[Effect of Silencing UVRAG on Mitophagy in Leukemia Cells K562].

OBJECTIVE: To explore the effect of UVRAG on mitophagy in leukemia cells K562. METHODS: K562 cells were induced with different concentrations of mitophagy inducer carbonylcyanide-m-chlorophenylhydrazone (CCCP) for 6, 12 and 24 hours, and the cell viability was detected by the CCK-8 assay. K562 cells were divided into NC, UVRAG-siRNA, UVRAG-siRNA+CCCP, and CCCP group, while Western blot was used to detect the expression of UVRAG protein. Flow cytometry was used to detect the changes in reactive oxygen species (ROS) and mitochondrial structural integrity. The expressions of autophagy related proteins P62 and LC3-Ⅱ/LC3-Ⅰ were detected by Western blot. RESULTS: Compared with NC group, the expression of UVRAG protein in UVRAG -siRNA group significantly decreased (P<0.01). Compared with CCCP group, in UVRAG -siRNA+CCCP group ROS, mitochondrial structure damage, and the expression of LC3-Ⅱ/LC3-Ⅰ decreased significantly (P<0.05, P<0.05, P<0.01), while the expression of P62 protein increased (P<0.05). Compared with NC group, the differences in the expressions of P62 and LC3-Ⅱ/LC3-Ⅰ protein, ROS, and mitochondrial structural integrity in UVRAG -siRNA group were not obvious (P>0.05). CONCLUSION: Under the treatment of CCCP, silencing UVRAG can inhibit mitophagy in K562 cells.

Perspectives of drug-based neuroprotection targeting mitochondria.

Mitochondrial dysfunction has been reported in most neurodegenerative diseases. These anomalies include bioenergetic defect, respiratory chain-induced oxidative stress, defects of mitochondrial dynamics, increase sensitivity to apoptosis, and accumulation of damaged mitochondria with instable mitochondrial DNA. Significant progress has been made in our understanding of the pathophysiology of inherited mitochondrial disorders but most have no effective therapies. The development of new metabolic treatments will be useful not only for rare mitochondrial disorders but also for the wide spectrum of common age-related neurodegenerative diseases shown to be associated with mitochondrial dysfunction. A better understanding of the mitochondrial regulating pathways raised several promising perspectives of neuroprotection. This review focuses on the pharmacological approaches to modulate mitochondrial biogenesis, the removal of damaged mitochondria through mitophagy, scavenging free radicals and also dietary measures such as ketogenic diet.

Derivatives of the cationic plant alkaloids berberine and palmatine amplify protonophorous activity of fatty acids in model membranes and mitochondria.

Previously it has been shown by our group that berberine and palmatine, penetrating cations of plant origin, when conjugated with plastoquinone (SkQBerb and SkQPalm), can accumulate in isolated mitochondria or in mitochondria of living cells and effectively protect them from oxidative damage. In the present work, we demonstrate that SkQBerb, SkQPalm, and their analogs lacking the plastoquinone moiety (C10Berb and C10Palm) operate as mitochondria-targeted compounds facilitating protonophorous effect of free fatty acids. These compounds induce proton transport mediated by small concentrations of added fatty acids both in planar and liposomal model lipid membranes. In mitochondria, such an effect can be carried out by endogenous fatty acids and the adenine nucleotide translocase.