Abscisic acid-mediated guard cell metabolism regulation.

Abscisic acid (ABA) is crucial for plant water deficit (WD) acclimation, but how the interplay between ABA and guard cell (GC) metabolism aids plant WD acclimation remains unclear. Here, we investigated how ABA regulates GC metabolism and how this contributes to plant WD acclimation using tomato wild type (WT) and the ABA-deficient sitiens mutant. These genotypes were characterized at physiological, metabolic, and transcriptional levels under recurring WD periods and were used to perform a13C-glucose labelling experiment using isolated guard cells following exogenously applied ABA. ABA deficiency altered the level of sugars and organic acids in GCs in both irrigated and WD plants and the dynamic of accumulation/degradation of these compounds in GCs during the dark-to-light transition. WD-induced metabolic changes were more pronounced in sitiens than WT GCs. Results from the 13C-labelling experiment indicate that ABA is required for the glycolytic fluxes toward malate and acts as a negative regulator of a putative sucrose substrate cycle. The expression of key ABA-biosynthetic genes was higher in WT than in sitiens GCs after two cycles of WD. Additionally, the intrinsic leaf water use efficiency increased only in WT after the second WD cycle, compared to sitiens. Our results highlight that ABA deficiency disrupts the homeostasis of GC primary metabolism and the WD memory, negatively affecting plant WD acclimation. Our study demonstrates which metabolic pathways are activated by WD and/or regulated by ABA in GCs, which improves our understanding of plant WD acclimation, with clear consequences for plant metabolic engineering in the future.

Determination of unbound platinum concentrations in human plasma using ultrafiltration and precipitation methods.

Quantification of the unbound portion of platinum (Pt) in human plasma is important for assessing the pharmacokinetics of the chemotherapeutic drug cisplatin. In this study, we sought to compare the recovery of unbound Pt using Nanosep® filters to 1) traditional filters (Centrifree®, Centrisart®, Amicon®) or trichloroacetic acid (TCA) protein precipitation, and 2) unbound, bound, and total Pt concentrations in clinical specimens. For the tested filters, the impact of 1) molecular weight cut-offs, 2) centrifugation force, and 3) total Pt concentration on Pt binding in human plasma was evaluated. Pt was quantified using inductively coupled-plasma mass spectrometry. In human plasma spiked with 0.9 µg/mL Pt, the percent of unbound Pt increased at higher centrifugation speeds. By comparison, the percent of unbound Pt was highest (42.1%) following TCA protein precipitation. When total Pt was ≤0.9 µg/mL, unbound Pt (∼20-30%) was consistent across filters. Conversely, when plasma was spiked with Pt exceeding 0.9 µg/mL, the percent of unbound Pt increased from 36.5 to 48% using ultrafiltration, compared to 63.4% to 79% with TCA precipitation. In patients receiving cisplatin-containing chemotherapy, the fraction of unbound Pt at concentrations exceeding 0.9 µg/mL ranged between 35 and 90%. Moreover, the unbound fraction of Pt in plasma correlated with the concentration of unbound (R2 = 0.738) and total Pt (R2 = 0.335). In summary, this study demonstrates that 1) the percent of unbound Pt is influenced by total and unbound Pt levels in vitro and in clinical specimens, and 2) ultrafiltration with Nanosep® filters is a feasible method for quantifying unbound Pt concentrations in human plasma.

Is the TCA cycle malate dehydrogenase-citrate synthase metabolon an illusion?

This review discusses the intriguing yet controversial concept of metabolons, focusing on the malate dehydrogenase-citrate synthase (MDH-CISY) metabolon as a model. Metabolons are multienzyme complexes composed of enzymes that catalyze sequential reactions in metabolic pathways. Metabolons have been proposed to enhance metabolic pathway efficiency by facilitating substrate channeling. However, there is skepticism about the presence of metabolons and their functionality in physiological conditions in vivo. We address the skepticism by reviewing compelling evidence supporting the existence of the MDH-CISY metabolon and highlighting its potential functions in cellular metabolism. The electrostatic interaction between MDH and CISY and the intermediate oxaloacetate, channeled within the metabolon, has been demonstrated using various experimental techniques, including protein-protein interaction assays, isotope dilution studies, and enzyme coupling assays. Regardless of the wealth of in vitro evidence, further validation is required to elucidate the functionality of MDH-CISY metabolons in living systems using advanced structural and spatial analysis techniques.

Physiology of malate dehydrogenase and how dysregulation leads to disease.

Malate dehydrogenase (MDH) is pivotal in mammalian tissue metabolism, participating in various pathways beyond its classical roles and highlighting its adaptability to cellular demands. This enzyme is involved in maintaining redox balance, lipid synthesis, and glutamine metabolism and supports rapidly proliferating cells' energetic and biosynthetic needs. The involvement of MDH in glutamine metabolism underlines its significance in cell physiology. In contrast, its contribution to lipid metabolism highlights its role in essential biosynthetic processes necessary for cell maintenance and proliferation. The enzyme's regulatory mechanisms, such as post-translational modifications, underscore its complexity and importance in metabolic regulation, positioning MDH as a potential target in metabolic dysregulation. Furthermore, the association of MDH with various pathologies, including cancer and neurological disorders, suggests its involvement in disease progression. The overexpression of MDH isoforms MDH1 and MDH2 in cancers like breast, prostate, and pancreatic ductal adenocarcinoma, alongside structural modifications, implies their critical role in the metabolic adaptation of tumor cells. Additionally, mutations in MDH2 linked to pheochromocytomas, paragangliomas, and other metabolic diseases emphasize MDH's role in metabolic homeostasis. This review spotlights MDH's potential as a biomarker and therapeutic target, advocating for further research into its multifunctional roles and regulatory mechanisms in health and disease.

Impact of therapeutic inhibition of oncogenic cell signaling tyrosine kinase on cell metabolism: in vivo-detectable metabolic biomarkers of inhibition.

BACKGROUND: Inhibition of kinases is the ever-expanding therapeutic approach to various types of cancer. Typically, assessment of the treatment response is accomplished by standard, volumetric imaging procedures, performed weeks to months after the onset of treatment, given the predominantly cytostatic nature of the kinase inhibitors, at least when used as single agents. Therefore, there is a great clinical need to develop new monitoring approaches to detect the response to kinase inhibition much more promptly. Noninvasive 1H magnetic resonance spectroscopy (MRS) can measure in vitro and in vivo concentration of key metabolites which may potentially serve as biomarkers of response to kinase inhibition. METHODS: We employed mantle cell lymphoma (MCL) cell lines demonstrating markedly diverse sensitivity of inhibition of Bruton's tyrosine kinase (BTK) regarding their growth and studied in-depth effects of the inhibition on various aspects of cell metabolism including metabolite synthesis using metabolomics, glucose and oxidative metabolism by Seahorse XF technology, and concentration of index metabolites lactate, alanine, total choline and taurine by 1H MRS. RESULTS: Effective BTK inhibition profoundly suppressed key cell metabolic pathways, foremost pyrimidine and purine synthesis, the citrate (TCA) cycle, glycolysis, and pyruvate and glutamine/alanine metabolism. It also inhibited glycolysis and amino acid-related oxidative metabolism. Finally, it profoundly and quickly decreased concentration of lactate (a product of mainly glycolysis) and alanine (an indicator of amino acid metabolism) and, less universally total choline both in vitro and in vivo, in the MCL xenotransplant model. The decrease correlated directly with the degree of inhibition of lymphoma cell expansion and tumor growth. CONCLUSIONS: Our results indicate that BTK inhibition exerts a broad and profound suppressive effect on cell metabolism and that the affected index metabolites such as lactate, alanine may serve as early, sensitive, and reliable biomarkers of inhibition in lymphoma patients detectable by noninvasive MRS-based imaging method. This kind of imaging-based detection may also be applicable to other kinase inhibitors, as well as diverse lymphoid and non-lymphoid malignancies.

Sex-dependent differences in macaque brain mitochondria.

Mitochondrial bioenergetics in females and males is different. However, whether mitochondria from male and female brains display differences in enzymes of oxidative phosphorylation remains unknown. Therefore, we characterized mitochondrial complexes from the brains of male and female macaques (Macaca mulatta). Cerebral tissue from male macaques exhibits elevated content and activity of mitochondrial complex I (NADH:ubiquinone oxidoreductase) and higher activity of complex II (succinate dehydrogenase) compared to females. No significant differences between sexes were found in the content of α-ketoglutarate dehydrogenase or in the activities of cytochrome c oxidase and F1Fo ATPase. Our results underscore the need for further investigations to elucidate sex-related mitochondrial differences in humans.

Bidirectional modulation of TCA cycle metabolites and anaplerosis by metformin and its combination with SGLT2i.

BACKGROUND: Metformin and sodium-glucose-cotransporter-2 inhibitors (SGLT2i) are cornerstone therapies for managing hyperglycemia in diabetes. However, their detailed impacts on metabolic processes, particularly within the citric acid (TCA) cycle and its anaplerotic pathways, remain unclear. This study investigates the tissue-specific metabolic effects of metformin, both as a monotherapy and in combination with SGLT2i, on the TCA cycle and associated anaplerotic reactions in both mice and humans. METHODS: Metformin-specific metabolic changes were initially identified by comparing metformin-treated diabetic mice (MET) with vehicle-treated db/db mice (VG). These findings were then assessed in two human cohorts (KORA and QBB) and a longitudinal KORA study of metformin-naïve patients with Type 2 Diabetes (T2D). We also compared MET with db/db mice on combination therapy (SGLT2i + MET). Metabolic profiling analyzed 716 metabolites from plasma, liver, and kidney tissues post-treatment, using linear regression and Bonferroni correction for statistical analysis, complemented by pathway analyses to explore the pathophysiological implications. RESULTS: Metformin monotherapy significantly upregulated TCA cycle intermediates such as malate, fumarate, and α-ketoglutarate (α-KG) in plasma, and anaplerotic substrates including hepatic glutamate and renal 2-hydroxyglutarate (2-HG) in diabetic mice. Downregulated hepatic taurine was also observed. The addition of SGLT2i, however, reversed these effects, such as downregulating circulating malate and α-KG, and hepatic glutamate and renal 2-HG, but upregulated hepatic taurine. In human T2D patients on metformin therapy, significant systemic alterations in metabolites were observed, including increased malate but decreased citrulline. The bidirectional modulation of TCA cycle intermediates in mice influenced key anaplerotic pathways linked to glutaminolysis, tumorigenesis, immune regulation, and antioxidative responses. CONCLUSION: This study elucidates the specific metabolic consequences of metformin and SGLT2i on the TCA cycle, reflecting potential impacts on the immune system. Metformin shows promise for its anti-inflammatory properties, while the addition of SGLT2i may provide liver protection in conditions like metabolic dysfunction-associated steatotic liver disease (MASLD). These observations underscore the importance of personalized treatment strategies.

Emergency reflex action drill for traumatic cardiac arrest in a simulated pre-hospital setting; a one-group pre-post intervention study.

BACKGROUND: Emergency Reflex Action Drills (ERADs) are meant to decrease stress-associated cognitive demand in high urgency situations. The aim of this study was to develop and test an ERAD for witnessed traumatic cardiac arrest (TCA), an event in which potentially reversible causes need to be systematically addressed and treated in a short period of time. We hypothesize that this ERAD (the TCA-Drill) helps ground Emergency Medical Services (EMS) nurses in overcoming performance decline during this specific high-pressure situation. METHODS: This was a prospective, experimental one-group pre-post intervention study. Ground EMS nurses participated in a session of four simulated scenarios, with an in-between educational session to teach the TCA-Drill. Scenarios were video recorded, after which adherence and time differences were analyzed. Self-confidence on clinical practice was measured before and after the scenarios. RESULTS: Twelve ground EMS nurses participated in this study. Overall median time to address reversible causes of TCA decreased significantly using the TCA-Drill (132 vs. 110 s; p = 0.030) compared with the conventional ALS strategy. More specifically, participants adhering to the TCA-Drill showed a significantly lower time needed for hemorrhage control (58 vs. 37 s; p = 0.012). Eight of 12 (67 %) ground EMS nurses performed the ERAD without protocol deviations. Reported self-confidence significantly increased on 11 of the 13 surveyed items. CONCLUSIONS: The use of an ERAD for TCA (the TCA-Drill) significantly reduces the time to address reversible causes for TCA without delaying chest compressions in a simulated environment and can be easily taught to ground EMS nurses and increases self-confidence. IMPLICATIONS FOR CLINICAL PRACTICE: The use of an ERAD for TCA (the TCA-Drill can significantly reduce the time to address reversible causes for TCA without delaying chest compression. This drill can be easily taught to ground EMS nurses and increases their self-confidence in addressing TCA-patients.

The association of circulating bioenergetic metabolites with healthy human aging.

Aging is an inevitable and gradual decline in several biological functions. Mitochondrial dysfunction is one of the most important hallmarks of aging. In this context, alterations in metabolites associated with mitochondrial dysfunction may serve as a significant biomarker. This study aimed to investigate the existence of a relationship between the key metabolites involved in bioenergetics metabolism and aging. 53 volunteers ranged 20-85 years participated in the study. We tested the association between different tricarboxylic acid (TCA) cycle metabolites, fatty acid metabolism, and amino acid metabolism with age, sex, body composition, and proxy markers of aging such as walking speed, grip strength and chair test. We found that lactic acid negatively correlated with age while several fatty acid metabolites, such as azelaic, sebacic, and linoleic acids, showed positive correlations with age (p < 0.05). Sex-specific trends, such as glycerol, and dodecanoic acid, were also observed for certain metabolites. Furthermore, citric acid levels were found to have a significant association with physical function and body composition measures. Participants with higher citric acid levels displayed improved performance in physical tests and favorable body composition indices. Additionally, fumaric acid and adipic acid showed positive correlations with fat-free body mass, while sebacic acid was negatively associated with measures of fat mass. These findings underscore the importance of understanding the role of circulating bioenergetics metabolites with age, sex variations, and their potential implications in body composition and physical performance.

Associations between TCA cycle plasma metabolites and fatigue in black females with systemic lupus erythematosus: An untargeted metabolomics pilot study.

OBJECTIVE: In this pilot study, we used untargeted metabolomics to identify biochemical mechanisms or biomarkers potentially underlying SLE-related fatigue. METHODS: Metabolon conducted untargeted metabolomic plasma profiling using ultrahigh performance liquid chromatography/tandem mass spectrometry on plasma samples of 23 Black females with systemic lupus erythematosus (SLE) and 21 no SLE controls. Fatigue phenotypes of general fatigue, physical fatigue, mental fatigue, reduced activity, and reduced motivation were measured with the reliable and valid Multidimensional Fatigue Inventory (MFI). RESULTS: A total of 290 metabolites were significantly different between the SLE and no SLE groups, encompassing metabolites related to glycolysis, TCA cycle activity, heme catabolism, branched chain amino acids, fatty acid metabolism, and steroids. Within the SLE group, controlling for age and co-morbidities, TCA cycle metabolites of alpha-ketoglutarate (AKG) and succinate were statistically significantly associated (p < .05) with physical and general fatigue. CONCLUSION: While pervasive perturbations in the entire TCA cycle have been implicated as a potential mechanism for fatigue, our results suggest individual metabolites of AKG and succinate may be potential biomarkers or targets of intervention for fatigue symptom management in SLE. Additionally, perturbations in heme metabolism in the SLE group provide additional insights into mechanisms that promote systemic inflammation.

Ovarian aging: energy metabolism of oocytes.

In women who are getting older, the quantity and quality of their follicles or oocytes and decline. This is characterized by decreased ovarian reserve function (DOR), fewer remaining oocytes, and lower quality oocytes. As more women choose to delay childbirth, the decline in fertility associated with age has become a significant concern for modern women. The decline in oocyte quality is a key indicator of ovarian aging. Many studies suggest that age-related changes in oocyte energy metabolism may impact oocyte quality. Changes in oocyte energy metabolism affect adenosine 5'-triphosphate (ATP) production, but how related products and proteins influence oocyte quality remains largely unknown. This review focuses on oocyte metabolism in age-related ovarian aging and its potential impact on oocyte quality, as well as therapeutic strategies that may partially influence oocyte metabolism. This research aims to enhance our understanding of age-related changes in oocyte energy metabolism, and the identification of biomarkers and treatment methods.

The cardiovascular safety of tricyclic antidepressants in overdose and in clinical use.

Tricyclic antidepressants (TCAs) remain widely prescribed for depression and many other conditions. There may be important differences between individual TCA in regard to their overdose toxicity and their cardiac toxicity in clinical use. We conducted a systematic review to compare the toxicity of individual TCA in overdose and the risk of serious adverse cardiac events occurring with therapeutic doses. We used the fatal toxicity index (FTI) and case fatality ratio as markers of fatality in overdose, and hazard ratios or odds ratios for the risk of cardiovascular adverse events during normal clinical use. In all, 30 reports of mortality in overdose and 14 observational studies assessing the risk of cardiovascular adverse events in clinical use were included. FTI values were of the same order of magnitude (101-102) for all TCAs except lofepramine. Desipramine appears to be somewhat more likely than other TCAs to lead to death in overdose. Amitriptyline, clomipramine, dothiepin/dosulepin, doxepin, trimipramine and imipramine showed broadly similar toxicity and were usually reported to be less toxic than desipramine. Data on nortriptyline were contradictory. Lofepramine had the lowest risk of death in overdose. The rank order of overdose toxicity was broadly consistent between different FTI definitions and between markers used. With respect to the risk of cardiovascular events at clinically relevant exposure, amitriptyline, nortriptyline and lofepramine were associated with a greater risk of in-use cardiotoxicity. All measures of overdose toxicity were subject to external influences and confounding. The continued use of TCAs in depression and other conditions should be minimized when considering their undoubted toxicity in overdose and possible toxicity in normal clinical use.

Older tricyclic antidepressants and their toxicity in overdose and in clinical use Tricyclic antidepressants were first used in the 1950s. Their use for depression has gone down in the past 20 or so years. This is because newer antidepressants are better tolerated and less toxic in overdose. Certain tricyclics - dosulepin and amitriptyline - have been identified as being particularly toxic tricyclics and their use has been restricted. However many other tricyclics remain widely used for depression and many other conditions. We examined all the evidence we could find on tricyclic toxicity. We found that, with one exception, all tricyclics are toxic and dangerous when taken in overdose. The exception is lofepramine - a tricyclic used in the UK and some other countries. When looking at toxicity in clinical use, we found no consistent evidence of difference between individual tricyclics. It is possible that most or all tricyclics do not increase the risk of heart attack or sudden cardiac death when used at normal clinical doses.

Metabolic adaptation in epithelial ovarian cancer metastasis.

Epithelial ovarian cancer (EOC) is highly lethal due to its unique metastatic characteristics. EOC spheroids enter a non-proliferative state, with hypoxic cores and reduced oncogenic signaling, all of which contribute to tumour dormancy during metastasis. We investigated the metabolomic states of EOC cells progressing through the three steps to metastasis. Metabolomes of adherent, spheroid, and re-adherent cells were validated by isotopic metabolic flux analysis and mitochondrial functional assays to identify metabolic pathways that were previously unknown to promote EOC metastasis. Although spheroids were thought to exist in a dormant state, metabolomic analysis revealed an unexpected upregulation of energy production pathways in spheroids, accompanied by increased abundance of tricarboxylic acid (TCA) cycle and electron transport chain proteins. Tracing of 13C-labelled glucose and glutamine showed increased pyruvate carboxylation and decreased glutamine anaplerosis in spheroids. Increased reductive carboxylation suggests spheroids adjust redox homeostasis by shuttling cytosolic NADPH into mitochondria via isocitrate dehydrogenase. Indeed, we observed spheroids have increased respiratory capacity and mitochondrial ATP production. Relative to adherent cells, spheroids reduced serine consumption and metabolism, processes which were reversed upon spheroid re-adherence. The data reveal a distinct metabolism in EOC spheroids that enhances energy production by the mitochondria while maintaining a dormant state with respect to growth and proliferation. The findings advance our understanding of EOC metastasis and identify the TCA cycle and mitochondrional activity as novel targets to disrupt EOC metastasis, providing new approaches to treat advanced disease.

Replenishment of TCA cycle intermediates and long-noncoding RNAs regulation in breast cancer.

The tricarboxylic acid (TCA) cycle is an essential interface that coordinates cellular metabolism and is as a primary route determining the fate of a variety of fuel sources, including glucose, fatty acid and glutamate. The crosstalk of nutrients replenished TCA cycle regulates breast cancer (BC) progression by changing substrate levels-induced epigenetic alterations, especially the methylation, acetylation, succinylation and lactylation. Long non-coding RNAs (lncRNA) have dual roles in inhibiting or promoting energy reprogramming, and so altering the metabolic flux of fuel sources to the TCA cycle, which may regulate epigenetic modifications at the cellular level of BC. This narrative review discussed the central role of the TCA cycle in interconnecting numerous fuels and the induced epigenetic modifications, and the underlying regulatory mechanisms of lncRNAs in BC.

Protection of Gueichih-Fuling-Wan on cerebral ischemia-induced brain injury in rodents is mediated by trans-cinnamaldehyde via inhibition of neuroinflammation and apoptosis.

Background: Stroke is the leading cause of mortality and morbidity worldwide, and an effective therapeutic strategy for the prevention of patients with cerebral ischemia induced brain injury is lacking. Traditional Chinese medicine with neuroprotective activities might be beneficial and provide alternative therapeutic opportunities for cerebral ischemia. Purposes: This study aimed to evaluate the neuroprotection and possible mechanisms of Gueichih-Fuling-Wan (GFW), its' constitutive herbs, and their active compounds on cerebral ischemia/reperfusion (I/R)-induced brain injury in rodents. Methods: Various doses of extracts (0.25, 0.5, and 1.0 g/kg) of GFW and five constituent herbs (Cinnamomi Cortex, CC; Poria cocos, PC; Paeonia lactifloa, PL; Paeonia suffruticosa, PS and Prunus perisica, PP) were orally administered. Different doses of active compounds (0.5, 1.0, and 2.0 mg/kg) of GFW such as cinnamaldehyde, cinnamic acid (from CC), paeoniflorin (from PL), and paeonol (from PS) were intraperitoneally administered. Their effects on cerebral ischemia/ reperfusion (I/R)induced brain injury in rodents were evaluated. Results: GFW, its' constituent herbs, and the active compounds reduced the infarct area dose-dependently (***P < 0.001). Cinnamaldehyde showed the most significant reduction (***P < 0.001). Therefore, trans-cinnamaldehyde (TCA) was further used to evaluate the neuroprotective mechanism of the I/R-induced brain injury. TCA (10, 20, 30 mg/ kg, p.o.) showed an inhibitory effect of I/R-induced brain damage in mice in a dose-dependent manner. Besides, GFW and TCA dose-dependently reduced the COX-2 protein expression level, and TCA reduced the TUNEL (+) apoptosis. TCA dose-dependently increased the pro-survival NR2A and Bcl-2 protein expression level and decreased the pro-apoptotic NR2B and cytochrome c, caspase 9, and caspase 3 expression (***P < 0.001). Conclusion: The above data revealed that GFW, its' constituent herbs, and active compounds protected against I/R-induced brain injury in rodents. TCA from CC might participate in GFW protecting against cerebral ischemia-induced brain injury by inhibiting neuroinflammation and apoptosis.

Hypoxia makes EZH2 inhibitor not easy-advances of crosstalk between HIF and EZH2.

Histone methylation plays a crucial role in tumorigenesis. Enhancer of zeste homolog 2 (EZH2) is a histone methyltransferase that regulates chromatin structure and gene expression. EZH2 inhibitors (EZH2is) have been shown to be effective in treating hematologic malignancies, while their effectiveness in solid tumors remains limited. One of the major challenges in the treatment of solid tumors is their hypoxic tumor microenvironment. Hypoxia-inducible factor 1-alpha (HIF-1α) is a key hypoxia responder that interacts with EZH2 to promote tumor progression. Here we discuss the implications of the relationship between EZH2 and hypoxia for expanding the application of EZH2is in solid tumors.

Reprogrammed mitochondria: a central hub of cancer cell metabolism.

Mitochondria represent the metabolic hub of normal cells and play this role also in cancer but with different functional purposes. While cells in differentiated tissues have the prerogative of maintaining basal metabolism and support the biosynthesis of specialized products, cancer cells have to rewire the metabolic constraints imposed by the differentiation process. They need to balance the bioenergetic supply with the anabolic requirements that entail the intense proliferation rate, including nucleotide and membrane lipid biosynthesis. For this aim, mitochondrial metabolism is reprogrammed following the activation of specific oncogenic pathways or due to specific mutations of mitochondrial proteins. The main process leading to mitochondrial metabolic rewiring is the alteration of the tricarboxylic acid cycle favoring the appropriate orchestration of anaplerotic and cataplerotic reactions. According to the tumor type or the microenvironmental conditions, mitochondria may decouple glucose catabolism from mitochondrial oxidation in favor of glutaminolysis or disable oxidative phosphorylation for avoiding harmful production of free radicals. These and other metabolic settings can be also determined by the neo-production of oncometabolites that are not specific for the tissue of origin or the accumulation of metabolic intermediates able to boost pro-proliferative metabolism also impacting epigenetic/transcriptional programs. The full characterization of tumor-specific mitochondrial signatures may provide the identification of new biomarkers and therapeutic opportunities based on metabolic approaches.

The tricarboxylic acid cycle is inhibited under acute stress from carbonate alkalinity in the gills of Eriocheir sinensis.

Owing to population growth and environmental pollution, freshwater aquaculture has been rapidly shrinking in recent years. Aquaculture in saline-alkaline waters is a crucial strategy to meet the increasing demand for aquatic products. The Chinese mitten crab is an important economic food in China, but the molecular mechanism by which it tolerates carbonate alkalinity (CA) in water remains unclear. Here, we found that enzyme activities of the tricarboxylic acid (TCA) cycle in the gills, such as citrate synthase, isocitrate dehydrogenase, α-ketoglutarate dehydrogenase, and malate dehydrogenase, were markedly reduced under CA stress induced by 40 mM NaHCO3. Secondly, the TCA cycle in the gills is inhibited under acute CA stress, according to proteomic and metabolomic analyses. The expressions of six enzymes, namely aconitate hydratase, isocitrate dehydrogenase, 2-oxoglutarate dehydrogenase, dihydrolipoyl dehydrogenase, succinate-CoA ligase, and malate dehydrogenase, were downregulated, resulting in the accumulation of phosphoenolpyruvic acid, citric acid, cis-aconitate, and α-ketoglutaric acid. Finally, we testified that if the TCA cycle is disturbed by malonate, the survival rate increases in CA water. To our knowledge, this is the first study to show that the TCA cycle in the gills is inhibited under CA stress. Overall, the results provide new insights into the molecular mechanism of tolerance to saline-alkaline water in crabs, which helped us expand the area for freshwater aquaculture and comprehensively understand the physiological characteristics of crab migration.

Mechanisms associated with cuproptosis and implications for ovarian cancer.

Ovarian cancer, a profoundly fatal gynecologic neoplasm, exerts a substantial economic strain on nations globally. The formidable challenge of its frequent relapse necessitates the exploration of novel cytotoxic agents, efficacious antineoplastic medications with minimal adverse effects, and strategies to surmount resistance to primary chemotherapeutic agents. These endeavors aim to supplement extant pharmacological interventions and elucidate molecular mechanisms underlying induced cytotoxicity, distinct from conventional therapeutic modalities. Recent scientific research has unveiled a novel form of cellular demise, known as copper-death, which is contingent upon the intracellular concentration of copper. Diverging from conventional mechanisms of cellular demise, copper-death exhibits a pronounced reliance on mitochondrial respiration, particularly the tricarboxylic acid (TCA) cycle. Tumor cells manifest distinctive metabolic profiles and elevated copper levels in comparison to their normal counterparts. The advent of copper-death presents alluring possibilities for targeted therapeutic interventions within the realm of cancer treatment. Hence, the primary objective of this review is to present an overview of the proteins and intricate mechanisms associated with copper-induced cell death, while providing a comprehensive summary of the knowledge acquired regarding potential therapeutic approaches for ovarian cancer. These findings will serve as valuable references to facilitate the advancement of customized therapeutic interventions for ovarian cancer.

Elevated PINK1/Parkin-Dependent Mitophagy and Boosted Mitochondrial Function Mediate Protection of HepG2 Cells from Excess Palmitic Acid by Hesperetin.

Deregulation of mitochondrial functions in hepatocytes contributes to many liver diseases, such as nonalcoholic fatty liver disease (NAFLD). Lately, it was referred to as MAFLD (metabolism-associated fatty liver disease). Hesperetin (Hst), a bioactive flavonoid constituent of citrus fruit, has been proven to attenuate NAFLD. However, a potential connection between its preventive activities and the modulation of mitochondrial functions remains unclear. Here, our results showed that Hst alleviates palmitic acid (PA)-triggered NLRP3 inflammasome activation and cell death by inhibition of mitochondrial impairment in HepG2 cells. Hst reinstates fatty acid oxidation (FAO) rates measured by seahorse extracellular flux analyzer and intracellular acetyl-CoA levels as well as intracellular tricarboxylic acid cycle metabolites levels including NADH and FADH2 reduced by PA exposure. In addition, Hst protects HepG2 cells against PA-induced abnormal energetic profile, ATP generation reduction, overproduction of mitochondrial reactive oxygen species, and collapsed mitochondrial membrane potential. Furthermore, Hst improves the protein expression involved in PINK1/Parkin-mediated mitophagy. Our results demonstrate that it restores PA-impaired mitochondrial function and sustains cellular homeostasis due to the elevation of PINK1/Parkin-mediated mitophagy and the subsequent disposal of dysfunctional mitochondria. These results provide therapeutic potential for Hst utilization as an effective intervention against fatty liver disease.