Mitochondrial unfolded protein response: An emerging pathway in human diseases

Mitochondrial unfolded protein response (UPRmt) is a mitochondria stress response, which the transcriptional activation programs of mitochondrial chaperone proteins and proteases are initiated to maintain proteostasis in mitochondria. Additionally, the activation of UPRmt delays aging and extends lifespan by maintaining mitochondrial proteostasis. Growing evidences suggests that UPRmt plays an important role in diverse human diseases, especially ageing-related diseases. Therefore, this review focuses on the role of UPRmt in ageing and ageing-related neurodegenerative diseases such as Alzheimer's disease, Huntington's disease and Parkinson's disease. The activation of UPRmt and the high expression of UPRmt components contribute to longevity extension. The activation of UPRmt may ameliorate Alzheimer's disease, Parkinson's disease and Huntington's disease. Besides, UPRmt is also involved in the occurrence and development of cancers and heart diseases. UPRmt contributes to the growth, invasive and metastasis of cancers. UPRmt has paradoxical roles in heart diseases. UPRmt not only protects against heart damage, but may sometimes aggravates the development of heart diseases. Considering the pleiotropic actions of UPRmt system, targeting UPRmt pathway may be a potent therapeutic avenue for neurodegenerative diseases, cancers and heart diseases.