Glucose Metabolism-related Genes Research Articles

Intestinal microbiota contributes to altered glucose metabolism in simulated microgravity mouse model.

Exposure to space environment induces alterations in glucose and lipid metabolism that contribute to muscular atrophy, bone loss, and cardiovascular disorders. Intestinal microbiota is also changed, but its impact on spaceflight-related metabolic disorder is not clear. We investigated the relationship between glucose metabolic changes and gut dysbiosis in a hind limb-unloading (HU) mouse model, a well-accepted ground-based spaceflight analog. Impaired body weight gain, glucose intolerance, and peripheral insulin resistance were found in 2-4-wk HU mice. Reduced abundance of gut Bifidobacterium spp. and Akkermansia muciniphila was observed within 3 d of HU. The ground-based control (Ctrl) mice that were cohoused with HU mice showed similar patterns of dysbiosis and metabolic changes. Compared with the Ctrls, higher levels of plasma LPS-binding protein and altered transcription of Tnfa and glucose metabolism-related genes in the liver were observed in HU mice. The supplementation of Bifidobacterium spp. suppressed endotoxemia and liver inflammation and improved glucose tolerance in HU mice. The results indicate a close relationship between dysbiosis and altered glucose metabolism in the HU model and also emphasize the importance of evaluating intestinal microbiota in astronauts and its effect on glucose metabolism.-Wang, Y., Zhao, W., Shi, J., Wang, J., Hao, J., Pang, X., Huang, X., Chen, X., Li, Y., Jin, R., Ge, Q. Intestinal microbiota contributes to altered glucose metabolism in simulated microgravity mouse model.

Transcriptome Responses to Dexamethasone Depending on Dose and Glucocorticoid Receptor Sensitivity in the Liver.

Tissue sensitivity to glucocorticoids is a key factor dictating outcome of their homeostatic and therapeutic action, whereby liver represents one of the major peripheral targets. Here, we used pigs carrying a natural gain-of-function glucocorticoid receptor (GR) variant Ala610Val (GRAla610Val) as a model to identify genes and pathways related to differential glucocorticoid sensitivity. Animals with different GRAla610Val genotypes were treated either with saline or two different doses of dexamethasone. Genome-wide transcriptional responses depending on treatment, genotype, and their interaction in the liver were investigated using mRNA sequencing. Dexamethasone induced vast transcriptional responses, with more than 30% of present genes being affected. Functional annotation of genes differentially expressed due to dexamethasone treatment suggested that genes related to inflammation respond more sensitively, despite absence of an immune stimulus. In contrast, genes involved in glucose metabolism and cancer appeared to be less sensitive. Analysis of genotype and genotype × treatment interaction revealed that clustered protocadherins, particularly PCDHB7, are most prominently affected by GRAla610Val, mainly depending on dose. GRAla610Val influenced also expression of a set of glucose metabolism related genes, including PPARGC1A and CEBPB, in the absence of dexamethasone though no differences in basal plasma glucose level were observed. This might represent an adaptive response, keeping balance between receptor sensitivity, and level of circulating endogenous glucocorticoids. Administration of low dexamethasone dose changed their expression pattern and induced higher glucose response in carriers of the hypersensitive Val receptor. Our findings suggest that GRAla610Val modulates tissue responses to glucocorticoids dynamically, depending on their circulating level.

2,4-Thiazolidinedione in Well-Fed Lactating Dairy Goats: I. Effect on Adiposity and Milk Fat Synthesis.

Background: In a prior experiment, treatment of goats with the putative PPARγ agonist 2,4-thiazolidinedione (2,4-TZD) did not affect milk fat or expression of milk-fat related genes. The lack of response was possibly due to deficiency of vitamin A and/or a poor body condition of the animals. In the present experiment, we tested the hypothesis that PPARγ activation affects milk fat synthesis in goats with a good body condition and receiving adequate levels of vitamin A. Methods: Lactating goats receiving a diet that met NRC requirements, including vitamin A, were injected with 8 mg/kg BW of 2,4-TZD (n = 6) or saline (n = 6; CTR) daily for 26 days. Blood metabolic profiling and milk yield and components were measured including fatty acid profile. Expression of genes related to glucose and lipid metabolism was measured in adipose tissue and in mammary epithelial cells (MEC). Size of adipocytes was assessed by histological analysis. Results: NEFA, BHBA, and fatty acids available in plasma decreased while glucose increased in 2,4-TZD vs. CTR. Size of cells and expression of insulin signaling and glucose metabolism-related genes were larger in 2,4-TZD vs. CTR in adipose tissue. In MEC, expression of SCD1 and desaturation of stearate was lower in 2,4-TZD vs. CTR. Conclusions: Overall data revealed a lack of PPARγ activation by 2,4-TZD and no effect on milk fat synthesis despite a strong anti-lipolysis effect on adipose tissue.

Consequences on Gametogenesis and Reproduction Performances of a High Carbohydrate Nutrition During the Whole Reproductive Cycle of Male and Female Trout

Salmonids and more particularly rainbow trout are carnivorous species, and thus usually consider as glucose‐intolerant (GI) species and poor user of dietary carbohydrates displaying a decrease in growth and a persistent postprandial hyperglycaemia when fish meal is substituted at more than 20% by digestible carbohydrates in the diet. Nevertheless, these findings were mainly deduced from experiments conducted on immature juvenile trout and only scarce data are available in sexually mature males and females. In this regard, we investigated the impact of a high carbohydrate diet (HC diet) on gametogenesis and reproductive performances of 2 year‐old broodstocks fed with such a diet a whole year. Our results showed that both males and females ate and growth well when fed the HC diet even if, at the end of the trial, males, but not females, displayed growth retardation compared to control males. The glycaemia of fish fed the HC diet was higher than fish fed the control diet independently of the sex but these fish were not hyperglycaemic. Surprisingly, both sex displayed a precocious maturation. Whole body and gonads biochemical composition of fish did not differ during the whole year from one treatment to the other whereas liver of fish fed the HC diet retained more glycogen but less proteins compared to the control fish. We also monitored glucose metabolism modifications at the molecular level in both livers and gonads at different gametogenesis time points. Our results demonstrated that glucose metabolism strongly varied in female liver during gametogenesis independently of the diet whereas in male no significant difference where found. By contrast in both ovaries and testis, glucose metabolism related genes were found differentially expressed during gametogenesis but independently again of the diet. At spawning period, we performed cross‐fertilization between groups. For the 4 groups, both fertilization and early developmental rate were equivalent from one group to the other. In overall, our results highlight strong but sex‐dependent effects of a high carbohydrate diet on both oogenesis and spermatogenesis and a variation of glucose metabolism in both liver and gonads. However, these effects do not seem to affect reproductive performances.Support or Funding InformationThis study was supported by the French National Research Agency (ANR‐18‐CE20‐0012‐01 ‘SweetSex’).This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

MiR-200a-5p augments cardiomyocyte hypertrophy induced by glucose metabolism disorder via the regulation of selenoproteins.

Selenium and selenoproteins are identified as potential determinants in pathological cellular hypertrophy. Cardiomyocytes hypertrophy is a compensatory form of heart disease characterized by increased size of cardiomyocytes. However, the link between cardiac hypertrophy and Se-specific microRNA (miRNA) remains to be characterized. In the current study, we established a miR-200a-5p mimic and an inhibitor cardiomyocytes model. Cardiomyocytes hypertrophy was induced in the miR-200a-5p mimic group. Hence, we detected the glucose level of cardiomyocytes to estimate the cellular glucose uptake. The effect of miR-200a-5p overexpression and the low expression on 25 selenoproteins mRNA levels was further explored using reverse transcription polymerase chain reaction. Overexpression of miR-200a-5p elevated glucose uptake and Txnrd2, 3 expression and reduced Sepp1, Seln, Selt, and Sep15 expression in cardiomyocytes. Contrary results were observed in cardiomyocytes with the knockdown of miR-200a-5p. We next assessed glucose metabolism-related genes in cardiomyocytes. The results showed that miR-200a-5p had a negative correlation with insulin-like growth factor gene-1, insulin-like growth factor binding protein (IGFBP)1, IGFBP2, IGFBP3, IGFBP4, and IGFBP5 and had a positive correlation with Akt, glucose transporter family (GLUT)2, GLUT3, and GLUT4. These results support the involvement of selenoproteins and glucose metabolism in the control of cardiomyocytes hypertrophy by Se-specific miRNA, suggesting that miR-200a-5p inhibited the expression of stress-related selenoproteins to alter glucose transport leading to glucose metabolism disorder, eventually inducing cardiomyocytes hypertrophy. Our finding highlights a pivotal role of Se-specific miRNA and selenoproteins in cardiac hypertrophy.

Single-cell RNA sequencing reveals distinct gene expression patterns in glucose metabolism of human preimplantation embryos.

Precise regulation of glucose metabolism-related genes is essential for early embryonic development. Although previous research has yielded detailed information on the biochemical processes, little is yet known of the dynamic gene expression profiles in glucose metabolism of preimplantation embryos at a single-cell resolution. In the present study, we performed integrated analysis of single-cell RNA sequencing (scRNA-seq) data of human preimplantation embryos that had been cultured in sequential medium. Different cells in the same embryo have similar gene expression patterns in glucose metabolism. During the switch from the cleavage to morula stage, the expression of glycolysis-related genes, such as glucose transporter genes (solute carrier family 2 (facilitated glucose transporter), member 1 (SLC2A1) and solute carrier family 2 (facilitated glucose transporter), member 3 (SLC2A3) and genes encoding hexokinase, phosphofructokinase, pyruvate kinase and lactate dehydrogenase, is increased. The genes involved in the pentose phosphate pathway are highly expressed at the cleavage stage, generating the reducing power to balance oxidative stress derived from biosynthesis. Expression of the genes involved in the biosynthesis of glycerophospholipids is increased after the morula stage. Nevertheless, the expression of tricarboxylic acid-related genes remains relatively unchanged during the preimplantation stages. In conclusion, we discovered that the gene expression profiles are dynamic according to glucose utilisation in the embryos at different stages, which contributes to our understanding of regulatory mechanisms of glucose metabolism-related genes in human preimplantation embryos.

Chicoric acid mitigates impaired insulin sensitivity by improving mitochondrial function.

Mitochondrial dysfunction is associated with insulin resistance. Although chicoric acid (CA) is known to have beneficial effects on insulin sensitivity, the involvement of mitochondrial function has not been elucidated yet. Here, we investigated the effect of CA on insulin resistance and mitochondrial dysfunction. In palmitate-induced insulin-resistant C2C12 myotubes, CA improved impaired glucose uptake and insulin signaling pathways, along with enhanced mitochondrial membrane potential and oxygen consumption. CA treatment in diet-induced obese mice ameliorated glucose tolerance and increased insulin sensitivity. CA treatment also recovered the dysregulated expression of glucose metabolism-related genes in the high-fat-fed mice. CA significantly increased the mitochondrial DNA content, citrate synthase, and ATP content, as well as the expression of genes related to mitochondrial biogenesis and oxidative phosphorylation in the liver and skeletal muscle in high-fat- fed obese mice. These findings suggested that CA attenuates insulin resistance and promotes insulin sensitivity by enhancing mitochondrial function.

The variation of serum glucose, hepatic glycogen content and expression of glucose metabolism-related genes in hybrid grouper (female Epinephelus fuscoguttatus × male Epinephelus lanceolatus) in response to intraperitoneal insulin infusion

The present study was conducted to investigate the effects of insulin on serum glucose, hepatic glycogen content and expression of glucose metabolism-related genes in hybrid grouper. Triplicate groups of five fish were sampled at the 0, 1, 3, 6, 12, 24 or 48-h time point post-bovine insulin (5 μg 100/g fish body mass) injection. A significant decrease of serum glucose content was observed along with the depletion of hepatic glycogen content at the 12-h time point following insulin injection. Hepatic gene expression analysis revealed that the infusion of insulin significantly increased the expression of glucose transporters (GLUTs), GLUT1b and GLUT2. The transcription of gluconeogenesis-related genes, fructose-1,6-bisphosphatase 1a and glucose-6-phosphatase a catalytic subunit tandem duplicate 2, was significantly decreased at the 12-h time point, while the expression of glycolysis-related genes, phosphofructokinase liver b and pyruvate kinase L/R, was significantly up-regulated at the 24-h time point post-insulin injection. Meanwhile, the expression of glucokinase significantly increased immediately following insulin administration. The expression of glycogen synthase liver type significantly decreased at the 12-h time point, while the expression of glycogen phosphorylase liver type was significantly elevated at the 24-h time point following insulin injection. These results suggested that insulin could affect glucose metabolism through regulating gluconeogenesis, glycolysis and glycogen metabolism at the transcriptional level.

Effects of Apelin-13 on expression levels of glucose and lipid metabolism-related genes in the liver and skeletal muscle of diabetic rats

Objective To investigate the effects of exogenous Apelin-13 on the expression of glucose and fatty acid metabolism-related genes in the liver and skeletal muscle of diabetic rats. Methods Forty male Wister rats were randomly divided into a control group (n=8) and an experimental group (n=32). In the experimental group, a rat model of type 2 diabetes mellitus was established by a high-glucose and high-fat diet and intraperitoneal injection of streptozotocin (STZ). The diabetic rats were randomized into a diabetic model group and an Apelin-13 treatment group with 14 rats in each group.Rats in the Apelin-13 treatment group were intraperitoneally injected with 0.1 μmol·kg·d-1 Apelin-13 for 10 weeks, while the control group and the diabetic model group were injected with an equal volume of 0.9% NaCl solution for 10 weeks.At the end of the 10 week treatment, fasting blood glucose values in each group were measured.Levels of mRNA expression of glucose-6-phosphate (G-6-P), phosphoenolpyruvate carboxykinase (PEPCK), peroxisome proliferator-activated receptor alpha (PPAR-α), acy1-CoA synthetase long-chain family member1 (ACSL1), and carnitine palmitoyltransferase1 (CPT1) in the liver and levels of mRNA expression of PPAR-α and glucose transporter type 4 (GLUT4) in skeletal muscle were detected by real-time fluorescence quantitative polymerase chain reaction (PCR). Results Levels of mRNA expression of liver PPAR-α, liver ACSL1, liver CPT1, and GLUT4 in skeletal muscle were lower in the diabetic model group (0.309±0.073, 0.508±0.056, 0.389±0.118 and 0.289±0.066, respectively) than in the control group (0.971±0.028, 0.990±0.015, 0.987±0.015 and 0.994±0.009, respectively) (all P 0.05). Conclusions Apelin-13 increases the expression of the PPAR, ACSL1, and CPT1 genes in the liver and, to a certain extent, improves fatty acid oxidation metabolism in the liver in type 2 diabetic rats.It also increases the expression of the G-6-P and PEPCK genes, promotes gluconeogenesis in the liver, and may be related to the development of type 2 diabetes.In skeletal muscle, Apelin-13 increases GLUT4 gene expression, moderately improves skeletal muscle metabolism and may play a role in the regulation of oxidative stress. Key words: Diabetes mellitus; Carbohydrate metabolism; Lipid metabolism; Apelin-13

Programming of the glucose metabolism in rainbow trout juveniles after chronic hypoxia at hatching stage combined with a high dietary carbohydrate: Protein ratios intake at first-feeding

It is well known that change in environmental parameters experienced during early life can have profound effect on the metabolism of individuals later in life. The purpose of the present study was to evaluate the impact of a chronic hypoxic stimulus (15 days, 50% dissolved O2, 5.0 mg·L−1) applied at hatching (oxygen history) alone or combined with a 60% high carbohydrate (HC) dietary stimulus (8 days) applied at first-feeding (dietary history) on growth performance and glucose metabolism of juvenile trout. The effectiveness of the hypoxic and the HC dietary stimuli were verified by monitoring the modulation in mRNA levels of oxygen-sensitive and dietary carbohydrate-sensitive genes, respectively. At juvenile stage (28 weeks after first-feeding), neither dietary history nor oxygen history had long-term effect on growth performance. These juveniles were then subjected to a 5 days challenge test with a 30% carbohydrate diet. Our data showed that mRNA levels of some glucose transport-related genes in liver and muscle, and plasma triglycerides were down-regulated in fish which were exposed to hypoxia during early life. Regarding to the effect of dietary history, the mRNA level of muscular pfkmaa was observably increased in fish previously subjected to the HC dietary stimulus. In summary, the present study indicated that a chronic hypoxic stimulus applied at hatching alone or combined with a high carbohydrate stimulus at first-feeding can affect plasma triglycerides level and glucose metabolism-related genes in juvenile trout.

LncRNA-TP53TG1 Participated in the Stress Response Under Glucose Deprivation in Glioma.

Gliomas are the most common brain tumors of the center nervous system. And long non-coding RNAs (lncRNAs) are non-protein coding transcripts, which have been considered as one type of gene expression regulator for cancer development. In this study, we investigated the role of lncRNA-TP53TG1 in response to glucose deprivation in human gliomas. The expression levels of TP53TG1 in glioma tissues and cells were analyzed by qRT-PCR. In addition, the influence of TP53TG1 on glucose metabolism related genes at the mRNA level during both high and low glucose treatment was detected by qRT-PCR. MTT, clonogenicity assays, and flow cytometry were performed to detect the cell proliferation and cell apoptosis. Furthermore, the migration of glioma cells was examined by Transwell assays. The expression of TP53TG1 was significantly higher in human glioma tissues or cell lines compared with normal brain tissue or NHA. Moreover, TP53TG1 and some tumor glucose metabolism related genes, such as GRP78, LDHA, and IDH1 were up-regulated significantly in U87 and LN18 cells under glucose deprivation. In addition, knockdown of TP53TG1 decreased cell proliferation and migration and down-regulated GRP78 and IDH1 expression levels and up-regulated PKM2 levels in U87 cells under glucose deprivation. However, over-expression of TP53TG1 showed the opposite tendency. Moreover, the effects of TP53TG1 were more remarkable in low glucose than that in high glucose. Our data showed that TP53TG1 under glucose deprivation may promote cell proliferation and migration by influencing the expression of glucose metabolism related genes in glioma. J. Cell. Biochem. 118: 4897-4904, 2017. © 2017 Wiley Periodicals, Inc.

Neu-P11, a novel MT1/MT2 agonist, reverses diabetes by suppressing the hypothalamic-pituitary-adrenal axis in rats

Excessive glucocorticoid (GC) in type 2 diabetes mellitus (T2DM) reduces insulin sensitivity, impairs β-cell function, increases gluconeogenesis and glycogenolysis, impairs glucose uptake and metabolism, and reduces the insulinotropic effects of glucagon-like peptide 1. Melatonin, which serves as a physiological regulator of the hypothalamic-pituitary-adrenal (HPA) axis, has been suggested to have anti-diabetic effects. The objective of the present study was to investigate the effect of the MT1/MT2 melatonin agonist Neu-P11 on glucose and lipid metabolism in T2DM rats induced by a high fat diet combined with low doses of streptozotocin. T2DM rats were intragastrically administered melatonin (20mg/kg), Neu-P11 (20, 10, 5mg/kg), or a vehicle for 4 weeks. The results showed that the increased food intake, water consumption, hyperglycemia, glucose intolerance, and insulin resistance in T2DM rats were all improved by Neu-P11 treatment. Neu-P11 increased GC receptor expression and suppressed 11β-hydroxysteroid dehydrogenase 1 activity in the hippocampus by enhancing GC sensitivity and HPA feedback, thus decreasing the high GC levels. Transcript levels of the glucose metabolism-related genes peroxisome proliferator-activated receptor-γ, glucose transporter type-4, and adiponectin in adipose tissue were significantly increased after Neu-P11 treatment, while leptin mRNA was significantly decreased. Furthermore, MT1 and MT2 protein levels were enhanced by Neu-P11. These data suggest that normalization of the hyperactivated HPA axis by melatonin and Neu-P11 in T2DM regulates metabolic profiles and insulin sensitivity, which may attenuate insulin resistance and glucose homeostasis. Because Neu-P11 has superior pharmacokinetics and a longer half-life than melatonin, it might be beneficial in treating obesity and T2DM.

Abstract 4631: Enhanced glycolysis promotes function of tumor associated macrophages in mouse breast cancer model

Abstract Tumor associated macrophages(TAMs) represent a major part of immune cells in tumor microenvironment(TME) and play crucial roles in promoting tumor progression by secreting cytokines or enzymes that could remodel TME or enhance envision or migration capabilities of tumor cells. Given their indispensable effect on tumor, the mechanisms underlying TAMs’ tumor-promoting phenotype and function remain unclear. Glucose metabolism in tumor cells has been intensively studied; however, the status of glucose metabolism of TAMs is still unclear. In this study, we aim to identify glucose metabolism status in TAMs, and explore how glucose metabolism regulates phenotype and function of TAMs. In the begining, we isolated TAMs from 4T1 mouse breast tumor, spleen macrophages from normal mouse as a control, and performed RNA sequencing to analyze the expression pattern in glucose metabolism related genes. The results from transcriptomics showed that TAM shown up regulation of glycolysis genes pattern. Then we analyzed and found that HK’s activity was increased while IDH’s activity was decreased in mouse breast cancer moel. Furthermore, In vitro, we found that up regulation of impotent glycolysis genes including HK2, PFK-L and LDHA in mouse peritoneal macrophages (CMPM) and mouse bone marrow derived macrophages (CMBMDM) conditionally cultured with 4T1 supernatants. Glucose consumption or production of lactate and ATP were also increased in CMPM or CMBMDM. Then we monitored lactate producing rate with seahorse energy metabolism detector, and found that either CMPM or CMBMDM produced lactate faster than that of control. Moreover, inhibition of LDHA activity by oxamate ( inhibitor) also decreased glucose consumption and lactate production. Importantly, the expression of Arg1 and CD206, positively correlated with glycolysis and function of TAMs. Finally, we search the underneath mechanism and found PI3K/AKT pathway was activated in CMPM or CMBMDM. In detail it was found that p-p85 and p-AKT was upregulated at 8 hour after 4T1 supernatants stimulation. Inhibition of PI3K/AKT pathway by LY294002 (PI3K inhibitor), notably inhibited the expression of glycolysis genes and markers of TAMs, which indicated that PI3K/AKT pathway maybe involved in glycolysis of TAMs. Together, we identified that TAMs adopted glycolysis as a major way to consume glucose and glycolysis was directly contributed to the phenotype and function of TAMs, which was regulated by PI3K/AKT signaling pathway. Citation Format: Yan Liu, Wei Zhou, Wei Wang, Lipeng Bai, Huiwen He, Jian Guo, Yunping Luo. Enhanced glycolysis promotes function of tumor associated macrophages in mouse breast cancer model [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4631. doi:10.1158/1538-7445.AM2017-4631

Sake lees extract improves hepatic lipid accumulation in high fat diet-fed mice

BackgroundNonalcoholic fatty liver disease (NAFLD) is increasing worldwide as one of the leading causes of chronic liver disease. Sake lees (SL) are secondary products of sake manufacturing and are considered to have beneficial effects on human health. To investigate these effects, we used high fat diet (HFD)-fed mice treated with or without the SL extract.MethodMice were the HFD ad libitum for 8 weeks and were administered 500 μL of distilled water with or without the SL extract (350 mg/mL) by a feeding needle daily for the last 4 weeks. Food intake, body weight, and liver weight were measured. Triacylglycerol content and the mRNA and protein expression levels of various lipid and glucose metabolism-related genes were determined in liver tissues. The levels of triglyceride, free fatty acids, glucose, insulin, and liver cell damage markers were determined in serum. Fatty acid-induced lipid accumulation in HepG2 cells was assessed in the presence or absence of the SL extract.ResultsMice fed a HFD and treated with the SL extract demonstrated a significant reduction in hepatic lipid accumulation and mRNA and protein levels of peroxidome proliferator-activated receptor γ (PPARγ), PPARα, CD36, and phosphoenolpyruvate carboxykinase 1 in the liver, while the SL extract did not affect body weight and food intake. Moreover, insulin resistance and hepatic inflammation in HFD-fed mice improved after administration of the SL extract. In HepG2 cells, the SL extract suppressed fatty acid-induced intracellular lipid accumulation.ConclusionsThese findings suggest that treatment with the SL extract could potentially reduce the risk of NAFLD development, and that the SL extract may be clinically useful for the treatment of NAFLD.

Role of glucose metabolism related gene GLUT1 in the occurrence and prognosis of colorectal cancer.

Colorectal cancer (CRC) ranks the third most commonly diagnosed cancer in males and the second in females worldwide. However, the functional and causal SNPs for CRC remain to be mined. Glucose transporter 1 (GLUT1), a pivotal rate-limiting element in the transport of glucose in malignancy cells, has been identified to be associated with many cancers. Here, we aim to explore the role of GLUT1 in the occurrence and prognosis of colorectal cancer in a Chinese population. We found that GLUT1 expression levels in CRC tumor tissues were significantly higher than those in the corresponding adjacent normal tissues, and Cox multivariate analysis demonstrated that the GLUT1 expression was an independent prognostic factor for CRC (HR = 2.11, 95% CI = 1.33–3.34, P=0.001). For a functional polymorphism of GLUT1 (rs710218), we found that individuals with TT genotype (OR = 1.68, 95% CI = 1.02-2.75, P = 0.041) or AT genotype (OR = 1.47, 95% CI = 1.09-1.99, P = 0.012) of rs710218 had a significantly increased risk of CRC compared to those with AA homozygote. These findings strongly suggest that glucose metabolism related gene GLUT1, and its functional SNP, rs710218 might contribute to CRC susceptibility and prognosis, and the exact biological mechanism awaits further research.

Exposure to an acute hypoxic stimulus during early life affects the expression of glucose metabolism-related genes at first-feeding in trout

Rainbow trout (Oncorhynchus mykiss) is considered a “glucose-intolerant” species. With the aim of programming trout to improve their metabolic use of dietary carbohydrates, we hypothesised that a hypoxic stimulus applied during embryogenesis could later affect glucose metabolism at the first-feeding stage. An acute hypoxic stimulus (2.5 or 5.0 mg·L−1 O2) was applied for 24 h to non-hatched embryos or early hatched alevins followed by a challenge test with a high carbohydrate diet at first-feeding. The effectiveness of the early hypoxic stimulus was confirmed by the induction of oxygen-sensitive markers such as egln3. At first-feeding, trout previously subjected to the 2.5 mg·L−1 O2 hypoxia displayed a strong induction of glycolytic and glucose transport genes, whereas these glucose metabolism-related genes were affected much less in trout subjected to the less severe (5.0 mg·L−1 O2) hypoxia. Our results demonstrate that an acute hypoxic stimulus during early development can affect glucose metabolism in trout at first-feeding.

Royal jelly may improve the metabolism of glucose and redox state of ovine oocytes matured in vitro and embryonic development following in vitro fertilization

The aim of this study was to investigate the effect of different concentrations of royal jelly (RJ) on in vitro maturation (IVM), fertilization, cleavage, blastocyst rates, glutathione (GSH) content in ovine oocyte, mRNA abundance of antioxidant enzymes in both oocyte and cumulus, and glucose metabolism-related genes in cumulus cells. In vitro maturation of oocyte was performed in the presence of control (RJ0), 2.5 (RJ2.5), 5 (RJ5), and 10 (RJ10) mg/mL of RJ. Nuclear status, intracellular GSH content in oocytes, and mRNA abundance of selected genes were evaluated following 24 hours of IVM. Following the IVM, fertilization and embryo culture were carried out in all the groups and embryonic development was examined. The addition of 10-mg/mL RJ to maturation media not only yielded a higher number of oocytes at MII stage but also showed an increased level of intracellular GSH content than did RJ2.5 and control groups. Fertilization, cleavage, and blastocyst rate were higher in the RJ10 treatment group in comparison to the control one. In cumulus cells, the expression of PFKM, PFKL, and G6PDH were increased following the addition of RJ to the maturation media. Supplementation of 10-mg/mL RJ to IVM medium increased the GPx mRNA abundance in both oocyte and cumulus cells and SOD expression in the cumulus cells. The CAT mRNA abundance was not influenced by the addition of RJ to the maturation media in either oocyte or cumulus cells. It seems that the improvement of oocyte maturation and its subsequent development in RJ10 group may be associated with amelioration of redox status in the oocytes and activation of glucose metabolic pathways in their surrounding cumulus cells.

Developmental changes in hepatic glucose metabolism in a newborn piglet model: A comparative analysis for suckling period and early weaning period

The liver glucose metabolism, supplying sufficient energy for glucose-dependent tissues, is important in suckling or weaned animals, although there are few studies with piglet model. To better understand the development of glucose metabolism in the piglets during suckling period and early weaning period, we determined the hepatic glycogen content, and investigated the relative protein expression of key enzymes of glucogenesis (GNG) and mRNA levels of some glucose metabolism-related genes. During suckling period, the protein level of G6Pase in the liver of suckling piglets progressively declined with day of age compared with that of newborn piglets (at 1 day of age), whereas the PEPCK level stabilized until day 21 of age, indicating that hepatic GNG capacity gradually weakened in suckling piglets. The synthesis of hepatic glycogen, which was consistent with the fluctuation of glycolytic key genes PFKL and PKLR that gradually decreased after birth and was more or less steady during latter suckling period, although both the mRNA levels of GCK and key glucose transporter GLUT2 presented uptrend in suckling piglets. However, early weaning significantly suppressed the hepatic GNG in the weaned piglets, especially at d 3–5 of weaning period, then gradually recovered at d 7 of weaning period. Meanwhile, PFKL, PKLR and GLUT2 showed the similar trend during weaning period. On the contrast, the hepatic glycogen reached the maximum value when the G6Pase and PEPCK protein expression were at the lowest level, although the GCK level maintained increasing through 7 days of weaning period. Altogether, our study provides evidence that hepatic GNG and glycolysis in newborn piglets were more active than other days during suckling period, and early weaning could significantly suppressed glucose metabolism in liver, but this inhibition would progressively recover at day 7 after weaning.

Glucose metabolism ontogenesis in rainbow trout (Oncorhynchus mykiss) in the light of the recently sequenced genome: new tools for intermediary metabolism programming.

The rainbow trout (Oncorhynchus mykiss), a carnivorous fish species, displays a 'glucose-intolerant' phenotype when fed a high-carbohydrate diet. The importance of carbohydrate metabolism during embryogenesis and the timing of establishing this later phenotype are currently unclear. In addition, the mechanisms underlying the poor ability of carnivorous fish to use dietary carbohydrates as a major energy substrate are not well understood. It has recently been shown in trout that duplicated genes involved in glucose metabolism may participate in establishing the glucose-intolerant phenotype. The aim of this study was therefore to provide new understanding of glucose metabolism during ontogenesis and nutritional transition, taking into consideration the complexity of the trout genome. Trout were sampled at several stages of development from fertilization to hatching, and alevins were then fed a non-carbohydrate or a high-carbohydrate diet during first feeding. mRNA levels of all glucose metabolism-related genes increased in embryos during the setting up of the primitive liver. After the first meal, genes rapidly displayed expression patterns equivalent to those observed in the livers of juveniles. g6pcb2.a (a glucose 6-phosphatase-encoding gene) was up-regulated in alevins fed a high-carbohydrate diet, mimicking the expression pattern of gck genes. The g6pcb2.a gene may contribute to the non-inhibition of the last step of gluconeogenesis and thus to establishing the glucose-intolerant phenotype in trout fed a high-carbohydrate diet as early as first feeding. This information is crucial for nutritional programming investigations as it suggests that first feeding would be too late to programme glucose metabolism in the long term.

Twist promotes reprogramming of glucose metabolism in breast cancer cells through PI3K/AKT and p53 signaling pathways.

Twist, a key regulator of epithelial-mesenchymal transition (EMT), plays an important role in the development of a tumorigenic phenotype. Energy metabolism reprogramming (EMR), a newly discovered hallmark of cancer cells, potentiates cancer cell proliferation, survival, and invasion. Currently little is known about the effects of Twist on tumor EMR. In this study, we found that glucose consumption and lactate production were increased and mitochondrial mass was decreased in Twist-overexpressing MCF10A mammary epithelial cells compared with vector-expressing MCF10A cells. Moreover, these Twist-induced phenotypic changes were augmented by hypoxia. The expression of some glucose metabolism-related genes such as PKM2, LDHA, and G6PD was also found to be upregulated. Mechanistically, activated β1-integrin/FAK/PI3K/AKT/mTOR and suppressed P53 signaling were responsible for the observed EMR. Knockdown of Twist reversed the effects of Twist on EMR in Twist-overexpressing MCF10A cells and Twist-positive breast cancer cells. Furthermore, blockage of the β1-integrin/FAK/PI3K/AKT/mTOR pathway by siRNA or specific chemical inhibitors, or rescue of p53 activation can partially reverse the switch of glucose metabolism and inhibit the migration of Twist-overexpressing MCF10A cells and Twist-positive breast cancer cells. Thus, our data suggest that Twist promotes reprogramming of glucose metabolism in MCF10A-Twist cells and Twist-positive breast cancer cells via activation of the β1-integrin/FAK/PI3K/AKT/mTOR pathway and inhibition of the p53 pathway. Our study provides new insight into EMR.