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(1) Background: Porcine Parvovirus (PPV) is a single-stranded DNA virus without envelope which causes great harm in relation to porcine reproductive disorders in clinic. Cluster of Differentiation 38 (CD38) is a transmembrane protein widely existing in mammals. Its various functions make it a very popular research object, including in the viral infection field. (2) Methods: Western blotting and an EdU Cell Proliferation Kit were used to evaluate the effect of CD38-deficient cells. Relative quantitative real-time RT-PCR was used to detect the transcription levels of cytokines after PPV infection. The renilla luciferase reporter gene assay was used to verify the activation function of CD38 on downstream factors. The fluorescence probe method was used to detect the level of intracellular reactive oxygen species (ROS). (3) Results: This study found that the loss of CD38 function inhibited the up-regulated state of Toll-like Receptor 9 (TLR9), Interferon-α (IFN-α), and Myxovirus Resistance 1 (Mx1) after PPV infection. The luminescence of the group transfected with both CD38 expression plasmid and TLR9 promoter renilla luciferase reporter plasmid was significantly up-regulated compared with the control, suggesting that CD38 may activate the promoter of TLR9. In addition, CD38 deficiency not only activated the transcription of Sirtuin-1 (SIRT1), but also inhibited ROS level and the transcription of NLR Family Pyrin Domain Containing 3 (NLRP3). (4) Conclusion: (i) CD38 may participate in the TLR9/IFN-α/Mx1 pathway by activating the expression of TLR9 after PPV infected PK-15 cells; (ii) CD38 may activate the NLRP3/CASP1 pathway by increasing ROS level; (iii) CD38 deficiency activates the expression of SIRT1 and can prevent the normal proliferation of PPV.

Transmission from an infected mosquito to a host is an essential process in the life cycle of mosquito-borne flaviviruses. Numerous studies have demonstrated that mosquito saliva facilitates viral transmission. Here we find that a saliva-specific protein, named Aedes aegypti venom allergen-1 (AaVA-1), promotes dengue and Zika virus transmission by activating autophagy in host immune cells of the monocyte lineage. The AG6 mice (ifnar1–/–ifngr1–/–) bitten by the virus-infected AaVA-1-deficient mosquitoes present a lower viremia and prolonged survival. AaVA-1 intracellularly interacts with a dominant negative binder of Beclin-1, known as leucine-rich pentatricopeptide repeat-containing protein (LRPPRC), and releases Beclin-1 from LRPPRC-mediated sequestration, thereby enabling the initialization of downstream autophagic signaling. A deficiency in Beclin-1 reduces viral infection in mice and abolishes AaVA-1-mediated enhancement of ZIKV transmission by mosquitoes. Our study provides a mechanistic insight into saliva-aided viral transmission and could offer a potential prophylactic target for reducing flavivirus transmission., Mosquito saliva affects transmission of flaviviruses, but underlying mechanisms are incompletely understood. Here, the authors show that Aedes aegypti venom allergen-1 (AaVA-1) promotes dengue and Zika virus transmission by activating autophagy in host immune cells of the monocyte lineage.

PDCoV is an emerging enteropathogenic coronavirus that mainly causes acute diarrhea in piglets, seriously affecting pig breeding industries worldwide. To date, the molecular mechanisms of PDCoV-induced immune and inflammatory responses or host responses in LLC-PK cells in vitro are not well understood. HSP90 plays important roles in various viral infections. In this study, HSP90AB1 knockout cells (HSP90AB1KO) were constructed and a comparative transcriptomic analysis between PDCoV-infected HSP90AB1WT and HSP90AB1KO cells was conducted using RNA sequencing to explore the effect of HSP90AB1 on PDCoV infection. A total of 1295 and 3746 differentially expressed genes (DEGs) were identified in PDCoV-infected HSP90AB1WT and HSP90AB1KO cells, respectively. Moreover, most of the significantly enriched pathways were related to immune and inflammatory response-associated pathways upon PDCoV infection. The DEGs enriched in NF-κB pathways were specifically detected in HSP90AB1WT cells, and NF-κB inhibitors JSH-23, SC75741 and QNZ treatment reduced PDCoV infection. Further research revealed most cytokines associated with immune and inflammatory responses were upregulated during PDCoV infection. Knockout of HSP90AB1 altered the upregulated levels of some cytokines. Taken together, our findings provide new insights into the host response to PDCoV infection from the transcriptome perspective, which will contribute to illustrating the molecular basis of the interaction between PDCoV and HSP90AB1.

(1) Background: Porcine deltacoronavirus (PDCoV) is a newly emerged enteric virus affecting pig breeding industries worldwide, and its pathogenic mechanism remains unclear. (2) Methods: In this study, we preliminarily identified the endocytic pathway of PDCoV in PK-15 cells, using six chemical inhibitors (targeting clathrin-mediated endocytosis, caveolae-mediated endocytosis, macropinocytosis pathway and endosomal acidification), overexpression of dominant-negative (DN) mutants to treat PK-15 cells and proteins knockdown. (3) Results: The results revealed that PDCoV entry was not affected after treatment with chlorpromazine (CPZ), 5-(N-ethyl-N-isopropyl) amiloride (EIPA)or ammonium chloride (NH4Cl), indicating that the entry of PDCoV into PK-15 cells were clathrin-, micropinocytosis-, PH-independent endocytosis. Conversely, PDCoV infection was sensitive to nystatin, dynasore and methyl-β-cyclodextrin (MβCD) with reduced PDCoV internalization, indicating that entry of PDCoV into PK-15 cells was caveolae-mediated endocytosis that required dynamin and cholesterol; indirect immunofluorescence and shRNA interference further validated these results. (4) Conclusions: In conclusion, PDCoV entry into PK-15 cells depends on caveolae-mediated endocytosis, which requires cholesterol and dynamin. Our finding is the first initial identification of the endocytic pathway of PDCoV in PK-15 cells, providing a theoretical basis for an in-depth understanding of the pathogenic mechanism of PDCoV and the design of new antiviral targets.

Porcine deltacoronavirus (PDCoV) is highly pathogenic to piglets, and no specific drugs or vaccines are available for the prevention and treatment of PDCoV infection, the need for antiviral therapies is pressing. HSP90 inhibitors have potent inhibitory effects against the replication of numerous viruses, hence we evaluated three HSP90 inhibitors, 17-AAG, VER-82576, and KW-2478, for their effects on PDCoV infection in vitro. We evaluated their effectivenesses at suppressing PDCoV by qRT-PCR, western blot, and TCID

Porcine deltacoronavirus (PDCoV) is an enteropathogen found in many pig producing countries. It can cause acute diarrhea, vomiting, dehydration, and death in newborn piglets, seriously affecting the development of pig breeding industries. To date, our knowledge of the pathogenesis of PDCoV and its interactions with host cell factors remains incomplete. Using Co-IP coupled with LC/MS-MS, we identified 67 proteins that potentially interact with PDCoV in LLC-PK1 cells; five of the identified proteins were chosen for further evaluation (IMMT, STAT1, XPO5, PIK3AP1, and TMPRSS11E). Five LLC-PK1 cell lines, each with one of the genes of interest knocked down, were constructed using CRISPR/cas9. In these knockdown cells lines, only STAT1

This study investigated the prevalence of antimicrobial resistant Enterococcus faecalis (E. faecalis) from ducks at slaughterhouses, analyzed antimicrobial resistance genes and virulence-associated genes of the isolates. Multilocus sequence typing (MLST) was performed to characterize their molecular characteristics. A total of 227 E. faecalis isolates (67.8%) were obtained from cecum (n = 114), cloaca (n = 50), skin (n = 59), and rinsed water (n = 4). These E. faecalis exhibited high level of resistance against tetracycline (95.6%), doxycycline (94.3%), linezolid (75.8%), erythromycin (72.2%), followed by norfloxacin (56.8%), vancomycin (38.3%), penicillin (36.1%), teicoplanin (30.8%). Lower level of resistance was found to high-level streptomycin (19.8%), imipenem (15.9%) and high-level gentamicin (5.7%). The vast majority of isolates (90.3%) were multidrug resistant (MDR). Moreover, the commonly observed resistance genes were optrA (90.7%) and ermB (90.3%), followed by aph(3’)-Ⅲ (86.8%), tetM (84.6%), acc(6’)-aph(2) (77.5%), blaZ (76.7%) and aac(6’)-Ie-aph(2”)-Ia (75.8%). The less frequently observed genes were vanC (19.8%), blaTEM (4.8%), vanM (2.6%), and vanA (0.4%). None of the strains carried aph(2”)-Ic and vanB genes. Furthermore, a high prevalence of ten virulence determinants was identified, and efaA (99.1%) was predominant, followed by eep (97.4%), srtA (96.9%), asa1 (95.6%), fsrB (92.1%), sprE (89.9%), aggA (63.9%), gelE (56.4%), esp (33.9%), and cylL (15.4%). Eleven isolates (4.9%) co-carried all of the tested virulence-associated genes. MLST analysis demonstrated that, E. faecalis isolates consisted of 12 known STs and 5 new STs, among which 6 of the identified STs were associated with nosocomial infection. Our data indicated that retail ducks serve as an important source of MDR E. faecalis with high pathogenicity potential, and suggested that transmission to humans could not be excluded.

Zika virus (ZIKV) is a mosquito-borne flavivirus that predominantly circulates between humans and Aedes mosquitoes. Clinical studies have shown that Zika viruria in patients persists for an extended period, and results in infectious virions being excreted. Here, we demonstrate that Aedes mosquitoes are permissive to ZIKV infection when breeding in urine or sewage containing low concentrations of ZIKV. Mosquito larvae and pupae, including from field Aedes aegypti can acquire ZIKV from contaminated aquatic systems, resulting in ZIKV infection of adult females. Adult mosquitoes can transmit infectious virions to susceptible type I/II interferon receptor-deficient (ifnagr-/-) C57BL/6 (AG6) mice. Furthermore, ZIKV viruria from infected AG6 mice can causes mosquito infection during the aquatic life stages. Our studies suggest that infectious urine could be a natural ZIKV source, which is potentially transmissible to mosquitoes when breeding in an aquatic environment., Here the authors show that Aedes mosquitoes can acquire ZIKV by breeding in contaminated aquatic systems, and that these infected mosquitoes can transmit ZIKV to susceptible mice. This suggests that human urine containing aquatic environments could contribute to ZIKV transmission.

Summary The arbovirus life cycle involves viral transfer between a vertebrate host and an arthropod vector, and acquisition of virus from an infected mammalian host by a vector is an essential step in this process. Here, we report that flavivirus nonstructural protein-1 (NS1), which is abundantly secreted into the serum of an infected host, plays a critical role in flavivirus acquisition by mosquitoes. The presence of dengue virus (DENV) and Japanese encephalitis virus (JEV) NS1s in the blood of infected interferon alpha and gamma receptor-deficient mice (AG6) facilitated virus acquisition by their native mosquito vectors because the protein enabled the virus to overcome the immune barrier of the mosquito midgut. Active immunization of AG6 mice with a modified DENV NS1 reduced DENV acquisition by mosquitoes and protected mice against a lethal DENV challenge, suggesting that immunization with NS1 could reduce the number of virus-carrying mosquitoes as well as the incidence of flaviviral diseases. Our study demonstrates that flaviviruses utilize NS1 proteins produced during their vertebrate phases to enhance their acquisition by vectors, which might be a result of flavivirus evolution to adapt to multiple host environments.