Sodium-dependent glucose transporter 2 inhibitors effects on myocardial function in patients with type 2 diabetes and asymptomatic heart failure

BACKGROUND Sodium-dependent glucose transporter 2 inhibitors(SGLT2i)have shown efficacy in reducing heart failure(HF)burden in a very heterogeneous groups of patients,raising doubts about some contemporary assumptions of their mechanism of action.We previously published a prospective observational study that evaluated mechanisms of action of SGLT2i in patients with type 2 diabetes who were in HF stages A and B on dual hypoglycemic therapy.Two groups of patients were included in the study:the ones receiving SGLT2i as an add-on agent to metformin and the others on dipeptidyl peptidase-4 inhibitors as an add-on to metformin due to suboptimal glycemic control.AIM To evaluate the outcomes regarding natriuretic peptide,oxidative stress,inflammation,blood pressure,heart rate,cardiac function,and body weight.METHODS The study outcomes were examined by dividing each treatment arm into two subgroups according to baseline parameters of global longitudinal strain(GLS),N-terminal pro-brain natriuretic peptide,myeloperoxidase(MPO),high-sensitivity C-reactive protein(hsCRP),and systolic and diastolic blood pressure.To evaluate the possible predictors of observed changes in the SGLT2i arm during follow-up,a rise in stroke volume index,body mass index(BMI)decrease,and lack of heart rate increase,linear regression analysis was performed.RESULTS There was a greater reduction of MPO,hsCRP,GLS,and blood pressure in the groups with higher baseline values of mentioned parameters irrespective of the therapeutic arm after 6 months of follow-up.Significant independent predictors of heart rate decrease were a reduction in early mitral inflow velocity to early diastolic mitral annular velocity at the interventricular septal annulus ratio and BMI,while the predictor of stroke volume index increase was SGLT2i therapy itself.CONCLUSION SGLT2i affect body composition,reduce cardiac load,improve diastolic/systolic function,and attenuate the sympathetic response.Glycemic control contributes to the improvement of heart function,blood pressure control,oxidative stress,and reduction in inflammation.

Value of glucose transport protein 1 expression in detecting lymph node metastasis in patients with colorectal cancer

BACKGROUND There are limited data on the use of glucose transport protein 1(GLUT-1)expre-ssion as a biomarker for predicting lymph node metastasis in patients with colorectal cancer.GLUT-1 and GLUT-3,hexokinase(HK)-II,and hypoxia-induced factor(HIF)-1 expressions may be useful biomarkers for detecting primary tumors and lymph node metastasis when combined with fluorodeoxyglucose(FDG)uptake on positron emission tomography/computed tomography(PET/CT).AIM To evaluate GLUT-1,GLUT-3,HK-II,and HIF-1 expressions as biomarkers for detecting primary tumors and lymph node metastasis with 18F-FDG-PET/CT.METHODS This retrospective study included 169 patients with colorectal cancer who underwent colectomy and preoperative 18F-FDG-PET/CT at Chungbuk National University Hospital between January 2009 and May 2012.Two tissue cores from the central and peripheral areas of the tumors were obtained and were examined by a dedicated pathologist,and the expressions of GLUT-1,GLUT-3,HK-II,and HIF-1 were determined using immunohisto-chemical staining.We analyzed the correlations among their expressions,various clinicopathological factors,and the maximum standardized uptake value(SUVmax)of PET/CT.RESULTS GLUT-1 was found at the center or periphery of the tumors in 109(64.5%)of the 169 patients.GLUT-1 positivity was significantly correlated with the SUVmax of the primary tumor and lymph nodes,regardless of the biopsy site(tumor center,P<0.001 and P=0.012;tumor periphery,P=0.030 and P=0.010,respectively).GLUT-1 positivity and negativity were associated with higher and lower sensitivities of PET/CT,respectively,for the detection of lymph node metastasis,regardless of the biopsy site.GLUT3,HK-II,and HIF-1 expressions were not significantly correlated with the SUVmax of the primary tumor and lymph nodes.CONCLUSION GLUT-1 expression was significantly correlated with the SUVmax of 18F-FDG-PET/CT for primary tumors and lymph nodes.Clinicians should consider GLUT-1 expression in preoperative endoscopic biopsy in interpreting PET/CT findings.

Effects of sodium-dependent glucose transporter 2 inhibitors in patients with type 2 diabetes mellitus and asymptomatic heart failure

Sodium-dependent glucose transporter 2 inhibitors(SGLT2i)have been increa-singly used with proven efficacy in patients with heart failure(HF),regardless of diabetes status.GrubićRotkvićet al recently published an observational study on SGLT2i therapy in patients with type 2 diabetes mellitus and asymptomatic HF.They found that the use of SGLT2i led to reduced cardiac load and improved cardiovascular performance,reinforcing the evolving paradigm that SGLT2i are not merely glucose-lowering agents but are integral to the broader management of cardiovascular risk in patients with type 2 diabetes mellitus.The study by GrubićRotkvićet al contributes to the growing body of literature supporting the early use of SGLT2i in patients with diabetic cardiomyopathy,offering a potential strategy to mitigate the progression of HF.Future larger studies should be con-ducted to confirm these findings,and explore the long-term cardiovascular bene-fits of SGLT2i,particularly in asymptomatic patients at risk of developing HF.

Effectiveness and mechanisms of sodium-dependent glucose transporter 2 inhibitors in type 2 diabetes and heart failure patients

We comment on an article by GrubićRotkvićet al published in the recent issue of the World Journal of Cardiology.We specifically focused on possible factors affecting the therapeutic effectiveness of sodium-dependent glucose transporter inhibitors(SGLT2i)in patients with type 2 diabetes mellitus(T2DM)and their impact on comorbidities.SGLT2i inhibits SGLT2 in the proximal tubules of the kidneys,lowering blood glucose levels by inhibiting glucose reabsorption by the kidneys and causing excess glucose to be excreted in the urine.Previous studies have demonstrated a role of SGLT2i in cardiovascular function in patients with diabetes who take metformin but still have poor glycemic control.In addition,SGLT2i has been shown to be effective in anti-apoptosis,weight loss,and cardiovascular protection.Accordingly,it is feasible to treat patients with T2DM with cardiovascular or renal diseases using SGLT2i.

Icariin ameliorates memory deficits through regulating brain insulin signaling and glucose transporters in 3×Tg-AD mice

Icariin,a major prenylated flavonoid found in Epimedium spp.,is a bioactive constituent of Herba Epimedii and has been shown to exert neuroprotective effects in experimental models of Alzheimer’s disease.In this study,we investigated the neuroprotective mechanism of icariin in an APP/PS1/Tau triple-transgenic mouse model of Alzheimer’s disease.We performed behavioral tests,pathological examination,and western blot assay,and found that memory deficits of the model mice were obviously improved,neuronal and synaptic damage in the cerebral cortex was substantially mitigated,and amyloid-βaccumulation and tau hyperphosphorylation were considerably reduced after 5 months of intragastric administration of icariin at a dose of 60 mg/kg body weight per day.Furthermore,deficits of proteins in the insulin signaling pathway and their phosphorylation levels were significantly reversed,including the insulin receptor,insulin receptor substrate 1,phosphatidylinositol-3-kinase,protein kinase B,and glycogen synthase kinase 3β,and the levels of glucose transporter 1 and 3 were markedly increased.These findings suggest that icariin can improve learning and memory impairments in the mouse model of Alzheimer’s disease by regulating brain insulin signaling and glucose transporters,which lays the foundation for potential clinical application of icariin in the prevention and treatment of Alzheimer’s disease.

Relationship Between Serum microRNA-372-3p and Glucose Transporter 4 Levels and Insulin Resistance in Gestational Diabetes Mellitus

Objective:To observe the changes in insulin resistance in patients with gestational diabetes mellitus(GDM)based on the detection of serum microRNA-372-3p and glucose transporter protein 4(GLUT4)levels.Methods:We conducted a retrospective cohort study of 42 patients who were diagnosed with GDM and hospitalized in our hospital during the period from January 2017 to December 2021 and another 42 patients who had normal pregnancy during the same period by collecting their clinical data.We analyzed their serum microRNA expression profiles and miR-372-3p levels to study the relationship between GDM and insulin resistance.Results:The relative expression of miR-372-3p in the serum of patients in the GDM group was significantly higher than that of patients in the control group,but the GLUT 4 level of the GDM group was significantly lower than that of the control group(P<0.05).Compared with the control group,the GDM group had significantly higher levels of fasting blood glucose(FBG),fasting insulin(FINS),2-hour postprandial blood glucose(2h-BG),total cholesterol(TC),triglyceride(TG),and homeostatic model assessment for insulin resistance(HOMA-IR)index but significantly lower homeostasis model assessment ofβ-cell function(HOMA-β)index(P<0.05).The relative expression of miR-372-3p in serum was independently and positively correlated with HOMA-IR,while the level of GLUT4 was independently and negatively correlated with HOMA-IR(P<0.05).Conclusion:Glycosylated hemoglobin test in the early stages of pregnancy(12–13 weeks of gestation)is important to ensure the health of pregnant women and fetuses.The screening and intervention for elevated glucose in pregnant women act as a guideline for the treatment of GDM.Patients with insulin resistance and related complications such as hyperinsulinemia and hypoglycemia should be given priority.

Effects of electroacupuncture on microcirculatory blood flow and glucose transporter function in the hippocampus

Nerve cell metabolism in post brain ischemia depends on increased microcirculation perfusion and transport function of microvascular endothelial cells. In the present study, a rat model of middle cerebral artery occlusion was established to investigate the influence of electroacupuncture （EA） on hippocampal CA1 cerebral blood flow and glucose transporter 1 （GLUT1） expression in the microvascular endothelial cells. Following EA at Neiguan （PC 6）, the cerebral blood flow in the ischemic hippocampal CA1 region was significantly elevated, the number and microvascular integrated absorbance of the GLUTl-positive cells were significantly increased, nerve cell damage was ameliorated, and GLUT1 protein expression in the ischemic hippocampus was significantly increased. Results demonstrate that EA increased the cerebral blood flow of the hippocampal CA1 region and improved the glucose transport function, thereby attenuating neuronal injuries.

Transforming growth factor beta-1 upregulates glucose transporter 1 and glycolysis through canonical and noncanonical pathways in hepatic stellate cells

BACKGROUND Hepatic stellate cells(HSCs)are the key effector cells mediating the occurrence and development of liver fibrosis,while aerobic glycolysis is an important metabolic characteristic of HSC activation.Transforming growth factor-β1(TGF-β1)induces aerobic glycolysis and is a driving factor for metabolic reprogramming.The occurrence of glycolysis depends on a high glucose uptake level.Glucose transporter 1(GLUT1)is the most widely distributed glucose transporter in the body and mainly participates in the regulation of carbohydrate metabolism,thus affecting cell proliferation and growth.However,little is known about the relationship between TGF-β1 and GLUT1 in the process of liver fibrosis and the molecular mechanism underlying the promotion of aerobic glycolysis in HSCs.AIM To investigate the mechanisms of action of GLUT1,TGF-β1 and aerobic glycolysis in the process of HSC activation during liver fibrosis.METHODS Immunohistochemical staining and immunofluorescence assays were used to examine GLUT1 expression in fibrotic liver tissue.A Seahorse extracellular flux(XF)analyzer was used to examine changes in aerobic glycolytic flux,lactate production levels and glucose consumption levels in HSCs upon TGF-β1 stimulation.The mechanism by which TGF-β1 induces GLUT1 protein expression in HSCs was further explored by inhibiting/promoting the TGF-β1/mothersagainst-decapentaplegic-homolog 2/3(Smad2/3)signaling pathway and inhibiting the p38 and phosphoinositide 3-kinase(PI3K)/AKT signaling pathways.In addition,GLUT1 expression was silenced to observe changes in the growth and proliferation of HSCs.Finally,a GLUT1 inhibitor was used to verify the in vivo effects of GLUT1 on a mouse model of liver fibrosis.RESULTS GLUT1 protein expression was increased in both mouse and human fibrotic liver tissues.In addition,immunofluorescence staining revealed colocalization of GLUT1 and alpha-smooth muscle actin proteins,indicating that GLUT1 expression was related to the development of liver fibrosis.TGF-β1 caused an increase in aerobic glycolysis in HSCs and induced GLUT1 expression in HSCs by activating the Smad,p38 MAPK and P13K/AKT signaling pathways.The p38 MAPK and Smad pathways synergistically affected the induction of GLUT1 expression.GLUT1 inhibition eliminated the effect of TGF-β1 on HSC proliferation and migration.A GLUT1 inhibitor was administered in a mouse model of liver fibrosis,and GLUT1 inhibition reduced the degree of liver inflammation and liver fibrosis.CONCLUSION TGF-β1 induces GLUT1 expression in HSCs,a process related to liver fibrosis progression.In vitro experiments revealed that TGF-β1-induced GLUT1 expression might be one of the mechanisms mediating the metabolic reprogramming of HSCs.In addition,in vivo experiments also indicated that the GLUT1 protein promotes the occurrence and development of liver fibrosis.

Effects of octreotide on glucose transporter type 2expression in obese rat small intestine

AIM： TO investigate the effects of the somatostatin analogue, octreotide, on maltose and sucrase activities and expression of glucose transporter type 2 （GLUT2） in obese rat intestinal mucosa. METHODS： We divided 49 Sprague-Dawley rats into a group of 31 high fat diet-induced obese rats and a group of 18 normal controls. The obese rats were separated into an octreotide treated group 9f 16 rats and an obese group of 15. The intervention （：jroup was injected with octreotide at 40 ±g/kg body weight every 12 h for 8 d. Rat body weight was measured weekly to calculate Lee＇s index. After euthanization, maltase and sucrase activities in the small intestine were measured by activity assays, and the fasting plasma glucose level was measured. The expression of GLUT2 in small intestinal mucosa was analyzed by immunohistochemistry, reverse transcriptase polymerase chain reaction and Western blotting assays. RESULTS： Body weight, Lee＇s index, fasting plasma glucose level, maltase activity in small intestinal mucosa, mucosa and apical GLUT2, GLUT2 mRNA and protein expression levels were all significantly higher in the obese group than in the normal control group （605.61 ± 141.00 vs 378.54 ±111.75, 337.61 ± 10.82 vs 318.73 ± 20.10, 8.60± 1.38 vs 7.33 ± 0.70, 156.01 ± 58.81 vs 50.43 ± 30.49, 390 744.2± 62 469.21 vs 170 546.50 ± 50 646.14, 26 740.18 ±3809.60 vs 354.98± 57.19, 0.26± 0.11 vs 0.07± 0.02, and 2.08 ± 0.59 vs 1.27 ± 0.38, respectively, all P 〈 0.01）. Sucrase activity did not differ between the two groups. Octreotide intervention significantly decreased the body weight and fasting plasma glucose level of obese rats （508.27 ± 94.39 vs 605.61 ± 141.00, 7.58 ± 1.51 vs 8.60±1.38, respectively, all P 〈 0.05）. The intestinal mucosa and apical GLUT2, expression of GLUT2 mRNA and protein were also significantly lower in the octreotide intervention group than in the obese group （269 975.2 ± 53 730.94 vs 390 744.2 ± 62 469.21, 3758.06 ± 364.51 vs 26 740.18 ± 3809.60, 0.08 ± 0.02 vs 0.26 ±0.11, and 1.31 ± 0.27 vs 2.08 ±0.59, respectively, all P 〈 0.01）. CONCLUSION： High fat dietinduced obesity is associated with elevated intestinal maltase activity, GLUT2 expression, and permanent apical GLUT2 in the small intestinal mucosa of rats. Octreotide can inhibit these effects.

Current understanding of glucose transporter 4 expression and functional mechanisms

Glucose is used aerobically and anaerobically to generate energy for cells.Glucose transporters(GLUTs)are transmembrane proteins that transport glucose across the cell membrane.Insulin promotes glucose utilization in part through promoting glucose entry into the skeletal and adipose tissues.This has been thought to be achieved through insulin-induced GLUT4 translocation from intracellular compartments to the cell membrane,which increases the overall rate of glucose flux into a cell.The insulin-induced GLUT4 translocation has been investigated extensively.Recently,significant progress has been made in our understanding of GLUT4 expression and translocation.Here,we summarized the methods and reagents used to determine the expression levels of Slc2a4 mRNA and GLUT4 protein,and GLUT4 translocation in the skeletal muscle,adipose tissues,heart and brain.Overall,a variety of methods such real-time polymerase chain reaction,immunohistochemistry,fluorescence microscopy,fusion proteins,stable cell line and transgenic animals have been used to answer particular questions related to GLUT4 system and insulin action.It seems that insulininduced GLUT4 translocation can be observed in the heart and brain in addition to the skeletal muscle and adipocytes.Hormones other than insulin can induce GLUT4 translocation.Clearly,more studies of GLUT4 are warranted in the future to advance of our understanding of glucose homeostasis.

Transcriptional activation of glucose transporter 1 in orthodontic tooth movement-associated mechanical response

The interplay between mechanoresponses and a broad range of fundamental biological processes, such as cell cycle progression,growth and differentiation, has been extensively investigated. However, metabolic regulation in mechanobiology remains largely unexplored. Here, we identified glucose transporter 1(GLUT1)—the primary glucose transporter in various cells—as a novel mechanosensitive gene in orthodontic tooth movement(OTM). Using an in vivo rat OTM model, we demonstrated the specific induction of Glut1 proteins on the compressive side of a physically strained periodontal ligament. This transcriptional activation could be recapitulated in in vitro cultured human periodontal ligament cells(PDLCs), showing a time-and dose-dependent mechanoresponse. Importantly, application of GLUT1 specific inhibitor WZB117 greatly suppressed the efficiency of orthodontic tooth movement in a mouse OTM model, and this reduction was associated with a decline in osteoclastic activities. A mechanistic study suggested that GLUT1 inhibition affected the receptor activator for nuclear factor-κ B Ligand(RANKL)/osteoprotegerin(OPG)system by impairing compressive force-mediated RANKL upregulation. Consistently, pretreatment of PDLCs with WZB117 severely impeded the osteoclastic differentiation of co-cultured RAW264.7 cells. Further biochemical analysis indicated mutual regulation between GLUT1 and the MEK/ERK cascade to relay potential communication between glucose uptake and mechanical stress response. Together, these cross-species experiments revealed the transcriptional activation of GLUT1 as a novel and conserved linkage between metabolism and bone remodelling.

Hepatic expression and cellular distribution of the glucose transporter family

Glucose and other carbohydrates are transported into cells using members of a family of integral membrane glucose transporter (GLUT) molecules. To date 14 members of this family, also called the solute carrier 2A proteins have been identified which are divided on the basis of transport characteristics and sequence similarities into several families (Classes 1 to 3). The expression of these different receptor subtypes varies between different species, tissues and cellular subtypes and each has differential sensitivities to stimuli such as insulin. The liver is a contributor to metabolic carbohydrate homeostasis and is a major site for synthesis, storage and redistribution of carbohydrates. Situations in which the balance of glucose homeostasis is upset such as diabetes or the metabolic syndrome can lead metabolic disturbances that drive chronic organ damage and failure, confirming the importance of understanding the molecular regulation of hepatic glucose homeostasis. There is a considerable literature describing the expression and function of receptors that regulate glucose uptake and release by hepatocytes, the most import cells in glucose regulation and glycogen storage. However there is less appreciation of the roles of GLUTs expressed by non parenchymal cell types within the liver, all of which require carbohydrate to function. A better understanding of the detailed cellular distribution of GLUTs in human liver tissue may shed light on mechanisms underlying disease pathogenesis. This review summarises the available literature on hepatocellular expression of GLUTs in health and disease and highlights areas where further investigation is required.

Uses of knockout,knockdown,and transgenic models in the studies of glucose transporter 4

Currently,glucose transporter 4(GLUT4)has been considered as the key player for the insulin-stimulated glucose transport in the muscle and adipose tissues.The development of recombinant DNA techniques allows the creations of genetically knockout,knockdown and transgenic animals and cells for the study of GLUT4’s physiological functions.Here,we have used key words to search the PubMed and summarized the methods used in Slc2a4 gene knockout,GLUT4 knockdown and overexpression in the whole body and tissue specific manner.The whole body GLUT4-null mice have growth retardation,but normal glucose tolerance and basal glucose turnover rates.Compared with whole body Slc2a4 knockout mice,adipose and muscle double knockout mice have impaired insulin tolerance and glucose intolerance.The results of GLUT4 knockdown in 3T3-L1 adipocytes have shown that its expression is needed for lipogenesis after,but not during,differentiation.Transgenic mice with the whole body GLUT4 overexpression have normal body weight and lowered blood glucose level.The adipose tissue specific overexpression of GLUT4 leads to increases in mouse body weight and adipose tissue weight.The insulin-stimulated GLUT4 translocation in the skeletal muscle contributes to the regulation of glucose homeostasis.Data from both transgenic overexpression and tissue specific Slc2a4 knockout indicate that GLUT4 probably plays a role in the glucose uptake in the fasting state.More studies are warranted to use advanced molecular biology tools to decipher the roles of GLUT4 in the control of glucose homeostasis.

Effect of puerarin on the P13K pathway for glucose transportation and insulin signal transduction in adipocytes

To explore the effect of puerarin on insulin receptor （IR）, insulin receptor substrate-1 （IRS-1） and protein expression of protein kinase B （PKB） in the P13K pathway of the glucose consumption, transportation and insulin signal transduction in 3T3-L1 adipoeytes with insulin resistance. The insulin resistance 3T3-L1 adipocytes model was established by free fatty acid induction. The model cells were managed with puerarin in different concentrations. Glucose consumption was detected with glucose oxidase method, glucose transportation rate was determined by 2-deoxy-^3H glucose ingesting method, and the IR, IRS-1 and PKB expression were determined by Western blot. Glucose consumption and transportation were significantly decreased in the model adipoeytes, but increased after treated with puerarin （P 〈 0. 01 ）. Moreover, the level of tyrosine phosphorylation of IR subunit β was higher in the puerarin treated groups, and that of IRS-1 was higher in the group treated with low dose puerarin than that in the model group. The 3T3-L1 adipocytes of insulin resistance model could be induced by free fatty acid successfully, puerarin could promote the glucose utilization in them to alleviate the in- sulin resistance, which may be related with the action in advancing the tyrosine phosphorylation of IR and IRS-1.

The Saturation Characteristics of Glucose Transport in Bovine Retinal Pigment Epithelium

Purpose:To study the saturation characteristics of the glucose transport across the bovine retinal pigment epithelium(RPE).Methods:The bovine RPE preparations were munted with a modified Ussing chamber.The L-[^(3)H]-glucose and 3-0-methyl-D-[^(14)C]-glucose fluxes across the RPE from the choroid to retina were studied at different glucose concentrations.Results:The glucose transport was found to be stereospecific,with 3-0-methyl-D-glucose(MDG)being transported about three times faster than L-glucose.The glucose transport showed typical saturation characteristics in Michaelis-Menten fashion.The V_(max)and the K_(m)of corrected MDG were 2452 nmol cm^(-2)h^(-1)and 30.8 mM respectively.It was shown that the glucose transport system was saturated at 61.6 mM.Conclusions:The saturation characteristics of the corrected MDG flux suggested that the capacity of glucose transport through the bovine RPE is immense.

An Optimum Dose of Olive Leaf Extract Improves Insulin Receptor Substrate-1,Tyrosine Kinase,and Glucose Transporters,While High Doses Have Genotoxic and Apoptotic Effects

Type 2 diabetes is the most common type of diabetes. Conventionally many drugs are used for the treatment of diabetes such as biguanides, sulfonylureas, meglitinides, etc. But the desired effective treatment is still not to be achieved. So researches are going on for the development of effective alternative therapy against diabetes. Olive leaves are traditionally used in the treatment of the disease. However, studies on its mechanism of action are not yet enough. The aim of this study was to investigate whether olive leaf extract (OLE) improves insulin receptor substrate-1 (IRS-1), tyrosine kinase (TK), GLUT-2, and GLUT-4. Oleuropein levels were analyzed from OLE obtained by using four different solvents, and the highest content of methanol extract was selected for the study. Different concentrations of OLE (2.5 to 320 μg/mL) were incubated with hepatocellular carcinoma (HepG2) cells for 24 hours. After incubation, cell viability was assessed based on luminometric ATP cell viability assay kit. Intracellular reactive oxygen species (ROS) generating level was detected using 2,7dichlorodihydrofluorescein-diacetate (H2DCF-DA) fluorescent probes. Apoptosis was evaluated by acridine orange/ethidium bromide double staining method. Genotoxicity was evaluated by alkaline single cell gel electrophoresis assay (Comet Assay). Protein expression levels of IRS-1, TK, GLUT-2, and GLUT-4 were analyzed by western blotting technique from the obtained cell lysates. Although an optimum doses of OLE (10 μg/mL) maximally increased cell proliferation, decreased ROS generation improved IRS-1, TK, GLUT-2, and GLUT-4 protein expression levels (about fivefold), higher doses (10 to 320 μg/mL) markedly decreased the cell viability, increased DNA damage, apoptosis and ROS generation in a concentration-dependent manner. OLE can be used in the treatment of type 2 diabetes. However, in order to find the most effective and non-toxic concentration, dose optimization is required.

BcSDR1 is involved in regulation of glucose transport and cAMP and MAPK signaling pathways in Botrytis cinerea

Botrytis cinerea is a typical necrotrophic pathogenic fungus that causes severe diseases in a wide range of plant species, leading to significant economic losses. Our previous study showed that BcSDR1 positively regulates growth,development, and pathogenicity of B. cinerea. However, the regulation mechanism of BcSDR1 and the relationship between BcSDR1 and cAMP and MAPK signaling pathways are not well understood. In this study, transcriptome data showed that BcSDR1 is involved in glucose transmembrane transport, signal transduction, secondary metabolism, and other biological processes. BcSDR1 mutant(BCt41) showed remarkably weak sensitivity to cAMP and MAPK signaling pathways specific inhibitors, SQ22536 and U0126, and significantly decreased cAMP content. The key genes of cAMP and MAPK signaling pathways, BcGB1, BcBTP1, BcBOS1, BcRAS1, and BcBMP3 were significantly upregulated,whereas BcPLC1, BcBCG1, BcCDC4, BcSAK1, BcATF1, and BcBAP1 were significantly downregulated(P<0.05).BcSDR1 was obviously upregulated in BcBCG2, BcBCG3, BcPKA1, and BcPKAR RNA interference(RNAi) mutants, but significantly downregulated in BcPKA2, BcBMP1, and BcBMP3 RNAi mutants. Thus, BcBCG2, BcBCG3, BcPKA1, and BcPKAR negatively regulate BcSDR1 expression, whereas BcPKA2, BcBMP1, and BcBMP3 positively regulate BcSDR1expression.

METTL3 regulates glucose transporter expression in placenta exposed to hyperglycemia through the mTOR signaling pathway

Background:Alterations in the placental expression of glucose transporters(GLUTs),the crucial maternal-fetal nutrient transporters,have been found in women with hyperglycemia in pregnancy(HIP).However,there is still uncertainty about the underlying effect of the high-glucose environment on placental GLUTs expression in HIP.Methods:We quantitatively evaluated the activity of mammalian target of rapamycin(mTOR)and expression of GLUTs(GLUT1,GLUT3,and GLUT4)in the placenta of women with normal pregnancies(CTRL,n=12)and pregnant women complicated with poorly controlled type 2 diabetes mellitus(T2DM,n=12)by immunohistochemistry.In addition,BeWo cells were treated with different glucose concentrations to verify the regulation of hyperglycemia.Then,changes in the expression of GLUTs following the activation or suppression of the mTOR pathway were also assessed using MHY1485/rapamycin(RAPA)treatment or small interfering RNA(siRNA)-mediated silencing approaches.Moreover,we further explored the alteration and potential upstream regulatory role of methyltransferase-like 3(METTL3)when exposed to hyperglycemia.Results:mTOR,phosphorylated mTOR(p-mTOR),and GLUT1 protein levels were upregulated in the placenta of women with T2DM compared with those CTRL.In BeWo cells,mTOR activity increased with increasing glucose concentration,and the expression of GLUT1,GLUT3,and GLUT4 as well as GLUT1 cell membrane translocation were upregulated by hyperglycemia to varying degrees.Both the drug-mediated and genetic depletion of mTOR signaling in BeWo cells suppressed GLUTs expression,whereas MHY1485-induced mTOR activation upregulated GLUTs expression.Additionally,high glucose levels upregulated METTL3 expression and nuclear translocation,and decreasing METTL3 levels suppressed GLUTs expression and mTOR activity and vice versa.Furthermore,in METTL3 knockdown BeWo cells,the inhibitory effect on GLUTs expression was eliminated by activating the mTOR signaling pathway using MHY1485.Conclusion:High-glucose environment-induced upregulation of METTL3 in trophoblasts regulates the expression of GLUTs through mTOR signaling,contributing to disordered nutrient transport in women with HIP.

Role of melatonin receptor 1B gene polymorphism and its effect on the regulation of glucose transport in gestational diabetes mellitus

Melatonin receptor 1B(MT2,encoded by the MTNR1B gene),a high-affinity receptor for melatonin,is associated with glucose homeostasis including glucose uptake and transport.The rs10830963 variant in the MTNR1B gene is linked to glucose metabolism disorders including gestational diabetes mellitus(GDM);however,the relationship between MT2-mediated melatonin signaling and a high birth weight of GDM infants from maternal glucose abnormality remains poorly understood.This article aims to investigate the relationship between rs10830963 variants and GDM development,as well as the effects of MT2 receptor on glucose uptake and transport in trophoblasts.TaqMan-MGB(minor groove binder)probe quantitative realtime polymerase chain reaction(qPCR)assays were used for rs10930963 genotyping.MT2 expression in the placenta of GDM and normal pregnant women was detected by immunofluorescence,western blot,and qPCR.The relationship between MT2 and glucose transporters(GLUTs)or peroxisome proliferator-activated receptorγ(PPARγ)was established by western blot,and glucose consumption of trophoblasts was measured by a glucose assay kit.The results showed that the genotype and allele frequencies of rs10830963 were significantly different between GDM and normal pregnant women(P<0.05).The fasting,1-h and 2-h plasma glucose levels of G-allele carriers were significantly higher than those of C-allele carriers(P<0.05).Besides,the protein and messenger RNA(mRNA)expression of MT2 in the placenta of GDM was significantly higher than that of normal pregnant women(P<0.05).Melatonin could stimulate glucose uptake and GLUT4 and PPARγprotein expression in trophoblasts,which could be attenuated by MT2 receptor knockdown.In conclusion,the rs10830963 variant was associated with an increased risk of GDM.The MT2 receptor is essential for melatonin to raise glucose uptake and transport,which may be mediated by PPARγ.

Effect of exercise during pregnancy on offspring development through ameliorating high glucose and hypoxia in gestational diabetes mellitus

BACKGROUND Gestational diabetes mellitus(GDM)women require prenatal care to minimize short-and long-term complications.The mechanism by which exercise during pregnancy affects organ development and whether glucose transporter(GLUT)1 plays a role in GDM offspring organ development remains unknown.AIM To determine the effect of exercise during pregnancy on the cardiac,hepatic and renal development of GDM mother’s offspring.METHODS Placenta samples were collected from humans and mice.GDM mouse models were created using streptozotocin along with a GDM with exercise group.The hearts,livers and kidneys of 3-and 8-week-old offspring were collected for body composition analysis and staining.The effects of high glucose levels and hypoxia were investigated using HTR8/SVneo.Transwell and wound-healing assays were performed to assess cell migration.Immunofluorescence accompanied with TUNEL and Ki67 staining was used to explore apoptosis and proliferation.RESULTS Exercise during pregnancy downregulated the GLUT1 and hypoxia inducible factor-1αexpression in placenta from individuals with GDM.Cobalt chloride induced hypoxia and high glucose levels also significantly decreased migration and apoptosis of HTR8/SVneo cells.In addition,exercise reduced inflammatory cell infiltration in the liver and decreased the tubular vacuolar area in the kidneys of offspring.CONCLUSION GDM affects the growth and development of organs in offspring.Exercise during pregnancy can reverse adverse effects of GDM on the development of the heart,liver,and kidney in offspring.