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Michael Otto - One of the best experts on this subject based on the ideXlab platform.
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toll like receptor 2 activation depends on lipopeptide shedding by bacterial surfactants
Nature Communications, 2016Co-Authors: Dennis Hanzelmann, Michael Otto, Dorothee Kretschmer, Mirita Franzwachtel, Tobias Hertlein, Stefan Stevanovic, Boris Macek, Christiane Wolz, Friedrich Gotz, Andreas PeschelAbstract:Sepsis caused by Gram-positive bacterial pathogens is a major fatal disease but its molecular basis remains elusive. Toll-like receptor 2 (TLR2) has been implicated in the orchestration of inflammation and sepsis but its role appears to vary for different pathogen species and clones. Accordingly, Staphylococcus aureus clinical isolates differ substantially in their capacity to activate TLR2. Here we show that strong TLR2 stimulation depends on high-level production of Phenol-Soluble Modulin (PSM) peptides in response to the global virulence activator Agr. PSMs are required for mobilizing lipoproteins, the TLR2 agonists, from the staphylococcal cytoplasmic membrane. Notably, the course of sepsis caused by PSM-deficient S. aureus is similar in wild-type and TLR2-deficient mice, but TLR2 is required for protection of mice against PSM-producing S. aureus. Thus, a crucial role of TLR2 depends on agonist release by bacterial surfactants. Modulation of this process may lead to new therapeutic strategies against Gram-positive infections. The role played by human protein TLR2 in inflammation and sepsis varies for different bacterial pathogens. Here, Hanzelmann et al. show that the differential abilities of Staphylococcus aureusstrains to activate TLR2 depend on their production of peptides that release lipoproteins known to act as TLR2 agonists.
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Mechanism of Gene Regulation by a Staphylococcus aureus Toxin
American Society for Microbiology, 2016Co-Authors: Hwang-soo Joo, Amer E. Villaruz, Daniel E. Sturdevant, Som S. Chatterjee, Seth W. Dickey, Vee Y. Tan, Yan Chen, Stacy M. Ricklefs, Michael OttoAbstract:The virulence of many bacterial pathogens, including the important human pathogen Staphylococcus aureus, depends on the secretion of frequently large amounts of toxins. Toxin production involves the need for the bacteria to make physiological adjustments for energy conservation. While toxins are primarily targets of gene regulation, such changes may be accomplished by regulatory functions of the toxins themselves. However, mechanisms by which toxins regulate gene expression have remained poorly understood. We show here that the staphylococcal Phenol-Soluble Modulin (PSM) toxins have gene regulatory functions that, in particular, include inducing expression of their own transport system by direct interference with a GntR-type repressor protein. This capacity was most pronounced in PSMs with low cytolytic capacity, demonstrating functional specification among closely related members of that toxin family during evolution. Our study presents a molecular mechanism of gene regulation by a bacterial toxin that adapts bacterial physiology to enhanced toxin production
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PSM-Mec - A Virulence Determinant that Connects TranscriptionalRegulation, Virulence, and Antibiotic Resistance in Staphylococci
Frontiers Media S.A., 2016Co-Authors: Joshua Mccausland, Li Qin, Gordon Cheung, Michael OttoAbstract:PSM-mec is a secreted virulence factor that belongs to the Phenol-Soluble Modulin (PSM) family of amphipathic, alpha-helical peptide toxins produced by Staphylococcus species. All known PSMs are core genome-encoded with the exception of PSM-mec, whose gene is found in specific sub-types of SCCmec methicillin resistance mobile genetic elements present in methicillin-resistant Staphylococcus aureus and coagulase-negative staphylococci. In addition to the cytolytic translational product, PSM-mec, the psm-mec locus encodes a regulatory RNA. In S. aureus, the psm-mec locus influences cytolytic capacity, methicillin resistance, biofilm formation, cell spreading and the expression of other virulence factors, such as other PSMs, which results in a significant impact on immune evasion and disease. However, these effects are highly strain-dependent, which is possibly due to differences in PSM-mec peptide versus psm-mec RNA-controlled effects. Here, we summarize the functional properties of PSM-mec and the psm-mec RNA molecule and their roles in staphylococcal pathogenesis and physiology
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role of phenol soluble Modulins in formation of staphylococcus aureus biofilms in synovial fluid
Infection and Immunity, 2015Co-Authors: Amer E. Villaruz, Som S. Chatterjee, Hwang-soo Joo, Gordon Y. C. Cheung, Vee Y. Tan, Sana Dastgheyb, Anthony C Duong, Noreen J Hickok, Michael OttoAbstract:ABSTRACT Staphylococcus aureus is a leading cause of prosthetic joint infections, which, as we recently showed, proceed with the involvement of biofilm-like clusters that cause recalcitrance to antibiotic treatment. Here we analyzed why these clusters grow extraordinarily large, reaching macroscopically visible extensions (>1 mm). We found that while specific S. aureus surface proteins are a prerequisite for agglomeration in synovial fluid, low activity of the Agr regulatory system and subsequent low production of the Phenol-Soluble Modulin (PSM) surfactant peptides cause agglomerates to grow to exceptional dimensions. Our results indicate that PSMs function by disrupting interactions of biofilm matrix molecules, such as the polysaccharide intercellular adhesin (PIA), with the bacterial cell surface. Together, our findings support a two-step model of staphylococcal prosthetic joint infection: As we previously reported, interaction of S. aureus surface proteins with host matrix proteins such as fibrin initiates agglomeration; our present results show that, thereafter, the bacterial agglomerates grow to extremely large sizes owing to the lack of PSM expression under the specific conditions present in joints. Our findings provide a mechanistic explanation for the reported extreme resistance of joint infection to antibiotic treatment, lend support to the notions that Agr functionality and PSM production play a major role in defining different forms of S. aureus infection, and have important implications for antistaphylococcal therapeutic strategies.
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Staphylococcus epidermidis Pathogenesis
Methods of Molecular Biology, 2013Co-Authors: Michael OttoAbstract:Abstract Staphylococcus epidermidis is the most frequently encountered member of the coagulase-negative staphylococci on human epithelial surfaces. It has emerged as an important nosocomial pathogen, especially in infections of indwelling medical devices. The mechanisms that S. epidermidis uses to survive during infection are in general of a passive nature, reflecting their possible origin in the commensal life of this bacterium. Most importantly, S. epidermidis excels in forming biofilms, sticky agglomerations that inhibit major host defense mechanisms. Furthermore, S. epidermidis produces a series of protective surface polymers and exoenzymes. Moreover, S. epidermidis has the capacity to secrete strongly cytolytic members of the Phenol-Soluble Modulin (PSM) family, but PSMs in S. epidermidis overall appear to participate primarily in biofilm development. Finally, there is evidence for a virulence gene reservoir function of S. epidermidis, as it appears to have transferred important immune evasion and antibiotic resistance factors to Staphylococcus aureus. Conversely, S. epidermidis also has a beneficial role in balancing the microflora on human epithelial surfaces by controlling outgrowth of harmful bacteria such as in particular S. aureus. Recent research yielded detailed insight into key S. epidermidis virulence determinants and their regulation, in particular as far as biofilm formation is concerned, but we still have a serious lack of understanding of the in vivo relevance of many pathogenesis mechanisms and the factors that govern the commensal life of S. epidermidis.
Seymour J Klebanoff - One of the best experts on this subject based on the ideXlab platform.
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An Inflammatory Polypeptide Complex from Staphylococcus epidermidis: Isolation and Characterization
2013Co-Authors: Christopher Mehlin, Catherine M. Headley, Seymour J KlebanoffAbstract:Staphylococcus epidermidis releases factors that activate the HIV-1 long terminal repeat, induce cytokine release, and activate nuclear factor �B in cells of macrophage lineage. The active material had a mass of 34,500 daltons, was inactivated by proteases and partitioned into the phenol layer on hot aqueous phenol extraction, and thus was termed Phenol-Soluble Modulin (PSM). High performance liquid chromatography (HPLC) of crude PSM yielded two peaks of activity designated PSM peak 1 and peak 2. MALDI-TOF (matrix-assisted laser desorption ionizationtime of flight) mass spectroscopy indicated the presence of two components in peak 1, which were designated PSM � and PSM�. Peak 2 contained a single component, designated PSM�. Separation of PSM � and PSM � in peak 1 could be achieved by a second HPLC procedure. The structure of each component was determined by amino acid sequence analysis and identification and sequencing of their genes. PSM�, PSM�, and PSM � were 22-, 44-, and 25-amino acid, respectively, strongly hydrophobic polypeptides. PSM � was identified as Staphylococcus epidermidis delta toxin, whereas PSM � and PSM � exhibited more distant homology to previously described staphylococcal toxins. They appeared to exist as a complex or aggregate with activity greater than the component parts. The properties of the S. epidermidis PSMs sugges
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activity of staphylococcus epidermidis phenol soluble Modulin peptides expressed in staphylococcus carnosus
The Journal of Infectious Diseases, 2004Co-Authors: Michael Otto, Shane D Omahoney, Tina Guina, Seymour J KlebanoffAbstract:: Staphylococcus epidermidis releases a group of peptides termed Phenol-Soluble Modulin (PSM) that stimulate macrophages. The structure of 3 peptides (PSM alpha, PSM beta, and PSM gamma ) have been described. We report a fourth peptide (PSM delta ), which is a 23mer with the structure fMSIVSTIIEVVKTIVDIVKKFKK. The gene for each of the 4 peptides was introduced singly into Staphylococcus carnosus, and the PSM-like activity of culture medium and bacterial extract were significantly greater than those of the parent strain. PSM peptides from each of the S. carnosus-expressing strains were purified and analyzed by liquid chromatography-mass spectrometry. The products, which appeared to form aggregates, were active in the activation of human immunodeficiency virus type 1 long-terminal repeat and the production of tumor necrosis factor- alpha by the macrophage cell line THP-1. These findings suggest that PSM peptides are responsible, in part, for the Modulin-like activity of staphylococci and may contribute to the development of severe staphylococcal sepsis.
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regulated expression of pathogen associated molecular pattern molecules in staphylococcus epidermidis quorum sensing determines pro inflammatory capacity and production of phenol soluble Modulins
Cellular Microbiology, 2004Co-Authors: Cuong Vuong, Seymour J Klebanoff, Andreas Peschel, Manuela Durr, Aaron B Carmody, Michael OttoAbstract:Summary Phenol-Soluble Modulin (PSM) is a peptide complex produced by the nosocomial pathogen Staphylococcus epidermidis that has a strong capacity to activate the human innate immune response. We developed a novel method based on liquid chromatography-mass spectrometry (LC-MS) to quantify the production of the individual PSM components. Each PSM peptide was abundant in most of the 76 S epidermidis strains tested. Importantly, none of the PSM components were secreted by an agr mutant strain, indicating that PSM synthesis is regulated strictly by the agr quorum-sensing system. Furthermore, the agr mutant strain failed to elicit production of TNFα by human myeloid cells and induced significantly less neutrophil chemotaxis compared with the wild-type strain. Thus, quorum-sensing in S. epidermidis dramatically influenced activation of human host defence. We propose that an agr quorum-sensing mechanism facilitates growth and survival in infected hosts by adapting production of the pro-inflammatory PSMs to the stage of infection.
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cutting edge functional interactions between toll like receptor tlr 2 and tlr1 or tlr6 in response to phenol soluble Modulin
Journal of Immunology, 2001Co-Authors: Adeline M Hajjar, Shane D Omahony, David M Underhill, Alan Aderem, Adrian Ozinsky, Seymour J Klebanoff, Chris WilsonAbstract:Toll-like receptor (TLR) 2 and TLR4 play important roles in the early, innate immune response to microbial challenge. TLR2 is preferentially involved in the inflammatory response to lipoteichoic acid, lipopeptides, and glycans from a variety of microbes, whereas TLR4 is essential for a complete response to LPSs. We report here that TLR2 transduces the response to Phenol-Soluble Modulin, a factor secreted by Staphylococcus epidermidis . The TLR2-mediated response to this Modulin was enhanced by TLR6 but inhibited by TLR1, indicating a functional interaction between these receptors. We also demonstrate that a response to Phenol-Soluble Modulin mediated by TLR2 and TLR6 was more refractory to inhibition by TLR1 than one mediated by TLR2 alone.
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an inflammatory polypeptide complex from staphylococcus epidermidis isolation and characterization
Journal of Experimental Medicine, 1999Co-Authors: Christopher Mehlin, Catherine M. Headley, Seymour J KlebanoffAbstract:Staphylococcus epidermidis releases factors that activate the HIV-1 long terminal repeat, induce cytokine release, and activate nuclear factor κB in cells of macrophage lineage. The active material had a mass of 34,500 daltons, was inactivated by proteases and partitioned into the phenol layer on hot aqueous phenol extraction, and thus was termed Phenol-Soluble Modulin (PSM). High performance liquid chromatography (HPLC) of crude PSM yielded two peaks of activity designated PSM peak 1 and peak 2. MALDI-TOF (matrix-assisted laser desorption ionization-time of flight) mass spectroscopy indicated the presence of two components in peak 1, which were designated PSMα and PSMβ. Peak 2 contained a single component, designated PSMγ. Separation of PSMα and PSMβ in peak 1 could be achieved by a second HPLC procedure. The structure of each component was determined by amino acid sequence analysis and identification and sequencing of their genes. PSMα, PSMβ, and PSMγ were 22-, 44-, and 25-amino acid, respectively, strongly hydrophobic polypeptides. PSMγ was identified as Staphylococcus epidermidis delta toxin, whereas PSMα and PSMβ exhibited more distant homology to previously described staphylococcal toxins. They appeared to exist as a complex or aggregate with activity greater than the component parts. The properties of the S . epidermidis PSMs suggest that they may contribute to the systemic manifestations of Gram-positive sepsis.
Gordon Y. C. Cheung - One of the best experts on this subject based on the ideXlab platform.
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Role of Phenol-Soluble Modulins in Formation of Staphylococcus aureus Biofilms in Synovial Fluid
2016Co-Authors: Gordon Y. C. Cheung, Noreen J Hickok, Hwang-soo A Joo, Michael B OttoaAbstract:Staphylococcus aureus is a leading cause of prosthetic joint infections, which, as we recently showed, proceed with the involve-ment of biofilm-like clusters that cause recalcitrance to antibiotic treatment. Here we analyzed why these clusters grow extraor-dinarily large, reaching macroscopically visible extensions (>1 mm). We found that while specific S. aureus surface proteins are a prerequisite for agglomeration in synovial fluid, low activity of the Agr regulatory system and subsequent low production of the Phenol-Soluble Modulin (PSM) surfactant peptides cause agglomerates to grow to exceptional dimensions. Our results indi-cate that PSMs function by disrupting interactions of biofilmmatrix molecules, such as the polysaccharide intercellular adhesin (PIA), with the bacterial cell surface. Together, our findings support a two-step model of staphylococcal prosthetic joint infec-tion: As we previously reported, interaction of S. aureus surface proteins with host matrix proteins such as fibrin initiates ag-glomeration; our present results show that, thereafter, the bacterial agglomerates grow to extremely large sizes owing to the lack of PSM expression under the specific conditions present in joints. Our findings provide a mechanistic explanation for the re-ported extreme resistance of joint infection to antibiotic treatment, lend support to the notions that Agr functionality and PSM production play a major role in defining different forms of S. aureus infection, and have important implications for antistaphy-lococcal therapeutic strategies. Staphylococcus aureus is a major cause of septic arthritis andorthopedic infections, in particular those developing on pros-thetic joints after arthroplasty (1). In the presence of a prostheti
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role of phenol soluble Modulins in formation of staphylococcus aureus biofilms in synovial fluid
Infection and Immunity, 2015Co-Authors: Amer E. Villaruz, Som S. Chatterjee, Hwang-soo Joo, Gordon Y. C. Cheung, Vee Y. Tan, Sana Dastgheyb, Anthony C Duong, Noreen J Hickok, Michael OttoAbstract:ABSTRACT Staphylococcus aureus is a leading cause of prosthetic joint infections, which, as we recently showed, proceed with the involvement of biofilm-like clusters that cause recalcitrance to antibiotic treatment. Here we analyzed why these clusters grow extraordinarily large, reaching macroscopically visible extensions (>1 mm). We found that while specific S. aureus surface proteins are a prerequisite for agglomeration in synovial fluid, low activity of the Agr regulatory system and subsequent low production of the Phenol-Soluble Modulin (PSM) surfactant peptides cause agglomerates to grow to exceptional dimensions. Our results indicate that PSMs function by disrupting interactions of biofilm matrix molecules, such as the polysaccharide intercellular adhesin (PIA), with the bacterial cell surface. Together, our findings support a two-step model of staphylococcal prosthetic joint infection: As we previously reported, interaction of S. aureus surface proteins with host matrix proteins such as fibrin initiates agglomeration; our present results show that, thereafter, the bacterial agglomerates grow to extremely large sizes owing to the lack of PSM expression under the specific conditions present in joints. Our findings provide a mechanistic explanation for the reported extreme resistance of joint infection to antibiotic treatment, lend support to the notions that Agr functionality and PSM production play a major role in defining different forms of S. aureus infection, and have important implications for antistaphylococcal therapeutic strategies.
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how staphylococcus aureus biofilms develop their characteristic structure
Proceedings of the National Academy of Sciences of the United States of America, 2012Co-Authors: Saravanan Periasamy, Som S. Chatterjee, Hwang-soo Joo, Gordon Y. C. Cheung, Vee Y. Tan, Anthony C Duong, Thanhhuy L Bach, Michael OttoAbstract:Biofilms cause significant problems in the environment and during the treatment of infections. However, the molecular mechanisms underlying biofilm formation are poorly understood. There is a particular lack of knowledge about biofilm maturation processes, such as biofilm structuring and detachment, which are deemed crucial for the maintenance of biofilm viability and the dissemination of cells from a biofilm. Here, we identify the Phenol-Soluble Modulin (PSM) surfactant peptides as key biofilm structuring factors in the premier biofilm-forming pathogen Staphylococcus aureus. We provide evidence that all known PSM classes participate in structuring and detachment processes. Specifically, absence of PSMs in isogenic S. aureus psm deletion mutants led to strongly impaired formation of biofilm channels, abolishment of the characteristic waves of biofilm detachment and regrowth, and loss of control of biofilm expansion. In contrast, induced expression of psm loci in preformed biofilms promoted those processes. Furthermore, PSMs facilitated dissemination from an infected catheter in a mouse model of biofilm-associated infection. Moreover, formation of the biofilm structure was linked to strongly variable, quorum sensing-controlled PSM expression in biofilm microenvironments, whereas overall PSM production remained constant to ascertain biofilm homeostasis. Our study describes a mechanism of biofilm structuring in molecular detail, and the general principle (i.e., quorum-sensing controlled expression of surfactants) seems to be conserved in several bacteria, despite the divergence of the respective biofilm-structuring surfactants. These findings provide a deeper understanding of biofilm development processes, which represents an important basis for strategies to interfere with biofilm formation in the environment and human disease.
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Interaction of Phenol-Soluble Modulins with Phosphatidylcholine Vesicles
MDPI AG, 2012Co-Authors: Anthony C Duong, Gordon Y. C. Cheung, Michael OttoAbstract:Several members of the staphylococcal Phenol-Soluble Modulin (PSM) peptide family exhibit pronounced capacities to lyse eukaryotic cells, such as neutrophils, monocytes, and erythrocytes. This is commonly assumed to be due to the amphipathic, α-helical structure of PSMs, giving PSMs detergent-like characteristics and allowing for a relatively non-specific destruction of biological membranes. However, the capacities of PSMs to lyse synthetic phospholipid vesicles have not been investigated. Here, we analyzed lysis of synthetic phosphatidylcholine (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, POPC) vesicles by all Staphylococcus aureus and S. epidermidis PSMs. In addition, we investigated the lytic capacities of culture filtrates obtained from different S. aureus PSM deletion mutants toward POPC vesicles. Our results show that all staphylococcal PSMs have phospholipid vesicle-lysing activity and the capacity of S. aureus culture filtrate to lyse POPC vesicles is exclusively dependent on PSMs. Notably, we observed largely differing capacities among PSM peptides to lyse POPC vesicles. Interestingly, POPC vesicle-lytic capacities did not correlate with those previously seen for the lysis of eukaryotic cells. For example, the β-type PSMs were strongly lytic for POPC vesicles, but are known to exhibit only very low lytic capacities toward neutrophils and erythrocytes. Thus our results also suggest that the interaction between PSMs and eukaryotic membranes is more specific than previously assumed, potentially depending on additional structural features of those membranes, such as phospholipid composition or yet unidentified docking molecules
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Distribution and Regulation of the Mobile Genetic Element-Encoded Phenol-Soluble Modulin PSM-mec in Methicillin-Resistant Staphylococcus aureus
2011Co-Authors: Som S. Chatterjee, Liang Chen, Hwang-soo Joo, Gordon Y. C. Cheung, Barry N. KreiswirthAbstract:The Phenol-Soluble Modulin PSM-mec is the only known staphylococcal toxin that is encoded on a mobile antibiotic resistance determinant, namely the staphylococcal cassette chromosome (SCC) element mec encoding resistance to methicillin. Here we show that the psm-mec gene is found frequently among methicillin-resistant Staphylococcus aureus (MRSA) strains of SCCmec types II, III, and VIII, and is a conserved part of the class A mec gene complex. Controlled expression of AgrA versus RNAIII in agr mutants of all 3 psm-mec-positive SCCmec types demonstrated that expression of psm-mec, which is highly variable, is controlled by AgrA in an RNAIII-independent manner. Furthermore, psm-mec isogenic deletion mutants showed only minor changes in PSMa peptide production and unchanged (or, as previously described, diminished) virulence compared to the corresponding wild-type strains in a mouse model of skin infection. This indicates that the recently reported regulatory impact of the psm-mec locus on MRSA virulence, which is opposite to that of the PSMmec peptide and likely mediated by a regulatory RNA, is minor when analyzed in the original strain background. Our stud
Yuri V. Kotlovsky - One of the best experts on this subject based on the ideXlab platform.
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healthcare and community associated methicillin resistant staphylococcus aureus mrsa and fatal pneumonia with pediatric deaths in krasnoyarsk siberian russia unique mrsa s multiple virulence factors genome and stepwise evolution
PLOS ONE, 2015Co-Authors: Olga Khokhlova, Wei-chun Hung, Tsai-wen Wan, Yasuhisa Iwao, Tomomi Takano, Wataru Higuchi, Svetlana V. Yachenko, Olga V. Teplyakova, Vera V. Kamshilova, Yuri V. KotlovskyAbstract:Methicillin-resistant Staphylococcus aureus (MRSA) is a common multidrug-resistant (MDR) pathogen. We herein discussed MRSA and its infections in Krasnoyarsk, Siberian Russia between 2007 and 2011. The incidence of MRSA in 3,662 subjects was 22.0% and 2.9% for healthcare- and community-associated MRSA (HA- and CA-MRSA), respectively. The 15-day mortality rates for MRSA hospital- and community-acquired pneumonia (HAP and CAP) were 6.5% and 50%, respectively. MRSA CAP cases included pediatric deaths; of the MRSA pneumonia episodes available, ≥27.3% were associated with bacteremia. Most cases of HA-MRSA examined exhibited ST239/spa3(t037)/SCCmecIII.1.1.2 (designated as ST239Kras), while all CA-MRSA cases examined were ST8/spa1(t008)/SCCmecIV.3.1.1(IVc) (designated as ST8Kras). ST239Kras and ST8Kras strongly expressed cytolytic peptide (Phenol-Soluble Modulin α, PSMα; and δ-hemolysin, Hld) genes, similar to CA-MRSA. ST239Kras pneumonia may have been attributed to a unique set of multiple virulence factors (MVFs): toxic shock syndrome toxin-1 (TSST-1), elevated PSMα/Hld expression, α-hemolysin, the staphylococcal enterotoxin SEK/SEQ, the immune evasion factor SCIN/SAK, and collagen adhesin. Regarding ST8Kras, SEA was included in MVFs, some of which were common to ST239Kras. The ST239Kras (strain OC3) genome contained: a completely unique phage, φSa7-like (W), with no att repetition; S. aureus pathogenicity island SaPI2R, the first TSST-1 gene-positive (tst+) SaPI in the ST239 lineage; and a super copy of IS256 (≥22 copies/genome). ST239Kras carried the Brazilian SCCmecIII.1.1.2 and United Kingdom-type tst. ST239Kras and ST8Kras were MDR, with the same levofloxacin resistance mutations; small, but transmissible chloramphenicol resistance plasmids spread widely enough to not be ignored. These results suggest that novel MDR and MVF+ HA- and CA-MRSA (ST239Kras and ST8Kras) emerged in Siberian Russia (Krasnoyarsk) associated with fatal pneumonia, and also with ST239Kras, a new (Siberian Russian) clade of the ST239 lineage, which was created through stepwise evolution during its potential transmission route of Brazil-Europe-Russia/Krasnoyarsk, thereby selective advantages from unique MVFs and the MDR.
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Genome information for the ST239Kras strain OC3, in comparison with the ST239 MRSA strain TW20.
2015Co-Authors: Olga E. Khokhlova, Wei-chun Hung, Tsai-wen Wan, Yasuhisa Iwao, Tomomi Takano, Wataru Higuchi, Svetlana V. Yachenko, Olga V. Teplyakova, Vera V. Kamshilova, Yuri V. KotlovskyAbstract:The ST239Kras OC3 genome contigs (including filled contigs and complete structures; total 2.91-Mb) were mapped on the 3,043,210-bp TW20 genome (GenBank accession number FN433596); in the figure, the two genome structures were drawn as two circles on a common genome map, outside OC3 and inside TW20. Genome information included staphylococcal cassette chromosome mec (SCCmec), other drug resistance structures (such as a transposon, Tn, plasmid-related structure, and gene mutations), characteristic virulence genes, phages, S. aureus pathogenicity islands (SaPIs), genomic islands (νSa), and characteristic insertion sequences (ISs). SCCmec: SCCmecIIIA (in OC3), SCCmecIII.1.1.2; SCCmecIII (in TW20), SCCmecIII.1.1.1 connected to SCCHg. Drug resistance (gene mutations): Lvxr, levofloxacin resistance; Rifr, rifampicin resistance; Sur, sulfamethoxazole resistance. Virulence genes (region): tst, toxic shock syndrome toxin-1 gene; hld, δ-hemolysin gene; cna, collagen adhesin gene; spa, protein A gene; psmα, Phenol-Soluble Modulin (PSM) gene; hla, α-hemolysin (α-toxin) gene; IEC, immune evasion cluster. The CC30 and CC8 genome sections are from Holden et al. [19], and the genetic element IEC6013 is from [60]. The plasmid pOC3 (2,908 bp; contig 75) of strain OC3 is not shown in the figure. The location of pSK41-related structure (with two IS431 repeats at both ends) currently remains uncertain.
Martine Deplanche - One of the best experts on this subject based on the ideXlab platform.
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Phenol-Soluble Modulins alpha induce G2/M phase transition delay and impair immune response of eukaryotic cells
2016Co-Authors: Martine Deplanche, Rachid El-aouar Filho, Julien Jardin, Gwenaele Henry, Vasco Azevedo, Ksenia Semenovskaya, Yves Le Loir, Liudmila Alekseeva, Pierre Germon, Pascal RainardAbstract:Staphylococcus aureus is responsible for a wide range of infections in human and animals. We found that S aureus slowed down host cell proliferation and induced a cytopathic effect. We demonstrated that S aureus induced a G2/M phase transition delay in host cells, which was associated with accumulation of the cyclin-dependent kinase Cdk1/cdc2 and unphosphorylated histone H3. We found that a G2 phase delay was preferential for bacterial internalization and intracellular proliferation. Using size exclusion chromatography and mass spectroscopy analysis, we identified Phenol-Soluble Modulin alpha (PSMα) peptides as the candidates for this effect. The implication of PSMα in cell cycle alteration was confirmed by testing of synthetic PSMα and by comparison of LACwt with the isogenic mutant LAC∆psm, which lacks the operon encoding PSMα. The delay was associated with a decrease of defensins expression in a G2 phase, suggesting that PSMα-induced G2/M phase transition delay deteriorates antibacterial state of the epithelial surface.Investigation of the response to Escherichia coli and S. aureus showed a higher expression of key cytokines IL-6, IL-8, as well as IL-32 (which is involved in dendritic cell maturation) in E. coli-infected host cells. Comparison of cytokines expression in response to LACwt with isogenic mutants, which lack the operon encoding PSMs, show that PSMs inhibit interleukins production, thus impair the innate and adaptive immune response during S. aureus infection. Therefore we show, that PSMs alter the host cell cycle, resulting in a reduction of defense response of host’ cells, that reveal a newly-identified mechanism for promoting infection.
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[i]Staphylococcus aureus[/i] Phenol-Soluble Modulins impair interleukin expression in bovine mammary epithelial cells.
2016Co-Authors: Martine Deplanche, Ksenia Semenovskaya, Frederic Dessauge, Laurence Finot, Wolfram Petzl, Holm Zerbe, Yves Le Loir, Pascal Rainard, Liudmila Alekseeva, David G.e. SmithAbstract:While the role of many cytokines during infection is revealed, the implication of several recently discovered cytokines during infection is not completely understood. The involvement of currently described interleukin-32 (IL-32) in infectious mastitis (an inflammation of the mammary gland), caused by two prevalent mastitis pathogens, Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) , was not investigated so far. We determined expression of IL-32, IL-6 and IL-8 in S. aureus- as compared to E.coli-infected bovine mammary gland epithelial cells. Using live bacteria we found that in S. aureus-infected cells, induction of IL-6 and IL-8 expression was less pronounced than in E. coli-infected cells. Notably, IL-32 expression was decreased in S. aureus-infected cells, while it was increased in E. coli-infected cells. IL-32 expression in E. coli- and S. aureus-infected udder tissue resembles in vitro responses. We identified the staphylococcal Phenol-Soluble Modulin (PSM) peptides as key contributors to these effects, as IL-32, IL-6 and IL-8 expression by epithelial cells exposed to psm mutant strains was significantly increased as compared to cells exposed to the isogenic S. aureus wild-type strain, indicating that PSMs inhibit the production of these interleukins. The use of genetically complemented strains confirmed this observation. Inasmuch as the decreased expression of IL-32, which is involved in dendritic cell maturation, impairs immune responses, our results support a PSM-dependent mechanism that allows for the development of chronic S aureus-related mastitis.
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Staphylococcus aureus Phenol-Soluble Modulins Impair Interleukin Expression in Bovine Mammary Epithelial Cells
Infection and Immunity, 2016Co-Authors: Martine Deplanche, Ludmila Alekseeva, Ksenia Semenovskaya, Frederic Dessauge, Laurence Finot, Wolfram Petzl, Holm Zerbe, Yves Le Loir, Pascal Rainard, David G.e. SmithAbstract:The role of the recently described interleukin-32 (IL-32) in Staphylococcus aureus-induced mastitis, an inflammation of the mammary gland, is unclear. We determined expression of IL-32, IL-6, and IL-8 in S. aureus- and Escherichia coli-infected bovine mammary gland epithelial cells. Using live bacteria, we found that in S. aureus-infected cells, induction of IL-6 and IL-8 expression was less pronounced than in E. coli-infected cells. Notably, IL-32 expression was decreased in S. aureus-infected cells, while it was increased in E. coli-infected cells. We identified the staphylococcal Phenol-Soluble Modulin (PSM) peptides as key contributors to these effects, as IL-32, IL-6, and IL-8 expression by epithelial cells exposed to psm mutant strains was significantly increased compared to that in cells exposed to the isogenic S. aureus wild-type strain, indicating that PSMs inhibit the production of these interleukins. The use of genetically complemented strains confirmed this observation. Inasmuch as the decreased expression of IL-32, which is involved in dendritic cell maturation, impairs immune responses, our results support a PSM-dependent mechanism that allows for the development of chronic S. aureus-related mastitis.
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Phenol soluble Modulin alpha alters the cell cycle of eukaryotic cells.
2015Co-Authors: Martine Deplanche, Rachid El-aouar Filho, Luidmila Alexseeva, Emilie Ladier, Julien Jardin, Gwenaele Henry, Vasco Azevedo, Frédéric Laurent, Gérard Lina, Francois VandeneschAbstract:Staphylococcus aureus (SA) is a Gram-positive bacterium responsible for a wide range of infections in humans and animals. We previously demonstrated that SA USA400 MW2 strain induces a G2/M phase delay in human HeLa cells. This phenomenon was associated with the accumulation of the cyclin-dependent kinase Cdk1/cdc2 and with the accumulation of unphosphorylated histone H3. Additionally we showed that the G2 phase was preferential for staphylococcal internalization and intracellular replication (1).The objectives of the study were -to identify the active substances, which are responsible for the cell cycle alteration, -to understand, how this alteration hijacks defense functions of the host cells.Using size exclusion chromatography of MW2 supernatant, followed by mass spectroscopy analysis, we identified Phenol-Soluble Modulin alpha (PSMα) peptides as the likely candidates for this effect. Indeed, synthetic PSMα1 and PSMα3 caused a G2/M phase transition delay. The implication of PSMα in cell cycle alteration was confirmed by comparison of wild type SA USA300 (strain LAC wt) with the isogenic mutant (LAC∆psmα), lacking the psmα operon that encodes PSMα1 to 4, for its internalization efficiency in HeLa cells. The decreased internalization rate of LAC∆psmα suggested a role of PSMα in host cell invasion. Furthermore, PSMα-induced G2/M-transition delay correlated with a decrease in the defensin genes expression suggesting a diminution of antibacterial functions of epithelial cells (2). Our results open new perspectives for the investigation of the mechanisms of the SA infection.
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Phenol-Soluble Modulin α induce G2/M phase transition delay in eukaryotic HeLa cells.
FASEB Journal, 2015Co-Authors: Martine Deplanche, Rachid El-aouar Filho, Emilie Ladier, Julien Jardin, Gwenaele Henry, Vasco Azevedo, Ludmila Alekseeva, Anderson Miyoshi, Laétitia Béraud, Frédéric LaurentAbstract:Staphylococcus aureus is a gram-positive bacterium responsible for a wide range of infections. Host cell cycle alteration is a sophisticated mechanism used by pathogens to hijack the defense functions of host cells. We previously demonstrated that S. aureus MW2 (USA400) bacteria induced a G2/M phase transition delay in HeLa cells. We demonstrate here that this activity is triggered by culture supernatant compounds. Using size exclusion chromatography of the MW2 supernatant, followed by mass spectroscopy analysis of corresponding peaks, we identified Phenol-Soluble Modulin α (PSMα) peptides as the likely candidates for this effect. Indeed, synthetic PSMα1 and PSMα3 caused a G2/M phase transition delay. The implication of PSMα in cell cycle alteration was confirmed by comparison of S. aureus Los Angeles County clone (LAC) wild-type with the isogenic mutant LAC∆psmα, which lacks the psmα operon encoding PSMα1-4. PSMα-induced G2/M transition delay correlated with a decrease in the defensin genes expression suggesting a diminution of antibacterial functions of epithelial cells. By testing the supernatant of S. aureus human clinical isolates, we found that the degree of G2/M phase transition delay correlated with PSMα1 production. We show that PSMs secreted by S. aureus alter the host cell cycle, revealing a newly identified mechanism for fostering an infection.