Male mice exposed to chronic intermittent ethanol exposure exhibit significant upregulation or downregulation of circular RNAs

ABSTRACT

B a ckground: Circular RNAs (circRNAs) have been crucially implicated in various diseases, however, their involvement in chronic intermittent ethanol (CIE) exposure remains unclear.

O bjective: The present study was conducted to evaluate the circular RNA expression alteration in brain samples and to identify the molecular mechanisms underlying chronic intermittent ethanol exposure.

M ethods: Male C57BL/6J mice (10 for each group) were given 4 weeks of chronic intermittent ethanol exposure. Whole brain samples were collected for high-throughput sequencing and circRNA bioinformatic analysis. Real-time quantitative PCR (RI-qPCR) and agarose electrophoresis were used to validate the differentially expressed circRNAs. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) analysis were performed. A p level < 0.05 was considered statistically significant.

R esults: Compared with the control group and baseline values, the CIE group showed a significant increase in ethanol intake. High-throughput sequencing revealed 399 significantly different circRNAs in CIE mice, including 150 up-regulated circRNAs and 249 down-regulated circRNAs. GO analysis showed that the most significantly enriched term for biological process, cellular component, and molecular function were GO:0050885, GO:0016020 and GO:0005515, respectively. The most enriched pathways in KEGG analysis were GABAergic synapse (mmu04727), followed by retrograde endocannabinoid (eCB) signaling (mmu04723) and morphine addiction (mmu05032). Among the circRNAs, RT-qPCR confirmed 14 upregulated and 13 downregulated circRNAs in the brain tissues with 9 upregulated and 10 downregulated circRNAs being observed in blood samples.

C onclusions: Our study suggests that chronic ethanol exposure upregulates or downregulates circRNAs in the brain, which, in turn, could alter neurotransmitter release and signal transduction.

KEYWORDS:

• Circular RNAs
• chronic intermittent ethanol exposure
• gene ontology
• bioinformatics
• biomarkers

Disclosure statement

No potential conflict of interest was reported by the author(s).

Contributors

YP and XMR designed the experiment, whereas GZ and XMR executed the experiments. XPL, DDL, HXW, QYS and LH assisted in date review and in the preparation of the manuscript. All authors read and commented on the manuscript, and approved its final version.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00952990.2022.2073449.

Additional information

Funding

This research was supported by the National Key R&D Program of China [2018YFC1314400, 2018YFC1314401] to Ying Peng, the National Natural Science Foundation of China [82001290] and Medical Science and Technology project of Henan Province [LHGJ20190085] to Zhe Gong.