Classical Swine Fever Virus Infection and Its NS4A Protein Expression Induce IL-8 Production through MAVS Signaling Pathway in Swine Umbilical Vein Endothelial Cells
Abstract:Classical swine fever virus (CSFV) infection causes a severe disease of pigs, which is characterized by hemorrhage, disseminated intravascular coagulation, and leucopenia. IL-8, a main chemokine and activator of neutrophils, regulates the permeability of endothelium, which may be related to the hemorrhage upon CSFV infection. Until now, the molecular mechanisms of IL-8 regulation during CSFV infection are poorly defined. Here, we showed that CSFV infection induced IL-8 production and the upregulation of IL-8 r… Show more
“…The average crystallite size was found to be 16.8 nm which was in close agreement with DLS analysis. No secondary peaks were observed, hence the crystalline stable AgNP formation from the endophytic extract is justified with the previous XRD data green synthesized from endophytic bacteria, fungi and plant extracts [ 36 , 51 , 52 ]. Fig.…”
Endophyte mediated nanoparticles fabrication were emerging as a new frontier in nanomedicines that produce high biocompatible and functionalized silver nanoparticles. In this study, silver nanoparticles were successfully biosynthesized from the extracellular extract of endophytic bacterium
Pantoea anthophila
isolated from the stem of
Waltheria indica
for the first time. The synthesized nanoparticles showed a strong absorption band at 410 nm in the UV–Visible range. The dynamic light scattering and zeta potential analysis indicated that the average particle size was 16 nm at 5.30 mV. FTIR spectrum displayed the presence of various functional groups at 3423.65, 1633.71, 1022.27, 607.58 cm
−1
that stabilised the nanoparticle. X-ray diffraction peaks were conferred to 100, 200, 220 and 311 planes of a face centred cubic structure. TEM and SEM micrograph revealed the spherical-shaped, polycrystalline nature with the presence of elemental silver analysed by EDAX. Selected area electron diffraction also confirms the orientation of silver nanoparticles with X-ray diffraction analysis. Antimicrobial activity against 10 different human pathogenic bacteria and fungi showed a broad spectrum inhibition against both Gram-positive and Gram-negative bacteria. Among the bacterial pathogens,
B. Subtilis
exhibited low activity compared to other pathogens.
C. albicans
was greatly controlled than other fungal species. A strong free radical scavenging activity of silver nanoparticles with IC
50
values 31.29 ± 0.73, 19.83 ± 1.57, 35.64 ± 0.94, 42.07 ± 1.30, 29.70 ± 2.26, 29.10 ± 0.82, 36.80 ± 0.63 μg/ml was obtained in different antioxidant assays that were comparable to the reference. The study suggests that the silver nanoparticles can be biosynthesized from endophytic
P. anthophila
metabolites with significant therapeutic potential. With proper validation, the biosynthesized silver nanoparticles can be developed as a promising antiviral and anticancer drug candidate.
“…The average crystallite size was found to be 16.8 nm which was in close agreement with DLS analysis. No secondary peaks were observed, hence the crystalline stable AgNP formation from the endophytic extract is justified with the previous XRD data green synthesized from endophytic bacteria, fungi and plant extracts [ 36 , 51 , 52 ]. Fig.…”
Endophyte mediated nanoparticles fabrication were emerging as a new frontier in nanomedicines that produce high biocompatible and functionalized silver nanoparticles. In this study, silver nanoparticles were successfully biosynthesized from the extracellular extract of endophytic bacterium
Pantoea anthophila
isolated from the stem of
Waltheria indica
for the first time. The synthesized nanoparticles showed a strong absorption band at 410 nm in the UV–Visible range. The dynamic light scattering and zeta potential analysis indicated that the average particle size was 16 nm at 5.30 mV. FTIR spectrum displayed the presence of various functional groups at 3423.65, 1633.71, 1022.27, 607.58 cm
−1
that stabilised the nanoparticle. X-ray diffraction peaks were conferred to 100, 200, 220 and 311 planes of a face centred cubic structure. TEM and SEM micrograph revealed the spherical-shaped, polycrystalline nature with the presence of elemental silver analysed by EDAX. Selected area electron diffraction also confirms the orientation of silver nanoparticles with X-ray diffraction analysis. Antimicrobial activity against 10 different human pathogenic bacteria and fungi showed a broad spectrum inhibition against both Gram-positive and Gram-negative bacteria. Among the bacterial pathogens,
B. Subtilis
exhibited low activity compared to other pathogens.
C. albicans
was greatly controlled than other fungal species. A strong free radical scavenging activity of silver nanoparticles with IC
50
values 31.29 ± 0.73, 19.83 ± 1.57, 35.64 ± 0.94, 42.07 ± 1.30, 29.70 ± 2.26, 29.10 ± 0.82, 36.80 ± 0.63 μg/ml was obtained in different antioxidant assays that were comparable to the reference. The study suggests that the silver nanoparticles can be biosynthesized from endophytic
P. anthophila
metabolites with significant therapeutic potential. With proper validation, the biosynthesized silver nanoparticles can be developed as a promising antiviral and anticancer drug candidate.
“…It is reported that PCV2 can induce IFN-β production via the RIG-1/ MDA-5/MAVS/IRF signaling pathway in PK-15 cell [15]. Classical swine fever virus can induce the production of IL-8 and other proinflammatory cytokines via the RIG-I/MDA-5 pathway [16,17]. But whether the mechanism of endothelial-derived IL-8 production is consistent to that of other cell-derived IL-8 is still unknown.…”
Background: Dysfunction of endothelial cells and vascular system is one of the most important pathological changes of porcine circovirus disease (PCVD) caused by porcine circovirus type 2 (PCV2). PCV2-infected endothelial cells can upregulate the production of endothelial-derived IL-8, which can inhibit the maturation of dendritic cells. Endothelial-derived IL-8 has different structural and biological characteristics compared with monocyte-derived IL-8. However, the mechanism of endothelial-derived IL-8 production is still unclear. Results: Key molecules of RIG-I-like signaling pathway RIG-I, MDA-5, MAVS and a key molecule of JNK signaling pathway c-Jun in PCV2-infected porcine iliac artery endothelial cells (PIECs) were upregulated significantly detected with quantitative PCR, Western blot and fluorescence confocal microscopy, while no significant changes were found in NF-κB signaling pathway. Meanwhile, the expression of endothelial-derived IL-8 was downregulated after RIG-I, MDA-5, or MAVS genes in PIECs were knocked down and PIECs were treated by JNK inhibitor. Conclusions: PCV2 can activate RIG-I/MDA-5/MAVS/JNK signaling pathway to induce the production of endothelialderived IL-8 in PIECs, which provides an insight into the further study of endothelial dysfunction and vascular system disorder caused by PCV2.
“…The virus replication process includes adsorption, internalization, uncoating, biosynthesis, assembly and release. A previous study has demonstrated that NS4A promotes CSFV replication [ 12 ]. However, the molecular mechanism has remained unclear.…”
Section: Discussionmentioning
confidence: 99%
“…The CSFV genome is approximately 12.3 kb in length and encodes a polyprotein precursor that is further proteolytically processed into four structural proteins (C, E rns , E1 and E2) and eight nonstructural proteins (N pro , p7, NS2, NS3, NS4A, NS4B, NS5A and NS5B) [ 10 , 11 ]. CSFV NS4A is an 8 kDa protein that is located in the nucleus and cytoplasm [ 12 ]. NS4A is a cofactor of the NS3 protease that assists the cleavage of downstream nonstructural proteins and is involved in the formation of infectious virions.…”
Section: Introductionmentioning
confidence: 99%
“…NS4A is a cofactor of the NS3 protease that assists the cleavage of downstream nonstructural proteins and is involved in the formation of infectious virions. CSFV NS4A induces IL-8 production by enhancing the mitochondrial antiviral signalling protein (MAVS) pathway and promoting CSFV replication [ 12 ]. However, the function of NS4A during CSFV infection needs to be further elucidated.…”
Background
Classical swine fever (CSF) is a severe disease of pigs that results in huge economic losses worldwide and is caused by classical swine fever virus (CSFV). CSFV nonstructural protein 4 A (NS4A) plays a crucial role in infectious CSFV particle formation. However, the function of NS4A during CSFV infection is not well understood.
Results
In this study, we used RNA-seq to investigate the functional role of CSFV NS4A in PK-15 cells. A total of 3893 differentially expressed genes (DEGs) were identified in PK-15 cells expressing NS4A compared to cells expressing the empty vector (NC). Twelve DEGs were selected and further verified by RT‒qPCR. GO and KEGG enrichment analyses revealed that these DEGs were associated with multiple biological functions, including cell adhesion, apoptosis, host defence response, the inflammatory response, the immune response, and autophagy. Interestingly, some genes associated with host immune defence and inflammatory response were downregulated, and some genes associated with host apoptosis and autophagy were upregulated.
Conclusion
CSFV NS4A inhibits the innate immune response, and suppresses the expression of important genes associated with defence response to viruses and inflammatory response, and regulates cell adhesion, apoptosis and autophagy.
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