TZDs reduce mitochondrial ROS production and enhance mitochondrial biogenesis.
ABSTRACT Although it has been reported that thiazolidinediones (TZDs) may reduce cardiovascular events in type 2 diabetic patients, its precise mechanism is unclear. We previously demonstrated that hyperglycemia-induced production of reactive oxygen species from mitochondria (mtROS) contributed to the development of diabetic complications, and metformin normalized mt ROS production by induction of MnSOD and promotion of mitochondrial biogenesis by activating the PGC-1alpha pathway. In this study, we examined whether TZDs could inhibit hyperglycemia-induced mtROS production by activating the PGC-1alpha pathway. We revealed that pioglitazone and ciglitazone attenuated hyperglycemia-induced ROS production in human umbilical vein endothelial cells (HUVECs). Both TZDs increased the expression of NRF-1, TFAM and MnSOD mRNA. Moreover, pioglitazone increased mtDNA and mitochondrial density. These results suggest that TZDs normalize hyperglycemia-induced mtROS production by induction of MnSOD and promotion of mitochondrial biogenesis by activating PGC-1alpha. This phenomenon could contribute to the prevention of diabetic vascular complications.
- SourceAvailable from: Xiaoqiang Tang[Show abstract] [Hide abstract]
ABSTRACT: Mitochondria are perhaps the most sophisticated and dynamic responsive sensing systems in eukaryotic cells. The role of mitochondria goes beyond their capacity to create molecular fuel and includes the generation of reactive oxygen species, the regulation of calcium, and the activation of cell death. In endothelial cells, mitochondria have a profound impact on cellular function under both healthy and diseased conditions. In this review, we summarize the basic functions of mitochondria in endothelial cells and discuss the roles of mitochondria in endothelial dysfunction and vascular diseases, including atherosclerosis, diabetic vascular dysfunction, pulmonary artery hypertension, and hypertension. Finally, the potential therapeutic strategies to improve mitochondrial function in endothelial cells and vascular diseases are also discussed, with a focus on mitochondrial-targeted antioxidants and calorie restriction.Frontiers in Physiology 05/2014; 5:175. DOI:10.3389/fphys.2014.00175
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ABSTRACT: BACKGROUND AND PURPOSE Peroxisome proliferator-activated receptor (PPAR) agonists exert anti-albuminuric effects. However, the nephroprotective effects of these drugs remain to be fully understood. We have investigated whether gemfibrozil, GW0742 and pioglitazone protect human podocytes against nutrient deprivation (ND)-induced cell death and the role of mitochondrial biogenesis as a cytoprotective process. EXPERIMENTAL APPROACH Immortalized human podocytes were pre-treated with the PPAR agonists and exposed to ND (5 h) under normoxia, hypoxia or in the presence of pyruvate. Cell death was measured at the end of the ND and of the recovery phase (24 h). Mitochondrial mass, cytochrome c oxidase (COX) subunits 1 and 4 were measured as markers of mitochondrial cell content, while membrane potential as an index of mitochondrial function. PGC-1α, NRF1 and Tfam expression was studied, as crucial regulators of mitochondrial biogenesis. KEY RESULTS Cell pre-treatment with gemfibrozil, GW0742, or pioglitazone significantly decreased the ND-induced cell loss, necrosis and apoptosis. These effects were attenuated by hypoxia and potentiated by pyruvate. Pre-treatment with these drugs significantly increased mitochondrial cell content, while it did not affect mitochondrial function. In all these experiments pioglitazone exerted significantly larger effects than gemfibrozil or GW0742. CONCLUSIONS AND IMPLICATIONS Gemfibrozil, GW0742 and pioglitazone may exert direct protective effects on human podocytes. Mitochondrial biogenesis is a cell response to the PPAR agonists related to their cytoprotective activity. These results provide a mechanistic support to the clinical evidence indicating PPAR agonists as disease-modifying agents for glomerular diseases.British Journal of Pharmacology 05/2012; 167(3):641-53. DOI:10.1111/j.1476-5381.2012.02026.x
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ABSTRACT: Huntington's disease (HD) is an autosomal dominant, progressive neurodegenerative disorder, characterized by an array of different psychiatric manifestations, cognitive decline and choreiform movements. The underlying molecular genetic defect is an expanded trinucleotide (CAG)n repeat encoding a polyglutamine stretch in the N-terminus of the huntingtin protein. The mechanisms by which mutant huntingtin causes neuronal dysfunction and degeneration are not fully understood. Nevertheless, impaired ubiquitin-proteasome activity, defective autophagy-lysosomal function, transcriptional dysregulation, oxidative stress, apoptosis, mitochondrial and metabolic dysfunction, and abnormal protein-protein interaction have been shown to play important roles in the pathogenesis of HD. Neurons are energy-demanding and more susceptible to energetic failure and oxidative damage than other types of cell. Given that mitochondria play a central role in both processes of metabolism and oxidative stress, and increasing direct evidence shows mitochondrial abnormalities in both HD mouse models and patients, this article will review the studies of mitochondrial dysfunction, metabolic deficits, and increased oxidative stress in HD, and discuss the potential therapeutics targeting these abnormalities.Chang Gung medical journal 34(2):135-52.