Bacillus subtilis spores as adjuvants against avian influenza H9N2 induce antigen-specific antibody and T cell responses in White Leghorn chickens.

Low-pathogenicity avian influenza H9N2 remains an endemic disease worldwide despite continuous vaccination, indicating the need for an improved vaccine strategy. Bacillus subtilis (B. subtilis), a gram-positive and endospore-forming bacterium, is a non-pathogenic species that has been used in probiotic formulations for both animals and humans. The objective of the present study was to elucidate the effect of B. subtilis spores as adjuvants in chickens administered inactivated avian influenza virus H9N2. Herein, the adjuvanticity of B. subtilis spores in chickens was demonstrated by enhancement of H9N2 virus-specific IgG responses. B. subtilis spores enhanced the proportion of B cells and the innate cell population in splenocytes from chickens administered both inactivated H9N2 and B. subtilis spores (Spore + H9N2). Furthermore, the H9N2 and spore administration induced significantly increased expression of the pro-inflammatory cytokines IL-1ß and IL-6 compared to that in the H9N2 only group. Additionally, total splenocytes from chickens immunized with inactivated H9N2 in the presence or absence of B. subtilis spores were re-stimulated with inactivated H9N2. The subsequent results showed that the extent of antigen-specific CD4+ and CD8+ T cell proliferation was higher in the Spore + H9N2 group than in the group administered only H9N2. Taken together, these data demonstrate that B. subtilis spores, as adjuvants, enhance not only H9N2 virus-specific IgG but also CD4+ and CD8+ T cell responses, with an increase in pro-inflammatory cytokine production. This approach to vaccination with inactivated H9N2 together with a B. subtilis spore adjuvant in chickens produces a significant effect on antigen-specific antibody and T cell responses against avian influenza virus.

Dudleya brittonii extract promotes survival rate and M2-like metabolic change in porcine 3D4/31 alveolar macrophages.

OBJECTIVE: Although alveolar macrophages play a key role in the respiratory immunity of livestock, but studies on the mechanism of differentiation and survival of alveolar macrophages are lacking. Therefore, we undertook to investigate changes in the lipid metabolism and survival rate, using 3D4/31 macrophages and Dudleya brittonii which has been used as a traditional asthma treatment. METHODS: 3D4/31 macrophages were used as the in vitro porcine alveolar macrophages model. The cells were activated by exposure to Phorbol 12-Myristate 13-Acetate (PMA). D. Brittonii extraction was performed with distilled water. For evaluating the cell survival rate, we performed the water-soluble tetrazolium salt (WST) cell viability assay and growth curve analysis. To confirm cell death, cell cycle and intracellular reactive oxygen species levels were measured using flow cytometric analysis by applying fluorescence dye dichlorofluorescein diacetate (DCFDA) and propidium iodide (PI). Furthermore, we also evaluated cellular lipid accumulation with Oil Red O staining, and fatty acid synthesis related genes expression levels using quantitative PCR (qPCR) with SYBR green dye. Glycolysis, fatty acid oxidation, and tricarboxylic acid (TCA) cycle related gene expression levels were measured using qPCR after exposure to Dudleya brittonii extract (DB) for 12 h. RESULTS: Reactive oxygen species (ROS) production and cell death were induced by PMA treatment, and exposure to DB reduced the PMA induced downregulation of cell survival. PMA and DB treatments upregulated the lipid accumulation, with corresponding increase in the acetyl-CoA carboxylase alpha (ACACA), fatty acid synthase (FASN) mRNA expressions. DB-PMA co-treatment reduced the glycolysis genes expression, but increased the expressions of fatty acid oxidation and TCA cycle genes. CONCLUSION: This study provides new insights and directions for further researches relating to the immunity of porcine respiratory system, by employing a model based on alveolar macrophages and natural materials.

Antiproliferative Effect of Vine Stem Extract from Spatholobus Suberectus Dunn on Rat C6 Glioma Cells Through Regulation of ROS, Mitochondrial Depolarization, and P21 Protein Expression.

The vine stem of Spatholobus suberectus Dunn (SS) is used as a traditional herbal medicine in China. Chinese herbal medicines are well known as natural bioactive compounds that can be used as new medicines, and their antioxidant and anticancer effects have also been reported. This study aimed to examine the anticancer effect of a high-pressure hot-water SS extract on rat C6 glioma cells. The SS extract effectively suppressed the viability and proliferation of C6 glioma cells through an antioxidant effect. Reactive oxygen species (ROS) levels in cancer cells are higher than that in normal cells. If the ROS level falls below that required for the growth of cancer cells, their rapid proliferation and growth can be suppressed. We also measured the induction of mitochondrial membrane depolarization and cell cycle arrest effect caused by the SS extract in C6 glioma cells through a FACS analysis. In addition, we observed an increase in STAT3, p53, E2F1, and p21 mRNA expression and a decrease in Bcl-2 mRNA expression by quantitative PCR. An increase in p21 protein expression of over 83% was observed through western blot analysis. All these data support the fact that the high-pressure hot-water SS extract has the potential to be used for glioma treatment.

Novel potential NOX2 inhibitors, Dudleya brittonii water extract and polygalatenoside A inhibit intracellular ROS generation and growth of melanoma.

Reactive oxygen species (ROS) are key regulators of the proliferation, metastasis, and drug resistance of melanoma, which accounts for 60% of skin cancer deaths. In a previous study, we developed Dudleya brittonii water extract (DBWE) with antioxidant activity, but the mechanism of action and bioactive substances of DBWE have not been fully identified. This study showed altered NADPH oxidase 2 (NOX2) expression and selective inhibition of cytosolic ROS but not mitochondrial ROS in B16-F10 melanoma cells, suggesting the NOX2 inhibitory potential of DBWE. In addition, DBWE inhibited mitochondrial activity, lipid metabolism, and cell cycle in B16-F10 cells. The anti-melanoma effect of DBWE was abrogated by the addition of ROS, and there was no significant change in the melanogenesis pathway. Polygalatenoside A was identified as a candidate bioactive substance in the DBWE aqueous fraction through mass spectrometry, and the DBWE-like anti-melanoma effect was confirmed. These data suggest that DBWE and polygalatenoside A have the potential to prevent and treat melanoma.

Suppression of the Toll-like receptors 3 mediated pro-inflammatory gene expressions by progenitor cell differentiation and proliferation factor in chicken DF-1 cells.

Toll-like receptors (TLRs), as a part of innate immunity, plays an important role in detecting pathogenic molecular patterns (PAMPs) which are structural components or product of pathogens and initiate host defense systems or innate immunity. Precise negative feedback regulations of TLR signaling are important in maintaining homeostasis to prevent tissue damage by uncontrolled inflammation during innate immune responses. In this study, we identified and characterized the function of the pancreatic progenitor cell differentiation and proliferation factor (PPDPF) as a negative regulator for TLR signal-mediated inflammation in chicken. Bioinformatics analysis showed that the structure of chicken PPDPF evolutionarily conserved amino acid sequences with domains, i.e., SH3 binding sites and CDC-like kinase 2 (CLK2) binding sites, suggesting that relevant signaling pathways might contribute to suppression of inflammation. Our results showed that stimulation with polyinosinic:polycytidylic acids (Poly [I:C]), a synthetic agonist for TLR3 signaling, increased the mRNA expression of PPDPF in chicken fibroblasts DF-1 but not in chicken macrophage-like cells HD11. In addition, the expression of pro-inflammatory genes stimulated by Poly(I:C) were reduced in DF-1 cells which overexpress PPDPF. Future studies warrant to reveal the molecular mechanisms responsible for the anti-inflammatory capacity of PPDPF in chicken as well as a potential target for controlling viral resistance.