Glucose Uptake Levels Research Articles

Genipin relieves diabetic retinopathy by down-regulation of advanced glycation end products via the mitochondrial metabolism related signaling pathway.

Glycation is an important step in aging and oxidative stress, which can lead to endothelial dysfunction and cause severe damage to the eyes or kidneys of diabetics. Inhibition of the formation of advanced glycation end products (AGEs) and their cell toxicity can be a useful therapeutic strategy in the prevention of diabetic retinopathy (DR). Gardenia jasminoides Ellis (GJE) fruit is a selective inhibitor of AGEs. Genipin is an active compound of GJE fruit, which can be employed to treat diabetes. To confirm the effect of genipin, a vital component of GJE fruit, in preventing human retinal microvascular endothelial cells (hRMECs) from AGEs damage in DR, to investigate the effect of genipin in the down-regulation of AGEs expression, and to explore the role of the CHGA/UCP2/glucose transporter 1 (GLUT1) signal pathway in this process. In vitro, cell viability was tested to determine the effects of different doses of glucose and genipin in hRMECs. Cell Counting Kit-8 (CCK-8), colony formation assay, flow cytometry, immunofluorescence, wound healing assay, transwell assay, and tube-forming assay were used to detect the effect of genipin on hRMECs cultured in high glucose conditions. In vivo, streptozotocin (STZ) induced mice were used, and genipin was administered by intraocular injection (IOI). To explore the effect and mechanism of genipin in diabetic-induced retinal dysfunction, reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and 2-[N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino]-2-deoxy-d-glucose (2-NBDG) assays were performed to explore energy metabolism and oxidative stress damage in high glucose-induced hRMECs and STZ mouse retinas. Immunofluorescence and Western blot were used to investigate the expression of inflammatory cytokines [vascular endothelial growth factor (VEGF), SCG3, tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1β, IL-18, and nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing 3 (NLRP3)]. The protein expression of the receptor of AGEs (RAGE) and the mitochondria-related signal molecules CHGA, GLUT1, and UCP2 in high glucose-induced hRMECs and STZ mouse retinas were measured and compared with the genipin-treated group. The results of CCK-8 and colony formation assay showed that genipin promoted cell viability in high glucose (30 mmol/L D-Glucose)-induced hRMECs, especially at a 0.4 μmol/L dose for 7 d. Flow cytometry results showed that high glucose can increase apoptosis rate by 30%, and genipin alleviated cell apoptosis in AGEs-induced hRMECs. A high glucose environment promoted ATP, ROS, MMP, and 2-NBDG levels, while genipin inhibited these phenotypic abnormalities in AGEs-induced hRMECs. Furthermore, genipin remarkably reduced the levels of the pro-inflammatory cytokines TNF-α, IL-1β, IL-18, and NLRP3 and impeded the expression of VEGF and SCG3 in AGEs-damaged hRMECs. These results showed that genipin can reverse high glucose induced damage with regard to cell proliferation and apoptosis in vitro, while reducing energy metabolism, oxidative stress, and inflammatory injury caused by high glucose. In addition, ROS levels and glucose uptake levels were higher in the retina from the untreated eye than in the genipin-treated eye of STZ mice. The expression of inflammatory cytokines and pathway protein in the untreated eye compared with the genipin-treated eye was significantly increased, as measured by Western blot. These results showed that IOI of genipin reduced the expression of CHGA, UCP2, and GLUT1, maintained the retinal structure, and decreased ROS, glucose uptake, and inflammation levels in vivo. In addition, we found that SCG3 expression might have a higher sensitivity in DR than VEGF as a diagnostic marker at the protein level. Our study suggested that genipin ameliorates AGEs-induced hRMECs proliferation, apoptosis, energy metabolism, oxidative stress, and inflammatory injury, partially via the CHGA/UCP2/GLUT1 pathway. Control of advanced glycation by IOI of genipin may represent a strategy to prevent severe retinopathy and vision loss.

A novel berberine derivative targeting adipocyte differentiation to alleviate TNF-α-induced inflammatory effects and insulin resistance in OP9 cells

Inflammation and insulin resistance play important roles in the development and progression of type 2 diabetes mellitus. The enhancement of adipocyte differentiation can improve insulin sensitivity by increasing glucose uptake, improving insulin signaling, and reducing inflammation. However, only a few adipogenic agents have shown clinical success in patients with type 2 diabetes mellitus. The therapeutic potential of berberine in type 2 diabetes mellitus was confirmed in terms of the target gene-disease relationship using a network pharmacology database prior to synthesizing the derivatives. Novel berberine derivatives were synthesized, and compound 3b promoted adipocyte differentiation and improvement of insulin resistance in OP9 cells. Compound 3b significantly increased the expression of key adipogenic markers including peroxisome proliferator-activated receptor γ (PPARγ) and CCAAT/enhancer binding protein β (C/EBPβ) and promoted lipid accumulation without cytotoxicity. Furthermore, tumor necrosis factor α (TNF-α)-induced inhibition of adipocyte differentiation and the elevation of inflammatory responses were reversed by compound 3b. Subsequently glucose uptake level through insulin sensitivity improvement was enhanced by compound 3b. Mechanistically, TNF-α activated mitogen-activated protein kinases (MAPKs): ERK, JNK, and p38, whereas compound 3b attenuated phosphorylation of three MAPKs. Finally, in silico molecular docking suggested the possible binding sites of compound 3b on PPARγ. Collectively, the adipogenic and glucose uptake effects of compound 3b were associated with its anti-inflammatory effects and reduced phosphorylation of MAPKs. These findings suggest that the berberine derivative compound 3b may be a potent antidiabetic agent.

Low-temperature photothermal-induced alkyl radical release facilitates dihydroartemisinin-triggered “valve-off” starvation therapy

The high nutrient and energy demand of tumor cells compared to normal cells to sustain rapid proliferation offer a potentially auspicious avenue for implementing starvation therapy. However, conventional starvation therapy, such as glucose exhaustion and vascular thrombosis, can lead to systemic toxicity and exacerbate tumor hypoxia. Herein, we developed a new “valve-off” starvation tactic, which was accomplished by closing the valve of glucose transporter protein 1 (GLUT1). Specifically, dihydroartemisinin (DHA), 2,20-azobis [2-(2-imidazolin-2-yl) propane] dihydrochloride (AI), and Ink were co-encapsulated in a sodium alginate (ALG) hydrogel. Upon irradiation with the 1064 nm laser, AI rapidly disintegrated into alkyl radicals (R•), which exacerbated the DHA-induced mitochondrial damage through the generation of reactive oxygen species and further reduced the synthesis of adenosine triphosphate (ATP). Simultaneously, the production of R• facilitated DHA-induced starvation therapy by suppressing GLUT1, which in turn reduced glucose uptake. Systematic in vivo and in vitro results suggested that this radical-enhanced “valve-off” strategy for inducing tumor cell starvation was effective in reducing glucose uptake and ATP levels. This integrated strategy induces tumor starvation with efficient tumor suppression, creating a new avenue for controlled, precise, and concerted tumor therapy.

CS-NO suppresses inhibits glycolysis and gastric cancer progression through regulating YAP/TAZ signaling pathway.

Gastric cancer (GC) is a significant contributor to global mortality and is recognized for its elevated prevalence and fatality rates. Nitric Oxide (NO) plays a role in multiple aspects of cancer metastasis and progression. CS-NO is a polysaccharide-based biomaterial with NO-releasing properties that shows promising therapeutic potential. Nonetheless, the action mechanism of CS-NO in GC is still largely unclear. The present study employed various experimental techniques, including CCK-8 assay, colony formation assay, EdU staining, and transwell assays, to evaluate the proliferation, migration, and invasion of GC cells. Additionally, ELISA was utilized to measure glucose uptake, lactate production, and cellular ATP levels in GC cells. In vivo investigations on nude mice were conducted to validate the in vitro results. The present study aimed to examine the potential anti-tumor properties of CS-NO on GC through in vitro and in vivo investigations, while also exploring the underlying mechanisms involved. Our data suggested that CS-NO might prevent GC cell invasion and migration. Decreased expressions of GLUT1, HK2, and LDHA further demonstrated that CS-NO significantly suppressed aerobic glycolysis in GC cells. The administration of CS-NO resulted in a significant reduction of YAP and TAZ levels in GC cells. Our data further show that CS-NO treatment could inhibit GC cancer growth in mice, consistent with the significant decrease in Ki67, GLUT1 and YAP expression levels. These findings could reveal the good effects of CS-NO therapy on inhibiting GC.

High expression of death-associated protein 5 promotes glucose metabolism in gastric cancer cells and correlates with poor survival outcomes

To investigate the prognostic value of death-associated protein 5 (DAP5) in gastric cancer (GC) and its regulatory effect on aerobic glycolysis in GC cells. We analyzed DAP5 expression levels in GC and adjacent tissues and its association with survival outcomes of GC patients using public databases. We collected paired samples of GC and adjacent tissues from 102 patients undergoing radical resection of GC in our hospital from June, 2012 to July, 2017, and analyzed the correlation of DAP5 expression level detected immunohistochemically with the clinicopathological parameters of the patients. Cox regression analysis, Kaplan-Meier analysis, and ROC curves were used to explore the independent risk factors and the predictive value of DAP5 expression for 5-year survival of the patients. In the cell experiments, we observed the changes in aerobic glycolysis in MGC-803 cells following lentivirus-mediated DAP5 knockdown or overexpression by measuring glucose uptake and cellular lactate level and using qRT-PCR and Western blotting. Analysis using the public databases showed that DAP5 was highly expressed in GC and correlated with tumor progression and poor survival outcomes of the patients (P < 0.05). In the clinical samples, DAP5 expression was significantly higher in GC than in the adjacent tissues (3.19±0.60 vs 1.00±0.12; t=36.863, P < 0.01), and a high expression of DAP5 was associated with a reduced 5-year survival rate of the patients (17.6% vs 72.5%; χ2=29.921, P < 0.05). A high DAP5 expression, T3-4, N2-3, and CEA≥5 ng/mL were identified as independent risk factors affecting 5-year survival outcomes of GC (P < 0.05), for which DAP5 expression showed a prediction sensitivity, specificity and accuracy of 73.2%, 80.4% and 79.0%, respectively. In MGC-803 cells, DAP5 knockdown significantly reduced glucose uptake, lactate level and the expressions of GLUT1, HK2 and LDHA, and DAP5 overexpression produced the opposite effects (P < 0.05). A high expression of DAP5 in GC, which enhances cellular aerobic glycolysis to promote cancer progression, is correlated with a poor survival outcome and may serve as a biomarker for evaluating long-term prognosis of GC patients.

Glucose metabolism and function of CD4+ Tregs are regulated by the TLR8/mTOR signal in an environment of SKOV3 cell growth.

To investigate the role of mammalian target of rapamycin (mTOR) signal in Toll-like receptor (TLR) 8-mediated regulation of glucose metabolism and its effect on reversing immunosuppression in CD4+ regulatory T-cells (Tregs) in ovarian cancer (OC). Fluorescence-activated cell sorting was used to detect the expression levels of mTOR+ and 4E-BP1+ cells in CD4+ Tregs. The prognosis and immune infiltration analysis of mTOR mRNA in OC were performed using the TIMER and Kaplan-Meier plotter database. Furthermore, real-time polymerase chain reaction (RT-PCR) and western blot (WB) were used to detect expression levels of glucose metabolism-related genes and proteins in CD4+ Tregs. Glucose uptake and glycolysis levels were detected by colorimetry, while the effects of CD4+ Tregs on the proliferation of CD4+ T-effector cells (Teffs) were evaluated by carboxyfluorescein diacetate succinimidyl ester (CFSE). mTOR expression in CD4+ Tregs was significantly higher in patients with OC compared with controls and in CD4+ Tregs than in CD4+ Teffs in OC. Additionally, the expression level of mTOR mRNA was related to prognosis and immune infiltration levels in patients with OC. Blocking the mTOR signal resulted in downregulation of glucose metabolism in CD4+ Tregs. Simultaneous inhibition of the mTOR signal while activation of the TLR8 signal had a coordinated inhibitory effect on glucose metabolism and the immunosuppressive function of CD4+ Tregs. Furthermore, the mTOR signal played an essential role in TLR8-mediated reversal of immunosuppressive function in CD4+ Tregs. These findings imply that activation of the TLR8 signal inhibits glucose metabolism in CD4+ Tregs by downregulating mTOR signaling, thereby reversing the immunosuppressive function of these cells in an OC cell growth environment.

Antagonizing Effects of Chromium Against Iron-Decreased Glucose Uptake by Regulating ROS-Mediated PI3K/Akt/GLUT4 Signaling Pathway in C2C12.

To investigate the effect of chromium and iron on glucose metabolism via the PI3K/Akt/GLUT4 signaling pathway. Skeletal muscle gene microarray data in T2DM (GSE7014) was selected using Gene Expression Omnibus database. Element-gene interaction datasets of chromium and iron were extracted from comparative toxicogenomics database (CTD). Gene ontology (GO)and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using DAVID online tool. Cell viability, insulin-stimulated glucose uptake, intracellular reactive oxygen species (ROS) level, and protein expression level were measured in C2C12 cells. The bioinformatics research indicated that PI3K/Akt signaling pathway participated in the effects of chromium and iron associated with T2DM. Insulin-stimulated glucose uptake level was significantly higher in chromium picolinate (Cr group) and lower in ammonium iron citrate (FA group) than that for the control group (P < 0.05); chromium picolinate + ammonium iron citrate (Cr + FA group) glucose uptake level was higher than that for the FA group (P < 0.05). Intracellular ROS level was significantly higher in the FAC group than that for the control group (P < 0.05), and that for the Cr + FA group was lower than that for the FA group (P < 0.05). p-PI3K/PI3K, p-Akt/Akt, and GLUT4 levels were significantly lower in the FA group than that for the control group (P < 0.05), and the Cr + FA group had higher levels than the FA group (P < 0.05). Chromium might have a protective effect on iron-induced glucose metabolism abnormalities through the ROS-mediated PI3K/Akt/GLUT4 signaling pathway.

Salvigenin Suppresses Hepatocellular Carcinoma Glycolysis and Chemoresistance Through Inactivating the PI3K/AKT/GSK-3β Pathway

Salvigenin is a Trimethoxylated Flavone enriched in Scutellariae Barbatae Herba and Scutellariae Radix and is demonstrated to have anti-tumor properties in colon cancer. Notwithstanding, the function and mechanism of Salvigenin in hepatocellular carcinoma (HCC) are less well studied. Different doses of Salvigenin were taken to treat HCC cells. Cell viability, colony formation ability, cell migration, invasion, apoptosis, glucose uptake, and lactate production levels were detected. As shown by the data, Salvigenin concentration dependently dampened HCC cell proliferation, migration, and invasion, weakened glycolysis by abating glucose uptake and lactate generation, and suppressed the profiles of glycolytic enzymes. Moreover, Salvigenin strengthened HCC cells’ sensitivity to 5-fluorouracil (5-FU) and attenuated HCC 5-FU-resistant cells’ resistance to 5-FU. Through network pharmacological analysis, we found Salvigenin potentially regulates PI3K/AKT pathway. As shown by the data, Salvigenin repressed the phosphorylated levels of PI3K, AKT, and GSK-3β. The PI3K activator 740Y-P induced PI3K/AKT/GSK-3β pathway activation and promotive effects in HCC cells. However, Salvigenin substantially weakened 740Y-P-mediated effects. In-vivo assay revealed that Salvigenin hampered the growth and promoted apoptosis of HCC cells in nude mice. Collectively, Salvigenin impedes the aerobic glycolysis and 5-FU chemoresistance of HCC cells by dampening the PI3K/AKT/GSK-3β pathway.

Nebivolol Alleviates Vascular Endothelial Insulin Resistance by Inhibiting Endoplasmic Reticulum Stress.

Vascular endothelial insulin resistance (IR) is an important risk factor in the development of vascular complications in diabetes. Prolonged endoplasmic reticulum stress (ERS) contributes to the development and progression of endothelial IR. The current study assessed the effects and mechanism of nebivolol on vascular IR in Goto-Kakizaki (GK) rats and endothelial IR induced by high glucose (33.3 mmol/L) associated with high insulin (10-7 mol/L) in human aortic endothelial cells (HAECs). Rats were divided into Wistar, Wistar + Neb (Wistar rats treated with nebivolol, 10 mg/kg, ig), GK, and GK + Neb (GK rats treated with nebivolol, 10 mg/kg, ig). GK rats showed hyperglycemia, dyslipidemia, impaired glucose homeostasis, metabolic IR, reduced relaxation to insulin, and lower serum nitric oxide (NO) level. Treatment with nebivolol for 4 months ameliorated insulin's vasorelaxation and NO production, and relieved dyslipidemia in GK rats. Additionally, nebivolol increased glucose uptake and NO level in the endothelial IR group in vitro. Nebivolol increased aortic expressions of IRS-1/PI3K/Akt/eNOS relative proteins and GLUT4 and reduced expressions of ERS markers (ATF6, GRP78, and CHOP, p-JNK/JNK). Furthermore, both nebivolol and TUDCA (ERS inhibitor) alleviated the attenuated IRS-1PI3K/Akt/eNOS pathway and enhanced ERS in HAECs IR. Tunicamycin (ERS inducer) not only induced endothelial IR but also blocked nebivolol's alleviation on the IRS-1PI3K/Akt/eNOS pathway and ERS. Nebivolol ameliorated endothelial IR partially by inhibiting ERS and then regulating the IRS-1/PI3K/Akt/eNOS signal.

Circular RNA circHMCU promotes breast tumorigenesis through miR-4458/PGK1 regulatory cascade

BackgroundCircular RNAs (circRNAs) are abnormally expressed in breast cancer (BC). However, the biological function and mechanism of circHMCU still need to be further explored.MethodsThe expression levels of circHMCU, miR-4458 and phosphoglycerate kinase 1 (PGK1) were measured by quantitative real-time polymerase chain reaction (qRT-PCR) or western blot. The glucose uptake, lactate production and ATP level were assayed by related commercial kits. Cell Counting Kit-8 (CCK8), 5’-ethynyl-2’-deoxyuridine (EdU) and flow cytometry assays were used to test cell proliferation and apoptosis, respectively. The migratory and invasive abilities were detected by transwell and wound-healing assays. The relationships among circHMCU, miR-4458 and PGK1 were verified by dual-luciferase reporter assay. The function of circHMCU in tumor growth was evaluated by animal studies.ResultsCircHMCU was upregulated in BC tissues and cell lines, whereas miR-4458 was downregulated. For biological experiments, circHMCU knockdown inhibited cell proliferation, migration, glycolysis, while promoted cell apoptosis. CircHMCU bound miR-4458, and miR-4458 targeted PGK1. MiR-4458 inhibition reversed circHMCM knockdown-mediated effects on BC cell malignant behaviors. MiR-4458 overexpression suppressed cell glycolysis, proliferation, and metastasis and promoted apoptosis in BC cells through PGK1 upregulation. Additionally, circHMCU suppressed tumor growth in vivo.ConclusionCircHMCU acted as an oncogenic factor by regulating the miR-4458/PGK1 axis in BC.

Taraxasterol Inhibits Hepatic Gluconeogenesis and Increases Glycogen Synthesis via the PI3K/Akt Signaling Pathway

Objective: Taraxasterol (TS) is the main active compound of Taraxacum, which plays a significant role in the treatment of diabetes in many classic prescriptions. However, the mechanisms of TS in the treatment of diabetes remain unclear. This study aimed to investigate the underlying mechanism of TS in hepatic gluconeogenesis and glycogen synthesis in HepG2 cells with insulin resistance (IR). Methods: Molecular docking was conducted by using Discovery Studio (DS) to predict the target of TS in the treatment of diabetes. Then we treated HepG2 cells with glucosamine for 18 h. After the cells were treated with TS, the glucose consumption was examined. Oil red O staining was used to detect the lipid accumulation of HepG2 cells, and cellular glucose uptake levels were assessed using fluorescent 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl) amino)-2-deoxy-D-glucose. The expression of the related proteins of the PI3K/Akt signaling pathway in the HepG2 cells was evaluated by western blot assay. Results: The molecular docking analysis revealed a good binding pose between the insulin receptor and TS. Furthermore, TS administration significantly enhanced glucose uptake and consumption, and reduced lipid accumulation in HepG2 cells with IR. The results of pharmacological mechanism study showed that TS up-regulated glycogenesis by PI3K/Akt/GSK3-motivated GS activation, and down-regulated gluconeogenesis by PI3K/Akt/FoxO1 expression of PEPCK and G6Pase in HepG2 cells with IR. Conclusions: Molecular docking and in vitro experimental results indicate that TS suppresses hepatic gluconeogenesis and augments glycogen synthesis by the PI3K/Akt signaling pathway, and it may have similar effects as insulin in regulating blood glucose.

A Combination of Acetate, Propionate, and Butyrate Increases Glucose Uptake in C2C12 Myotubes

Dietary fibers are subjected to saccharolytic fermentation by the gut microbiota, leading to the production of short chain fatty acids (SCFAs). SCFAs act as signaling molecules to different cells in the human body including skeletal muscle cells. The ability of SCFAs to induce multiple signaling pathways, involving nuclear erythroid 2-related factor 2 (Nrf2), may contribute to the redox balance, and thereby may be involved in glucose homeostasis. The aim of this study is to investigate whether SCFAs increase glucose uptake by upregulating the endogenous antioxidant glutathione (GSH) in C2C12 myotubes. C2C12 myotubes were exposed to 1, 5, or 20 mM of single (acetate, propionate, or butyrate) or mixtures of SCFAs for 24 h. Cytotoxicity, glucose uptake, and intracellular GSH levels were measured. 20 mM of mixture but not separate SCFAs induced cytotoxicity. Exposure to a mixture of SCFAs at 5 mM increased glucose uptake in myotubes, while 20 mM of propionate, butyrate, and mixtures decreased glucose uptake. Exposure to single SCFAs increased GSH levels in myotubes; however, SCFAs did not prevent the menadione-induced decrease in glucose uptake in myotubes. The effect of SCFAs on modulating glucose uptake in myotubes is not associated with the effect on endogenous GSH levels.

Secretin modulates appetite via brown adipose tissue-brain axis

PurposeSecretin activates brown adipose tissue (BAT) and induces satiation in both mice and humans. However, the exact brain mechanism of this satiety inducing, secretin-mediated gut-BAT-brain axis is largely unknown.Methods and resultsIn this placebo-controlled, single-blinded neuroimaging study, firstly using [18F]-fluorodeoxyglucose (FDG) PET measures (n = 15), we established that secretin modulated brain glucose consumption through the BAT-brain axis. Predominantly, we found that BAT and caudate glucose uptake levels were negatively correlated (r = -0.54, p = 0.037) during secretin but not placebo condition. Then, using functional magnetic resonance imaging (fMRI; n = 14), we found that secretin improved inhibitory control and downregulated the brain response to appetizing food images. Finally, in a PET-fMRI fusion analysis (n = 10), we disclosed the patterned correspondence between caudate glucose uptake and neuroactivity to reward and inhibition, showing that the secretin-induced neurometabolic coupling patterns promoted satiation.ConclusionThese findings suggest that secretin may modulate the BAT-brain metabolic crosstalk and subsequently the neurometabolic coupling to induce satiation. The study advances our understanding of the secretin signaling in motivated eating behavior and highlights the potential role of secretin in treating eating disorders and obesity.Trial registrationEudraCT no. 2016-002373-35, registered 2 June 2016; Clinical Trials no. NCT03290846, registered 25 September 2017.

GDF15 plays a critical role in insulin secretion in INS-1 cells and human pancreatic islets.

Mounting evidence points to a link between growth differentiation factor-15 (GDF15) expression and the onset and progression of diabetes mellitus. However, the exact role of GDF15 in pancreatic β-cell function is unclear. To examine the role of GDF15 in β-cell function, bioinformatics analysis and functional experiments involving GDF15 silencing and overexpression were performed in INS-1 cells and human islets. Public microarray and RNA-seq expression data showed that islets obtained from diabetic donors express high levels of GDF15 compared to islets obtained from normal donors. Moreover, analysis of RNA-seq expression data revealed that GDF15 expression correlates positively with that of insulin (INS), KCNJ11, GLUT1, MAFA, INSR and negatively with that of Glucokinase (GCK) and Alpha-Ketoglutarate Dependent Dioxygenase (FTO). No T2D-associated genetic variants in the GDF15 were found to pass genome-wide significance in the TIGER portal. Expression silencing of Gdf15 in INS-1 cells reduced insulin release, glucose uptake levels, increased reactive oxygen species (ROS) production and apoptosis levels. While Gdf15-silenced cells downregulated mRNA expression of Ins, Pdx1, Mafa, and Glut2 genes, its overexpression human islets was associated with increased insulin secretion and upregulated expression of MAFA and GLUT1 but not INS or GCK. Silencing of Pdx1 or Mafa in INS-1 cells did not affect the expression of GDF15. These findings suggest that GDF15 plays a significant role in pancreatic β-cell function.

S100A9 promotes glycolytic activity in HER2-positive breast cancer to induce immunosuppression in the tumour microenvironment

PurposeThe purpose of this study was to investigate the correlation between S100 calcium binding protein A9 (S100A9), tumour glycolysis and tumour infiltrating lymphocytes (TIL) in human epidermal growth factor receptor 2 (HER2) - positive breast cancer (BRCA). Materials and methodsA total of 667 BRCA patients in Xiangya Hospital of Central South University were enrolled in this study. Haematoxylin and eosin (H&E) staining were used to count TIN in tissues. Human breast cancer cell lines (SK-BR-3 cells and BT474 cells) were transfected with S100A9 specific small interfering RNA (siRNA). The expressions of S100A9, glycolytic enzymes and lymphocyte markers were detected by immunohistochemistry (IHC) staining, Western blot and immunofluorescence. Lactate production, glucose consumption and the extracellular acidification rate (ECAR) were detected to assess glycolysis activity. ResultsS100A9 was significantly overexpressed in HER2+ cases. The expressions of phosphoglycerol kinase 1 (PGK1), lactate dehydrogenase A (LDHA) and enolase α (ENO1) were significantly up-regulated in S100A9 dominant tissues. The expressions of PGK1, LDHA and ENO1 detected in S100A9 silenced cell lines were significantly down-regulated. Moreover, S100A9 silencing significantly altered lactate production, glucose uptake and ECAR levels in HER2+ cell lines. Co-expression of S100A9 and c-Myc was detected in HER2+ tissues. The absence of S100A9 greatly hindered β-catenin expression in cell lines, which later induced the phosphorylation of c-Myc.The amount of TILs in cases with abundant S100A9 and LDHA was much greater than in cases with low S100A9 levels and poorer LDHA. TIL deficiency and elevated S100A9 intensity are factors affecting the survival rate of HER2+ BRCA cases. ConclusionsS100A9 overexpression upregulated the glycolysis activity of tumour cells through the c-Myc-related pathway, suppressing lymphocyte infiltration in the tumour stroma, affecting the efficacy of immune regulation and long-term survival of patients.

Efficacy of the Hibiscus surattensis L. Leaves Active Fraction in Reducing the Levels of HbA1c, AGEs, and Glucose Uptake in Muscle Cells of Diabetic Type 2 Model Rat

Hibiscus surattensis L. is a traditional medicinal plant often used for diabetes treatment in Indonesia, especially in Central Sulawesi. The leaves contain mainly kaempferol, morine, and trifolin which have various pharmacological effects, including high antioxidant properties and the potential to increase insulin secretion. Therefore, this study aims to investigate the efficacy of the Hibiscus surattensis L. leaves (HSL) active fraction in reducing the levels of HbA1c, AGEs, and GLUT-4 expression in the muscle tissue of rat model with type 2 diabetes mellitus using a high-fat and fructose diet of 1.8 g/kg BW (HFD/HF) for 8 weeks. A total of 20 male rats were randomly assigned into four groups namely (1) normal control diet with standard rat chow; (2) negative control with HFD/HF diet; (3) treatment group with metformin 100 mg/kg BW as standard; (4) treatment group given HSL active fraction (FEA) 50 mg/kg BW. All treatments were given orally for 21 days and the data were analyzed by ANOVA and continued with the LSD post hoc test. HFD/HF induction significantly increased the HbA1c and AGEs levels 3.5 times and 1.88 times higher than the normal control group. Moreover, the treatments significantly reduced (p&lt;0.05) HbA1c and AGEs levels compared to the negative control on day 21. Blood HbA1C levels with FEA treatment decreased by 56.4%, while AGEs reduced by 54.7%. GLUT 4 expression in the muscle tissue was significantly different from the negative control with p&lt;0.05. The results also indicate that the administration of FEA had an antidiabetic effect by reducing the levels of HbA1C and AGEs along with other potentially beneficial effects on the treatment of type 2 DM with the probable mechanism of targeting GLUT4 glucose transporter by increasing its translocation and expression.

Metabolic features of naïve and memory CD4&lt;sup&gt;+&lt;/sup&gt;T cells in quiescence and during proliferation

Background. Memory CD4+ T cells proliferation is the basis for accelerated secondary immune response. The characteristics of memory CD4+ T cells providing their faster division compared to naive CD4+ T lymphocytes are poorly understood. T cells proliferative ability is determined by their metabolism. The metabolic features of proliferating memory CD4+ T cells remain elusive. The aim. To compare the metabolic features of naive and memory CD4+ T cells in quiescence and during proliferation. Methods. Peripheral blood mononuclear cells were analyzed using flow cytometry. Dividing cells were identified by CD71 expression. Cellular glucose and fatty acid uptake was assessed using fluorescent glucose (2-NBDG) and palmitate (BODIPY-FL-C16) analogs, respectively. Glutamine transporter expression was analyzed by staining the cells with anti-ASCT2 antibodies. Mitochondrial mass and membrane potential were measured using MitoTracker Green and MitoTracker Orange, respectively. Results. Quiescent memory CD4+ T cells exhibited elevated levels of glucose and palmitate uptake when compared to naive CD4 + T lymphocytes (p &lt; 0.001). Both subsets had increased substrate consumption when proceeding to proliferation (p &lt; 0.001). When dividing, naive CD4+ T cells consumed more glucose and palmitate than memory CD4+ T cell (p &lt; 0.001). Proliferation caused an increase in mitochondrial mass in naive (p &lt; 0.001) and memory CD4+ T lymphocytes (p &lt; 0.05). In memory CD4+ T cells, unlike naive CD4+ T lymphocytes, an increase in mitochondrial mass wasn’t accompanied by an increase in membrane potential. Conclusion. In memory CD4 + T cells, compared to naive CD4+ T lymphocytes, the metabolic change induced by proliferation is moderate and affects the mitochondrial activity to a lesser extent. Lower bioenergetic expenses of memory CD4+ T cells can contribute to their rapid proliferation during secondary immune response.

Scavenging Reactive Oxygen Species Decreases Amyloid-β Levels via Activation of PI3K/Akt/GLUT1 Pathway in N2a/APP695swe Cells.

Dysregulated glucose metabolism in the brain is considered to be one of the key causes of Alzheimer's disease (AD). Abnormal glucose uptake in AD is tightly associated with decreased levels of glucose transporter 1 (GLUT1) and GLUT3 in the brain, but the underlying mechanisms remain unclear. We aimed to explore the cause and mechanism of impaired glucose uptake in AD. N2a/WT and N2a/APP695swe cells were cultured in vitro, and cellular glucose uptake and ATP content, as well as the expression of GLUT1, GLUT3, and PI3K/Akt pathway members, were detected. Intracellular reactive oxygen species (ROS) levels were detected by flow cytometry. After treatment with the ROS scavenger N-acetyl-L-cysteine (NAC), the above indicators were detected again. GLUT1 expression was significantly decreased (p = 0.0138) in N2a/APP695swe cells, while GLUT3 expression was no statistical difference (p > 0.05). After NAC treatment, PI3K and Akt phosphorylation levels, GLUT1 expression, glucose uptake and ATP levels were remarkably increased (p = 0.0006, p = 0.0008, p = 0.0009, p = 0.0001, p = 0.0013), while Aβ levels were significantly decreased (p = 0.0058, p = 0.0066). After addition of the PI3K inhibitor LY29004, GLUT1 expression was reduced (p = 0.0008), and Aβ levels were increased (p = 0.0009, p = 0.0117). In addition, increases in glucose uptake and ATP levels induced by the Akt activator SC79 were hindered by the GLUT1 inhibitor WZB117 (p = 0.0002, p = 0.0005). Aβ levels were decreased after SC79 treatment and increased after WZB117 treatment (p = 0.0212, p = 0.0006). Taken together, scavenging of ROS prevents from Aβ deposition via activation of the PI3K/Akt/GLUT1 pathway, and improved the impaired glucose uptake in N2a/APP695swe cells.

Parthenolide targets NF-κB (P50) to inhibit HIF-1α-mediated metabolic reprogramming of HCC.

We focus on investigating the role of Parthenolide (Par), a small sesquiterpenoid molecule, in hepatocellular carcinoma (HCC) and its effective target.Highly-metastatic HCC cells, MHCC97-H, were divided into the DMSO and the Par groups, of which the Par group was intervened at 5 and 10 mg/L doses. Cell viability was assessed by CCK-8 assay. Transwell chamber assay was performed to examine the metastatic and invasive abilities, while plate clone formation assay was conducted to detect the clone formation ability. For analysis of glucose uptake, glycolytic ability and lactate level, the glycolysis assay was employed. Brdu staining was performed to evaluate the cell proliferative potential. The P50 and HIF-1α levels were measured by immunofluorescence, while the expressions of p-P50 and HIF-1α were determined by Western-Blot. Small molecule-protein docking and Pull-down experiments were conducted to validate the Par-P50 binding model. After establishing the tumor-bearing mouse model, Par was administered by gavage to measure the tissue levels of P50 and HIF-1α, followed by plotting of tumor growth curves.Par could inhibit the metastatic, invasive and clone formation abilities of MHCC97-H cells, reduce the cell proliferative potential, and suppress the glycolysis, as manifested by down-regulated level of lactate and reduced oxygen consumption. Meanwhile, Par inhibited the HIF-1α expression. We found that after silencing P50, the HIF-1α was down-regulated, the glycolytic ability decreased drastically, and the cellular metastatic and invasive abilities were suppressed. After P50 knockout, the effect of Par intervention on the MHCC97-H cells was reduced. In HCC-bearing mice, Par also exhibited an excellent anti-tumor effect, decreasing the tissue levels of P50 and HIF-1α.This study discovers that Par can inhibit the HIF-1α-mediated glycolysis of HCC cells by targeting P50, thereby exerting an anti-tumor effect. P50 is a major effective target of Par.

Aerobic glycolysis and tumor progression of hepatocellular carcinoma are mediated by ubiquitin of P53 K48-linked regulated by TRIM37

BackgroundHepatocellular carcinoma (HCC) is the most common primary liver cancer in the world. In malignant liver cancer, the increase of aerobic glycolysis indicates that the possibility of tumorigenesis is greatly enhanced. TRIM37 is a member of the TRIM family of proteins that possesses E3 ubiquitin ligase activity and has been implicated in the occurrence and prognosis of many different tumors. However, the stability of P53 plays an important role in preventing tumorigenesis. The mechanism by which TRIM37 regulates the stability of P53 through ubiquitin in the progression of hepatocellular carcinoma is still unclear. Materials and methodsReal-time quantitative polymerase chain reaction (qRT-PCR) and Western blotting were used to detect the expression of mRNA and protein in HCC cells. Lactic acid production, glucose uptake, and ATP levels were measured by BioVision kit. The following were used to assess the in vitro function of TRIM37 in HCC cells: cell counting kit-8 (CCK-8), colony formation assay, cell migration and invasion assay, and flow cytometry. We observed the effect of TRIM37 on the growth of transplanted tumors in nude mice. Co-Immunoprecipitation (Co-IP) revealed a binding relationship between TRIM37 and P53. ResultsThe expression of TRIM37 in hepatocellular carcinoma (HCC) tissues was higher than that of normal tissues according to an analysis of The Cancer Genome Atlas (TCGA) database.Loss-of-function assays indicated that TRIM37 inhibited the proliferation, colony formation, migration, and invasion of liver cancer cells. The mechanism is as follows: TRIM37 interacts with the P53 protein to induce E3 ligase activity, ubiquitination, and degradation, further promoting the malignant characteristics of hepatocellular carcinoma, thus promoting the process of glycolysis. Genetic knockdown of P53 reversed the promoting function of TRIM37 on the growth and metastasis of hepatocellular carcinoma cells. ConclusionsOur study showed that the TRIM37-P53 axis plays a role in the progression of liver cancer, and thus is a potential target for the treatment of liver cancer.