Enhancement Of Glycolysis Research Articles

Enhanced glucose metabolism through activation of HIF-1\u03b1 covers the energy demand in a rat embryonic heart primordium after heartbeat initiation

The initiation of heartbeat is an essential step in cardiogenesis in the heart primordium, but it remains unclear how intracellular metabolism responds to increased energy demands after heartbeat initiation. In this study, embryos in Wistar rats at embryonic day 10, at which heartbeat begins in rats, were divided into two groups by the heart primordium before and after heartbeat initiation and their metabolic characteristics were assessed. Metabolome analysis revealed that increased levels of ATP, a main product of glucose catabolism, and reduced glutathione, a by-product of the pentose phosphate pathway, were the major determinants in the heart primordium after heartbeat initiation. Glycolytic capacity and ATP synthesis-linked mitochondrial respiration were significantly increased, but subunits in complexes of mitochondrial oxidative phosphorylation were not upregulated in the heart primordium after heartbeat initiation. Hypoxia-inducible factor (HIF)-1α was activated and a glucose transporter and rate-limiting enzymes of the glycolytic and pentose phosphate pathways, which are HIF-1α-downstream targets, were upregulated in the heart primordium after heartbeat initiation. These results suggest that the HIF-1α-mediated enhancement of glycolysis with activation of the pentose phosphate pathway, potentially leading to antioxidant defense and nucleotide biosynthesis, covers the increased energy demand in the beating and developing heart primordium.

Adapted suspension tumor cells rewire metabolic pathways for anchorage-independent survival through AKT activation

Metastatic spread of cancer cells is the main cause of cancer-related death. As cancer cells adapt themselves in a suspended state in the blood stream before penetration and regrowth at distal tissues, understanding their survival strategy in an anchorage-independent condition is important to develop appropriate therapeutics. We have previously generated adapted suspension cells (ASCs) from parental adherent cancer cells to study the characteristics of circulating tumor cells. In this study, we explored metabolic rewiring in MDA-MB-468 ASCs to adapt to suspension growth conditions through extracellular flux analyses and various metabolic assays. We also determined the relationship between AKT activation and metabolic rewiring in ASCs using the AKT inhibitor, MK2206. ASCs reprogramed metabolism to enhance glycolysis and basal oxygen consumption rate. RNA-sequencing analysis revealed the upregulation in the genes related to glycolysis, tricarboxylic acid cycle, and oxidative phosphorylation. The changes in the metabolic program led to a remarkable dependency of ASCs on carbohydrates as an energy source for proliferation as compared to parental adherent cells (ADs). AKT activation was observed in ASCs and those generated from pancreatic and other breast cancer cells, and AKT activation inhibition in ASCs decreased glycolysis and oxygen consumption. AKT activation is an important strategy for obtaining energy through the enhancement of glycolysis in ASCs. The regulation of AKT activity and/or glycolysis may provide a strong therapeutic strategy to prevent the metastatic spread of cancer cells.

Long Non-Coding RNA LINC01572 Promotes Hepatocellular Carcinoma Progression via Sponging miR-195-5p to Enhance PFKFB4-Mediated Glycolysis and PI3K/AKT Activation.

Background: Accumulating evidence indicates that type 2 diabetes mellitus (T2DM) is a risk factor for hepatocellular carcinoma (HCC), and T2DM-associated HCC represents a common type of HCC cases. We herein identify an lncRNA LINC01572 that was aberrantly upregulated in T2DM-related HCC via high-throughput screening. Based on this, the study was undertaken to identify the functional role and mechanism of LINC01572 in HCC progression. Methods: RT-qPCR was used to detect the expressions of LINC01572 in HCC tissues and cell lines. Gain- or loss-of-function assays were applied to evaluate the in vitro and in vivo functional significance of LINC01572 in the HCC cell proliferation, migration, and invasion using corresponding experiments. Bioinformatics, RIP, RNA pull-down, and luciferase reporter assays were performed to explore the regulatory relationship of the LINC01572/miR-195-5p/PFKFB4 signaling axis. Result: In this study, we profiled lncRNAs in HCC tissues and corresponding adjacent tissues from HCC patients with T2DM by RNA sequencing. Our data showed that LINC01572 was aberrantly upregulated in HCC tissues as compared with control, especially in those with concurrent T2DM. The high level of LINC01572 was correlated with advanced tumor stage, increased blood HbA1c level, and shortened survival time. The overexpression of LINC01572 significantly promoted HCC cell proliferation, migration, invasion, and epithelial-to-mesenchymal transition (EMT), while the knockdown of LINC01572 had the opposite effects on HCC cells. A mechanistic study revealed that LINC01572-regulated HCC progression via sponging miR-195-5p to increase the level of PFKFB4 and subsequent enhancement of glycolysis and activation of PI3K-AKT signaling. Conclusion: LINC01572 acts as ceRNA of miR-195-5p to restrict its inhibition of PFKFB4, thereby enhancing glycolysis and activates PI3K/AKT signaling to trigger HCC malignancy.

Exploring the Biological Effect of Biosynthesized Au-Pd Core-Shell Nanoparticles through an Untargeted Metabolomics Approach.

The biosynthesis of Au-Pd core-shell nanoparticles (NPs) with wild-type Escherichia coli (Au-Pd/E. coli) is an excellent newly established, environmentally friendly synthetic method for the fabrication of nanomaterials compared to traditional chemosynthesis. However, there is insufficient detailed bioinformation on the compatibility, metabolic process, and mechanism of this approach. Metabolomics approaches have provided an excellent alternative to numerous bioinformatics approaches for shedding light on the biological response of an organism exposed to external stimuli at the molecular level. In this study, two different doses (8 and 80 μg/mL) of Au-Pd/E. coli were applied to treat human umbilical vein endothelial cells (HUVECs). Gas chromatography/mass spectrometry coupled with bioinformatics was used to analyze the changes in the HUVEC metabolome after treatment. The results indicated the occurrence of nonsignificant acute cytotoxicity based on cell proliferation and apoptosis analysis, while high concentrations (80 μg/mL) of Au-Pd/E. coli induced dramatic changes in energy metabolism, revealing a notable inhibition of the tricarboxylic acid (TCA) cycle along with the enhancement of glycolysis, the pentose phosphate pathway, fatty acid biosynthesis, and lipid accumulation, which was correlated with mitochondrial dysfunction. The metabolomics results obtained for this novel Au-Pd/E. coli-cell system could broaden our knowledge of the biological effect of Au-Pd/E. coli and possibly reveal material modifications and technological innovations.

Why may citrate sodium significantly increase the effectiveness of transarterial chemoembolization in hepatocellular carcinoma?

Hepatocellular carcinoma (HCC) represents the third cause of cancer death in men worldwide, and its increasing incidence can be explained by the increasing occurrence of non-alcoholic steatohepatitis (NASH). HCC prognosis is poor, as its 5-year overall survival is approximately 18 % and most cases are diagnosed at an inoperable advanced stage. Moreover, tumor sensitivity to conventional chemotherapeutics (particularly to cisplatin-based regimen), trans-arterial chemoembolization (cTACE), tyrosine kinase inhibitors, anti-angiogenic molecules and immune checkpoint inhibitors is limited. Oncogenic signaling pathways, such as HIF-1α and RAS/PI3K/AKT, may provoke drug resistance by enhancing the aerobic glycolysis ("Warburg effect") in cancer cells. Indeed, this metabolism, which promotes cancer cell development and aggressiveness, also induces extracellular acidity. In turn, this acidity promotes the protonation of drugs, hence abrogating their internalization, since they are most often weakly basic molecules. Consequently, targeting the Warburg effect in these cancer cells (which in turn would reduce the extracellular acidification) could be an effective strategy to increase the delivery of drugs into the tumor. Phosphofructokinase-1 (PFK1) and its activator PFK2 are the main regulators of glycolysis, and they also couple the enhancement of glycolysis to the activation of key signaling cascades and cell cycle progression. Therefore, targeting this "Gordian Knot" in HCC cells would be of crucial importance. Here, we suggest that this could be achieved by citrate administration at high concentration, because citrate is a physiologic inhibitor of PFK1 and PFK2. As shown in various in vitro studies, including HCC cell lines, administration of high concentrations of citrate inhibits PFK1 and PFK2 (and consequently glycolysis), decreases ATP production, counteracts HIF-1α and PI3K/AKT signaling, induces apoptosis, and sensitizes cells to cisplatin treatment. Administration of high concentrations of citrate in animal models (including Ras-driven tumours) has been shown to effectively inhibit cancer growth, reverse cell dedifferentiation, and neutralize intratumor acidity, without apparent toxicity in animal studies. Citrate may also induce a rapid secretion of pro-inflammatory cytokines by macrophages, and it could favour the destruction of cancer stem cells (CSCs) sustaining tumor recurrence. Consequently, this "citrate strategy" could improve the tumor sensitivity to current treatments of HCC by reducing the extracellular acidity, thus enhancing the delivery of chemotherapeutic drugs into the tumor. Therefore, we propose that this strategy should be explored in clinical trials, in particular to enhance cTACE effectiveness.

Abstract 9817: Krüppel-Like Factor 4 Integrates Immunometabolism of Human Arterial Endothelial Cells

Introduction: Inflammation and metabolic alterations are two common hallmarks of cardiovascular diseases. Yet, the molecular mechanisms integrating inflammation and cell metabolism remain elusive. Objective: We investigated whether Krüppel-like factor 4 (KLF4) serves as a link between cellular glucose metabolism and inflammation in human arterial endothelial cells. Methods and Results: Primary human pulmonary artery and aortic endothelial cells (PAEC and AoEC, respectively) were stimulated with tumor necrosis factor α (TNFα) or lipopolysaccharide (LPS). Results from fluorescent microscopy and Seahorse extracellular flux analysis revealed that TNFα and LPS enhanced glucose uptake by 2.2-fold, glycolysis by 2.3-fold, and mitochondrial respiration by 1.6-fold in PAEC and AoEC. The increase in glycolysis correlated with a 2-4-fold upregulation of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) and PFKFB4, two key regulatory enzymes of glycolysis. Silencing PFKFB3 but not PFKFB4 entirely prevented TNFα-induced enhancement of glycolysis with a concomitant metabolic shift to mitochondrial respiration. Mechanistically, TNFα and LPS stimulated KLF4 mRNA and protein expression (2-4-fold), which functions as a transcriptional repressor of PFKFB3 . KLF4 knockdown potentiated TNFα-induced stimulation of PFKFB3 expression by 1.6-fold and glycolysis by 2.2-fold, effects which were completely prevented by co-silencing of PFKFB3 . Functionally, KLF4 silencing exacerbated TNFα-induced vascular cell adhesion molecule 1 (VCAM1) expression (by 2-3-fold), E-selectin secretion (by 2.8-fold), and monocyte adhesion (by 1.6-fold) in PAEC, all of which were attenuated by over 50% when PFKFB3 was inhibited by siRNA or with 3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3-PO). By contrast, KLF4 overexpression-mediated inhibition of inflammation was significantly counteracted in PAEC with co-overexpression of PFKFB3 . Conclusion: These results indicate that KLF4 inhibits inflammation by normalizing PFKFB3-mediated enhancement of glycolysis and that the KLF4-PFKFB3 signaling axis integrates immunometabolism in human arterial endothelial cells.

Hirsutine ameliorates hepatic and cardiac insulin resistance in high-fat diet-induced diabetic mice and in vitro models

Closely associated with type 2 diabetes mellitus (T2DM), hepatic steatosis and cardiac hypertrophy resulting from chronic excess intake can exacerbate insulin resistance (IR). The current study aims to investigate the pharmacological effects of hirsutine, one indole alkaloid isolated from Uncaria rhynchophylla, on improving hepatic and cardiac IR, and elucidate the underlying mechanism. T2DM and IR in vivo were established by high-fat diet (HFD) feeding for 3 months in C57BL/6 J mice. In vitro IR models were induced by high-glucose and high-insulin (HGHI) incubation in HepG2 and H9c2 cells. Hirsutine administration for 8 weeks improved HFD-induced peripheral hyperglycemia, glucose tolerance and IR by OGTT and ITT assays, and simultaneously attenuated hepatic steatosis and cardiac hypertrophy by pathological observation. The impaired p-Akt expression was activated by hirsutine in liver and heart tissues of HFD mice, and also in the models in vitro. Hirsutine exhibited the effects on enhancing glucose consumption and uptake in IR cell models via activating phosphatidylinositol 3-kinase (PI3K)/Akt pathway, which was blocked by PI3K inhibitor LY294002. Moreover, the effect of hirsutine on promoting glucose uptake and GLUT4 expression in HGHI H9c2 cells was also prevented by Compound C, an inhibitor of AMP-activated protein kinase (AMPK). Enhancement of glycolysis might be another factor of hirsutine showing its effects on glycemic control. Collectively, it was uncovered that hirsutine might exert beneficial effects on regulating glucose homeostasis, thus improving hepatic and cardiac IR, and could be a promising compound for treating diet-induced T2DM.

Loss of mTORC2-induced metabolic reprogramming in monocytes uncouples migration and maturation from production of proinflammatory mediators.

Monocyte migration to the sites of inflammation and maturation into macrophages are key steps for their immune effector function. Here, we show that mechanistic target of rapamycin complex 2 (mTORC2)-dependent Akt activation is instrumental for metabolic reprogramming at the early stages of macrophage-mediated immunity. Despite an increased production of proinflammatory mediators, monocytes lacking expression of the mTORC2 component Rictor fail to efficiently migrate to inflammatory sites and fully mature into macrophages, resulting in reduced inflammatory responses in vivo. The mTORC2-dependent phosphorylation of Akt is instrumental for the enhancement of glycolysis and mitochondrial respiration, required to sustain monocyte maturation and motility. These observations are discussed in the context of therapeutic strategies aimed at selective inhibition of mTORC2 activity.

Glycolytic Reprogramming in Silica-Induced Lung Macrophages and Silicosis Reversed by Ac-SDKP Treatment.

Glycolytic reprogramming is an important metabolic feature in the development of pulmonary fibrosis. However, the specific mechanism of glycolysis in silicosis is still not clear. In this study, silicotic models and silica-induced macrophage were used to elucidate the mechanism of glycolysis induced by silica. Expression levels of the key enzymes in glycolysis and macrophage activation indicators were analyzed by Western blot, qRT-PCR, IHC, and IF analyses, and by using a lactate assay kit. We found that silica promotes the expression of the key glycolysis enzymes HK2, PKM2, LDHA, and macrophage activation factors iNOS, TNF-α, Arg-1, IL-10, and MCP1 in silicotic rats and silica-induced NR8383 macrophages. The enhancement of glycolysis and macrophage activation induced by silica was reduced by Ac-SDKP or siRNA-Ldha treatment. This study suggests that Ac-SDKP treatment can inhibit glycolytic reprogramming in silica-induced lung macrophages and silicosis.

Quantitative Proteomics Reveal That Metabolic Improvement Contributes to the Cardioprotective Effect of T89 on Isoproterenol-Induced Cardiac Injury.

BackgroundT89, a traditional Chinese medicine, has passed phase II, and is undergoing phase III clinical trials for treatment of ischemic cardiovascular disease by the US FDA. However, the role of T89 on isoproterenol (ISO)-induced cardiac injury is unknown. The present study aimed to explore the effect and underlying mechanism of T89 on ISO-induced cardiac injury.MethodsMale Sprague-Dawley rats received subcutaneous injection of ISO saline solution at 24 h intervals for the first 3 days and then at 48 h intervals for the next 12 days. T89 at dose of 111.6 and 167.4 mg/kg was administrated by gavage for 15 consecutive days. Rat survival rate, cardiac function evaluation, morphological observation, quantitative proteomics, and Western blotting analysis were performed.ResultsT89 obviously improved ISO-induced low survival rate, attenuated ISO-evoked cardiac injury, as evidenced by myocardial blood flow, heart function, and morphology. Quantitative proteomics revealed that the cardioprotective effect of T89 relied on the regulation of metabolic pathways, including glycolipid metabolism and energy metabolism. T89 inhibited the enhancement of glycolysis, promoted fatty acid oxidation, and restored mitochondrial oxidative phosphorylation by regulating Eno1, Mcee, Bdh1, Ces1c, Apoc2, Decr1, Acaa2, Cbr4, ND2, Cox 6a, Cox17, ATP5g, and ATP5j, thus alleviated oxidative stress and energy metabolism disorder and ameliorated cardiac injury after ISO. The present study also verified that T89 significantly restrained ISO-induced increase of HSP70/HSP40 and suppressed the phosphorylation of ERK, further restored the expression of CX43, confirming the protective role of T89 in cardiac hypertrophy. Proteomics data are available via ProteomeXchange with identifier PXD024641.ConclusionT89 reduced mortality and improves outcome in the model of ISO-induced cardiac injury and the cardioprotective role of T89 is correlated with the regulation of glycolipid metabolism, recovery of mitochondrial function, and improvement of myocardial energy.

Investigating the effect of Ti3C2 (MXene) nanosheet on human umbilical vein endothelial cells via a combined untargeted and targeted metabolomics approach

Ti3C2 is the first member of two-dimensional (2D) transition metal carbide or carbonitride (MXene) with excellent photothermal effect in disease treatment on an animal model, which shows a potential prospect on clinical application. However, in-depth details on the biosafety of MXene were insufficient. Metabolomics approach has offered an excellent alternative with numerous bioinformation, which can demonstrate the response of an organism to external stimuli at the molecular level. In this study, two different concentrations (100 and 500 mg/L) of MXene were used to treat human umbilical vein endothelial cells (HUVECs), and under both conditions, no obvious acute cytotoxicity was observed by cell proliferation and apoptosis measurement. We used a platform combining LC-MS/MS, GC-MS, and bioinformatics to analyze the changes of HUVECs metabolome after treatment with different concentrations of MXene, and the results indicated that —high concentrations (500 mg/L) of MXene can cause significant changes in the energy metabolism of HUVECs, showing obvious inhibition of tricarboxylic acid (TCA) cycle with the enhancement of glycolysis, fatty acid biosynthesis, and lipid accumulation, which are closely related to the functional disorder of mitochondria. The metabolomics results of the novel MXene-cell system extend the knowledge on the biological effect of MXene, possibly enabling technological innovations and material modifications.

Metabolic Reprogramming Induces Immune Cell Dysfunction in the Tumor Microenvironment of Multiple Myeloma.

Tumor cells rewire metabolism to meet their increased nutritional demands, allowing the maintenance of tumor survival, proliferation, and expansion. Enhancement of glycolysis and glutaminolysis is identified in most, if not all cancers, including multiple myeloma (MM), which interacts with a hypoxic, acidic, and nutritionally deficient tumor microenvironment (TME). In this review, we discuss the metabolic changes including generation, depletion or accumulation of metabolites and signaling pathways, as well as their relationship with the TME in MM cells. Moreover, we describe the crosstalk among metabolism, TME, and changing function of immune cells during cancer progression. The overlapping metabolic phenotype between MM and immune cells is discussed. In this sense, targeting metabolism of MM cells is a promising therapeutic approach. We propose that it is important to define the metabolic signatures that may regulate the function of immune cells in TME in order to improve the response to immunotherapy.

Effect of per os administration of dihydroquercetin aqueous form on energy exchange in blood lymphocytes of rats with experimental cardiomyopathy

Cardiomyopathies are among the most severe myocardial pathologies, which are characterized by resistance to therapy and high mortality due to increasing heart failure and arrhythmia. Cardiomyocyte pathological changes upon cardiomyopathies are associated with mitochondrial dysfunction, leading to excessive formation of reactive oxygen species and the development of oxidative stress. In this regard, the study of the therapeutic potential of antioxidants in cardiomyopathies, as well as the mechanisms of their action on the functioning of mitochondria, is relevant and of high practical importance. The aim of this study was to determine the effect of oral 14-day administration of dihydroquercetin in a water-soluble form (DHQWF) on the activity of the key marker of mitochondrial respiration [succinate dehydrogenase (SDH)] and the cytoplasmic marker of glycolysis [lactate dehydrogenase (LDH)] in blood lymphocytes, as well as on the serum level of lipid peroxidation (LPO) in control rats and rats with experimental cardiomyopathy. Material and methods. Adult male Wistar rats (body weight 220-240 g) were used for the study. Isoprenaline hydrochloride was used to induce cardiomyopathy (IIC) in animals (twice subcutaneous injection at a dose of 150 mg/kg body weight, with a break of 24 hours). DHQ-WF was added to the drinking water for 14 days at the dose of 15 or 30 mg/kg body weight. SDH and LDH activity in lymphocytes was measured using a highly sensitive cytobiochemical method on a blood smear according to the reduction of nitrotetrazolium blue chloride to diformazan of dark blue color. The content of malone dialdehyde (MDA) in the blood serum, heart and liver mitochondria was determined spectrophotometrically using thiobarbituric acid. Mitochondria were isolated from rat tissues by the conventional method of differential centrifugation. Mitochondrial respiration was recorded using a polarographic method. Results. Experimental cardiomyopathy in rats was accompanied by a twofold increase in blood serum MDA level, as well as by a significant increase in SDH and LDH activity in blood lymphocytes. The oral administration of DHQ-WF in cardiomyopathy at a dose of 15 mg/kg body weight led to a significant decrease in serum MDA level, but did not reduce the activity of SDH and LDH in blood lymphocytes, compared with animals with cardiomyopathy that did not receive DHQ-WF. In the control group of animals, the use of DHQ-WF at a dose of 15 mg/kg body weight significantly increased blood lymphocyte LDH activity, but did not have a statistically significant effect on SDH activity and the parameters of mitochondrial respiration and oxidative phosphorylation, the level of MDA in heart and liver mitochondria. Increasing the dose of DHQ-WF administered to 30 mg/kg had less effect on changes in these parameters in control animals. Conclusion. The data obtained indicate that in experimental cardiomyopathy in rats, the course application of DHQ-WF at a dose of 15 mg/kg of body weight acts as an effective antioxidant that prevents the development of lipid peroxidation in blood serum, and can modulate energy metabolism towards the enhancement of glycolysis in blood lymphocytes in control animals.

The value of a metabolic reprogramming-related gene signature for pancreatic adenocarcinoma prognosis prediction.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most fatal malignancies worldwide. Extensive enhancement of glycolysis and reprogramming of lipid metabolism are both associated with the development and progression of PDAC. Previous studies have suggested that various gene signatures could convey prognostic information about PDAC. However, the use of these signatures has some limitations, perhaps because of a lack of knowledge regarding the genetic and energy supply backgrounds of PDAC. Therefore, we conducted multi-mRNA analysis based on metabolic reprogramming to identify novel signatures for accurate prognosis prediction in PDAC patients. In this study, a three-gene signature comprising MET, ENO3 and CD36 was established to predict the overall survival of PDAC patients. The three-gene signature could divide patients into high- and low-risk groups by disparities in overall survival verified by log-rank test in two independent validation cohorts and could differentiate tumors from normal tissues with excellent accuracy in four Gene Expression Omnibus (GEO) cohorts. We also found a positive correlation between the risk score of the gene signature and inherited germline mutations in PDAC predisposition genes. A glycolysis and lipid metabolism-based gene nomogram and corresponding calibration curves showed significant performance for survival prediction in the TCGA-PDAC dataset. The high-risk designation was closely connected with oncological signatures and multiple aggressiveness-related pathways, as determined by gene set enrichment analysis (GSEA). In summary, our study developed a three-gene signature and established a prognostic nomogram that objectively predicted overall survival in PDAC. The findings could provide a reference for the prediction of overall survival and could aid in individualized management for PDAC patients.

The Compound Packaged in Virions is the Key to Trigger Host Glycolysis Machinery for Virus Life Cycle in Cytoplasm

WSSV can package some compounds during the infection, among which palmitic amide significantly promoted virus infection. Palmitic amide packaged in virions was released to upregulate HIF-1, leading to the enhancement of glycolysis. Palmitic amide directly bound to triosephosphate isomerase (TPI), an important enzyme in the glycolysis pathway, enhanced the activity of TPI. The enhanced TPI enzyme activity could upregulate the expression of HIF-1 and promote virus infection.

Metabolic Enhancement of Glycolysis and Mitochondrial Respiration Are Essential for Neuronal Differentiation.

Metabolic reactions provide energy and metabolic substance for cell function. It was recently shown that metabolic reprogramming is a key regulator of cell pluripotency and differentiation. Although many evidences point to a metabolic "switch" toward mitochondrial respiration, the importance of glycolysis and mitochondrial respiration is still controversial. In this study, we differentiated two different neuronal cells and compared the glycolytic and metabolic profile before and after differentiation. The results showed a significant increase in glycolysis (includes basal glycolysis and glycolytic capacity) and mitochondrial respiration (includes mitochondrial basal respiration, adenosine triphosphate production, and mitochondrial respiration capacity) of both SY5Y and neural stem cells (NSCs) during neuronal differentiation, whereas their mitochondrial DNA copies remain unchanged. Antimycin, a mitochondrial inhibitor, reduced cell density of differentiated SY5Y cells. However, for differentiated NSCs, antimycin dedifferentiated the cells, resulted in a significant increase in cell density, and lowered oxidative stress. In conclusion, this study demonstrated that metabolic enhancement of glycolysis and mitochondrial respiration (rather than a "switch") are both important for neuronal differentiation, although only the blocking of mitochondrial respiration reverses the differentiation process.

Targeting SKA3 suppresses the proliferation and chemoresistance of laryngeal squamous cell carcinoma via impairing PLK1\u2013AKT axis-mediated glycolysis

Spindle and kinetochore-associated complex subunit 3 (SKA3) is a well-known regulator of chromosome separation and cell division, which plays an important role in cell proliferation. However, the mechanism of SKA3 regulating tumor proliferation via reprogramming metabolism is unknown. Here, SKA3 is identified as an oncogene in laryngeal squamous cell carcinoma (LSCC), and high levels of SKA3 are closely associated with malignant progression and poor prognosis. In vitro and in vivo experiments demonstrate that SKA3 promotes LSCC cell proliferation and chemoresistance through a novel role of reprogramming glycolytic metabolism. Further studies reveal the downstream mechanisms of SKA3, which can bind and stabilize polo-like kinase 1 (PLK1) protein via suppressing ubiquitin-mediated degradation. The accumulation of PLK1 activates AKT and thus upregulates glycolytic enzymes HK2, PFKFB3, and PDK1, resulting in enhancement of glycolysis. Furthermore, our data reveal that phosphorylation at Thr360 of SKA3 is critical for its binding to PLK1 and the increase in glycolysis. Collectively, the novel oncogenic signal axis “SKA3-PLK1-AKT” plays a critical role in the glycolysis of LSCC. SKA3 may serve as a prognostic biomarker and therapeutic target, providing a potential strategy for proliferation inhibition and chemosensitization in tumors, especially for LSCC patients with PLK1 inhibitor resistance.

Dexmedetomidine inhibits LPS-induced proinflammatory responses via suppressing HIF1α-dependent glycolysis in macrophages.

Dexmedetomidine, a highly selective α2-adrenoceptor agonist, has been reported to exert an anti-inflammatory effect in several animal models, but the mechanism remains unclear. Previous studies have shown that hypoxia inducible factor 1α-induced glycolysis is essential for the activation of inflammatory macrophages. However, whether dexmedetomidine influences hypoxia inducible factor 1α-induced glycolysis and thus exerts an anti-inflammatory effect has been poorly investigated. This study aims to elucidate the anti-inflammatory mechanism of dexmedetomidine involving the hypoxia inducible factor 1α-dependent glycolytic pathway. We showed that dexmedetomidine could suppress lipopolysaccharide-induced inflammatory cytokine production; inhibit the extracellular acidification rate, glucose consumption and lactate production; and decrease the expression of glycolytic genes in macrophages. The enhancement of glycolysis by the granulocyte-macrophage colony-stimulating factor or higher concentration of glucose could reverse the anti-inflammatory effect of dexmedetomidine on lipopolysaccharide-treated macrophages. Moreover, dexmedetomidine significantly inhibited the upregulation of hypoxia inducible factor 1α at the mRNA and protein levels. Genetic inhibition of hypoxia inducible factor 1α expression could reverse the anti-inflammatory effect of dexmedetomidine. Taken together, our results indicate that dexmedetomidine attenuates lipopolysaccharide-induced proinflammatory responses partially by suppressing hypoxia inducible factor 1α-dependent glycolysis in macrophages.

Insulin-like growth factor 1-induced enolase 2 deacetylation by HDAC3 promotes metastasis of pancreatic cancer

Enolase 2 (ENO2) is a key glycolytic enzyme in the metabolic process of glycolysis, but its potential function in pancreatic ductal adenocarcinoma (PDAC) is unclear. In this study, we observed a significant overexpression of ENO2 in PDAC tissues, and its expression was correlated with metastasis and poor prognosis in PDAC patients. K394 was identified as a major acetylation site in ENO2 that regulates its enzymatic activity, cell metabolism and PDAC progression. Knockdown of ENO2 suppressed tumor growth and liver metastasis in PDAC. Re-expression of wild-type (WT) ENO2, but not the K394 acetylation mimetic mutant, could reverse the decreased tumor malignancy. We further characterized histone deacetylase 3 (HDAC3) and P300/CBP-associated factor (PCAF) as the potential deacetylase and acetyltransferase for ENO2, respectively. HDAC3-mediated deacetylation was shown to lead to ENO2 activation and enhancement of glycolysis. Importantly, insulin-like growth factor-1 (IGF-1) was found to decrease K394 acetylation and stimulate ENO2 activity in a dose- and time-dependent manner. The PI3K/AKT/mTOR pathway facilitated the phosphorylation of HDAC3 on S424, which promoted K394 deacetylation and activation of ENO2. Linsitinib, an oral small-molecule inhibitor of IGF-1R, could inhibit IGF-1-induced ENO2 deacetylation by HDAC3 and the PI3K/AKT/mTOR pathway. Furthermore, linsitinib showed a different effect on the growth and metastasis of PDAC depending on the overexpression of WT versus K394-mutant ENO2. Our results reveal a novel mechanism by which acetylation negatively regulates ENO2 activity in the metastasis of PDAC by modulating glycolysis. Blockade of IGF-1-induced ENO2 deacetylation represents a promising strategy to prevent the development of PDAC.

Transcriptomic profiling sheds light on the blue-light and red-light response of oyster mushroom (Pleurotus ostreatus)

Blue light is an important environmental factor that induces mushroom primordium differentiation and fruiting body development. Although blue-light treatment has been applied for the production of oyster mushroom (Pleurotus ostreatus), the blue-light response mechanisms of P. ostreatus still remain unclear. In the present study, we exposed the primordium of P. ostreatus to blue-light, red-light, and dark conditions for 7 days. Subsequently, comparative transcriptomics analysis of the stipe, pileus, and gill under the three light conditions was performed to reveal the gene expression response mechanism of P. ostreatus to blue light and red light. The results showed that blue light enhanced the growth and development of all the three organs of P. ostreatus, especially the pileus. In contrast, red light slightly (non-significantly) inhibited pileus growth. When compared with red-light and dark treatments, blue-light treatment significantly upregulated gene expression involved in glycolysis/gluconeogenesis, the pentose phosphate pathway and the peroxisome in the pileus, but not in the gill or stipe. Most of the glycolysis and pentose phosphate pathway genes were upregulated in the pileus by blue light. When compared with dark treatment, red-light treatment downregulated the expression of many respiration metabolism genes in the pileus. These results revealed that blue light enhanced the activation of glycolysis and the pentose phosphate pathway, whereas red light weakened glycolysis and pentose phosphate pathway activation. The conclusion can be drawn that blue light improved P. ostreatus fruiting body (particularly, the pileus) growth rate via enhancement of glycolysis and the pentose phosphate pathway.