Tesis doctoral de Basavaraj Udapudi
Historically, e2f1 has been associated exclusively with its function as a transcription factor that is essential for the gl/s transition. Recent study on e2f1 has become a new focus since it has been implicated in other cellular processes such as cell cycle arrest and apoptosis. The activation of the pi 3-kinase pathway is determinant in the cell decisions in which e2f1 participates. Previous studies of our group have demonstrated that activation of the phosphatidylinositol 3-kinase/protein kinase b (pi 3-kinase/pkb) pathway changes e2f-regulated transcriptional activity indirectly through its targets. Gsk3íY is a direct downstream effector of pkb and also plays an essential role in the regulation of neuronal apoptosis. We wanted to investigate whether these proteins could share a common apoptotic signal pathway in neuronal cells. With this intention, we developed a pc12 er-e2f1 stable cell line in which e2f1 activity was dependent on the presence of 4-hydroxitamoxifen. E2f1 activation produced apoptosis in naive and post-mitotic cells; serum and nerve growth factor respectively protected them from e2f1 apoptotic stimuli. The presence of specific gsk3íY inhibitors sb216763 and licl completely protected cells from apoptosis induced by e2f1 activation. In addition, knocked down gsk3íY experiments by small interference rnas have demonstrated that a reduction of gsk3íY protein levels can lower the apoptotic effect of e2f1. Finally, we demonstrated that the apoptotic effect of e2f1 is not due to the regulation of gsk3íY activity, and that the inhibitory effect of gsk3íY inhibitor sb216763 on e2f1 induced apoptosis could be due to an alteration in the e2f1-regulated transcription gene pattern. Further, we used flavopiridol to block e2f1 activity to determine whether e2f1 plays a role in the modulation of gsk3íY induced apoptosis. Flavopiridol, inhibitor of cdk, reduced the basic levels of apoptosis in gsk3-dp and gsk3-kd transfected cells, although it was not statistically significant. We wanted to investigate whether nf-kb contributes in the apoptosis induced by e2f1. The results obtained demonstrate overexpression of e2f1 able to activate nf-kb activity in pc12 cells on serum starved conditions. In conclusion, our results not only help us to understand the role of gsk3íY and e2f1 in neuronal apoptosis but may also facilitate in the neurodegenerative therapeutic strategies.
Datos académicos de la tesis doctoral «Apoptotic action of e2 f.1 requires glucogen synthase kinase 3-ss activity in pc12 cells«
- Título de la tesis: Apoptotic action of e2 f.1 requires glucogen synthase kinase 3-ss activity in pc12 cells
- Autor: Basavaraj Udapudi
- Universidad: Barcelona
- Fecha de lectura de la tesis: 30/06/2008
Dirección y tribunal
- Director de la tesis
- Albert Tauler Girona
- Tribunal
- Presidente del tribunal: neus Agell jane
- gisela García álvarez (vocal)
- priam Villalonga smith (vocal)
- Santiago Ambrosio viale (vocal)