scholarly journals Porcine Reproductive and Respiratory Syndrome Virus Induces IL-1βProduction Depending on TLR4/MyD88 Pathway and NLRP3 Inflammasome in Primary Porcine Alveolar Macrophages

2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Jing Bi ◽  
Shuang Song ◽  
Liurong Fang ◽  
Dang Wang ◽  
Huiyuan Jing ◽  
...  

Porcine reproductive and respiratory syndrome virus (PRRSV) is anArterivirusthat has been devastating the swine industry worldwide since the late 1980s. Previous studies have reported that PRRSV infection induced the production of IL-1β. However, the cellular sensors and signaling pathways involved in this process have not been elucidated yet. Here, we studied the mechanisms responsible for the production of IL-1βin response to highly pathogenic PRRSV. Upon PRRSV infection of primary porcine alveolar macrophages, both mRNA expression and secretion of IL-1βwere significantly increased in a time- and dose-dependent manner. We also investigated the role of several pattern-recognition receptors and adaptor molecules in this response and showed that the TLR4/MyD88 pathway and its downstream signaling molecules, NF-κB, ERK1/2, and p38 MAPKs, were involved in IL-1βproduction during PRRSV infection. Treatment with specific inhibitors or siRNA knockdown assays demonstrated that components of the NLRP3 inflammasome were crucial for IL-1βsecretion but not for IL-1βmRNA expression. Furthermore, TLR4/MyD88/NF-κB signaling pathway was involved in PRRSV-induced expression of NLRP3 inflammasome components. Together, our results deciphered the pathways leading from recognition of PRRSV to the production and release of IL-1β, providing a deeper knowledge of the mechanisms of PRRSV-induced inflammation responses.

Viruses ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2267
Author(s):  
Xiaoping Wu ◽  
Junyang Fang ◽  
Qiuping Huang ◽  
Xu Chen ◽  
Zhongyi Guo ◽  
...  

Porcine reproductive and respiratory syndrome (PRRS), a significant viral infectious disease that commonly occurs among farmed pigs, leads to considerable economic losses to the swine industry worldwide. Major vault protein (MVP) is a host factor that induces type Ⅰ interferon (IFN) production. In this study, we evaluated the effect of MVP on PRRSV infection in CRL2843CD163 cell lines and porcine alveolar macrophages (PAMs). Our results showed that MVP expression was downregulated by PRRSV infection. Adenoviral overexpression of MVP inhibited PRRSV replication, whereas the siRNA knockdown of MVP promoted PRRSV replication. In addition, MVP knockdown has an adverse effect on the inhibitive role of MVP overexpression on PRRSV replication. Moreover, MVP could induce the expression of type Ⅰ IFNs and IFN-stimulated gene 15 (ISG15) in PRRSV-infected PAMs. Based on these results, MVP may be a potential molecular target of drugs for the effective prevention and treatment of PRRSV infection.


2019 ◽  
Author(s):  
huawei li ◽  
ruining wang ◽  
wenjia wang ◽  
yinfeng kang ◽  
mengmeng zhao

Abstract Background : Porcine reproductive and respiratory syndrome virus (PRRSV) is a serious pathogen that causes $664 million losses per year to the swine industry. There are few useful vaccines that can provide protection against PRRSV infection. 2′, 5′-oligoadenylate synthetase-like protein (OASL) has antiviral activity, this has not been shown for PRRSV and the mechanism is unknown. Methods : Expression of OASL in porcine alveolar macrophages induced by interferon (IFN)-b stimulation and PRRSV infection was examined by real-time polymerase chain reaction. Exogenous expression and knockdown of OASL were used to determine the role of OASL in the PRRSV replication cycle. The type I IFN signaling pathway was evaluated after OASL overexpression. Results : In this study, we found that the expression of OASL in porcine alveolar macrophages was significantly increased by IFN-b stimulation and PRRSV infection. Porcine-OASL-specific small interfering RNA (siRNA) promoted PRRSV replication, whereas exogenous expression of porcine OASL inhibited replication of the virus. The anti-PRRSV activity of porcine OASL was lost after knockdown of retinoic acid-inducible gene I ( DDX58 , also known as RIG-I ). Conclusions : Porcine OASL suppresses PRRSV replication.


2008 ◽  
Vol 89 (10) ◽  
pp. 2550-2564 ◽  
Author(s):  
Sem Genini ◽  
Peter L. Delputte ◽  
Roberto Malinverni ◽  
Maria Cecere ◽  
Alessandra Stella ◽  
...  

Porcine reproductive and respiratory syndrome is a major cause of economic loss for the swine industry worldwide. Porcine reproductive and respiratory syndrome virus (PRRSV) triggers weak and atypical innate immune responses, but key genes and mechanisms by which the virus interferes with the host innate immunity have not yet been elucidated. In this study, genes that control the response of the main target of PRRSV, porcine alveolar macrophages (PAMs), were profiled in vitro with a time-course experiment spanning the first round of virus replication. PAMs were obtained from six piglets and challenged with the Lelystad PRRSV strain, and gene expression was investigated using Affymetrix microarrays and real-time PCR. Of the 1409 differentially expressed transcripts identified by analysis of variance, two, five, 25, 16 and 100 differed from controls by a minimum of 1.5-fold at 1, 3, 6, 9 and 12 h post-infection (p.i.), respectively. A PRRSV infection effect was detectable between 3 and 6 h p.i., and was characterized by a consistent downregulation of gene expression, followed by the start of the host innate immune response at 9 h p.i. The expression of beta interferon 1 (IFN-β), but not of IFN-α, was strongly upregulated, whilst few genes commonly expressed in response to viral infections and/or induced by interferons were found to be differentially expressed. A predominance of anti-apoptotic transcripts (e.g. interleukin-10), a shift towards a T-helper cell type 2 response and a weak upregulation of tumour necrosis factor-α expression were observed within 12 h p.i., reinforcing the hypotheses that PRRSV has developed sophisticated mechanisms to escape the host defence.


2019 ◽  
Vol 50 (1) ◽  
Author(s):  
Ye Zhou ◽  
Saixiang Feng ◽  
Xinyi He ◽  
Qun Zhou ◽  
Yuanwei Wang ◽  
...  

AbstractOuter membrane protein P2 (OmpP2) of the virulent Haemophilus (Glaesserella) parasuis has been shown to induce the release of proinflammatory cytokines. The OmpP2 protein is composed of eight or nine surface-exposed loops, but it is unclear which of them participates in the OmpP2-induced inflammatory response. In this study, we synthesized linear peptides corresponding to surface-exposed loops L1–L8 of OmpP2 from the virulent H. parasuis SC096 strain to stimulate porcine alveolar macrophages (PAMs) in vitro. We found that both L7 and L8 significantly upregulated the mRNA expression of interleukin (IL)-1α, IL-1β, IL-6, IL-8, IL-17, and IL-23 and the chemokines CCL-4 and CCL-5 in a time- and dose-dependent manner. Additionally, we constructed ompP2ΔLoop7 and ompP2ΔLoop8 mutant SC096 strains and extracted their native OmpP2 proteins to stimulate PAMs. These mutant proteins induced significantly less mRNA expression of inflammatory cytokines than SC096 OmpP2. Next, the amino acid sequences of L7 and L8 from 15 serovars of H. parasuis OmpP2 were aligned. These sequences were relatively conserved among the most virulent reference strains, suggesting that L7 and L8 are the most active peptides of the OmpP2 protein. Furthermore, L7 and L8 significantly upregulated the NF-κB and AP-1 activity levels based on luciferase reporter assays in a dose-dependent manner. Therefore, our results demonstrated that both surface-exposed loops L7 and L8 of H. parasuis OmpP2 induced the expression of proinflammatory cytokines possibly by activating the NF-κB and MAPK signalling pathways in cells infected by H. parasuis.


Viruses ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 655
Author(s):  
Yujiao Zhang ◽  
Fei Gao ◽  
Liwei Li ◽  
Kuan Zhao ◽  
Shan Jiang ◽  
...  

Porcine reproductive and respiratory syndrome virus (PRRSV) is one of the most important pathogens in the swine industry worldwide. Our previous study had indicated that proprotein convertase subtilisin/kexin type 9 (PCSK9) was a responsive gene in porcine alveolar macrophages (PAMs) upon PRRSV infection. However, whether PCSK9 impacts the PRRSV replication and how the PRRSV modulates host PCSK9 remains elusive. Here, we demonstrated that PCSK9 protein suppressed the replication of both type-1 and type-2 PRRSV species. More specifically, the C-terminal domain of PCSK9 was responsible for the antiviral activity. Besides, we showed that PCSK9 inhibited PRRSV replication by targeting the virus receptor CD163 for degradation through the lysosome. In turn, PRRSV could down-regulate the expression of PCSK9 in both PAMs and MARC-145 cells. By screening the nonstructural proteins (nsps) of PRRSV, we showed that nsp11 could antagonize PCSK9’s antiviral activity. Furthermore, mutagenic analyses of PRRSV nsp11 revealed that the endoribonuclease activity of nsp11 was critical for antagonizing the antiviral effect of PCSK9. Collectively, our data provide further insights into the interaction between PRRSV and the cell host and offer a new potential target for the antiviral therapy of PRRSV.


Molecules ◽  
2019 ◽  
Vol 24 (5) ◽  
pp. 887
Author(s):  
Amina Khatun ◽  
Sun Park ◽  
Nadeem Shabir ◽  
Salik Nazki ◽  
A-Rum Kang ◽  
...  

DiNap [(E)-1-(2-hydroxy-4,6-dimethoxyphenyl)-3-(naphthalen-1-yl)prop-2-en-1-one], an analog of a natural product (the chalcone flavokawain), was synthesized and characterized in this study. Porcine reproductive and respiratory syndrome virus (PRRSV) is the most challenging threat to the swine industry worldwide. Currently, commercially available vaccines are ineffective for controlling porcine reproductive and respiratory syndrome (PRRS) in pigs. Therefore, a pharmacological intervention may represent an alternative control measure for PRRSV infection. Hence, the present study evaluated the effects of DiNap on the replication of VR2332 (a prototype strain of type 2 PRRSV). Initially, in vitro antiviral assays against VR2332 were performed in MARC-145 cells and porcine alveolar macrophages (PAMs). Following this, a pilot study was conducted in a pig model to demonstrate the effects of DiNap following VR2332 infection. DiNap inhibited VR2332 replication in both cell lines in a dose-dependent manner, and viral growth was completely suppressed at concentrations ≥0.06 mM, without significant cytotoxicity. Consistent with these findings, in the pig study, DiNap also reduced viral loads in the serum and lungs and enhanced the weight gain of pigs following VR2332 infection, as indicated by comparison of the DiNap-treated groups to the untreated control (NC) group. In addition, DiNap-treated pigs had fewer gross and microscopic lesions in their lungs than NC pigs. Notably, virus transmission was also delayed by approximately 1 week in uninfected contact pigs within the same group after treatment with DiNap. Taken together, these results suggest that DiNap has potential anti-PRRSV activity and could be useful as a prophylactic or post-exposure treatment drug to control PRRSV infection in pigs.


2018 ◽  
Vol 93 (4) ◽  
Author(s):  
Lizhen Wang ◽  
Lu Zhang ◽  
Baichen Huang ◽  
Kuokuo Li ◽  
Gaopeng Hou ◽  
...  

ABSTRACTPorcine reproductive and respiratory syndrome (PRRS) is of great concern to the swine industry due to pandemic outbreaks of the disease, current ineffective vaccinations, and a lack of efficient antiviral strategies. In our previous study, a PRRSV Nsp9-specific nanobody, Nb6, was successfully isolated, and the intracellularly expressed Nb6 could dramatically inhibit PRRSV replication in MARC-145 cells. However, despite its small size, the application of Nb6 protein in infected cells is greatly limited, as the protein itself cannot enter the cells physically. In this study, atrans-activating transduction (TAT) peptide was fused with Nb6 to promote protein entry into cells. TAT-Nb6 was expressed as an inclusion body inEscherichia coli, and indirect enzyme-linked immunosorbent assays and pulldown assays showed thatE. coli-expressed TAT-Nb6 maintained the binding ability toE. coli-expressed or PRRSV-encoded Nsp9. We demonstrated that TAT delivered Nb6 into MARC-145 cells and porcine alveolar macrophages (PAMs) in a dose- and time-dependent manner, and TAT-Nb6 efficiently inhibited the replication of several PRRSV genotype 2 strains as well as a genotype 1 strain. Using a yeast two-hybrid assay, Nb6 recognition sites were identified in the C-terminal part of Nsp9 and spanned two discontinuous regions (Nsp9aa454–551and Nsp9aa599–646). Taken together, these results suggest that TAT-Nb6 can be developed as an antiviral drug for the inhibition of PRRSV replication and controlling PRRS disease.IMPORTANCEThe pandemic outbreak of PRRS, which is caused by PRRSV, has greatly affected the swine industry. We still lack an efficient vaccine, and it is an immense challenge to control its infection. An intracellularly expressed Nsp9-specific nanobody, Nb6, has been shown to be able to inhibit PRRSV replication in MARC-145 cells. However, its application is limited, because Nb6 cannot physically enter cells. Here, we demonstrated that the cell-penetrating peptide TAT could deliver Nb6 into cultured cells. In addition, TAT-Nb6 fusion protein could suppress the replication of various PRRSV strains in MARC-145 cells and PAMs. These findings may provide a new approach for drug development to control PRRS.


2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Lu Zhang ◽  
Lizhen Wang ◽  
Shuaishuai Cao ◽  
Huanhuan Lv ◽  
Jingjing Huang ◽  
...  

AbstractPorcine reproductive and respiratory syndrome virus (PRRSV) is a highly contagious virus that has led to enormous economic loss worldwide because of ineffective prevention and treatment. In view of their minimized size, high target specificity and affinity, nanobodies have been extensively investigated as diagnostic tools and treatments of many diseases. Previously, a PRRSV Nsp9-specific nanobody (Nb6) was identified as a PRRSV replication inhibitor. When it was fused with cell-penetrating peptide (CPP) TAT, Nb6-TAT could enter the cells for PRRSV suppression. However, delivery of molecules by CPP lack cell specificity and have a short duration of action. PRRSV has a tropism for monocyte/macrophage lineage, which expresses high levels of Fcγ receptors. Herein, we designed a nanobody containing porcine IgG Fc (Fcγ) to inhibit PRRSV replication in PRRSV permissive cells. Fcγ fused Nb6 chimeric antibody (Nb6-pFc) was assembled into a dimer with interchain disulfide bonds and expressed in a Pichia pastoris system. The results show that Nb6-pFc exhibits a well-binding ability to recombinant Nsp9 or PRRSV-encoded Nsp9 and that FcγR-mediated endocytosis of Nb6-pFc into porcine alveolar macrophages (PAM) was in a dose-dependent manner. Nb6-pFc can inhibit PRRSV infection efficiently not only by binding with Nsp9 but also by upregulating proinflammatory cytokine production in PAM. Together, this study proposes the design of a porcine IgG Fc-fused nanobody that can enter PRRSV susceptible PAM via FcγR-mediated endocytosis and inhibit PRRSV replication. This research reveals that nanobody-Fcγ chimeric antibodies might be effective for the control and prevention of monocyte/macrophage lineage susceptible pathogeneses.


2020 ◽  
Vol 4 (Supplement_2) ◽  
pp. 1231-1231
Author(s):  
Giulio Pasinetti

Abstract Objectives Chronic stress activates danger-associated molecular patterns (DAMPs), stimulating the NLRP3 inflammasome. NLRP3 activation triggers the release of pro-inflammatory cytokine IL-1β. The activity of the NLRP3 inflammasome propagates pro-inflammatory signaling cascades implicated in the onset of depression. Our previous studies show that polyphenolic compounds were found to ameliorate stress induced depression in mouse models. However, the relevant mechanism has not been identified. This study examined the effect of administering polyphenols on DAMP signaling in enriched mice microglia. Methods This study examined the effect of administering polyphenols on DAMP signaling in mice microglia. To recapitulate stress-induced depression, mice underwent chronic unpredictable stress (CUS). Microglia were isolated at various time points throughout the CUS protocol. We also assessed long-term persistent changes after CUS and susceptibility to subthreshold unpredictable stress (US) re-exposure. Results Interestingly, the development of US – induced depression and anxiety depended upon a previous exposure to CUS. We found that CUS caused robust upregulation of IL-1β mRNA in enriched microglia, an effect that persists for up to 4 weeks following CUS exposure. Following the subthreshold US re-exposure, we observed the upregulation of pro- IL-1β as well as pro-receptor for advanced glycation end products (RAGE). Toll-like receptor 4 (TLR-4) was not. We also observed an increase in RAGE mRNA expression when mice were exposed to US prior to the start of the CUS paradigm. Importantly, a primary exposure to US, was sufficient to increase RAGE mRNA expression. We found that polyphenol administration significantly improved CUS-induced depressive-like phenotypes and also reversed neuroinflammation in mice. Treatment with dietary flavonoids prevented upregulation of IL-1β, RAGE mRNA, which reflects the ability of polyphenols that may have begun following the primary exposure to US. Conclusions Taken all together, the results provide evidence of the role of dietary polyphenols in preventing persistent microglial activation, which has been shown to result in reduced long term vulnerability to depressive-like behaviors following expose to chronic stress. Funding Sources This study was supported by a P50 CARBON Center grant from the NCCIH/ODS.


2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Hongfang Ma ◽  
Rui Li ◽  
Longguang Jiang ◽  
Songlin Qiao ◽  
Xin-xin Chen ◽  
...  

AbstractPorcine reproductive and respiratory syndrome (PRRS) is a serious disease burdening global swine industry. Infection by its etiological agent, PRRS virus (PRRSV), shows a highly restricted tropism of host cells and has been demonstrated to be mediated by an essential scavenger receptor (SR) CD163. CD163 fifth SR cysteine-rich domain (SRCR5) is further proven to play a crucial role during viral infection. Despite intense research, the involvement of CD163 SRCR5 in PRRSV infection remains to be elucidated. In the current study, we prepared recombinant monkey CD163 (moCD163) SRCR5 and human CD163-like homolog (hCD163L1) SRCR8, and determined their crystal structures. After comparison with the previously reported crystal structure of porcine CD163 (pCD163) SRCR5, these structures showed almost identical structural folds but significantly different surface electrostatic potentials. Based on these differences, we carried out mutational research to identify that the charged residue at position 534 in association with the one at position 561 were important for PRRSV-2 infection in vitro. Altogether the current work sheds some light on CD163-mediated PRRSV-2 infection and deepens our understanding of the viral pathogenesis, which will provide clues for prevention and control of PRRS.


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