Glucose transporter 3 (GLUT3) promotes lactylation modifications by regulating lactate dehydrogenase A (LDHA) in gastric cancer.

OBJECTIVES: Glucose transporter 3 (GLUT3) plays a major role in glycolysis and glucose metabolism in cancer cells. We aimed to investigate the correlation between GLUT3 and histone lactylation modification in the occurrence and progression of gastric cancer. MATERIALS AND METHODS: We initially used single-cell sequencing data to determine the expression levels of GLUT3 and lactate dehydrogenase A (LDHA) in primary tumor, tumor-adjacent normal, and metastasis tumor tissues. Immunohistochemistry analysis was conducted to measure GLUT3, LDHA, and L-lactyl levels in gastric normal and cancer tissues. Transwell and scratch assays were performed to evaluate the metastatic and invasive capacity of gastric cancer cell lines. Western blotting was used to measure L-lactyl and histone lactylation levels in gastric cancer cell lines. RESULTS: Single-cell sequencing data showed that GLUT3 expression was significantly increased in primary tumor and metastasis tumor tissues. In addition, GLUT3 expression was positively correlated with that of LDHA expression and lactylation-related pathways. Western blotting and immunohistochemistry analyses revealed that GLUT3 was highly expressed in gastric cancer tissues and cell lines. GLUT3 knockdown in gastric cancer cell lines inhibited their metastatic and invasive capacity to various degrees. Additionally, the levels of LDHA, L-lactyl, H3K9, H3K18, and H3K56 significantly decreased after GLUT3 knockdown, indicating that GLUT3 affects lactylation in gastric cancer cells. Moreover, LDHA overexpression in a GLUT3 knockdown cell line reversed the levels of lactylation and EMT-related markers, and the EMT functional phenotype induced by GLUT3 knockdown. The in vivo results were consistent with the in vitro results. CONCLUSIONS: This study suggests the important role of histone lactylation in the occurrence and progression of gastric cancer, and GLUT3 may be a new diagnostic marker and therapeutic target for gastric cancer.

Peritoneal Expression of SGLT-2, GLUT1, and GLUT3 in Peritoneal Dialysis Patients.

INTRODUCTION: In peritoneal dialysis (PD) patients, the peritoneal membrane is affected by glucose-based solutions used as peritoneal dialysate fluids. This exposure leads to changes of the membrane which may eventually culminate in fibrosis and method failure. In vitro or animal studies demonstrated that glucose transporters are upregulated upon exposure to these solutions. Expression studies of glucose transporters in human peritoneum have not been reported yet. METHODS: Expression of SGLT-2, GLUT1, and GLUT3 in human peritoneal biopsies was analyzed by real-time polymerase chain reaction and Western blot analysis. The localization of these glucose transporters in the peritoneum was evaluated by immunohistochemistry using a Histo-Score. RESULTS: Peritoneal biopsies of patients (healthy controls, uremic, PD, and encapsulating peritoneal sclerosis [EPS]) were analyzed. We found evidence of SGLT-2, GLUT1, and GLUT3 expression in the peritoneal membrane. Protein expression of SGLT-2 increases with PD duration and is significantly enhanced in EPS patients. All transporters were predominantly, but not exclusively, located adjacent to the vessel walls of the peritoneal membrane. CONCLUSION: Our study showed that SGLT-2, GLUT1, and GLUT3 were regularly expressed in the human peritoneum. SGLT-2 was particularly upregulated in PD patients with EPS, suggesting that this upregulation may be associated with pathological changes in the peritoneal membrane in this syndrome. Since preclinical studies in mice show that SGLT-2 inhibitors or downregulation of SGLT-2 ameliorated pathological changes in the peritoneum, SGLT-2 inhibitors may be potentially promising agents for therapy in PD patients that could reduce glucose absorption and delay functional deterioration of the peritoneal membrane in the long term.

Altered glucose metabolism and its association with carbonic anhydrase 8 in Machado-Joseph Disease.

Machado-Joseph disease (MJD), also known as spinocerebellar ataxia type 3 (SCA3), is an autosomal dominant neurodegenerative disease. This disorder is caused by polyglutamine (polyQ)-containing mutant ataxin-3, which tends to misfold and aggregate in neuron cells. We previously demonstrated a protective function of carbonic anhydrase 8 (CA8) in MJD disease models and a decreased glycolytic activity associated with down-regulated CA8 in a human osteosarcoma (OS) cell model. Given that a reduction in body weight accompanied by gait and balance instability was observed in MJD patients and transgenic (Tg) mice, in this study, we aimed to examine whether metabolic defects are associated with MJD and whether CA8 expression is involved in metabolic dysfunction in MJD. Our data first showed that glucose uptake ability decreases in cells harboring mutant ataxin-3, but increases in cells overexpressing CA8. In addition, the expressions of glucose transporter 3 (GLUT3) and phosphofructokinase-1 (PFK1) were significantly decreased in the presence of mutant ataxin-3. Consistently, immunohistochemistry (IHC) showed that GLUT3 was less expressed in cerebella of aged MJD Tg mice, indicating that the dysfunction of GLUT3 may be associated with late-stage disease. On the other hand, transient down-regulation of CA8 revealed decreased expressions of GLUT3 and PFK1 in HEK293 cells harboring wild-type (WT) ataxin-3, but no further reduction of GLUT3 and PFK1 expressions were observed in HEK293 cells harboring mutant ataxin-3. Moreover, immunoprecipitation (IP) and immunofluorescence (IF) demonstrated that interactions exist between ataxin-3, CA8 and GLUT3 in MJD cellular and Tg models. These lines of evidence suggest that CA8 plays an important role in glucose metabolism and has different impacts on cells with or without mutant ataxin-3. Interestingly, the decreased relative abundance of Firmicutes/Bacteroidetes (F/B) ratio in the feces of aged MJD Tg mice coincided with weight loss and metabolic dysfunction in MJD. Taken together, our results are the first to demonstrate the effects of CA8 on glucose metabolism and its involvement in the metabolic defects in MJD disease. Further investigations will be required to clarify the underlying mechanisms for the metabolic defects associated with MJD.

Placental glucose transporter 1 and 3 gene expression in Monochorionic twin pregnancies with selective fetal growth restriction.

BACKGROUND: In monochorionic twin (MC) gestations with selective fetal growth restriction (FGR), the discordant fetal growth usually is due to unequal placental sharing. Glucose, which is essential for oxidative metabolism in the growing placenta and fetus, is transferred from maternal blood by facilitated carrier-mediated diffusion via glucose transporters (GLUTs). How the GLUTs expression varies in the two placenta territories manifests discordant perfusion in MC twin pregnancy with selective FGR is unknown. This study evaluates the human placental GLUT1 and GLUT3 gene expression in MC twin gestations with selective FGR. METHODS: MC twin pregnancy with selective FGR was defined as the presence of inter-twin birth weight discordance of > 25% and the smaller twin with a birth weight less than the 10th percentile in third trimester. Fetal umbilical artery Doppler was checked within 1 week before delivery in the two fetuses. An abnormal umbilical artery Doppler was defined as persistently absent or reverse end-diastolic flow (UA-AREDF). GLUT1, GLUT3 and HIF-1α gene expression were assayed in each twin's placental territories. The inter-twin placental gene expression ratio was calculated as the placenta GLUTs or HIF-1α expression level of the selective FGR twin divided by expression level of the appropriate-for-gestational-age (AGA) cotwin. Higher gene expression ratio means elevated gene expression in the selective FGR twin's placenta territory compared to AGA twin's placenta territory. RESULTS: 15 MC twin gestations with selective FGR including nine with normal (group 1) and six with abnormal selective FGR twin UA Doppler (group 2) were included into this study. The GLUT3 and HIF-1α gene expression are significantly elevated in selective FGR twin's placenta territory in group 2 twin pregnancies (mean gene expression ratio as 2.23 and 1.65, p values as 0.015 and 0.045, respectively), but not in in group 1 twin pregnancies. CONCLUSION: The upregulation of placental GLUT3 gene expression in selective FGR fetus with abnormal UA Doppler may be due to hypo-perfusion which is mediated by up -regulation of HIF-1α gene expression.

Electroacupuncture suppresses glucose metabolism and GLUT-3 expression in medial prefrontal cortical in rats with neuropathic pain.

BACKGROUND: Accumulating evidence has demonstrated that the electroacupuncture (EA) stimulation could effectively alleviate neuropathic pain. The medial prefrontal cortex (mPFC) is a vital part of the cortical representation of pain in the brain, and its glucose metabolism is mostly affected in the progression of pain. However, the central mechanism of EA analgesia remains unclear. METHODS: Fifty-four male SD rats were equally randomized into sham surgery (Sham) group, chronic constriction injury (CCI) group and EA stimulation (EA) group. The CCI model, involving ligature of the right sciatic nerve, was established in all animals except the Sham group. EA stimulation was applied on the right side acupoints of Huantiao (GB30) and Yanglingquan (GB34) in the EA group. Paw withdrawal threshold (PWT) and paw thermal withdrawal latency (PWL) were measured. The 18 F-fluorodeoxyglucose positron emission tomography (FDG-PET) was used to evaluate glucose metabolism changes in the mPFC. The expression of glucose transporter 3 (GLUT-3) in the mPFC was determined by immune histochemistry and ELISA. RESULTS: Comparing with CCI groups, EA treatment was obviously reversed CCI-induced mechanical allodynia (P < 0.01), thermal hyperalgesia (P < 0.01) and the increase of glucose metabolism in the left mPFC (P < 0.05). Furthermore, EA treatment significantly decreased the protein expression of GLUT-3 in the left mPFC (P < 0.01). CONCLUSIONS: Our results indicate that EA analgesia effect may be related to suppressing the glucose metabolism and GLUT-3 expression in the mPFC. This study could provide a potential insight into the central mechanisms involved in the analgesic effect of EA.

Hypoxia preconditioning protects neuronal cells against traumatic brain injury through stimulation of glucose transport mediated by HIF-1α/GLUTs signaling pathway in rat.

Hypoxia preconditioning (HPC), a well-established preconditioning model, has been shown to protect the brain against severe hypoxia or ischemia caused by traumatic brain injury (TBI), but the mechanism has not been well elucidated. Anaerobic glycolysis is the major way for neurons to produce energy under cerebral ischemia and hypoxia after TBI, and it requires large amounts of glucose. We hypothesized that glucose transport, as a rate-limiting step of glucose metabolism, may play key roles in the neuroprotective effects of HPC on cerebral cortex tissue against TBI. The aim of this study was to investigate the effect of HPC on glucose transport activity of rat cerebral cortex tissue after TBI through examining the gene expression of two major glucose transporters (GLUT1 and GLUT3) and their upstream target gene hypoxia-inducible factor-1α (HIF-1α). Sprague-Dawley rats were treated with HPC (50.47 kPa, 3 h/d, 3d). Twenty-four hours after the last treatment, the rats were injured using the Feeney free falling model. Cortex tissues of injured rats were removed at 1 h, 4 h, 8 h, 12 h, 1 day, 3 days, 7 d, and 14 days post-injury for histological analysis. Compared with TBI alone, HPC before TBI resulted in the expression of HIF-1α, GLUT1, and GLUT3 to increase at 1 h; they were markedly increased at 4 h, 8 h, 12 h, 1 day, and 3 days and decreased thereafter (p < 0.05). HPC before TBI could improve neuronal survival in rats by examining NeuN staining and observing reduced apoptosis by examining TUNEL staining. The result showed that HPC before TBI could increase the expression of GLUT1 and GLUT3. And through double immunofluorescence staining for GLUT3 and NeuN, the results strongly suggest that HPC improved glucose transport activity of neurons in rats with TBI. In summary, our results further support that HPC can improve hypoxia tolerance and attenuate neuronal loss of cerebral cortex in rats after TBI. The mechanism is mainly related to the increase of glucose transport activity through inducing GLUT1 and GLUT3 expression through upregulating HIF-1α expression.

Sex-dimorphic moderate hypoglycemia preconditioning effects on Hippocampal CA1 neuron bio-energetic and anti-oxidant function.

Hypoglycemia is a detrimental complication of rigorous management of type 1 diabetes mellitus. Moderate hypoglycemia (MH) preconditioning of male rats partially affords protection from loss of vulnerable brain neurons to severe hypoglycemia (SH). Current research investigated whether MH preconditioning exerts sex-dimorphic effects on hippocampal CA1 neuron bio-energetic and anti-oxidant responses to SH. SH up-regulated CA1 glucose or monocarboxylate transporter proteins in corresponding hypoglycemia-naïve male versus female rats; precedent MH amplified glucose transporter expression in SH irrespective of sex. Sex-differentiating SH effects on glycolytic and tricarboxylic pathway markers correlated with elevated tissue ATP content and diminished CA1 5'-AMP-activated protein kinase (AMPK) activation in females. MH-preconditioned suppression of mitochondrial energy pathway enzyme profiles and tissue ATP in SH rats coincided with amplified CA1 AMPK activity in both sexes. Anti-oxidative stress enzyme protein responses to SH were primarily sex-contingent; preconditioning amplified most of these profiles, yet exacerbated expression of lipid and protein oxidation markers in SH male and female rats, respectively. Results show that MH preconditioning abolishes female CA1 neuron neuroprotection of positive energy balance through SH, resulting in augmented CA1 AMPK activity and oxidative injury and diminished tissue ATP in hypoglycemia-conditioned versus naïve rats in each sex. It is unclear if SH elicits differential rates of CA1 neuronal destruction in the two sexes, or how MH may impact sex-specific cell loss. Further research is needed to determine if molecular mechanism(s) that maintain female CA1 neuron metabolic stability in the absence of MH preconditioning can be leveraged for therapeutic prevention of hypoglycemic nerve cell damage.

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.

Early-Life Iron Deficiency Alters Glucose Transporter-1 Expression in the Adult Rodent Hippocampus.

BACKGROUND: Early-life iron deficiency (ID) impairs hippocampal energy production. Whether there are changes in glucose transporter (GLUT) expression is not known. OBJECTIVE: The aim of this study was to investigate whether early-life ID and the treatment iron dose alter brain regional GLUT expression in adult rats and mice. METHODS: In Study 1, ID was induced in male and female Sprague Dawley rat pups by feeding dams a 3-mg/kg iron diet during gestation and the first postnatal week, followed by treatment using low-iron [3-10 mg/kg; formerly iron-deficient (FID)-10 group], standard-iron (40-mg/kg; FID-40 group), or high-iron (400-mg/kg; FID-400 group) diets until weaning. The control group received the 40 mg/kg iron diet. GLUT1, GLUT3, hypoxia-inducible factor (HIF)-1α, and prolyl-hydroxylase-2 (PHD2) mRNA and protein expression in the cerebral cortex, hippocampus, striatum, cerebellum, and hypothalamus were determined at adulthood. In Study 2, the role of hippocampal ID in GLUT expression was examined by comparing the Glut1, Glut3, Hif1α, and Phd2 mRNA expression in adult male and female wild-type (WT) and nonanemic hippocampal iron-deficient and iron-replete dominant negative transferrin receptor 1 (DNTfR1-/-) transgenic mice. RESULTS: In Study 1, Glut1, Glut3, and Hif1α mRNA, and GLUT1 55-kDa protein expression was upregulated 20-33% in the hippocampus of the FID-10 group but not the FID-40 group, relative to the control group. Hippocampal Glut1 mRNA (-39%) and GLUT1 protein (-30%) expression was suppressed in the FID-400 group, relative to the control group. Glut1 and Glut3 mRNA expression was not altered in the other brain regions in the 3 FID groups. In Study 2, hippocampal Glut1 (+14%) and Hif1α (+147%) expression was upregulated in the iron-deficient DNTfR1-/- mice, but not in the iron-replete DNTfR1-/- mice, relative to the WT mice (P < 0.05, all). CONCLUSIONS: Early-life ID is associated with altered hippocampal GLUT1 expression in adult rodents. The mouse study suggests that tissue ID is potentially responsible.

Insulin Receptor and Glucose Transporters in the Mammalian Cochlea.

Insulin receptors are expressed on nerve cells in the mammalian brain, but little is known about insulin signaling and the expression of the insulin receptor (IR) and glucose transporters in the cochlea. We performed immunohistochemistry and gene/protein expression analysis to characterize the expression pattern of the IR and glucose transporters in the mouse organ of Corti (OC). We also performed glucose uptake assays to explore the action of insulin and the effects of pioglitazone, an insulin sensitizer, on glucose transport in the OC. Western blots of protein extracts from OCs showed high expression of IR and glucose transporter 3 (GLUT3). Immunohistochemistry demonstrated that the IR is specifically expressed in the supporting cells of the OC. GLUT3 was found in outer and inner hair cells, in the basilar membrane (BM), the stria vascularis (SV), Reissner's membrane and spiral ganglion neurons (SGN). Glucose transporter 1 (GLUT1) was detected at low levels in the BM, SV and Reissner's membrane, and showed high expression in the SGN. Fluorescence glucose uptake assays revealed that hair cells take up glucose and that addition of insulin (10 nM or 1 µM) approximately doubled the rate of uptake. Pioglitazone conferred a small but nonsignificant potentiation of glucose uptake at the highest concentration of insulin. Gene expression analysis confirmed expression of IR, GLUT1 and GLUT3 mRNA in the OC. Pioglitazone significantly upregulated IR and GLUT1 mRNA expression, which was further increased by insulin. Together, these data show that insulin-stimulated glucose uptake occurs in the OC and may be associated with upregulation of both the IR and GLUT1.

Yin Yang 1 promotes the Warburg effect and tumorigenesis via glucose transporter GLUT3.

Cancer cells typically shift their metabolism to aerobic glycolysis to fulfill the demand of energy and macromolecules to support their proliferation. Glucose transporter (GLUT) family-mediated glucose transport is the pacesetter of aerobic glycolysis and, thus, is critical for tumor cell metabolism. Yin Yang 1 (YY1) is an oncogene crucial for tumorigenesis; however, its role in tumor cell glucose metabolism remains unclear. Here, we revealed that YY1 activates GLUT3 transcription by directly binding to its promoter and, concomitantly, enhances tumor cell aerobic glycolysis. This regulatory effect of YY1 on glucose entry into the cells is critical for YY1-induced tumor cell proliferation and tumorigenesis. Intriguingly, YY1 regulation of GLUT3 expression, and, subsequently, of tumor cell aerobic glycolysis and tumorigenesis, occurs p53-independently. Our results also showed that clinical drug oxaliplatin suppresses colon carcinoma cell proliferation by inhibiting the YY1/GLUT3 axis. Together, these results link YY1's tumorigenic potential with the critical first step of aerobic glycolysis. Thus, our novel findings not only provide new insights into the complex role of YY1 in tumorigenesis but also indicate the potential of YY1 as a target for cancer therapy irrespective of the p53 status.

2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-ß-d-pyranoside confers neuroprotection in cell and animal models of ischemic stroke through calpain1/PKA/CREB-mediated induction of neuronal glucose transporter 3.

Salidroside is proven to be a neuroprotective agent of natural origin, and its analog, 2-(4-Methoxyphenyl)ethyl-2-acetamido-2-deoxy-ß-d-pyranoside (named SalA-4g), has been synthesized in our lab. In this study, we showed that SalA-4g promoted neuronal survival and inhibited neuronal apoptosis in primary hippocampal neurons exposed to oxygen and glucose deprivation (OGD) and in rats subjected to ischemia by transient middle cerebral artery occlusion (MCAO), respectively, and that SalA-4g was more neuroprotective than salidroside. We further found that SalA-4g elevated glucose uptake in OGD-injured primary hippocampal neurons and increased the expression and recruitment of glucose transporter 3 (GLUT3) in ischemic brain. Signaling analysis revealed that SalA-4g triggered the phosphorylation of CREB, and increased the expression of PKA RII in primary hippocampal neurons exposed to OGD injury, while inhibition of PKA/CREB by H-89 alleviated the elevation in glucose uptake and GLUT3 expression, and blocked the protective effects of SalA-4g. Moreover, SalA-4g was noted to inhibit intracellular Ca(2+) influx and calpain1 activation in OGD-injured primary hippocampal neurons. Our results suggest that SalA-4g neuroprotection might be mediated by increased glucose uptake and elevated GLUT3 expression through calpain1/PKA/CREB pathway.

Drug-drug interactions between propofol and ART drugs: Inhibiting neuronal activity by affecting glucose metabolism.

BACKGROUND: The use of two or more drugs carries the potential risk of drug-drug interactions (DDIs), which may result in adverse reactions. Some human immunodeficiency virus (HIV)-infected patients who receive antiretroviral therapy (ART) may require general anesthesia with propofol (PRL) before undergoing surgical treatment. Both PRL and ART drugs may lead to neuronal dysfunction, which can be accompanied by energy metabolism disorders. Neurons take in glucose mainly through glucose transporter 3 (Glut3) which is specifically expressed on the cell membranes of neurons. However, to date, no study has examined whether the DDIs of PRL and ART drugs interfere with glucose metabolism and Glut3 expression in neurons. METHODS: An in vitro model was constructed using the primary cultures of neurons. PRL and ART drugs (EFV, AZT, and 3TC), were added at different concentrations (low, medium, and high). The neurons were exposed to the drugs for 1, 4, 8, and 12 h. The optimal drug concentration and exposure time were selected. The cellular survival rate, glucose concentration, electrophysiology, and the expression of Glut3 were detected. RESULTS: There were no significant changes in the cellular survival rates of the neurons that were exposed to both PRL and ART drugs at low concentrations for 1 h. However, the survival rates of the neurons decreased significantly as the drug concentrations and durations increased. The glucose concentration of the neurons that were exposed to both PRL and the ART drugs was significantly decreased. The glucose concentration of the neurons was not affected by any individual drug. The amplitude of the action potential and the expression of Glut3 were decreased in the neurons that were exposed to both PRL and ART drugs. CONCLUSIONS: The main adverse reactions induced by the DDIs between PRL and the ART drugs were decreased glucose metabolism and neuronal damage, which were caused by inhibiting the expression of Glut3. More importantly, we found that decreases in glucose metabolism predated neuronal damage.

Neurodevelopment Is Dependent on Maternal Diet: Placenta and Brain Glucose Transporters GLUT1 and GLUT3.

Glucose is the primary energy source for most mammalian cells and its transport is affected by a family of facilitative glucose transporters (GLUTs) encoded by the SLC2 gene. GLUT1 and GLUT3, highly expressed isoforms in the blood-brain barrier and neuronal membranes, respectively, are associated with multiple neurodevelopmental disorders including epilepsy, dyslexia, ADHD, and autism spectrum disorder (ASD). Dietary therapies, such as the ketogenic diet, are widely accepted treatments for patients with the GLUT1 deficiency syndrome, while ameliorating certain symptoms associated with GLUT3 deficiency in animal models. A ketogenic diet, high-fat diet, and calorie/energy restriction during prenatal and postnatal stages can also alter the placental and brain GLUTs expression with long-term consequences on neurobehavior. This review focuses primarily on the role of diet/energy perturbations upon GLUT isoform-mediated emergence of neurodevelopmental and neurodegenerative disorders.

Effects of Empagliflozin on Diuretics Reduction in Outpatient Heart Failure Patients.

Background and Objectives: Inhibitors of sodium-glucose cotransporter 2 (SGLT2i) reduce the risk of hospitalization for heart failure (HF). We aimed to examine the effect of empagliflozin on change of diuretics dose in outpatient HF patients. Methods: We retrospectively reviewed the medical records of 612 patients who were treated using both empagliflozin and diuretics. We excluded patients who did not meet the criteria for HF. Dose and duration of empagliflozin and diuretics were measured. Results: Of 612 patients, a total of 251 was analyzed and followed for a mean 430.0±175.4 days. The mean age was 69.3, 51.8% were female, and 93.2% had type 2 diabetes. The distribution of initial diuretics type when starting empagliflozin showed that furosemide comprised 24.7%, spironolactone 20.7%, thiazide 36.9%, and others. Total 23.1% of patients reduced diuretic dose, 13.1% increased diuretic dose, 41.4% continued at the same diuretic dose, and 22.3% switched to different diuretics. Among patients who were using furosemide, 36.0% reduced diuretics dose. There was a diuretic reduction in 22.6% of HF preserved ejection fraction (HFpEF, left ventricular ejection fraction [LVEF] ≥50%) and in 26.5% of HF reduced EF (HFrEF, LVEF <50%). The average doses furosemide at the start of empagliflozin decreased from 16.3mg/day to 8.5mg/day at the time of follow-up. Conclusions: Among outpatient clinic HF patients treated with both diuretics and empagliflozin, 23.1% of patients had their diuretics reduced, and the mean dose of furosemide was reduced by about half. This suggests that empagliflozin has clinical advantages in managing outpatient HF patients.

Expression and Prognostic Value of Glucose Transporter 3 in Diffuse Large B Cell Lymphoma.

BACKGROUND: Several reports have suggested that glucose transporter 3 (GLUT-3) promotes tumor metastasis. The aim of this study was to examine the relationship between the expression level of GLUT-3 and the prognosis of patients with diffuse large B cell lymphoma (DLBCL). METHODS: The GLUT-3 expression levels in 91 DLBCL patients were evaluated by immunohistochemistry. The relationships between GLUT-3 expression level and clinicopathological characteristics and progression-free survival (PFS) of DLBCL patients were analyzed. The use of validation cohorts confirmed the predictive value of GLUT-3 expression. The correlation between GLUT-3 and immune cell infiltration was investigated using the Cell-type Identification By Estimating Relative Subsets Of RNA Transcripts system and the analysis of the infiltrating score was obtained by single sample Gene Set Enrichment Analysis. RESULTS: Expression of GLUT-3, which is highly expressed in DLBCL patients, was significantly associated with elevated serum LDH level, recurrence and Ki-67 status. Kaplan-Meier analysis showed that high GLUT-3 expression levels in DLBCL were related to poor PFS. Univariate and multivariate analyses results showed that low GLUT-3 expression level was significantly but independently associated with favorable PFS in DLBCL patients. GLUT-3 expression was also correlated with immune cell infiltration and the analysis of the infiltrating score. CONCLUSION: Our results indicate that GLUT-3 may act as a potential independent prognostic factor in DLBCL patients. The difference of the immune microenvironment in DLBCL patients may be predicted by the expression level of GLUT-3.

GLUT3 Promotes Epithelial-Mesenchymal Transition via TGF-ß/JNK/ATF2 Signaling Pathway in Colorectal Cancer Cells.

Glucose transporter (GLUT) 3, a member of the GLUTs family, is involved in cellular glucose utilization and the first step in glycolysis. GLUT3 is highly expressed in colorectal cancer (CRC) and it leads to poor prognosis to CRC patient outcome. However, the molecular mechanisms of GLUT3 on the epithelial-mesenchymal transition (EMT) process in metastatic CRC is not yet clear. Here, we identified that activation of the c-Jun N-terminal kinase (JNK)/activating transcription factor-2 (ATF2) signaling pathway by transforming growth factor-ß (TGF-ß) promotes GLUT3-induced EMT in CRC cells. The regulation of GLUT3 expression was significantly associated with EMT-related markers such as E-cadherin, α- smooth muscle actin (α-SMA), plasminogen activator inhibitor-1 (PAI-1), vimentin and zinc finger E-box binding homeobox 1 (ZEB1). We also found that GLUT3 accelerated the invasive ability of CRC cells. Mechanistically, TGF-ß induced the expression of GLUT3 through the phosphorylation of JNK/ATF2, one of the SMAD-independent pathways. TGF-ß induced the expression of GLUT3 by increasing the phosphorylation of JNK, the nuclear translocation of the ATF2 transcription factor, and the binding of ATF2 to the promoter region of GLUT3, which increased EMT in CRC cells. Collectively, our results provide a new comprehensive mechanism that GLUT3 promotes EMT process through the TGF-ß/JNK/ATF2 signaling pathway, which could be a potential target for the treatment of metastatic CRC.

Gestational Diabetes Mellitus-Associated Hyperglycemia Impairs Glucose Transporter 3 Trafficking in Trophoblasts Through the Downregulation of AMP-Activated Protein Kinase.

AMP-activated protein kinase (AMPK) is an important regulator of glucose metabolism, and glucose transporter 3 (GLUT3) is an efficient glucose transporter in trophoblasts. Whether placental AMPK and GLUT3 respond accordingly to gestational diabetes mellitus (GDM) remains uncertain. Here, we explored the regulatory role of AMPK in the GLUT3-dependent uptake of glucose by placental trophoblasts and the viability of the cells. In this study, the level of glycolysis in normal and GDM-complicated placentas was assessed by LC-MS/MS. The trophoblast hyperglycemia model was induced by the incubation of HTR8/SVneo cells with a high glucose concentration. GDM animal models were generated with db/ + mice and C57BL/6J mice fed a high-fat diet, and AMPK was manipulated by the oral administration of metformin. The uptake of glucose by trophoblasts was assessed using 2-NBDG or 2-deoxy-D-[3H] glucose. The results showed that GDM is associated with impaired glycolysis, AMPK activity, GLUT3 expression in the plasma membrane (PM) and cell survival in the placenta. Hyperglycemia induced similar changes in trophoblasts, and these changes were rescued by AMPK activation. Both hyperglycemic db/ + and high-fat diet-induced GDM mice exhibited a compromised AMPK-GLUT3 axis and suppressed cell viability in the placenta as well as excessive fetal growth, and all of these effects were partially alleviated by metformin. Taken together, our findings support the notion that AMPK activation upregulates trophoblast glucose uptake by stimulating GLUT3 translocation, which is beneficial for viability. Thus, the modulation of glucose metabolism in trophoblasts by targeting AMPK might ameliorate the adverse intrauterine environment caused by GDM.

Downregulation of GLUT3 impairs STYK1/NOK-mediated metabolic reprogramming and proliferation in NIH-3T3 cells.

Serine threonine tyrosine kinase 1 (STYK1)/novel oncogene with kinase domain (NOK) has been demonstrated to promote cell carcinogenesis and tumorigenesis, as well as to strengthen cellular aerobic glycolysis, which is considered to be a defining hallmark of cancer. As the carriers of glucose into cells, glucose transporters (GLUTs) are important participants in cellular glucose metabolism and even tumorigenesis. However, to the best of our knowledge, the role of GLUTs in biological events caused by STYK1/NOK has not yet been reported. The present study assessed GLUT3 as a key transporter, and glucose consumption and lactate production assays revealed that downregulation of GLUT3 impaired STYK1/NOK-induced augmented glucose uptake and lactate production, and RT-qPCR and western blotting confirmed that GLUT3 knockdown attenuated the STYK1/NOK-induced increase in the expression levels of key enzymes implicated in glycolysis. Furthermore, MTT and Transwell assays demonstrated that STYK1/NOK-triggered cell proliferation and migration were also markedly decreased following knockdown of GLUT3. To the best of our knowledge, the present study is the first to demonstrate that GLUT3 serves a prominent role in STYK1/NOK-driven aerobic glycolysis and cell proliferation characteristics. These findings may provide a clue for the investigation of the oncogenic activity of STYK1/NOK and for the identification of potential tumor therapy targets associated with GLUT3.

Effect of Zhenxin Xingshui Yizhi Fang on Aß25-35 induced expression of related transporters in HBMEC cell model.

ETHNOPHARMACOLOGICAL RELEVANCE: Aß (ß-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 Aß25-35-induced apoptosis in cultured human brain microvascular endothelial cells (HBMEC) and its potential mechanism were investigated. MATERIALS AND METHODS: HBMEC cells were treated with Aß25-35 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 Aß25-35-induced apoptosis was characterized by Hoechst-33258 and the activity of cysteinyl aspartate specific proteinase-3. The expression level of Aß1-42 in cells induced by Aß25-35 was measured by human Aß1-42 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 Aß25-35 induced neurotoxic cells, the percentage of apoptotic cells, the concentration of Aß1-42 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 Aß1-42 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 Aß25-35, inhibit apoptosis, and regulate the transport of Aß on BBB and energy metabolism disorder in HBMEC.