Expression Of Glucose Transporter Research Articles

Synaptotagmins family affect glucose transport in retinal pigment epithelial cells through their ubiquitination-mediated degradation and glucose transporter-1 regulation

BACKGROUND Synaptotagmins (SYTs) are a family of 17 membrane transporters that function as calcium ion sensors during the release of Ca2+-dependent neurotransmitters and hormones. However, few studies have reported whether members of the SYT family play a role in glucose uptake in diabetic retinopathy (DR) through Ca2+/glucose transporter-1 (GLUT1) and the possible regulatory mechanism of SYTs. AIM To elucidate the role of the SYT family in the regulation of glucose transport in retinal pigment epithelial cells and explore its potential as a therapeutic target for the clinical management of DR. METHODS DR was induced by streptozotocin in C57BL/6J mice and by high glucose medium in human retinal pigment epithelial cells (ARPE-19). Bioinformatics analysis, reverse transcriptase-polymerase chain reaction, Western blot, flow cytometry, ELISA, HE staining, and TUNEL staining were used for analysis. RESULTS Six differentially expressed proteins (SYT2, SYT3, SYT4, SYT7, SYT11, and SYT13) were found between the DR and control groups, and SYT4 was highly expressed. Hyperglycemia induces SYT4 overexpression, manipulates Ca2+ influx to induce GLUT1 fusion with the plasma membrane, promotes abnormal expression of the glucose transporter GLUT1 and excessive glucose uptake, induces ARPE-19 cell apoptosis, and promotes DR progression. Parkin deficiency inhibits the proteasomal degradation of SYT4 in DR, resulting in SYT4 accumulation and enhanced GLUT1 fusion with the plasma membrane, and these effects were blocked by oe-Parkin treatment. Moreover, dysregulation of the myelin transcription factor 1 (Myt1)-induced transcription of SYT4 in DR further activated the SYT4-mediated stimulus-secretion coupling process, and this process was inhibited in the oe-MYT1-treated group. CONCLUSION Our study reveals the key role of SYT4 in regulating glucose transport in retinal pigment epithelial cells during the pathogenesis of DR and the underlying mechanism and suggests potential therapeutic targets for clinical DR.

GHSR Deletion in β-Cells of Male Mice: Ineffective in Obesity, but Effective in Protecting against Streptozotocin-Induced β-Cell Injury in Aging

Insulin secretion from pancreatic β cells is a key pillar of glucose homeostasis, which is impaired under obesity and aging. Growth hormone secretagogue receptor (GHSR) is the receptor of nutrient-sensing hormone ghrelin. Previously, we showed that β-cell GHSR regulated glucose-stimulated insulin secretion (GSIS) in young mice. In the current study, we further investigated the effects of GHSR on insulin secretion in male mice under diet-induced obesity (DIO) and streptozotocin (STZ)-induced β-cell injury in aging. β-cell-specific-Ghsr-deficient (Ghsr-βKO) mice exhibited no glycemic phenotype under DIO but showed significantly improved ex vivo GSIS in aging. We also detected reduced insulin sensitivity and impaired insulin secretion during aging both in vivo and ex vivo. Accordingly, there were age-related alterations in expression of glucose transporter, insulin signaling pathway, and inflammatory genes. To further determine whether GHSR deficiency affected β-cell susceptibility to acute injury, young, middle-aged, and old Ghsr-βKO mice were subjected to STZ. We found that middle-aged and old Ghsr-βKO mice were protected from STZ-induced hyperglycemia and impaired insulin secretion, correlated with increased expression of insulin signaling regulators but decreased pro-inflammatory cytokines in pancreatic islets. Collectively, our findings indicate that β-cell GHSR has a major impact on insulin secretion in aging but not obesity, and GHSR deficiency protects against STZ-induced β-cell injury in aging.

Diabetes Causes Significant Alterations in Pulmonary Glucose Transporter Expression

Diabetes has been identified as a significant and independent risk factor for the development or increased severity of respiratory infections. However, the role of glucose transport in the healthy and diseased lung has received little attention. Specifically, the protein expression of the predominant glucose transporter (GLUT) isoforms in the adult lung remains largely to be characterized in both healthy and diabetic states. Type 1 diabetes was induced via streptozotocin and rescued via subcutaneous semi-osmotic insulin pump for 8 weeks. The gene and/or protein expression of the most predominant GLUT isoforms from Classes I and III, including the major insulin-sensitive isoform (i.e., GLUT4) and novel isoforms (i.e., GLUT-8 and GLUT-12), was quantified in the lung of healthy and diabetic mice via qRT-PCR and/or Western blotting. Pulmonary cell surface GLUT protein was measured using a biotinylated photolabeling assay, as a means to evaluate GLUT trafficking. Diabetic mice demonstrated significant alterations of total pulmonary GLUT protein expression, which were isoform- and location-dependent. Long-term insulin treatment rescued the majority of GLUT protein expression alterations in the lung during diabetes, as well as GLUT-4 and -8 trafficking to the pulmonary cell surface. These alterations in glucose homeostasis during diabetes may contribute to an increased severity of pulmonary infection during diabetes and may point to novel metabolic therapeutic strategies for diabetic patients with concurrent respiratory infections.

Temporal and regional expression changes and co-staining patterns of metabolic and stemness-related markers during glioblastoma progression.

Glioblastomas (GBMs) are characterized by high heterogeneity, involving diverse cell types, including those with stem-like features contributing to GBM's malignancy. Moreover, metabolic alterations promote growth and therapeutic resistance of GBM. Depending on the metabolic state, antimetabolic treatments could be an effective strategy. Against this background, we investigated temporal and regional expression changes and co-staining patterns of selected metabolic markers [pyruvate kinase muscle isozyme 1/2 (PKM1/2), glucose transporter 1 (GLUT1), monocarboxylate transporter 1/4 (MCT1/4)] in a rodent model and patient-derived samples of GBM. To understand the cellular sources of marker expression, we also examined the connection of metabolic markers to markers related to stemness [Nestin, Krüppel-like factor 4 (KLF4)] in a regional and temporal context. Rat tumour biopsies revealed a temporally increasing expression of GLUT1, higher expression of MCT1/4, Nestin and KLF4, and lower expression of PKM1 compared to the contralateral hemisphere. Patient-derived tumours showed a higher expression of PKM2 and Nestin in the tumour centre vs. edge. Whereas rare co-staining of GLUT1/Nestin was found in tumour biopsies, PKM1/2 and MCT1/4 showed a more distinct co-staining with Nestin in rats and humans. KLF4 was mainly co-stained with GLUT1, MCT1 and PKM1/2 in rat and human tumours. All metabolic markers yielded individual co-staining patterns among themselves. Co-staining mainly occurred later in tumour progression and was more pronounced in tumour centres. Also, positive correlations were found amongst markers that showed co-staining. Our results highlight a link between metabolic alterations and stemness in GBM progression, with complex distinctions depending on studied markers, time points and regions.

NREP, transcriptionally upregulated by HIF-1α, aggravates breast cancer cell growth and metastasis by promoting glycolysis

Breast cancer (BC) poses a great threat to women’s health. Neuronal regeneration related protein (NREP) is a multifunctional protein that is involved in embryonic development, regeneration, and human disease. However, the biological function of NREP in tumors is rarely reported and its role in BC remains unknown. Bioinformatics analysis showed that NREP is highly expressed and closely correlated with poor survival in BC patients. Under hypoxic conditions, NREP was upregulated in BC cells, and this promotion was reversed by hypoxia-inducible factor HIF-1α suppression. Luciferase reporter system and chromatin immunoprecipitation assays confirmed that HIF-1α directly binds to the promoter of NREP to increase the transcriptional activity of NREP. NREP suppression inhibited cell proliferation, arrested the cell cycle at the G1/S phase, and promoted apoptosis and caspase-3 activity in BC cells. Suppression of NREP decreased the tube formation ability of HUVECs. In addition, NREP downregulation showed an inhibition effect on cell migration, invasion, and EMT of BC cells. In NREP overexpressed cells, all these changes were reversed. In vivo, animal experiments also confirmed that NREP promotes BC tumor growth and metastasis. In addition, NREP promoted cellular glycolysis and enhanced the levels of glucose consumption, ATP, lactate production, and glucose transporters expression in NREP-overexpressed BC cells. In summary, our results demonstrated that NREP could be transcriptional activated by HIF-1α, which may aggravate BC tumor growth and metastasis by promoting cellular glycolysis. This result suggested that NREP may play an essential part in BC progression.

Electrochemiluminescent evaluation of GLUT4 expression in rat adipocytes induced by Ganoderma lucidum polysaccharides

Glucose transporter 4 (GLUT4) directly facilitates cellular uptake of glucose and plays a crucial role in mammalian adipose tissue glucose metabolism. In this work, we constructed a cytosensor for sensitive electrochemiluminescence (ECL) detection of GLUT4 in rat adipocytes (RA cells). A carbon nanotube sponge (CNTSP) was selected to fabricate a permeable electrode to overcome the steric hindrance of cells on the electrode. The expression of GLUT4 after treatment with Ganoderma lucidum polysaccharide (GLP) was assessed by analyzing the luminescence emitted from cell-surface ECL probes. Our preliminary results suggest that GLP promote the expression of GLUT4, thereby enhancing the uptake of the fluorescent glucose 2-NBDG. Treatment with GLP affected GLUT4 expression in RA cells in a dose-dependent manner. Additionally, the ECL cytosensor contributes to the development of ECL imaging of receptors on the cell surface for clinical drug evaluation.

Development of Aptamer-DNAzyme based metal-nucleic acid frameworks for gastric cancer therapy.

The metal-nucleic acid nanocomposites, first termed metal-nucleic acid frameworks (MNFs) in this work, show extraordinary potential as functional nanomaterials. However, thus far, realized MNFs face limitations including harsh synthesis conditions, instability, and non-targeting. Herein, we discover that longer oligonucleotides can enhance the synthesis efficiency and stability of MNFs by increasing oligonucleotide folding and entanglement probabilities during the reaction. Besides, longer oligonucleotides provide upgraded metal ions binding conditions, facilitating MNFs to load macromolecular protein drugs at room temperature. Furthermore, longer oligonucleotides facilitate functional expansion of nucleotide sequences, enabling disease-targeted MNFs. As a proof-of-concept, we build an interferon regulatory factor-1(IRF-1) loaded Ca2+/(aptamer-deoxyribozyme) MNF to target regulate glucose transporter (GLUT-1) expression in human epidermal growth factor receptor-2 (HER-2) positive gastric cancer cells. This MNF nanodevice disrupts GSH/ROS homeostasis, suppresses DNA repair, and augments ROS-mediated DNA damage therapy, with tumor inhibition rate up to 90%. Our work signifies a significant advancement towards an era of universal MNF application.

The protective role of endothelial GLUT1 in ischemic stroke.

To provide thorough insight on the protective role of endothelial glucose transporter 1 (GLUT1) in ischemic stroke. We comprehensively review the role of endothelial GLUT1 in ischemic stroke by narrating the findings concerning biological characteristics of GLUT1 in brain in depth, summarizing the changes of endothelial GLUT1 expression and activity during ischemic stroke, discussing how GLUT1 achieves its neuroprotective effect via maintaining endothelial function, and identifying some outstanding blind spots in current studies. Endothelial GLUT1 maintains persistent high glucose and energy requirements of the brain by transporting glucose through the blood-brain barrier, which preserves endothelial function and is beneficial to stroke prognosis. This review underscores the potential involvement of GLUT1 trafficking, activity modulation, and degradation, and we look forward to more clinical and animal studies to illuminate these mechanisms.

Fusobacterium periodonticum BCT protein targeting glucose metabolism to promote the epithelial-mesenchymal transition of esophageal cancer cells by lactic acid

BackgroundThe cancer microbiota was considered the main risk factor for cancer progression. We had proved that Fusobacterium periodonticum (F.p) was higher abundance in Esophageal cancer(EC)tissues. Bioinformation analysis found that BCT was a key virulence protein of F.p. However, little is known about the role and mechanism of BCT in EC. This study aimed to recognize the key virulence protein of F.p and explore the mechanism of BCT in promoting EC.MethodsWe constructed a eukaryotic expression vector and purified the recombinant protein BCT. CCK8 used to analyzed the activity of EC after treated by different concentration of BCT. UPLC-MS/MS and ELISA used to detect the metabonomics and metabolites. The ability of migration and invasion was completed by transwell assay. RT-QPCR, WB used to analyze the expression of relevant genes.ResultsOur data showed that BCT was higher expression in EC tumor tissues (p < 0.05) and BCT in 20 µg/mL promoted the survival, invasion and migration of EC cells (EC109) (p < 0.05). Meanwhile, UPLC-MS/MS results suggested that BCT resulted in an augmentation of hypotaurine metabolism, arachidonic acid metabolism, glycolysis/gluconeogenesis, tryptophan metabolism, citrate cycle activity in EC109. The metabolic changes resulted in decreasing in glucose and pyruvate levels but increase in lactate dehydrogenase (LDH) activity and lactic acid (LA) as well as the expression of glucose transporter 1, Hexokinase 2, LDH which regulated the glycolysis were all changed (p < 0.05). The BCT treatment upregulated the expression of TLR4, Akt, HIF-1α (p < 0.05) which regulated the production of LA. Furthermore, LA stimulation promoted the expression of GPR81, Wnt, and β-catenin (p < 0.05), thereby inducing EMT and metastasis in EC109 cells.ConclusionAltogether, these findings identified that impact of BCT in regulation of glycolysis in EC109 and its involves the TLR4/Akt/HIF-1α pathway. Meanwhile, glycolysis increasing the release of LA and promote the EMT of EC109 by GPR81/Wnt/β-catenin signaling pathway. In summary, our findings underscore the potential of targeting BCT as an innovative strategy to mitigate the development of EC.

The effect of coenzyme Q10 intake on metabolic profiles in women candidates for in vitro fertilization: A randomised trial

Objective: Infertility and the pathogenesis of polycystic ovarian syndrome (PCOS) are both influenced by insulin resistance and dyslipidemia. Presumably, adding CoQ10 to these patients’ diets will be beneficial. Therefore, this study aimed to examine the effects of CoQ10 supplementation on metabolic profiles in women candidates for in vitro fertilization (IVF). Trial design and methods: For this randomized, double-blinded, parallel, placebo-controlled clinical experiment, 40 PCOS-positive infertile women who were IVF candidates were included. They ranged in age from 18 to 40. The 20 participants in the two intervention groups received either CoQ10 or a placebo for 8 weeks. The expression of glucose transporter 1 (GLUT-1), peroxisome proliferator-activated receptor gamma (PPAR-γ), low-density lipoprotein receptor (LDLR) as well as metabolic profiles such as insulin metabolism and lipid profiles were evaluated. Quantitative RT-PCR determined the expression of GLUT-1, PPAR-γ, and LDLR on peripheral blood mononuclear cells. Lipid profiles and fasting glucose were assessed using enzymatic kits and insulin was determined using Elisa kit. Results: In comparison to the placebo, CoQ10 supplementation significantly reduced blood insulin levels (-0.3±1.0 vs. 0.5±0.7, P=0.01) and insulin resistance (-0.1±0.2 vs. 0.1±0.2, P=0.01), and increased PPAR-γ expression (P=0.01). In infertile PCOS patients’ candidates for IVF, CoQ10 supplementation showed no appreciable impact on other metabolic profiles. Also, CoQ10 supplementation revealed no significant impact on GLUT-1 (P=0.30), or LDLR (P=0.27) expression. Within-group changes in insulin levels (P=0.01) and insulin resistance (P=0.01) showed a significant elevation in the placebo group. When we adjusted the analysis for baseline BMI, baseline values of variables, and age, our findings were not affected. Conclusions: Eight weeks of CoQ10 supplementation demonstrated positive benefits on PPAR-γ expression, insulin resistance, and serum insulin in infertile PCOS women candidates for IVF.

Alteration of glucose metabolism and expression of glucose transporters in ovarian cancer.

Aerobic glycolysis also known as the Warburg effect, remains a hallmark of various cancers, including ovarian cancer. Cancer cells undergo metabolic changes to sustain their tumorigenic properties and adapt to environmental conditions, such as hypoxia and nutrient starvation. Altered metabolic pathways not only facilitate ovarian cancer cells' survival and proliferation but also endow them to metastasize, develop resistance to chemotherapy, maintain cancer stem cell phenotype, and escape anti-tumor immune responses. Glucose transporters (GLUTs), which play a pivotal role as the rate-limiting step in glycolysis, are frequently overexpressed in a variety of tumors, including ovarian cancer. Multiple oncoproteins can regulate GLUT proteins, promoting tumor proliferation, migration, and metastasis, either dependent or independent of glycolysis. This review examines the alteration of GLUT proteins, particularly GLUT1, in ovarian cancer and its impact on cancer initiation, progression, and resistance to treatment. Additionally, it highlights the role of these proteins as biomarkers for diagnosis and prognosis in ovarian cancer, and delves into novel therapeutic strategies currently under development that target GLUT isoforms.

2-Methoxyestradiol ameliorates doxorubicin-induced cardiotoxicity by regulating the expression of GLUT4 and CPT-1B in female rats.

The clinical usage of doxorubicin (DOX) is hampered due to cardiomyopathy. Studies reveal that estrogen (E2) modulates DOX-induced cardiotoxicity. Yet, the exact mechanism is unclear. The objective of the current study is to evaluate the influence of E2 and more specifically its metabolite 2-methoxyestradiol (2ME) on cardiac remodeling and the reprogramming of cardiac metabolism in rats subjected to DOX cardiotoxicity. Seventy-two female rats were divided into groups. Cardiotoxicity was induced by administering DOX (2.5 mg/kg three times weekly for 2 weeks). In some groups, the effect of endogenous E2 was abolished by ovariectomy (OVX) or by using the estrogen receptor (ER) blocker Fulvestrant (FULV). The effect of administering exogenous E2 or 2ME in the OVX group was studied. Furthermore, the influence of entacapone (COMT inhibitor) on induced cardiotoxicity was investigated. The evaluated cardiac parameters included ECG, histopathology, cardiac-related enzymes (creatine kinase isoenzyme-MB (CK-MB) and lactate dehydrogenase (LDH)), and lipid profile markers (total cholesterol (TC), triglyceride (TG), and high-density lipoprotein (HDL)). The expression levels of key metabolic enzymes (glucose transporter-4 (GLUT4) and carnitine palmitoyltransferase-1B (CPT-1B)) were assessed. Our results displayed that co-treatment of E2 and/or 2ME with DOX significantly reduced DOX-induced cardiomyopathy and enhanced the metabolism of the heart through the maintenance of GLUT4 and CPT-1B enzymes. On the other hand, co-treatment of DOX with OVX, entacapone, or FULV increased the toxic effect of DOX by further reducing these important metabolic enzymes. E2 and 2ME abrogate DOX-induced cardiomyopathy partly through modulation of GLUT 4 and CPT-1B enzymes.

GLUT3-mediated cigarette smoke-induced epithelial-mesenchymal transition in chronic obstructive pulmonary disease through the NF-kB/ZEB1 pathway

BackgroundAirway remodelling plays an important role in the pathogenesis of chronic obstructive pulmonary disease (COPD). Epithelial–mesenchymal transition (EMT) is a significant process during the occurrence of airway remodelling. Increasing evidence suggests that glucose transporter 3 (GLUT3) is involved in the epithelial mesenchymal transition (EMT) process of various diseases. However, the role of GLUT3 in EMT in the airway epithelial cells of COPD patients remains unclear.MethodsWe detected the levels of GLUT3 in the peripheral lung tissue of COPD patients and cigarette smoke (CS)-exposed mice. Two Gene Expression Omnibus GEO datasets were utilised to analyse GLUT3 gene expression profiles in COPD. Western blot and immunofluorescence were used to detect GLUT3 expression. In addition, we used the AAV9-GLUT3 inhibitor to reduce GLUT3 expression in the mice model. Masson’s staining and lung function measurement were used detect the collagen deposition and penh in the mice. A cell study was performed to confirm the regulatory effect of GLUT3. Inhibition of GLUT3 expression with siRNA, Western blot, and immunofluorescence were used to detect the expression of E-cadherin, N-cadherin, vimentin, p65, and ZEB1.ResultsBased on the GEO data set analysis, GLUT3 expression in COPD patients was higher than in non-smokers. Moreover, GLUT3 was highly expressed in COPD patients, CS exposed mice, and BEAS-2B cells treated with CS extract (CSE). Further research revealed that down-regulation of GLUT3 significantly alleviated airway remodelling in vivo and in vitro. Lung function measurement showed that GLUT3 reduction reduced airway resistance in experimental COPD mice. Mechanistically, our study showed that reduction of GLUT3 inhibited CSE-induced EMT by down-regulating the NF-κB/ZEB1 pathway.ConclusionWe demonstrate that CS enhances the expression of GLUT3 in COPD and further confirm that GLUT3 may regulate airway remodelling in COPD through the NF-κB/ZEB1 pathway; these findings have potential value in the diagnosis and treatment of COPD. The down-regulation of GLUT3 significantly alleviated airway remodelling and reduced airway resistance in vivo. Our observations uncover a key role of GLUT3 in modulating airway remodelling and shed light on the development of GLUT3-targeted therapeutics for COPD.

Metabolic reprogramming of the retinal pigment epithelium by cytokines associated with age-related macular degeneration.

The complex metabolic relationship between the retinal pigment epithelium (RPE) and photoreceptors is essential for maintaining retinal health. Recent evidence indicates the RPE acts as an adjacent lactate sink, suppressing glycolysis in the epithelium in order to maximize glycolysis in the photoreceptors. Dysregulated metabolism within the RPE has been implicated in the pathogenesis of age-related macular degeneration (AMD), a leading cause of vision loss. In the present study, we investigate the effects of four cytokines associated with AMD, TNFα, TGF-β2, IL-6, and IL-1β, as well as a cocktail containing all four cytokines, on RPE metabolism using ARPE-19 cells, primary human RPE cells, and ex vivo rat eyecups. Strikingly, we found cytokine-specific changes in numerous metabolic markers including lactate production, glucose consumption, extracellular acidification rate, and oxygen consumption rate accompanied by increases in total mitochondrial volume and ATP production. Together, all four cytokines could potently override the constitutive suppression of glycolysis in the RPE, through a mechanism independent of PI3K/AKT, MEK/ERK, or NF-κB. Finally, we observed changes in glycolytic gene expression with cytokine treatment, including in lactate dehydrogenase subunit and glucose transporter expression. Our findings provide new insights into the metabolic changes in the RPE under inflammatory conditions and highlight potential therapeutic targets for AMD.

GLUT3 transcriptional activation by ZEB1 fuels the Warburg effect and promotes ovarian cancer progression

Ovarian cancer (OvCa) is characterized by early metastasis and high mortality rates, underscoring the need for deeper understanding of these aspects. This study explores the role of glucose transporter 3 (GLUT3) driven by zinc finger E-box-binding homeobox 1 (ZEB1) in OvCa progression and metastasis. Specifically, this study explored whether ZEB1 promotes glycolysis and assessed the potential involvement of GLUT3 in this process in OvCa cells. Our findings revealed that ZEB1 and GLUT3 were excessively expressed and closely correlated in OvCa. Mechanistically, ZEB1 activates the transcription of GLUT3 by binding to its promoter region. Increased expression of GLUT3 driven by ZEB1 dramatically enhances glycolysis, and thus fuels Warburg Effect to promote OvCa progression and metastasis. Consistently, elevated ZEB1 and GLUT3 expression in clinical OvCa is correlated with poor prognosis, reinforcing the profound contribution of ZEB1-GLUT3 axis to OvCa. These results suggest that activation of GLUT3 expression by ZEB1 is crucial for the proliferation and metastasis of OvCa via fueling glycolysis, shedding new light on OvCa treatment.

AMPK restricts HHV-6A replication by inhibiting glycolysis and mTOR signaling

AMP-activated protein kinase (AMPK) is a cellular energy sensor regulating metabolic homeostasis. In this study, we investigated the role of AMPK in response to human herpesvirus 6A (HHV-6A) infection. We show that HHV-6A infection significantly downregulates the active phosphorylated state of AMPK in infected T cells. Pharmacological activation of AMPK highly attenuated HHV-6A propagation. Mechanistically, we found that the activation of AMPK by AICAR blocked HHV-6-induced glycolysis by inhibiting glucose metabolism and lactate secretion, as well as decreasing expressions of key glucose transporters and glycolytic enzymes. In addition, mTOR signaling has been inactivated in HHV-6A infected T cells by AICAR treatment. We also showed that HHV-6A infection of human umbilical cord blood mononuclear cells (CBMCs) reduced AMPK activity whereas the activation of AMPK by metformin drastically reduced HHV-6A DNA replication and virions production. Taken together, this study demonstrates that AMPK is a promising antiviral therapeutic target against HHV-6A infection.

Salvia officinalis Improves Glycemia and Suppresses Pro-inflammatory Features in Obese Rats with Metabolic Syndrome

Obesity is regarded as the main cause of metabolic diseases and a core factor for all-cause mortality in the general population, notably from cardiovascular disease. The majority of people with type 2 diabetes have obesity and insulin resistance. Some evidence indicates that an individual with obesity is approximately 10 times more likely to develop type 2 diabetes than someone with moderate body weight. One of the most significant therapeutic herbs, Salvia officinalis (Lamiaceae) (SAGE), possesses potent medicinal importance. The aim of this article was to evaluate the anti-diabetic and antiobesity activity of SAGEAE against HFD-induced obesity in rats. Thirty adult albino rats were randomly divided into five equal groups: control, High-fat Diet (HFD) administrated rats, HFD + Salvia officinalis Aqueous Extract (SAGEAE) (150 mg/kg.bw.), HFD + SAGEAE (300 mg/kg.bw.) and HFD + metformin (500 mg/kg.bw.). Body weight, plasma biochemical parameters, oxidative stress, inflammatory indicators, hepatic Phosphoenolpyruvate Carboxykinase 1 (PCK1), Glucokinase (GK), brain Leptin Receptor (LepRb), Glucose Transporter-4 (GLUT4), Sirtuin 1 (SIRT1) and mRNA33-5P gene signalling mRNA levels were all assessed after 8 weeks. A histological examination of the liver was also performed to check for lipid accumulation. The administration of HFD resulted in increased body weight, glucose, insulin, leptin, Total Cholesterol (TC), Triglycerides (TG), Thiobarbaturic Acid Reactive Substances (TBARS), Monocyte Chemoattractant Protein-1 (MCP1), Interleukine-6 (IL-6) and tumor necrosis factor-α (TNF- α) as well as hepatic PCK1, brain LepRb and adipose tissue mRNA33-5P gene expression. However, our findings revealed a significant reduction in adiponectin, High-density Lipoproteincholesterol (HDL-C), reduced glutathione (GSH) and Superoxide Dismutase (SOD) levels as well as the expression of hepatic GK and adipose tissue SIRT1 and GLUT4 genes. Also, administration of SAGEAE significantly normalized body weight, glucose, insulin, leptin, adiponectin, TC, TG, HDL-C, TBARs, SOD, IL-6, MCP-1 and TNF-α in plasma and liver tissue of HFD-treated rats. On the other hand, PCK1, GK, LepRb, SIRT1, GLUT4 and mRNA33-5P gene expression was enhanced in obese rats when administrated with SAGEAE. Histological and US studies support the biochemical, PCR and electrophoretic results. The findings imply that SAGEAE could be used as a new pharmaceutical formula in the treatment of obesity.

Effects of down-regulated carbonic anhydrase 8 on cell survival and glucose metabolism in human colorectal cancer cell lines.

Carbonic anhydrase 8 (CA8) is a member of the α-carbonic anhydrase family but does not catalyze the reversible hydration of carbon dioxide. In the present study, we examined the effects of CA8 on two human colon cancer cell lines, SW480 and SW620, by suppressing CA8 expression through shRNA knockdown. Our results showed that knockdown of CA8 decreased cell growth and cell mobility in SW620 cells, but not in SW480 cells. In addition, downregulated CA8 resulted in a significant decrease of glucose uptake in both SW480 and SW620 cells. Interestingly, stable downregulation of CA8 decreased phosphofructokinase-1 expression but increased glucose transporter 3 (GLUT3) levels in SW620 cells. However, transient downregulation of CA8 fails to up-regulate GLUT3 expression, indicating that the increased GLUT3 observed in SW620-shCA8 cells is a compensatory effect. In addition, the interaction between CA8 and GLUT3 was evidenced by pull-down and IP assays. On the other hand, we showed that metformin, a first-line drug for type II diabetes patients, significantly inhibited cell migration of SW620 cells, depending on the expressions of CA8 and focal adhesion kinase. Taken together, our data demonstrate that when compared to primary colon cancer SW480 cells, metastatic colon cancer SW620 cells respond differently to downregulated CA8, indicating that CA8 in more aggressive cancer cells may play a more important role in controlling cell survival and metformin response. CA8 may affect glucose metabolism- and cell invasion-related molecules in colon cancer, suggesting that CA8 may be a potential target in future cancer therapy.

Sourdough bread as nutritional intervention tool for improvement of cognitive dysfunction in diabetic rats

BackgroundThe current research targeted to study the impact of nutritional intervention by two sourdough breads in improvement of cognitive dysfunction in diabetic rats.MethodsType-2 diabetes was induced in rats by Streptozotocin-Nicotinamide (STZ-NC). Diabetic rats were fed on balanced diet or balanced diet containing 20% of sourdough bread I or II for a month. Lipid profile, oxidative stress, inflammatory markers and cognitive functions were assessed in all rats. Gene expression of brain-derived neurotrophic factor (BDNF) and nuclear respiratory factor 2 (NRF-2) were assessed in hippocampal tissue, while expression of phosphoenol pyruvate carboxy kinase (PEPCK), and glucose transporter 2 (GLUT2) genes were evaluated in hepatic tissue. Chemical composition and fatty acids profile were evaluated in the prepared sourdough bread.ResultsSourdough bread II showed higher content of phenolic compounds, fat, fiber and carbohydrates. Fatty acids profile revealed that sourdough bread I was higher in saturated fatty acids (16.08%), while sourdough bread sample II was higher in unsaturated fatty acids (79.33%). Sourdough bread I or II feeding rats’ showed significant improvement in hyperglycemia, oxidative stress markers, inflammatory markers, lipid profile, liver and kidney functions in association with improvement in cognitive function. Gene expression of BDNF and NRF2 in hippocampal tissue were increased significantly, while hepatic GLUT2 and PEPCK gene expression were down-regulated in diabetic given sourdough bread I or II.ConclusionSourdough bread II was superior in all the studied parameters. The anti-diabetic effect and protection from cognitive dysfunction of sourdough bread samples may be ascribed to the occurrence of dietary fibers, phenolic compounds, and polyunsaturated fatty acids.

Abstract 448: Alterations in glycolytic pathway enzymes and metabolic plasticity in prostate cancer progression

Abstract Background: Although oxidative phosphorylation (OXPHOS) is the main ATP source in primary prostate cancer, as the tumor progresses to castration resistance and/or metastatic disease, glycolysis becomes increasingly prevalent. Dependence on glycolysis can further increase under hypoxic conditions found in advanced cancers. We previously demonstrated that a novel small molecule, BKIDC-1553, inhibits proliferation and tumor growth of prostate cancer cell lines and xenografts through a hexokinase-2 (HK2) dependent inhibition of glycolysis. HK2 is a glucose 6-phosphorylating enzyme that works in conjunction with glucose transporter-1 (GLUT1) to drive glycolysis in cells. While our previous work suggests that BKIDC-1553 works primarily through a HK2 dependent mechanism, the objective of this current project is to further examine how expression and function of HK2 and GLUT1 are altered in response to BKIDC-1553 treatment. Methods: Hypoxic conditions are common in late-stage prostate cancer. Effects of hypoxia on cell proliferation and expression levels of HK1, HK2, and GLUT1 were examined with and without BKIDC-1553 treatment. To examine role of HK1, HK2, and GLUT1 in response to BKIDC-1553 treatment, we created CRISPR knockouts and shRNA knockdowns of HK1 and HK2 in the LNCaP prostate cancer cell line. GLUT1 was inhibited using a commercially available inhibitor, BAY-876. PCR and Western blots were used to confirm expression levels of HK1, HK2, and GLUT1. MTS proliferation assays were used to examine effect of KO and KD on response to BKIDC-1553 and BAY-876. Results: GLUT1 levels, but not HK1 or 2, increased at 72 hrs under hypoxic conditions. HK1, HK2, and GLUT1 levels all increased in cells in response to 144 hrs of BKIDC-1553 compared with 72 hrs treatment in both normoxic and hypoxic conditions. The KO and KD studies were all conducted in normoxic conditions. Westerns blots demonstrated that HK2 KO, but not HK1 KO, results in increased levels of GLUT1. HK1 or HK2 KD, however, did not alter GLUT1 levels. HK2 KD cells, with GLUT1 levels remaining the same, displayed less growth inhibition than control cells in response to BKIDC-1553 treatment, while HK2 KO cells, with increased levels of GLUT1, remained sensitive to BKIDC-1553. Because GLUT1 levels increase in response to HK2 KO, we wanted to see if inhibiting GLUT1 in these cells could decrease their proliferation. We found that KO cells were indeed more sensitive to growth inhibition of BAY-876. Conclusion/Summary: These studies indicate that KO of HK2 increases levels of GLUT1. These cells remain sensitive to BKIDC-1553 treatment, which could in part be due to the cells' continued reliance on glycolysis through increased GLUT1. A continued reliance on glycolysis allows BKIDC-1553 to continue to inhibit cell growth. Future studies examining how combination treatment with BKIDC-1553 and BAY-876 affects growth of advanced prostate cancer cells is underway. Citation Format: Cynthia Sprenger, Mika Munari, Shihua Sun, Kathryn Soriano Epilepsia, Stephen Plymate. Alterations in glycolytic pathway enzymes and metabolic plasticity in prostate cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 448.