Polyherbal decoction modulates redox homeostasis during Malachite green induced metabolic stress in Saccharomyces cerevisiae

Malachite green (MG) is aquatic pollutant that induces oxidative stress when comes in contact with the living organisms. In Saccharomyces cerevisiae, MG produces intracellular reactive oxygen species (ROS) and these ROS disturb redox homeostasis and cellular functions leading to early cell death. Exogenous supply of natural antioxidants containing polyherbal decoction may play a crucial role in re-establishment of redox homeostasis by ensuring the cell survival. Exposure of MG to Saccharomyces cerevisiae resulted in a significant decrease (97.8%) in colony forming units (CFU). An Ayurvedic polyherbal formulation ‘Vayasthapana Rasayana’ (VR) which contains natural antioxidants from plants viz. Terminalia chebula, Clitoria ternatea, Boerhaavia diffusa, Centella asiatica, Phyllanthus emblica, Asparagus racemossus and Tinospora cordifolia at 1.0 mg/mL concentration could arrest the oxidative stress during MG exposure. Levels of ROS elevated up to 67.3% on MG exposure; while VR supplementation reduced it by 54.7%. MG induced cellular apoptosis in 38% and necrosis in 27% cells, while VR augmentation reduced it to 8%. Activities of antioxidant enzymes like catalase, superoxide dismutase and glutathione peroxidase in MG exposed cells were induced by 408, 144 and 140%, respectively, whereas, VR supplementation lowered the expressions to 102, 57 and 111%, respectively. Induction in caspases 3/7 activity was also found to be reduced by 65.39% after VR augmentation. Similarly, VR modulated activities of oxido-reductases like lignin peroxidase, laccase, NADH-DCIP reductase and MG reductase. VR supplementation also maintained the MG utilization potential of S. cerevisiae up to 20th exposure cycle which was otherwise arrested to 8th cycle. The treatment also decreased the ROS accumulation and nuclear damage, restoring the cell viability up to 94% and retained normal growth dynamics. Thus, VR supplementation could significantly decrease oxidative stress, enhance cell viability and ultimately protect the dying S. cerevisiae cells during MG exposure.

Activated PKB/GSK-3β synergizes with PKC-δ signaling in attenuating myocardial ischemia/reperfusion injury via potentiation of NRF2 activity: Therapeutic efficacy of dihydrotanshinone-I

@#Disrupted redox status primarily contributes to myocardial ischemia/reperfusion injury (MIRI). NRF2, the endogenous antioxidant regulator, might provide therapeutic benefits. Dihydrotanshinone-I (DT) is an active component in Salvia miltiorrhiza with NRF2 induction potency. This study seeks to validate functional links between NRF2 and cardioprotection of DT and to investigate the molecular mechanism particularly emphasizing on NRF2 cytoplasmic/nuclear translocation. DT potently induced NRF2 nuclear accumulation, ameliorating post-reperfusion injuries via redox alterations. Abrogated cardioprotection in NRF2-deficient mice and cardiomyocytes strongly supports NRF2-dependent cardioprotection of DT. Mechanistically, DT phosphorylated NRF2 at Ser40, rendering its nuclear-import by dissociating from KEAP1 and inhibiting degradation. Importantly, we identified PKC-δ-(Thr505) phosphorylation as primary upstream event triggering NRF2-(Ser40) phosphorylation. Knockdown of PKC-δ dramatically retained NRF2 in cytoplasm, convincing its pivotal role in mediating NRF2 nuclear-import. NRF2 activity was further enhanced by activated PKB/GSK-3β signaling via nuclear-export signal blockage independent of PKC-δ activation. By demonstrating independent modulation of PKC-δ and PKB/GSK-3β/Fyn signaling, we highlight the ability of DT to exploit both nuclear import and export regulation of NRF2 in treating reperfusion injury harboring redox homeostasis alterations. Coactivation of PKC and PKB phenocopied cardioprotection of DT in vitro and in vivo, further supporting the potential applicability of this rationale. Graphical abstract

Relationship between clearing heat and cooling blood and regulating blood redox homeostasis of shikonin based on blood heat syndrome mice model / 中草药

Objective: To explore the relationship between clearing heat and cooling blood of shikonin (SK) and regulation of blood redox homeostasis in blood-heat syndrome mice model induced by active yeast. Methods: Mice were randomly divided into control group, model group, SK (10 mg/kg) group, aspirin positive (200 mg/kg) group, L-buthionine sulfoximine (BSO, 600 mg/kg) group, N-acetyl-L-cysteine (NAC, 400 mg/kg) group, BSO combined with SK group, NAC combined with SK group. Mice were sc with 0.2 g/mL active yeast (10 mL/kg) on the neck, mice were ip SK at 0.5 h, ig Asp at 8 h, ip BSO and NAC before the beginning of the experiment (twice a day for one week). The rectal temperature (tR), general activity, metabolism, coagulation, and blood cell counting were determined. The levels of GSH and GSSG were determined by OPA assay. Results: Compared with the control group, tR of mice was significantly increased at 4 h (P < 0.05) and reached (38.07 ± 0.11)℃ at 10 h in model group; Irritability, redder lips, inclined to drinking, reduced carbon powder propelling rate, decreased pellet moisture capacity and prolonged coagulation time were observed (P < 0.05); RBC and inflammatory cells infiltrated were observed in lung tissue sections; The levels of LPO and MDA in serum were significantly increased, the activity of SOD was decreased, GSH/GSSG was decreased (P < 0.05). Compared with model group, tR of mice was significantly reduced and reached (37.51 ± 0.12)℃ at 10 h in SK group; The symptoms were significantly attenuated; The level of LPO and MDA in serum were decreased; The activity of SOD and GSH/GSSG ratio were increased (P < 0.05). BSO significantly reduced the GSH/GSSG ratio (P < 0.05), reduced the effect of SK on blood-heat syndrome mice model. NAC increased the level of GSH in serum and GSH/GSSG ratio (P < 0.05), enhanced the SK treatment effect. Conclusion: SK can attenuate hyperpyrexia, hemorrhage and congestion, oxidative damage in blood-heat syndrome mice model by regulating the blood redox homeostasis, and thereby the effect of clearing heat and cooling blood work.

Oxidative stress as a possible pathogenic cofactor of post-menopausal osteoporosis: Existing evidence in support of the axis oestrogen deficiency-redox imbalance-bone loss

Post-menopausal osteoporosis (PO) is one of the major health issues associated with menopause-related oestrogen withdrawal. Despite the intense research and the relevant progress achieved in the last two decades, the pathogenic mechanism underlying PO is still poorly understood. As a consequence of this gap in the knowledge, such disorder and the related complications are still difficult to be effectively prevented. A wealth of experimental and epidemiological/clinical evidence suggests that the endocrine change associated to menopausal transition might lead to a derangement of redox homeostasis, that is, the prelude to the health-threaten condition of oxidative stress (OxS). In turn, this (bio)chemical stress has been widely hypothesized to contribute, most likely in synergy with inflammation, to the development of menopause-related diseases, including PO. The main aim of this review is to discuss the current literature evidence on the association between post-menopausal oestrogen withdrawal, OxS and PO. It is also aimed to provide a critical overview of the most significant epidemiological studies on the effects of dietary antioxidants on bone health and to devise a strategy to overcome the limitations emerged and controversial results.

Targeting Glutamine Metabolism for Cancer Treatment

Rapidly proliferating cancer cells require energy and cellular building blocks for their growth and ability to maintain redox balance. Many studies have focused on understanding how cancer cells adapt their nutrient metabolism to meet the high demand of anabolism required for proliferation and maintaining redox balance. Glutamine, the most abundant amino acid in plasma, is a well-known nutrient used by cancer cells to increase proliferation as well as survival under metabolic stress conditions. In this review, we provide an overview of the role of glutamine metabolism in cancer cell survival and growth and highlight the mechanisms by which glutamine metabolism affects cancer cell signaling. Furthermore, we summarize the potential therapeutic approaches of targeting glutamine metabolism for the treatment of numerous types of cancer.

Regulation of multidrug resistance by microRNAs in anti-cancer therapy

Multidrug resistance (MDR) remains a major clinical obstacle to successful cancer treatment. Although diverse mechanisms of MDR have been well elucidated, such as dysregulation of drugs transporters, defects of apoptosis and autophagy machinery, alterations of drug metabolism and drug targets, disrupti on of redox homeostasis, the exact mechanisms of MDR in a specific cancer patient and the cross-talk among these different mechanisms and how they are regulated are poorly understood. MicroRNAs (miRNAs) are a new class of small noncoding RNAs that could control the global activity of the cell by post-transcriptionally regulating a large variety of target genes and proteins expression. Accumulating evidence shows that miRNAs play a key regulatory role in MDR through modulating various drug resistant mechanisms mentioned above, thereby holding much promise for developing novel and more effective individualized therapies for cancer treatment. This review summarizes the various MDR mechanisms and mainly focuses on the role of miRNAs in regulating MDR in cancer treatment.

Pulmonary toxicity of single-wall carbon nanotubes and its oxidative stress mechanism / 第二军医大学学报

Objective To systematically study the pulmonary toxicity of single-wall carbon nanotubes (SWCNTs) and to explore the related cytotoxicity mechanism, so as to provide a theoretical basis for the safe productionandapplication of SWCNTs. Methods A549 cells were cultured in the media containing 0, 25, 50, 100, 150, and 200 μg/mL SWCNTs for 24 h, and then the cell viability and degree of cell membrane damage were assessed by CCK-8 and lactate dehydrogenase (LDH) release assay kit, respectively; the ultrastructural alteration of A549 cells was detected by transmission electron microscope (TEM). The oxidative stress response was evaluated by assessing reactive oxygen species (ROS), glutathione (GSH) and superoxide dismutase (SOD). The rats were exposed to SWCNTs by intratracheal inhalation, and then the animals were sacrificed 3 days later and the pathological sections of lung tissue were examined. Results SWCNTs showed considerable toxicity to A549 cells, decreasing cell viability, causing severe damage of cell membrane and ultrastructure, increasing the intracellular ROS level, and decreasing GSH content and SOD activity. It was found that oxidative stress is the main mechanism of SWCNTs toxicity on A549 cells. In vivo toxicity results showed that SWCNTs accumulated in the lung tissue # causing alveolar wall edema. Conclusion In vitro and in vivo toxicity results have found that SWCNTs possess a significant pulmonary toxicity # with its main toxicity mechanismbeing oxidative stress.

Up-regulation of Nrf2 pathway and intervention of intracellular redox homeostasis in shikonin-induced A549 cell apoptosis / 中国药理学通报

Aim To investigate the roles of intracellu-lar reactive oxygen species ( ROS ) and Nrf2 pathway in shikonin-induced A549 cell apoptosis. Methods The cytotoxicity was analyzed by MTT assay. The ap-optosis of A549 cells was analyzed by both cellular morphological and biochemical methods. The relative changes of the redox marks ( ROS/GSH) were studied by fluorescence assay in the shikonin-treated A549 cells in accompany with the changes of the intracellular redox homeostasis by GSH/GSSG ratio. ROS inhibitor was also employed in the treatment to find the role of ROS in shikonin-induced A549 cell apoptosis. Real-time PCR analysis and ELISA assay were performed as well to determine the role of Nrf2 pathway in the shiko-nin-induced A549 cell apoptosis. Results The IC50 of shikonin on A549 cells was 3. 2 mg·L-1 . The cellu-lar redox homeostasis shifted toward oxidation signifi-cantly in shikonin treatment in a time-dependent man-ner. The expression of the Nrf2 pathway related genes was up-regulated by shikonin ( 3 . 2 mg · L-1 , 8 h ) . The expression of the anti-apoptotic genes was down-regulated , and proapoptotic genes were up-regulated by shikonin (3. 2 mg·L-1, 24h). Futhermore, the inhi-bition of intracellular ROS alleviated the cytotoxicity of shikonin in A549 cells. Conclusion The critical role of shikonin-induced redox imblance in A549 cell, coped with the secondary produced ROS and Nrf2 path-way antioxidants, result in A549 cell apoptosis.