Porphyromonas gingivalis Fimbriae Inhibit Caspase-3-Mediated Apoptosis of Monocytic THP-1 Cells under Growth Factor Deprivation via Extracellular Signal-Regulated Kinase-Dependent Expression of p21 Cip/WAF1

AUTOR(ES)

Ozaki, Ken

FONTE

American Society for Microbiology

RESUMO

Apoptotic regulation of monocytes/macrophages appears to be closely associated with chronic inflammatory reactions. Since it was demonstrated earlier that certain bacterial cell components are involved in apoptotic regulation of these cells, in the present study, we investigated whether the bacterial fimbria, an important cell structure involved in bacterial adherence to host cells, regulates apoptosis of human monocytic THP-1 cells induced under growth factor deprivation. To investigate this point, we used fimbriae of Porphyromonas gingivalis, a pathogen causing periodontal disease, which is a chronic inflammatory disease. The fimbriae inhibited apoptosis of the cells under growth factor deprivation. This inhibitory action of the fimbriae was completely neutralized by anti-fimbrial antibody. The fimbriae stimulated activation of extracellular signal-regulated kinase (ERK) and expression of cyclin-dependent kinase inhibitor p21 Cip/WAF1 (p21) in the cells. The stimulatory effect of the fimbriae on the expression of the p21 protein was inhibited by treatment with PD98059, a specific inhibitor of ERK. The cell apoptosis was inhibited by treatment with Ac-DEVD-CHO, an inhibitor of caspase-3. The fimbriae inhibited the serum withdrawal-induced cleavage of the caspase-3 proform and poly(ADP-ribose) polymerase, one of the caspase-3 substrates. Furthermore, PD98059 and antisense p21 oligonucleotide blocked the fimbrial inhibition of apoptosis and caspase-3 activation of the cells induced by serum withdrawal. These results show that the bacterial fimbriae inhibited apoptosis of THP-1 cells induced under growth factor deprivation via ERK-dependent expression of p21. The present study suggests that bacterial fimbriae act as potent regulators of chronic inflammatory disease, e.g., periodontal disease, through blocking apoptosis of monocytes/macrophages.

Documentos Relacionados

• Phosphorylated Extracellular Signal-regulated Protein Kinases 1 and 2 Phosphorylate Sp1 on Serine 59 and Regulate Cellular Senescence via Transcription of p21Sdi1/Cip1/Waf1*
• Glutamate Induces Phosphorylation of Elk-1 and CREB, Along with c-fos Activation, via an Extracellular Signal-Regulated Kinase-Dependent Pathway in Brain Slices
• N-Terminal Ubiquitination of Extracellular Signal-Regulated Kinase 3 and p21 Directs Their Degradation by the Proteasome
• Cytosolic Retention of Phosphorylated Extracellular Signal-Regulated Kinase and a Rho-Associated Kinase-Mediated Signal Impair Expression of p21Cip1/Waf1 in Phorbol 12-Myristate-13- Acetate-Induced Apoptotic Cells
• Extracellular signal-regulated kinases: ERKs in progress.