Effects of Se-enriched polysaccharides produced by Enterobacter cloacae Z0206 on alloxan-induced diabetic mice

Ebosin Attenuates the Inflammatory Responses Induced by TNF-α through Inhibiting NF-κB and MAPK Pathways in Rat Fibroblast-Like Synoviocytes

Tumor necrosis factor-α (TNF-α) lies at the apex of signal transduction cascades that results in induced destruction of joints in rheumatoid arthritis. It is therefore of great medicinal interest to modulate the cellular responses to TNF-α. Ebosin, a novel exopolysaccharide derived from Streptomyces sp, has been demonstrated to have remarkable therapeutic actions on collagen-induced arthritis in rats, while it also suppressed the production of IL-1β, TNF-α, and IL-6 at both mRNA and protein levels in cultured fibroblast-like synoviocytes. In order to further understand the potential mechanisms involved in the anti-inflammatory effects of ebosin at molecular level, we investigated the impact of it on the activation of MAPK and NF-κB pathways following TNF-α induced in fibroblast-like synoviocytes (FLS). The results showed that the phosphorylation levels of TNF-α-induced p38, JNK1, JNK2, IKKα, IKKβ, and IκB, as well as NF-κB nuclear translocation, were reduced significantly in FLS cells in response to ebosin. Furthermore, we proved that ebosin decreased the level of NF-κB in the nucleus and blocked the DNA-binding ability of NF-κB using electrophoresis mobility gel shift assay. Besides, low levels of matrix metalloproteinases (MMP-1 and MMP-3) and chemokines (interleukin-8 and RANTES) were found in TNF-α-stimulated fibroblast-like synoviocytes treated with ebosin. These results indicate that ebosin can suppress a range of activities in both MAPK and NF-κB pathways induced by TNF-α in rat fibroblast-like synoviocytes, which provides a rationale for examining the use of ebosin as a potential therapeutic candidate for rheumatic arthritis.

Role of Postbiotics in Diabetes Mellitus: Current Knowledge and Future Perspectives

In the last decade, the gastrointestinal microbiota has been recognised as being essential for health. Indeed, several publications have documented the suitability of probiotics, prebiotics, and symbiotics in the management of different diseases such as diabetes mellitus (DM). Advances in laboratory techniques have allowed the identification and characterisation of new biologically active molecules, referred to as “postbiotics”. Postbiotics are defined as functional bioactive compounds obtained from food-grade microorganisms that confer health benefits when administered in adequate amounts. They include cell structures, secreted molecules or metabolic by-products, and inanimate microorganisms. This heterogeneous group of molecules presents a broad range of mechanisms and may exhibit some advantages over traditional “biotics” such as probiotics and prebiotics. Owing to the growing incidence of DM worldwide and the implications of the microbiota in the disease progression, postbiotics appear to be good candidates as novel therapeutic targets. In the present review, we summarise the current knowledge about postbiotic compounds and their potential application in diabetes management. Additionally, we envision future perspectives on this topic. In summary, the results indicate that postbiotics hold promise as a potential novel therapeutic strategy for DM.

Structural characterization and antitumor activity of a novel Se-polysaccharide from selenium-enriched Cordyceps gunnii

Selenium (Se) has been recognized as an essential element.

Biosynthesis of selenium rich exopolysaccharide (Se-EPS) by Pseudomonas PT-8 and characterization of its antioxidant activities

Biosynthesis of organo-selenium is achieved by submerged fermentation of selenium-tolerant Pseudomonas PT-8. The end product of metabolic process is selenium-bearing exopolysaccharide (Se-EPS), which contains a higher content of uronic acid than the exopolysaccharide (EPS) by the strain without selenium in the culture medium. Selenium content in Se-EPS reached a maximum yield of 256.7 mg/kg when using an optimized culture condition. Crude Se-EPS was purified into two fractions-a pH neutral Se-EPS-1 and an acidic Se-EPS-2. Structure and chemical composition of Se-EPS-2 were investigated by chromatographic analyses. Results showed that Se-EPS-2 was a homogenous polysaccharide with molecular weight of 7.3 kDa, consisting of monosaccharides, rhamnose, arabinose, xylose, mannose, glucose and galactose with a molar ratio of 19.58:19.28:5.97:18.99:23.70:12.48, respectively. Compared to the EPS, the content of rhamnose in Se-EPS increased and molecular weight decreased. The Se-EPS had strong scavenging actions on DPPH•, •OH and •O2(-), which is much higher than the EPS.

Effect of ebosin on modulating interleukin-1β-induced inflammatory responses in rat fibroblast-like synoviocytes

The interleukin-1β-mitogen-activated protein kinase (MAPK) and NF-κB signaling pathways are involved in the pathogenesis of rheumatoid arthritis. Ebosin, a novel exopolysaccharide (EPS), exhibits anti-inflammatory activity in rat collagen-induced arthritis by suppressing the production of tumor necrosis factor-α, interleukin-6 and interleukin-1β. The aim of the present study was to assess the effects of ebosin on NF-κB and MAPK signaling pathways mediated through interleukin-1β in rat fibroblast-like synoviocytes (FLSs). Western blotting showed decreased production of phosphorylated p38, JNK1, JNK2, IKKα, IKKβ and IκB in the cytoplasm and NF-κB in the nucleus upon ebosin treatment. The DNA-binding activity of NF-κB in the cell nucleus was also inhibited by ebosin treatment, as demonstrated using an electrophoresis mobility gel shift assay. Analysis of the results of the immunofluorescence assay also showed a reduced amount of NF-κB in the nucleus of cells affected by ebosin. These results provided evidence for the effects of ebosin on both interleukin-1β-mediated MAPK and NF-κB signaling pathways in rat FLSs. In addition, enzyme-linked immunosorbent assay demonstrated that ebosin reduces the levels of matrix metalloproteinases MMP-1 and MMP-3 and the chemokines, interleukin-8 and RANTES. Thus, the results of the present study provide further evidence for understanding the medicinal activity of ebosin at a molecular level, therefore nominating this EPS as a potential therapeutic candidate for the treatment of rheumatic arthritis.Cellular & Molecular Immunology advance online publication, 4 May 2015; doi:10.1038/cmi.2015.36.

Extraction, characterization and antioxidant activities of Se-enriched tea polysaccharides

Se-polysaccharides from Se-enriched tea leaves were purified by DEAE-sepharose fast flow gel column (2.5×60cm) and three polysaccharide fractions (Se-TPS1, Se-TPS2, and Se-TPS3) were isolated and purified with yields of 6.5, 37.14, and 8.57%, respectively. The average sizes of Se-TPS1 and Se-TPS2 were determined by HPGPC system, with molecular weights of 1.1×10(5) and 2.4×10(5)Da, respectively. Se-TPS3 was a polysaccharide polymer with two peaks with molecular weights of 9.2×10(5) and 2.5×10(5)Da. Monosaccharide components analysis by ion chromatography revealed Se-polysaccharides were acidic polysaccharoses and different from each other in monosaccharide kinds and molar ratio. Elements of Se, C, H, N, S, and 14 kinds of mineral elements were analyzed by AFS, EA, and ICP-AES, respectively. Spectral analysis (IR and UV) indicated Se-polysaccharides were typical glycoproteins. Morphological analyses of the samples were determined by SEM and AFM. In addition, the DPPH and superoxide radicals scavenging activities were also discussed to assess antioxidant activities of the samples, and Se-polysaccharides showed higher antioxidant activities compared to the ordinary polysaccharides.

Characterization of an Ebosin derivative produced by heterologous gene replacement in Streptomyces sp. 139

BACKGROUND

Ebosin is a novel exopolysaccharide (EPS) produced by Streptomyces sp. 139 and evidenced to possess an anti-rheumatic arthritis activity in vivo. The Ebosin biosynthesis gene cluster (ste) consists of 27 ORFs and ste7 has previously been demonstrated to code for a fucosyltransferase, which plays an essential role in the formation of repeating sugar units during Ebosin production. Aiming to generate derivatives of Ebosin for better activity, we replaced ste7 with a gene encoding for a glucosyltransferase (gtf) from Streptococcus thermophilus.

RESULTS

This alteration resulted in a novel Ebosin derivative (EPS-7 g) with its monosaccharide composition dramatically changed, especially in the proportion of glucose which increased from 1.1% (Ebosin) to 84.01% (EPS-7 g). In an ELISA analysis, EPS-7 g exhibited a higher binding activity for IL-1R, as a competitor of interleukin-1, than that of Ebosin. It also exhibited a higher inhibitory effect on the activity of IL-1β-converting enzyme and production of IL-1β in fibroblast-like synoviocytes (FLS). In addition, experiments with acute inflamed mice induced by croton oil showed a significantly higher anti-inflammatory activity of EPS-7 g compared with Ebosin.

CONCLUSIONS

The new Ebosin derivative EPS-7 g is more bioactive than Ebosin evaluated by a series of experiments. This is the first report demonstrating a modification of EPS structure via heterologous gene replacement in Streptomyces.

Selenium‑enriched exopolysaccharides produced by Enterobacter cloacae Z0206 alleviate adipose inflammation in diabetic KKAy mice through the AMPK/SirT1 pathway

Polysaccharides belong to a structurally diverse class of macromolecules, with the necessary flexibility for the precise regulatory mechanisms and high capacity for carrying biological information. On the basis of a previous study regarding the administration of selenium-enriched exopolysaccharides (Se-ECZ-EPS) produced by Enterobacter cloacae (E. cloacae) Z0206 which resulted in a reduction of blood glucose levels and showed significant anti-inflammatory and anti-diabetic effects, the present study was conducted to evaluate the effects and mechanism of EPS on the alleviation of fat inflammation in high-fat-diet (HFD) induced-diabetic KKAy mice. The HFD induced-diabetic KKAy mice were gavaged once daily with EPS (0.2 mg/g body weight) or distilled water, while the C57BL/6J mice were gavaged with distilled water. Six weeks later visceral adipose tissue (VAT) was collected for quantified polymerase chain reaction (qPCR) and western blot (WB) analysis. The results showed that following supplementation with EPS, interleukin (IL) 6, IL1β and tumor necrosis factor (TNF) α mRNA expression in VAT were significantly reduced, while Glut4, pAMPK and SirT1 protein expression were markedly increased when compared with KKAy mice gavaged with water. Furthermore, ATGL and HSL mRNA were also significantly decreased. Subsequently, 3T3-L1 adipocytes were treated with insulin to induce insulin resistance to determine the mechanism by which EPS affects inflammation. Following the treatment of adipocytes with 100 nM insulin for 8 h, IL6 and TNFα mRNA expression were significantly increased, while the content of glucose uptake and Glut4 protein expression were significantly decreased. When treated with 100 nM insulin and 0.1 mg/ml EPS, no significant change in IL6 and TNFα mRNA expression or glucose uptake were observed. However, when SirT1‑siRNA or AMPKα1-siRNA was transfected into the 3T3-L1 adipocytes prior to treatment with insulin and EPS, there was a significant increase in IL6 and TNFα mRNA abundance. In conclusion, VAT inflammation and lipolysis in HFD-induced KKAy mice were significantly decreased following EPS usage. Moreover, EPS may alleviate VAT inflammation primarily through the AMPK/SirT1 pathway.

Structural features and biological activities of the polysaccharides from Astragalus membranaceus

Recently, a great deal of interest has been developed to isolate and investigate novel bioactive components with health benefit effects from natural resources. The dried root of Astragalus membranaceus, one of the most popular health-promoting herbal medicines, has been used historically as an immunomodulating agent for the treatment of common cold, diarrhea, fatigue and anorexia for more than 2000 years. Modern phytochemistry and pharmacological experiments have proved that polysaccharide is one of the major active ingredients in the root of A. membranaceus with various important bioactivities, such as immunomodulation, antioxidant, antitumor, anti-diabetes, antiviral, hepatoprotection, anti-inflammation, anti-atherosclerosis, hematopoiesis and neuroprotection. The aim of the present review is to summarize previous and current references and give a comprehensive summary regarding the structural features and biological activities of A. membranaceus polysaccharides in order to provide new insight for further development of these macromolecules.

Anti-Inflammatory Effect of Ebosin on Rat Collagen-Induced Arthritis through Suppressing Production of Interleukin-1β, Interleukin-6 and Tumor Necrosis Factor-α

Reumatoid arthritis (RA) is an autoimmune disease which has been studied experimentally using a wide variety of animal models including collagen-induced arthritis (CIA). Using this CIA model we studied the therapeutic effects and mechanism of action of Ebosin, a novel exopolysaccharide produced by Streptomyces sp. 139, on arthritis. Ebosin at 200, 400 and 600 mg/kg/day was orally administered to rats respectively between day 10 and 30 after immunization with chicken type II collagen. With the treatment arthritic progression was remarkably suppressed. Levels of anti-type II collagen-specific antibody, IL-1β and TNF-α were significantly lower in the Ebosin-treated CIA rats compared with the untreated controls. In cultured fibroblast-like synoviocytes (FLS), remarkable suppression of IL-1β, TNF-α and IL-6 production was detected at both protein and mRNA levels after Ebosin administration. Ebosin also resulted in lower activities of IL-1β-converting enzyme and TNF-α-converting enzyme in FLS. Based on these results, it is concluded that development and progression of rat CIA can be significantly suppressed by orally-administrated Ebosin. The therapeutic effect may be attributed to its inhibition in the production of IL-1β, TNF-α and IL-6 in the CIA rats.

Anti-diabetic activity of Vaccinium bracteatum Thunb. leaves' polysaccharide in STZ-induced diabetic mice

Vaccinium bracteatum Thunb. (VBT) is a traditional Chinese herbal medicine. The anti-diabetic activity of VBT leaves' polysaccharide (VBTLP) is studied in this paper. The results indicated VBTLP had a dose-dependent decrease on the blood glucose (BG) level, and the time effect of VBTLP on BG level was also significant. The insulin level of high dose group (HDG) was significantly higher (p<0.05) than that of model control (MC) group. Compared to MC, HDG and lose dose group (LDG) had significantly lower (p<0.05) TC and LDL-C levels, however, TG and HDL-C levels are similar. Compared to non-diabetic control (NC), HDG and LDG had similar plasma lipid levels except for higher LDL-C level. Although body weights of LDG and HDG were significant lower (p<0.05) than that of NC from week 2 to week 6, they were similar to that of PC. The results indicate VBTLP possesses a potential hypoglycemic effect in streptozotocin-induced diabetic mice.

Antitumor activity of hyaluronic acid-selenium nanoparticles in Heps tumor mice models

In this study, hyaluronic acid-selenium (HA-Se) nanoparticles as novel complexes were synthesized and their antitumor activities in vivo were investigated. The mice inoculated with Heps tumor were orally administered with HA-Se nanoparticles at 86.45 mg/kg (H) and 4.32 mg/kg (L) body weights as high and low doses respectively (2.20% selenium content in the HA-Se nanoparticles samples by ICP-AES) for 10 days. The transmission electron microscopy (TEM) results indicated that the HA-Se nanoparticles were spherical with mean size of 50-70 nm. The HA-Se nanoparticles could significantly reduce tumor weights at the tumor inhibition ratios of 46.92% (H) and 49.12% (L) respectively. However, in the 5-fluorouracil positive group (25 mg/kg), the tumor inhibition ratio was 61.71%. From the study, the HA-Se nanoparticles (4.32 mg/kg) significantly increased thymus and spleen relative weights, enhanced the activities of superoxide dismutase (SOD), reduced the formation of malondialdehyde (MDA) and the activities of aspartate transaminase, alanine transaminase and crea in Heps tumor mice. The results of the study indicated that the HA-Se nanoparticles are potential antitumor candidate for cancer treatment.

Optimization of synthesis, characterization and cytotoxic activity of Seleno-Capparis spionosa L. polysaccharide

In this study, an experiment was designed to optimize the synthesis of seleno-Capparis spionosa L. polysaccharide (Se-CSPS) by response surface methodology. Three independent variables (reaction time, reaction temperature and ratio of Na(2)SeO(3) to CSPS) were tested. Furthermore, the thermal stability, particle size, shape and cytotoxic activity of Se-CSPS in vitro were investigated. The optimum reaction conditions were obtained shown as follows: reaction time 7.5 h, reaction temperature 71 °C, and ratio of Na(2)SeO(3) to CSPS 0.9 g/g. Under these conditions, the Se content in Se-CSPS reached 5.547 mg/g, which was close to the predicted value (5.518 mg/g) by the model. The thermal stability, particle size and shape of Se-CSPS were significantly different from those of CSPS. Additionally, a MTT assay indicated that the Se-CSPS could inhibit the proliferation of human gastric cancer SGC-7901 cells in a dose-dependent manner.