Trichomonas vaginalis-induced apoptosis in RAW264.7 cells is regulated through Bcl-xL, but not Bcl-2.
The purpose of this study was to determine whether anti-apoptotic proteins of the Bcl-2 family such as Bcl-2 and Bcl-x(L), proteins that confer resistance to apoptotic death from some stimuli, block apoptotic cell death in RAW264.7 cells upon treatment with Trichomonas vaginalis. In this study, the expression level of Bcl-2 was unchanged throughout the course of apoptotic cell death, and overexpressed Bcl-2 did not prevent release of cytochrome c, the significant change of the membrane potential, activation of caspases, and PARP cleavage in T. vaginalis-treated RAW264.7 cells. On the other hand, Bcl-x(L)expression was decreased after T. vaginalis treatment accompanied with Bax activation. Furthermore, we showed that release of mitochondrial cytochrome c, cleavage of caspase-9 and PARP during apoptosis in T. vaginalis-treated RAW264.7 cells were considerably diminished by transfection with overexpressed Bcl-x(L), and overexpressed Bcl-x(L)could inhibit T. vaginalis-induced apoptosis in RAW264.7 cells. In addition, interestingly, pre-treatment with caspase inhibitors, Boc-D-FMK and Z-DEVD-FMK, significantly abolished T. vaginalis-induced down-regulation of Bcl-x(L), suggesting that caspase-3 may play a pivotal role in the process of apoptosis as well as the down-regulation of Bcl-x(L)by T. vaginalis. Therefore, these results suggest that T. vaginalis-induced apoptosis in RAW264.7 cells can occur via a Bcl-x(L)-dependent apoptotic mechanism.
Department of Biomedical Laboratory Science, College of Health Science, Yonsei University, Wonju, South Korea.
J-H
JH
Chang
Y-S
YS
Ryang
S-K
SK
Kim
J-Y
JY
Park
D000818:Animals; D017209:Apoptosis / Q000276:immunology / Q000502:physiology*; D002460:Cell Line; D015870:Gene Expression; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology / Q000469:parasitology / Q000473:pathology; D051379:Mice; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000276:immunology / Q000502:physiology*; D014162:Transfection; D014245:Trichomonas Infections / Q000276:immunology / Q000469:parasitology / Q000473:pathology; D014246:Trichomonas vaginalis / Q000276:immunology* / Q000472:pathogenicity*; D051020:bcl-X Protein
C494812:Bcl2l1 protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein