Inhibitory effect of polysaccharide of Sargassum weizhouense on PCV2 induced inflammation in mice by suppressing histone acetylation

Agrocybe cylindracea fucoglucogalactan induced lysosome-mediated apoptosis of colorectal cancer cell through H3K27ac-regulated cathepsin D

Inducing lysosomal dysfunction is emerging as a promising means for cancer therapy. Agrocybe cylindracea fucoglucogalactan (ACP) is a bioactive ingredient with anti-tumor activity, while its mechanism remains obscure. Herein, we found that ACP visibly inhibited the proliferation of colorectal cancer cells, and the IC50 value on HCT-116 cells (HT29 cells) was 490 μg/mL (786.4 μg/mL) at 24 h. RNA-seq showed that ACP regulated mitochondria, lysosome and apoptosis-related pathways. Further experiments proved that ACP indeed promoted apoptosis and lysosomal dysfunction of HCT-116 cells. Moreover, ChIP-seq revealed that ACP increased histone-H3-lysine-27 acetylation (H3K27ac) on CTSD (cathepsin D) promoter in HCT-116 cells, thus facilitating the binding of transcription factor EB (TFEB), and resulted in ascension of CTSD expression. Additionally, ACP triggered mitochondrial-mediated apoptosis by decreasing mitochondrial membrane potential and increasing pro-apoptotic protein levels. Notably, Pepstatin A (CTSD inhibitor) availably alleviated ACP-induced apoptosis. Taken together, our results indicated that ACP induced lysosome-mitochondria mediated apoptosis via H3K27ac-regulated CTSD in HCT-116 cells. This study indicates that ACP has anti-cancer potential in the treatment of colorectal cancer.

Relevance of the Extraction Stage on the Anti-Inflammatory Action of Fucoidans

The anti-inflammatory action of fucoidans is well known, based on both in vitro and some in vivo studies. The other biological properties of these compounds, their lack of toxicity, and the possibility of obtaining them from a widely distributed and renewable source, makes them attractive novel bioactives. However, fucoidans’ heterogeneity and variability in composition, structure, and properties depending on seaweed species, biotic and abiotic factors and processing conditions, especially during extraction and purification stages, make it difficult for standardization. A review of the available technologies, including those based on intensification strategies, and their influence on fucoidan composition, structure, and anti-inflammatory potential of crude extracts and fractions is presented.

Intervening Effects and Molecular Mechanism of Quercitrin on PCV2-Induced Histone Acetylation, Oxidative Stress and Inflammatory Response in 3D4/2 Cells

Porcine circovirus type 2 (PCV2) is the main pathogen causing porcine circovirus-associated diseases (PCVD/PCVADs), and infection of the host induces immunosuppression. Since quercitrin (QUE) has anti-inflammatory and antiviral activity, it is worth exploiting in animal diseases. In this study, the interventional effects and the molecular mechanism of QUE on PCV2-induced oxidative stress and inflammatory responses in 3D4/2 cells and the modulation of histone acetylation modifications were investigated. The ROS production was measured by DCFH-DA fluorescent probes. HAT and HDAC enzyme activity were determined by ELISA. Histone acetylation, oxidative stress and inflammation-related gene expression levels were measured by q-PCR. Histone H3 and H4 (AcH3 and AcH4) acetylation, oxidative stress and inflammation-related protein expression levels were measured by Western blot. The results showed that QUE treatment at different concentrations on PCV2-infected 3D4/2 cells was able to attenuate the production of ROS. Moreover, QUE treatment could also intervene in oxidative stress and decrease the enzyme activity of HAT and the mRNA expression level of HAT1, while it increased the enzyme activity of HDAC and HDAC1 mRNA expression levels and downregulated histone H3 and H4 (AcH3 and AcH4) acetylation modification levels. In addition, QUE treatment even downregulated the mRNA expression levels of IL-6, IL-8, IκB, AKT and p38, but upregulated the mRNA expression levels of IL-10, SOD, GPx1, p65, Keap1, Nrf2, HO-1 and NQO1. As to protein expression, QUE treatment downregulated the levels of iNOS, p-p65 and IL-8 as well as the phosphorylation expression of IκB and p38, while it upregulated the levels of HO-1 and NQO1. It was shown that QUE at 25, 50 or 100 μmol/L regulated p38MAPK and PI3K/AKT signaling pathways by downregulating cellular histone acetylation modification levels while inhibiting the NF-κB inflammatory signaling pathway and activating the Nrf2/HO-1 antioxidant signaling pathway, thus regulating the production of inflammatory and antioxidant factors and exerting both anti-inflammatory and antioxidant effects.

PCV2 infection aggravates OTA-induced immunotoxicity in vivo and in vitro

Ochratoxin A (OTA), frequently existing in the food and feeds, could induce immunotoxicity. Porcine circovirus type 2 (PCV2), as a primary causative agent of porcine circovirus-associated disease, also could induce immunosuppression. However, it is still unknown whether PCV2 infection impacts OTA-induced immunotoxicity. The pigs and porcine alveolar macrophages (PAMs) were used as the model in the present experiment. The results in vivo indicated that PCV2 infection exacerbated OTA-induced immunotoxicity, NF-κB p65 phosphorylation, and TLR4 and MyD88 mRNA and protein expression in spleen. The results in vitro showed that OTA at 7.0 and 9.0 μM decreased cell viability and increased LDH release of PAMs without PCV2 infection. However, with PCV2 infection, OTA at 5.0, 7.0 and 9.0 μM significantly decreased cell viability and increased LDH release compared with absence of PCV2 infection. In addition, OTA at 5.0 and 7.0 μM significantly increased Annexin V/PI-positive rate, apoptosis of nuclear, γ-H2AX foci, IL-1α and TNF-α expression in PAMs with PCV2 infection compared with absence of PCV2 infection. In addition, PCV2 infection enhanced OTA-induced TLR4 and MyD88 mRNA and protein expression and NF-κB p65 phosphorylation. Knockdown of TLR4 alleviated the exacerbating effects of PCV2 infection on OTA-induced cytotoxicity, apoptosis and DNA damage in PAMs. These results indicated that PCV2 infection aggravated OTA-induced immunotoxicity and reduced the dose of OTA-induced immunotoxicity via TLR4/NF-κB p65 signaling pathway, which could provide basis for establishing limits for OTA.

Anti-Inflammatory Mechanisms of Fucoidans to Treat Inflammatory Diseases: A Review

Fucoidans are sulfated heteropolysaccharides found in the cell walls of brown seaweeds (Phaeophyceae) and in some marine invertebrates. Generally, fucoidans are composed of significant amounts of L-fucose and sulfate groups, and lesser amounts of arabinose, galactose, glucose, glucuronic acid, mannose, rhamnose, and xylose. In recent years, fucoidans isolated from brown seaweeds have gained considerable attention owing to their promising bioactive properties such as antioxidant, immunomodulatory, anti-inflammatory, antiobesity, antidiabetic, and anticancer properties. Inflammation is a complex immune response that protects the organs from infection and tissue injury. While controlled inflammatory responses are beneficial to the host, leading to the removal of immunostimulants from the host tissues and restoration of structural and physiological functions in the host tissues, chronic inflammatory responses are often associated with the pathogenesis of tumor development, arthritis, cardiovascular diseases, diabetes, obesity, and neurodegenerative diseases. In this review, the authors mainly discuss the studies since 2016 that have reported anti-inflammatory properties of fucoidans isolated from various brown seaweeds, and their potential as a novel functional material for the treatment of inflammatory diseases.

Dietary polysaccharides exert biological functions via epigenetic regulations: Advance and prospectives

Bioactive substances derived from natural products are valued for effective health-related activities. As extremely important component of plants, animal cell membrane and microbes cytoderm, polysaccharides have been applied as medications, foods and cosmetics stemming from their prominent biological functions and minor side-effects. Recent studies indicate that polysaccharides exert biological effects also through epigenetic mechanism. Through the intervention of DNA methylation, histone modification, and non-coding RNA, polysaccharides participatate in regulation of immunity/inflammation, glucose and lipid metabolism, antioxidant damage and anti-tumor, which presents novel mechanism of polysaccharide exerting various functions. In this review, the latest advances in the biological functions of dietary polysaccharides via epigenetic regulations were comprehensively summarized and discussed. From the view point of epigenetic regulation, investigating the relationship between polysaccharides and biological effects will enhance our understandings of polysaccharides and also means huge breakthrough of molecular mechanism in the polysaccharide research fields. The paper will provide important reference to these investigators of polysaccharide research and expand the applications of dietary polysaccharides in the functional food developments.

Combined Effect of Deoxynivalenol (DON) and Porcine Circovirus Type 2 (Pcv2) on Inflammatory Cytokine mRNA Expression

A host’s immune system can be invaded by mycotoxin deoxynivalenol (DON) poisoning and porcine circovirus type 2 (PCV2) infections, which affect the host’s natural immune function. Pro-inflammatory cytokines, IL-1β and IL-6, are important regulators in the process of natural immune response, which participate in inflammatory response and enhance immune-mediated tissue damage. Preliminary studies have shown that DON promotes PCV2 infection by activating the MAPK signaling pathway. Here, we explored whether the mRNA expression of IL-1β and IL-6, induced by the combination of DON and PCV2, would depend on the MAPK signaling pathway. Specific pharmacological antagonists U0126, SP600125 and SB203580, were used to inhibit the activities of ERK, JNK and p38 in the MAPK signaling pathway, respectively. Then, the mRNA expression of IL-1β and IL-6 in PK-15 cells was detected to explore the effect of the MAPK signaling pathway on IL-1β and IL-6 mRNA induced by DON and PCV2. The results showed that PK-15 cells treated with DON or PCV2 induced the mRNA expression of IL-1β and IL-6 in a time- and dose-dependent manner. The combination of DON and PCV2 has an additive effect on inducing the mRNA expression of IL-1β and IL-6. Additionally, both DON and PCV2 could induce the mRNA expression of IL-1β and IL-6 via the ERK and the p38 MAPK signal pathways, while PCV2 could induce it via the JNK signal pathway. Taken together, our results suggest that MAPKs play a contributory role in IL-1β and IL-6 mRNA expression when induced by both DON and PCV2.

Effects of astragalus polysaccharide on intestinal inflammatory damage in goslings infected with gosling plague

1. This study explored the effects of Astragalus membranaceus polysaccharide (APS) on intestinal inflammatory damage of goslings infected with parvovirus ('gosling plague').2. A total of 90 healthy goslings were randomly divided into three groups; control, infected or APS treated, respectively. Goslings in the infection and APS treatment groups were inoculated with 0.3 ml allantoic fluid containing goose parvovirus (ELD₅₀ = 1 × 10³/0.3 ml) by intramuscular injection and the control group were injected with saline (0.3 ml) twice a day for 15 days.3. Blood serum and the jejunum were collected at 5, 10 and 15 days after the start of the experiment to detect the activities of SOD and GSH-Px, levels of MDA, sIgA, IL-1β, IL-6 and TNF-α, the mRNA expression of IL-1β, IL-6, LITAF, NF-κB, COX-2 and PGE2, pathological damage in the jejunum and serum IgG, IgM, C3, C4, IFN-γ levels.4. After APS treatment, SOD and GSH-Px activities increased, MDA content decreased; sIgA, IL-1β, IL-6 and TNF-α protein content, and IL-1β, IL-6, LITAF, NF-κB, COX-2 and PGE2 mRNA expression decreased in the jejunal tissue, serum IgG, IgM, C3, C4, IFN-γ significantly increased and pathological damage of jejunum significantly improved.5. In conclusion, APS reduced intestinal inflammatory damage in goslings infected with parvovirus by improving the immune and antioxidant functions of goslings.