Project description:BACKGROUND: Streptococcus pneumoniae, the pneumococcus, is the main etiological agent of pneumonia. Pneumococcal infection is initiated by bacterial adherence to lung epithelial cells. The exact transcriptional changes occurring in both host and microbe during infection are unknown. Here, we developed a time-resolved infection model of human lung alveolar epithelial cells by S. pneumoniae and assess the resulting transcriptome changes in both organisms simultaneously by using dual RNA-seq. RESULTS: Functional analysis of the time-resolved dual RNA-seq data identifies several features of pneumococcal infection. For instance, we show that the glutathione-dependent reactive oxygen detoxification pathway in epithelial cells is activated by reactive oxygen species produced by S. pneumoniae. Addition of the antioxidant resveratrol during infection abates this response. At the same time, pneumococci activate the competence regulon during co-incubation with lung epithelial cells. By comparing transcriptional changes between wild-type encapsulated and mutant unencapsulated pneumococci, we demonstrate that adherent pneumococci, but not free-floating bacteria, repress innate immune responses in epithelial cells including expression of the chemokine IL-8 and the production of antimicrobial peptides. We also show that pneumococci activate several sugar transporters in response to adherence to epithelial cells and demonstrate that this activation depends on host-derived mucins. CONCLUSIONS: We provide a dual-transcriptomics overview of early pneumococcal infection in a time-resolved manner, providing new insights into host-microbe interactions. To allow easy access to the data by the community, a web-based platform was developed ( http://dualrnaseq.molgenrug.nl ). Further database exploration may expand our understanding of epithelial-pneumococcal interaction, leading to novel antimicrobial strategies.
Project description:Infection of the human host by Streptococcus pneumoniae begins with colonization of the nasopharynx, which is mediated by adherence of bacteria to respiratory epithelium. Several studies have indicated an important role for the pneumococcal capsule in this process. Here, we used microarrays to characterize the in vitro transcriptional response of human nasopharyngeal epithelial Detroit 562 cells to adherence of serotype 2-encapsulated strain D39, serotype 19F-encapsulated strain G54, serotype 4-encapsulated strain TIGR4, and their nonencapsulated derivatives (delta-cps). In total, 322 genes were found to be upregulated in response to adherent pneumococci. Twenty-two genes were commonly induced, including those encoding several cytokines (e.g., IL-1-beta, IL-6), chemokines (e.g., IL-8, CXCL1/2), and transcriptional regulators (e.g., FOS), consistent with an innate immune response mediated by Toll-like receptor signaling. Interestingly, 85% of genes was induced specifically by one or more encapsulated strains, suggestive of a capsule-dependent response. Importantly, purified capsular polysaccharides alone had no effect. Over a third of these loci encoded products predicted to be involved in transcriptional regulation and signal transduction, in particular MAPK signaling pathways. Real-time PCR of a subset of ten genes confirmed microarray data and showed a time-dependent upregulation of especially innate immunity genes. Downregulation of epithelial genes was most pronounced upon adherent D39delta-cps, as 68% of the 161 genes identified was only repressed using this nonencapsulated strain. In conclusion, we identified a subset of host genes specifically induced by encapsulated strains during in vitro adherence, and have demonstrated the complexity of interactions occurring during the initial stages of pneumococcal infection. Experiment Overall Design: We used three different pneumococcal strains and their isogenic nonencapsulated derivatives (delta-cps): serotype 2-encapsulated strain D39, serotype 19F-encapsulated strain G54, and serotype 4-encapsulated strain TIGR4. All experiments were performed in triplicate (3 independent biological replicates) and compared to uninfected control Detroit 562 cells. Bacteria were allowed to adhere to the epithelial cells for 2 hours, after which the transcriptional response of the Detroit cells was analyzed using Affymetrix Human U133 Plus GeneChips. In addition to the 6 strains mentioned above, we included transcriptional analysis of the epithelial cell response to low-dose D39delta-cps (giving adherence equivalent to wild-type D39) and purified type 2 capsular polysaccharides.
Project description:Infection of the human host by Streptococcus pneumoniae begins with colonization of the nasopharynx, which is mediated by adherence of bacteria to respiratory epithelium. Several studies have indicated an important role for the pneumococcal capsule in this process. Here, we used microarrays to characterize the in vitro transcriptional response of human nasopharyngeal epithelial Detroit 562 cells to adherence of serotype 2-encapsulated strain D39, serotype 19F-encapsulated strain G54, serotype 4-encapsulated strain TIGR4, and their nonencapsulated derivatives (Δcps). In total, 322 genes were found to be upregulated in response to adherent pneumococci. Twenty-two genes were commonly induced, including those encoding several cytokines (e.g., IL-1β, IL-6), chemokines (e.g., IL-8, CXCL1/2), and transcriptional regulators (e.g., FOS), consistent with an innate immune response mediated by Toll-like receptor signaling. Interestingly, 85% of genes was induced specifically by one or more encapsulated strains, suggestive of a capsule-dependent response. Importantly, purified capsular polysaccharides alone had no effect. Over a third of these loci encoded products predicted to be involved in transcriptional regulation and signal transduction, in particular MAPK signaling pathways. Real-time PCR of a subset of ten genes confirmed microarray data and showed a time-dependent upregulation of especially innate immunity genes. Downregulation of epithelial genes was most pronounced upon adherent D39Δcps, as 68% of the 161 genes identified was only repressed using this nonencapsulated strain. In conclusion, we identified a subset of host genes specifically induced by encapsulated strains during in vitro adherence, and have demonstrated the complexity of interactions occurring during the initial stages of pneumococcal infection. Keywords: Paired measurements
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.
Project description:Rationale: Respiratory syncytial virus (RSV) and Streptococcus pneumoniae are major respiratory pathogens. Co-infection with RSV and S. pneumoniae is associated with severe and often fatal pneumonia but the molecular basis for this remains unclear. Objectives: To determine if interaction between RSV and pneumococci enhances pneumococcal virulence. Methods: We used confocal microscopy and western blot to identify the receptors involved in direct binding of RSV and pneumococci, the effects of which were studied in both in vivo and in vitro models of infection. Human ciliated respiratory epithelial cell cultures were infected with RSV for 72h and then challenged with pneumococci. Pneumococci were collected after 2h exposure and changes in gene expression determined using qRT-PCR. Results: Following incubation with RSV or purified G protein, pneumococci demonstrated a significant increase in the inflammatory response and bacterial adherence to human ciliated epithelial cultures and markedly increased virulence in a pneumonia model in mice. This was associated with extensive changes in the pneumococcal transcriptome and significant upregulation in the expression of key pneumococcal virulence genes, including the gene for the pneumococcal toxin, pneumolysin. We show that mechanistically this is due to RSV G glycoprotein binding penicillin binding protein 1a. Conclusion: The direct interaction between a respiratory virus protein and the pneumococcus resulting in increased bacterial virulence and worsening disease outcome is a new paradigm in respiratory infection.
Project description:Rationale: Respiratory syncytial virus (RSV) and Streptococcus pneumoniae are major respiratory pathogens. Co-infection with RSV and S. pneumoniae is associated with severe and often fatal pneumonia but the molecular basis for this remains unclear. Objectives: To determine if interaction between RSV and pneumococci enhances pneumococcal virulence. Methods: We used confocal microscopy and western blot to identify the receptors involved in direct binding of RSV and pneumococci, the effects of which were studied in both in vivo and in vitro models of infection. Human ciliated respiratory epithelial cell cultures were infected with RSV for 72h and then challenged with pneumococci. Pneumococci were collected after 2h exposure and changes in gene expression determined using qRT-PCR. Results: Following incubation with RSV or purified G protein, pneumococci demonstrated a significant increase in the inflammatory response and bacterial adherence to human ciliated epithelial cultures and markedly increased virulence in a pneumonia model in mice. This was associated with extensive changes in the pneumococcal transcriptome and significant upregulation in the expression of key pneumococcal virulence genes, including the gene for the pneumococcal toxin, pneumolysin. We show that mechanistically this is due to RSV G glycoprotein binding penicillin binding protein 1a. Conclusion: The direct interaction between a respiratory virus protein and the pneumococcus resulting in increased bacterial virulence and worsening disease outcome is a new paradigm in respiratory infection.
Project description:The columnar epithelial cells comprising the intestinal tract, stomach, and uterus can be cultured in vitro as organoids or in adherent culture. However, the proliferation of these columnar epithelial cells in adherent culture is limited. Likewise, human pluripotent stem cell (hPSC)-derived intestinal epithelial cells do not show extensive or clonal propagation in vitro. In this study, we induced proliferation of hPSC-derived small intestinal epithelium for a longer time by utilizing mesenchymal stromal cells derived from self-organized intestinal organoids as feeders. The proliferating cells exhibited columnar form, microvilli and glycocalyx formation, and cell polarity, as well as expression of drug-metabolizing enzymes and transporters. It is noteworthy that small intestinal epithelial stem cells cannot be cultured in adherent culture alone, and the stromal cells cannot be replaced by other feeders. Organoid-derived mesenchymal stromal cells resemble the trophocytes essential for maintaining small intestinal epithelial stem cells and play a crucial role in adherent culture. The high proliferative expansion, productivity, and functionality of hPSC-derived small intestinal epithelial stem cells could have potential applications in pharmacokinetic and toxicity studies and regenerative medicine.
Project description:Rationale: Respiratory syncytial virus (RSV) and Streptococcus pneumoniae are major respiratory pathogens. Co-infection with RSV and S. pneumoniae is associated with severe and often fatal pneumonia but the molecular basis for this remains unclear. Objectives: To determine if interaction between RSV and pneumococci enhances pneumococcal virulence. Methods: We used confocal microscopy and western blot to identify the receptors involved in direct binding of RSV and pneumococci, the effects of which were studied in both in vivo and in vitro models of infection. Human ciliated respiratory epithelial cell cultures were infected with RSV for 72h and then challenged with pneumococci. Pneumococci were collected after 2h exposure and changes in gene expression determined using qRT-PCR. Results: Following incubation with RSV or purified G protein, pneumococci demonstrated a significant increase in the inflammatory response and bacterial adherence to human ciliated epithelial cultures and markedly increased virulence in a pneumonia model in mice. This was associated with extensive changes in the pneumococcal transcriptome and significant upregulation in the expression of key pneumococcal virulence genes, including the gene for the pneumococcal toxin, pneumolysin. We show that mechanistically this is due to RSV G glycoprotein binding penicillin binding protein 1a. Conclusion: The direct interaction between a respiratory virus protein and the pneumococcus resulting in increased bacterial virulence and worsening disease outcome is a new paradigm in respiratory infection. Comparison of the Streptococcus pneumoniae D39 RSV treated compared to BSA Treated in BEBM medium One condition design comparision of two strains including a dye swap
Project description:Rationale: Respiratory syncytial virus (RSV) and Streptococcus pneumoniae are major respiratory pathogens. Co-infection with RSV and S. pneumoniae is associated with severe and often fatal pneumonia but the molecular basis for this remains unclear. Objectives: To determine if interaction between RSV and pneumococci enhances pneumococcal virulence. Methods: We used confocal microscopy and western blot to identify the receptors involved in direct binding of RSV and pneumococci, the effects of which were studied in both in vivo and in vitro models of infection. Human ciliated respiratory epithelial cell cultures were infected with RSV for 72h and then challenged with pneumococci. Pneumococci were collected after 2h exposure and changes in gene expression determined using qRT-PCR. Results: Following incubation with RSV or purified G protein, pneumococci demonstrated a significant increase in the inflammatory response and bacterial adherence to human ciliated epithelial cultures and markedly increased virulence in a pneumonia model in mice. This was associated with extensive changes in the pneumococcal transcriptome and significant upregulation in the expression of key pneumococcal virulence genes, including the gene for the pneumococcal toxin, pneumolysin. We show that mechanistically this is due to RSV G glycoprotein binding penicillin binding protein 1a. Conclusion: The direct interaction between a respiratory virus protein and the pneumococcus resulting in increased bacterial virulence and worsening disease outcome is a new paradigm in respiratory infection. Comparison of the Streptococcus pneumoniae D39 Protein P treated compared to Protein GTreated in BEBM medium One condition design comparision of two strains including a dye swap
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.