Ketone bodies, stress response, and redox homeostasis.
Ontology highlight
ABSTRACT:
SUBMITTER: Rojas-Morales P
PROVIDER: S-EPMC6911969 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Diets characterized by increased blood levels of ketone bodies can protect the brain against a variety of acute and chronic neurological diseases. Moreover, ketone bodies are neuroprotective in many in vitro models of neurological injury. The underlying mechanisms remain unknown however. Recently, we have shown that ketone bodies do not only decrease neuronal injury and death but also protect long-term potentiation in acute hippocampal slices exposed to oxidative stress in the form of exogenous hydrogen peroxide. Elucidating the mechanisms behind the effects of ketone bodies on neuronal survival and function will undoubtedly lead to the development of novel neuroprotective treatments. Our aim is to determine acute changes in gene expression of CA1 pyramidal neurons exposed to various duration of the ketone bodies acetoacetate and beta-hydroxybutyrate. CA1 hippocampal pyramidal neurons exposed to oxidative stress do not display any long-term potention following burst stimulation of Schaffer collaterals. Incubation with the ketone bodies acetoacetate and beta-hydroxybutyrate for at least 20 min prior to hydrogen peroxide application restores long-term potentiation to control levels. We hypothesize that the neuroprotective effects of ketone bodies are mediated by changes in gene expression. Acute hippocampal slices (400 microns in thickness) were obtained from 4 week-old rats and exposed to acetoacetate and beta-hydroxybutyrate (1 mM each) for 1 h and 6 h. A control group was incubated in artificial cerebrospinal fluid only. After treatment, the hippocampal slices were used immediately for RNA isolation. Isolated RNA was sent for analysis. Each sample sent for analysis included tissue from 7 separate animals. Hybridization to an Affymetrix array is being performed 3 times for each experimental condition.
2008-06-15 | E-GEOD-7323 | biostudies-arrayexpress
Project description:Diets characterized by increased blood levels of ketone bodies can protect the brain against a variety of acute and chronic neurological diseases. Moreover, ketone bodies are neuroprotective in many in vitro models of neurological injury. The underlying mechanisms remain unknown however. Recently, we have shown that ketone bodies do not only decrease neuronal injury and death but also protect long-term potentiation in acute hippocampal slices exposed to oxidative stress in the form of exogenous hydrogen peroxide. Elucidating the mechanisms behind the effects of ketone bodies on neuronal survival and function will undoubtedly lead to the development of novel neuroprotective treatments. Our aim is to determine acute changes in gene expression of CA1 pyramidal neurons exposed to various duration of the ketone bodies acetoacetate and beta-hydroxybutyrate. CA1 hippocampal pyramidal neurons exposed to oxidative stress do not display any long-term potention following burst stimulation of Schaffer collaterals. Incubation with the ketone bodies acetoacetate and beta-hydroxybutyrate for at least 20 min prior to hydrogen peroxide application restores long-term potentiation to control levels. We hypothesize that the neuroprotective effects of ketone bodies are mediated by changes in gene expression. Acute hippocampal slices (400 microns in thickness) were obtained from 4 week-old rats and exposed to acetoacetate and beta-hydroxybutyrate (1 mM each) for 1 h and 6 h. A control group was incubated in artificial cerebrospinal fluid only. After treatment, the hippocampal slices were used immediately for RNA isolation. Isolated RNA was sent for analysis. Each sample sent for analysis included tissue from 7 separate animals. Hybridization to an Affymetrix array is being performed 3 times for each experimental condition. Keywords: dose response
2007-03-20 | GSE7323 | GEO
Project description:NRF2 is a transcription factor responsible for antioxidant stress responses that is usually regulated in a redox-dependent manner. p62 bodies formed by liquid-liquid phase separation contain Ser349-phosphorylated p62, which participates in the redox-independent activation of NRF2. However, the regulatory mechanism and physiological significance of p62 phosphorylation remain unclear. Here, we identify ULK1 as a kinase responsible for the phosphorylation of p62. ULK1 co-localizes with p62 bodies, directly interacting with p62. ULK1-dependent phosphorylation of p62 allows KEAP1 to be retained within p62 bodies, thus activating NRF2. p62S351E/+ mice are phosphomimetic knock-in mice in which Ser351, corresponding to human Ser349, is replaced by Glu. These mice, but not their phosphodefective p62S351A/S351A counterparts, exhibit NRF2 hyperactivation and growth retardation. This retardation is caused by malnutrition and dehydration due to obstruction of the esophagus and forestomach secondary to hyperkeratosis, a phenotype also observed in systemic Keap1-knockout mice. Our results expand our understanding of the physiological importance of the redox-independent NRF2 activation pathway and provide new insights into the role of phase separation in this process.
| S-SCDT-10_15252-EMBJ_2022113349 | biostudies-other
Project description:BackgroundCancer Anorexia Cachexia Syndrome (CACS) is a distinct atrophy disease negatively influencing multiple aspects of clinical care and patient quality of life. Although it directly causes 20% of all cancer-related deaths, there are currently no model systems that encompass the entire multifaceted syndrome, nor are there any effective therapeutic treatments.MethodsA novel model of systemic metastasis was evaluated for the comprehensive CACS (metastasis, skeletal muscle and adipose tissue wasting, inflammation, anorexia, anemia, elevated protein breakdown, hypoalbuminemia, and metabolic derangement) in both males and females. Ex vivo skeletal muscle analysis was utilized to determine ubiquitin proteasome degradation pathway activation. A novel ketone diester (R/S 1,3-Butanediol Acetoacetate Diester) was assessed in multifaceted catabolic environments to determine anti-atrophy efficacy.ResultsHere, we show that the VM-M3 mouse model of systemic metastasis demonstrates a novel, immunocompetent, logistically feasible, repeatable phenotype with progressive tumor growth, spontaneous metastatic spread, and the full multifaceted CACS with sex dimorphisms across tissue wasting. We also demonstrate that the ubiquitin proteasome degradation pathway was significantly upregulated in association with reduced insulin-like growth factor-1/insulin and increased FOXO3a activation, but not tumor necrosis factor-α-induced nuclear factor-kappa B activation, driving skeletal muscle atrophy. Additionally, we show that R/S 1,3-Butanediol Acetoacetate Diester administration shifted systemic metabolism, attenuated tumor burden indices, reduced atrophy/catabolism and mitigated comorbid symptoms in both CACS and cancer-independent atrophy environments.ConclusionsOur findings suggest the ketone diester attenuates multifactorial CACS skeletal muscle atrophy and inflammation-induced catabolism, demonstrating anti-catabolic effects of ketone bodies in multifactorial atrophy.
| S-EPMC7432582 | biostudies-literature
Project description:Diatoms are ubiquitous marine photosynthetic eukaryotes that are responsible for about 20% of global photosynthesis. Nevertheless, little is known about the redox-based mechanisms that mediate diatom sensing and acclimation to environmental stress. Here we used a redox-sensitive green fluorescent protein sensor targeted to various subcellular organelles in the marine diatom Phaeodactylum tricornutum, to map the spatial and temporal oxidation patterns in response to environmental stresses. Specific organelle oxidation patterns were found in response to various stress conditions such as oxidative stress, nutrient limitation and exposure to diatom-derived infochemicals. We found a strong correlation between the mitochondrial glutathione (GSH) redox potential (EGSH) and subsequent induction of cell death in response to the diatom-derived unsaturated aldehyde 2E,4E/Z-decadienal (DD), and a volatile halocarbon (BrCN) that mediate trophic-level interactions in marine diatoms. Induction of cell death in response to DD was mediated by oxidation of mitochondrial EGSH and was reversible by application of GSH only within a narrow time frame. We found that cell fate can be accurately predicted by a distinct life-death threshold of mitochondrial EGSH (-335?mV). We propose that compartmentalized redox-based signaling can integrate the input of diverse environmental cues and will determine cell fate decisions as part of algal acclimation to stress conditions.
| S-EPMC4303632 | biostudies-literature
Project description:Severe COVID-19 is characterized by profound CD8+ T-cell dysfunction, which cannot be specifically treated to date. We here investigate whether metabolic CD8+ T-cell reprogramming by ketone bodies could be a promising strategy to overcome the immunoparalysis in COVID-19 patients. This approach was triggered by our recent pioneering study, which has provided evidence that CD8+ T-cell capacity in healthy subjects could be significantly empowered by a Ketogenic Diet. These improvements were achieved by immunometabolic rewiring toward oxidative phosphorylation. We here report similar strengthening of CD8+ T cells obtained from severely diseased COVID-19 patients: Flow cytometry and ELISA revealed elevated cytokine expression and secretion (up to + 24%) upon ketone treatment and enhanced cell lysis capacity (+ 21%). Metabolic analyses using Seahorse technology revealed upregulated mitochondrial respiratory chain activity (+ 25%), enabling both superior energy supply (+ 44%) and higher mitochondrial reactive oxygen species signaling. These beneficial effects of ketones might represent evolutionary conserved mechanisms to strengthen human immunity. Our findings pave the road for metabolic treatment studies in COVID-19.
| S-EPMC9243504 | biostudies-literature
Project description:The circadian system has endowed animals with the ability to anticipate recurring food availability at particular times of day. As daily food anticipation (FA) is independent of the suprachiasmatic nuclei, the central pacemaker of the circadian system, questions arise of where FA signals originate and what role components of the circadian clock might play. Here we show that liver-specific deletion of Per2 in mice abolishes FA, an effect that is rescued by viral overexpression of Per2 in the liver. RNA sequencing indicates that Per2 regulates ?-hydroxybutyrate (?OHB) production to induce FA leading to the conclusion that liver Per2 is important for this process. Unexpectedly, we show that FA originates in the liver and not in the brain. However, manifestation of FA involves processing of the liver-derived ?OHB signal in the brain, indicating that the food-entrainable oscillator is not located in a single tissue but is of systemic nature.
| S-EPMC4742855 | biostudies-literature
Project description:BACKGROUND:Significant evidence indicates that the failing heart is energy starved. During the development of heart failure, the capacity of the heart to utilize fatty acids, the chief fuel, is diminished. Identification of alternate pathways for myocardial fuel oxidation could unveil novel strategies to treat heart failure. METHODS AND RESULTS:Quantitative mitochondrial proteomics was used to identify energy metabolic derangements that occur during the development of cardiac hypertrophy and heart failure in well-defined mouse models. As expected, the amounts of proteins involved in fatty acid utilization were downregulated in myocardial samples from the failing heart. Conversely, expression of ?-hydroxybutyrate dehydrogenase 1, a key enzyme in the ketone oxidation pathway, was increased in the heart failure samples. Studies of relative oxidation in an isolated heart preparation using ex vivo nuclear magnetic resonance combined with targeted quantitative myocardial metabolomic profiling using mass spectrometry revealed that the hypertrophied and failing heart shifts to oxidizing ketone bodies as a fuel source in the context of reduced capacity to oxidize fatty acids. Distinct myocardial metabolomic signatures of ketone oxidation were identified. CONCLUSIONS:These results indicate that the hypertrophied and failing heart shifts to ketone bodies as a significant fuel source for oxidative ATP production. Specific metabolite biosignatures of in vivo cardiac ketone utilization were identified. Future studies aimed at determining whether this fuel shift is adaptive or maladaptive could unveil new therapeutic strategies for heart failure.
| S-EPMC4766035 | biostudies-literature
Project description:Respiratory viral infections remain a scourge, with seasonal influenza infecting millions and killing many thousands annually and viral pandemics, such as COVID-19, recurring every decade. Age, cardiovascular disease, and diabetes mellitus are risk factors for severe disease and death from viral infection. Immunometabolic therapies for these populations hold promise to reduce the risks of death and disability. Such interventions have pleiotropic effects that might not only target the virus itself but also enhance supportive care to reduce cardiopulmonary complications, improve cognitive resilience, and facilitate functional recovery. Ketone bodies are endogenous metabolites that maintain cellular energy but also feature drug-like signaling activities that affect immune activity, metabolism, and epigenetics. Here, we provide an overview of ketone body biology relevant to respiratory viral infection, focusing on influenza A and severe acute respiratory syndrome (SARS)-CoV-2, and discuss the opportunities, risks, and research gaps in the study of exogenous ketone bodies as novel immunometabolic interventions in these diseases.
| S-EPMC7362813 | biostudies-literature
Project description:BackgroundAberrant energy metabolism is a hallmark of cancer. To fulfill the increased energy requirements, tumor cells secrete cytokines/factors inducing muscle and fat degradation in cancer patients, a condition known as cancer cachexia. It accounts for nearly 20% of all cancer-related deaths. However, the mechanistic basis of cancer cachexia and therapies targeting cancer cachexia thus far remain elusive. A ketogenic diet, a high-fat and low-carbohydrate diet that elevates circulating levels of ketone bodies (i.e., acetoacetate, β-hydroxybutyrate, and acetone), serves as an alternative energy source. It has also been proposed that a ketogenic diet leads to systemic metabolic changes. Keeping in view the significant role of metabolic alterations in cancer, we hypothesized that a ketogenic diet may diminish glycolytic flux in tumor cells to alleviate cachexia syndrome and, hence, may provide an efficient therapeutic strategy.ResultsWe observed reduced glycolytic flux in tumor cells upon treatment with ketone bodies. Ketone bodies also diminished glutamine uptake, overall ATP content, and survival in multiple pancreatic cancer cell lines, while inducing apoptosis. A decrease in levels of c-Myc, a metabolic master regulator, and its recruitment on glycolytic gene promoters, was in part responsible for the metabolic phenotype in tumor cells. Ketone body-induced intracellular metabolomic reprogramming in pancreatic cancer cells also leads to a significantly diminished cachexia in cell line models. Our mouse orthotopic xenograft models further confirmed the effect of a ketogenic diet in diminishing tumor growth and cachexia.ConclusionsThus, our studies demonstrate that the cachectic phenotype is in part due to metabolic alterations in tumor cells, which can be reverted by a ketogenic diet, causing reduced tumor growth and inhibition of muscle and body weight loss.
| S-EPMC4165433 | biostudies-literature