.R. Aboal et al.
Physiological responses to atmospheric fluorine pollution in transplants of Pseudoscleropodium purum
Environ. Pollut.
(2008)
A. Azizullah et al.
Water pollution in Pakistan and its impact on public health--a review
Environ. Int.
(2011)
O. Barbier et al.
Molecular mechanisms of fluoride toxicity
Chem. Biol. Interact.
(2010)
J.A. Camargo
Fluoride toxicity to aquatic organisms: a review
Chemosphere
(2003)
J. Cao et al.
Tissue distributions of fluoride and its toxicity in the gills of a freshwater teleost, Cyprinus carpio
Aquat. Toxicol.
(2013)
J. Cao et al.
Protective properties of sesamin against fluoride-induced oxidative stress and apoptosis in kidney of carp (Cyprinus carpio) via JNK signaling pathway
Aquat. Toxicol.
(2015)
H. Chen et al.
Occurrence and seasonal variations of per- and polyfluoroalkyl substances (PFASs) including fluorinated alternatives in rivers, drain outlets and the receiving Bohai Sea of China
Environ. Pollut.
(2017)
S. Fujii
ATP- and adenosine-mediated signaling in the central nervous system: the role of extracellular ATP in hippocampal long-term potentiation
J. Pharmacol. Sci.
(2004)
Y. Fukata et al.
Rho-Rho-kinase pathway in smooth muscle contraction and cytoskeletal reorganization of non-muscle cells
Trends Pharmacol. Sci.
(2001)
M. Gomez et al.
Ca2+ signaling via the neuronal calcium sensor-1 regulates associative learning and memory in C. elegans
Neuron
(2001)

C.Z. Gui et al.

Changes of learning and memory ability and brain nicotinic receptors of rat offspring with coal burning fluorosis

Neurotoxicol. Teratol.

(2010)

T. Houtani et al.

Cloning and expression of ligand-gated ion-channel receptor L2 in central nervous system

Biochem. Biophys. Res. Commun.

(2005)

D. Li et al.

Diverse mechanisms drive fluoride enrichment in groundwater in two neighboring sites in northern China

Environ. Pollut.

(2018)

Y.G. Long et al.

Chronic fluoride toxicity decreases the number of nicotinic acetylcholine receptors in rat brain

Neurotoxicol. Teratol.

(2002)

P.V. Massey et al.

Long-term depression: multiple forms and implications for brain function

Trends Neurosci.

(2007)

D. Mukhopadhyay et al.

Sodium fluoride affects zebrafish behaviour and alters mRNA expressions of biomarker genes in the brain: role of Nrf2/Keap1

Environ. Toxicol. Pharmacol.

(2015)

F. Rao et al.

Involvement of Src in L-type Ca2+ channel depression induced by macrophage migration inhibitory factor in atrial myocytes

J. Mol. Cell. Cardiol.

(2009)

L. Valdez-Jimenez et al.

Effects of the fluoride on the central nervous system

Neurologia

(2011)

W. Wang et al.

Ammonia regulates chicken tracheal cell necroptosis via the LncRNA-107053293/MiR-148a-3p/FAF1 axis

J. Hazard Mater.

(2020)

Y.N. Wang et al.

Effect of long term fluoride exposure on lipid composition in rat liver

Toxicology

(2000)

Cited by (6)

Transcriptome analysis reveals the mechanism of the effect of perfluorocaproic acid exposure on brain injury in Carassius auratus
2023, Aquatic Toxicology
Perfluorocaproic acid (PFHxA) has received much attention as an emerging pollutant linked to neurological problems in humans and fish. However, the potential mechanism remains unknown. In this study, the pathological damage to tissue sections demonstrated that perfluorocaproic acid caused brain tissue damage, and the increased antioxidant index malondialdehyde (MDA) and decrease in superoxide Dismutase (SOD), acid phosphatase (ACP), alkaline phosphatase (AKP), glutathione peroxidase (GSH-Px), Catalase (CAT), and Lysozyme (LZM) that perfluorocaproic acid activated antioxidant stress and caused brain damage. Transcriptome sequencing discovered 1,532 divergent genes, 931 upregulated, and 601 down-regulated. Furthermore, according to GO enrichment analysis, the differently expressed genes were shown to be involved in biological processes, cellular components, and molecular functions. The MAPK, calcium, and Neuroactive ligand-receptor interaction were considerably enriched in the KEGG enrichment analysis. We then analyzed qRT-PCR and chose ten essential differentially expressed genes for validation. The qRT-PCR results followed the same pattern as the RNA-Seq results. In conclusion, our study shows that perfluorocaproic acid exposure causes oxidative stress in the brain. It establishes a theoretical foundation for future research into genes linked to perfluorocaproic acid toxicity.
Toxicity of herbicide glyphosate to planarian Dugesia japonica and its potential molecular mechanisms
2023, Aquatic Toxicology
Glyphosate (GLY) is one of the most widely used agrochemicals in the world, and its exposure has become a public health concern. The freshwater planarian is an ideal test organism for detecting the toxicity of pollutants and has been an emerging animal model in toxicological studies. Nevertheless, the underlying toxicity mechanism of GLY to planarians has not been thoroughly explored. To elucidate the toxicity effects and molecular mechanism involved in GLY exposure of planarians, we studied the acute toxicity, histological change, and transcriptional response of Dugesia japonica subjected to GLY. Significant morphological malformations and histopathological changes were observed in planarians after GLY exposure for different times. Also, a number of differentially expressed genes (DEGs) were obtained at 1, 3 and 5 d after exposure; Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis of these DEGs were performed, and a global and dynamic view was obtained in planarians upon GLY exposure at the transcriptomic level. Furthermore, real-time quantitative PCR (qRT-PCR) was conducted on nine DEGs associated with detoxification, apoptosis, stress response, DNA repair, etc. The expression patterns were well consistent with the RNA sequencing (RNA-seq) results at different time points, which confirmed the reliability and accuracy of the transcriptome data. Collectively, our results established that GLY could pose adverse effects on the morphology and histo-architecture of D. japonica, and the planarians are capable of responding to the disadvantageous stress by dysregulating the related genes and pathways concerning immune response, detoxification, energy metabolism, DNA damage repair, etc. To the best of our knowledge, this is the first report of transcriptomic analyses of freshwater planarians exposed to environmental pollutants, and it provided detailed sequencing data deriving from transcriptome profiling to deepen our understanding the molecular toxicity mechanism of GLY to planarians.
Acute damage from the degradation of Ulva prolifera on the environmental microbiota, intestinal microbiota and transcriptome of Japanese flounder Paralichthys olivaceus
2022, Environmental Pollution
Citation Excerpt :
Tissue sections as a routine experimental method, can provide direct view of biological damage and are widely used in assessing biological damage from environmental pollutants (Pang et al., 2021; von Moos et al., 2012). Transcriptome sequencing is also a conventional method for studying environmental pollutants which can provide evidence of alteration of gene expression caused by pollutants, providing insight into physiological impacts on fish (Jia et al., 2021; Pang et al., 2021; Zhang et al., 2020). In this study, a suite of sophisticated techniques was designed to assess the effects on environmental microbiota, fish intestinal microbiota and transcriptome of Japanese flounder with exposure to fresh U. prolifera and the decomposition effluent of U. prolifera.
Green tide outbreaks caused by overgrowth of Ulva prolifera in the Yellow Sea of China can cause serious ecological stress with concomitant economic hardships, especially to marine fisheries. In this study, short-term effects (14 days) were evaluated using fresh algae U. prolifera (FU), and a 7-day assessment of the effects of decomposing U. prolifera (DU) algal effluent was conducted to determine the effects on the environmental and intestinal microbiota, intestinal transcriptome and mortality of the commercial marine benthic fish, Japanese flounder (Paralichthys olivaceus). The results revealed that algal degradation altered the microbial community structure of fish farm water and fish intestines and increased the relative abundance of the pathogens Flavobacteriaceae in water and Vibrio in fish intestines. Fish intestinal tissue structure appeared to be damaged, as indicated in pathological sections, and transcriptome analysis showed intestinal inflammation after exposure, which may have caused an increase in fish mortality. The degradation of U. prolifera led to a bloom of potential pathogenic bacteria and the inflammation of fish intestines, which resulted in disease in the flounder population that reduced fish harvests and might pose a potential health threat.
Mechanistic revealing of reproductive behavior impairment in male guppy (Poecilia reticulata) induced by environmentally realistic 2,2′-dithiobis-pyridine exposure
2022, Chemosphere
Citation Excerpt :
After excluding the possible roles of secondary sexual characteristics and estrogenic activity, the implication of CNS is anticipated to play an essential role in the reproductive behavior weakening regulation. In recent years, using brain transcriptome to disclose the underlying biological mechanisms of differential behavioral phenotypes in fish resulting from aquatic pollutant exposure has been drawing increasing interest (Porseryd et al., 2017; Porseryd, 2018; Suzuki et al., 2020; Zhang et al., 2020; Chen et al., 2021). As the first study demonstrating that transcriptome-wide changes were associated with the reproductive behavior of fish, Saaristo et al. (2021) utilizing whole-brain transcriptome examined the impact of 17α-ethinylestradiol at an environmentally relevant concentration of 8 ng/L on reproductive behavior in guppies.
Although (PS)₂, the primary degradation product of emerging antifouling biocides metal pyrithiones (MePTs), can disrupt the reproductive behavior of fish at an environmentally relevant ng/L level, the underlying mechanism is still largely unknown. This study exposed sexually mature male guppy (Poecilia reticulata) to 20, 200, and 2000 ng/L (PS)₂ to explore the compromised effect of (PS)₂ on reproductive behavior through a realistic competing scenario. The results showed that (PS)₂ suppressed male guppies' sexual interest to stimulus females, reduced their competitive behavior frequencies toward rival males, and decreased their mating time and frequency. (PS)₂ exposure did not affect male guppies' secondary sexual characteristics or induce estrogenic activity. Whole-brain transcriptome sequencing identified 1070 differentially expressed genes (DEGs) with 872 up-regulated genes, which were functionally enriched into Gene Ontology terms pertaining to extracellular matrix (ECM) and extracellular region. KEGG enrichment for the DEGs uncovered that the activations of ECM-receptor interaction and focal adhesion pathways could be the underlying molecular mechanism implicated in the (PS)₂ induced reproductive behavior impairment. This work would deliver a substantial contribution to the understanding of the ecological safety of MePTs biocides.
Transcriptome analysis reveals the mechanism of alkalinity exposure on spleen oxidative stress, inflammation and immune function of Luciobarbus capito
2021, Ecotoxicology and Environmental Safety
Citation Excerpt :
Next, the RNA nano 6000 detection kit of the Bioanalyzer 2100 system (Agilent Technology, CA, USA) was used to analyze the integrity of the RNA. A cDNA strand with 6 random base primers was synthesized using mRNA as a template (Zhang et al., 2020). Then, add buffer, dNTP, DNA polymerase I to synthesize the second strand of cDNA.
Saline-alkali land is distributed all over the world, and it affects the economic development of fisheries. The alkalinity in water is related to the accumulation of carbonate, so the is generally higher. To understand how alkalinity impacts the immune response in Luciobarbus capito, we performed transcriptomic profiles for spleen, the immune organ of Luciobarbus capito which were underwent alkalinity exposure. Totally there are 47,727,954, 53,987,820 and 51,398,546 high quality clean reads obtained from the control groups, and 46,996,982, 49,650,460 and 45,964,986 clean reads from the alkalinity exposure groups. Among them, 611 genes were differently expressed, including 534 upregulated and 77 down-regulated genes. The identified genes were enriched using databases of Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). It was found that differentially expressed genes in Luciobarbus capito spleen tissue were enriched into 14 GO pathways, and differentially expressed genes in Luciobarbus capito spleen were enriched into 25 corresponding KEGG pathways under alkalinity stress. Inflammation and immune function genes and pathways were identified and validated by quantitative real-time RT-PCR. Our results showed that alkalinity exposure leads to inflammation and immunoregulation in spleen of Luciobarbus capito. These results provide new insights for unveiling the biological effects of alkalinity in Luciobarbus capito.
Development of a carbazole-based fluorescent probe for quantitative detection of fluoride ions in aqueous systems
2023, Chemical Papers

^☆: This paper has been recommended for acceptance by Sarah Harmon.

View full text

Transcriptome analysis reveals the mechanism of fluorine exposure on memory loss of common carp☆

Highlights

Abstract

Graphical abstract

Introduction

Section snippets

Reagents

Animals and treatment

Fluorineaccumulation in brain tissues

Effects of fluorine exposure on memory loss

Discussion

Conclusions

Declaration of competing interest

Acknowledgement

Environ. Pollut.

Environ. Int.

Chem. Biol. Interact.

Chemosphere

Aquat. Toxicol.

Aquat. Toxicol.

Environ. Pollut.

J. Pharmacol. Sci.

Trends Pharmacol. Sci.

Neuron

Neurotoxicol. Teratol.

Biochem. Biophys. Res. Commun.

Environ. Pollut.

Neurotoxicol. Teratol.

Trends Neurosci.

Environ. Toxicol. Pharmacol.

J. Mol. Cell. Cardiol.

Neurologia

J. Hazard Mater.

Toxicology