Tumor-associated macrophages drive glycolysis through the IL-8/STAT3/GLUT3 signaling pathway in pancreatic cancer progression

Glycolytic metabolism is a hallmark of pancreatic ductal adenocarcinoma (PDAC), and tumor-associated stromal cells play important roles in tumor metabolism. We previously reported that tumor-associated macrophages (TAMs) facilitate PDAC progression. However, little is known about whether TAMs are involved in regulating glycolysis in PDAC. Here, we found a positive correlation between CD68+ TAM infiltration and FDG maximal standardized uptake (FDG SUVmax) on PET-CT images of PDAC. We discovered that the glycolytic gene set was prominently enriched in the high TAM infiltration group through Gene Set Enrichment Analysis using The Cancer Genome Atlas database. Mechanistically, TAMs secreted IL-8 to promote GLUT3 expression in PDAC cells, enhancing tumor glycolysis both in vitro and in vivo, whereas this effect could be blocked by the IL-8 receptor inhibitor reparixin. Furthermore, IL-8 promoted the translocation of phosphorylated STAT3 into the nucleus to activate the GLUT3 promoter. Overall, we demonstrated that TAMs boosted PDAC cell glycolysis through the IL-8/STAT3/GLUT3 signaling pathway. Our cumulative findings suggest that the abrogation of TAM-induced tumor glycolysis by reparixin might exhibit an antitumor impact and offer a potential therapeutic target for PDAC.

Fetal Hypoglycemia Induced by Placental SLC2A3-RNA Interference Alters Fetal Pancreas Development and Transcriptome at Mid-Gestation

Glucose, the primary energy substrate for fetal oxidative processes and growth, is transferred from maternal to fetal circulation down a concentration gradient by placental facilitative glucose transporters. In sheep, SLC2A1 and SLC2A3 are the primary transporters available in the placental epithelium, with SLC2A3 located on the maternal-facing apical trophoblast membrane and SLC2A1 located on the fetal-facing basolateral trophoblast membrane. We have previously reported that impaired placental SLC2A3 glucose transport resulted in smaller, hypoglycemic fetuses with reduced umbilical artery insulin and glucagon concentrations, in addition to diminished pancreas weights. These findings led us to subject RNA derived from SLC2A3-RNAi (RNA interference) and NTS-RNAi (non-targeting sequence) fetal pancreases to qPCR followed by transcriptomic analysis. We identified a total of 771 differentially expressed genes (DEGs). Upregulated pathways were associated with fat digestion and absorption, particularly fatty acid transport, lipid metabolism, and cholesterol biosynthesis, suggesting a potential switch in energetic substrates due to hypoglycemia. Pathways related to molecular transport and cell signaling in addition to pathways influencing growth and metabolism of the developing pancreas were also impacted. A few genes directly related to gluconeogenesis were also differentially expressed. Our results suggest that fetal hypoglycemia during the first half of gestation impacts fetal pancreas development and function that is not limited to β cell activity.

SLC2A3 promotes tumor progression through lactic acid-promoted TGF-β signaling pathway in oral squamous cell carcinoma

BACKGROUNDS

Oral squamous cell carcinoma is a malignant tumor of the head and neck, and its molecular mechanism remains to be explored.

METHODS

By analyzing the OSCC data from the TCGA database, we found that SLC2A3 is highly expressed in OSCC patients. The expression level of SLC2A3 was verified by RT-PCR and western blotting in OSCC cell lines. The function of SLC2A3 in OSCC cell lines and Lactic acid in SLC2A3-knockdown OSCC cells were detected by colony formation, CCK8, transwell, and wound healing assays. The effect of SLC2A3 on tumor growth and metastasis was tested in vivo. GSEA and Western blot were used to analyze and validate tumor phenotypes and signaling pathway molecules.

RESULTS

We analyzed OSCC datasets in the TCGA database and found that SLC2A3 had abnormally high expression and was associated with poor prognosis. We also found that oral squamous cell carcinoma cells had increased proliferation, migration, invasion, EMT phenotype, and glycolysis due to SLC2A3 overexpression. Conversely, SLC2A3 knockdown had the opposite effect. Our in vivo experiments confirmed that SLC2A3 overexpression promoted tumor growth and metastasis while knockdown inhibited it. We also observed that high SLC2A3 expression led to EMT and the activation of the TGF-β signaling pathway, while knockdown inhibited it. Interestingly, exogenous lactic acid restored the EMT, proliferation, migration, and invasion abilities of oral cancer cells inhibited by knocking down SLC2A3.

CONCLUSIONS

Our study reveals that SLC2A3 expression was up-regulated in OSCC. SLC2A3 activates the TGF-β signaling pathway through lactic acid generated from glycolysis, thus regulating the biological behavior of OSCC.

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.

Glut-3 Gene Knockdown as a Potential Strategy to Overcome Glioblastoma Radioresistance

The hypoxic pattern of glioblastoma (GBM) is known to be a primary cause of radioresistance. Our study explored the possibility of using gene knockdown of key factors involved in the molecular response to hypoxia, to overcome GBM radioresistance. We used the U87 cell line subjected to chemical hypoxia generated by CoCl2 and exposed to 2 Gy of X-rays, as single or combined treatments, and evaluated gene expression changes of biomarkers involved in the Warburg effect, cell cycle control, and survival to identify the best molecular targets to be knocked-down, among those directly activated by the HIF-1α transcription factor. By this approach, glut-3 and pdk-1 genes were chosen, and the effects of their morpholino-induced gene silencing were evaluated by exploring the proliferative rates and the molecular modifications of the above-mentioned biomarkers. We found that, after combined treatments, glut-3 gene knockdown induced a greater decrease in cell proliferation, compared to pdk-1 gene knockdown and strong upregulation of glut-1 and ldha, as a sign of cell response to restore the anaerobic glycolysis pathway. Overall, glut-3 gene knockdown offered a better chance of controlling the anaerobic use of pyruvate and a better proliferation rate reduction, suggesting it is a suitable silencing target to overcome radioresistance.

Altered Regulation of the Glucose Transporter GLUT3 in PRDX1 Null Cells Caused Hypersensitivity to Arsenite

Targeting tumour metabolism through glucose transporters is an attractive approach. However, the role these transporters play through interaction with other signalling proteins is not yet defined. The glucose transporter SLC2A3 (GLUT3) is a member of the solute carrier transporter proteins. GLUT3 has a high affinity for D-glucose and regulates glucose uptake in the neurons, as well as other tissues. Herein, we show that GLUT3 is involved in the uptake of arsenite, and its level is regulated by peroxiredoxin 1 (PRDX1). In the absence of PRDX1, GLUT3 mRNA and protein expression levels are low, but they are increased upon arsenite treatment, correlating with an increased uptake of glucose. The downregulation of GLUT3 by siRNA or deletion of the gene by CRISPR cas-9 confers resistance to arsenite. Additionally, the overexpression of GLUT3 sensitises the cells to arsenite. We further show that GLUT3 interacts with PRDX1, and it forms nuclear foci, which are redistributed upon arsenite exposure, as revealed by immunofluorescence analysis. We propose that GLUT3 plays a role in mediating the uptake of arsenite into cells, and its homeostatic and redox states are tightly regulated by PRDX1. As such, GLUT3 and PRDX1 are likely to be novel targets for arsenite-based cancer therapy.

GLUT3 regulates alternative macrophage signaling through a glucose transport-independent role

Macrophages are key mediators of innate immunity whose functional state can be regulated by glucose transporters. Although abundantly expressed in macrophages, the specific function of GLUT3, an isoform of facilitative glucose transporters, has not been clearly established. In this issue of the JCI, Dong-Min Yu and colleagues identify an alternative role for GLUT3 in promoting M2 macrophage polarization. The authors demonstrated that GLUT3 was upregulated upon M2 stimulation and was required for efficient alternative macrophage polarization and function. They further showed that GLUT3-induced M2 polarization was independent of glucose transport and functioned through Ras-mediated regulation of IL-4R endocytosis and IL-4/STAT6 activation. These findings may guide the development of macrophage-targeted treatments.

The effect of Apigenin on glycometabolism and cell death in an anaplastic thyroid cancer cell line

AIMS AND BACKGROUND

A more pronounced characteristic of cancer cells is the energy dependence on glucose, which mitigated by glucose transporters. The comprehension of the regulatory mechanisms behind the Warburg effect holds promise for developing therapeutic interventions for cancers. Studies are lacking which targeted the GLUTs for treatment of malignancy of thyroid tumors. In our current investigation, we have undertaken this study to determine the potential of Apigenin, plant derived flavonoid in modulating tumor apoptosis by targeting GLUTs expression in SW1736 cell line of anaplastic thyroid carcinoma.

MATERIAL METHODS

Flow cytometry with propidium iodide staining was used to determine cell apoptosis. For glucose uptake detection, the "GOD-PAP" enzymatic colorimetric test was used to measure the direct glucose levels inside the cells. To determine the expression of GLUT1 and GLUT3 mRNA in the SW1736 cell line qRT-PCR was employed. Protein levels of GLUT1 and GLUT3 in the SW1736 cell line were detected with western blotting. Also, the scratch wound healing assay was conducted for cell migration.

RESULTS

According to qRT-PCR analysis, the levels of GLUT1 and GLUT3 mRNA were lower in the group that received Apigenin relative to the control group. The Apigenin treatment of SW1736 cells decreased protein expression of the GLUT1 and GLUT3 levels in conformity to qRT-PCR. The scratch assays revealed that Apigenin treatment of cancer cell lines inhibited cell migration as compared to control.

CONCLUSION

These findings demonstrate the possibility of targeting the glucose facilitators' pathway for making thyroid cancer cells more susceptible to programmed cell death.

Correlations between class I glucose transporter expression patterns and clinical outcomes in non-small cell lung cancer

BACKGROUND

Glucose transporters (GLUTs) are highly expressed in various cancers. However, the implications of these variable expression patterns are unclear. This study aimed to clarify the correlation between class I GLUT expression patterns and clinical outcomes in non-small cell lung cancer (NSCLC), including their potential role in inflammatory signaling.

METHODS

Biopsy tissues from 132 patients with NSCLC (92 adenocarcinomas [ADC] and 40 squamous cell carcinomas [SQCC]) were analyzed. mRNA expression levels of class I GLUTs (solute carrier 2A [SLC2A]1, SLC2A2, SLC2A3, and SLC2A4) and inflammation-related molecules (toll-like receptors TLR4, RelA/p65, and interleukins IL8 and IL6) were measured. Cellular localization of GLUT3 and GLUT4 was investigated using immunofluorescence.

RESULTS

Single, combined, and negative GLUT (SLC2A) expression were observed in 27/92 (29.3%), 27/92 (29.3%), and 38/92 (41.3%, p < 0.001) of ADC and 8/40 (20.0%), 29/40 (72.5%, p < 0.001), and 3/40 (7.5%) of SQCC, respectively. In ADC, the single SLC2A3-expressed group had a significantly poorer prognosis, whereas the single SLC2A4-expressed group had a significantly better prognosis. The combined expression groups showed no significant difference. SLC2A expression was not correlated with SQCC prognosis. SLC2A4 expression correlated with lower IL8 expression. GLUT3 and GLUT4 expressions were localized in the tumor cytoplasm.

CONCLUSIONS

In lung ADC, single SLC2A3 expression correlated with poor prognosis, whereas single SLC2A4 expression correlated with better prognosis and lower IL8 expression. GLUT3 expression, which is increased by IL8 overexpression, may be suppressed by increasing the expression of GLUT4 through decreased IL8 expression.

Concurrent presence of diabetes affects the GLUT3 programming of glucose metabolism in glioblastoma

OBJECTIVE

Diabetes mellitus (DM)-mediated impaired glucose metabolism increase in the glioblastoma (GB) risk by inducing hyperglycemia and hyperinsulinemia. An integral membrane transport protein, glucose transporter 3 (GLUT3) facilitates glucose transport into GB tumor cells. We aimed to explore the regulation of GLUT3 in GB tumors of patients who were concurrently diagnosed with DM.

PATIENTS AND METHODS

Formalin-fixed paraffin-embedded (FFPE) tumor samples were collected from 93 GB patients and retrospectively analyzed. Of the total, 15 patients were concurrently diagnosed with DM (GB-DM). The role of GLUT3 in tumor aggressiveness was evaluated by analyzing its correlation with Ki67, P53 expression, MALAT1 expression, and peripheral blood hemoglobin A1C (HbA1c) level. T98G cells were treated with empagliflozin and metformin to modulate GLUT3. The RNA expression of GLUT3, SOX2, and MALAT1 was analyzed by real-time qPCR. The lactate levels of T98G cells were measured by Cobas c502 analyzer. A scratch wound assay was performed to investigate the migration rate of T98G cells.

RESULTS

GLUT3 expression was lower in GB-DM tumors than in GB-only tumors. In GB-DM, the expression of tumoral GLUT3 and peripheral blood glycated hemoglobin (HbA1c) levels were negatively correlated with P53 and Ki67. A decreased GLUT3 shortened the disease-free survival duration in GB-DM patients. Empagliflozin reduced GLUT3, while metformin-induced GLUT3 in T98G cells. The empagliflozin-mediated GLUT3 suppression induced SOX2 and MALAT1 expressions and influenced the migration capacity of T98G cells.

CONCLUSIONS

Our findings suggest that the low GLUT3 expression of the tumors of GB-DM patients may induce the production of adenosine triphosphate (ATP) from cellular energy sources other than glucose metabolism. However, further studies are warranted to confirm these results.

Differential role of neuronal glucose and PFKFB3 in memory formation during development

The consumption of glucose in the brain peaks during late childhood; yet, whether and how glucose metabolism is differentially regulated in the brain during childhood compared to adulthood remains to be understood. In particular, it remains to be determined how glucose metabolism is involved in behavioral activations such as learning. Here we show that, compared to adult, the juvenile rat hippocampus has significantly higher mRNA levels of several glucose metabolism enzymes belonging to all glucose metabolism pathways, as well as higher levels of the monocarboxylate transporters MCT1 and MCT4 and the glucose transporters endothelial-GLUT1 and GLUT3 proteins. Furthermore, relative to adults, long-term episodic memory formation in juvenile animals requires significantly higher rates of aerobic glycolysis and astrocytic-neuronal lactate coupling in the hippocampus. Only juvenile but not adult long-term memory formation recruits GLUT3, neuronal 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase 3 (PFKFB3) and more efficiently engages glucose in the hippocampus. Hence, compared to adult, the juvenile hippocampus distinctively regulates glucose metabolism pathways, and formation of long-term memory in juveniles involves differential neuronal glucose metabolism mechanisms.

Impact of Placental SLC2A3 Deficiency during the First-Half of Gestation

In the ruminant placenta, glucose uptake and transfer are mediated by facilitative glucose transporters SLC2A1 (GLUT1) and SLC2A3 (GLUT3). SLC2A1 is located on the basolateral trophoblast membrane, whereas SLC2A3 is located solely on the maternal-facing, apical trophoblast membrane. While SLC2A3 is less abundant than SLC2A1, SLC2A3 has a five-fold greater affinity and transport capacity. Based on its location, SLC2A3 likely plays a significant role in the uptake of glucose into the trophoblast. Fetal hypoglycemia is a hallmark of fetal growth restriction (FGR), and as such, any deficiency in SLC2A3 could impact trophoblast glucose uptake and transfer to the fetus, thus potentially setting the stage for FGR. By utilizing in vivo placenta-specific lentiviral-mediated RNA interference (RNAi) in sheep, we were able to significantly diminish (p ≤ 0.05) placental SLC2A3 concentration, and determine the impact at mid-gestation (75 dGA). In response to SLC2A3 RNAi (n = 6), the fetuses were hypoglycemic (p ≤ 0.05), exhibited reduced fetal growth, including reduced fetal pancreas weight (p ≤ 0.05), which was associated with reduced umbilical artery insulin and glucagon concentrations, when compared to the non-targeting sequence (NTS) RNAi controls (n = 6). By contrast, fetal liver weights were not impacted, nor were umbilical artery concentrations of IGF1, possibly resulting from a 70% increase (p ≤ 0.05) in umbilical vein chorionic somatomammotropin (CSH) concentrations. Thus, during the first half of gestation, a deficiency in SLC2A3 results in fetal hypoglycemia, reduced fetal development, and altered metabolic hormone concentrations. These results suggest that SLC2A3 may be the rate-limiting placental glucose transporter during the first-half of gestation in sheep.

Enforcing GLUT3 expression in CD8+ T cells improves fitness and tumor control by promoting glucose uptake and energy storage

Despite the tremendous success of adoptive T-cell therapies (ACT) in fighting certain hematologic malignancies, not all patients respond, a proportion experience relapse, and effective ACT of most solid tumors remains elusive. In order to improve responses to ACT suppressive barriers in the solid tumor microenvironment (TME) including insufficient nutrient availability must be overcome. Here we explored how enforced expression of the high-affinity glucose transporter GLUT3 impacted tumor-directed T cells. Overexpression of GLUT3 in primary murine CD8⁺ T cells enhanced glucose uptake and increased glycogen and fatty acid storage, and was associated with increased mitochondrial fitness, reduced ROS levels, higher abundance of the anti-apoptotic protein Mcl-1, and better resistance to stress. Importantly, GLUT3-OT1 T cells conferred superior control of B16-OVA melanoma tumors and, in this same model, significantly improved survival. Moreover, a proportion of treated mice were cured and protected from re-challenge, indicative of long-term T cell persistence and memory formation. Enforcing expression of GLUT3 is thus a promising strategy to improve metabolic fitness and sustaining CD8⁺ T cell effector function in the context of ACT.

Progesterone partially recovers placental glucose transporters in dexamethasone-induced intrauterine growth restriction

RESEARCH QUESTION

How does progesterone improve fetal outcome and change the expression of placental glucose transporters (GLUT) in dexamethasone-induced intrauterine growth restriction (IUGR)?

DESIGN

A total of 64 rats were divided randomly into four different treatment groups based on daily i.p. injections of either saline or dexamethasone in the presence or absence of progesterone. Injections started on the 15th day of gestation (15dg) and lasted until the day of sacrifice at 19dg or 21dg. Maternal plasma progesterone concentrations were measured by enzyme-linked immunosorbent assay. The gene and protein expression of placental GLUT1 and GLUT3 were evaluated in the placental labyrinth and basal zones by real-time polymerase chain reaction and Western blotting, respectively. The localization of GLUT1 and GLUT3 was evaluated by immunohistochemistry.

RESULTS

Dexamethasone induced significant decreases in maternal serum progesterone concentrations (P = 0.029) and placental (P < 0.001) and fetal body (P = 0.009) weights. Dexamethasone also reduced the expression of GLUT1 in the labyrinth zone (P = 0.028) and GLUT3 in both the labyrinth (P = 0.002) and basal zones (P = 0.026). Coadministration of dexamethasone and progesterone prevented the reduction in fetal body weight, placental weight and placental GLUT expression compared with that seen in dexamethasone-treated groups.

CONCLUSION

These results suggest that progesterone prevents the significant reduction in fetal and placental weights in dexamethasone-induced IUGR, possibly through improving the expression of placental GLUT.

Diet-induced obesity in mice impairs host defense against Klebsiella pneumonia in vivo and glucose transport and bactericidal functions in neutrophils in vitro

Obesity impairs host defense against Klebsiella pneumoniae, but responsible mechanisms are incompletely understood. To determine the impact of diet-induced obesity on pulmonary host defense against K. pneumoniae, we fed 6-wk-old male C57BL/6j mice a normal diet (ND) or high-fat diet (HFD) (13% vs. 60% fat, respectively) for 16 wk. Mice were intratracheally infected with Klebsiella, assayed at 24 or 48 h for bacterial colony-forming units, lung cytokines, and leukocytes from alveolar spaces, lung parenchyma, and gonadal adipose tissue were assessed using flow cytometry. Neutrophils from uninfected mice were cultured with and without 2-deoxy-d-glucose (2-DG) and assessed for phagocytosis, killing, reactive oxygen intermediates (ROI), transport of 2-DG, and glucose transporter (GLUT1-4) transcripts, and protein expression of GLUT1 and GLUT3. HFD mice had higher lung and splenic bacterial burdens. In HFD mice, baseline lung homogenate concentrations of IL-1β, IL-6, IL-17, IFN-γ, CXCL2, and TNF-α were reduced relative to ND mice, but following infection were greater for IL-6, CCL2, CXCL2, and IL-1β (24 h only). Despite equivalent lung homogenate leukocytes, HFD mice had fewer intraalveolar neutrophils. HFD neutrophils exhibited decreased Klebsiella phagocytosis and killing and reduced ROI to heat-killed Klebsiella in vitro. 2-DG transport was lower in HFD neutrophils, with reduced GLUT1 and GLUT3 transcripts and protein (GLUT3 only). Blocking glycolysis with 2-DG impaired bacterial killing and ROI production in neutrophils from mice fed ND but not HFD. Diet-induced obesity impairs pulmonary Klebsiella clearance and augments blood dissemination by reducing neutrophil killing and ROI due to impaired glucose transport.

Epithelial mesenchymal transition regulator TWIST1 transcription factor stimulates glucose uptake through upregulation of GLUT1, GLUT3, and GLUT12 in vitro

TWIST1 is a major regulator of epithelial mesenchymal transition process, essential in cancer metastasis. Cancer cells increase glucose uptake capabilities to meet their high energy requirements. In this study, we explored the potential role of TWIST1 on glucose transport into the 293T cells in an insulin-dependent and insulin-independent manner. For this purpose, the ectopic expression of TWIST1 was successfully performed by electroporation. The altered mRNA expressions of GLUT-1, -3, -4, and -12, insulin receptor (InsR), and insulin receptor substrate (IRS)-1 and -2 were assessed in control and TWIST1-overexpressing cells. Glucose uptake rates of the cells were evaluated by fluorometric glucose uptake assay. Our findings showed that the transcriptional expression levels of GLUT-1, -3, and -12 genes were significantly upregulated by TWIST1. However, TWIST1 did not alter the mRNA and protein expressions of the InsR, its substrates (IRS-1 and -2), and GLUT-4 genes in 293T cells which are main factors for insulin-stimulated glucose uptake pathway. Also, the glucose transport activities were significantly increased in TWIST1-overexpressing cells compared to controls due to fetal bovine serum (FBS) stimulation, but there was a slight non-significant difference in insulin stimulation. Thus, our data suggest that TWIST1 could promote glucose uptake independently of insulin and is possible to be evaluated as a metabolic marker in cancer. Further investigations are needed to clarify the precise molecular mechanisms underlying the cells' glucose uptake and consumption during tumorigenesis.

Effects of functional variants of vitamin C transporter genes on apolipoprotein E E4-associated risk of cognitive decline: The Nakajima study

Apolipoprotein E E4 (APOE4) is a risk factor for cognitive decline. A high blood vitamin C (VC) level reduces APOE4-associated risk of developing cognitive decline in women. In the present study, we aimed to examine the effects of functional variants of VC transporter genes expressed in the brain (SLC2A1, SLC2A3, and SLC23A2) on APOE4-associated risk of developing cognitive decline. This case–control study involved 393 Japanese subjects: 252 cognitively normal and 141 cognitively impaired individuals (87 mild cognitive impairment and 54 dementia). Database searches revealed that rs1279683 of SLC23A2, and rs710218 and rs841851 of SLC2A1 are functional variants that are significantly associated with the altered expression of the respective genes and genotyped as three single nucleotide variants (SNVs). When stratified by SNV genotype, we found a significant association between APOE4 and cognitive decline in minor allele carriers of rs1279683 (odds ratio [OR] 2.02, 95% CI, 1.05–3.87, p = 0.035) but not in the homozygote carriers of the major allele. Significant associations between APOE4 and cognitive decline were also observed in participants with major allele homozygotes of rs710218 (OR 2.35, 95% CI, 1.05–5.23, p = 0.037) and rs841851 (OR 3.2, 95% CI, 1.58–6.46, p = 0.0012), but not in minor allele carriers of the respective SNVs. In contrast, the three functional SNVs showed no significant effect on cognitive decline. Our results imply that functional SNVs of VC transporter genes can affect APOE4-associated risk of developing cognitive decline via altered VC levels in the brain.

Fructose-rich diet and walnut supplementation differently regulate rat hypothalamic and hippocampal glucose transporters expression

BACKGROUND

Nutritional modulations may be considered a strategy to protect mental health. Neuronal homeostasis is highly dependent on the availability of glucose, which represents the primary energy source for the brain. In this study, we evaluated the effects of walnut intake and fructose-rich diet on the expression of glucose transporters (GLUTs) in two rat brain regions: hypothalamus and hippocampus.

RESULTS

Our results show that walnut supplementation of fructose-fed animals restored the hypothalamic content of GLUT1 and GLUT3 protein. Furthermore, walnut intake did not affect increased hypothalamic GLUT2 content upon fructose consumption. These effects were accompanied by distinctive alterations of hippocampal GLUTs levels. Specifically, walnut intake increased GLUT1 content, whereas GLUT2 protein was decreased within the rat hippocampus after both individual and combined treatments.

CONCLUSION

Overall, our study suggests that walnut supplementation exerted modulatory effects on the glucose transporters within specific brain regions in the presence of developed metabolic disorder. © 2021 Society of Chemical Industry.

Co-expression and prognosis analyses of GLUT1-4 and RB1 in breast cancer

BACKGROUND

Current treatment methods for patients with triple-negative breast cancer (TNBC) are very limited, and the prognosis of TNBC is relatively poor. It has been reported that glucose transporter 1 (GLUT1) is overexpressed in breast cancer cells; however, its association with the prognosis is mostly unclear. Moreover, retinoblastoma gene 1 (RB1) might be used as a biomarker for the sensitivity of breast cancer cells to GLUT1 inhibitors, which brought us to the hypothesis that there might be a close correlation between the expression of GLUT1-4 and the expression of RB1.

METHODS

In this study, we systematically analyzed the co-expression of GLUT1-4 and the influence of GLUT1-4 gene expression on the prognosis of breast cancer using data mining methods. We also explored possible relationships between GLUT1-4 and RB1 expression in breast cancer tissues. We used public databases such as ONCOMINE, GEPIA, LinkedOmics, and COEXPEDIA.

RESULTS

According to the results, the mRNA expression of SLC2A1 was significantly higher in breast cancer, while the expression levels of SLC2A2-4 were downregulated. The results also indicate that GLUT1 expression does not have significant influence on the overall survival of patients with breast cancer. The mRNA expression of SLC2A1 and RB1 is significantly correlated, which means that tissues with high RB1 mRNA expression might have relatively higher mRNA expression of SLC2A1; however, further study analyzing their roles in the expression regulation pathways with human samples is needed to verify the hypothesis.

CONCLUSIONS

The mRNA expression of SLC2A1 was significantly higher in breast cancer. The overall survival of breast cancer patients wasn't significantly correlated with GLUT1-4 expression. The mRNA expression of SLC2A1 and RB1 is significantly correlated according to the analysis conducted in LinkedOmics. It provides reference for future possible individualized treatment of TNBC using GLUT1 inhibitors, especially in patients with higher mRNA expression of RB1. Further study analyzing the roles of these two genes in the regulation pathways is needed.

Berberine ameliorates neuronal AD-like change via activating Pi3k/PGCε pathway

IR (insulin resistance) in diabetic brain gave rise to the generation of toxic factor Aβ42 and axon collapse which were the marker of AD (Alzheimer's disease)-like lesions in the circumstance of diabetes mellitus. But the underling molecular mechanism was not clear. Chronic HGHI (high glucose and high insulin) exposure accelerates IR has been reported in type II diabetes models. Berberine has been shown to promising effect for IR in vitro and in vivo. This study demonstrates the protective effect and the underlying mechanism of berberine on HGHI-induced IR. HGHI-induced cells were used to mimic the hyperinsulinemia resulting in IR. Berberine was used to uncover the mechanisms for the treatment of hyperinsulinemia in IR model. Morris water maze (MWM), PET imaging, CCK8 assay, ELISA assay, glucose kits, microscopy, and western blot analysis were performed to evaluate the protective effects of berberine. Berberine-improved HGHI-induced IR was correlated with the increase of glucose application in neurons. Meanwhile, the expressions of Pi3K, as well as GLUT3, PKCε, and APP were downregulated in the model, while p-IRS Ser307 was upregulated compared with Normal group. Fortunately, these scenes were reversed by berberine administration. Furthermore, berberine decreased GSK3β Y216 expressions, inhibited the production of oligomer Aβ42 and extended neuronal axon. The monomeric berberine treatment improves IR that may be involved in glucose effective application, rectifying the related proteins of the aberrant insulin pathway. Additionally, it suppressed the generation of Aβ42 and ameliorated neuron axon damage. Finally, berberine improves DM (diabetes mellitus)-induced cognitive impairment.

Overexpression of GLUT3 promotes metastasis of triple-negative breast cancer by modulating the inflammatory tumor microenvironment

Triple-negative breast cancer (TNBC) exhibits a higher level of glycolytic capacity and are commonly associated with an inflammatory microenvironment, but the regulatory mechanism and metabolic crosstalk between the tumor and tumor microenvironment (TME) are largely unresolved. Here, we show that glucose transporter 3 (GLUT3) is particularly elevated in TNBC and associated with metastatic progression and poor prognosis in breast cancer patients. Expression of GLUT3 is crucial for promoting the epithelial-to-mesenchymal transition and enhancing invasiveness and distant metastasis of TNBC cells. Notably, GLUT3 is correlated with inflammatory gene expressions and is associated with M1 tumor-associated macrophages (TAMs), at least in part by C-X-C Motif Chemokine Ligand 8 (CXCL8). We found that expression of GLUT3 regulates CXCL8 production in TNBC cells. Secretion of CXCL8 participates in GLUT3-overexpressing TNBC cells-elicited activation of inflammatory TAMs, which further enhances GLUT3 expression and mobility of TNBC cells. Our findings demonstrate that aerobic glycolysis in TNBC not only promotes aggressiveness of tumor cells but also initiates a positive regulatory loop for enhancing tumor progression by modulating the inflammatory TME.

Analysis of glucose metabolism by 18F-FDG-PET imaging and glucose transporter expression in a mouse model of intracerebral hemorrhage

The relationship between cerebral glucose metabolism and glucose transporter expression after intracerebral hemorrhage (ICH) is unclear. Few studies have used positron emission tomography (PET) to explore cerebral glucose metabolism after ICH in rodents. In this study, we produced ICH in mice with an intrastriatal injection of collagenase to investigate whether glucose metabolic changes in 18F-fluoro-2-deoxy-D-glucose (FDG)-PET images are associated with expression of glucose transporters (GLUTs) over time. On days 1 and 3 after ICH, the ipsilateral striatum exhibited significant hypometabolism. However, by days 7 and 14, glucose metabolism was significantly higher in the ipsilateral striatum than in the contralateral striatum. The contralateral hemisphere did not show hypermetabolism at any time after ICH. Qualitative immunofluorescence and Western blotting indicated that the expression of GLUT1 in ipsilateral striatum decreased on days 1 and 3 after ICH and gradually returned to baseline by day 21. The 18F-FDG uptake after ICH was associated with expression of GLUT1 but not GLUT3 or GLUT5. Our data suggest that ipsilateral cerebral glucose metabolism decreases in the early stage after ICH and increases progressively in the late stage. Changes in 18F-FDG uptake on PET imaging are associated with the expression of GLUT1 in the ipsilateral striatum.

Single-cell metabolic imaging reveals a SLC2A3-dependent glycolytic burst in motile endothelial cells

Single-cell motility is spatially heterogeneous and driven by metabolic energy. Directly linking cell motility to cell metabolism is technically challenging but biologically important. Here, we use single-cell metabolic imaging to measure glycolysis in individual endothelial cells with genetically encoded biosensors capable of deciphering metabolic heterogeneity at subcellular resolution. We show that cellular glycolysis fuels endothelial activation, migration and contraction and that sites of high lactate production colocalize with active cytoskeletal remodelling within an endothelial cell. Mechanistically, RhoA induces endothelial glycolysis for the phosphorylation of cofilin and myosin light chain in order to reorganize the cytoskeleton and thus control cell motility; RhoA activation triggers a glycolytic burst through the translocation of the glucose transporter SLC2A3/GLUT3 to fuel the cellular contractile machinery, as demonstrated across multiple endothelial cell types. Our data indicate that Rho-GTPase signalling coordinates energy metabolism with cytoskeleton remodelling to regulate endothelial cell motility.

High NOV/CCN3 expression during high-fat diet pregnancy in mice affects GLUT3 expression and the mTOR pathway

We investigated the expression levels of nephroblastoma overexpressed [NOV or CCN3 (cellular communication network factor 3)] in the serum and placenta of pregnant women and of pregnant mice fed a high-fat diet (HFD), and its effect on placental glucose transporter 3 (GLUT3) expression, to examine its role in gestational diabetes mellitus (GDM). NOV/CCN3 expression was increased in the mouse serum during pregnancy. At gestational day 18, NOV/CCN3 protein expression was increased in the serum and placenta of the HFD mice compared with that of mice fed a normal diet. Compared with non-GDM patients, the patients with GDM had significantly increased serum NOV/CCN3 protein expression and placental NOV/CCN3 mRNA expression. Therefore, we hypothesized that NOV/CCN3 signaling may be involved in the pathogenesis of GDM. We administered NOV/CCN3 recombinant protein via intraperitoneal injections to pregnant mice fed HFD or normal diet. NOV/CCN3 overexpression led to glucose intolerance. Combined with the HFD, NOV/CCN3 exacerbated glucose intolerance and caused insulin resistance. NOV/CCN3 upregulates GLUT3 expression and affects the mammalian target of rapamycin (mTOR) pathway in the GDM environment in vivo and in vitro. In summary, our results demonstrate, for the first time, the molecular mechanism of NOV/CCN3 signaling in maternal metabolism to regulate glucose balance during pregnancy. NOV/CCN3 may be a potential target for detecting and treating GDM.NEW & NOTEWORTHY NOV/CCN3 regulates glucose homeostasis in mice during pregnancy. NOV/CCN3 upregulates GLUT3 expression and affects the mTOR pathway in the GDM environment in vivo and in vitro.

Lauric acid alleviates insulin resistance by improving mitochondrial biogenesis in THP-1 macrophages

Mitochondrial dysfunction plays a crucial role in the central pathogenesis of insulin resistance and type 2 diabetes mellitus. Macrophages play important roles in the pathogenesis of insulin resistance. Lauric acid is a 12-carbon medium chain fatty acid (MCFA) found abundantly in coconut oil or palm kernel oil and it comes with multiple beneficial effects. This research objective was to uncover the effects of the lauric acid on glucose uptake, mitochondrial function and mitochondrial biogenesis in insulin-resistant macrophages. THP-1 monocytes were differentiated into macrophages and induce insulin resistance, before they were treated with increasing doses of lauric acid (5 μM, 10 μM, 20 μM, and 50 μM). Glucose uptake assay, cellular ROS and ATP production assays, mitochondrial content and membrane potential assay were carried out to analyse the effects of lauric acid on insulin resistance and mitochondrial biogenesis in the macrophages. Quantitative RT-PCR (qRT-PCR) and western blot analysis were also performed to determine the expression of the key regulators. Insulin-resistant macrophages showed lower glucose uptake, GLUT-1 and GLUT-3 expression, and increased hallmarks of mitochondrial dysfunction. Interestingly, lauric acid treatment upregulated glucose uptake, GLUT-1 and GLUT-3 expressions. The treatment also restored the mitochondrial biogenesis in the insulin-resistant macrophages by improving ATP production, oxygen consumption, mitochondrial content and potential, while it promoted the expression of mitochondrial biogenesis regulator genes such as TFAM, PGC-1α and PPAR-γ. We show here that lauric acid has the potential to improve insulin sensitivity and mitochondrial dysregulation in insulin-resistant macrophages.

Effect of Zhenxin Xingshui Yizhi Fang on Aβ25-35 induced expression of related transporters in HBMEC cell model

ETHNOPHARMACOLOGICAL RELEVANCE

Aβ (β-amyloid) deposition and abnormal transport were suggested to be risk factors for Alzheimer's disease (AD). Zhenxin Xingshui Yizhi Fang (XSF), an ancient prescription in traditional Chinese medicine, was first recorded in Qianjin Yifang for treating palpitation, hypnosia, amnesia. It is reported that XSF could improve mice learning memory ability, reduce the deposition of senile plaques in hippocampus of rat brain. In this study, the neuroprotective effect of XSF against Aβ_25-35-induced apoptosis in cultured human brain microvascular endothelial cells (HBMEC) and its potential mechanism were investigated.

MATERIALS AND METHODS

HBMEC cells were treated with Aβ_25-35 to established neurotoxic cell model. After that, the cells were treated with 125, 250, 500 μg/mL XSF to observe the protective effect. The viability of HBMEC cells were evaluated by MTT assay, the Aβ_25-35-induced apoptosis was characterized by Hoechst-33258 and the activity of cysteinyl aspartate specific proteinase-3. The expression level of Aβ_1-42 in cells induced by Aβ_25-35 was measured by human Aβ_1-42 kit. Protein and mRNA expression levels of advanced glycation end products (RAGE), low density lipoprotein receptor-related protein 1 (LRP1), glucose transporter 1 and 3 (GLUT1 and GLUT3) were assayed by capillary electrophoresis immunoassay and quantitative real-time polymerase chain reaction analyses.

RESULTS

In Aβ_25-35 induced neurotoxic cells, the percentage of apoptotic cells, the concentration of Aβ_1-42 and CASPASE-3 activity, protein and mRNA expression levels of RAGE increased significantly, but that of LRP1, GLUT1 and GLUT3 significantly decreased. XSF could inhibit the apoptotic of cells, reduced the concentration of Aβ_1-42 and CASPASE-3 expression, downregulate RAGE and upregulate LRP1, GLUT1 and GLUT3 expression.

CONCLUSION

The results suggest that XSF can reduce the cytotoxicity of HBMEC induced by Aβ_25-35, inhibit apoptosis, and regulate the transport of Aβ on BBB and energy metabolism disorder in HBMEC.

Frequent copy number gains of SLC2A3 and ETV1 in testicular embryonal carcinomas

Testicular germ cell tumours (TGCTs) appear as different histological subtypes or mixtures of these. They show similar, multiple DNA copy number changes, where gain of 12p is pathognomonic. However, few high-resolution analyses have been performed and focal DNA copy number changes with corresponding candidate target genes remain poorly described for individual subtypes. We present the first high-resolution DNA copy number aberration (CNA) analysis on the subtype embryonal carcinomas (ECs), including 13 primary ECs and 5 EC cell lines. We identified recurrent gains and losses and allele-specific CNAs. Within these regions, we nominate 30 genes that may be of interest to the EC subtype. By in silico analysis of data from 150 TGCTs from The Cancer Genome Atlas (TCGA), we further investigated CNAs, RNA expression, somatic mutations and fusion transcripts of these genes. Among primary ECs, ploidy ranged between 2.3 and 5.0, and the most common aberrations were DNA copy number gains at chromosome (arm) 7, 8, 12p, and 17, losses at 4, 10, 11, and 18, replicating known TGCT genome characteristics. Gain of whole or parts of 12p was found in all samples, including a highly amplified 100 kbp segment at 12p13.31, containing SLC2A3. Gain at 7p21, encompassing ETV1, was the second most frequent aberration. In conclusion, we present novel CNAs and the genes located within these regions, where the copy number gain of SLC2A3 and ETV1 are of interest, and which copy number levels also correlate with expression in TGCTs.

Steroids Regulate SLC2A1 and SLC2A3 to Deliver Glucose Into Trophectoderm for Metabolism via Glycolysis

The conceptuses (embryo/fetus and placental membranes) of pigs require energy to support elongation and implantation, and amounts of glucose and fructose increase in the uterine lumen during the peri-implantation period. Conceptuses from day 16 of pregnancy were incubated with either 14C-glucose or 14C-fructose and amounts of radiolabeled CO2 released from the conceptuses measured to determine rates of oxidation of glucose and fructose. Glucose and fructose both transport into conceptuses, and glucose is preferentially metabolized in the presence of fructose, whereas fructose is actively metabolized in the absence of glucose and to a lesser extent in the presence of glucose. Endometrial and placental expression of glucose transporters SLC2A1, SLC2A2, SCL2A3, and SLC2A4 were determined. SLC2A1 messenger RNA (mRNA) and protein, and SLC2A4 mRNA were abundant in the uterine luminal epithelium of pregnant compared to cycling gilts, and increased in response to progesterone and conceptus-secreted estrogen. SLC2A2 mRNA was expressed weakly by conceptus trophectoderm on day 15 of pregnancy, whereas SLC2A3 mRNA was abundant in trophectoderm/chorion throughout pregnancy. Therefore, glucose can be transported into the uterine lumen by SLC2A1, and then into conceptuses by SLC2A3. On day 60 of gestation, the cell-specific expression of these transporters was more complex, suggesting that glucose and fructose transporters are precisely regulated in a spatial-temporal pattern along the uterine-placental interface of pigs to maximize hexose sugar transport to the pig conceptus/placenta.

A Key Role of DNA Damage-Inducible Transcript 4 (DDIT4) Connects Autophagy and GLUT3-Mediated Stemness To Desensitize Temozolomide Efficacy in Glioblastomas

DNA damage-inducible transcript 4 (DDIT4) is known to participate in various cancers, including glioblastoma multiforme (GBM). However, contradictory roles of DDIT4 exist in inducing cell death and possessing anti-apoptotic functions against cancer progression. Herein, we investigated DDIT4 signaling in GBM and temozolomide (TMZ) drug resistance. We identified that TMZ induced DDIT4 upregulation, leading to desensitization against TMZ cytotoxicity in GBM cells. Higher DDIT4 levels were found in glioma cells and mesenchymal-type GBM patients, and these higher levels were positively correlated with mesenchymal markers. Furthermore, patients with lower DDIT4 levels, especially O-6-methylguanine-DNA methyltransferase (MGMT)-methylated patients, exhibited better TMZ therapeutic efficacy. We determined that higher levels of 5 DDIT4-associated downstream genes, including SLC2A3 (also known as glucose transporter 3 (GLUT3)), can be used to predict a poor prognosis. Among these 5 genes, only GLUT3 was upregulated in both TMZ-treated and DDIT4-overexpressing cells. DDIT4-mediated GLUT3 expression was also identified, and its expression decreased TMZ's cytotoxicity. A significant correlation existed between DDIT4 and GLUT3. DDIT4 signaling was found to be involved in both glycolytic and autophagic pathways. However, GLUT3 only participated in the exhibition of DDIT4-mediated stemness, resulting from glycolytic regulation, but not in DDIT4-mediated autophagic signaling. Finally, we identified TMZ-upregulated activating transcription factor 4 (ATF4) as an upstream regulator of DDIT4-mediated GLUT3/stemness signaling and autophagy. Consequently, ATF4/DDIT4 signaling was connected to both autophagy and GLUT3-regulated stemness, which are involved in TMZ drug resistance and the poor prognoses of GBM patients. Targeting DDIT4/GLUT3 signaling might be a new direction for glioma therapy.

Hypoxia drives glucose transporter 3 expression through hypoxia-inducible transcription factor (HIF)-mediated induction of the long noncoding RNA NICI

Hypoxia-inducible transcription factors (HIFs) directly dictate the expression of multiple RNA species including novel and as yet uncharacterized long noncoding transcripts with unknown function. We used pan-genomic HIF-binding and transcriptomic data to identify a novel long noncoding RNA Noncoding Intergenic Co-Induced transcript (NICI) on chromosome 12p13.31 which is regulated by hypoxia via HIF-1 promoter-binding in multiple cell types. CRISPR/Cas9-mediated deletion of the hypoxia-response element revealed co-regulation of NICI and the neighboring protein-coding gene, solute carrier family 2 member 3 (SLC2A3) which encodes the high-affinity glucose transporter 3 (GLUT3). Knockdown or knockout of NICI attenuated hypoxic induction of SLC2A3, indicating a direct regulatory role of NICI in SLC2A3 expression, which was further evidenced by CRISPR/Cas9-VPR-mediated activation of NICI expression. We also demonstrate that regulation of SLC2A3 is mediated through transcriptional activation rather than posttranscriptional mechanisms because knockout of NICI leads to reduced recruitment of RNA polymerase 2 to the SLC2A3 promoter. Consistent with this we observe NICI-dependent regulation of glucose consumption and cell proliferation. Furthermore, NICI expression is regulated by the von Hippel-Lindau (VHL) tumor suppressor and is highly expressed in clear cell renal cell carcinoma (ccRCC), where SLC2A3 expression is associated with patient prognosis, implying an important role for the HIF/NICI/SLC2A3 axis in this malignancy.

Sevoflurane Induces Learning and Memory Impairment in Young Mice Through a Reduction in Neuronal Glucose Transporter 3

Sevoflurane, which is widely used in paediatric anaesthesia, induces neural apoptosis in the developing brain and cognitive impairment in young mammals. Glucose hypometabolism is the key pathophysiological modulator of cognitive dysfunction. However, the effects and mechanism of sevoflurane on cerebral glucose metabolism after its use as an anaesthetic and its complete elimination are still unknown. We therefore investigated the influence of sevoflurane on neuronal glucose transporter isoform 3 (GLUT3) expression, glucose metabolism and apoptosis in vivo and in vitro and on neurocognitive function in young mice 24 h after the third exposure to sevoflurane. Postnatal day 14 (P14) mice and neural cells were exposed to 3% sevoflurane 2 h daily for three days. We found that sevoflurane anaesthesia decreased GLUT3 gene and protein expression in the hippocampus and temporal lobe, consistent with a decrease in glucose metabolism in the hippocampus and temporal lobe observed by [18F] fluorodeoxyglucose positron emission tomography (18F-FDG PET). Moreover, sevoflurane anaesthesia increased the number of TUNEL-positive cells and the levels of Bax, cleaved caspase 3 and cleaved PARP and reduced Bcl-2 levels in the hippocampus and temporal lobe. Young mice exposed to sevoflurane multiple times also showed learning and memory impairment. In addition, sevoflurane inhibited GLUT3 expression in primary hippocampal neurons and PC12 cells. GLUT3 overexpression in cultured neurons ameliorated the sevoflurane-induced decrease in glucose utilization and increase in the apoptosis rate. These data indicate that GLUT3 deficiency may contribute to sevoflurane-induced learning and memory deficits in young mice.

Glucose Metabolism Is Required for Platelet Hyperactivation in a Murine Model of Type 1 Diabetes

Patients with type 1 diabetes mellitus (T1DM) have increased thrombosis and platelet activation. The mechanisms for platelet hyperactivation in diabetes are incompletely understood. T1DM is accompanied by hyperglycemia, dyslipidemia, and increased inflammation in addition to an altered hormonal milieu. In vitro analysis of platelets revealed that normal glucose reduces platelet activation whereas hyperglycemic conditions increase platelet activation. We therefore hypothesized that hyperglycemia increases platelet glucose utilization, which increases platelet activation to promote thrombosis. Glucose uptake and glycolysis were increased in platelets isolated from mice given streptozotocin (STZ) to induce T1DM in concert with induction of GLUT3. Platelets from STZ-induced diabetic mice exhibited increased activation after administration of protease-activated receptor 4 peptide and convulxin. In contrast, platelets isolated from GLUT1 and GLUT3 double-knockout (DKO) mice, which lack the ability to use glucose, failed to increase activation in hyperglycemic mice. Diabetic mice displayed decreased survival in a collagen/epinephrine-induced pulmonary embolism model of in vivo platelet activation relative to nondiabetic controls. Survival after pulmonary embolism was increased in diabetic DKO mice relative to nondiabetic controls. These data reveal that increased platelet glucose metabolism in vivo contributes to increased platelet activation and thrombosis in a model of T1DM.

Metastatic Colorectal Cancer Rewrites Metabolic Program Through a Glut3-YAP-dependent Signaling Circuit

Rationale: Cancer cells reprogram cellular metabolism to fulfill their needs for rapid growth and metastasis. However, the mechanism controlling this reprogramming is poorly understood. We searched for upregulated signaling in metastatic colorectal cancer and investigated the mechanism by which Glut3 promotes tumor metastasis. Methods: We compared RNA levels and glycolytic capacity in primary and metastatic colon cancer. The expression and association of Glut3 with clinical prognosis in colon cancer tissues was determined by immunohistochemistry. Glut3 gain-of-function and loss-of-function were established using colon cancer HCT116, HT29, and metastatic 116-LM cells, and tumor invasiveness and stemness properties were evaluated. Metabolomic profiles were analyzed by GC/MS and CE-TOF/MS. The metastatic burden in mice fed a high-fat sucrose diet was assessed by intravenous inoculation with Glut3 knockdown 116-LM cells. Results: Upregulation of glycolytic genes and glycolytic capacity was detected in metastatic colorectal cancer cells. Specifically, Glut3 overexpression was associated with metastasis and poor survival in colorectal cancer patients. Mechanistically, Glut3 promoted invasiveness and stemness in a Yes-associated protein (YAP)-dependent manner. Activation of YAP in turn transactivated Glut3 and regulated a group of glycolytic genes. Interestingly, the expression and phosphorylation of PKM2 were concomitantly upregulated in metastatic colorectal cancer, and it was found to interact with YAP and enhance the expression of Glut3. Importantly, a high-fat high-sucrose diet promoted tumor metastasis, whereas the inhibition of either Glut3 or YAP effectively reduced the metastatic burden. Conclusion: Activation of the Glut3-YAP signaling pathway acts as a master activator to reprogram cancer metabolism and thereby promotes metastasis. Our findings reveal the importance of metabolic reprogramming in supporting cancer metastasis as well as possible therapeutic targets.

Progesterone-induced miR-152 interferes with embryonic implantation by downregulating GLUT3 in endometrial epithelium

To investigate the role of progesterone-induced micro-RNA (miR)-152 in early embryonic development and implantation by regulating GLUT3 in endometrial epithelium, qRT-PCR was used to detect the expression of miR-152, GLUT1, and GLUT3 in the endometrial epithelial cells of female mice. GLUT1 and GLUT3 proteins were detected by immunohistochemical staining in the mouse endometrial epithelium. Bioinformatics prediction associated with a luciferase assay was performed to determine whether GLUT1 and GLUT3 are target genes of miR-152. Specific miR-152 mimics or inhibitors were transfected into the endometrial epithelial cells to, respectively, overexpress or downregulate miR-152. Next, the glucose concentration of uterine fluid was measured by conducting high-performance liquid chromatography in vivo, and the glucose uptake of the endometrial epithelial cells was observed using a fluorometric assay in vitro. Early embryonic development and implantation were also observed after the miR-152 mimics or inhibitors had been transfected. Embryo transfer was observed after the miR-152 mimic transfection. miR-152 was found to directly target and thereby downregulate GLUT3 expression. The expressions of both miR-152 and GLUT3 in the mouse endometrial epithelium had spatiotemporal characteristics on days 1-4 of pregnancy. miR-152 affected the glucose concentration of uterine fluid and the glucose uptake of endometrial epithelial cells. The transfection of specific miR-152 mimics led to impaired embryonic development and implantation. To conclude, in endometrial epithelial cells, progesterone-induced miR-152 downregulates GLUT3 at the posttranscriptional level to maintain a proper glucose concentration in the uterine fluid, which is necessary for early embryonic development and implantation.

High-fat diet affects pregestational adiposity and glucose tolerance perturbing gestational placental macronutrient transporters culminating in an obese offspring in wild-type and glucose transporter isoform 3 heterozygous null mice

We examined the effect of a high-fat diet (HFD) vs. control diet (CD) upon pregestational and gestational wild-type (wt) and glucose transporter (glut)3 heterozygous (glut3^+/-) female mice and observed an increase in pregestational body weights, white adiposity (wt > glut3^+/-), circulating cholesterol, and high-density lipoproteins, with glucose intolerance in both genotypes. The HFD-exposed offspring displayed reduced birth weight with catch up to CD-fed in wt vs. an increased birth weight persisting as such at weaning by day 21 in glut3^+/- mice. To decipher the mechanism behind this genotype-specific difference in the HFD offspring's phenotype, we first examined placental macronutrient transporters and noted HFD-induced increase in CD36 in wt with no change in other FATPs, sodium-coupled neutral amino acid transporters and system L amino acid transporter in both genotypes. In contrast, while placental Glut1 increased in both the genotypes, only Glut3 increased in the glut3^+/- genotype in response to HFD. Hence, we next assessed glut3^+/- embryonic (ES) cells under differing stressors of low glucose, hypoxia and inhibition of oxidative phosphorylation. Reduced Glut3-mediated glucose uptake in glut3^+/- vs. wt ES cells culminated in deficient growth. We conclude that maternal HFD affects the in utero growth potential of the offspring by altering placental CD36 and Glut1 concentrations. In contrast, a differential effect on placental Glut3 concentrations between glut3^+/- and wt genotypes is evident, with an increase occurring in the glut3^+/- genotype alone. Deficient Glut3 in ES cells interferes with glucose uptake, cell survival and growth being further exaggerated with low glucose, hypoxia and inhibition of oxidative phosphorylation.

Synaptic activity-induced glycolysis facilitates membrane lipid provision and neurite outgrowth

The formation of neurites is an important process affecting the cognitive abilities of an organism. Neurite growth requires the addition of new membranes, but the metabolic remodeling necessary to supply lipids for membrane expansion is poorly understood. Here, we show that synaptic activity, one of the most important inducers of neurite growth, transcriptionally regulates the expression of neuronal glucose transporter Glut3 and rate-limiting enzymes of glycolysis, resulting in enhanced glucose uptake and metabolism that is partly used for lipid synthesis. Mechanistically, CREB regulates the expression of Glut3 and Siah2, the latter and LDH activity promoting the normoxic stabilization of HIF-1α that regulates the expression of rate-limiting genes of glycolysis. The expression of dominant-negative HIF-1α or Glut3 knockdown blocks activity-dependent neurite growth in vitro while pharmacological inhibition of the glycolysis and specific ablation of HIF-1α in early postnatal mice impairs the neurite architecture. These results suggest that the manipulation of neuronal glucose metabolism could be used to treat some brain developmental disorders.

Downregulation of GLUT3 Promotes Apoptosis and Chemosensitivity of Acute Myeloid Leukemia Cells via EGFR Signaling

BACKGROUND

Glucose transporter 3 (GLUT3) plays an important role in tumor progression and drug resistance in numerous malignancies, including acute myeloid leukemia (AML). However, the effect of GLUT3 silencing on treatment of AML remains poorly understood. The purpose of this study was to investigate role of GLUT3 in proliferation and chemosensitivity of AML and its underlying mechanisms.

METHODS

The siRNA transfection was conducted using LipofectamineTM 2000. Quantitative real-time RT-PCR (qRT-PCR) and Western blot analyses were employed to measure the expression levels of mRNA and protein for GLUT3, respectively. The cytotoxic effects of siRNA and vincristine were determined using the MTT assay. Flow cytometry was performed to analyze apoptosis.

RESULTS

GLUT3 siRNA transfection significantly reduced expression levels of GLUT3 mRNA and protein, leading to a strong growth inhibition and enhanced apoptosis (P = 0.017) in AML cells. Moreover, treatment with GLUT3 siRNA, synergistically enhanced the cytotoxic and apoptotic effects of vincristine (P = 0.025). We further investigated the possible mechanism involved in regulation of GLUT3 in AML cell proliferation and apoptosis. We found that GLUT3 negatively regulates EGFR activity, as well as the expression of its downstream proteins.

CONCLUSION

Our results demonstrated that GLUT3 plays a fundamental role in the survival and resistance of AML cells to vincristine. Therefore, GLUT3 can be considered as an attractive target for gene therapy of AML patients and siRNA-mediated silencing of this gene may be a novel strategy in AML treatment.

Crystallization and Structural Determination of the Human Glucose Transporters GLUT1 and GLUT3

Overexpression, purification, and crystallization of eukaryotic membrane proteins represent a major challenge for structural biology. In recent years, we have solved the crystal structures of the human glucose transporters GLUT1 in the inward-open conformation at 3.17 Å resolution and GLUT3 in the outward-open and occluded conformations at 2.4 and 1.5 Å resolutions, respectively. Structural elucidation of these transporters in three distinct functional states reveal the molecular basis for the alternating access transport cycle of this prototypal solute carrier family. It established the molecular foundation for future dynamic and kinetic investigations of these GLUTs, and will likely facilitate structure-based ligand development. In this chapter, we present the detailed protocols of recombinant protein expression, purification, and crystallization of GLUT1 and GLUT3, which may help the pursuit of structural elucidation of other eukaryotic membrane proteins.

Dynamic Profiling of Insulin Secretion and ATP Generation in Isolated Human and Mouse Islets Reveals Differential Glucose Sensitivity

BACKGROUND/AIMS

Rodent islets are often used for basic science research but they do not always recapitulate signalling events in human islets. This study evaluated the glucose-dependent responses of human and mouse islets in terms of dynamic insulin secretion, metabolic coupling and the role of glucose transporters.

METHODS

Glucose-induced insulin secretion from isolated mouse and human islets was profiled by perifusion and islet ATP levels were measured by chemoluminescence assay. Glucose transporter expression was determined by qPCR and western blotting.

RESULTS

Human islets show a left-shifted glucose concentration-insulin secretion profile compared to mouse islets. These data are consistent with glucose transporter expression, with human islets expressing mainly GLUT1 and GLUT3, and GLUT2 being the predominant transporter in mouse islets. Using the GLUT1 inhibitor STF-31 we unveiled an important role for GLUT1 for differences in glucose-induced insulin secretion profiles observed between the two species.

CONCLUSION

The high affinity of GLUT1/3 for glucose reflects the left-shifted glucose-induced insulin secretory response of human islets and the impairment of insulin secretion from human islets after STF-31 treatment indicates an important role for GLUT1 in human islet stimulus-secretion coupling. Our data provide further insight into key differences between insulin secretion regulation in mouse and human islets.

Activation of brain glucose metabolism ameliorating cognitive impairment in APP/PS1 transgenic mice by electroacupuncture

An essential feature of Alzheimer's disease (AD) is implicated in brain energy metabolic impairment that is considered underlying pathogenesis of cognitive impairment. Therefore, therapeutic interventions to allay cognitive deficits that target energy metabolism may be an efficacy strategy in AD. In this study, we found that electroacupuncture (EA) at the DU20 acupoint obviously increased glucose metabolism in specific brain regions such as cortex, hippocampus, cingulate gyrus, basal forebrain septum, brain stem, and cerebellum in APP/PS1 transgenic mice by animal ¹⁸F-Fluoro-2-deoxy-D-Glucose (¹⁸F-FDG)/positron emission tomography (PET) imaging, accompanied by cognitive improvements in the spatial reference learning and memory and memory flexibility and novel object recognition performances. Further evidence shown energy metabolism occurred in neurons or non-neuronal cells of the cortex and hippocampus in terms of the co-location of GLUT3/NeuN and GLUT1/GFAP. Simultaneously, metabolic homeostatic factors were critical for glucose metabolism, including phosphorylated adenosine monophosphate-activated protein kinase (AMPK) and AKT serine/threonine kinase. Furthermore, EA-induced phosphorylated AMPK and AKT inhibited the phosphorylation level of the mammalian target of rapamycin (mTOR) to decrease the accumulation of amyloid-beta (Aβ) in the cortex and hippocampus. These findings are concluded that EA is a potential therapeutic target for delaying memory decline and Aβ deposition of AD. The AMPK and AKT are implicated in the EA-induced cortical and hippocampal energy metabolism, which served as a contributor to improving cognitive function and Aβ deposition in a transgenic mouse model of AD.

Effects of Lipoic Acid on High-Fat Diet-Induced Alteration of Synaptic Plasticity and Brain Glucose Metabolism: A PET/CT and 13C-NMR Study

High-fat diet (HFD)-induced obesity is accompanied by insulin resistance and compromised brain synaptic plasticity through the impairment of insulin-sensitive pathways regulating neuronal survival, learning, and memory. Lipoic acid is known to modulate the redox status of the cell and has insulin mimetic effects. This study was aimed at determining the effects of dietary administration of lipoic acid on a HFD-induced obesity model in terms of (a) insulin signaling, (b) brain glucose uptake and neuronal- and astrocytic metabolism, and (c) synaptic plasticity. 3-Month old C57BL/6J mice were divided into 4 groups exposed to their respective treatments for 9 weeks: (1) normal diet, (2) normal diet plus lipoic acid, (3) HFD, and (4) HFD plus lipoic acid. HFD resulted in higher body weight, development of insulin resistance, lower brain glucose uptake and glucose transporters, alterations in glycolytic and acetate metabolism in neurons and astrocytes, and ultimately synaptic plasticity loss evident by a decreased long-term potentiation (LTP). Lipoic acid treatment in mice on HFD prevented several HFD-induced metabolic changes and preserved synaptic plasticity. The metabolic and physiological changes in HFD-fed mice, including insulin resistance, brain glucose uptake and metabolism, and synaptic function, could be preserved by the insulin-like effect of lipoic acid.

Sex-Specific Life Course Changes in the Neuro-Metabolic Phenotype of Glut3 Null Heterozygous Mice: Ketogenic Diet Ameliorates Electroencephalographic Seizures and Improves Sociability

We tested the hypothesis that exposure of glut3+/- mice to a ketogenic diet ameliorates autism-like features, which include aberrant behavior and electrographic seizures. We first investigated the life course sex-specific changes in basal plasma-cerebrospinal fluid (CSF)-brain metabolic profile, brain glucose transport/uptake, glucose and monocarboxylate transporter proteins, and adenosine triphosphate (ATP) in the presence or absence of systemic insulin administration. Glut3+/- male but not female mice (5 months of age) displayed reduced CSF glucose/lactate concentrations with no change in brain Glut1, Mct2, glucose uptake or ATP. Exogenous insulin-induced hypoglycemia increased brain glucose uptake in glut3+/- males alone. Higher plasma-CSF ketones (β-hydroxybutyrate) and lower brain Glut3 in females vs males proved protective in the former while enhancing vulnerability in the latter. As a consequence, increased synaptic proteins (neuroligin4 and SAPAP1) with spontaneous excitatory postsynaptic activity subsequently reduced hippocampal glucose content and increased brain amyloid β1-40 deposition in an age-dependent manner in glut3+/- males but not females (4 to 24 months of age). We then explored the protective effect of a ketogenic diet on ultrasonic vocalization, sociability, spatial learning and memory, and electroencephalogram seizures in male mice (7 days to 6 to 8 months of age) alone. A ketogenic diet partially restored sociability without affecting perturbed vocalization, spatial learning and memory, and reduced seizure events. We conclude that (1) sex-specific and age-dependent perturbations underlie the phenotype of glut3+/- mice, and (2) a ketogenic diet ameliorates seizures caused by increased cortical excitation and improves sociability, but fails to rescue vocalization and cognitive deficits in glut3+/- male mice.

Apelin Controls Fetal and Neonatal Glucose Homeostasis and Is Altered by Maternal Undernutrition

The adequate control of glucose homeostasis during both gestation and early postnatal life is crucial for the development of the fetoplacental unit and adaptive physiological responses at birth. Growing evidences indicate that apelin and its receptor, APJ, which are expressed across a wide range of tissues, exert important roles in glucose homeostasis in adults. However, little is known about the function of the apelinergic system during gestation. In this study, we evaluated the activity of this system in rats, the role of apelin in fetal and neonatal glucose homeostasis, and its modulation by maternal food restriction. We found that 1) the apelinergic system was expressed at the fetoplacental interface and in numerous fetal tissues, 2) ex vivo, the placenta released high amounts of apelin in late gestation, 3) intravenous apelin injection in mothers increased the transplacental transport of glucose, and 4) intraperitoneal apelin administration in neonates increased glucose uptake in lung and muscle. Maternal food restriction drastically reduced apelinemia in both mothers and growth-restricted fetuses and altered the expression of the apelinergic system at the fetoplacental interface. Together, our data demonstrate that apelin controls fetal and neonatal glucose homeostasis and is altered by fetal growth restriction induced by maternal undernutrition.

Beyond the redox imbalance: Oxidative stress contributes to an impaired GLUT3 modulation in Huntington's disease

Failure in energy metabolism and oxidative damage are associated with Huntington's disease (HD). Ascorbic acid released during synaptic activity inhibits use of neuronal glucose, favouring lactate uptake to sustain brain activity. Here, we observe a decreased expression of GLUT3 in STHdhQ111 cells (HD cells) and R6/2 mice (HD mice). Localisation of GLUT3 is decreased at the plasma membrane in HD cells affecting the modulation of glucose uptake by ascorbic acid. An ascorbic acid analogue without antioxidant activity is able to inhibit glucose uptake in HD cells. The impaired modulation of glucose uptake by ascorbic acid is directly related to ROS levels indicating that oxidative stress sequesters the ability of ascorbic acid to modulate glucose utilisation. Therefore, in HD, a decrease in GLUT3 localisation at the plasma membrane would contribute to an altered neuronal glucose uptake during resting periods while redox imbalance should contribute to metabolic failure during synaptic activity.

Experimental and Theoretical Data on the Mechanism by Which Red Wine Anthocyanins Are Transported through a Human MKN-28 Gastric Cell Model

The gastric absorption of red wine anthocyanins was evaluated using a gastric MKN-28 cell barrier model. Anthocyanin transport was not affected by the presence of 4% ethanol and decreased with the increase of pH. Gastric cells pretreated with anthocyanins were found to increase anthocyanin transport. The presence of d-(+)-glucose was found to decrease anthocyanin uptake, suggesting the involvement of glucose transporters. RT-PCR assays revealed that GLUT1, GLUT3, and MCT1 transporters were expressed in MKN-28 cells. Computational studies were performed to provide a structural characterization of the binding site of hGLUT1 to glucose or different anthocyanins under different forms. Docking results demonstrated that anthocyanins can bind to glucose transporters from both intracellular and extracellular sides. Anthocyanins seem to enter into the transporter by two main conformations: B ring or glucose. From MD simulations, hGLUT1 was found to form complexes with all anthocyanins tested in the different protonation states.

Regulation of Human Trophoblast GLUT3 Glucose Transporter by Mammalian Target of Rapamycin Signaling

Glucose transporter isoform-3 (GLUT3), one of the primary placental facilitative glucose transporters responsible for basal glucose transport, has a crucial role in glucose transport and fetal growth during early pregnancy. A GLUT3 mutation in mice has been reported to cause loss of early pregnancy or late-gestational fetal growth restriction. However, the underlying mechanisms that regulate the placental GLUT3 transporter in humans are largely unknown. In the present study, we used the JEG-3 human choriocarcinoma cell line, which resembles a first trimester placental model, to study the role of the mammalian target of rapamycin complex 1 (mTORC1) in the regulation of placental GLUT3. We combined rapamycin treatment and small interfering (si) RNA-mediated silencing approaches with mRNA and protein expression/localization studies to investigate the alteration of GLUT3 expression and localization following mTORC1 inhibition in JEG-3 trophoblasts. Inhibition of mTORC1 signaling by silencing raptor decreased GLUT3 mRNA expression (−41%) and protein expression (−50%). Similar effects were obtained in cells in which mTORC1 was inhibited by rapamycin. Immunofluorescence analysis revealed that GLUT3 expression was markedly reduced in the cell surface and cytoplasm of JEG-3 cells in response to mTORC1 silencing. Because placental mTORC1 activity and GLUT3 expression are decreased in human intrauterine growth restriction, our data suggested one possible mechanism for the abnormal fetal growth in this pregnancy complication.

Iodide- and glucose-handling gene expression regulated by sorafenib or cabozantinib in papillary thyroid cancer

CONTEXT

The aberrant silencing of iodide-handling genes accompanied by up-regulation of glucose metabolism presents a major challenge for radioiodine treatment of papillary thyroid cancer (PTC).

OBJECTIVE

This study aimed to evaluate the effect of tyrosine kinase inhibitors on iodide-handling and glucose-handling gene expression in BHP 2-7 cells harboring RET/PTC1 rearrangement.

MAIN OUTCOME MEASURES

In this in vitro study, the effects of sorafenib or cabozantinib on cell growth, cycles, and apoptosis were investigated by cell proliferation assay, cell cycle analysis, and Annexin V-FITC apoptosis assay, respectively. The effect of both agents on signal transduction pathways was evaluated using the Western blot. Quantitative real-time PCR, Western blot, immunofluorescence, and radioisotope uptake assays were used to assess iodide-handling and glucose-handling gene expression.

RESULTS

Both compounds inhibited cell proliferation in a time-dependent and dose-dependent manner and caused cell cycle arrest in the G0/G1 phase. Sorafenib blocked RET, AKT, and ERK1/2 phosphorylation, whereas cabozantinib blocked RET and AKT phosphorylation. The restoration of iodide-handling gene expression and inhibition of glucose transporter 1 and 3 expression could be induced by either drug. The robust expression of sodium/iodide symporter induced by either agent was confirmed, and (125)I uptake was correspondingly enhanced. (18)F-fluorodeoxyglucose accumulation was significantly decreased after treatment by either sorafenib or cabozantinib.

CONCLUSIONS

Sorafenib and cabozantinib had marked effects on cell proliferation, cell cycle arrest, and signal transduction pathways in PTC cells harboring RET/PTC1 rearrangement. Both agents could be potentially used to enhance the expression of iodide-handling genes and inhibit the expression of glucose transporter genes.

Testicular Metabolic Reprogramming in Neonatal Streptozotocin-Induced Type 2 Diabetic Rats Impairs Glycolytic Flux and Promotes Glycogen Synthesis

Defects in testicular metabolism are directly implicated with male infertility, but most of the mechanisms associated with type 2 diabetes- (T2DM) induced male infertility remain unknown. We aimed to evaluate the effects of T2DM on testicular glucose metabolism by using a neonatal-streptozotocin- (n-STZ) T2DM animal model. Plasma and testicular hormonal levels were evaluated using specific kits. mRNA and protein expression levels were assessed by real-time PCR and Western Blot, respectively. Testicular metabolic profile was assessed by (1)H-NMR spectroscopy. T2DM rats showed increased glycemic levels, impaired glucose tolerance and hyperinsulinemia. Both testicular and serum testosterone levels were decreased, whereas those of 17β-estradiol were not altered. Testicular glycolytic flux was not favored in testicles of T2DM rats, since, despite the increased expression of both glucose transporters 1 and 3 and the enzyme phosphofructokinase 1, lactate dehydrogenase activity was severely decreased contributing to lower testicular lactate content. However, T2DM enhanced testicular glycogen accumulation, by modulating the availability of the precursors for its synthesis. T2DM also affected the reproductive sperm parameters. Taken together these results indicate that T2DM is able to reprogram testicular metabolism by enhancing alternative metabolic pathways, particularly glycogen synthesis, and such alterations are associated with impaired sperm parameters.

Genetic variations in the GLUT3 gene associated with myelomeningocele

OBJECTIVE

Our objectives were to examine the extent of described sequence variation in the glucose transporter 3 (GLUT3) gene in children with myelomeningocele (MM), identify novel variations in the GLUT3 gene in these children, and determine whether these variations may confer a risk of MM.

STUDY DESIGN

We sequenced the 10 exons of GLUT3, including exon-intron boundaries, on 96 children with MM. Sequencing was performed with Sanger methods and results analyzed with deoxyribonucleic acid analysis software. Frequencies of known single-nucleotide polymorphisms were identified, and those differing from the reference sequence (GRCh37/hg19 assembly) were considered variations.

RESULTS

Six novel and 9 previously described, genetic variations were identified in our population. The novel variations included a large, 83 base pair deletion involving the core promoter region and part of exon 1 (1 of 96 children), and a 2 base pair deletion in the coding sequence of exon 4 (1 of 96 children). The remaining novel variations were located in the introns in the proximity of the splice sites. Novel mutations in GLUT3 were observed among 6.25% of our population. Additionally, the frequency of the rare allele for rs17847972 located in a splice donor site is higher (P < .001) in MM in our population than expected.

CONCLUSION

We identified previously undescribed deletions and single-nucleotide variations involving the GLUT3 gene that may be associated with increased susceptibility to MM. Of particular interest, the 2 deletions involve both an important core promoter site and a coding region predicted to have a deleterious effect. The functional significance of these findings is under investigation.

Hyperglycemia induces memory impairment linked to increased acetylcholinesterase activity in zebrafish (Danio rerio)

Diabetes mellitus, which causes hyperglycemia, affects the central nervous system and can impairs cognitive functions, such as memory. The aim of this study was to investigate the effects of hyperglycemia on memory as well as on the activity of acethylcholinesterase. Hyperglycemia was induced in adult zebrafish by immersion in glucose 111mM by 14 days. The animals were divided in 4 groups: control, glucose-treated, glucose-washout 7-days and glucose-washout 14-days. We evaluated the performance in inhibitory avoidance task and locomotor activity. We also determined acethylcholinesterase activity and gene expression from whole brain. In order to counteract the effect of hyperglycemia underlined by effects on acethylcholinesterase activity, we treated the animals with galantamine (0.05ng/g), an inhibitor of this enzyme. Also we evaluated the gene expression of insulin receptor and glucose transporter from zebrafish brain. The hyperglycemia promoted memory deficit in adult zebrafish, which can be explained by increased AChE activity. The ache mRNA levels from zebrafish brain were decrease in 111mM glucose group and returned to normal levels after 7 days of glucose withdrawal. Insulin receptors (insra-1, insra-2, insrb-1 and insrb-2) and glut-3 mRNA levels were not significantly changed. Our results also demonstrated that galantamine was able to reverse the memory deficit caused by hyperglycemia, demonstrating that these effects involve modulation of AChE activity. These data suggest that the memory impairment induced by hyperglycemia is underlined by the cholinergic dysfunction caused by the mechanisms involving the control of acetylcholinesterase function and gene expression.