Tu Jing, Wu Shengping, Wang Lingjie, Meng Chi, Zhou Gengxu, Guo Jianhua, Li Jixiang, Cao Liting, Song Zhenhui, Jiao Hanwei
The College of Veterinary Medicine, Southwest University, Chongqing 402460, China.
Vet Sci. 2025 Sep 19;12(9):912. doi: 10.3390/vetsci12090912.
(1) Background: Hepatitis E (HE) is a novel zoonotic disease caused by hepatitis E virus (HEV). In particular, swine hepatitis E virus (SHEV) genotype IV is one of the main genotypes that infect humans. Open reading frame 3 (ORF3) is an important virulence protein of SHEV, which is involved in virus assembly, release, and regulation of host cell signaling pathways. Circular RNAs (circRNAs), as a type of competitive endogenous RNA (ceRNA), have a closed-loop structure and are special non-coding RNA molecules. They participates in the regulation of multiple biological processes by adsorbing microRNAs (miRNAs). Riboflavin, also known as vitamin B2, is a component of the coenzyme of flavoenzymes in the body. When there is a deficiency of riboflavin, it will affect the biological oxidation process of the host, leading to metabolic disorders. In addition, riboflavin can also affect the synthesis, transportation and decomposition of lipids in the body. It mainly maintains the normal transportation process of fat in the liver. Therefore, the deficiency of riboflavin will lead to the disorder of lipid metabolism in the body. Thus, viral hepatitis is closely related to riboflavin metabolism. However, there are very few reports on SHEV ORF3 affecting the riboflavin metabolism of target cells and thereby influencing viral infection. Therefore, this study investigates this highly significant scientific issue. (2) Methods: In the previous research of our group, adenovirus was used to mediate the overexpression of SHEV ORF3 genotype IV in HepG2 cells. Total RNA was extracted for high-throughput sequencing of circRNAs and transcriptome. KEGG functional enrichment analysis was performed on the data to identify the differentially expressed circRNAs and miRNAs after SHEV infection, and the relevant circRNA-miRNA network in the riboflavin metabolism pathway in HepG2 cells was found. (3) Results: We identified 4 circRNAs in the riboflavin metabolism pathway of HepG2 cells expressing the ORF3 protein of SHEV genotype IV and successfully found 26 relevant circRNA-miRNA networks. (4) Conclusion: We successfully screened and identified circRNAs related to riboflavin metabolism, further identifying the circRNA-miRNA network and its functional targets. For the first time, we investigated the key mechanism by which ORF3 protein influences riboflavin metabolic pathways in target cells through circRNAs, preliminarily revealing that ariboflavinosis can lead to lipid metabolic disorder in the organism. This indicates a close association between viral HE and riboflavin metabolism.
（1）背景：戊型肝炎（HE）是一种由戊型肝炎病毒（HEV）引起的新型人畜共患病。特别是，猪戊型肝炎病毒（SHEV）基因IV型是感染人类的主要基因型之一。开放阅读框3（ORF3）是SHEV的一种重要毒力蛋白，参与病毒组装、释放以及宿主细胞信号通路的调节。环状RNA（circRNA）作为一种竞争性内源性RNA（ceRNA），具有闭环结构，是特殊的非编码RNA分子。它们通过吸附微小RNA（miRNA）参与多种生物学过程的调节。核黄素，也称为维生素B2，是体内黄素酶辅酶的组成成分。当核黄素缺乏时，会影响宿主的生物氧化过程，导致代谢紊乱。此外，核黄素还会影响体内脂质的合成、运输和分解。它主要维持肝脏中脂肪的正常运输过程。因此，核黄素缺乏会导致体内脂质代谢紊乱。由此可见，病毒性肝炎与核黄素代谢密切相关。然而，关于SHEV ORF3影响靶细胞核黄素代谢从而影响病毒感染的报道极少。因此，本研究对这一极具意义的科学问题展开调查。（2）方法：在本课题组之前的研究中，利用腺病毒介导SHEV基因IV型的ORF3在HepG2细胞中过表达。提取总RNA用于circRNA和转录组的高通量测序。对数据进行KEGG功能富集分析，以鉴定SHEV感染后差异表达的circRNA和miRNA，并发现HepG2细胞中核黄素代谢途径中的相关circRNA-miRNA网络。（3）结果：我们在表达SHEV基因IV型ORF3蛋白的HepG2细胞的核黄素代谢途径中鉴定出4种circRNA，并成功发现26个相关的circRNA-miRNA网络。（4）结论：我们成功筛选并鉴定出与核黄素代谢相关的circRNA，进一步明确了circRNA-miRNA网络及其功能靶点。我们首次研究了ORF3蛋白通过circRNA影响靶细胞核黄素代谢途径的关键机制，初步揭示核黄素缺乏症可导致机体脂质代谢紊乱。这表明病毒性戊型肝炎与核黄素代谢密切相关。
