Toxicological and immunomodulatory assessments of botryosphaeran (β-glucan) produced by Botryosphaeria rhodina RCYU 30101

Toxicological and immunomodulatory activities of botryosphaeran (BR), a newly emerged β-glucan that comprises a β-(1→3) backbone and β-(1→6) branched glucose residues were assessed. BR was 1.82 × 10⁶ Da (M.W.) estimated by reversely-linear equation constructed by regression of logarithms of standard polysaccharides and their retention times of gel permeation chromatography. Sprague-Dawley rats were daily gavage-administered with BR at doses of 0, 1.25, 12.5, and 125 mg/kg body weight (BW) for 28 d. Serum hematological and biochemical analysis of all treatment were all within normal ranges. Mitogen-stimulated lymphoblastogenesis of spleno-lymphocytes was enhanced by BR at doses of 1.25 and 12.5 mg/kg BW. Through in vitro comparative assessments, RAW 264.7 macrophage (RAW) cells were treated with BR and two commercial β-glucans, zymosan (ZY) and barley β-glucan (GB), to characterize their relative immunomodulatory properties. All three β-glucans stimulated phagocytosis on fluorescence-labeled Escherichia coli. At dose levels from 5 to 200 μg/mL for 24 h, nitric oxide produced by BR- and ZY-treated cells were higher than those produced by GB-treated and control groups. BR, ZY but GB also stimulated RAW cells in producing TNF-α. The results demonstrate that BR is toxicologically accepted and features as a potent immunomodulator.     

The associations between labor and delivery mode and maternal and placental oxidative stress

To study oxidative stress differences between women with normal vaginal deliveries (VD) and those with elective cesarean sections without labor (CS), total antioxidant capacity (TAC), erythrocyte glutathione peroxidase (GPX) and superoxide dismutase (SOD) activity, 8-isoprostane, nitrotyrosine and 8-hydroxydeoxyguanosine (8-OHdG) in blood, urine, and placental samples were assessed. The VD group had significantly higher placental 8-isoprostane and 8-OHdG levels as well as greater plasma TAC and 8-OHdG levels and lower erythrocyte SOD activity in umbilical venous blood. Women with VD exhibited differential changes in maternal oxidative stress before and after delivery compared with women with CS. Furthermore, we found that repetitive hypoxia-reoxygenation increased the 8-isoprostane and 8-OHdG levels in villous explants compared with the normoxic controls. Together, these results indicate that labor is associated with increased placental oxidative stress and has an influence on maternal oxidative stress. Therefore, women with VD exhibit different oxidative stress indicators than do those with CS.     

Regenerative potentials of platelet-rich plasma enhanced by collagen in retrieving pro-inflammatory cytokine-inhibited chondrogenesis

This study was undertaken to evaluate the role of collagen matrix to enhance platelet-rich plasma (PRP) effects on pro-inflammatory cytokine-induced arthritic model. We have previously demonstrated the highly regenerative roles of PRP to restore disc degeneration and osteoporosis. In this study, PRP modulated by collagen matrix was used as a regenerative and anti-inflammatory mediator to rescue the chondrocyte degeneration induced by pro-inflammatory cytokines IL-1β (10 ng/ml)+TNF-α (20 ng/ml). First, the MTT result indicated that 1 ng/ml TGF-β1 in PRP showed an optimal dosage for chondrocytes proliferation. The chondrogenic-specific gene expressions were rescued by PRP from the inhibition of IL-1β+TNF-α, especially under the modulation of collagen matrix. The inflammatory molecules activated by IL-1β+TNF-α were also significantly diminished by PRP with collagen matrix. The membrane receptors integrin α1β1 and CD44 were strongly inhibited by IL-1β+TNF-α, while this inhibition was then recovered by PRP in collagen coating condition. In a 3D model encapsulated with collagen, PRP-induced chondrogenesis were highly enhanced, such as strong restoration of type II collagen and proteoglycan from the inhibition of IL-1β+TNF-α. The result indicated that collagen matrix enhances the effect of PRP on chondrogenesis in response to pro-inflammatory cytokines. The combination of PRP and collagen matrix might facilitate a physiological microenvironment beneficial for maintaining chondrocyte homeostasis and represents an advanced osteoarthritis therapy for clinical applications.     

Biochemical characterisation and novel classification of monofunctional S-adenosylmethionine decarboxylase of Plasmodium falciparum

Plasmodium falciparum like other organisms is dependent on polyamines for proliferation. Polyamine biosynthesis in these parasites is regulated by a unique bifunctional S-adenosylmethionine decarboxylase/ornithine decarboxylase (PfAdoMetDC/ODC). Only limited biochemical and structural information is available on the bifunctional enzyme due to the low levels and impurity of an instable recombinantly expressed protein from the native gene. Here we describe the high level expression of stable monofunctional PfAdoMetDC from a codon-harmonised construct, which permitted its biochemical characterisation indicating similar catalytic properties to AdoMetDCs of orthologous parasites. In the absence of structural data, far-UV CD showed that at least on secondary structure level, PfAdoMetDC corresponds well to that of the human protein. The kinetic properties of the monofunctional enzyme were also found to be different from that of PfAdoMetDC/ODC as mainly evidenced by an increased K(m). We deduced that complex formation of PfAdoMetDC and PfODC could enable coordinated modulation of the decarboxylase activities since there is a convergence of their k(cat) and lowering of their K(m). Such coordination results in the aligned production of decarboxylated AdoMet and putrescine for the subsequent synthesis of spermidine. Furthermore, based on the results obtained in this study we propose a new AdoMetDC subclass for plasmodial AdoMetDCs.