The Effects of Staphylococci on the Degranulation of Human Mast Cell-1

Atopic dermatitis (AD) is characterized by disturbances in epidermal barrier functions and the hyperactive immune response. Staphylococcus aureus (S. aureus) can be cultured from 90% of AD skin lesions and can exacerbate or contribute to the persistent skin inflammation in AD by secreting toxins with superantigenic properties. Superantigens can induce mast cell (MC) degranulation after penetrating the epidermal barrier. The role of MCs in AD is suggested by the increase in the MC number and MC activation. MCs are activated for degranulation and mediator release by allergens that cross-link IgE molecules or by microbial products. Therefore, MCs may be critically involved in the pathogenesis of AD. However, the understanding mechanisms of MC degranulation by S. aureus in relation to AD have still not been fully elucidated. In this study, we found that live S. aureus or methicillin-resistant S. aureus (MRSA) but not heat-killed bacteria induced MC degranulation. The heat-treatment partially inhibited MC degranulation by conditioned media (CM) of S. aureus or MRSA. The calcium chelator ethylene glycol tetraacetic acid (EGTA) did not block MC degranulation induced by live S. aureus or MRSA, but EGTA-treatment partially inhibited MC degranulation by CM from S. aureus or MRSA. These results suggest that live S. aureus and MRSA can degranulate MCs via direct interaction which may be important role in AD.

The Effects of Staphylococci on the Degranulation of Human Mast Cell-1

Atopic dermatitis (AD) is characterized by disturbances in epidermal barrier functions and the hyperactive immune response. Staphylococcus aureus (S. aureus) can be cultured from 90% of AD skin lesions and can exacerbate or contribute to the persistent skin inflammation in AD by secreting toxins with superantigenic properties. Superantigens can induce mast cell (MC) degranulation after penetrating the epidermal barrier. The role of MCs in AD is suggested by the increase in the MC number and MC activation. MCs are activated for degranulation and mediator release by allergens that cross-link IgE molecules or by microbial products. Therefore, MCs may be critically involved in the pathogenesis of AD. However, the understanding mechanisms of MC degranulation by S. aureus in relation to AD have still not been fully elucidated. In this study, we found that live S. aureus or methicillin-resistant S. aureus (MRSA) but not heat-killed bacteria induced MC degranulation. The heat-treatment partially inhibited MC degranulation by conditioned media (CM) of S. aureus or MRSA. The calcium chelator ethylene glycol tetraacetic acid (EGTA) did not block MC degranulation induced by live S. aureus or MRSA, but EGTA-treatment partially inhibited MC degranulation by CM from S. aureus or MRSA. These results suggest that live S. aureus and MRSA can degranulate MCs via direct interaction which may be important role in AD.

Bacillus spp. or Bacillus spp.-Derived Membrane Vesicles Induce the Intrinsic Pathways of Apoptosis of Human Colon Cancer Cell Lines

The striking increase in colorectal cancer (CRC) has shown the great fatality in Korea for more than 15 years. The leading edge of this rising incidence rate is mainly due to the people's dietary changes in Korea. Some studies have reported that the dietary fiber does not have significant cytotoxic effects on CRC cells, which contrasts to the effects of probiotics. It gives a positive evaluation that the nonpathogenic spore-forming Bacillus species among the probiotics including fermented bacteria might have optimistic effects on CRC incidence rate. Recently, we isolated Bacillus lentus (BL) from Korean soybean fermented food. BL showed the cytotoxic effect on human colon carcinoma cell lines HCT116 and SW480. Interestingly, BL did not have effect on human dermal fibroblast cells and human hepatoma cell line HepG2. It suggested that BL has the target cell-specific cytotoxicity toward human colon carcinoma cells. To clarify the death signaling pathway underlying the BL-induced apoptosis in cancer cells, we analyzed the expression of caspases, Bax and Bcl-2 by western blotting. The apoptotic effects by cytotoxic elements were executed by direct BL contact or membrane-derived vesicles isolated from BL. Treatment of HCT116 with BL activated caspase-9, -3 and increased cleavage form of poly (ADP-ribose) polymerase (PARP). However, caspase-8 activity was not increased by BL. BL-activated intrinsic pathway increased the pro-apoptotic Bax, decreased the anti-apoptotic Bcl-2 proteins on mitochondria, disrupted the mitochondrial membrane potential, and then released the cytochrome c from mitochondria. The membrane-derived vesicles (MVs) from BL induced apoptosis of the HCT116. Here, we propose that BL as a strong candidate for the development of apoptosis-specific anti-tumor agent will give great contribution to the understandings of the tumor-microbe interdisciplinary areas.

Characterization of an Anti-gout Xanthine Oxidase Inhibitor from Pleurotus ostreatus

We selected Pleurotus ostreatus from among several edible mushrooms because it has high anti-gout xanthine oxidase (XOD) inhibitory activity. The maximal amount of XOD inhibitor was extracted when the Pleurotus ostreatus fruiting body was treated with distilled water at 40degrees C for 48 hr. The XOD inhibitor thus obtained was purified by Sephadex G-50 gel permeation chromatography, ultrafiltration, C18 solid phase extraction chromatography and reverse-phase high-performance liquid chromatography with 3% of solid yield, and its XOD inhibitory activity was 0.9 mg/mL of IC50. The purified XOD inhibitor was a tripeptide with the amino acid sequence phenylalanine-cysteine-histidine and a molecular weight of 441.3 Da. The XOD inhibitor-containing ultrafiltrates from Pleurotus ostreatus demonstrated dose-dependent anti-gout effects in a Sprague-Dawley rat model of potassium oxonate-induced gout, as shown by decreased serum urated levels at doses of 500 and 1,000 mg/kg, although the effect was not as great as that achieved with the commercial anti-gout agent, allopurinol when administered at a dose of 50 mg/kg.

Growth Characteristics and Physiological Functionality of Yeasts in Pear Marc Extracts

Kluyveromyces fragilis KCTC 7260 and Saccharomyces cerevisiae KCTC 7904, which both grew well in pear marc extract, were selected and their growth profiles and physiological functionalities were determined. Both of the selected yeasts established maximal growth by 20 hr of cultivation at 30degrees C in pear marc extract. The cell-free extracts showed high antihypertensive angiotensin I-converting enzyme inhibitory activity of 68.9% and 52.1%, respectively. The extracts also displayed 9.2 U/mL and 12.0 U/mL of protease activity, respectively.