BNIP3/Bcl‑2‑mediated apoptosis induced by cyclic tensile stretch in human cartilage endplate‑derived stem cells
- Chao Yuan
- Luqiao Pu
- Zhiliang He
- Jian Wang
Published online on: October 24, 2017
Copyright: © Yuan et al.
This is an open access article distributed under the terms of Creative Commons Attribution License.
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The present study aimed to investigate the molecular mechanisms of cyclic stretch‑induced apoptosis in human intervertebral disc cartilage endplate‑derived stem cells (CESCs). CESCs were stretched by the Flexercell‑4000™ Tension Plus system, the effect on cell viability was measured by a Cell Counting Kit‑8 assay, while cell apoptosis was detected by flow cytometry. Western blot analysis was used to evaluate the expression of B‑cell lymphoma 2 (Bcl‑2)/adenovirus E1B 19 kDa interacting protein 3 (BNIP3), Bcl‑2, Bcl‑2 homologous antagonist killer (Bak), Bcl‑2‑associated X protein (Bax), Bcl extra large (Bcl‑xl) and the activity of caspase‑3, while Z‑VAD‑FMK was used to inhibit caspase‑3. Compared with the control group, the cell viability decreased in a time‑dependent manner after stretching. Furthermore, cell apoptosis and the activity of caspase‑3 were increased in a time‑dependent manner. The ratio of pro‑death factor BNIP3 to anti‑apoptotic protein Bcl‑2 was significantly increased. When cells were stretched for 36 h, the apoptosis‑associated proteins Bak and Bax were increased, while Bcl‑xl was decreased. The viability and apoptotic ratio of stretched cells were significantly restored after caspase‑3 was repressed. In conclusion, cyclic tensile stretch induced apoptosis of CESCs, which was probably due to upregulation of the expression of BNIP3.