Project description:Characterization of the molecular interplay between Moraxella catarrhalis and human respiratory tract epithelial cells: Expression Moraxella catarrhalis strain BBH18 during adherence to human phanryngeal epithelial Detroit 562 cells
Project description:The complement system is an important part of the innate defense against invading pathogens. The ability to resist complement-mediated killing is considered to be an important virulence trait for the human-restricted respiratory tract pathogen M. catarrhalis, as most disease-associated M. catarrhalis isolates are complement-resistant. Here we studied the molecular basis of M. catarrhalis complement-resistance by transcriptome profiling upon exposure to 10% normal human serum (NHS).
Project description:During the course of infection, respiratory pathogens like Moraxella catarrhalis needs to adhere to epithelial cells of different host niches such as the nasopharynx and lungs. Consequently, efficient adhesion to epithelial cells is considered an important virulence trait of M. catarrhalis. We examined the interaction between human pharyngeal epithelial Detroit 562 cells and M. catarrhalis BBH18 during adherence using a combination of Tn-seq, a genome-wide negative selection screenings technology, and expression profiling of both host and pathogen. The results described in this study are further discussed in Stefan P.W. de Vries, Marc J. Eleveld, Peter W.M. Hermans, Hester J. Bootsma: Characterization of the molecular interplay between Moraxella catarrhalis and human respiratory tract epithelial cells, submitted.
Project description:During the course of infection, respiratory pathogens like Moraxella catarrhalis needs to adhere to epithelial cells of different host niches such as the nasopharynx and lungs. Consequently, efficient adhesion to epithelial cells is considered an important virulence trait of M. catarrhalis. We examined the interaction between human pharyngeal epithelial Detroit 562 cells and M. catarrhalis BBH18 during adherence using a combination of Tn-seq, a genome-wide negative selection screenings technology, and expression profiling of both host and pathogen. The results described in this study are further discussed in Stefan P.W. de Vries, Marc J. Eleveld, Peter W.M. Hermans, Hester J. Bootsma: Characterization of the molecular interplay between Moraxella catarrhalis and human respiratory tract epithelial cells, submitted.
Project description:The complement system is an important part of the innate defense against invading pathogens. The ability to resist complement-mediated killing is considered to be an important virulence trait for the human-restricted respiratory tract pathogen M. catarrhalis, as most disease-associated M. catarrhalis isolates are complement-resistant. Here we studied the molecular basis of M. catarrhalis complement-resistance by transcriptome profiling upon exposure to 10% normal human serum (NHS). After 1h exposure of M. catarrhalis BBH18 to 10% NHS (n = 5) or the NHS dilution buffer alone (control, n = 5), total RNA was isolated and labeled cDNA was generated according to standard Nimblegen gene expression array protocols and hybridized to 4x72K Nimblegen M. catarrhalis expression arrays for read-out.
Project description:During the course of infection, respiratory pathogens like Moraxella catarrhalis needs to adhere to epithelial cells of different host niches such as the nasopharynx and lungs. Consequently, efficient adhesion to epithelial cells is considered an important virulence trait of M. catarrhalis. We examined the interaction between human pharyngeal epithelial Detroit 562 cells and M. catarrhalis BBH18 during adherence using a combination of Tn-seq, a genome-wide negative selection screenings technology, and expression profiling of both host and pathogen. The results described in this study are further discussed in Stefan P.W. de Vries, Marc J. Eleveld, Peter W.M. Hermans, Hester J. Bootsma: Characterization of the molecular interplay between Moraxella catarrhalis and human respiratory tract epithelial cells, submitted. RNA was isolated from Detroit cells exposed to culture medium alone (n=6; control), and Detroits cells exposed to adherent M. catarrhalis BBH18 (n=6) using RNeasy columns. Total RNA was labeled according to standard Nimblegen gene expression array protocols and hybridized to a 12x135 Nimblegen human expression array for read-out.
Project description:Background: Moraxella catarrhalis, a major nasopharyngeal pathogen of the human respiratory tract, is exposed to rapid downshifts of environmental temperature when humans breathe cold air. The prevalence of pharyngeal colonization and respiratory tract infections caused by M. catarrhalis is greatest in winter. We investigated how M. catarrhalis uses the physiologic exposure to cold air to regulate pivotal survival systems that may contribute to M. catarrhalis virulence. Results: In this study we used the RNA-seq techniques to quantitatively catalogue the transcriptome of M. catarrhalis exposed to a 26°C cold shock or to continuous growth at 37°C. Validation of RNA-seq data using quantitative RT-PCR analysis demonstrated the RNA-seq results to be highly reliable. We observed that a 26°C cold shock induces the expression of genes that in other bacteria have been related to virulence: a strong induction was observed for genes involved in high affinity phosphate transport and iron acquisition, indicating that M. catarrhalis makes a better use of both phosphate and iron resources after exposure to cold shock. We detected the induction of genes involved in nitrogen metabolism, as well as several outer membrane proteins, including ompA, m35-like porin and multidrug efflux pump (acrAB) indicating that M. catarrhalis remodels its membrane components in response to downshift of temperature. Furthermore, we demonstrate that a 26°C cold shock enhances the induction of genes encoding the type IV pili that are essential for natural transformation, and increases the genetic competence of M. catarrhalis, which may facilitate the rapid spread and acquisition of novel virulence-associated genes.
Project description:During the course of infection, respiratory pathogens like Moraxella catarrhalis needs to adhere to epithelial cells of different host niches such as the nasopharynx and lungs. Consequently, efficient adhesion to epithelial cells is considered an important virulence trait of M. catarrhalis. We examined the interaction between human pharyngeal epithelial Detroit 562 cells and M. catarrhalis BBH18 during adherence using a combination of Tn-seq, a genome-wide negative selection screenings technology, and expression profiling of both host and pathogen. The results described in this study are further discussed in Stefan P.W. de Vries, Marc J. Eleveld, Peter W.M. Hermans, Hester J. Bootsma: Characterization of the molecular interplay between Moraxella catarrhalis and human respiratory tract epithelial cells, submitted. After 1 hour adherence to Detroit 562 cells, RNA was isolated from adherent (n = 4) and non-adherent (planktonic) (n = 4) M. catarrhalis BBH18 as well as from bacteria incubated in the infection medium alone (n = 3). RNA obtained from the adherent fraction was enriched for bacterial RNA using the MICROBEnrich kit (Ambion). Total RNA was labeled according to standard Nimblegen gene expression array protocols and hybridized to a 4x72K Nimblegen M. catarrhalis expression array for read-out.
