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. 2022 Mar 18;23(6):3286.
doi: 10.3390/ijms23063286.

Molecular Mechanism Based on Histopathology, Antioxidant System and Transcriptomic Profiles in Heat Stress Response in the Gills of Japanese Flounder

Weijie Yan  1 , Yingjie Qiao  1 , Jiayi He  1 , Jiangbo Qu  1 , Yuxiang Liu  1 , Quanqi Zhang  1 , Xubo Wang  1
Affiliations

Molecular Mechanism Based on Histopathology, Antioxidant System and Transcriptomic Profiles in Heat Stress Response in the Gills of Japanese Flounder

Weijie Yan et al. Int J Mol Sci. .

Abstract

As an economically important flatfish in Asia, Japanese flounder is threatened by continuously rising temperatures due to global warming. To understand the molecular responses of this species to temperature stress, adult Japanese flounder individuals were treated with two kinds of heat stress-a gradual temperature rise (GTR) and an abrupt temperature rise (ATR)-in aquaria under experimental conditions. Changes in histopathology, programmed cell death levels and the oxidative stress status of gills were investigated. Histopathology showed that the damage caused by ATR stress was more serious. TUNEL signals confirmed this result, showing more programmed cell death in the ATR group. In addition, reactive oxygen species (ROS) levels and the 8-O-hDG contents of both the GTR and ATR groups increased significantly, and the total superoxide dismutase (T-SOD) activities and total antioxidant capacity (T-AOC) levels decreased in the two stressed groups, which showed damage to antioxidant systems. Meanwhile, RNA-seq was utilized to illustrate the molecular mechanisms underyling gill damage. Compared to the control group of 18 °C, 507 differentially expressed genes (DEGs) were screened in the GTR group; 341 were up-regulated and 166 were down-regulated, and pathway enrichment analysis indicated that they were involved in regulation and adaptation, including chaperone and folding catalyst pathways, the mitogen-activated protein kinase signaling (MAPK) pathway and DNA replication protein pathways. After ATR stress, 1070 DEGs were identified, 627 were up-regulated and 423 were down-regulated, and most DEGs were involved in chaperone and folding catalyst and DNA-related pathways, such as DNA replication proteins and nucleotide excision repair. The annotation of DEGs showed the great importance of heat shock proteins (HSPs) in protecting Japanese flounder from heat stress injury; 12 hsp genes were found after GTR, while 5 hsp genes were found after ATR. In summary, our study records gill dysfunction after heat stress, with different response patterns observed in the two experimental designs; chaperones were activated to defend heat stress after GTR, while replication was almost abandoned due to the severe damage consequent on ATR stress.

Keywords: Japanese flounder; gill; heat stress; oxidative stress.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
Effect of heat stress on gills of Japanese flounder. GTR, Gradual Temperature Rise; ATR, Abrupt Temperature Rise.
Figure 2
Figure 2
Effect of heat stress on antioxidant system and DNA damage product in the gills of Japanese flounder under two kinds of heat stress. Subfigure (a–d) represents ROS content, T-SOD activity, the level of T-AOC and 8-O-hDG content, respectively. One asterisk represents significant differences (p < 0.05) while two asterisks represent extremely significant differences (p < 0.01) between the control group and an experimental group.
Figure 3
Figure 3
Programmed cell death evaluated by TUNEL (terminal deoxynucleotidyl transferase deoxy-UTP nick end labeling) and DAPI (4′,6-diamidino-2-phenylindole) after heat stress. C, Control; GTR, Gradual Temperature Rise; ATR, Abrupt Temperature Rise.
Figure 4
Figure 4
Volcano plot of DEGs after GTR and ATR. Every dot represents one gene; the red dots represent significantly up-regulated genes, the blue dots represent significantly down-regulated genes and the grey dots represent genes which have not reached the differential expression level.
Figure 5
Figure 5
The visualized results of GSEA. The up-regulated pathways after GTR (A) are as follows: Chaperones and folding catalysts (M03110), G protein-coupled receptors (M04030), Ion channels (M04040), Protein processing in endoplasmic reticulum (M04141), Cardiac muscle contraction (M04260), Adrenergic signaling in cardiomyocytes (M04261), Cytoskeleton proteins (M04812). The down-regulated pathways after GTR (B) are as follows: Steroid biosynthesis (M00100), Ribosome biogenesis (M03009), DNA replication (M03030), DNA replication proteins (M03032), Spliceosome (M03040), DNA repair and recombination proteins (M03400), Base excision repair (M03410). The up-regulated pathways after ATR (C) are as follows: Chaperones and folding catalysts (M03110), Neuroactive ligand–receptor interaction (M04080). The down-regulated pathways after ATR (D) are as follows: RNA transport (M03013), DNA replication (M03030), DNA replication proteins (M03032), Base excision repair (M03410), Nucleotide excision repair (M03420), Cytokine receptors (M04050), Cell cycle (M04110).
Figure 6
Figure 6
The response of the mitogen-activated protein kinase signaling (MAPK) pathway after two kinds of heat stress. Note: The blue bar represents the GTR while the red bar represents ATR; the up-regulated genes are above the line while the down-regulated genes are below the line.
Figure 7
Figure 7
Expression profiles of hsp (heat shock protein) 10/20/40/60/70 genes after heat stress. Each cell in the heat map corresponds to an expression level.
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References

    1. Gracey A.Y., Fraser E.J., Li W., Fang Y., Taylor R.R., Rogers J., Brass A., Cossins A.R. Coping with cold: An integrative, multitissue analysis of the transcriptome of a poikilothermic vertebrate. Proc. Natl. Acad. Sci. USA. 2004;101:16970–16975. doi: 10.1073/pnas.0403627101. - DOI - PMC - PubMed
    1. Bagnyukova T., Lushchak O., Storey K.B., Lushchak V. Oxidative stress and antioxidant defense responses by goldfish tissues to acute change of temperature from 3 to 23 C. J. Therm. Biol. 2007;32:227–234. doi: 10.1016/j.jtherbio.2007.01.004. - DOI
    1. López-Olmeda J., Sánchez-Vázquez F. Thermal biology of zebrafish (Danio rerio) J. Therm. Biol. 2011;36:91–104. doi: 10.1016/j.jtherbio.2010.12.005. - DOI
    1. Lee S., Ji K., Choi K. Effects of water temperature on perchlorate toxicity to the thyroid and reproductive system of Oryzias latipes. Ecotoxicol. Environ. Saf. 2014;108:311–317. doi: 10.1016/j.ecoenv.2014.07.016. - DOI - PubMed
    1. Sudo R., Tosaka R., Ijiri S., Adachi S., Suetake H., Suzuki Y., Horie N., Tanaka S., Aoyama J., Tsukamoto K. Effect of temperature decrease on oocyte development, sex steroids, and gonadotropin β-subunit mRNA expression levels in female Japanese eel Anguilla japonica. Fish. Sci. 2011;77:575–582. doi: 10.1007/s12562-011-0358-3. - DOI