Numbers of pathogenic bacteria can induce apoptosis in human host cells and modulate the cellular pathways responsible for inducing or inhibiting apoptosis. These pathogens are significantly recognized by host proteins and provoke the multitude of several signaling pathways and alter the cellular apoptotic stimuli. This process leads the bacterial entry into the mammalian cells and evokes a variety of responses like phagocytosis, release of mitochondrial cytochrome c, secretion of bacterial effectors, release of both apoptotic and inflammatory cytokines, and the triggering of apoptosis. Several mechanisms are involved in bacteria-induced apoptosis including, initiation of the endogenous death machinery, pore-forming proteins, and secretion of superantigens. Either small molecules or proteins may act as a binding partner responsible for forming the protein complexes and regulate enzymatic activity via protein-protein interactions. The bacteria induce apoptosis, attack the human cell and gain control over various types of cells and tissue. Since these processes are intricate in the defense mechanisms of host organisms against pathogenic bacteria and play an important function in host-pathogen interactions. In this chapter, we focus on the various bacterial-induced apoptosis mechanisms in host cells and discuss the important proteins and bacterial effectors that trigger the host cell apoptosis. The structural characterization of bacterial effector proteins and their interaction with human host cells are also considered.
- MeSH
- apoptóza imunologie MeSH
- Bacteria * imunologie patogenita MeSH
- bakteriální infekce imunologie MeSH
- bakteriální proteiny * chemie imunologie MeSH
- faktory virulence * chemie imunologie MeSH
- lidé MeSH
- vztahy mezi strukturou a aktivitou MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
Hemolytic factor production by pathogenic Candida species is considered an important attribute in promoting survival within the mammal host through the ability to assimilate iron from the hemoglobin-heme group. Hemolytic capability has been evaluated for Candida species based on hemolysis zones on plate assay, analysis of hemolytic activity in liquid culture medium, and hemolysis from cell-free culture broth. The production of hemolytic factor is variable among Candida species, where C. parapsilosis is the less hemolytic species. In general, no intraspecies differences in beta-hemolytic activities are found among isolates belonging to C. albicans, C. glabrata, C. krusei, C. tropicalis, and C. parapsilosis. The production of hemolytic factor by Candida species is affected by several factors such as glucose supplementation in the culture medium, blood source, presence of erythrocytes and hemoglobin, and presence of electrolytes. On the basis of existing achievements, more researches are still needed in order to extend our knowledge about the biochemical nature of hemolytic molecules produced by distinct Candida species, the mechanism of hemolysis, and the molecular basis of the hemolytic factor expression.
- MeSH
- Candida klasifikace metabolismus fyziologie MeSH
- druhová specificita MeSH
- faktory virulence biosyntéza chemie MeSH
- hemolýza * MeSH
- kandidemie mikrobiologie patologie MeSH
- kultivační média chemie metabolismus MeSH
- lidé MeSH
- membránové glykoproteiny metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- přehledy MeSH
- MeSH
- DNA bakterií genetika chemie MeSH
- faktory virulence * genetika chemie imunologie MeSH
- Francisella * enzymologie genetika patogenita MeSH
- genetické lokusy fyziologie genetika MeSH
- kaspasa 9 * genetika chemie MeSH
- regulace genové exprese u bakterií fyziologie genetika MeSH
- štěpení DNA MeSH
- Publikační typ
- novinové články MeSH
Aspergillus fumigatus is an important allergen and opportunistic pathogen. Similarly to many other pathogens, it is able to produce lectins that may be involved in the host-pathogen interaction. We focused on the lectin AFL, which was prepared in recombinant form and characterized. Its binding properties were studied using hemagglutination and glycan array analysis. We determined the specificity of the lectin towards l-fucose and fucosylated oligosaccharides, including α1-6 linked core-fucose, which is an important marker for cancerogenesis. Other biologically relevant saccharides such as sialic acid, d-mannose or d-galactose were not bound. Blood group epitopes of the ABH and Lewis systems were recognized, Le(Y) being the preferred ligand among others. To provide a correlation between the observed functional characteristics and structural basis, AFL was crystallized in a complex with methyl-α,L-selenofucoside and its structure was solved using the SAD method. Six binding sites, each with different compositions, were identified per monomer and significant differences from the homologous AAL lectin were found. Structure-derived peptides were utilized to prepare anti-AFL polyclonal antibodies, which suggested the presence of AFL on the Aspergillus' conidia, confirming its expression in vivo. Stimulation of human bronchial cells by AFL led to IL-8 production in a dose-dependent manner. AFL thus probably contributes to the inflammatory response observed upon the exposure of a patient to A. fumigatus. The combination of affinity to human epithelial epitopes, production by conidia and pro-inflammatory activity is remarkable and shows that AFL might be an important virulence factor involved in an early stage of A. fumigatus infection.
- MeSH
- Aspergillus fumigatus chemie MeSH
- aspergilóza imunologie MeSH
- bronchy cytologie mikrobiologie MeSH
- epitopy chemie MeSH
- faktory virulence chemie MeSH
- fukosa chemie MeSH
- galaktosa chemie MeSH
- genom fungální MeSH
- hemaglutinace MeSH
- interakce hostitele a patogenu MeSH
- interleukin-8 metabolismus MeSH
- kyselina N-acetylneuraminová chemie MeSH
- lektiny chemie MeSH
- lidé MeSH
- mannosa chemie MeSH
- molekulární sekvence - údaje MeSH
- oligosacharidy chemie MeSH
- sekvence aminokyselin MeSH
- sekvenční homologie aminokyselin MeSH
- sekvenční seřazení MeSH
- spory hub chemie MeSH
- vazebná místa MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
FTH_0069 is a previously uncharacterized strongly immunoreactive protein that has been proposed to be a novel virulence factor in Francisella tularensis. Here, the glycan structure modifying two C-terminal peptides of FTH_0069 was identified utilizing high resolution, high mass accuracy mass spectrometry, combined with in-source CID tandem MS experiments. The glycan observed at m/z 1156 was determined to be a hexasaccharide, consisting of two hexoses, three N-acetylhexosamines, and an unknown monosaccharide containing a phosphate group. The monosaccharide sequence of the glycan is tentatively proposed as X-P-HexNAc-HexNAc-Hex-Hex-HexNAc, where X denotes the unknown monosaccharide. The glycan is identical to that of DsbA glycoprotein, as well as to one of the multiple glycan structures modifying the type IV pilin PilA, suggesting a common biosynthetic pathway for the protein modification. Here, we demonstrate that the glycosylation of FTH_0069, DsbA, and PilA was affected in an isogenic mutant with a disrupted wbtDEF gene cluster encoding O-antigen synthesis and in a mutant with a deleted pglA gene encoding pilin oligosaccharyltransferase PglA. Based on our findings, we propose that PglA is involved in both pilin and general F. tularensis protein glycosylation, and we further suggest an inter-relationship between the O-antigen and the glycan synthesis in the early steps in their biosynthetic pathways.
- MeSH
- faktory virulence chemie genetika metabolismus MeSH
- Francisella tularensis genetika metabolismus patogenita MeSH
- glykosylace MeSH
- molekulární sekvence - údaje MeSH
- multigenová rodina MeSH
- mutace MeSH
- O-antigeny chemie genetika metabolismus MeSH
- proteiny fimbrií chemie genetika metabolismus MeSH
- sacharidové sekvence MeSH
- sekvence aminokyselin MeSH
- tandemová hmotnostní spektrometrie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
The facultative intracellular bacterium Francisella tularensis is the causal agent of the serious infectious disease tularemia. Despite the dynamic progress, which has been made in last few years, important questions regarding Francisella pathogenicity still remain to be answered. Generally, secreted proteins play an important role in pathogenicity of intracellular microbes. In this study, we investigated the protein composition of the culture filtrate proteins of highly virulent F. tularensis subsp. tularensis, strain SCHU S4 and attenuated F. tularensis subsp. holarctica, live vaccine strain using a comparative proteomic analysis. The majority of proteins identified in this study have been implicated in virulence mechanisms of other pathogens, and several have been categorized as having moonlighting properties; those that have more than one unrelated function. This profiling study of secreted proteins resulted in the unique detection of acid phosphatase (precursor) A (AcpA), β-lactamase, and hypothetical protein FTT0484 in the highly virulent strain SCHU S4 secretome. The release of AcpA may be of importance for F. tularensis subsp. tularensis virulence due to the recently described AcpA role in the F. tularensis escape from phagosomes.
Francisella tularensis (F. tularensis) is highly infectious for humans via aerosol route and untreated infections with the highly virulent subsp. tularensis can be fatal. Our knowledge regarding key virulence determinants has increased recently but is still somewhat limited. Surface proteins are potential virulence factors and therapeutic targets, and in this study, we decided to target three genes encoding putative membrane lipoproteins in F. tularensis LVS. One of the genes encoded a protein with high homology to the protein family of disulfide oxidoreductases DsbA. The two other genes encoded proteins with homology to the VacJ, a virulence determinant of Shigella flexneri. The gene encoding the DsbA homologue was verified to be required for survival and replication in macrophages and importantly also for in vivo virulence in the mouse infection model for tularemia. Using a combination of classical and shotgun proteome analyses, we were able to identify several proteins that accumulated in fractions enriched for membrane-associated proteins in the dsbA mutant. These proteins are substrate candidates for the DsbA disulfide oxidoreductase as well as being responsible for the virulence attenuation of the dsbA mutant.
- MeSH
- bakteriální proteiny genetika chemie metabolismus MeSH
- buněčné linie MeSH
- chromatografie kapalinová metody MeSH
- faktory virulence genetika chemie metabolismus MeSH
- Francisella tularensis genetika metabolismus patogenita MeSH
- hmotnostní spektrometrie metody MeSH
- isoelektrická fokusace MeSH
- lidé MeSH
- makrofágy cytologie metabolismus MeSH
- membránové proteiny genetika chemie metabolismus MeSH
- míra přežití MeSH
- molekulární sekvence - údaje MeSH
- mutace MeSH
- myši inbrední BALB C MeSH
- myši MeSH
- peptidy genetika chemie metabolismus MeSH
- proteindisulfidisomerasy genetika chemie metabolismus MeSH
- proteom analýza MeSH
- proteomika metody MeSH
- tularemie metabolismus mortalita MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
