Activation of the TLR/MyD88/NF-κB signal pathway contributes to changes in IL-4 and IL-12 production in piglet lymphocytes infected with porcine circovirus type 2 in vitro

Genotypic diversity and immunological implications of porcine circovirus: Inspiration from PCV1 to PCV4

Porcine circovirus (PCV) is a group of DNA viruses that cause diseases in pigs, with multiple genotypes ranging from PCV1 to PCV4. PCV1 is generally considered non-pathogenic, while PCV2 can cause severe immune system damage, especially associated with porcine multisystemic wasting syndrome (PMWS). PCV2 has a genetic homology of about 68 % but differs from PCV1 in antigenicity and phenotype. PCV3 and PCV4 have lower genetic homology with PCV1 and PCV2, with limited research available on their pathogenicity. During virus infection, the host's innate immune system detects PCVs through pattern recognition receptors (PRRs) like TLRs and NLRs. PCV disrupts immune pathways, including interferon and NF-κB pathways, aiding viral replication and causing immunosuppression. This review systematically compares the characteristics and pathogenicity of different genotypes of PCV and their interactions with the host's immune system, aiming to better understand the mechanisms of PCV infection and provide a theoretical basis for prevention and treatment.

cAMP-PKA signaling pathway and anxiety: Where do we go next?

Cyclic adenosine monophosphate (cAMP) is an intracellular second messenger that is derived from the conversion of adenosine triphosphate catalysed by adenylyl cyclase (AC). Protein kinase A (PKA), the main effector of cAMP, is a dimeric protein kinase consisting of two catalytic subunits and two regulatory subunits. When cAMP binds to the regulatory subunits of PKA, it leads to the dissociation and activation of PKA, which allows the catalytic subunit of PKA to phosphorylate target proteins, thereby regulating various physiological functions and metabolic processes in cellular function. Recent researches also implicate the involvement of cAMP-PKA signaling in the pathologenesis of anxiety disorder. However, there are still debates on the prevention and treatment of anxiety disorders from this signaling pathway. To review the function of cAMP-PKA signaling in anxiety disorder, we searched the publications with the keywords including "cAMP", "PKA" and "Anxiety" from Pubmed, Embase, Web of Science and CNKI databases. The results showed that the number of publications on cAMP-PKA pathway in anxiety disorder tended to increase. Bioinformatics results displayed a close association between the cAMP-PKA pathway and the occurrence of anxiety. Mechanistically, cAMP-PKA signaling could influence brain-derived neurotrophic factor and neuropeptide Y and participate in the regulation of anxiety. cAMP-PKA signaling could also oppose the dysfunctions of gamma-aminobutyric acid (GABA), intestinal flora, hypothalamic-pituitary-adrenal axis, neuroinflammation, and signaling proteins (MAPK and AMPK) in anxiety. In addition, chemical agents with the ability to activate cAMP-PKA signaling demonstrated therapy potential against anxiety disorders. This review emphasizes the central roles of cAMP-PKA signaling in anxiety and the targets of the cAMP-PKA pathway would be potential candidates for treatment of anxiety. Nevertheless, more laboratory investigations to improve the therapeutic effect and reduce the adverse effect, and continuous clinical research will warrant the drug development.

Porcine circovirus type 2 ORF5 induces an inflammatory response by up-regulating miR-21 levels through targeting nuclear ssc-miR-30d

Porcine circovirus type 2 (PCV2) infection leads to multi-system inflammation in pigs, and this effect can be achieved by upregulating host miR-21. The underlying mechanism of miR-21 regulates PCV2-induced inflammation is already known, however, how PCV2 regulates miR-21 levels and function using both autonomic and host factors remains to be further revealed. Here we present the first evidence that PCV2 ORF5 induces an inflammatory response by up-regulating miR-21 level through targeting nuclear miR-30d. In this study, we found that overexpression of ORF5 significantly increased miR-21 level and promoted the expression of inflammatory cytokines and activation of the NF-κB pathway, while ORF5 mutation had the opposite effect. Moreover, the differential expression of miR-21 could significantly change the pro-inflammatory effect of ORF5, indicating that ORF5 promotes inflammatory response by up-regulating miR-21. Bioinformatics analysis and clinical detection found that nuclear miR-30d was significantly down-regulated after ORF5 overexpression and PCV2 infection, and targeted pri-miR-21 and PCV2 ORF5. Functionally, we found that miR-30d inhibited the levels of miR-21 and inflammatory cytokines in cells. Mechanistically, we demonstrated that ORF5 inhibits miR-30d expression levels through direct binding but not via the circRNA pathway, and miR-30d inhibits miR-21 levels by targeting pri-miR-21. In summary, the present study revealed the molecular mechanism of ORF5 upregulation of miR-21, further refined the molecular chain of PCV2-induced inflammatory response and elucidated the role of miRNAs in it.

Network pharmacology-based analysis on geniposide, a component of gardenia jasminoides, beneficial effects to alleviate LPS-induced immune stress in piglets

Geniposide is the main medicinal component of Gardenia jasminoides, and its content is approximately 3-8% depending on its origin. Geniposide is a class of cyclic enol ether terpene glucoside compounds with strong antioxidant, free radical quenching and cancer-inhibiting activities. Many studies have reported that geniposide has hepatoprotective, cholestatic, neuroprotective, blood sugar and blood lipid regulation, soft tissue damage treatment, antithrombotic, antitumor and other effects. As a traditional Chinese medicine, gardenia, whether used as gardenia alone, as the monomer geniposide or as the effective part of cyclic either terpenoids, has been reported to have anti-inflammatory effects when used in the right amounts. Recent studies have found that geniposide has important roles in pharmacological activities such as anti-inflammation activity, inhibition of the NF-κB/IκB pathway, and cell adhesion molecule production. In this study, we predicted the anti-inflammatory and antioxidant effects of geniposide in piglets through network pharmacology based on the LPS-induced inflammatory response-regulated signaling pathway. The effects of geniposide on changes in inflammatory pathways and cytokine levels in the lymphocytes of inflammation-stressed piglets were investigated using in vivo and in vitro models of piglet lipopolysaccharide-induced oxidative stress. Network pharmacology identified 23 target genes, of which the main pathways of action were lipid and atherosclerosis, fluid shear stress and atherosclerosis, and Yersinia infection. The main relevant target genes were VEGFA, ROCK2, NOS3, and CCL2. Validation experiments showed that the interventional effects of geniposide reduced the relative expression of NF-κB pathway proteins and genes, restored the expression of COX-2 genes to normal levels, and increased the relative expression of tight junction proteins and genes in IPEC-J2 cells. This indicates that the addition of geniposide can alleviate inflammation and improve the level of cellular tight junctions.

PDZK1 upregulates nitric oxide production through the PI3K/ERK2 pathway to inhibit porcine circovirus type 2 replication

Porcine circovirus type 2 (PCV2) is the causative agent of porcine circovirus-associated disease. Changes in host cell gene expression are induced by PCV2 infection. Here, we showed that porcine PDZ Domain-Containing 1 (PDZK1) expression was enhanced during PCV2 infection and that overexpression of PDZK1 inhibited the expression of PCV2 Cap protein. PCV2 genomic DNA copy number and viral titers were decreased in PDZK1-overexpressing PK-15B6 cells. PDZK1 knockdown enhanced the replication of PCV2. Overexpression of PDZK1 activated the phosphoinositide 3-kinase (PI3K)/ERK2 signaling pathway to enhance nitric oxide (NO) levels, while PDZK1 knockdown had the opposite effects. A PI3K inhibitor (LY294002) and a NO synthase inhibitor (L-NAME hydrochloride) decreased the activity of PDZK1 in restricting PCV2 replication. ERK2 knockdown enhanced the proliferation of PCV2 by decreasing levels of NO. Levels of interleukin (IL)- 4 mRNA were reduced in PDZK1 knockdown and ERK2 knockdown PK-15B6 cells. Increased IL-4 mRNA levels were unable to decrease NO production in PDZK1-overexpressing cells. Thus, we conclude that PDZK1 affected PCV2 replication by regulating NO production via PI3K/ERK2 signaling. PDZK1 affected IL-4 expression through the PI3K/ERK2 pathway, but PDZK1 modulation of PCV2 replication occurred independently of IL-4. Our results contribute to understanding the biological functions of PDZK1 and provide a theoretical basis for the pathogenic mechanisms of PCV2.

The Effects of Fenugreek Extract on Growth Performance, Serum Biochemical Indexes, Immunity and NF-κB Signaling Pathway in Broiler

In order to study the regulation of Fenugreek seed extract (FSE) on the immunity of broilers, and explore the appropriate amount of FSE in broilers' production, 1-day-old yellow feather broilers with a total of 420 birds were randomly allocated into seven treatments. Each treatment had six replicates, with 10 birds per replicate. The two control groups were the basic fodder group fed with basal diet and the bacitracin zinc group added 30 mg/kg bacitracin zinc to the basal diet. Experimental groups included five levels of FSE (50, 100, 200, 400, and 800 mg/kg FSE to the basal diet, respectively). The pre-test period was 7 days and the formal test lasted for 56 days. The results showed that the average daily gain (ADG) of 50 and 800 mg/kg FSE groups was significantly increased (P < 0.01), and the feed to gain ratio (F/G) of FSE groups was significantly decreased (P < 0.01) compared with the basic fodder and the bacitracin zinc groups. Compared with the basic fodder group, the serum total cholesterol (TC) content in the FSE groups was significantly decreased (P < 0.05), the serum low density lipoprotein cholesterol (LDL-C) content of 50, 100, and 800 mg/kg FSE groups was significantly lower than that of the basic fodder group (P < 0.05). Compared with the basic fodder and bacitracin zinc groups, the serum immunoglobulins (IgG, IgM, IgA) content of 100 and 200 mg/kg FSE groups were significantly increased (P < 0.05). Compared with the bacitracin zinc group, the serum interleukins (IL-1, IL-10) content of 400 mg/kg FSE group were significantly increased (P ≤ 0.05), and the serum interferon-γ (IFN-γ) content of 100 and 200 mg/kg FSE groups was significantly increased (P < 0.05). Compared with the basic fodder group, the lower doses (0–400 mg/kg) of FSE had no significant effect on the mRNA expression of toll-like receptors 4/ myeloid differentiation factor 88/ nuclear factor-κB (TLR4/MyD88/NF-κB) signaling pathways (P > 0.05). The 800 mg/kg FSE treatment group significantly increased the expression levels of nuclear factor-κB (NF-κB) mRNA in the spleen of broilers (P < 0.05). The zinc bacitracin group significantly increased the expression levels of myeloid differentiation factor 88 (MyD88) and nuclear factor-κB (NF-κB) mRNA (P ≤ 0.05). The results showed that FSE could promote the secretion of immunoglobulins, regulate the body's cytokines, and have a positive effect on immunity in broilers. Furthermore, the recommended supplement of FSE is 100 mg/kg in the broiler diet.

Microencapsulated probiotic Lactiplantibacillus plantarum and/or Pediococcus acidilactici strains ameliorate diarrhoea in piglets challenged with enterotoxigenic Escherichia coli

Lactiplantibacillus plantarum (strains 22F and 25F) and Pediococcus acidilactici (strain 72N) have displayed antibacterial activity in vitro, suggesting that they could be used to support intestinal health in pigs. The aim of this study was to determine if microencapsulated probiotics could reduce the severity of infection with enterotoxigenic Escherichia coli (ETEC) in weaned pigs. Sixty healthy neonatal piglets were cross-fostered and separated into five groups. Piglets to be given the microencapsulated probiotics received these orally on days 0, 3, 6, 9, and 12. Only piglets in groups 1 and 5 did not receive probiotics: those in groups 2 and 4 received the three microencapsulated probiotic strains (multi-strain probiotic), and piglets in group 3 received microencapsulated P. acidilactici strain 72N. After weaning, the pigs in groups 3-5 were challenged with 5 mL (at 10⁹ CFU/mL) of pathogenic ETEC strain L3.2 carrying the k88, staP, and stb virulence genes. The multi-strain probiotic enhanced the average daily gain (ADG) and feed conversion ratio (FCR) of weaned piglets after the ETEC challenge (group 4), whilst supplementing with the single-strain probiotic increased FCR (group 3). Piglets in groups 3 and 4 developed mild to moderate diarrhoea and fever. In the probiotic-fed piglets there was an increase in lactic acid bacteria count and a decrease in E. coli count in the faeces. By using real-time PCR, virulence genes were detected at lower levels in the faeces of pigs that had received the probiotic strains. Using the MILLIPLEX MAP assay, probiotic supplementation was shown to reduce pro-inflammatory cytokines (IL-1α, IL-6, IL-8, and TNFα), while group 4 had high levels of anti-inflammatory cytokine (IL-10). Challenged piglets receiving probiotics had milder intestinal lesions with better morphology, including greater villous heights and villous height per crypt depth ratios, than pigs just receiving ETEC. In conclusion, prophylactic administration of microencapsulated probiotic strains may improve outcomes in weaned pigs with colibacillosis.

Zbtb10 transcription factor is crucial for murine cDC1 activation and cytokine secretion

Dendritic cell (DC) activation and cytokine production is tightly regulated. In this study, we found that Zbtb10 expression is activation dependent and it is essential for the immunogenic function of cDC1. Zbtb10 knockdown (KD) significantly reduced the expression of co-stimulatory genes CD80 and CD86 along with cytokines including IL-12, IL-6, and IL-10, in activated cDC1 Mutu-DC line. Consequently, the clonal expansion of CD44⁺ effector T cells in co-cultured CD4⁺ T cells was drastically reduced owing to significantly reduced IL-2. At the same time, these CD44⁺ effector T cells were unable to differentiate toward Tbet⁺ IFNγ⁺ Th1 subtype. Instead, an increased frequency of Th2 cells expressing GATA3⁺ and IL-13⁺ was observed. Interestingly, in Zbtb10 KD condition the co-cultured T cells depicted increased expression of PD1 and LAG3, the T-cell anergic markers. Moreover, the global transcriptome analysis identified that Zbtb10 is pertinent for DC activation and its depletion in cDC1 completely shuts down their immune responses. Mechanistic analysis revealed that Zbtb10 KD enhanced the expression of NKRF (NF-κB repressing factor) leading to drastic suppression of NF-κB related genes. Zbtb10 KD abrogated p65 and RelB nuclear translocation, thereby controlling the activation and maturation of cDC1 and the ensuing adaptive T cell responses.

Porcine circovirus type 2 exploits cap to inhibit PKR activation through interaction with Hsp40

Porcine circovirus type 2 is the main pathogen of porcine circovirus disease, which has caused enormous economic losses to the pig industry worldwide. The PKR signaling pathway is important for the cellular antiviral response, but its role in the process of PCV2 infection is unknown. In this study, we first found that dsRNA was produced and that PKR was activated in PCV2 infection. However, interestingly, the activation of PKR was inhibited when the Cap protein was exogenously expressed in PAMs, and this inhibition was reversed by the expression of DNAJC7. The interaction between Cap and DNAJC7 was confirmed by laser confocal microscopy, coimmunoprecipitation and GST pull-down, and it was found that PCV2 infection or the expression of Cap protein could induce DNAJC7 to migrate to the nucleus and release P58^IPK, an inhibitor of PKR activation. Downregulating the expression of DNAJC7 by a specific inhibitor or recombinant lentivirus-mediated shRNA, inhibited the replication of the PCV2 genome and the production of virions, which was consistent with the increase of DNAJC7 expression in multiple tissues of weaned piglets infected with PCV2. These data indicate that although PKR was activated by PCV2 infection, the activation was inhibited by Cap through an interaction with DNAJC7. These results help to understand the molecular mechanism of immune escape after PCV2 infection.

Nuclear transporter karyopherin subunit alpha 3 levels modulate Porcine circovirus type 2 replication in PK-15 cells

Entering the nucleus is important for Porcine circovirus type 2 (PCV2) replication. Karyopherins (KPNs) mediate the nuclear import of many cytoplasmic proteins. Our previous study showed that KPNA3 is involved in interferon production during PCV2 infection induced by Poly I:C and ISD (Interferon stimulatory DNA). However, it remains unclear whether PCV2 replication is associated with KPNA3. In the present study, knockdown of KPNA3 promoted the replication of PCV2, whereas overexpression of KPNA3 inhibited PCV2 replication in PK-15 cells. Furthermore, KPNA3 knockdown inhibited IRF3 and reduced the expression of antiviral genes including IFN-β, ISG54, Mx1 and ISG56, while the opposite results were obtained after KPNA3 overexpression. KPNA3 knockdown also promoted p65 nuclear translocation and increased the mRNA expression of IL-10 and IL-1β. These results suggested that KPNA3 facilitates IRF3 entry into the nucleus and the production of an antiviral response, resulting in PCV2 replication inhibition and blockage of NF-κB signal activation.

Herbal extracts as antiviral agents

Phytotherapy, or herbalism, is defined as the usage of plants or herbs as medication to treat or prevent diseases in human and animals. The usage is gaining more attention among medical practitioners as well as large-scale livestock producers. A number of reports have shown the positive effects of herbal extracts as an antiviral agent used in animal feed or as a prophylaxis and remedy. Besides being a cheaper and safer alternative, the use of herbs may reduce the incidence of drug resistance and may modulate the immune system in preventing viral-related diseases. In this chapter, the antiviral effects of several herbs and their extracts against viruses in terms of the mechanism of action in targeting viral replication steps, the effects in the host and the application in animals will be discussed. The information given may aid in improving the health and increase the production of animals.

Porcine Circovirus Type 2 Induces Single Immunoglobulin Interleukin-1 Related Receptor (SIGIRR) Downregulation to Promote Interleukin-1β Upregulation in Porcine Alveolar Macrophage

Multisystemic inflammation in pigs affected by porcine circovirus type 2 (PCV2) indicates the disordered expression of inflammatory cytokines. However, the PCV2-induced expression profile of inflammation cytokines and its regulating mechanism remain poorly understood. In this study, inflammatory cytokines and receptors in porcine alveolar macrophages (PAMs) after PCV2 infection were profiled in vitro by an RT² Profiler^TM PCR array assay. The regulatory mechanism of interleukin-1β (IL-1β) expression was investigated. Results showed that 49 of 84 inflammation cytokines and receptors were differentially expressed (p < 0.05, absolute fold change ≥2) in PAMs at different stages post-PCV2 infection. Moreover, the overexpression of single-immunoglobulin interleukin-1 related receptor (SIGIRR) or the blocking of NF-κB activation by its inhibitor markedly decreased IL-1β secretion. This finding suggested that PCV2-induced overexpression of IL-1β was associated with the downregulation of SIGIRR and the activation of NF-κB. Furthermore, the excessive activity of NF-κB in SIGIRR-knockout PAMs cell line, indicating that SIGIRR negatively regulated IL-1β production by inhibiting the activation of NF-κB. Overall, PCV2-induced downregulation of SIGIRR induction of NF-κB activation is a critical process in enhancing IL-1β production in PAMs. This study may provide insights into the underlying inflammatory response that occurs in pigs following PCV2 infection.

Enterococcus faecium NCIMB 10415 administration improves the intestinal health and immunity in neonatal piglets infected by enterotoxigenic Escherichia coli K88

Background

This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB 10415 (E. faecium) on intestinal development, immunological parameters and gut microbiota of neonatal piglets challenged with enterotoxigenic Escherichia coli K88 (ETEC). A total of 96 1-day-old sow-reared piglets were randomly assigned to 2 groups, with 48 piglets in each group. The piglets were from 16 litters (6 piglets each litter), and 3 piglets each litter were allocated to the E. faecium-supplemented (PRO) group, while the other 3 piglets were allocated to the control (CON) group. After colostrum intake, piglets in the PRO group were orally administrated with 3 × 10⁹ CFU E. faecium per day for a period of one week. On day 8, one piglet per litter from each group was challenged (CON+ETEC, PRO+ETEC) or not (CON-ETEC, PRO-ETEC) with ETEC in a 2 × 2 factorial arrangement of treatments. On day 10 (2 days after challenge), blood and tissue samples were obtained from piglets.

Results

Before ETEC challenge, there were no significant differences for the average daily gain (ADG) and fecal score between the two groups of piglets. After ETEC challenge, the challenged piglets had greater fecal score compared to the non-challenged piglets, whereas E. faecium administration was able to decrease the fecal score. Piglets challenged with ETEC had shorter villous height, deeper crypt depth, and reduced number of goblet cells in the jejunum and decreased mRNA abundance of claudin-1 in the ileum, whereas increased the percentage of lymphocytes, concentrations of IL-1β in the plasma and TNF-α in the ileal mucosa, as well as increased the mRNA abundances of innate immunity-related genes in the ileum tissue. These deleterious effects caused by ETEC were partly alleviated by feeding E. faecium. In addition, piglets in PRO-ETEC group had decreased the percentage of CD8⁺ T cells of the peripheral blood when compared to those in CON-ETEC group. Moreover, E. faecium administration increased Verrucomicrobia at phylum level and decreased Bilophila at genus level.

Conclusions

These results suggest that oral administration of E. faecium alleviated the intestinal injury and diarrhea severity of neonatal piglets challenged by ETEC, partly through improving the intestinal microbiota and immune response. This offers a potential strategy of dietary intervention against intestinal impairment by ETEC in neonatal piglets.

Electronic supplementary material

The online version of this article (10.1186/s40104-019-0376-z) contains supplementary material, which is available to authorized users.

Mycoplasma hyopneumoniae Mhp597 is a cytotoxicity, inflammation and immunosuppression associated nuclease

Nucleases are ubiquitously recognized as essential proteins in mycoplasmas because these organisms lack most capacities for de novo synthesis of nucleotides. Some of these proteins were proved to be important pathogenic factors during the infection of mycoplasms. In this study, the protein Mhp597 from M. hyopneumoniae was expressed and purified in Escherichia coli. Analysis of nuclease activity showed that recombinant Mhp597 (rMhp597) was a Ca₂₊ or Mg₂₊ dependent thermostable nuclease with very high activity and neutrophil extracellular traps (NETs) induced by M. hyopneumoniae were completely degraded by this nuclease. In addition, when PK15 cells were incubated with different concentrations of rMhp597, their viability was reduced and cell apoptosis was observed in a dose-dependent manner. To further investigate the host immune system response, we report that rMhp597 up-regulated the exression of inflammatory genes showing that TLR4/MyD88/NF-κB signal pathway was involved. On the other hand, rMhp597 down-regulated the expression of type I IFN (IFN-α/β) and promoted the multiplication of porcine reproductive and respiratory syndrome virus (PRRSV). Recombinant rMhp597δ^315-377 lacking C-terminal 63 amino acids exhibited all biological functions mentioned above except for nuclease activity. In summary, Mhp597 is a dynamic secreted nuclease involved in cytotoxicity, inflammation and immunosuppression.

Molecular detection of Hsp90 inhibitor suppressing PCV2 replication in host cells

Porcine Circovirus Type 2 (PCV2) is a pathogen that has the ability to cause devastating disease manifestations in pig populations with major economic implications. Our previous research found that Hsp90 is required for PCV2 production in PK-15 and 3D4/31 cells. The aim of this study was to evaluate the effect of Hsp90 inhibitor regulating PCV2 replication and to explore its underlying mechanism. In PK-15 and 3D4/31 cells treated with 17-AAG after viral adsorption, replication of PCV2 was attenuated as assessed by quantitating the expression of viral protein. Following NF-κB activation it was observed that 24hpi with PCV2 was significantly inhibited in the presence of 17-AAG. The expression of Hsp90 associated client proteins in PCV2-infected cells were also reduced in the presence of 17-AAG. However, treatment with MG-132 failed to rescue 17-AAG mediated reduction of PCV2 production in host cells. Thus, Hsp90 regulates PCV2 by modulating cellular signaling proteins. These results highlight the importance of cellular proteins during PCV2 infection and the possibility of targeting cellular chaperones for developing new anti-rotaviral strategies.

Bacterial Clearance Is Enhanced by α2,3- and α2,6-Sialyllactose via Receptor-Mediated Endocytosis and Phagocytosis

Sialyllactose (SL) is a representative human milk oligosaccharide (HMO) of human breast milk. The roles of SL in infant brain development and immunity have been reported in previous studies.

Sialyllactose (SL) is a representative human milk oligosaccharide (HMO) of human breast milk. The roles of SL in infant brain development and immunity have been reported in previous studies. In this study, we identified the impact of SL on innate immunity. Our results showed that the administration of SL had significant efficacy on bacterial clearance in Pseudomonas aeruginosa K-infected mice. We also examined the role of SL in the human THP-1 macrophage-like cell line. SL effectively promoted receptor-mediated endocytosis and phagocytosis. Furthermore, SL accelerated the recruitment of Rac1 to the cell membrane, leading to the generation of reactive oxygen species for the elimination of phagocytosed bacteria. Our findings provide a new perspective on the role of SL in breast milk and suggest its application as a therapeutic agent to treat bacterial and viral infections.

Arsenic and/or copper caused inflammatory response via activation of inducible nitric oxide synthase pathway and triggered heat shock protein responses in testis tissues of chicken

The aim of this study is to investigate the effects of arsenic (As) and copper (Cu) on the inflammatory response, and the protective roles of heat shock proteins (Hsps) in chicken testes. Seventy-two 1-day-old male Hy-line chickens were treated with 30 mg/kg feed of arsenic trioxide (As₂O₃) and/or 300 mg/kg feed of copper sulfate (CuSO₄) for 4, 8, and 12 weeks. The histological changes, inducible nitric oxide synthase (iNOS) activity, and the expressions of Hsps and inflammatory cytokines were detected. The results showed that slight histology changes were obvious in the testis tissue exposure to treatment groups. The activity and the protein level of iNOS were increased compared to the control group. The mRNA levels of proinflammatory cytokines and inflammatory factors were increased as a whole. However, anti-inflammatory cytokines were inhibited. The mRNA and protein levels of Hsp60, Hsp70, and Hsp90 were upregulated. These results suggested that sub-chronic exposure to As and/or Cu induced testicular poisoning in chickens. Increased Hsps tried to protect chicken testis tissues from tissues damage caused by inflammation. In conclusion, testicular poisoning induced by As and/or Cu caused inflammatory response and heat shock protein response in chicken testis tissues.

Porcine circovirus type 2 increases interleukin-1beta and interleukin-10 production via the MyD88-NF-kappa B signaling pathway in porcine alveolar macrophages in vitro

Porcine alveolar macrophages (PAMs) represent the first line of defense in the porcine lung after infection with porcine circovirus type 2 (PCV2) via the respiratory tract. However, PCV2 infection impairs the microbicidal capability of PAMs and alters cytokine production and/or secretion. At present, the reason for the imbalance of cytokines has not been fully elucidated, and the regulatory mechanisms involved are unclear. In this study, we investigated the expression levels and regulation of interleukin-1beta (IL-1β) and IL-10 in PAMs following incubation with PCV2 in vitro. Levels of IL-1β and IL-10 increased in PAM supernatants, and the distribution of nuclear factor kappa B (NF-κB) p65staining in nucleus, expression of MyD88 and p-IκB in cytoplasm, and DNA-binding activity of NF-κB increased after incubation with PCV2, while p65 expression in PAM cytoplasm decreased. However, when PAMs were co-incubated with PCV2 and small interfering RNA targeting MyD88, those effects were reversed. Additionally, mRNA expression levels of Toll-like receptors (TLR)-2, -3, -4, -7, -8, and -9 increased when PAMs were incubated with PCV2. These results show that PCV2 induces increased IL-1β and IL-10 production in PAMs, and these changes in expression are related to the TLR-MyD88-NF-κB signaling pathway.

Antiviral and Immunoregulatory Role Against PCV2 in Vivo of Chinese Herbal Medicinal Ingredients

Introduction

The aim of the research was to investigate the antiviral and immunoregulatory effects of saikosaponin A, saikosaponin D, Panax notoginseng saponins, notoginsenoside R1, and anemoside B4 saponins commonly found in Chinese herbal medicines.

Material and Methods

control mice were challenged intramuscularly (im) with 0.2 mL of porcine circovirus 2 (PCV2) solution containing 10⁷ TCID₅₀ of the virus/mL. Mice of high-, middle-, and low-dose saponin groups were initially challenged im with 0.2 mL of PCV2 solution and three days later treated intraperitoneally (ip) with one of five saponins at one of three doses (10, 5, or 1 mg/kg b.w.). In the drug control group, mice were dosed ip with 10 mg/kg b.w. of a given saponin, and mice in a blank control group were administered the same volume of normal saline.

Results

The results revealed that the saponins could reduce the incidence and severity of PCV2-induced immunopathological damage, e.g. body temperature elevation, weight loss, anaemia, and internal organ swelling. In addition, it was seen that the saponins could affect the immunoglobulin levels and protein absorption.

Conclusion

The data suggested that the saponins might effectively regulate immune responses.

Lipopolysaccharide aggravated DOI-induced Tourette syndrome: elaboration for recurrence of Tourette syndrome

Tourette syndrome (TS) is a neurological disorder characterized by highest familial recurrence rate among neuropsychiatric diseases with complicated inheritance. Recurrence of Tourette syndrome was frequently observed in clinical. Unexpectedly, the mechanism of recurrence of Tourette syndrome was failure to elucidate. Here, we first shown that lipopolysaccharide(LPS) may played an important role in the recurrence of Tourette syndrome. The TS model in rats was induced by DOI (the selective 5-HT2A/2C agonist 1-(2, 5-dimethoxy-4-iodophenyl) -2- aminopropane). The rats were randomly divided into 4 groups:(1)Control;(2) Control + LPS; (2)TS; (3)TS + LPS. The results demonstrated that the LPS treatment significantly increased stereotypic score and autonomic activity. LPS treatment also significantly increased inflammatory cytokines such as interleukin-6 (IL-6), interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) in serum and striatum. Also, highly expressed TLR4, MyD88, P-NF-κBp65, P-IκBα in TS rats were increased respectively by LPS treatment as indicted in western blot analysis and immunohistochemistry analysis. Thus, it was supposed that lipopolysaccharide(LPS) may played an important role in the recurrence of Tourette syndrome and its mechanism was related to TLR/NF-κB pathway.

Effects of dietary live yeast supplementation on growth performance, diarrhoea severity, intestinal permeability and immunological parameters of weaned piglets challenged with enterotoxigenic Escherichia coli K88

This study aimed to investigate the effects of dietary live yeast (LY) supplementation on growth, intestinal permeability and immunological parameters of piglets challenged with enterotoxigenic Escherichia coli K88 (ETEC). Piglets weaned at 21 d were allocated into three treatments with six pens and six piglets per pen, receiving the control diet (CON), diets supplemented with antibiotics plus zinc oxide (ANT–ZnO) and LY (Saccharomyces cerevisiae strain CNCM I-4407), respectively, for a period of 2 weeks. On day 8, thirty-six piglets were selected as control without ETEC (CON), CON–ETEC, ANT–ZnO–ETEC and LY–ETEC groups challenged with ETEC until day 10 for sample collections. Piglets fed ANT–ZnO diet had the highest average daily gain and average daily feed intake (P<0·05) during the 1st week, but ADG of piglets fed the ANT–ZnO diet was similar as piglets fed LY diet during the second week. Piglets with LY–ETEC or ANT–ZnO–ETEC had markedly lower diarrhoea score (P<0·05) than piglets with CON–ETEC during the 24 h after ETEC challenge. Relative to piglets with CON, the counts of E. coli, urinary ratio of lactulose to mannitol, plasma IL-6 concentration, mRNA abundances of innate immunity-related genes in ileum and mesenteric lymph node tissues were increased (P<0·05), whereas the villous height of jejunum and relative protein expression of ileum claudin-1 were decreased (P<0·05) in piglets with CON–ETEC; however, these parameters did not markedly change in piglets with LY–ETEC or ANT–ZnO–ETEC. In summary, dietary LY supplementation could alleviate the severity of diarrhoea in piglets with ETEC, which may be associated with the improved permeability, innate immunity and bacterial profile.

The role of TLRs in cervical cancer with HPV infection: a review

The main cause of cervical cancer is persistent infection with high-risk human papilloma virus (HR-HPV), but not all human papilloma virus (HPV) infections lead to cervical cancer. The key factors that determine the outcome of HPV infection remain poorly understood, and how the host immune system protects against HPV infection is unclear. Toll-like receptors (TLRs) are a group of pattern recognition receptors present in the cytoplasm and cell membrane, and can specifically recognize pathogen-associated molecular patterns. As the key molecules of innate and acquired immunity, TLRs not only play important roles in the immune defense against infectious diseases, but also are involved in the occurrence and development of a variety of malignant tumors. In cervical cancer caused by HR-HPV infection, TLRs have been found to regulate the local immune microenvironment. The role of TLRs in HR-HPV infection and HPV-induced cervical cancer and its relationship with HPV vaccine are reviewed in this article.

Vimentin modulates infectious porcine circovirus type 2 in PK-15 cells

Porcine circovirus type 2 (PCV2) is the pathogen that causes postweaning multisystemic wasting syndrome, which leads to significant economic losses for swine farms worldwide. However, the infection mechanism of PCV2 is not completely understood yet. Vimentin is a part of the cytoskeleton network and plays an important role in several virus infections. It is not clear whether vimentin has a role in PCV2 infection nor how it affects PCV2 infection. In this study, the function of vimentin in PK-15 cells infected with PCV2 has been elucidated. We found that vimentin had a restrictive effect on the replication of PCV2 in PK-15 cells. Overexpression of vimentin by transferred pCAGGS-vimentin and down-regulation by the respective scrambled small interfering RNA showed that vimentin restricted the replication and virion production of PCV2. A special interaction between vimentin and PCV2 Cap protein was observed using laser confocal microscopy and immunoprecipitation assay. Moreover, overexpression of vimentin could decrease NF-κB activity and increase PCV2-induced caspase-3 activity in PK-15 cells. These data suggest that vimentin is involved in the replication of PCV2 and has a restrictive effect on it, which is helpful in the study of the replication mechanism of PCV2.

RIG-1 and MDA-5 signaling pathways contribute to IFN-β production and viral replication in porcine circovirus virus type 2-infected PK-15 cells in vitro

Type I Interferons (IFNs) is known for its antiviral activity; however, it is surprising that in vitro treatment of IFN-α and IFN-γ enhanced the replication of porcine circovirus type 2 (PCV2), indicating a complex relationship between interferon and PCV2. To date, it remains poorly understood how the interferon is produced during PCV2 infection and whether the interferon induced by PCV2 itself can promote viral replication. In this study, PCV2 induced the up-regulation of IFN-β in PK-15 cells, while treatment of PCV2-infected cells with the interferon regulatory factor-3 (IRF3) inhibitor, BX795, decreased the expression of IFN-β, whereas treatment with the nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) inhibitor, BAY11-7082, did not. These findings indicate that PCV2 can induce IFN-β production via the IRF3-mediated rather than the NF-κB-mediated signal pathway. Moreover, PCV2 increased the protein expression levels of phosphorylation-IRF3 (p-IRF3), mitochondria antiviral-signaling protein (MAVS), retinoic acid-inducible gene I (RIG-1) and melanoma differentiation-associated protein 5 (MDA-5), and the knockdown of RIG-1 and MDA-5 decreased the expression level of IFN-β in PK-15 cells. Therefore, PCV2 induces IFN-β production via the RIG-1/MDA-5/MAVS/IRF signaling pathway. Furthermore, the PCV2 load and PCV2 infectivity decreased after knockdown of RIG-1 and MDA-5, indicating that RIG-1 and MDA-5 signaling pathways contribute to PCV2 replication. In conclusion, PCV2 induces the production of IFN-β via the RIG-1 and MDA-5 signaling pathways, and the IFN-β produced during PCV2 infection facilitates viral replication. These results will help us further understand the pathogenic mechanisms of PCV2.

Porcine circovirus type 2 activates PI3K/Akt and p38 MAPK pathways to promote interleukin-10 production in macrophages via Cap interaction of gC1qR

Porcine circovirus type 2 (PCV2) infection caused PCV2-associated diseases (PCVAD) is one of the major emerging immunosuppression diseases in pig industry. In this study, we investigated how PCV2 inoculation increases interleukin (IL)-10 expression in porcine alveolar macrophages (PAMs). PCV2 inoculation significantly upregulated IL-10 expression compared with PCV1. Upon initial PCV2 inoculation, PI3K/Akt cooperated with NF-κB pathways to promote IL-10 transcription via p50, CREB and Ap1 transcription factors, whereas inhibition of PI3K/Akt activation blocked Ap1 and CREB binding to the il10 promoter, and decreased the binding level of NF-κB1 p50 with il10 promoter, leading to great reduction in early IL-10 transcription. In the later phase of inoculation, PCV2 further activated p38 MAPK and ERK pathways to enhance IL-10 production by promoting Sp1 binding to the il10 promoter. For PCV2-induced IL-10 production in macrophages, PCV2 capsid protein Cap, but not the replicase Rep or ORF3, was the critical component. Cap activated PI3K/Akt, p38 MAPK, and ERK signaling pathways to enhance IL-10 expression. In the whole process, gC1qR mediated PCV2-induced PI3K/Akt and p38 MAPK activation to enhance IL-10 induction by interaction with Cap. Depletion of gC1qR blocked PI3K/Akt and p38 MAPK activation, resulting in significant decrease in IL-10 production in PCV2-inoculated cells. Thus, gC1qR might be a critical functional receptor for PCV2-induced IL-10 production. Taken together, these data demonstrated that Cap protein binding with host gC1qR induction of PI3K/Akt and p38 MAPK signalings activation is a critical process in enhancing PCV2-induced IL-10 production in porcine alveolar macrophages.

Matrine displayed antiviral activity in porcine alveolar macrophages co-infected by porcine reproductive and respiratory syndrome virus and porcine circovirus type 2

The co-infection of porcine reproductive respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2) is quite common in clinical settings and no effective treatment to the co-infection is available. In this study, we established the porcine alveolar macrophages (PAM) cells model co-infected with PRRSV/PCV2 with modification in vitro, and investigated the antiviral activity of Matrine on this cell model and further evaluated the effect of Matrine on virus-induced TLR3,4/NF-κB/TNF-α pathway. The results demonstrated PAM cells inoculated with PRRSV followed by PCV2 2 h later enhanced PRRSV and PCV2 replications. Matrine treatment suppressed both PRRSV and PCV2 infection at 12 h post infection. Furthermore, PRRSV/PCV2 co- infection induced IκBα degradation and phosphorylation as well as the translocation of NF-κB from the cytoplasm to the nucleus indicating that PRRSV/PCV2 co-infection induced NF-κB activation. Matrine treatment significantly down-regulated the expression of TLR3, TLR4 and TNF-α although it, to some extent, suppressed p-IκBα expression, suggesting that TLR3,4/NF-κB/TNF-α pathway play an important role of Matrine in combating PRRSV/PCV2 co-infection. It is concluded that Matrine possesses activity against PRRSV/PCV2 co-infection in vitro and suppression of the TLR3,4/NF-κB/TNF-α pathway as an important underlying molecular mechanism. These findings warrant Matrine to be further explored for its antiviral activity in clinical settings.

Synergy of TLR3 and 7 ligands significantly enhances function of DCs to present inactivated PRRSV antigen through TRIF/MyD88-NF-κB signaling pathway

PRRS is one of the most important diseases in swine industry. Current PRRS inactivated vaccine provides only a limited protection and cannot induce sufficient cell-mediated immune responses. In this study, we first found that the mRNA and protein levels of Th1-type cytokines (IFN-γ, IL-12) and Th2-type cytokines (IL-6, IL-10) were significantly increased through TRIF/MyD88-NF-κB signaling pathway when porcine peripheral blood monocyte-derived dendritic cells (MoDCs) were treated with poly (I: C) of TLR3 ligand and imiquimod of TLR7 ligand, along with inactivated PRRSV antigen. Meanwhile, the ability of catching PRRSV antigen was also significantly enhanced. In mice experiment, it was found that the PRRSV-specific T lymphocyte proliferation, the percentages of CD4⁺, CD8⁺ T lymphocytes and PRRSV-specific CD3⁺ T cells producing IFN-γ and IL-4, the levels of Th1- and Th2-type cytokines and the titers of neutralization antibody were significantly enhanced in poly (I: C), imiquimod along with inactivated PRRSV group. Taken together, results of our experiments described for the first time that synergy of TLR3 and 7 ligands could significantly enhance the function of DCs to present inactivated PRRSV antigen through TRIF/MyD88-NF-κB signaling pathway and be used as adjuvant candidate for the development of novel PRRS inactivated vaccine.

Arsenic Trioxide Attenuates NF-κB and Cytokine mRNA Levels in the Livers of Cocks

Arsenic (As) is a trace element widely found in nature. It exists in several forms, including organic arsenic, inorganic arsenic, and trivalent arsenic, the most toxic. Arsenic trioxide (As2O3) is widespread in nature. This form tends to accumulate in animals and humans and therefore has a potential harm for them. Cytokines play essential roles in the immune response and inflammation. Although the importance of cytokines in the responses to arsenic exposure has been demonstrated in many types of mammals, the function of these in poultry, especially in chickens, remains unclear. The purpose of the present study was to examine the effect of As2O3 exposure on cytokines in cock livers. In this study, 72 1-day-old male Hy-line cocks were randomly divided into four groups including the control group, low-As group, middle-As group, and high-As group. The livers were collected on days 30, 60, and 90 of the experiment. The levels of nuclear factor-kappa B (NF-κB), tumor necrosis factor-alpha (TNF-α), interleukin-4 (IL-4), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-12 beta (IL-12β), and interleukin-1 beta (IL-1β) mRNA in the livers of the cocks were measured using real-time PCR. The results showed that the expression levels of IL-6, IL-8, TNF-α, and NF-κB which seemed to be a critical mediator in the inflammatory response tended to increase in the birds chronically treated with As2O3. However, the mRNA expression levels of IL-4, IL-12β, and IL-1β were decreased in the experiment. The information regarding the effects of As2O3 on cytokine mRNA expression generated in this study will be important information for arsenic toxicology evaluation.

Flavanol-Enriched Cocoa Powder Alters the Intestinal Microbiota, Tissue and Fluid Metabolite Profiles, and Intestinal Gene Expression in Pigs

BACKGROUND

Consumption of cocoa-derived polyphenols has been associated with several health benefits; however, their effects on the intestinal microbiome and related features of host intestinal health are not adequately understood.

OBJECTIVE

The objective of this study was to determine the effects of eating flavanol-enriched cocoa powder on the composition of the gut microbiota, tissue metabolite profiles, and intestinal immune status.

METHODS

Male pigs (5 mo old, 28 kg mean body weight) were supplemented with 0, 2.5, 10, or 20 g flavanol-enriched cocoa powder/d for 27 d. Metabolites in serum, urine, the proximal colon contents, liver, and adipose tissue; bacterial abundance in the intestinal contents and feces; and intestinal tissue gene expression of inflammatory markers and Toll-like receptors (TLRs) were then determined.

RESULTS

O-methyl-epicatechin-glucuronide conjugates dose-dependently increased (P< 0.01) in the urine (35- to 204-fold), serum (6- to 186-fold), and adipose tissue (34- to 1144-fold) of pigs fed cocoa powder. The concentration of 3-hydroxyphenylpropionic acid isomers in urine decreased as the dose of cocoa powder fed to pigs increased (75-85%,P< 0.05). Compared with the unsupplemented pigs, the abundance ofLactobacillusspecies was greater in the feces (7-fold,P= 0.005) and that ofBifidobacteriumspecies was greater in the proximal colon contents (9-fold,P= 0.01) in pigs fed only 20 or 10 g cocoa powder/d, respectively. Moreover, consumption of cocoa powder reducedTLR9gene expression in ileal Peyer's patches (67-80%,P< 0.05) and mesenteric lymph nodes (43-71%,P< 0.05) of pigs fed 2.5-20 g cocoa powder/d compared with pigs not supplemented with cocoa powder.

CONCLUSION

This study demonstrates that consumption of cocoa powder by pigs can contribute to gut health by enhancing the abundance ofLactobacillusandBifidobacteriumspecies and modulating markers of localized intestinal immunity.

Infection of porcine circovirus 2 (PCV2) in intestinal porcine epithelial cell line (IPEC-J2) and interaction between PCV2 and IPEC-J2 microfilaments

BACKGROUND

Porcine circovirus-associated disease (PCVAD) is caused by a small pathogenic DNA virus, Porcine circovirus type 2 (PCV2), and is responsible for severe economic losses. PCV2-associated enteritis appears to be a distinct clinical manifestation of PCV2. Most studies of swine enteritis have been performed in animal infection models, but none have been conducted in vitro using cell lines of porcine intestinal origin. An in vitro system would be particularly useful for investigating microfilaments, which are likely to be involved in every stage of the viral lifecycle.

METHODS

We confirmed that PCV2 infects the intestinal porcine epithelial cell line IPEC-J2 by means of indirect immunofluorescence, transmission electron microscopy, flow cytometry and qRT-PCR. PCV2 influence on microfilaments in IPEC-J2 cells was detected by fluorescence microscopy and flow cytometry. We used Cytochalasin D or Cucurbitacin E to reorganize microfilaments, and observed changes in PCV2 invasion, replication and release in IPEC-J2 cells by qRT-PCR.

RESULTS

PCV2 infection changes the ultrastructure of IPEC-J2 cells. PCV2 copy number in IPEC-J2 cells shows a rising trend as infection proceeds. Microfilaments are polymerized at 1 h p.i., but densely packed actin stress fibres are disrupted and total F-actin increases at 24, 48 and 72 h p.i. After Cytochalasin D treatment, invasion of PCV2 is suppressed, while invasion is facilitated by Cucurbitacin E. The microfilament drugs have opposite effects on viral release.

CONCLUSION

PCV2 infects and proliferates in IPEC-J2 cells, demonstrating that IPEC-J2 cells can serve as a cell intestinal infection model for PCV2 pathogenesis. Furthermore, PCV2 rearranges IPEC-J2 microfilaments and increases the quantity of F-actin. Actin polymerization may facilitate the invasion of PCV2 in IPEC-J2 cells and the dissolution of cortical actin may promote PCV2 egress.