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1.
Proc Natl Acad Sci U S A ; 119(20): e2121586119, 2022 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-35533283

RESUMO

SignificanceThe formation of cross-α amyloids has been shown by crystallographic analysis of the highly cytolytic peptide PSMα3, a secreted virulence factor associated with the human pathogen Staphylococcus aureus. However, the relationship of the crystallographic cross-α structure to self-assembled filaments of PSMα3 and its relevance to other phenol-soluble modulin (PSM) peptides remained an open question. We report the cryo-electron microscopy structural analysis of three nanotubes derived from self-assembly of PSMα3 and PSMß2 peptides in aqueous solution. In each case, the nanotubes are derived from self-association of cross-α amyloid protofilaments. The self-assembly behavior of S. aureus PSMα3 and PSMß2 peptides provides strong evidence for the importance of the cross-α fold in self-assembled peptide and protein structures in general and for PSMs in particular.


Assuntos
Nanotubos , Staphylococcus aureus , Amiloide/química , Toxinas Bacterianas , Microscopia Crioeletrônica , Humanos , Peptídeos/química , Staphylococcus aureus/metabolismo
2.
Nat Commun ; 13(1): 2517, 2022 May 06.
Artigo em Inglês | MEDLINE | ID: mdl-35523796

RESUMO

Colonisation of humans by Staphylococcus aureus is a major risk factor for infection, yet the bacterial and host factors involved are not fully understood. The first step during skin colonisation is adhesion of the bacteria to corneocytes in the stratum corneum where the cornified envelope protein loricrin is the main ligand for S. aureus. Here we report a novel loricrin-binding protein of S. aureus, the cell wall-anchored fibronectin binding protein B (FnBPB). Single-molecule force spectroscopy revealed both weak and ultra-strong (2 nN) binding of FnBPB to loricrin and that mechanical stress enhanced the strength of these bonds. Treatment with a peptide derived from fibrinogen decreased the frequency of strong interactions, suggesting that both ligands bind to overlapping sites within FnBPB. Finally, we show that FnBPB promotes adhesion to human corneocytes by binding strongly to loricrin, highlighting the relevance of this interaction to skin colonisation.


Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Adesinas Bacterianas/química , Aderência Bacteriana , Fibronectinas/metabolismo , Humanos , Proteínas de Membrana , Ligação Proteica , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/metabolismo
3.
Acta Crystallogr F Struct Biol Commun ; 78(Pt 4): 144-149, 2022 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-35400666

RESUMO

Bacilliredoxins are small proteins that are involved in redox homeostasis in bacillithiol-producing bacteria. They reduce mixed bacillithiol disulfides on protected proteins through a disulfide-exchange reaction, restoring the thiol group on the target protein. Bacilliredoxins contain an unusual conserved CGC motif, and their exact catalytic mechanism remains unclear. Here, a 1.6 Šresolution X-ray crystallographic structure of the bacilliredoxin BrxA (YphP) from Staphylococcus aureus is presented. The structure contains bacillithiol in a mixed disulfide with Cys54, as well as a disulfide linkage at Cys56, which may play a role in dimer stabilization. The structure presented here will provide insight into the function of BrxA and other bacilliredoxins.


Assuntos
Firmicutes , Staphylococcus aureus , Proteínas de Bactérias/química , Cristalografia por Raios X , Dissulfetos/metabolismo , Firmicutes/metabolismo , Homeostase , Oxirredução , Staphylococcus aureus/metabolismo
4.
Molecules ; 27(8)2022 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-35458799

RESUMO

The expression of the efflux pump systems is the most important mechanism of antibiotic resistance in bacteria, as it contributes to reduced concentration and the subsequent inactivity of administered antibiotics. NorA is one of the most studied antibacterial targets used as a model for efflux-mediated resistance. The present study evaluated shikimate pathway-derived phenolic acids against NorA (PDB ID: 1PW4) as a druggable target in antibacterial therapy using in silico modelling and in vitro methods. Of the 22 compounds evaluated, sinapic acid (-9.0 kcal/mol) and p-coumaric acid (-6.3 kcal/mol) had the best and most prominent affinity for NorA relative to ciprofloxacin, a reference standard (-4.9 kcal/mol). A further probe into the structural stability and flexibility of the resulting NorA-phenolic acids complexes through molecular dynamic simulations over a 100 ns period revealed p-coumaric acid as the best inhibitor of NorA relative to the reference standard. In addition, both phenolic acids formed H-bonds with TYR 76, a crucial residue implicated in NorA efflux pump inhibition. Furthermore, the phenolic acids demonstrated favourable drug likeliness and conformed to Lipinski's rule of five for ADME properties. For the in vitro evaluation, the phenolic acids had MIC values in the range 31.2 to 62.5 µg/mL against S. aureus, and E. coli, and there was an overall reduction in MIC following their combination with ciprofloxacin. Taken together, the findings from both the in silico and in vitro evaluations in this study have demonstrated high affinity of p-coumaric acid towards NorA and could be suggestive of its exploration as a novel NorA efflux pump inhibitor.


Assuntos
Escherichia coli , Staphylococcus aureus , Antibacterianos/química , Proteínas de Bactérias/metabolismo , Ciprofloxacina/metabolismo , Ciprofloxacina/farmacologia , Escherichia coli/metabolismo , Testes de Sensibilidade Microbiana , Proteínas Associadas à Resistência a Múltiplos Medicamentos/metabolismo , Staphylococcus aureus/metabolismo
5.
Biochim Biophys Acta Proteins Proteom ; 1870(5): 140781, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35421609

RESUMO

The bifunctional flavin adenine dinucleotide synthetase (FADS) synthesizes the flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) co-factors essential for the function of flavoproteins. The Staphylococcus aureus FADS (SaFADS) produces FMN from riboflavin (RF) by ATP:riboflavin kinase (RFK) activity at its C-terminal domain. The N-terminal domain converts FMN to FAD under a reducing environment by FMN:ATP adenylyltransferase (FMNAT) activity which is reversible (FAD pyrophosphorylase activity). Herein, we investigated the role of F26 residue of the 24-GFFD-28 motif of SaFADS FMNAT domain, mostly conserved in the reducing agent-dependent FADSs. The steady-state kinetics studies showed changes in the KmATP values for mutants, indicating that the F26 residue is crucial for the FMNAT activity. Further, the FMNAT activity of the F26S mutant was observed to be higher than that of the wild-type SaFADS and its other variants at lower reducing agent concentration. In addition, the FADpp activity was inhibited by an excess of FAD substrate, which was more potent in the mutants. The altered orientation of the F26 side-chain observed in the molecular dynamics analysis suggested its plausible involvement in stabilizing FMN and ATP substrates in their respective binding pockets. Also, the SaFADS ternary complex formed with reduced FMN exhibited significant structural changes in the ß4n-ß5n and L3n regions compared to the oxidised FMN bound and apo forms of SaFADS. Overall, our data suggests the functional role of F26 residue in the FMNAT domain of SaFADS.


Assuntos
Mononucleotídeo de Flavina , Staphylococcus aureus , Trifosfato de Adenosina/metabolismo , Corynebacterium/metabolismo , Mononucleotídeo de Flavina/química , Flavina-Adenina Dinucleotídeo/metabolismo , Nucleotidiltransferases , Substâncias Redutoras , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo , Especificidade por Substrato
6.
Jt Dis Relat Surg ; 33(1): 193-202, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35361095

RESUMO

OBJECTIVES: In this experimental study, we aimed to investigate the specific value of receptor activator of nuclear factor kappa-Β ligand (RANKL) plasma level in osteomyelitis to show the bone destruction and to determine its correlation with classical markers of infection in mice model of osteomyelitis. MATERIALS AND METHODS: Sixty Balb/c female mice (30 to 40 g weight, 3.5 to 4 month-old) were divided into two groups: Controls (n=15) and study group (n=45). All mice underwent tibial decortication and received an injection of sclerosing agent into the intramedullary cavity. The next process was proceeded in two steps to observe the detectability of osteomyelitis-induced bone destruction (step 1) and treatment response (step 2) using the variables examined in our study. In step 1, the study group received 1 mL solution containing Staphylococcus aureus (S. aureus) bacteria (2X108 per mL) into the intramedullary cavity. Five mice from each group were sacrificed every seven days for three weeks and tibia and blood samples were obtained. In step 2, the remaining 30 infected mice were further divided into two groups to investigate the possible value of RANKL plasma level as a marker of treatment response. Fifteen of these mice received teicoplanin 20 mg/kg for four weeks, while the rest did not receive antibiotics. Eight mice from each group were sacrificed at the end of the second week and the remaining 14 mice were sacrificed at the end of four weeks. Complete blood count, procalcitonin level, C-reactive protein (CRP), and RANKL concentrations were measured from blood samples of each sacrificed mouse. RESULTS: Median RANKL concentration of the control subjects was significantly higher than recipients of intervention at the first and third weeks in step 1 where bone destruction of osteomyelitis was examined. No significant changes occurred in groups receiving and not receiving antimicrobial treatment in terms of RANKL, CRP, and procalcitonin levels throughout four weeks in step 2. The RANKL concentration was significantly correlated with colony growth in subjects allocated to the S. aureus inoculation group (r=-0.547, p=0.035). CONCLUSION: The RANKL levels in mice with S. aureus osteomyelitis are not correlated with colony growth or other markers of inflammation and not useful for monitoring the response to antimicrobial treatment during osteomyelitis.


Assuntos
Osteomielite , Staphylococcus aureus , Animais , Modelos Animais de Doenças , Feminino , Humanos , Ligantes , Camundongos , Osteomielite/diagnóstico , Osteomielite/tratamento farmacológico , Osteomielite/microbiologia , Ligante RANK/metabolismo , Staphylococcus aureus/metabolismo
7.
Pharmacology ; 107(5-6): 250-262, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35417907

RESUMO

INTRODUCTION: Mulberry (Morus alba L.) leaves are widely used in traditional Chinese medicine for their antioxidant, anti-inflammatory, antibacterial, anti-obesity, antidiabetic, antiatherosclerotic, and anticancer properties. The current study aimed to investigate the effect of mulberry leaf extract (MLE) on Staphylococcus aureus (S. aureus)-induced conjunctivitis (5 × 109 colony-forming units, 0.5 mL/eye) in a rabbit model. METHODS: Rabbits were treated with MLE (5 mL/kg·d-1 and 10 mL/kg·d-1), 0.9% saline, pearl bright eye (PBE) drops, or erythromycin eye ointment (EEO) group for 5 days. The ocular infection symptoms, bacterial negative conversion rate, and conjunctival histopathological changes of rabbits in each group were observed. The expression of caspase-1, apoptosis-associated speck-like protein containing a caspase recruitment domain, NOD-like receptor leucine-rich pyrin domain-containing protein 3 (NLRP3), interleukin (IL)-18, IL-6, IL-1ß, TNFα, Keap1, and nuclear factor erythroid 2-related factor 2 (Nrf2) in conjunctival tissue of rabbits were detected by quantitative real-time reverse transcription PCR and/or Western blot analysis. RESULTS: The results showed that MLE treatment significantly reduced the clinical sign scores of conjunctivitis, alleviated clinical signs, and decreased bacterial load, and histological damage in a time- and dose-dependent manner was compared to that in the control group. The antibacterial and anti-inflammatory activities of MLE (10 mL/kg·d-1) were similar to those of the positive control drug PBE and EEO. In addition, MLE significantly decreased the levels of pro-inflammatory cytokines, downregulated the NLRP3 inflammasome, and upregulated the Nrf2 system. CONCLUSIONS: MLE is effective in alleviating S. aureus-induced conjunctivitis in rabbits, and this mechanism is associated with the inhibition of the NLRP3 inflammasome and activation of the Nrf2 system to regulate pro-inflammatory signaling.


Assuntos
Conjuntivite , Morus , Infecções Estafilocócicas , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Conjuntivite/tratamento farmacológico , Citocinas/metabolismo , Regulação para Baixo , Inflamassomos , Interleucina-1beta/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/genética , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Coelhos , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/metabolismo , Regulação para Cima
8.
Microbiol Spectr ; 10(2): e0276721, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35377191

RESUMO

Aminoglycoside antibiotics rely on the proton motive force to enter the bacterial cell, and facultative anaerobes like Staphylococcus aureus can shift energy generation from respiration to fermentation, becoming tolerant of aminoglycosides. Following this metabolic shift, high concentrations of aminoglycosides are required to eradicate S. aureus infections, which endangers the host due to the toxicity of aminoglycosides. Membrane-disrupting molecules prevent aminoglycoside tolerance in S. aureus by facilitating passive entry of the drug through the membrane. Polyunsaturated fatty acids (PUFAs) increase membrane permeability when incorporated into S. aureus. Here, we report that the abundant host-derived PUFA arachidonic acid increases the susceptibility of S. aureus to aminoglycosides, decreasing the aminoglycoside concentration needed to kill S. aureus. We demonstrate that PUFAs and aminoglycosides synergize to kill multiple strains of S. aureus, including both methicillin-resistant and -susceptible S. aureus. We also present data showing that PUFAs and aminoglycosides effectively kill S. aureus small colony variants, strains that are particularly recalcitrant to killing by many antibiotics. We conclude that cotreatment with PUFAs, which are molecules with low host toxicity, and aminoglycosides decreases the aminoglycoside concentration necessary to kill S. aureus, lowering the toxic side effects to the host associated with prolonged aminoglycoside exposure. IMPORTANCE Staphylococcus aureus infects every niche of the human host, and these infections are the leading cause of Gram-positive sepsis. Aminoglycoside antibiotics are inexpensive, stable, and effective against many bacterial infections. However, S. aureus can shift its metabolism to become tolerant of aminoglycosides, requiring increased concentrations and/or longer courses of treatment, which can cause severe host toxicity. Here, we report that polyunsaturated fatty acids (PUFAs), which have low host toxicity, disrupt the S. aureus membrane, making the pathogen susceptible to aminoglycosides. Additionally, cotreatment with aminoglycosides is effective at killing S. aureus small colony variants, strains that are difficult to treat with antibiotics. Taken together, the data presented herein show the promise of PUFA cotreatment to increase the efficacy of aminoglycosides against S. aureus infections and decrease the risk to the human host of antibiotic-induced toxicity.


Assuntos
Aminoglicosídeos , Infecções Estafilocócicas , Aminoglicosídeos/metabolismo , Aminoglicosídeos/farmacologia , Aminoglicosídeos/uso terapêutico , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Ácidos Graxos Insaturados/farmacologia , Humanos , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/metabolismo
9.
Front Immunol ; 13: 839502, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35370996

RESUMO

The clinical severity of Staphylococcus aureus (S. aureus) respiratory infection correlates with antibacterial gene signature. S. aureus infection induces the expression of an antibacterial gene, as well as a central stress response gene, thus activating transcription factor 3 (ATF3). ATF3-deficient mice have attenuated protection against lethal S. aureus pneumonia and have a higher bacterial load. We tested the hypothesis that ATF3-related protection is based on the increased function of macrophages. Primary marrow-derived macrophages (BMDM) were used in vitro to determine the mechanism through which ATF3 alters the bacterial-killing ability. The expression of ATF3 correlated with the expression of antibacterial genes. Mechanistic studies showed that ATF3 upregulated antibacterial genes, while ATF3-deficient cells and lung tissues had a reduced level of antibacterial genes, which was accompanied by changes in the antibacterial process. We identified multiple ATF3 regulatory elements in the antibacterial gene promoters by chromatin immunoprecipitation analysis. In addition, Wild type (WT) mice had higher F4/80 macrophage migration in the lungs compared to ATF3-null mice, which may correlate with actin filament severing through ATF3-targeted actin-modifying protein gelsolin (GSN) for the macrophage cellular motility. Furthermore, ATF3 positively regulated inflammatory cytokines IL-6 and IL-12p40 might be able to contribute to the infection resolution. These data demonstrate a mechanism utilized by S. aureus to induce ATF3 to regulate antibacterial genes for antimicrobial processes within the cell, and to specifically regulate the actin cytoskeleton of F4/80 macrophages for their migration.


Assuntos
Fator 3 Ativador da Transcrição , Staphylococcus aureus , Fator 3 Ativador da Transcrição/genética , Fator 3 Ativador da Transcrição/metabolismo , Animais , Antibacterianos , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Macrófagos , Camundongos , Camundongos Knockout , Staphylococcus aureus/metabolismo
10.
J Immunol ; 208(7): 1632-1641, 2022 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-35321878

RESUMO

Highly pathogenic Staphylococcus aureus strains produce phenol-soluble modulins (PSMs), which are N-formylated peptides. Nanomolar concentrations of PSMα2 are recognized by formyl peptide receptor 2 (FPR2), but unlike the prototypic FPR2 agonist WKYMVM, PSMα2 is a biased signaling agonist. The truncated N-terminal PSMα2 variant, consisting of the five N-terminal residues, is no longer recognized by FPR2, showing that the C-terminal part of PSMα2 confers FPR2 selectivity, whereas the N-terminal part may interact with the FPR1 binding site. In the current study, a combined pharmacological and genetic approach involving primary human neutrophils and engineered FPR knock-in and knockout cells was used to gain molecular insights into FPR1 and FPR2 recognition of formyl peptides as well as the receptor downstream signaling induced by these peptides. In comparison with the full-length PSMα2, we show that the peptide in which the N-terminal part of PSMα2 was replaced by fMet-Ile-Phe-Leu (an FPR1-selective peptide agonist) potently activates both FPRs for production of superoxide anions and ß-arrestin recruitment. A shortened analog of PSMα2 (PSMα21-12), lacking the nine C-terminal residues, activated both FPR1 and FPR2 to produce reactive oxygen species, whereas ß-arrestin recruitment was only mediated through FPR1. However, a single amino acid replacement (Gly-2 to Ile-2) in PSMα21-12 was sufficient to alter FPR2 signaling to include ß-arrestin recruitment, highlighting a key role of Gly-2 in conferring FPR2-biased signaling. In conclusion, we provide structural insights into FPR1 and FPR2 recognition as well as the signaling induced by interaction with formyl peptides derived from PSMα2, originating from S. aureus bacteria.


Assuntos
Receptores de Formil Peptídeo , Staphylococcus aureus , Toxinas Bacterianas , Humanos , Neutrófilos/metabolismo , Peptídeos/metabolismo , Receptores de Formil Peptídeo/metabolismo , Receptores de Lipoxinas/química , Staphylococcus aureus/metabolismo
11.
Gene ; 825: 146400, 2022 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-35306116

RESUMO

Periprosthetic joint infection (PJI), a devastating complication of total joint replacement, is of incompletely understood pathogenesis and may sometimes be challenging to clinically distinguish from other causes of arthroplasty failure. We characterized human gene expression in 93 specimens derived from surfaces of resected arthroplasties, comparing transcriptomes of subjects with infection- versus non-infection-associated arthroplasty failure. Differential gene expression analysis confirmed 28 previously reported potential biomarkers of PJI, including bactericidal/permeability increasing protein (BPI), cathelicidin antimicrobial peptide (CAMP), C-C-motif chemokine ligand 3 (CCL3), 4(CCL4) and C-X-C-motif chemokine ligand 2 (CXCL2), colony stimulating factor 2 receptor beta (CSF2RB), colony stimulating factor 3 (CSF3), alpha-defensin (DEFA4), Fc fragment of IgG receptor 1B (CD64B), intercellular adhesion molecule 1 (ICAM1), interferon gamma (IFNG), interleukin 13 receptor subunit alpha 2 (IL13RA2), interleukin 17D (IL17D), interleukin 1 (IL1A, IL1B, IL1RN), interleukin 2 receptors (IL2RA, IL2RG), interleukin 5 receptor (IL5RA), interleukin 6 (IL6), interleukin 8 (IL8), lipopolysaccharide binding protein (LBP), lipocalin (LCN2), lactate dehydrogenase C (LDHC), lactotransferrin (LTF), matrix metallopeptidase 3 (MMP3), peptidase inhibitor 3 (PI3), and vascular endothelial growth factor A (VEGFA), and identified three novel molecules of potential diagnostic use for detection of PJI, namely C-C-motif chemokine ligand CCL20, coagulation factor VII (F7), and B cell receptor FCRL4. Comparative analysis of infections caused by staphylococci versus bacteria other than staphylococci and Staphylococcus aureus versus Staphylococcus epidermidis showed elevated expression of interleukin 13 (IL13), IL17D, and MMP3 in staphylococcal infections, and of IL1B, IL8, and platelet factor PF4V1 in S. aureus compared to S. epidermidis infections. Pathway analysis of over-represented genes suggested activation of host immune response and cellular maintenance and repair functions in response to invasion of infectious agents. The data presented provides new potential targets for diagnosis of PJI and for differentiation of PJI caused by different infectious agents.


Assuntos
Artrite Infecciosa , Infecções Relacionadas à Prótese , Infecções Estafilocócicas , Artrite Infecciosa/diagnóstico , Artrite Infecciosa/metabolismo , Artrite Infecciosa/microbiologia , Biomarcadores/análise , Fatores Estimuladores de Colônias , Humanos , Interleucina-8 , Ligantes , Metaloproteinase 3 da Matriz/metabolismo , Infecções Relacionadas à Prótese/diagnóstico , Infecções Relacionadas à Prótese/genética , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/metabolismo , Líquido Sinovial/metabolismo , Transcriptoma , Fator A de Crescimento do Endotélio Vascular
12.
J Inorg Biochem ; 230: 111775, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-35247855

RESUMO

Non-canonical heme oxygenases are enzymes that degrade heme to non-biliverdin products within bacterial heme iron acquisition pathways. These enzymes all contain a conserved second-sphere Trp residue that is essential for enzymatic turnover. Here, UV/Vis absorption (Abs) and circular dichroism (CD) spectroscopies were employed to show that the W67F variant of IsdG perturbs the heme substrate conformation. In general, a dynamic equilibrium between "planar" and "ruffled" substrate conformations exists within non-canonical heme oxygenases, and that the second-sphere Trp favors population of the "ruffled" substrate conformation. 1H nuclear magnetic resonance and magnetic CD spectroscopies were used to characterize the electronic structures of IsdG and IsdI variants with different substrate conformational distributions. These data revealed that the "ruffled" substrate conformation promotes partial porphyrin-to­iron electron transfer, which makes the meso carbons of the porphyrin ring susceptible to radical attack. Finally, UV/Vis Abs spectroscopy was utilized to quantify the enzymatic rates, and electrospray ionization mass spectrometry was used to identify the product distributions, for variants of IsdG with altered substrate conformational distributions. In general, the rate of heme oxygenation by non-canonical heme oxygenases depends upon the population of the "ruffled" substrate conformation. Also, the production of staphylobilin or mycobilin by these enzymes is correlated with the population of the "ruffled" substrate conformation, since variants that favor population of the "planar" substrate conformation yield significant amounts of biliverdin. These data can be understood within the framework of a concerted rearrangement mechanism for the monooxygenation of heme to meso-hydroxyheme by non-canonical heme oxygenases.


Assuntos
Heme , Staphylococcus aureus , Proteínas de Bactérias/química , Catálise , Heme/química , Heme Oxigenase (Desciclizante)/química , Ferro , Oxigenases/química , Staphylococcus aureus/metabolismo
13.
Microbiol Spectr ; 10(2): e0010622, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35297656

RESUMO

Many bacterial and fungal pathogens cause disease across mucosal surfaces, and to a lesser extent through skin surfaces. Pathogens that potentially cause disease vaginally across epithelial cells include Staphylococcus aureus, group A and B streptococci, Escherichia coli, Neisseria gonorrhoeae, and Candida albicans. We have previously shown that staphylococcal and streptococcal superantigens induce inflammatory chemokines from vaginal epithelial cells through the immune costimulatory molecule CD40 through use of a CRISPR cas9 knockout mutant and complemented epithelial cell line. In this study, we show that the potential vaginal pathogens S. aureus, group A and B streptococci, E. coli, an Enterococcus faecalis strain, and C. albicans in part use CD40 to stimulate interleukin-8 (IL-8) production from human vaginal epithelial cells. In contrast, N. gonorrhoeae does not appear to use CD40 to signal IL-8 production. Normal flora Lactobacillus crispatus and an Enterococcus faecalis strain that produces reutericyclin do not induce IL-8. These data indicate that many potential pathogens, but no normal commensals, induce IL-8 to help disrupt the human vaginal epithelial barrier through CD40, thus providing a potential therapeutic target for drug development. IMPORTANCE Most bacterial and fungal pathogens cause disease across mucosal, and to a lesser extent, skin barriers with the help of induced chemokines from epithelial cells. In this study, we showed that potential vaginal pathogens Staphylococcus aureus, group A and B streptococci, some Enterococcus faecalis strains, Escherichia coli, and Candida albicans use the immune costimulatory molecule CD40 to induce the chemokine interleukin-8 production. In contrast, Neisseria gonorrhoeae does not use CD40 to stimulate interleukin-8. Normal flora lactobacilli and at least one E. faecalis strain do not induce interleukin-8.


Assuntos
Infecções por Escherichia coli , Infecções Estafilocócicas , Candida albicans/metabolismo , Quimiocinas/metabolismo , Células Epiteliais/microbiologia , Escherichia coli/metabolismo , Feminino , Humanos , Interleucina-8/metabolismo , Staphylococcus aureus/metabolismo , Vagina/microbiologia
14.
Microbiol Spectr ; 10(2): e0234021, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35319277

RESUMO

The dramatic increase of methicillin-resistant Staphylococcus aureus (MRSA) poses a great challenge to the treatment of Staphylococcus aureus (S. aureus) infections. Therefore, there is an urgent need to identify novel anti-infective agents to attack new targets to overcome antibiotic resistance. Casein hydrolase P (ClpP) is a key virulence factor in S. aureus to maintain cellular homeostasis. We screened from flavonoids and finally determined that quercetin could effectively attenuate the virulence of MRSA. The results of the thermal shift assay showed that quercetin could bind to ClpP and reduce the thermal stability of ClpP, and the KD value between quercetin and ClpP was 197 nM as determined by localized surface plasmon resonance. We found that quercetin exhibited a protective role of a mouse model of MRSA-induced lethal infection in a murine model. Based on the above facts, quercetin, as a ClpP inhibitor, could be further developed as a potential candidate for antivirulence agents to combat S. aureus infections. IMPORTANCE The resistance of Staphylococcus aureus (S. aureus) to various antibiotics has increased dramatically, and thus the development of new anti-infective drugs with new targets is urgently needed to combat resistance. Caseinolytic peptidase P (ClpP) is a casein hydrolase that has been shown to regulate a variety of important virulence factors in S. aureus. Here, we found that quercetin, a small-molecule compound from traditional Chinese herbal flavonoids, effectively inhibits ClpP activity. Quercetin attenuates the expression of multiple virulence factors in S. aureus and effectively protects mice from lethal pneumonia caused by MRSA. In conclusion, we determined that quercetin is a ClpP inhibitor and an effective lead compound for the development of a virulence factor-based treatment for S. aureus infection.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Pneumonia , Infecções Estafilocócicas , Animais , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Caseínas/farmacologia , Caseínas/uso terapêutico , Flavonoides/farmacologia , Flavonoides/uso terapêutico , Camundongos , Testes de Sensibilidade Microbiana , Peptidil Dipeptidase A/farmacologia , Peptidil Dipeptidase A/uso terapêutico , Pneumonia/tratamento farmacológico , Quercetina/farmacologia , Quercetina/uso terapêutico , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/metabolismo , Virulência , Fatores de Virulência/metabolismo
15.
Microb Pathog ; 165: 105466, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35247499

RESUMO

BACKGROUND: Intracellular Staphylococcus aureus (S. aureus) infection is generally persistent, recurrent and difficult to treat due to the poor availability of antibiotics within macrophages cells and the lack of ideal diagnostic markers. Circular RNAs (circRNAs), with covalently closed circular structures, exists in the serum stably and is not easily degraded by nucleases. Besides, circRNAs play a pivotal in the eukaryotic regulation of genes expression and served as biomarkers in variety disease including microbial infections. However, the function of host circRNAs in intracellular S. aureus infection remains largely unclear. METHODS: In this study, the circRNAs expression profile was investigated by RNA sequencing technology in both S. aureus-infected THP-1 derived macrophages and mock control cells. The differentially expressed circRNAs (DE circRNAs) with a fold-change >1.5 (p < 0.05) are analyzed using functional pathway clustering prediction. Then, RT-qPCR was performed to verify the top 2 up-regulated circRNAs in the THP-1 cell and human serum samples so as to evaluate the value of circRNAs for S. aureus diagnosis. RESULTS: An intracellular survival THP-1 derived macrophages model of S. aureus infection was established. A total of 5,299 circRNAs were identified in human THP-1 derived macrophages infected with intracellular S. aureus. There were 61 DE circRNAs with a fold-change >1.5 (p < 0.05) after S. aureus infection. Among them, 22 circRNAs were up-regulated while 39 circRNAs down-regulated. GO and KEGG pathway analysis demonstrated that DE circRNAs were enriched in the processes such as Neurotrophin, Pyruvate metabolism and Notch signaling pathway. Moreover, hsa_circ_0000311 and chr13:43500472-43544806-(novel) were verified to be significantly upregulated in THP-1 derived macrophages and human serum samples between two groups. Finally, the networks of circRNA-miRNA-mRNA based on these two circRNAs were constructed respectively. CONCLUSION: Our study provides the first profile analysis of host circRNAs involved in intracellular S. aureus infection, which may serve as biomarkers for S. aureus diagnosis and contribute to the understanding of S. aureus evasion mechanisms.


Assuntos
MicroRNAs , RNA Circular , Biomarcadores , Humanos , Macrófagos/metabolismo , MicroRNAs/genética , RNA Circular/genética , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo
16.
Nat Commun ; 13(1): 1525, 2022 03 21.
Artigo em Inglês | MEDLINE | ID: mdl-35314690

RESUMO

A central question concerning natural competence is why orthologs of competence genes are conserved in non-competent bacterial species, suggesting they have a role other than in transformation. Here we show that competence induction in the human pathogen Staphylococcus aureus occurs in response to ROS and host defenses that compromise bacterial respiration during infection. Bacteria cope with reduced respiration by obtaining energy through fermentation instead. Since fermentation is energetically less efficient than respiration, the energy supply must be assured by increasing the glycolytic flux. The induction of natural competence increases the rate of glycolysis in bacteria that are unable to respire via upregulation of DNA- and glucose-uptake systems. A competent-defective mutant showed no such increase in glycolysis, which negatively affects its survival in both mouse and Galleria infection models. Natural competence foster genetic variability and provides S. aureus with additional nutritional and metabolic possibilities, allowing it to proliferate during infection.


Assuntos
Infecções Estafilocócicas , Staphylococcus aureus , Animais , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Metabolismo dos Carboidratos , Fermentação , Glicólise/genética , Camundongos , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo
17.
PLoS One ; 17(3): e0265774, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35324969

RESUMO

Staphylococcus aureus employs a multitude of immune-evasive tactics to circumvent host defenses including the complement system, a component of innate immunity central to controlling bacterial infections. With antibiotic resistance becoming increasingly common, there is a dire need for novel therapies. Previously, we have shown that S. aureus binds the complement regulator factor H (FH) via surface protein SdrE to inhibit complement. To address the need for novel therapeutics and take advantage of the FH:SdrE interaction, we examined the effect of a fusion protein comprised of the SdrE-interacting domain of FH coupled with IgG Fc on complement-mediated opsonophagocytosis and bacterial killing of community associated methicillin-resistant S. aureus. S. aureus bound significantly more FH-Fc compared to Fc-control proteins and FH-Fc competed with serum FH for S. aureus binding. FH-Fc treatment increased C3-fragment opsonization of S. aureus for both C3b and iC3b, and boosted generation of the anaphylatoxin C5a. In 5 and 10% serum, FH-Fc treatment significantly increased S. aureus killing by polymorphonuclear cells. This anti-staphylococcal effect was evident in 75% (3/4) of clinical isolates tested. This study demonstrates that FH-Fc fusion proteins have the potential to mitigate the protective effects of bound serum FH rendering S. aureus more vulnerable to the host immune system. Thus, we report the promise of virulence-factor-targeted fusion-proteins as an avenue for prospective anti-staphylococcal therapeutic development.


Assuntos
Fator H do Complemento , Staphylococcus aureus Resistente à Meticilina , Complemento C3b/metabolismo , Proteínas do Sistema Complemento/metabolismo , Staphylococcus aureus Resistente à Meticilina/metabolismo , Ligação Proteica , Staphylococcus aureus/metabolismo
18.
ACS Biomater Sci Eng ; 8(4): 1476-1485, 2022 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-35263544

RESUMO

Research into materials for medical application draws inspiration from naturally occurring or synthesized surfaces, just like many other research directions. For medical application of materials, particular attention has to be paid to biocompatibility, osseointegration, and bacterial adhesion behavior. To understand their properties and behavior, experimental studies with natural materials such as teeth are strongly required. The results, however, may be highly case-dependent because natural surfaces have the disadvantage of being subject to wide variations, for instance in their chemical composition, structure, morphology, roughness, and porosity. A synthetic surface which mimics enamel in its performance with respect to bacterial adhesion and biocompatibility would, therefore, facilitate systematic studies much better. In this study, we discuss the possibility of using hydroxyapatite (HAp) pellets to simulate the surfaces of teeth and show the possibility and limitations of using a model surface. We performed single-cell force spectroscopy with single Staphylococcus aureus cells to measure adhesion-related parameters such as adhesion force and rupture length of cell wall proteins binding to HAp and enamel. We also examine the influence of blood plasma and saliva on the adhesion properties of S. aureus. The results of these measurements are matched to water wettability, elemental composition of the samples, and the change in the macromolecules adsorbed over time on the surface. We found that the adhesion properties of S. aureus were similar on HAp and enamel samples under all conditions: Significant decreases in adhesion strength were found equally in the presence of saliva or blood plasma on both surfaces. We therefore conclude that HAp pellets are a good alternative for natural dental material. This is especially true when slight variations in the physicochemical properties of the natural materials may affect the experimental series.


Assuntos
Durapatita , Staphylococcus aureus , Esmalte Dentário , Durapatita/química , Durapatita/metabolismo , Durapatita/farmacologia , Análise Espectral , Staphylococcus aureus/metabolismo , Propriedades de Superfície
19.
mBio ; 13(2): e0340421, 2022 Apr 26.
Artigo em Inglês | MEDLINE | ID: mdl-35357211

RESUMO

Cell division and cell wall synthesis in staphylococci need to be precisely coordinated and controlled to allow the cell to multiply while maintaining its nearly spherical shape. The mechanisms ensuring correct placement of the division plane and synthesis of new cell wall have been studied intensively. However, hitherto unknown factors and proteins are likely to play key roles in this complex interplay. Here, we identified and investigated a protein with a major influence on cell morphology in Staphylococcus aureus. The protein, named SmdA (for staphylococcal morphology determinant A), is a membrane protein with septum-enriched localization. By CRISPRi knockdown and overexpression combined with different microscopy techniques, we demonstrated that proper levels of SmdA were necessary for cell division, including septum formation and cell splitting. We also identified conserved residues in SmdA that were critical for its functionality. Pulldown and bacterial two-hybrid interaction experiments showed that SmdA interacted with several known cell division and cell wall synthesis proteins, including penicillin-binding proteins (PBPs) and EzrA. Notably, SmdA also affected susceptibility to cell wall targeting antibiotics, particularly in methicillin-resistant S. aureus (MRSA). Together, our results showed that S. aureus was dependent on balanced amounts of membrane attached SmdA to carry out proper cell division. IMPORTANCE Staphylococcus aureus is an important human and animal pathogen. Antibiotic resistance is a major problem in the treatment of staphylococcal infections, and cell division and cell wall synthesis factors have previously been shown to modulate susceptibility to antibiotics in this species. Here, we investigated the function of a protein named SmdA, which was identified based on its septal localization and knockdown phenotype resulting in defective cellular morphologies. We demonstrated that this protein was critical for normal cell division in S. aureus. Depletion of SmdA sensitized resistant staphylococci to ß-lactam antibiotics. This work revealed a new staphylococcal cell division factor and a potential future target for narrow-spectrum antimicrobials or compounds to resensitize antibiotic-resistant staphylococcal strains.


Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Humanos , Staphylococcus aureus Resistente à Meticilina/metabolismo , Proteínas de Ligação às Penicilinas/genética , Proteínas de Ligação às Penicilinas/metabolismo , Staphylococcus/metabolismo , Staphylococcus aureus/genética , Staphylococcus aureus/metabolismo
20.
Microb Cell Fact ; 21(1): 40, 2022 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-35292023

RESUMO

BACKGROUND: Endolysins are peptidoglycan hydrolases with promising use as environment-friendly antibacterials mainly when used topically. However, in general, endolysin expression is hampered by its low solubility. Thus, a critical point in endolysin industrial production is optimizing their expression, including improvement of solubility and recovery from cell extracts. RESULTS: We report the expression of two endolysins encoded in the genome of phages infecting Staphylococcus aureus. Expression was optimized through changes in the concentration of the inducer and growth temperature during the expression. Usually, only 30-40% of the total endolysin was recovered in the soluble fraction. Co-expression of molecular chaperones (DnaK, GroEL) or N-term fusion tags endowed with increased solubility (DsbC, Trx, Sumo) failed to improve that yield substantially. Inclusion of osmolytes (NaCl, CaCl2, mannitol, glycine betaine, glycerol and trehalose) or tensioactives (Triton X-100, Tween 20, Nonidet P-40, CHAPS, N-lauroylsarcosine) in the cell disruption system (in the absence of any molecular chaperone) gave meager improvements excepted by N-lauroylsarcosine which increased recovery to 54% of the total endolysin content. CONCLUSION: This is the first attempt to systematically analyze methods for increasing yields of recombinant endolysins. We herein show that neither solubility tags nor molecular chaperones co-expression are effective to that end, while induction temperature, (His)6-tag location and lysis buffer additives (e.g. N-lauroylsarcosine), are sensible strategies to obtain higher levels of soluble S. aureus endolysins.


Assuntos
Bacteriófagos , Escherichia coli , Bacteriófagos/genética , Endopeptidases/genética , Endopeptidases/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Staphylococcus aureus/metabolismo
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