Beneficial effects of antioxidative lactic acid bacteria.

Oxidative stress is caused by exposure to reactive oxygen intermediates. The oxidative damage of cell components such as proteins, lipids, and nucleic acids one of the important factors associated with diabetes mellitus, cancers and cardiovascular diseases. This occurs as a result of imbalance between the generations of oxygen derived radicals and the organism's antioxidant potential. The amount of oxidative damage increases as an organism ages and is postulated to be a major causal factor of senescence. To date, many studies have focused on food sources, nutrients, and components that exert antioxidant activity in worms, flies, mice, and humans. Probiotics, live microorganisms that when administered in adequate amounts provide many beneficial effects on the human health, have been attracting growing interest for their health-promoting effects, and have often been administered in fermented milk products. In particular, lactic acid bacteria (LAB) are known to conferre physiologic benefits. Many studies have indicated the antioxidative activity of LAB. Here we review that the effects of lactic acid bacteria to respond to oxidative stress, is connected to oxidative-stress related disease and aging.

Lactobacillus helveticus SBT2171 inhibits lymphocyte proliferation by regulation of the JNK signaling pathway.

Lactobacillus helveticus SBT2171 (LH2171) is a lactic acid bacterium with high protease activity and used in starter cultures in the manufacture of cheese. We recently reported that consumption of cheese manufactured using LH2171 alleviated symptoms of dextran sodium sulfate (DSS)-induced colitis in mice. In this study, we have examined whether LH2171 itself exerts an inhibitory effect on the excessive proliferation of lymphocytes. We found that LH2171 inhibited the proliferation of LPS-stimulated mouse T and B cells, and the human lymphoma cell lines, Jurkat and BJAB. Cell cycle analysis showed an accumulation of LH2171-treated BJAB cells in the G2/M phase. Further, phosphorylation of c-Jun N-terminal kinase (JNK) and c-Jun was reduced by LH2171 in BJAB cells. Subsequently, expression of cell division cycle 2 (CDC2), regulated by the JNK signaling pathway and essential for G2/M phase progression, was inhibited by LH2171. It was also demonstrated that intraperitoneal administration of LH2171 strongly alleviated symptoms of collagen-induced arthritis (CIA) in mice. These findings suggest that LH2171 inhibits the proliferation of lymphocytes through a suppression of the JNK signaling pathway and exerts an immunosuppressive effect in vivo.

Oral administration of Lactobacillus gasseri SBT2055 is effective for preventing influenza in mice.

The Lactobacillus gasseri SBT2055 (LG2055) is a probiotic lactic acid bacterium with properties such as bile tolerance and ability to improve the intestinal environment. In this study, we established that the oral administration of LG2055 exhibits efficacy to protect mice infected with the influenza virus A/PR8. The body weight losses were lower with the LG2055 administration after the PR8 virus infection. At 5 days after the infection, the virus titer was significantly decreased as was the amount of produced IL-6 in the lung tissue, the number of total cells in the bronchoalveolar lavage fluid was reduced by the LG2055 administration. The expression of the Mx1 and Oas1a genes, critical for the viral clearance in the lung tissues was increased by the pre-treatment with LG2055. These findings suggest that the LG2055 administration is effective for the protection against influenza A virus infection by the down-regulation of viral replication through the induction of antiviral genes expression.

[Impaired expression of Act1mRNA in B cells of patients with Sjögren's syndrome].

Sjögren's syndrome (SS) is a systemic autoimmune disorder characterized by profound lymphocytic infiltration into the lacrimal and salivary glands, thereby diminished secretory function. B cell hyper-activation is a predominant feature of SS related to hypergammaglobulinemia and production of autoantibodies. The adaptor molecule NF-kB activator 1 (Act1) plays an important role in the homeostasis of B cells by attenuating CD40 and B cell-activating factor belonging to the tumor necrosis factor family receptor (BAFFR) signaling. Act1-deficient mice develop autoimmune manifestations similar to SS, which are hypergammaglobulinemia, high levels of anti-SSA and anti-SSB autoantibodies. In this study, to investigate the role of Act1 in the pathogenesis of SS, we examined Act1mRNA expressions in B cells from patients with SS and discussed the association of Act1 with parameters and clinical manifestations of SS. We showed the low level of Act1mRNA expression in patients with SS and reciprocal association of Act1 with serum IgG level. Diminished Act1mRNA expression in SS may be associated with B cell hyperactivity and elevated immunoglobulin production in SS by uncontrolled B cell activation signal through CD40 and BAFFR.

Nicked {beta}2-glycoprotein I binds angiostatin 4.5 (plasminogen kringle 1-5) and attenuates its antiangiogenic property.

Angiostatin was first discovered as a plasminogen fragment with antitumor/antiangiogenic property. One of the angiostatin isoforms, that is, angiostatin 4.5 (AS4.5), consisting of plasminogen kringle 1 to 4 and a most part of kringle 5, is produced by autoproteolysis and present in human plasma. beta2-glycoprotein I (beta2GPI) is proteolytically cleaved by plasmin in its domain V (nicked beta2GPI), resulting in binding to plasminogen. Antiangiogenic properties have been recently reported in nicked beta2GPI as well as in intact beta2GPI at higher concentrations. In the present study, we found significant binding of nicked beta2GPI to AS4.5 (K(D) = 3.27 x 10(6) M(-1)). Via this binding, nicked beta2GPI attenuates the antiangiogenic functions of AS4.5 in the proliferation of arterial/venous endothelial cells, in the extracellular matrix invasion and the tube formation of venous endothelial cells, and in vivo angiogenesis. In contrast, intact beta2GPI does not bind to AS4.5 or inhibit its antiangiogenic activity. Thus, nicked beta2GPI exerts dual effects on angiogenesis, that is, nicked beta2GPI promotes angiogenesis in the presence of AS4.5, whereas nicked beta2GPI inhibits angiogenesis at concentrations high enough to neutralize AS4.5. Our data suggest that plasmin-nicked beta2GPI promotes angiogenesis by interacting with plasmin-generated AS4.5 in sites of increased fibrinolysis such as thrombus.

Peritoneal mesothelial cells as a target of local aldosterone action: upregulation of connective tissue growth factor expression via serum- and glucocorticoid-inducible protein kinase 1.

BACKGROUND/AIMS: Peritoneal fibrosis can lead to the discontinuation of continuous ambulatory peritoneal dialysis. The present study investigated the direct effect of aldosterone, which influences tissue fibrosis, and its cellular mechanism using cultured rat peritoneal mesothelial cells (RPMCs). MATERIALS AND METHODS: The expression of aldosterone synthase (CYP11B2), mineralocorticoid receptors, 11beta-hydroxysteroid dehydrogenase 2, serum- and glucocorticoid-inducible protein kinase 1 (SGK1) and connective tissue growth factor (CTGF) was evaluated using reverse transcriptase-polymerase chain reaction and Western blot. The ability of RPMCs to produce aldosterone was examined by enzyme immunoassay. Small interfering RNA of SGK1 was transfected to determine the role of SGK1. RESULTS: CYP11B2, mineralocorticoid receptors and 11beta-hydroxysteroid dehydrogenase 2 were expressed in RPMCs. The release of aldosterone from RPMCs into the culture medium was confirmed. Stimulation of RPMCs with the addition of aldosterone significantly increased SGK1 expression and phosphorylation and CTGF upregulation, and these effects were completely inhibited by the mineralocorticoid receptor antagonist spironolactone. SGK1 gene silencing abrogated aldosterone-induced CTGF expression. CONCLUSION: The local aldosterone system exists and acts directly as a profibrotic factor in the peritoneal mesothelium.