The world's first wiki where authorship really matters (Nature Genetics, 2008). Due credit and reputation for authors. Imagine a global collaborative knowledge base for original thoughts. Search thousands of articles and collaborate with scientists around the globe.

wikigene or wiki gene protein drug chemical gene disease author authorship tracking collaborative publishing evolutionary knowledge reputation system wiki2.0 global collaboration genes proteins drugs chemicals diseases compound
Hoffmann, R. A wiki for the life sciences where authorship matters. Nature Genetics (2008)
 
 
 

Cytochrome c-mediated caspase-9 activation triggers apoptosis in Streptococcus pyogenes-infected epithelial cells.

Epithelial cells are the initial sites of host invasion by group A Streptococcus pyogenes (GAS), and their infection of epithelial cells has been suggested to induce apoptosis. However, the mechanism responsible for bacteria-host interaction and the induction of apoptosis has not been clearly understood. We demonstrate here that human pharyngeal epithelial HEp-2 cells became apoptotic with DNA fragmentation by invasion of GAS strains JRS4 (M6+, F1+) and JRS145 (M6-, F1+ mutant of JRS4), whereas apoptotic cellular changes were not observed in SAM1 (M6+, F1- mutant) or SAM2 (M6-, F1- mutant) infected HEp-2 cells. Confocal microscopy revealed that Bax translocation to mitochondria and cytochrome c release occurred after 4 h of infection. Western blot analyses showed that the amounts of Bcl-2 and Bcl-xL were decreased in the mitochondria of infected cells. In addition, we demonstrated that the release of nuclear histone from infected cells was prevented by the addition of caspase-9 inhibitor (Ac-LEHD-CHO). We conclude that the internalization of GAS in epithelial cells is necessary and sufficient for the induction of apoptosis, which is initiated by mitochondrial dysfunction, and the mechanism of GAS-induced apoptosis is clearly different from that induced by other intracellular invasive bacteria, e.g. Shigella and Salmonella species.[1]

References

  1. Cytochrome c-mediated caspase-9 activation triggers apoptosis in Streptococcus pyogenes-infected epithelial cells. Nakagawa, I., Nakata, M., Kawabata, S., Hamada, S. Cell. Microbiol. (2001) [Pubmed]
 
WikiGenes - Universities