Effect of Red <i>Panax ginseng</i>on Mitochondrial Dynamics and Bioenergetics in HaCaT Cells Exposed to Urban Pollutants

Background: Urban air pollution contributes to lung and cardiovascular system dysfunction, making it a major concern for human health. Its impact on skin integrity, associated with increased occurrence of atopic dermatitis, is now recognized, but its cellular mechanisms remain poorly understood. Objective: In the present study we aimed at establishing the impact of urban pollutant on mitochondrial dynamics and bioenergetics using the HaCaT cell model. We also sought to establish the protective effect of ECH-5195 (red Panax ginseng extract), standardized in ginsenosides, in reversing pollution-induced mitochondrial defects. Methods: Urban pollution exposure was mimicked by 1 h exposure of HaCaT cells with standardized atmospheric particulate matter containing PAHs, nitro-PAHs, PCB congeners, and chlorinated pesticides with a mean particulate diameter of 5.85 μm (SRM1648). Results: The presence of urban pollutant in the cultures increased the prevalence of hyperfission by 1.41-fold (p = 0.023) and fission by 1.35 fold (p = 0.006) in the reticular mitochondrial network. ECH-5195 reduced both pollution-induced hyperfission by 0.54-fold (p = 0.004) and fission by 0.68-fold (p = 0.0006) normalizing the mitochondrial reticular network. Pollution exposure was associated with a significant reduction of basal OCR and increased lactate production, pushing the cell to rely on glycolysis for ATP production. When ECH-5195 was used, OCR was significantly increased, and the glycolytic contribution to ATP production was reduced while both oxidative phosphorylation and mitochondrial respiration were increased demonstrating mitochondrial re-engagement in ATP production. Conclusions: Pollution exposure was disruptive for both the mitochondrial network dynamics and mitochondrial respiration. Ginsenosides in ECH-5195 efficiently protected both from pollution-induced defects.

Mitochondria-associated endoplasmic reticulum membranes allow adaptation of mitochondrial metabolism to glucose availability in the liver

Mitochondria-associated endoplasmic reticulum membranes(MAM)play a key role in mitochondrial dynamics and function and in hepatic insulin action.Whereas mitochondria are important regulators of energy metabolism,the nutritional regulation of MAM in the liver and its role in the adaptation of mitochondria physiology to nutrient availability are unknown.In this study,we found that the fasted to postprandial transition reduced the number of endoplasmic reticulum-mitochondria contact points in mouse liver.Screening of potential hormonal/metabolic signals revealed glucose as the main nutritional regulator of hepatic MAM integrity both in vitro and in vivo.Glucose reduced organelle interactions through the pentose phosphate-protein phosphatase 2A(PP-PP2A)pathway,induced mitochondria fission,and impaired respiration.Blocking MAM reduction counteracted glucose-induced mitochondrial alterations.Furthermore,disruption of MAM integrity mimicked effects of glucose on mitochondria dynamics and function.This glucose-sensing system is deficient in the liver of insulin-resistant ob/ob and cyclophilin D-KO mice,both characterized by chronic disruption of MAM integrity,mitochondrial fission,and altered mitochondrial respiration.These data indicate that MAM contribute to the hepatic glucose-sensing system,allowing regulation of mitochondria dynamics and function during nutritional transition.Chronic disruption of MAM may participate in hepatic mitochondrial dysfunction associated with insulin resistance.

Genomic heterogeneity meets cellular energetics: crosstalk between the mitochondria and the cell cycle

Changes in cellular energetics and genomic instability are two characteristics of cancers that have been studied independently.Evidence of cross-talk between mitochondria function and nuclear function has started to emerge,suggesting that these pathways can influence one another.Here we review recent evidence that links the mitochondria and the cell cycle.This evidence indicates bidirectional cross-talk where mitochondria function can regulate the cell cycle and induce genomic instability,and conversely,the cell cycle machinery regulates mitochondria function.Implications for this cross-talk in the development of cancer are discussed.