Guizhou Yue

The enhancement of immune function and activation of NF-κB by resveratrol-treatment in immunosuppressive mice.

Resveratrol, a kind of natural product found in over 70 plants, possesses both immunomodulatory and anticancer effects. Many reports have shown that resveratrol has the bidirectional regulation effects on antigen presenting and cellular immunity. However, few reports have evaluated the effects of resveratrol on reinforcing immunity recovery via activating nuclear factor -κappa B (NF-κB). In the present study, we investigated the effects of resveratrol on recovery and reconstruction of immune function by detecting nonspecific and specific immunity in immunosuppressive mice. We found that, compared to the immunosuppressive mice, the spleen index and spleen lymphocyte proliferation of resveratrol-treated mice (30 mg/kg body weight) were enhanced. After resveratrol-treatment (15 mg/kg body weight), the function of peritoneal macrophages was enhanced and the CD4+ cells were increased in peripheral blood. The expressions of serum cytokines related to immune function, including interleukin (IL)-1α/β, IL-2, tumor necrosis factor-α and NF-κB were up-regulated in a dose-dependent manner. The expression of the transcription factor NF-κB in spleen was enhanced after resveratrol-treatment. The immuno-enhancement effects of resveratrol were similar to that of levamisole (served as positive control). These results demonstrated that resveratrol had potent immune enhancement activity in immunosuppressive mice, and one possible mechanism of action was to activate the NF-κB.

The antibacterial activity and action mechanism of emodin from Polygonum cuspidatum against Haemophilus parasuis in vitro

Haemophilus parasuis is the causative agent of Glässers disease, which leads to serious economic loss to the swine industry. Although antibiotics are widely used to control infections, outbreaks of this disease repeatedly happen. In this study, emodin from Polygonum cuspidatum showed potent inhibitory effect against H. parasuis. The minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values of emodin were 32 and 64μg/mL, respectively. The antibacterial kinetic curves indicated the antibacterial activity of emodin was in a concentration-dependent manner. Cell membrane permeability and flow cytometry assays proved that emodin could destroy cell membrane integrity and increase membrane permeability, and fluorescence spectra assay indicated emodin has influenced conformation of membrane protein. Under transmission electron microscopy, serious lesions of H. parasuis exposed to emodin (64μg/mL) were found, including irregular cell shape, plasmolysis, ruptured cell wall and membrane and cytoplasmic vacuolation. These results suggested that emodin could be used as candidate for treating Glässers disease.

Antiviral effect of resveratrol in ducklings infected with virulent duck enteritis virus.

Duck enteritis virus (DEV) is a double-stranded DNA virus belonging to the alphaherpesvirinae subfamily of the herpesviridae. Although vaccines were wildly used in controlling this disease, some infection could still not be prevented and led to significant economic losses as a result of mortality and decreased egg production. However, there is no antiviral drug against DEV. Resveratrol was identified to exert its antiviral activity by inhibiting the DEV replication in preliminary investigations. In the present study, we confirmed that resveratrol significantly reduced the mortality of ducklings which infected with a virulent strain of DEV. With resveratrol treatment, the survival rate increased by almost 80% at 8 days post infection (dpi). Pathological symptoms of ducklings caused by DEV were also relieved by resveratrol. The virus load in blood and tissues were effectively depressed when compared with the untreated group. In the assay of immune cytokines, the resveratrol exerted a dual-regulation effect. These results suggest that resveratrol is expected to be a new alternative control measure for DEV infection.

Resveratrol promotes recovery of immune function of immunosuppressive mice by activating JNK/NF-κB pathway in splenic lymphocytes

Resveratrol, a natural compound found in over 70 plants, is known to possess immunoregulatory effects and anti-inflammatory activity. It has been shown that resveratrol has regulatory effects on different signaling pathways in different diseases. However, few reports have evaluated the effects of resveratrol on reinforcing immunity recovery via activating nuclear factor-κB (NF-κB) pathway and Jun N-terminal kinases (JNK) pathway. The present study aimed to assess immune-enhancing activity and underlying mechanism of resveratrol in immunosuppressive mice. Previously, we reported that resveratrol could promote mouse spleen lymphocyte functions to recover the immune system effectively. In the present study, we show that resveratrol could upregulate the expressions of NF-κB, IκB kinase, JNK, and c-jun in splenic lymphocytes of immunosuppressive mice. Taken together, our results indicate that resveratrol could promote recovery of immunologic function in immunosuppressive mice by activating JNK/NF-κB pathway.

Transcriptomics and proteomic studies reveal acaricidal mechanism of octadecanoic acid-3, 4 - tetrahydrofuran diester against Sarcoptes scabiei var. cuniculi

In our previous study, a new compound, octadecanoic acid-3, 4-tetrahydrofuran diester, possessing potent acaricidal activity was obtained from neem oil. This study performed RNA-seq transcriptomics and iTRAQ proteomics to uncover the acaricidal mechanism of the compound against Sarcoptes scabiei var. cuniculi. The results of transcriptomics indicated that after treatment with octadecanoic acid-3, 4-tetrahydrofuran diester, genes related to “Energy metabolism” were significantly up-/down-regulated, including citrate cycle, oxidative phosphorylation pathway and fatty acid metabolism. Proteomics analysis showed accordant changes of proteins related to oxidative phosphorylation pathway. The target proteins of the compound were NADH dehydrogenase, Ubiquinol-cytochrome c reductase, Cytochrome c oxidase, ATP synthase, enolase and superoxide dismutase. In transcriptomics-proteomics correlation analysis, the concordance rate between protein abundances and their corresponding mRNAs was 57%, while others (43%) were discordant changes, suggesting divergent regulating effects of octadecanoic acid-3, 4-tetrahydrofuran diester. These results suggested that the acaricidal mechanism of octadecanoic acid-3, 4-tetrahydrofuran diester attributed to interference with energy metabolism, especially oxidative phosphorylation pathway.

Antiviral Effect of Resveratrol in Piglets Infected with Virulent Pseudorabies Virus

Pseudorabies virus (PRV) is one of the most important pathogens of swine, resulting in devastating disease and economic losses worldwide. Nevertheless, there are currently no antiviral drugs available for PRV infection. Resveratrol (Res) was identified to exert its antiviral activity by inhibiting the PRV replication in preliminary investigations. In our previous study, we found that Res has anti-PRV activity in vitro. Here, we show that Res can effectively reduce the mortality and increase the growth performance of PRV-infected piglets. After Res treatment, the viral loads significantly (p < 0.001) decreased. Pathological symptoms, particularly inflammation in the brain caused by PRV infection, were significantly (p < 0.001) relieved by the effects of Res. In Res-treated groups, higher levels of cytokines in serum, including interferon gama, interleukin 12, tumor necrosis factor-alpha and interferon alpha were observed at 7 days post infection. These results indicated that Res possesses potent inhibitory activity against PRV-infection through inhibiting viral reproduction, alleviating PRV-induced inflammation and enhancing animal immunity, suggesting that Res is expected to be a new alternative control measure for PRV infection.

Two complement fixing pectic polysaccharides from pedicel of Lycium barbarum L. promote cellular antioxidant defense

Purification, characterization and biological activities of polysaccharides from Lycium barbarum pedicel were investigated in this study. Two polysaccharides, PLBP-I-I and PLBP-II-I, were obtained from water extracts by anion exchange chromatography and gel filtration. Structural elucidation based on IR, 1H NMR, and 13C NMR spectra indicated that these two fractions were typical pectic polysaccharides, with homogalacturonan and rhamnogalacturonan type I regions and arabinogalactan side chains, and some of the galacturonic acid units were methyl esterified. Both fractions exhibited potent complement fixating activity and pro-antioxidant defense capacity, and those two fractions showed different activities. The higher complement fixation activity was obtained in fraction PLBP-I-I, while the higher pro-antioxidant defense capacity was obtained in fraction PLBP-II-I, which may be due to the structural differences between those two fractions. Thus, the pedicel of L. barbarum could be used as a potential source for natural immunomodulator and antioxidant.

Effect of Resveratrol Dry Suspension on Immune Function of Piglets

Resveratrol, a polyphenolic plant antitoxin, has a wide range of pharmacological activities. In this study, we systematically evaluated the effects of resveratrol dry suspension (RDS) on immune function in piglets that were treated with different doses of RDS for 2 weeks. The results showed that the RDS has significant effects on the development, maturation, proliferation, and transformation of T lymphocytes. RDS could regulate humoral immune responses by upregulating the release of IFN-γ and downregulating the release of TNF-α. After piglets were vaccinated against classical swine fever virus and foot-and-mouth disease virus, the antibody titers were significantly increased. RDS treatment showed an excellent resistance to enhance T-SOD activity. Values of blood routine and blood biochemistry showed no toxicity. These results suggested that RDS could be considered as an adjuvant to enhance immune responses to vaccines, as well as dietary additives for animals to enhance humoral and cellular immunity.

iTRAQ-based quantitative proteomic analysis reveals multiple effects of Emodin to Haemophilus parasuis

Haemophilus parasuis, a symbiotic bacteria of upper respiratory tract of swine, is the etiological agent of Glässers disease, which is characterized by fibrinous polyserositis. Emodin, exhibits antibacterial activity against H. parasuis, yet the action mode has not been fully understood. In present study, isobaric tag for relative and absolute quantification (iTRAQ) method was applied to analyze the global protein alteration of H. parasuis in response to 16μg/mL Emodin. In total, 338 proteins exhibiting significant differential expressions were identified. It was speculated that, through application of bioinformatics analysis to theses differentially expressed proteins, Emodin mainly inhibited some key proteins expression of ABC transport system, carbohydrate metabolism pathway and bacterial cell division by inhibiting the ribosome synthesis, resulting in the growth inhibition of H. parasuis. Remarkably, nine virulence-associated proteins were detected differently expressed, further experiments revealed that after treatment with Emodin, H. parasuis could be inhibited to adhere to and invade into porcine kidney epithelial cells (PK-15 line) and exhibited increased sensitivity to serum complement in a concentration-dependent manner. Phagocytosis assay showed Emodin also could enhance phagocytic activity of porcine alveolar macrophages PAM to H. parasuis. These results indicated that Emodin also can attenuate virulence of H. parasuis and reduce infection. BIOLOGICAL SIGNIFICANCE The Glässers disease caused by H. parasuis has become a typical bacterial disease and cause serious economic loss to the swine industry around the world. Antibiotics are extensively used to control the infection, but increasing antibiotic resistance has been a severe problem. Hence, novel treatment agents are needed. So far, few antibacterial agents were reported that could control H. parasuis infection. In the present study, the state-of-the-art quantitative proteomic technology was applied to uncover underlying action mechanism of Emodin. This study extends understanding of antibacterial effect of Emodin to H. parasuis at molecular level and provides useful information for further investigations. Moreover, our results provide theoretical foundation for the practical application of Emodin.

Astragaloside IV inhibits PMA-induced EPCR shedding through MAPKs and PKC pathway

Abstract Astragaloside IV (AS-IV), a main active substance isolated from Astragalus membranaceus Bunge, has been shown to have multiple pharmacological effects. Endothelial cell protein C receptor (EPCR) is a marker of inflammation, and is also a major member of protein C (PC) anti-coagulation system. EPCR can be cut off from the cell surface by tumor necrosis factor-α converting enzyme (TACE), which is controlled through mitogen-activated protein kinase (MAPK) and protein kinase C (PKC) pathways. To develop novel therapeutic drug for EPCR shedding, the effect of AS-IV was studied in phorbol-12-myristate 13-acetate (PMA)-induced human umbilical vein endothelial cells (HUVECs) and the potential molecular mechanism of AS-IV action was investigated. The results showed that AS-IV could significantly inhibit PMA-induced EPCR shedding. In further study, AS-IV suppressed the expression and activity of TACE. In addition, AS-IV could decrease the phosphorylation of MAPK such as janus kinase (JNK) and p38, and inhibit activation of PKC through the prevention of non-phosphorylation and phosphorylation of specific PKC isoforms in PMA-stimulated HUVECs. These findings indicate that AS-IV may be used as a natural medicine to treat EPCR-related systemic inflammation and cardiovascular diseases by targeting MAPK and PKC pathway.