scholarly journals Metabolic stress is a primary pathogenic event in transgenic Caenorhabditis elegans expressing pan-neuronal human amyloid beta

2019 ◽  
Author(s):  
Emelyne Teo ◽  
Sudharshan Ravi ◽  
Diogo Barardo ◽  
Hyung-Seok Kim ◽  
Sheng Fong ◽  
...  

AbstractAlzheimer’s disease (AD) is the most common neurodegenerative disease affecting the elderly worldwide. Mitochondrial dysfunction has been proposed as a key event in the etiology of AD. We have previously modeled amyloid-beta (Aβ)-induced mitochondrial dysfunction in a transgenic Caenorhabditis elegans strain by expressing human Aβ peptide specifically in neurons (GRU102). Here, we focus on a deeper analysis of these metabolic changes associated with Aβ-induced mitochondrial dysfunction. Integrating metabolomics, transcriptomics, biochemical studies and computational modeling, we identify alterations in Tricarboxylic Acid (TCA) cycle metabolism following even low-level Aβ expression. In particular, GRU102 show reduced activity of a rate-limiting TCA cycle enzyme, alpha-ketoglutarate dehydrogenase. These defects are associated with elevation of protein carbonyl content specifically in mitochondria. Importantly, metabolic failure occurs before any significant increase in global protein aggregate is detectable. Treatment with an antidiabetes drug, Metformin, reverses Aβ-induced metabolic defects, reduces protein aggregation and normalizes the lifespan of GRU102. Our results point to metabolic dysfunction as an early and causative event in AD pathology and a promising target for intervention.

eLife ◽  
2019 ◽  
Vol 8 ◽  
Author(s):  
Emelyne Teo ◽  
Sudharshan Ravi ◽  
Diogo Barardo ◽  
Hyung-Seok Kim ◽  
Sheng Fong ◽  
...  

Alzheimer’s disease (AD) is the most common neurodegenerative disease affecting the elderly worldwide. Mitochondrial dysfunction has been proposed as a key event in the etiology of AD. We have previously modeled amyloid-beta (Aβ)-induced mitochondrial dysfunction in a transgenic Caenorhabditis elegans strain by expressing human Aβ peptide specifically in neurons (GRU102). Here, we focus on the deeper metabolic changes associated with this Aβ-induced mitochondrial dysfunction. Integrating metabolomics, transcriptomics and computational modeling, we identify alterations in Tricarboxylic Acid (TCA) cycle metabolism following even low-level Aβ expression. In particular, GRU102 showed reduced activity of a rate-limiting TCA cycle enzyme, alpha-ketoglutarate dehydrogenase. These defects were associated with elevation of protein carbonyl content specifically in mitochondria. Importantly, metabolic failure occurred before any significant increase in global protein aggregate was detectable. Treatment with an anti-diabetes drug, Metformin, reversed Aβ-induced metabolic defects, reduced protein aggregation and normalized lifespan of GRU102. Our results point to metabolic dysfunction as an early and causative event in Aβ-induced pathology and a promising target for intervention.


2020 ◽  
Vol 16 ◽  
Author(s):  
Anupama Sharma ◽  
Renu Bist ◽  
Hemant Pareek

Background:: Current study evaluated the protective potential of quercetin against lindane induced toxicity in mice brain. For investigation, mice were allocated into four groups; First group was control. Second group was administered with oral dose of lindane (25 mg/kg bw) for 4 consecutive days. Third group was exposed to quercetin (40 mg/kg bw) and in fourth group, quercetin was administered 1 hour prior to the exposure of lindane. Objective:: Two major objectives were decided for study. First was to create lesions in the brain by lindane and; second was to evaluate the neuroprotective potential of quercetin. Methods:: To study oxidative responses, level of thiobarbituric acid reactive substances (TBARS), protein carbonyl content (PCC), reduced glutathione (GSH), superoxide dismutase (SOD), Catalase (CAT), and glutathione peroxidase (GPx) were measured in brain homogenates. Three key step regulating enzymes of tricarboxylic acid (TCA) cycle viz citrate synthase (CS), pyruvate dehydrogenase (PDH) and fumarase were also assayed. Results:: Lindane treatment significantly enhanced the levels of TBARS (P<0.001),PCC (P<0.001), GPx (P<0.001), SOD (P<0.05), PDH (P<0.05) and fumarase (P<0.001) in brains of mice compared to control. Meanwhile, it alleviated GSH, CAT and CS (P<0.05) activity. Conclusion:: Pretreatment with quercetin in lindane treated group not only restored, previously altered biochemical parameters after lindane treatment and also significantly improved them too which suggests that quercetin is not only invulnerable rather neuroprotective against lindane intoxication.


2020 ◽  
Vol 21 (16) ◽  
pp. 5598 ◽  
Author(s):  
Yongde Luo ◽  
Jianjia Ma ◽  
Weiqin Lu

As an essential organelle in nucleated eukaryotic cells, mitochondria play a central role in energy metabolism, maintenance of redox balance, and regulation of apoptosis. Mitochondrial dysfunction, either due to the TCA cycle enzyme defects, mitochondrial DNA genetic mutations, defective mitochondrial electron transport chain, oxidative stress, or aberrant oncogene and tumor suppressor signaling, has been observed in a wide spectrum of human cancers. In this review, we summarize mitochondrial dysfunction induced by these alterations that promote human cancers.


2019 ◽  
Vol 2 (2) ◽  
pp. 1-21 ◽  
Author(s):  
Elina Mitra ◽  
Bharati Bhattacharjee ◽  
Palash Kumar Pal ◽  
Arnab Kumar Ghosh ◽  
Sanatan Mishra ◽  
...  

Cadmium (Cd) is a notorious environmental pollutant known for its wide range of toxicities to organisms. Thus, the present study is designed to examine whether melatonin, a potent antioxidant, protects against Cd-induced oxidative damage in the heart, liver and kidney of rats. Cd treatment at a dose of 0.44 mg/kg for 15 days caused severe damage in all these organs. These included significantly increased activities of SGPT, SGOT, lactate dehydrogenase- 1 and 5 and ALP and levels of total lactate, creatinine, lipid peroxidation, protein carbonyl content and reduced glutathione while the activities of superoxide dismutases, catalase, glutathione peroxidase, glutathione reductase and glutathione-S-transferase along with mitochondrial pyruvate dehydrogenase, isocitrate dehydrogenase, α-keto glutarate dehydrogenase, succinate dehydrogenase, NADH-cytochrome-c-oxidoreductase and cytochrome-c-oxidase were significantly reduced by Cd. However, if melatonin was given orally 30 min before Cd injection, all these alterations induced by Cd were significantly preserved by melatonin. Histological observations also demonstrated that Cd exposure caused cellular lesions, promoting necrotic or apoptotic changes. Notably, all these changes were significantly protected by melatonin. The results suggest that melatonin is a beneficial molecule to ameliorate Cd-induced oxidative damage in the heart, liver and kidney tissues of rats with its powerful antioxidant capacity, heavy metal chelating activity and competition of binding sites with Cd to the GSH and catalase.


2010 ◽  
Vol 37 (2) ◽  
pp. 154-160 ◽  
Author(s):  
Ling-Ling LIU ◽  
Bai-Yang SHENG ◽  
Kai GONG ◽  
Nan-Ming ZHAO ◽  
Xiu-Fang ZHANG ◽  
...  

2020 ◽  
Vol 70 (2) ◽  
pp. 227-237
Author(s):  
Eda Güneş

Abstract The aim of the this study was to evaluate the effects of fresh, dried and freeze-dried Centaurea depressa M. Bieb. (Asteraceae) on the oxidant and antioxidant status of the model organism D. melanogaster Meigen (Diptera: Drosophilidae) experimentally. The study was carried out from 2016 to 2019, and plant leaf extracts (0-50 mg/l) were added to insect standard artificial diets. The total protein, protein carbonyl content and glutathione-S-transferase, superoxide dismutase and catalase activities were quantified at the insect’s third larval stage. Our data showed that protein carbonyl content varied from 2.70 nmol/mg protein in the control group to 59.11 nmol/mg protein in the group fed with fresh leaf extract signifying induction of oxidative stress. All extracts increased the levels of all antioxidant enzymes and decreased the amounts of total protein. Meanwhile, the group fed with the freeze-dried extract showed no significant difference in the levels of total protein and protein carbonyl content except at the 50 mg/l concentration of the extract. Moreover, this group had superoxide dismutase and catalase activities 4 to 5 times higher than in the control group. In conclusion, induction of oxidative stress indicates that the fresh form of C. depressa leaves may have potential as a natural pesticide, whereas induction of endogenous antioxidant enzymes by the freeze-dried extract suggest its potential as an antioxidant.


Blood ◽  
2021 ◽  
Author(s):  
Alexandra Sipol ◽  
Erik Hameister ◽  
Busheng Xue ◽  
Julia Hofstetter ◽  
Maxim Barenboim ◽  
...  

Cancer cells are in most instances characterized by rapid proliferation and uncontrolled cell division. Hence, they must adapt to proliferation-induced metabolic stress through intrinsic or acquired anti-metabolic stress responses to maintain homeostasis and survival. One mechanism to achieve this is to reprogram gene expression in a metabolism-dependent manner. MondoA (also known as MLXIP), a member of the MYC interactome, has been described as an example of such a metabolic sensor. However, the role of MondoA in malignancy is not fully understood and the underlying mechanism in metabolic responses remains elusive. By assessing patient data sets we found that MondoA overexpression is associated with a worse survival in pediatric common acute lymphoblastic leukemia (B-ALL). Using CRISPR/Cas9 and RNA interference approaches, we observed that MondoA depletion reduces transformational capacity of B-ALL cells in vitro and dramatically inhibits malignant potential in an in vivo mouse model. Interestingly, reduced expression of MondoA in patient data sets correlated with enrichment in metabolic pathways. The loss of MondoA correlated with increased tricarboxylic acid (TCA) cycle activity. Mechanistically, MondoA senses metabolic stress in B-ALL cells by restricting oxidative phosphorylation through reduced PDH activity. Glutamine starvation conditions greatly enhance this effect and highlight the inability to mitigate metabolic stress upon loss of MondoA in B-ALL. Our findings give a novel insight into the function of MondoA in pediatric B-ALL and support the notion that MondoA inhibition in this entity offers a therapeutic opportunity and should be further explored.


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