Long Noncoding RNA Expression Rofiles Elucidate the Potential Roles of lncRNA- XR_003496198 in Duck Hepatitis A Virus Type 1 Infection

Advances in the Duck Hepatitis A virus and lessons learned from those in recent years

Duckviral hepatitis (DVH) is a highly lethal and highly transmissible viral infectious disease of ducklings caused by the Duck Hepatitis A virus (DHAV), which is characterized by clinical neurological symptoms and liver enlargement with spot-like hemorrhages. In recent years, the change in diagnosis, prevention, and control of the disease has brought great challenges due to the mutation and recombination of epidemic strains, outbreaks and epidemics of genotype 3 (DHAV-3), and the rising trend of mixed infections. Here, we review DHAV on aspects of molecular biological characteristics, epidemiology, pathologic changes, pathogenesis, diagnosis, prevention, and control of the DVH to provide a scientific basis for basic and applied research in the future.

Up-regulated Lnc BTU promotes the production of duck plague virus DNA polymerase and inhibits the activation of JAK-STAT pathway to facilitate duck plague virus replication

Duck plague virus (DPV) is the only herpes virus known to be transmissible among aquatic animals, leading to immunosuppression in ducks, geese and swans. Long noncoding RNAs (LncRNA) are known to participate in viral infections, acting as either immune defenders or viral targets to evade the host response, but their precise roles in waterfowl virus infections are yet to be fully understood. This study aimed to investigate the role of LncRNA in DPV-induced innate immune responses. Results showed that DPV infection greatly upregulated Lnc BTU expression in duck embryo fibroblasts (DEF) and Lnc BTU promoted DPV replication. Mechanically, 4 DPV proteins, namely UL46, UL42, VP22 and US10, interacted with Lnc BTU, leading to its upregulation. Specifically, Lnc BTU facilitated the production of DNA polymerase by enhancing UL42 expression, thereby promoting DPV replication. Additionally, Lnc BTU suppressed STAT1 expression by targeting the DNA binding domain (DBD) and promoting STAT1 degradation through the proteasome pathway. Furthermore, Lnc BTU inhibited the production of key antiviral factors such as IFN-α, IFN-β, MX and OASL during DPV infection. Treatment with 2 JAK-STAT pathway activators in DEFs resulted in the inhibition of Lnc BTU expression and DPV replication. Interestingly, DPV infection led to a decrease in STAT1 levels, which was reversed by Si-Lnc BTU. These findings suggest that DPV relies on Lnc BTU to inhibit the activation of the JAK-STAT pathway and limit the production of type 1 interferons (IFN) to complete immune evasion. Our study highlights the novel role of DPV proteins UL46, UL42, VP22, US10 as RNA-binding proteins in modulating the innate antiviral immune response, and discover the role of a new host factor, Lnc BTU, in DPV immune evasion, Lnc BTU and STAT1 can be used as a potential therapeutic target for DPV infection and immune evasion.

mRNA and miRNA expression profiles reveal the potential roles of RLRs signaling pathway and mitophagy in duck hepatitis A virus type 1 infection

Duck hepatitis A virus 1 (DHAV-1) is the primary cause of duck viral hepatitis, leading to sudden mortality in ducklings and significant economic losses in the duck industry. However, little is known about how DHAV-1 affects duckling liver at the molecular level. We conducted an analysis comparing the expression patterns of mRNAs and miRNAs in DHAV-1-infected duckling livers to understand the underlying mechanisms and dynamic changes. We identified 6,818 differentially expressed mRNAs (DEGs) and 144 differentially expressed microRNAs (DEMs) during DHAV-1 infection. Functional enrichment analysis of DEGs and miRNA target genes using gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) revealed their potential involvement in innate antiviral immunity, mitophagy, and pyroptosis. We constructed coexpression networks of mRNA-miRNA interactions and confirmed key DEMs (novel-mir333, novel-mir288, novel-mir197, and novel-mir71) using RT-qPCR. Further investigation demonstrated that DHAV-1 activates the RLRs signaling pathway, disrupts mitophagy, and induces pyroptosis. In conclusion, DHAV-1-induced antiviral immunity is closely linked to mitophagy, suggesting it could be a promising therapeutic target.

Current status and future direction of duck hepatitis A virus vaccines

Duck viral hepatitis (DVH), mainly caused by duck hepatitis A virus (DHAV), is a highly fatal and rapidly spreading infectious disease of young ducklings that seriously jeopardizes the duck industry worldwide. DHAV type 1 (DHAV-1) is the main genotype responsible for disease outbreaks since 1945, and the disease situation is complicated by the emergence and dissemination of a novel genotype (DHAV-3) in some countries in Asia and Africa. Live attenuated DHAV vaccines are widely used to induce a considerable degree of protection in ducklings. Breeder ducks are immunized with inactivated or/and live DHAV vaccines to achieve satisfactory levels of passive immunity in progeny. In addition, novel characteristics of virus transmission, pathogenicity and pathogenesis of DHAV were recently characterized, necessitating the development of new vaccines and effective vaccination programmes against DVH. Therefore, a systematic dissection of the profiles, strengths and shortcomings of the available DHAV vaccines is essential. Moreover, to further increase the efficiency of vaccine production and administration, the development of next-generation DHAV vaccines using cutting-edge technologies is also required. In this review, based on a comprehensive summary of the research advances in the epidemiology, pathogenicity, and genomic features of DHAV, we focus on reviewing and analysing the features of the commercial and experimental DHAV vaccines. We also propose perspectives for disease control based on the specific disease situations in different countries. This review provides essential information for vaccine development and disease control of DVH.

RNA-seq and microRNA association analysis to explore the pathogenic mechanism of DHAV-1 infection with DEHs

Duck hepatitis A virus 1 (DHAV-1) is one of the main contagious pathogens that causes rapid death of ducklings. To illuminate the potential of DHAV-1-infected underlying mechanisms, we analyzed the mRNA and microRNA (miRNA) expression profiles of duck embryonic hepatocytes (DEHs) in response to DHAV-1. We found 3410 differentially expressed genes (DEGs) and 142 differentially expressed miRNAs (DEMs) at 36 h after DHAV-1 infection. Additionally, DEGs and the target genes of miRNA expression were analyzed and enriched utilizing GO and KEGG, which may be crucial for immune responses, viral resistance, and mitophagy. For instance, the dysregulation of DDX58, DHX58, IRF7, IFIH1, STING1, TRAF3, CALCOCO2, OPTN, PINK1, and MFN2 in DHAV-1-infected DEHs was verified by RT-qPCR. Then, the association analysis of mRNAs and miRNAs was constructed utilizing the protein-protein interaction (PPI) networks, and the expressions of main miRNAs were confirmed, including miR-132c-3p, miR-6542-3p, and novel-mir163. These findings reveal a synthetic characterization of the mRNA and miRNA in DHAV-1-infected DEHs and advance the understanding of molecular mechanism in DHAV-1 infection, which may provide a hint for the interactions of virus and host.

A proposed disease classification system for duck viral hepatitis

The nomenclature of duck viral hepatitis (DVH) was historically not a problem. However, 14 hepatotropic viruses among 10 different genera are associated with the same disease name, DVH. Therefore, the disease name increasingly lacks clarity and may no longer fit the scientific description of the disease. Because one disease should not be attributed to 10 genera of viruses, this almost certainly causes misunderstanding regarding the disease-virus relationship. Herein, we revisited the problem and proposed an update to DVH disease classification. This classification is based on the nomenclature of human viral hepatitis and the key principle of Koch's postulates (“one microbe and one disease”). In total, 10 types of disease names have been proposed. These names were literately matched with hepatitis-related viruses. We envision that this intuitive nomenclature system will facilitate scientific communication and consistent interpretation in this field, especially in the Asian veterinary community, where these diseases are most commonly reported.