Lipoprotein Lipase and Hydrofluoric Acid Deactivate Both Bacterial Lipoproteins and Lipoteichoic Acids, but Platelet-Activating Factor-Acetylhydrolase Degrades Only Lipoteichoic Acids

Seo, Ho Seong; Nahm, Moon H.

doi:10.1128/cvi.00115-09

Cited by 16 publications

(23 citation statements)

References 63 publications

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“…The strong inflammatory response to invasive GAS infection may result in severe disease symptoms, such as toxic shock. In this work, we demonstrated that lactic acid degrades LTA, which causes damage to epithelial cells and is very potent in inducing inflammation through induction of TNF (13,43). Degradation of LTA might be an important mechanism by which lactobacilli protect against severe inflammation.…”

Section: Vol 55 2011 Degradation Of Lta By Lactobacilli 1625mentioning

confidence: 85%

Lactobacilli Reduce Cell Cytotoxicity Caused by Streptococcus pyogenes by Producing Lactic Acid That Degrades the Toxic Component Lipoteichoic Acid

Maudsdotter

Jonsson

Roos

et al. 2011

Antimicrob Agents Chemother

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Lactobacilli are known to prevent colonization by many pathogens; nevertheless, the mechanisms of their protective effect are largely unknown. In this work, we investigated the role of lactobacilli during infection of epithelial cells with group A streptococci (GAS). GAS cause a variety of illnesses ranging from noninvasive disease to more severe invasive infections, such as necrotizing fasciitis and toxic shock-like syndrome. Invasion of deeper tissues is facilitated by GAS-induced apoptosis and cell death. We found that lactobacilli inhibit GAS-induced host cell cytotoxicity and shedding of the complement regulator CD46. Further, survival assays demonstrated that lactic acid secreted by lactobacilli is highly bactericidal toward GAS. In addition, lactic acid treatment of GAS, but not heat killing, prior to infection abolishes the cytotoxic effects against human cells. Since lipoteichoic acid (LTA) of GAS is heat resistant and cytotoxic, we explored the effects of lactic acid on LTA. By applying such an approach, we demonstrate that lactic acid reduces epithelial cell damage caused by GAS by degrading both secreted and cell-bound LTA. Taken together, our experiments reveal a mechanism by which lactobacilli prevent pathogen-induced host cell damage.Streptococcus pyogenes (group A streptococci [GAS]) is the cause of many important human diseases ranging from mild superficial skin infections to life-threatening systemic diseases. The pathogen is a common colonizer of the mucosal layers in the mouth, nose, and pharynx. Colonization by GAS is often transient and asymptomatic; however, dissemination by local infection occasionally develops into severe systemic disease, such as streptococcal toxic shock syndrome (8, 24). A pathogenicity feature of GAS is the ability to induce cytotoxicity in human cells (33, 37), which facilitates bacterial entry into deeper tissues of the body (2, 9). Invasion of host cells (17,26,53), as well as many virulence factors of GAS, such as the surface component lipoteichoic acid (LTA) (12, 19-22, 49, 51) and the toxins streptolysin O and streptolysin S (11,29,45), is reported to induce host cell damage. In addition, pathogeninduced apoptosis and necrosis lead to shedding of the cell surface complement regulator CD46 (14, 25). Shed CD46 binds to the surface of GAS and increases survival of the bacteria in the blood (23, 27).The normal microbiota is an important first line of defense against invading pathogens. The Gram-positive lactobacilli colonize various parts of the body and are common inhabitants of the mucosal membranes in the oral tract (1, 3, 39). Lactobacilli are known to protect against colonization by many pathogens (44) and have also been reported to prevent cytotoxicity induced by bacterial pathogens (4,5,15,31). In addition, in a recent study, Lactobacillus rhamnosus GG, a commonly used probiotic strain, was reported to inhibit GAS invasion of host cells (36). Lactobacilli have further been reported to inhibit streptococcal growth (15,18,46,47). However, the mechanisms of t...

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Section: Vol 55 2011 Degradation Of Lta By Lactobacilli 1625mentioning

confidence: 85%

Lactobacilli Reduce Cell Cytotoxicity Caused by Streptococcus pyogenes by Producing Lactic Acid That Degrades the Toxic Component Lipoteichoic Acid

Maudsdotter

Jonsson

Roos

et al. 2011

Antimicrob Agents Chemother

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“…The possible contamination of staphylococcal LTA preparations with lipoproteins has fuelled controversies as to the real activity of LTA (22). This is why we subjected the LTA preparation to enzymatic treatment with PAF-AH, as this enzyme was shown previously to inactivate LTA but not lipopeptides (58). The almost complete loss of CXCL8-stimulating activity after treatment with PAF-AH indicates that the activity was indeed due to LTA and not to lipoproteins.…”

Section: Discussionmentioning

confidence: 98%

“…LTA activity resisted boiling at 95°C for 10 min and proteinase K but was inactivated by PAF-AH (Fig. 5b), suggesting that its activity was due to LTA and not to lipoproteins, which were shown to resist PAF-AH (58).…”

Section: Induction Of Leukocyte Recruitment In Milk By Mdp and Ltamentioning

confidence: 98%

Muramyl Dipeptide Synergizes with Staphylococcus aureus Lipoteichoic Acid To Recruit Neutrophils in the Mammary Gland and To Stimulate Mammary Epithelial Cells

Bougarn

Cunha

Harmache

et al. 2010

Clin Vaccine Immunol

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Staphylococcus aureus, a major pathogen for the mammary gland of dairy ruminants, elicits the recruitment of neutrophils into milk during mastitis, but the mechanisms are incompletely understood. We investigated the response of the bovine mammary gland to muramyl dipeptide (MDP), an elementary constituent of the bacterial peptidoglycan, alone or in combination with lipoteichoic acid (LTA), another staphylococcal microbial-associated molecular pattern (MAMP). MDP induced a prompt and marked influx of neutrophils in milk, and its combination with LTA elicited a more intense and prolonged influx than the responses to either stimulus alone. The concentrations of several chemoattractants for neutrophils (CXCL1, CXCL2, CXCL3, CXCL8, and C5a) increased in milk after challenge, and the highest increases followed challenge with the combination of MDP and LTA. MDP and LTA were also synergistic in inducing in vitro chemokine production by bovine mammary epithelial cells (bMEpC). Nucleotide-binding oligomerization domain 2 (NOD2), a major sensor of MDP, was expressed (mRNA) in bovine mammary tissue and by bMEpC in culture. The production of interleukin-8 (IL-8) following the stimulation of bMEpC by LTA and MDP was dependent on the activation of NF-B. LTA-induced IL-8 production did not depend on platelet-activating factor receptor (PAFR), as the PAFR antagonist WEB2086 was without effect. In contrast, bMEpC and mammary tissue are known to express Toll-like receptor 2 (TLR2) and to respond to TLR2 agonists. Although the levels of expression of the inflammatory cytokines tumor necrosis factor alpha (TNF-␣) and IL-1␤ were increased by LTA and MDP at the mRNA level, no protein could be detected in the bMEpC culture supernatant. The level of induction of IL-6 was low at both the mRNA and protein levels. These results indicate that MDP and LTA exert synergistic effects to induce neutrophilic inflammation in the mammary gland. These results also show that bMEpC could contribute to the inflammatory response by recognizing LTA and MDP and secreting chemokines but not proinflammatory cytokines. Overall, this study indicates that the TLR2 and NOD2 pathways could cooperate to trigger an innate immune response to S. aureus mastitis.

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“…Lipoteichoic acid (LTA) was prepared from S. mitis SF100 by organic solvent extraction and octyl-Sepharose chromatography, as previously described (43)(44)(45)(46). Purified LTA (1 g/ml), human fibrinogen (5 g/ml) (Hematologic Technologies), and recombinant fibrinogen ␣, ␤, and ␥ chains (0.5 M) in PBS were immobilized in 96-well microtiter dishes by overnight incubation at 4°C.…”

mentioning

confidence: 99%

“…The pellets were suspended in PBS and adjusted to a concentration of 10 6 CFU/ml. Purified fibrinogen and human platelets were immobilized in 96-well microtiter plates as described previously (46). The plates were then treated with 300 l of casein-based blocking solution at 37°C for 1 h and washed three times with PBS.…”

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confidence: 99%

Characterization of the Fibrinogen Binding Domain of Bacteriophage Lysin from Streptococcus mitis

Seo

Sullam

2011

Infect Immun

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The binding of bacteria to human platelets is a likely central mechanism in the pathogenesis of infective endocarditis. Platelet binding by Streptococcus mitis SF100 is mediated in part by a lysin encoded by the lysogenic bacteriophage SM1. In addition to its role in the phage life cycle, lysin mediates the binding of S. mitis to human platelets via its interaction with fibrinogen on the platelet surface. To better define the region of lysin mediating fibrinogen binding, we tested a series of purified lysin truncation variants for their abilities to bind this protein. These studies revealed that the fibrinogen binding domain of lysin is contained within the region spanned by amino acid residues 102 to 198 (lysin ). This region has no sequence homology to other known fibrinogen binding proteins. Lysin bound fibrinogen comparably to full-length lysin and with the same selectivity for the fibrinogen A␣ and B␤ chains. Lysin 102-198 also inhibited the binding in vitro of S. mitis to human fibrinogen and platelets. When assessed by platelet aggregometry, the disruption of the lysin gene in SF100 resulted in a significantly longer time to the onset of aggregation of human platelets than that of the parent strain. The preincubation of platelets with purified lysin 102-198 also delayed the onset of aggregation by SF100. These results indicate that the binding of lysin to fibrinogen is mediated by a specific domain of the phage protein and that this interaction is important for both platelet binding and aggregation by S. mitis.The binding of bacteria to human platelets is thought to be a central event in the pathogenesis of infective endocarditis (14, 61). For numerous endocarditis-associated pathogens, including Staphylococcus aureus, Streptococcus gordonii, and Streptococcus sanguinis, the ability to bind platelets in vitro has been linked to virulence, as measured with animal models of endocarditis (24,37,49,61). Among the viridans group streptococci, Streptococcus mitis is a leading cause of this disease in humans (19,22,33). Despite its increasing importance as a pathogen, relatively little is known about the virulence determinants of this organism, particularly with regard to its interaction with platelets or other host components.Our previous studies found that the lysin encoded by the lysogenic bacteriophage SM1 of S. mitis (lysin SM1 ) is expressed on the surface of the bacterium and that this phage protein mediates the binding of S. mitis to human platelets through its interaction with fibrinogen on the platelet surface (30,47). This appears to be a highly specific interaction, in which lysin binds the A␣ and B␤ chains of fibrinogen. Of note, a disruption of the gene encoding lysin (lys) results in both a significant reduction in platelet binding by streptococci in vitro and reduced virulence, indicating that the direct interaction of lysin with fibrinogen contributes to the pathogenesis of endocardial infection by S. mitis.With a view toward better defining the structural basis of lysin-fibrinogen binding and...

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Lipoprotein Lipase and Hydrofluoric Acid Deactivate Both Bacterial Lipoproteins and Lipoteichoic Acids, but Platelet-Activating Factor-Acetylhydrolase Degrades Only Lipoteichoic Acids

Cited by 16 publications

References 63 publications

Lactobacilli Reduce Cell Cytotoxicity Caused by Streptococcus pyogenes by Producing Lactic Acid That Degrades the Toxic Component Lipoteichoic Acid

Lactobacilli Reduce Cell Cytotoxicity Caused by Streptococcus pyogenes by Producing Lactic Acid That Degrades the Toxic Component Lipoteichoic Acid

Muramyl Dipeptide Synergizes with Staphylococcus aureus Lipoteichoic Acid To Recruit Neutrophils in the Mammary Gland and To Stimulate Mammary Epithelial Cells

Characterization of the Fibrinogen Binding Domain of Bacteriophage Lysin from Streptococcus mitis

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