Study On Molecular Mechanism Of Cell Apoptosis By Fluorescence Resonance Energy Transfer

Cell apoptosis is an important biological process that plays an essential role incell growth and its response to outside stimulations. Some study on cell apoptosis hasbeen carried out, but the study is still too limited in the domain of molecularmechanisms of cell apoptosis. In our work, we focus our study on the molecularmechanism of cell apoptosis using FRET technique and fluorescence probes.Firstly, we observed the location of BimL and Bax in normal condition, and thetranslocation of BimL and Bax after UV irradiation at a single living level, using laserscanning confocal microscope and fluorescence proteins. The results showed that, innormal condition, Bax distributed evenly in both cytoplasm and nucleus and BimLhad a cytoplamic distribution. However, during UV irradiation-induced apoptosis,BimL and Bax translocated to mitochondria respectively. Therefore, usingfluorescence proteins and laser confocal scanning microscope to observe the changeof proteins subcellular location, the subcellular location of Bax and BimL in livingcells were shown truly, which provide the basis for studying on the function of BimLand Bax.Secondly, in order to study the mechanism by which BimL activates Bax toinduce cell apoptosis, we observe the dynamic interaction between BimL and Baxduring UV irradiation-induced apoptosis in living cells using laser confocal scanningmicroscope and fluorescence resonance energy transfer technique. The results showedthat BimL translocated to mitochondria during UV irradiation-induced apoptosis.Moreover, inhibition of BimL activation delayed Bax translocation and subsequentapoptosis. However, BimL did not activate Bax directly. Our results demonstrate thatBim is involved in UV irradiation-induced apoptosis by indirectly activating Bax.Finally, to investigate the mechanisms through which the inhibitions ofsalidroside on the apoptosis induced by Aβ_25-35 in PC12 cells, Alzheimer's disease cellmodel was constructed using PC12 cell treated with 30μM Aβ_25-35 to induce apoptosis. The inhibition of salidroside on the apoptosis induced by Aβ_25-35 in PC12 cells wereobserved using fluorescence resonance energy transfer technique. The results showedthat salidroside elevated the cell survival by inhibiting the Aβ_25-35-induced apoptosisin a dose-dependent manner, and that salidroside greatly inhibited the caspase-3activation. Furthermore, the apoptosis induced by Aβ_25-35 was independent of thecaspase-8 activation. In conclusion, these data indicate that salidroside can protect thePC12 cells from Aβ_25-35-induced apoptosis by inhibiting the activation of caspase-3.