Differential immune-stimulatory effects of LTAs from different lactic acid bacteria via MAPK signaling pathway in RAW 264.7 cells

Immunostimulatory activity of lipoteichoic acid with three fatty acid residues derived from Limosilactobacillus antri JCM 15950T

Some strains of lactic acid bacteria can regulate the host's intestinal immune system. Bacterial cells and membrane vesicles (MVs) of Limosilactobacillus antri JCM 15950T promote immunoglobulin A (IgA) production in murine Peyer's patch cells via toll-like receptor (TLR) 2. This study aimed to investigate the role of lipoteichoic acid (LTA), a ligand of TLR2, in the immunostimulatory activity of these bacterial cells and their MVs. LTA extracted from bacterial cells was purified through hydrophobic interaction chromatography and then divided into fractions LTA1 and LTA2 through anion-exchange chromatography. LTA1 induced greater interleukin (IL)-6 production from macrophage-like RAW264 cells than LTA2, and the induced IL-6 production was suppressed by TLR2 neutralization using an anti-TLR2 antibody. The LTAs in both fractions contained two hexose residues in the glycolipid anchor; however, LTA1 was particularly rich in triacyl LTA. The free hydroxy groups in the glycerol phosphate (GroP) repeating units were substituted by d-alanine (d-Ala) and α-glucose in LTA1, but only by α-glucose in LTA2. The dealanylation of LTA1 slightly suppressed IL-6 production in RAW264 cells, whereas deacylation almost completely suppressed IL-6 production. Furthermore, IL-6 production induced by dealanylated LTA1 was markedly higher than that induced by dealanylated LTA2. These results indicated that the critical moieties for the immunostimulatory activity of L. antri-derived LTA were the three fatty acid residues rather than the substitution with d-Ala in GroP. LTA was also detected in MVs, suggesting that the triacyl LTA, but not the diacyl LTA, translocated to the MVs and conferred immunostimulatory activity.

IMPORTANCE

Some lactic acid bacteria activate the host intestinal immune system via toll-like receptor (TLR) 2. Lipoteichoic acid (LTA) is a TLR2 ligand; however, the moieties of LTA that determine its immunostimulatory activity remain unclear because of the wide diversity of LTA partial structures. We found that Limosilactobacillus antri JCM 15950T has three types of LTAs (triacyl, diacyl, and monoacyl LTAs). Specifically, structural analysis of the LTAs revealed that triacyl LTA plays a crucial role in immunostimulation and that the fatty acid residues are essential for the activity. The three acyl residues are characteristic of LTAs from many lactic acid bacteria, and our findings can explain the immunostimulatory mechanisms widely exhibited by lactic acid bacteria. Furthermore, the immunostimulatory activity of membrane vesicles released by L. antri JCM 15950T is due to the transferred LTA, demonstrating a novel mechanism of membrane vesicle-mediated immunostimulation.

Exopolysaccharide from Lacticaseibacillus paracasei alleviates gastritis in Helicobacter pylori-infected mice by regulating gastric microbiota

Introduction

Many probiotics have the ability to produce extracellular polysaccharides (EPS). EPS derived from these probiotics has been confirmed to regulate the host intestinal microecological balance and alleviate the symptoms of diseases caused by gastrointestinal microecological imbalance.

Results

Lactic acid bacteria (LAB) strain with good exopolysaccharide (EPS) producing ability, namely, Lacticaseibacillus paracasei ZFM54 (L. paracasei ZFM54) was screened. The fermentation conditions of L. paracasei ZFM54 for EPS production were optimized. The EPS54 was characterized by chemical component and monosaccharide composition determination, UV, FT-IR and NMR spectra analysis. Cango red, SEM, AFM and XRD analysis were conducted to characterize the structure of EPS54. The EPS54 effectively reduced the colonization of Helicobacter pylori to AGS cells and recovered the cell morphology. EPS54 could also effectively alleviate the gastritis in the H. pylori-infected mice by down-regulating the mRNA expression levels of pro-inflammatory cytokines IL-6, IL-8, IL-1β and TNF-α and up-regulating the mRNA expression of inflammatory cytokine IL-10 in gastric cells. EPS54 was also found to be able to positively regulate the structure of gastric microbiota.

Conclusion

The EPS 54 from L. paracasei ZFM54 can alleviate gastritis in H. pylori-infected mice by modulating the gastric microbiota.

Immune-Stimulating Potential of Lacticaseibacillus rhamnosus LM1019 in RAW 264.7 Cells and Immunosuppressed Mice Induced by Cyclophosphamide

Probiotics, including Lacticaseibacillus rhamnosus (L. rhamnosus), have gained recognition for their potential health benefits, such as enhancing immune function, maintaining gut health, and improving nutrient absorption. This study investigated the effectiveness of L. rhamnosus LM1019 (LM1019) in enhancing immune function. In RAW 264.7 cells, LM1019 demonstrated dose-dependent immune stimulation by increasing nitric oxide production, gene expression of proinflammatory cytokines, and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These effects were mediated through the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) translocation without inducing cytotoxicity. Furthermore, orally administered LM1019 was evaluated in immunosuppressed mice induced by cyclophosphamide (CTX). High-dose administration of LM1019 significantly increased the subpopulations of lymphocytes, specifically helper T cells (CD4+), as well as two subtypes of natural killer (NK) cells, namely, IFN-γ+ and granzyme B+ NK cells. Additionally, LM1019 at a high dose led to elevated levels of proinflammatory cytokines, including IFN-γ and IL-12, compared to CTX-treated mice. These findings highlight the potential of LM1019 in enhancing the immune system. The study contributes to the growing body of research on the beneficial effects of probiotics on immune function.

Polysaccharide BAP1 of Bifidobacterium adolescentis CCDM 368 is a biologically active molecule with immunomodulatory properties

Bifidobacteria are among the most common bacteria used for their probiotic properties and their impact on the maturation and function of the immune system has been well-described. Recently, scientific interest is shifting from live bacteria to defined bacteria-derived biologically active molecules. Their greatest advantage over probiotics is the defined structure and the effect independent of the viability status of the bacteria. Here, we aim to characterize Bifidobacterium adolescentis CCDM 368 surface antigens that include polysaccharides (PSs), lipoteichoic acids (LTAs), and peptidoglycan (PG). Among them, Bad368.1 PS was observed to modulate OVA-induced cytokine production in cells isolated from OVA-sensitized mice by increasing the production of Th1-related IFN-γ and inhibition of Th2-related IL-5 and IL-13 cytokines (in vitro). Moreover, Bad368.1 PS (BAP1) is efficiently engulfed and transferred between epithelial and dendritic cells. Therefore, we propose that the Bad368.1 PS (BAP1) can be used for the modulation of allergic diseases in humans. Structural studies revealed that Bad368.1 PS has an average molecular mass of approximately 9,99 × 10⁶ Da and it consists of glucose, galactose, and rhamnose residues that are creating the following repeating unit: →2)-β-D-Glcp-1→3-β-L-Rhap-1→4-β-D-Glcp-1→3-α-L-Rhap-1→4-β-D-Glcp-1→3-α-D-Galp-(1→_n.

Lactobacillus plantarum postbiotics trigger AMPK-dependent autophagy to suppress Salmonella intracellular infection and NLRP3 inflammasome activation

We previously found that Lactobacillus plantarum (LP)-derived postbiotics protected animals against Salmonella infection, but the molecular mechanism remains obscure. This study clarified the mechanisms from the perspective of autophagy. Intestinal porcine epithelial cells (IPEC-J2) were pretreated with LP-derived postbiotics (the culture supernatant, LPC; or heat-killed bacteria, LPB), and then challenged with Salmonella enterica Typhimurium (ST). Results showed that LP postbiotics markedly triggered autophagy under ST infection, as indicated by the increased LC3 and Beclin1 and the decreased p62 levels. Meanwhile, LP postbiotics (particularly LPC) exhibited a strong capacity of inhibiting ST adhesion, invasion and replication. Pretreatment with the autophagy inhibitor 3-methyladenine (3-MA) led to a significant decrease of autophagy and the aggravated infection, indicating the importance of autophagy in LP postbiotics-mediated Salmonella elimination. LP postbiotics (especially LPB) significantly suppressed ST-induced inflammation by modulating inflammatory cytokines (the increased interleukin (IL)-4 and IL-10, and decreased tumor necrosis factor-α (TNF), IL-1β, IL-6 and IL-18). Furthermore, LP postbiotics inhibited NOD-like receptor protein 3 (NLRP3) inflammasome activation, as evidenced by the decreased levels of NLRP3, Caspase-1 and apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC). Deficits in autophagy resulted in an increase of inflammatory response and inflammasome activation. Finally, we found that both LPC and LPB triggered AMP-activated protein kinase (AMPK) signaling pathway to induce autophagy, and this was further confirmed by AMPK RNA interference. The intracellular infection and NLRP3 inflammasome were aggravated after AMPK knockdown. In summary, LP postbiotics trigger AMPK-mediated autophagy to suppress Salmonella intracellular infection and NLRP3 inflammasome in IPEC-J2 cells. Our findings highlight the effectiveness of postbiotics, and provide a new strategy for preventing Salmonella infection.

Physiology, quorum sensing, and proteomics of lactic acid bacteria were affected by Saccharomyces cerevisiae YE4

The interaction mode between lactic acid bacteria (LAB) and yeast in a fermentation system directly determines the quality of the products, thus understanding their mode of interaction can improve product quality. The present study investigated the effects of Saccharomyces cerevisiae YE4 on LAB from the perspectives of physiology, quorum sensing (QS), and proteomics. The presence of S. cerevisiae YE4 slowed down the growth of Enterococcus faecium 8-3 but had no significant effect on acid production or biofilm formation. S. cerevisiae YE4 significantly reduced the activity of autoinducer-2 at 19 h in E. faecium 8-3 and at 7-13 h in Lactobacillus fermentum 2-1. Expression of the QS-related genes luxS and pfs was also inhibited at 7 h. Moreover, a total of 107 E. faecium 8-3 proteins differed significantly in coculture with S. cerevisiae YE4-these proteins are involved in metabolic pathways including biosynthesis of secondary metabolites; biosynthesis of amino acids; alanine, aspartate, and glutamate metabolism; fatty acid metabolism; and fatty acid biosynthesis. Among them, proteins involved in cell adhesion, cell wall formation, two-component systems, and ABC transporters were detected. Therefore, S. cerevisiae YE4 might affect the physiological metabolism of E. faecium 8-3 by affecting cell adhesion, cell wall formation, and cell-cell interactions.

Gut microbiota in ischemic stroke: Where we stand and challenges ahead

Gut microbiota is increasingly recognized to affect host health and disease, including ischemic stroke (IS). Here, we systematically review the current understanding linking gut microbiota as well as the associated metabolites to the pathogenesis of IS (e.g., oxidative stress, apoptosis, and neuroinflammation). Of relevance, we highlight that the implications of gut microbiota-dependent intervention could be harnessed in orchestrating IS.

Levilactobacillus brevis KU15151 Inhibits Staphylococcus aureus Lipoteichoic Acid-Induced Inflammation in RAW 264.7 Macrophages

Inflammation is a host defense response to harmful agents, such as pathogenic invasion, and is necessary for health. Excessive inflammation may result in the development of inflammatory disorders. Levilactobacillus brevis KU15151 has been reported to exhibit probiotic characteristics and antioxidant activities, but the effect of this strain on inflammatory responses has not been determined. The present study aimed to investigate the anti-inflammatory potential of L. brevis KU15151 in Staphylococcus aureus lipoteichoic acid (aLTA)-induced RAW264.7 macrophages. Treatment with L. brevis KU15151 reduced the production of nitric oxide and prostaglandin E₂ by suppressing the expression of inducible nitric oxide synthase and cyclooxygenase-2. Additionally, the production of proinflammatory cytokines including tumor necrosis factor-α, interleukin (IL)-6, and IL-1β, decreased after treatment with L. brevis KU15151 in aLTA-stimulated RAW 264.7 cells. Furthermore, this strain alleviated the activation of nuclear factor-κB and mitogen-activated protein kinase signaling pathways. Moreover, the generation of reactive oxygen species was downregulated by treatment with L. brevis KU15151. These results demonstrate that L. brevis KU15151 possesses an inhibitory effect against aLTA-mediated inflammation and may be employed as a functional probiotic for preventing inflammatory disorders.

Protective Effects of a Novel Lactobacillus brevis Strain with Probiotic Characteristics against Staphylococcus aureus Lipoteichoic Acid-Induced Intestinal Inflammatory Response

Probiotics can effectively modulate host immune responses and prevent gastrointestinal diseases. The objective of this study was to investigate the probiotic characteristics of Lactobacillus brevis KU15152 isolated from kimchi and its protective potential against intestinal inflammation induced by Staphylococcus aureus lipoteichoic acid (aLTA). L. brevis KU15152 exhibited a high survival rate in artificial gastric and bile environments. Additionally, the adhesion capability of the strain to HT-29 cells was higher than that of L. rhamnosus GG. L. brevis KU15152 did not produce harmful enzymes, such as β-glucuronidase, indicating that it could be used as a potential probiotic. The anti-inflammatory potential of L. brevis KU15152 was determined in HT-29 cells. Treatment with L. brevis KU15152 suppressed the production of interleukin-8 without inducing significant cytotoxicity. The downregulatory effects of L. brevis KU15152 were involved in the suppression of nuclear factor-kappa B activation mediated by the extracellular signal-regulated kinase and Akt signaling pathways. Collectively, these data suggest that L. brevis KU15152 can be used in developing therapeutic and prophylactic products to manage and treat aLTA-induced intestinal damage.

Lipoteichoic Acid from Lacticaseibacillus rhamnosus GG Modulates Dendritic Cells and T Cells in the Gut

Lipoteichoic acid (LTA) from Gram-positive bacteria exerts different immune effects depending on the bacterial source from which it is isolated. Lacticaseibacillus rhamnosus GG LTA (LGG-LTA) oral administration reduces UVB-induced immunosuppression and skin tumor development in mice. In the present work, we evaluate the immunomodulatory effect exerted by LGG-LTA in dendritic cells (DC) and T cells, both in vitro and in the gut-associated lymphoid tissue (GALT). During cell culture, LTA-stimulated BMDC increased CD86 and MHC-II expression and secreted low levels of pro and anti-inflammatory cytokines. Moreover, LTA-treated BMDC increased T cell priming capacity, promoting the secretion of IL-17A. On the other hand, in orally LTA-treated mice, a decrease in mature DC (lamina propria and Peyer’s patches) was observed. Concomitantly, an increase in IL-12p35 and IFN-γ transcription was presented (lamina propria and Peyer’s Patches). Finally, an increase in the number of CD103+ DC was observed in Peyer’s patches. Together, our data demonstrate that LGG-LTA activates DC and T cells. Moreover, we show that a Th1-biased immune response is triggered in vivo after oral LTA administration. These effects justify the oral LTA activity previously observed.

Differential Immunostimulatory Effects of Lipoteichoic Acids Isolated from Four Strains of Lactiplantibacillus plantarum

The intestinal health and immune modulatory effects of probiotics are well known. As with live bacteria, several studies demonstrating the ability of dead cells to improve gut health and immunity have suggested varying potentials for microbes to affect the human gut. The effect of dead microbes most likely derives from the cell wall of the microorganism. In this study, the functionality of lipoteichoic acid (LTA), a cell wall component, isolated from four stains of Lactiplantibacillus plantarum, K8, K88, K5-5, and K55-5, and the relationship between LTAs and their receptors were investigated. The four strains of L. plantarum have different LTA structures, which contributed to different immune activities in the immune cells. We confirmed that the different binding abilities with the host cell surface receptors, along with the differences in signal pathway, were due to the structural differences of the LTAs. LTA is an important postbiotic that induces various immunomodulatory actions.

ANALYSIS OF CARBOHYDRATES AND GLYCOCONJUGATES BY MATRIX-ASSISTED LASER DESORPTION/IONIZATION MASS SPECTROMETRY: AN UPDATE FOR 2015-2016

This review is the ninth update of the original article published in 1999 on the application of matrix-assisted laser desorption/ionization (MALDI) mass spectrometry to the analysis of carbohydrates and glycoconjugates and brings coverage of the literature to the end of 2016. Also included are papers that describe methods appropriate to analysis by MALDI, such as sample preparation techniques, even though the ionization method is not MALDI. Topics covered in the first part of the review include general aspects such as theory of the MALDI process, matrices, derivatization, MALDI imaging, fragmentation and arrays. The second part of the review is devoted to applications to various structural types such as oligo- and poly-saccharides, glycoproteins, glycolipids, glycosides and biopharmaceuticals. Much of this material is presented in tabular form. The third part of the review covers medical and industrial applications of the technique, studies of enzyme reactions and applications to chemical synthesis. The reported work shows increasing use of combined new techniques such as ion mobility and the enormous impact that MALDI imaging is having. MALDI, although invented over 30 years ago is still an ideal technique for carbohydrate analysis and advancements in the technique and range of applications show no sign of deminishing. © 2020 Wiley Periodicals, Inc.

Probiotic properties of novel probiotic Levilactobacillus brevis KU15147 isolated from radish kimchi and its antioxidant and immune-enhancing activities

This study was conducted to evaluate the probiotic properties and antioxidant activities of lactic acid bacteria strains including Levilactobacillus brevis KU15147 isolated from kimchi to determine their potential as a probiotic. The tolerance of all strains to gastric acid and bile salts was more than 90%. The strains did not produce a β-glucuronidase and survived following treatment with gentamicin, kanamycin, streptomycin, and ciprofloxacin. L. brevis KU15147 showed greater adhesion activity to HT-29 cells (6.38%) and its antioxidant activities were higher than those of other tested strains, showing values of 38.56%, 22%, and 23.82% in DPPH, ABTS, and β-carotene bleaching assays, respectively. Additionally, the relative expression intensities of induced nitric oxide synthase and tumor necrosis factor-α of L. brevis KU15147 were greater than those of other strains, suggesting that this strain can be applied in the health food or pharmaceutical industry as a novel probiotic strain.

Streptococcus pneumoniae, S. mitis, and S. oralis Produce a Phosphatidylglycerol-Dependent, ltaS-Independent Glycerophosphate-Linked Glycolipid

Lipoteichoic acid (LTA) is a Gram-positive bacterial cell surface polymer that participates in host-microbe interactions. It was previously reported that the major human pathogen Streptococcus pneumoniae and the closely related oral commensals S. mitis and S. oralis produce type IV LTAs. Herein, using liquid chromatography/mass spectrometry-based lipidomic analysis, we found that in addition to type IV LTA biosynthetic precursors, S. mitis, S. oralis, and S. pneumoniae also produce glycerophosphate (Gro-P)-linked dihexosyl (DH)-diacylglycerol (DAG), which is a biosynthetic precursor of type I LTA. cdsA and pgsA mutants produce DHDAG but lack (Gro-P)-DHDAG, indicating that the Gro-P moiety is derived from phosphatidylglycerol (PG), whose biosynthesis requires these genes. S. mitis, but not S. pneumoniae or S. oralis, encodes an ortholog of the PG-dependent type I LTA synthase, ltaS. By heterologous expression analyses, we confirmed that S. mitisltaS confers poly(Gro-P) synthesis in both Escherichia coli and Staphylococcus aureus and that S. mitisltaS can rescue the growth defect of an S. aureusltaS mutant. However, we do not detect a poly(Gro-P) polymer in S. mitis using an anti-type I LTA antibody. Moreover, Gro-P-linked DHDAG is still synthesized by an S. mitisltaS mutant, demonstrating that S. mitis LtaS does not catalyze Gro-P transfer to DHDAG. Finally, an S. mitisltaS mutant has increased sensitivity to human serum, demonstrating that ltaS confers a beneficial but currently undefined function in S. mitis. Overall, our results demonstrate that S. mitis, S. pneumoniae, and S. oralis produce a Gro-P-linked glycolipid via a PG-dependent, ltaS-independent mechanism.

IMPORTANCE The cell wall is a critical structural component of bacterial cells that confers important physiological functions. For pathogens, it is a site of host-pathogen interactions. In this work, we analyze the glycolipids synthesized by the mitis group streptococcal species, S. pneumoniae, S. oralis, and S. mitis. We find that all produce the glycolipid, glycerophosphate (Gro-P)-linked dihexosyl (DH)-diacylglycerol (DAG), which is a precursor for the cell wall polymer type I lipoteichoic acid in other bacteria. We investigate whether the known enzyme for type I LTA synthesis, LtaS, plays a role in synthesizing this molecule in S. mitis. Our results indicate that a novel mechanism is responsible. Our results are significant because they identify a novel feature of S. pneumoniae, S. oralis, and S. mitis glycolipid biology.

Microorganisms: A Potential Source of Bioactive Molecules for Antioxidant Applications

Oxidative stress originates from an elevated intracellular level of free oxygen radicals that cause lipid peroxidation, protein denaturation, DNA hydroxylation, and apoptosis, ultimately impairing cell viability. Antioxidants scavenge free radicals and reduce oxidative stress, which further helps to prevent cellular damage. Medicinal plants, fruits, and spices are the primary sources of antioxidants from time immemorial. In contrast to plants, microorganisms can be used as a source of antioxidants with the advantage of fast growth under controlled conditions. Further, microbe-based antioxidants are nontoxic, noncarcinogenic, and biodegradable as compared to synthetic antioxidants. The present review aims to summarize the current state of the research on the antioxidant activity of microorganisms including actinomycetes, bacteria, fungi, protozoa, microalgae, and yeast, which produce a variety of antioxidant compounds, i.e., carotenoids, polyphenols, vitamins, and sterol, etc. Special emphasis is given to the mechanisms and signaling pathways followed by antioxidants to scavenge Reactive Oxygen Species (ROS), especially for those antioxidant compounds that have been scarcely investigated so far.

In Vivo Evaluation of Immune-Enhancing Activity of Red Gamju Fermented by Probiotic Levilactobacillus brevis KU15154 in Mice

The purpose of this study was to evaluate the immune-enhancing effect of red gamju fermented with Levilactobacillus brevis KU15154, isolated from kimchi, as a biofunctional beverage using mice. Thirty-two mice were used, and after a 2-week feeding, the growth, cytokine and immunoglobulin production, and immune-related cell activation (phagocytes and natural killer [NK] cells) of the mice were evaluated. The red gamju- (SR) and fermented red gamju- (FSR) treated groups had 3.5-4.0-fold greater T-cell proliferation ability than the negative control group. IFN-γ production in the FSR group (15.5 ± 1.2 mg/mL) was significantly higher (p < 0.05) than that in the SR group (12.5 ± 1.8 mg/mL). The FSR group (502.6 ± 25.8 μg/mL) also showed higher IgG production levels than the SR group (412.2 ± 44.8 μg/mL). The activity of NK cells treated with FSR was also greater than that of cells treated with SR but it was not significant (p ≤ 0.05). Further, the phagocytic activity of peritoneal macrophages was higher in both SR and FSR groups than in the control group but was not significantly different (p < 0.05) between the SR and FSR groups. In conclusion, L. brevis KU15154 may be applied in the fermentation of bioactive food products, such as beverages or pharmaceutical industries, to potentially improve immunity.

Manganese superoxide dismutase induced by lipoteichoic acid isolated from Staphylococcus aureus regulates cytokine production in THP-1 cells

Lipoteichoic acid isolated from Staphylococcus aureus (aLTA) is known to regulate the production of pro-inflammatory cytokines through TLR2-mediated signaling pathways. In our previous study, we found that aLTA significantly increased manganese superoxide dismutase (MnSOD) in the THP-1 human monocyte-like cell line, but the role of MnSOD in the regulation of cytokine production was not elucidated. In the current study, we found that MnSOD was involved in aLTA-mediated cytokine production. The signaling pathways associated with aLTA-mediated MnSOD induction in THP-1 cells included TLR2-MyD88-IRAK2, JNK (c-Jun N-terminal kinases)1/2 and nuclear factor- κB (NF-κB). We also found MnSOD was involved in the regulation of IL-1β and TNF-α, which were induced by early signaling pathways, including JNK1/2, p38, and NF-κB p65. In addition, MnSOD was also involved in the production of IL-6 and CCL2 in aLTA-stimulated THP-1 cells through activation of late signaling pathways such as JAK2-STAT3. Taken together, our data suggest that aLTA-mediated MnSOD production involved in the regulation of cytokine production and it may be the cause of one of the excessive inflammatory reactions caused by S. aureus.

Lactobacillus sakei ADM14 Induces Anti-Obesity Effects and Changes in Gut Microbiome in High-Fat Diet-Induced Obese Mice

The aim of our study was to evaluate the anti-obesity effects of Lactobacillus sakei (L. sakei) ADM14 administration in a high-fat diet-induced obese mouse model and the resulting changes in the intestinal microbiota. Prior to in vivo testing, L. sakei ADM14 was shown to inhibit adipogenesis through in vitro test and genetic analysis. Subsequently, mice were orally administered 0.85% saline supplemented or not with L. sakei ADM14 to high-fat diet group and normal diet group daily. The results showed that administration of L. sakei ADM14 reduced weight gain, epididymal fat expansion, and total blood cholesterol and glucose levels, and significantly decreased expression of lipid-related genes in the epididymal fat pad. Administration of L. sakei ADM14 showed improvement in terms of energy harvesting while restoring the Firmicutes to Bacteroidetes ratio and also increased the relative abundance of specific microbial taxa such as Bacteroides faecichinchillae and Alistipes, which are abundant in non-obese people. L. sakei ADM14 affected the modulation of gut microbiota, altered the strain profile of short-chain fatty acid production in the cecum and enhanced the stimulation of butyrate production. Overall, L. sakei ADM14 showed potential as a therapeutic probiotic supplement for metabolic disorders, confirming the positive changes of in vivo indicators and controlling gut microbiota in a high-fat diet-induced obese mouse model.

Differential role of lipoteichoic acids isolated from Staphylococcus aureus and Lactobacillus plantarum on the aggravation and alleviation of atopic dermatitis

Lipoteichoic acid (LTA), a cell wall component of gram-positive bacteria, up-regulates inflammatory cytokine production through the toll-like receptor 2 (TLR2) signaling pathway, and also contributes to anti-inflammatory responses against immune cells stimulated by lipopolysaccharides. In the current study, we examined the effects of LTAs isolated from Staphylococcus aureus (aLTA) and Lactobacillus plantarum (pLTA) on the aggravation and alleviation of atopic dermatitis (AD). aLTA strongly induced CCL2 production in THP-1 cells. CCL2 was regulated by the TLR2 pathway including the activation of IRAK2, NF-κB and JNK. CCL2 induced Th2 polarization of CD4+T cells through induction of interleukin (IL)-2, -4, and -5 and inhibition of interferon-gamma (IFN-γ). CCL2 levels and immunoglobulin E (IgE) production were increased in aLTA-injected mice. On the other hand, pLTA moderately affected CCL2 production and it inhibited aLTA-mediated CCL2 production. The serum levels of CCL2 and IgE were inhibited by pLTA pre-injection followed by aLTA reinjection, which resulted in the alleviation of irritant contact dermatitis (ICD) symptoms. Our results suggest that S. aureus infection causes an increase in CCL2 production, and may exacerbate atopic dermatitis (AD)-like symptoms through the excessive IgE production. Alternatively, pLTA alleviated AD-like symptoms by inhibiting aLTA-induced CCL2 and IgE production.

Therapeutic effect of Lactobacillus rhamnosus SHA113 on intestinal infection by multi-drug-resistant Staphylococcus aureus and its underlying mechanisms

Staphylococcus aureus, especially multi-drug-resistant (MDR) pathogenic S. aureus, poses a severe threat to food safety and human health. Probiotics offer promising potential for the control of MDR pathogens because of their safe and biofunctional properties. This study shows that Lactobacillus rhamnosus SHA113, a strain isolated from the milk of healthy women, could efficiently inhibit MDR S. aureus both in vitro and in vivo. In vitro, L. rhamnosus efficiently inhibited and even killed drug resistant and drug sensitive S. aureus strains. In vivo experiments showed that SHA113 could efficiently decrease the number of S. aureus cells, inhibit the expression of inflammatory factors TNF-α and IL-6, and restore the level of white cells and neutrophils in the blood. SHA113 could also efficiently repair damage of the intestinal barrier and other functions impaired by S. aureus infection. This was indicated by a change of intestinal villi length and structure, and an up-regulated expression of tight junction proteins ZO-1 and occludin. SHA113 also restored the structural damage of immune organs, such as the enlargement of the spleen and the increased level of inflammatory cytokines caused by S. aureus infection. More importantly, L. rhamnosus SHA113 showed more effective inhibitory and therapeutic effects on MDR S. aureus strain ZBQ006 than on drug sensitive S. aureus strain 29213. These results illustrated that L. rhamnosus SHA113 has great potential for the treatment of MDR S. aureus contamination as food control and for therapeutic treatment.

Feeding lactobacilli impacts lupus progression in (NZBxNZW)F1 lupus-prone mice by enhancing immunoregulation

Although the relationship between autoimmunity and microorganisms is complex, there is evidence that microorganisms can prevent the development of various autoimmune diseases. Lactobacilli are beneficial gut bacteria that play an important role in immune system development. The goals of this study were to assess the ability of three different strains of lactobacilli (L. casei B255, L. reuteri DSM 17509 and L. plantarum LP299v) to control lupus development/progression in (NZBxNZW)F1 (BWF1) lupus-prone mice before and after disease onset, and identify the mechanisms mediating protection. BWF1 mice fed with individual L. casei or L. reuteri before disease onset exhibited delayed lupus onset and increased survival, while feeding L. plantarum had little impact. In vitro treatment of BWF1 dendritic cells with individual lactobacilli strains upregulated IL-10 production to various extents, with L. casei being the most effective. The protection mediated by L. casei was associated with upregulation of B7-1 and B7-2 by antigen presenting cells, two costimulatory molecules important for regulatory T cell (Treg) induction. Moreover, feeding L. casei lead to increased percentages of CD4⁺Foxp3⁺ Tregs and IL10-producing T cells in the lymphoid organs of treated mice. More importantly, mice fed L. casei after disease onset remained stable for several months, i.e. exhibited delayed anti-nucleic acid production and kidney disease progression, and increased survival. Therefore, feeding lactobacilli appears to delay lupus progression possibly via mechanisms involving Treg induction and IL-10 production. Altogether, these data support the notion that ingestion of lactobacilli, with immunoregulatory properties, may be a viable strategy for controlling disease development and progression in patients with lupus, i.e. extending remission length and reducing flare frequency.

Isolation, characterization and anti-inflammatory mechanism of probiotics in lipopolysaccharide-stimulated RAW 264.7 macrophages

Probiotics are known to modulate gut microbiota, intestinal barrier function and host immune response, but due to the species and strain specific response their mechanisms are not clearly understood. Thus, the present study was designed to isolate, assess the anti-inflammatory potential and underlying modulatory mechanisms of indigenous probiotics in murine macrophage cell line, RAW 264.7. Forty lactic acid bacteria (LAB) were isolated from different sources and monitored for their anti-inflammatory potential against lipopolysaccharide (LPS) induced inflammatory stress employing RAW 264.7 cells. Among these isolates, only four LAB isolates exhibited more than 90% nitric oxide inhibition and possessed the probiotic attributes. Further, these selected LAB isolates reduced the level of pro-inflammatory cytokines, TNF-α, IL-1β and IL-6, inhibited the phosphorylation of Mitogen Activated Protein Kinases (MAPKs) i.e. p38 MAPK, ERK1/2 and SAPK/JNK and expression of cyclooxygenase-2 (COX-2) in LPS stimulated RAW 264.7 cells. The in vitro analysis suggested that the selected probiotic isolates attenuated the LPS-induced inflammation by downregulating MAPK pathway vis-a-vis inhibiting COX-2 and can be employed as anti-inflammatory agents in various inflammatory diseases.

Structural analysis of the lipoteichoic acid anchor glycolipid: Comparison of methods for degradation of the glycerophosphate backbone polymer

Acetic acid treatment [98% (v/v), 100 °C, 3 h] was proposed as a new method for degrading the glycerophosphate polymer moiety of Gram-positive bacterial lipoteichoic acid. We demonstrated that this method resulted in partial O-acetylation on the carbohydrate residues of the anchor glycolipid. Hence, the acetic acid treatment is not suitable for the chemical structural analysis of lipoteichoic acid.

Inflammatory Response to Different Toxins in Experimental Sepsis Models

Sepsis is defined as life-threatening organ dysfunction caused by the dysregulated host response to infection. Despite serious mortality and morbidity, no sepsis-specific drugs exist. Endotoxemia is often used to model the hyperinflammation associated with early sepsis. This model classically uses lipopolysaccharide (LPS) from Gram-negative pathogens to activate the immune system, leading to hyperinflammation, microcirculatory disturbances and death. Other toxins may also be used to activate the immune system including Gram-positive peptidoglycan (PG) and lipoteichoic acid (LTA). In addition to these standard toxins, other bacterial components can induce inflammation. These molecules activate different signaling pathways and produce different physiological responses which can be taken advantage of for sepsis modeling. Endotoxemia modeling can provide information on pathways to inflammation in sepsis and contribute to preclinical drug development.

Postbiotics: facts and open questions. A position paper on the need for a consensus definition

The past definitions of probiotics and prebiotics have been reviewed and updated recently. According to these concepts, probiotics comprise live microorganisms that confer a health benefit on the host when administered in adequate amounts, whereas a prebiotic is a substrate that is selectively utilised by host microorganisms, conferring a health benefit. The words probiotics and prebiotics can be found on labels of many foods and supplements. Consumers have a growing awareness of these terms' meanings, and many countries are increasingly using them for regulation purposes. At the same time, there is increasing evidence on the health effects of non-viable microorganisms and the metabolites that they can produce by fermentation or by their action on food components. Different terms have been used in the literature to refer to these bioactive compounds, which do not fall under the known categories of probiotics, prebiotics or synbiotics. The tentative term postbiotics has been the most used one so far. However, no definition of the term has gained international consensus to date. This work aims to provide information on the facts and the open questions about the so-called postbiotics.

The effects of the Lactobacillus acidophilus ATCC 4356 on the oxidative stress of reproductive system in diabetic male rats

BACKGROUND

Background: Oxidative stress plays an important role in the development of diabetic complications.

OBJECTIVE

This study evaluated the impact of pre- and post-treatment with Lactobacillus acidophilus ATCC 4356 on the oxidant and anti-oxidant factors of testis and epididymis in streptozotocin-induced diabetic rats.

MATERIALS AND METHODS

Thirty male Wistar rats (10 wk old) weighing 220-230 g. were divided into five groups (n = 6/ each): 1- normal group, 2- normal lactobacillus group, 3- diabetic group, 4- diabetic + lactobacillus before (DLB) group, and 5- diabetic + lactobacillus after (DLA) group. The normal and diabetic groups received daily 1 mL normal saline for 6 wk. Normal lactobacillus group received daily L. acidophilus for 6 wk. Group DLB received daily L. acidophilus for 2 wk before diabetes and for 4 wk after diabetes. Group DLA received daily 1 mL normal saline for 2 wk before diabetes and L. acidophilus for 4 wk after diabetes. The dose of L. acidophilus was 1 × 109 CFU/mL.

RESULTS

The administration of L. acidophilus worsened blood glucose level and reduced the levels of Malondialdehyde (p ≤ 0.0001) and Hydrogen peroxide (p ≤ 0.0001) and, Catalase and Glutathione peroxidase activity increased in the testis. In epididymis, Glutathione peroxidase and Catalase (p = 0.013) activity increased and Hydrogen peroxide concentration reduced, while Malondialdehyde concentration did not show any changes compared to the diabetic rats. Also, there was no significant difference between DLB and DLA groups, in these markers.

CONCLUSION

Data obtained suggests that L. acidophilus has anti-oxidant effects on the testis and sometime in the epididymis in diabetic rats.

In Vitro Immune-Enhancing Activity of Ovotransferrin from Egg White via MAPK Signaling Pathways in RAW 264.7 Macrophages

Ovotransferrin (OTF) is a well-known protein of the transferrin family with strong iron chelating activity, resulting in its antimicrobial activity. Furthermore, OTF is known to have antioxidant, anticancer, and antihypertensive activities. However, there have been few studies about the immune-enhancing activity of OTF. In current study, we investigated the immune-enhancing activity of OTF using the murine macrophage cells in vitro. The effect of OTF on production of pro-inflammatory mediators and cytokines were determined using Griess assay and quantitative real-time PCR. Using Neutral Red uptake assay, we confirmed the effect of OTF on phagocytic activity of macrophages. Ovotransferrin significantly increased the production of nitric oxide (NO) and secretion of inducible nitric oxide synthase (iNOS) mRNA with no cytotoxic activity. Ovotransferrin (2 mg/mL) stimulated NO production up to 31.9±3.5 μM. Ovotransferrin significantly increased the mRNA expression levels of pro-inflammatory cytokines which are tumor necrosis factor-α (TNF-α), Interleukin-1β (IL-1β), and IL-6: OTF (2 mg/mL) treatment increased the secretion of mRNA for TNF-α, IL-1β, and IL-6 by 22.20-, 37.91-, and 6.17-fold of the negative control, respectively. The phagocytic activity of macrophages was also increased by OTF treatment significantly compared with negative control. Also, OTF treatment increased phosphorylation level of MAPK signaling pathways. These results indicated that OTF has immune-enhancing activity by activating RAW 264.7 macrophages via MAPK pathways.

Antioxidant and immune-enhancing effects of probiotic Lactobacillus plantarum 200655 isolated from kimchi

Probiotic properties including antioxidant and immune-enhancing effects of Lactobacillus plantarum 200655 isolated from kimchi were evaluated. The tolerance of three strains (L. plantarum 200655, L. plantarum KCTC 3108, and L. rhamnosus GG to bile salts (0.3% oxgall, 24 h) was similar, and L. plantarum 200655 showed the highest tolerance to gastric juice (0.3% pepsin, 3 h). All strains presented similar autoaggregation ability. L. plantarum 200655 showed higher cell surface hydrophobicity and adhesion ability on HT-29 cells. L. plantarum 200655 did not produce β-glucuronidase and was sensitive to ampicillin, tetracycline, chloramphenicol, and doxycycline. Additionally, L. plantarum 200655 showed the highest antioxidant effects in DPPH and ABTS radical scavenging, and β-carotene bleaching assays. RAW 264.7 cells treated with L. plantarum 200655 produced more nitric oxide, induced nitric oxide synthase, and cytokine related to immune-enhancing effects such as interleukin-1β and interleukin-6. Therefore, L. plantarum 200655 could be useful as a probiotic strain for older people.

Mixed Lactobacillus plantarum Strains Inhibit Staphylococcus aureus Induced Inflammation and Ameliorate Intestinal Microflora in Mice

Objective. Staphylococcus aureus is an important pathogen that causes intestinal infection. We examined the immunomodulatory function of single and mixed Lactobacillus plantarum strains, as well as their impacts on the structure of the microbiome in mice infected with Staphylococcus aureus. The experiment was divided into three groups: protection, treatment, and control. Serum IFN-γ and IL-4 levels, as well as intestinal sIgA levels, were measured during and 1 week after infection with Staphylococcus aureus with and without Lactobacillus plantarum treatment. We used 16s rRNA tagged sequencing to analyze microbiome composition. IFN-γ/IL-4 ratio decreased significantly from infection to convalescence, especially in the mixed Lactobacillus plantarum group. In the mixed Lactobacillus plantarum group the secretion of sIgA in the intestine of mice (9.4-9.7 ug/mL) was significantly higher than in the single lactic acid bacteria group. The dominant phyla in mice are Firmicutes, Bacteroidetes, and Proteobacteria. Treatment with mixed lactic acid bacteria increased the anti-inflammatory factor and the secretion of sIgA in the intestine of mice infected with Staphylococcus aureus and inhibited inflammation.

Protective effects and functional mechanisms of Lactobacillus gasseri SBT2055 against oxidative stress

Lactobacillus gasseri SBT2055 (LG2055) is one of the probiotic lactic acid bacteria. Recently, we demonstrated that feeding with LG2055 extended the lifespan of Caenorhabditis elegans and that the prolongevity effect was dependent upon the regulation of oxidative stress response. In this study, we assessed whether LG2055 regulated the oxidative stress response of mammalian cells. In NIH-3T3 cells and primary mouse embryonic fibroblast cells, low cell proliferation rates and high reactive oxygen species levels were observed following paraquat treatment. LG2055 treatment suppressed these responses in paraquat-treated cells, indicating that LG2055 protected against oxidative stress in mammalian cells. The mRNA expression of oxidative stress-related genes, total nuclear factor-erythroid-2-related factor 2 (Nrf2) protein levels, and the nuclear translocation of Nrf2 were increased by LG2055 treatment. These results suggested that the Nrf2-antioxidant response element (ARE) signaling pathway was activated by LG2055. Furthermore, c-Jun NH₂-terminal kinase (JNK) was activated by LG2055 treatment and the inhibition of JNK suppressed the activation of the Nrf2-ARE signaling pathway in LG2055-treated cells. Together, these findings suggest that LG2055 activated the Nrf2-ARE signaling pathway by JNK activation, thus strengthening the defense system against oxidative stress in mammalian cells.

Lactobacillus delbrueckii subsp. lactis (strain CIDCA 133) stimulates murine macrophages infected with Citrobacter rodentium

Citrobacter rodentium is a specific murine enteropathogen which causes diarrheal disease characterized by colonic hyperplasia and intestinal inflammation. Recruitment of neutrophils and macrophages constitute a key step to control the infection. Since modulation of the activity of professional phagocytic cells could contribute to improve host´s defences against C. rodentium, we investigated the effect of Lactobacillus delbrueckii subsp. lactis (strain CIDCA 133) on the interaction between murine macrophages (RAW 264.7) and C. rodentium. Phagocytosis, surface molecules and inducible nitric oxide synthase (iNOs) expression were determined by flow cytometry. Reactive oxygen species (ROS) were assessed by fluorescence microscopy. The presence of lactobacilli increased phagocytosis of C. rodentium whereas C. rodentium had no effect on lactobacilli internalization. Survival of internalized C. rodentium diminished when strain CIDCA 133 was present. CD-86, MHCII, iNOs expression and nitrite production were increased when C. rodentium and lactobacilli were present even though strain CIDCA 133 alone had no effect. Strain CIDCA 133 led to a strong induction of ROS activity which was not modified by C. rodentium. Lactobacillus delbrueckii subsp. lactis (strain CIDCA 133) is able to increase the activation of murine macrophages infected with C. rodentium. The sole presence of lactobacilli is enough to modify some stimulation markers (e.g. ROS induction) whereas other markers require the presence of both bacteria; thus, indicating a synergistic effect.

Capacity of lactic acid bacteria in immunity enhancement and cancer prevention

Lactic acid bacteria are associated with the human gastrointestinal tract. They are important for maintaining the balance of microflora in the human gut. An increasing number of published research reports in recent years have denoted the importance of producing interferon-gamma and IgA for treatment of disease. These agents can enhance the specific and nonspecific immune systems that are dependent on specific bacterial strains. The mechanisms of these effects were revealed in this investigation, where the cell walls of these bacteria were modulated by the cytokine pathways, while the whole bacterial cell mediated the host cell immune system and regulated the production of tumor necrosis factors and interleukins. A supplement of highly active lactic acid bacteria strains provided significant potential to enhance host's immunity, offering prevention from many diseases including some cancers. This review summarizes the current understanding of the function of lactic acid bacteria immunity enhancement and cancer prevention.

Structural diversity and biological significance of lipoteichoic acid in Gram-positive bacteria: focusing on beneficial probiotic lactic acid bacteria

Bacterial cell surface molecules are at the forefront of host-bacterium interactions. Teichoic acids are observed only in Gram-positive bacteria, and they are one of the main cell surface components. Teichoic acids play important physiological roles and contribute to the bacterial interaction with their host. In particular, lipoteichoic acid (LTA) anchored to the cell membrane has attracted attention as a host immunomodulator. Chemical and biological characteristics of LTA from various bacteria have been described. However, most of the information concerns pathogenic bacteria, and information on beneficial bacteria, including probiotic lactic acid bacteria, is insufficient. LTA is structurally diverse. Strain-level structural diversity of LTA is suggested to underpin its immunomodulatory activities. Thus, the structural information on LTA in probiotics, in particular strain-associated diversity, is important for understanding its beneficial roles associated with the modulation of immune response. Continued accumulation of structural information is necessary to elucidate the detailed physiological roles and significance of LTA. In this review article, we summarize the current state of knowledge on LTA structure, in particular the structure of LTA from lactic acid bacteria. We also describe the significance of structural diversity and biological roles of LTA.

In vitro and in vivo downregulation of C3 by lipoteichoic acid isolated from Lactobacillus plantarum K8 suppressed cytokine-mediated complement system activation

Complement component 3 (C3) is one of the proteins associated with complement cascades. C3 plays an essential role in three different pathways-the alternative, classical and lectin pathways. It is well known that cytokines activate complement system and increase complement component C3 production. In the current study, we found that lipoteichoic acid isolated from Lactobacillus plantarum K8 (pLTA) inhibited tumor necrosis factor-alpha (TNF-α) or interferon-gamma (IFN-γ)-mediated C3 mRNA and protein expression in HaCaT cells. pLTA inhibited C3 expression through the inhibition of the phosphorylation of p65 and p38 in the TNF-α-treated cells, while the inhibition of STAT1/2 and JAK2 phosphorylation by pLTA contributed to the reduction of C3 in IFN-γ-treated cells. When mice were pre-injected with pLTA followed by re-injection of TNF-α, serum C3 level was decreased as compared to TNF-α-injected only. Further studies revealed that membrane attack complex (MAC) increased by TNF-α injection was lessened in pLTA-pre-injected mice. A bactericidal assay using mouse sera showed that MAC activity in pLTA-pre-injected mice was lower than in TNF-α only-injected mice. These results suggest that pLTA can suppress inflammatory cytokine-mediated complement activation through the inhibition of C3 synthesis. pLTA application has the potential to alleviate complement-mediated diseases caused by excessive inflammation.

Lactobacillus acidophilus K301 Inhibits Atherogenesis via Induction of 24 (S), 25-Epoxycholesterol-Mediated ABCA1 and ABCG1 Production and Cholesterol Efflux in Macrophages

Lactobacillus acidophilus species are well-known probiotics with the beneficial activity of regulating cholesterol levels. In this study, we showed that L. acidophilus K301 reduced the level of cholesterol through reverse transport in macrophages. L. acidophilus K301 upregulated the mRNA and protein levels of genes such as ATP-binding cassette A1 (ABCA1) and ATP-binding cassette G1 (ABCG1) under the control of liver X receptor (LXR), resulting in increased apoA-I-dependent cholesterol efflux in phorbol 12-myristate 13-acetate (PMA)-differentiated THP-1 cells. L. acidophilus K301 induced both ABCA1 and ABCG1 through the endogenous LXR agonist 24(S), 25-epoxcycholesterol, which is synthesized by intracellular cholesterol synthetic pathways. In vivo studies using L. acidophilus K301-treated ApoE^-/- mice showed reduced accumulation of lipoproteins in the arterial lumen. The inhibitory effects of L. acidophilus K301 on accumulation of lipoprotein in atherosclerotic plaques were mediated by the induction of squalene reductase (SQLE) and oxidosqualene cyclase (OSC) and resulted in ABCA1-mediated cholesterol efflux. Taken together, our findings revealed that Lactobacillus acidophilus K301 regulates the expression of genes related to cholesterol reverse transport via the induction of endogenous LXR agonist, suggesting the therapeutic potential of Lactobacillus acidophilus K301 as an anti-atherosclerotic agent.

Characterization, Anti-Inflammatory and Antiproliferative Activities of Natural and Sulfonated Exo-Polysaccharides from Streptococcus thermophilus ASCC 1275

Exo-polysaccharides (EPS) isolated from Streptococcus thermophilus ASCC 1275 were sulfated (31%). High-performance liquid chromatography identified that EPS was composed of mannose (30.19%), galactose (20.10%), glucose (18.05%), glucosamine (16.04%), galactosamine (9.06%), glucuronic acid (3.55%), and ribose (3.01%). Pro-/anti-inflammatory cytokine secretion ratios (IL-1β/IL-10, IL-6/IL-10, and TNF-α/IL-10) of lipopolysaccharide stimulated RAW 264.7 macrophages were significantly decreased by EPS and S.EPS treatments in a dose dependent manner. Furthermore, anti-inflammatory activities of S.EPS improved 49.3% and 24.0% than those of EPS before or after LPS treatment. The reactive oxygen species were inhibited by EPS and S.EPS by 49.6% and 55.1% at 50 μg/mL, respectively. Inhibition activities of S.EPS on nitric oxide production were 12.9% and 55.4% higher than those of EPS at 10 and 50 μg/mL. Additionally, S.EPS exhibited stronger antiproliferative activity on Caco-2 and HepG2 cells. Our results indicated that anti-inflammatory and antiproliferative activities of EPS were significantly (P < 0.01) improved by sulfonation.

Lipoteichoic acid isolated from Lactobacillus plantarum down-regulates UV-induced MMP-1 expression and up-regulates type I procollagen through the inhibition of reactive oxygen species generation

BACKGROUND

Ultraviolet (UV) irradiation from the sun is the primary environmental factor that causes human skin aging. UV irradiation induces the expressions of matrix metalloproteinases (MMPs) and extracellular matrix degrading enzymes. Among the members of MMP family, MMP-1 is an interstitial collagenase that degrades the collagen triple helix. We investigated the effect of Lactobacillus plantarum, well known as useful microorganism, on UV-induced-MMP-1 expression in human dermal fibroblasts.

METHODS

Human dermal fibroblasts (HDF) was pre-stimulated with lipoteichoic acid isolated from L. plantarum followed by UV irradiation. Secreted protein level of MMP-1 was evaluated by Western blot analysis. The phosphorylation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) from the cell lysates was also examined by western blotting. Electrophoretic mobility-shift assay (EMSA) was used to detect the activated transcription factor, AP-1 and NF-κB. The detection of type 1 procollagen was carried with Procollagen type 1 C-peptide (PIP) EIA kit. The generation of reactive oxygen species (ROS) by LTA and UV irradiation was examined by Griess reagent assay and fluorescence microscope.

RESULTS

We found that lipoteichoic acid (LTA), a cell-wall component of Gram-positive bacteria, isolated from L. plantarum, inhibited MMP-1 expression. Pretreatment with LTA from L. plantarum (pLTA) reduced MMP-1 expression in a dose-dependent manner and inhibited activation of extracellular signal-regulated kinases (ERK) and c-Jun N-terminal kinases (JNK). It also led to the inhibition of DNA binding activity of activator protein-1 (AP-1) and of nuclear factor kappa-light-chain-enhancer of activated B cell (NF-κB). Furthermore, LTA promoted type 1 procollagen synthesis and reduced the generation of ROS induced by UV irradiation.

CONCLUSION

Our study demonstrates that pLTA inhibits degradation of collagen and promotes its synthesis and that pLTA contributes to a decrease in ROS production. Therefore, pLTA from L. plantarum has potential abilities to prevent and treat skin photo-aging.