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A Fast and Reliable Pipeline for Bacterial Transcriptome Analysis Case study: Serine-dependent Gene Regulation in Streptococcus pneumoniae
Published on: April 25, 2015
Microarray analysis of Streptococcus pneumoniae gene expression changes to human lung epithelial cells
Xin-Ming Song1, Wayne Connor, Shakiba Jalal
1Vaccine and Infectious Disease Organization (VIDO), University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N5E3, Canada. xinming.song@usask.ca
Abstract:
Streptococcus pneumoniae infection starts from the respiratory tract where interaction with host epithelial cells occurs. To gain more insights on pneumococcal pathogenesis, an oligonucleotide (oligo)-based microarray was used to investigate gene expression changes of one serotype 3 encapsulated pathogenic S. pneumoniae strain 82 and one unencapsulated avirulent S. pneumoniae strain R6 upon exposure to human lung epithelial cells (A549) for 1 and 3 h, respectively. We observed that genes associated with many functional categories were differentially regulated in strain 82, such as genes in pathogenesis, cell envelope, transcription, translation, transport, metabolism, and unknown functions. In contrast, few genes were changed in strain R6 except for genes in ribonucleotide biosynthesis and unknown functions. Quantitative real-time PCR analysis confirmed the microarray results for most of the genes tested. To further characterize functions of the selected genes, knockout mutants were constructed in strain R6. We demonstrated that 2 genetic loci, SP_2170 (AdcB, zinc ABC transporter) and SP_0157 (hypothetical protein), were involved in adherence to A549 cells. These data suggest that divergent gene expression changes occur in S. pneumoniae pathogenic and avirulent strains during interaction with human lung epithelial cells. Some of those genes are involved in pneumococcal pathogenesis.
Insights
Pathogenic Streptococcus pneumoniae showed significant gene expression changes in lung epithelial cells, unlike avirulent strains. Specific genes were identified that influence bacterial adherence, offering insights into pneumococcal pathogenesis.
Area of Science:
- Microbiology
- Molecular Biology
- Infectious Diseases
Background:
- Streptococcus pneumoniae initiates infection in the respiratory tract, interacting with host epithelial cells.
- Understanding pneumococcal pathogenesis requires investigating bacterial gene expression during host cell interaction.
Purpose of the Study:
- To compare gene expression profiles of pathogenic and avirulent S. pneumoniae strains upon interaction with human lung epithelial cells.
- To identify specific genes involved in bacterial adherence and pathogenesis.
Main Methods:
- Oligonucleotide (oligo)-based microarray analysis was employed to assess gene expression changes.
- Quantitative real-time PCR (qRT-PCR) was used to validate microarray findings.
- Knockout mutants were constructed in an avirulent strain to determine gene function.
Main Results:
- The encapsulated pathogenic strain (serotype 3, strain 82) exhibited differential regulation in numerous functional categories, including pathogenesis and metabolism.
- The unencapsulated avirulent strain (strain R6) showed minimal gene expression changes, primarily in ribonucleotide biosynthesis.
- Two genetic loci, SP_2170 (AdcB, zinc ABC transporter) and SP_0157 (hypothetical protein), were identified as crucial for adherence to A549 lung epithelial cells.
Conclusions:
- Significant divergence in gene expression exists between pathogenic and avirulent S. pneumoniae strains during host cell interaction.
- Specific identified genes, like SP_2170 and SP_0157, play a role in pneumococcal adherence and contribute to pathogenesis.
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