BACKGROUND: 2,3,5,4\'-tetrahydroxy-stilbene-2-O-β-D-glucoside (TSG) is the principal bioactive compound contained in Polygonum multiflorum Thunb. (PMT), which is traditionally recorded to possess tonic and anti-aging efficacy.
OBJECTIVE: To identify the TSG-provided promotion on liver regeneration (LR) following partial hepatectomy (PHx) in mice and to explicate its involved mechanism.
METHODS: The promotion of TSG on LR was evaluated by hematoxylin and eosin (H&E), 5-bromodeoxyuridinc (BrdU) and Ki-67 staining, and measuring the level of proliferating cell nuclear antigen (PCNA) and Cyclin D1 in mice with PHx at different time points. Gene Expression Omnibus (GEO, GSE15239) database and the label-free quantitative proteomics from liver of mice at 24 h after PHx were integrated to identify potential involved critical proteins, which were verified by Western-blot, Real-time polymerase chain reaction (RT-PCR), molecular docking and luciferase activity assay. Primary hepatocytes isolated from mice were used to investigate the TSG-provided promotion on proliferation in vitro.
RESULTS: TSG (20 mg/kg) promoted LR in mice after PHx. Results from RNA expression data from clinical samples and proteomic analysis from liver tissues indicated that peroxisome proliferator-activated receptor α (PPARα)-mediated fatty acid metabolism pathway were crucially associated with the TSG-provided promotion on LR. TSG enhanced the nuclear translocation of PPARα and the mRNA expression of a series of PPARα-regulated downstream genes. In addition, TSG lowered hepatic triglyceride (TG) and non-esterified fatty acid (NEFA) amounts and increased hepatic adenosine triphosphate (ATP) level in mice after PHx. TSG up-regulated the transcriptional activity of PPARα in vitro. Next results displayed that TSG promoted cell proliferation as well as ATP level in mice primary hepatocytes, which were abolished when PPARα was suppressed. Meanwhile, the cell viability was also elevated in mice primary hepatocytes treated with ATP.
CONCLUSIONS: Activating PPARα-mediated fatty acid β-oxidation (FAO) pathway led to the production of ATP, which contributed to the TSG-provided promotion on LR after PHx in mice.

UNASSIGNED: Extracellular ATP (eATP) released from damaged cells activates the P2X7 receptor (P2X7R) ion channel on the surface of surrounding cells, resulting in calcium influx, potassium efflux and inflammasome activation. Inherited changes in the P2X7R gene (P2RX7) influence eATP induced responses. Single nucleotide polymorphisms (SNPs) of P2RX7 influence both function and signaling of the receptor, that in addition to ion flux includes pathogen control and immunity.
UNASSIGNED: Subjects (n = 105) were admitted to the ICU at the University Hospital Ulm, Germany between June 2018 and August 2019. Of these, subjects with a diagnosis of sepsis (n = 75), were also diagnosed with septic shock (n = 24), and/or pneumonia (n = 42). Subjects with pneumonia (n = 43) included those without sepsis (n = 1), sepsis without shock (n = 29) and pneumonia with septic shock (n = 13). Out of the 75 sepsis/septic shock patients, 33 patients were not diagnosed with pneumonia. Controls (n = 30) were recruited to the study from trauma patients and surgical patients without sepsis, septic shock, or pneumonia. SNP frequencies were determined for 16 P2RX7 SNPs known to affect P2X7R function, and association studies were performed between frequencies of these SNPs in sepsis, septic shock, and pneumonia compared to controls.
UNASSIGNED: The loss-of-function (LOF) SNP rs17525809 (T253C) was found more frequently in patients with septic shock, and non-septic trauma patients when compared to sepsis. The LOF SNP rs2230911 (C1096G) was found to be more frequent in patients with sepsis and septic shock than in non-septic trauma patients. The frequencies of these SNPs were even higher in sepsis and septic patients with pneumonia. The current study also confirmed a previous study by our group that showed a five SNP combination that included the GOF SNPs rs208294 (C489T) and rs2230912 (Q460R) that was designated #21211 was associated with increased odds of survival in severe sepsis.
UNASSIGNED: The results found an association between expression of LOF P2RX7 SNPs and presentation to the ICU with sepsis, and septic shock compared to control ICU patients. Furthermore, frequencies of LOF SNPs were found to be higher in sepsis patients with pneumonia compared to those without pneumonia. In addition, a five SNP GOF combination was associated with increased odds of survival in severe sepsis. These results suggest that P2RX7 is required to control infection in pneumonia and that inheritance of LOF variants increases the risk of sepsis when associated with pneumonia. This study confirms that P2RX7 genotyping in pneumonia may identify patients at risk of developing sepsis. The study also identifies P2X7R as a target in sepsis associated with an excessive immune response in subjects with GOF SNP combinations.

Mature red blood cells (RBCs) lack mitochondria and thus exclusively rely on glycolysis to generate adenosine triphosphate (ATP) during aging in vivo or storage in blood banks. Here, we leveraged 13,029 volunteers from the Recipient Epidemiology and Donor Evaluation Study to identify associations between end-of-storage levels of glycolytic metabolites and donor age, sex, and ancestry-specific genetic polymorphisms in regions encoding phosphofructokinase 1, platelet (detected in mature RBCs); hexokinase 1 (HK1); and ADP-ribosyl cyclase 1 and 2 (CD38/BST1). Gene-metabolite associations were validated in fresh and stored RBCs from 525 Diversity Outbred mice and via multi-omics characterization of 1,929 samples from 643 human RBC units during storage. ATP and hypoxanthine (HYPX) levels-and the genetic traits linked to them-were associated with hemolysis in vitro and in vivo, both in healthy autologous transfusion recipients and in 5,816 critically ill patients receiving heterologous transfusions, suggesting their potential as markers to improve transfusion outcomes.

Autophagy is a lysosome-mediated self-degradation process of central importance for cellular quality control. It also provides macromolecule building blocks and substrates for energy metabolism during nutrient or energy deficiency, which are the main stimuli for autophagy induction. However, like most biological processes, autophagy itself requires ATP, and there is an energy threshold for its initiation and execution. We here present the first comprehensive review of this often-overlooked aspect of autophagy research. The studies in which ATP deficiency suppressed autophagy in vitro and in vivo were classified according to the energy pathway involved (oxidative phosphorylation or glycolysis). A mechanistic insight was provided by pinpointing the critical ATP-consuming autophagic events, including transcription/translation/interaction of autophagy-related molecules, autophagosome formation/elongation, autophagosome fusion with the lysosome, and lysosome acidification. The significance of energy-dependent fine-tuning of autophagic response for preserving the cell homeostasis, and potential implications for the therapy of cancer, autoimmunity, metabolic disorders, and neurodegeneration are discussed.

OBJECTIVE: A 15-s all-out sprint cycle test (i.e., νLamax-test) and the post-exercise change in capillary blood lactate concentration is an emerging diagnostic tool that is used to quantify the maximal glycolytic rate. The goal of this study was to determine the relation between 15 s-work, change in capillary blood lactate concentration (∆La) and body composition in a νLamax-test.
METHODS: Fifty cyclists performed a 15 s all-out sprint test on a Cyclus2 ergometer twice after a previous familiarization trial. Capillary blood was sampled before and every minute (for 8 min) after the sprint to determine ∆La. Body composition was determined employing InBody720 eight-electrode impedance analysis.
RESULTS: Simple regression models of fat-free mass (FFM) and also the product of FFM and ∆La showed similar ability to predict 15 s-work (R2 = 0.79; 0.82). Multiple regression combining both predictors explains 93% of variance between individuals. No differences between males and females were found regarding 15 s-work relative to the product of fat-free mass and ∆La. Considering pairs of similar FFM, a change 1 mmol/l of ∆La is estimated to be equal to 12 J/kg in 15 s-work (R2 = 0.85).
CONCLUSIONS: Fifteen s-work is both closely related to FFM and also the product of ∆La and lactate-distribution space approximated by FFM. Differences in 15 s-work between males and females disappear when total lactate production is considered. Considering interindividual differences, the mechanical energy equivalent of blood lactate accumulation seems a robust parameter displaying a clear relationship between ∆La and 15 s-work relative to FFM.

Extracellular vesicle (EV) secretion is mediated by purinergic receptor P2X7 (P2RX7), an ATP-gated cation channel highly expressed in microglia. We have previously shown that administration of GSK1482160, a P2RX7 selective inhibitor, suppresses EV secretion from murine microglia and prevents tauopathy development, leading to the recovery of the hippocampal function in PS19 mice, expressing P301S tau mutant. It is yet unknown, however, whether the effect of GSK1482160 on EV secretion from glial cells is specifically regulated through P2RX7. Here we tested GSK1482160 on primary microglia and astrocytes isolated from C57BL/6 (WT) and P2rx7-/- mice and evaluated their EV secretion and phagocytotic activity of aggregated human tau (hTau) under ATP stimulation. GSK1482160 treatment and deletion of P2rx7 significantly reduced secretion of small and large EVs in microglia and astrocytes in both ATP stimulated or unstimulated condition as determined by nanoparticle tracking analysis, CD9 ELISA and immunoblotting of Tsg101 and Flotilin 1 using isolated EVs. GSK1482160 treatment had no effect on EV secretion from P2rx7 -/- microglia while we observed significant reduction in the secretion of small EVs from P2rx7 -/- astrocytes, suggesting its specific targeting of P2RX7 in EV secretion except small EV secretion from astrocytes. Finally, deletion of P2rx7 suppressed IL-1β secretion and phagocytosed misfolded tau from both microglia and astrocytes. Together, these findings show that GSK1482160 suppresses EV secretion from microglia and astrocytes in P2RX7-dependment manner, and P2RX7 critically regulates secretion of IL-1β and misfolded hTau, demonstrating as the viable target of suppressing EV-mediated neuroinflammation and tau propagation.

Adenosine triphosphate (ATP) can be released into the extracellular milieu from various types of cells in response to a wide range of physical or chemical stresses. In the respiratory tract, extracellular ATP is recognized as an important signal molecule and trigger of airway inflammation. Chlorine (Cl2), sulfur dioxide (SO2), and ammonia (NH3) are potent irritant gases and common industrial air pollutants due to their widespread uses as chemical agents. This study was carried out to determine if acute inhalation challenges of these irritant gases, at the concentration and duration simulating the accidental exposures to these chemical gases in industrial operations, triggered the release of ATP in the rat respiratory tract; and if so, whether the level of ATP in bronchoalveolar lavage fluid (BALF) evoked by inhalation challenge of a given irritant gas was elevated by chronic allergic airway inflammation. Our results showed: 1) Inhalation of these irritant gases caused significant increases in the ATP level in BALF, and the magnitude of evoked ATP release was in the order of Cl2 > SO2 > NH3. 2) Chronic airway inflammation induced by ovalbumin-sensitization markedly elevated the ATP level in BALF during baseline (breathing room air) but did not potentiate the release of ATP in the lung triggered by inhalation challenges of these irritant gases. These findings suggested a possible involvement of the ATP release in the lung in the regulation of overall airway responses to acute inhalation of irritant gases and the pathogenesis of chronic allergic airway inflammation.

Oxidative stress (OS) and disrupted antioxidant defense mechanisms play a pivotal role in the etiology of male infertility. The alterations in reactive oxygen species (ROS) production and calcium (Ca2+) homeostasis are the main activators for the mitochondrial permeability transition pore (mPTP) opening. The mPTP opening is one of the main mechanisms involved in mitochondrial dysfunction in spermatozoa. This alteration in mitochondrial function adversely affects energy supply, sperm motility, and fertilizing capacity and contributes to the development of male infertility. In human spermatozoa, the mPTP opening has been associated with ionomycin-induced endogenous oxidative stress and peroxynitrite-induced nitrosative stress; however, the effect of exogenous oxidative stress on mPTP opening in sperm has not been evaluated. The aim of this study was to determine the effect of exogenous oxidative stress induced by hydrogen peroxide (H2O2) on mPTP opening, mitochondrial function, motility, and cell death markers in human spermatozoa. Human spermatozoa were incubated with 3 mmol/L of H2O2 for 60 min, and intracellular Ca2+ concentration, mPTP opening, mitochondrial membrane potential (ΔΨm), ATP levels, mitochondrial reactive oxygen species (mROS) production, phosphatidylserine (PS) externalization, DNA fragmentation, viability, and sperm motility were evaluated. H2O2-induced exogenous oxidative stress caused increased intracellular Ca2+, leading to subsequent mPTP opening and alteration of mitochondrial function, characterized by ΔΨm dissipation, decreased ATP levels, increased mROS production, and the subsequent alteration of sperm motility. Furthermore, H2O2-induced opening of mPTP was associated with the expression of apoptotic cell death markers including PS externalization and DNA fragmentation. These results highlight the role of exogenous oxidative stress in causing mitochondrial dysfunction, deterioration of sperm motility, and an increase in apoptotic cell death markers, including PS externalization and DNA fragmentation, through the mPTP opening. This study yielded new knowledge regarding the effects of this type of stress on mitochondrial function and specifically on mPTP opening, factors that can contribute to the development of male infertility, considering that the role of mPTP in mitochondrial dysfunction in human sperm is not completely elucidated. Therefore, these findings are relevant to understanding male infertility and may provide an in vitro model for further research aimed at improving human sperm quality.

Here, we demonstrate that human neutrophil interaction with the bacterium Salmonella typhimurium fuels leukotriene B4 synthesis induced by the chemoattractant fMLP. In this work, we found that extracellular ATP (eATP), the amount of which increases sharply during tissue damage, can effectively regulate fMLP-induced leukotriene B4 synthesis. The vector of influence strongly depends on the particular stage of sequential stimulation of neutrophils by bacteria and on the stage at which fMLP purinergic signaling occurs. Activation of 5-lipoxygenase (5-LOX), key enzyme of leukotriene biosynthesis, depends on an increase in the cytosolic concentration of Ca2+. We demonstrate that eATP treatment prior to fMLP, by markedly reducing the amplitude of the fMLP-induced Ca2+ transient jump, inhibits leukotriene synthesis. At the same time, when added with or shortly after fMLP, eATP effectively potentiates arachidonic acid metabolism, including by Ca2+ fluxes stimulation. Flufenamic acid, glibenclamide, and calmodulin antagonist R24571, all of which block calcium signaling in different ways, all suppressed 5-LOX product synthesis in our experimental model, indicating the dominance of calcium-mediated mechanisms in eATP regulatory potential. Investigation into the adhesive properties of neutrophils revealed the formation of cell clusters when adding fMLP to neutrophils exposed to the bacterium Salmonella typhimurium. eATP added simultaneously with fMLP supported neutrophil polarization and clustering. A cell-derived chemoattractant such as leukotriene B4 plays a crucial role in the recruitment of additional neutrophils to the foci of tissue damage or pathogen invasion, and eATP, through the dynamics of changes in [Ca2+]i, plays an important decisive role in fMLP-induced leukotrienes synthesis during neutrophil interactions with the bacterium Salmonella typhimurium.

Pathological cardiac hypertrophy, a major contributor to heart failure, is closely linked to mitochondrial function. The roles of long noncoding RNAs (lncRNAs), which regulate mitochondrial function, remain largely unexplored in this context. Herein, a previously unknown lncRNA, Gm20257, was identified. It markedly increased under hypertrophic stress in vivo and in vitro. The suppression of Gm20257 by using small interfering RNAs significantly induced cardiomyocyte hypertrophy. Conversely, the overexpression of Gm20257 through plasmid transfection or adeno-associated viral vector-9 mitigated angiotensin II-induced hypertrophic phenotypes in neonatal mouse ventricular cells or alleviated cardiac hypertrophy in a mouse TAC model respectively, thus restoring cardiac function. Importantly, Gm20257 restored mitochondrial complex IV level and enhanced mitochondrial function. Bioinformatics prediction showed that Gm20257 had a high binding score with peroxisome proliferator-activated receptor coactivator-1 (PGC-1α), which could increase mitochondrial complex IV. Subsequently, Western blot analysis results revealed that Gm20257 substantially affected the expression of PGC-1α. Further analyses through RNA immunoprecipitation and immunoblotting following RNA pull-down indicated that PGC-1α was a direct downstream target of Gm20257. This interaction was demonstrated to rescue the reduction of mitochondrial complex IV induced by hypertrophic stress and promote the generation of mitochondrial ATP. These findings suggest that Gm20257 improves mitochondrial function through the PGC-1α-mitochondrial complex IV axis, offering a novel approach for attenuating pathological cardiac hypertrophy.