Hepatitis E (Hepatitis E, HE) is an acute and chronic infectious hepatitis caused by hepatitis E virus (Hepatitis E Virus, HEV) infection, which is responsible for most acute hepatitis in the world and is a significant public health problem. The pathogen, HEV, has three Open Reading Frames (ORFs) ORF1, ORF2, and ORF3, each of which has a different function. Most of the current research is focused on ORF1 and ORF2, while the research on ORF3 is still relatively small. To provide more ideas for the study of HEV pathogenesis and the prevention and treatment of HE, this paper reviews the effects of ORF3 on the ERK pathway, growth factors, immune response, and virus release.

Brucellosis is a severe zoonotic disease caused by Brucella infection, which remains prevalent in several regions worldwide and poses a significant public health challenge. The host deploys complex immune mechanisms to combat the pathogen, including the recognition of pathogenic signals, secretion of inflammatory factors, and activation of innate and adaptive immune responses. Brucella, as a facultative intracellular pathogen, replicates within host cells and establishes chronic infections through diverse immune evasion strategies. These include subversion of Toll-like receptor (TLR) signaling, disruption of antigen presentation, and interference with T cell responses. This review focuses on Brucella species with significant human infectivity, such as B. melitensis and B. abortus, summarizing their interactions with the host immune system. Recent studies have highlighted TLR pathway inhibition, antigen presentation impairment, and T cell dysregulation as key mechanisms of immune evasion. Understanding these processes is crucial for elucidating Brucella pathogenesis and developing novel therapeutic and vaccine strategies against brucellosis.

Background: Swine hepatitis E (HEV) is a zoonotic infectious disease caused by the swine hepatitis E virus (SHEV). Open reading frame 3 (ORF3) is a key virulence factor in swine HEV, playing a crucial role in the release of viral particles, the modulation of the host innate immune response, and regulation of autophagy and apoptosis, etc. However, its main function and pathogenic mechanism remain incompletely understood. Results: In our study, adenoviruses ADV4-ORF3 and ADV4-GFP were successfully constructed and mediated the overexpression of enhanced green fluorescent protein (EGFP)-ORF3 and EGFP in HepG2 cells. A total of 217 differentially expressed messenger RNAs (mRNAs) were screened by high-throughput sequencing, and 27 statistically significant differentially expressed genes were screened for further quantitative real-time reverse transcription (qRT-PCR) verification by functional enrichment (Gene Ontology [GO] and Kyoto Encyclopedia of Genes and Genomes [KEGG]). They are mainly involved in six pathways: the cellular response to unfolded protein, inflammatory response, cytokine activity, TNF signaling pathway, influenza A, and pathways in cancer. In a comparative analysis of transcriptome and mRNA expression profiles of lncRNA sequencing, the results showed that 3 mRNAs of GPX1, MDM4, and CLDN and 39 transcripts overlapped and have been identified. Conclusions: Eight differential genes, HSPA1A, HSPA1B, PLD3, RELA, GPI, SAMHD1, RPS6KA4, and PIK3CB, were successfully verified. Comparing and analyzing the results of the two sequencing methods indicated that the 3 mRNAs of GPX1, MDM4, and CLDN and 39 transcripts overlapped and have been identified in SHEV ORF3-expressing HepG2 cells, which has laid a genetic foundation for the physiological function and mechanism of SHEV ORF3.

The Swine hepatitis E virus (SHEV) ORF3 protein is pivotal in pathogenesis, yet its regulation of host metabolic homeostasis via endogenous RNA networks remains unclear. This study aimed to elucidate how the SHEV ORF3-mediated circRNA-miRNA network modulates riboflavin metabolism and triggers the aberrant activation of the ko05212 pathway, while also evaluating their physical interactions using AlphaFold 3 structural simulations. To achieve this, high-throughput RNA sequencing, KEGG pathway analysis, and AlphaFold 3 structural simulations were employed to elucidate the circRNA-miRNA-mRNA regulatory network and potential physical interactions. Transcriptomics revealed a “dual activation” of Riboflavin metabolism and Pancreatic cancer pathways. Specifically, we identified an “ENPP Isozyme Switch,” where upregulated hsa_circ_0077855 sponges miR-181a-2-3p, relieving repression of the metabolic enzyme ENPP3 and proto-oncogene KRAS. Furthermore, AlphaFold 3 simulations yielded an extremely low interface predicted Template Modeling score (ipTM = 0.08), refuting direct physical binding, and ORF3 was found to suppress the m6A eraser FTO, suggesting host epigenetic instability. Consequently, SHEV ORF3 induces metabolic remodeling through a dual “epigenetic-post-transcriptional” mechanism: disrupting m6A homeostasis via FTO suppression and constructing a pathogenic ceRNA network via the ENPP3/miR-181a/KRAS axis. These findings highlight the critical role of non-coding RNAs in driving the virus-induced “pre-pathological state”.

(1) Background: Swine hepatitis E (SHE) is an emerging zoonotic disease caused by the swine hepatitis E virus (SHEV). The open reading frame 3 (ORF3) protein is a recognized virulence factor of SHEV. Jaundice, the typical clinical sign of SHE, primarily results from disruptions in bile production, secretion, and excretion. However, the mechanism by which SHEV ORF3 influences bile metabolism remains unclear. (2) Methods: Building on our previous work involving adenovirus-mediated overexpression of genotype IV SHEV ORF3 in HepG2 cells and subsequent high-throughput lncRNA/transcriptome sequencing, this study performed KEGG enrichment analysis on differentially expressed lncRNAs. Candidate lncRNAs were validated via qRT-PCR. Cis-regulated target genes were predicted by integrating differentially expressed mRNA data. Furthermore, AlphaFold 3.0 was employed to analyze the molecular binding sites between lncRNA UBC (MSTRG.6881.4) and its target, UBC protein. (3) Results: We identified three lncRNAs associated with the bile secretion pathway (ko 04976) in HepG2 cells expressing genotype IV SHEV ORF3, which were further confirmed by qRT-PCR: lncRNA UBC (MSTRG.6881.4), lncRNA UBC (MSTRG.6881.9), and lncRNA UBC (MSTRG.6881.12). Bioinformatics prediction suggested six lncRNA-mRNA regulatory networks involved these lncRNAs and two downregulated UBC mRNA transcripts (ENST00000540700 and ENST00000536769). Molecular docking indicated that nucleotides 395U and 41C of lncRNA UBC (MSTRG.6881.4) could potentially bind to residues 82Lys, 88Thr, and 90Thr of the UBC protein, with predicted binding energies ranging from −4.73 to −0.75 kcal/mol. (4) Conclusions: The successful identification of bile secretion-related lncRNAs, coupled with the prediction of their regulatory networks and molecular interaction sites, has advanced our understanding of SHEV ORF3 function and the pathogenesis of SHEV infection.

Hepatitis E virus (HEV) is one of the pathogens that cause viral hepatitis, and its clinical symptoms can manifest as acute, chronic viral hepatitis, or asymptomatic infection. Among them, swines are the main animal source of HEV. Open reading frame 3 (ORF3) is a multifunctional protein essential for swine hepatitis E virus (SHEV) infection and release, involved in biological processes such as intracellular signal transduction regulation. In our preliminary research, we utilized adenovirus-mediated overexpression of type IV SHEV ORF3 in HepG2 cells, extracted total RNA, and performed high-throughput long non coding RNAs (lncRNAs) and transcriptome sequencing. In this study, we screened and analyzed lncRNAs involved in the GO pathway: viral process (GO: 0016032), and combined them with differentially expressed mRNAs for target gene prediction. We identified two lncRNAs—lncRNA AL137002 (MSTRG. 7478) and lncRNA AL049840 (MSTRG. 8427)—that are associated with viral progression and have p ≤ 0.05 in HepG2 cells expressing ORF3 of porcine hepatitis E virus type IV. We predicted their five lncRNA-mRNA networks, which are lncRNA AL137002 (MSTRG. 7478)-ENST0000375440, lncRNA AL137002 (MSTRG. 7478)-ENST0000375441, lncRNA AL049840(MSTRG. 8427)-ENST0000246489, lncRNA AL049840 (MSTRG. 8427)-ENST0000554280 and lncRNA AL049840 (MSTRG. 8427)-ENST0000452929, and were used to predict their lncRNA mRNA binding sites and construct relevant molecular models. This will lay a solid foundation for further revealing the function of SHEV ORF3 and elucidating the mechanism of SHEV infection.