Linking Heat Shock Protein 70 and Parkin in Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disease that affects millions of elderly people worldwide and is characterized by the progressive loss of dopaminergic neurons in the substantia nigra pars compacta (SNpc). The precise mechanisms underlying the pathogenesis of PD are still not fully understood, but it is well accepted that the misfolding, aggregation, and abnormal degradation of proteins are the key causative factors of PD. Heat shock protein 70 (Hsp70) is a molecular chaperone that participates in the degradation of misfolded and aggregated proteins in living cells and organisms. Parkin, an E3 ubiquitin ligase, participates in the degradation of proteins via the proteasome pathway. Recent studies have indicated that both Hsp70 and Parkin play pivotal roles in PD pathogenesis. In this review, we focus on discussing how dysregulation of Hsp70 and Parkin leads to PD pathogenesis, the interaction between Hsp70 and Parkin in the context of PD and their therapeutic applications in PD.

Design and Synthesis of a Mitochondrial-Targeted JNK Inhibitor and Its Protective Effect on Parkinson's Disease Phenotypes.

C-Jun N-terminal kinase (JNK) is a key mediator involved in a variety of physiological processes. JNK activation is regulated in a complex manner by upstream kinases and phosphatases, and plays an important role in physiological processes such as the immune response and neuronal function. Therefore, JNK has become a therapeutic target for neurodegenerative diseases, ankylosing spondylitis, psoriasis, arthritis and other diseases. Inhibition of JNK activation in mitochondria holds great potential for Parkinson's disease (PD) therapy. However, no specific mitochondrial-targeted JNK inhibitor has been reported. We have developed a mitochondrial-targeted JNK inhibitor, P2, by linking a mitochondrial-specific cell-penetrating peptide to SP600125 (SP), a commercialized specific inhibitor of JNK. We found that P2 specifically inhibited mitochondrial JNK phosphorylation instead of nuclear JNK signaling. Further studies showed that P2 effectively rescued PD phenotypes both in vitro and in vivo, thus indicating that it is a potential therapeutic for PD.