Parkin-mediated mitophagy protects against TNF-?-induced stress in bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs) have been investigated as cellular therapeutics for intervertebral disc degeneration. However, transplanted BMSCs are prone to be damaged. TNF-alpha is reported to extensively promote degeneration process. Nevertheless, the relationship between BMSCs senescence and TNF-alpha-induced stress has not been elucidated. Previous studies showed that mitophagy is a crucial factor in maintaining cellular homeostasis. Hence, we sought to clarify the role and mechanism of mitophagy in TNF-alpha-induced biological changes of BMSCs. Here, we found that TNF-alpha caused transient senescent damage in the early stage. Meanwhile, Parkin-mediated mitophagy was initiated and weakened the damage through maintaining mitochondria homeostasis. After inhibiting mitophagy by knockdown of Parkin, TNF-alpha irreversibly caused cellular senescence. These results suggested that Parkin-mediated mitophagy played protective role in BMSCs in response to TNF-alpha, which could be a crucial therapeutic target in the future.