TY  - JOUR
A1  - Tegtmeyer, Nicole
A1  - Moodley, Yoshan
A1  - Yamaoka, Yoshio
A1  - Pernitzsch, Sandy Ramona
A1  - Schmidt, Vanessa
A1  - Traverso, Francisco Rivas
A1  - Schmidt, Thomas P.
A1  - Rad, Roland
A1  - Yeoh, Khay Guan
A1  - Bow, Ho
A1  - Torres, Javier
A1  - Gerhard, Markus
A1  - Schneider, Gisbert
A1  - Wessler, Silja
A1  - Backert, Steffen
T1  - Characterisation of worldwide Helicobacter pylori strains reveals genetic conservation and essentiality of serine protease HtrA
JF  - Molecular Microbiology
N2  - HtrA proteases and chaperones exhibit important roles in periplasmic protein quality control and stress responses. The genetic inactivation of htrA has been described for many bacterial pathogens. However, in some cases such as the gastric pathogen Helicobacter pylori, HtrA is secreted where it cleaves the tumour-suppressor E-cadherin interfering with gastric disease development, but the generation of htrA mutants is still lacking. Here, we show that the htrA gene locus is highly conserved in worldwide strains. HtrA presence was confirmed in 992 H.pylori isolates in gastric biopsy material from infected patients. Differential RNA-sequencing (dRNA-seq) indicated that htrA is encoded in an operon with two subsequent genes, HP1020 and HP1021. Genetic mutagenesis and complementation studies revealed that HP1020 and HP1021, but not htrA, can be mutated. In addition, we demonstrate that suppression of HtrA proteolytic activity with a newly developed inhibitor is sufficient to effectively kill H.pylori, but not other bacteria. We show that Helicobacter htrA is an essential bifunctional gene with crucial intracellular and extracellular functions. Thus, we describe here the first microbe in which htrA is an indispensable gene, a situation unique in the bacterial kingdom. HtrA can therefore be considered a promising new target for anti-bacterial therapy.
KW  - Helicobacter pylori
KW  - cag pathogenicity island
KW  - Differential RNA-sequencing
KW  - epithelial cells
KW  - campylobacter jejuni infection
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-190774
VL  - 99
IS  - 5
ER  - 
TY  - JOUR
A1  - Blättner, Sebastian
A1  - Das, Sudip
A1  - Paprotka, Kerstin
A1  - Eilers, Ursula
A1  - Krischke, Markus
A1  - Kretschmer, Dorothee
A1  - Remmele, Christian W.
A1  - Dittrich, Marcus
A1  - Müller, Tobias
A1  - Schuelein-Voelk, Christina
A1  - Hertlein, Tobias
A1  - Mueller, Martin J.
A1  - Huettel, Bruno
A1  - Reinhardt, Richard
A1  - Ohlsen, Knut
A1  - Rudel, Thomas
A1  - Fraunholz, Martin J.
T1  - Staphylococcus aureus Exploits a Non-ribosomal Cyclic Dipeptide to Modulate Survival within Epithelial Cells and Phagocytes
JF  - PLoS Pathogens
N2  - Community-acquired (CA) Staphylococcus aureus cause various diseases even in healthy individuals. Enhanced virulence of CA-strains is partly attributed to increased production of toxins such as phenol-soluble modulins (PSM). The pathogen is internalized efficiently by mammalian host cells and intracellular S. aureus has recently been shown to contribute to disease. Upon internalization, cytotoxic S. aureus strains can disrupt phagosomal membranes and kill host cells in a PSM-dependent manner. However, PSM are not sufficient for these processes. Here we screened for factors required for intracellular S. aureus virulence. We infected escape reporter host cells with strains from an established transposon mutant library and detected phagosomal escape rates using automated microscopy. We thereby, among other factors, identified a non-ribosomal peptide synthetase (NRPS) to be required for efficient phagosomal escape and intracellular survival of S. aureus as well as induction of host cell death. By genetic complementation as well as supplementation with the synthetic NRPS product, the cyclic dipeptide phevalin, wild-type phenotypes were restored. We further demonstrate that the NRPS is contributing to virulence in a mouse pneumonia model. Together, our data illustrate a hitherto unrecognized function of the S. aureus NRPS and its dipeptide product during S. aureus infection.
KW  - cell death
KW  - cytotoxicity
KW  - Staphylococcus aureus
KW  - host cells
KW  - neutrophils
KW  - macrophages
KW  - transposable elements
KW  - epithelial cells
Y1  - 2016
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-180380
VL  - 12
IS  - 9
ER  -