Parkin siRNA Research Articles

Carnosic Acid Attenuates 6-Hydroxydopamine-Induced Neurotoxicity in SH-SY5Y Cells by Inducing Autophagy Through an Enhanced Interaction of Parkin and Beclin1.

Enhanced removal of abnormal protein aggregates or injured organelles through autophagy is related to neuroprotection in Parkinson's disease. In this study, we explored whether the induction of autophagy is associated with the neuroprotection of rosemary carnosic acid (CA) against 6-hydroxydopamine (6-OHDA)-induced neurotoxicity in SH-SY5Y cells. The results indicated that cells treated with CA had increased protein levels of parkin and autophagy-related markers, including phosphatidylinositol 3-kinase p100, Beclin1, autophagy-related gene 7, and microtubule-associated protein 1 light chain 3-II, as well as enhanced formation of autophagic vacuoles. Treatment of cells with 6-OHDA decreased the levels of parkin and the autophagy markers, but CA pretreatment reversed these effects. However, wortmannin (an autophagosome formation blocker) pretreatment attenuated the effect of CA. After CA pretreatment, the induction of cleaved caspase 3, cleaved poly-ADP ribose polymerase, and nuclear condensation by 6-OHDA were alleviated. Both wortmannin and bafilomycin A1 (an autophagosome-lysosome fusion blocker) inhibited the anti-apoptosis effects of CA. Additionally, we performed immunoprecipitation with anti-parkin antibody and found that the interaction of parkin and Beclin1 protein was reduced by 6-OHDA but that this effect was reversed in cells pretreated with CA. Moreover, transfection of parkin siRNA in cells inhibited the ability of CA to alleviate 6-OHDA-decreased autophagy-related markers and nuclear condensation. In conclusion, CA protects against 6-OHDA-induced apoptosis by inducing autophagy through the interaction of parkin and Beclin1. These results provide a future strategy for use of CA in the prevention of Parkinson's disease.

Carnosic acid prevents 6-hydroxydopamine induced-apoptosis associated with modulation ARTS and XIAP by parkin in SH-SY5Y cells

U the neuroprotective effects of carnosic acid (CA) from rosemary has attracted increasing attention in recent years. Parkin promotes the degradation of mitochondria pro-apoptotic ARTS (apoptosis-related protein in the TGF-β signaling pathway) protein and prevents it antagonizes XIAP (X-linked inhibitors of apoptosis proteins) leading to caspase activation. In this present study, we explored whether CA could prevent 6-hydroxydopamine (6-OHDA)-induced apoptosis via modulation of ARTS and XIAP by parkin in SH-SY5Y cells. The results showed that pretreatment cells with CA reduced 6-OHDA-induced the nuclear condensation and apoptotic proteins. Treatment cells with 6-OHDA increased ARTS protein and decreased XIAP protein as well as parkin protien. However, CA pretreatment reversed the effect by 6-OHDA. Performing immunoprecipitation using an antiARTS antibody, 6-OHDA increased the XIAP protein. In contrast, CA pretreatment reduced XIAP protein and increased ubiquitin protein in 6-OHDA treated cells. Silencing of XIAP reduced the CA inhibited 6-OHDA-increased the cleavage of caspase 9, 3, 7 and PARP. With parkin siRNA, CA reversed the 6-OHDA-induced ARTS and reduced XIAP was inhibited, which resulted in increasing apoptotic related proteins. In conclusion, CA protects SH-SY5Y cells against 6-OHDA-stimulated apoptosis via induction of parkin by enhancing the ubiquitination of ARTS, leading to induction of XIAP.

Ketoconazole induces apoptosis in rat cardiomyocytes through reactive oxygen species-mediated parkin overexpression.

Azole antifungals such as ketoconazole are generally known to induce a variety of heart function side effects, e.g., long-QT syndrome and ventricular arrhythmias. However, a clear mechanism for the action of ketoconazole in heart cells has not been reported. In the present study, we assessed the correlation between ketoconazole-induced apoptosis and the alteration of genes in response to ketoconazole in rat cardiomyocytes. Cardiomyocyte viability was significantly inhibited by treatment with ketoconazole. Ketoconazole also stimulated H2O2 generation and TUNEL-positive apoptosis in a dose-dependent manner. DNA microarray technology revealed that 10,571 genes were differentially expressed by more than threefold in ketoconazole-exposed cardiomyocytes compared with untreated controls. Among these genes, parkin, which encodes a component of the multiprotein E3 ubiquitin ligase complex, was predominantly overexpressed among those classified as apoptosis- and reactive oxygen species (ROS)-related genes. The expression of parkin was also elevated in cardiomyocytes treated with exogenous H2O2. Moreover, cell viability and apoptosis in response to ketoconazole were inhibited in cardiomyocytes treated with ROS inhibitors and transfected with parkin siRNA. From the present findings, we concluded that ketoconazole may increase the expression of parkin via the ROS-mediated pathway, which consequently results in the apoptosis and decreased viability of cardiomyocytes.