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European Journal of Sport Science Jun 2024It has been assumed that exercise intensity variation throughout a cycling time trial (TT) occurs in alignment of various metabolic changes to prevent premature task... (Randomized Controlled Trial)
Randomized Controlled Trial
It has been assumed that exercise intensity variation throughout a cycling time trial (TT) occurs in alignment of various metabolic changes to prevent premature task failure. However, this assumption is based on target metabolite responses, which limits our understanding of the complex interconnection of metabolic responses during exercise. The current study characterized the metabolomic profile, an untargeted metabolic analysis, after specific phases of a cycling 4-km TT. Eleven male cyclists performed three separated TTs in a crossover counterbalanced design, which were interrupted at the end of the fast-start (FS, 600 ± 205 m), even-pace (EP, 3600 ± 190 m), or end-spurt (ES, 4000 m) phases. Blood samples were taken before any exercise and 5 min after exercise cessation, and the metabolomic profile characterization was performed using Nuclear Magnetic Resonance metabolomics. Power output (PO) was also continually recorded. There were higher PO values during the FS and ES compared to the EP (all p < 0.05), which were accompanied by distinct metabolomic profiles. FS showed high metabolite expression in TCA cycle and its related pathways (e.g., glutamate, citric acid, and valine metabolism); whereas, the EP elicited changes associated with antioxidant effects and oxygen delivery adjustment. Finally, ES was related to pathways involved in NAD turnover and serotonin metabolism. These findings suggest that the specific phases of a cycling TT are accompanied by distinct metabolomic profiles, providing novel insights regarding the relevance of specific metabolic pathways on the process of exercise intensity regulation.
Topics: Humans; Male; Metabolome; Adult; Bicycling; Cross-Over Studies; Citric Acid Cycle; Serotonin; NAD; Young Adult; Glutamic Acid; Metabolomics; Valine; Citric Acid
PubMed: 38874966
DOI: 10.1002/ejsc.12108 -
Scientific Reports Jun 2024Currently, the increasing pollution of the environment by heavy metals is observed, caused both by natural factors and those related to human activity. They pose a...
Currently, the increasing pollution of the environment by heavy metals is observed, caused both by natural factors and those related to human activity. They pose a significant threat to human health and life. It is therefore important to find an effective way of protecting organisms from their adverse effects. One potential product showing a protective effect is green tea. It has been shown that EGCG, which is found in large amounts in green tea, has strong antioxidant properties and can therefore protect cells from the adverse effects of heavy metals. Therefore, the aim of the study was to investigate the effect of EGCG on cells exposed to Cd. In the study, CHO-K1 cells (Chinese hamster ovary cell line) were treated for 24 h with Cd (5 and 10 µM) and EGCG (0.5 and 1 µM) together or separately. Cell viability, ATP content, total ROS activity, mitochondrial membrane potential and apoptosis potential were determined. The results showed that, in tested concentrations, EGCG enhanced the negative effect of Cd. Further analyses are needed to determine the exact mechanism of action of EGCG due to the small number of publications on the subject and the differences in the results obtained in the research.
Topics: Catechin; Animals; CHO Cells; Apoptosis; Cricetulus; Oxidative Stress; Cadmium; Membrane Potential, Mitochondrial; Reactive Oxygen Species; Cell Survival; Antioxidants; Cricetinae; Adenosine Triphosphate
PubMed: 38871787
DOI: 10.1038/s41598-024-64478-7 -
Nature Communications Jun 2024Serpentinization, a geochemical process found on modern and ancient Earth, provides an ultra-reducing environment that can support microbial methanogenesis and...
Serpentinization, a geochemical process found on modern and ancient Earth, provides an ultra-reducing environment that can support microbial methanogenesis and acetogenesis. Several groups of archaea, such as the order Methanocellales, are characterized by their ability to produce methane. Here, we generate metagenomic sequences from serpentinized springs in The Cedars, California, and construct a circularized metagenome-assembled genome of a Methanocellales archaeon, termed Met12, that lacks essential methanogenesis genes. The genome includes genes for an acetyl-CoA pathway, but lacks genes encoding methanogenesis enzymes such as methyl-coenzyme M reductase, heterodisulfide reductases and hydrogenases. In situ transcriptomic analyses reveal high expression of a multi-heme c-type cytochrome, and heterologous expression of this protein in a model bacterium demonstrates that it is capable of accepting electrons. Our results suggest that Met12, within the order Methanocellales, is not a methanogen but a CO-reducing, electron-fueled acetogen without electron bifurcation.
Topics: Methane; Genome, Archaeal; Archaeal Proteins; Oxidoreductases; Metagenome; Phylogeny; Acetyl Coenzyme A; Carbon Dioxide; Metagenomics
PubMed: 38871712
DOI: 10.1038/s41467-024-48185-5 -
PloS One 2024ATP is actively maintained at high concentrations in cancerous tissues, where it promotes a malignant phenotype through P2 receptors. In this study, we first evaluated...
ATP is actively maintained at high concentrations in cancerous tissues, where it promotes a malignant phenotype through P2 receptors. In this study, we first evaluated the effect of extracellular ATP depletion with apyrase in SKOV-3, a cell line derived from metastatic ovarian carcinoma. We observed a decrease in cell migration and an increase in transepithelial electrical resistance and cell markers, suggesting a role in maintaining a mesenchymal phenotype. To identify the P2 receptor that mediated the effects of ATP, we compared the transcript levels of some P2 receptors and found that P2RX7 is three-fold higher in SKOV-3 cells than in a healthy cell line, namely HOSE6-3 (from human ovarian surface epithelium). Through bioinformatic analysis, we identified a higher expression of the P2RX7 transcript in metastatic tissues than in primary tumors; thus, P2X7 seems to be a promising effector for the malignant phenotype. Subsequently, we demonstrated the presence and functionality of the P2X7 receptor in SKOV-3 cells and showed through pharmacological approaches that its activity promotes cell migration and contributes to maintaining a mesenchymal phenotype. P2X7 activation using BzATP increased cell migration and abolished E-cadherin expression. On the other hand, a series of P2X7 receptor antagonists (A438079, BBG and OxATP) decreased cell migration. We used a CRISPR-based knock-out system directed to P2RX7. According to the results of our wound-healing assay, SKOV3-P2X7KO cells lacked receptor-mediated calcium mobilization and decreased migration. Altogether, these data let us propose that P2X7 receptor is a regulator for cancer cell migration and thus a potential drug target.
Topics: Humans; Receptors, Purinergic P2X7; Cell Movement; Ovarian Neoplasms; Female; Adenosine Triphosphate; Cell Line, Tumor; Epithelial-Mesenchymal Transition; Gene Expression Regulation, Neoplastic
PubMed: 38870128
DOI: 10.1371/journal.pone.0304062 -
MicrobiologyOpen Jun 2024The G protein-coupled estrogen receptor, also known as GPER1 or originally GPR30, is found in various tissues, indicating its diverse functions. It is typically present...
The G protein-coupled estrogen receptor, also known as GPER1 or originally GPR30, is found in various tissues, indicating its diverse functions. It is typically present in immune cells, suggesting its role in regulating immune responses to infectious diseases. Our previous studies have shown that G-1, a selective GPER agonist, can limit the pathogenesis mediated by Staphylococcus aureus alpha-hemolysin (Hla). It aids in clearing bacteria in a mouse skin infection model and restricts the surface display of the Hla receptor, ADAM10 (a disintegrin and metalloprotease 10) in HaCaT keratinocytes. In this report, we delve into the modulation of GPER in human immune cells in relation to the NLRP3 inflammasome. We used macrophage-like differentiated THP-1 cells for our study. We found that treating these cells with G-1 reduces ATP release, decreases the activity of the caspase-1 enzyme, and lessens cell death following Hla intoxication. This is likely due to the reduced levels of ADAM10 and NLRP3 proteins, as well as the decreased display of the ADAM10 receptor in the G-1-treated THP-1 cells. Our studies, along with our previous work, suggest the potential therapeutic use of G-1 in reducing Hla susceptibility in humans. This highlights the importance of GPER in immune regulation and its potential as a therapeutic target.
Topics: ADAM10 Protein; NLR Family, Pyrin Domain-Containing 3 Protein; Humans; Receptors, G-Protein-Coupled; Hemolysin Proteins; Inflammasomes; Bacterial Toxins; THP-1 Cells; Receptors, Estrogen; Amyloid Precursor Protein Secretases; Staphylococcus aureus; Membrane Proteins; Caspase 1; Adenosine Triphosphate; Macrophages; Dipeptides; Hydroxamic Acids
PubMed: 38867416
DOI: 10.1002/mbo3.1423 -
Citrate synthase variants improve yield of acetyl-CoA derived 3-hydroxybutyrate in Escherichia coli.Microbial Cell Factories Jun 2024The microbial chiral product (R)-3-hydroxybutyrate (3-HB) is a gateway to several industrial and medical compounds. Acetyl-CoA is the key precursor for 3-HB, and several...
BACKGROUND
The microbial chiral product (R)-3-hydroxybutyrate (3-HB) is a gateway to several industrial and medical compounds. Acetyl-CoA is the key precursor for 3-HB, and several native pathways compete with 3-HB production. The principal competing pathway in wild-type Escherichia coli for acetyl-CoA is mediated by citrate synthase (coded by gltA), which directs over 60% of the acetyl-CoA into the tricarboxylic acid cycle. Eliminating citrate synthase activity (deletion of gltA) prevents growth on glucose as the sole carbon source. In this study, an alternative approach is used to generate an increased yield of 3-HB: citrate synthase activity is reduced but not eliminated by targeted substitutions in the chromosomally expressed enzyme.
RESULTS
Five E. coli GltA variants were examined for 3-HB production via heterologous overexpression of a thiolase (phaA) and NADPH-dependent acetoacetyl-CoA reductase (phaB) from Cupriavidus necator. In shake flask studies, four variants showed nearly 5-fold greater 3-HB yield compared to the wild-type, although pyruvate accumulated. Overexpression of either native thioesterases TesB or YciA eliminated pyruvate formation, but diverted acetyl-CoA towards acetate formation. Overexpression of pantothenate kinase similarly decreased pyruvate formation but did not improve 3-HB yield. Controlled batch studies at the 1.25 L scale demonstrated that the GltA[A267T] variant produced the greatest 3-HB titer of 4.9 g/L with a yield of 0.17 g/g. In a phosphate-starved repeated batch process, E. coli ldhA poxB pta-ackA gltA::gltA generated 15.9 g/L 3-HB (effective concentration of 21.3 g/L with dilution) with yield of 0.16 g/g from glucose as the sole carbon source.
CONCLUSIONS
This study demonstrates that GltA variants offer a means to affect the generation of acetyl-CoA derived products. This approach should benefit a wide range of acetyl-CoA derived biochemical products in E. coli and other microbes. Enhancing substrate affinity of the introduced pathway genes like thiolase towards acetyl-CoA will likely further increase the flux towards 3-HB while reducing pyruvate and acetate accumulation.
Topics: Escherichia coli; Acetyl Coenzyme A; Citrate (si)-Synthase; 3-Hydroxybutyric Acid; Metabolic Engineering; Escherichia coli Proteins; Ketone Oxidoreductases; Alcohol Oxidoreductases
PubMed: 38867236
DOI: 10.1186/s12934-024-02444-8 -
Nature Communications Jun 2024Radio-immunotherapy exploits the immunostimulatory features of ionizing radiation (IR) to enhance antitumor effects and offers emerging opportunities for treating...
Radio-immunotherapy exploits the immunostimulatory features of ionizing radiation (IR) to enhance antitumor effects and offers emerging opportunities for treating invasive tumor indications such as melanoma. However, insufficient dose deposition and immunosuppressive microenvironment (TME) of solid tumors limit its efficacy. Here we report a programmable sequential therapeutic strategy based on multifunctional fusogenic liposomes (Lip@AUR-ACP-aptPD-L1) to overcome the intrinsic radio-immunotherapeutic resistance of solid tumors. Specifically, fusogenic liposomes are loaded with gold-containing Auranofin (AUR) and inserted with multivariate-gated aptamer assemblies (ACP) and PD-L1 aptamers in the lipid membrane, potentiating melanoma-targeted AUR delivery while transferring ACP onto cell surface through selective membrane fusion. AUR amplifies IR-induced immunogenic death of melanoma cells to release antigens and damage-associated molecular patterns such as adenosine triphosphate (ATP) for triggering adaptive antitumor immunity. AUR-sensitized radiotherapy also upregulates matrix metalloproteinase-2 (MMP-2) expression that combined with released ATP to activate ACP through an "and" logic operation-like process (AND-gate), thus triggering the in-situ release of engineered cytosine-phosphate-guanine aptamer-based immunoadjuvants (eCpG) for stimulating dendritic cell-mediated T cell priming. Furthermore, AUR inhibits tumor-intrinsic vascular endothelial growth factor signaling to suppress infiltration of immunosuppressive cells for fostering an anti-tumorigenic TME. This study offers an approach for solid tumor treatment in the clinics.
Topics: Liposomes; Aptamers, Nucleotide; Animals; Mice; Cell Line, Tumor; Immunotherapy; Melanoma; Humans; Tumor Microenvironment; Matrix Metalloproteinase 2; Gold; Mice, Inbred C57BL; Female; B7-H1 Antigen; Adenosine Triphosphate
PubMed: 38866788
DOI: 10.1038/s41467-024-49482-9 -
Scientific Reports Jun 2024Red blood cells (RBCs) exhibit an interesting response to hydrodynamic flow, releasing adenosine triphosphate (ATP). Subsequently, these liberated ATP molecules initiate...
Red blood cells (RBCs) exhibit an interesting response to hydrodynamic flow, releasing adenosine triphosphate (ATP). Subsequently, these liberated ATP molecules initiate a crucial interaction with endothelial cells (ECs), thereby setting off a cascade involving the release of calcium ions (Ca ). Ca exerts control over a plethora of cellular functions, and acts as a mediator for dilation and contraction of blood vessel walls. This study focuses on the relationship between RBC dynamics and Ca dynamics, based on numerical simulations under Poiseuille flow within a linear two-dimensional channel. It is found that the concentration of ATP depends upon a variety of factors, including RBC density, channel width, and the vigor of the flow. The results of our investigation reveals several features. Firstly, the peak amplitude of Ca per EC escalates in direct proportion to the augmentation of RBC concentration. Secondly, increasing the flow strength induces a reduction in the time taken to reach the peak of Ca concentration, under the condition of a constant channel width. Additionally, when flow strength remains constant, an increase in channel width corresponds to an elevation in calcium peak amplitude, coupled with a decrease in peak time. This implies that Ca signals should transition from relatively unconstrained channels to more confined pathways within real vascular networks. This notion gains support from our examination of calcium propagation in a linear channel. In this scenario, the localized Ca release initiates a propagating wave that gradually encompasses the entire channel. Notably, our computed propagation speed agrees with observations.
Topics: Erythrocytes; Adenosine Triphosphate; Calcium; Endothelial Cells; Humans; Calcium Signaling
PubMed: 38866785
DOI: 10.1038/s41598-024-63306-2 -
Proceedings of the National Academy of... Jun 2024The heart beats approximately 100,000 times per day in humans, imposing substantial energetic demands on cardiac muscle. Adenosine triphosphate (ATP) is an essential...
The heart beats approximately 100,000 times per day in humans, imposing substantial energetic demands on cardiac muscle. Adenosine triphosphate (ATP) is an essential energy source for normal function of cardiac muscle during each beat, as it powers ion transport, intracellular Ca handling, and actin-myosin cross-bridge cycling. Despite this, the impact of excitation-contraction coupling on the intracellular ATP concentration ([ATP]) in myocytes is poorly understood. Here, we conducted real-time measurements of [ATP] in ventricular myocytes using a genetically encoded ATP fluorescent reporter. Our data reveal rapid beat-to-beat variations in [ATP]. Notably, diastolic [ATP] was <1 mM, which is eightfold to 10-fold lower than previously estimated. Accordingly, ATP-sensitive K (K) channels were active at physiological [ATP]. Cells exhibited two distinct types of ATP fluctuations during an action potential: net increases (Mode 1) or decreases (Mode 2) in [ATP]. Mode 1 [ATP] increases necessitated Ca entry and release from the sarcoplasmic reticulum (SR) and were associated with increases in mitochondrial Ca. By contrast, decreases in mitochondrial Ca accompanied Mode 2 [ATP] decreases. Down-regulation of the protein mitofusin 2 reduced the magnitude of [ATP] fluctuations, indicating that SR-mitochondrial coupling plays a crucial role in the dynamic control of ATP levels. Activation of β-adrenergic receptors decreased [ATP], underscoring the energetic impact of this signaling pathway. Finally, our work suggests that cross-bridge cycling is the largest consumer of ATP in a ventricular myocyte during an action potential. These findings provide insights into the energetic demands of EC coupling and highlight the dynamic nature of ATP concentrations in cardiac muscle.
Topics: Myocytes, Cardiac; Adenosine Triphosphate; Excitation Contraction Coupling; Animals; Calcium; Heart Ventricles; Action Potentials; Sarcoplasmic Reticulum; Heart Rate; Humans; KATP Channels; Myocardial Contraction; Mice
PubMed: 38865270
DOI: 10.1073/pnas.2318535121 -
Immunity, Inflammation and Disease Jun 2024This study aimed to link intracellular adenosine triphosphate content in CD4 T lymphocytes (CD4 iATP) with sepsis patient mortality, seeking a new predictive biomarker... (Observational Study)
Observational Study
OBJECTIVE
This study aimed to link intracellular adenosine triphosphate content in CD4 T lymphocytes (CD4 iATP) with sepsis patient mortality, seeking a new predictive biomarker for outcomes and enhanced management.
METHODS
61 sepsis patients admitted to the Intensive Care Unit between October 2021 and November 2022 were enrolled. iATP levels were gauged using whole blood CD4 T cells stimulated with mitogen PHA-L. Based on CD4 iATP levels (<132.24 and ≥132.24 ng/mL), patients were categorized into two groups. The primary endpoint was all-cause mortality. To identify factors associated with mortality, both univariate and multivariate Cox proportional hazard analyses were conducted.
RESULTS
Of the patients, 40 had high CD4 iATP levels (≥132.24 ng/mL) and 21 had low levels (<132.24 ng/mL). In a 28-day follow-up, 21 (34.4%) patients perished. Adjusting for confounders like SOFA score, APACHE II score, lactic acid, and albumin, those with low CD4 iATP had three- to fivefold higher mortality risk compared to high CD4 iATP patients (61.9% vs. 20.0%; hazard ratio [95% confidence interval], Model 1: 4.515 [1.276-15.974], p = .019, Model 2: 3.512 [1.197-10.306], p = .022). CD4 iATP correlated positively with white blood cell and neutrophil counts but not with lymphocytes, CD3, and CD4 counts.
CONCLUSIONS
Low CD4 iATP levels were associated with a higher risk of mortality in sepsis patients. Measurement of CD4 iATP may serve as a useful tool for identifying patients at a higher risk of mortality and could potentially provide a basis for clinical treatment. Further research is warranted to fully elucidate the underlying mechanisms of this association.
Topics: Humans; Adenosine Triphosphate; Sepsis; Male; Female; CD4-Positive T-Lymphocytes; Middle Aged; Prospective Studies; Aged; Biomarkers; Prognosis; Intensive Care Units; Adult
PubMed: 38860755
DOI: 10.1002/iid3.1286