scholarly journals Regulation of lactate production and glucose transport as well as of glucose transporter 1 and lactate dehydrogenase A mRNA levels by basic fibroblast growth factor in rat Sertoli cells

2002 ◽  
Vol 173 (2) ◽  
pp. 335-343 ◽  
Author(s):  
MF Riera ◽  
SB Meroni ◽  
HF Schteingart ◽  
EH Pellizzari ◽  
SB Cigorraga
Keyword(s):  
Growth Factor ◽  
Glucose Transport ◽  
Glucose Transporter ◽  
Lactate Production ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Short Term ◽  
Glucose Transporter 1 ◽  
Ldh Activity

By using cultured rat Sertoli cells as a model, both the action of basic fibroblast growth factor (bFGF) on lactate production and the site of this action were studied. bFGF stimulated Sertoli cell lactate production in a dose-dependent manner (basal: 7.3+/-0.5; 0.1 ng/ml bFGF: 7.5+/-0.5; 1 ng/ml bFGF: 7.5+/-0.6; 10 ng/ml bFGF: 10.3+/-1.0; 30 ng/ml bFGF: 15.2+/-1.5; 50 ng/ml bFGF: 15.4+/-1.6 microg/microg DNA). Two major sites for the action of this growth factor were identified. First, bFGF was shown to exert short- and long-term stimulatory effects on glucose transport (basal: 1170+/-102; 30 ng/ml bFGF for 120 min: 1718+/-152 and basal: 718+/-64; 30 ng/ml bFGF for 48 h: 1069+/-69 d.p.m./microg DNA respectively). Short-term bFGF stimulation of glucose transport was not inhibited by the protein synthesis inhibitor cycloheximide. These results indicate that short-term bFGF stimulation of glucose uptake does not involve an increase in the number of glucose transporters. On the other hand, stimulation with bFGF for periods of time longer than 12 h increased glucose transporter 1 (GLUT1) mRNA levels. These increased mRNA levels were probably ultimately responsible for the increments in glucose uptake that are observed in long-term treated cultures. Secondly, bFGF increased lactate dehydrogenase (LDH) activity (basal: 31.0+/-1.4; 30 ng/ml bFGF: 45.7+/- 2.4 mIU/microg DNA). The principal subunit component of those LDH isozymes that favors the transformation of pyruvate to lactate is subunit A. bFGF increased LDH A mRNA levels in a dose- and time-dependent manner. In summary, the results presented herein show that glucose transport, LDH activity and GLUT1 and LDH A mRNA levels are regulated by bFGF to achieve an increase in lactate production. These observed regulatory actions provide unequivocal evidence of the participation of bFGF in Sertoli cell lactate production which may be related to normal germ cell development.

scholarly journals The Fast Lane of Hypoxic Adaptation: Glucose Transport Is Modulated via A HIF-Hydroxylase-AMPK-Axis in Jejunum Epithelium

2019 ◽  
Vol 20 (20) ◽  
pp. 4993 ◽  
Author(s):  
Dengler ◽  
Gäbel
Keyword(s):  
Glucose Transport ◽  
Glucose Transporter ◽  
Ussing Chamber ◽  
Transepithelial Transport ◽  
Adaptation To Hypoxia ◽  
Regulation Mechanism ◽  
Short Term ◽  
Glucose Transporter 1 ◽  
Functional Changes ◽  
Short Term Adaptation

The intestinal epithelium is able to adapt to varying blood flow and, thus, oxygen availability. Still, the adaptation fails under pathologic situations. A better understanding of the mechanisms underlying the epithelial adaptation to hypoxia could help to improve the therapeutic approach. We hypothesized that the short-term adaptation to hypoxia is mediated via AMP-activated protein kinase (AMPK) and that it is coupled to the long-term adaptation by a common regulation mechanism, the HIF-hydroxylase enzymes. Further, we hypothesized the transepithelial transport of glucose to be part of this short-term adaptation. We conducted Ussing chamber studies using isolated lagomorph jejunum epithelium and cell culture experiments with CaCo-2 cells. The epithelia and cells were incubated under 100% and 21% O2, respectively, with the panhydroxylase inhibitor dimethyloxalylglycine (DMOG) or under 1% O2. We showed an activation of AMPK under hypoxia and after incubation with DMOG by Western blot. This could be related to functional effects like an impairment of Na+-coupled glucose transport. Inhibitor studies revealed a recruitment of glucose transporter 1 under hypoxia, but not after incubation with DMOG. Summing up, we showed an influence of hydroxylase enzymes on AMPK activity and similarities between hypoxia and the effects of hydroxylase inhibition on functional changes.

scholarly journals LPA stimulates intestinal DRA gene transcription via LPA2 receptor, PI3K/AKT, and c-Fos-dependent pathway

2012 ◽  
Vol 302 (6) ◽  
pp. G618-G627 ◽  
Author(s):  
Amika Singla ◽  
Anoop Kumar ◽  
Shubha Priyamvada ◽  
Maliha Tahniyath ◽  
Seema Saksena ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Gene Transcription ◽  
Promoter Activity ◽  
Intestinal Epithelial Cells ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Intestinal Epithelial ◽  
Short Term ◽  
Exchange Activity

DRA (downregulated in adenoma) or SLC26A3 is the major apical anion exchanger mediating Cl− absorption in intestinal epithelial cells. Disturbances in DRA function and expression have been implicated in diarrheal conditions such as congenital chloride diarrhea and inflammatory bowel diseases. Previous studies have shown that DRA is subject to regulation by short-term and transcriptional mechanisms. In this regard, we have recently shown that short-term treatment by lysophosphatidic acid (LPA), an important bioactive phospholipid, stimulates Cl−/HCO3−(OH−) exchange activity via an increase in DRA surface levels in human intestinal epithelial cells. However, the long-term effects of LPA on DRA at the level of gene transcription have not been examined. The present studies were aimed at investigating the effects of LPA on DRA function and expression as well as elucidating the mechanisms underlying its transcriptional regulation. Long-term LPA treatment increased the Cl−/HCO3− exchange activity in Caco-2 cells. LPA treatment (50–100 μM) of Caco-2 cells significantly stimulated DRA mRNA levels and DRA promoter activity (−1183/+114). This increase in DRA promoter activity involved the LPA2 receptor and phosphatidylinositol 3-kinase (PI3K)/AKT pathways. Progressive deletions from −1183/+114 to −790/+114 abrogated the stimulatory effects of LPA, indicating that the −1183/−790 promoter region harbors LPA response elements. Utilizing EMSA and mutational studies, our results showed that LPA induced the DRA promoter activity in a c-Fos-dependent manner. LPA also increased the protein expression of c-Fos and c-Jun in Caco-2 cells. Furthermore, overexpression of c-Fos but not c-Jun enhanced the DRA promoter activity. This increase in DRA transcription in response to LPA indicates that LPA may act as an antidiarrheal agent and could be exploited for the treatment of diarrhea associated with inflammatory or infectious diseases of the gut.

scholarly journals Insulin and insulin-like growth factor 1 antagonize the stimulation of ob gene expression by dexamethasone in cultured rat adipose tissue

1997 ◽  
Vol 324 (2) ◽  
pp. 605-610 ◽  
Author(s):  
Bénédicte A. REUL ◽  
Lumbe N. ONGEMBA ◽  
Anne-Marie Marie ◽  
Jean-Claude HENQUIN ◽  
Sonia M. BRICHARD
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Growth Factor ◽  
Fatty Acid Synthase ◽  
Glucose Transporter ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Insulin Like Growth Factor ◽  
Ob Gene ◽  
Rat Adipose Tissue

The ob gene, specifically expressed in fat cells, encodes leptin, a hormone that induces satiety and increases energy expenditure. In this study, we investigated the interactions between glucocorticoids and insulin on ob gene expression in cultured explants of rat adipose tissue. Only low levels of ob mRNA were detected when adipose tissue from fasted rats was cultured for 12–24 h in minimal essential medium. However, the addition of dexamethasone to the medium increased ob gene expression in a concentration-dependent manner (EC50 10 nM). With 1 μM dexamethasone, ob mRNA levels were similar to those in fresh fat pads from fed rats, reaching a maximum after 12 h. The effect of dexamethasone was blocked by actinomycin D, which indicates an action on transcription. This effect was increased when a minimum amount of fuel (glucose or a mixture of lactate and pyruvate) was supplied in the medium. Unlike dexamethasone, insulin, even when combined with high glucose concentrations, did not induce ob expression, although it strongly increased the accumulation of mRNA species for fatty acid synthase (FAS), the insulin-sensitive glucose transporter GLUT4 and the γ isoform of peroxisome proliferator-activated receptor (PPARγ). Unexpectedly, insulin dose-dependently inhibited dexamethasone-induced ob mRNA accumulation. This effect was observed at low concentrations of insulin (IC50 1 nM) and was delayed in onset, beginning after 6–9 h of culture. It was mimicked by insulin-like growth factor 1 (IGF-1) (100 nM). The inhibition by insulin was only detectable when fuels were present and/or when a critical level of ob expression was reached. As this inhibitory effect was reversed by cycloheximide, this suggests that it required ongoing protein synthesis. In conclusion, unlike dexamethasone, insulin had no direct stimulatory effect on ob gene expression. On the other hand, insulin (and IGF-1) even inhibited the dexamethasone-induced accumulation of ob mRNA. The underlying mechanism involved ongoing synthesis of an inhibitory protein by insulin, which is in keeping with its delayed effect. Moreover, the expression of genes for FAS, GLUT4 and PPARγ may be inversely related to that of ob.

scholarly journals Unique mechanism of GLUT3 glucose transporter regulation by prolonged energy demand: increased protein half-life

1998 ◽  
Vol 333 (3) ◽  
pp. 713-718 ◽  
Author(s):  
Zayna A. KHAYAT ◽  
Anthony L. McCALL ◽  
Amira KLIP
Keyword(s):  
Glucose Uptake ◽  
Protein Content ◽  
Glucose Transport ◽  
Half Life ◽  
Glucose Transporter ◽  
Muscle Cells ◽  
Mrna Levels ◽  
Glut1 Protein ◽  
L6 Muscle Cells

L6 muscle cells survive long-term (18 h) disruption of oxidative phosphorylation by the mitochondrial uncoupler 2,4-dinitrophenol (DNP) because, in response to this metabolic stress, they increase their rate of glucose transport. This response is associated with an elevation of the protein content of glucose transporter isoforms GLUT3 and GLUT1, but not GLUT4. Previously we have reported that the rise in GLUT1 expression is likely to be a result of de novo biosynthesis of the transporter, since the uncoupler increases GLUT1 mRNA levels. Unlike GLUT1, very little is known about how interfering with mitochondrial ATP production regulates GLUT3 protein expression. Here we examine the mechanisms employed by DNP to increase GLUT3 protein content and glucose uptake in L6 muscle cells. We report that, in contrast with GLUT1, continuous exposure to DNP had no effect on GLUT3 mRNA levels. DNP-stimulated glucose transport was unaffected by the protein-synthesis inhibitor cycloheximide. The increase in GLUT3 protein mediated by DNP was also insensitive to cycloheximide, paralleling the response of glucose uptake, whereas the rise in GLUT1 protein levels was blocked by the inhibitor. The GLUT3 glucose transporter may therefore provide the majority of the glucose transport stimulation by DNP, despite elevated levels of GLUT1 protein. The half-lives of GLUT3 and GLUT1 proteins in L6 myotubes were determined to be about 15 h and 6 h respectively. DNP prolonged the half-life of both proteins. After 24 h of DNP treatment, 88% of GLUT3 protein and 57% of GLUT1 protein had not turned over, compared with 25% in untreated cells. We conclude that the long-term stimulation of glucose transport by DNP arises from an elevation of GLUT3 protein content associated with an increase in GLUT3 protein half-life. These findings suggest that disruption of the oxidative chain of L6 muscle cells leads to an adaptive response of glucose transport that is distinct from the insulin response, involving specific glucose transporter isoforms that are regulated by different mechanisms.

scholarly journals Cancer Cells’ Metabolism Dynamics in Renal Cell Carcinoma Patients’ Outcome: Influence of GLUT-1-Related hsa-miR-144 and hsa-miR-186

Cancers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1733
Author(s):  
Mariana Morais ◽  
Francisca Dias ◽  
Inês Nogueira ◽  
Anabela Leão ◽  
Nuno Gonçalves ◽  
...  
Keyword(s):  
Renal Cell Carcinoma ◽  
Cell Carcinoma ◽  
Cancer Cells ◽  
Renal Cell ◽  
Glucose Transporter ◽  
Lactate Production ◽  
High Risk Group ◽  
Mrna Levels ◽  
Glucose Transporter 1 ◽  
Glut 1

The cancer cells’ metabolism is altered due to deregulation of key proteins, including glucose transporter 1 (GLUT-1), whose mRNA levels are influenced by microRNAs (miRNAs). Renal cell carcinoma (RCC) is the most common and lethal neoplasia in the adult kidney, mostly due to the lack of accurate diagnosis and follow-up biomarkers. Being a metabolic associated cancer, this study aimed to understand the hsa-miR-144-5p and hsa-miR-186-3p’s potential as biomarkers of clear cell RCC (ccRCC), establishing their role in its glycolysis status. Using three ccRCC lines, the intra- and extracellular levels of both miRNAs, GLUT-1’s mRNA expression and protein levels were assessed. Glucose consumption and lactate production were evaluated as glycolysis markers. A decrease of intracellular levels of these miRNAs and increase of their excretion was observed, associated with an increase of GLUT-1’s levels and glycolysis’ markers. Through a liquid biopsy approach, we found that RCC patients present higher plasmatic levels of hsa-miR-186-3p than healthy individuals. The Hsa-miR144-5p’s higher levels were associated with early clinical stages. When patients were stratified according to miRNAs plasmatic levels, low plasmatic levels of hsa-miR-144-5p and high plasmatic levels of hsa-miR-186-3p (high-risk group) showed the worst overall survival. Thus, circulating levels of these miRNAs may be potential biomarkers of ccRCC prognosis.

scholarly journals Dysregulated GLUT1 May Be Involved in the Pathogenesis of Preeclampsia by Impairing Decidualization

2021 ◽  
Author(s):  
Man Yang ◽  
Hua Li ◽  
Miaomiao Rong ◽  
Hongya Zhang ◽  
Linlin Hou ◽  
...  
Keyword(s):  
Glucose Uptake ◽  
Glucose Transporter ◽  
Aerobic Glycolysis ◽  
Lactate Production ◽  
Target Prediction ◽  
Mrna Levels ◽  
Endometrial Stromal Cells ◽  
Glucose Transporter 1

Abstract Background: Preeclampsia (PE), a hypertensive complication in pregnancy, is a major contributor to maternal and fetal morbidity and mortality. Thus far, the molecular mechanism underlying PE has not been investigated thoroughly. Glucose transporter 1 (GLUT1) is a central rate-limiting pump for glucose uptake and subsequent utilization. Our previous RNA-seq results demonstrated it was significantly downregulated in deciduas from severe PE patients. Therefore, we aimed to explore the role of GLUT1 in the occurrence of PE.Methods: In this study, GLUT1 levels were evaluated by quantitative PCR, Western blotting and immunohistochemical staining in severe preeclamptic deciduas. The levels of GLUT1 during decidualization were also studied in human endometrial stromal cells (hESCs). Moreover, the role of GLUT1 during decidualization was studied by GLUT1-siRNA treatment. Furthermore, we explored the regulatory role of miRNA in GLUT1 expression.Results: The expression of GLUT1 was significantly downregulated in the deciduas from severe PE patients. Additionally, the level of GLUT1 was substantially induced in hESCs during in vitro decidualization. Moreover, GLUT1 knockdown significantly reduced the mRNA levels of decidualization markers (IGFBP1 and PRL) and aerobic glycolysis-related genes (LDHA and MCT4), and decreased glucose uptake and lactate production. Furthermore, the levels of apoptotic genes P53, P21 and BAX increased whereas the levels of BCL2 decreased after GLUT1 knockdown. Target prediction results and luciferase analysis showed GLUT1 is one of the targets of miR-140-5p, which is partly responsible for the impaired GLUT1 level. Conclusion: These results demonstrate that GLUT1 exerts pivotal role in human decidualization by participating in glycolysis, and its deficiency may trigger aberrant glycolysis and thus leads to destructive decidualization, which may be a pathogenetic mechanism of PE. These data suggest GLUT1 might be a promising target for PE therapy.

scholarly journals Matrix Stiffness Modulates Metabolic Interaction between Human Stromal and Breast Cancer Cells to Stimulate Epithelial Motility

Metabolites ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 432
Author(s):  
Iván Ponce ◽  
Nelson Garrido ◽  
Nicolás Tobar ◽  
Francisco Melo ◽  
Patricio C. Smith ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Stromal Cells ◽  
Glucose Transporter ◽  
Lactate Production ◽  
Resonance Energy ◽  
Metabolic Reprogramming ◽  
Dependent Manner ◽  
Functional Link

Breast tumors belong to the type of desmoplastic lesion in which a stiffer tissue structure is a determinant of breast cancer progression and constitutes a risk factor for breast cancer development. It has been proposed that cancer-associated stromal cells (responsible for this fibrotic phenomenon) are able to metabolize glucose via lactate production, which supports the catabolic metabolism of cancer cells. The aim of this work was to investigate the possible functional link between these two processes. To measure the effect of matrix rigidity on metabolic determinations, we used compliant elastic polyacrylamide gels as a substrate material, to which matrix molecules were covalently linked. We evaluated metabolite transport in stromal cells using two different FRET (Fluorescence Resonance Energy Transfer) nanosensors specific for glucose and lactate. Cell migration/invasion was evaluated using Transwell devices. We show that increased stiffness stimulates lactate production and glucose uptake by mammary fibroblasts. This response was correlated with the expression of stromal glucose transporter Glut1 and monocarboxylate transporters MCT4. Moreover, mammary stromal cells cultured on stiff matrices generated soluble factors that stimulated epithelial breast migration in a stiffness-dependent manner. Using a normal breast stromal cell line, we found that a stiffer extracellular matrix favors the acquisition mechanistical properties that promote metabolic reprograming and also constitute a stimulus for epithelial motility. This new knowledge will help us to better understand the complex relationship between fibrosis, metabolic reprogramming, and cancer malignancy.

scholarly journals Glucolipotoxicity and GLP-1 secretion

2021 ◽  
Vol 9 (1) ◽  
pp. e001905
Author(s):  
Jung-Hee Hong ◽  
Dae-Hee Kim ◽  
Moon-Kyu Lee
Keyword(s):  
Glucose Transporter ◽  
Cell Function ◽  
Nicotinamide Adenine Dinucleotide Phosphate ◽  
Mrna Levels ◽  
Dependent Manner ◽  
Gene Expressions ◽  
Simultaneous Treatment ◽  
L Cells ◽  
Triglyceride Accumulation

IntroductionThe concept of glucolipotoxicity refers to the combined, deleterious effects of elevated glucose and/or fatty acid levels.Research design and methodsTo investigate the effects of chronic glucolipotoxicity on glucagon-like peptide-1-(7-36) amide (GLP-1) secretion, we generated glucolipotoxic conditions in human NCI-H716 enteroendocrine cells using either 5 or 25 mM glucose with or without 500 µM palmitate for 72 hours. For in vivo study, we have established a chronic nutrient infusion model in the rat. Serial blood samples were collected for 2 hours after the consumption of a mixed meal to evaluate insulin sensitivity and β-cell function.ResultsChronic glucolipotoxic conditions decreased GLP-1 secretion and the expressions of pCREB, pGSK3β, β-catenin, and TCF7L2 in NCI-H716 cells. Glucolipotoxicity conditions reduced glucose transporter expression, glucose uptake, and nicotinamide-adenine dinucleotide phosphate (NADPH) levels in L-cells, and increased triglyceride accumulation. In contrast, PPARα and ATP levels were reduced, which correlated well with decreased levels of SUR1 and Kir6.2, cAMP contents and expressions of pCAMK2, EPAC and PKA. We also observed an increase in reactive oxygen species production, UCP2 expression and Complex I activity. Simultaneous treatment with insulin restored the GLP-1 secretion. Glucolipotoxic conditions decreased insulin secretion in a time-dependent manner in INS-1 cells, which was recovered with exendin-4 cotreatment. Glucose and SMOFlipid infusion for 6 hours decreased GLP-1 secretion and proglucagon mRNA levels as well as impaired the glucose tolerance, insulin and C-peptide secretion in rats.ConclusionThese results provide evidence for the first time that glucolipotoxicity could affect GLP-1 secretion through changes in glucose and lipid metabolism, gene expressions, and proglucagon biosynthesis and suggest the interrelationship between glucolipotoxicities of L-cells and β-cells which develops earlier than that of L-cells.

Spontaneous immortalisation of Schwann cells in culture: short-term cultured Schwann cells secrete growth inhibitory activity

Development ◽  
1991 ◽  
Vol 112 (1) ◽  
pp. 33-42
Author(s):  
P.A. Eccleston ◽  
R. Mirsky ◽  
K.R. Jessen
Keyword(s):  
Growth Factor ◽  
Schwann Cell ◽  
Dna Synthesis ◽  
Schwann Cells ◽  
Inhibitory Activity ◽  
Short Term ◽  
Growth Inhibitory ◽  
Growth Inhibitory Activity ◽  
Cultured Schwann Cells

In the developing peripheral nerve, Schwann cells proliferate rapidly and then become quiescent, an essential step in control of Schwann cell differentiation. Cell proliferation is controlled by growth factors that can exert positive or inhibitory influences on DNA synthesis. It has been well established that neonatal Schwann cells divide very slowly in culture when separated from neurons but here we show that when culture was continued for several months some cells began to proliferate rapidly and non-clonal lines of immortalised Schwann cells were established which could be passaged for over two years. These cells had a similar molecular phenotype to short-term cultured Schwann cells, except that they expressed intracellular and cell surface fibronectin. The difference in proliferation rates between short- and long-term cultured Schwann cells appeared to be due in part to the secretion by short-term cultured Schwann cells of growth inhibitory activity since DNA synthesis of long-term, immortalised Schwann cells was inhibited by conditioned medium from short-term cultures. This conditioned medium also inhibited DNA synthesis in short-term Schwann cells stimulated to divide by glial growth factor or elevation of intracellular cAMP. The growth inhibitory activity was not detected in the medium of long-term immortalised Schwann cells, epineurial fibroblasts, a Schwannoma (33B), astrocytes or a fibroblast-like cell-line (3T3) and it did not inhibit serum-induced DNA synthesis in epineurial fibroblasts, 33B cells or 3T3 cells. The activity was apparently distinct from transforming growth factor-beta, activin, IL6, epidermal growth factor, atrial natriuretic peptide and gamma-interferon and was heat and acid stable, resistant to collagenase and destroyed by trypsin treatment. We raise the possibility that loss of an inhibitory autocrine loop may contribute to the rapid proliferation of long-term cultured Schwann cells and that an autocrine growth inhibitor may have a role in the cessation of Schwann cell division that precedes differentiation in peripheral nerve development.

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