The canonical Wnt/β-catenin signaling pathway facilitates pseudorabies virus proliferation and enhances virus-induced autophagy

Natural small molecule compounds targeting Wnt signaling pathway inhibit HPV infection

BACKGROUND

High-risk human papillomavirus (HPV) infection is a major risk factor of HPV-related tumors, especially cervical cancer. To date, there is no specific drug for the treatment of HPV infection.

PURPOSE

To explore the role of canonical Wnt signaling pathway in HPV16 infection and to screen inhibitors against HPV16 infection from natural small molecule compounds targeting the canonicalWnt pathway.

METHODS

Wnt pathway inhibitor IWP-2 and FH535 were used to inhibit Wnt/β-catenin signaling pathway. HPV16-GFP pseudovirus infectivity were analyzed by fluorescence microscopy and fluorescence activated cell sorting. A small molecule screening of a total of CFDA-approved 29 natural compounds targeting the Wnt pathway was performed.

RESULTS

Wnt signaling pathway inhibitor suppressed HPV16-GFP pseudovirus infection in HaCat cells. Natural small molecule compounds screening identified 6-Gingerol, gossypol, tanshinone II2A, and EGCG as inhibitors of HPV16-GFP pseudovirus infection.

CONCLUSION

Wnt signaling pathway is involved in the process of HPV infection of host cells. 6-Gingerol, gossypol, tanshinone II2A, and EGCG inhibited HPV16-GFP pseudovirus infection and suppressed Wnt/β-catenin pathway in HaCat cells.

Identification of porcine PARP11 as a restricted factor for pseudorabies virus

Introduction

PRV infection in swine can cause devastating disease and pose a potential threat to humans. Advancing the interplay between PRV and host is essential to elucidate the pathogenic mechanism of PRV and identify novel anti-PRV targets.

Methods

PARP11-KO PK-15 cells were firstly constructed by CRISPR/Cas9 technology. Next, the effect of PARP11-KO on PRV infection was determined by RT-qPCR, TCID50 assay, RNA-seq, and western blot.

Results and discussion

In this study, we identified PARP11 as a host factor that can significantly affect PRV infection. Inhibition of PARP11 and knockout of PARP11 can significantly promoted PRV infection. Subsequently, we further found that PARP11 knockout upregulated the transcription of NXF1 and CRM1, resulting in enhanced transcription of viral genes. Furthermore, we also found that PARP11 knockout could activate the autophagy pathway and suppress the mTOR pathway during PRV infection. These findings could provide insight into the mechanism in which PARP11 participated during PRV infection and offer a potential target to develop anti-PRV therapies.

Wnt3a Facilitates SARS-CoV-2 Pseudovirus Entry into Cells

How ACE2 functions as the major host receptor of SARS-CoV-2 despite having low expression in the lungs is still unknown. To facilitate the development of therapeutic strategies against coronaviruses, gaining a deeper comprehension of the molecular mechanism of SARS-CoV-2 infection is imperative. In our previous study, we identified several potential host factors of SARS-CoV-2 using an shRNA arrayed screen, one of which was Wnt3a. Here, we validated the significance of Wnt3a, a potent activator of the Wnt/β-catenin signaling pathway, for SARS-CoV-2 entry into cells by evaluating the effects of its knockdown and overexpression on SARS-CoV-2 pseudotyped virus entry. Further analysis revealed that SARS-CoV-2 pseudotyped virus infection activates the canonical Wnt/β-catenin signaling pathway, which we found could subsequently stimulate ACE2 transcription. Collectively, our study identified Wnt3a as an important host factor that facilitates ACE2-mediated virus infection. Insight into the virus entry mechanism is impactful as it will aid in developing novel therapeutic strategies against current and future coronavirus pandemics.

Seneca Valley Virus Degrades STING via PERK and ATF6-Mediated Reticulophagy

Seneca Valley Virus (SVV), a member of the Picornaviridae family, is an emerging porcine virus that can cause vesicular disease in pigs. However, the immune evasion mechanism of SVV remains unclear, as does its interaction with other pathways. STING (Stimulator of interferon genes) is typically recognized as a critical factor in innate immune responses to DNA virus infection, but its role during SVV infection remains poorly understood. In the present study, we observed that STING was degraded in SVV-infected PK-15 cells, and SVV replication in the cells was affected when STING was knockdown or overexpressed. The STING degradation observed was blocked when the SVV-induced autophagy was inhibited by using autophagy inhibitors (Chloroquine, Bafilomycin A1) or knockdown of autophagy related gene 5 (ATG5), suggesting that SVV-induced autophagy is responsible for STING degradation. Furthermore, the STING degradation was inhibited when reticulophagy regulator 1 (FAM134B), a reticulophagy related receptor, was knocked down, indicating that SVV infection induces STING degradation via reticulophagy. Further study showed that in eukaryotic translation initiation factor 2 alpha kinase 3 (PERK)/activating transcription factor 6 (ATF6) deficient cells, SVV infection failed to induce reticulophagy-medaited STING degradation, indicating that SVV infection caused STING degradation via PERK/ATF6-mediated reticulophagy. Notably, blocking reticulophagy effectively hindered SVV replication. Overall, our study suggested that SVV infection resulted in STING degradation via PERK and ATF6-mediated reticulophagy, which may be an immune escape strategy of SVV. This finding improves the understanding of the intricate interplay between viruses and their hosts and provides a novel strategy for the development of novel antiviral drugs.

gga-miR-20b-5p inhibits infectious bursal disease virus replication via targeting Netrin 4

MicroRNAs (miRNAs) involved host-virus interaction, affecting the replication or pathogenesis of several viruses. Frontier evidences suggested that miRNAs play essential roles in infectious bursal disease virus (IBDV) replication. However, the biological function of miRNAs and the underlying molecular mechanisms are still unclear. Here, we reported that gga-miR-20b-5p acted as a negative factor affecting IBDV infection. We found that gga-miR-20b-5p was significantly up-regulated during IBDV infection in host cells, and that gga-miR-20b-5p effectively inhibited IBDV replication via targeting the expression of host protein netrin 4 (NTN4). In contrast, inhibition of endogenous miR-20b-5p markedly facilitated viral replication associated with enhancing NTN4 expression. Collectively, these findings highlight a crucial role of gga-miR-20b-5p in IBDV replication.

A bivalent β-carboline derivative inhibits macropinocytosis-dependent entry of pseudorabies virus by targeting the kinase DYRK1A

Pseudorabies virus (PRV) has become a "new life-threatening zoonosis" since the human-originated PRV strain was first isolated in 2020. To identify novel anti-PRV agents, we screened a total of 107 β-carboline derivatives and found 20 compounds displaying antiviral activity against PRV. Among them, 14 compounds showed better antiviral activity than acyclovir. We found that compound 45 exhibited the strongest anti-PRV activity with an IC₅₀ value of less than 40 nM. Our in vivo studies showed that treatment with 45 significantly reduced the viral loads and protected mice challenged with PRV. To clarify the mode of action of 45, we conducted a time of addition assay, an adsorption assay, and an entry assay. Our results indicated that 45 neither had a virucidal effect nor affected viral adsorption while significantly inhibiting PRV entry. Using the FITC-dextran uptake assay, we determined that 45 inhibits macropinocytosis. The actin-dependent plasma membrane protrusion, which is important for macropinocytosis, was also suppressed by 45. Further, the kinase DYRK1A was predicted to be a potential target for 45. The binding of 45 to DYRK1A was confirmed by DARTS and CETSA. Further analysis revealed that knockdown of DYRK1A by siRNA suppressed PRV macropinocytosis and the TNFα-induced formation of protrusions. These results suggested that 45 could restrain PRV macropinocytosis by targeting DYRK1A. Together, these findings reveal a unique mechanism through which β-carboline derivatives restrain PRV infection, pointing to their potential value in the development of anti-PRV agents. Our data also reveal a potential target for designing novel macropinocytosis inhibitors.

Progress on innate immune evasion and live attenuated vaccine of pseudorabies virus

Pseudorabies virus (PRV) is a highly infectious disease that can infect most mammals, with pigs as the only natural host, has caused considerable economic losses to the pig husbandry of the world. Innate immunity is the first defense line of the host against the attack of pathogens and is essential for the proper establishment of adaptive immunity. The host uses the innate immune response to against the invasion of PRV; however PRV makes use of various strategies to inhibit the innate immunity to promote the virus replication. Currently, live attenuated vaccine is used to prevent pig from infection with the PRV worldwide, such as Bartha K61. However, a growing number of data indicates that these vaccines do not provide complete protection against new PRV variants that have emerged since late 2011. Here we summarized the interactions between PRV and host innate immunity and the current status of live attenuated PRV vaccines to promote the development of novel and more effective PRV vaccines.