Research Paper|Volume 12, Issue 24|pp 25035—25059

δ-opioid receptor activation protects against Parkinson’s disease-related mitochondrial dysfunction by enhancing PINK1/Parkin-dependent mitophagy

Yuan Xu^1,^2,⁴, Feng Zhi^1,², Jiahao Mao^1,², Ya Peng¹, Naiyuan Shao¹, Gianfranco Balboni³, Yilin Yang^1,², Ying Xia⁴

¹Department of Neurosurgery, The First People’s Hospital of Changzhou, Changzhou, Jiangsu, China
²Modern Medical Research Center, The Third Affiliated Hospital of Soochow University, Changzhou, Jiangsu, China
³Department of Life and Environment Sciences, University of Cagliari, Cagliari, Italy
⁴Shanghai Key Laboratory of Acupuncture Mechanism and Acupoint Function, Department of Aeronautics and Astronautics, Fudan University, Shanghai, China

* Equal contribution

Received: February 5, 2020Accepted: July 31, 2020Published: November 10, 2020

Copyright: © 2020 Xu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Our previous studies have shown that the δ-opioid receptor (DOR) is an important neuroprotector via the regulation of PTEN-induced kinase 1 (PINK1), a mitochondria-related molecule, under hypoxic and MPP⁺ insults. Since mitochondrial dysfunctions are observed in both hypoxia and MPP⁺ insults, this study further investigated whether DOR is cytoprotective against these insults by targeting mitochondria. Through comparing DOR-induced responses to hypoxia versus MPP⁺-induced parkinsonian insult in PC12 cells, we found that both hypoxia and MPP⁺ caused a collapse of mitochondrial membrane potential and severe mitochondrial dysfunction. In sharp contrast to its inappreciable effect on mitochondria in hypoxic conditions, DOR activation with UFP-512, a specific agonist, significantly attenuated the MPP⁺-induced mitochondrial injury. Mechanistically, DOR activation effectively upregulated PINK1 expression and promoted Parkin’s mitochondrial translocation and modification, thus enhancing the PINK1-Parkin mediated mitophagy. Either PINK1 knockdown or DOR knockdown largely interfered with the DOR-mediated mitoprotection in MPP⁺ conditions. Moreover, there was a major difference between hypoxia versus MPP⁺ in terms of the regulation of mitophagy with hypoxia-induced mitophagy being independent from DOR-PINK1 signaling. Taken together, our novel data suggest that DOR activation is neuroprotective against parkinsonian injury by specifically promoting mitophagy in a PINK1-dependent pathway and thus attenuating mitochondrial damage.