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Pneumococcal Pneumolysin Induces DNA Damage and Cell Cycle Arrest.
Prashant Rai1,2, Fang He3, Jimmy Kwang2,3
1Infectious Diseases Group, Singapore-MIT Alliance for Research &Technology, Singapore 138602.
Scientific Reports
|March 31, 2016
Summary
Streptococcus pneumoniae
Area of Science:
- Microbiology
- Molecular Biology
- Cell Biology
Background:
- Streptococcus pneumoniae is a major human pathogen.
- Pneumolysin is a key virulence factor produced by S. pneumoniae.
- Pneumolysin is a cholesterol-dependent cytolysin that forms pores in host cell membranes.
Purpose of the Study:
- To investigate the cytotoxic mechanisms of pneumolysin.
- To determine if pneumolysin induces DNA damage.
- To elucidate the role of pneumolysin in S. pneumoniae pathogenesis.
Main Methods:
- Detection of DNA double strand breaks (DSBs) using γH2AX foci.
- Analysis of DNA damage response proteins (MDC1, 53BP1).
- Assessment of cell cycle arrest and apoptosis.
- Inhibition of DNA repair pathways (non-homologous end joining).
- Neutralization of pneumolysin oligomerization domain.
Main Results:
- Pneumolysin induces DNA double strand breaks (DSBs) in host cells.
- Pneumolysin-induced DSBs recruit DNA damage response proteins.
- Toxin-induced DNA damage precedes cell cycle arrest and apoptosis.
- Cells undergoing DNA replication are more susceptible to pneumolysin-induced DSBs.
- Neutralization of pneumolysin oligomerization suppresses DNA damage and cell cycle arrest.
Conclusions:
- Pneumolysin induces cytotoxicity through DNA damage.
- Pneumolysin oligomerization is critical for inducing DNA damage.
- This study reveals a novel mechanism of pneumolysin-mediated pathogenesis.
- Targeting pneumolysin's DNA-damaging ability could be a therapeutic strategy.
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