PINK1/Parkin mediated mitophagy ameliorates palmitic acid-induced apoptosis through reducing mitochondrial ROS production in podocytes.

Diabetic nephropathy (DN), the primary cause of end-stage renal disease (ESRD), is often accompanied by dyslipidemia, which is closely related to the occurrence and development of DN and even the progression to ESRD. Mitophagy, the selective degradation of damaged and dysfunctional mitochondria by autophagy, is a crucial mitochondrial quality control mechanism, and largely regulated by PINK1 (PTEN-induced putative kinase 1)/Parkin signaling pathway. In the present study, we demonstrated that PA induced mitochondrial damage and excessive mitoROS generation in podocytes. We also found PA treatment resulted in the activation of mitophagy by increasing co-localization of GFP-LC3 with mitochondria and enhancing the formation of mitophagosome, stabilization of PINK1 and mitochondrial translocation of Parkin, which indicated that PINK1/Parkin pathway was involved in PA-induced mitophagy in podocytes. Furthermore, inhibition of mitophagy by silencing Parkin dramatically aggravated PA-induced mitochondrial dysfunction, mitoROS production, and further enhanced PA-induced apoptosis of podocytes. Finally, we showed that PINK1/Parkin pathway were up-regulated in kidney of high fat diet (HFD)-induced obese rats. Taken together, our results suggest that PINK1/Parkin mediated mitophagy plays a protective role in PA-induced podocytes apoptosis through reducing mitochondrial ROS production and that enhancing mitophagy provides a potential therapeutic strategy for kidney diseases with hyperlipidemia, such as DN.

Jiang XS ，Chen XM ，Hua W ，He JL ，Liu T ，Li XJ ，Wan JM ，Gan H ，Du XG ... -  《-》

Hydrogen exerts neuroprotective effects on OGD/R damaged neurons in rat hippocampal by protecting mitochondrial function via regulating mitophagy mediated by PINK1/Parkin signaling pathway.

Cerebral ischemia/reperfusion injury (IRI) is a serious complication during the treatment of stroke patients with very few effective clinical treatment. Hydrogen (H2) can protect mitochondria function and have favorable therapeutic effects on cerebral IRI. Mitophagy plays an important role in eliminating damaged or dysfunctional mitochondria and maintaining mitochondria homeostasis. However, whether the protection of H2 on cerebral IRI is via regulating mitophagy is still unknown. In this study, OGD/R damaged hippocampal neurons were used to mimic cerebral IRI in vivo and we detected the effect of H2, Rap (autophagy activator) and 3-MA (autophagy inhibitor) on OGD/R neurons. The results of MTT indicated that H2 and RAP could increase cell viability after OGD/R treatment, while 3-MA further aggravated injury and inhibited the protection of H2 and RAP. Furthermore, the intracellular ROS and apoptosis ratio were determined, the results showed that ROS and apoptosis level significantly increased after OGD/R, H2 and RAP effectively restrained the increment of ROS level and apoptosis ratio but their protective effect can be weakened by 3-MA. Mitochondrial membrane potential (MMP) and mitophagy level were also determined, the data showed that H2 and RAP protected against the loss of MPP and increased the co-localization of mitochondria with GFP-LC3 while 3-MA exerted antagonistic effect. At last, the mitophagy-related factors LC3, PINK1 and Parkin expression were detected and analyzed. We found that the expression of LC3 was increased after OGD/R which can be further enhanced by H2 and RAP treatment, but treatment with 3-MA was opposite. The result revealed H2 and RAP could activate mitophagy while 3-MA inhibit mitophagy. In addition, the study found H2 and RAP could significantly induce the expression of PINK1 and Parkin in OGD/R neurons which was inhibited by 3-MA. Taken together, our findings demonstrated H2 had a neuroprotective effect on OGD/R damaged neurons by protecting mitochondrial function and the potential protection mechanism may closely related to enhancement of mitophagy mediated by PINK1/Parkin signaling pathway.

Wu X ，Li X ，Liu Y ，Yuan N ，Li C ，Kang Z ，Zhang X ，Xia Y ，Hao Y ，Tan Y ... -  《-》

PINK1-Parkin-Mediated Mitophagy Protects Mitochondrial Integrity and Prevents Metabolic Stress-Induced Endothelial Injury.

Wu W ，Xu H ，Wang Z ，Mao Y ，Yuan L ，Luo W ，Cui Z ，Cui T ，Wang XL ，Shen YH ... -  《PLoS One》

PINK1/Parkin-mediated mitophagy was activated against 1,4-Benzoquinone-induced apoptosis in HL-60 cells.

Hematotoxicity of benzene is derived mainly from its active metabolite, 1,4-Benzoquinone (1,4-BQ), which induces cell apoptosis and mitochondrial damage. Damaged mitochondria are degraded through a specialized autophagy pathway, called mitophagy, which is driven by PINK1/Parkin signaling. However, whether mitophagy is involved in 1,4-BQ-induced toxicity remains unclear. This study was designed to investigate whether PINK1/Parkin-mediated mitophagy is activated in 1,4-BQ-treated HL-60 cells, and the roles mitophagy plays in 1,4-BQ-induced apoptosis. Our results demonstrated that 1,4-BQ induced autophagy in HL-60 cells, characterized by increased LC3-II/LC3-I ratio and Beclin1 expression, as well as decreased expression of p62. We confirmed the presence of mitophagosomes using electron microscopy, and found that 1,4-BQ-induced autophagy was blocked by pretreatment with the mitophagy inhibitor Cyclosporine A (CsA). In addition, we found that 1,4-BQ induced mitochondrial stress through decreased mitochondrial membrane potential (MMP) and increasedproduction of reactive oxygen species (ROS). We also confirmed that 1,4-BQ-induced mitophagy was mediated by the PINK1/Parkin pathway, illustrated by increased expression of PINK1 and Parkin mRNA and protein. Finally, we examined 1,4-BQ-induced apoptosis with or without CsA, which demonstrated that apoptosis increased after mitophagy inhibition, suggesting that mitophagy has a protective effect in this context. In conclusion, this study demonstrates that the activated PINK1/Parkin-mediated mitophagy exerts a significantly protective effect against 1,4-BQ-induced apoptosis in HL-60 cells.

Zhang C ，Yu X ，Gao J ，Zhang Q ，Sun S ，Zhu H ，Yang X ，Yan H ... -  《-》

Scutellarin ameliorates high glucose-induced vascular endothelial cells injury by activating PINK1/Parkin-mediated mitophagy.

Scutellarin (Scu) is one of the main active ingredients of Erigeron breviscapus (Vant.) Hand.-Mazz which has been used to treat cardiovascular disease including vascular dysfunction caused by diabetes. Scu also has a protective effect on vascular endothelial cells against hyperglycemia. However, molecular mechanisms underlying this effect are not clear. This aim of this study was to investigate the effect of Scu on human umbilical vein endothelial cells (HUVECs) injury induced by high glucose (HG), especially the regulation of PTEN-induced kinase 1 (PINK1)/Parkin-mediated mitophagy. HUVECs were exposed to HG to induce vascular endothelial cells injury in vitro. Cell viability was assessed by MTT assay. The extent of cell apoptosis was measured by Hoechst staining and flow cytometry. Mitophagy was assayed by fluorescent immunostaining, transmission electron microscope and immunoblot. Besides, virtual docking was conducted to validate the interaction of PINK1 protein and Scu. We found that Scu significantly increased cell viability in HG-treated HUVECs. Scu reduces the expression of Bcl-2, Bax and cytochrome C (Cyt.c) to inhibit apoptosis through a mitochondria-dependent pathway. Meanwhile, Scu improved the overload of reactive oxygen species (ROS), superoxide dismutase (SOD) activity and SOD2 protein expression, and reversed the collapse of mitochondrial membrane potential. Besides, Scu increased autophagic flux, improved the expression of microtubule-associated protein 1 light chain 3 Ⅱ (LC3 II), Beclin 1 and autophagy-related gene 5 (Atg 5) and decreased the expression of Sequestosome1/P62 in HG-treated HUVECs. Furthermore, Scu improved the expressions of PINK1, Parkin, and Mitofusin2, which revealed the enhancement of mitophagy. Moreover, the beneficial effects of Scu on HG-induced low expression of Parkin, overproduction of ROS, and over expressions of P62, Cyt.c and Cleaved caspase-3 were weakened by PINK1 gene knockdown. Molecular docking suggested good interaction of Scu and PINK1 protein. These results suggest that Scu may protect vascular endothelial cells against hyperglycemia-induced injury by up-regulating mitophagy via PINK1/Parkin signal pathway.

Xi J ，Rong Y ，Zhao Z ，Huang Y ，Wang P ，Luan H ，Xing Y ，Li S ，Liao J ，Dai Y ，Liang J ，Wu F ... -  《-》