TLR2/MyD88/NF-κB signaling pathway regulates IL-1β production in DF-1 cells exposed to Mycoplasma gallisepticum LAMPs

Immune Evasion of Mycoplasma gallisepticum: An Overview

Mycoplasma gallisepticum is one of the smallest self-replicating organisms. It causes chronic respiratory disease, leading to significant economic losses in poultry industry. Following M. gallisepticum invasion, the pathogen can persist in the host owing to its immune evasion, resulting in long-term chronic infection. The strategies of immune evasion by mycoplasmas are very complex and recent research has unraveled these sophisticated mechanisms. The antigens of M. gallisepticum exhibit high-frequency changes in size and expression cycle, allowing them to evade the activation of the host humoral immune response. M. gallisepticum can invade non-phagocytic chicken cells and also regulate microRNAs to modulate cell proliferation, inflammation, and apoptosis in tracheal epithelial cells during the disease process. M. gallisepticum has been shown to transiently activate the inflammatory response and then inhibit it by suppressing key inflammatory mediators, avoiding being cleared. The regulation and activation of immune cells are important for host response against mycoplasma infection. However, M. gallisepticum has been shown to interfere with the functions of macrophages and lymphocytes, compromising their defense capabilities. In addition, the pathogen can cause immunological damage to organs by inducing an inflammatory response, cell apoptosis, and oxidative stress, leading to immunosuppression in the host. This review comprehensively summarizes these evasion tactics employed by M. gallisepticum, providing valuable insights into better prevention and control of mycoplasma infection.

Puerarin Alleviates Oxidized Oil-Induced Oxidative Injury and Inflammation via Inhibition of the Nrf2/Keap1 and HMGB1/TLR4/MAPK Signaling Pathways: An Investigation in a Chicken Model

SCOPE

Puerarin has possessed a wide range of pharmacological activities. However, little is known about the protective effects of puerarin on the oxidized oil-induced injury. Here, the antioxidant and anti-inflammatory effects of puerarin are described using a chicken model.

METHODS AND RESULTS

A total of 360 broilers are arranged in four treatments. Diets include two types of soybean oil (fresh or oxidized) and two levels of puerarin (0 or 750 mg kg-1 ). Results show that puerarin alleviates oxidized soybean oil-induced hepatic and thymic oxidative injury. This effect is observed by increasing the SOD activity and the expressions of Nrf2 signaling pathway-related genes and reducing the MDA content in the liver and thymus. Moreover, puerarin supplementation decreases the concentrations and mRNA levels of pro-inflammatory factors in the liver and thymus. The potential mechanism responsible for this is the decrease in the mRNA or protein levels of HMGB1, TLR4, MyD88, and p65 in the liver or thymus. Western blotting results indicate that puerarin also decreases the phosphorylation of JNK1/2, ERK1/2, and p38 in the liver and thymus.

CONCLUSION

This study demonstrates puerarin may be a potential nutrient supplement in the treatment of oxidized oil-induced damage, and the Nrf2/Keap1 and HMGB1/TLR4/MAPK signaling pathways might be its important target.

Conserved Domains in Variable Surface Lipoproteins A-G of Mycoplasma hyorhinis May Serve as Probable Multi-Epitope Candidate Vaccine: Computational Reverse Vaccinology Approach

Mycoplasma hyorhinis (M. hyorhinis) is responsible for infections in the swine population. Such infections are usually cured by using antimicrobials and lead to develop resistance. Until now, there has been no effective vaccine to eradicate the disease. This study used conserved domains found in seven members of the variable lipoprotein (VlpA-G) family in order to design a multi-epitope candidate vaccine (MEV) against M. hyorhinis. The immunoinformatics approach was followed to predict epitopes, and a vaccine construct consisting of an adjuvant, two B cell epitopes, two HTL epitopes, and one CTL epitope was designed. The suitability of the vaccine construct was identified by its non-allergen, non-toxic, and antigenic nature. A molecular dynamic simulation was executed to assess the stability of the TLR2 docked structure. An immune simulation showed a high immune response toward the antigen. The protein sequence was reverse-translated, and codons were optimized to gain a high expression level in E. coli. The proposed vaccine construct may be a candidate for a multi-epitope vaccine. Experimental validation is required in future to test the safety and efficacy of the hypothetical candidate vaccine.

The Activation of the RIG-I/MDA5 Signaling Pathway upon Influenza D Virus Infection Impairs the Pulmonary Proinflammatory Response Triggered by Mycoplasma bovis Superinfection

Concurrent infections with multiple pathogens are often described in cattle with respiratory illness. However, how the host-pathogen interactions influence the clinical outcome has been only partially explored in this species. Influenza D virus (IDV) was discovered in 2011. Since then, IDV has been detected worldwide in different hosts. A significant association between IDV and bacterial pathogens in sick cattle was shown in epidemiological studies, especially with Mycoplasma bovis. In an experimental challenge, IDV aggravated M. bovis-induced pneumonia. However, the mechanisms through which IDV drives an increased susceptibility to bacterial superinfections remain unknown. Here, we used the organotypic lung model precision-cut lung slices to study the interplay between IDV and M. bovis coinfection. Our results show that a primary IDV infection promotes M. bovis superinfection by increasing the bacterial replication and the ultrastructural damages in lung pneumocytes. In our model, IDV impaired the innate immune response triggered by M. bovis by decreasing the expression of several proinflammatory cytokines and chemokines that are important for immune cell recruitment and the bacterial clearance. Stimulations with agonists of cytosolic helicases and Toll-like receptors (TLRs) revealed that a primary activation of RIG-I/MDA5 desensitizes the TLR2 activation, similar to what was observed with IDV infection. The cross talk between these two pattern recognition receptors leads to a nonadditive response, which alters the TLR2-mediated cascade that controls the bacterial infection. These results highlight innate immune mechanisms that were not described for cattle so far and improve our understanding of the bovine host-microbe interactions and IDV pathogenesis. IMPORTANCE Since the spread of the respiratory influenza D virus (IDV) infection to the cattle population, the question about the impact of this virus on bovine respiratory disease (BRD) remains still unanswered. Animals affected by BRD are often coinfected with multiple pathogens, especially viruses and bacteria. In particular, viruses are suspected to enhance secondary bacterial superinfections. Here, we use an ex vivo model of lung tissue to study the effects of IDV infection on bacterial superinfections. Our results show that IDV increases the susceptibility to the respiratory pathogen Mycoplasma bovis. In particular, IDV seems to activate immune pathways that inhibit the innate immune response against the bacteria. This may allow M. bovis to increase its proliferation and to delay its clearance from lung tissue. These results suggest that IDV could have a negative impact on the respiratory pathology of cattle.

Dietary puerarin supplementation improves immune function in the small intestines of oxidized oil-challenged broilers

Puerarin has possessed a wide range of pharmacological activities. However, little is known about the protective effects of puerarin on the oxidized oil-induced injury. Here, we describe the anti-inflammatory effects of puerarin in chickens. A total of 360 broilers were arranged in four treatments. Diets included two types of soybean oil (fresh or oxidized) and two levels of puerarin (0 or 750 mg/kg). Results showed that puerarin alleviated oxidized soybean oil-induced intestinal immune injury by decreasing the expressions of HSP and pro-inflammatory factor (P < 0.05) and enhancing the mRNA levels of anti-inflammatory factor and CATH-1 (P < 0.05) in broilers. Moreover, puerarin supplementation decreased the mRNA abundances of TLR4 and MyD88 (P < 0.05) and upregulated the expressions of A20 and SOCS-1 (P < 0.05) in the small intestine of oxidized soybean oil-challenged broilers. Collectively, this study demonstrates puerarin may be a potential nutrient supplement in the treatment of oxidized oil-induced damage in poultry.

Heterologous Expression, Purification, and Immunomodulatory Effects of Recombinant Lipoprotein GUDIV-103 Isolated from Ureaplasma diversum

Ureaplasma diversum is a bacterial pathogen that infects cattle and can cause severe inflammation of the genital and reproductive systems. Lipid-associated membrane proteins (LAMPs), including GUDIV-103, are the main virulence factors in this bacterium. In this study, we heterologously expressed recombinant GUDIV-103 (rGUDIV-103) in Escherichia coli, purified it, and evaluated its immunological reactivity and immunomodulatory effects in bovine peripheral blood mononuclear cells (PBMCs). Samples from rabbits inoculated with purified rGUDIV-103 were analysed using indirect enzyme-linked immunosorbent assay and dot blotting to confirm polyclonal antibody production and assess kinetics, respectively. The expression of this lipoprotein in field isolates was confirmed via Western blotting with anti-rGUDIV-103 serum and hydrophobic or hydrophilic proteins from 42 U. diversum strains. Moreover, the antibodies produced against the U. diversum ATCC 49783 strain recognised rGUDIV-103. The mitogenic potential of rGUDIV-103 was evaluated using a lymphoproliferation assay in 5(6)-carboxyfluorescein diacetate succinimidyl ester−labelled bovine PBMCs, where it induced lymphocyte proliferation. Quantitative polymerase chain reaction analysis revealed that the expression of interleukin-1β, toll-like receptor (TLR)-α, TLR2, TLR4, inducible nitric oxide synthase, and caspase-3−encoding genes increased more in rGUDIV-103−treated PBMCs than in untreated cells (p < 0.05). Treating PBMCs with rGUDIV-103 increased nitric oxide and hydrogen peroxide levels. The antigenic and immunogenic properties of rGUDIV-103 suggested its suitability for immunobiological application.

Pistachio hull polysaccharide protects Nile tilapia against LPS-induced excessive inflammatory responses and oxidative stress, possibly via TLR2 and Nrf2 signaling pathways

Polysaccharides are polymeric carbohydrates found in living organisms, which have several physiological functions. In the present study, Nile tilapia (Oreochromis niloticus) were fed diets containing three levels (0%, 0.2%, and 0.6%) of Pistacia vera hull polysaccharide (PHP) for 45 days and then injected with PBS or bacterial lipopolysaccharide (LPS). Before the LPS challenge, Nile tilapia fed 0.2% and 0.6% PHP showed significantly increased mean final weight and weight gain compared to those received 0% PHP. The specific growth rate and feed conversion ratio were significantly improved in the treatment fed 0.6% PHP compared to the remaining groups. After LPS challenge, the activities of liver antioxidant enzymes, including superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase exhibited the highest values in the 0.6% PHP group. Malondialdehyde (MDA) levels were significantly augmented in the model (fed 0% PHP diet and injected with LPS) and 0.2% PHP groups compared to the control. However, MDA showed decreased levels in the 0.6% PHP group. LPS induced higher mRNA and/or protein levels of Toll-like receptor 2 (TLR2), nuclear factor kappa B (NF-κB), myeloid differentiation primary response protein 88 (Myd88), tumor necrosis factor α (TNF-α), interleukin 1β (IL-1β), and interferon γ (IFN-γ) in Nile tilapia liver. However, PHP administration significantly upregulated the expression of interleukin 10 (IL-10), nuclear erythroid 2-related factor 2 (Nrf2), SOD, and CAT, but markedly suppressed TLR2, NF-κB, Myd88, and pro-inflammatory cytokine expression and/or production in the liver. The findings of the current study indicated that PHP has positive effects on growth performance, immune gene-related expression, and antioxidative activities. We can conclude that PHP can attenuate LPS-induced oxidative stress and inflammatory responses in vivo, possibly via induction of Nrf2 and blockade of TLR2/Myd88/NF-κB pathways in Nile tilapia.

Methylsulfonylmethane ameliorates inflammation via NF-κB and ERK/JNK-MAPK signaling pathway in chicken trachea and HD11 cells during Mycoplasma gallisepticum infection

Mycoplasma gallisepticum (MG) is an avian pathogen that commonly causes respiratory diseases in poultry. Methylsulfonylmethane (MSM) is a sulfur-containing natural compound that could alleviate inflammatory injury through its excellent anti-inflammatory and antioxidant properties. However, it is still unclear whether MSM prevents MG infection. The purpose of this study is to determine whether MSM has mitigative effects on MG-induced inflammatory injury in chicken and chicken like macrophages (HD11 cells). In this research, White Leghorn chickens and HD11 cells were used to build the MG-infection model. Besides, the protective effects of MSM against MG infection were evaluated by detecting MG colonization, histopathological changes, oxidative stress and inflammatory injury of trachea, and HD11 cells. The results revealed that MG infection induced inflammatory injury and oxidative stress in trachea and HD11 cells. However, MSM treatment significantly ameliorated oxidative stress, partially alleviated the abnormal morphological changes and reduced MG colonization under MG infection. Moreover, MSM reduced the mRNA expression of proinflammatory cytokines-related genes and decreased the number of death cells under MG infection. Importantly, the protective effects of MSM were associated with suppression of nuclear factor-kappa B (NF-κB) and extracellular signal-related kinases (ERK)/Jun amino terminal kinases (JNK)-mitogen-activated protein kinases (MAPK) pathway in trachea and HD11 cells. These results proved that MSM has protective effects on MG-induced inflammation in chicken, and supplied a better strategy for the protective intervention of this disease.

Exosomal miR-181a-5p reduce Mycoplasma gallisepticum (HS strain) infection in chicken by targeting PPM1B and activating the TLR2-mediated MyD88/NF-κB signaling pathway

Mycoplasma gallisepticum (MG) is one of the most important pathogens that causes chronic respiratory disease (CRD) in chickens. Exosomes secreted from cells have been well demonstrated to deliver miRNAs to recipient cells to modulate cellular functions. The purpose of this study is to explore the underlying functions and mechanisms of exosomal miR-181a-5p in MG-HS infection. In this study, we found that miR-181a-5p expression in vivo and in vitro was significantly up-regulated after MG-HS infection. It was also upregulated in exosomes, which were derived from MG-HS-infected type-II pneumocytes cells (CP-II). In addition, exosomes secreted by MG-HS-infected CP-II were able to transfer miR-181a-5p to recipient chicken embryo fibroblast cells (DF-1), resulting in a significant upregulation of miR-181a-5p expression in recipient DF-1 cells. We further identified that Mg²⁺/Mn²⁺-dependent protein phosphatase 1B (PPM1B) was the target gene of miR-181a-5p. Overexpression of miR-181a-5p or knockdown of PPM1B activated the nuclear factor-κB (NF-κB) signaling pathway, whereas inhibition of miR-181a-5p and overexpression of PPM1B led to the opposite results. Besides, up-regulation of miR-181a-5p significantly increased the expression of toll-like receptor 2 (TLR2), myeloid differentiation factor 88 (MyD88), tumor necrosis factors alpha (TNF-α) and interleukin-1β (IL-1β), whereas inhibition of miR-181a-5p showed a contrary result. Up-regulation of miR-181a-5p promoted cell proliferation, cell cycle progression and inhibited apoptosis to resist MG-HS infection. Moreover, overexpression of miR-181a-5p significantly negative regulated the expression of Mycoplasma gallisepticum adhesin protein (pMGA1.2) by directly inhibiting PPM1B. Thus, we concluded that exosomal miR-181a-5p from CP-II cells activated the TLR2-mediated MyD88/NF-κB signaling pathways by directly targeting PPM1B to promote the expression of pro-inflammatory cytokines for defending against MG-HS infection in recipient DF-1 cells.

A Review of Ureaplasma diversum: A Representative of the Mollicute Class Associated With Reproductive and Respiratory Disorders in Cattle

The Mollicutes class encompasses wall-less microbes with a reduced genome. They may infect plants, insects, humans, and animals including those on farms and in livestock. Ureaplasma diversum is a mollicute associated with decreased reproduction mainly in the conception rate in cattle, as well as weight loss and decreased quality in milk production. Therefore, U. diversum infection contributes to important economic losses, mainly in large cattle-producing countries such as the United States, China, Brazil, and India. The characteristics of Mollicutes, virulence, and pathogenic variations make it difficult to control their infections. Genomic analysis, prevalence studies, and immunomodulation assays help better understand the pathogenesis of bovine ureaplasma. Here we present the main features of transmission, virulence, immune response, and pathogenesis of U. diversum in bovines.

Redox Homeostasis in Poultry: Regulatory Roles of NF-κB

Redox biology is a very quickly developing area of modern biological sciences, and roles of redox homeostasis in health and disease have recently received tremendous attention. There are a range of redox pairs in the cells/tissues responsible for redox homeostasis maintenance/regulation. In general, all redox elements are interconnected and regulated by various means, including antioxidant and vitagene networks. The redox status is responsible for maintenance of cell signaling and cell stress adaptation. Physiological roles of redox homeostasis maintenance in avian species, including poultry, have received limited attention and are poorly characterized. However, for the last 5 years, this topic attracted much attention, and a range of publications covered some related aspects. In fact, transcription factor Nrf2 was shown to be a master regulator of antioxidant defenses via activation of various vitagenes and other protective molecules to maintain redox homeostasis in cells/tissues. It was shown that Nrf2 is closely related to another transcription factor, namely, NF-κB, responsible for control of inflammation; however, its roles in poultry have not yet been characterized. Therefore, the aim of this review is to describe a current view on NF-κB functioning in poultry with a specific emphasis to its nutritional modulation under various stress conditions. In particular, on the one hand, it has been shown that, in many stress conditions in poultry, NF-κB activation can lead to increased synthesis of proinflammatory cytokines leading to systemic inflammation. On the other hand, there are a range of nutrients/supplements that can downregulate NF-κB and decrease the negative consequences of stress-related disturbances in redox homeostasis. In general, vitagene-NF-κB interactions in relation to redox balance homeostasis, immunity, and gut health in poultry production await further research.

Baicalin ameliorates Mycoplasma gallisepticum-induced lung inflammation in chicken by inhibiting TLR6-mediated NF-κB signalling

1. Mycoplasma gallisepticum (MG) causes severe lung inflammation and cell damage by activating toll-like receptor (TLR) signalling, the nuclear factor-kappaB (NF-κB) pathway and pro-inflammatory cytokine gene expression. Baicalin (BA) is a flavonoid extracted from Scutellaria baicalensis, which possesses anti-inflammatory and anti-bacterial properties. This study investigated the effect of BA in MG-induced lung inflammation and its potential mechanism in MG-infected chicken embryo lungs and DF-1 cells.2. The histopathological examination result showed that BA treatment alleviated MG-induced lung pathological changes. In addition, CCK-8 and cell cycle assays showed that BA treatment inhibited MG-induced cell proliferation and cell cycle progression in DF-1 cells.3. The ELISA and RT-qPCR results demonstrated that BA treatment decreased the expression of interleukin-1beta (IL-1β), IL-6, and tumour necrosis factor-alpha (TNF-α) both in MG-infected chicken embryo lungs and DF-1 cells.4. The results revealed that BA inhibited mRNA expression levels of toll-like receptor-6 (TLR6), myeloid differentiation primary response gene-88 (MyD88) and nuclear factor-κB (NF-κB), and the nuclear translocation of NF-κB-p655. In conclusion, the results showed that BA has a protective effect against MG-induced lung inflammation in chicken by inhibiting the TLR6-mediated NF-κB signalling.

Polydatin attenuates Mycoplasma gallisepticum (HS strain)-induced inflammation injury via inhibiting the TLR6/ MyD88/NF-κB pathway

Mycoplasma gallisepticum (MG) infection is the main cause of chronic respiratory disease (CRD) characterized by severe respiratory inflammation in chickens. Polydatin (PD) is a resveratrol glycoside isolated from Polygonum cuspidatum, which has prominent anti-inflammatory effect. The purpose of this study was to investigate the therapeutic effect of PD against MG-induced inflammation in chicken and its underlying mechanism. Histopathological analysis showed that PD treatment (15, 30, and 45 mg/kg) apparently alleviated MG-induced pathological changes of chicken embryonic lung. In chicken embryo fibroblast (DF-1) cells, PD treatment (15, 30, and 60 μg/mL) could effectively suppress MG propagation, promote MG-infected cell proliferation and cell cycle progress, and inhibit MG-induced cell apoptosis. ELISA and qPCR assays showed that PD treatment significantly suppressed the expression of interleukin-6 (IL-6), IL-1β and tumor necrosis factor-α (TNF-α) induced by MG both in vivo and in vitro. Besides, molecular studies indicated that the MG-induced levels of toll-like receptor-6 TLR6, myeloid differentiation-88 (MyD88) and nuclear factor κB (NF-κB) were significantly decreased by PD treatment. Moreover, immunofluorescence analysis showed that PD treatment restrained the MG-induced NF-κB-p65 nuclear translocation. Taken together, these results indicate the protective effects of PD against MG-induced inflammation injury in chicken were mainly by inhibiting the TLR6/MyD88/NF-κB pathway.

Puerarin inhibits Mycoplasma gallisepticum (MG-HS)-induced inflammation and apoptosis via suppressing the TLR6/MyD88/NF-κB signal pathway in chicken

Mycoplasma gallisepticum (MG) is the primary etiological agent of chicken chronic respiratory disease (CRD), which mainly causes inflammatory damage of the host respiratory system. Previous studies suggest that puerarin (PUE) plays a pivotal regulatory role in inflammatory diseases, whereas the impacts of PUE on MG-induced inflammation remain unclear. This study investigated the effects of PUE on MG-HS infection in vitro and in vivo and indicated its potential therapeutic and preventive value. Experimental results showed that PUE significantly suppressed pMGA1.2 expression, promoted MG-infected cell proliferation and cell cycle process by reducing apoptosis. Histopathological examination of lung tissue showed severe histopathological lesions including thickened alveolar walls, narrowed alveolar cavity, and inflammatory cell infiltration in the MG-infected chicken group. However, PUE treatment significantly ameliorated MG-induced pathological damage in lung. Compared to the MG-infected group, PUE effectively inhibited the expression of MG-induced inflammatory genes, including tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), cytokines interleukin-6 (IL-6), toll-like receptor 6 (TLR6), myeloid differentiation primary response gene 88 (MyD88) and nuclear factor κB (NF-κB). Moreover, PUE dose-dependently inhibited MG-induced NF-κB p65 to enter the cell nucleus. In conclusion, our findings indicate that PUE treatment can efficiently inhibit MG-induced inflammatory response and apoptosis, and protect the lung from MG infection-induced damage by inhibiting the TLR6/MyD88/NF-κB signaling pathway activation. The study suggests that PUE may be a potential anti-inflammatory agent defense againstMGinfection in chicken.

Mycoplasma ovipneumoniae-derived lipid-associated membrane proteins induce cytokine secretion in mouse peritoneal macrophages through TLR2 signalling

BACKGROUND

Mycoplasma ovipneumoniae (M. ovi) is the causative agent of chronic non-progressive pneumonia in sheep, goats, bighorn, and wild small ruminants. However, the mechanism of infection and immune response to M. ovi remain unclear. Invading microbes express lipid-associated membrane proteins (LAMPs) on the cell surface that interact with host cells to facilitate infection, and are thus the major molecules recognised by the host immune system. Upon LAMP recognition, Toll-like receptor 2 (TLR2) and NLRP3 inflammasome sense the pathogens and signalling pathways for cytokine secretion. In this study, we investigated whether M. ovi and M. ovi-derived LAMPs are immuno-biologically active compounds capable of activating mouse peritoneal macrophages and explored the underlying mechanism.

RESULTS

After infection of wild-type mice with M. ovi, the expression of TLR2 and NLRP3 at the transcriptional and translational levels was determined with reverse transcription-polymerase chain reaction and flow cytometry. In addition, the cytokine levels and associated pathways were detected in infected wild-type, Tlr2^-/-, and Nlrp3^-/- mice via enzyme-linked immunosorbent assays and western blotting. The nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signalling pathways were found to mediate the expression of inflammatory cytokines in M. ovi or M. ovi-derived LAMP-infected peritoneal macrophages, and cytokines were not induced in Tlr2^-/- and/or Nlrp3^-/- macrophages.

CONCLUSION

Host cytokine production is activated in response to M. ovi-derived LAMPs through the NF-κB and MAPK signalling pathway via TLR2.

miR-143-3p impacts on pulmonary inflammatory factors and cell apoptosis in mice with mycoplasmal pneumonia by regulating TLR4/MyD88/NF-κB pathway

miR-143-3p is correlated with inflammatory pain responses, such as hsa-miR-143-3p expression reduction in fibromyalgia. The present study aimed to explore the effects of miR-143-3p and Toll-like receptor (TLR) 4/myeloid differentiation factor 88 (MyD88)/NF-κB signaling pathway on pulmonary inflammatory factors levels and alveolar epithelial cell apoptosis in mycoplasmal pneumonia mice. Twenty mice were selected as normal group. The 120 successfully modeled Mycoplasma pneumoniae (MP) infection mice were randomly divided into model group (without any treatment), negative control (NC) group (injected with NC mimic), miR-143-3p mimic group (injected with miR-143-3p mimic), miR-143-3p inhibitor group (injected with miR-143-3p inhibitor), TAK-242 group (treatment with TAK-242), and miR-143-3p inhibitor + TAK-242 group (treatment with miR-143-3p inhibitor + TAK-242). Compared with model group, model mice had up-regulated miR-143-3p expression and decreased MyD88 and p-NF-κB p50 protein expressions (all P<0.05); Model mice treated with miR-143-3p mimic and TAK-242 had reduced interleukin (IL)-2 and tumor necrosis factor (TNF)-α contents and protein expressions of MyD88, p-NF-κB p50, increased IL-10 content, fewer alveolar epithelial cell apoptosis, lower Bax expression and higher Bcl-2 expression (all P<0.05); however, mice with miR-143-3p inhibitor treatment showed opposite trends in terms of above indicators. The exacerbation of mycoplasmal pneumonia caused by miR-143-3p inhibitor was partly improved by miR-143-3p inhibitor + TAK-242 combination treatment (all P<0.05). Therefore, up-regulation of miR-143-3p expression may ameliorate pulmonary inflammatory factors levels and reduce alveolar epithelial cell apoptosis in mycoplasmal pneumonia mice by inhibiting TLR4/MyD88/NF-κB signaling pathway.

Multilocus sequence typing characterizes diversity of Ureaplasma diversum strains, and intra-species variability induces different immune response profiles

Background

Ureaplasma diversum is a pathogen found in the genital tract of cattle and associated with genital disorders such as infertility, placentitis, abortion, birth of weak calves, low sperm motility, seminal vesiculitis and epididymitis. There are few studies evaluating the genetic diversity of U. diversum strains and their influence on the immune response in cattle. Therefore, to better understand genetic relationships of the pathogenicity of U. diversum, a multilocus sequence typing (MLST) scheme was performed to characterize the ATCC 49782 strain and another 40 isolates recovered from different Brazilian states.

Results

Primers were designed for housekeeping genes ftsH, polC, rpL22, rpoB, valS and ureA and for virulence genes, phospholipase D (pld), triacylglycerol lipase (tgl), hemolysin (hlyA), MIB-MIP system (mib,mip), MBA (mba), VsA (VsA) and ribose transporter (tABC). PCRs were performed and the targeted gene products were purified and sequenced. Sequence types (STs), and clonal complexes (CCs) were assigned and the phylogenetic relationship was also evaluated. Thus, a total of 19 STs and 4 CCs were studied. Following the molecular analysis, six isolates of U. diversum were selected, inoculated into bovine monocyte/macrophage culture and evaluated for gene expression of the cytokines TNF-α, IL-1, IL-6, IL-10 and IL-17. Differences were detected in the induction of cytokines, especially between isolates 198 and BA78, promoted inflammatory and anti-inflammatory profiles, respectively, and they also differed in virulence factors.

Conclusion

It was observed that intra-species variability between isolates of U. diversum can induce variations of virulent determinants and, consequently, modulate the expression of the triggered immune response.

Baicalin Attenuates Mycoplasma gallisepticum-Induced Inflammation via Inhibition of the TLR2-NF-κB Pathway in Chicken and DF-1 Cells

Background

Previous reports demonstrated that baicalin possesses potential anti-inflammatory properties. The present study was conducted to determine the effects of baicalin against inflammatory responses in chicken and DF-1 cells infected with Mycoplasma gallisepticum (MG).

Methods

An MG infection model was developed in chickens to study the anti-inflammatory mechanism of baicalin. Baicalin was mixed in water at a dose of 450 mg/kg per day, and the treatment is continued for 7 consecutive days. Samples were taken at 1, 4, and 7 days post treatment.

Results

By using transmission electron microscopy, ultrastructure of lung and tracheal cells has been examined. It can be seen that the cilia cells in the MG-infected group have pyknosis, degeneration, and necrosis. In the lung tissues, alveolar type-I epithelial cells were severely damaged. In the baicalin-treated group, cilia were swollen, mushroom-shaped edema bubbles formed on the apex, and fused together. Alveolar type I epithelial cells injury was significantly reduced. Compared to MG-infection group, the levels of proinflammatory cytokines IL-1β and TNF-α were significantly decreased (P < 0.01). The corresponding proteins TLR2 and P-p65 decreased in the baicalin-treated group after 1 (p > 0.05), 4 (p < 0.05), and 7 days (p < 0.05), respectively.

Conclusion

The results showed that baicalin can interfere with inflammatory injury by suppressing the release of inflammatory cytokines IL-1β and TNF-α during MG infection both in vivo and in vitro. Meanwhile, baicalin suppressed TLR2-NFκB signaling pathway by inhibiting the phosphorylation of p65 and IκB, thereby affecting the expression of inflammatory factors. The results suggested that baicalin acts as a potential anti-inflammatory agent against MG infection in chicken and DF-1 cells.

Interleukin 1 alpha (IL-1α) restricts Brucella abortus 544 survival through promoting lysosomal-mediated killing and NO production in macrophages

The interleukin-1 (IL-1) family of cytokines, particularly IL-1α and IL-1β, are potent regulators of innate immunity that play key roles in host defense against infection, hence we evaluated the role of these cytokines in the control of brucellosis within RAW 264.7 cells. Marked expression and secretion of IL-1α and IL-1β were observed during Brucella infection in macrophages. Blocking of IL-1α and IL-1β reduced induction of IL-10, IL-1β and TNF, and IL-6 and TNF, respectively. However, interference of IL-1α and not IL-1β signaling notably augmented susceptibility of macrophages to Brucella infection which indicates that IL-1α is required for a downstream signaling cascade of innate immunity for efficient clearance of Brucella. This protection requires binding to interleukin-1 receptor (IL-1R) mediated by myeloid differentiation factor 88 (MyD88) signaling and associated with increased lysosomal-mediated killing and nitric oxide (NO) production. Expression of pro-inflammatory cytokines was observed to be mediated via NF-κB-p50, HIF-1α and CEBPA, but negatively controlled by CEBPB while transcription of some important phagolysosomal genes was regulated via CEBPA and c-Jun which indicates the important role of these transcription factors in the control of Brucella infection in macrophages via IL-1α signaling pathway.