Petra Dersch

University of Münster | WWU · Institute of Infectiology

Enterohemorrhagic Escherichia coli causes watery to bloody diarrhea, which may progress to hemorrhagic colitis and hemolytic-uremic syndrome. While early studies suggested that antibiotic treatment may worsen the pathology of an enterohemorrhagic Escherichia coli (EHEC) infection, recent work has shown that certain non-Shiga toxin-inducing antibiot...

RNA degradation is an essential process that allows bacteria to regulate gene expression and has emerged as an important mechanism for controlling virulence. However, the individual contributions of RNases in this process are mostly unknown. Here, we report that of 11 tested potential RNases of the intestinal pathogen Yersinia pseudotuberculosis ,...

Enterohemorrhagic E. coli causes watery to bloody diarrhea, which may progress to hemorrhagic colitis and hemolytic-uremic syndrome. While early studies suggested that antibiotic treatment may worsen the pathology of an EHEC infection, recent work has shown that certain non-Shiga toxin-inducing antibiotics avert disease progression. Unfortunately,...

Polymicrobial infections involving various combinations of microorganisms, such as Escherichia, Pseudomonas, or Yersinia, can lead to acute and chronic diseases in for example the gastrointestinal and respiratory tracts. Our aim is to modulate microbial communities by targeting the posttranscriptional regulator system called carbon storage regulato...

Yersinia pathogenicity depends mainly on a Type III Secretion System (T3SS) responsible for translocating effector proteins into the eukaryotic target cell cytosol. The T3SS is encoded on a 70 kb, low copy number virulence plasmid, pYV. A key T3SS regulator, YopD, is a multifunctional protein and consists of discrete modular domains that are essent...

Integrins are important cell surface receptors named cell adhesion molecules that mediate cell–cell, cell–matrix, and cell–pathogen interactions. Integrins exist as obligate heterodimers of integral transmembrane α and β subunits linking the extracellular matrix to the intracellular cytoskeleton. In mammals, they are composed of eighteen α subunits...

Mitosis induces cellular rearrangements like spindle formation, Golgi fragmentation, and nuclear envelope breakdown. Similar to certain retroviruses, nuclear delivery during entry of human papillomavirus (HPV) genomes is facilitated by mitosis, during which minor capsid protein L2 tethers viral DNA to mitotic chromosomes. However, the mechanism of...

Background Acute myeloid leukemia (AML) is a fatal clonal hematopoietic malignancy, which results from the accumulation of several genetic aberrations in myeloid progenitor cells, with a worldwide 5-year survival prognosis of about 30%. Therefore, the development of more effective therapeutics with novel mode of action is urgently demanded. One com...

The type III secretion system (T3SS) is indispensable for successful host cell infection by many Gram-negative pathogens. The molecular syringe delivers effector proteins that suppress the host immune response. Synthesis of T3SS components in Yersinia pseudotuberculosis relies on host body temperature, which induces the RNA thermometer (RNAT)-contr...

The small arginine-rich protein protamine condenses complete genomic DNA into the sperm head. Here, we applied its high RNA binding capacity for spontaneous electrostatic assembly of therapeutic nanoparticles decorated with tumour-cell-specific antibodies for efficiently targeting siRNA. Fluorescence microscopy and DLS measurements of these nanocar...

The cytotoxic necrotizing factors (CNFs) are a family of Rho GTPase-activating single-chain exotoxins that are produced by several Gram-negative pathogenic bacteria. Due to the pleiotropic activities of the targeted Rho GTPases, the CNFs trigger multiple signaling pathways and host cell processes with diverse functional consequences. They influence...

Infections with enteropathogenic E. coli (EPEC) cause severe diarrhea in children. The non-invasive bacteria adhere to enterocytes of the small intestine and use a type III secretion system (T3SS) to inject effector proteins into host cells to modify and exploit cellular processes in favor of bacterial survival and replication. Several studies have...

Many bacterial pathogens use a type III secretion system (T3SS) as molecular syringe to inject effector proteins into the host cell. In the foodborne pathogen Yersinia pseudotuberculosis , delivery of the secreted effector protein cocktail through the T3SS depends on YopN, a molecular gatekeeper that controls access to the secretion channel from th...

Tyrosine kinase inhibitors have significantly improved treatment of patients with different malignancies, but their utilization can be compromised by unintended toxicities. Ibrutinib is a first-in-class covalent inhibitor of the Bruton´s tyrosine kinase inhibitor that has been approved for the treatment of patients with chronic lymphocytic leukemia...

Ibrutinib is an inhibitor of Bruton's tyrosine kinase that has been approved for the treatment of patients with chronic lymphocytic leukemia, mantle cell lymphoma and Waldenstrom's macroglobulinemia and is connected with toxicities. To minimize its toxicities, we linked ibrutinib to a cell‐targeted, internalizing antibody. To this end, we synthesiz...

Virulence gene expression of Yersinia pseudotuberculosis changes during the different stages of infection and this is tightly controlled by environmental cues. In this study, we show that the small protein YmoA, a member of the Hha family, is part of this process. It controls temperature- and nutrient-dependent early and later stage virulence genes...

Endocytosis of extracellular or plasma membrane material is a fundamental process. A variety of endocytic pathways exist, several of which are barely understood in terms of mechanistic execution and biological function. Importantly, some mechanisms have been identified and characterized by following virus internalization into cells. This includes a...

Many bacterial pathogens use a type III secretion system (T3SS) as molecular syringe to inject effector proteins into the host cell. In the foodborne pathogen Yersinia pseudotuberculosis, delivery of the secreted effector protein cocktail through the T3SS depends on YopN, a molecular gatekeeper that controls access to the secretion channel from the...

Infections with enteropathogenic E. coli (EPEC) cause severe diarrhea in children. The non-invasive bacteria adhere to enterocytes of the small intestine and use a type III secretion system (T3SS) to inject effector proteins into host cells to modify and exploit cellular processes in favor of bacterial survival and replication. Several studies have...

Much of our current knowledge about cellular RNA-protein complexes in bacteria is derived from analyses in gram-negative model organisms, with the discovery of RNA-binding proteins (RBPs) generally lagging behind in gram-positive species. Here, we have applied Grad-seq analysis of native RNA-protein complexes to a major gram-positive human pathogen...

Outer membrane vesicles (OMVs), nanoparticles released by Shiga toxin-producing Escherichia coli (STEC), have been identified as novel efficient virulence tools of these pathogens. STEC O157 OMVs carry a cocktail of virulence factors including Shiga toxin 2a (Stx2a), cytolethal distending toxin V (CdtV), EHEC hemolysin, flagellin, and lipopolysacch...

Whereas the O104:H4 enterohemorrhagic Escherichia coli (EHEC) outbreak strain from 2011 expresses aggregative adherence fimbriae of subtype I (AAF/I), its close relative, the O104:H4 enteroaggregative Escherichia coli (EAEC) strain 55989, encodes AAF of subtype III. Tight adherence mediated by AAF/I in combination with Shiga toxin 2 production has...

Cytotoxic necrotizing factors (CNFs) are bacterial single-chain exotoxins that modulate cytokinetic/oncogenic and inflammatory processes through activation of host cell Rho GTPases. To achieve this, they are secreted, bind surface receptors to induce endocytosis and translocate a catalytic unit into the cytosol to intoxicate host cells. A three-dim...

Enteropathogenic Yersiniae evolved a plethora of virulence traits which allow them to colonize the intestine and gut-associated lymphatic tissues of mammals. In these host niches they have to tightly adjust the expression of required pathogenicity factors to resist attacks by the host immune system. Here, we present how enteric Yersiniae use intric...

Type VI secretion systems (T6SSs) are complex macromolecular injection machines which are widespread in Gram-negative bacteria. They are involved in host-cell interactions and pathogenesis, required to eliminate competing bacteria, or are important for the adaptation to environmental stress conditions. Here we identified regulatory elements control...

The dynamic conformation of RNA molecules within living cells is key to their function. Recent advances in probing the RNA structurome in vivo, including the use of SHAPE (Selective 2'-Hydroxyl Acylation analyzed by Primer Extension) or kethoxal reagents or DMS (dimethyl sulfate), provided unprecedented insights into the architecture of RNA molecul...

Infections with Shiga toxin-producing Escherichia coli (STEC) cause outbreaks of severe diarrheal disease in children and the elderly around the world. The severe complications associated with toxin production and release range from bloody diarrhea and hemorrhagic colitis to hemolytic-uremic syndrome, kidney failure, and neurological issues. As the...

Cytotoxic necrotizing factors (CNFs) are single-chain exotoxins. They are secreted by several bacterial pathogens to modulate cytokinetic/oncogenic and inflammatory processes through activation host cell Rho-GTPases, but their secretion-translocation mechanism still remains an enigma. Here, we determined the crystal structure of full-length Yersini...

Infections with enterohemorrhagic Escherichia coli (EHEC) cause disease ranging from mild diarrhea to hemolytic uremic syndrome (HUS) and are the most common cause of renal failure in children in high income countries. The severity of the disease derives from the release of Shiga toxins (Stx). The use of antibiotics to treat EHEC infections is gene...

The composition of the intestinal microbiota influences the outcome of enteric infections in human and mice. However, the role of specific members and their metabolites contributing to disease severity is largely unknown. Using isogenic mouse lines harboring distinct microbiota communities, we observed highly variable disease kinetics of enteric Ci...

Oral administration is a preferred model for studying infection by bacterial enteropathogens such as Yersinia . In the mouse model, the most frequent method for oral infection consists of oral gavage with a feeding needle directly introduced in the animal stomach via the esophagus. In this study, we compared needle gavage to bread feeding as an alt...

Bacillus subtilis cells are well suited to study how bacteria sense and adapt to proteotoxic stress such as heat, since temperature fluctuations are a major challenge to soil-dwelling bacteria. Here, we show that the alarmones (p)ppGpp, well known second messengers of nutrient starvation, are also involved in the heat stress response as well as the...

Frequent transitions of bacterial pathogens between their warm-blooded host and external reservoirs are accompanied by abrupt temperature shifts. A temperature of 37°C serves as reliable signal for ingestion by a mammalian host, which induces a major reprogramming of bacterial gene expression and metabolism. Enteric Yersiniae are Gram-negative path...

Oral administration is a preferred model for studying infection by bacterial enteropathogens such as Yersinia . In the mouse model, the most frequent method for oral infection consists of oral gavage with a feeding needle directly introduced in the animal stomach via the esophagus. In this study, we compared needle gavage to bread feeding as an alt...

Here, B. subtilis was used as a model organism to investigate how cells respond and adapt to proteotoxic stress conditions. Our experiments suggested that the stringent response, caused by raised levels of the (p)ppGpp alarmone, plays a role during thermotolerance development and the heat shock response. Accordingly, our experiments revealed a rapi...

Type III secretion systems (T3SSs) are utilized by numerous Gram-negative bacteria to efficiently interact with host cells and manipulate their function. Appropriate expression of type III secretion genes is achieved through the integration of multiple control elements and regulatory pathways that ultimately coordinate the activity of a central tra...

Numerous Gram-negative pathogens use a Type III Secretion System (T3SS) to promote virulence by injecting effector proteins into targeted host cells, which subvert host cell processes. Expression of T3SS and the effectors is triggered upon host cell contact, but the underlying mechanism is poorly understood. Here, we report a novel strategy of Yers...

A detailed knowledge about virulence-relevant genes, as well as where and when they are expressed during the course of an infection is required to obtain a comprehensive understanding of the complex host–pathogen interactions. The development of unbiased probe-independent RNA sequencing (RNA-seq) approaches has dramatically changed transcriptomics....

Recent studies revealed an amazing phenotypic heterogeneity between genetically identical individual cells within populations of microbial pathogens. During the course of an infection, subpopulations occur, which differ in certain virulence-relevant factors, stress adaptation functions or physiological and metabolic abilities. The mechanisms drivin...

Yersinia enterocolitica is a major diarrheal pathogen and is associated with a large range of gut-associated diseases. Members of this species have evolved into different phylogroups with genotypic variations. We performed the first characterization of the Y. enterocolitica transcriptional landscape and tracked the consequences of the genomic varia...

The Cpx-envelope stress system regulates the expression of virulence factors in many Gram-negative pathogens. In Salmonella enterica serovar Typhimurium deletion of the sensor kinase CpxA but not of the response regulator CpxR results in the down regulation of the key regulator for invasion, HilA encoded by the Salmonella pathogenicity island 1 (SP...

The carbon storage regulator A (CsrA) is a conserved global regulatory system known to control central carbon pathways, biofilm formation, motility, and pathogenicity. The aim of this study was to characterize changes in major metabolic pathways induced by CsrA in human enteropathogenic Escherichia coli (EPEC) grown under virulence factor-inducing...

Clostron-based knock out of the Clostridioides difficile fur gene. On the left side the mutagenesis strategy and the theoretical PCR-based control with all necessary primers and resulting PCR products are depicted. Corresponding primers and test condition are outlined in the method section. On the right side an experimental PCR-based verification o...

Complementation of the fur mutant with fur in trans. Growth on high iron containing minimal medium of C. difficile wild type (black), the corresponding fur mutant (green), and the fur mutant complemented in trans with the fur gene (red) was monitored by absorbance measurements at 600 nm (left, in absorbance units) over the time period indicated (bo...

Principle component analysis (PCA) of the RNA-Seq based transcriptome samples from this study in biological triplicates. Cultures were grown in CDM medium under high (760 μg/l) and low (11 μg/l) iron conditions, harvested at mid-log phase (see Figure 1) and used for transcriptome (RNA-Seq) analyses. Obtained results were used for PCA. Orange circle...

Growth of wild type and fur mutant C. difficile in BHI medium. C. difficile 630Δerm and corresponding fur mutant were grown in BHI medium for 24 h. Growth in anaerobic flasks was monitored every 2 h in at least 3 independent cultivations by measuring the optical density of the culture at 600 nm. The black curve represents 630Δerm growth and the gre...

Comparative transcriptome (RNA-Seq) analysis of C. difficile wild type grown at high iron versus the fur mutant at high iron conditions. For details, please consult the Section “Materials and Methods” and “Results.”

Comparative metabolome and exo-metabolome analysis of C. difficile wild type and the fur mutant grown at low and high iron conditions. For details, please consult the Section “Materials and Methods” and “Results”.

Comparison of the growth behavior of C. difficile wild type (black) and the corresponding fur mutant strain (green) utilizing different iron sources. C. difficile 630Δerm and the corresponding fur mutant were grown for 24 h in CDM medium with different iron sources. The iron sources were: FeSO4 (A), Fe citrate (B), hemin (C), FeCl3 (D), transferrin...

Genome annotation conversion table for the C. difficile 630 (lane A) and C. difficile 630Δerm (B). Given is further the gene name (lane C), the start point (D) and end point (E) on the genome, the coding strand (F), the Refseq No. (G), the EC No. of the encoded enzyme (H), the TIGR main role (I), the TIGR minor role (J), the GO terms (K), the name...

Comparative transcriptome (RNA-Seq) analysis of C. difficile wild type grown at low and high iron conditions. For details, please consult the Section “Materials and Methods” and “Results”.

Comparative transcriptome (RNA-Seq) analysis of the C. difficile fur mutant grown at low and high iron conditions. For details, please consult the Section “Materials and Methods” and “Results”.

Comparative proteome analysis of C. difficile wild type and the fur mutant grown at low and high iron conditions. For details, please consult the Section “Materials and Methods and “Results.”

Bioinformatics-based investigation of the Fur-binding sites in the C. difficile 630Δerm genome. Listed are all found Fur binding sites found with the consensus shown in Figure 2 upstream from the indicated genes/operons. The results for the Fur binding sites described by Dubois et al. (2016) and from Ho and Ellermeier (2015) are included. For detai...

Iron-binding proteins in C. difficile. Locus tags of Clostridioides difficile 630Δerm and their annotation and bound iron as detected by InterPro Scan. Green highlighted locus tags were found regulated in the present experimental set-up (see Table 1).

The Gram-negative enteropathogen Yersinia pseudotuberculosis possesses a number of regulatory systems that detect cell envelope damage caused by noxious extracytoplasmic stresses. The CpxA sensor kinase and CpxR response regulator two-component regulatory system is one such pathway. Active Cpx signalling upregulates various factors designed to repa...

Purpose The objective of this work was to evaluate the potential of polymeric spherical and aspherical invasive nanocarriers, loaded with antibiotic, to access and treat intracellular bacterial infections. Methods Aspherical nanocarriers were prepared by stretching of spherical precursors, and both aspherical and spherical nanocarriers were surfac...

Adaptive immunity is essentially required to control acute infection with enteropathogenic Yersinia pseudotuberculosis (Yptb). We have recently demonstrated that Yptb can directly modulate naïve CD4⁺ T cell differentiation. However, whether fully differentiated forkhead box protein P3 (Foxp3⁺) regulatory T cells (Tregs), fundamental key players to...

A large German outbreak in 2011 was caused by a locus of enterocyte effacement (LEE)-negative enterohemorrhagic E. coli (EHEC) strain of the serotype O104:H4. This strain harbors markers that are characteristic of both EHEC and enteroaggregative E. coli (EAEC), including aggregative adhesion fimbriae (AAF) genes. Such rare EHEC/EAEC hybrids are hig...

The response to iron limitation of several bacteria is regulated by the ferric uptake regulator (Fur). The Fur-regulated transcriptional, translational and metabolic networks of the Gram-positive, pathogen Clostridioides difficile were investigated by a combined RNA sequencing, proteomic, metabolomic and electron microscopy approach. At high iron c...

The genus Yersinia includes three human pathogenic species, Yersinia pestis, the causative agent of the bubonic and pneumonic plague, and enteric pathogens Y. enterocolitica and Y. pseudotuberculosis that cause a number of gut-associated diseases. Over the past years a large repertoire of RNA-based regulatory systems has been discovered in these pa...

Gut-draining mesenteric lymph nodes (mLNs) are important for inducing peripheral tolerance towards food and commensal antigens by providing an optimal microenvironment for de novo generation of Foxp3+ regulatory T cells (Tregs). We previously identified microbiota-imprinted mLN stromal cells as a critical component in tolerance induction. Here we s...

Clostridioides difficile is the major pathogen causing diarrhea following antibiotic treatment. It is considered to be a strictly anaerobic bacterium, however, previous studies have shown a certain and strain-dependent oxygen tolerance. In this study, the model strain C. difficile 630Δerm was shifted to micro-aerobiosis and was found to stay growin...

Yersinia pseudotuberculosis is a Gram-negative bacterium and zoonotic pathogen responsible for a wide range of diseases, ranging from mild diarrhea, enterocolitis, lymphatic adenitis to persistent local inflammation. TheY. pseudotuberculosisinvasin D (InvD) molecule belongs to the invasin (InvA)-type autotransporter proteins, but its structure and...

Author summary A complex cascade of events is triggered by the mammalian host upon a bacterial infection to prevent pathogen-induced damage. Many pathogens are successfully eliminated by the host immune system. However, some bacterial pathogens, including enteric yersiniae, evolved strategies to efficiently evade immune surveillance. This enables t...

Growing knowledge of the complexity of the host-pathogen interactions during the course of an infection revealed an amazing variability of bacterial pathogens within the same host tissue site. This heterogeneity in bacterial populations is either the result of a different bacterial response to a slightly divergent tissue microenvironment or is caus...

Tissue RNA-Seq work flow and RNA isolation of Yersinia-infected ceca. (A) Host transcriptome assessment workflow of ceca from Y. pseudotuberculosis YPIII and YPIII ΔcnfY-infected mice or equally aged uninfected mice. Total RNA was isolated from the ceca of mice, processed for preparation of strand-specific barcoded cDNA libraries and sequenced. cDN...

Host transcriptional changes upon a wildtype and ΔcnfY mutant infection. Volcano plots obtained from DESeq2 analysis of uninfected and infected cecal RNA pools obtained from acute (A) and persistently (B) infected mice. (TIF)

Global gene expression changes within BALB/c mice (DESeq2 analysis cecum uninfected vs. YPIII infected at 42 dpi). (XLS)

Analysis of growth, virulence and persistence of mRuby2-expressing Y. pseudotuberculosis. (A) YPIII or YP147(ΔcnfY) mRuby2 expressing isogenic strains were grown at 25°C and 37°C in LB medium. At indicated time points, optical density at 600 nm was determined. The data show the mean +/- SEM of three independent experiments performed in duplicates....

RNA-seq data reproducibility between replicates. RPKM normalized read counts for all detected mouse genes of uninfected, YPIII- and YP147(ΔcnfY)-infected mice during acute and persistent infection stage are plotted for all the biological replicates. The Pearson correlation coefficient (r) is given for each replicate. (TIF)

Expression pattern of persistence-relevant Yersinia genes. Relative changes in transcript abundance of selected fitness-relevant Yersinia genes were determined from RNA isolated from (A) YPIII- or YP147(ΔcnfY)-infected ceca 5 and 42 dpi, or (B) from bacteria grown in vitro at 25°C and 37°C. qRT-PCR was performed in four technical replicates. Bacter...

Mapping statistics of RNA-seq libraries. (DOCX)

RNA-seq platform performance. (A-B) ERCC RNA Spike-In Control mix analysis to determine the platform performance. (A) Platform dynamic range and lower limit of detection (LLD) (dose response). Either ERCC ExFold RNA Spike-In Mix 1 or Mix 2 was added to RNA pools obtained from infected and uninfected cecal lymphoid tissue. Column 1, 2 and 3 represen...

Global gene expression changes within BALB/c mice (DESeq2 analysis cecum YPIII vs YP147 (ΔcnfY) at 5 dpi). (XLS)

Global gene expression changes within BALB/c mice (DESeq2 analysis cecum uninfected vs. YP147 (ΔcnfY) at 42 dpi). (XLS)

Histopathology score of YPIII and YP147(ΔcnfY) infected cecal tissue. The inflammation score of H&E stained sections of the cecal lamina propria (A) and the cecal lymphoid tissue (B) of uninfected and infected BALB/c mice at 3 or 42 dpi with about 105−106 CFUs of YPIII or YP147(ΔcnfY)/g tissue. The data show the median scores of 5 mice and were sta...

Fecal microbiota in wildtype- and ΔcnfY mutant-infected mice. At indicated time points prior (-1) and post infection, feces was sampled from individual mice and tested for Y. pseudotuberculosis. The microbiota composition was analyzed by 16S rRNA gene sequencing and permutational multivariate analysis of variance (ADONIS) was used to calculate the...

Strains, plasmids and primers. (DOCX)

Global gene expression changes within BALB/c mice (DESeq2 analysis cecum uninfected vs. YPIII infected at 5 dpi). (XLS)

Host processes regulated during acute infection with Y. pseudotuberculosis (5 dpi). (DOCX)

Global gene expression changes within BALB/c mice (DESeq2 analysis cecum uninfected vs. YP147 (ΔcnfY) at 5 dpi). (XLS)

Global gene expression changes within BALB/c mice (DESeq2 analysis cecum YP147 (ΔcnfY) vs. YPIII at 42 dpi). (XLS)