Induced Apoptosis In THP-1 Cells Research Articles

Inhibition of TLR8 mediated signaling promotes BCG induced apoptosis in THP-1 cells

Apoptosis was considered as one of the important host defense mechanisms against mycobacteria infection. In macrophage, the main target cell of Mycobacterium tuberculosis, apoptosis after infection could help kill the bacillus inside and process the antigens for further presentation and proper immune response. Here, we identified a role of TLR8 during the apoptosis induced by Bacillus Calmette Guérin (BCG) infection in THP-1 cells. Knockdown TLR8 further increased the apoptosis induced by BCG infection, and this enhanced apoptosis was caspase-dependent. During this process, Erk1/2, JNK and NFκB pathways were negatively affected and contributed to the enhanced apoptosis.

Apoptosis inducing effects of oridonin on THP-1 cells and its mechanisms of action

Objective To investigate the apoptosis inducing effects of oridonin on leukemic THP-1 cells and its mechanisms of action. Methods THP-1 cells in culture medium in vitro were given different concentrations of oridonin (16～56 μmol/L) for 24, 48 and 72 h. The inhibitory rate of the cells were measured by MTT assay, apoptotic morphology was observed by Hoechst 33258 staining, and Annexin V/PI staining was used to detect cell apoptosis by flow cytometry (FCM). Caspase-3 and poly (ADP-ribose) polymerase (PARP) expression were detected by Western blotting. Results Oridonin (over 32 μmol/L) could inhibit the growth of THP-1 cells and cause apoptosis remarkably, the suppression was both in time-and dose-dependentmanner. Marked morphological changes of cell apoptosis such as condensation of chromatin was clearly observed by Hoechst 33258 staining, and Annexin V/PI staining showed that apoptotic cells gradually increased after the cells treated with oridinon. Western blotting showed cleavage of the caspase-3 zymogen protein (32×103), with the appearance of its 20×103 subunit, and a cleaved 89×103 fragment of 116×103 PARP was also found. Conclusion Oridonin can inhibit cell growth and induce apoptosis in THP-1 cells via activation of caspase-3. The results indicated that oridonin might be an important potential anti-leukemia reagent. Key words: Oridonin; THP-1 cell; Apoptosis