TY  - JOUR
A1  - Alzheimer, Mona
A1  - Svensson, Sarah L.
A1  - König, Fabian
A1  - Schweinlin, Matthias
A1  - Metzger, Marco
A1  - Walles, Heike
A1  - Sharma, Cynthia M.
T1  - A three-dimensional intestinal tissue model reveals factors and small regulatory RNAs important for colonization with Campylobacter jejuni
JF  - PLoS Pathogens
N2  - The Gram-negative Epsilonproteobacterium Campylobacter jejuni is currently the most prevalent bacterial foodborne pathogen. Like for many other human pathogens, infection studies with C. jejuni mainly employ artificial animal or cell culture models that can be limited in their ability to reflect the in-vivo environment within the human host. Here, we report the development and application of a human three-dimensional (3D) infection model based on tissue engineering to study host-pathogen interactions. Our intestinal 3D tissue model is built on a decellularized extracellular matrix scaffold, which is reseeded with human Caco-2 cells. Dynamic culture conditions enable the formation of a polarized mucosal epithelial barrier reminiscent of the 3D microarchitecture of the human small intestine. Infection with C. jejuni demonstrates that the 3D tissue model can reveal isolate-dependent colonization and barrier disruption phenotypes accompanied by perturbed localization of cell-cell junctions. Pathogenesis-related phenotypes of C. jejuni mutant strains in the 3D model deviated from those obtained with 2D-monolayers, but recapitulated phenotypes previously observed in animal models. Moreover, we demonstrate the involvement of a small regulatory RNA pair, CJnc180/190, during infections and observe different phenotypes of CJnc180/190 mutant strains in 2D vs. 3D infection models. Hereby, the CJnc190 sRNA exerts its pathogenic influence, at least in part, via repression of PtmG, which is involved in flagellin modification. Our results suggest that the Caco-2 cell-based 3D tissue model is a valuable and biologically relevant tool between in-vitro and in-vivo infection models to study virulence of C. jejuni and other gastrointestinal pathogens.
KW  - in vitro
KW  - stem cells
KW  - invasion
KW  - host
KW  - adhesion
KW  - epithelial cells
KW  - translocation
KW  - virulence
KW  - responses
KW  - microenvironment
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-229454
VL  - 16
IS  - 2
ER  - 
TY  - JOUR
A1  - Esken, Jens
A1  - Goris, Tobias
A1  - Gadkari, Jennifer
A1  - Bischler, Thorsten
A1  - Förstner, Konrad U.
A1  - Sharma, Cynthia M.
A1  - Diekert, Gabriele
A1  - Schubert, Torsten
T1  - Tetrachloroethene respiration in Sulfurospirillum species is regulated by a two‐component system as unraveled by comparative genomics, transcriptomics, and regulator binding studies
JF  - MicrobiologyOpen
N2  - Energy conservation via organohalide respiration (OHR) in dehalogenating Sulfurospirillum species is an inducible process. However, the gene products involved in tetrachloroethene (PCE) sensing and signal transduction have not been unambiguously identified. Here, genome sequencing of Sulfurospirillum strains defective in PCE respiration and comparative genomics, which included the PCE‐respiring representatives of the genus, uncovered the genetic inactivation of a two‐component system (TCS) in the OHR gene region of the natural mutants. The assumption that the TCS gene products serve as a PCE sensor that initiates gene transcription was supported by the constitutive low‐level expression of the TCS operon in fumarate‐adapted cells of Sulfurospirillum multivorans. Via RNA sequencing, eight transcriptional units were identified in the OHR gene region, which includes the TCS operon, the PCE reductive dehalogenase operon, the gene cluster for norcobamide biosynthesis, and putative accessory genes with unknown functions. The OmpR‐family response regulator (RR) encoded in the TCS operon was functionally characterized by promoter‐binding assays. The RR bound a cis‐regulatory element that contained a consensus sequence of a direct repeat (CTATW) separated by 17 bp. Its location either overlapping the −35 box or 50 bp further upstream indicated different regulatory mechanisms. Sequence variations in the regulator binding sites identified in the OHR gene region were in accordance with differences in the transcript levels of the respective gene clusters forming the PCE regulon. The results indicate the presence of a fine‐tuned regulatory network controlling PCE metabolism in dehalogenating Sulfurospirillum species, a group of metabolically versatile organohalide‐respiring bacteria.
KW  - genomics
KW  - organohalide respiration
KW  - RNA sequencing
KW  - tetrachloroethene
KW  - transcriptomics
KW  - two‐component system
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-225754
VL  - 9
IS  - 12
ER  -